Neurologische Klinik und Poliklinik
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Dysregulated IGFBP5 expression causes axon degeneration and motoneuron loss in diabetic neuropathy
(2015)
Diabetic neuropathy (DNP), afflicting sensory and motor nerve fibers, is a major complication in diabetes.The underlying cellular mechanisms of axon degeneration are poorly understood. IGFBP5, an inhibitory binding protein for insulin-like growth factor 1 (IGF1) is highly up-regulated in nerve biopsies of patients with DNP. We investigated the pathogenic relevance of this finding in transgenic mice overexpressing IGFBP5 in motor axons and sensory nerve fibers. These mice develop motor axonopathy and sensory deficits similar to those seen in DNP. Motor axon degeneration was also observed in mice in which the IGF1 receptor(IGF1R) was conditionally depleted in motoneurons, indicating that reduced activity of IGF1 on IGF1R in motoneurons is responsible for the observed effect. These data provide evidence that elevated expression of IGFBP5 in diabetic nerves reduces the availability of IGF1 for IGF1R on motor axons, thus leading to progressive neurodegeneration. Inhibition of IGFBP5 could thus offer novel treatment strategies for DNP.
Die hereditäre Spinalparalyse SPG17 ist eine autosomal-dominant vererbte Motoneuronerkrankung, welche durch Mutationen im BSCL2 (Seipin) Gen verursacht wird. Klassischerweise äußert sich die Krankheit durch eine spastische Paraparese der Beine und Amyotrophie der Hände (Silver-Syndrom) oder eine vorwiegend periphere (senso-)motorische Neuropathie. Für die vorliegende Arbeit wurden insgesamt sieben Patienten aus vier verschiedenen Familien, bei denen heterozygote Mutationen im BSCL2 Gen nachgewiesen werden konnten, klinisch sowie elektrophysiologisch und molekulargenetisch untersucht. Es gelang hierbei zwei bisher unbekannte phänotypische Ausprägungen zu beschreiben, welche die Symptomatik und den Verlauf einer Multifokalen Motorischen Neuropathie (MMN) bzw. einer Amyotrophen Lateralsklerose (ALS) imitieren und hiervon nur durch den genetischen Befund zu unterscheiden sind. Anhand dieser Ergebnisse erfolgte dann nach extensiver Literaturrecherche eine Zusammenfassung aller bisher publizierten Fälle der SPG17 und eine Einordnung der hier erstbeschriebenen Phänotypen in einen Vorschlag zur Erweiterung des bisher verwendeten Klassifikationssystems von BSCL 2 Mutationen.
Background:
Deep brain stimulation (DBS) is the chronic electrical stimulation of selected target sites in the brain through stereotactically implanted electrodes. More than 150 000 patients around the world have been treated to date with DBS for medically intractable conditions. The indications for DBS include movement disorders, epilepsy, and some types of mental illness.
Methods:
This review is based on relevant publications retrieved by a selective search in PubMed and the Cochrane Library, and on the current guidelines of the German Neurological Society (Deutsche Gesellschaft fur Neurologie, DGN).
Results: DBS is usually performed to treat neurological diseases, most often movement disorders and, in particular, Parkinson's disease. Multiple randomized controlled trials (RCTs) have shown that DBS improves tremor, dyskinesia, and quality of life in patients with Parkinson's disease by 25% to 50%, depending on the rating scales used. DBS for tremor usually involves stimulation in the cerebello-thalamo-cortical regulatory loop. In an RCT of DBS for the treatment of primary generalized dystonia, the patients who underwent DBS experienced a 39.3% improvement of dystonia, compared to only 4.9% in the control group. Two multicenter trials of DBS for depression were terminated early because of a lack of efficacy.
Conclusion:
DBS is an established treatment for various neurological and psychiatric diseases. It has been incorporated in the DGN guidelines and is now considered a standard treatment for advanced Parkinson's disease. The safety and efficacy of DBS can be expected to improve with the application of new technical developments in electrode geometry and new imaging techniques. Controlled trials would be helpful so that DBS could be extended to further indications, particularly psychiatric ones.
Lymphocytes express potassium channels that regulate physiological cell functions, such as activation, proliferation and migration. Expression levels of K\(_{2P}\)5.1(TASK2; KCNK5) channels belonging to the family of two-pore domain potassium channels have previously been correlated to the activity of autoreactive T lymphocytes in patients with multiple sclerosis and rheumatoid arthritis. In humans, K\(_{2P}\)5.1 channels are upregulated upon T cell stimulation and influence T cell effector functions. However, a further clinical translation of targeting K\(_{2P}\)5.1 is currently hampered by a lack of highly selective inhibitors, making it necessary to evaluate the impact of KCNK5 in established preclinical animal disease models. We here demonstrate that K\(_{2P}\)5.1 knockout (K\(_{2P}\)5.1\(^{-/-}\) mice display no significant alterations concerning T cell cytokine production, proliferation rates, surface marker molecules or signaling pathways. In an experimental model of autoimmune neuroinflammation, K\(_{2P}\)5.1\(^{-/-}\) mice show a comparable disease course to wild-type animals and no major changes in the peripheral immune system or CNS compartment. A compensatory upregulation of the potassium channels K\(_{2P}\)3.1 and K\(_{V}\)1.3 seems to counterbalance the deletion of K\(_{2P}\)5.1. As an alternative model mimicking autoimmune neuroinflammation, experimental autoimmune encephalomyelitis in the common marmoset has been proposed, especially for testing the efficacy of new potential drugs. Initial experiments show that K\(_{2P}\)5.1 is functionally expressed on marmoset T lymphocytes, opening up the possibility for assessing future K\(_{2P}\)5.1-targeting drugs.
Biomedical research suffers from a dramatically poor translational success. For example, in ischemic stroke, a condition with a high medical need, over a thousand experimental drug targets were unsuccessful. Here, we adopt methods from clinical research for a late-stage pre-clinical meta-analysis (MA) and randomized confirmatory trial (pRCT) approach. A profound body of literature suggests NOX\(_{2}\) to be a major therapeutic target in stroke. Systematic review and MA of all available NOX\(_{2}\)\(^{-/y}\) studies revealed a positive publication bias and lack of statistical power to detect a relevant reduction in infarct size. A fully powered multi-center pRCT rejects NOX\(_{2}\) as a target to improve neurofunctional outcomes or achieve a translationally relevant infarct size reduction. Thus stringent statistical thresholds, reporting negative data and a MA-pRCT approach can ensure biomedical data validity and overcome risks of bias.
Polyneuropathien sind eine ätiologisch heterogene Erkrankung des peripheren Nervensystems. In bis zu 30% der Fälle ist eine Zuordnung zu einem bestimmten PNP Subtyp auch nach aufwändiger und zum Teil invasiver Diagnostik nicht möglich. Bislang fehlt ein diagnostischer Biomarker bei PNP, der z.B. bei der Unterscheidung zwischen einzelnen diagnostischen Subgruppen oder entzündlichen und nicht-entzündlichen Erkrankungsformen helfen könnte. In einer prospektiven Studie mit insgesamt 97 Patienten mit Neuropathien verschiedenster Ätiologie und 17 gesunden Kontrollpersonen erstellten wir Genexpressionsprofile von inflammatorischen Markern und Markern der Regeneration peripherer Nerven in Haut- und N. suralis-Biopsaten. Es wurden Inflammationsmarker (TAC1, CRMP2, AIF1, IL-6) und Marker, die in die Regeneration peripherer Nerven involviert sind (SCD, Netrin-1, DCC, UNC5H2, NEO1, Netrin-G1, Netrin-G2), mittels qRT-PCR untersucht. Alle Patienten erhielten eine N. suralis-Biopsie und/oder eine Hautbiopsie von Ober- beziehungsweise Unterschenkel. Weder in den Haut- noch in den N. suralis-Biopsaten konnten Unterschiede in der Genexpression dieser Marker zwischen einzelnen diagnostischen Subgruppen gefunden werden. Der Inflammationsmarker AIF1 war jedoch in Patienten-Hautproben sowohl proximal als auch distal höher exprimiert als bei gesunden Kontrollpersonen (p < 0,05 bzw. p < 0,01). Zudem fand sich in den Hautproben von PNP-Patienten eine deutlich reduzierte Genexpression von Regenerationsmarkern aus der Netrin-Familie verglichen mit den Hautproben gesunder Probanden (Netrin-1, DCC, UNC5H2, NEO1 sowie Netrin-G1 und G2; p < 0,05 bis p < 0,001). Ferner wies Netrin-1 in distalen Hautproben bei Patienten mit einer entzündlichen PNP eine niedrigere Genexpression auf, als bei Patienten mit einer nicht-entzündlichen Erkrankungsform (p < 0,05). Die Genexpression von NEO1 in distalen Hautproben war bei schmerzloser PNP und gesunden Kontrollpersonen höher als bei schmerzhafter PNP (p < 0,05). Sowohl eine Erhöhung bestimmter Inflammationsmarker als auch eine Verminderung von Regenerationsmarkern peripherer Nerven können bei der Pathophysiologie von Polyneuropathien involviert sein. Insbesondere Mitglieder der Netrin-Familie scheinen eine komplexe Rolle für das Axonwachstum, jedoch auch für entzündliche Prozesse zu spielen.
Die Charcot-Marie-Tooth Typ 1 Erkrankungen sind eine genetisch heterogene Gruppe, aktuell nicht kurativ therapierbarer, erblicher Neuropathien des Peripheren Nervensystems. Klinische Manifestationen reichen von Sensibilitäts-störungen, verminderten Muskeleigenreflexen, sowie fortschreitenden Lähmungen, bis hin zu Muskelatrophie und bedeuten für die betroffenen Patienten eine starke Einschränkung der Lebensqualität. Anhand früherer Studien wurde Makrophagen, als Teil des angeborenen Immunsystems, eine entscheidende Rolle in der Pathogenese dreier CMT1-Unterformen zugeschrieben. Abgesehen von den morphologischen Manifestationen der demyelinisierenden CMT1-Erkrankungen, wie simultanes Auftreten von Dedifferenzierung, sowie Hypo-, und Demyelinisierung erkrankter Schwann-Zellen, sind pathologische Veränderungen der Domänengliederung der Ranvier’schen Schnürringe betroffener Nervenfasern ebenfalls von der Aktivierung pathogener Makrophagen abhängig.
Auf der Basis verschiedener veröffentlichter Studien, welche sowohl demyelinisierende Erkrankungen des ZNS, aber auch primär durch axonale Schäden gekennzeichnete Erkrankungen des PNS beinhalten, besteht ein möglicher räumlicher Zusammenhang zwischen Architekturstörungen der RS und aktivierten pathogenen Mikrogliazellen bzw. Makrophagen.
In dieser Studie konnte, anhand morphologischer Analysen von peripherem Nervengewebe, in Wt-Mäusen erstmals eine unerwartete präferentielle Lokalisation von Makrophagen im räumlichen Umfeld von RS beobachtet werden. Hierbei scheint, trotz des Fehlens einer direkten Zell-Zell-Interaktion zwischen Makrophagen und RS, vor allem im Hinblick auf die ebenfalls im räumlichen Umfeld von RS nachweisbare EZM und Fibroblasten, eine funktionelle Relevanz der assoziierten Makrophagen für die Aufrechterhaltung der Domänengliederung bzw. elektrophysiologischen Eigenschaften myelinisierter peripherer Nervenfasern denkbar.
Im Gegensatz dazu wurde trotz der signifikanten Zunahme der Makrophagenanzahlen in den drei untersuchten CMT1-Mausmodellen keine erhöhte räumliche Assoziation mit den RS der mutierten Schwann-Zellen beobachtet. Vielmehr konnten anhand des Vergleiches mit wildtypischen Kontrollmäusen signifikant erniedrigte Assoziationsraten beider Strukturen in den CMT1-Modelltieren festgestellt werden. Folglich scheint die von der Einwanderung und Aktivierung pathogener Makrophagen abhängige Störung der Domänengliederung der RS der mutierten Schwann-Zellen, nicht durch eine direkte Interaktion bzw. räumliche Assoziation von Makrophagen mit RS ausgelöst zu werden.
Intrathecal, Polyspecific Antiviral Immune Response in Oligoclonal Band Negative Multiple Sclerosis
(2012)
Background: Oligoclonal bands (OCB) are detected in the cerebrospinal fluid (CSF) in more than 95% of patients with multiple sclerosis (MS) in the Western hemisphere. Here we evaluated the intrathecal, polyspecific antiviral immune response as a potential diagnostic CSF marker for OCB-negative MS patients.
Methodology/Principal Findings: We tested 46 OCB-negative German patients with paraclinically well defined, definite MS. Sixteen OCB-negative patients with a clear diagnosis of other autoimmune CNS disorders and 37 neurological patients without evidence for autoimmune CNS inflammation served as control groups. Antibodies against measles, rubella, varicella zoster and herpes simplex virus in paired serum and CSF samples were determined by ELISA, and virus-specific immunoglobulin G antibody indices were calculated. An intrathecal antibody synthesis against at least one neurotropic virus was detected in 8 of 26 (31%) patients with relapsing-remitting MS, 8 of 12 (67%) with secondary progressive MS and 5 of 8 (63%) with primary progressive MS, in 3 of 16 (19%) CNS autoimmune and 3 of 37 (8%) non-autoimmune control patients. Antibody synthesis against two or more viruses was found in 11 of 46 (24%) MS patients but in neither of the two control groups. On average, MS patients with a positive antiviral immune response were older and had a longer disease duration than those without.
Conclusion: Determination of the intrathecal, polyspecific antiviral immune response may allow to establish a CSF-supported diagnosis of MS in OCB-negative patients when two or more of the four virus antibody indices are elevated.
Das ON-Freezing ist ein seltenes, aber generell extrem schwer zu therapierendes Phänomen. Es betrifft Parkinson-Patienten mit und ohne THS.
Die derzeitige Literaturlage spiegelt wider, dass es unterschiedliche Strategien gibt, diesem Phänomen zu begegnen. Ein allgemeingültiges Therapiekonzept existiert dabei nicht. Für einige Patienten mit STN-THS konnte durch eine Reduktion der Stimulationsfrequenz eine Besserung der Gangstörung erzielt werden. Andere profitierten vom Einsatz sogenannter Interleaving-Protokolle mit gleichzeitiger Stimulation der Substantia nigra (Sn).
Im Vergleich zu anderen Arbeiten, die keine vorhersagbaren Parameter gefunden oder sich auf Symptome, Ausprägung der Subtypen und Erkrankungsdauer oder
den Zeitpunkt der Erkrankung konzentriert haben, verfolgten wir die Absicht, die Effekte der LF-Stim des STN auf Parkinson-Patienten mit Gangstörung und Freezing-Phänomen zu untersuchen und herauszufinden, ob man Gangparameter identifizieren kann, an Hand derer man das Ansprechen auf eine LF-Stim vorhersagen kann.
Unter der Einschränkung, dass die Zahl der Probanden unserer Studie sehr gering ist, haben wir herausgefunden, dass diejenigen Patienten besser auf eine LF-Stim ansprechen, die unter der Standard-HF-Stim eine signifikant höhere Ganggeschwindigkeit und eine größere Schrittlänge aufzeigen und nur ein intermittierendes Freezing haben.
Darüber hinaus zeigte sich ein besseres Ansprechen der LF-Stim bei Parkinson-Patienten mit akinetisch-rigidem Parkinson-Phänotyp.
Unsere Ergebnisse bestätigen die Annahme, dass sich L-Dopa additiv zur Stimulationstherapie bei manchen Parkinson-Patienten zusätzlich positiv auf die motorischen PD-Symptome auswirken kann. In Bezug auf die Verbesserung der Gangparameter zeigte sich in unseren Ergebnissen allerdings, dass L-Dopa eher eine untergeordnete Rolle spielt.
Aufgrund der niedrigen Anzahl von Respondern in unserer Studie lässt sich daher sicherlich noch keine allgemeingültige Regel ableiten. Es bedarf letztlich weiterer Studien mit größeren Untersuchungszahlen, um unsere Thesen zu stützen und abzusichern.
In jedem Fall wird aber das ON-Freezing auch weiterhin eine therapeutische Herausforderung bleiben.
Isolated generalized dystonia is a central motor network disorder characterized by twisted movements or postures. The most frequent genetic cause is a GAG deletion in the Tor1a (DYT1) gene encoding torsinA with a reduced penetrance of 30-40 % suggesting additional genetic or environmental modifiers. Development of dystonia-like movements after a standardized peripheral nerve crush lesion in wild type (wt) and Tor1a+/- mice, that express 50 % torsinA only, was assessed by scoring of hindlimb movements during tail suspension, by rotarod testing and by computer-assisted gait analysis. Western blot analysis was performed for dopamine transporter (DAT), D1 and D2 receptors from striatal and quantitative RT-PCR analysis for DAT from midbrain dissections. Autoradiography was used to assess the functional DAT binding in striatum. Striatal dopamine and its metabolites were analyzed by high performance liquid chromatography. After nerve crush injury, we found abnormal posturing in the lesioned hindlimb of both mutant and wt mice indicating the profound influence of the nerve lesion (15x vs. 12x relative to control) resembling human peripheral pseudodystonia. In mutant mice the phenotypic abnormalities were increased by about 40 % (p < 0.05). This was accompanied by complex alterations of striatal dopamine homeostasis. Pharmacological blockade of dopamine synthesis reduced severity of dystonia-like movements, whereas treatment with L-Dopa aggravated these but only in mutant mice suggesting a DYT1 related central component relevant to the development of abnormal involuntary movements. Our findings suggest that upon peripheral nerve injury reduced torsinA concentration and environmental stressors may act in concert in causing the central motor network dysfunction of DYT1 dystonia.
Fabry disease is an X-linked lysosomal storage disorder due to impaired activity of alpha-galactosidase A with intracellular accumulation of globotriaosylceramide. Associated small fiber pathology leads to characteristic pain in Fabry disease. We systematically assessed sensory system, physical activity, metabolic parameters, and morphology of male and female mice with alpha-galactosidase A deficiency (Fabry ko) from 2 to 27 months of age and compared results with those of age- and gender-matched wild-type littermates of C57Bl/6J background. Results From the age of two months, male and female Fabry mice showed mechanical hypersensitivity (p < 0.001 each) compared to wild-type littermates. Young Fabry ko mice of both genders were hypersensitive to heat stimulation (p < 0.01) and developed heat hyposensitivity with aging (p < 0.05), while cold hyposensitivity was present constantly in young (p < 0.01) and old (p < 0.05) Fabry ko mice compared to wild-type littermates. Stride angle increased only in male Fabry ko mice with aging (p < 0.01) in comparison to wild-type littermates. Except for young female mice, male (p < 0.05) and female (p < 0.01) Fabry ko mice had a higher body weight than wild-type littermates. Old male Fabry ko mice were physically less active than their wild-type littermates (p < 0.05), had lower chow intake (p < 0.001), and lost more weight (p < 0.001) in a one-week treadmill experiment than wild-type littermates. Also, Fabry ko mice showed spontaneous pain protective behavior and developed orofacial dysmorphism resembling patients with Fabry disease.
Conclusions. Mice with alpha-galactosidase A deficiency show age-dependent and distinct deficits of the sensory system. alpha-galactosidase A-deficient mice seem to model human Fabry disease and may be helpful when studying the pathophysiology of Fabry-associated pain.
Background
Traumatic brain injury (TBI) is a major cause of death and disability. Neuroinflammation contributes to acute damage after TBI and modulates long-term evolution of degenerative and regenerative responses to injury. The aim of the present study was to evaluate the relationship of microglia activation to trauma severity, brain energy metabolism, and cellular reactions to injury in a mouse closed head injury model using combined in vivo PET imaging, ex vivo autoradiography, and immunohistochemistry.
Methods
A weight-drop closed head injury model was used to produce a mixed diffuse and focal TBI or a purely diffuse mild TBI (mTBI) in C57BL6 mice. Lesion severity was determined by evaluating histological damage and functional outcome using a standardized neuroscore (NSS), gliosis, and axonal injury by immunohistochemistry. Repeated intra-individual in vivo μPET imaging with the specific 18-kDa translocator protein (TSPO) radioligand [\(^{18}\)F]DPA-714 was performed on day 1, 7, and 16 and [\(^{18}\)F]FDG-μPET imaging for energy metabolism on days 2–5 after trauma using freshly synthesized radiotracers. Immediately after [\(^{18}\)F]DPA-714-μPET imaging on days 7 and 16, cellular identity of the [\(^{18}\)F]DPA-714 uptake was confirmed by exposing freshly cut cryosections to film autoradiography and successive immunostaining with antibodies against the microglia/macrophage marker IBA-1.
Results
Functional outcome correlated with focal brain lesions, gliosis, and axonal injury. [\(^{18}\)F]DPA-714-μPET showed increased radiotracer uptake in focal brain lesions on days 7 and 16 after TBI and correlated with reduced cerebral [\(^{18}\)F]FDG uptake on days 2–5, with functional outcome and number of IBA-1 positive cells on day 7. In autoradiography, [\(^{18}\)F]DPA-714 uptake co-localized with areas of IBA1-positive staining and correlated strongly with both NSS and the number of IBA1-positive cells, gliosis, and axonal injury. After mTBI, numbers of IBA-1 positive cells with microglial morphology increased in both brain hemispheres; however, uptake of [\(^{18}\)F]DPA-714 was not increased in autoradiography or in μPET imaging.
Conclusions
[\(^{18}\)F]DPA-714 uptake in μPET/autoradiography correlates with trauma severity, brain metabolic deficits, and microglia activation after closed head TBI.
From October 30–November 1, 2015, the 7th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. Seventy doctoral students and postdocs from over 25 different groups working in German and Swiss University Hospitals or Research Institutes attended the meeting to discuss their latest experiments and findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. This meeting report summarizes the many diverse presentations and the new preclinical to clinical neurology research data that were shared by the participants at the meeting.
Background
Serotonin (5-hydroxytryptamin, 5-HT) is an indolamine platelet agonist, biochemically derived from tryptophan. 5-HT is secreted from the enterochromaffin cells into the gastrointestinal tract and blood. Blood 5-HT has been proposed to regulate hemostasis by acting as a vasoconstrictor and by triggering platelet signaling through 5-HT receptor 2A (5HTR2A). Although platelets do not synthetize 5-HT, they take 5-HT up from the blood and store it in their dense granules which are secreted upon platelet activation.
Objective
To identify the molecular composite of the 5-HT uptake system in platelets and elucidate the role of platelet released 5-HT in thrombosis and ischemic stroke. Methods: 5-HT transporter knockout mice (5Htt\(^{-/-}\)) were analyzed in different in vitro and in vivo assays and in a model of ischemic stroke.
Results
In 5Htt\(^{-/-}\) platelets, 5-HT uptake from the blood was completely abolished and agonist-induced Ca2+ influx through store operated Ca\(^{2+}\) entry (SOCE), integrin activation, degranulation and aggregation responses to glycoprotein VI (GPVI) and C-type lectin-like receptor 2 (CLEC-2) were reduced. These observed in vitro defects in 5Htt\(^{-/-}\) platelets could be normalized by the addition of exogenous 5-HT. Moreover, reduced 5-HT levels in the plasma, an increased bleeding time and the formation of unstable thrombi were observed ex vivo under flow and in vivo in the abdominal aorta and carotid artery of 5Htt\(^{-/-}\) mice. Surprisingly, in the transient middle cerebral artery occlusion (tMCAO) model of ischemic stroke 5Htt\(^{-/-}\) mice showed nearly normal infarct volume and the neurological outcome was comparable to control mice.
Conclusion
Although secreted platelet 5-HT does not appear to play a crucial role in the development of reperfusion injury after stroke, it is essential to amplify the second phase of platelet activation through SOCE and plays an important role in thrombus stabilization.
Background
Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. In this series, the image quality and value of intraoperative 3D fluoroscopy with intravenous contrast agent for the evaluation of aneurysm occlusion and vessel patency after clip placement was assessed in patients who underwent surgery for intracranial aneurysms.
Materials and methods
Twelve patients were included in this retrospective analysis. Prior to surgery, a 360° rotational fluoroscopy scan was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac® workstation, subtracted and reconstructed using OsiriX® free software. The procedure was repeated after clip placement. Both image sets were compared for assessment of aneurysm occlusion and vessel patency.
Results
Image acquisition and contrast administration caused no adverse effects. Image quality was sufficient to follow the patency of the vessels distal to the clip. Metal artifacts reduce the assessability of the immediate vicinity of the clip. Precise image subtraction and post-processing can reduce metal artifacts and make the clip-site assessable and depict larger neck-remnants.
Conclusion
This technique quickly supplies images at adequate quality to evaluate distal vessel patency after aneurysm clipping. Significant aneurysm remnants may be depicted as well. As it does not require visual control of all vessels that are supposed to be evaluated intraoperatively, this technique may be complementary to other intraoperative tools like indocyanine green videoangiography and micro-Doppler, especially for the assessment of larger aneurysms. At the momentary state of this technology, it cannot replace postoperative conventional angiography. However, 3D fluoroscopy and image post-processing are young technologies. Further technical developments are likely to result in improved image quality.
microRNAs in chronic pain
(2016)
Chronic pain is a common problem in clinical practice, not well understood clinically, and frequently tough to satisfactorily diagnose. Because the pathophysiology is so complex, finding effective treatments for people with chronic pain has been overall less than successful and typically reduced to an unsatisfactory trial-and-error process, all of which translates into a significant burden to society. Knowledge of the mechanisms underlying the development of chronic pain, and moreover why some patients experience pain and others not, may aid in developing specific treatment regimens. Although nerve injuries are major contributors to pain chronification, they cannot explain the entire phenomenon. Considerable research has underscored the importance of the immune system for the development and maintenance of chronic pain, albeit the exact factors regulating inflammatory reactions remain unclear. Understanding the putative molecular and cellular regulator switches of inflammatory reactions will open novel opportunities for immune modulatory analgesics with putatively higher specificity and less adverse effects. It has become clear that small, non- coding RNA molecules known as microRNAs are in fact potent regulators of many thousands of genes and possibly cross-communicate between cellular pathways in multiple systems acting as so-called “master-switches”. Aberrant expression of miRNAs is now implicated in numerous disorders, including nerve injuries as well as in inflammatory processes. Moreover, compelling evidence supports the idea that miRNAs also regulate pain, and in analogy to the oncology field aid in the differential diagnosis of disease subtypes. In fact, first reports describing characteristic miRNA expression profiles in blood or cerebrospinal fluid of patients with distinct pain conditions are starting to emerge, however evidence linking specific miRNA expression profiles to specific pain disorders is still insufficient. The present thesis aimed at first, identifying specific miRNA signatures in two distinct chronic pain conditions, namely peripheral neuropathies of different etiologies and fibromyalgia syndrome. Second, it aimed at identifying miRNA profiles to better understand potential factors that differentiate painful from painless neuropathies and third, study the mechanistic role of miRNAs in the pathophysiology of pain, to pave the way for new druggable targets.
Three studies were conducted in order to identify miRNA expression signatures that are characteristic for the given chronic pain disorder. The first study measured expression of miR-21, miR-146a and miR-155 in white blood cells, skin and nerve biopsies of patients with peripheral neuropathies. It shows that peripheral neuropathies of different etiologies are associated with increased peripheral miR-21 and miR-146a, but decreased miR-155 expression. More importantly, it was shown that painful neuropathies have increased sural nerve miR-21 and miR-155 expression, but reduced miR-146a and miR-155 expression in distal skin of painful neuropathies. These results point towards the potential use of miRNAs profiles to stratify painful neuropathies. The seconds study extends these findings and first analyzed the role of miR-132-3p in patients and subsequently in an animal model of neuropathic pain. Interestingly, miR-132-3p was upregulated in white blood cells and sural nerve biopsies of patients with painful neuropathies and in animals after spared nerve injury. Pharmacologically modulating the expression of miR-132-3p dose-dependently reversed pain behavior and pain aversion, indicating the pro-nociceptive effect of miR-132-3p in chronic pain. This study thus demonstrates the potential analgesic impact by modulating miRNA expression. Fibromyalgia is associated with chronic widespread pain and, at least in a subgroup, impairment in small nerve fiber morphology and function. Interestingly, the disease probably comprises subgroups with different underlying pathomechanisms. In accordance with this notion, the third study shows that fibromyalgia is associated with both aberrant white blood cell and cutaneous miRNA expression. Being the first of its kind, this study identified miR-let-7d and its downstream target IGF-1R as potential culprit for impaired small nerve fiber homeostasis in a subset of patients with decreased intra-epidermal nerve fiber density. The work presented in this thesis is a substantial contribution towards the goal of better characterizing chronic pain based on miRNA expression signatures and thus pave the way for new druggable targets.
Background
Fabry-associated pain may be the first symptom of Fabry disease (FD) and presents with a unique phenotype including mostly acral burning triggerable pain attacks, evoked pain, pain crises, and permanent pain. We recently developed and validated the first Fabry Pain Questionnaire (FPQ) for adult patients. Here we report on the validation of the self-administered version of the FPQ that no longer requires a face-to-face interview but can be filled in by the patients themselves allowing more flexible data collection.
Methods
At our Würzburg Fabry Center for Interdisciplinary Treatment, Germany, we have developed the self-administered version of the FPQ by adapting the questionnaire to a self-report version. To do this, consecutive Fabry patients with current or past pain history (n = 56) were first interviewed face-to-face. Two weeks later patients’ self-reported questionnaire results were collected by mail (n = 55). We validated the self-administered version of the FPQ by assessing the inter-rater reliability agreement of scores obtained by supervised administration and self-administration of the FPQ.
Results
The FPQ contains 15 questions on the different pain phenotypes, on pain development during life with and without therapy, and on impairment due to pain. Statistical analysis showed that the majority of questions were answered in high agreement in both sessions with a mean AC1-statistic of 0.857 for 55 nominal-scaled items and a mean ICC of 0.587 for 9 scores.
Conclusions
This self-administered version of the first pain questionnaire for adult Fabry patients is a useful tool to assess Fabry-associated pain without a time-consuming face-to-face interview but via a self-reporting survey allowing more flexible usage.
Susac syndrome, a rare but probably underdiagnosed combination of encephalopathy, hearing loss, and visual deficits due to branch retinal artery occlusion of unknown aetiology has to be considered as differential diagnosis in various conditions. Particularly, differentiation from multiple sclerosis is often challenging since both clinical presentation and diagnostic findings may overlap. Optical coherence tomography is a powerful and easy to perform diagnostic tool to analyse the morphological integrity of retinal structures and is increasingly established to depict characteristic patterns of retinal pathology in multiple sclerosis. Against this background we hypothesised that differential patterns of retinal pathology facilitate a reliable differentiation between Susac syndrome and multiple sclerosis. In this multicenter cross-sectional observational study optical coherence tomography was performed in nine patients with a definite diagnosis of Susac syndrome. Data were compared with age-, sex-, and disease duration-matched relapsing remitting multiple sclerosis patients with and without a history of optic neuritis, and with healthy controls. Using generalised estimating equation models, Susac patients showed a significant reduction in either or both retinal nerve fibre layer thickness and total macular volume in comparison to both healthy controls and relapsing remitting multiple sclerosis patients. However, in contrast to the multiple sclerosis patients this reduction was not distributed over the entire scanning area but showed a distinct sectorial loss especially in the macular measurements. We therefore conclude that patients with Susac syndrome show distinct abnormalities in optical coherence tomography in comparison to multiple sclerosis patients. These findings recommend optical coherence tomography as a promising tool for differentiating Susac syndrome from MS.
To determine the role of striatal dopaminergic innervation on upper limb synergies during walking, we measured arm kinematics in 13 subjects with Parkinson disease. Patients were recruited according to several inclusion criteria to represent the best possible in vivo model of dopaminergic denervation. Of relevance, we included only subjects with normal spatio-temporal parameters of the stride and gait speed to avoid an impairment of upper limbs locomotor synergies as a consequence of gait impairment per se. Dopaminergic innervation of the striatum was measured by FP-CIT and SPECT. All patients showed a reduction of gait-associated arms movement. No linear correlation was found between arm ROM reduction and contralateral dopaminergic putaminal innervation loss. Still, a partition analysis revealed a 80% chance of reduced arm ROM when putaminal dopamine content loss was >47%. A significant correlation was described between the asymmetry indices of the swinging of the two arms and dopaminergic striatal innervation. When arm ROM was reduced, we found a positive correlation between upper-lower limb phase shift modulation ( at different gait velocities) and striatal dopaminergic innervation. These findings are preliminary evidence that dopaminergic striatal tone plays a modulatory role in upper-limb locomotor synergies and upper-lower limb coupling while walking at different velocities.
We analyzed rest tremor, one of the etiologically most elusive hallmarks of Parkinson disease(PD), in 12 consecutive PD patients during a specific task activating the locus coeruleus (LC) to investigate a putative role of noradrenaline (NA) in tremor generation and suppression. Clinical diagnosis was confirmed in all subjects by reduced dopamine reuptake transporter (DAT) binding values investigated by single photon computed tomography imaging (SPECT) with [\(^{123}\)I] N-\(\omega\)-fluoropropyl-2 \(\beta\)-carbomethoxy-3 \(\beta\)-(4-iodophenyl) tropane (FP-CIT). The intensity of tremor (i.e., the power of Electromyography [EMG] signals), but not its frequency, significantly increased during the task. In six subjects, tremor appeared selectively during the task. In a second part of the study, we retrospectively reviewed SPECT with FP-CIT data and confirmed the lack of correlation between dopaminergic loss and tremor by comparing DAT binding values of 82 PD subjects with bilateral tremor (n = 27), unilateral tremor (n = 22), and no tremor (n = 33). This study suggests a role of the LC in Parkinson tremor.
Das Schädel-Hirn-Trauma (SHT) entsteht durch äußere Gewalteinwirkung auf den Kopf und verursacht mechanisch eine Schädigung des Hirngewebes. Zusätzlich tragen sekundäre Pathomechanismen, wie Entzündungsprozesse und die Schädigung der Blut-Hirn-Schranke (BHS), dazu bei, dass sich das initial geschädigte Läsionsareal im Laufe der Zeit vergrößert. Vor allem bei jungen Erwachsenen ist das SHT eine der häufigsten Ursachen für bleibende Behinderungen und Todesfälle. Aufgrund der schweren Auswirkungen des SHT und der bislang fehlenden Therapieoptionen ist die Identifizierung neuer Zielstrukturen für eine kausale Therapie von größter Bedeutung. Ausgehend von tierexperimentellen Studien ist das Kallikrein-Kinin-System (KKS) ein besonders erfolgversprechender Angriffspunkt zur Behandlung des SHT. Die Aktivierung des KKS über den Gerinnungsfaktor XII (FXII) und die darauf folgende Bildung von Bradykinin sind mit dem Entstehen von Hirnödemen und Entzündungsreaktionen assoziiert. Vorangegangene Studien haben weiterhin die Frage aufgeworfen, ob und in welchem Maße thrombotische Prozesse einen Einfluss auf die Pathophysiologie und die sekundären Hirnschädigungen nach SHT haben. Da FXII sowohl das KKS als auch die intrinsische plasmatische Gerinnungskaskade initiiert und somit zur Fibrinbildung beiträgt, stand FXII im Mittelpunkt der Untersuchungen dieser Dissertation. Die vorliegende Arbeit beschäftigt sich mit den Fragen, (I) inwiefern FXII eine Rolle bei der sekundären Hirnschädigung nach Trauma spielt und (II) ob thrombotische Prozesse ein pathophysiologisches Merkmal nach Trauma darstellen. In zwei unterschiedlichen Trauma-Modellen wurden FXII-defiziente Tiere und mit einem spezifischen Inhibitor des aktivierten FXII (FXIIa) behandelte Tiere gegen Kontrolltiere nach SHT verglichen. Die Analyse der funktionellen Ausfallerscheinungen und des Ausmaßes an neuronaler Degeneration zeigte, dass FXII-Defizienz und FXIIa-Inhibition vor den Auswirkungen eines SHT schützen. Als zugrundeliegende Mechanismen wurden die Reduktion von thrombotisch verschlossenen Gefäßen in der Mikrovaskulatur des Gehirns sowie der Schutz vor BHS-Störungen und verringerte inflammatorische Prozesse identifiziert. Weiterhin wurde festgestellt, dass eine Blockade der intrinsischen Gerinnungskaskade über FXII keine intrazerebralen Blutungen auslöst. In Gewebeproben von Patienten mit SHT wurde gezeigt, dass Thrombozytenaggregate auch im klinischen Verlauf auftreten und sich somit die tierexperimentellen Befunde auf die humane Situation übertragen lassen. Insgesamt tragen die Ergebnisse dazu bei, die komplexen und vielfältigen Pathomechanismen nach SHT besser zu verstehen und vor allem die Relevanz thrombo-inflammatorischer Prozesse nach SHT aufzuzeigen. Die gezielte Blockade des FXII(a) könnte als therapeutisches Prinzip zur Abschwächung der Sekundärschaden nach SHT geeignet sein.
Background: The diagnostic and pathophysiological relevance of antibodies to aquaporin-4 (AQP4-Ab) in patients with neuromyelitis optica spectrum disorders (NMOSD) has been intensively studied. However, little is known so far about the clinical impact of AQP4-Ab seropositivity.
Objective: To analyse systematically the clinical and paraclinical features associated with NMO spectrum disorders in Caucasians in a stratified fashion according to the patients' AQP4-Ab serostatus.
Methods: Retrospective study of 175 Caucasian patients (AQP4-Ab positive in 78.3%).
Results: Seropositive patients were found to be predominantly female (p < 0.0003), to more often have signs of co-existing autoimmunity (p < 0.00001), and to experience more severe clinical attacks. A visual acuity of <= 0.1 during acute optic neuritis (ON) attacks was more frequent among seropositives (p < 0.002). Similarly, motor symptoms were more common in seropositive patients, the median Medical Research Council scale (MRC) grade worse, and MRC grades <= 2 more frequent, in particular if patients met the 2006 revised criteria (p < 0.005, p < 0.006 and p < 0.01, respectively), the total spinal cord lesion load was higher (p < 0.006), and lesions >= 6 vertebral segments as well as entire spinal cord involvement more frequent (p < 0.003 and p < 0.043). By contrast, bilateral ON at onset was more common in seronegatives (p < 0.007), as was simultaneous ON and myelitis (p < 0.001); accordingly, the time to diagnosis of NMO was shorter in the seronegative group (p < 0.029). The course of disease was more often monophasic in seronegatives (p < 0.008). Seropositives and seronegatives did not differ significantly with regard to age at onset, time to relapse, annualized relapse rates, outcome from relapse (complete, partial, no recovery), annualized EDSS increase, mortality rate, supratentorial brain lesions, brainstem lesions, history of carcinoma, frequency of preceding infections, oligoclonal bands, or CSF pleocytosis. Both the time to relapse and the time to diagnosis was longer if the disease started with ON (p < 0.002 and p < 0.013). Motor symptoms or tetraparesis at first myelitis and > 1 myelitis attacks in the first year were identified as possible predictors of a worse outcome.
Background: Pioglitazone, an oral anti-diabetic that stimulates the PPAR-gamma transcription factor, increased survival of mice with amyotrophic lateral sclerosis (ALS).
Methods/Principal Findings: We performed a phase II, double blind, multicentre, placebo controlled trial of pioglitazone in ALS patients under riluzole. 219 patients were randomly assigned to receive 45 mg/day of pioglitazone or placebo (one: one allocation ratio). The primary endpoint was survival. Secondary endpoints included incidence of non-invasive ventilation and tracheotomy, and slopes of ALS-FRS, slow vital capacity, and quality of life as assessed using EUROQoL EQ-5D. The study was conducted under a two-stage group sequential test, allowing to stop for futility or superiority after interim analysis. Shortly after interim analysis, 30 patients under pioglitazone and 24 patients under placebo had died. The trial was stopped for futility; the hazard ratio for primary endpoint was 1.21 (95% CI: 0.71-2.07, p = 0.48). Secondary endpoints were not modified by pioglitazone treatment. Pioglitazone was well tolerated.
Conclusion/Significance: Pioglitazone has no beneficial effects on the survival of ALS patients as add-on therapy to riluzole.
Interleukin-4 (IL-4) is an anti-inflammatory and analgesic cytokine that induces opioid receptor transcription. We investigated IL-4 knockout (ko) mice to characterize their pain behavior before and after chronic constriction injury (CCI) of the sciatic nerve as a model for neuropathic pain. We investigated opioid responsivity and measured cytokine and opioid receptor gene expression in the peripheral and central nervous system (PNS, CNS) of IL-4 ko mice in comparison with wildtype (wt) mice. Naïve IL-4 ko mice displayed tactile allodynia (wt: 0.45 g; ko: 0.18 g; p<0.001), while responses to heat and cold stimuli and to muscle pressure were not different. No compensatory changes in the gene expression of tumor necrosis factor-alpha (TNF), IL-1β, IL-10, and IL-13 were found in the PNS and CNS of naïve IL-4 ko mice. However, IL-1β gene expression was stronger in the sciatic nerve of IL-4 ko mice (p<0.001) 28 days after CCI and only IL-4 ko mice had elevated IL-10 gene expression (p = 0.014). Remarkably, CCI induced TNF (p<0.01), IL-1β (p<0.05), IL-10 (p<0.05), and IL-13 (p<0.001) gene expression exclusively in the ipsilateral spinal cord of IL-4 ko mice. The compensatory overexpression of the anti-inflammatory and analgesic cytokines IL-10 and IL-13 in the spinal cord of IL-4 ko mice may explain the lack of genotype differences for pain behavior after CCI. Additionally, CCI induced gene expression of μ, κ, and δ opioid receptors in the contralateral cortex and thalamus of IL-4 ko mice, paralleled by fast onset of morphine analgesia, but not in wt mice. We conclude that a lack of IL-4 leads to mechanical sensitivity; the compensatory hyperexpression of analgesic cytokines and opioid receptors after CCI, in turn, protects IL-4 ko mice from enhanced pain behavior after nerve lesion.
In Vivo Imaging of Stepwise Vessel Occlusion in Cerebral Photothrombosis of Mice by \(^{19}\)F MRI
(2011)
Background
\(^{19}\)F magnetic resonance imaging (MRI) was recently introduced as a promising technique for in vivo cell tracking. In the present study we compared \(^{19}\)F MRI with iron-enhanced MRI in mice with photothrombosis (PT) at 7 Tesla. PT represents a model of focal cerebral ischemia exhibiting acute vessel occlusion and delayed neuroinflammation.
Methods/Principal Findings
Perfluorocarbons (PFC) or superparamagnetic iron oxide particles (SPIO) were injected intravenously at different time points after photothrombotic infarction. While administration of PFC directly after PT induction led to a strong \(^{19}\)F signal throughout the entire lesion, two hours delayed application resulted in a rim-like \(^{19}\)F signal at the outer edge of the lesion. These findings closely resembled the distribution of signal loss on T2-weighted MRI seen after SPIO injection reflecting intravascular accumulation of iron particles trapped in vessel thrombi as confirmed histologically. By sequential administration of two chemically shifted PFC compounds 0 and 2 hours after illumination the different spatial distribution of the \(^{19}\)F markers (infarct core/rim) could be visualized in the same animal. When PFC were applied at day 6 the fluorine marker was only detected after long acquisition times ex vivo. SPIO-enhanced MRI showed slight signal loss in vivo which was much more prominent ex vivo indicative for neuroinflammation at this late lesion stage.
Conclusion
Our study shows that vessel occlusion can be followed in vivo by \(^{19}\)F and SPIO-enhanced high-field MRI while in vivo imaging of neuroinflammation remains challenging. The timing of contrast agent application was the major determinant of the underlying processes depicted by both imaging techniques. Importantly, sequential application of different PFC compounds allowed depiction of ongoing vessel occlusion from the core to the margin of the ischemic lesions in a single MRI measurement.
Background
"Negative affect" is one of the major migraine triggers. The aim of the study was to assess attentional biases for negative affective stimuli that might be related to migraine triggers in migraine patients with either few or frequent migraine and healthy controls.
Methods
Thirty-three subjects with frequent migraine (FM) or with less frequent episodic migraine, and 20 healthy controls conducted two emotional Stroop tasks in the interictal period. In task 1, general affective words and in task 2, pictures of affective faces (angry, neutral, happy) were used. For each task we calculated two emotional Stroop indices. Groups were compared using one-way ANOVAs.
Results
The expected attentional bias in migraine patients was not found. However, in task 2 the controls showed a significant attentional bias to negative faces, whereas the FM group showed indices near zero. Thus, the FM group responded faster to negative than to positive stimuli. The difference between the groups was statistically significant.
Conclusions
The findings in the FM group may reflect a learned avoidance mechanism away from affective migraine triggers.
Background: Despite pleiotropic immunomodulatory effects of apolipoprotein E (apoE) in vitro, its effects on the clinical course of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS) are still controversial. As sex hormones modify immunomodulatory apoE functions, they may explain contentious findings. This study aimed to investigate sex-specific effects of apoE on disease course of EAE and MS.
Methods: MOG\(_{35-55}\) induced EAE in female and male apoE-deficient mice was assessed clinically and histopathologically. apoE expression was investigated by qPCR. The association of the MS severity score (MSSS) and APOE rs429358 and rs7412 was assessed across 3237 MS patients using linear regression analyses.
Results: EAE disease course was slightly attenuated in male apoE-deficient (apoE\(^{-/-}\)) mice compared to wildtype mice (cumulative median score: apoE\(^{-/-}\) = 2 [IQR 0.0-4.5]; wildtype = 4 [IQR 1.0-5.0]; n = 10 each group, p = 0.0002). In contrast, EAE was more severe in female apoE\(^{-/-}\) mice compared to wildtype mice (cumulative median score: apoE\(^{-/-}\) = 3 [IQR 2.0-4.5]; wildtype = 3 [IQR 0.0-4.0]; n = 10, p = 0.003). In wildtype animals, apoE expression during the chronic EAE phase was increased in both females and males (in comparison to naive animals; p < 0.001). However, in MS, we did not observe a significant association between MSSS and rs429358 or rs7412, neither in the overall analyses nor upon stratification for sex.
Conclusions: apoE exerts moderate sex-specific effects on EAE severity. However, the results in the apoE knock-out model are not comparable to effects of polymorphic variants in the human APOE gene, thus pinpointing the challenge of translating findings from the EAE model to the human disease.
The two bradykinin receptors B1R and B2R are central components of the kallikrein–kinin system with different expression kinetics and binding characteristics. Activation of these receptors by kinins triggers inflammatory responses in the target organ and in most situations enhances tissue damage. We could recently show that blocking of B1R, but not B2R, protects from cortical cryolesion by reducing inflammation and edema formation. In the present study, we investigated the role of B1R and B2R in a closed head model of focal traumatic brain injury (TBI; weight drop). Increased expression of B1R in the injured hemispheres of wild-type mice was restricted to the later stages after brain trauma, i.e. day 7 (P<0.05), whereas no significant induction could be observed for the B2R (P>0.05). Mice lacking the B1R, but not the B2R, showed less functional deficits on day 3 (P<0.001) and day 7 (P<0.001) compared with controls. Pharmacological blocking of B1R in wild-type mice had similar effects. Reduced axonal injury and astroglia activation could be identified as underlying mechanisms, while inhibition of B1R had only little influence on the local inflammatory response in this model. Inhibition of B1R may become a novel strategy to counteract trauma-induced neurodegeneration.
The 7th International Symposium on Neuroprotection and Neurorepair was held from May 2nd to May 5th, 2012 in Potsdam, Germany. The symposium, which directly continues the successful Magdeburg meeting series, attracted over 330 colleagues from 29 countries to discuss recent findings and advances in the field. The focus of the 2012 symposium was widened from stroke and traumatic brain injury to neurodegenerative diseases, notably dementia, and more generally the ageing brain. Thereby, emphasis was given on neurovascular aspects of neurodegeneration and stroke including the blood–brain barrier, recent findings regarding the pathomechanism of Alzheimer’s disease, and brain imaging approaches. In addition, neurobiochemical aspects of neuroprotection, the role of astrogliosis, the clinical progress of cell-based approaches as well as translational hurdles and opportunities were discussed in-depth. This review summarizes some of the most stimulating discussions and reports from the meeting.
The present antithrombotic drugs used to treat or prevent ischemic stroke have significant limitations: either they show only moderate efficacy (platelet inhibitors), or they significantly increase the risk for hemorrhages (thrombolytics, anticoagulants). Although most strokes are caused by thrombotic or embolic vessel occlusions, the pathophysiological role of platelets and coagulation is largely unclear. The introduction of novel transgenic mouse models and specific coagulation inhibitors facilitated a detailed analysis of molecular pathways mediating thrombus formation in models of acute ischemic stroke. Prevention of early platelet adhesion to the damaged vessel wall by blocking platelet surface receptors glycoprotein Ib alpha (GPIbα) or glycoprotein VI (GPVI) protects from stroke without provoking bleeding complications. In addition, downstream signaling of GPIbα and GPVI has a key role in platelet calcium homeostasis and activation. Finally, the intrinsic coagulation cascade, activated by coagulation factor XII (FXII), has only recently been identified as another important mediator of thrombosis in cerebrovascular disease, thereby disproving established concepts. This review summarizes the latest insights into the pathophysiology of thrombus formation in the ischemic brain. Potential clinical merits of novel platelet inhibitors and anticoagulants as powerful and safe tools to combat ischemic stroke are discussed.
NKG2D is an activating receptor on T cells, which has been implicated in the pathogenesis of autoimmune diseases. T cells are critically involved in idiopathic inflammatory myopathies (IIM) and have been proposed as specific therapeutic targets. However, the mechanisms underlying T cell-mediated progressive muscle destruction in IIM remain to be elucidated. We here determined the involvement of the NKG2D - IL-15 signaling pathway. Primary human myoblasts expressed NKG2D ligands, which were further upregulated upon inflammatory stimuli. In parallel, shedding of the soluble NKG2D ligand MICA (sMICA) decreased upon inflammation potentially diminishing inhibition of NKG2D signaling. Membrane-related expression of IL-15 by myoblasts induced differentiation of naive CD8\(^+\) T cells into highly activated, cytotoxic \(CD8^+NKG2D^{high}\) T cells demonstrating NKG2D-dependent lysis of myoblasts in vitro. \(CD8^+NKG2D^{high}\) T cell frequencies were increased in the peripheral blood of polymyositis (PM) patients and correlated with serum creatinine kinase concentrations, while serum sMICA levels were not significantly changed. In muscle biopsy specimens from PM patients expression of the NKG2D ligand MICA/B was upregulated, IL-15 was expressed by muscle cells, CD68\(^+\) macrophages as well as CD4\(^+\) T cells, and \(CD8^+NKG2D^+\) cells were frequently detected within inflammatory infiltrates arguing for a local signaling circuit in the inflammatory muscle milieu. In conclusion, the NKG2D - IL-15 signaling pathway contributes to progressive muscle destruction in IIM potentially opening new therapeutic avenues.
Die Rolle thromboinflammatorischer Vorgänge in der Pathogenese des ischämischen Schlaganfalls ist in den letzten Jahren immer mehr in den wissenschaftlichen Fokus gerückt. Plasmakallikrein (PK) spaltet von hochmolekularem Kininogen (KNG) Bradykinin (BK) ab und ist dadurch Ausgangspunkt des proinflammatorischen Kallikrein-Kinin-Systems (KKS). Zum anderen kann es den Gerinnungsfaktor XII (FXII) aktivieren, den Ausgangspunkt der intrinsischen Gerinnungskaskade. Es initiiert also sowohl inflammatorische als auch thrombotische Vorgänge. Daher wurde in dieser Arbeit der Effekt einer Blockade PKs in einem Mausmodell der fokalen zerebralen Ischämie untersucht – und zwar sowohl durch genetische Depletion als auch durch pharmakologische Blockade. Beide Ansätze brachten einen nachhaltigen protektiven Effekt in Bezug auf Infarktgrößen und funktionelles Outcome, ohne die Blutungsgefahr zu erhöhen.
Studying the function and malfunction of genes and proteins associated with inherited forms of peripheral neuropathies has provided multiple clues to our understanding of myelinated nerves in health and disease. Here, we have generated a mouse model for the peripheral neuropathy Charcot–Marie–Tooth disease type 4H by constitutively disrupting the mouse orthologue of the suspected culprit gene FGD4 that encodes the small RhoGTPase Cdc42-guanine nucleotide exchange factor Frabin. Lack of Frabin/Fgd4 causes dysmyelination in mice in early peripheral nerve development, followed by profound myelin abnormalities and demyelination at later stages. At the age of 60 weeks, this was accompanied by electrophysiological deficits. By crossing mice carrying alleles of Frabin/Fgd4 flanked by loxP sequences with animals expressing Cre recombinase in a cell type-specific manner, we show that Schwann cell-autonomous Frabin/Fgd4 function is essential for proper myelination without detectable primary contributions from neurons. Deletion of Frabin/Fgd4 in Schwann cells of fully myelinated nerve fibres revealed that this protein is not only required for correct nerve development but also for accurate myelin maintenance. Moreover, we established that correct activation of Cdc42 is dependent on Frabin/Fgd4 function in healthy peripheral nerves. Genetic disruption of Cdc42 in Schwann cells of adult myelinated nerves resulted in myelin alterations similar to those observed in Frabin/Fgd4-deficient mice, indicating that Cdc42 and the Frabin/Fgd4–Cdc42 axis are critical for myelin homeostasis. In line with known regulatory roles of Cdc42, we found that Frabin/Fgd4 regulates Schwann cell endocytosis, a process that is increasingly recognized as a relevant mechanism in peripheral nerve pathophysiology. Taken together, our results indicate that regulation of Cdc42 by Frabin/Fgd4 in Schwann cells is critical for the structure and function of the peripheral nervous system. In particular, this regulatory link is continuously required in adult fully myelinated nerve fibres. Thus, mechanisms regulated by Frabin/Fgd4–Cdc42 are promising targets that can help to identify additional regulators of myelin development and homeostasis, which may crucially contribute also to malfunctions in different types of peripheral neuropathies.
Introduction: Reversible posterior leukoencephalopathy syndrome – a reversible subacute global encephalopathy clinically presenting with headache, altered mental status, visual symptoms such as hemianopsia or cortical blindness, motor symptoms, and focal or generalized seizures – is characterized by a subcortical vasogenic edema symmetrically affecting posterior brain regions. Complete reversibility of both clinical signs and magnetic resonance imaging lesions is regarded as a defining feature of reversible posterior leukoencephalopathy syndrome. Reversible posterior leukoencephalopathy syndrome is almost exclusively seen in the setting of a predisposing clinical condition, such as pre-eclampsia, systemic infections, sepsis and shock, certain autoimmune diseases, various malignancies and cytotoxic chemotherapy, transplantation and concomitant immunosuppression (especially with calcineurin inhibitors) as well as episodes of abrupt hypertension. We describe for the first time clinical, radiological and histological findings in a case of reversible posterior leukoencephalopathy syndrome with an irreversible and fatal outcome occurring in the absence of any of the known predisposing clinical conditions except for a hypertensive episode.
Case presentation: A 58-year-old Caucasian woman presented with a two-week history of subacute and progressive occipital headache, blurred vision and imbalance of gait and with no evidence for raised arterial blood pressure during the two weeks previous to admission. Her past medical history was unremarkable except for controlled arterial hypertension. Cerebral magnetic resonance imaging demonstrated cortical and subcortical lesions with combined vasogenic and cytotoxic edema atypical for both venous congestion and arterial infarction. Routine laboratory and cerebrospinal fluid parameters were normal. The diagnosis of reversible posterior leukoencephalopathy syndrome was established.
Within hours after admission the patient showed a rapidly decreasing level of consciousness, extension and flexion synergisms, bilaterally extensor plantar responses and rapid cardiopulmonary decompensation requiring ventilatory and cardiocirculatory support. Follow-up cerebral imaging demonstrated widespread and confluent cytotoxic edematous lesions in different arterial territories, global cerebral swelling, and subsequent upper and lower brainstem herniation. Four days after admission, the patient was declared dead because of brain death.
Conclusion: This case demonstrates that fulminant and fatal reversible posterior leukoencephalopathy syndrome may occur spontaneously, that is, in the absence of any of the known predisposing systemic conditions.
Background
Brain ischemia is known to include neuronal cell death and persisting neurological deficits. A lack of oxygen and glucose are considered to be key mediators of ischemic neurodegeneration while the exact mechanisms are yet unclear. In former studies the expression of two different two-pore domain potassium \((K_{2P})\) channels (TASK1, TREK1) were shown to ameliorate neuronal damage due to cerebral ischemia. In neurons, TASK channels carrying hyperpolarizing \(K^+\) leak currents, and the pacemaker channel HCN2, carrying depolarizing \(I_h\), stabilize the membrane potential by a mutual functional interaction. It is assumed that this ionic interplay between TASK and HCN2 channels enhances the resistance of neurons to insults accompanied by extracellular pH shifts.
Methods
In C57Bl/6 (wildtype, WT), \(hcn2^{+/+}\) and \(hcn2^{-/-}\) mice we used an in vivo model of cerebral ischemia (transient middle cerebral artery occlusion (tMCAO)) to depict a functional impact of HCN2 in stroke formation. Subsequent analyses comprise behavioural tests and hcn2 gene expression assays.
Results
After 60 min of tMCAO induction in WT mice, we collected tissue samples at 6, 12, and 24 h after reperfusion. In the infarcted neocortex, hcn2 expression analyses revealed a nominal peak of hcn2 expression 6 h after reperfusion with a tendency towards lower expression levels with longer reperfusion times. Hcn2 gene expression levels in infarcted basal ganglia did not change after 6 h and 12 h. Only at 24 h after reperfusion, hcn2 expression significantly decreases by ~55%. However, 30 min of tMCAO in hcn2-/- as well as hcn2+/+ littermates induced similar infarct volumes. Behavioural tests for global neurological function (Bederson score) and motor function/coordination (grip test) were performed at day 1 after surgery. Again, we found no differences between the groups.
Conclusions
Here, we hypothesized that the absence of HCN2, an important functional counter player of TASK channels, affects neuronal survival during stroke-induced tissue damage. However, together with a former study on TASK3 these results implicate that both TASK3 and HCN2 which were supposed to be neuroprotective due to their pH-dependency, do not influence ischemic neurodegeneration during stroke in the tMCAO model.
From october 25th - 27th 2013, the 5th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. This year more than 60 doctoral students and postdocs from over 25 different groups working in German university hospitals or research institutes attended the meeting to discuss their latest findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. All participants appreciated the stimulating environment in Motzen, Brandenburg, and people took the opportunity for scientific exchange, discussion about ongoing projects and already started further collaborations. Like in the previous years, the symposium was regarded as a very well organized platform to support research of young investigators in Germany.
According to the major aim of NEUROWIND e.V. to support younger researchers in Germany the 3rd NEUROWIND YOUNG SCIENTIST AWARD for experimental neurology was awarded to Ruth Stassart working in the group of Klaus Armin Nave and Wolfgang Brück (MPI Göttingen and Department of Neuropathology, Göttingen Germany). The successful work was published in Nature Neuroscience entitled “A role for Swann cell-derived neuregulin-1 in remyelination”. This outstanding paper deals with the function of Schwann cell neuregulin as an endogenous factor for myelin repair. The award is endowed with 20.000 Euro sponsored by Merck Serono GmbH, Darmstadt, Germany (unrestricted educational grant). This year’s keynote lecture was given by Albert Ludolph, Head of the Department of Neurology at the University Clinic of Ulm. Dr. Ludolph highlighted the particular role of individual scientists for the development of research concepts in Alzheimer´s disease (AD) and frontotemporal dementia (FTD).
Das Körperselbstgefühl (KSG) bezeichnet das Gefühl, einen bestimmten Kör-perteil als dem eigenen Körper zugehörig zu empfinden. Es erscheint stabil und nicht störbar, lässt sich jedoch bei den meisten Menschen experimentell beein-flussen. Ein Beispiel hierfür ist die Puppenhandillusion (PHI), bei der die nicht sichtbare eigene Hand des Probanden und eine sichtbare Plastikhand in glei-cher Stellung an den gleichen Fingerstellen synchron mit zwei Pinseln bestri-chen wird, wodurch die Wahrnehmung entsteht, die Plastikhand sei die eigene. Veränderungen des KSG können jedoch auch im Rahmen neurodegenerativer Erkrankungen vorkommen. So nimmt beim kortikobasalen Syndrom (CBS) etwa die Hälfte der Patienten im Krankheitsverlauf einen Arm und seine Bewegungen als fremd war ("Alien-limb“-Phänomen). Das CBS beginnt oft einseitig und ist durch eine rasch fortschreitende, akinetisch-rigide Parkinson-Symptomatik, aber auch durch kortikale Funktionsstörungen gekennzeichnet, so dass es ne-ben einer Störung des KSG auch zu einer Störung der räumlichen Aufmerk-samkeit (Hemineglect) kommt. Bislang wurde der Zusammenhang zwischen Raumwahrnehmung, KSG und PHI bei gesunden älteren Menschen noch nicht systematisch untersucht. Ebenso wenig war bisher bekannt, inwieweit das KSG bei CBS-Patienten durch die PHI modulierbar ist. Wir untersuchten 65 gesunde ältere Probanden (60 - 90 Jahre) ohne neurologi-sche Vorerkrankungen sowie zehn Patienten zwischen 59 und 77 Jahren mit wahrscheinlichem oder möglichem CBS. Den kognitiven und orientierend seeli-schen Zustand eruierten wir mit Hilfe des PANDA- und des Uhrentests, die Raumwahrnehmung testeten wir mittels des Milner-Landmark-Tests sowie des Letter-Cancellation-Tests, das spontane Körperselbstgefühl wurde mittels eines Fragebogens erfasst. Der PHI-Versuch wurde mit synchroner sowie asynchro-ner taktiler Stimulation durchgeführt, das Auftreten eines Selbstgefühls für die Plastikhand wurde subjektiv über spontane Äußerungen und einen etablierten Fragebogen, objektiv über den sog. propriozeptiven Drift der stimulierten Hand erfasst. Unter den Kontrollprobanden fanden sich 12% mit einer wahrscheinlichen De-menz, wohingegen dies bei 80% der CBS-Patienten der Fall war. Im Milner-Landmark-Test zeigte sich bei den Kontrollprobanden eine Überschätzung des rechten Segmentes einer mittig geteilten Linie, entsprechend einem milden Hemineglect, bei den CBS-Patienten konnte keine einheitliche Tendenz festge-stellt werden. Das spontane Körperselbstgefühl stellte sich bei nahezu allen Probanden als intakt dar, während sich bei vier Patienten mit CBS Hinweise auf aktuelle oder intermittierende Störungen desselben ergaben. Die Puppenhandil-lusion war in der Gruppe gesunder Älterer bei synchroner Stimulation auslös-bar, nicht jedoch bei asynchroner Stimulation. Eine Lateralisierungstendenz zeigte sich nicht. Darüber hinaus konnte bei den Probanden eine positive Korre-lation zwischen dem propriozeptiven Drift der linken Hand nach synchroner Stimulation und dem Hemineglect nach links gefunden werden. Bei den CBS-Patienten fand sich unabhängig von der Stimulationsart (synchron oder asyn-chron) eine erhöhte Bereitschaft, die linke Puppenhand ins eigene Körperbild zu integrieren. Das Auftreten der PHI bei gesunden älteren Probanden ist vergleichbar mit den Daten jüngerer Probandengruppen. Hinweise auf eine hemisphärische Laterali-sierungstendenz der PHI ergaben sich nicht, jedoch scheint der in dieser Grup-pe festgestellte leichtgradige Hemineglect nach links den multisensorischen Prozess zu beeinflussen, eine künstliche Hand in das eigene Körperschema zu integrieren. Bei den CBS-Patienten war die PHI unabhängig vom Stimulations-modus links besser auslösbar als rechts, was mit vorwiegend rechtshemisphä-rischen krankheitsbedingten Veränderungen des multisensorischen Integrati-onsprozesses vereinbar ist.
Motor complications in Parkinson’s disease (PD) result from the short half-life and irregular plasma fluctuations of oral levodopa. When strategies of providing more continuous dopaminergic stimulation by adjusting oral medication fail, patients may be candidates for one of three device-aided therapies: deep brain stimulation (DBS), continuous subcutaneous apomorphine infusion, or continuous duodenal/jejunal levodopa/carbidopa pump infusion (DLI). These therapies differ in their invasiveness, side-effect profile, and the need for nursing care. So far, very few comparative studies have evaluated the efficacy of the three device-aided therapies for specific motor problems in advanced PD. As a result, neurologists currently lack guidance as to which therapy could be most appropriate for a particular PD patient. A group of experts knowledgeable in all three therapies reviewed the currently available literature for each treatment and identified variables of clinical relevance for choosing one of the three options such as type of motor problems, age, and cognitive and psychiatric status. For each scenario, pragmatic and (if available) evidence-based recommendations are provided as to which patients could be candidates for either DBS, DLI, or subcutaneous apomorphine.
Introduction: Reversible posterior leukoencephalopathy syndrome – a reversible subacute global encephalopathy clinically presenting with headache, altered mental status, visual symptoms such as hemianopsia or cortical blindness, motor symptoms, and focal or generalized seizures – is characterized by a subcortical vasogenic edema symmetrically affecting posterior brain regions. Complete reversibility of both clinical signs and magnetic resonance imaging lesions is regarded as a defining feature of reversible posterior leukoencephalopathy syndrome. Reversible posterior leukoencephalopathy syndrome is almost exclusively seen in the setting of a predisposing clinical condition, such as pre-eclampsia, systemic infections, sepsis and shock, certain autoimmune diseases, various malignancies and cytotoxic chemotherapy, transplantation and concomitant immunosuppression (especially with calcineurin inhibitors) as well as episodes of abrupt hypertension. We describe for the first time clinical, radiological and histological findings in a case of reversible posterior leukoencephalopathy syndrome with an irreversible and fatal outcome occurring in the absence of any of the known predisposing clinical conditions except for a hypertensive episode.
Case presentation: A 58-year-old Caucasian woman presented with a two-week history of subacute and progressive occipital headache, blurred vision and imbalance of gait and with no evidence for raised arterial blood pressure during the two weeks previous to admission. Her past medical history was unremarkable except for controlled arterial hypertension. Cerebral magnetic resonance imaging demonstrated cortical and subcortical lesions with combined vasogenic and cytotoxic edema atypical for both venous congestion and arterial infarction. Routine laboratory and cerebrospinal fluid parameters were normal. The diagnosis of reversible posterior leukoencephalopathy syndrome was established. Within hours after admission the patient showed a rapidly decreasing level of consciousness, extension and flexion synergisms, bilaterally extensor plantar responses and rapid cardiopulmonary decompensation requiring ventilatory and cardiocirculatory support. Follow-up cerebral imaging demonstrated widespread and confluent cytotoxic edematous lesions in different arterial territories, global cerebral swelling, and subsequent upper and lower brainstem herniation. Four days after admission, the patient was declared dead because of brain death.
Conclusion: This case demonstrates that fulminant and fatal reversible posterior leukoencephalopathy syndrome may occur spontaneously, that is, in the absence of any of the known predisposing systemic conditions.
Background
Brain ischemia is known to include neuronal cell death and persisting neurological deficits. A lack of oxygen and glucose are considered to be key mediators of ischemic neurodegeneration while the exact mechanisms are yet unclear. In former studies the expression of two different two-pore domain potassium \((K_{2P})\) channels (TASK1, TREK1) were shown to ameliorate neuronal damage due to cerebral ischemia. In neurons, TASK channels carrying hyperpolarizing \(K^+\) leak currents, and the pacemaker channel HCN2, carrying depolarizing Ih, stabilize the membrane potential by a mutual functional interaction. It is assumed that this ionic interplay between TASK and HCN2 channels enhances the resistance of neurons to insults accompanied by extracellular pH shifts.
Methods
In C57Bl/6 (wildtype, WT), \(hcn2^{+/+}\) and \(hcn2^{-/-}\) mice we used an in vivo model of cerebral ischemia (transient middle cerebral artery occlusion (tMCAO)) to depict a functional impact of HCN2 in stroke formation. Subsequent analyses comprise behavioural tests and hcn2 gene expression assays.
Results
After 60 min of tMCAO induction in WT mice, we collected tissue samples at 6, 12, and 24 h after reperfusion. In the infarcted neocortex, hcn2 expression analyses revealed a nominal peak of hcn2 expression 6 h after reperfusion with a tendency towards lower expression levels with longer reperfusion times. Hcn2 gene expression levels in infarcted basal ganglia did not change after 6 h and 12 h. Only at 24 h after reperfusion, hcn2 expression significantly decreases by ~55%. However, 30 min of tMCAO in hcn2-/- as well as hcn2+/+ littermates induced similar infarct volumes. Behavioural tests for global neurological function (Bederson score) and motor function/coordination (grip test) were performed at day 1 after surgery. Again, we found no differences between the groups.
Conclusions
Here, we hypothesized that the absence of HCN2, an important functional counter player of TASK channels, affects neuronal survival during stroke-induced tissue damage. However, together with a former study on TASK3 these results implicate that both TASK3 and HCN2 which were supposed to be neuroprotective due to their pH-dependency, do not influence ischemic neurodegeneration during stroke in the tMCAO model.
Die vorliegende Arbeit ist die erste, die sich mit der Frage beschäftigt, mit welcher zur Deeskalation eingesetzten Therapie nach Beendigung einer Eskalationstherapie mit Mitoxantron am besten Krankheitsstabilität erreicht werden kann bzw. ob Patienten-/Krankheitscharakteristika existieren, die eine bestimmte Nachfolge-Therapie favorisieren.
Trotz neuer Behandlungsmöglichkeiten der hochaktiven MS mit Fingolimod, Natalizumab und Alemtuzumab hat Mitoxantron im klinischen Alltag nach wie vor einen hohen Stellenwert, so dass die Fragestellung dieser Studie weiter relevant ist.
Es zeigten sich keine Patientencharakteristika, die auf eine erfolgsversprechende Therapie in der Deeskalationsphase nach Mitoxantron schließen ließen.
Bei Patienten, bei denen während der Eskalation mit Mitoxantron die Dosis reduziert werden konnte, wurden während der Deeskalationstherapie ein stabilerer Verlauf und weniger Therapiewechsel beobachtet. Bei Patienten, die wegen einer rein chronischen Krankheitsprogredienz eskaliert wurden, trat eine Verschlechterung nach Deeskalation häufiger auf als bei denjenigen, welche wegen Schubaktivität eskaliert wurden.
Die Aussagekraft der Daten wird durch die nur niedrige Anzahl der in diese Studie eingeschlossenen Patienten limitiert. Rekrutierungsprobleme stellten die Hauptursache für die geringe Anzahl der Studienteilnehmer dar.
Treatment of dysferlinopathy with deflazacort: a double-blind, placebo-controlled clinical trial
(2013)
Background: Dysferlinopathies are autosomal recessive disorders caused by mutations in the dysferlin (DYSF) gene encoding the dysferlin protein. DYSF mutations lead to a wide range of muscular phenotypes, with the most prominent being Miyoshi myopathy (MM) and limb girdle muscular dystrophy type 2B (LGMD2B).
Methods: We assessed the one-year-natural course of dysferlinopathy, and the safety and efficacy of deflazacort treatment in a double-blind, placebo-controlled cross-over trial. After one year of natural course without intervention, 25 patients with genetically defined dysferlinopathy were randomized to receive deflazacort and placebo for six months each (1 mg/kg/day in month one, 1 mg/kg every 2nd day during months two to six) in one of two treatment sequences. Results: During one year of natural course, muscle strength declined about 2% as measured by CIDD (Clinical Investigation of Duchenne Dystrophy) score, and 76 Newton as measured by hand-held dynamometry. Deflazacort did not improve muscle strength. In contrast, there is a trend of worsening muscle strength under deflazacort treatment, which recovers after discontinuation of the study drug. During deflazacort treatment, patients showed a broad spectrum of steroid side effects.
Conclusion: Deflazacort is not an effective therapy for dysferlinopathies, and off-label use is not warranted. This is an important finding, since steroid treatment should not be administered in patients with dysferlinopathy, who may be often misdiagnosed as polymyositis.
Background: Hereditary spastic paraplegias (HSPs) are characterised by lower limb spasticity due to degeneration of the corticospinal tract. We set out for an electrophysiological characterisation of motor and sensory tracts in patients with HSP.
Methods: We clinically and electrophysiologically examined a cohort of 128 patients with genetically confirmed or clinically probable HSP. Motor evoked potentials (MEPs) to arms and legs, somato-sensory evoked potentials of median and tibial nerves, and nerve conduction studies of tibial, ulnar, sural, and radial nerves were assessed.
Results: Whereas all patients showed clinical signs of spastic paraparesis, MEPs were normal in 27% of patients and revealed a broad spectrum with axonal or demyelinating features in the others. This heterogeneity can at least in part be explained by different underlying genotypes, hinting for distinct pathomechanisms in HSP subtypes. In the largest subgroup, SPG4, an axonal type of damage was evident. Comprehensive electrophysiological testing disclosed a more widespread affection of long fibre tracts involving peripheral nerves and the sensory system in 40%, respectively. Electrophysiological abnormalities correlated with the severity of clinical symptoms.
Conclusions: Whereas HSP is primarily considered as an upper motoneuron disorder, our data suggest a more widespread affection of motor and sensory tracts in the central and peripheral nervous system as a common finding in HSP. The distribution patterns of electrophysiological abnormalities were associated with distinct HSP genotypes and could reflect different underlying pathomechanisms. Electrophysiological measures are independent of symptomatic treatment and may therefore serve as a reliable biomarker in upcoming HSP trials.
Objective. Current evidence indicates that there is no single ideal treatment for fibromyalgia syndrome (FMS). First choice treatment options remain debatable, especially concerning the importance of complementary and alternative medicine (CAM) treatments. Methods. Three evidence-based interdisciplinary guidelines on FMS in Canada, Germany, and Israel were compared for their first choice and CAM-recommendations. Results. All three guidelines emphasized a patient-tailored approach according to the key symptoms. Aerobic exercise, cognitive behavioral therapy, and multicomponent therapy were first choice treatments. The guidelines differed in the grade of recommendation for drug treatment. Anticonvulsants (gabapentin, pregabalin) and serotonin noradrenaline reuptake inhibitors (duloxetine, milnacipran) were strongly recommended by the Canadian and the Israeli guidelines. These drugs received only a weak recommendation by the German guideline. In consideration of CAM-treatments, acupuncture, hypnosis/guided imagery, and Tai Chi were recommended by the German and Israeli guidelines. The Canadian guidelines did not recommend any CAM therapy. Discussion. Recent evidence-based interdisciplinary guidelines concur on the importance of treatment tailored to the individual patient and further emphasize the need of self-management strategies (exercise, and psychological techniques).
This review addresses the current status of drug therapy for the management of fibromyalgia syndrome (FMS) and is based on interdisciplinary FMS management guidelines, meta-analyses of drug trial data, and observational studies. In the absence of a single gold-standard medication, patients are treated with a variety of drugs from different categories, often with limited evidence. Drug therapy is not mandatory for the management of FMS. Pregabalin, duloxetine, milnacipran, and amitriptyline are the current first-line prescribed agents but have had a mostly modest effect. With only a minority of patients expected to experience substantial benefit, most will discontinue therapy because of either a lack of efficacy or tolerability problems. Many drug treatments have undergone limited study and have had negative results. It is unlikely that these failed pilot trials will undergo future study. However, medications, though imperfect, will continue to be a component of treatment strategy for these patients. Both the potential for medication therapy to relieve symptoms and the potential to cause harm should be carefully considered in their administration.
GTP cyclohydrolase 1, encoded by the GCH1 gene, is an essential enzyme for dopamine production in nigrostriatal cells. Loss-of-function mutations in GCH1 result in severe reduction of dopamine synthesis in nigrostriatal cells and are the most common cause of DOPA-responsive dystonia, a rare disease that classically presents in childhood with generalized dystonia and a dramatic long-lasting response to levodopa. We describe clinical, genetic and nigrostriatal dopaminergic imaging ([(123)I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) tropane single photon computed tomography) findings of four unrelated pedigrees with DOPA-responsive dystonia in which pathogenic GCH1 variants were identified in family members with adult-onset parkinsonism. Dopamine transporter imaging was abnormal in all parkinsonian patients, indicating Parkinson's disease-like nigrostriatal dopaminergic denervation. We subsequently explored the possibility that pathogenic GCH1 variants could contribute to the risk of developing Parkinson's disease, even in the absence of a family history for DOPA-responsive dystonia. The frequency of GCH1 variants was evaluated in whole-exome sequencing data of 1318 cases with Parkinson's disease and 5935 control subjects. Combining cases and controls, we identified a total of 11 different heterozygous GCH1 variants, all at low frequency. This list includes four pathogenic variants previously associated with DOPA-responsive dystonia (Q110X, V204I, K224R and M230I) and seven of undetermined clinical relevance (Q110E, T112A, A120S, D134G, I154V, R198Q and G217V). The frequency of GCH1 variants was significantly higher (Fisher's exact test P-value 0.0001) in cases (10/1318 = 0.75%) than in controls (6/5935 = 0.1%; odds ratio 7.5; 95% confidence interval 2.4-25.3). Our results show that rare GCH1 variants are associated with an increased risk for Parkinson's disease. These findings expand the clinical and biological relevance of GTP cycloydrolase 1 deficiency, suggesting that it not only leads to biochemical striatal dopamine depletion and DOPA-responsive dystonia, but also predisposes to nigrostriatal cell loss. Further insight into GCH1-associated pathogenetic mechanisms will shed light on the role of dopamine metabolism in nigral degeneration and Parkinson's disease.
The ganglioside-induced differentiation-associated protein 1 (GDAP1) is a mitochondrial fission factor and mutations in GDAP1 cause Charcot–Marie–Tooth disease. We found that Gdap1 knockout mice (\(Gdap1^{−/−}\)), mimicking genetic alterations of patients suffering from severe forms of Charcot–Marie–Tooth disease, develop an age-related, hypomyelinating peripheral neuropathy. Ablation of Gdap1 expression in Schwann cells recapitulates this phenotype. Additionally, intra-axonal mitochondria of peripheral neurons are larger in \(Gdap1^{−/−}\) mice and mitochondrial transport is impaired in cultured sensory neurons of \(Gdap1^{−/−}\) mice compared with controls. These changes in mitochondrial morphology and dynamics also influence mitochondrial biogenesis. We demonstrate that mitochondrial DNA biogenesis and content is increased in the peripheral nervous system but not in the central nervous system of \(Gdap1^{−/−}\) mice compared with control littermates. In search for a molecular mechanism we turned to the paralogue of GDAP1, GDAP1L1, which is mainly expressed in the unaffected central nervous system. GDAP1L1 responds to elevated levels of oxidized glutathione by translocating from the cytosol to mitochondria, where it inserts into the mitochondrial outer membrane. This translocation is necessary to substitute for loss of GDAP1 expression. Accordingly, more GDAP1L1 was associated with mitochondria in the spinal cord of aged \(Gdap1^{−/−}\) mice compared with controls. Our findings demonstrate that Charcot–Marie–Tooth disease caused by mutations in GDAP1 leads to mild, persistent oxidative stress in the peripheral nervous system, which can be compensated by GDAP1L1 in the unaffected central nervous system. We conclude that members of the GDAP1 family are responsive and protective against stress associated with increased levels of oxidized glutathione.
High-Dose Capsaicin for the Treatment of Neuropathic Pain: What We Know and What We Need to Know
(2014)
Neuropathic pain is a frequent and disabling condition with diverse underlying etiologies and is often difficult to treat. Systemic drug treatment is often limited in efficacy. Furthermore, adverse effects may be a limiting factor when trying to reach the necessary dose. Analgesics that can be applied topically have the potential to largely overcome this problem. They may be of particular advantage in localized neuropathic pain syndromes such as postherpetic neuralgia or small fiber neuropathy. Capsaicin, the pungent component of chili peppers, is a natural ligand of the transient receptor potential vanilloid 1 channel and has long been used as topically applicable cream with concentrations of 0.025 to 0.075%. In 2009, a high-concentration transdermal capsaicin 8% patch (Qutenza ; Acorda Therapeutics, Inc., Ardsley, NY, USA; Astellas Pharma Europe Ltd., Chertsey, Surrey, UK) was introduced for the treatment of peripheral neuropathic pain syndromes other than of diabetic origin in adults. It has since been widely used in diverse neuropathic pain disorders. In this review article, we summarize current knowledge on Qutenza, its advantages and problems, and expose unmet needs.
INTRODUCTION:
B cells are attracting increasing attention in the pathogenesis of multiple sclerosis (MS). B cell-targeted therapies with monoclonal antibodies or plasmapheresis have been shown to be successful in a subset of patients. Here, patients with either relapsing-remitting (n = 24) or secondary progressive (n = 6) MS presenting with an acute clinical relapse were screened for their B cell reactivity to brain antigens and were re-tested three to nine months later. Enzyme-linked immunospot technique (ELISPOT) was used to identify brain-reactive B cells in peripheral blood mononuclear cells (PBMC) directly ex vivo and after 96 h of polyclonal stimulation. Clinical severity of symptoms was determined using the Expanded Disability Status Scale (EDSS).
RESULTS:
Nine patients displayed B cells in the blood producing brain-specific antibodies directly ex vivo. Six patients were classified as B cell positive donors only after polyclonal B cell stimulation. In 15 patients a B cell response to brain antigens was absent. Based on the autoreactive B cell response we categorized MS relapses into three different patterns. Patients who displayed brain-reactive B cell responses both directly ex vivo and after polyclonal stimulation (pattern I) were significantly younger than patients in whom only memory B cell responses were detectable or entirely absent (patterns II and III; p = 0.003). In one patient a conversion to a positive B cell response as measured directly ex vivo and subsequently also after polyclonal stimulation was associated with the development of a clinical relapse. The evaluation of the predictive value of a brain antigen-specific B cell response showed that seven of eight patients (87.5%) with a pattern I response encountered a clinical relapse during the observation period of 10 months, compared to two of five patients (40%) with a pattern II and three of 14 patients (21.4%) with a pattern III response (p = 0.0005; hazard ratio 6.08 (95% confidence interval 1.87-19.77).
CONCLUSIONS:
Our data indicate actively ongoing B cell-mediated immunity against brain antigens in a subset of MS patients that may be causative of clinical relapses and provide new diagnostic and therapeutic options for a subset of patients.