@phdthesis{Papagianni2018,
  author    = {Papagianni, Aikaterini},
  title     = {Schmerz-assoziierte elektrisch evozierte Potentiale (PREP) bei Patienten mit neuropathischen Schmerzsyndromen},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159728},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {In der vorliegenden Studie wurden 32 Patienten (19 Frauen, 13 M{\"a}nner, medianes Alter 50 Jahren, Spanne: 26-83 Jahre) mit einem klinisch akralen neuropathischen Schmerzsyndrom unterschiedlicher Genese mittels QST, PREP und Hautbiopsie untersucht. Unser Patientenkollektiv bestand aus drei Subgruppen: sechsen Patienten erf{\"u}llten die Kriterien einer SFN, acht Patienten hatten eine Neuropathie der großkalibrigen Nervenfasern mit zus{\"a}tzlicher Beeintr{\"a}chtigung der kleinkalibrigen Nervenfasern und weitere acht Patienten hatten ein akrales Schmerzsyndrom mit neuropathischen Charakteristika, ohne vorbekannte Diagnose einer Neuropathie der groß- oder kleinkalibrigen Nervenfasern. Die Patienten wurden mittels klinischer neurologischer Untersuchung, elektrophysiologischer Tests, QST, PREP und Hautbiopsie untersucht. Die Patientendaten wurden jeweils mit Daten großer Kontrollgruppen verglichen, die wir in unserer Klinik unter Angeh{\"o}rigen und Freunden unserer Patienten mit deren Einwilligung rekrutiert hatten. QST und die Hautbiopsie waren bei Patienten mit SFN und PNP jeweils auff{\"a}llig, bei akralem Schmerzsyndrom unklarer {\"A}tiologie hingegen unauff{\"a}llig. Nach elektrischer kutaner Stimulation aller drei K{\"o}rperregionen zeigte sich eine Amplitudenminderung der PREP-Reizantwort in allen Patientensubgruppen (7,5 µV in der SFN-Gruppe, 3,8 µV in der PNP-Gruppe, und 11,3 µV bei den Patienten mit akralem Schmerzsyndrom). Somit konnten wir zeigen, dass eine Kleinfaserpathologie in der Studienpopulation von Patienten mit neuropathischem Schmerzsyndrom besteht. Nur die Amplitudenminderung der PREP bildet diese Pathologie ab. Diese Daten erlauben uns die eingangs aufgestellte Hypothese, dass PREP zur Diagnostik bei Frage nach Kleinfaserbeteiligung geeignet ist, positiv zu belegen. PREP ist eine nicht-invasive Methode f{\"u}r die Evaluation der Funktion v.a. der Aδ-Faser mit standardisiertem Ablaufprotokoll zur Erhebung von reproduzierbaren Daten. Sie kann bei Patienten mit der Anamnese eines akralen neuropathischen Schmerzsyndroms einen objektiven Hinweis auf eine Dysfunktion der kleinkalibrigen Nervenfasern, auch wenn bereits etablierte Methoden (QST und Hautbiopsie) unauff{\"a}llig bleiben, erbringen. Entsprechend k{\"o}nnen die PREP eine wertvolle Erg{\"a}nzung der klinischen Untersuchungsbatterie f{\"u}r die Evaluation der Funktion der kleinkalibrigen Nervenfasern sein.},
  subject      = {PREP},
  language  = {de}
}
@article{KlitschEvdokimovFranketal.2020,
  author    = {Klitsch, Alexander and Evdokimov, Dimitar and Frank, Johanna and Thomas, Dominique and Saffer, Nadine and Meyer zu Altenschildesche, Caren and Sisignano, Marco and Kampik, Daniel and Malik, Rayaz A. and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Reduced association between dendritic cells and corneal sub-basal nerve fibers in patients with fibromyalgia syndrome},
  series = {Journal of the Peripheral Nervous System},
  volume    = {25},
  journal   = {Journal of the Peripheral Nervous System},
  number    = {1},
  doi       = {10.1111/jns.12360},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214150},
  pages     = {9-18},
  year      = {2020},
  abstract  = {In our study, we aimed at investigating corneal langerhans cells (LC) in patients with fibromyalgia syndrome (FMS) and small fiber neuropathy (SFN) as potential contributors to corneal small fiber pathology. We enrolled women with FMS (n = 134) and SFN (n = 41) who underwent neurological examination, neurophysiology, prostaglandin analysis in tear fluid, and corneal confocal microscopy (CCM). Data were compared with those of 60 age-matched female controls. After screening for dry eye disease, corneal LC were counted and sub-classified as dendritic (dLC) and non-dendritic (ndLC) cells with or without nerve fiber association. We further analyzed corneal nerve fiber density (CNFD), length (CNFL), and branch density (CNBD). Neurological examination indicated deficits of small fiber function in patients with SFN. Nerve conduction studies were normal in all participants. Dry eye disease was more prevalent in FMS (17\%) and SFN (28\%) patients than in controls (5\%). Tear fluid prostaglandin levels did not differ between FMS patients and controls. While corneal LC density in FMS and SFN patients was not different from controls, there were fewer dLC in association with nerve fibers in FMS and SFN patients than in controls (P < .01 each). Compared to controls, CNFL was lower in FMS and SFN patients (P < .05 each), CNFD was lower only in FMS patients (P < .05), and CNBD was lower only in SFN patients (P < .001). There was no difference in any CCM parameter between patients with and without dry eyes. Our data indicate changes in corneal innervation and LC distribution in FMS and SFN, potentially based on altered LC signaling.},
  language  = {en}
}
@phdthesis{Egenolf2020,
  author    = {Egenolf, Nadine},
  title     = {Multidimensionale morphologische und elektrophysiologische Analyse von Patienten mit Small Fiber Neuropathie},
  doi       = {10.25972/OPUS-20293},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202938},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {Die Small Fiber Neuropathie (SFN) bildet eine Untergruppe der sensiblen Neuropathien, bei der die Aδ- und C-Fasern betroffen sind. Die Patienten berichten v.a. von brennenden Schmerzen und Dys{\"a}sthesien, seltener auch von autonomen Funktionsst{\"o}rungen. Bei fehlendem Goldstandard und normalen Nervenleitungsstudien ist die Diagnostik erschwert, da selbst nach Spezialuntersuchungen wie Hautstanzbiopsie und quantitativer sensorischer Testung (QST) viele Patienten trotz typischer Anamnese der Diagnosestellung entgehen. Wir rekrutierten 55 Patienten und 31 gesunde Kontrollen. Nach neurologischer Untersuchung und Ausschluss einer Polyneuropathie mittels Elektroneurographie wurden bei allen Studienteilnehmern Hautstanzbiopsien am Ober- und Unterschenkel zur Ermittlung der intraepidermalen Nervenfaserdichte (IENFD) entnommen sowie eine QST zur Funktionspr{\"u}fung der kleinen Nervenfasern durchgef{\"u}hrt. Die Studienteilnehmer wurden zudem mit cornealer confocaler Mikroskopie (CCM) und der Ableitung Schmerz-assoziierter evozierter Potentiale (PREP) untersucht. Zur autonomen Testung erfolgte die Messung der Schweißproduktion mittels quantitativem sudomotorischem Axonreflextest (QSART). Die neurologische Untersuchung zeigte in 55\% der Patienten Hinweise auf eine Kleinfaserpathologie. Die distale IENFD war bei 62\% der Patienten reduziert, die QST bei 22\% der Patienten auff{\"a}llig. Die PREP Latenzen waren in der Patientengruppe l{\"a}nger als bei den Kontrollen, die Amplituden niedriger. Bei der cornealen Innervation zeigte sich eine Reduktion der Nervenfaserdichte, Nervenfaserl{\"a}nge und Nervenastdichte. Die in QSART gemessenen Parameter zeigten sich zu 86\% unauff{\"a}llig. W{\"a}hrend nach klinischer Untersuchung, Hautbiopsie und QST in 53\% der F{\"a}lle in 2 von 3 Untersuchungen eine Pathologie der kleinen Fasern festgestellt werden konnte, stieg die Rate bei zus{\"a}tzlicher Anwendung von PREP und CCM auf 80\% (ohne Ber{\"u}cksichtigung von QST). Zusammenfassend sollten die klinische Untersuchung und die Hautstanzbiopsie bei allen Patienten mit Verdacht auf SFN erfolgen. PREP und CCM sind unter den verf{\"u}gbaren zus{\"a}tzlichen Untersuchungen diagnostisch am wertvollsten. Wichtig ist allerdings, dass bei fehlendem Goldstandard eine SFN auch bei unauff{\"a}lligen Tests nicht ausgeschlossen werden kann. Zus{\"a}tzlich k{\"o}nnen die Mikroneurographie und die genetische Analyse wertvolle Hinweise auf eine Kleinfaserfunktionsst{\"o}rung und deren Pathophysiologie geben.},
  subject      = {Neuropathischer Schmerz},
  language  = {de}
}
@article{JaenschEvdokimovEgenolfetal.2024,
  author    = {J{\"a}nsch, Sarah and Evdokimov, Dimitar and Egenolf, Nadine and Meyer zu Altenschildesche, Caren and Kreß, Luisa and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Distinguishing fibromyalgia syndrome from small fiber neuropathy: a clinical guide},
  series = {Pain Reports},
  volume    = {9},
  journal   = {Pain Reports},
  number    = {1},
  doi       = {10.1097/PR9.0000000000001136},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350306},
  year      = {2024},
  abstract  = {Introduction: Fibromyalgia syndrome (FMS) and small fiber neuropathy (SFN) are distinct pain conditions that share commonalities and may be challenging as for differential diagnosis. Objective: To comprehensively investigate clinical characteristics of women with FMS and SFN to determine clinically applicable parameters for differentiation. Methods: We retrospectively analyzed medical records of 158 women with FMS and 53 with SFN focusing on pain-specific medical and family history, accompanying symptoms, additional diseases, and treatment. We investigated data obtained using standardized pain, depression, and anxiety questionnaires. We further analyzed test results and findings obtained in standardized small fiber tests. Results: FMS patients were on average ten years younger at symptom onset, described higher pain intensities requiring frequent change of pharmaceutics, and reported generalized pain compared to SFN. Pain in FMS was accompanied by irritable bowel or sleep disturbances, and in SFN by paresthesias, numbness, and impaired glucose metabolism (P < 0.01 each). Family history was informative for chronic pain and affective disorders in FMS (P < 0.001) and for neurological disorders in SFN patients (P < 0.001). Small fiber pathology in terms of skin denervation and/or thermal sensory threshold elevation was present in 110/158 (69.7 \%) FMS patients and 39/53 (73.6 \%) SFN patients. FMS patients mainly showed proximally reduced skin innervation and higher corneal nerve branch densities (p<0.001) whereas SFN patients were characterized by reduced cold detection and prolonged electrical A-delta conduction latencies (P < 0.05). Conclusions: Our data show that FMS and SFN differ substantially. Detailed pain, drug and family history, investigating blood glucose metabolism, and applying differential small fiber tests may help to improve diagnostic differentiation and targeted therapy.},
  language  = {en}
}
@article{EgenolfAltenschildescheKressetal.2021,
  author    = {Egenolf, Nadine and Altenschildesche, Caren Meyer zu and Kreß, Luisa and Eggermann, Katja and Namer, Barbara and Gross, Franziska and Klitsch, Alexander and Malzacher, Tobias and Kampik, Daniel and Malik, Rayaz A. and Kurth, Ingo and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Diagnosing small fiber neuropathy in clinical practice: a deep phenotyping study},
  series = {Therapeutic Advances in Neurological Disorders},
  volume    = {14},
  journal   = {Therapeutic Advances in Neurological Disorders},
  issn      = {1756-2864},
  doi       = {10.1177/17562864211004318},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232019},
  year      = {2021},
  abstract  = {Background and aims: Small fiber neuropathy (SFN) is increasingly suspected in patients with pain of uncertain origin, and making the diagnosis remains a challenge lacking a diagnostic gold standard. Methods: In this case-control study, we prospectively recruited 86 patients with a medical history and clinical phenotype suggestive of SFN. Patients underwent neurological examination, quantitative sensory testing (QST), and distal and proximal skin punch biopsy, and were tested for pain-associated gene loci. Fifty-five of these patients additionally underwent pain-related evoked potentials (PREP), corneal confocal microscopy (CCM), and a quantitative sudomotor axon reflex test (QSART). Results: Abnormal distal intraepidermal nerve fiber density (IENFD) (60/86, 70\%) and neurological examination (53/86, 62\%) most frequently reflected small fiber disease. Adding CCM and/or PREP further increased the number of patients with small fiber impairment to 47/55 (85\%). Genetic testing revealed potentially pathogenic gene variants in 14/86 (16\%) index patients. QST, QSART, and proximal IENFD were of lower impact. Conclusion: We propose to diagnose SFN primarily based on the results of neurological examination and distal IENFD, with more detailed phenotyping in specialized centers.},
  language  = {en}
}
@phdthesis{Kress2020,
  author    = {Kreß, Luisa Sophia},
  title     = {Determination of cytokine and axon guidance molecule profiles in patients with small fiber neuropathy},
  doi       = {10.25972/OPUS-20911},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-209113},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {The pathophysiological mechanisms of pain in small fiber neuropathy (SFN) are unclear. Based on experimental and clinical studies, sensitized nociceptors in the skin are reported to be involved in pain development. These nociceptors may be sensitized by cutaneous and systemic pain mediators e.g. pro- and anti-inflammatory cytokines. The aim of our study was, to measure the systemic and local gene expression of pro- and anti-inflammatory cytokines in white blood cells (WBC) as well as in primary fibroblasts and keratinocytes obtained from human skin of patients with SFN. Furthermore, gene expression levels of axon guidance molecules and their receptors, as potential regulators of the intraepidermal nerve fiber density (IENFD), were investigated. 55 patients and 31 healthy controls were prospectively recruited. Participants underwent extensive clinical phenotyping and blood sampling, 6-mm skin punch biopsies were taken from the right lateral calf and the upper thigh. Systemic relative gene expression levels (ΔG) of the interleukin (IL)-1β, IL-2, IL-6, IL-8, and tumor necrosis factor (TNF) was measured in WBC. Skin punch biopsies were taken to determine the IENFD and to obtain primary fibroblast and keratinocyte cell cultures. Skin cells were then used for investigation of ΔG in axon guidance molecules netrin 1 (NTN1) and ephrin A4 (EPHA4) as well as their receptors Unc5b receptor, and ephrin A4 (EFNA4) as well as cytokines IL-1β, IL-4, IL-6, IL-8, IL-10, TNF, and transforming growth factor (TGF). Systemically, gene expression of IL-2, IL-8, and TNF was higher in SFN patients compared to healthy controls. In keratinocytes, higher expression levels of NTN1 and TGF were found when comparing the SFN patients to the controls. In fibroblasts higher gene expression was shown in NTN1, Unc5b, IL-6, and IL-8 when comparing patients to healthy controls. The systemically and local elevated levels of pro-inflammatory, algesic cytokines in SFN patients compared to healthy controls, confirms a potential pathophysiological role in the development of neuropathic pain. Data also indicate fibroblasts and keratinocytes to influence subepidermal and intraepidermal nerve fiber growth through the expression of NTN1 and Unc5b. Thus, skin cells may contribute to the development of neuropathic pain through local denervation.},
  subject      = {Neuropathischer Schmerz},
  language  = {en}
}
@article{KressEgenolfSommeretal.2023,
  author    = {Kreß, Luisa and Egenolf, Nadine and Sommer, Claudia and {\"U}{\c{c}}eyler, Nurcan},
  title     = {Cytokine expression profiles in white blood cells of patients with small fiber neuropathy},
  series = {BMC Neuroscience},
  volume    = {24},
  journal   = {BMC Neuroscience},
  number    = {1},
  doi       = {10.1186/s12868-022-00770-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300619},
  year      = {2023},
  abstract  = {Background The role of cytokines in the pathophysiology, diagnosis, and prognosis of small fiber neuropathy (SFN) is incompletely understood. We studied expression profiles of selected pro- and anti-inflammatory cytokines in RNA from white blood cells (WBC) of patients with a medical history and a clinical phenotype suggestive for SFN and compared data with healthy controls. Methods We prospectively recruited 52 patients and 21 age- and sex-matched healthy controls. Study participants were characterized in detail and underwent complete neurological examination. Venous blood was drawn for routine and extended laboratory tests, and for WBC isolation. Systemic RNA expression profiles of the pro-inflammatory cytokines interleukin (IL)-1ß, IL-2, IL-8, tumor necrosis factor-alpha (TNF) and the anti-inflammatory cytokines IL-4, IL-10, transforming growth factor beta-1 (TGF) were analyzed. Protein levels of IL-2, IL-8, and TNF were measured in serum of patients and controls. Receiver operating characteristic (ROC)-curve analysis was used to determine the accuracy of IL-2, IL-8, and TNF in differentiating patients and controls. To compare the potential discriminatory efficacy of single versus combined cytokines, equality of different AUCs was tested. Results WBC gene expression of IL-2, IL-8, and TNF was higher in patients compared to healthy controls (IL-2: p = 0.02; IL-8: p = 0.009; TNF: p = 0.03) and discriminated between the groups (area under the curve (AUC) ≥ 0.68 for each cytokine) with highest diagnostic accuracy reached by combining the three cytokines (AUC = 0.81, sensitivity = 70\%, specificity = 86\%). Subgroup analysis revealed the following differences: IL-8 and TNF gene expression levels were higher in female patients compared to female controls (IL-8: p = 0.01; TNF: p = 0.03). The combination of TNF with IL-2 and TNF with IL-2 and IL-8 discriminated best between the study groups. IL-2 was higher expressed in patients with moderate pain compared to those with severe pain (p = 0.02). Patients with acral pain showed higher IL-10 gene expression compared to patients with generalized pain (p = 0.004). We further found a negative correlation between the relative gene expression of IL-2 and current pain intensity (p = 0.02). Serum protein levels of IL-2, IL-8, and TNF did not differ between patients and controls. Conclusions We identified higher systemic gene expression of IL-2, IL-8, and TNF in SFN patients than in controls, which may be of potential relevance for diagnostics and patient stratification.},
  language  = {en}
}