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Brown adipose tissue (BAT) is an attractive therapeutic target to combat diabetes and obesity due to its ability to increase glucose expenditure. In a genetic rat model (ZDF fa/fa) of type-2 diabetes and obesity, we aimed to investigate glucose utilization of BAT by \(^{18}\)F-FDG PET imaging. Male Zucker diabetic fatty (ZDF) and Male Zucker lean (ZL) control rats were studied at 13 weeks. Three weeks prior to imaging, ZDF rats were randomized into a no-restriction (ZDF-ND) and a mild calorie restriction (ZDF-CR) group. Dynamic \(^{18}\)F-FDG PET using a dedicated small animal PET system was performed under hyperinsulinemic-euglycemic clamp. \(^{18}\)F-FDG PET identified intense inter-scapular BAT glucose uptake in all ZL control rats, while no focally increased \(^{18}\)F-FDG uptake was detected in all ZDF-ND rats. Mild but significant improved BAT tracer uptake was identified after calorie restriction in diabetic rats (ZDF-CR). The weight of BAT tissue and fat deposits were significantly increased in ZDF-CR and ZDF-ND rats as compared to ZL controls, while UCP-1 and mitochondrial concentrations were significantly decreased. Whitening and severely impaired insulin-stimulated glucose uptake in BAT was confirmed in a rat model of type-2 diabetes. Additionally, calorie restriction partially restored the impaired BAT glucose uptake.
Background
Arrhythmogenic cardiomyopathy is an inherited heart muscle disorder leading to ventricular arrhythmias and heart failure, mainly as a result of mutations in cardiac desmosomal genes. Desmosomes are cell-cell junctions mediating adhesion of cardiomyocytes; however, the molecular and cellular mechanisms underlying the disease remain widely unknown. Desmocollin-2 is a desmosomal cadherin serving as an anchor molecule required to reconstitute homeostatic intercellular adhesion with desmoglein-2. Cardiac specific lack of desmoglein-2 leads to severe cardiomyopathy, whereas overexpression does not. In contrast, the corresponding data for desmocollin-2 are incomplete, in particular from the view of protein overexpression. Therefore, we developed a mouse model overexpressing desmocollin-2 to determine its potential contribution to cardiomyopathy and intercellular adhesion pathology.
Methods and results
We generated transgenic mice overexpressing DSC2 in cardiac myocytes. Transgenic mice developed a severe cardiac dysfunction over 5 to 13 weeks as indicated by 2D-echocardiography measurements. Corresponding histology and immunohistochemistry demonstrated fibrosis, necrosis and calcification which were mainly localized in patches near the epi- and endocardium of both ventricles. Expressions of endogenous desmosomal proteins were markedly reduced in fibrotic areas but appear to be unchanged in non-fibrotic areas. Furthermore, gene expression data indicate an early up-regulation of inflammatory and fibrotic remodeling pathways between 2 to 3.5 weeks of age.
Conclusion
Cardiac specific overexpression of desmocollin-2 induces necrosis, acute inflammation and patchy cardiac fibrotic remodeling leading to fulminant biventricular cardiomyopathy.
Background/Aims:
Acute kidney injury (AKI) is a postoperative complication after cardiac surgery with a high impact on mortality and morbidity. Nephrocheck® [TIMP-2*IGFBP7] determines markers of tubular stress, which occurs prior to tubular damage. It is unknown at which time-point [TIMP-2*IGFBP7] measurement should be performed to ideally predict AKI. We investigated the association of [TIMP-2*IGFBP7] at various time-points with the incidence of AKI in patients undergoing elective cardiac surgery including cardio-pulmonary bypass.
Methods: In a prospective cohort study, serial blood and urine samples were collected from 150 patients: pre-operative, at ICU-admission, 24h and 48h post-surgery. AKI was defined as Serum-Creatinine rise >0.3 mg/dl within 48hrs. Urinary [TIMP-2*IGFBP7] was measured at pre-operative, ICU-admission and 24h post-surgery; medical staff was kept blinded to these results.
Results: A total of 35 patients (23.5%) experienced AKI, with a higher incidence in those with high [TIMP-2*IGFBP7] values at ICU admission (57.1% vs. 10.1%, p<0.001). In logistic regression [TIMP-2*IGFBP7] at ICU admission was independently associated with the occurrence of AKI (Odds Ratio 11.83; p<0.001, C-statistic= 0.74) after adjustment for EuroSCORE II and CBP-time.
Conclusions: Early detection of elevated [TIMP-2*IGFBP7] at ICU admission was strongly predictive for postoperative AKI and appeared to be more precise as compared to subsequent measurements.
C-X-C motif chemokine receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer. This study investigated the feasibility of CXCR4-directed imaging with positron emission tomography/computed tomography (PET/CT) using [\(^{68}\)Ga]Pentixafor in malignant pleural mesothelioma.
Six patients with pleural mesothelioma underwent [\(^{68}\)Ga]Pentixafor-PET/CT. 2′-[\(^{18}\)F]fluoro-2′-deoxy-D-glucose ([\(^{18}\)F]FDG)-PET/CT (4/6 patients) and immunohistochemistry obtained from biopsy or surgery (all) served as standards of reference. Additionally, 9 surgical mesothelioma samples were available for histological work-up.
Whereas [\(^{18}\)F]FDG-PET depicted active lesions in all patients, [\(^{68}\)Ga]Pentixafor-PET/CT recorded physiologic tracer distribution and none of the 6 patients presented [\(^{68}\)Ga]Pentixafor-positive lesions. This finding paralleled results of immunohistochemistry which also could not identify relevant CXCR4 surface expression in the samples analyzed.
In contrast to past reports, our data suggest widely absence of CXCR4 expression in pleural mesothelioma. Hence, robust cell surface expression should be confirmed prior to targeting this chemokine receptor for diagnosis and/or therapy.
Zusammenfassend lässt sich festhalten, dass in dieser Arbeit 15 neu entwickelte Substanzen zur selektiven und hochaffinen Blockade der Aldosteronsynthase untersucht werden konnten. Es wurden mehrere neue aufeinander aufbauende Testsysteme etabliert, um die neuen Substanzen auf ihre Selektivität und Affinität gegenüber der Aldosteronsynthase zu untersuchen. Eine Testung der Inhibition der humanen Aldosteronsynthase und der 11β-Hydroxylase zuerst in getrennten Zellkulturansätzen, die die humanen Enzyme stabil exprimieren, und anschließend in der NCI-h295 Zelllinie, die beide Enzyme und zusätzlich die meisten anderen Enzyme der Steroidbiosynthese stabil exprimieren, ist eine gute Voraussetzung, um selektive und hochaffine Aldosteronsynthaseinhibitoren zu finden. Hier konnten sechs Inhibitoren ausgewählt werden, die hochaffin und selektiv an die Aldosteronsynthase binden und diese inhibieren. Die weitere Testung der [18F] markierten Substanzen zeigte für eine Substanz eine hochaffine und selektive Bindung an humanes adrenales Gewebe und keine unspezifische Bindung an andere humane Gewebe. Hier liegt die Voraussetzung vor, den Tracer weiteren in vivo Studien zuzuführen, um am humanisierten Mausmodell zu untersuchen, ob eine Bindung in vivo entsprechend den vielversprechenden Ergebnissen in vitro abläuft. Auch die ex vivo Studie an Nebennieren einer gegenüber der CYP11B2 humanisierten Maus bekräftigte diese Ergebnisse. Mit Hilfe dieser Untersuchungsmethoden lassen sich in Zukunft noch weiter entwickelte Substanzen umfangreich auf ihre Selektivität, Spezifität und Affinität testen. Dies dient als Grundlage für weitere Untersuchungen zur Entwicklung eines PET-Tracers für die Differentialdiagnostik bei primärem Hyperaldosteronismus. Eine Erkrankung, die häufiger ist als vermutet, und bei der die Differentialdiagnostik die entscheidende Voraussetzung für die Einleitung einer Therapie ist, die sich entweder operativ oder medikamentös darstellt. Bisherige differentialdiagnostische Vorgehensweisen beim primären Hyperaldosteronismus bieten aktuell keine zufriedenstellenden Ergebnisse; dies kann sich mit der Einführung eines neuen PET Tracers ändern.
Introduction: The prognosis of medullary thyroid carcinoma (MTC) is poor using common chemotherapeutic approaches. However, during the last years encouraging results of recently introduced tyrosine kinase inhibitors (TKI) such as vandetanib have been published. In this study we aimed to correlate the results of \(^{18}\)F-fluorodeoxyglucose ([\(^{18}\)F]FDG) positron emission tomography (PET) imaging with treatment outcome.
Methods: Eighteen patients after thyroidectomy with recurrent/advanced MTC lesions receiving vandetanib (300 mg orally/day) could be analysed. A baseline \(^{18}\)F-FDG PET prior to and a follow-up \(^{18}\)F-FDG PET 3 months after TKI initiation were performed. During follow-up, tumor progression was assessed every 3 months including computed tomography according to RECIST. Progression-free survival (PFS) was correlated with the maximum standardized uptake value of \(^{18}\)F-FDG in lymph nodes (SUV(LN)max) or visceral metastases (SUV(MTS)max) as well as with clinical parameters using ROC analysis.
Results: Within median 3.6 years of follow-up, 9 patients showed disease progression at median 8.5 months after TKI initiation. An elevated glucose consumption assessed by baseline \(^{18}\)F-FDG PET (SUV(LN)max > 7.25) could predict a shorter PFS (2 y) with an accuracy of 76.5% (SUV(LN)max <7.25, 4.3 y; p=0.03). Accordingly, preserved tumor metabolism in the follow-up PET (SUV(MTS)max >2.7) also demonstrated an unfavorable prognosis (accuracy, 85.7%). On the other hand, none of the clinical parameters reached significance in response prediction.
Conclusions: In patients with advanced and progressive MTC, tumors with higher metabolic activity at baseline are more aggressive and more prone to progression as reflected by a shorter PFS; they should be monitored more closely. Preserved glucose consumption 3 months after treatment initiation was also related to poorer prognosis.
Background
Chronic kidney disease (CKD) is a common comorbid condition in coronary heart disease (CHD). CKD predisposes the patient to acute kidney injury (AKI) during hospitalization. Data on awareness of kidney dysfunction among CHD patients and their treating physicians are lacking. In the current cross-sectional analysis of the German EUROASPIRE IV sample we aimed to investigate the physician’s awareness of kidney disease of patients hospitalized for CHD and also the patient’s awareness of CKD in a study visit following hospital discharge.
Methods
All serum creatinine (SCr) values measured during the hospital stay were used to describe impaired kidney function (eGFR\(_{CKD-EPI}\) < 60 ml/min/1.73m2) at admission, discharge and episodes of AKI (KDIGO definition). Information extracted from hospital discharge letters and correct ICD coding for kidney disease was studied as a surrogate of physician’s awareness of kidney disease. All patients were interrogated 0.5 to 3 years after hospital discharge, whether they had ever been told about kidney disease by a physician.
Results
Of the 536 patients, 32% had evidence for acute or chronic kidney disease during the index hospital stay. Either condition was mentioned in the discharge letter in 22%, and 72% were correctly coded according to ICD-10. At the study visit in the outpatient setting 35% had impaired kidney function. Of 158 patients with kidney disease, 54 (34%) were aware of CKD. Determinants of patient’s awareness were severity of CKD (OR\(_{eGFR}\) 0.94; 95%CI 0.92–0.96), obesity (OR 1.97; 1.07–3.64), history of heart failure (OR 1.99; 1.00–3.97), and mentioning of kidney disease in the index event’s hospital discharge letter (OR 5.51; 2.35–12.9).
Conclusions
Although CKD is frequent in CHD, only one third of patients is aware of this condition. Patient’s awareness was associated with kidney disease being mentioned in the hospital discharge letter. Future studies should examine how raising physician’s awareness for kidney dysfunction may improve patient’s awareness of CKD.
Der Morbus Fabry ist eine X-chromosomal rezessive, lysosomale
Speicherkrankheit, die durch eine Mutation im α - Galactosidase A Gen
verursacht wird. Dadurch werden unter anderem Bestandteile der
Plasmamembran (Globotriaosylceramide) nicht mehr degradiert und sie
akkumulieren intrazellulär. Daraus resultiert, vom anfänglichen
Einzelzellschäden, letzten Endes ein oftmals schwerer Organschaden mit
Funktionsausfällen. Die einzige kausale Therapie besteht in der Substituierung
des betroffenen Enzyms.
Der Morbus Fabry äußert sich klinisch als eine Multisystemerkrankung mit
hauptsächlich renaler, nervaler, sowie kardialer Beteiligung. Vor allem letztere
ist maßgeblich für die verkürzte Lebenserwartung verantwortlich. Die Patienten
entwickeln mit Progression der Erkrankung häufig eine linksventrikuläre
Hypertrophie, eine Herzinsuffizienz und durch die zunehmende Akkumulation
der Globotriaosylceramide entsteht im Verlauf ein fibrotischer Umbau im
Myokard. Dies ist möglicherweise auch der Entstehungsort für maligne
Rhythmusstörungen. Wissenschaftlich erforscht ist, dass supraventikuläre
sowie ventrikuläre Tachykardien bzw. Bradykardien bis hin zu Asystolie/Pausen
bei diesen Patienten auftreten können. Ebenso weiß man, dass man mit Hilfe
von so genannten Event Recordern, die kontinuierlich die elektrische
Herzaktivität überwachen und die Daten via Telemetrie an ein Zentrum senden,
die Detektionsrate von Rhythmusstörungen erhöhen kann.
Aber ob solch ein Event Recorder auch bei Patienten mit fortgeschrittener
Fabry - Kardiomyopathie einen Nutzen hat und sie bei diesen Patienten zur
Detektion von malignen Rhythmusstörungen beitragen ist bisher unklar und
Thema dieser Studie.
Insgesamt implantierte man 16 Patienten (12 Männer / 4 Frauen), mit einem
gesicherten Morbus Fabry, einen Event Recorder. Sie erhielten 7,4 ± 4,5
Jahren die Enzymersatztherapie, wurden über einen Zeitraum von 0,3 - 2
Jahren beobachtet und übertrugen ihre Daten durchschnittlich 14 ± 11 mal pro
Monat. Dabei konnten insgesamt 8547 klinisch relevante Übertragungen aufgezeichnet werden, die entsprechend der Studieneinteilung in Asystolie,
Bradykardie, Vorhofflimmern, und ventrikuläre Tachykardie eingeteilt worden
sind.
Asystolie Episoden, mit elektrischen Pausen von 3,3 bis 4,4 Sekunden, wurden
insgesamt 66-mal bei 4 Patienten mit dem Event Recorder aufgezeichnet.
Über 8000 Bradykardien konnten bei 6 Männern und 1 Frau dokumentiert
werden, darunter ein AV-Block II° Typ Mobitz mit ei ner 2:1 Überleitung.
Fast 370-mal konnte ein intermittierendes Vorhofflimmern bzw. Vorhofflattern,
mit Flimmerzeiten von 10 Sekunden bis maximal 86400 Sekunden, dargestellt
werden. Bei insgesamt 5 Patienten konnten 10 ventrikuläre Tachykardie –
Episoden, mit einer maximalen Herzfrequenz 206 Schlägen / min, durch den
Event Recorder aufgezeichnet werden.
So konnten selbst bei dieser kleinen Kohorte, mit dem Event Recorder, viele
klinisch relevante Herzrhythmusstörungen detektiert werden. Auf Grundlage
dieser Daten sprach man im Verlauf bei den entsprechenden Patienten eine
Empfehlung zur Therapieänderungen aus um klinische Komplikationen zu
verhindern.
Dies führte letzten Endes zu der Schlussfolgerung, dass der Einsatz von Event
Recordern sicherlich ein sehr nützliches diagnostisches Instrument zur
Detektion von malignen Rhythmusstörungen bei Patienten mit einer
fortgeschrittenen Fabry-Kardiomyopathie ist.
Es sollte nun weiter geprüft werden, ob der Event Recorder bereits in früheren
Stadien des Morbus Fabry zum Einsatz kommen sollte.
Background: Faster rates of cognitive decline are likely to result in earlier onset of cognitive impairment and dementia. d-galactose, a derivative of lactose, is used in animal studies to induce neurodegeneration. Milk is the primary source of lactose in the human diet, and its effects on cognitive decline have not been fully evaluated. Objective: Assess the association of milk intake with change in cognitive function over 20 years. Methods: A total of 13,751 participants of the Atherosclerosis Risk in Communities (ARIC) cohort completed a food frequency questionnaire and three neurocognitive evaluations from 1990 through 2013. Two single nucleotide polymorphisms (SNPs) were used to determine lactase persistence (LCT-13910 C/T for Whites and LCT-14010 G/C for Blacks). Mixed-effects models were used to study the association of milk intake with cognitive change. Multiple imputations by chained equations were used to account for attrition. Results: Milk intake greater than 1 glass/day was associated with greater decline in the global z-score over a 20-year period. The difference in decline was 0.10 (95% CI: 0.16, 0.03) z-scores, or an additional 10% decline, relative to the group reporting “almost never” consuming milk. Conclusions: Replication of these results is warranted in diverse populations with greater milk intake and higher variability of lactase persistence genotype.