Inhibiting Hippo pathway kinases releases WWC1 to promote AMPAR-dependent synaptic plasticity and long-term memory in mice

The localization, number, and function of postsynaptic AMPA-type glutamate receptors (AMPARs) are crucial for synaptic plasticity, a cellular correlate for learning and memory. The Hippo pathway member WWC1 is an important component of AMPAR-containing protein complexes. However, the availability of WWC1 is constrained by its interaction with the Hippo pathway kinases LATS1 and LATS2 (LATS1/2). Here, we explored the biochemical regulation of this interaction and found that it is pharmacologically targetable in vivo. In primary hippocampal neurons, phosphorylation of LATS1/2 by the upstream kinases MST1 and MST2 (MST1/2) enhanced the interaction between WWC1 and LATS1/2, which sequestered WWC1. Pharmacologically inhibiting MST1/2 in male mice and in human brain-derived organoids promoted the dissociation of WWC1 from LATS1/2, leading to an increase in WWC1 in AMPAR-containing complexes. MST1/2 inhibition enhanced synaptic transmission in mouse hippocampal brain slices and improved cognition in healthy male mice and in male mouse models of Alzheimer's disease and aging. Thus, compounds that disrupt the interaction between WWC1 and LATS1/2 might be explored for development as cognitive enhancers.

SKA2 regulated hyperactive secretory autophagy drives neuroinflammation-induced neurodegeneration

High levels of proinflammatory cytokines induce neurotoxicity and catalyze inflammation-driven neurodegeneration, but the specific release mechanisms from microglia remain elusive. Here we show that secretory autophagy (SA), a non-lytic modality of autophagy for secretion of vesicular cargo, regulates neuroinflammation-mediated neurodegeneration via SKA2 and FKBP5 signaling. SKA2 inhibits SA-dependent IL-1β release by counteracting FKBP5 function. Hippocampal Ska2 knockdown in male mice hyperactivates SA resulting in neuroinflammation, subsequent neurodegeneration and complete hippocampal atrophy within six weeks. The hyperactivation of SA increases IL-1β release, contributing to an inflammatory feed-forward vicious cycle including NLRP3-inflammasome activation and Gasdermin D-mediated neurotoxicity, which ultimately drives neurodegeneration. Results from protein expression and co-immunoprecipitation analyses of male and female postmortem human brains demonstrate that SA is hyperactivated in Alzheimer's disease. Overall, our findings suggest that SKA2-regulated, hyperactive SA facilitates neuroinflammation and is linked to Alzheimer's disease, providing mechanistic insight into the biology of neuroinflammation.

ADHD Prevalence among Outpatients with Severe Opioid Use Disorder on Daily Intravenous Diamorphine and/or Oral Opioid Maintenance Treatment

(1) Background: Attention deficit hyperactivity disorder (ADHD) is a common comorbid condition in opioid use disorder (OUD) and is associated with a more severe course of substance use. Patients with severe OUD who have not responded to oral opioid maintenance treatment can be treated with intravenous diamorphine up to three times per day. Here, we investigated the prevalence of ADHD among patients undergoing either daily diamorphine maintenance treatment or daily oral opioid maintenance treatment. (2) Methods: We assessed all participants with the WURS-k and the ADHD-SR. The Diagnostic Interview for ADHD in Adults (DIVA) was performed with all participants who met the cut-off in the WURS-k and/or ADHD-SR. (3) Results: The overall prevalence of ADHD was 17.9%. Prevalence of ADHD among patients undergoing daily diamorphine maintenance treatment was 14.3%. Prevalence of ADHD among patients undergoing daily oral opioid maintenance treatment was 20.3%. The combined presentation of ADHD was the most prevalent condition. In urine samples of participants with comorbid ADHD, heroin was detected the most and cocaine the least frequently. (4) Conclusions: Almost one out of five patients with OUD suffered from comorbid ADHD. In 83.3%, ADHD had not been diagnosed prior to participation in this study. Thus, patients with SUD could benefit from being routinely screened for ADHD.

Hippo-released WWC1 facilitates AMPA receptor regulatory complexes for hippocampal learning

Learning and memory rely on changes in postsynaptic glutamergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type receptor (AMPAR) number, spatial organization, and function. The Hippo pathway component WW and C2 domain-containing protein 1 (WWC1) regulates AMPAR surface expression and impacts on memory performance. However, synaptic binding partners of WWC1 and its hierarchical position in AMPAR complexes are largely unclear. Using cell-surface proteomics in hippocampal tissue of Wwc1-deficient mice and by generating a hippocampus-specific interactome, we show that WWC1 is a major regulatory platform in AMPAR signaling networks. Under basal conditions, the Hippo pathway members WWC1 and large tumor-suppressor kinase (LATS) are associated, which might prevent WWC1 effects on synaptic proteins. Reduction of WWC1/LATS binding through a point mutation at WWC1 elevates the abundance of WWC1 in AMPAR complexes and improves hippocampal-dependent learning and memory. Thus, uncoupling of WWC1 from the Hippo pathway to AMPAR-regulatory complexes provides an innovative strategy to enhance synaptic transmission.

Leptin mediates protective effects on the vasculature

Introduction and purpose

Lipodystrophy (LD) syndromes are characterized by the loss of adipose tissue resulting in metabolic complications and accelerated atherosclerosis. The systemic concentration of the adipokine leptin is reduced in LD as a result of adipose tissue deficiency. A therapeutical option to treat LD is the substitution of leptin, which improves metabolic complications and reduces mortality. However, the vascular effects of leptin remain largely unknown.

Here we analyze the direct effects of leptin on the vascular system and the development of atherosclerosis.

Methods and results

Treatment of human endothelial cells (ECs) with leptin reduced endothelial inflammation and the process of endothelial-to-mesenchymal transition (EndMT) (CNN1, −41.4%, p<0.05, n=4). In addition, leptin administration prevented the EndMT-induced increase of endothelial permeability. The protective effect of leptin on EndMT was confirmed in vivo in a combined lipodystrophic and atherosclerosis-prone mouse model (LDLR−/−; aP2-nSrebp1c). Treatment of the mice with leptin (3.0 mg/kg body weight daily for 8 weeks) decreased EndMT. Leptin showed no effect on plaques size but reduced the protrusion of plaques in atherosclerotic areas of the aortic roots (−31%, p<0.05, n=4–6).

Cytokine screening revealed an increase of the growth differentiation factor 15 (GDF15) in serum of LD patients (+26.2%, p<0.05, n=53–58) and in ECs after EndMT (+138%, p<0.05, n=6743–10920). This increase was reversed using leptin treatment in ECs undergoing EndMT, in the LD mice model, and in LD patients after 4 weeks of leptin administration. Indeed, treatment of endothelial cells with GDF15 induced EndMT (CNN1, +7.7-fold-control, p<0.05, n=3), and impaired EC barrier function. Neutralizing antibodies targeting GDF15 inhibited EndMT-mediated expression of mesenchymal genes (CNN1, −54%, p<0.05, n=4). The treatment of ECs with serum from LD patients induced EndMT and the increase of mesenchymal marker expression was inhibited with additional administration with neutralizing antibodies targeting GDF15 (CNN1, −28%, p<0.05, n=3).

Conclusion

Our findings indicate that EndMT is part of the cardiovascular disease progression in lipodystrophy syndromes. Leptin treatment has direct protective vascular effects by preventing inflammation, EndMT, and maintaining endothelial integrity.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)

Microstructured layered targets for improved laser-induced x-ray backlighters

We present the usage of two-layer targets with laser-illuminated front-side microstructures for x-ray backlighter applications. The targets consisted of a silicon front layer and copper back side layer. The structured layer was irradiated by the 500-fs PHELIX laser with an intensity above 10^{20}Wcm^{-2}. The total emission and one-dimensional extent of the copper Kα x-ray emission as well as a wide spectral range between 7.9 and 9.0 keV were recorded with an array of crystal spectrometers. The measurements show that the front-side modifications of the silicon in the form of conical microstructures maintain the same peak brightness of the Kα emission as flat copper foils while suppressing the thermal emission background significantly. The observed Kα source sizes can be influenced by tilting the conical microstructures with respect to the laser axis. Overall, the recorded copper Kα photon yields were in the range of 10^{11}sr^{-1}, demonstrating the suitability of these targets for probing applications without subjecting the probed material to additional heating from thermal line emission.

Myo-Inositol Levels in the Dorsal Hippocampus Serve as Glial Prognostic Marker of Mild Cognitive Impairment in Mice

Dementia is a devastating age-related disorder. Its therapy would largely benefit from the identification of susceptible subjects at early, prodromal stages of the disease. To search for such prognostic markers of cognitive impairment, we studied spatial navigation in male BALBc vs. B6N mice in combination with in vivo magnetic resonance spectroscopy (1H-MRS). BALBc mice consistently showed higher escape latencies than B6N mice, both in the Water Cross Maze (WCM) and the Morris water maze (MWM). These performance deficits coincided with higher levels of myo-inositol (mIns) in the dorsal hippocampus before and after training. Subsequent biochemical analyses of hippocampal specimens by capillary immunodetection and liquid chromatography mass spectrometry-based (LC/MS) metabolomics revealed a higher abundance of glial markers (IBA-1, S100B, and GFAP) as well as distinct alterations in metabolites including a decrease in vitamins (pantothenic acid and nicotinamide), neurotransmitters (acetylcholine), their metabolites (glutamine), and acetyl-L-carnitine. Supplementation of low abundant acetyl-L-carnitine via the drinking water, however, failed to revert the behavioral deficits shown by BALBc mice. Based on our data we suggest (i) BALBc mice as an animal model and (ii) hippocampal mIns levels as a prognostic marker of mild cognitive impairment (MCI), due to (iii) local changes in microglia and astrocyte activity, which may (iv) result in decreased concentrations of promnesic molecules.

Inhalational Anesthetics Do Not Deteriorate Amyloid-β-Derived Pathophysiology in Alzheimer's Disease: Investigations on the Molecular, Neuronal, and Behavioral Level

BACKGROUND

Studies suggest that general anesthetics like isoflurane and sevoflurane may aggravate Alzheimer's disease (AD) neuropathogenesis, e.g., increased amyloid-β (Aβ) protein aggregation resulting in synaptotoxicity and cognitive dysfunction. Other studies showed neuroprotective effects, e.g., with xenon.

OBJECTIVE

In the present study, we want to detail the interactions of inhalational anesthetics with Aβ-derived pathology. We hypothesize xenon-mediated beneficial mechanisms regarding Aβ oligomerization and Aβ-mediated neurotoxicity on processes related to cognition.

METHODS

Oligomerization of Aβ 1-42 in the presence of anesthetics has been analyzed by means of TR-FRET and silver staining. For monitoring changes in neuronal plasticity due to anesthetics and Aβ 1-42, Aβ 1-40, pyroglutamate-modified amyloid-(AβpE3), and nitrated Aβ (3NTyrAβ), we quantified long-term potentiation (LTP) and spine density. We analyzed network activity in the hippocampus via voltage-sensitive dye imaging (VSDI) and cognitive performance and Aβ plaque burden in transgenic AD mice (ArcAβ) after anesthesia.

RESULTS

Whereas isoflurane and sevoflurane did not affect Aβ 1-42 aggregation, xenon alleviated the propensity for aggregation and partially reversed AβpE3 induced synaptotoxic effects on LTP. Xenon and sevoflurane reversed Aβ 1-42-induced spine density attenuation. In the presence of Aβ 1-40 and AβpE3, anesthetic-induced depression of VSDI-monitored signaling recovered after xenon, but not isoflurane and sevoflurane removal. In slices pretreated with Aβ 1-42 or 3NTyrAβ, activity did not recover after washout. Cognitive performance and plaque burden were unaffected after anesthetizing WT and ArcAβ mice.

CONCLUSION

None of the anesthetics aggravated Aβ-derived AD pathology in vivo. However, Aβ and anesthetics affected neuronal activity in vitro, whereby xenon showed beneficial effects on Aβ 1-42 aggregation, LTP, and spine density.

Analysis of laser-proton acceleration experiments for development of empirical scaling laws

Numerous experiments on laser-driven proton acceleration in the MeV range have been performed with a large variety of laser parameters since its discovery around the year 2000. Both experiments and simulations have revealed that protons are accelerated up to a maximum cut-off energy during this process. Several attempts have been made to find a universal model for laser proton acceleration in the target normal sheath acceleration regime. While these models can qualitatively explain most experimental findings, they can hardly be used as predictive models, for example, for the energy cut-off of accelerated protons, as many of the underlying parameters are often unknown. Here we analyze experiments on laser proton acceleration in which scans of laser and target parameters were performed. We derive empirical scaling laws from these parameter scans and combine them in a scaling law for the proton energy cut-off that incorporates the laser pulse energy, the laser pulse duration, the focal spot radius, and the target thickness. Using these scaling laws, we give examples for predicting the proton energy cut-off and conversion efficiency for state-of-the-art laser systems.

Time-dependent lipid profile inversely associates with mortality in hemodialysis patients - independent of inflammation/malnutrition

BACKGROUND

Patients with end-stage kidney disease have an extremely high cardiovascular mortality rate, but there is a paradoxical relationship between lipid profile and survival in haemodialysis patients. To investigate whether inflammation/malnutrition confounds the associations between lipids and mortality, we studied a full lipid profile comprising of five clinically well-established lipid parameters and its associations with mortality in a large, multinational European cohort with a median follow-up >3 years.

METHODS

The association between quartiles of total, high-density lipoprotein (HDL), non-HDL, low-density lipoprotein (LDL) cholesterol, as well as triglyceride, levels and the end-points of all-cause, cardiovascular and non-cardiovascular mortality was assessed in a cohort of 5,382 incident, adult haemodialysis patients from >250 Fresenius Medical Care dialysis centres out of 14 participating countries using baseline and time-dependent Cox models. Analyses were fully adjusted and stratified for inflammation/malnutrition status and other patient-level variables.

RESULTS

Time-dependent quartiles of total, HDL, non-HDL and LDL cholesterol were inversely associated with the hazard for all-cause, cardiovascular and non-cardiovascular mortality. Compared with the lowest quartile of the respective lipid parameter, hazard ratios of other quartiles were <0.86. Similar, albeit weaker, associations were found with baseline lipid profile and mortality. Neither time-dependent nor baseline associations between lipid profile and mortality were affected by inflammation/malnutrition, statin use or geography.

CONCLUSIONS

Baseline and time-dependent lipid profile are inversely associated with mortality in a large, multicentre cohort of incident haemodialysis patients. Inflammation/malnutrition is not a confounder nor effect modificator of the associations between lipid profile and mortality in European haemodialysis patients.

Spatially resolved online particle detector using scintillators for laser-driven particle sources

Laser-based particle accelerators have been an active field of research for over two decades moving from laser systems capable of one shot every hour to systems able to deliver repetition rates in the Hz regime. Based on the advancements in laser technology, the corresponding detection methods need to develop from single to multiple use with high readout speed. Here, we present an online compact tracker of particles using scintillators with nine resolvable energy levels and a spatial resolution of 3.6 × 3.6 mm² over the whole active area. This paper describes the design and construction of the detector, which is based on pixellated scintillators embedded inside an absorber matrix. The scintillator pixels are fiberoptically coupled to a camera system for online readout and analysis. Calibration with a radioactive source and first experimental data measuring laser accelerated ions at the PHELIX laser at GSI, Darmstadt, Germany, are presented and discussed.

Stress-primed secretory autophagy promotes extracellular BDNF maturation by enhancing MMP9 secretion

The stress response is an essential mechanism for maintaining homeostasis, and its disruption is implicated in several psychiatric disorders. On the cellular level, stress activates, among other mechanisms, autophagy that regulates homeostasis through protein degradation and recycling. Secretory autophagy is a recently described pathway in which autophagosomes fuse with the plasma membrane rather than with lysosomes. Here, we demonstrate that glucocorticoid-mediated stress enhances secretory autophagy via the stress-responsive co-chaperone FK506-binding protein 51. We identify the matrix metalloproteinase 9 (MMP9) as one of the proteins secreted in response to stress. Using cellular assays and in vivo microdialysis, we further find that stress-enhanced MMP9 secretion increases the cleavage of pro-brain-derived neurotrophic factor (proBDNF) to its mature form (mBDNF). BDNF is essential for adult synaptic plasticity and its pathway is associated with major depression and posttraumatic stress disorder. These findings unravel a cellular stress adaptation mechanism that bears the potential of opening avenues for the understanding of the pathophysiology of stress-related disorders.

SARS-CoV-2-mediated dysregulation of metabolism and autophagy uncovers host-targeting antivirals

Viruses manipulate cellular metabolism and macromolecule recycling processes like autophagy. Dysregulated metabolism might lead to excessive inflammatory and autoimmune responses as observed in severe and long COVID-19 patients. Here we show that SARS-CoV-2 modulates cellular metabolism and reduces autophagy. Accordingly, compound-driven induction of autophagy limits SARS-CoV-2 propagation. In detail, SARS-CoV-2-infected cells show accumulation of key metabolites, activation of autophagy inhibitors (AKT1, SKP2) and reduction of proteins responsible for autophagy initiation (AMPK, TSC2, ULK1), membrane nucleation, and phagophore formation (BECN1, VPS34, ATG14), as well as autophagosome-lysosome fusion (BECN1, ATG14 oligomers). Consequently, phagophore-incorporated autophagy markers LC3B-II and P62 accumulate, which we confirm in a hamster model and lung samples of COVID-19 patients. Single-nucleus and single-cell sequencing of patient-derived lung and mucosal samples show differential transcriptional regulation of autophagy and immune genes depending on cell type, disease duration, and SARS-CoV-2 replication levels. Targeting of autophagic pathways by exogenous administration of the polyamines spermidine and spermine, the selective AKT1 inhibitor MK-2206, and the BECN1-stabilizing anthelmintic drug niclosamide inhibit SARS-CoV-2 propagation in vitro with IC50 values of 136.7, 7.67, 0.11, and 0.13 μM, respectively. Autophagy-inducing compounds reduce SARS-CoV-2 propagation in primary human lung cells and intestinal organoids emphasizing their potential as treatment options against COVID-19.

Mineralocorticoid receptors dampen glucocorticoid receptor sensitivity to stress via regulation of FKBP5

Responding to different dynamic levels of stress is critical for mammalian survival. Disruption of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) signaling is proposed to underlie hypothalamic-pituitary-adrenal (HPA) axis dysregulation observed in stress-related psychiatric disorders. In this study, we show that FK506-binding protein 51 (FKBP5) plays a critical role in fine-tuning MR:GR balance in the hippocampus. Biotinylated-oligonucleotide immunoprecipitation in primary hippocampal neurons reveals that MR binding, rather than GR binding, to the Fkbp5 gene regulates FKBP5 expression during baseline activity of glucocorticoids. Notably, FKBP5 and MR exhibit similar hippocampal expression patterns in mice and humans, which are distinct from that of the GR. Pharmacological inhibition and region- and cell type-specific receptor deletion in mice further demonstrate that lack of MR decreases hippocampal Fkbp5 levels and dampens the stress-induced increase in glucocorticoid levels. Overall, our findings demonstrate that MR-dependent changes in baseline Fkbp5 expression modify GR sensitivity to glucocorticoids, providing insight into mechanisms of stress homeostasis.

[Treatment mapping of lower urinary tract symptoms due to benign prostatic hyperplasia-an analysis of the Governing Body of German Prostate Centers]

BACKGROUND

Due to the high incidence and demographic development, there is an urgent need for healthcare research data on lower urinary tract symptoms due to benign prostatic hyperplasia (LTUS/BPH). Since 2005 the Governing Body of German Prostate Centers (DVPZ) has been collecting data from 22 prostate centers in order to determine the quality and type of cross-sectoral care in particular for LUTS/BPH patients.

OBJECTIVES

Presentation of the DVPZ database in general, as well as an investigation of treatment patterns for medical and instrumental therapies.

MATERIALS AND METHODS

The analysis is based on UroCloud data sets from 30 November 2017. In the UroCloud data on diagnostics, therapy and course of disease are recorded in a web-based manner.

RESULTS

A total of 29,555 therapies were documented for 18,299 patients (1.6/patient), divided into 48.5% instrumental, 29.2% medical treatment, and 18.0% "wait and see" (in 4.3% no assignment was possible). Patients treated with an instrumental therapy were oldest (median: 72 years, interquartile range: 66-77), had the largest prostate volumes (50 ml, 35-75 ml), and were mostly bothered by symptoms (International Prostate Symptom Score = 19/4). The majority of patients under medical treatment received alphablockers (56%); phytotherapeutics were used least frequently (3%). Instrumental therapies are dominated by transurethral resection (TUR) of the prostate (60.0%), open prostatectomy (9.4%) and laser therapy (5.0%), with laser therapy having the shortest hospital stay (5 days) and the lowest transfusion and re-intervention rates (1.0% and 4.6%, respectively).

CONCLUSIONS

The DVPZ certificate covers the complete spectrum of cross-sectoral care for LUTS/BPH patients and documents the use of the various therapies as well as their application and effectiveness in the daily routine setting.

Circulating Pro-Neurotensin in gestational diabetes mellitus

BACKGROUND AND AIMS

Pro-Neurotensin (NT), a stable surrogate parameter of NT, has recently been introduced as a peptide predicting the development of obesity, diabetes mellitus, cardiovascular diseases, and cardiovascular mortality. However, regulation of Pro-NT in gestational diabetes mellitus (GDM) remains uninvestigated.

METHODS AND RESULTS

Pro-NT was quantified in 74 women with GDM, 74 healthy, gestational age-matched, pregnant controls, as well as in a second cohort comprising of 74 healthy, non-pregnant control women, using a chemiluminometric sandwich immunoassay. Pro-NT was correlated to measures of obesity, hypertension, glucose and lipid metabolism, renal function, and inflammation. Mean ± standard deviation of circulating Pro-NT levels were not significantly different in women with GDM (100.2 ± 75.7 pmol/l) as compared to healthy, pregnant controls (103.2 ± 37.4 pmol/l) and healthy, non-pregnant female controls (105.9 ± 38.9 pmol/l) (p = 0.661). Homeostasis model assessment of insulin resistance (HOMA-IR) and creatinine positively correlated with serum Pro-NT in multivariate regression analysis. In contrast, free fatty acids (FFA) were inversely correlated with circulating Pro-NT. Results sustained adjustment for pregnancy status.

CONCLUSIONS

Circulating Pro-NT is not independently associated with GDM, but is with HOMA-IR, creatinine, and FFA even after adjustment for pregnancy status.

The brown-fat-secreted adipokine neuregulin 4 is decreased in gestational diabetes mellitus

AIMS

Neuregulin 4 has recently been recognized as a novel adipokine secreted by brown adipose tissue (BAT), with beneficial effects on murine insulin resistance and hepatic steatosis. Yet, thus far, neither regulation of neuregulin 4 in gestational diabetes mellitus (GDM) nor its longitudinal changes in the peripartum period have been elucidated.

METHODS

Circulating neuregulin 4 levels were measured by ELISA in 74 women with GDM and 74 healthy, gestational-age-matched controls. Also, neuregulin 4 was quantified during pregnancy and compared with postpartum levels in a follow-up study of 25 women with previous GDM and 25 healthy control women.

RESULTS

Women with GDM had lower median serum levels of the novel BAT-secreted adipokine neuregulin 4 (3.0μg/L) compared with healthy (non-GDM) pregnant controls (3.5μg/L; P=0.020), and the area under the glucose curve (AUC_Glucose) was an independent and negative predictor of circulating neuregulin 4 (P=0.033). Also, median postpartum serum concentrations of neuregulin 4 (3.2μg/L) were not significantly different from prepartum levels (2.8μg/L; P=0.328). In addition, neuregulin 4 was positively and independently associated with irisin (P=0.009), but not other BAT-secreted adipokines.

CONCLUSION/INTERPRETATION

Women with GDM have significantly lower circulating neuregulin 4 levels compared with healthy pregnant controls, and the AUC_Glucose is negatively and independently associated with neuregulin 4 during pregnancy. Neuregulin 4 is positively correlated with irisin during pregnancy, as well as in a longitudinal fashion. Future studies are now needed to better elucidate the precise pathomechanisms of the regulation of BAT-secreted adipokines during pregnancy.

Multiple polymerization – formation of hybrid materials consisting of two or more polymers from one monomer

The synthesis of hybrid materials consisting of three different components from only one monomer is reported for the first time.

German MedicalTeachingNetwork (MDN) implementing national standards for teacher training

BACKGROUND

An increasing demand for proof of professionalism in higher education strives for quality assurance (QA) and improvement in medical education. A wide range of teacher trainings is available to medical staff in Germany. Cross-institutional approval of individual certificates is usually a difficult and time consuming task for institutions. In case of non-acceptance it may hinder medical teachers in their professional mobility.

AIM

The faculties of medicine aimed to develop a comprehensive national framework, to promote standards for formal faculty development programmes across institutions and to foster professionalization of medical teaching.

METHODS AND RESULTS

Addressing the above challenges in a joint approach, the faculties set up the national MedicalTeacherNetwork (MDN). Great importance is attributed to work out nationally concerted standards for faculty development and an agreed-upon quality control process across Germany. Medical teachers benefit from these advantages due to portability of faculty development credentials from one faculty of medicine to another within the MDN system.

CONCLUSION

The report outlines the process of setting up the MDN and the national faculty development programme in Germany. Success factors, strengths and limitations are discussed from an institutional, individual and general perspective. Faculties engaged in similar developments might be encouraged to transfer the MDN concept to their countries.

Circulating angiopoietin-like protein 8 is independently associated with fasting plasma glucose and type 2 diabetes mellitus

OBJECTIVE

Angiopoietin-like protein 8 (Angptl8) has recently been introduced as a novel adipokine/hepatokine that promotes pancreatic β-cell proliferation and improves glucose tolerance in mouse models of insulin resistance. However, regulation of Angptl8 in human type 2 diabetes mellitus (T2DM) and renal dysfunction has not been determined.

RESEARCH DESIGN AND METHODS

Serum Angptl8 levels were quantified by ELISA in 62 patients with T2DM as compared with 58 nondiabetic subjects in vivo. Within both groups, about half of the patients were on chronic hemodialysis or had an estimated glomerular filtration rate above 50 mL/min/1.73 m(2). Furthermore, we investigated the effect of insulin and differentiation on Angptl8 mRNA expression in 3T3-L1 adipocytes in vitro.

RESULTS

Median [interquartile range] serum Angptl8 levels were higher in patients with T2DM (1.19 [0.37] μg/L) as compared with nondiabetic subjects (1.03 [0.47] μg/L) (P = .005). Furthermore, the adipokine/hepatokine was significantly higher in women (1.21 [0.47] μg/L) as compared with men (1.05 [0.44] μg/L]) (P = .013). In multivariate analysis, fasting glucose and T2DM but not renal function remained independent and positive predictors of circulating Angptl8 even after adjustment for markers of obesity, lipid status, and inflammation (P < .05). Furthermore, Angptl8 mRNA expression was induced by insulin and during adipogenesis in 3T3-L1 adipocytes in vitro.

CONCLUSIONS

Circulating Angptl8 is positively and independently associated with T2DM and fasting glucose in vivo. Furthermore, Angptl8 mRNA expression is induced by insulin and during adipogenesis in 3T3-L1 adipocytes in vitro.

Circulating adipocyte fatty acid binding protein is increased in chronic and acute renal dysfunction

BACKGROUND AND AIMS

The adipokine adipocyte fatty acid binding protein (AFABP) is positively associated with the development of the metabolic syndrome, diabetes mellitus, and cardiovascular disease. We hypothesized that AFABP also increases with deteriorating renal function.

METHODS AND RESULTS

Serum AFABP levels were quantified by enzyme linked immunosorbent assay in 532 patients with chronic kidney disease (CKD) covering the whole spectrum of estimated glomerular filtration rate (eGFR) categories from G1 to G5 (study population 1). Furthermore, AFABP was measured in 32 patients before and within 30 h after elective unilateral nephrectomy, a model of acute kidney dysfunction (AKD) (study population 2). Moreover, circulating AFABP was investigated in rats undergoing bilateral nephrectomy (BNE) as compared to sham-operated animals. Median serum AFABP levels adjusted for age, gender, and body mass index significantly increased with increasing eGFR category (G1: 22.0 μg/l; G2: 34.6 μg/l; G3: 56.7 μg/l; G4: 95.2 μg/l; and G5: 173.9 μg/l). Furthermore, renal dysfunction remained positively associated with AFABP in multivariate analysis in this cohort. In patients undergoing unilateral nephrectomy, AFABP increased significantly after surgery (42.1 μg/l) as compared to pre-surgical values (29.3 μg/l). Furthermore, relative changes of post-to-pre-surgical AFABP levels were independently associated with relative changes of post-to-pre-surgical creatinine concentrations. After BNE in rats, AFABP increased significantly as compared to sham-operated animals.

CONCLUSIONS

We show that AFABP is significantly elevated in CKD and AKD patients. Furthermore, measures of renal function are associated with circulating AFABP. Moreover, animal experiments indicate that AFABP levels strongly depend on renal function.

Relationship between serum levels of angiopoietin-related growth factor and metabolic risk factors

Angiopoietin-related growth factor (AGF, also known as angiopoietin-like protein 6) has been introduced as a novel hepatocyte-derived factor, which antagonizes obesity and insulin resistance in mice. However, human studies show conflicting results and are limited to a small cohort of patients. In the current study, we therefore sought to investigate AGF serum levels in a large metabolically well-characterized cohort. AGF serum concentrations were determined by commercial enzyme-linked immunosorbent assay in 697 patients of a cohort from Eastern Germany (Sorbs). Correlations of AGF serum levels with clinical and biochemical measures of glucose and lipid metabolism, as well as markers of renal function, were investigated. In nondiabetic subjects (n=627), AGF was positively correlated with markers of insulin resistance and negatively correlated with high-density lipoprotein cholesterol in univariate analyses (p<0.05). After adjustment for age, gender, and body mass index, none of these factors remained independently associated with AGF, neither in nondiabetic subjects nor in patients with type 2 diabetes mellitus (T2DM) (n=70). However, we confirmed existing data of significantly higher AGF concentrations in patients with T2DM as compared to controls in this large cohort. Circulating AGF is elevated in subjects with T2DM and related to the type of antidiabetic treatment, but is not independently associated with anthropometric parameters, indices of insulin sensitivity and secretion, or a number of other adipokines.

Serum levels of fractalkine are associated with markers of insulin resistance in gestational diabetes

AIMS

Fractalkine has recently been introduced as an adipokine that improves glucose tolerance. Regulation of fractalkine in gestational diabetes, as well as its association with markers of obesity, glucose and lipid metabolism, inflammation and renal function, has not been elucidated.

METHODS

Circulating fractalkine was quantified by enzyme-linked immunosorbent assay in 74 women with gestational diabetes and 74 healthy, pregnant control subjects matched for age, BMI, and gestational age.

RESULTS

Median (interquartile range) levels of fractalkine were not significantly different between the two groups [gestational diabetes: 2.24 (2.16) μg/l; control: 2.45 (1.38) μg/l] (P = 0.461). In multivariate linear regression analysis, fractalkine remained independently associated with homeostasis model assessment of insulin resistance (β = -0.253, P = 0.002) and the proinflammatory adipokine progranulin (β = 0.218, P = 0.007).

CONCLUSIONS

Circulating fractalkine is not different between women with gestational diabetes and control subjects, but the adipokine is independently associated with markers of insulin resistance and proinflammatory progranulin in pregnancy.

Different associations of adipokines in lean and healthy adults

Regulation of adipokines in lean adults without metabolic disease and without eating disorders has not been comprehensively elucidated. We hypothesized that some of the established associations of these adipocyte-secreted proteins with anthropometric and biochemical measures of glucose homeostasis, lipid metabolism, renal function, as well as inflammation, differ in healthy and low weight adults as compared to overweight/obese patients. Eighty-one subjects with a body mass-index below 22.0 kg/m2 and without malnutrition or eating disorders, as well as fifty overweight/obese patients, were recruited for the study. Serum concentrations of seven adipokines (adiponectin, leptin, adipocyte fatty acid-binding protein [AFABP], chemerin, fibroblast growth factor [FGF]-21, resistin, retinol-binding protein [RBP]-4) were measured by enzyme-linked immunosorbent assays. Lean probands had significantly higher levels of adiponectin and resistin, as well as lower levels of leptin, AFABP, and RBP-4, as compared to overweight/obese subjects. Serum concentrations of adiponectin, leptin, AFABP, chemerin, and resistin were significantly higher in lean women as compared to men (p<0.05). In lean subjects, fasting insulin independently predicted leptin and resistin concentrations. Furthermore, C-reactive protein was independently associated with circulating AFABP and chemerin. Moreover, lean body mass was an independent predictor of leptin, fat mass predicted AFABP levels, whereas RBP-4 was independently correlated to age and triglycerides. In addition, high density lipoprotein cholesterol predicted AFABP. Our results support the notion that several of these adipokines are regulated in a different manner in lean adults as compared to overweight/obese subjects and patients with eating disorders.

Adipocyte fatty acid-binding protein is released from adipocytes by a non-conventional mechanism

Adipocyte fatty acid-binding protein (AFABP) is an adipokine, which induces insulin resistance. However, AFABP does not possess any secretion-directed signals and the mechanisms for AFABP release have not been thoroughly assessed so far. In the current study, mechanisms for AFABP secretion were elucidated in 3T3-L1 adipocytes in vitro in the presence or absence of hormonal stimulation, calcium ionophore and secretion inhibitors by cell fractionation experiments, immunoblotting and ELISAs. We demonstrate that AFABP secretion is upregulated during adipocyte differentiation. AFABP secretion is not influenced by treatment with protein secretion inhibitors that block vesicular traffic at the endoplasmic reticulum and the Golgi apparatus. AFABP is secreted partially by adipocyte-derived microvesicles (ADMs), an established mechanism for unconventional secretion from adipocytes. Both total and ADM-secreted AFABP are downregulated by insulin and upregulated by the calcium ionophore ionomycin. Furthermore, murine RAW 264.7 macrophages secrete AFABP and AFABP release from these cells is upregulated by lipopolysaccharide treatment. Taken together, these results suggest that AFABP is actively released by unconventional mechanisms and by ADMs from 3T3-L1 adipocytes. Furthermore, AFABP secretion from fat cells is regulated by insulin and intracellular calcium.

Development of a rat central venous catheter model for evaluation of vaccines to prevent Staphylococcus epidermidis and Staphylococcus aureus early biofilms

Indwelling central venous catheters are a common and important source of nosocomial Staphylococcus epidermidis and S. aureus infections, causing increased morbidity and mortality during hospitalization. A model was developed to reflect the clinical situation of catheter colonization by transient hematogeneously spread staphylococci, in order to investigate potential vaccine candidates. Rats were cannulated in the right jugular vein, followed by challenge through the tail vein with either S. epidermidis RP62a, or S. aureus Becker. At 24 hr post challenge, colonizing bacteria were found to be present on the catheter in an early biofilm, as evidenced by the presence of polysaccharide intercellular adhesin (PIA). For vaccination studies, rats were first immunized, surgically cannulated, and then challenged via the tail vein. At 24 hr post challenge, the catheters were harvested and cultured on mannitol salt agar plates. The catheters were scored as positive if there was outgrowth of bacterial colonies, and negative if no colonies were observed. A S. epidermidis antigen (SERP0630, MenD), and a S. aureus antigen (SACOL1138, iron regulated surface determinant B, IsdB) were found to have significant protective activity in this model, compared to mock immunized controls. Using SERP0630 as the test immunogen, it was also determined that a single vaccination of rats after cannulation was sufficient for significant catheter protection. This model may be used to evaluate antigens for protective activity against transient hematogenous spread of staphylococci resulting in catheter colonization and early biofilm formation.

A fully human monoclonal antibody to Staphylococcus aureus iron regulated surface determinant B (IsdB) with functional activity in vitro and in vivo

A fully human monoclonal antibody (CS-D7, IgG1) specific for the iron regulated surface determinant B (IsdB) of Staphylococcus aureus was isolated from the Cambridge Antibody Technology (CAT) scFv antibody library. As compared to previously described IsdB specific murine monoclonals, CS-D7 has a unique, non-overlapping binding site on IsdB, and exhibits increased in vivo activity. The antibody recognizes a conformational epitope spanning amino acids 50 to 285 and has a binding affinity of 340 (± 75) pM for IsdB. CS-D7 bound to a wide variety of S. aureus strains, but not to an isdB deletion mutant. The antibody mediated opsonophagocytic (OP) killing in vitro and mediated significant protection in vivo. In a murine lethal sepsis model, the antibody conferred protection from death when dosed prior to challenge, but not when dosed after challenge. Importantly, in a central venous catheter (CVC) model in rats, the antibody reduced bacteremia and prevented colonization of indwelling catheters. Protection was observed when rats were dosed with CS-D7 prior to challenge as well as post challenge. IsdB is currently being investigated for clinical efficacy against S. aureus infection, and the activity of this human IsdB specific antibody supplements the growing body of evidence to support targeting this antigen for vaccine development.

[Analyses of the role of immunocytology in the differential diagnosis of patients with asymptomatic microhematuria]

INTRODUCTION

Discriminating between malignant and nonmalignant conditions remains a challenge in the evaluation of patients with asymptomatic microhematuria. In this prospective study the role of immunocytology in the assessment microhematuria was studied.

MATERIAL AND METHODS

uCyt is a commercially available immunocytological assay based on microscopical detection of tumor-associated antigens in urothelial cells by immunofluorescence. Between September 2000 and December 2006, 222 consecutive patients with newly diagnosed painless microhematuria without prior transitional cell carcinoma were included. All urine samples were examined cytologically and immunocytologically. A total of 211 samples (95%) were assessable.

RESULTS

Clinical examination by physical examination, cystoscopy, laboratory tests, and imaging yielded bladder cancer in ten cases (4%). Further diagnoses were BPH (27%), cystitis (including IC) (12%), urolithiasis (9%), urethral or ureteral strictures (6%), papilloma (2%), and"further conditions" (16%). In 52 patients (23%) reasons for hematuria were not identified. Immunocytology was positive in 8 of 10 bladder tumors (80%) and negative in 178 patients with non-tumor-related hematuria (89%).

CONCLUSIONS

The high sensitivity and good specificity of immunocytology is comparable with that reported in the literature despite a very low disease prevalence in this population. If assessment of these patients would have only been based on immunocytology, 180 costly and invasive diagnostic procedures would have been saved, with only 29 individuals (14%) undergoing these examinations unnecessarily. The authors conclude that these findings justify further investigation of this issue.