Publications by authors named "Andreas L Birkenfeld"

139 Publications

Improving insulin sensitivity, liver steatosis and fibrosis in type 2 diabetes by a food-based digital education-assisted lifestyle intervention program: a feasibility study.

Eur J Nutr 2021 Apr 11. Epub 2021 Apr 11.

Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany.

Purpose: Recent trials demonstrated remission of type 2 diabetes and non-alcoholic fatty liver disease (NAFLD) following formula diet-induced weight loss. To improve the outreach for populations in need, many mobile health apps targeting weight loss have been developed with limited scientific evaluation of these apps. The present feasibility study investigated the effects of a novel approach incorporating a regular 'whole food-based' low-calorie diet combined with app-based digital education and behavioral change program on glucose metabolism and disease management.

Methods: Twenty-four individuals with type 2 diabetes followed this approach supported by weekly coaching calls for 12 weeks. Phenotyping included bioimpedance analysis, mixed-meal tolerance test, magnetic resonance spectroscopy and transient elastography for assessing liver fat content and liver stiffness.

Results: Over 12 weeks, participants reduced their body weight by 9% (97 ± 13 to 88 ± 12 kg), body mass index (BMI; 33 ± 5 to 29 ± 4 kg/m), total fat mass (31 ± 10 to 27 ± 10%) (all p < 0.01) and liver fat by 50% alongside with decreased liver stiffness. Target HbA1c (< 6.5%) was achieved by 38% and resolution of NAFLD (liver fat content < 5.6%) was observed in 30% of the participants.

Conclusion: This novel approach combining digital education with a low-calorie diet results in effective improvements of body weight, glycemic control and NAFLD and could complement existing care for patients with type 2 diabetes.

Trial Registration: NCT04509245.
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http://dx.doi.org/10.1007/s00394-021-02521-3DOI Listing
April 2021

Pancreatic fat cells of humans with type 2 diabetes display reduced adipogenic and lipolytic activity.

Am J Physiol Cell Physiol 2021 Mar 31. Epub 2021 Mar 31.

German Center for Diabetes Research (DZD e.V.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the Eberhard-KarlsUniversity of Tübingen, Neuherberg; Department of Internal Medicine IV, Division of Endocrinology, Diabetology and Nephrology, University Hospital of Eberhard-Karls-University Tübingen, Tübingen, Germany.

Obesity, especially visceral fat accumulation, increases the risk of type 2 diabetes (T2D). The purpose of this study was to investigate the impact of T2D on the pancreatic fat depot. Pancreatic fat pads from 17 partial pancreatectomized patients (PPP) were collected, pancreatic preadipocytes isolated and in vitro differentiated. Patients were grouped using HbA1c into normal glucose tolerant (NGT), prediabetic (PD) and T2D. Transcriptome profiles of preadipocytes and adipocytes were assessed by RNAseq. Insulin sensitivity was estimated by quantifying AKT phosphorylation on western blots. Lipogenic capacity was assessed with oil red O staining, lipolytic activity via fatty acid release. Secreted factors were measured using ELISA. Comparative transcriptome analysis of preadipocytes and adipocytes indicates defective upregulation of genes governing adipogenesis (NR1H3), lipogenesis (FASN, SCD, ELOVL6, FADS1) and lipolysis (LIPE) during differentiation of cells from T2D-PPP. In addition, the ratio of leptin/adiponectin mRNA was higher in T2D than in NGT-PPP. Preadipocytes and adipocytes of NGT-PPP were more insulin sensitive than T2D-PPP cells in regard to AKT phosphorylation. Triglyceride accumulation was similar in NGT and T2D adipocytes. Despite a high expression of the receptors NPR1 and NPR2 in NGT and T2D adipocytes, lipolysis was stimulated by ANP 1.74-fold in NGT cells only. This stimulation was further increased by the PDE5 inhibitor dipyridamole (3.09-fold). Dipyridamole and forskolin increased lipolysis receptor-independently 1.88-fold and 1.48-fold, respectively, solely in NGT cells. In conclusion, the metabolic status persistently affects differentiation and lipolysis of pancreatic adipocytes. These alterations could aggravate the development of T2D.
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http://dx.doi.org/10.1152/ajpcell.00595.2020DOI Listing
March 2021

The hepatokine fetuin-A disrupts functional maturation of pancreatic beta cells.

Diabetologia 2021 Mar 25. Epub 2021 Mar 25.

Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the Eberhard Karls University of Tuebingen (IDM), Tuebingen, Germany.

Aims/hypothesis: Neonatal beta cells carry out a programme of postnatal functional maturation to achieve full glucose responsiveness. A partial loss of the mature phenotype of adult beta cells may contribute to a reduction of functional beta cell mass and accelerate the onset of type 2 diabetes. We previously found that fetuin-A, a hepatokine increasingly secreted by the fatty liver and a determinant of type 2 diabetes, inhibits glucose-stimulated insulin secretion (GSIS) of human islets. Since fetuin-A is a ubiquitous fetal glycoprotein that declines peripartum, we examined here whether fetuin-A interferes with the functional maturity of beta cells.

Methods: The effects of fetuin-A were assessed during in vitro maturation of porcine neonatal islet cell clusters (NICCs) and in adult human islets. Expression alterations were examined via microarray, RNA sequencing and reverse transcription quantitative real-time PCR (qRT-PCR), proteins were analysed by western blotting and immunostaining, and insulin secretion was quantified in static incubations.

Results: NICC maturation was accompanied by the gain of glucose-responsive insulin secretion (twofold stimulation), backed up by mRNA upregulation of genes governing beta cell identity and function, such as NEUROD1, UCN3, ABCC8 and CASR (Log fold change [LogFC] > 1.6). An active TGFβ receptor (TGFBR)-SMAD2/3 pathway facilitates NICC maturation, since the TGFBR inhibitor SB431542 counteracted the upregulation of aforementioned genes and de-repressed ALDOB, a gene disallowed in mature beta cells. In fetuin-A-treated NICCs, upregulation of beta cell markers and the onset of glucose responsiveness were suppressed. Concomitantly, SMAD2/3 phosphorylation was inhibited. Transcriptome analysis confirmed inhibitory effects of fetuin-A and SB431542 on TGFβ-1- and SMAD2/3-regulated transcription. However, contrary to SB431542 and regardless of cMYC upregulation, fetuin-A inhibited beta cell proliferation (0.27 ± 0.08% vs 1.0  ± 0.1% Ki67-positive cells in control NICCs). This effect was sustained by reduced expression (LogFC ≤ -2.4) of FOXM1, CENPA, CDK1 or TOP2A. In agreement, the number of insulin-positive cells was lower in fetuin-A-treated NICCs than in control NICCs (14.4 ± 1.2% and 22.3 ± 1.1%, respectively). In adult human islets fetuin-A abolished glucose responsiveness, i.e. 1.7- and 1.1-fold change over 2.8 mmol/l glucose in control- and fetuin-A-cultured islets, respectively. In addition, fetuin-A reduced SMAD2/3 phosphorylation and suppressed expression of proliferative genes. Of note, in non-diabetic humans, plasma fetuin-A was negatively correlated (p = 0.013) with islet beta cell area.

Conclusions/interpretation: Our results suggest that the perinatal decline of fetuin-A relieves TGFBR signalling in islets, a process that facilitates functional maturation of neonatal beta cells. Functional maturity remains revocable in later life, and the occurrence of a metabolically unhealthy milieu, such as liver steatosis and elevated plasma fetuin-A, can impair both function and adaptive proliferation of beta cells.

Data Availability: The RNAseq datasets and computer code produced in this study are available in the Gene Expression Omnibus (GEO): GSE144950; https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE144950.
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http://dx.doi.org/10.1007/s00125-021-05435-1DOI Listing
March 2021

Renal effects of the serine protease inhibitor aprotinin in healthy conscious mice.

Acta Pharmacol Sin 2021 Mar 23. Epub 2021 Mar 23.

Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Tübingen, Germany.

Treatment with aprotinin, a broad-spectrum serine protease inhibitor with a molecular weight of 6512 Da, was associated with acute kidney injury, which was one of the reasons for withdrawal from the market in 2007. Inhibition of renal serine proteases regulating the epithelial sodium channel ENaC could be a possible mechanism. Herein, we studied the effect of aprotinin in wild-type 129S1/SvImJ mice on sodium handling, tubular function, and integrity under a control and low-salt diet. Mice were studied in metabolic cages, and aprotinin was delivered by subcutaneously implanted sustained release pellets (2 mg/day over 10 days). Mean urinary aprotinin concentration ranged between 642 ± 135 (day 2) and 127 ± 16 (day 8) µg/mL . Aprotinin caused impaired sodium preservation under a low-salt diet while stimulating excessive hyperaldosteronism and unexpectedly, proteolytic activation of ENaC. Aprotinin inhibited proximal tubular function leading to glucosuria and proteinuria. Plasma urea and cystatin C concentration increased significantly under aprotinin treatment. Kidney tissues from aprotinin-treated mice showed accumulation of intracellular aprotinin and expression of the kidney injury molecule 1 (KIM-1). In electron microscopy, electron-dense deposits were observed. There was no evidence for kidney injury in mice treated with a lower aprotinin dose (0.5 mg/day). In conclusion, high doses of aprotinin exert nephrotoxic effects by accumulation in the tubular system of healthy mice, leading to inhibition of proximal tubular function and counterregulatory stimulation of ENaC-mediated sodium transport.
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http://dx.doi.org/10.1038/s41401-021-00628-1DOI Listing
March 2021

The Case | A 74-year-old liver transplant recipient with nephrotic-range proteinuria.

Kidney Int 2021 04;99(4):1031-1032

Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, University Hospital Tübingen, Tübingen, Germany; Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD) at the University Tübingen, Tübingen, Germany.

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http://dx.doi.org/10.1016/j.kint.2020.10.029DOI Listing
April 2021

Low-density lipoprotein cholesterol is associated with insulin secretion.

J Clin Endocrinol Metab 2021 Mar 10. Epub 2021 Mar 10.

Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.

Objective: Pharmacological lowering of LDL cholesterol potently reduces cardiovascular risk while concurrently increasing type 2 diabetes risk. The aim of this study was to investigate the relationship between LDL cholesterol concentrations and insulin secretion and glucagon levels.

Methods: 3,039 subjects without cholesterol lowering therapy, but with increased risk for diabetes, underwent routine blood tests and a 5-point oral glucose tolerance test (OGTT). Glucagon concentrations, insulin secretion and insulin clearance indices were derived from the OGTT.

Results: There was no association between LDL cholesterol and fasting glucagon (p=0.7, ß=-0.01) or post glucose load glucagon levels (p=0.7, ß=-0.07), but we detected significant positive associations of LDL cholesterol and C-peptide-based indices of insulin secretion (AUCC-Peptide(0-30min)/AUCGlucose(0-30min): p=0.0001, ß=0.06; AUCC-Peptide(0-120min)/AUCGlucose(0-120min): p<0.0001, ß=-0.08). In contrast we found a negative association of insulin-based insulin secretion indices with LDL concentrations (Insulinogenic index: p=0.014, ß=-0.04; disposition index: p=0.0005, ß=-0.06). Though, LDL cholesterol levels were positively associated with insulin clearance assessed from C-peptide and insulin concentrations, both in the fasting state and post glucose load (p<0.0001, ß=0.09 and p<0.0001, ß=0.06, respectively).

Conclusion: As C-peptide based indices reflect insulin secretion independent of hepatic clearance, our results indicate lower insulin secretion in case of lesser LDL cholesterol. This could explain deteriorating glycemic control in response to cholesterol lowering drugs.
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http://dx.doi.org/10.1210/clinem/dgab147DOI Listing
March 2021

Lifestyle intervention improves prothrombotic coagulation profile in individuals at high-risk for type 2 diabetes.

J Clin Endocrinol Metab 2021 Feb 28. Epub 2021 Feb 28.

Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen, Germany.

Aims: Patients with obesity and insulin resistance are at higher risk for arterial and venous thrombosis due to a prothrombotic state. If this is reversible by lifestyle intervention was addressed in the current study and potential underlying associations were elucidated.

Subjects And Methods: One-hundred individuals with impaired glucose tolerance or impaired fasting plasma glucose participated in a 1-year lifestyle intervention, including precise metabolic phenotyping and MRT-based determination of liver fat content as well as a comprehensive analysis of coagulation parameters before and after this intervention.

Results: During the lifestyle intervention significant reductions in coagulation factor activities (II, VII, VIII, IX, XI and XII) were observed. Accordingly, prothrombin time (PT%) and activated partial thromboplastin time (aPTT) were slightly decreased and prolonged, respectively. Moreover, PAI-1, vWF and also protein C and protein S decreased. Fibrinogen, antithrombin, D-Dimer and FXIII remained unchanged. Searching for potential regulators, especially weight loss, but also liver fat reduction, improved insulin sensitivity and decreased low-grade inflammation were linked to favorable changes in hemostasis parameters.

Independent Of Weight Loss: , liver fat reduction (FII, protein C, protein S, PAI-1, vWF), improved insulin sensitivity (protein S, PAI-1) and reduced low-grade inflammation (PT%, aPTT, FVIII/IX/XI/XII, vWF) were identified as single potential regulators.

Conclusions: Lifestyle intervention is able to improve a prothrombotic state in individuals at high-risk for type 2 diabetes. Besides body weight, liver fat content, insulin sensitivity and systemic low-grade inflammation are potential mechanisms for improvements in hemostasis and could represent future therapeutic targets.
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http://dx.doi.org/10.1210/clinem/dgab124DOI Listing
February 2021

Zymogen-locked mutant prostasin (Prss8) leads to incomplete proteolytic activation of the epithelial sodium channel (ENaC) and severely compromises triamterene tolerance in mice.

Acta Physiol (Oxf) 2021 Mar 1:e13640. Epub 2021 Mar 1.

Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, University Hospital Tübingen, Tuebingen, Germany.

Aim: The serine protease prostasin (Prss8) is expressed in the distal tubule and stimulates proteolytic activation of the epithelial sodium channel (ENaC) in co-expression experiments in vitro. The aim of this study was to explore the role of prostasin in proteolytic ENaC activation in the kidney in vivo.

Methods: We used genetically modified knockin mice carrying a Prss8 mutation abolishing proteolytic activity (Prss8-S238A) or a mutation leading to a zymogen-locked state (Prss8-R44Q). Mice were challenged with low sodium diet and diuretics. Regulation of ENaC activity by Prss8-S238A and Prss8-R44Q was studied in vitro using the Xenopus laevis oocyte expression system.

Results: Co-expression of murine ENaC with Prss8-wt or Prss8-S238A in oocytes caused maximal proteolytic ENaC activation, whereas ENaC was activated only partially in oocytes co-expressing Prss8-R44Q. This was paralleled by a reduced proteolytic activity at the cell surface of Prss8-R44Q expressing oocytes. Sodium conservation under low sodium diet was preserved in Prss8-S238A and Prss8-R44Q mice but with higher plasma aldosterone concentrations in Prss8-R44Q mice. Treatment with the ENaC inhibitor triamterene over four days was tolerated in Prss8-wt and Prss8-S238A mice, whereas Prss8-R44Q mice developed salt wasting and severe weight loss associated with hyperkalemia and acidosis consistent with impaired ENaC function and renal failure.

Conclusion: Unlike proteolytically inactive Prss8-S238A, zymogen-locked Prss8-R44Q produces incomplete proteolytic ENaC activation in vitro and causes a severe renal phenotype in mice treated with the ENaC inhibitor triamterene. This indicates that Prss8 plays a role in proteolytic ENaC activation and renal function independent of its proteolytic activity.
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http://dx.doi.org/10.1111/apha.13640DOI Listing
March 2021

Low-fat hypocaloric diet reduces neprilysin in overweight and obese human subjects.

ESC Heart Fail 2021 Apr 27;8(2):938-942. Epub 2021 Feb 27.

Section of Metabolic and Vascular Medicine, Medical Clinic III, University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany.

Aims: Neprilysin (NEP), a zinc metallopeptidase, degrades a variety of bioactive peptides including natriuretic peptides terminating their biological action on arterial blood pressure and natriuresis. Pharmacological inhibition of NEP reduces mortality in patients with heart failure with reduced ejection fraction. Physiological interventions reducing NEP levels are unknown in humans. Because obesity leads to increased NEP levels and increases the risk for heart failure, we hypothesized that weight loss reduces NEP concentrations in plasma and tissue.

Methods And Results: We randomized overweight to obese human subjects to a low-fat or low-carbohydrate hypocaloric 6 month weight loss intervention. Soluble NEP was determined in plasma, and NEP mRNA was analysed from subcutaneous adipose tissue before and after diet. Low-fat diet-induced weight loss reduced soluble NEP levels from 0.83 ± 0.18 to 0.72 ± 0.18 μg/L (P = 0.038), while subcutaneous adipose tissue NEP mRNA expression was reduced by both dietary interventions [21% (P = 0.0057) by low-fat diet and 16% (P = 0.048) by low-carbohydrate diet]. We also analysed the polymorphisms of the gene coding for NEP, rs9827586 and rs701109, known to be associated with plasma NEP levels. For both single-nucleotide polymorphisms, minor allele carriers (A/A) had higher baseline plasma NEP levels (rs9827586: β = 0.53 ± 0.23, P < 0.0001; rs701109: β = 0.43 ± 0.22, P = 0.0016), and minor allele carriers of rs9827586 responded to weight loss with a larger NEP reduction (rs9827586: P = 0.0048).

Conclusions: Our study identifies weight loss via a hypocaloric low-fat diet as the first physiological intervention in humans to reduce NEP in plasma and adipose tissue. Specific single-nucleotide polymorphisms further contribute to the decrease. Our findings may help to explain the beneficial effect of weight loss on cardiac function in patients with heart failure.
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http://dx.doi.org/10.1002/ehf2.13220DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8006681PMC
April 2021

The longevity gene mIndy (I'm Not Dead, Yet) affects blood pressure through sympathoadrenal mechanisms.

JCI Insight 2021 Jan 25;6(2). Epub 2021 Jan 25.

Section of Metabolic and Vascular Medicine, Medical Clinic III, University Hospital and Medical Faculty Carl Gustav Carus and.

Reduced expression of the plasma membrane citrate transporter INDY (acronym I'm Not Dead, Yet) extends life span in lower organisms. Deletion of the mammalian Indy (mIndy) gene in rodents improves metabolism via mechanisms akin to caloric restriction, known to lower blood pressure (BP) by sympathoadrenal inhibition. We hypothesized that mIndy deletion attenuates sympathoadrenal support of BP. Continuous arterial BP and heart rate (HR) were reduced in mINDY-KO mice. Concomitantly, urinary catecholamine content was lower, and the decreases in BP and HR by mIndy deletion were attenuated after autonomic ganglionic blockade. Catecholamine biosynthesis pathways were reduced in mINDY-KO adrenals using unbiased microarray analysis. Citrate, the main mINDY substrate, increased catecholamine content in pheochromocytoma cells, while pharmacological inhibition of citrate uptake blunted the effect. Our data suggest that deletion of mIndy reduces sympathoadrenal support of BP and HR by attenuating catecholamine biosynthesis. Deletion of mIndy recapitulates beneficial cardiovascular and metabolic responses to caloric restriction, making it an attractive therapeutic target.
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http://dx.doi.org/10.1172/jci.insight.136083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7934862PMC
January 2021

Global pandemics interconnected - obesity, impaired metabolic health and COVID-19.

Nat Rev Endocrinol 2021 03 21;17(3):135-149. Epub 2021 Jan 21.

German Center for Diabetes Research (DZD), Neuherberg, Germany.

Obesity and impaired metabolic health are established risk factors for the non-communicable diseases (NCDs) type 2 diabetes mellitus, cardiovascular disease, neurodegenerative diseases, cancer and nonalcoholic fatty liver disease, otherwise known as metabolic associated fatty liver disease (MAFLD). With the worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), obesity and impaired metabolic health also emerged as important determinants of severe coronavirus disease 2019 (COVID-19). Furthermore, novel findings indicate that specifically visceral obesity and characteristics of impaired metabolic health such as hyperglycaemia, hypertension and subclinical inflammation are associated with a high risk of severe COVID-19. In this Review, we highlight how obesity and impaired metabolic health increase complications and mortality in COVID-19. We also summarize the consequences of SARS-CoV-2 infection for organ function and risk of NCDs. In addition, we discuss data indicating that the COVID-19 pandemic could have serious consequences for the obesity epidemic. As obesity and impaired metabolic health are both accelerators and consequences of severe COVID-19, and might adversely influence the efficacy of COVID-19 vaccines, we propose strategies for the prevention and treatment of obesity and impaired metabolic health on a clinical and population level, particularly while the COVID-19 pandemic is present.
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http://dx.doi.org/10.1038/s41574-020-00462-1DOI Listing
March 2021

Durable Effects of iGlarLixi Up to 52 Weeks in Type 2 Diabetes: The LixiLan-G Extension Study.

Diabetes Care 2021 Mar 19;44(3):774-780. Epub 2021 Jan 19.

MedStar Health Research Institute, Hyattsville, MD.

Objective: In the LixiLan-G trial, switching to iGlarLixi, a once-daily titratable fixed-ratio combination of insulin glargine 100 units/mL and the glucagon-like peptide 1 receptor agonist (GLP-1 RA) lixisenatide, improved glucose control in type 2 diabetes uncontrolled with GLP-1 RAs over 26 weeks versus continuing prior GLP-1 RA. A prespecified, 26-week, single-arm extension of LixiLan-G aimed to determine the durability of iGlarLixi efficacy and safety over 52 weeks.

Research Design And Methods: Participants with type 2 diabetes uncontrolled by GLP-1 RAs (glycated hemoglobin [HbA] 7-9% [53-75 mmol/mol]) were initially randomized to switch to iGlarLixi or continue prior GLP-1 RA. Those randomized to iGlarLixi who completed the 26-week primary end point period could continue iGlarLixi open-label treatment over a 26-week extension to assess durability of efficacy and safety.

Results: Glycemic control achieved with iGlarLixi at week 26 (mean HbA 6.7% [50 mmol/mol]) was maintained at week 52 (mean HbA 6.7% [50 mmol/mol]; mean ± SD change from baseline at week 52: -1.0 ± 0.9% [11 ± 10 mmol/mol]). Proportions of participants reaching HbA <7% (53 mmol/mol) with iGlarLixi were similar at week 26 (62%) and 52 (64%), as were those reaching this target without documented symptomatic (<3.0 mmol/L) hypoglycemia (57% and 58%). Safety of iGlarLixi was similar at weeks 26 and 52, with low rates of documented symptomatic hypoglycemia and gastrointestinal events.

Conclusions: The efficacy and safety of iGlarLixi at the end of the 26-week randomized treatment period was maintained over the 26-week extension period in the LixiLan-G trial.
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http://dx.doi.org/10.2337/dc20-2023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7896258PMC
March 2021

Pathophysiology-based subphenotyping of individuals at elevated risk for type 2 diabetes.

Nat Med 2021 01 4;27(1):49-57. Epub 2021 Jan 4.

Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.

The state of intermediate hyperglycemia is indicative of elevated risk of developing type 2 diabetes. However, the current definition of prediabetes neither reflects subphenotypes of pathophysiology of type 2 diabetes nor is predictive of future metabolic trajectories. We used partitioning on variables derived from oral glucose tolerance tests, MRI-measured body fat distribution, liver fat content and genetic risk in a cohort of extensively phenotyped individuals who are at increased risk for type 2 diabetes to identify six distinct clusters of subphenotypes. Three of the identified subphenotypes have increased glycemia (clusters 3, 5 and 6), but only individuals in clusters 5 and 3 have imminent diabetes risks. By contrast, those in cluster 6 have moderate risk of type 2 diabetes, but an increased risk of kidney disease and all-cause mortality. Findings were replicated in an independent cohort using simple anthropomorphic and glycemic constructs. This proof-of-concept study demonstrates that pathophysiological heterogeneity exists before diagnosis of type 2 diabetes and highlights a group of individuals who have an increased risk of complications without rapid progression to overt type 2 diabetes.
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http://dx.doi.org/10.1038/s41591-020-1116-9DOI Listing
January 2021

Reduced insulin clearance is linked to subclinical atherosclerosis in individuals at risk for type 2 diabetes mellitus.

Sci Rep 2020 12 31;10(1):22453. Epub 2020 Dec 31.

Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany.

Hyperglycemia and insulin resistance contribute to vascular damage and are regulated by different pathophysiological processes. The aim of the study was to systematically investigate the relative contributions of multiple fasting state- and oral glucose tolerance test (oGTT)-derived glycemic traits to carotid intima-media thickness (cIMT), a surrogate parameter of subclinical atherosclerosis, in individuals with increased risk for type 2 diabetes mellitus (T2D). 667 volunteers (417 women and 250 men, mean age 44.1 years), who were free of cardiovascular disease (CVD), were included in this cross-sectional study. Glucose tolerance, insulin sensitivity, insulin secretion and insulin clearance were assessed by frequently sampled 75 g oGTT. CIMT was measured by high-resolution ultrasound. Insulin clearance was associated with cIMT in univariate analysis (ß = - 0.17, p < 0.0001) and in a stepwise regression analysis on 15 variables possibly affecting cIMT, age (r = 0.3923, p < 0.0001), insulin clearance (r = 0.4564, p < 0.0001), systolic blood pressure (r = 0.4733, p < 0.0001), body mass index (BMI) (r = 0.4804, p = 0.002), gender (r = 0.4831, p = 0.013), and fasting insulin clearance (r = 0.4857, p = 0.030) turned out to be significant determinants of cIMT. In a cross-validated model resulting from this analysis, insulin clearance was found to be an independent determinant of cIMT (ß = - 0.16, p < 0.0001) even after adjusting for traditional CVD risk factors. Reduced insulin clearance may be an early marker of damage on the vasculature, independent of classical CVD risk factors. Reduced insulin clearance should be considered with regard to vascular insulin resistance.
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http://dx.doi.org/10.1038/s41598-020-80581-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7775444PMC
December 2020

Dapagliflozin effects on haematocrit, red blood cell count and reticulocytes in insulin-treated patients with type 2 diabetes.

Sci Rep 2020 12 28;10(1):22396. Epub 2020 Dec 28.

German Centre for Diabetes Research (DZD e.V.), Neuherberg, Germany.

Recent studies have shown that high-risk patients with type 2 diabetes mellitus (T2DM) treated with sodium glucose cotransporter 2 (SGLT2) inhibitors have improved cardiovascular (CV) outcomes. In an exploratory analysis of data from the EMPA-REG study, elevations in haematocrit were shown to be strongly associated with beneficial CV effects. As insulin treatment has been shown to be antinatriuretic, with an associated increase in extracellular fluid volume, it is important to confirm whether haematocrit increase is maintained with concomitant insulin therapy. Here, we investigate the effect of the SGLT2 inhibitor dapagliflozin on haematocrit, red blood cell (RBC) counts and reticulocyte levels in high-risk patients with T2DM receiving insulin. A 24-week, double-blinded, randomised, placebo-controlled trial (ClinicalTrials.gov: NCT00673231) was reported previously with extension periods of 24 and 56 weeks (total of 104 weeks). Patients receiving insulin were randomised 1:1:1:1 to placebo or dapagliflozin at 2.5, 5 or 10 mg. Haematocrit, RBC and reticulocyte measurements were conducted during this study, and a longitudinal repeated-measures analysis was performed here to examine change from baseline during treatment. Dapagliflozin treatment in combination with insulin resulted in a dose-dependent increase in haematocrit levels and RBCs over a 104 week period. There was a short-term increase in reticulocyte levels at the start of treatment, which dropped to below baseline after 8 weeks. SGLT2 inhibition with dapagliflozin leads to a sustained increase in haematocrit in patients receiving chronic insulin treatment.
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http://dx.doi.org/10.1038/s41598-020-78734-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769973PMC
December 2020

Elevated Circulating Glutamate Is Associated With Subclinical Atherosclerosis Independently of Established Risk Markers: A Cross-Sectional Study.

J Clin Endocrinol Metab 2021 Jan;106(2):e982-e989

Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich, Tübingen, Germany.

Objective: Elevated plasma glutamate levels are associated with an increased risk of cardiovascular disease (CVD). Because plasma glutamate levels are also strongly associated with visceral adiposity, nonalcoholic fatty liver disease, insulin resistance, and high circulating levels of branched-chain amino acids (BCAAs), it is unknown to what extent elevated circulating glutamate is an independent marker of an increased risk of atherosclerosis.

Methods: Plasma levels of glutamate and BCAAs were measured in 102 individuals who were precisely phenotyped for body fat mass and distribution (magnetic resonance [MR] tomography), liver fat content (1H-MR spectroscopy), insulin sensitivity (oral glucose tolerance test and hyperinsulinemic, euglycemic clamp [N = 57]), and carotid intima media thickness (cIMT).

Results: Plasma glutamate levels, adjusted for age, sex, body fat mass, and visceral fat mass, correlated positively with liver fat content and cIMT (all std β ≥ .22, all P ≤ .023) and negatively with insulin sensitivity (std β ≤ -.31, P ≤ .002). Glutamate levels also were associated with cIMT, independently of additional adjustment for liver fat content, insulin sensitivity and BCAAs levels (std β ≥ .24, P ≤ .02). Furthermore, an independent positive association of glutamate and interleukin-6 (IL-6) levels was observed (N = 50; std β = .39, P = .03). Although glutamate, adjusted for age, sex, body fat mass, and visceral fat mass, also correlated positively with cIMT in this subgroup (std β = .31, P = .02), after additional adjustment for the parameters liver fat content, insulin sensitivity, BCAAs, or IL-6 levels, adjustment for IL-6 most strongly attenuated this relationship (std β = .28, P = .05).

Conclusions: Elevated plasma glutamate levels are associated with increased cIMT, independently of established CVD risk factors, and this relationship may in part be explained by IL-6-associated subclinical inflammation.
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http://dx.doi.org/10.1210/clinem/dgaa898DOI Listing
January 2021

Overhydration Measured by Bioimpedance Spectroscopy and Urinary Serine Protease Activity Are Risk Factors for Progression of Chronic Kidney Disease.

Kidney Blood Press Res 2020 2;45(6):955-968. Epub 2020 Dec 2.

Department of Internal Medicine IV, Division of Diabetology, Endocrinology and Nephrology, University Hospital Tübingen, Tübingen, Germany.

Background: Overhydration (OH) is common in chronic kidney disease (CKD) and might be related to the excretion of urinary serine proteases. Progression of CKD is associated with proteinuria; however, the interrelations of urinary serine proteases, OH, and progression of CKD remain unclear.

Methods: In n = 179 patients with stable nondialysis-dependent CKD of all stages, OH was measured using bioimpedance spectroscopy (Body Composition Monitor; Fresenius), and urinary serine protease activity was determined using the peptide substrate S-2302. After a median follow-up of 5.9 (IQR: 3.9-6.5) years, progression to end-stage renal disease (ESRD) was analyzed retrospectively.

Results: OH correlated with baseline MDRD-eGFR, urinary albumin creatinine ratio (ACR), and urinary aprotinin-sensitive serine protease activity. Progression to ESRD occurred in n = 33 patients (19%) and correlated with OH and urinary serine protease activity as well as MDRD-eGFR and ACR. Patients were divided into 2 groups determined by cutoff values from receiver operating characteristics for MDRD-eGFR (32 mL/min/1.73 m2), ACR (43 mg/g creatinine), urinary serine protease activity (0.9 RU/g creatinine), and OH (1 L/1.73 m2). Across these cutoff values, Kaplan-Meier curves for renal survival showed significant separations of the groups. In Cox regression adjusted for MDRD-eGFR, ACR, P-NT-pro-BNP, systolic blood pressure, and diabetes mellitus, patients with OH >1 L/1.73 m2 had a 3.32 (95% CI: 1.26-8.76)-fold higher risk for progression to ESRD.

Conclusions: Our results corroborate that OH detected by bioimpedance spectroscopy in CKD patients is an independent risk factor for progression to ESRD in addition to GFR and albuminuria. Urinary serine protease activity is associated with OH and progression of CKD and provides a possible underlying mechanism.
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http://dx.doi.org/10.1159/000510649DOI Listing
December 2020

No modulation of postprandial metabolism by transcutaneous auricular vagus nerve stimulation: a cross-over study in 15 healthy men.

Sci Rep 2020 11 24;10(1):20466. Epub 2020 Nov 24.

Department of Internal Medicine IV, Division of Diabetology, Endocrinology and Nephrology, University Hospital Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany.

Experimental evidence suggests a crucial role of the autonomic nervous system in whole body metabolism with major regulatory effects of the parasympathetic branch in postprandial adaptation. However, the relative contribution of this mechanism is still not fully clear in humans. We therefore compared the effects of transcutaneous auricular vagus nerve stimulation (taVNS, Cerbomed Nemos) with sham stimulation during an oral glucose tolerance test in a randomized, single-blind, cross-over design in 15 healthy lean men. Stimulation was performed for 150 min, 30 min before and during the entire oral glucose tolerance test with stimulation cycles of 30 s of on-phase and 30 s of off-phase and a 25 Hz impulse. Heart rate variability and plasma catecholamine levels were assessed as proxies of autonomic tone in the periphery. Neither analyzed heart rate variability parameters nor plasma catecholamine levels were significantly different between the two conditions. Plasma glucose, insulin sensitivity and insulin secretion were also comparable between conditions. Thus, the applied taVNS device or protocol was unable to achieve significant effects on autonomic innervation in peripheral organs. Accordingly, glucose metabolism remained unaltered. Therefore, alternative approaches are necessary to investigate the importance of the autonomic nervous system in postprandial human metabolism.
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http://dx.doi.org/10.1038/s41598-020-77430-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7686306PMC
November 2020

Increased Expressions of Matrix Metalloproteinases (MMPs) in Prostate Cancer Tissues of Men with Type 2 Diabetes.

Biomedicines 2020 Nov 16;8(11). Epub 2020 Nov 16.

Department of Internal Medicine IV, Division of Diabetology, Endocrinology and Nephrology, University Hospital Tübingen, 72076 Tübingen, Germany.

Type 2 diabetes (T2D) is associated with worse prognosis of prostate cancer (PCa). The molecular mechanisms behind this association are still not fully understood. The aim of this study was to identify key factors, which contribute to the more aggressive PCa phenotype in patients with concurrent T2D. Therefore, we investigated benign and PCa tissue of PCa patients with and without diabetes using real time qPCR. Compared to patients without diabetes, patients with T2D showed a decreased E-cadherin/N-cadherin (CDH1/CDH2) ratio in prostate tissue, indicating a switch of epithelial-mesenchymal transition (EMT), which is a pivotal process in carcinogenesis. In addition, the gene expression levels of matrix metalloproteinases () and CC chemokine ligands () were higher in prostate samples of T2D patients. Next, prostate adenocarcinoma PC3 cells were treated with increasing glucose concentrations to replicate hyperglycemia in vitro. In these cells, high glucose induced expressions of and , which showed significant positive associations with the proliferation marker proliferating cell nuclear antigen (). These results indicate that in prostate tissue of men with T2D, hyperglycemia may induce EMT, increase and gene expressions, which in turn activate invasion and inflammatory processes accelerating the progression of PCa.
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http://dx.doi.org/10.3390/biomedicines8110507DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7696165PMC
November 2020

Characterization of Hormone-Dependent Pathways in Six Human Prostate-Cancer Cell Lines: A Gene-Expression Study.

Genes (Basel) 2020 Oct 7;11(10). Epub 2020 Oct 7.

Department of Internal Medicine IV, Division of Diabetology, Endocrinology, and Nephrology, University Hospital Tübingen, 72076 Tübingen, Germany.

Prostate cancer (PCa), the most incident cancer in men, is tightly regulated by endocrine signals. A number of different PCa cell lines are commonly used for in vitro experiments, but these are of diverse origin, and have very different cell-proliferation rates and hormone-response capacities. By analyzing the gene-expression pattern of main hormone pathways, we systematically compared six PCa cell lines and parental primary cells. We compared these cell lines (i) with each other and (ii) with PCa tissue samples from 11 patients. We found major differences in the gene-expression levels of androgen, insulin, estrogen, and oxysterol signaling between PCa tissue and cell lines, and between different cell lines. Our systematic characterization gives researchers a solid basis to choose the appropriate PCa cell model for the hormone pathway of interest.
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http://dx.doi.org/10.3390/genes11101174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7599530PMC
October 2020

Investigating obesity-associated brain inflammation using quantitative water content mapping.

J Neuroendocrinol 2020 12 6;32(12):e12907. Epub 2020 Oct 6.

Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.

There is growing evidence that obesity is associated with inflammation in the brain, which could contribute to the pathogenesis of obesity. In humans, it is challenging to detect brain inflammation in vivo. Recently, quantitative magnetic resonance imaging (qMRI) has emerged as a tool for characterising pathophysiological processes in the brain with reliable and reproducible measures. Proton density imaging provides quantitative assessment of the brain water content, which is affected in different pathologies, including inflammation. We enrolled 115 normal weight, overweight and obese men and women (body mass index [BMI] range 20.1-39.7 kg m , age range 20-75 years, 60% men) to acquire cerebral water content mapping in vivo using MRI at 3 Tesla. We investigated potential associations between brain water content with anthropometric measures of obesity, body fat distribution and whole-body metabolism. No global changes in water content were associated with obesity. However, higher water content values in the cerebellum, limbic lobe and sub-lobular region were detected in participants with higher BMI, independent of age. More specifically, the dorsal striatum, hypothalamus, thalamus, fornix, anterior limb of the internal capsule and posterior thalamic radiation showed the strongest relationship with BMI, independent of age. In a subgroup with available measurements (n = 50), we identified visceral adipose tissue to be the strongest tested link between higher water content values and obesity. Individuals with metabolic syndrome had the highest water content values in the hypothalamus and the fornix. There is accumulating evidence that inflammation of the hypothalamus contributed to obesity-associated insulin resistance in that area. Whether brain inflammation is a cause or consequence of obesity in humans still needs to be investigated using a longitudinal study design. Using qMRI, we were able to detect marked water content changes in young and older obese adults, which is most likely the result of chronic low-grade inflammation.
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http://dx.doi.org/10.1111/jne.12907DOI Listing
December 2020

FFA2-, but not FFA3-agonists inhibit GSIS of human pseudoislets: a comparative study with mouse islets and rat INS-1E cells.

Sci Rep 2020 10 5;10(1):16497. Epub 2020 Oct 5.

German Centre for Diabetes Research (DZD e.V.), Neuherberg, Germany.

The expression of short chain fatty acid receptors FFA2 and FFA3 in pancreatic islets raised interest in using them as drug targets for treating hyperglycemia in humans. This study aims to examine the efficacy of synthetic FFA2- and FFA3-ligands to modulate glucose-stimulated insulin secretion (GSIS) in human pseudoislets which display intact glucose responsiveness. The FFA2-agonists 4-CMTB and TUG-1375 inhibited GSIS, an effect reversed by the FFA2-antagonist CATPB. GSIS itself was not augmented by CATPB. The FFA3-agonists FHQC and 1-MCPC did not affect GSIS in human pseudoislets. For further drug evaluation we used mouse islets. The CATPB-sensitive inhibitory effect of 100 µM 4-CMTB on GSIS was recapitulated. The inhibition was partially sensitive to the G-protein inhibitor pertussis toxin. A previously described FFA2-dependent increase of GSIS was observed with lower concentrations of 4-CMTB (10 and 30 µM). The stimulatory effect of 4-CMTB on secretion was prevented by the Gq-protein inhibitor FR900359. As in human pseudoislets, in mouse islets relative mRNA levels were FFAR2 > FFAR3 and FFA3-agonists did not affect GSIS. The FFA3-agonists, however, inhibited GSIS in a pertussis toxin-sensitive manner in INS-1E cells and this correlated with relative mRNA levels of Ffar3 > > Ffar2. Thus, in humans, when FFA2-activation impedes GSIS, FFA2-antagonism may reduce glycemia.
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http://dx.doi.org/10.1038/s41598-020-73467-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7536384PMC
October 2020

Considering Insulin Secretory Capacity as Measured by a Fasting C-Peptide/Glucose Ratio in Selecting Glucose-Lowering Medications.

Exp Clin Endocrinol Diabetes 2020 Sep 18. Epub 2020 Sep 18.

German Center for Diabetes Research (DZD), Neuherberg.

Type 2 diabetes mellitus is a heterogeneous disease. Recently introduced new subclassifications promise more efficacious, tailored treatments which could complement current guidelines. In the differentiation of the new diabetes subphenotypes, assessment of insulin secretion is one of the essential components. Based on a large number of insulin secretion measurements, we propose fasting C-peptide/glucose ratio (CGR) as an adequate and practicable estimate of insulin secretion. CGR discriminates insulin deficiency from insulin hypersecretion. We suggest using insulin secretion, determined from CGR, as an essential input for therapeutic decisions at the beginning or modification of diabetes treatment. Furthermore, we propose 3 practical steps to guide decisions in the subtype-specific therapy of diabetes mellitus. The first step consists of detecting insulin deficiency indicated by a low CGR with the need for immediate insulin therapy. The second step is related to high CGR and aims at lowering cardiovascular risk associated with diabetes. The third step is the consideration of a de-escalation of glucose-lowering therapy in individuals with mild diabetes subphenotypes.
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http://dx.doi.org/10.1055/a-1242-9809DOI Listing
September 2020

Transcript Levels of Aldo-Keto Reductase Family 1 Subfamily C (AKR1C) Are Increased in Prostate Tissue of Patients with Type 2 Diabetes.

J Pers Med 2020 Sep 12;10(3). Epub 2020 Sep 12.

Department of Internal Medicine IV, Division of Endocrinology, Diabetology and Nephrology, University Hospital Tübingen, 72076 Tübingen, Germany.

Aldo-keto reductase family 1 (AKR1) enzymes play a crucial role in diabetic complications. Since type 2 diabetes (T2D) is associated with cancer progression, we investigated the impact of diabetes on gene expression in the context of prostate cancer (PCa) development. In this study, we analyzed benign (BEN) prostate and PCa tissue of patients with and without T2D. Furthermore, to replicate hyperglycemia in vitro, we treated the prostate adenocarcinoma cell line PC3 with increasing glucose concentrations. Gene expression was quantified using real-time qPCR. In the prostate tissue of patients with T2D, and transcripts were higher compared to samples of patients without diabetes. In PC3 cells, high glucose treatment induced the gene expression levels of , and . Furthermore, both in human tissue and in PC3 cells, the transcript levels of and showed positive associations with oncogenes, which are involved in proliferation processes and HIF1α and NFκB pathways. These results indicate that in the prostate glands of patients with T2D, hyperglycemia could play a pivotal role by inducing the expression of and . The higher transcript level of was furthermore associated with upregulated HIF1α and NFκB pathways, which are major drivers of PCa carcinogenesis.
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http://dx.doi.org/10.3390/jpm10030124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564141PMC
September 2020

Proteasuria in nephrotic syndrome-quantification and proteomic profiling.

J Proteomics 2021 01 12;230:103981. Epub 2020 Sep 12.

Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, University Hospital Tübingen, Germany; Institute of Diabetes Research and Metabolic Diseases (IDM), Helmholtz Center Munich, University Tübingen, Germany; German Center for Diabetes Research (DZD), University Tübingen, Germany. Electronic address:

Nephrotic syndrome is characterized by urinary excretion of plasma proteases or proteasuria. There is a lack of data on the quantity, activity status and identity of these aberrantly filtered proteases. We established a fluorescence-based substrate assay to quantify protease activity in urine samples from healthy and nephrotic humans and mice. Protease class activity was determined after addition of specific inhibitors. Individual proteases were identified by tandem mass spectrometry (MS/MS). In spot urine samples from 10 patients with acute nephrotic syndrome of various etiology, urinary protease activity was significantly increased compared to that of healthy persons (753 ± 178 vs. 244 ± 65 relative units, p < 0.05). The corresponding proteases were highly sensitive to inhibition by the serine protease inhibitors AEBSF (reduction by 85 ± 6% and 72 ± 8%, respectively) and aprotinin (83 ± 9% vs. 25 ± 6%, p < 0.05). MS/MS of all urinary proteins or after AEBSF purification showed that most of them were active serine proteases from the coagulation and complement cascade. These findings were recapitulated in mice, pointing to a similar pathophysiology. In conclusion, nephrotic syndrome leads to increased urinary excretion of active plasma proteases which can be termed proteasuria. Serine proteases account for the vast majority of urinary protease activity in health and nephrotic syndrome. SIGNIFICANCE STATEMENT: In this study, we found that nephrotic urine samples of humans and mice have a significantly increased protease activity compared to healthy urine samples, using a universal pentapeptide substrate library. This was driven by increased excretion of aprotinin-sensitive serine proteases. With tandem mass spectrometry, we provide a comprehensive and systematic overview of all urinary proteases or the "urine proteasome". We identified renally expressed proteases in health and addition of proteases from the coagulation and complement cascade in the nephrotic state. These results set the basis to study the role of urinary proteases at both health and nephrotic syndrome to find diagnostic markers of renal disease as well as possible therapeutic targets.
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http://dx.doi.org/10.1016/j.jprot.2020.103981DOI Listing
January 2021

The TUDID Study - Background and Design of a Prospective Cohort.

Exp Clin Endocrinol Diabetes 2020 Sep 10. Epub 2020 Sep 10.

Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.

Prevalence of both type 1 and type 2 diabetes mellitus is growing worldwide and one major cause for morbidity and mortality. However, not every patient develops diabetes-related complications, but causes for the individual susceptibility are still not fully understood. As a platform to address this, we initiated the TUDID (TUebingen DIabetes Database) study, a prospective, monocentric, observational study that includes adults with diabetes mellitus who are treated in the inpatient clinic of a University Hospital in southern Germany. Besides a thorough clinical examination and extensive laboratory tests (with integrated biobanking), major study focuses are the kidneys, the eyes, the vasculature as well as cognition and mood where standardized investigations for early stages for diabetes complications are performed. Analyses of the data generated by this precise characterization of diabetes-related complications will contribute to our understanding of the development and course of such complications, and thus facilitate the implementation of tailored treatment options that can reduce the risk and severity of diabetes-related complications.
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http://dx.doi.org/10.1055/a-1221-9618DOI Listing
September 2020

Increased Hepatic ACE2 Expression in NAFL and Diabetes-A Risk for COVID-19 Patients?

Diabetes Care 2020 10 4;43(10):e134-e136. Epub 2020 Aug 4.

Institute for Clinical Chemistry and Pathobiochemistry, University Hospital Tübingen, Tübingen, Germany

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http://dx.doi.org/10.2337/dc20-1458DOI Listing
October 2020

Benefit/risk profile of dapagliflozin 5 mg in the DEPICT-1 and -2 trials in individuals with type 1 diabetes and body mass index ≥27 kg/m.

Diabetes Obes Metab 2020 11 20;22(11):2151-2160. Epub 2020 Aug 20.

Schneider Children's Medical Center of Israel, Petah Tikva, Israel.

Aim: The DEPICT-1 and -2 studies (NCT02268214, NCT02460978) evaluated the efficacy and safety of dapagliflozin in individuals with type 1 diabetes who were receiving intensive insulin therapy. The DEPICT-1 and -2 studies (NCT02268214, NCT02460978) evaluated the efficacy and safety of dapagliflozin in individuals with type 1 diabetes. This post-hoc study investigated the safety and efficacy of dapagliflozin in individuals with BMI ≥27 kg/m to assess if the benefit/risk ratio associated with dapagliflozin treatment can be further improved than that observed in the overall DEPICT population.

Methods: Changes in glycated haemoglobin (HbA1c) and body weight, percentage change in daily insulin dose and proportion of participants achieving HbA1c reduction ≥0.5% without severe hypoglycaemia were evaluated at weeks 24 and 52. Changes in mean interstitial glucose, mean amplitude of glycaemic excursions and time in target glycaemic range were evaluated at week 24. Safety was assessed until week 56.

Results: Week-52 adjusted mean (SE) change from baseline for HbA1c was -0.26% (0.05) with dapagliflozin versus +0.08% (0.05) with placebo and for body weight was -2.74 kg (0.25) with dapagliflozin versus +0.81 kg (0.26) with placebo. Mean (SE) percentage change in daily insulin dose was -10.5% (1.23) with dapagliflozin versus -1.4% (1.36) with placebo. Time spent in target glycaemic range increased by 2.2 h/day versus placebo. Dapagliflozin was well tolerated, with fewer participants experiencing diabetic ketoacidosis (dapagliflozin, 1.7%; placebo, 1.0%) than dapagliflozin 5 mg receiving participants in the pooled DEPICT populations.

Conclusions: Compared with the pooled DEPICT population, the benefit/risk profile of adjunct dapagliflozin therapy was more favourable in individuals with type 1 diabetes with body mass index ≥27 kg/m because of the reduced risk of diabetic ketoacidosis in this population.
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http://dx.doi.org/10.1111/dom.14144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693058PMC
November 2020

Disruption of the sodium-dependent citrate transporter SLC13A5 in mice causes alterations in brain citrate levels and neuronal network excitability in the hippocampus.

Neurobiol Dis 2020 09 16;143:105018. Epub 2020 Jul 16.

Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany. Electronic address:

In addition to tissues such as liver, the plasma membrane sodium-dependent citrate transporter, NaCT (SLC13A5), is highly expressed in brain neurons, but its function is not understood. Loss-of-function mutations in the human SLC13A5 gene have been associated with severe neonatal encephalopathy and pharmacoresistant seizures. The molecular mechanisms of these neurological alterations are not clear. We performed a detailed examination of a Slc13a5 deletion mouse model including video-EEG monitoring, behavioral tests, and electrophysiologic, proteomic, and metabolomic analyses of brain and cerebrospinal fluid. The experiments revealed an increased propensity for epileptic seizures, proepileptogenic neuronal excitability changes in the hippocampus, and significant citrate alterations in the CSF and brain tissue of Slc13a5 deficient mice, which may underlie the neurological abnormalities. These data demonstrate that SLC13A5 is involved in brain citrate regulation and suggest that abnormalities in this regulation can induce seizures. The present study is the first to (i) establish the Slc13a5-knockout mouse model as a helpful tool to study the neuronal functions of NaCT and characterize the molecular mechanisms by which functional deficiency of this citrate transporter causes epilepsy and impairs neuronal function; (ii) evaluate all hypotheses that have previously been suggested on theoretical grounds to explain the neurological phenotype of SLC13A5 mutations; and (iii) indicate that alterations in brain citrate levels result in neuronal network excitability and increased seizure propensity.
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http://dx.doi.org/10.1016/j.nbd.2020.105018DOI Listing
September 2020