Morten Schütt

Simvastatin Acutely Reduces Myocardial Reperfusion Injury In Vivo by Activating the Phosphatidylinositide 3-kinase/akt Pathway

Long-term pretreatment with statins reduces myocardial injury after acute ischemia and reperfusion by increasing the expression of endothelial nitric oxide synthase (eNOS). We hypothesized that statins may act rapidly enough to protect the myocardium from ischemia/reperfusion injury when given right at the beginning of the reperfusion period and tried to delineate the role of PI 3-kinase/Akt pathway in early eNOS activation. Activated simvastatin was given intravenously 3 minutes before starting the reperfusion after temporary coronary artery occlusion (CAO) in anaesthetized rats. Simvastatin significantly increased myocardial PI 3-kinase activity, AktSer473, and eNOSSer1177 phosphorylation and reduced infarct size by 42%. Infarct size reduction as well as activation of PI 3-kinase/Akt/eNOS pathway were not observed in rats co-treated with the PI 3-kinase inhibitor wortmannin. Contribution of eNOS was further delineated using the NOS inhibitor l-NAME, which could completely block cardioprotection by the statin. In summary, simvastatin acutely reduces the extent of myocardial necrosis in normocholesterolemic rats in an NO- dependent manner by activating the PI 3-kinase/Akt pathway. This is the first study demonstrating short-term cardioprotective effects of simvastatin in an in vivo model of ischemia/reperfusion.

The HIV-1 protease inhibitor indinavir impairs insulin signalling in HepG2 hepatoma cells

Aims/hypothesis. Patients treated with human immunodeficiency virus-1 protease inhibitors often develop impaired glucose tolerance or diabetes, most likely due to an induction of insulin resistance. We therefore investigated whether the protease inhibitor indinavir alters insulin signalling. Methods. We incubated HepG2 cells for 48 h without or with indinavir (100 μmol/l). Subsequently 125I-insulin binding to the cells and the effects of insulin stimulation on insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-Thr308-phosphorylation were measured. Results. In cells not exposed to indinavir, insulin (100 nmol/l) led to rapid increases of insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-phosphorylation during the first 75 s, followed by subsequent decreases. In indinavir-treated cells, these insulin-stimulated increases during the first 75 s were reduced by 30–60 % and this was not associated with alterations in cell number or viability, insulin binding to the cells or cellular insulin-receptor substrate-1-content. Conclusion/interpretation. Effects of indinavir on initial insulin signalling could cause, or contribute to, the metabolic effects of human immunodeficiency virus-1 protease inhibitors. [Diabetologia (2000) 43: 1145–1148]

HbA1c Variability as an Independent Risk Factor for Diabetic Retinopathy in Type 1 Diabetes: A German/Austrian Multicenter Analysis on 35,891 Patients

Objective This study aimed to analyze the effect of HbA1c variability on the occurrence of diabetic retinopathy in type 1 diabetes patients. Patients and Methods 35,891 patients with childhood, adolescent or adult onset of type 1 diabetes from a large multicentre survey, the German/Austrian prospective documentation system (DPV), were analysed. Cox proportional hazard models were used to examine whether intra-individual HbA1c variability expressed as variation coefficient is an independent risk factor for the occurrence of diabetic retinopathy. Results Kaplan-Meier curves stratified by median HbA1c and variation coefficient revealed that retinopathy-free survival probability is lower when both median HbA1c and HbA1c variability are above the 50th percentile. Cox regression models confirmed this finding: After adjustment for age at diabetes onset, gender and median HbA1c, HbA1c variability was independently associated with the occurrence of diabetic retinopathy. Time-covariate interactions used to model non-proportionality indicated an effect decreasing with duration of diabetes for both median HbA1c and HbA1c variability. Predictive accuracy increased significantly when adding HbA1c variability to the Cox regression model. Conclusions In patients with type 1 diabetes, HbA1c variability adds to the risk of diabetic retinopathy independently of average metabolic control.

Daily insulin doses and injection frequencies of neutral protamine hagedorn (NPH) insulin, insulin detemir and insulin glargine in type 1 and type 2 diabetes: a multicenter analysis of 51 964 patients from the German/Austrian DPV-wiss database.

We performed a comparative analysis of the use of long‐acting insulin (analogues) neutral protamine hagedorn (NPH), detemir (Det) and glargine (Gla), and quantified injection frequencies and daily insulin doses in patients with type 1 and 2 diabetes in daily practice.

Risk of severe hypoglycemia in sulfonylurea-treated patients from diabetes centers in Germany/Austria: How big is the problem? Which patients are at risk?

We investigated the rate of severe hypoglycemic events and confounding factors in patients with type 2 diabetes treated with sulfonylurea at specialized diabetes centers, documented in the German/Austrian DPV–Wiss database.

Insulin inhibits caspase-3 activity in human renal tubular epithelial cells via the PI3-kinase/Akt pathway.

Apoptotic mechanisms in proximal renal tubular epithelial cells (PTEC) are crucial in the pathogenesis of acute kidney injury. We investigated whether insulin alters anti-apoptotic signalling in human PTEC. Cells were deprived of insulin for 0, 24 or 48 h and then stimulated with insulin for 0 or 5 min. Apoptosis was induced by camptothecin incubation. Insulin receptor kinase (IR-kinase) activity, phosphorylation of insulin receptor substrate-1 (IRS-1), IRS-1-associated PI3-kinase (p85), Ser273-phosphorylation of Akt and caspase-3 activity (C3-activity) were determined. Insulin stimulation increased the activity of IR-kinase, IRS-1 phosphorylation, p85 association with IRS-1 and Ser273-phosphorylation of Akt by at least 250%, respectively and decreased the C3-activity by 45% (p < 0.01, respectively). Deprivation of insulin for 24 and 48 h reduced basal and insulin-stimulated IR-kinase activity, IRS-1 phosphorylation, p85 association with IRS-1 and Ser273-phosphorylation of Akt by 30-40% and increased C3-activity by 15-20% (p < 0.01, respectively). Incubation with camptothecin increased C3-activity by 250-300% (p < 0.001). Subsequent insulin stimulation reversed the camptothecin induced increase of C3-activity. Our data indicate that apoptosis in PTEC is regulated by the insulin dependent PI3-kinase/Akt pathway. The enhancement of tubular-specific cell survival signals might represent a potential therapeutic tool for the protection of renal function in acute kidney injury.

Type 1 diabetes in older adults: Comparing treatments and chronic complications in the United States T1D Exchange and the German/Austrian DPV registries

AIMS Compare characteristics, therapies and clinical outcomes in older adults with type 1 diabetes in the United States T1D Exchange (T1DX) and German/Austrian Diabetes Patienten Verlaufsdokumentation (DPV) registries. METHODS Cross-sectional study of adults ≥60years old with type 1 diabetes seen in 2011-2012 in the T1DX (n=1283) and DPV (n=2014) registries. Wilcoxon rank-sum test was used for continuous variables and chi-square test for categorical variables. Adjusted analyses used generalized linear models. RESULTS Individuals in both registries were similar in body mass index (mean 27kg/m2), percent with obesity (25%) and gender (48% male). In T1DX there was longer diabetes duration (32.3 vs. 28.8years), greater use of antihypertensive medications (including ACE-I and ARBs; 85% vs. 62%), statins (68% vs. 40%), aspirin (77% vs. 21%), insulin pumps (58% vs. 18%), and less smoking (7% vs. 10%); lower adjusted mean LDL-cholesterol (84 vs. 109mg/dL), and lower adjusted mean systolic and diastolic blood pressures (128 vs. 136 and 68 vs. 74mmHg); fewer myocardial infarctions (6% vs. 9% [99% CI of difference, 1% to 5%]), strokes (2% vs. 8% [3% to 7%]), microvascular complications including microalbuminuria (17% vs. 44% [22% to 32%]) but increased depression (16.1% vs. 8.7%). Adjusted mean HbA1c levels were similar (7.5%, 58mmol/mol). CONCLUSIONS Differences between the registries included greater use of antihypertensives, statins and insulin pumps, and fewer chronic complications in the T1DX. Further research is needed to better understand the role of intensive therapy in improving outcomes in older adults with type 1 diabetes.

Recurrent hypoglycaemic episodes in a patient with Type 2 diabetes under fibrate therapy

The causal relationship between dyslipidaemia and insulin resistance, two central components of the metabolic syndrome, is still poorly understood. We describe a 76-year-old patient with Type 2 diabetes mellitus and pronounced hypertriglyceridaemia. The patient required a total insulin dose of 148 IU/day for decent glycaemic control. The addition of the fibrate gemfibrozil to her medication resulted in a remarkable reduction in triglyceride levels (from 31.7 to 7.1 mmol/l). Consequently, the patient experienced recurrent hypoglycaemic episodes concurrent with a massive reduction in insulin requirements. Eventually, the insulin dosage was reduced by more than 65% to 48 IU/day, and HbA1c levels dropped from 9% to 6.5% over a period of 5 months without alterations in lifestyle, diet, body weight, or any other blood chemical values. Thus, this case report illustrates that treatment of hypertriglyceridaemia can reduce insulin requirements and harbours the risk of hypoglycaemia in patients with insulin-treated Type 2 diabetes mellitus.

Endokrine Notfälle in der Schwangerschaft

Endocrine emergencies during pregnancy can become life-threatening for both mother and fetus. In addition to some pregnancy-linked endocrine disorders, several pre-existing forms of endocrinopathy, such as Graves disease, type 1 diabetes and adrenal insufficiency might deteriorate acutely during pregnancy. Early diagnosis and management are challenging because the classical symptoms are often modified by pregnancy. Laboratory tests are subject to altered physiological ranges and pharmacological options are limited while therapeutic goals are stricter than in the non-pregnant patient. This article focuses on endocrine emergencies complicating pregnancy.

Endokrine Notfälle in der Schwangerschaft@@@Endocrine emergencies during pregnancy

Endocrine emergencies during pregnancy can become life-threatening for both mother and fetus. In addition to some pregnancy-linked endocrine disorders, several pre-existing forms of endocrinopathy, such as Graves disease, type 1 diabetes and adrenal insufficiency might deteriorate acutely during pregnancy. Early diagnosis and management are challenging because the classical symptoms are often modified by pregnancy. Laboratory tests are subject to altered physiological ranges and pharmacological options are limited while therapeutic goals are stricter than in the non-pregnant patient. This article focuses on endocrine emergencies complicating pregnancy.