Novel loci for adiponectin levels and their influence on type 2 diabetes and metabolic traits: a multi-ethnic meta-analysis of 45,891 individuals.

Circulating levels of adiponectin, a hormone produced predominantly by adipocytes, are highly heritable and are inversely associated with type 2 diabetes mellitus (T2D) and other metabolic traits. We conducted a meta-analysis of genome-wide association studies in 39,883 individuals of European ancestry to identify genes associated with metabolic disease. We identified 8 novel loci associated with adiponectin levels and confirmed 2 previously reported loci (P = 4.5×10(-8)-1.2×10(-43)). Using a novel method to combine data across ethnicities (N = 4,232 African Americans, N = 1,776 Asians, and N = 29,347 Europeans), we identified two additional novel loci. Expression analyses of 436 human adipocyte samples revealed that mRNA levels of 18 genes at candidate regions were associated with adiponectin concentrations after accounting for multiple testing (p<3×10(-4)). We next developed a multi-SNP genotypic risk score to test the association of adiponectin decreasing risk alleles on metabolic traits and diseases using consortia-level meta-analytic data. This risk score was associated with increased risk of T2D (p = 4.3×10(-3), n = 22,044), increased triglycerides (p = 2.6×10(-14), n = 93,440), increased waist-to-hip ratio (p = 1.8×10(-5), n = 77,167), increased glucose two hours post oral glucose tolerance testing (p = 4.4×10(-3), n = 15,234), increased fasting insulin (p = 0.015, n = 48,238), but with lower in HDL-cholesterol concentrations (p = 4.5×10(-13), n = 96,748) and decreased BMI (p = 1.4×10(-4), n = 121,335). These findings identify novel genetic determinants of adiponectin levels, which, taken together, influence risk of T2D and markers of insulin resistance.

Renal responses to three types of renin-angiotensin system blockers in patients with diabetes mellitus on a high-salt diet: a need for higher doses in diabetic patients?

Objective Activation of the renal renin-angiotensin system in patients with diabetes mellitus appears to contribute to the risk of nephropathy. Recently, it has been recognized than an elevation of prorenin in plasma also provides a strong indication of risk of nephropathy. This study was designed to examine renin-angiotensin system control mechanisms in the patient with diabetes mellitus.Methods We enrolled 43 individuals with type 2 diabetes mellitus. All individuals were on a high-salt diet to minimize the contribution of the systemic renin-angiotensin system. After an acute exposure to captopril (25 mg), they were randomized to treatment with either irbesartan (300 mg) or aliskiren (300 mg) for 2 weeks.Results All agents acutely lowered blood pressure and plasma aldosterone, and increased renal plasma flow and glomerular filtration rate. Yet, only captopril and aliskiren acutely increased plasma renin and decreased plasma angiotensin II, whereas irbesartan acutely affected neither renin nor angiotensin II. Plasma renin and angiotensin II subsequently did increase upon chronic irbesartan treatment. When given on day 14, irbesartan and aliskiren again induced the above hemodynamic, renal and adrenal effects, yet without significantly changing plasma renin. Irbesartan at that time did not affect plasma angiotensin II, whereas aliskiren lowered it to almost zero.Conclusion The relative resistance of the renal renin response to acute (irbesartan) and chronic (irbesartan and aliskiren) renin-angiotensin system blockade supports the concept of an activated renal renin-angiotensin system in diabetes, particularly at the level of the juxtaglomerular cell, and implies that diabetic patients might require higher doses of renin-angiotensin system blockers to fully suppress the renal renin-angiotensin system. J Hypertens 29: 2454-2461 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Re: Cost effectiveness of strategies to combat cardiovascular disease, diabetes, and tobacco use in sub-Saharan Africa and South East Asia: mathematical modelling study.

Rapid response to: Ortegón M, Lim S, Chisholm D, Mendis S. Cost effectiveness of strategies to combat cardiovascular disease, diabetes, and tobacco use in sub-Saharan Africa and South East Asia: mathematical modelling study. BMJ. 2012 Mar 2;344:e607. doi: 10.1136/bmj.e607. PMID: 22389337.

RasGAP-derived fragment N increases the resistance of beta cells towards apoptosis in NOD mice and delays the progression from mild to overt diabetes.

The caspase-3-generated RasGAP N-terminal fragment (fragment N) inhibits apoptosis in a Ras-PI3K-Akt-dependent manner. Fragment N protects various cell types, including insulin-secreting cells, against different types of stresses. Whether fragment N exerts a protective role during the development of type 1 diabetes is however not known. Non-obese diabetic (NOD) mice represent a well-known model for spontaneous development of type 1 diabetes that shares similarities with the diseases encountered in humans. To assess the role of fragment N in type 1 diabetes development, a transgene encoding fragment N under the control of the rat insulin promoter (RIP) was back-crossed into the NOD background creating the NOD-RIPN strain. Despite a mosaic expression of fragment N in the beta cell population of NOD-RIPN mice, islets isolated from these mice were more resistant to apoptosis than control NOD islets. Islet lymphocytic infiltration and occurrence of a mild increase in glycemia developed with the same kinetics in both strains. However, the period of time separating the mild increase in glycemia and overt diabetes was significantly longer in NOD-RIPN mice compared to the control NOD mice. There was also a significant decrease in the number of apoptotic beta cells in situ at 16 weeks of age in the NOD-RIPN mice. Fragment N exerts therefore a protective effect on beta cells within the pro-diabetogenic NOD background and this prevents a fast progression from mild to overt diabetes.

CoLaus: diabète et dyslipidémie, il y a toujours du nouveau ! [CoLaus: diabetes and dyslipidemia, there is always something to new !].

Résumé : Les maladies cardiovasculaires restent la première cause de mortalité dans notre pays. Elles sont associées à des facteurs de risque (FRCV) bien connus comme le diabète ou la dyslipidémie. Nous résumons ici les principaux résultats de l'étude CoLaus concernant d'une part la prévalence du diabète et de la dyslipidémie et certaines caractéristiques de leur prise en charge.Les découvertes récentes concernant de nouveaux déterminants génétiques impliqués dans ces FRCV sont présentées de manière succincte. La contribution de ces données génétiques est également discutée dans une perspective de prise en charge clinique.[Abstract] Cardiovascular diseases remain the first cause of mortality in our country. They are associated with well known risk factors such as diabetes and dyslipidemia. Herein we summarize main results of the CoLaus study regarding, first the prevalence and characteristics of the treatment of these risk factors.Then we present recent discoveries of new genetic determinants associated with these risk factors. Finally, we discuss whether this knowledge changes our current clinical management of our patients.

Prevention of microalbuminuria in patients with type 2 diabetes: what do we know?

Cardiovascular and chronic kidney disease are epidemic throughout industrialized societies. Diabetes leads to premature cardiovascular disease and is regarded by many as the most common etiological factor for chronic kidney disease. Because most studies of blood-pressure lowering agents in people with diabetes and hypertension have been conducted in individuals who already have some target organ damage, it is unclear whether earlier intervention could prevent or delay the onset of renal or systemic vascular disease. In early disease there is only a low possibility of observing cardiovascular or renal events; thus intervention trials in this population must rely on disease markers such as microalbuminuria. Accordingly, the authors review the evidence to support the use of microalbuminuria as a disease marker in diabetic patients based on its strong association with renal and cardiovascular events, and discuss recent trials that examine the impact of preventing or delaying the onset of microalbuminuria.

Could moderate alcohol consumption help prevent the metabolic syndrome and diabetes mellitus ?

Aim and purpose: Moderate alcohol consumption has been associated with lower risk of diabetes mellitus, but few data exist on the metabolic syndrome and on the metabolic impact of heavy drinking. The aim of our study was to investigate the complex relationship between alcohol and the metabolic syndrome and diabetes mellitus in a population-based study in Switzerland with high mean alcohol consumption. Design and methods: In 6188 adults aged 35 to 75, alcohol consumption was categorized as 0, 1-6, 7-13, 14-20, 21-27, 28-34 and >= 35 drinks/week or as nondrinkers, moderate (1-13 drinks), high (14-34 drinks) and very high (>= 35 drinks) alcohol consumption. The metabolic syndrome was defined according to the ATP-III criteria and diabetes mellitus as fasting glycemia >= 7 mmol/l or self-reported medication.We used multivariate analysis adjusted for age, gender, smoking status, physical activity and education level to determine the prevalence of the conditions according to drinking categories. Results: 73% (n = 4502) of the participants consumed alcohol, 16% (n = 993) were high drinkers and 2% (n = 126) very high drinkers. In multivariate analysis, alcohol consumption had a U-shaped relationship with the metabolic syndrome and diabetes mellitus. The prevalence of the metabolic syndrome significantly differed between nondrinkers (24%), moderate (19%), high (20%) and very high drinkers (29%) (P<= 0.005). The prevalence of diabetes mellitus also significantly differed between nondrinkers (6.0%), moderate (3.6%), high (3.8%) and very high drinkers (6.7%) (P<= 0.05). These relationships did not differ according to beverage types. Conclusions: The prevalence of the metabolic syndrome and diabetes mellitus decrease with moderate alcohol consumption and increase with heavy drinking, without differences according to beverage types. Recommending to limit alcohol consumption to 1-2 drinks/day might help prevent these conditions in primary care Metabolic Syndrome and Diabetes Mellitus.

Neonatal hyperglycemia inhibits angiogenesis and induces inflammation and neuronal degeneration in the retina.

Recent evidence suggests that transient hyperglycemia in extremely low birth weight infants is strongly associated with the occurrence of retinopathy of prematurity (ROP). We propose a new model of Neonatal Hyperglycemia-induced Retinopathy (NHIR) that mimics many aspects of retinopathy of prematurity. Hyperglycemia was induced in newborn rat pups by injection of streptozocine (STZ) at post natal day one (P1). At various time points, animals were assessed for vascular abnormalities, neuronal cell death and accumulation and activation of microglial cells. We here report that streptozotocin induced a rapid and sustained increase of glycemia from P2/3 to P6 without affecting rat pups gain weight or necessitating insulin treatment. Retinal vascular area was significantly reduced in P6 hyperglycemic animals compared to control animals. Hyperglycemia was associated with (i) CCL2 chemokine induction at P6, (ii) a significant recruitment of inflammatory macrophages and an increase in total number of Iba+ macrophages/microglia cells in the inner nuclear layer (INL), and (iii) excessive apoptosis in the INL. NHIR thereby reproduces several aspects of ischemic retinopathies, including ROP and diabetic retinopathies, and might be a useful model to decipher hyperglycemia-induced cellular and molecular mechanisms in the small rodent.

Novel relationship between Vegf expression and retinal pigmented epithelium permeability following light damage in the mouse retina

Purpose:In the retina, the balance between pro- and anti-angiogenic factors is critical for angiogenesis control but is also involved in cell survival and maintenance. For instance, the anti-angiogenic factor PEDF is neuroprotective for photoreceptors (PRs) in models of retinal degeneration. We previously reported upregulation of VEGF (24h to 48h post lesion) in the light-damage (LD) model. Furthermore, systemic delivery of PEDF, as well as lentiviral gene transfer of an anti-VEGF antibody rescue PRs from cell death. Studies in vitro show that VEGF induces retinal endothelial cells apoptosis via the alteration of the Akt1/p38 MAPK signalling pathway under hypoxic conditions. Thus, in this study, we investigate the effect of high levels of VEGF on retinal pigmented epithelium (RPE) permeability and molecular targets expression after light-induced PR degeneration. Methods:To characterize the action of VEGF in the retina during the course of LD, we exposed adult Balb/c mice to 5'000 lux for 1h, and we collected neural retinas and eye-cups (containing RPE) at different time points after the LD. We analysed protein expression by Elisa and Western blotting. In order to study RPE cell permeability after the LD we stained β-catenin on flat mounted RPE. Results:In the neural retina, preliminary results indicate that high levels of VEGF induce a significant upregulation of VEGF receptor 2, whereas VEGF receptor 1 expression is decreased. Concomitantly with VEGF upregulation, LD increases the Src phosphorylation between 24h to 48h. Furthermore, we observe that β-catenin translocates to the cytoplasm of RPE cells between 24h to 36h after the lesion, indicating an increase on the RPE permeability, which could contribute indirectly to the deleterious effect of VEGF observed during light-induced PR apoptosis. Conclusions:This study further involves VEGF in LD and highlights the prime importance of angiogenic factor balance for PR survival. Our results suggest that PR apoptosis is augmented by RPE cell permeability, which may induce high level of VEGF and could be deleterious. The specific action of RPE permeability on PR survival and the role of Src in the retina are under investigation.

Trends in self-reported prevalence and management of hypertension, dyslipidaemia and diabetes in adults in Switzerland, 1992-2007

Purpose: to assess the trends of self-reported prevalence of cardiovascular risk factors (CV RFs: hypertension, dyslipidaemia, diabetes) and their management for period 1992 to 2007 in the Swiss population. Methods: four National health interview surveys conducted between 1992 and 2007 in representative samples of the Swiss population (63,782 subjects overall). Self-reported CV RFs prevalence, treatment and controllevels were computed after weighting. Weights were calculated by raking ratio such that the marginal distribution of the weighted totals conforms to the marginal distribution of the targeted population. Multivariate analysis adjusted on age, sex, education, nationality and SMI was conducted using logistic regression. Results: prevalence of ail CV RFs increased between 1992 and 2007, see table. Although the self-reported prevalence of treatment among subjects with CV RFs increased, and this was confirmed by multivariate analysis: OR for hypocholesterolaemic treatment relative to 1992: 0.64 [0.52-0.78]; 1.39 [1.18-1.65] and 2.00 [1.69-2.36] for 1997, 2002 and 2007, respectively. Still, in 2007, circa 40% of hypertensive, 60% of dyslipidaemic and 50% of diabetic subjects weren't treated. Conversely, an adequate control of CV RFs was reported by treated subjects, with an increase during the study period. This increase was confirmed by multivariate analysis (not shown). Conclusion: the self-reported prevalence of hypertension, dyslipidaemia and diabetes increased between 1992 and 2007 in the Swiss population. Despite a good control of treated subjects, still a significant percentage of subjects with CV RFs are not treated.

Current genetic data do not improve the prediction of type 2 diabetes mellitus: the CoLaus study.

CONTEXT: Several genetic risk scores to identify asymptomatic subjects at high risk of developing type 2 diabetes mellitus (T2DM) have been proposed, but it is unclear whether they add extra information to risk scores based on clinical and biological data. OBJECTIVE: The objective of the study was to assess the extra clinical value of genetic risk scores in predicting the occurrence of T2DM. DESIGN: This was a prospective study, with a mean follow-up time of 5 yr. SETTING AND SUBJECTS: The study included 2824 nondiabetic participants (1548 women, 52 ± 10 yr). MAIN OUTCOME MEASURE: Six genetic risk scores for T2DM were tested. Four were derived from the literature and two were created combining all (n = 24) or shared (n = 9) single-nucleotide polymorphisms of the previous scores. A previously validated clinic + biological risk score for T2DM was used as reference. RESULTS: Two hundred seven participants (7.3%) developed T2DM during follow-up. On bivariate analysis, no differences were found for all but one genetic score between nondiabetic and diabetic participants. After adjusting for the validated clinic + biological risk score, none of the genetic scores improved discrimination, as assessed by changes in the area under the receiver-operating characteristic curve (range -0.4 to -0.1%), sensitivity (-2.9 to -1.0%), specificity (0.0-0.1%), and positive (-6.6 to +0.7%) and negative (-0.2 to 0.0%) predictive values. Similarly, no improvement in T2DM risk prediction was found: net reclassification index ranging from -5.3 to -1.6% and nonsignificant (P ≥ 0.49) integrated discrimination improvement. CONCLUSIONS: In this study, adding genetic information to a previously validated clinic + biological score does not seem to improve the prediction of T2DM.

Altered distribution of juxtaparanodal kv1.2 subunits mediates peripheral nerve hyperexcitability in type 2 diabetes mellitus.

Peripheral nerve hyperexcitability (PNH) is one of the distal peripheral neuropathy phenotypes often present in patients affected by type 2 diabetes mellitus (T2DM). Through in vivo and ex vivo electrophysiological recordings in db/db mice, a model of T2DM, we observed that, in addition to reduced nerve conduction velocity, db/db mice also develop PNH. By using pharmacological inhibitors, we demonstrated that the PNH is mediated by the decreased activity of K(v)1-channels. In agreement with these data, we observed that the diabetic condition led to a reduced presence of the K(v)1.2-subunits in juxtaparanodal regions of peripheral nerves in db/db mice and in nerve biopsies from T2DM patients. Together, these observations indicate that the T2DM condition leads to potassium channel-mediated PNH, thus identifying them as a potential drug target to treat some of the DPN related symptoms.

CoLaus: diabète et dyslipidémie, il y a toujours du nouveau [CoLaus: diabetes and dyslipidemia, there is always something new!].

Cardiovascular diseases remain the first cause of mortality in our country. They are associated with well known risk factors such as diabetes and dyslipidemia. Herein we summarize main results of the CoLaus study regarding, first the prevalence and characteristics of the treatment of these risk factors. Then we present recent discoveries of new genetic determinants associated with these risk factors. Finally, we discuss whether this knowledge changes our current clinical management of our patients.