Sialic acids cleavage induced by elastin-derived peptides impairs the interaction between insulin and its receptor in adipocytes 3T3-L1.

The insulin receptor (IR) plays an important role in insulin signal transduction, the defect of which is believed to be the root cause of type 2 diabetes. In 3T3-L1 adipocytes as in other cell types, the mature IR is a heterotetrameric cell surface glycoprotein composed of two α subunits and two ß subunits. Our objective in our study, is to understand how the desialylation of N-glycan chains, induced by elastin-derived peptides, plays a major role in the function of the IR. Using the 3T3-L1 adipocyte line, we show that removal of the sialic acid from N-glycan chains (N893 and N908), induced by the elastin receptor complex (ERC) and elastin derived-peptides (EDPs), leads to a decrease in the autophosphorylation activity of the insulin receptor. We demonstrate by molecular dynamics approaches that the absence of sialic acids on one of these two sites is sufficient to generate local and general modifications of the structure of the IR. Biochemical approaches highlight a decrease in the interaction between insulin and its receptor when ERC sialidase activity is induced by EDPs. Therefore, desialylation by EDPs is synonymous with a decrease of IR sensitivity in adipocytes and could thus be a potential source of insulin resistance associated with diabetic conditions.

Tobacco smoking and diabetes. A comparative survey among diabetologists and smoking cessation specialists.

AIMS: Because tobacco smoking is a major risk factor of mortality in diabetes and guidelines suggest evaluating smoking behavior among individuals with diabetes and helping smokers quit, we aimed to assess knowledge about the tobacco smoking - diabetes relationship among diabetologists and smoking cessation specialists (SCS). METHODS: An online cross sectional survey was conceived by the Working Group on Smoking and Diabetes, France. The questionnaire was tested by the members of the Working Group and deemed to be completed in less than 5 min. Only questions receiving the highest number of approval ratings were kept for the survey. The questionnaire was sent to all members of the French Language Society of Diabetes (Société Francophone du Diabète, SFD), N = 969 and the French Language Society on Tobacco (Société Francophone de Tabacologie, SFT), N = 307. The mailing lists of members were obtained with the previous agreement of the societies' board. RESULTS: 225 diabetologists and 97 SCS (response rate 23.2% and 31.5%, respectively) completed the questionnaire. Over 90% of the diabetologists reported recording smoking status of their patients. Although diabetologists were aware that smoking increases all-cause mortality of individuals with diabetes, only 29.3% were aware that smoking is a risk factor for type 2 diabetes (76.3% among SCS), for poor glycemic control: 32.9% (86.6% among SCS). Significantly less diabetologists (64%) than SCS (76.3%) were aware of smoking being a risk factor for microangiopathy. More diabetologists considered that smoking cessation is more important than optimizing glycemic control among individuals with type 2 (69.3%) than among those with type 1 diabetes (47.1%). Few diabetologists (11.1%) and SCS (14.4%) reported to be trained for smoking cessation among persons with diabetes. CONCLUSION: Specific knowledge about the negative tobacco smoking - diabetes association seems to be insufficient among French diabetologists. Diabetologists but also other health care professionals should be trained to help individuals with diabetes who smoke to quit smoking.

Smoking and Diabetes: Sex and Gender Aspects and Their Effect on Vascular Diseases.

Smoking and diabetes mellitus (DM) have been identified as 2 major cardiovascular risk factors for many years. In the field of cardiovascular diseases, considering sex differences, or gender differences, or both has become an essential element in moving toward equitable and quality health care. We reviewed the effect of sex or gender on the link between smoking and DM. The risk of type 2 DM due to smoking has been established in both sexes at the same level. As is the case in the general population, the prevalence of smoking in those with DM is higher in men than in women, although the decrease in smoking observed in recent years is more pronounced in men than in women. Regarding chronic DM complications, smoking is an independent risk factor for all-cause mortality, as well as macrovascular and microvascular complications, in both sexes. Nevertheless, in type 2 DM, the burden of smoking appears to be greater in women than in men for coronary heart disease morbidity, with women having a 50% greater risk of fatal coronary event. Women are more dependent to nicotine, cumulate psychosocial barriers to quitting smoking, and are more likely to gain weight, which might make it more difficult for them to quit smoking. Smoking cessation advice and treatments should take into account gender differences to improve the success and long-term maintenance of abstinence in people with and without DM. This might include interventions that address emotions and stress in women or designed to reach specific populations of men.

Smoking and diabetes interplay: A comprehensive review and joint statement.

Evidence shows that smoking increases the risk of pre-diabetes and diabetes in the general population. Among persons with diabetes, smoking has been found to increase the risk of all-cause mortality and aggravate chronic diabetic complications and glycemic control. The current paper, which is a joint position statement by the French-Speaking Society on Tobacco (Société Francophone de Tabacologie) and the French-Speaking Society of Diabetes (Société Francophone du Diabète), summarizes the data available on the association between smoking and diabetes and on the impact of smoking and smoking cessation among individuals with type 1, type 2, and gestational diabetes mellitus. It also provides evidence-based information about the pharmacological and behavioral strategies for smoking cessation in these patients.

Burden of cardiovascular disease in a large contemporary cohort of patients with heterozygous familial hypercholesterolemia.

Background and aims: Heterozygous familial hypercholesterolemia (HeFH) is increasingly better diagnosed and treatments can improve the cardiovascular prognosis. We evaluated the long-term cardiovascular risk of HeFH using the French REgistry of Familial hypERCHOLesterolemia (REFERCHOL). Methods: We studied HeFH patients diagnosed genetically and clinically by the Dutch Lipid Clinic Network (DLCN) criteria in all lipid clinics across the country and their 5-year risk of cardiovascular events (all fatal and non-fatal acute coronary, cerebral and peripheral arterial disease events, aortic valve replacement surgery) using the French national health data system. Results: The database comprised 3202 individuals, 2010 (62.8%) with genetically verified HeFH and 1192 (37.2%) a DLCN score ≥6. Of these individuals, 2485 (77.6%) were in primary prevention and 717 (22.4%) in secondary prevention. The incidence of cardiovascular events was 24.58 per 1000 person-years for the overall sample, 19.15 in primary prevention and 43.40 in secondary prevention. The incidence of myocardial infarction, cerebral infarction and death was 16.32 per 1000 person-years for the overall sample, 12.93 in primary prevention and 28.08 in secondary prevention. The incidence of aortic valve replacement was 1.78 per 1000 person-years. In the overall sample, at inclusion, 41% were not treated for LDL cholesterol, 48% of these in primary prevention and 20% in secondary prevention and high-dose statins were used by only 24% of individuals, 15% of these in primary prevention and 45% in secondary prevention. Conclusions: The incidence of cardiovascular events in HeFH is high and lipid-lowering treatment is far from optimal. The cardiovascular risk of HeFH is underestimated and patients are inadequately treated.

CD160 Expression in Retinal Vessels Is Associated With Retinal Neovascular Diseases.

Purpose: Anti-angiogenic agents stand first in the treatment of neovascular diseases of the retina. CD160 appeared in several experimental studies as a marker of activated endothelial cells, suggesting it could represent a promising target for novel anti-angiogenic therapies. The aim of the present study was to assess the distribution of CD160 in the human eye, and to search for a possible correlation with retinal neovascular diseases. Methods: The physiological distribution of CD160 in the normal eye was assessed with immunolabeling in 10 human donor eyes. Then, in a retrospective cohort of 75 surgical retinal specimens, the density of CD160+ microvessels was evaluated, along with immunolabeling on serial sections against ERG (pan-endothelial cell marker), CD105 (activated endothelial cell marker), and α-SMA (pericyte cell marker). The cohort was divided into two groups: 29 patients with neovascular disease (NV+) and 46 control patients (NV-). Results: CD160 was physiologically expressed by several cell types: endothelial cells of retinal blood vessels, ganglion cells, macrophages, epithelial cells of the conjunctiva, ciliary body, and retinal pigment epithelium. In the patient cohort, the percentage of CD160+ vessels in the retina was significantly and independently higher in patients suffering from neovascular diseases (P = 0.04). On the contrary, the expression of CD105 was correlated neither with retinal neovascular diseases, nor with CD160 expression. Conclusions: CD160 was expressed in some retinal vessels in both normal and pathologic eyes. CD160 expression by endothelial cells of retinal vessels was correlated with ocular neovascular diseases. CD160 could therefore represent an interesting target for novel anti-angiogenic therapies.

Production of Elastin-Derived Peptides Contributes to the Development of Nonalcoholic Steatohepatitis.

Affecting more than 30% of the Western population, nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and can lead to multiple complications, including nonalcoholic steatohepatitis (NASH), cancer, hypertension, and atherosclerosis. Insulin resistance and obesity are described as potential causes of NAFLD. However, we surmised that factors such as extracellular matrix remodeling of large blood vessels, skin, or lungs may also participate in the progression of liver diseases. We studied the effects of elastin-derived peptides (EDPs), biomarkers of aging, on NAFLD progression. We evaluated the consequences of EDP accumulation in mice and of elastin receptor complex (ERC) activation on lipid storage in hepatocytes, inflammation, and fibrosis development. The accumulation of EDPs induces hepatic lipogenesis (i.e., SREBP1c and ACC), inflammation (i.e., Kupffer cells, IL-1ß, and TGF-ß), and fibrosis (collagen and elastin expression). These effects are induced by inhibition of the LKB1-AMPK pathway by ERC activation. In addition, pharmacological inhibitors of EDPs demonstrate that this EDP-driven lipogenesis and fibrosis relies on engagement of the ERC. Our data reveal a major role of EDPs in the development of NASH, and they provide new clues for understanding the relationship between NAFLD and vascular aging.

An apolipoprotein A-V gene SNP is associated with marked hypertriglyceridemia among Asian-American patients.

Apolipoprotein A-V (apoA-V) is an important regulator of plasma levels of triglyceride (TG) in mice. In humans, APOA5 genetic variation is associated with TG in several populations. In this study, we determined the effects of the p.185Gly>Cys (c.553G>T; rs2075291) polymorphism on plasma TG levels in subjects of Chinese ancestry living in the United States and in a group of non-Chinese Asian ancestry. The frequency of the less common cysteine allele was 4-fold higher (15.1% vs. 3.7%) in Chinese high-TG subjects compared with a low-TG group (Chi-square = 20.2; P < 0.0001), corresponding with a 4.45 times higher risk of hypertriglyceridemia (95% confidence interval, 2.18-9.07; P < 0.001). These results were replicated in the non-Chinese Asians. Heterozygosity was associated, in the high-TG group, with a doubling of TG (P < 0.001), mainly VLDL TG (P = 0.014). All eleven TT homozygotes had severe hypertriglyceridemia, with mean TG of 2,292 +/- 447 mg/dl. Compared with controls, carriers of the T allele had lower postheparin lipoprotein lipase activity but not hepatic lipase activity. In Asian populations, this common polymorphism can lead to profound adverse effects on lipoprotein profiles, with homozygosity accounting for a significant number of cases of severe hypertriglyceridemia. This specific apoA-V variant has a pronounced effect on TG metabolism, the mechanism of which remains to be elucidated.