SummaryBackground-Metformin might reduce insulin requirement and improve glycaemia in patients with type 1 diabetes, but whether it has cardiovascular benefits is unknown. We aimed to investigate whether metformin treatment (added to titrated insulin therapy) reduced atherosclerosis, as measured by progression of common carotid artery intima-media thickness (cIMT), in adults with type 1 diabetes at increased risk for cardiovascular disease.
Abstract-We reported aldosterone as a novel adipocyte-derived factor that regulates vascular function. We aimed to investigate molecular mechanisms, signaling pathways, and functional significance of adipocyte-derived aldosterone and to test whether adipocyte-derived aldosterone is increased in diabetes mellitus-associated obesity, which contributes to vascular dysfunction. Studies were performed in the 3T3-L1 adipocyte cell line and mature adipocytes isolated from human and mouse (C57BL/6J) adipose tissue. Mesenteric arteries with and without perivascular fat and mature adipocytes were obtained from obese diabetic db/db and control db/ϩ mice. Aldosterone synthase (CYP11B2; mRNA and protein) was detected in 3T3-L1 and mature adipocytes, which secrete aldosterone basally and in response to angiotensin II (Ang II). In 3T3-L1 adipocytes, Ang II stimulation increased aldosterone secretion and CYP11B2 expression. Ang II effects were blunted by an Ang II type 1 receptor antagonist (candesartan) and inhibitors of calcineurin (cyclosporine A and FK506) and nuclear factor of activated T-cells (VIVIT). FAD286 (aldosterone synthase inhibitor) blunted adipocyte differentiation. In candesartan-treated db/db mice (1 mg/kg per day, 4 weeks) increased plasma aldosterone, CYP11B2 expression, and aldosterone secretion were reduced. Acetylcholine-induced relaxation in db/db mesenteric arteries containing perivascular fat was improved by eplerenone (mineralocorticoid receptor antagonist) without effect in db/ϩ mice. Adipocytes possess aldosterone synthase and produce aldosterone in an Ang II/Ang II type 1 receptor/calcineurin/nuclear factor of activated T-cells-dependent manner. Functionally adipocyte-derived aldosterone regulates adipocyte differentiation and vascular function in an autocrine and paracrine manner, respectively. These novel findings identify adipocytes as a putative link between aldosterone and vascular dysfunction in diabetes mellitus-associated obesity. (Hypertension. 2012;59:1069-1078.) • Online Data Supplement
An Expert Panel group of scientists and clinicians met to consider several aspects related to non-fasting and postprandial triglycerides (TGs) and their role as risk factors for cardiovascular disease (CVD). In this context, we review recent epidemiological studies relevant to elevated non-fasting TGs as a risk factor for CVD and provide a suggested classification of non-fasting TG concentration. Secondly, we sought to describe methodologies to evaluate postprandial TG using a fat tolerance test (FTT) in the clinic. Thirdly, we discuss the role of non-fasting lipids in the treatment of postprandial hyperlipemia. Finally, we provide a series of clinical recommendations relating to non-fasting TGs based on the consensus of the Expert Panel: 1). Elevated non-fasting TGs are a risk factor for CVD. 2). The desirable non-fasting TG concentration is <2 mmol/l (<180 mg/dl). 3). For standardized postprandial testing, a single FTT meal should be given after an 8 h fast and should consist of 75 g of fat, 25 g of carbohydrates and 10 g of protein. 4). A single TG measurement 4 h after a FTT meal provides a good evaluation of the postprandial TG response. 5). Preferably, subjects with non-fasting TG levels of 1-2 mmol/l (89-180 mg/dl) should be tested with a FTT. 6). TG concentration ≤ 2.5 mmol/l (220 mg/dl) at any time after a FTT meal should be considered as a desirable postprandial TG response. 7). A higher and undesirable postprandial TG response could be treated by aggressive lifestyle modification (including nutritional supplementation) and/or TG lowering drugs like statins, fibrates and nicotinic acid.
BackgroundProprotein convertase subtilisin kexin-like 9 (PCSK9) is a secreted glycoprotein that is transcriptionally regulated by cholesterol status. It modulates levels of circulating low density lipoprotein cholesterol (LDLC) by negatively regulating low density lipoprotein receptor (LDLR) levels. PCSK9 variants that result in 'gain of function' have been linked to autosomal dominant hypercholesterolemia, while significant protection from coronary artery disease has been documented in individuals who carry 'loss of function' PCSK9 variants. PCSK9 circulates in human plasma, and we previously reported that plasma PCSK9 is positively correlated with total cholesterol and LDLC in men.ResultsHerein, we report the effects of two lipid-modulating therapies, namely statins and fibrates, on PCSK9 plasma levels in human subjects. We also document their effects on endogenous PCSK9 and LDLR expression in a human hepatocyte cell line, HepG2, using immunoprecipitation and immunoblot analyses. Changes in plasma PCSK9 following fenofibrate or gemfibrozil treatments (fibric acid derivatives) were inversely correlated with changes in LDLC levels (r = -0.558, p = 0.013). Atorvastatin administration (HMGCoA reductase inhibitor) significantly increased plasma PCSK9 (7.40%, p = 0.033) and these changes were inversely correlated with changes in LDLC levels (r = -0.393, p = 0.012). Immunoblot analyses of endogenous PCSK9 and LDLR expression by HepG2 cells in response to statins and fibrates showed that LDLR is more upregulated than PCSK9 by simvastatin (2.6× vs 1.5×, respectively at 10 μM), while fenofibrate did not induce changes in either.ConclusionThese results suggest that in vivo (1) statins directly increase PCSK9 expression while (2) fibrates affect PCSK9 expression indirectly through its modulation of cholesterol levels and (3) that these therapies could be improved by combination with a PCSK9 inhibitor, constituting a novel hypercholesterolemic therapy, since PCSK9 was significantly upregulated by both treatments.
Severe gestational hypertriglyceridemia is a potentially life threatening and complex condition to manage, requiring attention to a delicate balance between maternal and fetal needs. During pregnancy, significant alterations to lipid homeostasis occur to ensure transfer of nutrients to the fetus. In women with an underlying genetic predisposition or a secondary exacerbating factor, severe gestational hypertriglyceridemia can arise, leading to devastating complications, including acute pancreatitis. Multidisciplinary care, implementation of a low-fat diet with nutritional support, and institution of a hierarchical therapeutic approach are all crucial to reduce maternal and fetal morbidity. To avoid maternal pancreatitis, close surveillance of triglycerides throughout pregnancy with elective hospitalization for refractory cases is recommended. Careful dietary planning is required to prevent neural and retinal complications from fetal essential fatty acid deficiency. Questions remain about the safety of fibrates and plasmapheresis in pregnancy as well as the optimal timing for induction and delivery of these women. KeywordsHigh-risk pregnancy, hypertriglyceridemia, maternal-fetal medicine, pancreatitis, maternal morbidity, complicationsSevere gestational hypertriglyceridemia is a potentially life-threatening and complex condition to manage, requiring attention to a delicate balance between maternal and fetal needs. To date, there has been a lack of practical guidance for clinicians, particularly with respect to the nuances of planning a dietary prescription to avoid essential fatty acid deficiency. We highlight a prototypical case of severe gestational hypertriglyceridemia, discuss clinical considerations, and propose a real-world approach based on what is known from the literature. CaseA 27-year-old primigravada woman at 22 weeks' gestation presented to the emergency room with severe abdominal pain and nausea. Her history was significant for poorly controlled type 2 diabetes (HbA1c 7.9%) as well as hypertriglyceridemia-induced acute pancreatitis three years previously. There was no family history of lipid disorders. She had been lost to follow-up and had not been on dietary fat restriction or lipid-lowering therapy prior to her pregnancy. Her home medications were insulin determir 30 units at breakfast and bedtime, aspart 5 units with correction pre-meals, as well as a prenatal multivitamin. Upon presentation, in addition to an elevated blood glucose (12.8 mmol/L) and lipase (514 U/L), her bloodwork revealed a lipemic sample due to a markedly elevated plasma triglycerides of 99 mmol/L. Total cholesterol was also elevated at 22.3 mmol/L. Liver enzymes were normal. An abdominal ultrasound revealed a prominent pancreas with peripancreatic fluid consistent with acute pancreatitis. Fetal growth by obstetrical ultrasound was appropriate for gestational age and the amniotic fluid index was normal.She was admitted for management of severe gestational hypertriglyceridemia-induced pancreatitis. She was followed by a...
BACKGROUND: PCSK9 (proprotein convertase subtilisin/kexin type 9) is a polymorphic gene whose protein product regulates plasma LDL cholesterol (LDLC) concentrations by shuttling liver LDL receptors (LDLRs) for degradation. PCSK9 variants that cause a gain or loss of PCSK9 function are associated with hyper-or hypocholesterolemia, which increases or reduces the risk of cardiovascular disease, respectively. We studied the clinical and molecular characteristics of a novel PCSK9 loss-of-function sequence variant in a white French-Canadian family.
Background: The growing prevalence of diabetes and heightened awareness of the benefits of early and intensive disease management have increased service demands and expectations not only of primary care physicians but also of diabetes specialists. While research has addressed issues related to referral into specialist care, much less has been published about the transition from diabetes specialists back to primary care. Understanding the concerns of family physicians related to discharge of diabetes care from specialist centers can support the development of strategies that facilitate this transition and result in broader access to limited specialist services. This study was undertaken to explore primary care physician (PCP) perspectives and concerns related to reassuming responsibility for diabetes care after referral to a specialized diabetes center.
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