Adipokines Adiponectin

There is considerable interest in the relationship between the adipocyte-derived protein adiponectin in both type 2 diabetes and CHD. Adiponectin is a 244-amino-acid protein that, despite being solely derived from adipose tissue, is paradoxically reduced in obesity (Greenberg and Obin, 2006). Circulating adiponectin levels, ranging from 0.5 to 30 ^g/ml in humans, are reportedly around 1000-fold higher than circulating levels of other hormones such as insulin and leptin. Prospective epidemiological studies have consistently demonstrated that decreased adiponectin concentrations are associated with greater insulin resistance and increased risk of type 2 diabetes, apparently independent of obesity and other potential confounders (Lindsay etal., 2002). Thus, the development of interventions that raise adiponectin levels has been proposed as a target to improve insulin sensitivity and glucose tolerance, and possibly to prevent CHD. Apart from a potentially protective role in diabetes, adiponectin could protect against cardiovascular disease by other proposed mechanisms. Adiponectin is strongly antiinflammatory acting through the NFkB pathway, down-regulates adhesion molecule expression on endothelial cells and enhances lipid clearance in numerous animal models. In line with such observations, exogenous adiponectin administration protects against the development of atherosclerosis in ApoE-deficient mice (Greenberg and Obin, 2006). Such observations suggest that decreased synthesis and release of adiponectin in subjects destined to develop, or with, diabetes could be related to accelerated atherogenesis. In humans, however, the evidence so far has been somewhat conflicting. In the Health Professionals Study, a doubling of baseline adiponectin level was reported to be associated with a statistically significant 20% reduction in myocardial infarction (MI) risk in multivariate analyses, after adjustment for age, smoking, hypertension history, lipids, glycaemic control and CRP (Pischon etal., 2004). The results from this study, based on 266 incident MI cases, have suggested that adiponectin is a major mechanistic link ('common soil') between diabetes and increased CHD risk. However, subsequent investigations in similarly sized studies have not reported significant associations between adiponectin levels and CHD risk. To help clarify the evidence, we recently reported new data from the prospective British Regional Heart Study, which involves almost 600 incident CHD deaths and events, more than twice as many as in the previous largest study (Sattar etal., 2006). Our data suggested that adiponectin levels were not predictive of incident CHD events. Whilst these data suggest that adiponectin may not protect against vascular disease, it is premature to reach this conclusion for several reasons. For example, differing molecular forms of adiponectin may reflect differing biological effects (with the high molecular form being potentially associated with slightly greater insulin sensitivity). At present, there are no prospective studies relating high-molecular-weight adiponectin with vascular events but these are urgently required. In addition, several factors associated with greater CVD risk can increase adiponectin concentrations so that its relationship with incident CVD is potentially confounded. Such factors include impaired renal function, tissue wasting and brain natriuretic peptide, the latter released from ischaemic or damaged myocardium. Clearly, further data are needed to determine whether low adiponectin in diabetes is causal related to the accelerated atherogenesis in this condition.

Supplements For Diabetics

Supplements For Diabetics

All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.

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