Adiponectin: a link between excess adiposity and associated comorbidities?

Abstract

Adiponectin is a novel polypeptide that is highly specific to adipose tissue. In contrast to other adipocytokines, adiponectin levels are decreased in obesity and associated comorbidities, such as type 2 diabetes. Decreased expression of adiponectin is correlated with insulin resistance. It has been suggested that several agents, such as tumor necrosis factor alpha, could mediate their effects on insulin metabolism through modulating adiponectin secretion from adipocytes. The mechanisms for the development of atherosclerotic vascular disease in obese individuals are largely unknown. Several findings support the interesting hypothesis that adiponectin could be a link between obesity and related atherosclerosis. First, adiponectin levels are lower in patients with coronary artery disease. Second, adiponectin modulates endothelial function and has an inhibitory effect on vascular smooth muscle cell proliferation. Moreover, adiponectin is accumulated more preferably to the injured vascular wall than intact vessels and has been shown to suppress macrophage-to-foam cell transformation. Adiponectin may also be involved in the modulation of inflammation. Thiazolidinediones, antiatherogenic and other effects have been explained by their direct enhancing effect on adiponectin. In conclusion, adiponectin has anti-inflammatory and antiatherogeneic effects as well as multiple beneficial effects on metabolism. Therefore it is not a surprise that adiponectin therapy has been tested in animal models of obesity, and it has been shown to ameliorate hyperglycemia and hyperinsulinemia without inducing weight gain or even inducing weight loss in some studies. Unlike agents that exert their effects centrally, adiponectin's effects seem to be peripherally mediated. The evidence of an association between adiponectin and the metabolic and cardiovascular complications of obesity is growing all the time.

Ghrelin and hormonal markers under exercise training in patients with heart failure with preserved ejection fraction: results from the Ex‐DHF pilot study

“…While body mass index did not change in either treatment group in the Ex‐DHF‐P trial,7 fat mass and detailed body composition assessments were unfortunately not available in our patients. Levels of the hormone are previously shown to be inversely correlated with body fat percentage in adults 26. Adiponectin is known to suppress TNF‐ α production and to possess direct anti‐inflammatory effects.…”

Obesity and related consequences to ageing

“…Studies on obese subjects showed that adiponectin levels are inversely correlated with body fat percentage in adults (Ukkola and Santaniemi 2002). Lower adiponectin concentrations in obese animals were associated with chronic inflammation, increased TNF-α, and altered glucose and insulin homeostasis (Hernandez-Bautista et al 2014).…”

“…Lean individuals with small adipocytes are metabolically homeostatic, but enlarged adipocytes in overweight or obese subjects promote inflammation due to macrophage recruitment. In parallel with fat mass enlargement, as the metabolic role of adipocytes changes, the secretion of various hormones, such as adiponectin, is affected (Ukkola and Santaniemi 2002;Frederich et al 1995). Since adiponectin naturally decreases with age and obesity accelerates the decline in adiponectin levels, one may speculate that obesity alters the ageing process through adiponectin regulation.…”

Increased plasma adiponectin concentrations are associated with microangiopathy in type 1 diabetic subjects

“…Adiponectin is a hormone that is secreted by adipocytes to regulate glucose and lipid metabolism [8]. The finding that adiponectin infusion reverses insulin resistance in rodent models suggests that adiponectin plays a role in this condition [9].…”