Relationship between adiponectin, obesity and insulin resistance

Abstract

Conflict of interest: noneObjectives: the conditions of obesity and overweight pose a major risk for a number of comorbidities, including clinical syndromes resulting from atherosclerotic disease. Recent studies strongly indicate that adipose tissue is an active endocrine organ that secretes bioactive factors such as adipokines. Adiponectin appears to have a regulatory role in the mechanism of insulin resistance and in the development of atherosclerosis. This systematic review aims to evaluate the anti-atherogenic effects of adiponectin and its properties to improve and mimic metabolic and vascular actions of insulin and its influence on endothelial function. Methods: a qualitative, exploratory and literature review was performed in the PubMed, Portal Capes and Scielo databases using as key-words "adiponectin", "obesity", "insulin resistance", "anti-inflammatory", "therapeutic strategies" and "future prospects". Results: evidence suggests that adiponectin has anti-atherogenic properties with anti-inflammatory effects on the vascular wall. Moreover, it modifies the vascular intracellular signaling and has indirect antioxidant effects on the human myocardium. On the other hand, there are studies suggesting that increased levels of adiponectin are paradoxically associated with a worse prognosis in heart failure syndrome, although the mechanisms are not clear. Conclusion: it is not clear whether adiponectin levels have any clinical significance for risk stratification in cardiovascular disease or if they simply reflect the activation of complex underlying mechanisms. Changes in lifestyle and some drug treatments for hypertension and coronary heart disease have shown significant effect to increase adiponectin levels, and simultaneously decrease in insulin resistance and endothelial dysfunction.

Trunk-to-Peripheral Fat Ratio Predicts Subsequent Blood Pressure Levels in Pubertal Children With Relatively Low Body Fat – Three-Year Follow-up Study –

“…31 Adiponectin is currently considered a beneficial hormone that has antiatherogenic properties at the cellular level. 32 Cellular and molecular mechanisms connecting hypertension and hypoadiponectinemia have also been suggested. 33 …”

Mice lacking have reduced signs of metabolic syndrome and non-alcoholic fatty liver disease

“…The lack of weight gain of Arv1 -/ -animals fed a HFD is highly interesting in light of increased food consumption, elevated levels of ghrelin, and lower levels of leptin. The opposite correlation has been seen in obese individuals, where leptin levels are increased and ghrelin levels decreased (32,33). These individuals are considered leptin resistant (47).…”

“…7D We next measured adiponectin levels. Adiponectin is an adipocyte-specific adipokine, whose levels correlates with insulin resistance, and is reduced in obese individuals (32,33 -/ -animals responded with normal sensitivity to the low insulin dose (0.5 U/kg) with a small decrease in blood glucose levels ( Fig. 11E; WT, closed circles; KO, open circles).…”

Very Low-Calorie Diets in Type 2 Diabetes Mellitus: Effects on Inflammation, Clinical and Metabolic Parameters

“…Adiponectin is a 244-amino acid hormone synthesized by mature white adipose tissue in subcutaneous, visceral and perivascular adiposity [42]. Adiponectin increases as fat mass decreases, and some of its functions are adipogenesis, adipocyte lipid storage (a "healthy" expansion of adipose tissue) and adipocyte insulin sensitivity via increased GLUT4-mediated glucose uptake [43]. The beneficial metabolic effects of adiponectin are in part related to its capacity to modulate the energy sensor 5′ adenosine monophosphate-activated protein kinase (AMPK) [44].…”

“…The beneficial metabolic effects of adiponectin are in part related to its capacity to modulate the energy sensor 5′ adenosine monophosphate-activated protein kinase (AMPK) [44]. The regulation of adiponectin is a very complex system; however, low plasma adiponectin levels are associated with overweight, obesity and type 2 DM [43,45]. The exact mechanisms involved in downregulation of adiponectin are not fully understood.…”