Autori: A. Georgescu, D. Popov, A. Constantin, M. Nemecz, N. Alexandru, D. Cochior, A.Tudor.
Editorial: Clinical Science, 120 (9/10), p.463-472, 2011.
The aim of the present study was to examine the effects of obesity alone and obesity associated with Type 2 diabetes on the structure, vascular reactivity and response to insulin of isolated human subcutaneous fat arterioles; these effects were correlated with the expression of insulin-signalling proteins. Periumbilical subcutaneous adipose tissue was explanted during surgery, small arterioles(internal diameter 220+−
40 μm) were dissected out and investigated by electron microscopy,
myography and immunoblotting.
Compared with the subcutaneous arterioles of lean subjects,obesity activated the endothelium, enhanced the accumulation of collagen within vascular wall and increased the sensitivity of adrenergic response; obesity also diminished eNOS (endothelial NO synthase) protein expression, NO production, and endothelium-dependent and insulin-induced vasodilatation, as well as the protein expression of both IRS (insulin receptor substrates)-1 and IRS-2 and of the downstream molecules in insulin pathway, such as PI3K (phosphoinositide 3-kinase), phospho-Akt and Akt. When obesity was joined with Type 2 diabetes, these changes are significantly augmented.
In conclusion, obesity alone or obesity associated with Type 2 diabetes alters human periumbilical adipose tissue arterioles in terms of structure, function and biochemsitry, including diminished eNOS expression and reduced levels of IRS-1, IRS-2, PI3K and Akt in the insulin signalling pathway.
Cuvinte cheie: arteriole, endothelial dysfunction, insulin signalling, obesity, Type 2 diabetes.