The impact of glucose-loading on endothelial function and inflammatory process in patients diabetes mellitus type 2: Effects of diet and hypoglycemic agents

Abstract

The role of glucose alterations in the pathogenesis of endothelial dysfunction and inflammatory process in diabetic patients remains unclear. We examined the effect of diet or metformin on endothelial function and inflammatory process during glucose loading, in patients with newly diagnosed diabetes mellitus. The study consisted of 20 patients with newly diagnosed diabetes mellitus type 2, mean age 60.2±2.7, who underwent glucose loading (75gr glucose) at baseline and 3 months after dietary instructions (n=12, group A) or after daily metformine administration for (n=8, group B). Blood samples were taken and gauge-strain plethysmography was performed at baseline and 3 hours after loading, while the protocol was performed after 3 months treatment period. Endothelium dependent dilation (EDD) and endothelium-independent dilation (EID) were expressed as the % change of flow from baseline to the maximum flow during reactive hyperemia or after sublingual nitroglycerin administration respectively. In group B, EDD was significantly decreased at 1h (from 67±27% to 54±5%, p<0.05) and recovered at 3h after loading (66±6%, p=ns). Similarly, sICAM was slightly increased at 3h (from 258±22 to 372±18 ng/ml, p=ns). After dietary treatment, EDD was also decreased at 2h after loading (from 78±10% to 52±5%, p<0.05) and recovered at 3h (70±9%, p=ns), while the increase of sICAM-1 at 3h was prevented (from 350±13 to 245±11 ng/ml p<0.05). In group A, EDD was significantly decreased at 2h after loading (from 75±9% to 48±8%, p<0.05) and recovered at 3h (73±11%, p=ns). Metformin treatment significantly improved basal EDD (83±9%, p<0.05) but it had no effect on EDD at 2h (50±9%, p<0.05) and 3h after loading (72±4%, p=ns). Furthermore, metformin decreased both basal sICAM-1 levels (from 422±36 to 382±35 ng/ml, p<0.05) and 3h after loading (from 421±34 to 377±35 ng/ml, p<0.05). Acute hyperglycemia leads to endothelial dysfunction and increased inflammatory response, in subjects with newly diagnosed diabetes mellitus. Both diet and metformin improve endothelial function and decrease sICAM-1 levels in patients with newly-diagnosed diabetes mellitus.