In patients with Type 2 diabetes, well controlled with metformin monotherapy, addition of liraglutide improves several cardiovascular risk markers beyond glycaemic control.

This study compared the effect of Glimepiride versus Vildagliptin on β-cell function and the release of intact proinsulin (PI) in patients with type 2 diabetes mellitus. Patients on metformin monotherapy were randomized to add on treatment with Vildagliptin or Glimepiride. A standardized test meal was given at baseline, after 12 and 24 weeks of treatment. Insulin, PI and blood glucose values were measured in the fasting state and postprandial for 300 min. Fasting PI levels significantly decreased in the Vildagliptin group. The area under the curve for the postprandial release of PI decreased during Vildagliptin and increased during Glimepiride treatment. The proinsulin to insulin ratio declined in the Vildagliptin group, whereas it did not change significantly in the Glimepiride group. Addition of Vildagliptin to ongoing Metformin treatment reconstitutes the disproportionality of the proinsulin to insulin secretion from the β cell.

Numerous rheological and microvascular alterations characterize the vascular pathology in patients with type 2 diabetes mellitus (T2DM). This study investigated effects of vildagliptin in comparison to glimepiride on retinal microvascular blood flow and erythrocyte deformability in T2DM.Fourty-four patients with T2DM on metformin monotherapy were included in this randomized, exploratory study over 24 weeks. Patients were randomized to receive either vildagliptin (50 mg twice daily) or glimepiride individually titrated up to 4 mg in addition to ongoing metformin treatment. Retinal microvascular blood flow (RBF) and the arteriolar wall to lumen ratio (WLR) were assessed using a laser doppler scanner. In addition, the erythrocyte elongation index (EI) was measured at different shear stresses using laserdiffractoscopy.Both treatments improved glycaemic control (p < 0.05 vs. baseline; respectively). While only slight changes in RBF and the WLR could be observed during treatment with glimepiride, vildagliptin significantly increased retinal blood flow and decreased the arterial WLR (p < 0.05 vs. baseline respectively). The EI increased during both treatments over a wide range of applied shear stresses (p < 0.05 vs. baseline). An inverse correlation could be observed between improved glycaemic control (HbA1c) and EI (r = −0.524; p < 0.0001) but not with the changes in retinal microvascular measurements.Our results suggest that vildagliptin might exert beneficial effects on retinal microvascular blood flow beyond glucose control. In contrast, the improvement in erythrocyte deformability observed in both treatment groups, seems to be a correlate of improved glycaemic control.

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In patients with diabetes mellitus (DM), early retinal microvascular alterations can be observed even before the clinical diagnosis of diabetic retinopathy. This study aimed to investigate morphological and functional changes in retinal microvascular blood flow in type 1 diabetic patients with and without peripheral neuropathy (PNP) as compared to nondiabetic controls. Retinal microvascular blood flow (RBF) was assessed using scanning laser Doppler flowmetry (Heidelberg Retina Flowmeter, Heidelberg Engineering, Germany) before and after stimulation with flicker light. PNP was assessed using the neuropathy disability score (NDS) and by the evaluation of the vibration perception threshold (VPT). A total of 41 subjects were recruited for study participation and were stratified to 3 different groups according to their metabolic and neurological status: 14 nondiabetic subjects without PNP, 14 diabetic patients without PNP, and 13 diabetic patients with PNP. All subjects were free from diabetic retinopathy as assessed by fundoscopy. In diabetic patients with PNP, baseline and stimulated RBF was higher compared with diabetic patients without PNP and the nondiabetic control group. No difference with regard to RBF could be observed between the nondiabetic control subjects and patients with type 1 DM without PNP. No difference in the arterial WLR could be observed between the 3 groups. A linear correlation was found for VPT and RBF (r = .38, P < .001) and for NDS and RBF (r = .44, P < .0001). In our study population of patients with type 1 diabetes, PNP was associated with functional but not morphological changes in RBF. Keywords diabetic polyneuropathy, retinal blood flow, wall to lumen ratio, type 1 diabetes mellitus