Effect of liraglutide on microcirculation in rat model with absolute insulin deficiency

INTRODUCTION

The investigations of angiotropic effects of liraglutide are an issue of significant scientific and practical interest. The successful application of liraglutide has been shown in glycemic control in patients with the type 2 diabetes mellitus (DM), but the effect of liraglutide in patients with type 1 DM has not been completely studied yet in clinical practice. Therefore, the present study is aimed to investigate the effect of liraglutide which is agonist of glucagon-like peptide-1 receptors, on microcirculation in white outbred rats with the alloxan-induced diabetes.

MATERIALS AND METHODS

The study was performed with 70 white outbred rats, divided into 4 groups: 1) control group (intact animals (Control)); 2) comparison group (diabetes mellitus (DM)) - animals with the alloxan-induced diabetes; 3) experimental group no. 1 (liraglutide low dose (LLD)) - animals with the alloxan-induced diabetes, which were injected by liraglutide at dosage of 0.2 mg/kg of animal weight per a day; 4) experimental group no. 2 (liraglutide high dose (LHD)) - animals with the alloxan-induced diabetes, which were injected by liraglutide at dosage of 0.4 mg/kg of animal weight per a day. The carbohydrate metabolism disorders, the microcirculation of posterior paw skin, as well as the concentration of catecholamines and markers of endothelial alteration in blood were estimated at the 42nd day of the experiment in the comparison and experimental groups.

RESULTS

It was found that the correction of carbohydrate metabolism by liraglutide is succeeded by the normalization of skin perfusion of posterior paw skin of the experimental animals. Recovery of microcirculation is associated with a decrease in vascular tone and stimulation of endothelium-dependent vasodilation, caused by simultaneous decrease of catecholamines, endothelin-1 and asymmetric dimethylarginine (ADMA) concentrations in blood serum. At the same time, the administration of liraglutide on the background of insulin-deficiency results in decrease of endothelial cell alteration markers concentration in blood, such as sE-selectin, syndecan-1, and vascular endothelial growth factor (VEGF).

CONCLUSION

Administration of liraglutide leads to the normalization of the carbohydrate metabolism simultaneously with the correction of microcirculation in rats with the absolute insulin deficiency. The demonstrated recovery of microcirculation by liraglutide, which represents an analogue of glucagon-like peptide-1, provides new prospects for its approval as a potential drug for pathogenetic correction of microcirculatory disorders in patients with the type 1 DM.

Microcirculatory dopplerography as a method to evaluate drugs endothelial protective properties in type 2 diabetic patients

Objective - to identify the most accurate way of drugs endothelial protective properties evaluation. Material and methods. Blood endothelin-1 (E) and acetylcholine-induced endothelial dependent vasodilation (EDV) were measured for 9 months in type 2 diabetic patients receiving either metformin (MET) (group 1) or MET and liraglutide (LIR) (group 2). Results. E was normal in group 1 at baseline and decreased only with glycaemia decline, in group 2 it was primarily increased and declined independently on glycaemia dynamics. In both groups E normalized in 6 months. EDV was impaired primarily in groups 1 and 2 and normalized only in group 2 in 9 months. Conclusions. LIR improves endothelial function, independently on glycaemia. Dopplerography in more accurate in drugs endothelial protective effects evaluation than circulating markers.