Effects of Pegylated Glucagon-Like Peptide-1 Analogue in C57Bl/6 Mice under Optimal Conditions and During Streptozotocin-Induced Diabetes

Gender Differences in the Pharmacological Actions of Pegylated Glucagon-Like Peptide-1 on Endothelial Progenitor Cells and Angiogenic Precursor Cells in a Combination of Metabolic Disorders and Lung Emphysema

In clinical practice, the metabolic syndrome (MetS) is often associated with chronic obstructive pulmonary disease (COPD). Although gender differences in MetS are well documented, little is known about sex-specific differences in the pathogenesis of COPD, especially when combined with MetS. Consequently, it is not clear whether the same treatment regime has comparable efficacy in men and women diagnosed with MetS and COPD. In the present study, using sodium glutamate, lipopolysaccharide, and cigarette smoke extract, we simulated lipid metabolism disorders, obesity, hyperglycemia, and pulmonary emphysema (comorbidity) in male and female C57BL/6 mice. We assessed the gender-specific impact of lipid metabolism disorders and pulmonary emphysema on angiogenic precursor cells (endothelial progenitor cells (EPC), pericytes, vascular smooth muscle cells, cells of the lumen of the nascent vessel), as well as the biological effects of pegylated glucagon-like peptide 1 (pegGLP-1) in this experimental paradigm. Simulation of MetS/COPD comorbidity caused an accumulation of EPC (CD45⁻CD31⁺CD34⁺), pericytes, and vascular smooth muscle cells in the lungs of female mice. In contrast, the number of cells involved in the angiogenesis decreased in the lungs of male animals. PegGLP-1 had a positive effect on lipids and area under the curve (AUC), obesity, and prevented the development of pulmonary emphysema. The severity of these effects was stronger in males than in females. Furthermore, PegGLP-1 stimulated regeneration of pulmonary endothelium. At the same time, PegGLP-1 administration caused a mobilization of EPC (CD45⁻CD31⁺CD34⁺) into the bloodstream in females and migration of precursors of angiogenesis and vascular smooth muscle cells to the lungs in male animals. Gender differences in stimulatory action of pegGLP-1 on CD31⁺ endothelial lung cells in vitro were not observed. Based on these findings, we postulated that the cellular mechanism of in vivo regeneration of lung epithelium was at least partly gender-specific. Thus, we concluded that a pegGLP-1-based treatment regime for metabolic disorder and COPD should be further developed primarily for male patients.

Role of β Cell Precursors in the Regeneration of Insulin-Producing Pancreatic β Cells under the Influence of Glucagon-Like Peptide 1

The effects of the pegylated form of glucagon-like peptide 1 (pegGLP-1) on oligopotent β cell precursors (CD45^-TER119^-CD133⁺CD49f^low) in the pancreas were studied in C57Bl/6 mice. Under conditions of streptozotocin-induced type 1 diabetes mellitus, intraperitoneal injection of pegGLP1 increased the content of β cell precursors and dithizone-stained cells in the pancreas. β Cell precursors of mice with diabetes demonstrated high self-maintenance potential. In contrast to pegGLP-1, native GLP-1 did not affect β cell precursors in diabetic animals. Treatment of a culture of β cell precursors from mice with diabetes induced the yield of dithizone-stained mononuclears. In conditioned mediums of dithizone-positive cells obtained as a result of differentiation of β cell precursors from mice with diabetes, insulin was detected after administration of pegGLP-1 (10^-7 M) and glucose (3 mmol/liter); the level of insulin increased with increasing glucose concentration (to 20 mmol/liter). The in vitro effect of pegGLP-1 did not differ from the effect of GLP-1 (10^-7 M).