Divergent Effect of Central Incretin Receptors Inhibition in a Rat Model of Sporadic Alzheimer's Disease.

The incretin system is an emerging new field that might provide valuable contributions to the research of both the pathophysiology and therapeutic strategies in the treatment of diabetes, obesity, and neurodegenerative disorders. This study aimed to explore the roles of central glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) on cell metabolism and energy in the brain, as well as on the levels of these incretins, insulin, and glucose via inhibition of the central incretin receptors following intracerebroventricular administration of the respective antagonists in healthy rats and a streptozotocin-induced rat model of sporadic Alzheimer's disease (sAD). Chemical ablation of the central GIP receptor (GIPR) or GLP-1 receptor (GLP-1R) in healthy and diseased animals indicated a region-dependent role of incretins in brain cell energy and metabolism and central incretin-dependent modulation of peripheral hormone secretion, markedly after GIPR inhibition, as well as a dysregulation of the GLP-1 system in experimental sAD.

Renal effects of glucagon-like peptide receptor agonists in patients with type 1 diabetes mellitus.

AIM: The purpose of our study is to assess the effects of glucagon-like peptide-1 receptor agonists (GLP-1R agonists) on early markers of kidney damage in patients with type 1 diabetes mellitus (DM). MATERIALS AND METHODS: The study included 27 patients with type 1 diabetes with normo- (n=16) and microalbuminuria (n=11) on intensive insulin injection regimen with insulin analogs. Patients were divided into two groups: 15 patients continued insulin therapy throughout the follow-up period, 12 patients were given 1.2 mg GLP-1R agonist (Liraglutide) once a day in addition to the insulin therapy for 6 months. HbA1c, lipid profile, classic markers of kidney damage (albuminuria, creatinine, glomerular filtration rate); plazma (neutrophilic gelatinase-associated lipoxalin - NGAL, molecule renal damage of type 1 - KIM-1, cystatin C, osteopontin) and urinary kidney biomarkers (nephrin, podocyne, uromodulin, NGAL, KIM-1, collagen type IV, cystatin C) were evaluated prior and in dynamics at 6 months. Kidney biomarkers levels were assessed by the enzyme-linked immunosorbent assay (ELISA). RESULTS: We observed a significant decrease in the urinary excretion of type IV collagen, cystatin C, increased uromodulin excretion and decrease in the plasma levels of osteopontin, NGAL and cystatin C in the group of combined insulin and GLP-1R agonist therapy. CONCLUSION: Changes in the level of sensitive kidney biomarkers indicate a possible renoprotective effect of GLP-1R agonist therapy in patients with type 1 diabetes at an early stages of kidney damage.