Glycated collagen as an underlying mechanism for endothelial dysfunction in Diabetes

• Grant number: 24/02620-0
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: May 01, 2024
• End date: April 30, 2028
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Renato Simões Gaspar
• Grantee: Samuel Duarte Maia
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 22/05750-7 - Underlying mechanisms of cardiovascular outcomes in Diabetes: the role of glycated collagen, AP.GR

Abstract

Diabetes is a disease defined by the faulty glucose metabolism leading to hyperglycemia and is an important and growing cause of early mortality worldwide. This scenario is concerning since diabetics are at an increased risk of developing cardiovascular diseases mainly due to endothelial dysfunction and thrombus formation caused by chronic hyperglycemia. Moreover, the use of anti-hyperglycemic drugs only partially reduces this risk. Thus, the hypothesis arises that chronic hyperglycemia occurring before diagnosis causes glycation of long-lived macromolecules in the vascular matrix, and that such alteration leads to endothelial dysfunction and thrombus formation. In light of this, we aim to evaluate whether glycation of type I collagen is a mechanism underlying endothelial dysfunction and thrombus formation in diabetes. For such, in vitro experiments will expose collagen to different concentrations of methylglyoxal for 7 days at 37 °C. Endothelial cell culture (HUVECs) will be left to adhere to glycated or non-glycated collagen surfaces. We will conduct platelet adhesion experiments to HUVECs, as well as explore potential mechanisms related to the extracellular matrix. These findings will be translated into in vivo experiments, where approximately 8-week-old C57Bl mice will be induced to develop diabetes by injection with streptozotocin (i.p. 40mg/kg dissolved in 0.1M pH4.5 citrate buffer) or vehicle (citrate buffer). After diabetes development, the animals will be treated with the RAGE inhibitor Azeliragon, or an equiosmotic control (0.01% DMSO) via oral gavage for 14 days. Animals will then be euthanized, and blood and artery will be collected and subjected to platelet function evaluation, vascular reactivity, immunofluorescence, and western blotting. The hypothesis of this study considers that endothelial cells adhered to glycated collagen induce greater platelet adhesion, favoring vascular dysfunction. Such a mechanism may increase the cardiovascular risk of diabetic patients. We hypothesize that glycated collagen will induce complement activation of RAGE in endothelial cells, thereby increasing vascular dysfunction in diabetic mice. We also expect that Azeliragon, despite not reversing collagen glycation, will inhibit the deleterious effects on vascular reactivity and stiffness that the possible co-activation of RAGE will cause. Clarifying these questions will reveal new mechanisms that explain the increased risk of cardiovascular disease associated with diabetes and will open doors to new therapeutic strategies to reduce the cardiovascular risk of diabetic patients. (AU)