Investigation of the consequences of persistent platelet activation in long COVID on platelet cell death mechanisms and their clearance by efferocytosis

• Grant number: 24/18379-0
• Support Opportunities: Scholarships in Brazil - Program to Stimulate Scientific Vocations
• Start date: March 17, 2025
• End date: May 06, 2025
• Field of knowledge: Biological Sciences - Immunology - Cellular Immunology
• Principal Investigator: Larissa Dias da Cunha
• Grantee: João Pedro Ribeiro Soares dos Santos
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Long COVID is a disease characterized by the persistence of symptoms after the acute phase of COVID-19, lasting for weeks, months, or even years. Recent studies from our group have shown that thromboinflammatory mechanisms present in COVID-19, such as platelet activation and hyperresponsiveness, persist during long COVID following a severe case. However, none have demonstrated that these mechanisms occur after a mild case. Therefore, our team is studying the persistence of platelet activation and responsiveness in long COVID patients. The ingestion and degradation of dead and dying cells, a process known as efferocytosis, by macrophages is an important component of their functional programming in infectious diseases, including COVID-19. Our hypothesis is that the platelets of long COVID patients are undergoing increased apoptosis and may alter the function of macrophages that phagocytize them. In this context, we propose using a model of platelet stimulation with thrombin that mimics the characteristic hyperresponsiveness of the platelets in long COVID patients, based on results already obtained in our studies.