Function of Hemoglobin in individuals with Secondary Erythrocytosis

• Grant number: 23/05188-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2023
• End date: June 30, 2024
• Field of knowledge: Health Sciences - Medicine - Pathological Anatomy and Clinical Pathology
• Principal Investigator: Susan Elisabeth Domingues Costa Jorge
• Grantee: João Vitor Giorgete Braga Andrade
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 19/18886-1 - Pathophysiological mechanisms and treatment of red blood cell abnormalities, AP.TEM

Abstract

Human hemoglobin (Hb) is a protein in red blood cells that carries oxygen from the lungs totissues. The affinity of this protein for oxygen is affected by various factors, and the properbalance of this binding is crucial for its function. Variants of Hb with increased affinity cancause secondary erythrocytosis, a condition where there is excessive production of red bloodcells with high Hb content due to tissue hypoxia. Various other causes can result in secondaryerythrocytosis. However, several cases remain unresolved. This is understood, for example,in two cases referred to the Hemoglobinopathies Laboratory at the Department of Pathology(Faculty of Medical Sciences / Unicamp) for investigation of the presence of variant Hbs withincreased affinity for O2. Despite classical causes of polycythemia being ruled out (absenceof variant Hbs), functional studies of Hb revealed alterations in Hb-O2 binding. Forinvestigation, these samples were subjected to mass spectrometry, which detected thepresence of four phosphate-derived compounds, in addition to normal Hb. In order toelucidate if there are other non-classical modulators that may alter Hb-O2 affinity andoccasionally result in secondary erythrocytosis, this study aims to characterize the function ofHb in 15 cases referred for investigation of variant Hbs. This study, according to our research,might be pioneering as relating and involving functional aspects of Hb in secondaryerythrocytosis therefore it may contribute to the elucidation of this clinical manifestation.This study will have the collaboration of the Centro Infantil Boldrini and Hospital IsraelitaAlbert Einstein, which also have cases of secondary erythrocytosis to be clarified.