Hemoglobins in ischemic brain damage: from fetal hemoglobin to neuroglobin

Introduction. This review is devoted to the study of the structure, properties, evolution of hemoglobins, biochemical and clinical aspects of the use of neuroglobin (Ngb) and fetal hemoglobin (HbF) in health and in ischemic hypoxia of the brain. Material and methods. To search for relevant literature, we used the eLibrary, MedLine and ScienceDirect databases from 2000 to 2023. The data on Ngb and HbF are analyzed, mainly concerning the issues of diagnostics and treatment of hypoxic lesions of the central nervous system. Results. The review begins with the structural organization of penta- and hexacoordinated hemoglobins. The evolution of hemoglobin genotypes from bacterial hemoproteins, currently represented by the Ngb protein, to the evolutionarily youngest HbF of placental mammals is presented. The diversity of hemoglobins allows us to assume that the transport function of vertebrate hemoglobins appeared relatively recently during adaptation to the increasing concentration of oxygen in the atmosphere, and the most ancient functions of hemoglobins should be enzymatic (utilization of NO and oxygen) and sensory (in relation to oxygen). Ngb is found in brain tissue, retina, some endocrine glands of mammals and humans. Functions of Ngb: participation in NO metabolism, detoxification of active oxygen species (ROS), protection from apoptosis, signal transmission, participation in lipid metabolism. As for HbF, the physicochemical properties of this hemoglobin have been studied for quite a long time, and a broader clinical study of Ngb and HbF in various pathologies is associated with the problem of diagnostic test systems for these hemoproteins. Conclusion. Ngb is a promising drug for protecting cells from hypoxia and neuronal death, and Ngb-based drugs can find application in a variety of medical fields. As for HbF, the development of ELISA for HbF in blood hemolysates opens up new prospects for diagnosing hypoxic and ischemic central nervous system lesions.