Human albumin and its modifications in emergency medicine

Relevance. Human albumin (HA) accounts for 60% of all plasma proteins and is an important component of extracellular fluids, including lymph, interstitial and cerebrospinal fluid. This protein has multifunctional properties — it supports oncotic blood pressure, regulates the immune system, stabilizes the endothelium and affects key pathophysiological mechanisms. The aim of the review is to determine the features of the structure, properties and use of HA in acute medicine with a primary focus on brain damage of hypoxic-traumatic origin. Literature was searched in the databases PubMed, Google Academic, Web of Science, RSCI by keywords: human albumin, critical conditions, brain hypoxia, reactive oxygen species and nitrogen, search depth of 10 years. An analysis of data on the structure and modifications of HA in hypoxia/ischemia under conditions of increased formation of reactive oxygen species (ROS) and nitrogen (RNS) is presented. The informative value of HA modifications (“ischemia–modified albumin” — IMA and albumin oxidized by RNS from tyrosine — 3-nitrotyrosine — 3-HT residues) in the diagnosis and prognosis of various diseases is considered. One of the limitations of the use of HA in critical condition medicine is the lack of knowledge of the mechanisms of action of HA and modifications of endogenous and exogenous (injected) HA during infusion therapy. In the reduced state, HA has antioxidant activity and can neutralize the action of ROS and RNS formed during hypoxia. However, under conditions of hypoxia/ischemia and oxidative/nitrosative stress, HA is susceptible to oxidation and modification, which leads to the loss of its protective properties.