Relationship of collagen as the component of the extracellular matrix with the mechanisms of autonomic regulation of the cardiovascular system under simulated conditions of long-term isolation.

The study of proteins - potential markers, associated signal transduction pathways, and their targets - provides a new understanding of the fundamental mechanisms occurring at the level of regulatory processes in the cardiovascular system (CVS), especially in space flight, as well as in model experiments that reproduce its individual effects on the human body. The article presents the results of studies in an experiment with 120-day isolation within the framework of the SIRIUS project in which 6 volunteers aged 28 to 44 years (three men and three women) participated. SIRIUS (Scientific International Research in Unique Terrestrial Station) is the international research project, which studies the issues of biomedical and psychological support of long-term manned space flights. The possible involvement of collagen different types, an extracellular matrix protein, in the mechanisms of autonomic regulation of the CVS was studied. Using chromatic mass spectrometry in urine samples and analysis of heart rate variability, we have established that the extracellular matrix collagen, which is present, in particular, in the structure of the blood vessel wall, are markers associated with the modulating effect of the autonomic nervous system on the regulatory mechanisms of blood circulation. We hypothesized that these proteins may be a biomarker of the autonomic balance in the regulatory mechanisms of the circulatory system. In addition, these proteins can also be markers of the aging process, which increases the risks of developing autonomic dysfunction of the cardiovascular system (dominance of sympathicotonia) and changes in the quality of the tissue of the heart muscle and blood vessels, provoking the development of prenosological conditions and diseases of the cardiovascular system.

[Age features of heart rate variability in cosmonauts according to urine proteomics data.]

As the life of the International Space Station (ISS) is lengthening, Russian crews are dominated by cosmonauts over 40 years of age who have repeatedly made a space flight (SF) and have a long stay on the ISS. In order to study the age-related features of the regulation of heart rate variability (HRV) in cosmonauts, based on proteomics data, we analyzed simultaneously the obtained data on the proteomic composition of urine samples and electrocardiogram (ECG) parameters, followed by an analysis of heart rate variability (HRV) in cosmonauts in the age group of 46,5±3,4 (n=12). The survey was carried out in the period of preparation for the next flight. The urine proteome was studied by mass spectrometry and analyzed by bioinformatic methods. Heart rate variability was assessed by software methods for analyzing ECG fragments. For the first time, data based on proteomics on the age-related features of the regulation of heart rate variability in cosmonauts are presented. According to age periodization, cosmonauts are in the middle age of the second period. The concentrations of mucin 1, type VI collagen, and cadherin 13 were shown to change with age. A decrease in HRV was also observed with increasing age. There was an increase in sympathetic influence and a progressive decrease in parasympathetic influence.