The influence of the cardiovascular system congenital pathology on the kidneys juxtaglomerular cells differentiation in childhood

Congenital heart defects in children have a significant influence on the state and functions of other body systems, in particular, the urinary system. The kidneys, performing the endocrine function, regulate arterial pressure by the juxtaglomerular apparatus. The aim of the study was to determine the influence of congenital heart defects on the formation of the juxtaglomerular apparatus of the paracortical nephrons in childhood. The objects of the study were of 20 kidney autopsies cases aged from 2 months to 6 years, who were divided into 6 groups by age and the presence or absence of cardiovascular pathologies. The preparations were fixed in neutral 10% formalin, embedded in paraffin, stained with hematoxylin and eosin. Polyclonal primary antibodies to renin were used for immunohistochemical analysis. The sections were used to determine the cross-sectional area of the renal corpuscle, the cross-sectional area of the juxtaglomerular cells, and the degree of renin expression in the juxtavascular cells. The most active growth of the renal corpuscles of the nephrons is observed after 1 year of life, while in patients with cardiovascular malformations, their hypertrophy is noted. The area of the juxtaglomerular cells in the groups without pathologies also increases with age, and in the groups with heart malformations, it increases even more intensively. The revealed dynamics indicate that congenital malformations of the cardiovascular system, causing circulatory disorders, increased blood pressure, involve the juxtaglomerular apparatus of the kidney in the pathogenesis, leading to an increase in the area of rennin-producing cells. Not only the juxtaglomerular cells located in the walls of the afferent arterioles, but also the juxtavascular cells of the vascular glomerulus contribute to the overall level of secreted renin. In early childhood, the area of juxtaglomerular cells increases, while renin expression in juxtavascular cells decreases. In cardiovascular pathology of child, both the area of juxtaglomerular cells and the degree of renin expression by juxtavascular cells increase, which undoubtedly increases the overall level of renin in the body.