Relationships between parameters of nitrogenous metabolites and HRV in humans exposed to the factors of the accident at the Chоrnobyl Nuclear Power Plant

Abstract

Background. We have previously shown that nitrogenous metabolites have immunomodulatory effects, both suppressor and enhancing, both in healthy rats and in humans exposed to pathogenic influences. The immunomodulatory effect of bilirubin is probably mediated through aryl hydrocarbon receptors, and uric acid through TL- and adenosine receptors of immune cells. The question of mediators of the immunomodulatory action of urea and creatinine remains open. We hypothesized the mediating role of mediators of the autonomic nervous system and adaptation hormones. The aim of this study is to analyze the relationships between the parameters of nitrogenous metabolites, on the one hand, and HRV markers of the parameters of the autonomic nervous system - on the other hand. Material and methods. The object of observation in 1997 were 19 men and 3 women who were exposed to pathogenic factors of the accident at the Chоrnobyl nuclear power plant during the liquidation of its consequences in 1986-87. The survey was conducted twice - on admission and after two weeks of rehabilitation at the Truskavets’ Spa. The plasma and urinary concentration of the nitrogenous metabolites were determined. The state of the autonomic nervous system (ANS) was judged by the HRV parameters recorded before and after submaximal bicycle ergometric loading. Results. Both negative and positive metabolic-ANS correlations were revealed. Calculation of multiple correlation coefficients between individual metabolite parameters and constellations of HRV parameters revealed the maximum vegetotropic effect of Urea plasma (R=0,700) and Uric acid urine (R=0,623). This is followed by Urea urine (R=0,531) and Creatinine plasma (R=0,457). No significant correlations were found for Creatinine urine, Uric acid plasma and Bilirubinemia. The canonical correlation between the constellation of nitrogenous metabolites, on the one hand, and the HRV markers of ANS, on the other hand, was strong: R=0,747; χ²₍₂₈₎=63; p<10^-3. Conclusion. Previously identified immunomodulatory effects of urea and creatinine are realized, possibly through cholinergic and adrenergic mechanisms.