The severity and outcome of Covid-19 depend on the various activities of the renin-angiotensin-aldosterone system, level of the opioid growth factor, [met5]-enkephalin and pre-existing comorbidities.

Objective: Aim: The aim of the study was evaluation of the methionine-enkephalin in patients with severe COVID-19 with various activities of the renin-aldosterone system in comparison with COVID-19 patients with pre-existing comorbidities (renal cell cancer, critical limb ischemia) and adverse pregnancy outcomes..

Patients and methods: Materials and Methods: To test our hypothesis, this case-control study consisted of 20 healthy donors (control group); 49 patients with a positive diagnosis of COVID-19 according to PCR analysis; 15 patients with a positive diagnosis of COVID-19 in combination with renal cell cancer; 29 patients with a positive diagnosis of COVID-19 in combination with critical limb ischemia, 10 pregnant womens with COVID-19. Methionine-enkephalin, plasma renin activity, plasma aldosterone was measured by radioimmunoassay. Statistical and graphical analyses were done using Statistica 7.0 StatSoft software and using MedCalc.

Results: Results: As our results have shown, hyperreninemia against the background of hypoaldosteronism and inhibition of enkephalinergic activity is fatal for COVID-19 patients. In COVID-19 patients with renal cell carcinoma, met-enkephalin, aldsterone, and plasma renin activity also showed a high predictive value for mortality. Whereas in patients with critical limb ischemia the strongest predictor biomarkers of mortality were only renin plasma activity. In conditions of physiological hyperreninemia during pregnancy, met-enkephalin acts as a biomarker for preterm birth, and in pregnant patients with COVID-19, plasma renin activity acts as such a biomarker.

Conclusion: Conclusions: We found that in different categories of patients with COVID-19, the severity and outcome depend on the different activity of the renin-angiotensinaldosterone and enkephalinergic systems.