The Role of Acidosis in the Pathogenesis of Severe Forms of COVID-19

Simple Summary Recently, several studies have shown that acidosis, which is increased acidity in the blood and other body tissues, is often associated with severe COVID-19. In this article, we look at the mechanisms and consequences of acidosis that can lead to an exacerbation of COVID-19. We want to draw the attention of readers to the threshold values of such disease characteristics as hypoxia and acidosis, which are associated with a sharp deterioration in the patient's condition. Hypoxia and acidosis mutually reinforce each other according to the principle of a vicious cycle (that is, they are involved in a system of positive feedbacks). Elevated blood lactate (lactic acid) levels are associated with poor clinical outcomes in COVID patients. As a practical recommendation, we propose to pay more attention to the prevention of acidosis, including in the early stages of the disease, when the adjustment of homeostasis requires less effort and is less risky. COVID-19 has specific characteristics that distinguish this disease from many other infections. We suggest that the pathogenesis of severe forms of COVID-19 can be associated with acidosis. This review article discusses several mechanisms potentially linking the damaging effects of COVID-19 with acidosis and shows the existence of a vicious cycle between the development of hypoxia and acidosis in COVID-19 patients. At the early stages of the disease, inflammation, difficulty in gas exchange in the lungs and thrombosis collectively contribute to the onset of acidosis. In accordance with the Verigo-Bohr effect, a decrease in blood pH leads to a decrease in oxygen saturation, which contributes to the exacerbation of acidosis and results in a deterioration of the patient's condition. A decrease in pH can also cause conformational changes in the S-protein of the virus and thus lead to a decrease in the affinity and avidity of protective antibodies. Hypoxia and acidosis lead to dysregulation of the immune system and multidirectional pro- and anti-inflammatory reactions, resulting in the development of a cytokine storm. In this review, we highlight the potential importance of supporting normal blood pH as an approach to COVID-19 therapy.

Automated summary

This article summarizes recent studies linking acidosis with severe COVID-19 cases. It highlights the vicious cycle between acidosis and hypoxia in COVID-19 patients, which can exacerbate the condition. The review suggests the importance of supporting normal blood pH in COVID-19 therapy.