Inhaled nitric oxide: can it serve as a savior for COVID-19 and related respiratory and cardiovascular diseases?

Abstract

Nitric oxide (NO), as an important gaseous medium, plays a pivotal role in the human body, such as maintaining vascular homeostasis, regulating immune-inflammatory responses, inhibiting platelet aggregation, and inhibiting leukocyte adhesion. In recent years, the rapid prevalence of coronavirus disease 2019 (COVID-19) has greatly affected the daily lives and physical and mental health of people all over the world, and the therapeutic efficacy and resuscitation strategies for critically ill patients need to be further improved and perfected. Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator, and some studies have demonstrated its potential therapeutic use for COVID-19, severe respiratory distress syndrome, pulmonary infections, and pulmonary hypertension. In this article, we describe the biochemistry and basic characteristics of NO and discuss whether iNO can act as a "savior" for COVID-19 and related respiratory and cardiovascular disorders to exert a potent clinical protective effect.

Keywords: COVID-19; acute respiratory distress syndrome; inhaled nitric oxide; lung infection; nitric oxide; pulmonary arterial hypertension.

Figure 1

The biosynthesis and biological functions of NO. eNOS, nNOS, and iNOS catalyze the production of NO through L-arginine and perform different biological functions in the human body. eNOS mediates vasodilatation and inhibits platelet aggregation, leukocyte adhesion, smooth muscle cell proliferation, and atherosclerosis. nNOS, in addition to regulating the release of neurotransmitters, increases the development of cardiac and renal insufficiency and hypertension when NO production decreases. iNOS can produce large amounts of NO when stimulated, which on the one hand helps to enhance the ability of antibacterial and inflammatory responses and on the other hand can have adverse effects on normal tissues. (By Figdraw).

Figure 2

Potential clinical applications of iNO in respiratory and cardiovascular diseases. iNO can be used as a “rescue” or “innovative” therapy for COVID-19-related respiratory and cardiovascular diseases, with potential clinical benefits in hypoxemia, pulmonary infections, dilated pulmonary vessels, myocardial injury, cardiac arrest, and pulmonary hypertension. The potential clinical benefits of these therapies in hypoxemia However, high-quality evidence for these clinical applications is still lacking and needs to be explored and refined. (By Figdraw).