5. Conclusion
Symptomatic COVID-19 patients develop renal complications and patients with pre-existing renal conditions also have a high chance of disease progression and mortality. Currently, there are no approved drugs that offer renal protection in COVID-19 patients although a number of vaccines have been approved by FDA for emergency use. With a new viral pandemic which has significant renal involvement, there is a need for future studies to determine the risk factors of kidney disease among COVID-19 patients. It is important to also determine the link between genetic polymorphisms and the risk of developing kidney diseases among certain races of people including those of African ancestry, who have genetic polymorphisms to kidney diseases, and to know whether there is an association between APOL1 high-risk carriers and risk of developing COVID-19-associated nephropathy. As the search for pharmacological agents for effective treatment of COVID-19 is underway, there are studies that are suggesting the potential clinical use of H2S donors, as these agents fall under all three classifications of COVID-19 treatment - antiviral treatment, cytokine storm treatment, and thrombosis treatment. A growing body of evidence show that H2S donors interact with ACE2, TMPRSS2 and other potential SARS-CoV-2 receptors on the host cell surface, alter SARS-CoV-2 membrane, thereby inhibiting the entry of the virus into the host cell and consequently preventing its replication (assembly and release). This mechanism is thought to suppress SARS-CoV-2-induced inflammatory pathway, leading to organ protection (Fig. 2). Other studies also suggest inhibition of gene transcription by H2S donors along with antiviral immunosuppressive effect. In the light of these mechanisms of the antiviral action of H2S donors, more experimental and clinical studies with H2S donors, especially those that are already FDA-approved and are in human clinical trials such as STS, NAC, ATB-346 and zofenopril, should be considered for preventive treatment or effective therapy against COVID-19 infection, and should include their use in nebulizer for aerosol inhalation into the lungs and dissemination to extra-pulmonary organs such as the kidney.