Hypothesis: The potential therapeutic role of nicorandil in COVID-19

Therapeutic potential of nicorandil beyond anti-anginal drug: A review on current and future perspectives

Nicorandil (NIC) is a well-known anti-anginal agent, which has been recommended as one of the second-line treatments for chronic stable angina as justified by the European guidelines. It shows an efficacy equivalent to that of classic anti-anginal agents. NIC has also been used clinically in various cardiovascular diseases such as variant or unstable angina and reperfusion-induced damage following coronary angioplasty or thrombolysis. Different mechanisms have been involved in the protective effects of nicorandil in various diseases, including opening of adenosine triphosphate-sensitive potassium (KATP) channel and donation of nitric oxide (NO). In recent years, NIC has been found to show numerous pharmacological activities such as neuroprotective, nephroprotective, hepatoprotective, cardioprotective, and testicular protective effects, among other beneficial effects on the body. The present review dwells on the pharmacological potentials of NIC beyond its anti-anginal action.

Nicorandil mitigates amiodarone-induced pulmonary toxicity and fibrosis in association with the inhibition of lung TGF-β1/PI3K/Akt1-p/mTOR axis in rats

The long-term side effect of the antiarrhythmic drug, amiodarone (AMIO), such as lung toxicity, remains a critical clinical issue. The previous knowledge denotes diverse antioxidant, anti-inflammatory, and antifibrotic properties of the anti-anginal drug, nicorandil (NI). Therefore, we aimed to investigate the possible protective effect of NI on pulmonary tissue remodelling following AMIO-induced lung toxicity. The included rats were assigned into four equal groups (n = 8): (1) control, (2) control group that received NI 10 mg kg^-1  day^-1 , (3) model group that received AMIO in a dose of 60 mg kg^-1  day^-1 , and (4) treated group (AMIO-NI) that were treated with AMIO plus NI as shown above. Drug administration continued for 10 weeks. AMIO resulted in deteriorated (p < 0.001) pulmonary functions accompanied by respiratory acidosis. AMIO showed an obvious histological injury score with intense collagen deposition, disturbed nitric oxide synthase enzymes (NOS/iNOS), and increased alpha smooth muscle actin expression. Furthermore, AMIO upregulated the transforming growth factor (TGF-β1)/phosphoinositide-3 kinase (PI3K)-Akt1-p/mammalian target of rapamycin (mTOR) axis, which determined the possible mechanism of AMIO on pulmonary remodelling. NI treatment significantly (p < 0.001) prevented the AMIO-induced lung toxicity, as well as inhibited the TGF-β1/PI3K/Akt1-p/mTOR axis in the lung tissue of rats. The results were confirmed by an in-vitro study. CONCLUSION: The current results revealed that NI was effective in preserving the lung structure and functions. Amelioration of the oxidative stress and modulation of TGF-β1/PI3K/Akt1-p/mTOR have been achieved. This study suggests NI administration as a preventive therapy from the serious pulmonary fibrosis side effect of AMIO.

Managing endothelial dysfunction in COVID-19 with statins, beta blockers, nicorandil, and oral supplements: A pilot, double-blind, placebo-controlled, randomized clinical trial

Coronavirus disease 2019 (COVID-19) is associated with endothelial dysfunction. Pharmacologically targeting the different mechanisms of endothelial dysfunction may improve clinical outcomes and lead to reduced morbidity and mortality. In this pilot, double-blind, placebo-controlled, randomized clinical trial, we assigned patients who were admitted to the hospital with mild, moderate, or severe COVID-19 infection to receive, on top of optimal medical therapy, either an endothelial protocol consisting of (Nicorandil, L-arginine, folate, Nebivolol, and atorvastatin) or placebo for up to 14 days. The primary outcome was time to recovery, measured by an eight category ordinal scale and defined by the time to being discharged from the hospital or hospitalized for infection-control or other nonmedical reasons. Secondary outcomes included the composite outcome of intensive care unit (ICU) admission or the need for mechanical ventilation, all-cause mortality, and the occurrence of side effects. Of 42 randomized patients, 37 were included in the primary analysis. The mean age of the patients was 57 years; the mean body mass index of study participants was 29.14. History of hypertension was present in 27% of the patients, obesity in 45%, and diabetes mellitus in 21.6%. The median (interquartile range) time to recovery was not significantly different between the endothelial protocol group (6 [4-12] days) and the placebo group (6 [5-8] days; p value = 0.854). Furthermore, there were no statistically significant differences in the need for mechanical ventilation or ICU admission, all-cause mortality, or the occurrence of side effects between the endothelial protocol group and the placebo group. Among patients hospitalized with mild, moderate, or severe COVID-19 infection, targeting endothelial dysfunction by administering Nicorandil, L-arginine, Folate, Nebivolol, and Atorvastatin on top of optimal medical therapy did not decrease time to recovery. Based on this study's findings, targeting endothelial dysfunction did not result in a clinically significant improvement in outcome and, as such, larger trials targeting this pathway are not recommended.

Combination of mesenchymal stem cells and nicorandil: an emerging therapeutic challenge against COVID-19 infection-induced multiple organ dysfunction

The recent COronaVIrus Disease (COVID)-19 pandemic has placed an unprecedented burden on the drug development opportunity to prevent the onset of multi-organ failure.

Emerging experimental reports have highlighted the beneficial effects of mesenchymal stem cell (MSC) administration against COVID-19. MSCs and their derived exosomes may attenuate SARS-CoV-2-induced inflammatory response through managing the immune cell function and cytokine expression. Although these are promising results, the exposure of MSCs to chemical compounds with pharmacological activities may further improve their homing, survival, and paracrine machinery.

Nicorandil (N-[2-hydroxyethyl]-nicotinamide nitrate), an established adenosine triphosphate-sensitive potassium channel opener, is recently hypothesized to modulate inflammation as well as cell injury and death in COVID-19-affected lungs through inhibiting reactive oxygen species levels and apoptosis. Since it also exerts protective effects against hypoxia-induced MSC apoptosis, we assumed that transplanted MSCs combined to long-term nicorandil administration may survive longer in a severely inflamed microenvironment and have more beneficial effects in the treatment of SARS-CoV-2 infection than MSCs alone.