In this article, we propose that differences in COVID-19 morbidity may be associated
with transient receptor potential ankyrin 1 (TRPA1) and/or transient receptor potential
vanilloid 1 (TRPV1) activation as well as desensitization. TRPA1 and TRPV1 induce
inflammation and play a key role in the physiology of almost all organs. They may
augment sensory or vagal nerve discharges to evoke pain and several symptoms of COVID-19,
including cough, nasal obstruction, vomiting, diarrhea, and, at least partly, sudden
and severe loss of smell and taste. TRPA1 can be activated by reactive oxygen species
and may therefore be up-regulated in COVID-19. TRPA1 and TRPV1 channels can be activated
by pungent compounds including many nuclear factor (erythroid-derived 2) (Nrf2)-interacting
foods leading to channel desensitization. Interactions between Nrf2-associated nutrients
and TRPA1/TRPV1 may be partly responsible for the severity of some of the COVID-19
symptoms. The regulation by Nrf2 of TRPA1/TRPV1 is still unclear, but suggested from
very limited clinical evidence. In COVID-19, it is proposed that rapid desensitization
of TRAP1/TRPV1 by some ingredients in foods could reduce symptom severity and provide
new therapeutic strategies.
