Exogenous Pyruvate in Defense Against Human-Exposure Toxicants: A Review of In Vitro and In Vivo Evidence

Pyruvate is an alpha-keto acid that occurs naturally in living cells. It is a key metabolite in cellular respiration and a substrate for the synthesis of glucose (in gluconeogenesis) and certain amino acids. Exogenous pyruvate, for example in the form of sodium pyruvate or ethyl pyruvate, has potential therapeutic applications due to its antioxidant and anti-inflammatory properties. This review summarises cell culture and animal studies that report the cytoprotective effects of exogenous pyruvate compounds during exposure to environmental pollutants, drugs, UV radiation, and burns. These reports show that the main mechanisms through which exogenous pyruvate exerts its beneficial effects are the neutralisation of reactive oxygen species, protection and stabilisation of mitochondria, maintenance of ATP levels, and inhibition of inflammatory signalling pathways, including the nuclear factor-kappa B (NF-κB) pathway. The article also outlines potential challenges associated with the therapeutic use of exogenous pyruvate. These include the instability of inorganic pyruvate (sodium pyruvate) and the fact that the metabolism of ethyl pyruvate differs between humans and animals.