A systematic review of preclinical studies on the efficacy of taurine for the treatment of rheumatoid arthritis.

Due to the undesirable effects of conventional medical therapies prescribed for rheumatoid arthritis (RA), complementary therapies, especially nutritional agents, have recently gained great attention. Recent animal and in vitro researches have shown benefits of taurine (Tau), a sulfur-containing amino acid, in RA and suggest that Tau may be a therapeutic candidate in RA; however, no systematic review exists regarding Tau and RA. Accordingly, this paper systematically reviewed the available researches regarding Tau and RA and plausible underlying mechanisms. We searched electronic databases like Scopus, WOS, PubMed, Embase, ProQuest, Cochrane Library, and a search engine Google Scholar until December 2020 and we have applied search alert services to detect related papers published after the primary search. We did not have any restriction in publication date and/or language. We found no clinical study; thus we considered related animal and in vitro researches. Furthermore, we checked the citations or references of these researches and grey literature to detect possible studies. We did not consider reviews, book chapters, conference abstracts, and articles about Tau in health problems other than RA. Eighteen articles were entered in present systematic review. Animal and in vitro researches showed that Tau either directly or indirectly (via Tau derivatives such as Tau-chloramine, Tau-bromamine, taurochenodeoxycholic acid, and taurolidine) could control RA by different mechanisms such as reducing inflammation, suppressing oxidative stress, and inducing apoptosis. This review serves convincing clues about the efficacy of Tau in RA and explains the importance of additional clinical investigations.