MMP1 and rheumatoid arthritis: According to the results of another study, the abundance of Eubacterium ventriosum group, Ruminococcus_1, Family_XIII, and Coprococcus was negatively linked with the risk of rheumatoid arthritis, suggesting that these specific gut microbiota can increase matrix metallo-proteinase (MMP)-1, MMP-3, and MMP-13 expression, as well as OC activity to aggravate cartilage and bone damage (35).