Plasma angiotensin peptides as biomarkers of rheumatoid arthritis are correlated with anti-ACE2 auto-antibodies level and disease intensity

BACKGROUND: This study aimed to explore a correlation between plasma angiotensin II/(1–7) (Ang II/Ang-(1–7)) ratio, anti-ACE2 autoantibodies level and disease activity in rheumatoid arthritis (RA) patients. METHODS: In a pilot study, the plasma level of Ang II, Ang-(1–7), and anti-ACE2 autoantibodies of twelve RA patients (five in active stage and seven in remission) were measured using an LC–MS/MS method and an ELISA kit, respectively. RESULTS: The Ang-(1–7) level was significantly higher in the remission group than in the active RA patients (7.63 ± 2.61 vs. 1.29 ± 0.81 ng/mL). On the contrary, the Ang II level was higher in those with active RA compared to the remission group (5.43 ± 1.82 vs. 0.87 ± 0.16 ng/mL). The mean ELISA score of anti-ACE2 autoantibodies in patients with active RA was significantly higher than patients in remission (1.41 ± 0.11 vs. 1.81 ± 0.11, p < 0.05). CONCLUSION: This study result suggests that the angiotensin peptides concentration and anti-ACE2 autoantibodies levels can be used as biomarkers of RA. This will help clinicians evaluate better treatment success rates and disease prognosis to prevent long-term complications of RA.