L-carnitine as a novel approach for pain and inflammation relief in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by joint inflammation, largely mediated by pro-inflammatory cytokines. Considering the established involvement of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway and transforming growth factor-beta1 (TGF-β1) in RA, this research aimed to assess efficacy and safety of L-carnitine as an adjunct therapy targeting these pathways. Forty-six patients with active RA were randomly divided into two equal groups. Group1 (control group) received disease-modifying antirheumatic drugs (DMARDs), including methotrexate, leflunomide, and hydroxychloroquine. Group2 (L-carnitine group) received, DMARDs plus L-carnitine 500 mg twice daily for 12 weeks. A clinical evaluation was conducted, which included tender joint count (TJC), swollen joint count (SJC), pain intensity quantified via the visual analogue scale (VAS), and morning stiffness duration. Additionally, the Disease Activity Score in 28 joints (DAS28) and functional capability as measured by a modified health assessment questionnaire (MHAQ) were assessed. Laboratory evaluation included C-reactive protein (CRP), STAT3, and TGF-β1 measurement. All evaluations were executed both at baseline and following a 12-week treatment period. After 12 weeks, the L-carnitine group showed significant improvement in morning stiffness, VAS, TJC, CRP, DAS28, and MHAQ compared to baseline. While no significant within-group changes were observed in STAT3, TGF-β1 in the L-carnitine group, STAT3 levels increased significantly in the control group compared to baseline. In conclusion, L-carnitine in combination with DMARDs may enhance clinical outcomes in RA by mitigating systemic inflammation. Nevertheless, its impact on STAT3 and TGF-β1 remains unclear and warrants further research.