Muscle wasting in rheumatoid arthritis: The role of oxidative stress

Abstract

Rheumatoid arthritis (RA), the commonest inflammatory arthritis, is a debilitating disease leading to functional and social disability. In addition to the joints, RA affects several other tissues of the body including the muscle. RA patients have significantly less muscle mass compared to the general population. Several theories have been proposed to explain this. High grade inflammation, a central component in the pathophysiology of the disease, has long been proposed as the key driver of muscle wasting. More recent findings however, indicate that inflammation on its own cannot fully explain the high prevalence of muscle wasting in RA. Thus, the contribution of other potential confounders, such as nutrition and physical activity, has also been studied. Results indicate that they play a significant role in muscle wasting in RA, but again neither of these factors seems to be able to fully explain the condition. Oxidative stress is one of the major mechanisms thought to contribute to the development and progression of RA but its potential contribution to muscle wasting in these patients has received limited attention. Oxidative stress has been shown to promote muscle wasting in healthy populations and people with several chronic conditions. Moreover, all of the aforementioned potential contributors to muscle wasting in RA (i.e., inflammation, nutrition, and physical activity) may promote pro- or anti-oxidative mechanisms. This review aims to highlight the importance of oxidative stress as a driving mechanism for muscle wasting in RA and discusses potential interventions that may promote muscle regeneration via reduction in oxidative stress.

Keywords: Rheumatoid arthritis; Oxidative stress; Muscle wasting; Inflammation; Cytokines; Exercise

Core tip: Muscle wasting is common in rheumatoid arthritis (RA) and associates with significant health burden. To date several theories have been proposed to explain why RA patients loose muscle mass but the exact underlying mechanisms are not clear. Oxidative stress is a key driver of muscle wasting in the general population; however, its potential role in muscle wasting in RA has not been studied. As it arises from this review, oxidative stress seems to contribute to muscle wasting in RA. Further research on the subject is warranted, especially focusing on the underlying mechanisms and potential interventions.