DISCUSSION
rheumatoid arthritis, non-alcoholic fatty liver disease, death, obese, TNF-α, muscle mass, sarcopenic, sarcopenia, lobular inflammation, weight loss
RHEUMATOID ARTHRITIS, OBESE, SARCOPENIA, NON-ALCOHOLIC FATTY LIVER DISEASE
The study yielded to several important findings. Firstly, it has been observed that patients with sarcopenia exhibit elevated levels of inflammatory cytokines such as TNF-α, IL-1β, and IL-6. However, interventions involving nutrition support and exercise have shown promising results in significantly reducing the aforementioned elevated cytokines.In the present study, four kinds of inflammatory cytokines were examined, encompassing TNF-α, IL-1β, IL-6 and IL-15. TNF-α, primarily produced by macrophages and monocytes, initiates cellular apoptosis, regulates non-specific immune responses to counteract the spread and growth of infectious pathogens. Moreover, TNF-α acts as a strong inducer of nuclear factor kappa B (NF-κB), which plays a pivotal role in activating multiple pro-inflammatory genes within the cell nucleus. However, excessive and prolonged production of TNF-α can have detrimental effects, such as inducing joint destruction in patients with rheumatoid arthritis [In our study, three (TNF-α, IL-1β, and IL-6) of four cytokines we examined revealed elevated in sarcopenic patients compared with the controls. An animal study using the sarcopenic mice model found that TNF-α contributed to sarcopenia by mediating pyroptosis, one type of programmed cell death, through activating the pathways of caspase-8 and caspase-3 [However, our research findings revealed no significant increase in IL-15 levels among patients with sarcopenia compared to the non-sarcopenic controls. Interestingly, we observed that exercise and nutritional interventions resulted in elevated IL-15 levels in the sarcopenic patients. A study involving 160 older adults provided insights into our results, demonstrating that control subjects had significantly higher levels of IL-15 compared to individuals with sarcopenia [A notable discovery has been made regarding the reduction of TNF-α, IL-1β, and IL-6 levels following exercise and nutritional support in individuals diagnosed with sarcopenia. While the positive effects of exercise on diminishing pro-inflammatory cytokines have been observed in various populations, there has been limited research exploring the relationship between exercise and pro-inflammatory cytokines specifically in patients with sarcopenia. Koh et al. conducted a RCT to examine the effect of 4-week moderate intensity walking exercise on 27 obese patients [We speculated moderate-to-high intensity exercise could reduce pro-inflammatory cytokine in the sarcopenic patients through several possible mechanisms. Regular exercise plays a significant role in reducing body fat, which is often elevated in individuals with sarcopenia. Adipocytes are a prominent source of pro-inflammatory cytokines. However, exercise-induced reduction in pro-inflammatory cytokines can occur independently of weight loss [In the present study, we hypothesized that nutrition supplements could potentially contribute to the reduction of circulating pro-inflammatory cytokines. A recent review has highlighted amino acids as endogenous metabolite modulators that may be beneficial in reducing lobular inflammation in non-alcoholic fatty liver disease [In our current study, we observed a notable improvement in grip strength and muscle mass following a combined nutrition and exercise intervention. This finding aligns with the existing body of evidence supporting the efficacy of such interventions in treating sarcopenia. For instance, a comprehensive network meta-analysis conducted in 2021 [The present study has several limitations that should be acknowledged. Firstly, in the control group where no intervention was administered, we did not periodically assess their pro-inflammatory cytokine levels. Without a reference group for comparison, it is possible that the changes observed in cytokine levels among sarcopenic patients might have occurred as part of a natural recovery process. Secondly, the blood samples were collected within one week after the cessation of exercise training and nutritional support, preventing us from determining the duration of the post-intervention anti-inflammatory effect in our study. Thirdly, there are other imaging modalities for evaluating muscle mass in the diagnosis of sarcopenia, besides DXA. In recent years, ultrasound imaging has gained prominence as a muscle mass measurement tool [