Inflammation and age-associated skeletal muscle deterioration (sarcopaenia)

Abstract

SummaryAgeing is accompanied by chronic inflammatory responses due to elevated circulatory inflammatory cytokine production. Several inflammatory cytokines have been shown to be responsible for a decrease in muscle mass. However, little is known about the possible relationship between inflammation and sarcopaenia. This review aims to summarise the existing evidence about inflammation and sarcopaenia. Sarcopaenia is defined as an age-related decrease of muscle mass and/or muscle strength; it is caused by multiple factors, such as skeletal muscle atrophy, neuromuscular junction degeneration, hormone imbalance, cytokine imbalance, protein synthesis and proteolysis. Several inflammatory cytokines have been considered to promote muscle loss; C-reactive protein levels are significantly upregulated in sarcopaenia and sarcopenic obesity, and high levels of interleukin-6 are associated with reduced muscle mass and muscle strength (the administration of interleukin-6 could lead to a reduction in muscle mass). Up-regulation of tumour necrosis factor-α expression is also related to the development of sarcopaenia. Signalling pathways, such as protein kinase B/mammalian target of rapamycin, Janus kinase/signal transducer and activator of transcription-5 and signal transducer and activator of transcription 3 signalling, involved in muscle metabolism are regulated by insulin-like growth factor-1, tumour necrosis factor-α and interleukin-6 respectively. In conclusion, the inflammatory cytokines produced during chronic inflammation due to ageing, may influence their respective related pathways, thus leading to age-related muscle deterioration.The translational potential of this articleThis review can provide more information for sarcopaenia medicine research in terms of anti-inflammation therapy.

Fruit and Vegetable Consumption and Sarcopenia among Older Adults in Low- and Middle-Income Countries

“…The inverse association between fruit consumption and sarcopenia observed in our study may be explained by the effects of antioxidant nutrients such as vitamin C and carotenoids [35], which are found in abundance in fruits [13]. The mechanisms of aging of skeletal muscle are related with factors such as increases in circulating cytokines (e.g., interleukin-6, tumour necrosis factor-α, interleukin-10, interleukin-15) [36] and production of reactive oxygen species, which can cause direct cellular damage of skeletal muscle fibers and DNA, and also have negative effects on synthesis of protein [37]. It is possible that exogenous antioxidant vitamins have potential importance for maintaining skeletal muscle mass especially in old age as endogenous antioxidant efficiency is reduced as people age [38].…”

Low alanine aminotransferase levels predict low muscle strength in older patients with diabetes: A nationwide cross‐sectional study in Korea

“…There are multiple factors that can contribute to sarcopenia pathogenesis other than the behavioral factors of low physical activity, aging and undernutrition. These include impairment of neurophysiological functions, a decline in sex hormones and growth hormones, an imbalance between muscle‐cell growth enhancers and suppressors, increased muscle protein turnover, and increased pro‐inflammatory cytokines . In patients with diabetes, the progression of chronic inflammation, oxidative stress and vascular complications results in deterioration of muscle protein turnover and muscular atrophy/apoptosis …”

“…These include impairment of neurophysiological functions, a decline in sex hormones and growth hormones, an imbalance between muscle-cell growth enhancers and suppressors, increased muscle protein turnover, and increased pro-inflammatory cytokines. 16,17 In patients with diabetes, the progression of chronic inflammation, oxidative stress and vascular complications results in deterioration of muscle protein turnover and muscular atrophy/apoptosis. 18 The deterioration of ALT levels are mainly due to the following: (i) hepatic causes, such as hepatitis B, hepatitis C, alcohol intake and NAFLD; and (ii) non-hepatic causes, such as metabolic disorders.…”

Inflammatory Potential of the Diet and Risk of Sarcopenia and its Components

“…It seems that additional information are required to shed light on the link between dietary in ammatory index and individual components of sarcopenia, given that there is a possible association between in ammation and sarcopenia, as indicated in a recent meta-analysis [5]. Low-grade chronic in ammation seems to predispose elderly people to muscle loss and dysfunction through affecting muscle proteolysis and myocyte apoptosis [30,31]. Therefore, it is logical to expect nding and association between in ammatory potential of the diet and sarcopenia and its components.…”