Role of irisin and myostatin on sarcopenia in malnourished patients diagnosed with GLIM criteria

Potential effect of Irisin on sarcopenia: a systematic review

OBJECTIVE

Sarcopenia, a progressive musculoskeletal disorder associated with aging, is characterized by the deterioration of muscle mass, strength, and physical performance. This condition significantly increases the risk of debilitating consequences including functional impairment, diminished life quality, and increased mortality. With the progress of aging, it will affect a large number of people in the world and bring many problems. Despite its clinical significance, there are no medicine used to treatment sarcopenia by FDA approval in clinical. This systematic review synthesizes current evidence on the diagnostic and therapeutic potential of irisin-a myokine induced by exercise-in sarcopenia, aiming to address two key questions: (1) Can irisin serve as a reliable biomarker for sarcopenia diagnosis? (2) Does irisin hold promise as a therapeutic agent for sarcopenia management?

METHODS

A comprehensive literature search was conducted across multiple databases (Web of Science, PubMed, Cochrane Library, and Embase) to examine the relationship between irisin and sarcopenia. Eligible studies meeting our inclusion criteria underwent rigorous quality assessment.

RESULT

364 studies were identified, of which only 21 met the inclusion criteria-12 involving human studies and 9 involving animal and cell experiments. In human studies, irisin may serve as a potential diagnostic marker for sarcopenia in the elderly and postmenopausal women. In addition, as a myokine of exercise induced, increased circulating levels of irisin may enhanced skeletal muscle mass. Moreover, animal and cellular experiments suggest that increased levels of irisin help improve muscle mass.

CONCLUSION

In conclusion, this review indicates that irisin has potential therapeutic effects for sarcopenia and may become a promising treatment for sarcopenia in the future. However, there is currently a lack of high-quality studies on the use of irisin in treating sarcopenia, and the relevant mechanisms of action are not yet clear. Therefore, more studies are needed to clarify the relationship between irisin and sarcopenia in the future.

Sarcopenia and metabolic dysfunction-associated steatotic liver disease: The role of exercise-related biomarkers

The etiology, risk factors, and management of sarcopenia and metabolic dysfunction-associated steatotic liver disease (MASLD) are comparable, which prompted the investigators to search for a particular diagnostic or prognostic biomarker that was involved in both disorders. Peptides or proteins known as myokines, or exerkines, are produced and secreted by contracted muscles. Myokines work similarly to hormones in their actions. One common clinical hallmark of sarcopenia and MASLD is physical inactivity, which is associated with alterations in the levels of myokines. Irisin is a positive regulator of muscle size that is elevated in the biological fluids during exercise. Significantly low levels were observed in the pathological conditions associated with physical inactivity. The serum levels of irisin are significantly higher in MASLD patients, while their levels were lower in risk factors of MASLD, e.g., diabetes mellitus, obesity, and insulin resistance. In sarcopenia with obesity (sarcopenic obesity) or with a normal build, serum irisin levels are significantly lower than in healthy subjects. Therefore, serial determination of irisin levels that showed a transition from higher to lower levels in MASLD indicated the development of sarcopenia in those patients.

Obesity, Osteoarthritis, and Myokines: Balancing Weight Management Strategies, Myokine Regulation, and Muscle Health

Obesity and osteoarthritis (OA) are increasingly prevalent conditions that are intricately linked, with each exacerbating the other's pathogenesis and worsening patient outcomes. This review explores the dual impact of obesity on OA, highlighting the role of excessive weight in aggravating joint degeneration and the limitations OA imposes on physical activity, which further perpetuates obesity. The role of muscle tissue, particularly the release of myokines during physical activity, is examined in the context of OA and obesity. Myokines such as irisin, IL-6, and myostatin are discussed for their roles in metabolic regulation, inflammation, and tissue repair, offering insights into their potential therapeutic targets. This review emphasizes the importance of supervised weight management methods in parallel with muscle rehabilitation in improving joint health and metabolic balance. The potential for myokine modulation through targeted exercise and weight loss interventions to mitigate the adverse effects of obesity and OA is also discussed, suggesting avenues for future research and therapy development to reduce the burden of these chronic conditions.

Irisin and Its Role in Postmenopausal Osteoporosis and Sarcopenia

Menopause, an extremely delicate phase in a woman's life, is characterized by a drop in estrogen levels. This decrease has been associated with the onset of several diseases, including postmenopausal osteoporosis and sarcopenia, which often coexist in the same person, leading to an increased risk of fractures, morbidity, and mortality. To date, there are no approved pharmacological treatments for sarcopenia, while not all of those approved for postmenopausal osteoporosis are beneficial to muscles. In recent years, research has focused on the field of myokines, cytokines, or peptides secreted by skeletal muscle fibers following exercise. Among these, irisin has attracted great interest as it possesses myogenic properties but at the same time exerts anabolic effects on bone and could therefore represent the link between muscle and bone. Therefore, irisin could represent a new therapeutic strategy for the treatment of osteoporosis and also serve as a new biomarker of sarcopenia, thus facilitating diagnosis and pharmacological intervention. The purpose of this review is to provide an updated summary of what we know about the role of irisin in postmenopausal osteoporosis and sarcopenia.