Gut Dysbiosis and Muscle Aging: Searching for Novel Targets against Sarcopenia

Abstract

Advanced age is characterized by several changes, one of which is the impairment of the homeostasis of intestinal microbiota. These alterations critically influence host health and have been associated with morbidity and mortality in older adults. “Inflammaging,” an age-related chronic inflammatory process, is a common trait of several conditions, including sarcopenia. Interestingly, imbalanced intestinal microbial community has been suggested to contribute to inflammaging. Changes in gut microbiota accompanying sarcopenia may be attenuated by supplementation with pre- and probiotics. Although muscle aging has been increasingly recognized as a biomarker of aging, the pathophysiology of sarcopenia is to date only partially appreciated. Due to its development in the context of the age-related inflammatory milieu, several studies favor the hypothesis of a tight connection between sarcopenia and inflammaging. However, conclusive evidence describing the signaling pathways involved has not yet been produced. Here, we review the current knowledge of the changes in intestinal microbiota that occur in advanced age with a special emphasis on findings supporting the idea of a modulation of muscle physiology through alterations in gut microbial composition and activity.

Heat-Killed Bifidobacterium breve B-3 Enhances Muscle Functions: Possible Involvement of Increases in Muscle Mass and Mitochondrial Biogenesis

“…Recent studies have suggested that Bifidobacterium is recognized as a key taxon for physical frailty and sarcopenia in elderly individuals [8]; however, it remains unclear whether the decreases in bifidobacterial abundance that occur with age influence muscle health [7,41]. The present study explored the positive relationships between Bifidobacterium and muscle health.…”

Inflammageing: chronic inflammation in ageing, cardiovascular disease, and frailty

“…This theory is supported by studies in animal models, but no definitive evidence exists of increased gut permeability and leakage of pro-inflammatory products in older individuals who are free from overt inflammatory disease 72 . Dysbiosis seems to be more severe in conditions in which prevalence increases with ageing, such as obesity and type 2 diabetes 73 . Of note, changes in gut microbiota composition have been shown to be associated with increased frailty 74–76 , which could be owing to gut dysbiosis-induced inflammation.…”

Impact of Melatonin on Skeletal Muscle and Exercise

“…Thus, factors affecting the inter-individual microbiome such as aging, metabolic diseases, inflammation, cancer, or malnutrition might condition muscle weakness and induce sarcopenia [197][198][199]. Indeed, in age related diseases and obesity, an abnormal intestinal flora, i.e., dysbiosis, was detected [200][201][202]. The analysis of the composition of the intestinal microbiota in the elderly demonstrated that there were more pathogens such as Enterobacteriaceae and scarce butyrate-producing healthy bacteria, leading to less tight junctions in the mucosa and altered permeability [203].…”