Divergent immunometabolic changes in adipose tissue and skeletal muscle with ageing in healthy humans

Abstract

Ageing is associated with increased systemic inflammation and metabolic dysfunction that contributes to the development of age-associated diseases. The role of adipose tissue in immunometabolic alterations that take place with ageing is unknown in humans. We show in healthy, active and lean older adults that adipose tissue-but not skeletal muscle-displays considerable pro-inflammatory transcriptomic, cellular, and secretory changes, and a reduction in insulin signalling proteins compared to younger adults. These findings indicate that adipose tissue undergoes substantial immunometabolic alterations with ageing, and that these changes are tissue-specific and more profound than those observed in skeletal muscle or in the circulation. These results identify adipose tissue as an important tissue in the biological ageing process in humans, which may exhibit signs of immunometabolic dysfunction prior to systemic manifestation.

Altered immunometabolism in adipose tissue: A major contributor to the ageing process?

“…In a recent issue of The Journal of Physiology , Trim et al . (2021) explored the immunometabolic changes in abdominal subcutaneous adipose tissue, skeletal muscle and blood with age by comparing young (27 ± 4 years) and older (66 ± 5 years) physically active males without obesity (Fig. 1).…”

“…Immunometabolic changes with ageing in blood, skeletal muscle and subcutaneous adipose tissue reported by Trim et al . (2021). ↑, Increased compared to young adults.…”

“…Trim et al . (2021) identified numerous changes within adipose and skeletal muscle tissues with ageing, which could further be associated with the ageing process. Immunological differences were examined with the use of flow cytometry.…”

“…Their results showed that T‐cells, granulocytes and macrophages were all elevated with age in skeletal muscle, whereas only T‐cells and granulocytes were elevated in adipose tissue (Trim et al . 2021). Increased macrophage and T‐cell levels have been directly implicated in the inflammatory pathways associated with ageing, leading to insulin resistance and eventual metabolic diseases (Tam et al .…”

“…In addition to changes in immune cell content, Trim et al . (2021) compared inflammatory profiles of blood and adipose tissue secretions. A greater number of inflammatory cytokines were elevated with age in adipose tissue secretions than in the blood, suggesting that these cytokines are primarily acting locally within adipose tissue.…”