Mitochondrial Dysfunction and Intrinsic Capacity: Insights From a Narrative Review

Mitochondrial dysfunction occurs during aging and may play a role, by distinct mechanisms, in the loss of intrinsic capacity (IC), operationalized through 5 domains: locomotion, psychological, cognition, vitality/nutrition, and sensory (hearing, vision). The objective of this review is to provide an overview of the associations between mitochondrial function and IC domains. This study is a narrative review of original investigations (any study design) on the relationship of mitochondrial function in humans with locomotion (eg, gait speed), psychological (eg, depressive symptoms), cognition (eg, global cognitive function), vitality (eg, handgrip strength), and/or sensory (hearing and vision acuity) domains. The IC domains were considered from the perspective of the Integrated Care for Older People (ICOPE), according to the World Health Organization guidelines. The results show that there is still limited evidence regarding the associations between mitochondrial function and IC domains. Most studies were cross-sectional and involved small samples. The tissues/cells most often investigated in the original studies were skeletal muscle and peripheral blood mononuclear cells. The available evidence, although limited, indicates that mitochondrial function, in particular, the mitochondrial DNA copy number, is associated with all IC domains. The evidence is more robust for locomotion and less abundant for hearing. In conclusion, this review supports the notion that mitochondrial function is correlated with IC domains by distinct mechanisms. Future studies are needed to confirm whether mitochondria play a role in maintaining optimal function and preventing/delaying the onset of disability during aging, which could ultimately contribute to healthy aging.