As mice get older, their bodies make less of a peptide called MOTS-c, especially in muscles and blood—and when they fast, levels drop too, hinting that this peptide responds to energy needs.
Scientific Claim
In mice, endogenous MOTS-c levels in skeletal muscle and plasma decline with age and are reduced during fasting, suggesting that MOTS-c expression is metabolically regulated and may contribute to age-related metabolic decline.
Original Statement
“MOTS-c levels in skeletal muscle and in circulation decline concomitantly with the development of insulin resistance during aging in mice... fasting lowered endogenous expression of MOTS-c in certain metabolically active and mitochondria-rich tissues (skeletal muscle and testes) as well as in plasma.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study reports natural variations in MOTS-c levels across age and feeding states without intervention, making 'decline' and 'reduced' appropriate associative verbs.
Evidence from Studies
Supporting (1)
The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance
The study shows that a tiny molecule from mitochondria (MOTS-c) helps mice stay metabolically healthy as they age, and giving more of it fixes age-related problems—suggesting that losing this molecule over time might cause those problems.