Kids with obesity have lower levels of the mitochondrial peptide MOTS‑C, and this drop goes hand‑in‑hand with poorer blood‑vessel health. The study suggests MOTS‑C might help protect the lining of blood vessels, especially when weight is high.

The increasing prevalence of obesity in children and its associated risk with cardiovascular diseases demand more discovery of the novel biomarkers for developing new treatment options for this complex disease. This study aimed to investigate the association of serum MOTS-C (a peptide encoded in the mitochondrial genome) levels and vascular endothelial function in obese children. A total of 225 obese children (aged 8.1 &#xb1; 2.6 years) and 218 healthy children (aged 7.9 &#xb1; 2.2 years) were enrolled. Related anthropometric assessment and biochemical evaluation were done in all subjects. Reactive hyperemia index (RHI), as assessed by the peripheral arterial tonometry, was used for evaluation of peripheral endothelial function. Enzyme-linked immunosorbent assay (ELISA) was used to measure the level of serum MOTS-C. Levels of serum MOTS-C and RHI were lower in the obese children compared with the healthy children (<i>P</i> &lt; 0.01). The RHI level was independently associated with body mass index, high-density lipoprotein cholesterol, and MOTS-C in linear regression analysis. Further analysis showed a significant mediating effect of MOTS-C on the correlation between body mass index and RHI in children, with the ratio of mediating effect value of 9.12%. These data identify that MOTS-C is a previously unknown regulator in the development process of obesity-induced vascular changes.