Mid-regional-pro-adrenomedullin plasma levels are increased in obese adolescents

Recently, adrenomedullin (ADM) was defined as a new member of the adipokine family. ADM secreted by adipocytes, through its vasodilator and antioxidant actions, might be protective against metabolic syndrome-associated cardiovascular complications. The aim of the study was to assess plasma mid-regional (MR)-proADM levels in obese adolescents compared to normal-weight subjects and its relation with BMI, body composition and metabolic indices.

Plasma MR-proADM was measured in 32 healthy adolescents [BMI z-score (mean ± SEM) = 0.6 ± 0.09 and 0.8 ± 0.07 in females and males, respectively] and in 51 age-matched obese adolescents [BMI z-score (mean ± SEM) = 2.8 ± 0.12 and 2.9 ± 0.08 in female and males, respectively] by a time-resolved amplified cryptate emission technology assay.

Plasma MR-proADM levels resulted significantly higher in obese than in normal-weight adolescents (MR-proADM: 0.33 ± 0.1 vs 0.40 ± 0.1 nmol/L, p < 0.0001). Using univariate analysis, we observed that MR-proADM correlated significantly with BMI z-score (p < 0.0001), fat mass (p < 0.0001), circulating insulin (p < 0.004), HOMA-IR (p < 0.005), total cholesterol (p < 0.03) and LDL-cholesterol (p < 0.05). Including MR-proADM as response variable and its significant correlates into a multiple regression analysis, we observed that fat mass (p = 0.014) and BMI z-score (p = 0.036) were independent determinants of circulating MR-proADM.

Our study shows for the first time that obese adolescents have higher circulating levels of MR-proADM compared with normal-weight, appropriate controls suggesting its important involvement in obese patients.