Relationship between plasminogen activator inhibitor-1 antigen, leptin, and fat mass in obese children and adolescents

Hyperleptinemia may be associated with cardiovascular risk and is linked with parameters of fibrinolytic processes in adults. We studied whether body fatness, leptin, and insulin interact with plasminogen activator inhibitor-1 antigen (PAI-1-Ag) and tissue-type plasminogen activator antigen (tPA-Ag) in obese children and adolescents. Twenty-three boys (mean +/- SD: age, 10.7 +/- 3.3 years; body mass index BMI], 28.7 +/- 5.4 Kg/m2) and 19 girls (age, 11.9 +/- 2.7 years; BMI, 29.4 +/- 4.8 Kg/m2) were investigated. Body fat mass (FM) in the children was calculated by bioelectrical impedance analysis, and blood samples were obtained for leptin, insulin, C-peptide, PAI-1-Ag, and tPA-Ag. The children were divided into 3 subgroups according to maturation. Maturity was associated with greater adiposity and higher levels of leptin and C-peptide, but insulin and PAI-1-Ag were not different between prepubertal, pubertal, and late/postpubertal children. PAI-1-Ag was associated with leptin and insulin, but not after adjustment for fatness. PAI-1-Ag was independently associated with tPA-Ag (r = .36, P < .02). Multiple regression analysis showed that tPA-Ag failed to reach the level of significance (P = .07), but FM contributed to the variation in PAI-1-Ag (adjusted R2 = .29). The BMI was the main determinant for the variation in leptin (adjusted R2 = .386) and in insulin (adjusted R2 = .60, all P < .001). Neither gender, maturation, chronological age, or leptin contributed significantly to the variation in either PAI-1-Ag or tPA-Ag. Our data suggest that adiposity and other variables contribute to higher levels of PAI-1-Ag. Leptin seems not to be independently linked with fibrinolytic parameters, but an unfavorable metabolic and fibrinolytic risk profile might emanate from the obese pubertal stage.