Plasma PAI-1 levels in obese children - Effect of weight loss and influence of PAI-1 promoter 4G/5G genotype

An association between an increase in plasminogen activator inhibitor type 1 (PAI-1) and obesity, and also between elevated levels of PAI-1 and the pr esence of PAI-1 promoter 4G allele has been described in adults and can con tribute to increased risk of cardiovascular disease. It has also been sugge sted that in adults a decrease in adiposity has beneficial effects on the h aemostatic system. However, less information is available regarding adiposi ty and fibrinolysis in children. The aim of the present study is to evaluat e the effect of weight loss and the influence of the PAI-1 promoter 4G/5G g enotype on the fibrinolytic system and lipid parameters in obese children. The clinical groups included 102 obese children and 105 controls of similar age and sex distribution. A significant decrease in fibrinolytic activity due to a significant increase in PAI-I antigen and activity levels was obse rved 1. in the obese children in comparison with the control group. In obes e children, no significant differences in PAI-1 levels between the PAI-1 4G /5G genotypes were obtained. A significant correlation was observed between PAI-1 antigenic and functional levels and body mass index (BMI), as well a s between PAI-1 levels and both triglyceride and insulin levels. No correla tion between PAI-1 levels and either cholesterol or glucose levels was obse rved. After a three-month period of treatment to reduce weight, an increase in fi brinolytic activity due to a decrease in PAI-1 levels was observed in the o bese children who had reduced their BMI in comparison with the group of obe se children who did not show a decrease in their BMI. No significant differ ences between the two groups with respect to the variations in tissue type plasminogen activator and fibrinogen levels were obtained after three month s of intervention to reduce weight. A significant correlation was observed between variations in BMI and variations in PAI-1 levels, and a significant inverse correlation was also observed between previous PAI-1 levels and va riation in PAI-1 levels. Therefore, the largest decrease in PAI-1 levels wa s observed in the obese children with the highest previous PAI-1 levels. In conclusion, a decrease in BMI in obese children shows a favourable effec t on the fibrinolytic system due to a decrease in PAI-1 levels. However, no influence of 4G/5G genotype on PAI-1 levels was observed.