Response of fractional synthesis rate (FSR) of fibrinogen, concentration of D-dimer and fibrinolytic balance to physical activity-based intervention in obese children.
BACKGROUND
Physical activity-induced reduction in obesity-related hyperfibrinogenemia in children has been reported. The underlying mechanisms remain elusive. Further, the effect of such interventions on fibrinolysis in children is scarce.


OBJECTIVE
To investigate in obese children, before and after a physical activity-based intervention: (i) the mechanistic role of fractional synthesis rate (FSR) of fibrinogen in the reduction of hyperfibrinogenemia; and (ii) the changes in fibrinolytic factors.


METHODS
Subjects included 21 (age > 14 < 18 years; Tanner stage, IV-V) children (15 obese, BMI >95%tile for age and sex and six lean, BMI <85%tile). After baseline measurements of FSR of fibrinogen, and concentrations of fibrinogen, D-dimer, PAI-1 and t-PA in all children, studies were repeated after a 3-month randomized controlled physical activity-based lifestyle intervention in obese children only.


RESULTS
FSR of fibrinogen was higher (P = 0.002) in the obese (vs. lean) group, which was reduced (P = 0.001) after intervention. This almost completely accounted for the reduction in obesity-related hyperfibrinogenemia. High levels of D-dimer decreased (P = 0.001) after intervention, whereas fibrinolysis was not enhanced.


CONCLUSIONS
The direct reduction in the FSR of fibrinogen and the remarkable correlation between the magnitudes of reduction in fibrinogen FSR and concentration signify a mechanistic role for FSR in the regulation of physical activity-induced reversal of hyperfibrinogenemia in obese children. The congruent reductions in the FSR of fibrinogen and the concentrations of fibrinogen and D-dimer in response to intervention despite depressed fibrinolysis suggest an overall improvement in the hypercoagulable state in obese children with physical activity-based lifestyle intervention.
Nemours Childrens Clinic, Jacksonville, FL 32207, USA. bbalagop@nemours.org
P
P
Balagopal
D
D
George
S
S
Sweeten
K J
KJ
Mann
H
H
Yarandi
N
N
Mauras
D E
DE
Vaughan
D000293:Adolescent; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D005340:Fibrinogen / Q000096:biosynthesis*; D005342:Fibrinolysis; D006801:Humans; D007700:Kinetics; D008019:Life Style; D008297:Male; D009765:Obesity / Q000097:blood* / Q000150:complications / Q000628:therapy*; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D012307:Risk Factors; D013927:Thrombosis / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D010959:Tissue Plasminogen Activator / Q000097:blood
D005338:Fibrin Fibrinogen Degradation Products; D017395:Plasminogen Activator Inhibitor 1; C051321:SERPINE1 protein, human; C036309:fibrin fragment D; D005340:Fibrinogen; D010959:Tissue Plasminogen Activator