Involvement of leptin in the association between percentage of body fat and cardiovascular risk factors.
OBJECTIVE
Recent epidemiologic studies have shown that obesity is associated with elevated blood concentrations of prothrombotic-proinflammatory factors and markers of endothelial dysfunction such as fibrinogen, C-reactive protein (CRP), von Willebrand factor (vWF), and homocysteine. We have assessed whether these markers are associated with percentage of body fat (BF), insulin sensitivity as well as with leptin concentrations.


METHODS
Twenty-five men aged 49.6 +/- 12.7 yr (mean +/- SD) underwent whole-body air displacement plethysmography (Bod-Pod(R)) for estimating BF. Blood analyses for leptin and several other metabolic and cardiovascular markers were carried out.


RESULTS
Obese subjects had higher levels as compared to controls of BF (37.5 +/- 5.1 vs. 26.0 +/- 6.6, p < 0.01), fibrinogen (3.30 +/- 0.43 vs. 2.67 +/- 0.11, p < 0.01), vWF (136.4 +/- 50.4% vs. 81.6 +/- 12.6%, p < 0.05), and leptin (17.6 +/- 8.7 vs. 6.2 +/- 3.3, p < 0.01), lower concentrations of HDL-cholesterol (1.09 +/- 0.20 vs. 1.51 +/- 0.10, p < 0.001) and lower QUICKI (1/[log(Ins(0)) + log(Glu(0))]) (0.31 +/- 0.03 vs. 0.34 +/- 0.02, p < 0.05). No significant changes were observed in CRP (5.7 +/- 3.4 vs. 3.8 +/- 1.6, p = 0.327) and homocysteine (9.4 +/- 4.2 vs. 8.3 +/- 0.9, p = 0.749). A positive correlation was observed between BF and fibrinogen (r = 0.67, p = 0.0003). Plasma leptin concentrations were correlated with fibrinogen (r = 0.71, p = 0.0001) and CRP (r = 0.43, p = 0.044). After adjustment for BF leptin emerged as a significant predictor of fibrinogen (beta = 0.47, p = 0.023; R(2) = 0.59, p < 0.001). QUICKI was positively correlated with HDL-cholesterol (r = 0.59, p = 0.010) and negatively with fibrinogen (r = -0.53, p = 0.025), CRP (r = -0.52, p = 0.028) and vWF (r = -0.56, p = 0.013).


CONCLUSIONS
Increased BF and impaired insulin sensitivity are associated with increased concentrations of cardiovascular risk factors. Leptin seems to be involved in this elevation and emerges as a predictor of circulating fibrinogen concentrations.
Metabolic Research Laboratory, Clínica Universitaria de Navarra, Pamplona, Spain. jagomez@unav.es
Javier
J
Gómez-Ambrosi
Javier
J
Salvador
Jose A
JA
Páramo
Josune
J
Orbe
Jokin
J
de Irala
Alberto
A
Diez-Caballero
María J
MJ
Gil
Javier A
JA
Cienfuegos
Gema
G
Frühbeck
D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000503:physiopathology; D002784:Cholesterol / Q000031:analogs & derivatives / Q000097:blood; D005340:Fibrinogen / Q000032:analysis; D005947:Glucose / Q000378:metabolism; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000503:physiopathology; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood; D014841:von Willebrand Factor / Q000032:analysis
D020738:Leptin; D014280:Triglycerides; D014841:von Willebrand Factor; D006710:Homocysteine; D005340:Fibrinogen; D002097:C-Reactive Protein; D002784:Cholesterol; D005947:Glucose