Proinflammatory cytokines and cardiac abnormalities in uncomplicated obesity: Relationship with abdominal fat deposition

Background and aim: Obesity can be considered a state of chronic, low-grade inflammation. Particularly, visceral adipose tissue (VAT) seems to be an active compartment in pro-inflammatory molecule secretion. The possible existence of a correlation between circulating cytokines, their soluble receptors, abdominal fat accumulation and echocardiographic abnormalities in uncomplicated obesity was investigated. Methods and results: Echocardiographic parameters, C-reactive protein (CRP), interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6-R), tumor necrosis factor-α (TNF-α) and soluble TNF receptor I (TNFR-I) were assessed in 27 normotensive obese women (age 33.3 ± 8.3 years; BMI 43.5 ± 4.8 kg/m²) and 15 normal-weight controls (age 36.8 ± 8.2 years; BMI 22.6 ± 1.7 kg/m²). VAT was assessed by CT. The obese patients had higher serum IL-6 (p <0.01), sIL-6-R (p <0.0001), sIL-6-R/IL-6 complex (p <0.05), TNF-α (p <0.02), sTNF-α-RI (p <0.03) and CRP (p <0.0001) levels than normal women. Moreover, end-diastolic septum thickness (SW), end-diastolic posterior wall thickness (PW), absolute and indexed left ventricular mass, deceleration time (DT), myocardial performance index (MPI) and isovolumetric relaxation time (IVRT) were correlated with sIL-6-R, sIL-6-R/IL-6 complex and CRP levels. Interestingly, sIL-6-R, sIL-6-R/IL-6 complex, CRP, SW, PW, DT and MPI were higher in patients with a VAT area >130 cm² than those with 2. Conclusion: In normotensive obese women several pro-inflammatory molecules correlate with both echocardiographic abnormalities and the amount of intra-abdominal fat; these results may support a role for visceral fat in predisposing to cardiac dysfunction, possibly through a low-grade state of inflammation.