L. Di Renzo, A. Bertoli, M. Bigioni, V. Del Gobbo, M. G. Premrov, V. Calabrese, N. Di Daniele and A. De Lorenzo Pages 2699 - 2706 ( 8 )
Insulin resistance and obesity are intimately related to a chronic low grade systemic inflammation. Interleukin- 6 (IL-6) may influence the pathogenesis of obesity-related diseases. The aim of this study is to investigate the effect of bodys fat mass on the relationships between -174G/C IL-6 promoter gene polymorphism, IL-6 circulating level and insulin resistance. A population of 150 Caucasian women was studied, subdivided according to their body composition in non-obese (NW), Normal Weight Obese (NWO) and preobese-obese (OB). The NWO subjects were found in an intermediate position between the NW and OB subjects in terms of body weight, fat mass percentage (FM%), abdominal FAT%, hs-CRP and plasma triglyceride level. Fasting plasma IL-6 concentration was positively correlated with the homeostasis model assessment for insulin resistance (HOMA-IR) in all subjects analyzed (P=0.0014). In NWO and OB women a significantly increased IL-6 mean value was observed compared with NW subjects. In G/G population, the IL-6 plasma level of NWO and OB was significantly higher with respect to NW. No significant differences of IL-6 concentrations were observed in the three groups carrying G/C genotype. NWO and OB women homozygous for the allele C have significantly lower value of IL-6 with respect to NW subjects. IL-6 concentration was positively correlated with FM% in G/G (R2=0.397, P < 0.001) and was negatively correlated in C/C (R2=0.459, P=0.002). No significant correlation was observed in G/C genotype (R2=0.041, P=0.173). In conclusion our study confirms that, at least in Italian Caucasian females, the FM% is a major determinant of an increase in IL-6 production and insulin resistance. -174 G/C IL-6 promoter polymorphism represents a marker which could help to identify, time in advance, “vulnerable” individuals at risk of age and obesity related diseases.
IL-6 -174 G/C promoter polymorphism,obesity,insulin resistance,body composition,obesity related diseases
, , , , , , , Department of Neuroscience, Division of Human Nutrition University of Tor Vergata, Via Montpellier 1, I-00133 Rome, Italy and I.N.Di.M., National Institute for Mediterranean Diet and Nutrigenomic, Reggio Calabria, Italy.