Effect of Weight Loss on Proinflammatory State of Mononuclear Cells in Obese Women

In order to investigate whether weight loss can lead to improvement of the mononuclear cell (MNC) proinflammatory state, 21 nondiabetic obese women with mean age 34 ± 2 years (mean ± s.e.m.) and BMI 32.5 ± 1.2 kg/m2 were enrolled in a 12‐week caloric restriction and light exercise‐based weight loss program. Ten lean women served as controls. Reverse transcription‐PCR of proinflammatory cytokines and adipocytokines as well as homeostasis model assessment of insulin resistance (HOMA‐IR) were determined before and after weight reduction. Nuclear factor κB (NF‐κB) binding to DNA and inhibitors of NF‐κB (IκB‐α and IκB‐β) obtained from peripheral MNCs were measured. Overall, subjects lost a mean of 4.0 ± 0.4 kg (5.0 ± 0.3% of their initial body weight) (P < 0.01). In addition to significant reductions in BMI, fasting glucose and insulin concentrations, mean serum high‐sensitivity C‐reactive protein (hs‐CRP), migration inhibitor factor (MIF), leptin and visfatin levels decreased by 49.0, 66.6, 17.2, and 50.2%, respectively (all P < 0.05), while adiponectin concentrations rose by 33.9% (P < 0.05). The DNA binding of the transcriptionally active NF‐κB from (p65/p50) decreased by 38.1% (P < 0.05). Elevated levels of mRNA of NF‐κB related proinflammatory genes, tumor necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), MIF, and matrix metalloproteinase‐9 (MMP‐9), decreased significantly after weight loss. Although mRNA expression of Rel‐A, p105, IκB‐α, IκB‐β decreased significantly, their protein levels did not change after weight loss. As a group, NF‐κB binding activity correlated with HOMA‐IR (r = 0.332, P = 0.049) and marginally with values of BMI (r = 0.308, P = 0.059). In conclusion, weight loss by 5% of initial weight in nondiabetic obese women led to significant improvement in activated intranuclear NF‐κB binding as well as several transcriptions of proinflammatory genes regulated by NF‐κB.