Plasma visfatin and tumor necrosis factor-alpha (TNF-α) levels in metabolic syndrome

Experimental studies have shown that tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) downregulate visfatin gene expression in adipocytes. On the other hand, the induction of cytokine production by visfatin in leucocytes and monocytes has also been described.

To assess the possible interrelation between plasma concentrations of visfatin and TNF-α and TNF soluble receptor in obese women fulfilling, or not, the criteria of metabolic syndrome (MS).

Ninety two obese women were included in the study. Metabolic syndrome, based on IDF criteria (2005) was diagnosed in 71 subjects (mean age 53 ± 9 years; body mass index 39.1 ± 5.6 kg/m(2), waist circumference 109.6 ± 11.4 cm). The remaining 21 formed the non-MS subgroup (mean age 52 ± 9 years, body mass index 36.3 ± 5.2 kg/m(2), waist circumference 104.7 ± 11.0 cm). Fourteen healthy normal weight women served as controls. In all subjects, body composition was assessed by the bioimpedance method.

In the MS subgroup, but not in the non-MS subgroup, visfatin levels were significantly higher than in controls. We did not observe any significant difference in plasma concentrations of visfatin, TNF-α or sTNFRs between the MS subgroup and the non-MS subgroup. Only in the MS subgroup and in the combined analysis of all study subgroups did plasma visfatin concentrations correlate significantly with TNF-α levels (R = 0.31, p = 0.01, R = 0.21, p = 0.03; respectively). Additionally, in the MS subgroup there was a positive correlation between visfatin levels and insulin resistance (R = 0.53, p = 0.01).

Our findings suggest that visfatin in metabolic syndrome should be regarded as a proinflammatory factor indirectly favouring the development of insulin resistance.