Interleukin 6, Matrix Metalloproteinase-8 and Tissue Inhibitor-1 Levels in Obesity

Abstract

Obesity is a nutritional disease characterized by excess of adipose tissue. It is recognized as a low-grade chronic inflammation state characterized by increased serum levels of acute phase proteins such as interleukins (ILs) and cytokines. IL-6 is a proinflammatory cytokine, which is involved in the regulation of lipid metabolism associated with obesity and inflammation. It plays numerous proinflammatory roles. However, IL-6 may also play an anti-inflammatory role. Matrix metalloproteinases (MMPs) participate in several physiological processes such as remodeling of extracellular matrix (ECM), healing, angiogenesis and apoptosis. They are regulated by specific tissue inhibitors (TIMPs) which block access to the active site of MMPs. A dual role for MMP-8 has been described under specific conditions: MMP-8 plays a role in the development of the inflammatory response but appears to play an anti-inflammatory role during recovery and may be crucial for this process. Aims:To determine the IL-6, MMP-8 and TIMP-1 levels and compare the results between 3 groups of individuals (between 26 and 65 years): normal weight (n=8), overweight (n=11) and obese (n=22). Material and Methods:The semi-quantification of IL-6, MMP-8 and TIMP-1 was performed through the slot blot technique. Results:The levels of MMP-8 and IL-6 were higher in the group of overweight individuals than in the normal weight group and in the obese group, but the differences were not statistically significant. TIMP-1 levels were slightly elevated in the group of normal weight individuals and in the group of obese individuals, in relation to the group of overweight individuals, however the differences were not statistically significant. There was also a moderate positive correlation between glycemic levels and the percentage of visceral fat mass (p<0.0001) and between serum levels of MMP-8 and serum levels of IL-6 (p<0.05). Discussion and Conclusion:The significant correlation between IL-6 levels and the percentage of visceral fat mass may be related to the fact that adipose tissue is endocrine and produce numerous factors contributing to systemic inflammation. The moderate positive correlation between serum MMP-8 levels and serum IL-6 levels may indicate that these can be stimulated by the same mechanisms in the inflammation process.