The relationship between the gut microbiota shifts and the inflammatory biomarkers in obese and normal weight adults

Abstract

Background:Healthy obesity means obese individuals remain free of metabolic health complications. Several researches link microbiota changes to obesity, focus on metabolic role of IL-6 and its ability to alter fat metabolism and correlate circulating calprotectin concentration to morbid obesity. This study evaluated the relative abundance of gut microbiota (Prevotella and γ-Proteobacteria), estimated the serum levels of inflammatory mediators (IL-6 and calprotectin) and studied the correlation between them in healthy obese and normal weight adults. Methods: 33 healthy obese (HO) and 14 normal weight (NW) controls were included. Serum levels of IL-6 and calprotectin were estimated by ELISA. Abundances of Prevotella and γ-Proteobacteria were determined in stool using real time PCR. Results: IL-6 and calprotectin levels were significantly lower in HO than in NW (p=0.001, p=0.001 respectively) with significant negative correlation between IL-6 and body mass index (BMI) in HO (r=-0.438, p=0.011) and negative but statistically insignificant correlation with BMI in NW groups (r=-0.024, p=0.935). There was negative but statistically insignificant correlation between calprotectin and BMI in HO (r=-0.075, p=0.677) and NW (r=-0.381, p=0.179). Prevotella and γ-Proteobacteria abundances were higher in HO than in NW and insignificant (p=0.31, p=0.55 respectively) with significant positive correlation between Prevotella and γ-Proteobacteria abundance in HO (r=0.436, p=0.011), positive and insignificant correlations between abundance of Prevotella and levels of IL-6 in HO and NW (r=0.303, P=0.086 vs r=0.316, p=0.272 respectively). Conclusion: IL-6 and calprotectin have role in regulation of energy homeostasis. Elevated abundances of Prevotella and γ-Proteobacteria may be the primary shifts in gut microbiota of  HO.