Correlation of intestinal flora diversity, inflammatory factors and insulin resistance in elderly patients with type 2 diabetes mellitus

Abstract

Objective To investigate the correlation of intestinal flora diversity, inflammatory factors and insulin resistance in elderly patients with type 2 diabetes mellitus (T2DM). Methods Totally 80 elderly patients with T2DM were selected as the T2DM group, and 80 healthy subjects were enrolled as the control group. The Bacteroides, Prevotella, Lactobacillus, Bifidobacterium and Enterobacteriaceae were detected, and homeostasis model assessment-insulin resistance (HOMA-IR) was calculated in the two groups. The interleukin 6 (IL-6), IL-10, IL-22, tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) were measured and compared between them. Pearson correlation analysis was used to analyze the relationship of different intestinal flora with HOMA-IR and inflammatory factors in elderly T2DM patients. Results Compared to the control group, the amount of Bacteroides [(10.0 ± 0.5) logN/g vs. (8.1 ± 0.9) logN/g] and Enterobacteriaceae [(9.86 ± 0.27) logN/g vs. (7.05 ± 0.19) logN/g] was significantly higher (t = 3.162, 3.016; both P < 0.05), and the amount of Prevotella [(7.22 ± 0.27) logN/g vs. (9.35 ± 0.39) logN/g], Lactobacillus [(5.12 ± 0.25) logN/g vs. (7.67 ± 0.43) logN/g] and Bifidobacterium [(7.2 ± 0.4) logN/g vs. (11.0 ± 0.5) logN/g] was significantly lower in the T2DM group (t = 5.230, 4.163, 7.115; all P < 0.05). The levels of HOMA-IR [(6.4 ± 0.8) vs. (3.1 ± 0.4)], IL-6 [(154 ± 15) ng/L vs. (81 ± 10) ng/L], IL-22 [(628 ± 36) ng/L vs. (106 ± 11) ng/L], TNF-α [(208 ± 23) ng/L vs. (118 ± 11) ng/L] and IFN-γ [(136 ± 15) ng/L vs. (76 ± 13) ng/L] were significantly higher (t = 7.156, 3.167, 5.026, 3.557, 2.134; all P < 0.05), and the IL-10 level [(127.7 ± 18.7) ng/L vs. (376.8 ± 1.8) ng/L] was significantly lower in the T2DM group than in the control group (t = 2.272, P < 0.05). The correlation analysis showed that there were positive correlations between Prevotella, Enterobacteriaceae and HOMA-IR (r = 0.613, 0.437; both P < 0.05), and negative correlations between Bacteroides, Lacto-bacillus, Bifidobacterium and HOMA-IR (r = -0.617, -0.526, -0.575, -0.616; all P < 0.05). The Bacteroides, Prevotella, Lactobacillus and Bifidobacterium were negatively correlated to IL-6 (r = -0.617, -0.526, -0.575, -0.616; all P < 0.05), IL-22 (r = -0.636, -0.587, -0.621, -0.573; all P < 0.05), TNF-α (r = -0.593, -0.633, -0.476, -0.539; all P < 0.05) and IFN-γ (r = -0.475, -0.538, -0.602, -0.573; all P < 0.05), and positively correlated to IL-10 (r = 0.535, 0.623, 0.459, 0.506; all P < 0.05). Enterobacteriaceae was positively correlated to IL-6, IL-22, TNF-α and IFN-γ (r = 0.437, 0.599, 0.576, 0.518; all P < 0.05), and negatively correlated to IL-10 (r = -0.518, P < 0.05). Conclusion The association between intestinal flora and insulin resistance in elderly T2DM patients suggests that its mechanism may be related to the level of inflammatory factors. Key words: Aged; Diabetes mellitus, type 2; Intestinal flora; Inflammatory factors; Insulin resistance