Inflammatory biomarkers in type 2 diabetic patients: effect of glycemic control and impact of LDL subfraction phenotype.

Background: Type 2 diabetes mellitus (T2D) is associated with higher cardiovascular risk partly related to an increase in inflammatory parameters. The aim of this study was to determine the association of inflammatory biomarkers with low-density lipoprotein (LDL) subfraction phenotype and glycemic control in subjects with T2D and poor glycemic control.

Methods: A cross-sectional study was performed comparing 122 subjects with T2D (59 ± 11 years old, body mass index 30.2 ± 5.6 kg/m2) with 54 control subjects. Patients with T2D were classified according to their LDL subfraction phenotype and inflammatory biomarkers (C-reactive protein, Interleukin-6, Interleukin-8, Transforming growth factor β1, Monocyte chemotactic protein 1, Leptin, Adiponectin) were evaluated according to the degree of glycemic control, LDL phenotype and other clinical characteristics. Forty-two subjects with T2D were studied before and after 3 months of improving glycemic control by different strategies.

Results: Patients with T2D had higher C-reactive protein (CRP) and monocyte chemotactic protein-1 (MCP1) levels and lower adiponectin concentration, compared to controls. T2D subjects with body mass index ≥ 30 kg/m2 had higher CRP levels (5.2 ± 4.8 mg/l vs 3.7 ± 4.3 mg/l; p < 0.05). The presence of LDL phenotype B was related to higher levels of transforming growth factor-β1 (TGF-β1) (53.92 ± 52.82 ng/l vs 31.35 ± 33.74 ng/l; p < 0.05) and lower levels of adiponectin (3663 ± 3044 ng/l vs 2723 ± 1776 ng/l; p < 0.05). The reduction of HbA1c from 9.5 ± 1.8% at baseline to 7.4 ± 0.8% was associated with a significant reduction of TGF-β1 (41.86 ± 32.84 ng/l vs 26.64 ± 26.91 ng/l; p = 0.02).

Conclusions: Subjects with T2D, especially those with LDL phenotype B and obesity, have higher levels of inflammatory biomarkers. Improvement of glycemic control reduces TGF-β1 levels, which may contribute partly to its renoprotective role.