Adipose tissue dysfunction serum markers are associated with high density lipoprotein size and glycation in the early stages of type 2 diabetes.

Background: High-density lipoproteins (HDLs) have antiatherogenic properties related to their chemical structure. Adipose tissue (AT) influences HDL reverse cholesterol transport and plasma HDL cholesterol levels. However, whether AT dysfunction affects HDL subpopulations and their glycation in early type 2 diabetes (T2D) is still unknown.

Objective: To investigate the association of inflammation and AT dysfunction serum markers with the size and glycation of HDLs in normoglycemic, prediabetes, and T2D subjects.

Methods: We assessed HDL particle size and advanced glycation end-product (AGE) content in HDLs isolated from normoglycemic (n = 17), prediabetes (n = 17), and recently T2D-diagnosed (n = 18) subjects. Insulin, adiponectin, and plasminogen activator inhibitor 1 (PAI-1) were determined using the Bio-Rad Multiplex Platform, and free fatty acids (FFAs) and high sensitivity C-reactive protein (hs-CRP) were determined by standard procedures. The AT insulin resistance (ATIR) index and ATIR/adiponectin and adiponectin/leptin ratios were calculated.

Results: HDL was progressively smaller (nm) and enriched with AGE (mg-BSA-AGE/mg protein) according to the glucose categories: 8.49 and 7.5 in normoglycemic subjects, 8.44 and 12.4 in prediabetic subjects, and 8.32 and 14.3 in T2D subjects (P = 0.033 and P = 0.009 for size and AGE, respectively). In multivariable regression analysis, the ATIR/adiponectin ratio was inversely associated with HDL size (β = -0.257, P = 0.046), and the ATIR ratio was directly associated with HDL glycation (β = 0.387, P = 0.036). In contrast, adiponectin and the adiponectin/leptin ratio were not associated with alterations in HDL particles. Furthermore, HDL size was associated with resistin (β = -0.348, P = 0.007) and PAI-1 (β = -0.324, P = 0.004). HDL and AGE were related to insulin concentrations (β = 0.458, P = 0.015). Analyses were adjusted for age, sex, body mass index, triglycerides, and HDL-cholesterol.

Conclusion: HDL size was significantly associated with the ATIR/adiponectin ratio and inflammation, whereas glycation was more strongly related to the ATIR index. These findings have important implications for the management and prevention of cardiovascular disease in T2D patients.