The Impact of Type 2 Diabetes on Circulating Adipokines in Patients with Metabolic Syndrome

AIM: The aim of the study was to investigate, whether type 2 diabetes independently influences adipokines and inflammatory markers in patients with metabolic syndrome. METHODS: 36 patients with metabolic syndrome without type 2 diabetes and 39 patients with metabolic syndrome with type 2 diabetes, carefully matched for age, sex, and BMI, were investigated. Primary outcome measures were circulating adipokines and inflammatory markers (adiponectin, leptin, visfatin, vaspin, resistin, TNF-α, IL-6, monocyte chemoattractant protein-1 (MCP-1), retinol binding protein 4 (RBP-4), growth differentiation factor-15 (GDF-15)). In addition, we determined parameters of glucose and lipid metabolism. RESULTS: Patients with metabolic syndrome and type 2 diabetes had significantly lower levels of plasma total cholesterol, low-density lipoprotein cholesterol and triglycerides (p < 0.05). They displayed higher GDF-15 concentrations (1,113 ± 135 vs. 656 ± 63 pg/ml, p = 0.005) and lower visfatin concentrations (3.7 ± 0.3 vs. 4.8 ± 0.2 ng/ml, p = 0.009). There were no differences in other adipokines and inflammatory markers between both groups. CONCLUSIONS: In patients with metabolic syndrome, type 2 diabetes leads to decreased visfatin and increased GDF-15 serum levels when compared to carefully matched non-diabetic subjects. Whether the increase in GDF-15 is an indicator or a causal factor for the increased cardiovascular risk in diabetic subjects remains to be investigated in further studies.