Relationship of YKL-40 and adiponectin and subclinical atherosclerosis in asymptomatic patients with type 1 diabetes mellitus from a European Mediterranean population

The glycoprotein YKL-40 is a new marker of early inflammation and endothelial dysfunction. Adiponectin is a collagen-like protein with anti-atherogenic and anti-inflammatory effects. Increased concentrations of both markers have been reported in patients with type 1 diabetes (T1D).

To assess the possible role of YKL-40 and adiponectin as a marker of subclinical cardiovascular disease in asymptomatic patients with type 1 diabetes with no history of ischemic or macrovascular heart disease and its relationship with other classic inflammatory biomarkers.

Concentrations of YKL-40, adiponectin, IL-6, IL-1β, TNF- α, hsCRP and homocysteine were determined in 150 T1D patients (58 % men, age: 38.6 ± 8.1 years, 20.4 ± 8.1 years of evolution, BMI: 25.1 ± 3.6 kg/m²; HbA_1c 8.1 ± 2.3 %, 48 % smokers; 26 % retinopathy, microalbuminuria 9 %) and 50 controls age, sex and smoke condition matched. Subclinical atherosclerosis was assessed by a carotid ultrasonography and a computed tomography for evaluation of calcium artery calcification score (CACS).

82 % of T1D patients and 92 % of controls had a calcium score of 0. T1D patients showed a significantly higher mean common carotid artery intima media thickness (CIMT) compared to controls (0.55 ± 0.14 vs 0.48 ± 0.14 mm, p = 0.01). Concentrations of YKL-40 and adiponectin were significantly higher in T1D [42.6 (10.4–195.0) vs ±28.7 (11.0–51.2) ng/ml, p = 0.001 and 15.8 ± 9.1 vs. 12.4 ± 5.3 mg/ml, p = 0.008], with no differences when compared to other inflammatory parameters. In T1D patients no association was found between YKL-40 and adiponectin and screening test for subclinical arterial disease (neither CACS nor CIMT). A positive correlation was found between levels of YKL-40 and age and duration of disease (r = 0.28, p = 0.003; r = 0.35, p = 0.001). There were no differences in the YKL-40 in relation to the presence or absence of retinopathy or nephropathy. Levels of adiponectin were higher in patients with nephropathy (21.84 ± 8.15 vs. 14.88 ± 8.27 mg/ml, p = 0.008).

Type 1 diabetes patients from a Mediterranean area with a longer disease evolution, although a lower degree of subclinical disease, showed significatively higher concentrations of YKL-40 and adiponectin compared with the controls. Therefore, we conclude that YKL-40 and adiponectin are early inflammatory markers in diabetic subjects even in the presence of a low atherosclerotic background.