Haptoglobin genotype is associated with increased endothelial dysfunction serum markers in type 1 diabetes

To evaluate the genotype-driven effect of haptoglobin (Hp) in patients with type 1 diabetes without clinical cardiovascular (CV) disease, considering endothelial dysfunction (ED) and arterial stiffness (AS).

About 137 patients with type 1 diabetes (duration ≥ 5 years) and 68 age- and sex-matched controls were evaluated for the following: (i) smoking, alcohol intake, BMI, blood pressure, fasting plasma glucose, HbA1c and lipid profile; (ii) microvascular complications; (iii) serum markers of ED (ICAM-1, VCAM-1 and E-selectin); (iv) AS, assessed as aortic pulse wave velocity (aPWV); and (v) Hp genotype.

The prevalence of the 1/1, 2/1 and 2/2 Hp genotypes was 28.5%, 46.7% and 24.8% in patients with type 1 diabetes and 20.9%, 38.8% and 40.3% in controls, respectively. No differences were found in classical CV risk factors between patients homozygous for allele 2 and the remaining genotypes, both in patients with type 1 diabetes and controls. Patients with type 1 diabetes carrying the Hp2/2 genotype had higher concentrations of ICAM-1 (65.1 (56.7-76.0) ng/mL vs. 59.0 (51.7-69.3) ng/mL; P = 0.033) and sVCAM-1 (1133.1 (884.6-1458.6) ng/mL vs. 956.4 (738.5-1206.1) ng/mL; P = 0.040) than those without it. The Hp2/2 genotype remained independently associated with ED after adjusting for CV risk factors (P = 0.038). No significant differences were found for aPWV between Hp genotypes.

Endothelial dysfunction may be influenced by Hp2/2 genotype in patients with type 1 diabetes with independence of classical CV risk factors.