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

Background 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 ). Material and methods 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, HbA 1c 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. Results 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. Conclusions Endothelial dysfunction may be influenced by Hp2/2 genotype in patients with type 1 diabetes with independence of classical CV risk factors.