Haptoglobin polymorphism and lacunar stroke

Haptoglobin (Hp) 2-2 phenotype has been associated with peripheral and coronary artery disease and risk of vascular complications in diabetic patients, but any association of Hp polymorphism with cerebrovascular disease has not been explored so far. We aimed to study Hp polymorphism in a sample of 124 patients with a rather homogeneous type of cerebrovascular disease, namely first symptomatic lacunar stroke due to small vessel disease, in comparison with a large (n=918) control group. Hp phenotypes were determined using starch gel electrophoresis. Hp1 allele frequency was significantly higher in patients than in controls (0.480 vs. 0.395, p < 0.05), mainly due to a lower Hp2-2 phenotype frequency (25.0 vs. 36.3 %; OR 0.59; 95% CI 0.38-0.90; p < 0.05). This was even more pronounced in younger (60 years) patients (Hp1 allele frequency 0.539). Concomitant asymptomatic lacunar lesions were present in 82 patients, extensive white matter lesions in 47 patients. The association between Hp1 and lacunar stroke suggests that Hp may serve different functions depending on the pathological processes in various types of vascular disease in different organs. The association between Hp1 and lacunar stroke may relate to blood-brain barrier dysfunction, to the association between hypertension and cerebral small vessel disease, or a special dependence of small vessel wall integrity on Hp2-2 related angiogenic potential. The presence of concomitant signs of cerebral small vessel disease weakened the association between Hp1 and lacunar stroke, which could reflect a difference in underlying vascular pathophysiology in which Hp phenotype may play a different role.