Heme oxygenase-1 is expressed in carotid atherosclerotic plaques infected by Helicobacter pylori and is more prevalent in asymptomatic subjects

Background and Purpose - It is not well established what are the features, if any, that distinguish symptomatic from asymptomatic carotid atherosclerotic plaques. Inducible heme oxygenase-1 (HO-1) is a component of cellular defense mechanisms against oxidative stress. We aimed to assess the presence of Helicobacter pylori (H pylori) and the expression of HO-1 in carotid atherosclerotic plaques of patients with and without prior neurologic symptoms attributable to the operated artery. Methods - We examined 25 symptomatic and 23 asymptomatic carotid atherosclerotic plaques removed during endarterectomy and 7 normal carotid arteries obtained at autopsy. We investigated the presence of H pylori DNA in the vessel wall and performed immunohistochemical detection of HO-1. Results - H pylori DNA was present in 28 plaques and HO-1 was expressed in 30 plaques. HO-1 was found in 27 H pylori-positive specimens but in only 3 H pylori-negative specimens (P<0.001). All 7 normal carotid arteries were negative for both H pylori and HO-1. Although 82% of asymptomatic specimens were positive for H pylori and 87% for HO-1, only 36% of symptomatic specimens were positive for both H pylori and HO-1 (P<0.01). Conclusions - This study suggests a strong association between H pylori infection and expression of HO-1 in carotid atherosclerotic plaques. There was a substantial prevalence of these features in specimens obtained from asymptomatic subjects.