Relationship between abnormal NOS expression and the pathogenesis of cerebral aneurysm

We sought to investigate the relationship between abnormal expression of nitric oxide synthase (NOS) and pathogenesis of cerebral aneurysm. Brain tissues were collected from 36 patients with cerebral aneurysm confirmed by computer tomography with angiography or neurosurgical therapy. The control group consisted of 25 patients of similar age who had no vascular diseases, as confirmed by magnetic resonance imaging. Samples of cortical arterioles were collected. The structure of the aneurysms was detected by hematoxylin and eosin staining, and the expression of inducible NOS was detected by immunohistochemistry. NOS expression was significantly higher in the patient group than in the control group (patients: 30/36 strongly positive; control: 0/25 strongly positive; P < 0.05). In conclusion, the pathogenesis underlying cerebral aneurysm may be due to abnormal expression of NOS, degradation of the extracellular matrix, aggravation of a pro-inflammatory reaction, or a deficiency in arterial elasticity layer synthesis. These changes may result in a deficiency in vascular remodeling.