ABSTRACT
Background: Cerebral saccular aneurysm is a major cause of subarachnoid hemorrhage, one of the cerebrovascular diseases with the highest mortality. The mechanisms underlying the development of aneurysm, however, still remain unclear. Objective: The authors have made a series of reports on an animal model of experimentally induced cerebral aneurysms that resemble human cerebral aneurysms in their location and morphology. The objective of this brief review is to introduce our evidence about the pathogenesis of cerebral aneurysms using the experimentally induced cerebral aneurysm model, particularly focused upon the role of nitric oxide (NO) and shear stress on degenerative changes of the arterial wall during aneurysm development. Methods: We first introduce methods of aneurysm-inducing surgery, and then refer to morphological analysis of aneurysmal induction. Next, we explain the association between aneurysmal development and shear stress and NO. Finally, we show several mechanisms of aneurysmal development using genetically modified animals. Results and conclusion: In our animal model, cerebral aneurysms are induced in rats, monkeys, and mice by ligation of the unilateral common carotid artery and renal hypertension, suggesting that an increase in hemodynamic stress is a key requirement for the aneurysm development. Our morphological and molecular studies suggest that increased wall shear stress, iNOS-derived NO, MMP-2 \& 9, cathepsin B, NF-κB, interleukin-1β, and endothelin B receptor are associated with the progression of cerebral aneurysms. Statin and Nifedipine may be possible drugs for the prevention of cerebral aneurysm development.
ABSTRACT
<p><b>BACKGROUND</b>In an earlier study, we identified a locus for Moyamoya disease (MMD) on 17q25.3.</p><p><b>METHODS</b>Linkage analysis and fine mapping were conducted for two new families in additional to the previously studied 15 families. Three genes, CARD14, Raptor, and AATK, were selected based on key words, namely, "inflammation", "apoptosis", "proliferation", and "vascular system", for further sequencing. A segregation analysis of 34 pedigrees was performed, followed by a case-control study in Japanese (90 cases vs. 384 controls), Korean (41 cases vs. 223 controls), Chinese (23 cases and 100 controls), and Caucasian (25 cases and 164 controls) populations.</p><p><b>RESULTS</b>Linkage analysis increased the LOD score from 8.07 to 9.67 on 17q25.3. Fine mapping narrowed the linkage signal to a 2.1-Mb region. Sequencing revealed that only one newly identified polymorphism, ss161110142, which was located at position -1480 from the transcription site of the Raptor gene, was common to all four unrelated sequenced familial affected individuals. ss161110142 was then shown to segregate in the 34 pedigrees studied, resulting in a two-point LOD score of 14.2 (P = 3.89 × 10(-8)). Its penetrance was estimated to be 74.0%. Among the Asian populations tested (Japanese, Korean, and Chinese), the rare allele was much more frequent in cases (26, 33, and 4%, respectively) than in controls (1, 1, and 0%, respectively) and was associated with an increased odds ratio of 52.2 (95% confidence interval 27.2-100.2) (P = 2.5 × 10(-49)). This allele was, however, not detected in the Caucasian samples. Its population attributable risk was estimated to be 49% in the Japanese population, 66% in the Korean population, and 9% in the Chinese population.</p><p><b>CONCLUSION</b>ss161110142 may confer susceptibility to MMD among East Asian populations.</p><p><b>ELECTRONIC SUPPLEMENTARY MATERIAL</b>The online version of this article (doi:10.1007/s12199-009-0116-7) contains supplementary material, which is available to authorized users.</p>