Multiplicative impact of smoking and genetic predisposition on intracranial aneurysm formation

The impact of smoking on neurosurgical outcomes

Cigarette smoking is a common health risk behavior among the general adult population, and is the leading preventable cause of morbidity and mortality in the US. The surgical literature shows that active tobacco smoking is a major risk factor for perioperative morbidity and complications, and that preoperative smoking cessation is an effective measure to lower these risks associated with active smoking. However, few studies have examined the effects of smoking and perioperative complications following neurosurgical procedures. The goal of this review was to highlight the scientific data that do exist regarding the impact of smoking on neurosurgical outcomes, to promote awareness of the need for further work in the specific neurosurgical context, and to suggest ways that neurosurgeons can promote smoking cessation in their patients and lead efforts nationally to emphasize the importance of preoperative smoking cessation. This review indicates that there is limited but good evidence that smoking is associated with higher rates of perioperative complications following neurosurgical intervention. Specific research is needed to understand the effects of smoking and perioperative complications. Neurosurgeons should encourage preoperative smoking cessation as part of their clinical practice to mitigate perioperative morbidity associated with active smoking.

The expression of SPARC in human intracranial aneurysms and its relationship with MMP-2/-9

Objective

SPARC is a key determinant of invasion and metastasis in some tumors, such as gliomas, melanomas and prostate tumors. SPARC can change the composition and structure of the matrix and promote angiogenesis; these effects are closely related to clinical stage and the prognosis of tumors such as meningiomas. However, little is known about the expression of SPARC in intracranial aneurysms. The goal of this study was to establish the role of SPARC in human intracranial aneurysms.

Methods

Thirty-one intracranial aneurysms were immunohistochemically stained for SPARC, MMP-2 and MMP-9. As controls, normal Circle of Willis arteries were similarly immunostained. All specimens were retrieved during autopsies and were embedded in paraffin. To evaluate the expression levels of SPARC, MMP-2 and MMP-9, western blotting was also performed in three available intracranial aneurysm specimens. The limited availability of fresh intracranial aneurysm tissue was the result of the majority of patients choosing endovascular embolization.

Results

The results showed that SPARC, MMP-2 and MMP-9 were strongly expressed in intracranial aneurysm tissues; however, these proteins were expressed minimally or not at all in normal Circle of Willis arteries. The western blot results showed that the expression levels of SPARC, MMP-2 and MMP-9 were significantly up-regulated in intracranial aneurysms relative to the expression levels in the normal Circle of Willis arteries. Data analysis showed that SPARC was significantly correlated with MMP-2 and MMP-9, also with age and risk factors but not with the Hunt-Hess grade or with sex.

Conclusion

The results indicate that SPARC is widely expressed in human intracranial aneurysms, and its expression correlates with MMP-2 and MMP-9 expression, age and risk factors but not with the Hunt-Hess grade. The results of this study suggest that SPARC has a pathogenic role in the alteration of the extracellular matrix of intracranial arteries during aneurysm formation.