OBJECT: The increased incidence of cerebral aneurysms in postmenopausal women appears to be related to low levels of circulating estrogen. Using a rat model of aneurysm induction, the authors found that oophorectomy increased the incidence of experimental cerebral aneurysms (Part I in this issue). In the current study they examined the effects of hormone replacement therapy (HRT) on the formation of cerebral aneurysms in rats. METHODS: Forty-five female Sprague-Dawley rats were divided into three equal groups. The animals in Groups A and B were subjected to a cerebral aneurysm induction procedure (renal hypertension and right common carotid artery ligation) followed 1 month later by bilateral oophorectomy. After an additional week the rats in Group A received 17beta estradiol continuous-release pellets. The rats in Group C served as controls. Three months after the aneurysm induction procedure, all the rats were killed and vascular corrosion casts of their cerebral arteries were prepared and checked for aneurysmal changes. Using a scanning electron microscope, the authors recorded aneurysmal changes as endothelial changes alone (Stage I), endothelial changes with intimal pad elevation (Stage II), and saccular aneurysm formation (Stage III). Aneurysmal changes (Stages I, II, and III) occurred in one third of rats that had undergone oophorectomy and were receiving HRT (Group A), compared with 87% of the rats that had undergone oophorectomy but did not receive HRT (Group B). Although most of the aneurysmal changes identified in Group A rats were limited to Stage I or II, most changes in Group B animals were identified as saccular dilation (Stage III). CONCLUSIONS: The findings demonstrated the significant protective role of estrogen against the formation and progression of cerebral aneurysms. It appears to be related to the beneficial effects of estrogen on the function and growth of endothelial cells, which play a major role in preserving the integrity of the vascular wall.
OBJECT: The increased incidence of cerebral aneurysms in postmenopausal women appears to be related to low levels of circulating estrogen. Using a rat model of aneurysm induction, the authors found that oophorectomy increased the incidence of experimental cerebral aneurysms (Part I in this issue). In the current study they examined the effects of hormone replacement therapy (HRT) on the formation of cerebral aneurysms in rats. METHODS: Forty-five female Sprague-Dawley rats were divided into three equal groups. The animals in Groups A and B were subjected to a cerebral aneurysm induction procedure (renal hypertension and right common carotid artery ligation) followed 1 month later by bilateral oophorectomy. After an additional week the rats in Group A received 17beta estradiol continuous-release pellets. The rats in Group C served as controls. Three months after the aneurysm induction procedure, all the rats were killed and vascular corrosion casts of their cerebral arteries were prepared and checked for aneurysmal changes. Using a scanning electron microscope, the authors recorded aneurysmal changes as endothelial changes alone (Stage I), endothelial changes with intimal pad elevation (Stage II), and saccular aneurysm formation (Stage III). Aneurysmal changes (Stages I, II, and III) occurred in one third of rats that had undergone oophorectomy and were receiving HRT (Group A), compared with 87% of the rats that had undergone oophorectomy but did not receive HRT (Group B). Although most of the aneurysmal changes identified in Group A rats were limited to Stage I or II, most changes in Group B animals were identified as saccular dilation (Stage III). CONCLUSIONS: The findings demonstrated the significant protective role of estrogen against the formation and progression of cerebral aneurysms. It appears to be related to the beneficial effects of estrogen on the function and growth of endothelial cells, which play a major role in preserving the integrity of the vascular wall.
Authors: Nohra Chalouhi; Muhammad S Ali; Pascal M Jabbour; Stavropoula I Tjoumakaris; L Fernando Gonzalez; Robert H Rosenwasser; Walter J Koch; Aaron S Dumont Journal: J Cereb Blood Flow Metab Date: 2012-07-11 Impact factor: 6.200
Authors: Daisuke Wajima; Siham Hourani; William Dodd; Devan Patel; Chad Jones; Kartik Motwani; Hanain Z Fazal; Koji Hosaka; Brian L Hoh Journal: Neurosurgery Date: 2020-04-01 Impact factor: 4.654
Authors: Felicitas J Detmer; Bong Jae Chung; Carlos Jimenez; Farid Hamzei-Sichani; David Kallmes; Christopher Putman; Juan R Cebral Journal: Neuroradiology Date: 2018-11-19 Impact factor: 2.804
Authors: Nefize Turan; Robert Allen-James Heider; Dobromira Zaharieva; Faiz U Ahmad; Daniel L Barrow; Gustavo Pradilla Journal: Transl Stroke Res Date: 2015-11-16 Impact factor: 6.829
Authors: Yoshiteru Tada; Hiroshi Makino; Hajime Furukawa; Kenji Shimada; Kosuke Wada; Elena I Liang; Shoko Murakami; Mari Kudo; David K Kung; David M Hasan; Keiko T Kitazato; Shinji Nagahiro; Michael T Lawton; Tomoki Hashimoto Journal: Neurosurgery Date: 2014-12 Impact factor: 4.654