Objective To evaluate the feasibility of biodegradable flow-diverting stent for treatment of intracranial wide-neck aneurysm.Methods Twenty adult New Zealand rabbits were used to induce wide-neck aneurysm models by elastase,and then,these models were divided into 3 groups:in group one (n=7),biodegradable polyglycolic acid flow-diverting stents (PGA-FDs) were implanted into parent arteries and covered the necks of aneurysms;in group 2 (n=7),the bare metal FDs replaced PGA-FDs;the observation period of animals in group one and group 2 was 3 months;in group 3 (n=6),the PGA-FDs were implanted into parent arteries with 6 weeks of observation period.The status of aneurysm occlusion and patency of side branches covered by the stent were assessed,and all animals were sacrificed:HE staining was used to observe the thrombosis in the aneurysms,Elastic fiber staining was used to observe the neointimal thickness of parent arteries,and immuohistochemical staining was employed to detect the expressions of CD34,CD68 and alpha-actin (αSMA) in the parent arteries.Results Complete aneurysm occlusion rate in groups one,2 and 3 was 83.3％ (5/6),0％ (0/6) and 66.7％ (4/6),respectively.The neointimal thickness in parent artery of groups one,2 and 3 was (111±69) μm,(70±48) μm and (190±52) μm,respectively;that in group 3 was significantly higher than that in group one and 2 (P＜0.05).The neointima comprised predominantly smooth muscle cells and collagen fibers.Some CD34 positive vascular endothelial cells could be seen in the neointima of parent arteries of groups one and 2.Conclusion The PGA-FD is an effective device to occlude aneurysms without inducing obvious neointimal thickness and side branch stenosis in the 3-month follow-up.

Objective To evaluate the safety of biodegradable flow-diverting devices (FDs) for treatment of intracranial aneurysms in rabbits.Methods Biodegradable polyglycolic acid FDs (PGA-FDs) were implanted into the abdominal aorta in 12 New Zealand rabbits,covering the ostium of a lumbar artery.Animals underwent angiography at 3,6,and 12 weeks after device implantation;and 3 animals were sacrificed at 3 and 6 weeks for pathology by HE staining,Veigert resorcinol (VG) staining,and CD34,CD68 and α smooth muscle actin (αSMA) immunohistochemistry.The diameter of abdomen arota and the patency of side branches covered by the devices were assessed.All animals were sacrificed after angiography for pathology at 12 weeks.Results No side branch occlusions were noted,either immediately after implantation or at follow-ups.Abdominal aorta neointimal hyperplasia was minimal,and there were no differences immediately after device implantation,or at 3,6,and 12 weeks after device implantation (abdominal aorta diameter:[3.35±0.24] mm,[3.33 ±0.12] mm,[3.23±0.16] mm,[3.12±0.10] mm and [3.30±0.11] mm).Pathology results showed the neointima covered the strips of PGA-FD,and minial inflammation was abserved around the strips.The PGA strips were obsorbed completely at 12 weeks follow up with no apparent inflammation.The neointima predominantly comprised of smooth muscle cells and collagen fibers.Conclusion The PGA-FD is safe for abdominal aorta and normal side branches at short-term follow-up.

Objective To investigate the neuroprotective effects of protease-activated receptor (PAR)-1 antagonist SCH79797 on early stage of brain injury and expression patterns of brain-derived neuro trophic factor (BDNF) and nerve growth factor (NGF) after subarachnoid hemorrhage (SAH) in rats. Methods Fifty-four clean male SD rats were randomly divided into three groups:sham-operative group, SAH group and treatment group (n=18). SAH rat models in the later two groups were induced by single cisterna magna blood injection. Rats in the treatment group were given SCH79797 (25μg/kg) after SAH modeling. Neurologic function was assessed and scored after SAH for 24 h. Then the rats were sacrificed, and then, the brains were collected for determination of brain water content. The expression patterns of BDNF and NGF in cerebral tissues were tested by enzyme linked immunosorbent assay and immunofluorescence method. Results As compared with rats in the SAH group, rats in the treatment group had significantly increased neurological deficit scale scores (12.11 ±2.62 vs. 14.59 ±2.24), statistically decreased water content in brain tissues (83.01%±0.38%vs. 79.79%±0.44%), with significant difference (P<0.05). As compared with those in the SAH group, the expressions of BDNF and NGF in treatment group were significantly higher ([100.15±59.13] pg/mL vs. [368.00±137.52] pg/mL; [33.44± 2.21] pg/mL vs. [37.49±2.29] pg/mL, P<0.05). As compared with those in the SAH group, the immunofluorescent staining intensities of BDNF and NGF in treatment group were significantly higher (41.65±1.50 vs. 91.40±1.30;23.50±1.70 vs. 30.65±1.80, P<0.05). Conclusion SCH79797 given early may reduce the degree of brain edema and increase the expressions of BDNF and NGF, which has obvious neuroprotective effect.

Endosaccular flow diverter is a new endovascular device of treating intracranial wide neck bifurcation aneurysms. Four kinds of endosaccular flow diverters with different shapes and features have been produced and implanted into the intracranial aneurysms. This article provides a review on the features and clinical use of these new devices.