The photomicrograph shows loose, hypocellular, amorphous tissue in the dome

The photomicrograph shows loose, hypocellular, amorphous tissue in the dome. Section stained with H&E (magnification 60). densely infiltrated tissue, including chronic inflammatory tissue and RWJ-51204 extensive, attenuated collagen fiber bundles associated with myofibroblasts. Thick layers of myofibroblasts entirely bridged the necks. Absence of collagen deposition and scant myofibroblastic reaction to platinum coil embolization are seen in the rabbit model but not in swine aneurysms. The elastase-induced aneurysm model in rabbits is more suitable than sidewall swine aneurysms for testing of modified devices aimed at improving intra-aneurysmal fibrosis. Platinum coils have proved to be a valuable alternative to open surgical clipping for the treatment of RWJ-51204 intracranial aneurysms. However, limited histopathologic data in coil-embolized aneurysms in humans (1C6) and animal experiment studies (7C11) have suggested that platinum coils are biologically inert and fail to elicit a fibrotic response. These findings have prompted numerous investigators to explore coil modifications aimed at increasing the coils biologic activity (12C23). Advancing the efficacy of endovascular devices relies heavily on preclinical testing in animal models. An ideal animal model of human saccular aneurysms would mimic human histomorphologic and hemodynamic features, as well as simulate the human cellular and molecular milieu. Previously developed animal Rabbit polyclonal to Tyrosine Hydroxylase.Tyrosine hydroxylase (EC 1.14.16.2) is involved in the conversion of phenylalanine to dopamine.As the rate-limiting enzyme in the synthesis of catecholamines, tyrosine hydroxylase has a key role in the physiology of adrenergic neurons. models, including surgically created aneurysms in canines and swine, have been widely used for preclinical testing of endovascular devices in the past decade (7, 12, 16C19, 24C28). The use of surgically created, vein patch aneurysms, however, becomes questionable in the age of biologic modification, because the presence of disrupted arterial walls and suture lines yields unknown effects on the biology of the models. More recently, elastase-induced aneurysms in rabbits have been proposed as a useful preclinical tool for device development (9, 20C23, 29C32). Our previously published data (29, 30) have shown these model aneurysms are similar to that of human aneurysms in size and shape, and, left untreated, aneurysms remain patent reliably for as long as 2 years (Y. H. Ding et al, unpublished data, 2005). Furthermore, because these experimental aneurysms occur at a prominent curve along the brachiocephalic artery and are close to the aorotic root, the aneurysm neck is subject to high shear stress (33C35), similar to that noted in ophthalmic aneurysms in humans (30). In addition, the wall of this model simulates human aneurysms with the internal elastic lamina markedly diminished or absent (29, 36). Finally, model creation is done without the need for sutures along the aneurysm neck. Relatively little is known about the histopathologic differences and cellular and biologic reactions to coil embolization among species, including human aneurysms. In addition, there currently exists no reliable technique for detailed histopathologic study of aneurysms treated with endovascular coils. The presence of metal precludes standard processing methods. Thus, few previous reports have applied any advanced histologic techniques such as for example immunohistochemistry or immunofluorescence to explore the mobile and biologic response induced by coil embolization. As a total result, the biologic response for an implanted gadget is normally clouded as well as the knowledge of the curing response to coils continues to be poor. In today’s study, a improved paraffin-embedding way of processing coil-bearing tissues was utilized to RWJ-51204 review the long-term histopathologic and immunohistochemical results in rabbit and swine aneurysms. These results were weighed against those within a individual aneurysm, so that they can further clarify.