No abstract available.
Hyperplasia* ; Neointima* ; Thalidomide*

No abstract available.
Hyperplasia* ; Neointima* ; Thalidomide*

The purpose of this study was to investigate the patency rates and the histologic findings of neoendothelialization according to the length of implanted polytetrafluoroethylene (PTFE) with an internal diameter of 3mm. Under the operating microscope, grafts of 8 and 24mm in length were implanted in the right carotid arteries of thirty rabbits by interrupted end-to-end microanastomosis. They were divided into two groups according to the length of implanted PTFE. Each group had fifteen rabbits. All implanted grafts were 25micro meter in fibril length and 0.39mm in wall thickness. Three grafts per group were harvested at 1, 2, 4, 8, and 12 weeks after implantation and all grafts were observed for patency rates and the histologic findings with a light microscope and scanning electron microscope. In conclusion, there was no difference in patency rates according to the length of implanted PTFE. However, the formation of neointima and subintimal tissue was delayed and incomplete in the longer implanted PTFE group.
Carotid Arteries ; Neointima ; Polytetrafluoroethylene* ; Rabbits ; Transplants

The purpose of this study was to investigate the patency rates and the histologic findings of neoen- dothelialization according to the length of implanted polytetrafluoroethylene (PTFE) with an internal diameter of 3 mm. Under the operating microscope, grafts of 8 and 24 mm in length were implanted in the right carotid arteries of thirty rabbits by interrupted end-to-end microanastomosis. They were divided into two groups according to the length of implanted PTFE. Each group compised fifteen rabbits. All implanted grafts were 25 pm in fibril length and 0.39 mm in wall thickness. Three grafts per group were harvested at 1, 2, 4, 8, and 12 weeks after implantation respectively and all grafts were observed for patency rates and the histologic findings with light microscope and scanning electron microscope. In conclusion, there was no difference in patency rates according to the length of implanted PTFE and histologically the formation of neointima and subintimal tissue was delayed and incomplete in longer implanted PTFE.
Carotid Arteries ; Neointima ; Polytetrafluoroethylene* ; Rabbits ; Transplants

Neointimal hyperplasia is the main mechanism of stent restenosis. Therefore, drug-eluting stents have replaced bare metal stents because there is less neointima and scar formation. Recently, some cases of stent restenosis after using a bare metal stent were found to involve calcification, not neointimal hyperplasia, and regarded as de novo atherosclerosis. We report unusual circular calcification inside a drug-eluting stent, which we called neointimal calcification.
Atherosclerosis ; Cicatrix ; Drug-Eluting Stents ; Hyperplasia ; Neointima ; Stents

Neointimal hyperplasia is the main mechanism of stent restenosis. Therefore, drug-eluting stents have replaced bare metal stents because there is less neointima and scar formation. Recently, some cases of stent restenosis after using a bare metal stent were found to involve calcification, not neointimal hyperplasia, and regarded as de novo atherosclerosis. We report unusual circular calcification inside a drug-eluting stent, which we called neointimal calcification.
Atherosclerosis ; Cicatrix ; Drug-Eluting Stents ; Hyperplasia ; Neointima ; Stents

BACKGROUND: Restenosis remains one of major clinical problems in the coronary intervention. The effects of local radiation using radioactive balloon loaded with Ho-166 on coronary restenosis in the porcine model were observed. METHODS: Overdilation injury was performed in porcine coronary arteries using control balloon [Group I, n=, left anterior descending artery (LAD)=, left circumflex artery (LCX)=, right coronary artery (RCA)=] and Ho-166 loaded polyurethane-coating balloon [Group II; n=0, 21.98.1 mCi (20 Gy at 0.5 mm in depth), LAD=, LCX=, RCA=] at 5 atm for 3 min. Follow-up quantitative coronary angiogram (QCA) and histopathologic findings were compared at 4 weeks after balloon injury between two groups. RESULTS: Acute or late thrombotic arterial occlusion was not observed in both groups. Diameter stenosis measured by QCA was not different between two groups (Group I: 11.61.6%, II: 7.68.4%, P=.44). On histopathologic study, injury score, external and internal elastic lamina area, and media area were not different between two groups. Neointimal area and histopathologic area stenosis were significantly higher in Group I (0.320.86mm2, 20.677.01%) than those of Group II (0.150.26mm2, 12.032.44%). By immunocytochemistry, proliferating cell nuclear antigen indices in neointima and media were 8.244.44%, 7.972.46% in Group I, and 7.172.25%, 5.471.44% in Group II, which were not different between two groups(P=.587, 0.089). CONCLUSION: Local radiation using Ho-166 balloon is effective in reducing neointimal proliferation in a porcine model.
Arteries ; Constriction, Pathologic ; Coronary Restenosis* ; Coronary Vessels ; Follow-Up Studies ; Immunohistochemistry ; Neointima ; Proliferating Cell Nuclear Antigen

PURPOSE: To evaluate changes of residual aneurysms according to the size of aneurysmal neck andthrombogenicity of a tungsten coil after incomplete embolization of experimental lateral aneurysms. MATERIALS AND METHODS: Eleven experimental lateral aneurysms with different aneurysmal neck size were created in the commoncarotid arteries of mongrel dogs. They were then divided into narrow-neck(n=3), wide-neck(n=6) and spontaneouslythrombosed control(n=2) groups. After confirmation of aneurysmal patency, incomplete embolizations of varyingdegrees (about 30% to near total occlusion) were performed using 5mm-diameter tungsten coils. Angiography wasperformed immediately before and after, and one and six weeks after embolizations. The size of residual aneurysmwas measured on each angiogram. After the last angiography, embolized aneurysms were excised and examined underlight and electron microscopes. RESULTS: On angiograms obtained 6 weeks after embolization, all residual narrowneck aneurysms were completely occluded, whereas in those with a wide-neck, therre was either no change (n=4) or aslight increase in size(n=2). On light microscopy, all narrow-neck aneurysms showed total organized fibrosis whileall control aneurysms and half those with a wide neck showed unorganized thrombi. The embolized group showed ahigher degree of organization in the aneurysmal cavity than did the control group. Neointima formation was seen inall embolized aneurysms, but no aneurysm showed foreign body reaction. On electron microscopy, uniform thicknessof plasma coatings was noted on the surface of the tungsten coils. CONCLUSION: A wide-neck residual aneurysm maypersist or increase in size, while one with a narrow-neck can be thrombosed after incomplete embolization withtungsten coils in a lateral aneurym. Careful consideration might be necessary in the embolization of wide-neckaneurysms. With plasma coatings on its surface and organized fibrosis, tungsten coil can be an useful forembolization of an aneurysm.
Aneurysm* ; Angiography ; Animals ; Arteries ; Dogs* ; Fibrosis ; Foreign-Body Reaction ; Microscopy ; Microscopy, Electron ; Neck ; Neointima ; Plasma ; Tungsten*

BACKGROUNDDrug-eluting stents represent a major advance in interventional cardiology. However, the current drug-eluting stents have significant limitations. One of the major problems is very late stent thrombosis, which is likely caused by inflammation and a hypersensitivity reaction related to a polymer on the stent. A polymer-free sirolimus-eluting stent with a unique nano-porous surface has been developed. This study aimed to evaluate this novel polymer-free sirolimus-eluting stent for its efficacy and safety in a pig model.

METHODSStents were directly coated with sirolimus (a drug concentration of 2.2 µg/mm(2) on the stent surface). The polymer-free sirolimus-eluting stents (PFSES) were compared to standard polymer-coated sirolimus-eluting stents (PCSES) and bare-metal stents (BMS) in 18 pigs.

RESULTSAt one month the degree of neointimal hyperplasia was similar between the two sirolimus-eluting stent groups and was significantly less compared to BMS ((1.93 ± 0.51) mm(2), (1.57 ± 0.69) mm(2) vs. (4.45 ± 1.05) mm(2), P < 0.05) At three months, PFSES maintained the low level of neointima ((2.41 ± 0.99) mm(2) vs. (4.32 ± 1.16) mm(2), P < 0.05), whereas PCSES had developed significant neointimal proliferation similar to BMS. The inflammation level was significantly higher in PCSES when compared with BMS three months post-implantation (2.50 ± 0.55 vs. 0.83 ± 0.75, P < 0.05) whereas PFSES showed a low level of inflammation comparable to PCSES (1.33 ± 0.52 vs. 2.50 ± 0.55, P < 0.05).

CONCLUSIONThe PFSES is effective and safe, and appears to be superior to standard PCSEs.

Animals ; Drug-Eluting Stents ; adverse effects ; Neointima ; prevention & control ; Polymers ; chemistry ; Sirolimus ; therapeutic use ; Swine

Intimal accumulation of smooth muscle cells contributes to the development and progression of atherosclerotic lesions and restenosis following endovascular procedures. Arterial smooth muscle cells display heterogeneous phenotypes in both physiological and pathological conditions. In response to injury, dedifferentiated or synthetic smooth muscle cells proliferate and migrate from the tunica media into the intima. As a consequence, smooth muscle cells in vascular lesions show a prevalent dedifferentiated phenotype compared to the contractile appearance of normal media smooth muscle cells. The discovery of abundant stem antigen-expressing cells in vascular lesions also rarely detected in the tunica media of normal adult vessels stimulated a great scientific debate concerning the possibility that proliferating vascular wall-resident stem cells accumulate into the neointima and contribute to the progression of lesions. Although several experimental studies support this hypothesis, others researchers suggest a positive effect of stem cells on plaque stabilization. So, the real contribute of vascular wall-resident stem cells to pathological vascular remodelling needs further investigation. This review will examine the evidence and the contribution of vascular wall-resident stem cells to arterial pathobiology, in order to address future investigations as potential therapeutic target to prevent the progression of vascular diseases.
Adult ; Endovascular Procedures ; Humans ; Myocytes, Smooth Muscle ; Neointima ; Pathology* ; Phenotype ; Stem Cells* ; Tunica Media ; Vascular Diseases