Healing Mechanisms of High-Porosity PTFE Grafts: Significance of Transmural Structure

Tsuchida, Hideaki; Wilson, Samuel E.; Ishimaru, Shin

doi:10.1006/jsre.1997.5158

Cited by 13 publications

(11 citation statements)

References 13 publications

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“…To seed BMCs in ePTFE vascular prostheses stably, high porosity (60 to 90 m and more; fibril length) is thought to be advantageous for endothelialization in vivo, because the anchoring of seeded cells and the capillary ingrowth from perigraft tissue are likely to occur. [11][12][13] Hence, in this study, we chose highporosity ePTFE (90 m; fibril length) as a scaffold and were able to succeed in expressing recombinant proteins. This result may be consistent with the work of Noishiki et al 4 demonstrating that BMC-seeded high-porosity vascular prosthesis exhibited autocrine function of angiogenic factor.…”

Section: Discussionmentioning

confidence: 99%

Synthetic Vascular Prosthesis Impregnated With Mesenchymal Stem Cells Overexpressing Endothelial Nitric Oxide Synthase

et al. 2006

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Background-Endothelial dysfunction is known to exaggerate coronary artery disease, sometimes leading to irreversible myocardial damage. In such cases, repetitive coronary revascularization including coronary artery bypass grafting is needed, which may cause a shortage of graft conduits. On the other hand, endothelial nitric oxide synthase (eNOS) is an attractive target of cardiovascular gene therapy. The vascular prostheses, of which the inner surfaces are covered with mesenchymal stem cells (MSCs) overexpressing eNOS, are expected to offer feasible effects of NO and angiogenic effects of MSCs on the native coronary arterial beds, as well as improvement of self-patency. Herein, we attempted to develop small caliber vascular prostheses generating the bioactive proteins. Also, we attempted to transduce eNOS cDNA into MSCs. Methods and Results-The MSCs were isolated from rat bone marrow and transduced with each adenovirus harboring rat eNOS cDNA and ␤-galactosidase (␤-gal) (eNOS/MSCs and ␤-gal/MSCs). The ␤-gal/MSCs were impregnated into vascular prostheses, then the expressions of ␤-gal on the inner surfaces of them were evaluated by 5-bromo-4-chloro-3-indolyl ␤-D-galactoside staining. The NOS activity of eNOS/MSCs was assayed by monitoring the conversion of 3 H-arginine to 3 H-citrulline. The inner surfaces of the vascular prostheses were covered with MSCs expressing ␤-gal. The amount of the 3 H-citrulline increased, and eNOS/MSCs were determined to generate enzymatic activity of eNOS. This activity was completely inhibited by N G -nitro-L-arginine methyl ester. Key Words: mesenchymal stem cells Ⅲ endothelial nitric oxide synthase Ⅲ gene-transduction Ⅲ adenovirus Ⅲ small caliber expanded polytetrafluoroethylene (ePTFE) vascular prosthesis I mpaired endothelial function induces several cardiovascular diseases, including atherosclerosis, hypertension, heart failure, arteriosclerosis obliterans, and coronary heart disease. Endothelial dysfunction also causes NO insufficiency, resulting in the limitation of NO-mediated signal transduction and excretion of bioactive hormone-like products. 1 The attenuated production of NO and the hormone-like products exaggerates these cardiovascular diseases further. Coronary artery disease is one of the most critical diseases enhanced by endothelial dysfunction, sometimes leading to irreversible myocardial damage. Some patients require repetitive coronary revascularization, including coronary artery bypass grafting, which may lead to a shortage of graft materials. Conclusions-TheSmall caliber vascular prostheses, which would be suitable for graft conduits for coronary artery bypass grafting or arteriosclerosis obliterans below the knee, have an extremely high failure rate that is attributed to thrombus formation and occlusion. Many attempts have been made to increase the patency of small-caliber vascular prostheses over the years. Recently, vascular grafts releasing NO infer possibilities preventing thrombosis and stenosis. 2,3 However, they are far from practical use, because the ma...

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Section: Discussionmentioning

confidence: 99%

Synthetic Vascular Prosthesis Impregnated With Mesenchymal Stem Cells Overexpressing Endothelial Nitric Oxide Synthase

et al. 2006

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“…Therefore, the incorporation of designed porosity into a synthetic scaffold is essential for rapid tissue regeneration, both in artificial and hybrid organs. For example, the fate of implanted artificial grafts has been discussed over the years in terms of porosity [1][2][3][4][5][6][7][8][9][10][11][12][13] : Greater porosity enhances tissue regeneration via transmural cell migration and proliferation and subsequent production of extracellular matrix. [10][11][12][13][14][15] These morphogenetic events eventually lead to a higher patency rate.…”

Section: Introductionmentioning

confidence: 99%

Surface microarchitectural design in biomedical applications:In vivo analysis of tissue ingrowth in excimer laser-directed micropored scaffold for cardiovascular tissue engineering

Nakayama

Nishi

Ishibashi‐Ueda

et al. 2000

J. Biomed. Mater. Res.

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A micropatterned microporous segmented polyurethane film (20 x 12 mm in size, 30 micrometer thick) with four regions was prepared by excimer laser microprocessing to provide an in vivo model of transmural tissue ingrowth in an open cell-structured scaffold specially designed for cardiovascular tissue engineering. Three microporous regions had the same circular micropores (30 micrometer diameter) but different pore density arrangements (percentage of total pore area against unit area was 0.3%, 1.1%, and 4.5%), and the other region remained nonporous. The covered stent, prepared by wrapping the regionally different density-microporous film on an expandable metallic stent (approximately 3.1 mm in diameter), was delivered to the luminal surface of canine common carotid arteries and placed after expansion of the stent to a diameter of approximately 8 mm using a balloon catheter. At 4 weeks of implantation, all the covered stents (n = 10) were patent. The luminal surfaces of the covered stents were almost confluently endothelialized both in nonporous and microporous regions. Histological examination showed that the neointimal wall was formed by tissue ingrowth from host through micropores (transmural) and anastomotic sites. Thrombus formation occurred frequently in the lowest density porous region and nonporous region. With an increase in pore density, the thickness of the neointimal wall decreased. This study demonstrated how the micropore density of implanted devices influences tissue ingrowth in arterial implantation.

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“…Sixty vascular implants in Sprague-Dawley rats and twenty tissue replacements in New Zealand rabbits reacted similarly with respect to cellular and vascular colonization, collagenization, foreign body reaction and final encapsulation. The healing mechanisms of implanted prostheses were also described by Tsuchida et al (1997), who implanted four types of PTFE grafts in both carotid and femoral arteries of dogs. The grafts were different with respect to porosity and were not preclotted or coated prior to implantation.…”

Section: Healingmentioning

confidence: 95%

“…It was concluded that the primary mechanism for endothelialization is ingrowth from the anastomoses (edges) of the graft, rather than transmural tissue migration or deposition of a multipotential cell from the blood. Transmural fibrocapillary incorporation did, however, support endothelial attachment and in-growth from the anastomoses (Tsuchida et al, 1997).…”

Section: Healingmentioning

confidence: 98%

Endothelialization of Small-Diameter Vascular Prostheses

Zijpp¹,

A.A.²,

Feijen³

2003

Archives of Physiology and Biochemistry

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In the field of arterial vascular reconstructions there is an increasing need for functional small-diameter artificial grafts (inner diameter < 6 mm). When autologous replacement vessels are not available, for example because of the bad condition of the vascular system in the patient, the surgeon has no other alternative than to implant a synthetic polymerbased vessel. After implantation the initial major problem concerning these vessels is the almost immediate occlusion, due to blood coagulation and platelet deposition, under the relatively low flow conditions. As the search for the perfect bio-inert polymer has not revealed a material with suitable properties for this application, improved performance of small-diameter artificial blood vessels is now being sought in the biological field. The poor blood-compatibility of an artificial vascular graft is not simply because of its coagulation-stimulating or platelet-activating properties, but more due to its inability to actively participate in the prevention of blood coagulation and platelet deposition. As these functions are naturally performed by endothelial cells, the utilization of these cells seems inevitable for the construction of a functional small-diameter artificial blood vessels. This review describes the current status of the use of endothelial cells to improve the performance of artificial vascular prostheses.

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Healing Mechanisms of High-Porosity PTFE Grafts: Significance of Transmural Structure

Cited by 13 publications

References 13 publications

Synthetic Vascular Prosthesis Impregnated With Mesenchymal Stem Cells Overexpressing Endothelial Nitric Oxide Synthase

Synthetic Vascular Prosthesis Impregnated With Mesenchymal Stem Cells Overexpressing Endothelial Nitric Oxide Synthase

Surface microarchitectural design in biomedical applications:In vivo analysis of tissue ingrowth in excimer laser-directed micropored scaffold for cardiovascular tissue engineering

Endothelialization of Small-Diameter Vascular Prostheses

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