| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2004: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2003: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Elastin is a key extracellular matrix protein that is critical to the elasticity and resilience of many vertebrate tissues including large arteries, lung, ligament, tendon, skin, and elastic cartilage. Urinary tract needs tissue elasticity for efficient storage and passage of urine. We successfully developed a new tissue-engineered ureteral model with elastin matrix. However, this first-generation ureteral model lacked enough strength for surgical suture handling. To overcome this problem, we constructed scaffolds consisting of polylactic acid fibers and elastin for tissue engineering of the ureter. We evaluate the feasibility, safety and quality of tissue regeneration of this scaffold with a model of partial replacement of porcine ureter. Eight pigs underwent partial ureterectomy and the elastin/biodegradable polymer scaffolds were brought to close the defect. Four to sixteen weeks later, the kidneys and the ureters were resected and submitted to histological evaluation. Two of eight animals were dead postoperatively due to surgical complications. In 4 of 6 animals, the scaffolds showed significant shrinkage and stenosis, resulting in upper urinary tract dilatation. Although the scaffolds were degraded and absorbed after eight weeks, phagocytic giant cells were frequently observed even after 12 weeks, suggesting the elastin matrix acted as foreign body in this model. Degree and quality of tissue regeneration was different among the animals and there was no pattern. In general, urothelial regeneration was limited and smooth muscle layer was not observed. In summary, we successfully developed elastin/nano-fiber composite scaffold, there are still several problems to be solved in terms of tissue regeneration.
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