Implantation of Renal Segments on Biodegradable Polymer Scaffolds / 대한이식학회지

PURPOSE: Dialysis and renal transplantation, the current therapies for end-stage renal disease (ESRD), have limitations including severe complications, donor organ shortage, and allograft failure. The present study investigated the possibility of using a tissue engineering technique for renal reconstruction as a new method to replace the current suboptimal treatments for ESRD. We reconstituted renal units in vivo by transplanting isolated renal segments on three-dimensional, biodegradable polymer scaffolds. METHODS: Renal segments were freshly isolated from Sprague-Dawley rat kidneys and seeded onto porous mesh matrices fabricated from polyglycolic acid, a biodegradable synthetic polymer. The renal segment-seeded scaffolds were implanted into subcutaneous spaces of athymic mice for two and four weeks. Retrieved specimens were examined by histological analyses. RESULTS: The tubular structures with hollow centers and vascular tufts of glomerulus-like structures were identified by histological analyses of the 2 and 4 week specimens. In contrast, no renal-like structures were observed from unseeded polymer implants (negative controls). CONCLUSION: These results suggest a possibility of reconstituting the renal structures by transplanting renal segments on polymer scaffolds and could be applid for partial or full replacement of kidney function in the treatment of ESRD.

Development of a Tissue-Engineered Vascular Graft Using Autologous Bone Marrow-Derived Cells and Biodegradable Polymer Scaffold

PURPOSE: The objective of this study is to develop a tissue-engineered vascular graft using autologous bone marrow-derived cells (BMCs) and biodegradable polymer scaffold. METHOD: Autologous canine BMCs were isolated from bone marrow aspirate and cultured. A tubular scaffold was fabricated by immersing polyglycolic acid (PGA) sheet in poly (glycolide-co-caprolactone) (PGCL) solution and wrapping it around a cylindrical mold. The expanded BMCs were seeded onto the PGA/PGCL tubular scaffold (internal diameter: 7 mm, length: 35 mm) and further cultured in vitro for 1 week. The graft was anastomosed to the abdominal artery in a canine model. One week after implantation, the retrieved graft was investigated by histological and immunohistochemical analyses. RESULT: Cultured BMCs differentiated into endothelial-like and smooth muscle-like cells. The PGA tubular scaffold reinforced with PGCL was successfully implanted in an animal model without graft rupture. The vascular graft engineered with BMCs was occluded at 1 week after implantation due to thrombus formation. Histological and immunohistochemical analyses of the retrieved graft revealed that extracellular matrix proteins such as smooth muscle alpha-actin, smooth muscle myosin heavy chain and collagen were produced partially in the graft media. CoNCLUSION: The tissue-engineered vascular graft developed in this study led to graft failure due to early occlusion. Nevertheless, it is confirmed that the PGA/PGCL scaffold has microstructures appropriate for cell proliferation and good mechanical properties. This result suggests the possibile application of this scaffold as a material for engineering of diseased vascular tissues.