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Tissue engineering of autologous aorta using a new biodegradable polymer
D Shum-Tim1, U Stock, J Hrkach
1Department of Cardiovascular Surgery, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
The Annals of Thoracic Surgery
|January 5, 2000
Summary
Tissue-engineered vascular grafts using a polyhydroxyalkanoate-polyglycolic acid copolymer in sheep demonstrated patency and native-like aortic characteristics. This novel approach avoids aneurysm formation, paving the way for "live" vascular grafts.
Area of Science:
- Biomaterials Science
- Regenerative Medicine
- Vascular Surgery
Background:
- Previous tissue-engineered (TE) vascular grafts using polyglycolic acid (PGA)-polyglactin copolymers led to aneurysms in systemic circulation.
- This study investigates a novel TE vascular graft using a polyglycolic acid (PGA)-polyhydroxyalkanoate (PHA) copolymer.
Purpose of the Study:
- To evaluate the efficacy and safety of a TE vascular graft composed of a PGA-PHA copolymer in the systemic circulation.
- To assess the development of aneurysms and graft patency in a lamb model.
Main Methods:
- Ovine carotid arteries were used to create autologous cell-seeded tubular scaffolds (7-mm diameter) from PHA-PGA copolymer.
- These TE vascular constructs replaced abdominal aortic segments in lambs (n=7), with acellular polymer tubes used as controls (n=4).
- Graft patency, histological analysis, DNA and collagen content, mechanical properties, and matrix metalloproteinase (MMP) activity were evaluated.
Main Results:
- All TE grafts remained patent throughout the study period, with no aneurysm formation observed.
- Control grafts occluded within days to weeks, while TE grafts showed increasing collagen and DNA content, approaching native aorta levels over time.
- Histology revealed elastic fibers and endothelialization, and mechanical testing showed TE grafts approached native vessel properties; MMP-2 was detected in TE and native grafts.
Conclusions:
- Autologous tissue-engineered aortic grafts using a PGA-PHA copolymer can achieve biological characteristics similar to native aorta.
- This approach shows promise for developing functional,
- live
- vascular grafts for systemic circulation.