LAUSR

For decades, researchers have investigated the ideal material for clinical use in the cardiovascular field. Several substitute materials are used clinically, but each has drawbacks. Recently we developed biodegradable and elastic poly(ε-caprolactone-co-D,L-lactide) (P(CL-DLLA)) copolymers by adjusting the CL/DLLA composition, and evaluated the long-term efficacy and outcomes of these copolymers when used for right ventricular outflow tract (RVOT) replacement. This P(CL-DLLA) material was processed into a circular patch and used to replace a surgical defect in the RVOT of adult rats. Control rats were implanted with expanded polytetrafluoroethylene (ePTFE). Histologic evaluation was performed at 8, 24, and 48 weeks post-surgery. All animals survived the surgery with no aneurysm formation or thrombus. In all periods, ePTFE demonstrated fibrous tissue. In contrast, at 8 weeks P(CL-DLLA) showed infiltration of macrophages and fibroblast-like cells into the remaining material. At 24 weeks, P(CL-DLLA) was absorbed completely, and muscle-like tissue was present with positive staining for α-sarcomeric actinin and cardiac troponin T (cTnT). At 48 weeks, the cTnT-positive area had increased. The biodegradable and elastic P(CL-DLLA) induced cardiac regeneration throughout the 48-week study period. Future application of this material as a cardiovascular scaffold seems promising.