Early in vivo experience with tissue-engineered heart valve leaflets from autologous bone marrow-derived cells

JIAN Xu-hua; LIN Qiu-xiong; QI Zhou-cuo; HUANG Zhi-feng; LUO Xin-lan

摘要：Background Currently used heart valve prostheses are associated with anticoagulation complications or limited durability.The advancement of stem cell study and tissue-engineered heart valve research may offer a relatively ideal solution to these problems.Methods Bone marrow was aspirated from sternum of lamb goats to isolate BMCs.Cells were identified by flow cytometry and its capacity of differentiation.Cellular viability was assessed with Rhdomine 123 staining.1 × 107cells were seeded on a patch of PGA sheet.After two-day in vitro culture,the autologous cell/scaffold sheets were used to replace the right posterior pulmonary valve leaflets under cardiopulmonary bypass.The leaflets were explanted at 2 days,2,6,8 and 10 weeks after implantation.The samples were examined macroscopically,histologically,immunohistochemically,and by Scanning Electron Microscope (SEM).Two goats were implanted with acellular sheets and established as a control group.Results BMCs exhibited fibroblastoid morphology with good viability.Flow cytometry showed negative CD14 and CD45 expression.In vitro cultured BMCs demonstrated the potential to differentiate into adipocytes.The explanted leaflets resembled the characteristics of native leaflets macroscopically in the cellular group. Histology showed extracellular matrix was synthesized and cells were distributed in the single-layered leaflets.Immunohistochemistry revealed positive staining for von Willebrand factor,α-SMA,vimentin.A confluent cell surface was formed on the explanted TEHLs.No calcium deposited on the leaflets.In control group,the acellular scaffolds were completely degraded,without leaflet remained at 8weeks.Conclusions It is possible to create tissue-engineered heart valves in vivo using autologous bone marrow-derived cells.