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DOI: 10.1055/s-2006-925637
Tissue engineering of autologous human heart valves for future use in congenital heart surgery
Objectives: Currently we are exploring the impact of cryopreserved human umbilical cord cells (CHUCCs) for the fabrication of tissue engineered heart valves for patients diagnosed prenatally with congenital heart lesions.
Methods: Human vascular cells were isolated from umbilical cords and cryopreserved. After 12 weeks the cryopreserved cells were again expanded in culture and characterized by immunohistochemistry. Polymeric heart valve scaffolds (P4HB) were sequentially seeded with CHUCCs (n=10). Five of the heart valves were grown for 7 days in a pulse duplicator and, as a control, five constructs were grown under static cell culture conditions for 7 days. Analysis of all tissue engineered heart valves included histology, immunohistochemistry, electron microscopy, functional analysis, and biomechanical examination.
Results: We found that CHUCCs remained viable after cryopreservation and showed a myofibroblast–like morphology. Histology of the tissue engineered heart valves showed layered tissue formation including connective tissue between the inside and the outside of the scaffold. Immunohistochemistry was positive for collagen, laminin and a-actin. Electron microscopy showed that the cells had grown into the pores and formed a confluent tissue layer during dynamic conditioning. Biochemical examination showed an increase of extracellular matrix in constructs after pulsatile flow compared to the static control group. Functional analysis demonstrated a physiological increase of the intracellular Ca2+ concentration of the conditioned constructs after stimulation with histamine.
Conclusion: The CHUCCs demonstrated growth potential and abilities of in-vitro tissue formation. These findings suggest the potential benefit of establishing autologous human cell banks for pediatric patients diagnosed intrauterinely with congenital defects.