title: Implantation of a Tissue-Engineered Tubular Heart Valve in Growing Lambs.
abstract: Current pediatric heart valve replacement options are suboptimal because they are incapable of somatic growth. Thus, children typically have multiple surgeries to replace outgrown valves. In this study, we present the in vivo function and growth potential of our tissue-engineered pediatric tubular valve. The valves were fabricated by sewing two decellularized engineered tissue tubes together in a prescribed pattern using degradable sutures and subsequently implanted into the main pulmonary artery of growing lambs. Valve function was monitored using periodic ultrasounds after implantation throughout the duration of the study. The valves functioned well up to 8 weeks, 4 weeks beyond the suture strength half-life, after which their insufficiency index worsened. Histology from the explanted valves revealed extensive host cell invasion within the engineered root and commencing from the leaflet surfaces. These cells expressed multiple phenotypes, including endothelial, and deposited elastin and collagen IV. Although the tubes fused together along the degradable suture line as designed, the leaflets shortened compared to their original height. This shortening is hypothesized to result from inadequate fusion at the commissures prior to suture degradation. With appropriate commissure reinforcement, this novel heart valve may provide the somatic growth potential desired for a pediatric valve replacement.
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, 312 Church St SE, Minneapolis, MN, 55455, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Reimer
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, 312 Church St SE, Minneapolis, MN, 55455, USA.
authors.forename: Zeeshan
authors.initials: Z
authors.lastname: Syedain
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, 312 Church St SE, Minneapolis, MN, 55455, USA.
authors.forename: Bee
authors.initials: B
authors.lastname: Haynie
authors.affiliation: Experimental Surgical Services, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lahti
authors.affiliation: Experimental Surgical Services, University of Minnesota, Minneapolis, MN, USA.
authors.forename: James
authors.initials: J
authors.lastname: Berry
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, 312 Church St SE, Minneapolis, MN, 55455, USA. tranquil@umn.edu.|Department of Chemical Engineering and Material Science, University of Minnesota, Minneapolis, MN, USA. tranquil@umn.edu.
authors.forename: Robert
authors.initials: R
authors.lastname: Tranquillo
mesh_terms: D000818:Animals; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D012756:Sheep; D023822:Tissue Engineering
keywords: Congenital heart defects; Heart valve; Matrix remodeling; Pediatric; Tissue engineering