Fetal tissue engineering: Diaphragmatic replacement

Background/Purpose: Prosthetic repair of congenital diaphragmatic hernia has been associated with high complication rates. This study was aimed at applying fetal tissue engineering to diaphragmatic replacement. Methods: Fetal lambs underwent harvest of skeletal muscle specimens. Once expanded in vitro, fetal myoblasts were suspended in a collagen hydrogel submitted to controlled radial tension. The construct was then placed in a bioreactor. After birth, all animals underwent creation of 2 diaphragmatic defects. One defect was repaired with the autologous-engineered construct placed in between 2 acellular supporting membranes and the other with an identical construct but without any cells. Each animal was its own control (graft, n = 10). Animals were killed at different time-points postimplantation for histologic examination. Statistical analysis was by analysis of variance (ANOVA). Results: Fetal myoblasts expanded up to twice as fast as neonatal cells. Hydrogel-based radial tension enhanced construct architecture by eliciting cell organization within the scaffold. No eventration was present in 4 of 5 engineered constructs but in 0 of 5 acellular grafts (P < .05). At harvest, engineered constructs were thick and histologically resembled normal skeletal muscle, whereas acellular grafts were thin, floppy, and showed low cell density with increased fibrosis. Conclusions: Unlike acellular grafts, engineered cellular diaphragmatic constructs are anatomically and histologically similar to normal muscle. Fetal tissue engineering may be a viable alternative for diaphragmatic replacement. J Pediatr Surg 36:146-151. Copyright (C) 2001 by W.B. Saunders Company.