Allogeneic myoblast cell sheet transplantation for esophageal wall reinforcement

BACKGROUND Using muscle flaps for reinforcing weakened tissue is an established technique that is widely used in the treatment of anastomotic leakage and intractable fistulas after esophagectomy. However, it has certain limitations including invasiveness and compromised cosmetic outcomes. Several studies have reported the efficacy of myoblast cell sheet transplantation in the prevention of digestive fistulas by reinforcing the gastrointestinal wall. However, its structural integrity and temporal changes after transplantation remain unclear. AIM To clarify the behavior of myoblast cell sheets and histological progression of wall reconstruction and alternative muscle flaps. METHODS Myoblast cell sheets were cultured for 7-10 days. In rats 67% of the abdominal esophageal muscle layers were removed. Myoblast cell sheets were transplanted to the resected site in the transplantation group while the control group received no transplantation. Body weight gain and histological evaluation were performed at weeks 1, 2, and 4 after surgery. RESULTS The fabricated myoblast cell sheets formed multilayered cell structures 50-μm thick with desmin-positive cells and Ki67-positive cells (Ki67 rate: 39.6% ± 6.8%). All esophageal wall resections and immediately subsequent myoblast cell sheet transplants were successful. Peritonitis was not observed in either group. At 4 weeks postoperatively, the transplant group showed a significantly higher rate of weight gain than the control group (67.8% ± 17.3% vs 44.7% ± 9.6%, P < 0.05). The transplantation group showed proliferating desmin-positive myoblasts 1 week postoperative and significantly thicker esophageal wall (1174.0 ± 177.0 μm vs 267.6 ± 257.6 μm, P < 0.05). The esophageal muscle layer thickness was not significantly different between the groups at 2 weeks and 4 weeks postoperative. CONCLUSION The short-term histological efficacy of allogeneic myoblast cell sheet transplantation for esophageal wall reinforcement was confirmed in an established rat model.