A new method of primary engineering of esophagus using orthotopic in-body tissue architecture

Decellularized, Heparinized Small-Caliber Tissue-Engineered "Biological Tubes" for Allograft Vascular Grafts

There remains a lack of small-caliber tissue-engineered blood vessels (TEBVs) with wide clinical use. Biotubes were developed by electrospinning and in-body tissue architecture (iBTA) technology to prepare small-caliber TEBVs with promising applications. Different ratios of hybrid fibers of poly(l-lactic-co-ε-caprolactone) (PLCL) and polyurethane (PU) were obtained by electrospinning, and the electrospun tubes were then implanted subcutaneously in the abdominal area of a rabbit (as an in vivo bioreactor). The biotubes were harvested after 4 weeks. They were then decellularized and cross-linked with heparin. PLCL/PU electrospun vascular tubes, decellularized biotubes (D-biotubes), and heparinized combined decellularized biotubes (H + D-biotubes) underwent carotid artery allograft transplantation in a rabbit model. Vascular ultrasound follow-up and histological observation revealed that the biotubes developed based on electrospinning and iBTA technology, after decellularization and heparinization cross-linking, showed a better patency rate, adequate mechanical properties, and remodeling ability in the rabbit model. IBTA technology caused a higher patency, and the heparinization cross-linking process gave the biotubes stronger mechanical properties.

Circumferential Esophageal Reconstruction Using a Tissue-engineered Decellularized Tunica Vaginalis Graft in a Rabbit Model

BACKGROUND

Pediatric surgeons have faced esophageal reconstruction challenges for decades owing to a variety of congenital and acquired conditions. This work aimed to introduce a reproducible and efficient approach for creating tissue-engineered esophageal tissue using bone marrow mesenchymal stem cells (BMSCs) cultured in preconditioned mediums seeded on a sheep decellularized tunica vaginalis (DTV) scaffold for partial reconstruction of a rabbit's esophagus.

METHODS

DTV was performed using SDS and Triton X-100 solutions. The decellularized grafts were employed alone (DTV group) or after recellularization with BMSCs cultured for 10 days in preconditioned mediums (RTV group) for reconstructing a 3 cm segmental defect in the cervical esophagus of rabbits (n = 20) after the decellularization process was confirmed. Rabbits were observed for one month, after which they were euthanized, and the reconstructed esophagi were harvested for histological analysis.

RESULTS

Six rabbits in the DTV group and eight rabbits in the RTV group survived until the end of the one-month study period. Despite histological examination demonstrating that both grafts completely repaired the esophageal defect, the RTV graft demonstrated a histological structure similar to that of the normal esophagus. The reconstructed esophagi in the RTV group revealed the arrangement of the different layers of the esophageal wall with the formation of newly formed blood vessels and Schwann-like cells.

CONCLUSION

DTV xenograft is a novel scaffold that promotes cell adhesion and differentiation and might be effectively utilized for regenerating esophageal tissue, paving the way for future clinical trials in pediatric patients.

Successful reconstruction of the rat ureter by a syngeneic collagen tube with a cardiomyocyte sheet

Introduction

Ureteral injuries require surgical intervention as they lead to loss of renal function. The current reconstructive techniques for long ureteral defects are problematic. Consequently, this study aimed to reconstruct the ureter in a rat model using subcutaneously prepared autologous collagen tubes (Biotubes).

Methods

The lower ureter of LEW/SsNSlc rats was ligated to dilate the ureter to make anastomosis easier, and reconstruction was performed six days later by anastomosing the dilated ureter and bladder with a Biotube that was prepared subcutaneously in syngeneic rats. Some rats underwent left nephrectomy and ureter reconstruction simultaneously as negative controls to evaluate the effects of urine flow on patency. The other rats were divided into three groups as follows: a group in which the ureter was reconstructed with the Biotube alone, a group in which cardiomyocyte sheets made from the neonatal hearts of syngeneic rats were wrapped around the Biotube, and a group in which an adipose-derived stem cell sheets made from the inguinal fat of adult syngeneic rats were wrapped. Contrast-enhanced computed tomography and pathological evaluations were performed two weeks after reconstruction.

Result

In the Biotube alone group, all tubes were occluded and hydronephrosis developed, whereas the urothelium regenerated beyond the anastomosis when the left kidney was not removed, suggesting that urothelial epithelial spread occurred with urinary flow. The patency of the ureteral lumen was obtained in some rats in the cardiomyocyte sheet covered group, whereas stricture or obstruction of the reconstructed ureter was observed in all rats in the other groups. Pathological evaluation revealed a layered urothelial structure in the cardiomyocyte sheet covered group, although only a small amount of cardiomyocyte sheets remained.

Conclusion

Urinary flow may support the epithelial spread of the urothelium into the reconstructed ureter. Neonatal rat cardiomyocyte sheets supported the patency of the regenerated ureter with a layered urothelium.