One-year follow-up study of iBTA-induced allogenic biosheet for repair of abdominal wall defects in a beagle model: a pilot study

Application of Biosheets as Right Ventricular Outflow Tract Repair Materials in a Rat Model

Purposes

We report the experimental use of completely autologous biomaterials (Biosheets) made by “in-body tissue architecture” that could resolve problems in artificial materials and autologous pericardium. Here, Biosheets were implanted into full-thickness right ventricular outflow tract defects in a rat model. Their feasibility as a reparative material for cardiac defects was evaluated.

Methods

As the evaluation of mechanical properties of the biosheets, the elastic moduli of the biosheets and RVOT-free walls of rats were examined using a tensile tester. Biosheets and expanded polytetrafluoroethylene sheet were used to repair transmural defects surgically created in the right ventricular outflow tracts of adult rat hearts (n = 9, each patch group). At 4 and 12 weeks after the operation, the hearts were resected and histologically examined.

Results

The strength and elastic moduli of the biosheets were 421.3 ± 140.7 g and 2919 ± 728.9 kPa, respectively, which were significantly higher than those of the native RVOT-free walls (93.5 ± 26.2 g and 778.6 ± 137.7 kPa, respectively; P < 0.005 and P < 0.001, respectively). All patches were successfully implanted into the right ventricular outflow tract-free wall of rats. Dense fibrous adhesions to the sternum on the epicardial surface were also observed in 7 of 9 rats with ePTFE grafts, whereas 2 of 9 rats with biosheets. Histologically, the vascular-constructing cells were infiltrated into Biosheets. The luminal surfaces were completely endothelialized in all groups at each time point. There was also no accumulation of inflammatory cells.

Conclusions

Biosheets can be formed easily and have sufficient strength and good biocompatibility as a patch for right ventricular outflow tract repair in rats. Therefore, Biosheet may be a suitable material for reconstructive surgery of the right ventricular outflow tract.

Urinary bladder reconstruction using autologous collagenous connective tissue membrane "Biosheet®" induced by in-body tissue architecture: A pilot study

INTRODUCTION

In-body tissue architecture (iBTA) technology, based on cell-free tissue engineering, can produces collagenous tissues for implantation by subcutaneous embedding a designed mold. The aim of this study was to evaluate the biocompatibility of iBTA-induced "Biosheet®" collagenous sheets, as scaffold materials for bladder reconstruction.

METHODS

Canine Biosheet® implants were prepared by embedding molds into subcutaneous pouches in beagles for 8 weeks. A part of canine bladder wall was excised (2 × 2 cm) and repaired by patching the same sized autologous Biosheet®. The Biosheet® implants were harvested 4 weeks (n = 1) and 12 weeks (n = 3) after the implantation and evaluated histologically.

RESULTS

No disruption of the patched Biosheet® implants or urinary leakage into the peritoneal cavity was observed during the entire observation periods. There were no signs of chronic inflammation or Biosheet® rejection. The urine-contacting surface of luminal surface of the Biosheet® was covered with a multicellular layer of urothelium cells 4 weeks after implantation. α-SMA-positive muscle cells were observed at the margin of the Biosheet® implants at 12 weeks after the implantation. In addition, in the center of the Biosheet® implants, the formation of microvessels stained as α-SMA-positive was observed.

CONCLUSION

Biosheet® implants have biocompatibility as a scaffold for bladder reconstruction, indicating that they may be applicable for full-thickness bladder wall substitution. Further studies are required for definitive evaluation as a scaffold for bladder reconstruction.