Long-term outcomes of bovine pericardial patch angioplasty for recurrent stenosis in vascular access: A UK single-centre experience

Initial 3-year results of first human use of an in-body tissue-engineered autologous “Biotube” vascular graft for hemodialysis

This study presents the initial 3-year results of the first in-human study of internal shunt restoration using completely autologous vascular grafts, “Biotubes,” based on in-body tissue architecture. Biotubes (diameter, 6 mm; length, 7 cm) were prepared as autologous collagenous tubular tissues with approximately 0.5 mm wall thickness by embedding molds (two per patient), assembled with a silicone rod and a stainless steel pipe with many slits, into the patients’ abdominal subcutaneous tissue for 2 months. Two female patients with end-stage renal disease were undergoing hemodialysis with a high probability of failure due to repeated stenosis every few months at the venous outflow regions over 1.5 years. Biotubes formed in both patients and were bypassed over the venous stenosis region of the arteriovenous shunt. After bypass with Biotubes without living cells, palpable thrill and typical turbulent flow pattern were observed by pulsed-wave Doppler. Follow-up angiography showed no signs of dilation or stenosis after implantation, and puncture could be performed easily without graft damage. In both cases, stenosis of Biotubes occurred after 3–4 months. In the first case, percutaneous transluminal angioplasty was not required for over 2 years after implantation even after the development of Biotube stenosis. In the second case, stenosis at the proximal anastomotic site of the Biotube became prominent, and percutaneous transluminal angioplasty was needed 7 months after implantation and then repeated at up to 2 years. This was the first human study successfully supporting the concept of internal shunt restoration for hemodialysis using an autologous Biotube.

iBTA-induced bovine Biosheet for repair of abdominal wall defects in a beagle model: proof of concept

INTRODUCTION

We evaluated the usefulness of xeno-Biosheets, an in-body tissue architecture-induced bovine collagenous sheet, as repair materials for abdominal wall defects in a beagle model.

MATERIALS AND METHODS

Biosheets were prepared by embedding cylindrical molds into subcutaneous pouches of three Holstein cows for 2-3 months and stored in 70% ethanol. The Biosheets were 0.5 mm thick, cut into 2 cm × 2 cm, and implanted to replace defects of the same size in the abdominal wall of nine beagles. The abdominal wall and Biosheets were harvested and subjected to histological evaluation at 1, 3, and 5 months after implantation (n = 3 each).

RESULTS

The Biosheet and bovine pericardiac patch (control) were not stressed during the suture operation and did not split, and patches were easily implanted on defective wounds. After implantation, the patch did not fall off and was not perforated, and healing was observed nacroscopically in all cases. During the first month of implantation, accumulation of inflammatory cells was observed along with decomposition around the Biosheet. Decomposition was almost complete after 3 months, and the Biosheet was replaced by autologous collagenous connective tissue without rejection. After 5 months, the abdominal wall muscle elongated from the periphery of the newly formed collagen layer and the peritoneum was formed on the peritoneal cavity surface. Regeneration of almost all layers of the abdominal wall was observed. However, almost all pericardium patches were remained even at 5 months with inflammation.

CONCLUSION

Bovine Biosheets requiring no special post-treatment can be useful as off-the-shelf materials for abdominal wall repair.