Pre‐implantation evaluation of a small‐diameter, long vascular graft (Biotube®) for below‐knee bypass surgery in goats

Abstract

There are no small-diameter, long artificial vascular grafts for below-knee bypass surgery in chronic limb-threatening ischemia. We have developed tissue-engineered vascular grafts called "Biotubes ® " using a completely autologous approach called in-body tissue architecture (iBTA). This study aimed at pre-implantation evaluation of Biotube and its in vivo preparation device, Biotube Maker, for use in below-knee bypass surgery. Forty nine makers were subcutaneously embedded into 17 goats for predetermined periods (1, 2, or 3 months). All makers produced Biotubes as designed without inflammation over all periods, with the exception of a few cases with minor defects (success rate: 94%). Small hole formation occurred in only a few cases. All Biotubes obtained had an inner diameter of 4 mm and a length of 51 to 52 cm with a wall thickness of 594 ± 97 μm. All Biotubes did not kink when completely bent under an internal pressure of 100 mmHg and did not leak without any deformation under a water pressure of 200 mmHg. Their burst strength was 2409 ± 473 mmHg, and suture retention strength was 1.75 ± 0.27 N, regardless of the embedding period, whereas tensile strength increased from 7.5 ± 1.3 N at 1 month to 9.7 ± 2.0 N at 3 months with the embedding period. The amount of water leakage from the needle holes prepared in the Biotube wall was approximately 1/7th of that in expanded polytetrafluoroethylene vascular grafts. The Biotubes could be easily connected to each other without cutting or anastomosis leaks. They could be stored for at least 1 year at room temperature. This study confirmed that even Biotubes formed 1 month after embedding of Biotube Makers had properties comparable to arteries.biotube, chronic limb-threatening ischemia, in body tissue architecture, small diameter vascular graft, tissue engineering | INTRODUCTIONPatients with chronic limb-threatening ischemia (CLTI) present with resting pain, foot ulcer, or gangrene. Due to the severity of the disease, hundreds of thousands of patients worldwide undergo lower limb amputations each year. 1 The prognosis after amputation is extremely poor, with a mortality rate of 30-50% and a contralateral leg amputation rate of 25% within 1 year, which is a life-threatening

Antioxidant and Trilayered Electrospun Small-Diameter Vascular Grafts Maintain Patency and Promote Endothelialisation in Rat Femoral Artery

“…The suture retention strength of the grafts (4.34 ± 0.18 N) was higher than the saphenous vein and internal mammary artery but similar to that of other tissue-engineered vascular grafts in the literature. 47,48 Greater suture retention strength further supports the utility of the material for surgical applications. The burst pressure calculated for the PU− PGACL + GA grafts was 2585.75 ± 80 mmHg, which was greater than the minimum requirement of a vascular graft (1700 mmHg).…”

Carotid Artery Bypass Surgery of In-Body Tissue Architecture-Induced Small-Diameter Biotube in a Goat Model: A Pilot Study

“…The resulting Biotubes were 40 cm and 55 cm in length, with a 4 mm inner diameter and a 0.85 mm wall thickness. The thinness of Biotubes for clinical use while maintaining strength was considered at the mold design stage [ 7 ]. The Biotube makers were embedded subcutaneously in the abdomen of six Saanen goats (age: ≥12 months, weight: 39–70 kg; 4–6 molds per animal).…”

“…The sample used to determine tensile strength was 5 mm in width, and six samples were collected from each Biotube graft for evaluation. The method of these strength tests followed the previous literature [ 7 ].…”

“…Therefore, such patients have long awaited the advent of tissue-engineered vascular grafts (TEVGs) [ 7 , 8 , 9 , 10 ]. Among TEVGs, Biotubes are grafts developed from the patient’s body tissues based on in-body tissue architecture (iBTA) technology and are considered close to clinical application because of their biocompatibility and versatility in graft preparation [ 7 ]. Biotubes are autologous collagenous tubes obtained through a biological reaction to molds implanted subcutaneously, which is an encapsulation reaction [ 11 ].…”

Successful tracheal regeneration using biofabricated autologous analogues without artificial supports

“…In a separate study, we developed an in vivo tissue engineering technique called the in-body tissue architecture (iBTA). We prepared iBTA-induced tissues of various shapes and sizes, such as a tubular tissue called Biotube for vascular grafts 12 , 13 , sheet-like tissue called Biosheet for cornea 14 , aortic valve leaflets 15 , myocardium 16 , and others, and a more complex heart valve-like tissue called Biovalve 17 . The Biotube has already been clinically applied as an alternative blood vessel for bypass to a chronic limb-threating ischemia patient 13 or hemodialysis patients.…”