Abstract
Since the development of the first vascular grafts, fabrication of vessel replacements with diameters smaller than 6 mm remains a challenge. The present work aimed to develop PVA (poly (vinyl alcohol))-gelatin hybrids as tubes suitable for replacement of very small vessels and to evaluate their performance using a rat abdominal aorta interposition model. PVA-gelatin hybrid tubes with internal and external diameters of 1.4 mm and 1.8 mm, respectively, composed of 4 different gelatin ratios were prepared using a one-step strategy with both chemical and physical crosslinking. By 3D Time of Flight MRI, Doppler-Ultrasound, Computed Tomography angiography and histology, we demonstrated good patency rates with the 1% gelatin composition until the end of the study at 3 months (50% compared to 0% of PVA control grafts). A reduction of the patency rate during the time of implantation suggested some loss of properties of the hybrid material in vivo, further confirmed by mechanical evaluation until one year. In particular, stiffening and reduction of compliance of the PVA-gelatin grafts was demonstrated, which might explain the observed long-term changes in patency rate. These encouraging results confirm the potential of PVA-gelatin hybrids as ready-to-use vascular grafts for very small vessel replacement.
Highlights
Since the construction of the first tissue engineered blood vessels[1], using a Dacron mesh as support, there are still only two types of synthetic materials used in the clinic for vessel replacement, namely polyethylene terephtha
A
Combination of PVA and gelatin to form hybrid 3D prostheses aimed at taking advantage of the relevant mechanical and chemical properties of both materials
Summary
Since the construction of the first tissue engineered blood vessels[1], using a Dacron mesh as support, there are still only two types of synthetic materials used in the clinic for vessel replacement, namely polyethylene terephtha-. It is appropriate to develop ready-to-use materials that can be used as synthetic vascular grafts with diameters less than 6 mm. Numerous materials are being explored, to be used as vascular grafts for small vessel replacement, such as polycaprolactone[9], polylactide[10], bi-hybrid polyurethane/poly (ethylene terephthalate)[11], bacterial nanocellulose[12] and decellularized aorta from animals[13]. In the last years, promising results by our group[14] and others[15,16] have already been obtained for the development of vascular grafts based on poly (vinyl alcohol) (PVA). Graph represents average ± s.e.m.; *p < 0.05
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