Vascular access animal models used in research

A Novel Hybrid Silk Fibroin/Polyurethane Arteriovenous Graft for Hemodialysis: Proof‐of‐Concept Animal Study in an Ovine Model

“…Notwithstanding that a direct comparison with commercially available arteriovenous grafts was not performed in this study, our finding is particularly significant considering that traditional 6 mm-diameter ePTFE grafts used as hemodialysis vascular accesses typically fail due to aggressive formation of intimal hyperplasia, and consequent stenosis with patency loss, at the venous anastomosis. [13,17] To address this critical aspect of arteriovenous shunting, several animal models have been developed over the last thirty years, [14,15] confirming that the primary unassisted patency of standard (5-6 mm in diameter) ePTFE grafts does not exceed 25% at 12 weeks in sheep [12,19] whereas secondary patency is approximately 67%. [20] In our study, deposition of endoluminal matrix of fibrotic and thrombotic origin was observed from day 30 to the end of the study along the graft length ( Figure 6; Figure S3, Supporting Information); however, this phenomenon, more accentuated close to the anastomoses (G1, G4, V2) than in the mid-graft region (G2-G3), did not result in a significant endoluminal stenosiswhose values stabilized at 25.06 ± 11.61% in V2 at 90 days-nor in a functional impairment, as confirmed by manual and ultrasound evaluation.…”

“…To address this critical aspect of arteriovenous shunting, several animal models have been developed over the last thirty years, [ 14,15 ] confirming that the primary unassisted patency of standard (5–6 mm in diameter) ePTFE grafts does not exceed 25% at 12 weeks in sheep [ 12,19 ] whereas secondary patency is approximately 67%. [ 20 ]…”

“…[12] Certainly, neointima proliferation at the venous anastomosis, leading to stenosis and thus reduced patency, is recognized as the most frequent cause of failure for arteriovenous grafts, in animals as in humans. [13][14][15] Reasoning that the ovine model indisputably shows comparative advantages in terms of available literature, capability of closely mimicking the human hemodynamics and pathophysiology, and ease of animal housing and handling, in this proof-ofconcept animal study we aimed at evaluating the performances of Silkothane grafts in a sheep model of arteriovenous shunt, with respect to patency and short-term graft remodeling. To this purpose, nine Silkothane grafts were implanted into nine sheep, as arteriovenous shunts between the common carotid artery and the ipsilateral external jugular vein, and were explanted at 30, 60, and 90 days (N = 3 for each group).…”

“…[ 12 ] Certainly, neointima proliferation at the venous anastomosis, leading to stenosis and thus reduced patency, is recognized as the most frequent cause of failure for arteriovenous grafts, in animals as in humans. [ 13–15 ]…”

A rat arteriovenous graft model using decellularized vein

“…Although there is a large body of work relating to decellularized conduits including studies in animal models 17,[33][34][35] and humans, 36,37 these models have typically been performed using large animals. This rodent AVG model is an easily performed small animal model; however, it does not fully mimic human conditions since it is not superficial but in the abdomen, and it cannot be punctured because of the small diameter.…”