Acute Elution of TGFβ2 Affects the Smooth Muscle Cells in a Compliance-Matched Vascular Graft

Transforming growth factor beta 2 (TGFβ2) is a pleiotropic growth factor that plays a vital role in smooth muscle cell (SMC) function. Our prior in vitro work has shown that SMC response can be modulated with TGFβ2 stimulation in a dose dependent manner. In particular, we have shown that increasing concentrations of TGFβ2 shift SMCs from a migratory to a synthetic behavior. In this work, electrospun compliance-matched and hypocompliant TGFβ2-eluting tissue engineered vascular grafts (TEVGs) were implanted into Sprague Dawley rats for 5 days to observe SMC population and collagen production. TEVGs were fabricated using a combined computational and experimental approach that varied the ratio of gelatin:polycaprolactone to be either compliance matched or twice as stiff as rat aorta (hypocompliant). TGFβ2 concentrations of 0, 10, 100 ng/mg were added to both graft types ( n = 3 in each group) and imaged in vivo using ultrasound. Histological markers (SMC, macrophage, collagen, and elastin) were evaluated following explanation at 5 days. In vivo ultrasound showed that compliance-matched TEVGs became stiffer as TGFβ2 increased (100 ng/mg TEVGs compared to rat aorta, p