Meanwhile, the grafts integrated well with the adjacent blood vessels, as demonstrated in Figure ?Figure3.3. using immunofluorescence staining with von Willebrand factor antibody. SP and SDF-1 grafts also promoted smooth muscle cell regeneration, endogenous stem cell recruitment, and blood vessel formation, which was the most prominent in the SP grafts. Evaluation of inflammatory response showed that 3 groups did not significantly differ in terms of the numbers of proinflammatory macrophages, whereas SP grafts showed significantly higher numbers of proremodeling macrophages than that of the control and SDF-1 grafts. Conclusions SDF-1 and SP grafts can be potential candidates for in situ vascular regeneration and are worthy for future investigations. values <0.05. Data are expressed as the mean SEM. Results Characterization of Electrospun Grafts Co-electrospinning has been widely used to fabricate scaffold materials because of its unique capacity for integrating the advantages of different polymer components into a graft. This study evaluated the potential of SP or SDF-1 peptides releasing grafts for in situ vascular tissue regeneration. Collagen was used as a mean to provide the sustained release of SP and SDF-1Cderived peptide. The processing parameters of PCL fibers have been optimized to fabricate macroporous and microfibrous grafts to facilitate cellularization and remodeling, which has been documented by us before.28 Our group has also previously optimized the electrospinning conditions to fabricate collagen fibers (data not shown), which were used to encapsulate SP and SDF-1Cderived peptides in this study. We envision WZB117 that collagen nanofibers will degrade in vivo resulting in the release of SP and SDF-1 peptides, which can enhance endogenous stem and progenitor cell mobilization and recruitment. Vascular grafts (inner diameter, 2.0 mm, wall thickness, 400C500 m) were fabricated by electrospinning, and the morphology was assessed by scanning electron microscopy. Uniform, continuous, and smooth fibers without bead defects and exhibiting a well-defined morphology were formed (Figure ?(Figure1).1). WZB117 The average diameter of microfibers was measured by using image J and found to be 7.0690.6159 m, 8.16070.5871 m, and 8.92461.031 m in control, SDF-1, and SP grafts, respectively (Figure ?(Figure11G). Open in a separate window Figure 1. Scanning electron microscope (SEM) micrographs of vascular grafts. Control (A, B), SDF (stromal cellCderived factor)-1 (C, D), and SP (substance P; E, F). Level pub, 30 m (A, C, E) and 15 m (B, D, F). The dietary fiber size was measured by using at least 100 materials per groups. The average diameter of microfibers was found to be 7.0690.6159 m, 8.16070.5871 m, and 8.92461.031 m in control, SDF-1, and SP grafts, respectively (G). H, Cell proliferation in vitro. Data are demonstrated as meanSD (n=5 per group) and evaluated by 1-way ANOVA followed by Tukey post hoc analysis. I, J, Photos of vascular grafts before implantation. K, Picture of an implanted graft. Col shows collagen; and PCL, polycaprolactone. We evaluated the in vitro launch of SP and SDF-1 peptides from electrospun membranes (n=5 per group) by using high-performance liquid chromatography, and the cumulative released amount of SP and SDF-1 peptides was found to be 57.799.96 and 68.7512.20%, respectively for up to 5 days. The release profile of SP and SDF-1 peptides offers been shown in Number I in the online-only Data Product. We did not observe the released amount of the peptides from electrospun membranes beyond this time point by using high-performance liquid chromatography, which may be caused by the detection limit of high-performance liquid chromatography (<0.1 ppm). Mechanical properties of control, SDF-1, and SP grafts including tensile strength, elongation at break, and Young modulus were identified and summarized in Number II in the online-only Data Product (n=5 WZB117 grafts per group). Tensile strength values were found to be 1.91290.1759, 1.81430.1149, and 1.80590.1994 WZB117 MPa for control, SDF-1, and Rabbit Polyclonal to MIPT3 SP grafts, respectively. Small modulus values were found to be 3.38430.6152, 3.09550.2069, and 3.33900.2351 MPa for control, SDF-1, and SP grafts, respectively. On the contrary, elongation at break ideals was found to be 585.75775.140, 585.6139.274, and 666.3083101.669% for WZB117 control, SDF-1, and SP grafts, respectively. The tensile strength, Young modulus, and elongation at break ideals of the native rat abdominal aorta were also measured and found to be 1.49410.061 MPa, 1.41670.145, and 160.50724.44%, respectively (Figure II in the online-only Data Product). These results indicate the control, SDF-1, and SP grafts did not significantly differ in terms of the mechanical properties. Cell Proliferation Assay Before in vivo implantation of the grafts, we assessed the viability of MSCs after attaching onto electrospun membranes. The cell growth was elucidated by using cell counting kit-8 for.