The success of artificial vascular graft in the host to obtain functional tissue regeneration and remodeling is a great challenge in the field of small diameter tissue engineering blood vessels. In our previous work, poly(ε-caprolactone) (PCL)/fibrin vascular grafts were fabricated by electrospinning. It was proved that the PCL/fibrin vascular graft was a suitable small diameter tissue engineering vascular scaffold with good biomechanical properties and cell compatibility. Here we mainly examined the performance of PCL/fibrin vascular graft in vivo. The graft showed randomly arranged nanofiber structure, excellent mechanical strength, higher compliance and degradation properties. At 9 months after implantation in the rat abdominal aorta, the graft induced the regeneration of neoarteries, and promoted ECM deposition and rapid endothelialization. More importantly, the PCL/fibrin vascular graft showed more microvessels density and fewer calcification areas at 3 months, which was beneficial to improve cell infiltration and proliferation. Moreover, the ratio of M2/M1macrophage in PCL/fibrin graft had a higher expression level and the secretion amount of pro-inflammatory cytokines started to increase, and then decreased to similar to the native artery. Thus, the electrospun PCL/fibrin tubular vascular graft had great potential to become a new type of artificial blood vessel scaffold that can be implanted in vivo for long term.

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A series of wound membranes of polyvinyl alcohol and recombinant spider silk protein (pNSR16) was prepared by electrospinning. The membrane was analyzed by scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy. The result showed that the three factors that affected average fiber diameter from high to low were, voltage, flow speed, and solidification distance; and the three factors that affected fiber uniformity from high to low were, flow speed, solidification distance, and voltage. The fibers adhered together after being dealt with alcohol. pNSR16 transformed from random coil into β-sheet after being immersed in alcohol. Additionally, the porosity of the electrospun membrane was 84.85%, which was higher than that of cast membrane prepared with the same composition. Experiments of applying electrospun membranes as wound dressing for Sprague Dawley rat wound healing showed that it could promote wound healing and basic fibroblast growth factor expression.

The development of tissue-engineered blood vessels provides a new source of donors for coronary artery bypass grafting and peripheral blood vessel transplantation. Fibrin fiber has good biocompatibility and is an ideal tissue engineering vascular scaffold, but its mechanical property needs improvement. Methods: We mixed polyurethane (PU) and fibrin to prepare the PU/fibrin vascular scaffolds by using electrospinning technology in order to enhance the mechanical properties of fibrin scaffold. We investigated the morphological, mechanical strength, hydrophilicity, degradation, blood and cell compatibility of PU/fibrin (0:100), PU/fibrin (5:95), PU/fibrin (15:85) and PU/fibrin (25:75) vascular scaffolds. Based on the results in vitro, PU/fibrin (15:85) was selected for transplantation in vivo to repair vascular defects, and the extracellular matrix formation, vascular remodeling, and immune response were evaluated. Results: The results indicated that the fiber diameter of the PU/fibrin (15:85) scaffold was about 712nm. With the increase of PU content, the mechanical strength of the composite scaffolds increased, however, the degradation rate decreased gradually. The PU/fibrin scaffold showed good hydrophilicity and hemocompatibility. PU/fibrin (15:85) vascular scaffold could promote the adhesion and proliferation of mesenchymal stromal cells (MSCs). Quantitative RT-PCR experimental results showed that the expression of collagen, survivin and vimentin genes in PU/fibrin (15:85) was higher than that in PU/fibrin (25:75). The results in vivo indicated the mechanical properties and compliance of PU/fibrin grafts could meet clinical requirements and the proportion of thrombosis or occlusion was significantly lower. The graft showed strong vasomotor response, and the smooth muscle cells, endothelial cells, and ECM deposition of the neoartery were comparable to that of native artery after 3 months. At 3 months, the amount of macrophages in PU/fibrin grafts was significantly lower, and the secretion of pro-inflammatory and anti-inflammatory cytokines decreased. Conclusion: PU/fibrin (15:85) vascular scaffolds had great potential to be used as smalldiameter tissue engineering blood vessels.

In this study, recombinant spider silk protein (pNSR16) was blended with polycaprolactone (PCL), gelatin (Gt), and chitosan (CS) to prepare (pNSR16/PCL/CS)/ (pNSR16/PCL/Gt) bilayer small-diameter vascular scaffold through electrospinning in order to imitate multilayer structure of natural vessel. The surface morphology and properties were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle, and mechanical tensile testing. The blood compatibility of scaffold was evaluated by recalcification coagulation time. Mesenchymal stem cells (MSC) were separated from SD rat bone marrow, and MTT assay was used to evaluate cell growth. Cell compatibility and interaction mechanism between bilayered vascular scaffold and MSC were studied. Subcutaneous implantation was performed to evaluate in vivo inflammatory reaction and degradation behavior. The preliminary results indicated that the scaffold fibers were relatively uniform, and hydrophilic performance and blood compatibility were good. The values of the tensile strength and elongation at break of vascular scaffold were 39 ± 2 MPa and 118 ± 4%, respectively. MSC morphology was uniform and spindle, whose steady growth period was reached on the fifth day. MSC adhered well and proliferated vigorously on vascular scaffold surface. A large number of MSC could migrate into (pNSR16/PCL/CS)/(pNSR16/PCL/Gt) scaffold interior. pNSR16 and Notch receptor had interaction function at protein level. The preparation of (pNSR16/PCL/CS)/(pNSR16/PCL/Gt) laid foundation for the construction of tissue engineering vessel.

RNA interference (RNAi) technology can achieve efficient and specific silencing of Caspase3 gene expression, thus providing new options for anti-apoptosis treatment. However, delivering siRNA to specific cells and tissues in...

ADMSCs were isolated from subcutaneous adipose tissue, characterized and cultured in vitro. GFP-labeled ADMSCs can grow and proliferate well on the Atelocollagen scaffolds, and induced by 5-aza the cells can differentiate into cardio-like cells. 3D cultured ADMSCs on Atelocollagen scaffolds were transplanted into mice ischemia myocardium, and have good biocompatibility with host cardio tissue.

Repopulation of decellularized vascular scaffolds (DVS) is limited because of change in the repertoire and ratios of the remaining extracellular matrix (ECM) proteins, for example, loss of glycoproteins and the retention of type I collagen. Pre-treatment of DVS with defined ECM proteins, which match the repertoire of integrin receptors expressed by the embryonic stem cells (mESCs) to be seeded, can increase the reseeding efficacy. mESCs mainly express high levels of functional receptors for LM and FN. Reseeding efficiency of DVS with mESCs was very low, but was sigficantly increased (2.5 ± 0.1 fold) by pre-treating the DVS with A549-conditioned media. In addition, pre-treatment with A549-conditioned media led to a more homogeneous distribution of the seeded mESCs throughout the engineered blood vessel as compared to untreated DVS. This paper may promote blood vessel engineering by stressing the importance of matching the cell binding motifs of DVS and the integrin receptor repertoire of seeded cells.