BACKGROUND:The chitosan-sulfated silk fibroin artificial blood vessel was obtained in our previous study. OBJECTIVE:To investigate the biocompatibility and function of the chitosan-sulfated silk fibroin artificial blood vessel replacement into the canine femoral artery. METHODS:Eight Beagles were randomly allotted to two groups, and chitosan-sulfated silk fibroin artificial blood vessel was implanted into the femoral artery (experimental group), but animalsin control group received no intervention. Six months after implantation, the coagulation function was detected, the vascular formation, including endothelial, smooth muscle and fibroblast layers were observed through hematoxylin-eosin staining under electron microscope. RESULTS AND CONCLUSION:(1) Hematoxylin-eosin staining showed that vascular endothelial cells, vascular smooth muscle cells and fibroblasts were found in the experimental group, which were similar with the normal vascular structures. (2) Immunohistochemistry:in the experimental group, there was a deeply stained band at the tissue edege through Factor Ⅷ staining, suggesting the formation of the endothelium;there were abundant brown particles precipitated in á-SMA staining, suggesting the vascular smooth muscle cel formation;Vimentin staining showed various brown particle precipitations indicating the fibroblast formation, and all were close to the normal vascular structures. (3) Electron microscope observed that the inner surface and section of the artificial vessel were similar with the normal one, and the three-layer structures formed in the section arranged irregularly. (4) There were no differences in the prothrombin time, activated partial thromboplastin time, thrombin time and fibrinogen between groups. To conclude, these results suggest that the chitosan-sulfated silk fibroin artificial blood vessel holds good biocompatibility and performances.

BACKGROUND:Cel purification can eliminate the biological variability of cel s, providing new insight into cel regeneration therapy. OBJECTIVE:To study the Influence of CD133+cel s on human umbilical cord blood mononuclear cel transplantation for treatment of heart failure. METHODS:Human cord blood mononuclear cel s were isolated using lymphocyte separation medium method, and CD133+and CD133-cel s were sorted using immunomagnetic beads at a cel density of 1×108/L. Forty Sprague-Dawley rats were randomized into five groups:sham group, model group, CD133+cel group, CD133-cel group and mononuclear cel group. Animal models of heart failure were made using intraperitoneal injection of isoproterenol in al the groups except for the sham group. Rats in the CD133+cel group and CD133-cel group were given 1 mL CD133+cel s plus 1 mL PBS and 1 mL CD133-cel s plus 1 mL PBS via the tail vein, respectively. Rats in the mononuclear cel group were given 1 mL CD133+cel s plus 1 mL CD133-cel s via the tail vein, and those in the sham and model groups given 2 mL PBS via the tail vein. After 4 weeks, cardiac pathology, degree of myocardial fibrosis and colonization of CD133+cel s in myocardial tissues were observed. RESULTS AND CONCLUSION:Hematoxylin-eosin staining showed that myocardial tissues arranged disorderly in the model group, but regularly in the sham group;myocardial disorders were mildest in the CD133+cel group, successively fol owed by the mononuclear cel group, and severest in the CD133-cel group and model group. Masson staining showed that in the model group, col agen fibers were proliferated, arranged irregularly and even broken, while in the sham group, the col agen fibers were less in number and arranged in order. Additional y, there was less reduction in col agen fibers and milder myocardial disorders in the CD133+cel group compared with the other groups. Area of col agen fibers was increased significantly in al the groups except for the sham group (P<0.05), but this increment was the minimal in the CD133+cel group. Findings from immunohistochemistry and immunofluorescence staining showed that there were no CD133+cel s in the myocardial tissues of rats. Therefore, our data indicate that compared with the mononuclear cel transplantation, CD133+cel transplantation exerts superiorities in relieving myocardial damage and reducing myocardial fibrosis. However, CD133+cel s are not colonized in the myocardial tissue after transplantation.