Abstract:Biocompatibility and biomechanical stability are two of the main obstacles limiting the effectiveness of vascular scaffolds. To improve the biomechanical stability and biocompatibility of these scaffolds, we created a heparin-nanomodified acellular bovine jugular vein scaffold by alternating linkage of heparin and dihydroxy-iron via self-assembly. Features of the scaffold were evaluated in vitro and in vivo. Heparin was firmly linked to and formed nanoscale coatings around the fibers of the scaffold, and the a… Show more
“…And at week 12, the amounts obtained for modified and unmodified scaffolds were 11.97 ± 2.48 and 337.53 ± 25.99 μg/mg dry weight, respectively (Fig. 5), being in agreement to previously reported results 36 . There was a significant difference in calcium content between the heparinized and non-heparinized scaffolds at both time points (P < 0.01), indicating the advantage of H-CSVSs for in vivo vascular regeneration.Figure 5Column graph of calcification behavior of heparinized and non-heparinized silk scaffolds in vivo .…”
Section: Resultssupporting
confidence: 92%
“…To overcome this challenge, heparin, a widely used anticoagulant biopolymer, has been used in numerous vascular engineering applications 8, 23, 35, 36, 50 . To achieve the desired outcome, the heparin must exist at the blood-material interface in an adequate dose for a sufficient period.…”
Autologous grafts, as the gold standard for vascular bypass procedures, associated with several problems that limit their usability, so tissue engineered vessels have been the subject of an increasing number of works. Nevertheless, gathering all of the desired characteristics of vascular scaffolds in the same construct has been a big challenge for scientists. Herein, a composite silk-based vascular scaffold (CSVS) was proposed to consider all the mechanical, structural and biological requirements of a small-diameter vascular scaffold. The scaffold’s lumen composed of braided silk fiber-reinforced silk fibroin (SF) sponge covalently heparinized (H-CSVS) using Hydroxy-Iron Complexes (HICs) as linkers. The highly porous SF external layer with pores above 60 μm was obtained by lyophilization. Silk fibers were fully embedded in scaffold’s wall with no delamination. The H-CSVS exhibited much higher burst pressure and suture retention strength than native vessels while comparable elastic modulus and compliance. H-CSVSs presented milder hemolysis in vitro and significant calcification resistance in subcutaneous implantation compared to non-heparinized ones. The in vitro antithrombogenic activity was sustained for over 12 weeks. The cytocompatibility was approved using endothelial cells (ECs) and vascular smooth muscle cells (SMCs) in vitro. Therefore, H-CSVS demonstrates a promising candidate for engineering of small-diameter vessels.
“…And at week 12, the amounts obtained for modified and unmodified scaffolds were 11.97 ± 2.48 and 337.53 ± 25.99 μg/mg dry weight, respectively (Fig. 5), being in agreement to previously reported results 36 . There was a significant difference in calcium content between the heparinized and non-heparinized scaffolds at both time points (P < 0.01), indicating the advantage of H-CSVSs for in vivo vascular regeneration.Figure 5Column graph of calcification behavior of heparinized and non-heparinized silk scaffolds in vivo .…”
Section: Resultssupporting
confidence: 92%
“…To overcome this challenge, heparin, a widely used anticoagulant biopolymer, has been used in numerous vascular engineering applications 8, 23, 35, 36, 50 . To achieve the desired outcome, the heparin must exist at the blood-material interface in an adequate dose for a sufficient period.…”
Autologous grafts, as the gold standard for vascular bypass procedures, associated with several problems that limit their usability, so tissue engineered vessels have been the subject of an increasing number of works. Nevertheless, gathering all of the desired characteristics of vascular scaffolds in the same construct has been a big challenge for scientists. Herein, a composite silk-based vascular scaffold (CSVS) was proposed to consider all the mechanical, structural and biological requirements of a small-diameter vascular scaffold. The scaffold’s lumen composed of braided silk fiber-reinforced silk fibroin (SF) sponge covalently heparinized (H-CSVS) using Hydroxy-Iron Complexes (HICs) as linkers. The highly porous SF external layer with pores above 60 μm was obtained by lyophilization. Silk fibers were fully embedded in scaffold’s wall with no delamination. The H-CSVS exhibited much higher burst pressure and suture retention strength than native vessels while comparable elastic modulus and compliance. H-CSVSs presented milder hemolysis in vitro and significant calcification resistance in subcutaneous implantation compared to non-heparinized ones. The in vitro antithrombogenic activity was sustained for over 12 weeks. The cytocompatibility was approved using endothelial cells (ECs) and vascular smooth muscle cells (SMCs) in vitro. Therefore, H-CSVS demonstrates a promising candidate for engineering of small-diameter vessels.
“…As reported previously, the overall patency rate of the acellular small intestinal submucosa (SIS) was 75% (within 48 weeks), the graft rupture rate was 5% (within 21 days), and aneurysmal dilatation was found in 11% of grafts (8). The poor biomechanical stability of the acellular bovine jugular vein scaffolds results in thrombus formation, aneurysm formation, and calcification, limiting the clinical effectiveness of these scaffolds (9)(10)(11). Decellularized porcine saphenous arteries showed limited patency rates of 60% at 1 month and 50% at 3 months (12).…”
mentioning
confidence: 82%
“…The endothelium also plays a direct role in the regulation of the coagulation cascade and thus thrombosis (3). The poor biomechanical stability of the acellular bovine jugular vein scaffolds results in thrombus formation, aneurysm formation, and calcification, limiting the clinical effectiveness of these scaffolds (9)(10)(11). When the cells were seeded onto scaffolds and cultured in a static setting, the seeding efficiencies were approximately 10-25% (5).…”
We aimed to investigate whether acellular endocardium can be used as a useful biomaterial for the intima of engineered small-caliber vascular grafts. Fresh endocardium was harvested from the swine left atrium and was decellularized by digestion with the decellularization solution of Triton X-100 and SDS containing DNase I and RNase A. Surface morphological characteristics and Young's modulus were evaluated. To analyze the effect of mechanical characteristics on cell adhesion, the decellularized endocardium was stiffened with 2.5% glutaraldehyde. Small-caliber vascular grafts were constructed using decellularized endocardium treated with or without glutaraldehyde as the intima. CD34+ cells were seeded onto the luminal surface of the vascular grafts and linked to bioreactors that simulate a pulsatile blood stream. Acellular endocardium had distinct surface morphological characteristics, which were quite different from those of other materials. The compliance of acellular endocardium was higher than that of other materials tested by Young's modulus. CD34+ cells formed a monolayer structure and adhered to the inner face of the acellular endocardium. The glutaraldehyde treatment stiffened the acellular endocardium but had little impact on the surface morphological characteristics or static adhesiveness of the cells. Data from the bioreactor study showed that the detachment of the cells from the surface of glutaraldehyde-treated acellular endocardium increased dramatically when the pressure was equal or higher than 40 mm Hg, while the cells on the untreated acellular endocardium remained well and formed confluent monolayers and tight junctions under the same pressure. Acellular endocardium has distinct structures and mechanical characteristics that are beneficial for CD34+ cell adhesion and retention under dynamic fluid perfusion. Thus, it can be used as a useful biomaterial for the construction of the intima of engineered small-caliber vascular grafts.
“…All fasting for at least 8 h and after that peripheral venous blood samples were collected in the morning from all participants who were still in a recumbent position (Zhu, Zou, Xiong, & Zhang, ). Venous blood (5 mL) was drawn into an EDTA containing tube and then within 30 min the sample was centrifuged at 3000 rpm for 15 min to obtain the serum, which was then stored at −80 °C refrigerator (Tao, Hu, & Wu, ). Serum UA (SUA), total cholesterol (TC), triglycerides (TG), high‐density lipoprotein cholesterol (HDL), low‐density lipoprotein cholesterol (LDL), blood urea nitrogen (BUN), and serum creatinine (Scr) were determined with commercial kits and an automatic blood cell analyzer (Hitachi 747; Hitachi, Tokyo, Japan) at the central laboratory of Taishan Medical University Affiliated Taishan Hospital.…”
ObjectiveMounting evidence suggests that oxidative stress is involved in the pathogenesis of vascular dementia (VD). Uric acid (UA) has long been implicated as a critical cause of cardiovascular disease. Nevertheless, UA was also expected to play an important role in antioxidant and neuroprotection recently. We hypothesized that UA may have a protective role against VD. The aim of this study was to investigate the link between serum UA and cognitive dysfunction in VD.Materials and MethodsThere were altogether 127 VD subjects and 81 nondemented controls enrolled in our study. Serum UA, demographic, and clinical characteristics were recorded at baseline, and all participants underwent Mini‐Mental State Examination (MMSE) at the beginning of the trial.ResultsThe VD group showed lower MMSE scores and serum UA levels than nondemented controls and there was significant statistical difference between the two groups (p < .05). Demographic and clinical characteristics such as age, gender, education, body mass index (BMI), total cholesterol (TC), triglycerides (TG), high‐density lipoprotein cholesterol (HDL), low‐density lipoprotein cholesterol (LDL), blood urea nitrogen (BUN), and serum creatinine (Scr) did not differ dramatically between groups (p > .05). In VD subjects, there was a positive correlation between serum UA and MMSE scores (r = .32, p < .05), and this correlation was independent of demographic and clinical characteristics (β = .272, p < .05).Conclusions
VD subjects have dramatically lower serum UA levels in comparison to nondemented controls. Lower serum UA levels are linked to cognitive dysfunction and could serve as a potential predictor for VD.
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