Search Results (6)

Silk fibroin (SF) is a suitable material for vascular prostheses for small arteries. SF is useful not only as a base material for artificial vascular grafts but also as a coating material. This study prepared three types of transgenic SF (vascular endothelial growth factor (VEGF), Arg-Glu-Asp-Val (REDV), and Tyr-Ile-Gly-Ser-Arg (YIGSR)) incorporating expression factors that are thought to be effective for endothelialization as coating materials. We compared the contribution of these materials to early endothelialization in vivo when using them as a porous transgenic SF coating. A porous coating of transgenic SF containing VEGF, REDV, and YIGSR was applied to a silk small-diameter artificial vascular graft base with a diameter of 1.5 mm and a length of 3 cm. Two and four weeks after implantation of these artificial grafts into the abdominal aorta of rats, they were removed and evaluated by histologic examination. Transgenic SF coating incorporating VEGF and REDV demonstrated higher tissue infiltration and continuous endothelialization in the center of the graft compared to YIGSR at 4 weeks after implantation. VEGF and REDV are capable of endothelialization as early as 4 weeks after implantation, confirming the usefulness of transgenic SF when used as a porous coating. Full article

The covalent functionalization of synthetic peptides allows the modification of different biomaterials (metallic, polymeric, and ceramic), which are enriched with biologically active sequences to guide cell behavior. Recently, this strategy has also been applied to decellularized biological matrices. In this study, the covalent anchorage of a synthetic peptide (REDV) to a pericardial matrix decellularized via Schiff base is realized starting from concentrated peptide solutions (10⁻⁴ M and 10⁻³ M). The use of a labeled peptide demonstrated that as the concentration of the working solution increased, the surface density of the anchored peptide increased as well. These data are essential to pinpointing the concentration window in which the peptide promotes the desired cellular activity. The matrices were extensively characterized by Water Contact Angle (WCA) analysis, Differential Scanning Calorimetry (DSC) analysis, geometric feature evaluation, biomechanical tests, and preliminary in vitro bioassays. Full article

The present work aimed at the production and characterization of small caliber biomimetic and bioactive tubular scaffolds, which are able to favor the endothelialization process, and therefore potentially be suitable for vascular tissue engineering. The tubular scaffolds were produced using a specially designed mold, starting from a gelatin/gellan/elastin (GGE) blend, selected to mimic the composition of the extracellular matrix of native blood vessels. GGE scaffolds were obtained through freeze-drying and subsequent cross-linking. To obtain systems capable of promoting endothelization, the scaffolds were functionalized using two different bioactive peptides, Gly-Arg-Gly-Asp-Ser-Pro (GRGSDP) and Arg-Glu-Asp-Val (REDV). A complete physicochemical, mechanical, functional, and biological characterization of the developed scaffolds was performed. GGE scaffolds showed a good porosity, which could promote cell infiltration and proliferation and a dense external surface, which could avoid bleeding. Moreover, developed scaffolds showed good hydrophilicity, an elastic behavior similar to natural vessels, suitability for sterilization by an ISO accepted treatment, and an adequate suture retention strength. In vitro cell culture tests showed no cytotoxic activity against 3T3 fibroblasts. The functionalization with the REDV peptide favored the adhesion and growth of endothelial cells, while GRGDSP-modified scaffolds represented a better substrate for fibroblasts. Full article

This study describes a method for the modification of polyurethane small-diameter (5 mm) vascular prostheses obtained with the phase inversion method. The modification process involves two steps: the introduction of a linker (acrylic acid) and a peptide (REDV and YIGSR). FTIR and XPS analysis confirmed the process of chemical modification. The obtained prostheses had a porosity of approx. 60%, Young’s Modulus in the range of 9–11 MPa, and a water contact angle around 40°. Endothelial (EC) and smooth muscle (SMC) cell co-culture showed that the surfaces modified with peptides increase the adhesion of ECs. At the same time, SMCs adhesion was low both on unmodified and peptide-modified surfaces. Analysis of blood-materials interaction showed high hemocompatibility of obtained materials. The whole blood clotting time assay showed differences in the amount of free hemoglobin present in blood contacted with different materials. It can be concluded that the peptide coating increased the hemocompatibility of the surface by increasing ECs adhesion and, at the same time, decreasing platelet adhesion. When comparing both types of peptide coatings, more promising results were obtained for the surfaces coated with the YISGR than REDV-coated prostheses. Full article

The main objective of the present study was to assess the effects of sulfur (S) nutrition on plant growth, overall quality, secondary metabolites, and antibacterial and radical scavenging activities of hydroponically grown lettuce cultivars. Three lettuce cultivars, namely, Pazmanea RZ (green butterhead, V1), Hawking RZ (green multi-leaf lettuce, V2), and Barlach RZ (red multi-leaf, V3) were subjected to two S-treatments in the form of magnesium sulfate (+S) or magnesium chloride (−S). Significant differences were observed under −S treatments, especially among V1 and V2 lettuce cultivars. These responses were reflected in the yield, levels of macro- and micro-nutrients, water-soluble sugars, and free inorganic anions. In comparison with the green cultivars (V1 and V2), the red-V3 cultivar revealed a greater acclimation to S starvation, as evidenced by relative higher plant growth. In contrast, the green cultivars showed higher capabilities in production and superior quality attributes under +S condition. As for secondary metabolites, sixteen compounds (e.g., sesquiterpene lactones, caffeoyl derivatives, caffeic acid hexose, 5-caffeoylquinic acid (5-OCQA), quercetin and luteolin glucoside derivatives) were annotated in all three cultivars with the aid of HPLC-DAD-MS-based untargeted metabolomics. Sesquiterpene lactone lactucin and anthocyanin cyanidin 3-O-galactoside were only detected in V1 and V3 cultivars, respectively. Based on the analyses, the V3 cultivar was the most potent radical scavenger, while V1 and V2 cultivars exhibited antibacterial activity against Staphylococcus aureus in response to S provision. Our study emphasizes the critical role of S nutrition in plant growth, acclimation, and nutritional quality. The judicious-S application can be adopted as a promising antimicrobial prototype for medical applications. Full article

The paper presents a method of modifying the inner surface of nanofibrous vascular prostheses. The modification process involves two steps: introducing a hydrophilic linker, followed by a peptide containing the arginine-glutamic acid-aspartic acid-valine (REDV) sequence. The influence of the process parameters (reaction time, temperature, initiator concentration) on morphology and the distribution of fiber diameters were examined. For selected optimal parameters, the prostheses were modified in the flow system. Modifications along the entire length of the prosthesis were confirmed—the inlet and the outlet areas showed no significant (p > 0.05) differences in the value of the contact angle and the analyzed morphological parameters. The basic physicochemical and mechanical properties of modified prostheses were analyzed. The study showed that REDV-modified prosthesis has an average fiber diameter of 318 ± 99 nm, the average pore size of 3.0 ± 1.6 μm, the porosity of 48.4 ± 8.6% and Young’s modulus of 4.0 ± 0.4 MPa. The internal diameter of prostheses remains unchained and amounts to 3 mm. Such modified prostheses can reduce the risk of blood coagulation by increasing the surface’s wettability and, most of all, by introducing endothelial cell-selective peptide. As an effect, the proposed surfaces could recruit endothelial progenitor cells directly from the bloodstream and promote the endothelium formation after implantation. Full article