Antibody CD133 Biofunctionalization of Ammonium Acryloyldimethyltaurate and Vinylpyrrolidone Co-Polymer-Based Coating of the Vascular Implants.

Current vascular stents, such as drug eluting stents (DES), have some serious drawbacks, like in stent restenosis and thrombosis. Therefore, other solutions are sought to overcome these post-implantations complications. These include the strategy of biofunctionalization of the stent surface with antibodies that facilitate adhesion of endothelial cells (ECs) or endothelial progenitor cells (EPCs). Rapid re-endothelialization of the surface minimizes the risk of possible complications. In this study, we proposed ammonium acryloyldimethyltaurate/vinylpyrrolidone co-polymer-based surface (AVC), which was mercaptosilanized in order to expose free thiol groups. The presence of free thiol groups allowed for the covalent attachment of CD133 antibodies by disulfide bridges formation between mercaptosilanized surface and cysteine of the protein molecule thiol groups. Various examinations were performed in order to validate the procedure, including attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and Fourier transform Raman spectroscopy (FT-Raman), atomic force microscopy (AFM) and scanning electron microscopy (SEM). By means of ATR-FTIR spectroscopy presence of the CD133 antibody within coating was confirmed. In vitro studies proved good biocompatibility for blood cells without induction of hemolytic response. Thus, proposed biofunctionalized CD133 antibody AVC surface has shown sufficient stability for adapting as cardiovascular implant coating and biocompatibility. According to conducted in vitro studies, the modified surface can be further tested for applications in various biological systems.

Biogenic synthesis of silica nanoparticles from corn cobs husks. Dependence of the productivity on the method of raw material processing.

Corn processing generates thousands of tons of cob husks, which still contains many valuable elements. To make the most of these wastes, they are applied as substrates for biotransformation's procedures. This approach allowed converting or releasing, the elements deposited in the plant material and obtaining valuable products. Thus bioconversion of corn cob husks (CCH) using a fungus of the Fusarium culmorum genus resulted in obtaining silica nanoparticles of defined size and morphology. SEM analysis excluded their presence on the surface of the substrate. FTIR confirmed the presence of siloxane bonds and O-Si-O bonds in post-biotransformation fluid. Using the Heteropoly Blue Method, it was checked that the highest concentration of silica during 16-day biotransformation falls on the 7th day of the process, in which both the substrate sterilization and the process of the biocatalyst starvation were of key importance. Using the STEM and EDX analysis, it was proved that the obtained nanoparticles with a spherical form are structured and their dimensions are ~40 and ~70 nm. ICP-OES proved that the overall process efficiency was 47%. Such nanoparticles can be successfully used in the medical industry.

Functionalization with a VEGFR2-binding antibody fragment leads to enhanced endothelialization of a cardiovascular stent in vitro and in vivo.

Rapid endothelialization of cardiovascular stents is critical to prevent major clinical complications such as restenosis. Reconstruction of the native endothelium on the stent surface can be achieved by the capture of endothelial progenitor cells (EPCs) or neighboring endothelial cells (ECs) in vivo. In this study, stainless steel cardiovascular stents were functionalized with recombinant scFv antibody fragments specific for vascular endothelial growth factor receptor-2 (VEGFR2) that is expressed on EPCs and ECs. Anti-VEGFR2 scFvs were expressed in glycosylated form in Escherichia coli and covalently attached to amine-functionalized, titania-coated steel disks and stents. ScFv-coated surfaces exhibited no detectable cytotoxicity to human ECs or erythrocytes in vitro and bound 15 times more VEGFR2-positive human umbilical vein ECs than controls after as little as 3 min. Porcine coronary arteries were successfully stented with scFv-coated stents with no adverse clinical events after 30 days. Endovascular imaging and histology revealed coverage of the anti-VEGFR2 scFv-coated stent with a cell layer after 5 days and the presence of a neointima layer with a minimum thickness of 80 µm after 30 days. Biofunctionalization of cardiovascular stents with endothelial cell-capturing antibody fragments in this manner offers promise in accelerating stent endothelialization in vivo. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:213-224, 2020.

Photoactive Pore Matrix for In Situ Delivery of a Photosensitizer in Vascular Smooth Muscle Cells Selective PDT.

In this study we present the porous silica-based material that can be used for in situ drug delivery, offering effective supply of active compounds regardless its water solubility. To demonstrate usability of this new material, three silica-based materials with different pore size distribution as a matrix for doping with Photolon (Ph) and Protoporphyrin IX (PPIX) photosensitizers, were prepared. These matrices can be used for coating cardiovascular stents used for treatment of the coronary artery disease and enable intravascular photodynamic therapy (PDT), which can modulate the vascular response to injury caused by stent implantation-procedure that should be thought as an alternative for drug eluting stent. The FTIR spectroscopic analysis confirmed that all studied matrices have been successfully functionalized with the target photosensitizers. Atomic force microscopy revealed that resulting photoactive matrices were very smooth, which can limit the implantation damage and reduce the risk of restenosis. No viability loss of human peripheral blood lymphocytes and no erythrocyte hemolysis upon prolonged incubations on matrices indicated good biocompatibility of designed materials. The suitability of photoactive surfaces for PDT was tested in two cell lines relevant to stent implantation: vascular endothelial cells (HUVECs) and vascular smooth muscle cells (VSMC). It was demonstrated that 2 h incubation on the silica matrices was sufficient for uptake of the encapsulated photosensitizers. Moreover, the amount of the absorbed photosensitizer was sufficient for induction of a phototoxic reaction as shown by a rise of the reactive oxygen species in photosensitized VSMC. On the other hand, limited reactive oxygen species (ROS) induction in HUVECs in our experimental set up suggests that the proposed method of PDT may be less harmful for the endothelial cells and may decrease a risk of the restenosis. Presented data clearly demonstrate that porous silica-based matrices are capable of in situ delivery of photosensitizer for PDT of VSMC.

Functionalized CD133 antibody coated stent surface simultaneously promotes EPCs adhesion and inhibits smooth muscle cell proliferation-A novel approach to prevent in-stent restenosis.

We report a multistep strategy of biochemical surface modifications that resulted in the synthesis of new, effective and biocompatible intravascular implants coating with immobilized anti-CD133 antibodies, that proved to be the most effective in endothelial progenitor cells capture and reduced smooth muscle cells growth. Biomolecules were immobilized on differently functionalized surfaces. The distribution, nanostructural characteristics and intramolecular interactions of anti-CD133 molecules as well as their ability to bind EPCs was evaluated. We also tempted to build a molecular model of the CD133 protein to study antigen-antibody interactions. CD133 protein is expressed in endothelial progenitor cells (EPCs). Absence of preferential interaction site on CD133, but rather a presence of a small binding area, may be the specificity of reconnaissance sequence, thus importantly increasing the probability of CD133 protein binding. After all, regarding our molecular model, we are convinced that specific, and large enough interactions between anti-CD133 coating stent surface and CD133 present on EPCs will reduce risk of restenosis by favoring the endothelial growth. Additionally, the safety study of the vivo performance of modified titania based surface was performed using small animal models. No allergological or toxical local or systemic adverse effects of the developed coatings were noted.

Biocompatible Carbon-Based Coating as Potential Endovascular Material for Stent Surface.

Stainless steel 316L is a material commonly used in cardiovascular medicine. Despite the various methods applied in stent production, the rates of in-stent restenosis and thrombosis remain high. In this study graphene was used to coat the surface of 316L substrate for enhanced bio- and hemocompatibility of the substrate. The presence of graphene layers applied to the substrate was investigated using cutting-edge imaging technology: energy-filtered low-voltage FE-SEM approach, scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). The potential of G-316L surface to influence endothelial cells phenotype and endothelial-to-mesenchymal transition (EndoMT) has been determined. Our results show that the bio- and hemocompatible properties of graphene coatings along with known radial force of 316L make G-316L a promising candidate for intracoronary implants.

Nanosilica synthesis mediated by Aspergillus parasiticus strain.

Rice husks (RHs) are plant waste materials abundant in phytoliths silica bodies. These were used as starting material for fungal-mediated biotransformation leading to the synthesis of a high-value added product. A strain of Aspergillus parasiticus was capable of transforming the amorphous silica conglomerates into structured nanoparticles (NPs) in the process of RHs biotransformation. Silica NPs were produced extracellularly and their size ranged from 3 to 400 nm depending on the biotransformation conditions and the post-biotransformation supernatant processing. To characterize the NP's structure and dimension, SEM, STEM, EDX and FTIR technics were applied. These demonstrated and confirmed that pyramid (400 nm), cubical (85 nm) and spherical (3 nm and 24 ± 8 nm) forms of silica NPs were obtained.

Successful versus unsuccessful antegrade recanalization of single chronic coronary occlusion: eight-year experience and outcomes by a propensity score ascertainment.

AIMS: The effectiveness of revascularization of chronic total occlusion (CTO) remains intriguing. Thus, we sought to investigate whether a successful PCI for single CTO improves outcomes in a setting of stable angina and chronic occlusion of single coronary artery. METHODS AND RESULTS: Of 11 957 consecutive patients referred for nonurgent PCI between 2003 and 2010, 1110 displayed single CTO and were enrolled to the central CTO-registry database. The primary end-point included all-cause mortality, the secondary end-point a composite of safety outcome measure of all-cause death, nonfatal-MI, the need for urgent revascularization and stroke. The major adverse cardiovascular event (MACE) records were extracted from the national administrative database and all patients were linked to the long-term follow-up. Since the patient assignment was not random, we performed the propensity scoring to minimize selection bias; 734 patients (66%) had a successful PCI-CTO. Compared with successful procedures, unsuccessful procedures had similar rates of all-cause death both in crude (HR, 0.78; 95%CI, 0.49-1.25; P = 0.30) and adjusted analysis (HR, 0.80; 95%CI, 0.50-1.28; P = 0.34). A similar, significant reduction in overall MACE was noted with successful PCI-CTO compared with unsuccessful procedure in unadjusted (HR, 0.74; 95%CI, 0.56-0.96; P = 0.020) and adjusted calculation (HR, 0.73; 95%CI, 0.56-0.96; P = 0.019). Patients after successful PCI-CTO as compared with failed recanalization less frequently underwent surgical revascularization. The benefit was sustained at 3 years follow-up. CONCLUSIONS: Successful PCI for single CTO does not improve long-term survival, nonetheless, is associated with reduced overall MACE and the need for surgical revascularization.

Successful recanalisation of isolated chronic total occlusions improves outcomes in long-term observation: a case-control study.

BACKGROUND AND AIM: The long-term benefit of percutaneous recanalisation of chronic total occlusion (CTO) is still unclear. Given advances in interventional cardiology over the last two decades, we sought to investigate whether a successful percutaneous coronary intervention for CTO (PCI-CTO) improves outcomes in an age- and gender-matched single-centre cohort of stable angina patients. METHODS: Out of 401 consecutive patients enrolled to the CTO-Registry database, 276 patients were included in the final analysis. Patients with unsuccessful PCI-CTO (n = 138) were age- and gender-matched in a 1:1 ratio with patients who underwent a successful procedure. The primary end-points included hard end-points comprising death and nonfatal myocardial infarction (MI) and a composite safety outcome measure of death, nonfatal MI and ischaemia-driven revascularisation. The secondary end-point was improvement in angina status or complete resolution of angina symptoms. Patients were followed up for six months and at two years. RESULTS: Patients who underwent a successful recanalisation of CTO, compared to those who underwent an unsuccessful procedure, revealed similar rates of composite death and MI at six months (0.7% vs. 1.4%; hazard ratio [HR], 0.50; 95% confidence interval ratio [CI], 0.05-4.80; p = 0.56) and two years (1.4% vs. 5.8%; HR 0.24; 95% CI 0.07-0.85; p = 0.053). A significant difference in composite safety end-points between subsets, although not recorded after six months of observation (8.7% vs. 15.2%; HR 0.54; 95% CI 0.27-1.07; p = 0.095), was noted at two years follow-up (15.2% vs. 29.7%; HR 0.47; 95% CI 0.29-0.77; p = 0.004). A greater improvement in symptom burden or resolution of angina symptoms was documented after a successful PCI at both six months (68.1% vs. 23.2%, p < 0.001; 80.4% vs. 34.8%, p < 0.001, respectively) and two years (52.2% and 8.0%, p < 0.001; 68.1% vs. 22.5%, p < 0.001, respectively). CONCLUSIONS: Successful recanalisation of CTO improves outcomes in long-term observation.