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The failure of heart valve bioprostheses, requiring repeated intervention to replace them, is a serious drawback that narrows the scope of such devices. The present study demonstrates the experimental investigation of a medical device designed to partially solve the problem of repeated interventions on heart valves, primarily with an emphasis on reducing the duration and trauma of such procedures due to the sutureless balloon implantation method of the «valvein- valve» method.Material and methods. The paper presents a series of in silico, in vitro and in vivo experiments to evaluate various aspects of the device under development. Numerical modeling of the final shape setting to the supporting frame of the heart valve prosthesis to select the most promising concept for prototyping was carried out in the Abaqus/CAE (Dassault Systèmes, France) based on the finite element method. The selected optimal support frame model was prototyped in the form of a series of prosthesis samples of four standard sizes for hydrodynamic studies of quantitative characteristics in vitro. The study was carried out in the Vivitro Labs unit (Vivitro Labs, Canada), imitating the physiological mode of the heart, the prostheses were examined for the mitral position. The developed prototypes of the device were supplemented with related products, an implant holder and a balloon catheter, after which the proposed method of sutureless fixation was validated in an in vitro implantation procedure on a bovine heart model and a series of in vivo (n = 3) chronic experiments on animals.Results. In the course of numerical simulation, it was shown that in Model No. 3 of the supporting frame of the prosthesis, the smallest stresses occur – with an amplitude of up to 490 MPa. For other concepts (Models No. 1 and No. 2), this indicator was significantly higher, 543 and 514 MPa, respectively. Prototypes obtained on the basis of the selected shape of the support frame demonstrated satisfactory hydrodynamic characteristics: effective hole area 190-261 mm2, regurgitation volume 6–9 ml/cycle, average transprosthetic gradient 4.4–6.4 mmHg, depending on size. The study of the technology of sutureless balloon implantation in an in vitro model of the heart and the subsequent chronic experiment on sheep confirmed the main idea of the system – the possibility of a significant reduction in the duration of repeated prosthetics. It has been shown that the time of suture implantation of the “classic” frame prosthesis of the mitral valve is 23–29 minutes, with a total access time of 41–52 minutes. When implanting the experimental device, the sutureless prosthesis itself took 4–6 minutes, access time 24–29 minutes. At the same time, one-month results of an echocardiographic study of the operation of the prosthesis demonstrated satisfactory hemodynamics.Conclusions. This work demonstrates a consistent series of tests of the system being developed for repeated heart valve replacement, which substantiates some design solutions, confirms the effectiveness and viability of the chosen approach to sutureless minimally invasive implantation.

Background. The study of explanted heart valve bioprostheses is a valuable source of information about the destructive processes in their components that develop as a result of prolonged contact with the recipient’s body. An analysis of the morphology, staging and degree of involvement of various valve prosthesis materials in the prevalence of pathological processes – calcification, mechanical damage, growth of the connective tissue capsule, is the basis for developing potential methods for increasing the service life of these products and reducing the risk of re-interventions. The aim of the study was to evaluate the potential of computed microtomography to analyze the internal structure of a biological prosthetic heart valve explanted due to dysfunction. Material and methods. In this work, we investigated the prevalence of pathological mineralization of the PeriCor bioprosthesis, explanted as a result of the developed dysfunction of the leaflet apparatus with a clinical picture of grade 2B prosthetic insufficiency. The material was described macroscopically, after which it was subjected to high-resolution computed microtomography. In the structure of the sample, X-ray dense areas of pathological mineralization were identified and described, and the volume of the material involved in calcification was assessed. Results. It was shown that the main pathological changes that led to prosthetic dysfunction were degenerative changes in the biomaterial with signs of calcification, thickening and rupture of the leaflets. It was quantitatively determined that the areas of radiologically dense inclusions (calcifications) occupy 11.1 % of the volume of the material. It has been established that the described areas are associated with the sheathing of the frame and with the elements of the suture material used in the production of this bioprosthesis. Conclusion. The method of non-destructive analysis of the internal structure of altered materials of a biological prosthesis studied in this work has demonstrated the possibility of а qualitative and quantitative assessment of areas of pathological mineralization, their distribution and connection with other processes leading to the development of prosthetic dysfunction. The method makes it possible to visualize macro- and microsites of calcification and can become a valuable tool to complement existing approaches to the study of explanted bioprostheses.

Calcification of biomaterials used in prosthetic heart valves has been a challenging issue in cardiovascular surgery. The objective of this work is to compare the efficiency of polyvinyl alcohol (PVA) and tannic acid (TA) modification of xenomaterials, pre-stabilized with glutaraldehyde (GA) and ethylene glycol diglycidyl ether (EGDE), in reducing calcification. Analysis of mechanical properties evaluated under uniaxial tension, showed a significant increase in the tensile strength of the test samples compared to the control (unmodified) samples (p < 0.05). Additional treatment of GA-fixed tissue with PVA and TA significantly reduced the amount of calcium in the samples implanted into rats for a 60-day follow-up (p < 0.05). The level of calcification of samples prestabilized with EGDE and treated with PVA and TA did not differ from the control group (p = 0.063). Cumulative analysis of the study results demonstrated that the GA-fixed biomaterial modified with PVA and TA can reduce calcium-binding activity and increase strength. This indicates the prospects for clinical application of the proposed treatment methods. This being said, the issue of long-term body response requires further study of the long-term stability of the modified biomaterial under physiologic blood flow conditions.

The aim of the study was an in vitro hydrodynamic study of the developed prosthetic heart valve of the second generation, designed to carry out an implantation using «valve-in-valve» method. Material and methods. Prototypes of the developed prosthesis were studied under simulated physiological conditions of the heart using a Vivitro Labs pulse duplicator (Canada) in a comparative aspect with «UniLine» clinical commercial aortic valve bioprosthesis (Russia). Samples were tested by simulating sutureless implantation procedure. Results. The developed valves showed satisfactory hydrodynamic characteristics – for all cases of «implantation» from the position of the average trans-prosthetic gradient (6.1–11.1 mm Hg) and the effective orifice area (1.60–1.81 cm2 ). The analysis of the regurgitation fraction allowed us to determine the optimal sizes for implantation using «valvein-valve» method, which subsequently will form the basis of sizing guidelines for size selection. A qualitative analysis of the leaflet’s work demonstrated the presence of slight asymmetry for a number of prostheses – in case of mismatch of sizes when simulating «valve-in-valve» procedure. Conclusion. The tests demonstrate the viability of the developed design from the standpoint of hydrodynamic efficiency and determines the basic rules of selecting a prosthesis for reimplantation relative to the primary valve.

Objective: to study the effect of various types of suture materials, potentially suitable for cardiovascular surgery, on experimental surgical outcomes. Materials and methods. Polypropylene sutures (Prolene 6/0), titanium nickelide (TiNi) sutures (6/0) and absorbable polydioxanone sutures (Monoplus 6/0) were used in the study. Male Wistar rats were used for in vivo studies. The effect of suture materials on abdominal adhesions was studied. In vivo calcification process was examined, and response of blood components in contact with suture materials was also assessed in vitro. Results. There is a negative inflammatory response to suture materials. The severity of this response depended on the type of material used. Polypropylene sutures demonstrated the most severe inflammatory response provoking massive adhesion formation. In addition, large calcium deposits were found both in the suture area and in the thickness of the biomaterial, stitched with prolene and implanted subcutaneously in the rats. Titanium nickelide sutures showed high hemocompatibility and biocompatibility. The Monoplus sutures caused minimal inflammatory response and provoked calcification of the biomaterial to a lesser degree. Conclusion. The suture material could have significant effects on surgical outcomes and could cause postoperative complications.

Implantation of polymeric heart valves can solve the problems of existing valve substitutes – mechanical and biological. Objective: to comprehensively assess the hemocompatibility of styrene-isobutylene-styrene (SIBS) triblock copolymer, synthesized by controlled cationic polymerization in comparison with expanded polytetrafluoroethylene (ePTFE) used in clinical practice. Materials and methods. SIBS-based films were made by polymer solution casting method; in vitro biocompatibility assessment was performed using cell cultures, determining cell viability, cell adhesion and proliferation; tendency of materials to calcify was determined through in vitro accelerated calcification; in vivo biocompatibility assessment was performed by subcutaneous implantation of rat samples; hemocompatibility was determined ex vivo by assessing the degree of hemolysis, aggregation, and platelet adhesion. Results. The molecular weight of synthesized polymer was 33,000 g/mol with a polydispersity index of 1.3. When studying cell adhesion, no significant differences (p = 0.20) between the properties of the SIBS polymer (588 cells/mm2) and the properties of culture plastics (732 cells/mm2) were discovered. Cell adhesion for the ePTFE material was 212 cells/mm2. Percentage of dead cells on SIBS and ePTFE samples was 4.40 and 4.72% (p = 0.93), respectively, for culture plastic – 1.16% (p < 0.05). Cell proliferation on the ePTFE surface (0.10%) was significantly lower (p < 0.05) than for the same parameters for SIBS and culture plastic (62.04 and 44.00%). Implantation results (60 days) showed the formation of fibrous capsules with average thicknesses of 42 μm (ePTFE) and 58 μm (SIBS). Calcium content in the explanted samples was 0.39 mg/g (SIBS), 1.25 mg/g (ePTFE) and 93.79 mg/g (GA-xenopericardium) (p < 0.05). Hemolysis level of red blood cells after contact with SIBS was 0.35%, ePTFE – 0.40%, which is below positive control (p < 0.05). Maximum platelet aggregation of intact platelet-rich blood plasma was 8.60%, in contact with SIBS polymer – 18.11%, with ePTFE – 22.74%. Conclusion. In terms of hemocompatibility properties, the investigated SIBS polymer is not inferior to ePTFE and can be used as a basis for development of polymeric prosthetic heart valves.

Aim of the study was to identify the mechanism of specific endothelial toxicity related to calcium phosphate bions (CPB). Material and methods. CPB and magnesium phosphate bions (MPB) were artificially synthesised through supersaturation of culture medium with respective salts and then added to human endothelial cells (EA.hy 926) and murine endothelial cells (2H-11) to study: 1) spatiotemporal aspects of bion internalisation by means of transmission electron microscopy and confocal microscopy; 2) whether blocking of H+-ATPase by lysosomal inhibitor bafilomycin A1 affects endothelial toxicity of bions; 3) expression of caspase-3 and its substrate poly(ADP-ribose) polymerase (PARP-1). Results. CPB were internalized by endothelial cells as early as 1 h upon their addition and were localized in lysosomes; after 4 h, we detected release of calcium ions (Ca2+) from lysosomes to cytosol accompanied by multifold increase in cleaved caspase 3 and its substrate PARP-1. Bafilomycin A1 rescued endothelial cells from death induced by slightly soluble CPB regardless of exposure time and dose; however, freely soluble MPB did not evince endothelial toxicity regardless of bafilomycin A1 addition. Conclusion. Upon internalization by endothelial cells, CPB cause their death due to dissolution in lysosomes and subsequent release of calcium ions into the cytosol, ultimately leading to cleavage of executioner caspases. MPB lack endothelial toxicity because their dissolution does not lead to release of calcium ions. Therefore, specific endothelial toxicity of CPB is defined by lysosome-dependent cell death.

Aim: to assess the contribution of primary tissue failure, calcification, bacterial contamination and pannus to bioprosthetic valve dysfunction.Materials and methods. To evaluate degenerative changes of the «UniLine» bioprosthesis explanted from the mitral position with macroscopic examination, light and scanning electron microscopy, and micro-computed tomography (micro-CT). Light microscopy was used to analyze cell composition, the presence of bacteria, the localization of calcific deposits and recipient cells. Scanning electron microscopy allowed confirming the presence of bacteria. Micro-CT was used to evaluate the deformation of the bioprosthetic elements, the distribution of calcific deposits and their volume in the valve tissue.Results. The presence of pannus, calcification, primary tissue failure and bacterial contamination were found among the causes leading to bioprosthetic dysfunction. Prosthetic leaflets showed pannus growth from the inflow tract. Excessive circumferential pannus extended into outflow tract. Calcific deposits were mostly localized in the commissural zone and the central portion of the leaflets. The total volume of calcification accounted for 1/3 of the bioprosthetic tissue component. The relationship between calcification and stress-strain properties of the bioprosthetic elements has been indicated. The asymmetric deformation of the bioprosthetic stent frame and leaflets with 1.5-fold thickening of the last has been found. The areas with loose and fragmented collagen and elastic fibers contained red blood cells and neutrophils. Endothelial cells and fibroblastic cells were present in the outer surface layers. There were no signs of calcification in the areas accumulating cells and bacteria.Conclusion. We can assume that primary tissue failure, calcification, bacterial contamination and pannus independently contribute to the onset of bioprosthetic heart valve dysfunction.

Tissue engineering is a promising area for the production of small-diameter vascular grafts. In recent years, a number of strategies have been developed to make the polymer surfaces of vascular prostheses capable to selectively adhesion of endothelial cells. The arginine–glycine–aspartic acid (RGD) sequence (a cell adhesion site that is present on many extracellular matrix proteins) is the promising target for modification. The efficiency of attachment of endothelial cells can be influenced both by the structure of RGD peptide and the extent of linker group.Aim: to determine the optimal method for modification of non-woven matrices of polyhydroxybutyrate/ valerate and polycaprolactone (PHBV/PCL) by RGD-peptides leading to the increasing of adhesion, viability and proliferation of endothelial cells.Materials and methods. Electrospinning was used to produce 4 mm diameter tubular polymer matrices from PHBV/PCL. Modification of surface of polymer scaffolds was performed using 4,7,10-trioxa-1,13-tridekandiamin, hexamethylenediamine, glutaraldehyde, ninhydrin, ascorbic acid, a cyclic peptide c [RGDFK], RGDK, AhRGD. The quality of modification was assessed by ninhydrin test and determination of arginine-containing peptide. The structure of the surface of matrices before and after modification was studied by scanning electron microscopy. Adhesion, viability and proliferation of Human umbilical vein (HUVEC) endothelial cells cultured for 7 days on the surface of matrices in the presence of RGD and without one were examined using fluorescence and laser scanning microscopy after the cells were pre-stained with fluorescent nuclear dyes (ethidium bromide and Hoechst 33342), and also by special kits for proliferation assessment (Click-iTTM Plus EdU Alexa FluorTM 488 Imaging Kit).Results. RGD peptides bound to the matrix surface via a long linker (4,7,10-trioxa-1,13-tridecanediamine) were characterized by the increased bioavailability and activity. High level of cell adhesion, viability and proliferation were noted on the surface of RGDK and c[RGDFK] modified matrices, whereas their paired analogues with a short linker (hexamethylenediamine) showed low results of cellular viability even against satisfactory cell adhesion.Discussion. Non-woven matrices based on PHBV/PCL and modified using 4,7,10-trioxa-1,13-tridecanediamine showed better results in case of adhesion of HUVEC and subsequent preservation of cell viability and proliferation. RGD-containing peptides of RGDK and c [RGDFK] were more tropic to endothelial cell receptors.

The literature review discusses the studies on developing the polymer membrane of a coronary stent graft. The new generation of coronary stent grafts is designed to increase the hemocompatibility and ensure its delivery to poorly accessible artery regions. Based on the clinical use results, three groups of promising polymers were identified: biostable polyurethanes, polyvinyl alcohol-based cryogels, bioresorbable compositions based on polylactide-caprolactone and lactic acid-glycolic acid copolymer. However, the possibility of their clinical application requires further experimental studying.

Aim. To study relationship between the polymorphism of five polymorphic sites of EDN1, SELE, SELP, SELPLG genes with the risk of infectious endocarditis (IE) and the connection of genotypes of studied sites with concentration of the corresponding proteins in the blood.Material and methods. The study included 208 patients with IE and 300 healthy donors. Genotyping was performed on 6 polymorphic sites of 4 genes by real-time PCR. The levels of endothelin-1, sE-selectin, sP-selectin were determined by the ELISA technique. Results. We determined that the T allele (G/T genotype) of rs5370 polymorphic site of EDN1 gene have a risk effect on IE in the superdominant mode of inheritance (OR=1,58, 95% CI=1,05-2,35, p=0,027). At the same time, the association between levels of endothelin-1, sE and sP selectins and carriage of the variable genotypes of the corresponding genes was not found. We noted that serum concentrations of biologically active endothelial proteins differ between patients with IE and healthy individuals. Conclusion. The study confirms the presence of endothelial dysfunction markers in the blood of patients with IE. It shows the association between rs5370 site of EDN1 gene and an increased risk of IE in heterozygous carriers of the minor T allele. However, additional research is needed to confirm these observations and to get detailed description of how gene variability determines underlying risk for IE.

Aim. To assess the contribution of pannus and calcification to the development of bioprosthetic valve dysfunction after tricuspid valve replacement in a pediatric patient.Materials and methods. A 3-month-old patient presented with tricuspid valve dysplasia and grade 4 tricuspid insufficiency underwent tricuspid valve replacement with the bioprosthesis «PeriCor» (ZAO «NeoKor», Russian Federation). The patient at the age of 6 years required a redo tricuspid valve replacement 5 years 8 months after initial surgery. Degenerative changes of the dysfunctional bioprosthetic valve explanted from the tricuspid position were assessed using macroscopic description and light microscopy. Cellular composition, the presence of bacteria, colocalization of calcifications with recipient cells were analyzed. The distribution of calcifications and their volume in the biomaterial tissue were estimated using microcomputer tomography imaging (micro-CT).Results. Bioprosthetic valve dysfunction was mainly caused by the pannus formation which was shown to encapsulate the anterior leaflet, resulting in its total failure and severe stenosis (reduced effective orifice area). There were no signs of ruptures and perforations in the valve tissues found. All leaflets were shown to contain predominantly fibroblastic cells and single blood cells, mainly located in the surface layers of the leaflets in the regions without any signs of calcification. Bacteria staining was negative for all types of the studied biomaterials. Calcifications were present in all xeno-tissue elements of the explanted bioprosthesis (i.e. leaflets, aortic segment, and pericardium). In addition, calcifications were also found in pannus growing during a functioning bioprosthetic valve. Calcifications were predominantly located in the co-optation and commissure zones of the leaflets. Importantly, massive calcifications were observed around the bioprosthetic stent frame. The total volume of calcification accounted for 1/3 of the biological component of the bioprosthesis (729 mm3).Conclusion. According to the data obtained in this study, we may conclude that the primary cause of the bioprosthesis failure was the growth of connective tissues, resulting in pannus-related dysfunction, rather than severe calcification of all bioprosthetic components. One may assume that bioprosthetic dysfunction is related to the peculiarity of the inflammatory response of the preschool patient. However, this typeof dysfunctions requires further investigation.

Aim. To evaluate specificity of endothelial toxicity of calcium-phosphate bions (CPB) in vivo.Material and methods. Toxicity of calcium-phosphate bions and magnesiumphosphate bions (MPB) in relation to intima of abdominal aorta of the Wistar rats, was assessed by single intravenous injection after balloon angioplastics with further explanting of aortas in five weeks. Bioptates were analyzed: 1) with classical histological methods (hematoxilin-eosine, alizarin red, van Gison, Russell-Movat) with light microscopy; 2) immune fluorescence coloring of cryoslices (combinational coloring for marker of mature endothelial cells CD31 and marker of progenitory CD34, for CD31 and marker of vascular smooth muscle cells α-smoothmuscle actin (α-SMA), for vimentin and α-SMA, for extracellular matrix marker collagen type IV and α-SMA, after all colorings there was additional nuclear 4’,6-diamidine-2-phenylindol color) with further confocal microscopy. In all animals the blood was collected with serum extraction for systemic inflammation molecules analysis, as chemoattractant protein (МСР-1/CCL2) and ceruloplasmin via the immune enzyme analysis.Results. With the difference from CPB, MPB did not lead to intimal hypertrophy in abdominal aorta in rats. Shaping of neointima in aorta is related with CPB-induced endothelium damage that induces a phenotype shift in mesenchymal cells (smooth muscle cells and fibroblasts) from contractile (for smooth muscle) and non-active (for fibroblasts) towards synthetizing.Conclusion. Intravenous load of MPB did not lead to intimal hypertrophy that witness on specificity of endothelial toxicity of CPB, with phenotypical shift of the mesenchymal cells in neointima.

The aim of the study was to perform a series of in vitro tests of a prototype of the developing heart valve prosthesis to evaluate its functional characteristics. Materials and methods. In this work we have used the frames and full prototypes of the prosthesis, consisting of a stent-like stainless steel support frame with mounted biological leaflets and cover. The authors evaluated the calculated and experimental forces necessary for the displacement of the sutureless implanted prosthesis using the test machine under uniaxial tension. The risk of defects and damages to the supporting framework as a result of implantation was evaluated by scanning electron microscopy. The hydrodynamic characteristics of the prosthesis were investigated under physiological conditions and «valvein-valve» implantation. Evaluation of the ergonomics and applicability of the proposed construction on the cadaver heart model of cattle was carried out. Results. As a result of the forces assessment, it was found that the force required to shear the prosthesis was 3.12 ± 0.37 N, while the calculated value was 1.7 N, which is significantly lower than the obtained value. The comparison of the images obtained with small and large magnifications demonstrated the absence of critical surface defects. Additional analysis under the super-large magnifications also did not reveal problem areas. During the hydrodynamic study, it was shown that the average transplant gradient increased slightly from 2.8–3.4 to 3.2–4.5 mm Hg for the initial prosthesis and the «valve-in-valve» complex, respectively. The decrease of the effective orifice area was 6–9% relative to the initial one. Evaluation of the implantation technique demonstrated the consistency of the approach: the use of the developed holder in combination with the balloon implantation system made it possible to position the prosthesis throughout the procedure. Conclusion. The series of tests demonstrates the consistency of the developed design, intended for the replacement of a failed prosthetic valve of the heart with the «valve-in-valve» implantation.

Recently, the number of cardiac surgery in the world and particularly in Russia is raising, especially with utilization of biological prostheses; it is related to average population ageing too. Main disadvantage of such devices is restricted time period of work due to degrading of biomaterials, which demands additional surgery in longterm period (5-10 years). The technology of alternative reimplantation of bioprosthesis by method “prosthesis-into-prosthesis” using transcatheter low invasive devices is the most promising solution for the mortality risk reduction from operations on replacement of failing prosthesis. Current review includes an analysis of clinical results of application of that methodology for correction of acquired defects of aortic, mitral, tricuspid valves, and pulmonary artery valve. The results that are described, witness increasing interest of the world society in methodic as “prosthesis-into-prosthesis”, presenting via attempts for systematization and structuring of the interventions results. However complications that occur, risk and procedure restrictions significantly slow wider spread of the method application.

Biodegradation rate and tensile strength are essential for membranes, applied to prevent post-surgical adhesion formation. The study is aimed at evaluating biodegradation rate, physical and mechanical properties of the membranes made from biodegradable polymer composites in vitro, namely polyhydroxybutyrate / oxovalerate (PGBV), polylactide (PLA), and polylactide-co-glycolide (PLGA). PLGA copolymers, having a polylactide: glycolide ratio in the proportion of 70:30 and 60:40, reported the highest biodegradation rate, moreover, the addition of PGBV to this polymer composite may increase the bioresorption rate of the latter by1.2 – 1.3 times. Thus, the physical and mechanical testing findings have shown that the addition of PLGA to PGBV results in improved properties of the studied samples – PLGA added to the polymer composite in the proportion 60:40 increased its strength by 27.5 %, and its elastic properties by 70 % compared to PGBV. The obtained results demonstrated that the adjustment of the bioresorbable polymer formulation for anti-adhesive membranes may regulate biodegradation rate, physical and mechanical properties.

Suture material has significant influence on remote results of surgical intervention, and in particular, in reconstructive operations on heart and vessels. Despite the great choice of suture material in the market, there are no threads with directed antithrombotic effect. With the purpose of increasing thromboresistant properties of suture material, the most promising method is the application of biodegradable coating based on polyhydroxyalkanoate biopolymer and nonfractionated heparin by the method of chemical grafting. Antithrombotic coating of polypropylene thread is achieved through the creation of reactive intermediate layer. The study of grafting of heparin onto substrate by the methods of diffuse reflectance infrared spectroscopy and scanning electron microscopy showed uniform location and strong holding of heparin on the surface of the thread.

The aim of the study was to evaluate the efficacy of lecithin/cholesterol liposomes in the therapy of experimental venous congestion-induced chronic liver insufficiency. The effects of the empty liposomes, ATP and phosphocreatine-containing liposomes and alpha-tocopherol and superoxide dismutase-containing liposomes were studied. It was found that liposomal drugs have a hepatoprotective effect, i.e. they decrease blood enzyme activity (cytolysis markers), reduce oxidative stress and preserve histologic integrity of the liver.

Designing a hybrid vascular graft using biocompatible and biodegradable polymers is one of the ways to fill the market with vascular grafts of a small diameter necessary for coronary artery bypass surgery. Good adhesive properties of cultivated cells and low cytotoxicity of biopolymers can improve biocompatibility of polymer-based vascular grafts. The impact of protein modification of membranous polyhydroxyalkanoate and polycaprolactone scaffolds surface on their adhesive properties and cytotoxicity to multipotent mesenchimal stromal cells was evaluated. We used the following compositions of membranous scaffolds: № 1 polyhydroxybutyrate valerate ММ 2 307 kDa with polycaprolactone ММ 80 000 kDa, № 2 had the same composition but was made using a magnetic stirrer, №3 polyhydroxybutyrate ММ 541 kDa with polycaprolactone ММ 80 000 kDa and № 4 polycaprolactone ММ 80 000 kDa only. Premodification of scaffolds surfaces with 75, 50 and 25% fetal calf serum was found to significantly reduce cytotoxicity of scaffold № 4 and improve the adhesive properties of scaffolds № 1, 2 and 3. Premodification with fibronectin (10 µg/ml) mostly improved the adhesive properties of scaffolds № 1—4.

The absence of reliably functioning small-diameter vascular grafts for coronary artery bypass graft surgery remains one of the most important issues of cardiovascular surgery. Tissue-engineered grafts have to be characterized by highly hemocompatible, biomechanical and biocompatible properties, be quickly biodegradable and have non-toxic degradation products. This article presents polyhydroxyalkanoate and policaprolactone main characteristics and evaluates their potential use as polymers for producing vascular grafts. Biocompatibility, good physical and mechanical properties of these polymers and their better performance in copolymer scaffolds were demonstrated.