Preparation of heparinized acellular vascular scaffold and hemocompatibility evaluation / 中国组织工程研究

BACKGROUND:Acellular vascular scaffolds can mimic the microstructure and function of native blood vessels,but some extracellular matrix loss occurs during their preparation,which affects their hemocompatibility.Therefore,it is necessary to modify them to improve their hemocompatibility. OBJECTIVE:To assess the hemocompatibility of acellular vascular scaffold prepared by Triton-x100/heparin sodium treatment. METHODS:The abdominal aorta was taken from SD rats and randomly divided into control and experimental groups.The control group was treated with Triton-x100 for 48 hours.The experimental group was treated with Triton-x100 for 48 hours and then treated with heparin sodium.The morphology and hydrophilicity of the two groups of acellular vascular scaffolds were detected.The hemocompatibility of the two groups of acellular vascular scaffold was evaluated by recalcification coagulation time test,platelet adhesion test,dynamic coagulation time test,hemolysis test,and complement activation test. RESULTS AND CONCLUSION:(1)Scanning electron microscopy showed that the surface of the two groups of vascular scaffolds was relatively intact,and a large number of fiber filaments appeared on the surface of the scaffolds after decellularity treatment,and the surface microstructure changed significantly.The water contact angle of the two groups of vascular scaffolds was smaller than that of natural vessels(P<0.000 1).There was no significant difference in water contact angle between the two groups(P>0.05).(2)The coagulation time of vascular scaffold was longer in the experimental group than in the control group(P<0.05).The number of platelets attached to the scaffold membrane was less in the experimental group than that in the control group(P<0.000 1).The coagulation index was greater in the experimental group than that in the control group(P<0.01),and the complement level was lower in the experimental group than that in the control group(P<0.001).The hemolysis rate of the two groups was lower than 5%of the national standard.(3)To conclude,acellular scaffold treated with Triton-x100/heparin sodium has excellent hemocompatibility.

Hemocompatibility of bioprosthetic heart valve materials respectively based on glutaraldehyde and non-glutaraldehyde treatment / 中国胸心血管外科临床杂志

@#Objective    To study the hemocompatibility of bioprosthetic heart valve materials respectively based on glutaraldehyde and non-glutaraldehyde treatment. Methods    Fresh bovine pericardium was treated with glutaraldehyde or non-glutaraldehyde after adipose tissue was removed. To evaluate the hemocompatibility of the two bioprosthetic heart valve materials, hemolysis test, in vitro fibrinogen adsorption experiment, platelet adhesion experiment, thrombin-antithrombin complex (TAT) test, complement activation assay and ex vivo circulation experiment were performed. Results    The hemolysis test results demonstrated that both of the materials showed hemolytic rates lower than 5%. The results of TAT test and complement activation assay showed no statistical differences among the two materials and the blank control group. Compared to the bioprosthetic heart valve materials with glutaraldehyde-based treatment, the materials with non-glutaraldehyde-based treatment showed significantly decreased fibrinogen adsorption, platelet adhesion and thrombosis. Conclusion    Compared to the bioprosthetic heart valve materials with glutaraldehyde-based treatment, the materials with non-glutaraldehyde-based treatment show better hemocompatibility.

Structural control and characterization of hierarchically structured fibrous scaffolds / 中国修复重建外科杂志

Objective: To prepare hierarchically structured fibrous scaffolds with different morphologies, and to explore the additional dimensionality for tuning the physicochemical properties of the scaffolds and the effect of their hemocompatibility and cytocompatibility. Methods: Electrospinning poly (e-caprolactone) (PCL)/polyvinylpyrrolidone (PVP) bicomponent fibers (PCL∶PVP mass ratios were 8∶2 and 5∶5 respectively), and the surface porous fibrous scaffolds were prepared by extracting PVP components. The scaffolds were labeled PCL-P8 and PCL-P5 respectively according to the mass ratio of polymer. In addition, shish-kebab (SK) structured scaffolds with different kebab sizes were created by solution incubation method, which use electrospun PCL fibers as shish while PCL chains in solution crystallizes on the fiber surface. The PCL fibrous scaffolds with smooth surface was established as control group. The hierarchically structured fibrous scaffolds were characterized by field emission scanning electron microspore, water contact angle tests, and differential scanning calorimeter (DSC) experiments. The venous blood of New Zealand white rabbits was taken and hemolysis and coagulation tests were used to characterize the blood compatibility of the scaffolds. The proliferation of the pig iliac artery endothelial cell (PIEC) on the scaffolds was detected by cell counting kit 8 (CCK-8) method, and the biocompatibility of the scaffolds was evaluated. Results: Field emission scanning electron microscopy showed that porous morphology appeared on the surface of PCL/PVP bicomponent fibers after extracting PVP. In addition, SK structure with periodic arrangement was successfully prepared by solution induction, and the longer the crystallization time, the larger the lamellar size and periodic distance. The contact angle and DSC measurements showed that when compared with smooth PCL fiber scaffolds, the crystallinity of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds increased, while the hydrophobicity of PCL-SK fibrous scaffolds increased, but the hydrophobicity of PCL porous scaffolds did not change significantly. The hemolysis test showed that the hemolysis rate of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds was higher than that of PCL fibrous scaffolds. According to American Society of Materials and Tests (ASTM) F756-08 standard, all scaffolds were non-hemolytic materials and were suitable for blood contact materials. Coagulation test showed that the coagulation index of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds was higher than that of PCL fibrous scaffolds at 5 and 10 minutes of culture. CCK-8 assay showed that both hierarchically structured fibrous scaffolds were more conducive to PIEC proliferation than PCL fibrous scaffold. Conclusion: Based on electrospinning technology, solution-induced and blend phase separation methods can be used to construct multi-scale fiber scaffolds with different morphologies, which can not only regulate the surface physicochemical properties of the scaffolds, but also have good blood compatibility and biocompatibility. The hierarchically structured fibrous scaffolds have high application potential in the field of tissue engineering.

Bioactividad y pruebas de hemólisis de compósitos de hidroxiapatita zirconia (HAp/ZrO2-8Y2O3) para implantes óseos / Bioactivity and hemolysis test of hydroxyapatite/zirconia composites (HAp/ZrO2-8Y2O3) for bone implants

Resumen Se presenta la síntesis de compósitos de hidroxiapatita/zirconia (HAp/ZrO2-8Y2O3) por el método de mezclado líquido en base al método de Pechini, cuya innovación radica en la obtención simultánea de ambas fases con distribución uniforme, aunque tiene la limitante de la interacción de los cationes, propiciando la formación de fases secundarias si no se controlan las variables. Los materiales fueron conformados en discos de 1 cm de diámetro y tratados a 1400 °C, para caracterizarse por espectrometría de infrarrojo (FTIR-ATR) y difracción de rayos X (DRX). Las pruebas de bioactividad fueron realizadas mediante el método de inmersión en fluidos fisiológicos simulados durante 21 días y caracterizadas por microscopia electrónica de barrido (MEB) y espectrometría de fotoelectrones emitidos por rayos X (XPS). Las pruebas de hemólisis se basaron en la norma ASTM F 756-00. Después de la inmersión, se observó la presencia de cristales de hidroxiapatita sobre la superficie del compósito, además los análisis de XPS muestran señales de energía para los elementos de calcio y fósforo. En cuanto a las pruebas de hemólisis se observaron grados de citotoxicidad por debajo del 3% con lo cual se infiere que son hemocompatibles, aunque se requieren más estudios de biocompatibilidad para su aplicación biomédica.

Abstract The synthesis of hydroxyapatite/zirconia composites (HAp/ZrO2-8Y2O3) is presented, using the liquid mixing method based on the Pechini method, whose innovation lies in the simultaneous synthesis of both phases with uniform distribution, although it has the limitation of the cations interactions, favoring the formation of secondary phases if the variables are not controlled. The obtained materials were formed into discs of 1 cm in diameter and treated at 1400 °C, and then characterized by infrared spectrometry (FTIR-ATR) and X-ray diffraction (XRD). The bioactivity tests were carried by the immersion method in simulated body fluid for 21 days and characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectrometry (XPS). The hemolysis tests were based on the ASTM F 756-00 standard. After the immersion, the presence of hydroxyapatite crystals on the surface of the composite was observed; in addition, the XPS analyzes show energy signals for the elements of calcium and phosphorus. Regarding the hemolysis tests, degrees of cytotoxicity were observed below 3%, it is inferred that they are hemocompatible, although more biocompatibility studies are required for biomedical application.

Análisis espectroscópico y morfológico de una válvula artificial para el corazón / Spectroscopic and morphologic analisis of an artificial cardiac valve

RESUMEN Los materiales que están en contacto con el sistema corporal requieren de la característica primordial que les permita su aceptación e integración en el organismo: la biocompatibilidad. De igual manera, deben exhibir excelentes propiedades mecánicas, tribológicas y topográficas para que su prestación del servicio en el tejido especificado sea el más óptimo, pudiendo esbozar estas características mediante la caracterización de estos materiales a través de técnicas espectroscópicas y microscópicas. En el presente trabajo, una válvula artificial para el corazón fabricada en titanio y recubierta con diamond-like carbon (DLC), material altamente biocompatible, fue sometida a análisis XPS, FTIR y morfológico. En estos se encontró una alta interdifusión del recubrimiento con el sustrato junto con una gran señal de enlaces sp3. Los enlaces terminales CH3 suponen una película poco compacta. La rugosidad del recubrimiento fue baja y adecuada para fines hemocompatibles.

ABSTRACT The materials that are in contact with the body system require the fundamental characteristic that allows their acceptance and integration in the organism, the biocompatibility. Likewise, they must show excellent mechanical, tribological and morphological properties, so that their provision of a service in the specific tissue is the most optimal, being able to sketch such characteristics through the characterization of these materials by spectroscopic and microscopic techniques. In this work, an artificial valve for the heart made of titanium and coated with diamond-like carbon (DLC), highly biocompatible material, was subjected to XPS, FTIR, and morphological analysis. A high interdiffusion of the coating and the substrate was found, together with a large signal of sp3 bonds. The CH3 terminal bonds represent a little compact film. The film roughness of the coating was low and adequate for hemocompatible purposes.

In vivo assessment of hemocompatibility of a ventricular assist device in healthy swine / Evaluación de la hemocompatibilidad in vivo (cerdos sanos) de un dispositivo de asistencia ventricular

Objective: To assess the hemocompatible performance of a novel implantable pneumatic ventricular assist device (VAD, Innovamédica, México) in healthy swine. The aim of this pilot study was first, to determine if short-term VAD implantation elicited a remarkable inflammatory response above that expected from surgical trauma; and second, to assess if heparinized or passivated VAD coatings, in combination with systemic anticoagulant or antiaggregant therapies, modified the VAD's hemocompatible performance. Methods: Hemodynamic, physiologic, inflammatory and histological parameters were measured in 27 pigs receiving VAD support for six hours, testing combinations of heparinized or passivated VAD coatings and systemic anticoagulant/ antiaggregant therapies. Mean concentrations of interleukin-1 β (IL-16), interleukin-6 (IL-6), C-reactive protein (CRP), or thrombin-antithrombin III (TAT) complexes (coagulation indicator) were measured from blood. ANOVA statistics were employed. Results: No substantial increases in mean IL-1β, IL-6, CRP, or TAT were obtained during VAD support. Hemodynamic and physiologic parameters were normal. We found no evidence of thromboembolisms or micro-infarctions in heart and lung samples. No major coaguli/deposits were found in VAD compartments. Overall, no remarkable differences in measurements were found using heparinized, passivated, or uncoated VAD, or with systemic anticoagulation, antiaggregant therapy, or no treatment. Conclusions: Our findings demonstrate, firstly, that during the time-period tested, the VAD elicited negligible inflammation above the effects of surgical trauma; and secondly, that little coagulation was observed upon VAD support in any of the cases tested. Contemplating further validation studies, our data indicate that the Innovamédica VAD is a highly hemocompatible system.

Objetivo: Evaluar la hemocompatibilidad de un nuevo dispositivo de asistencia ventricular (DAV, Innovamédica, México) neumático e implantable, en cerdos sanos. En este estudio piloto se propuso determinar primero, si la implantación a corto plazo del DAV suscitaría una respuesta inflamatoria por encima de aquella esperada tras trauma quirúrgico; segundo, evaluar si recubrimientos heparinizados o pasivos del DAV, en combinación con tratamientos sistémicos anticoagulantes o antiplaquetarios, modificarían la hemocompatibilidad del DAV. Métodos: Se midieron parámetros hemodinámicos, fisiológicos, inflamatorios e histológicos en 27 cerdos recibiendo soporte del DAV durante seis horas, evaluando combinaciones de recubrimientos heparinizados y pasivos del DAV, y terapias sistémicas anticoagulantes / antiplaquetarias. Se obtuvieron, a partir de sangre, las concentraciones promedio de interleucina-1 (IL-1β), interleucina-6 (IL-6), proteína C reactiva (PCR) y los complejos trombina-antitrombina III (TAT) (índice de coagulación). Se emplearon análisis estadísticos ANOVA. Resultados: No se observaron incrementos importantes en los niveles promedio de IL-1β, IL-6, PCR, o TAT durante soporte del DAV. Los parámetros hemodinámicos y fisiológicos fueron normales. No existió evidencia alguna de trom-boembolias o micro-infartos en muestras de miocardio y pulmón. No se encontraron coágulos o depósitos mayores en compartimentos del DAV. En general, no se apreciaron diferencias notables de mediciones utilizando dispositivos con recubrimiento heparinizado, pasivo o sin recubrimiento, en conjunto con terapia sistémica anticoagulante, antiplaquetaria o sin ella. Conclusiones: Nuestros hallazgos demuestran, primero, que durante el periodo de medición experimental, el DAV suscitó una respuesta inflamatoria mínima por encima de los efectos de trauma quirúrgico, y; segundo, en todos los casos evaluados, se observaron escasos o inexistentes efectos de coagulación durante soporte ventricular. Contemplando estudios adicionales de validación, nuestros datos indican que el DAV Innovamédica es un sistema altamente hemocompatible.

Evaluation of hemocompatibility of a new biopolymer material for bioabsorbable stents used for children with vascular stenosis in vitro / 临床儿科杂志

Objective To evaluate the hemocompatibility of polydioxanone(PDO)bioabsorbable stents.Methods Whole blood clotting time,prothrombin time(PT),activated partial thromboplastin time(APTT),platelet adhesion and hemolysis were used to evaluate the hemocompatibility of PDO bioabsorbable stents,and the results were compared with those of 316L stainless stents which are widely used clinically.Results The anticoagulant property of PDO bioabsorbable stents was similar to that of 316L stainless stents.Both PDO bioabsorbable and 316L stainless stents were not prone to activate blood coagulation factors.Compared with 316L stainless stents,PDO bioabsorbable stents had weaker platelet adhesion and activation.Hemolysis ratios of two groups were less than 5%.Conclusions PDO bioabsorbable stents had good hemocompatibility in vitro.

Experimental study on hemocompatibility of domestic silicone-covered stent / 介入放射学杂志

Objective To evaluate the hemocompatibility of domestic silicone-covered stent in the iliac arteries of canine model. Methods Eighteen domestic stents were placed in ililac arteries of 9 adult dogs after larger ballon PTA, which included 10 silicone-covered stents and 8 bare stents for control. DSA was performed at 1,4,12 weeks after stent implantation in the iliac arteries of two groups to observe the outcomes of patency or restenosis. Animals were then euthanized isolating and stainning the stented arteries with hematoxylin and eosin for histological examination. Finally, the acute thrombosis, reendothelialization and the neointimal proliferation of both covered and bare stents were quantified on histological cross-section. Results All bare stents were patent in 12 weeks, but two silicone-covered stents were occluded at 4,12 week respectively (patent rate was 80%). Stented vascular stenosis rate was averaging 72.3% at 12 week in covered stents and 36.7% in bare stents. Conclusions The hemocompatibility of silicone-covered stents is not better than that of bare stents. Silicone appear to be inert in this experimental application.