肝素涂层体外循环管道的制备及生物学性能评价

通过离子键方式将肝素分子结合于体外循环医用聚氯乙烯管道中 ,进行了体外转流抗凝血性能测定和细胞毒性、肌肉植入等生物学性能评价 ,结果显示肝素分子结合于聚氯乙烯材料表面 ,同时筛选出具有抗凝血活性和良好生物相容性的聚乙烯亚胺 肝素涂层方法。     

体外循环聚氯乙烯管路地塞米松涂层的性能

背景：将地塞米松以某种涂层方式固定到体外循环管道表面,既可持续地起到抗炎作用,又不至于由于血药浓度过大而产生不良反应,最大限度地发挥地塞米松的抗炎作用。 目的：研制新型抗凝血活性的地塞米松磷酸钠涂层管路,评价涂层管道稳定性、抗凝活性及抗血小板等性能。 方法：用浓硫酸、聚乙烯亚胺依次预处理聚氯乙烯体外循环管路表面。分别通过预混、离子键两种方式制备地塞米松磷酸钠涂层聚氯乙烯体外循环管道,对涂层管道进行涂层物定量分析,以未涂层的聚氯乙烯体外循环管路为空白对照,评价3组抗凝血、抗血小板、抗蛋白黏附等性能及涂层聚氯乙烯体外循环管道的体外释放特性。 结果与结论：预混及离子键制备的地塞米松磷酸钠涂层聚氯乙烯管道表面固定地塞米松磷酸钠的最大固定量分别为(2.06±0.68),(3.33±0.75) μg/cm²。预混制备的地塞米松磷酸钠涂层聚氯乙烯管道抗凝血、抗血小板及蛋白黏附效果优于离子键制备的地塞米松磷酸钠涂层聚氯乙烯管道和空白对照组(P < 0.05),且体外释放效果优于离子键制备的地塞米松磷酸钠涂层聚氯乙烯管道。表明通过预混方式制备的地塞米松磷酸钠涂层缓释及抗凝性能良好,有抗血小板黏附及血栓形成的功能,能满足体外循环中短期转流的要求。     

MTT法评价肝素涂层医用聚氯乙稀的细胞毒性

目的　评测 3种肝素涂层医用聚氯乙稀材料的细胞毒性。方法　采用肝素氯烃基二甲基代苯甲胺复合物(HBC)、肝素苯扎溴胺复合物 (HBB)和肝素聚乙烯亚胺复合物 (HPEI) 3种方法对医用聚氯乙稀材料进行肝素涂层 ;根据国家标准提取各种材料的浸提液 ;通过体外细胞培养 ,四唑盐 (MTT)比色法评价各种涂层材料的细胞毒性。结果　HBC和HBB方法涂层的医用聚氯乙稀材料具有较低的光吸收 (OD)值 ,而HPEI方法涂层的医用聚氯乙稀材料OD值高于其它 2组 (P <0 .0 1) ,并随时间延长呈上升趋势。结论　HBC和HBB 2种方法涂层的医用聚氯乙稀材料具有较强的细胞毒性 ,而HPEI方法处理的聚氯乙稀材料细胞相容性好 ,具有进一步应用前景     

海藻酸钠交联肝素涂层在体外循环及人工心肺支持装置管路中的应用

背景：目前国内体外循环心脏手术使用的非肝素涂层管路和插管对血液破坏大、炎性反应重,影响心脏手术后患者的恢复和生存。 目的：采用生物医用高分子材料研制新型体外循环管道肝素涂层技术,并对其稳定性及抗凝血性能进行研究。 方法：利用CaCl₂将活化医用聚氯乙烯体外循环管道内表面修饰形成Ca2+膜,并与海藻酸钠和肝素交联;其中Ca²⁺与海藻酸钠、肝素钠中的Na+反应,从而使线型聚合物分子发生交联,形成化学交联海藻酸钠-肝素复合物的网状结构,实现生物型材料肝素化涂层。 结果与结论：CaCl₂修饰活化医用聚氯乙烯体外循环管道并与海藻酸钠和肝素交联反应,形成生物型高分子材料肝素化涂层管道,试验证明肝素化涂层管道具有良好的血液相容性、稳定性、抗凝血性能,可满足体外循环中短期转流的要求。     

肝素涂层医用聚氯乙烯的细胞毒性研究

本研究通过肝素—氯烃基二甲基代苯甲胺复合物(A组)、肝素—苯扎溴胺复合物(B组)和肝素—聚乙烯亚胺复合物对医用聚氯乙烯体外循环管道进行了肝素涂层,同时采用材料直接接触细胞培养法和四唑盐(MTT)比色试验评价各种涂层材料的细胞毒性。结果显示A、B组材料直接接触L-929细胞后24h即引起细胞大量死亡,而C组材料直接接触后具有良好的细胞相容性。MTT比色试验也表明A、B两种涂层材料具有较低的OD值。A、B两种涂层材料具有较强的细胞毒性,而C方法处理的聚氯乙烯材料不引起细胞死亡,具有进一步临床应用前景。     

共价-离子结合肝素改性对牛心包膜抗凝血性能的影响

目的在碳化二亚胺交联的去细胞牛心包膜上采用3种方式进行肝素改性,即共价键合肝素、离子结合肝素以及共价-离子联合负载肝素,比较这3种肝素化方式对牛心包膜抗凝血性能的影响,并筛选出最佳肝素化方式。方法通过溶血试验、血小板黏附实验、体外凝血测试以及复钙时间测定观察3种方式肝素化的基质抗凝血性能和血栓形成情况,以评价其血液相容性。结果综合上述4项检测的结果,共价-离子联合负载肝素改性的抗凝血性能优于共价键合肝素、离子结合肝素这2种单独负载肝素方式,溶血率〈5％,电镜照片无血小板黏附,体外生理盐水浸泡15d后,仍保持良好的抗凝血活性。结论共价-离子联合负载肝素,将离子结合肝素活性好、共价键合肝素稳定性强的优点结合起来,取长补短,使这种方式肝素改性的牛心包具有良好的血液相容性。     

新型多醛基海藻酸钠-肝素复合涂层的制备和筛选

背景：前期实验证明多醛基海藻酸钠-肝素复合涂层具有良好生物相容性和血液相容性,但对于最优制备条件和最优模式尚不清楚。 目的：研制一种新型多醛基氧化海藻酸钠-肝素复合涂层,筛选新型涂层制备的最佳条件。 方法：以正交实验筛选氧化海藻酸钠(或肝素)最优涂层条件,获得3种氧化海藻酸钠/肝素复合涂层模式,将复合涂层通过共价交联的方式固定到氨基化预处理/化学修饰的聚氯乙烯管道表面,从涂层物定量、蛋白黏附实验和表面接触角实验3个方面筛选最优复合涂层模式,并检测最优复合涂层的抗凝血性能。 结果与结论：氧化海藻酸钠涂层物最优涂层条件为50%浓硫酸、0.05%聚乙烯亚胺、反应溶液pH值3.5、反应温度为40 ℃和氧化海藻酸钠质量浓度为2 g/L。肝素涂层物最优涂层条件为70%浓硫酸、0.1%聚乙烯亚胺、反应溶液pH值3.5、反应温度为30 ℃和肝素质量浓度为0.1 g/L。复合涂层物最佳涂层模式氧化海藻酸钠、肝素涂层量分别为(4.07±1.35),(2.13±0.24) μg/cm²,此复合涂层具有良好的生物相容性及抗凝血性能。     

新型醛基化海藻酸钠-肝素复合涂层的制备及性能评价

研制一种新型基于多醛基海藻酸钠和肝素的复合涂层,并就其生物相容性和血液相容性进行实验和评价.通过高碘酸钠氧化海藻酸及重氮化处理肝素获得多糖分子片段,多糖分子片段通过共价交联固定于体外循环管路表面.通过红外及紫外扫描对固定的多糖分子片段进行定性及定量分析;通过血小板粘附实验及蛋白粘附实验对涂层管道的血液相容性进行评价;通过表面接触角实验评价涂层管路的亲水活性;通过凝血功能检测评价管路表面的抗凝血活性.结果显示:氧化海藻酸及重氮化处理后肝素在在管道表面固定确实;涂层组与未涂层组相比,血小板粘附量及血栓形成量均显著减少(P＜0.05);肝素涂层组(LMNH)组与空白对照(C)组相比,蛋白粘附量无显著差异(P＞0.05);海藻酸钠涂层(OSA)组、双涂层(OSA.LMNH)组与LMNH组相比,蛋白粘附量均显著减少(P ＜0.05);LMNH组、OSA.LMNH组APTT及TT时间均显著延长(P＜0.05),抗凝血性能优良;OSA组与C组相比,APTT时间显著延长(P＜0.05)具有一定的抗凝血性能;OSA组、OSA.LMNH组与C组相比,表面接触角明显减小(P ＜0.05);LMNH组与C组相比,表面接触角无显著差异(P＞0.05).实验结果表明,OSA涂层物具有更优的亲水性和抗蛋白粘附性,LMNH涂层物具有更优的抗凝血性能,多糖片段复合涂层综合了单涂层的优点,生物相容性和血液相容性较单涂层均明显改善.     

新型醛基化海藻酸钠抗凝血涂层物制备及性能评价

应用醛基化海藻酸钠交联涂层体外循环管路,并对涂层管路的血液相容性和生物相容性等性能进行研究和评价。将多醛基的氧化海藻酸钠(OSA),固定到体外循环聚氯乙烯(PVC)管路表面,评价其血液相容性和生物相容性等指标,并与空白对照组(PVCC)和进口产品美敦力肝素涂层组(PVCM)比较。结果表明,OSA涂层物有效固定在PVC管道表面,且OSA涂层管路(PVCS)具有良好的抗凝血性能,仅次于PVCM(P<0.05),显著优于PVCC(P<0.05);PVCS蛋白粘附率显著低于PVCC(P<0.05)和PVCM(P<0.05);PVCS血小板粘附量显著低于PVCC(P<0.05),与PVCM相比无显著差异(P>0.05)。PVCS与PVCM脱落率相比,有着相似的趋势。OSA涂层体外循环管路,具有良好的抗凝血性能、优越的生物相容性和较好的稳定性。     

用于体外循环管材的新型醛基化海藻酸钠-地塞米松缓释涂层研究

研制新型醛基化海藻酸钠-地塞米松缓释涂层,筛选最佳涂层模式和涂层条件,对涂层稳定性、抗凝性能、缓释性能等进行评价。高碘酸钠氧化海藻酸钠得醛基化海藻酸钠（OSA）,酸化预处理聚氯乙烯（PVC）管材表面,聚乙烯亚胺涂抹经酸化预处理的PVC管材。聚乙烯亚胺涂层管材（PP）通过离子键直接交联地塞米松磷酸钠（DSP）制备DSP单涂层管材（PPD组）,PP通过离子键交联（PPI组）、共价键交联（PPC组）两种方式制备醛基化海藻酸钠-地塞米松磷酸钠复合涂层管材,同时设置空白对照（C组）。以正交实验筛选3种涂层模式的最佳涂层条件。对3种涂层管材进行涂层物定性和定量分析,抗凝、抗血小板、抗蛋白粘附、体外释放等性能进行评价研究,从而筛选最佳涂层模式。结果显示,PPD、PPI和PPC等3种涂层模式均能固定DSP,最佳固定密度分别为(333±075)、(163±076) 、(206±068)μg/cm2;复合涂层组（PPI和PPC）血小板粘附量（109/L）分别为（1388±189）和（1913±340）,均较C组（4138±320）显著减少;复合涂层组蛋白粘附量（mg/cm2）（HAS：（2986±1357）和（4667±320）,HPF：（3499±352）和（4567±379））,均较PPD组（HAS：（6873±426）,HPF：（7254±790））显著减少;体外释放方面PPC组明显优于PPI组。醛基化海藻酸钠-地塞米松复合涂层具备良好的血液相容性和生物相容性,通过共价交联的DSP能够达到缓释效果。     

Changes in platelet aggregation during cardiopulmonary bypass: comparison of poly-2-methoxyethylacrylate and heparin as a circuit coating material

At present, there are various biomaterials that have high biocompatibility. In particular, there are many types of coated circuits in cardiopulmonary bypass (CPB) systems. However, only a few clinical studies have investigated platelet aggregation caused by these coated circuits. In this study, a CPB system coated with poly-2-methoxyethylacrylate (X coating) was used to ascertain whether platelet aggregation could be suppressed during CPB, and a comparison was made between X coating and ordinary (covalently bonded) heparin coating. The subjects were 19 adult patients who were scheduled to undergo valve replacement or valvuloplasty. They were divided into two groups: group X (X coating) and group H (heparin coating). The platelet aggregation threshold index (PATI, grading curve) and β-thromboglobulin and plalelet factor IV levels were assessed preoperatively (control), 5 min after heparin administration, 10 and 60 min after the start of CPB, and 0 and 2 h after the end of CPB. The results indicated that platelet aggregation was reduced during CPB and that platelets were activated. The changes in platelet aggregation associated with the X coating were shown to be similar to those associated with heparin coating.     

Platelet adhesion to heparin coated oxygenator fibers under in vitro static conditions: impact of temperature

Heparin coating of cardiopulmonary bypass (CPB) circuitry may attenuate the platelet consumption associated with CPB. We investigated the effect of temperature on the interaction between platelet and heparin coated surfaces under in vitro static conditions. Heparin coated and non coated oxygenator fibers were incubated with heparinized whole blood at 37 degrees C and 22 degrees C. The incubation time was set at 30, 60, 180, and 300 minutes. The number of platelets adhering to each fiber was assessed with enzyme immunoassay using monoclonal antibody against platelet receptor protein CD 61(GPIIbIIIa). As an index of platelet activation, plasma soluble(s) P-selectin levels were measured by enzyme-linked immunosorbent assay. Under normothermia, the number of adherent platelets on the non coated surface increased significantly after 300 min of incubation. Platelet adhesion was reduced significantly by heparin coating of the surface and was kept constant after 300 min. Under hypothermia, heparin coating was also associated with significant reduction of platelet adhesion. The levels of sP-selectin did not correlate with the extent of platelet adhesion. Our results suggest that heparin coating is effective in decreasing platelet adhesion to the synthetic surface tested regardless of the temperature under static conditions. Inhibition of platelet activation on the heparin coated surface may be masked by standard dose heparinization.     

Hemocompatibility of PMEA coated oxygenators used for extracorporeal circulation procedures

An inflammatory response to cardiopulmonary bypass (CPB) caused by bioincompatibility of extracorporeal circuits is one of the major clinical issues in cardiac surgery. Recently a new coating material, poly-2-methoxyethylacrylate (PMEA), was developed to improve the biocompatibility of blood contacting surfaces. In a simulated cardiopulmonary bypass model, using fresh human whole blood, 15 membrane oxygenators (Capiox SX18, Terumo Corp., Tokyo, Japan) were compared. Five of them had the PMEA coating, five had a heparin-coated surface, and five had no surface treatment. Blood samples were taken at several time-points during a 90 minute circulation period. Changes in coagulation, complement, and blood cell alteration factors were measured by ELISA methods, plasma bradykinin levels were measured by radioimmunoassay, and expression of genes encoding cytokines TNF-alpha, interleukin-1beta, interleukin-6, and interleukin-8 was determined by semiquantitative real time RT-PCR. Platelet adhesion was significantly reduced in both the PMEA and the heparin coated circuits. Release of platelet activation marker beta-thromboglobulin was significantly higher in the uncoated control group (p < 0.01). After 5 minutes of blood circulation bradykinin levels significantly increased in all three groups (p < 0.01); however, the group with the PMEA coated oxygenators showed the lowest values. Expression of genes encoding proinflammatory cytokines in monocytes was increased in all groups, with the lowest being in the PMEA coated group. PMEA coated CPB surfaces in an in vitro experimental model showed an improved thrombogenicity, reduced bradykinin release, less platelet activation and less proinflammatory cytokines gene expression in comparison with a noncoated group. The authors assume that PMEA coating may ameliorate some of intra- and postperfusion syndromes, particularly hypotension, unspecific inflammation, hyperfibrinolysis, and blood loss.     

The impact of heparin coated circuits upon metabolism in vital organs: effect upon cerebral and renal function during and after cardiopulmonary bypass

During cardiopulmonary bypass (CPB), the brain and the kidneys may be damaged because of microemboli, ischemia, and inflammation. The latter has been reduced by the use of heparin coated circuits. We questioned whether heparin coated circuits could also reduce cerebral and renal damage and whether inflammatory markers correlate with damage to the brain and the kidneys. Fifty-one patients scheduled for coronary artery bypass grafting were perfused with either a heparin coated or an uncoated circuit. To compare the effect of a heparin coated circuit with an uncoated circuit upon cerebral and renal function in relation to inflammation, we assessed markers of cerebral (S100beta) and renal (N-acetyl-beta-D-glucosaminidase [NAG], creatinine, and urea) function, inflammation, and oxygen metabolism. S100beta levels and NAG levels increased during CPB in both groups as compared with baseline levels (p < 0.01), without differences between the groups. After 15 minutes on CPB, C4b/c levels were significantly higher in the coated group compared with the uncoated group (p < 0.02). C4b/c correlated with S100beta (p < 0.01). Total body oxygen delivery (DO2) and consumption (VO2) decreased significantly in both groups during CPB (p < 0.01), but recovery was better in the coated group. After protamine infusion, total body oxygen delivery and consumption correlated negatively with S100beta levels (both p < 0.05) and with NAG levels (both p < 0.01). This study suggests that, if adequate tissue perfusion is not maintained, the use of a heparin coated circuit gives no additional benefit beyond that of the uncoated circuit. The inverse relationship of both cerebral and renal markers with DO2 and VO2 suggests that increased levels of S100beta and NAG during CPB may primarily be caused by an oxygen deficit and secondary to the inflammatory response.     

PMEA coating of pump circuit and oxygenator may attenuate the early systemic inflammatory response in cardiopulmonary bypass surgery

We investigated the effects of coating a cardiopulmonary bypass (CPB) circuit and oxygenator with poly-2-methoxy-ethyl acrylate (PMEA) on the systemic inflammatory response during and after CPB. Thirty patients undergoing elective cardiac surgery were randomized into three groups (each group n = 10): noncoated (group N), heparin coated (group H), and PMEA coated circuit and oxygenator (group X). Bradykinin (BK), complement 3 activation (C3a) and interleukin-6 (IL-6) levels were measured as early phase indicators of inflammatory response, as were maximum C reactive proteins (CRP) and white blood cell (WBC) levels. The alveolar-arterial oxygen gradient (A-a DO2) was measured as a parameter of respiratory function. IL-6 levels after CPB were significantly higher in group N than in groups H and X (p < 0.05). Serum BK and C3a levels showed similar patterns in all groups. A-a DO2 was lower at the end of and 3 hours after CPB in groups H and X than in group N (p < 0.05). Maximum CRP levels were lower in group X than in groups N (p < 0.05). This prospective study suggests that PMEA coated CPB may improve respiratory function and decrease systemic inflammatory response after cardiac surgery, possibly because this circuit is as biocompatible as heparin coated CPB circuit.     

In vivo evaluation of a new surfactant polymer coating mimicking the glycocalyx of endothelial cells

The purpose of this study was to demonstrate that a proprietary surfactant polymer (SP) coating does not adversely affect the hemodynamic performance of cardiopulmonary bypass (CPB) or gas exchange in oxygenators. The new coating was applied to a CPB circuit including cannulae, reservoir, oxygenator, and blood pump implanted into 12 pigs, divided into groups with either coated or noncoated pumps. CPB flow was maintained at a fixed level of approximately 2.4 L/min for 6 hours with full heparinization. Hemodynamic data and pump performance were recorded every hour, and blood samples were taken every 2 hours. After sacrifice, the CPB circuit and major organs were macroscopically examined. There was no significant difference in the oxygen transfer rate between the two groups. The coating did not adversely affect oxygenator inlet or outlet pressures. There was no significant difference between the two groups in microthrombi seen in the oxygenators. No thromboemboli were noted in the major organs on gross or histologic examination. In conclusion, this new SP coating did not decrease gas exchange performance, and its biocompatibility evaluations revealed no differences between coated and noncoated groups under aggressive heparin use.     

Cytokine mediated endothelial activation during and after normothermic cardiopulmonary bypass: heparin-bonded versus non heparin-bonded circuits

Studies evaluating cytokine production under normothermic cardiopulmonary bypass (CPB) are limited. We evaluated cytokine production, levels of thrombomodulin (TM), and soluble endothelium-derived adhesion molecules (ICAM-1) under normothermic CPB with and without heparin-bonded circuits. Nine patients treated with non heparin-bonded circuits (control group), and seven patients treated with heparin-bonded circuits (heparin group) were the subjects. Granulocyte elastase (G-E), and interleukin (IL) -6 and IL-8 were chosen as proinflammatory mediators, and TM and ICAM-1 served as indicators for endothelial damage. Blood samples were obtained before CPB, 30 minutes after initiation of CPB, at the termination of CPB, and 2 and 24 hours after CPB. G-E values in the heparin group were lower than those in the control group after 30 minutes of CPB. A G-E surge occurred at the end of CPB, and IL-6 and IL-8 surges were observed 2 hours after CPB in both groups. TM and ICAM-1 values, which were reduced at the initiation of CPB, returned to initial levels 2 hours after CPB, and exceeded them 24 hours after CPB compared with preCPB levels. Both groups showed similar changes. We conclude that there are no significant differences in serial G-E, IL-6, IL-8, TM, or ICAM-1 levels between the heparin and control groups during or after normothermic CPB for 2 to 3 hours.