Experimental Results Using Nafamostat Mesilate as Anticoagulant During Extracorporeal Lung Assist for 24 Hours in Dogs

Abstract: We report on the experimental application of nafamostat mesilate (NM, 6-amidino-2-naphthyl p -guanidinobenzoate dimethanesulfonate, FUT®), a new anticoagulant, to extracorporeal lung assist (ECLA) with an artificial membrane lung. Venovenous ECLA, from the jugular vein to the femoral vein, was performed with a hollow-fiber membrane lung at a blood flow rate of approximate 82 ml kg^-1 min^-1 for 24 h in 7 dogs under anesthesia and hypoventilation. Heparin (10 U ml^-1 in a priming lactated Ringer solution of 140 ml, and 200 U kg^-1) was administered before blood access cannulation. After start of ECLA, however, no heparin was used, and nafamostat mesilate was continuously infused into the drainage line of the bypass circuit to control activated coagulation time (ACT) at about 150 to 200s. To maintain the prolonged ACT, 8:0 ± 1.7 mg kg^-1 h^-1 of NM was required. Arterial blood pressure and pulse rate decreased significantly. Though fibrin monomer test revealed hypercoagulability after 6 h of ECLA, platelet counts did not significantly decrease. Total blood loss remained less than 40 g. The artificial membrane lung sustained a good gas exchange and low flow resistance throughout ECLA. Macroscopic examination revealed small spotty thrombi in the artificial lung but no major pathologic changes of the visceral organs in the all dogs at autopsy. High-dose NM administration could control blood coagulation and decrease blood loss during ECLA for 24 h without deterioration of the artificial lung and systemic complication other than mild hypotension and bradycardia.     

Proteins Adsorbed on Hemodialysis Membranes Modulate Neutrophil Activation

The rapid adsorption of plasma proteins is one of the initial events that occur when blood enters into contact with an artificial surface. This study investigates adsorption of plasma proteins in vitro by different types of dialysis membranes and how it influences neutrophil oxygen radical production. The recovery of proteins varied between the membranes and was by far the largest on polysulfone. Electrophoresis of the proteins removed indicated that albumin was present on all of the membranes. A specific band at 45 kD was observed on polysulfone, whereas a band at 12-14 kD was seen on polysulfone and polyacrilonitrile. The adsorbed proteins enhanced or reduced the ability of the membranes to stimulate neutrophil superoxide production, as measured by cytochrome-C reduction. The complement system was involved in this stimulation only on some membranes. Therefore, protein adsorption and neutrophil activation appear to take part in the membrane bioincompatibility process.     

Differences in Bio-incompatibility among Four Biocompatible Dialyzer Membranes Using in Maintenance Hemodialysis Patients

Abstract

Background: Following the introduction of modified cellulosic and then synthetic membrane dialyzers, it was realized that the dialyzer bio-incompatibility depends on the membrane composition. We designed a prospective, randomized, cohort study of 6 months to determine several parameters of biocompatibility in maintenance hemodialysis (MHD) patients treated with four different membrane dialyzers. Methods: There were 60 MHD patients enrolled in the study. In baseline, synthetic low-flux dialyzer, polysulfone (PS) membrane was used in all patients for at least 3 months. Then the patients were randomly divided into three groups according to different dialyzer membranes. Synthetic high-flux dialyzer group, ployethersulfone membrane, cellulose triacetate (CTA) high-flux membrane, and synthetic low-flux dialyzer, polymethylmethacrylate (PMMA) membrane were used in 6 months. A new dialyzer was used for each study treatment, and there was no dialyzer reuse. The biocompatibility markers and solutes removal markers were detected repeatedly at different time points. Results: The blood levels of highly sensitive C reactive protein, interleukin (IL)-1β, and interleukin (IL)-13 showed no difference among different groups at al time points. However, the blood complement levels and white blood cell counts were significantly different among three groups. When the dialyzers changed from PS to PMMA membrane, C3a levels and white blood cell counts changed significantly (p < 0.05). Moreover, the changes of C5a levels were significantly different between group CTA and group PMMA in month 3 (p < 0.05). Conclusion: There were much more differences on bio-incompatibility among different dialyzer membranes.     

Net Ultrafiltration May Not Eliminate Backfiltration During Hemodialysis with Highly Permeable Membranes

Backfiltration of dialysis solution can occur during hemodialysis with highly permeable membranes. A method has recently been developed for determining backfiltration rates in vitro at low dialysate flow rates by measuring changes in the local dialysate concentration of a marker macromolecule via sampling ports added to the hemodialyzer housing. In the present study, the influence of net ultrafiltration on backfiltration rates was determined for five commercial dialyzers containing membranes with different water permeabilities. In vitro experiments were performed (n = 3) using freshly donated whole blood at blood flow rates of 200 and 340 ml/min and at a dialysate flow rate of 100 ml/min. At zero net ultrafiltration, backfiltration rates increased with increasing membrane water permeability and ranged from 0.9 to 6.9 ml/min. At a net ultrafiltration rate of 10 ml/min, backfiltration was eliminated for dialyzers containing membranes with water permeabilities of less than 30 ml/h/mm Hg but remained significant for dialyzers with higher membrane water permeabilities. Therefore, despite a significant net ultrafiltration rate, backfiltration may still occur during hemodialysis with highly permeable membranes.     

甲磺酸萘莫司他中有机溶剂残留的测定

目的建立气相色谱法测定甲磺酸萘莫司他中有机溶剂残留量。方法在EC-1000（30m×0．54mm×1．2μm）毛细管柱上采用程序升温法,载气为氮气,汽化室温度200℃,检测器温度220℃,以二氧六环为内标,内标法测定甲碳酸萘莫司他中残留的甲醇、丙酮、毗啶、N,N-二甲基甲酰胺。结果在本研究色谱条件下,各溶剂及内标均能得刮良好的分离度,空白无干扰;在所考察的浓度范围内线性良好,相关系数均在0．9996以上,回收率96．7％～102．0％,检测限0．15—2．8μg／mL。结论试验建立的色谱方法简便、准确,灵敏度高,适合甲磺酸萘莫司他机溶剂残留量的检测。     

Influence of Hemodialysis Membranes on Gene Expression and Plasma Levels of Interleukin-iβ

Abstract: Plasma levels of interleukin-iβ (IL-iβ) were measured in 10 normal subjects, in 11 nondialyzed end-stage renal failure (ESRD) patients, and in 22 hemodialysis (HD) patients. Of the HD patients, 7 were dialyzed with Cuprophan (CU), 7 with polymethylmethacrylate (PMMA), and 8 with polysulphone (PS) dialyzers. In normal controls, nondialyzed ESRD patients, and HD equipped with CU, PAMM, and PS dialyzers, plasma levels of IL-iβ were 10.73 ± 5.24 pg/ml, 9.97 ± 3.61 pg/ml, 13.17 ± 4.04 pg/ml, 15.16 ± 6.16 pg/ml, and 13.96 ± 5.47 pg/ml, respectively. There were no statistically significant differences among the groups (p ≥ 0.05). In contrast, the gene expression of IL-iβ for peripheral blood mononu-clear cells (PBMC) by in situ hybridization showed differences among the groups. The gene for IL-iβ for PBMC appears in HD equipped with different membranes, but not in cases of nondialyzed uremic patients and normal subjects. With computer imaging analysis, we carried out quantitative analysis of cells in in situ hybridization with an area of positive spots to an area of total cells. In HD with CU, PMMA, and PS, the results were 10.64 ± 1.07, 3.34 ± 0.74, and 3.27 ± 0.64%, respectively. The levels of IL-iβ gene expression in CU were higher than that in PMMA or PS. There were statistically significant differences (p ≤ 0.001) between CU and PMMA or PS and no significant difference between the PMMA and PS (p ≥ 0.05). We suggest measuring the gene expression of cy-tokines for PBMC and which may be better than measuring cytokine levels only for investigating the blood compatibility of dialyzers, which may help in understanding chronic complications of the dialysis procedure.     

Superior Outcome of Nafamostat Mesilate as an Anticoagulant in Patients Undergoing Maintenance Hemodialysis with Intracerebral Hemorrhage

Aims. The incidence of complications associated with cerebrovascular diseases in patients who receive hemodialysis for a long-term period is higher than that of other complications. It is known that mortality due to cerebral hemorrhage is two times higher compared to non-dialysis patients. Anti-coagulants used for hemodialysis are essential. Accordingly, in cases in which the cerebral hemorrhage occurred, the selection of anti-coagulants for the prevention of further bleeding poses a great challenge to physicians. The change of hematoma and patient prognosis has a direct relationship. Many ongoing studies are conducted to examine the causative factors causing the increased hematoma and their related prognostic factors. In the current study, we examined the effect of nafamostat mesylate (a serine protease inhibitor) on the change of hematoma compared to heparin in hemodialysis patients.?Methods. The current study was conducted in 17 hemodialysis patients who developed a cerebral hemorrhage. These patients were assigned to two groups based on the type of anti-coagulants that they used (i.e., nafamostat mesylate and heparin). Then, the factors affecting the change of hematoma following the onset of cerebral hemorrhage were examined. The prognosis of hematoma was assessed based on brain CT scans, which were performed two weeks after the onset of cerebral hemorrhage in four groups. Following this, groups 1 (the decreased hematoma) and 2 (the decreased delay) were merged to group A (resolving group), and groups 3 (the increased hematoma) and 4 (the death following the aggravation) were merged to group B (the expansion group) for further analysis. Results. There were no significant differences in baseline characteristics between the nafamostat group and the heparin group. A comparison between the resolving group and the expansion group also showed that there were no significant differences in baseline characteristics. In the anti-coagulants and the change of hematoma, however, there were significant differences between the two groups (p = 0.024). A comparison of the change of hematoma between the four groups was also made. This showed that platelet counts and BUN level were significant factors (Platelet; p = 0.042, BUN; p = 0.043 ANOVA with resolving group). Conclusions. Nafamostat mesylate has a similar profile of anti-coagulative activity to heparin. It is assumed, however, that nafamostat has an affirmative effect on the recovery of damaged sites following the onset of cerebral hemorrhage. It is an anti-coagulant that can be safely used for hemodialysis following the onset of cerebral hemorrhage.     

Eluted Substances From Hemodialysis Membranes Elicit Positive Skin Prick Tests in Bioincompatible Patients

Recently, hypotension and malaise during hemodialysis using polysulfone (PS) membranes have been reported. This study aimed to evaluate the bioincompatibility of eluted substances from PS hemodialysis membranes that can induce hypotension, malaise, and anaphylactic shock. Polyvinylpyrrolidone (PVP) elution from five hemodialysis membranes was measured in an in vitro experimental circulation. Skin prick tests (SPTs) with PVP or the priming fluid of hemodialysis membranes were carried out for seven PS membrane‐incompatible patients and seven healthy volunteers. Skin reactivity for histamine was compared in patients and healthy volunteers. The symptoms of PS membrane‐incompatible cases were hypotension, dyspnea, nausea, or vomiting. One patient had gone into shock. PVP was eluted from hemodialysis membranes, but the SPT for PVP was negative in all patients. SPTs with priming fluid (or priming fluid effluxed during priming) were positive in four out of six patients. However, the SPT with bisphenol A was positive in one patient. The area of the flare reaction against histamine in patients was smaller than that of healthy subjects. In conclusion, eluted substances apart from PVP from hemodialysis membranes could cause bioincompatibility with PS membranes.     

Hemodialysis with Regenerated Cellulosic Membranes Does Not Reduce Plasma Selenium Levels in Chronic Uremic Patients

Abstract: Selenium (Se) is considered an essential and very important trace element for humans. Se blood levels are frequently low in end-stage renal disease (ESRD) patients, but very little has been established concerning the mechanisms that could modify Se status in uremia, including a supposed dialysis-mediated Se depletion. In order to verify whether hemodialysis (HD) can induce a loss of Se, thereby leading or contributing to a low plasma Se concentration, we investigated the effect of HD procedure with the most commonly used regenerated cellulosic membrane (Cuprophan) on plasma Se levels in 20 uremic patients on HD for 62.5 ± 49.4 months. Plasma Se levels were also determined in 15 chronic renal failure (CRF) nondialyzed patients and in 28 age-matched healthy controls. Se concentration was determined by atomic absorption spectrophotometry. Plasma Se levels of both HD patients (61.3 ± 8.5 μ/L) and CRF nondialyzed patients (56.4 ± 10.1 μg/L) were significantly lower than in normal subjects (78.3 ± 9.7 μg/L, p < 0.001). In CRF nondia-lyzed patients, a significant (p < 0.05) negative correlation was found between the plasma Se concentration versus serum creatinine values. Within the HD group, plasma Se levels significantly increased after the HD procedure (72.8 ± 17.2 μg/L, p < 0.02) together with hemat-ocrit and total plasma protein values (p < 0.05 and p < 0.001, respectively). In the hollow fiber dialyzer during an HD session, the Se concentration increased but not significantly from the blood inflow site (64.6 ± 12.5 μg/L) to the outflow site (72.6 ± 17 μg/L) and decreased, again not significantly, from the dialysate entrance (5 ± 1.9 μg/L) to the outlet (4.8 ± 2.5 μ?.). In HD with low-flux regenerated cellulosic dialyzer, very likely due to the high molecular weight of Se-binding proteins, the replacement treatment did not induce a Se loss in chronic uremic patients with a low plasma Se concentration.     

Determinants of Ammonia Clearance by Hemodialysis

Abstract: Ammonia toxicity appears to contribute to the genesis of brain edema, a leading cause of death in fulminant hepatic failure. Because dialysis has been recommended for acute hyperammonemia in other conditions, we have conducted a study to analyze the determinants of ammonia clearance with the use of a single-pass dialyzer. We have used an ionic solution with a constant concentration of ammonia to estimate clearance at different blood flow rates, at dialysate flow rates, and with different dialyzer surfaces. Once hemodialysis had been optimized, we estimated ammonia, glutamine, and urea removal by using a single-compartment model. Our results show that the clearance of ammonia is blood flow dependent and is also influenced by dialysate flow rate and dialyzer surface. At clinically feasible conditions, ammonia can be extracted by more than 80% by setting the dialysate flow at a high rate. In addition to ammonia removal, hemodialysis allows the clearance of urea and glutamine, molecules that can be regarded as ammonia equivalents and that also undergo flow-dependent elimination.     

Evolution of Gas Permeable Membranes for Extracorporeal Membrane Oxygenation

Gas permeable membranes are a vital component of extracorporeal membrane oxygenation systems. Over more than half a century, membrane fabrication and packaging technology have progressed to enable safer and longer duration use of respiratory life support. Current research efforts seek to improve membrane efficiency and hemocompatibility, with the aim of producing smaller and more robust systems for ambulatory use. This review explores past and present innovations in oxygenator technology, suggesting possible applications of state‐of‐the‐art membrane fabrication methods to address shortcomings of earlier concepts.     

Prevention of Platelet Deposition and Thrombus Formationon Hemodialysis Membranes: A Double-Blind Randomized Trial of Aspirin and Dipyridamole

Abstract: A double-blind crossover study comparing low-dose aspirin (ASA) and dipyridamole (DPM) (100 mg ASA+75 mg DPM, t.d.s.), high-dose ASA and DPM (300 mg ASA+75 mg DPM, t.d.s.), and placebo on platelet deposition and thrombus formation on hemodialysis membranes was undertaken in 17 long-term dialysis patients. The high-dose combination significantly reduced the fall in platelet count during dialysis and also significantly increased postdialysis heparin concentrations. Scanning electron microscopy of the Cuprophan membranes showed a reduction in platelet desposition and fibrin formation during both treatment schedules, but this was most marked with the high-dose combination. The results of this study indicate that there is a graded response to combined ASA-DPM treatment and that this can significantly reduce platelet consumption and contact activation of fibrin during hemodialysis with Cuprophan membranes.     

Systemic Levels of Tumor Necrosis Factor Alpha During Hemodialysis with Cellulosic Membranes: No Effect of the Sterilization Procedure

Extractable constituents of dialyzer membranes (e.g., monomers and beta-glucans) may induce the production of cytokines in vitro. We therefore studied circulating tumor necrosis factor alpha (TNF alpha) levels in 23 stable hemodialysis patients during treatment with dry Cuprophan membranes (ETO-sterilized n = 10, steam-sterilized n = 13) longitudinally over a period of 4 weeks. After 4 weeks, those 5 patients of each group showing the highest TNF alpha levels were switched to steam-sterilized, wet Cuprophan membranes. No significant increase in plasma TNF alpha was observed during hemodialysis with either ETO- or steam-sterilized dry Cuprophan membranes. A substantial TNF alpha increase (> or = 100% compared to pre-HD values), however, was observed during 14 of 84 treatment sessions. In 5 selected patients with ETO-sterilized, dry Cuprophan dialyzers, TNF alpha rose from (mean +/- SEM) 17.2 +/- 3.0 (pre-HD) to 20.9 +/- 6.2 (120 min) and 21.9 +/- 4.5 pg/ml (240 min). Corresponding levels in patients with steam-sterilized, dry Cuprophan were 16.2 +/- 5.4 (pre-HD), 21.9 +/- 6.8 (120 min), and 16.0 +/- 3.7 pg/ml (240 min), respectively. There was no difference between ETO- and steam-sterilized dialyzers. No significant reduction in mean TNF alpha plasma levels or in frequency of elevated peak levels was achieved when these patients were switched to wet Cuprophan dialyzers for another 4 weeks. It is suggested that an induction of elevated TNF alpha levels during hemodialysis is possible but is not observed regularly during treatment with Cuprophan membranes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adsorption of Human Recombinant Erythropoietin on Dialysis Membranes In Vitro

Abstract: The adsorptive characteristics of 5 dialysis membranes for recombinant human erythropoietin (EPO) were studied in vitro in a closed circuit system. For 120 min, EPO added with bovine serum was significantly adsorbed by polymethylmetacrylate (PMMA) and polyacry–lonitrile (PAN) membranes but not by Cuprophan, ethylene vinyl alcohol (EVAL), or polysulfone (PS) membranes. In addition the EPO adsorptive rate, as well as that of β₂–microglobulin (β₂–MG), was greater with a PMMA membrane than with a PAN membrane. EPO was not detected in the ultrafiltrate at 15 min with 5 membranes. These results indicate that EPO was eliminated by membrane adsorption only with some dialysis membranes.     

番茄红素对血液透析患者静脉铁剂诱导微炎症状态的影响

目的：观察维持性血液透析（MHD）患者由静脉铁剂诱导的微炎症状态,探讨番茄红素对其的干预作用。方法：60例MHD患者,随机分为对照组和试验组,每组各30例。对照组：在患者透析时给予蔗糖铁注射液100mg,2次／周,共10次,观察时间8周。试验组：除蔗糖铁注射液使用外,同时口服番茄红素胶囊,2粒／次,2次／d,用药8周,观察时间8周。观察并比较两组患者治疗前及治疗8周后的血红蛋白（Hb）、红细胞比容（Hct）、血清铁（SI）、铁蛋白（SF）、转铁蛋白饱和度（TSAT）以及白细胞介素-1β（IL-18）、白细胞介素-6（IL-6）、白细胞介素-10（IL-10）、肿瘤坏死因子（TNF—α）、C反应蛋白（CRP）等指标的变化。结果：两组患者治疗后IL-18、IL-6、TNF—α及CRP水平较治疗前均有显著性升高（P〈0．01或P〈0．05）,但是试验组升高幅度显著性小于对照组（P〈0．01）;试验组患者治疗后IL-10水平较治疗前有显著性升高（P〈0．01）,并且试验组升高幅度显著性大于对照组（P〈0．05）;两组血清IL-6、TNF—α水平均与SF呈正相关（P〈0．01）：两组Hb、Hct、SI、SF、TSAT较治疗前均有显著性升高（P〈0．01）,并且两组升高幅度相似,差异无统计学意义。结论：静脉铁剂治疗加剧了MHD患者的微炎症状态。番茄红素可减轻这种微炎症状态。     

Dialysis in Rats with Acute Renal Failure: Evaluation of Three Different Dialyzer Membranes

Abstract: Exposure to complement-activating cellulosic dialysis membranes has been claimed to adversely affect the course of acute renal failure (ARF). To test this hypothesis, male Sprague-Dawley rats were allocated to 2 groups: in Group t, ARF was induced by bilateral renal artery clamping whereas in Group 2, animals underwent a sham procedure. In each group, rats were further allocated to undergo hemodialysis with either a Cu-prophan, a Hemophan, or a polyacrylonitrile minidialyzer on Days 4 and 8 after surgery, or no dialysis. Renal function was measured by inulin clearance on the days after dialysis. Additionally, total complement activity (CH₅₀) was estimated on Days 1, 2, 4, and 8, and complement factor C3 was detected immunohistochemically. The degree of renal failure and the rate of recovery of renal function were similar in all the ARF groups irrespective of whether they had undergone dialysis or not, or of the type of the dialysis membrane. Furthermore, there were no significant differences in the course of CH₅₀ or in the amount and distribution of complement factor C3 in the kidney tissue between the rats of Groups 1 and 2. Our findings refute the hypothesis that in ischemic ARF exposure to complement-activating cellulosic dialysis membranes impairs the recovery of renal function in rats.     

In Vivo Evaluation of Platelet Activation by Different Cellulosic Membranes

Abstract: This study was undertaken to evaluate platelet activation in vivo induced by different cellulosic membranes by measuring the expression of P-selectin on the platelet surface during hemodialysis in 9 uremic patients. Hollow fiber dialyzers of similar surface with different cellulosic membranes (Cuprophan, cellulose acetate, cellulose triacetate, and Hemophan) were evaluated and compared to a synthetic membrane (polysulfone). Blood samples were obtained before hemodialysis and from the efferent and afferent limbs 5 min after the beginning of dialysis. P-select in exposure was evaluated by flow cytometry (FACScan) using a monoclonal antibody (RUU 2.17). The percentage of platelets expressing P-select in before hemodialysis and the percentage from the arterial line during hemodialysis were similar. All membranes evaluated induced platelet activation (estimated as the increase in percentage of platelets expressing P-selectin in samples obtained from the venous line with respect to the arterial line). Cuprophan induced more platelet activation than any other membrane (p < 0.05). The activation induced by cellulose acetate and cellulose triacetate membranes was also higher than that observed with Hemophan (p < 0.05). Hemophan-induced platelet activation was similar to that of polysulfone. These results indicate that all cellulosic membranes induce platelet activation during hemodialysis although there are quantitative differences among them. While Cuprophan induced the highest degree of platelet activation, Hemophan was the only cellulosic membrane that showed a degree of platelet activation similar to the biocompatible membrane polysulfone.     

Protein Adsorption by Artificial Membrane Materials Under Filtration Conditions

Abstract: Elevated plasma levels of numerous low molecular weight proteins (LMWP) in renal insufficiency are likely to contribute to the uremic syndrome. Dialysis-related amyloidosis, caused by the accumulation of β₂-microglobulin (β₂M), has highlighted the need for a renal replacement therapy that allows the elimination of LMWP in addition to small solutes. Synthetic membrane materials employed under hemofiltration conditions proved to be most effective in lowering elevated β₂M plasma levels. In addition to convection, protein adsorption to artificial membrane materials is an important mechanism for β₂M removal. Using an in vitro setup, 12 commercially available hemofilters representing 11 different membrane materials were perfused with human blood containing ¹²⁵I-labeled plasma proteins. Under filtration conditions, total protein adsorption ranged from 338–2,098 mg/m² of membrane surface, and the fraction of adsorbed LMWP varied between 14–70% of total protein adsorption and was negatively correlated to total protein adsorption. β₂M adsorption showed up to an 8-fold difference between membranes, and was negatively correlated with total protein adsorption and positively correlated with the adsorption of LMWPs.