Review: Understanding sorbent dialysis systems

Although maintenance haemodialysis once had the benefit of two distinctly different dialysate preparation and delivery systems – (1) a pre‐filtration and reverse osmosis water preparation plant linked to a single pass proportioning system and (2) a sorbent column dependent dialysate regeneration and recirculation system known as the REDY system – the first came to dominate the market and the second waned. By the early 1990s, the REDY had disappeared from clinical use. The REDY system had strengths. It was a small, mobile, portable and water‐efficient, only 6 L of untreated water being required for each dialysis. In comparison, single pass systems are bulky, immobile and water (and power) voracious, typically needing 400–600 L/treatment of expensively pretreated water. A resurgence of interest in home haemodialysis – short and long, intermittent and daily – has provided impetus to redirect technological research into cost‐competitive systems. Miniaturization, portability, flexibility, water‐use efficiency and ‘wearability’ are ultimate goals. Sorbent systems are proving an integral component of this effort. In sorbent dialysate regeneration, rather than draining solute‐rich dialyser effluent to waste – as do current systems – the effluent repetitively recirculates across a sorbent column capable of adsorption, ion exchange or catalytic conversion of all solute such that, at exit from the column, an ultra‐pure water solution emerges. This then remixes with a known electrolyte concentrate for representation to the dialyser. As the same small water volume can recirculate, at least until column exhaustion, water source independence is assured. Many current technological developments in dialysis equipment are now focusing on sorbent‐based dialysate circuitry. Although possibly déjà vu for some, it is timely for a brief review of sorbent chemistry and its application to dialysis systems.     

维持性血液透析患者血清和透析液对脂肪细胞凋亡的影响

目的 观察维持性血液透析（HD）患者血清及其与常规透析液（CD）或高纯透析液（HPD）联合干预对脂肪细胞凋亡的影响。方法 采集20例HD患者（CD和HPD治疗各10例）血样并分离血清,ELISA法检测血清肿瘤坏死因子α(TNF-α) 水平。分别以HD患者血清（HDPS组）、HD患者血清联合CD（HDPS+CD组）和HD患者血清联合HPD（HDPS+ HPD组）对经体外诱导分化成熟的3T3-L1脂肪细胞进行干预,48 h后收集细胞。Hoechst 33258染色荧光显微镜观察细胞形态学改变;Annexin-V-FITC/PI双标记流式细胞术检测细胞凋亡。PCR检测CD和HPD中细菌DNA片段表达。结果 ELISA法检测结果显示,与HPD治疗HD患者比较,CD治疗HD患者血清TNFα水平显著升高（P<0.05）。在HDPS组和HDPS+CD组,荧光显微镜观察可见呈典型凋亡形态学改变的细胞增多,两组细胞凋亡率均显著高于HDPS+HPD组（P<0.05）。PCR检测显示,CD和HPD中细菌DNA表达分别为902.79±60.57和454.87±32.22,两者差异有统计学意义（P<0.05）。结论 HDPS可诱导3T3-L1脂肪细胞凋亡,可能与患者血清TNF-α水平升高有关。与HD患者血清联合CD干预比较,联合HPD干预诱导的脂肪细胞凋亡率较低且HPD中细菌DNA表达较少。     

维生素C透析液对继发性甲状旁腺功能亢进的影响

目的了解维生素C透析液对维持性血液透析患者继发性甲状旁腺功能亢进的影响。方法选择在郑州大学第一附属医院血液净化中心长期透析的患者82例,随机分成两组,分别使用常规透析液(A组40例)和含维生素C透析液(B组42例)进行血液透析,周期为3个月,试验开始前及3个月后分别于透析前抽血化验血清全段甲状旁腺素(intact parathyroid hormone,iPTH)、钙、磷、钙磷乘积、碱性磷酸酶(alkaline phosphatase,ALP)、维生素C水平。结果 A组试验3个月后血清iPTH、ALP轻度升高,钙、磷、钙磷乘积无明显变化,差异无统计学意义(P0.05),维生素C降低,差异有统计学意义(t=-2.35,P0.05);B组试验3个月后血清iPTH、ALP明显降低,差异有统计学意义(P0.05),钙、磷、钙磷乘积无明显变化,维生素C轻度升高,差异无统计学意义(t=0.14,P0.05)。结论常规透析使大量维生素C丢失;维生素C可以降低血清iPTH、ALP,预防继发性甲状旁腺功能亢进。     

高糖腹膜透析液对小鼠腹腔巨噬细胞活力和NO产生的影响

目的探讨商业用腹膜透析液(commercial peritoneal dialysate,CDS)对腹腔巨噬细胞功能的影响.方法培养的小鼠腹腔巨噬细胞(Mφ)在含不同葡萄糖浓度(15、25和42 g/L)的CDS中,经不同时间(10、30和60 min)的暴露,观察MФ还原MTF的能力及其NO的产量.结果低葡萄糖浓度(25 g/L)暴露10 min实验组,MФ还原MTT的能力(A570nm值)为0.210±0.008,NO的产量为(9.1±1.3)μmol/L,均明显低于对照组(P＜0.01);高葡萄糖浓度(42 g/L)和较长时间(60 min)暴露组,MФ还原MTF的能力(A570nm值)为0.056±0.004,NO的产量为(5.7±1.1)μmol/L,与对照组相比较,改变最明显(P＜0.01).结论短时间CDS暴露,即可降低MФ的活力及NO产生,这种作用与CDS中的葡萄糖浓度以及MФ暴露于CDS的时间呈正相关.     

无糖型碳酸氢盐透析液的配制与临床应用

目的 :探讨无糖型碳酸氢盐透析液的配制及其临床应用。方法 :采用无糖型碳酸氢盐透析液组方 ,用于185例慢性肾功能衰竭患者进行血液透析。结果 :共配制 2 18次 ,经 85 0 8次透析 ,透析后各离子浓度符合要求。结论 :本制剂用于慢性肾功能衰竭患者血液透析 ,质量稳定 ,效果良好。     

血液透析患者应用低钙透析液的临床研究

目的：探讨维持性血液透析患者如何应用低钙透析液。方法：将43例试验前长期应用1.25 mmol/L低钙透析液的维持性血液透析患者随机分入试验组（T组）（20例）和对照组（C组）（23例）。根据入组时血全段甲状旁腺激素（intact parathyroid hormone,iPTH）水平〈500 ng/L或≥500 ng/L,T组和C组又分别分为T1组（9例）、T2组（11例）和C1组（15例）、C2组（8例）。入组后T组改用1.50 mmol/L钙浓度血液透析液,C组继续应用1.25 mmol/L钙浓度血液透析液。分别在入组时和入组6个月后检测T组和C组透析前血iPTH水平、血钙及血磷水平,计算钙磷乘积,并进行入组前后和组间的比较。结果：T1组的血iPTH水平有下降的趋势,但与入组前比较差异无统计学意义（P〉0.05）;T1组的血钙、血磷及钙磷乘积水平与入组前比较变化均不明显（P〉0.05）。T2组的血iPTH水平显著下降（P〈0.01）,血磷水平也有明显下降（P〈0.05）;而T2组的血钙和钙磷乘积水平无变化（P〉0.05）。C1组和C2组的血iPTH水平、血钙、血磷及钙磷乘积水平与入组前比较差异均无统计学意义（P〉0.05）。结论：对于伴中重度继发性甲旁亢（iPTH水平≥500 ng/L）、血钙正常或偏低的血液透析患者,长期应用1.25 mmol/L钙浓度透析液可能加重甲状旁腺功能亢进。这类患者选择1.50 mmol/L钙浓度的血液透析液有利于降低血iPTH水平,还可降低血磷水平,而不会升高血钙水平。     

在线尿素清除率监测仪检测透析充分性的准确性

目的 探讨在线尿素清除率监测仪(OCM)监测血液透析患者透析充分性的准确性及其应用价值.方法 19例行规律性血液透析的无尿患者于治疗开始后0.5、1、2、3、4 h分别留取部分收集法(PDC)及全部收集法(TDC)透析液样本,测定尿素氮,检验PDC方法 的精确性并计算直接定量法获得的尿素清除指数(Kt/V,DDQ Kt/V).于透析开始前、透析结束即刻及透析结束后30 min时采血测定尿素氮并通过DaugirdasⅡ公式计算单室Kt/V(Sp Kt/V),采用更接近双室水平的速率公式、平衡公式计算Ra Kt/V、Eq Kt/V,使用费森尤斯公司OCM模块监测Kt/V(OCM Kt/V).比较不同方法 得到的Kt/V水平及其相关性,比较OCM内置Watson公式、Hume-Weyers公式、体重推导公式计算患者尿素分布容积(Vurea)与直接定量法计算获得的Vurea之间的差异.结果 PDC法收集的透析废液的尿素氮水平为(5.15±1.85)mmol/L,与TDC法[(5.37±1.90)mmol/L]的差异无统计学意义(P=0.534).Pearson相关检验显示,PDC与TDC两种方法 测定的尿素氮浓度呈正相关(r=0.955,P＜0.05).Bland-Altman检验显示,PDC与TDC两种方法 获得的透析废液标本中尿素氮水平具有非常好的一致性.DDQ Kt/V值为1.34±0.26,OCM Kt/V值为1.24±0.24,SpKt/V值为1.58±0.27,Ra Kt/V值为1.39±0.24,Eq Kt/V值为1.41±0.27.Sp Kt/V值显著高于DDQ Kt/V值、OCM Kt/V值、Ra Kt/V值、Eq VKt/V值(P值均＜0.05),而OCM Kt/V值、Ra Kt/V值、Eq Kt/V值与DDQ K1/V值的差异均无统计学意义(P值均＞0.05).Pearson相关分析显示,OCM Kt/V值与DDQ Kt/V值、Sp Kt/V值、Ra Kt/V值、Eq Kt/V值呈正相关(P值均＜0.05),r值分别为O.706、0.594、0.605、0.731,OCM Kt/V值与DDQ Kt/V值、Eq Kt/V值、Ra Kt/V值之间的相关性均高于OCM Kt/V值与Sp Kt/V值;Sp Kt/V值、Ra Kt/V值、Eq Kt/V值与DDQ Kt/V值呈正相关(P值均＜0.05),r值分别为0.901、0.891、0.963,均优于OCM Kt/V值与DDQ Kt/V值之间的相关性值.通过Watson公式、Hume-Weyers公式及体重推算公式计算获得的Vurea分别为(34.10±4.25)、(35.93±4.28)、(33.79±6.93)L,均显著高于DDQ方法 获得的Vurea[(28.23±9.27)L,P值均＜0.05].结论 OCM Kt/V与患者实际获得的透析剂量相似且存在良好的相关性,可能作为患者实际获得的透析剂量的一种较可靠的测量方法,且可以实时监测,应进一步推广与验证.     

高糖腹透液对腹膜间皮细胞分泌VEGF的影响及氟伐他汀的干预作用

目的:观察氟伐他汀(fluvastatin,Flu)对高糖腹透液(high-glucose peritoneal dialysate,HGPDS)诱导的人腹膜间皮细胞(human peritoneal mesothelial cells,HPMCs)分泌血管内皮生长因子(vascular endothelial growth factor,VEGF)的影响?方法:体外培养HPMCs,同步化48 h后,分组如下:正常对照组?HGPDS组?HGPDS+Flu组?单纯Flu组?倒置显微镜观察各组细胞形态,RT-PCR法检测各组VEGF的mRNA表达,Western blot检测各组VEGF蛋白的表达?结果:与正常对照组相比,在HGPDS作用下,48 h后细胞由铺路石样转变为长梭形,1 × 10-6 mol/L Flu可部分逆转HPMCs的形态改变?与正常对照组相比,在HGPDS作用下,人腹膜间皮细胞VEGF mRNA及蛋白表达明显增多(P < 0.05),并呈时间依赖性,VEGF mRNA和蛋白分别在HGPDS干预后12 h和48 h达高峰(P < 0.05)?Flu可明显抑制HGPDS诱导的VEGF的表达(P < 0.05),并呈浓度依赖性?结论:适当浓度的Flu可以抑制HGPDS刺激体外培养人腹膜间皮细胞VEGF表达增加?     

Calcium balance in hemodialysis: More uncertainty than certainty

There is controversy about the choice of dialysate calcium concentration (DCa), with strong arguments both in favor of and against the use of a low or high DCa, as they can both be potentially harmful. Evidence suggests that calcium mass balance is positive with a DCa 3.5 mEq/L, negative or neutral with the use of DCa 2.5 mEq/L, whereas both positive and negative balances have been observed with the use of DCa 3.0 mEq/L. Overall, the use of DCa >2.5 mEq/L is usually associated with an increase in serum calcium level and a decrease in serum PTH level and use of lower vitamin D analogue dose, with the opposite effects usually observed with the use of lower DCa. Most of the available evidence is from small-sized and crossover studies; hence, evidence should be regarded with caution and applied in a patient-specific manner. As there are a lot of significant unanswered questions regarding calcium balance and the optimal DCa in hemodialysis patients, further high-quality research is needed to clarify many still unclear aspects of calcium homeostasis and balance in these patients. In conclusion, with the existing evidence the choice of DCa needs to be individualized and contextualized in the setting of each patient's calcium balance needs and homeostatic response, taking also into account oral calcium intake (dietary and medicinal), any other relevant therapy administered, such as vitamin D analogues, the type of renal mineral bone disorder, and associated cardiovascular comorbidity.