Blood Purification最新文献

Despite comparable outcomes with the extracorporeal dialysis modalities, peritoneal dialysis (PD) is seldom considered a viable option for managing acute kidney injury (AKI) in developed and resource-rich countries, where continuous renal replacement therapies (CRRTs) are the mainstay of treating AKI. PD has fewer infrastructure requirements and has been shown to save lives during conflicts, natural disasters, and pandemics. During the ongoing COVID-19 pandemic, the developed world was confronted with a sudden surge in critically ill AKI patients requiring renal replacement therapy. There were acute shortages of CRRT machines and the trained staff to deliver those treatments. Some centres developed acute PD programmes to circumvent these issues with good results. This experience re-emphasised the suitability of PD for managing AKI. It also highlighted the need to review the current management strategies for AKI in developed countries and consider incorporating PD as a viable tool for suitable patients. This article reviews the current evidence of using PD in AKI, attempts to clarify some misconceptions about PD in AKI, and argues in favour of developing acute PD programmes.

Introduction: Hypophosphatemia is common during continuous renal replacement therapy (CRRT), but serum phosphate levels can potentially be maintained during treatment by either intravenous phosphate supplementation or addition of phosphate to renal replacement therapy (RRT) solutions.

Methods: We developed a steady-state phosphate mass balance model to assess the effects of CRRT dose on serum phosphate concentration when using both phosphate-free and phosphate-containing RRT solutions, with emphasis on low CRRT doses.

Results: The model predicted that measurements of serum phosphate concentration prior to (initial) and during CRRT (final) together with clinical data on CRRT dose, treatment duration, and phosphate supplementation can determine model patient parameters, that is, both the initial generation rate and clearance of phosphate prior to CRRT. Model parameters were then calculated from average patient data reported in several previous publications with a standard or high CRRT dose. Using representative model parameters for typical patients, predictions were then made of the effect of low CRRT dose on the change in serum phosphate levels after implementation of CRRT. The model predicted that CRRT at a low dose using phosphate-free RRT solutions will limit, but not eliminate, the incidence of hypophosphatemia. Further, the model predicted that CRRT at a low dose will have virtually no influence on the incidence of hyperphosphatemia when using phosphate-containing RRT solutions.

Conclusions: This report identifies the clinical measurements to be used with the proposed model for individualizing the CRRT dose and RRT phosphate concentration to maintain serum phosphate concentrations in a desired range.

Introduction: The TKM-101 is a new hemofiltration column packed with a polymer alloy membrane consisting of polyethersulfone, polyvinylpyrrolidone, and sulfonated poly (arylene ether) copolymers. We examined the ability of the TKM-101 column to remove cytokines and humoral mediators from blood in vitro and the effects of extracorporeal treatment with the TKM-101 column on the mortality rate and inflammatory responses to endotoxic shock in vivo.

Methods: In vitro and in vivo laboratory investigations were conducted. In the in vitro experiment, the adsorption abilities of TKM-101, AN69-ST, and control columns for cytokine-related sepsis in blood were compared using human serum samples. In the in vivo experiment, male Sprague-Dawley rats were anesthetized and injected with Escherichia coli endotoxin (15 mg/kg, intravenously). Afterward, the rats were assigned (in a double-blind manner) to one of three groups (n = 17 per group): apheresis with a control column (control group), apheresis with an AN69-ST column (AN69-ST group), or apheresis with a TKM-101 column (TKM-101 group). Outcomes were compared among the groups.

Results: In vitro, the concentrations of all evaluated cytokines significantly decreased with the TKM-101 column compared to those with the control column; however, there were no significant differences between the TKM-101 and AN69-ST columns. In vivo, the mortality rates 8 h after endotoxin injection were 65%, 29%, and 29% for the control, AN69-ST, and TKM-101 groups, respectively. Hypotension and elevated plasma cytokine concentrations were less prominent in the TKM-101 and AN69-ST groups compared to those in the control group.

Conclusions: TKM-101 effectively removed proteins of varying sizes, from small-sized proteins such as interleukin (IL)-8 to mid-sized protein such as IL-10 in vitro. Moreover, TKM-101 treatment reduced mortality and had inhibitory effects on inflammatory responses in endotoxemic rats. These findings suggest that TKM-101 treatment may be available for use in patients with sepsis and/or endotoxemia.

Introduction: The removal of low- and medium-molecular-weight proteins has been improved with online hemodiafiltration (OL-HDF) and hemodialysis using high-flux membranes; however, the outcomes of patients with end-stage kidney disease (ESKD) undergoing dialysis treatment are still worse than in the general population. α1-Microglobulin (α1-m), with a molecular weight of 33,000 Da, may contribute to dialysis-related disorders and mortality. However, the removal is insufficient even with current OL-HDF using the polysulfone (PS) membrane, which is common in Japan. Polymethylmethacrylate (PMMA) membranes can remove medium- to high-molecular-weight proteins by adsorption. This study aimed to assess the efficacy of removing medium- to high-molecular-weight proteins, such as α1-m and β2-microglobulin (β2-m), through post-dilution OL-HDF with PMMA (Post-PMMA). The assessment was conducted in comparison to pre-dilution OL-HDF with PS (Pre-PS), using an open-label, single-arm study.

Methods: Seven patients with ESKD on Pre-PS underwent Post-PMMA with replacement volume of 30 mL/min (low flow) and 50 mL/min (high flow). Clearance and removal rates of α1-m, β2-m, small molecules, inflammatory cytokines, and albumin were measured at 60 and 240 min of treatment.

Results: Clearance rates of α1-m at 60 min were -2.8 ± 5.2 mL/min with Pre-PS, -0.4 ± 2.6 mL/min with Post-PMMA (low), and 0.6 ± 3.4 mL/min with Post-PMMA (high). The removal rate of α1-m was higher in Post-PMMA than that in Pre-HDF-PS (Post-PMMA [high] 17.7 ± 5.9%, Post-PMMA [low] 15.0 ± 5.6%, and Pre-PS 4.1 ± 5.5%). Adsorption clearance of β2-m was increased with Post-PMMA. Albumin leakage in Post-PMMA was not higher than that in Pre-PS.

Conclusion: The removal rate of α1-m with Post-PMMA was higher than that with Pre-PS. The PMMA membrane adsorbed β2-m, suggesting the removal effect of medium- to high-molecular-weight proteins by the adsorption method. Since Post-PMMA effectively removes α1-m without excessive albumin leakage, it will be useful for patients with ESKD, especially those with a poor nutritional status.

Background: Historically IV and enteral fluids given during acute kidney injury (AKI) were restricted before the introduction of continuous renal replacement therapies (CRRTs) when more liberal fluids improved nutrition for the critically ill. However, fluid accumulation can occur when higher volumes each day are not considered in the fluid balance prescribing and the NET ultrafiltration (NUF) volume target.

Key messages: The delivered hours of CRRT each day are vital for achievement of fluid balance and time off therapy makes the task more challenging. Clinicians inexperienced with CRRT make this aspect of AKI management a focus of rounding with senior oversight, clear communication, and "precision" a clinical target. Sepsis-associated AKI can be a complex patient where resuscitation and admission days are with a positive fluid load and replacement mind set. Subsequent days in ICU requires fluid regulation, removal, with a comprehensive multilayered assessment before prescribing the daily fluid balance target and the required hourly NET plasma water removal rate (NUF rate). Future machines may include advanced software, new alarms - display metrics, messages and association with machine learning and "AKI models" for setting, monitoring, and guaranteeing fluid removal. This could also link to current hardware such as on-line blood volume assessment with continuous haematocrit measurement.

Summary: Fluid balance in the acutely ill is a challenge where forecasting and prediction are necessary. NUF rate and volume each hour should be tracked and adjusted to achieve the daily target. This requires human and machine connections.

Introduction: When the kidneys or liver fail, toxic metabolites accumulate in the patient's blood, causing cardiovascular and neurotoxic complications and increased mortality. Conventional membrane-based extracorporeal blood purification procedures cannot remove these toxins efficiently. The aim of this in vitro study was to determine whether commercial hemoperfusion adsorbers are suitable for removing protein-bound retention solutes from human plasma and whole blood as well as to compare the removal to conventional hemodialysis.

Methods: For in vitro testing of the removal of protein-bound substances, whole blood and plasma were spiked with uremic retention solutes (homocysteine, hippuric acid, indoxyl sulfate, 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid) and the toxins of liver failure (bilirubin, cholic acid, tryptophan, phenol). Subsequently, the protein binding of each retention solute was determined. The adsorption characteristics of the hemoperfusion adsorbers, Jafron HA and Biosky MG, both approved for the adsorption of protein-bound uremic retention solutes and Cytosorb, an adsorber recommended for adsorption of cytokines, were tested by incubating them in spiked whole blood or plasma for 1 h. Subsequently, the adsorption characteristics of the adsorbers were tested in a dynamic system. For this purpose, a 6-h in vitro hemoperfusion treatment was compared with an equally long in vitro hemodialysis treatment.

Results: Hippuric acid, homocysteine, indoxyl sulfate, and tryptophan were most effectively removed by hemodialysis. Bilirubin and cholic acid were removed best by hemoperfusion with Cytosorb. A treatment with Jafron HA and Biosky MG showed similar results for the adsorption of the tested retention solutes and were best for removing phenol. 3-Carboxy-4-methyl-5-propyl-2-furanpropionic acid could not be removed with any treatment method.

Discussion/conclusion: A combination of hemodialysis with hemoperfusion seems promising to improve the removal of some toxic metabolites in extracorporeal therapies. However, some very strongly protein-bound metabolites cannot be removed adequately with the adsorbers tested.

Selected abstracts from the 42nd Vicenza Course AKI-CRRT-ECOS and Critical Care Nephrology.

Selected abstracts from the 42nd Vicenza Course AKI-CRRT-ECOS and Critical Care Nephrology.

Background: Blood purification therapy for patients overloaded with metabolic toxins or drugs still needs improvement. Blood purification therapies, such as in hemodialysis or peritoneal dialysis can profit from a combined application with nanoparticles.

Summary: In this review, the published literature is analyzed with respect to nanomaterials that have been customized and functionalized as nano-adsorbents during blood purification therapy. Liposomes possess a distinct combined structure composed of a hydrophobic lipid bilayer and a hydrophilic core. The liposomes which have enzymes in their aqueous core or obtain specific surface modifications of the lipid bilayer can offer appreciated advantages. Preclinical and clinical experiments with such modified liposomes show that they are highly efficient and generally safe. They may serve as indirect and direct adsorption materials both in hemodialysis and peritoneal dialysis treatment for patients with renal or hepatic failure. Apart from dialysis, nanoparticles made of specially designed metal and activated carbon have also been utilized to enhance the removal of solutes during hemoadsorption. Results are a superior adsorption capacity and good hemocompatibility shown during the treatment of patients with toxication or end-stage renal disease. In summary, nanomaterials are promising tools for improving the treatment efficacy of organ failure or toxication.

Key messages: (i) The pH-transmembrane liposomes and enzyme-loaded liposomes are two representatives of liposomes with modified aqueous inner core which have been put into practice in dialysis. (ii) Unmodified or physiochemically modified liposomal bilayers are ideal binders for lipophilic protein-bound uremic toxins or cholestatic solutes, thus liposome-supported dialysis could become the next-generation hemodialysis treatment of artificial liver support system. (iii) Novel nano-based sorbents featuring large surface area, high adsorption capacity and decent biocompatibility have shown promise in the treatment of uremia, hyperbilirubinemia, intoxication, and sepsis. (vi) A major challenge of production lies in avoiding changes in physical and chemical properties induced by manufacturing and sterilizing procedures.