Creatinine Removal Research Articles

Can one long peritoneal dwell with icodextrin replace two short dwells with glucose?

Due to the slower dissipation of the osmotic gradient, icodextrin-based solutions, compared to glucose-based solutions, can improve water removal. We investigated scenarios where one icodextrin-based long dwell (Extraneal) replaced two glucose-based exchanges. The three-pore model with icodextrin hydrolysis was used for numerical simulations of a single exchange to investigate the impact of different peritoneal dialysis schedules on fluid and solute removal in patients with different peritoneal solute transfer rates (PSTRs). We evaluated water removal (ultrafiltration, UF), absorbed mass of glucose (AbsGluc) and carbohydrates (AbsCHO, for glucose and glucose polymers), ultrafiltration efficiency (UFE = UF/AbsCHO) per exchange, and specified dwell time, and removed solute mass for sodium (ReNa), urea (ReU), and creatinine (ReCr) for a single peritoneal exchange with 7.5% icodextrin (Extraneal®) and glucose-based solutions (1.36% and 2.27%) and various dwell durations in patients with fast and average PSTRs. Introducing 7.5% icodextrin for the long dwell to replace one of three or four glucose-based exchanges per day leads to increased fluid and solute removal and higher UF efficiency for studied transport groups. Replacing two glucose-based exchanges with one icodextrin exchange provides higher or similar water removal and higher daily sodium removal but slightly lower daily removal of urea and creatinine, irrespective of the transport type present in the case of reference prescription with three and four daily exchanges. One 7.5% icodextrin can replace two glucose solutions. Unlike glucose-based solutions, it resulted only in minor differences between PSTR groups in terms of water and solute removal with UFE remaining stable up to 16h.

#1044 Quantitative analysis of dialytic protein loss with medium cut-off and high-flux membranes

Abstract Background and Aims Hemodialysis is an effective way for eliminating uremic retention products in patients with end-stage kidney disease. Medium cut-off membranes (MCO) were designed to enhance the dialytic removal of middle-sized molecules, such as beta-2 microglobulin (β2M). However, alongside these toxins, salutary proteins could also be lost. To better understand the spectrum of proteins cleared by MCO and high-flux (HF) dialyzers, we conducted qualitative and quantitative analysis of proteins in hemodialysis ultrafiltrate (UF). Method We established an ex vivo hemodialysis simulation system by using two Fresenius 2008T machines to concurrently dialyze a 2.5-liter human plasma reservoir for simultaneous testing of two dialyzers. We compared three dialyzers, including two HF dialyzers (Fresenius Medical Care Optiflux F180NR and FX CorAL 80), and an MCO membrane (Baxter Theranova 400; TH) (Fig. 1A). The blood flow rate was 400 mL/min, the dialysate flow rate was zero, and the ultrafiltration flow rate was 13 mL/min. UF samples were collected every 10 minutes from the UF line. Upon experiment completion at one-hour, residual filtrate was collected from the dialysate compartment. All samples were stored at −80°C until analysis. In total we conducted six dialysis simulations, each involving a concurrently tested dialyzer pair (Fig. 1B). UF samples underwent protein analysis (Bradford protein assay), albumin and creatinine measurement (Horiba® Pentra C400), liquid chromatography tandem mass spectrometry (LC-MS/MS)-based proteomics (Agilent® Q-TOF 6546), and immune-based protein assay (Luminex® Magpix). We analyzed the average of four sets of data obtained from the same dialyzer at the same time point. Results The loss of total protein and albumin was significantly greater with TH compared to the two HF dialyzers (Fig. 1C). Creatinine removal was similar across all dialyzers (Fig. 1D). The overall protein loss through F180NR and CorAL was comparable, while the protein loss through TH was up to 14-fold higher (811.7 ± 149.5 mg; Fig. 1E). Similar trends were observed for albumin. Albumin comprised 62% of the protein content in UF from TH, whereas it accounts for approximately 30% for HF dialyzers. We next employed label-free LC-MS and LC-MS/MS to identify and quantify proteins in 12 UF samples collected at the 20-minute point. Using Spectrum Mill software, we identified 244 proteins in the UF, 113 were accurately semi-quantified. The protein intensity ratios of TH-to- F180NR, TH-to-CorAL, and CorAL-to-F180NR for these 113 proteins are presented in Fig. 2A-C. Each gray dot on the plot corresponds to a specific protein. In line with the total protein and albumin quantification, MS proteomics analysis consistently revealed a greater loss of every identified protein by TH compared to both HF dialyzers. The median protein intensity ratio of TH-to-F180NR and TH-to-CorAL was 9.14 and 8.25, respectively. Importantly, TH not only removed middle-molecules such as β2M, but also showed a higher loss of salutary proteins. For instance, our data indicate a 9- to 16-fold difference in the level of albumin, haptoglobin, and vitamin D-binding protein between TH and HF dialyzers. Protein loss did not differ between F180NR and CorAL. To validate the accuracy of the MS quantification, we quantified seven proteins using immune-based assays in all UF samples at the 20-minute point. The result revealed a strong consistency between MS data and other methods (Fig. 2D). Conclusion We established an ex vivo system to concurrently test two dialyzers and implemented a robust proteomics workflow for a direct comparison of protein loss in the UF. Our data comprehensively and consistently indicate a greater extent of protein loss with MCO compared to HF, including the loss of salutary proteins. Further research is warranted to explore the clinical consequences of the enhanced loss of salutary proteins.

Biomass-based mixed matrix membrane adsorbers for removal of creatinine in dialysate fluid

Dialysate fluid is a vital component in hemodialysis therapy. Processing and reusing spent dialysate in hemodialysis significantly reduces costs and produces environmentally friendly hemodialysis. In this research, mixed matrix membrane adsorbers (MMMAs), which have the potential to recycle spent dialysate, have been developed. MMMA is composed of cellulose acetate (CA)-based polymers synthesized from cellulose isolated from oil palm empty fruit bunches (OPEFB) and integrated with silica (Si) bio-adsorbent from rice husk ash waste. The membrane was cast using the phase inversion method to form MMMAs CA-Si. The MMMAs CA-Si has a porous structure with evenly distributed silica particles. The pristine CA membranes had swelling and porosity degrees of 38.89 % and 21.23 %, while the MMMAs CA-Si had swelling and porosity degrees of 41.43 % and 27.81 %, respectively. The pristine CA membrane had a clean water flux of 86.86 L/m2h, while the MMMAs CA-Si membrane had a 96.25 L/m2h clean water flux. The MMMAs CA-Si has a tensile strength of 15.89 (Kgf/mm2) and an elongation of 14.01 %. The pristine CA membrane had a creatinine adsorption capacity of 2.8 mg/g, while the CA-Si MMMAs membrane had a maximum adsorption capacity of 9.98 mg/g. The maximum adsorption capacity (qm) is 9.98 mg/g MMMAs, equivalent to 24.95 mg creatinine/g silica in MMMAs and the dissociation constant (Kd) value is 1.91 mg/L. Creatinine can be removed from the dialysate through a continuous flow dialysis process using MMMAs CA-Si with a total removal of 10.48 mg/g or above 66.45 %. Creatinine can also be filtered by cross-flow circulation, and the total creatinine removal is above 81.0 %. MMMAs CA-Si can be an alternative separation medium to remove creatinine in the dialysate.

Heparin-Mimetic Chitooligosaccharides-Based Monoliths Obtained from C/W Emulsions: Hemocompatibility and Toxin Removal Ability.

Hemoperfusion (HP) is one of the most prominent therapies for treating uremia, hyperbilirubinemia, and acute drug toxicity. The comprehensive performance of currently used porous HP adsorbents needs to be improved due to the impediment to their synthesis strategy. Herein, green carbon dioxide-in-water high internal phase emulsions (C/W HIPEs) were utilized and emulsified with poly(vinyl alcohol) (PVA) for the formation of a heparin-mimetic chitosan oligosaccharides/poly(acrylamide-co-sodium 4-styrenesulfonate) [COS/P(AM-co-SSS)] monolith, which exhibited good mechanical properties, stable swelling performance, hydrophilic properties, anticoagulant effect, and low hemolysis. It showed a strong toxin adsorption capacity (415.2 mg/g for creatinine, 199.3 mg/g for urea, 279.5 mg/g for bilirubin, and 160 mg/g for tetracycline). The adsorption process of porous COS/P(AM-co-SSS) followed the pseudo-second-order kinetic and Langmuir isotherm models. Moreover, the porous materials had a strong electrostatic force on creatinine. The removal of creatinine by simulated in vitro blood perfusion was 80.2% within 30 min. This work provides a green preparation strategy for developing novel HP materials, highlighting their potential application value in blood and environmental purification.

Electrospun polyacrylonitrile/halloysite nanofibrous membranes for creatinine removal from kidney failure patients

Innovative hemodialysis membranes are essential for hemodialysis process, the vital clinical treatment for patients with kidney failure. In the present study, for the first time halloysite nanotubes (Hal) were applied to adsorb creatinine through molecular sieve mechanism. Firstly, calcination process performed to improve the affinity of Hal for creatinine. Afterwards, eight different composite polyacrylonitrile (PAN) nanofibrous membranes containing two types of Hal including raw Hal (RHAL) and calcined Hal (CHAL) were developed via an electrospinning device (10, 20, 30 and 40 wt%). Morphological analysis revealed that, with low contents of Hal (10 and 20 wt%), the structural integrity of nanofibers was maintained. However, with the high contents of Hal (30 and 40 wt%), structural integrity of nanofibers was affected and conical beads were formed. The mechanical properties and hydrophilicities of the composite PAN based membranes were higher than pure PAN based membrane and improved by increasing Hal contents up to 20 wt% and then reduced. Therefore, among the composite PAN based membranes, the membranes loaded with 10 and 20 wt% of Hal were selected for further evaluations. Adsorption studies showed that the composite PAN based membrane loaded with 20 wt% of CHAL had best performance with >70% of creatinine removal. The MTT assay also presented; the highest cell viability about 90% for the same membrane. Blood compatibility of the membranes for both bovine serum albumin (BSA) surface adsorption and platelet adhesion revealed that the composite PAN membranes were significantly more blood compatible than the polyethersulfone (PES) commercial and pure PAN based membranes. As a result, composite PAN based membrane loaded with 20 wt% of CHAL which combines adsorption and traditional mechanism, seems promising for hemodialysis membranes.

#3345 EFFECTS OF CONDITIONED MEDIUMS COLLECTED FROM 2D OR 3D CULTURED MSCS ON KIDNEY FUNCTIONS OF RATS WITH AUTOIMMUNE DIABETES INDUCED WITH STREPTOZOCIN

Abstract Background and Aims The main mechanism of therapeutic action of mesenchymal stem cells (MSCs) could be resulted from their secretome content rather than their direct differentiation into damaged cells [1, 2]. Preconditioning of MSCs with different strategies like culturing in 3 dimensional (3D) culture scaffolds could improve their therapeutic potential [1]. Based on our previous study [1] in which the concentrations of total protein and specifically VEGF and IL-4 in conditioned mediums (CMs) collected from MSCs cultured in 3D culture conditions were increased compared to one of 2D, the aim of this study is comparative analysis of effects of CMs obtained from MSCs incubated under 2D and 3D culture conditions on kidney functions of rats with autoimmune type I diabetes (aT1D) induced with streptozocin (STZ). Method Isolation and characterization of the umbilical cord MSCs and the following analysis of concentrations of total protein and paracrine factors in the 2D-CMs and 3D-CMs were performed as it was mentioned [1]. Sprague-Dawley rats were treated with 20 mg/kg STZ for 5 consecutive days to induce T1D and 12 doses of CMs were intraperitoneally introduced for 4 weeks in accordance with the timeline defined in Figure 1. Therapeutic effects of CMs were comparatively investigated by biochemical, physical, histopathological and immunohistochemical analysis. Results At the end of the 2nd week, urinary albumin/creatinine (u-Alb/Cr) ratio and creatinine removal rate (Crr) of diabetes were significantly aggravated compared to control group (p = 0,0001 and p = 0,13 respectively). At the end of the 7th week, u-Alb/Cr ratios of both treatment groups were significantly improved compared to one of diabetes group (p = 0,029 vs p = 0,002). There was no statistical difference among all groups for Crr values. In the post treatment period u-Alb/Cr ratio was exacerbated (p = 0,014) while Crr value was not changed compared to pre-treatment period (p = 0,713). There was no statistical change between the pre- and post-treatment values of u-Alb/Cr ratio and Crr for both treatment groups. Renal mass index of control group was lower than the ones of experimental groups, while weight percent change from pre- to post-treatment period of control group was statistically higher than the ones of experimental groups (p = 0,0001). However, there was no statistical difference for both parameters among the experimental groups (Figure 2). Histopathological evaluations showed that cortical tubular damage (CTD) was significantly ameliorated in only D+3D-CM group compared to diabetes group (p = 0,012), while there was no statistical change in glomerular fibrosis in both treatment groups (Figure 3.1 and 3.2 respectively). Immunohistochemical analysis indicated that nephrin expression was insignificantly increased in both treatment groups compared to diabetes group (Figure 3.3). Preliminary evaluation of thicknesses of glomerular basal membrane and pedicel with transmission electron microscopy (TEM) showed no clear difference among all the groups (Figure 4). Conclusion CM obtained from MSCs in 3D culture conditions could partially ameliorate kidney functions of aT1D by improving CTD and expression of nephrin which is crucial for the integrity of glomerular filtration barrier.

Performant removal of creatinine using few-layer-graphene/alginate beads as a kidney filter

Reduction of renal function, such as creatinine adsorption is one of the most common and dangerous diseases. Dedicated to this issue, developing high-performance, sustainable, and bio-compatible adsorbing materials is still challenging. Herein, barium alginate (BA) and BA containing few-layer graphene (FLG/BA) beads were synthesized in water from sodium alginate, also acting as bio-surfactant in in-situ exfoliation of graphite to FLG. The physicochemical characteristics of the beads demonstrated an excess of barium chloride used as a cross-linker. The efficiency and sorption capacity (Qe) of creatinine removal increase with processing duration reaching 82.1, 99.5 %, and 68.4, 82.9 mg·g−1 for BA and FLG/BA, respectively. The thermodynamic parameters detect the enthalpy change (ΔH°) of about −24.29 and −36.11 kJ·mol−1 and the entropy change (ΔS°) of around −69.24 and −79.46 J·mol−1 K−1 for BA and FLG/BA, respectively. During the reusability test, the removal efficiency decreases from the optimal first cycle to 69.1 and to 88.3 % in the sixth cycle for BA and FLG/BA, revealing superior stability of FLG/BA. The MD calculations confirm a higher adsorption capacity of FLG/BA composite compared to BA alone, clearly confirming a strong structure-property relation.

Experimental design for combined abatement of organic compounds present in urine

AbstractOrganic compounds contained in urine, such as urea and creatinine, can compete with pharmaceuticals for the electro‐generated oxidants during electrochemical treatment. In addition, urine has a large amount of chloride ions, creating opportunities to produce chlorine and aqueous‐free chlorine species via electrolysis. The aim of the present study is to analyze artificial urine as a supporting electrolyte, while studying the removal of the organic components present (urea and creatinine) by employing an experimental design approach. A 2³ factorial design was employed to evaluate the efficiency of the photo‐assisted sonoelectrochemical (EC/UV/US) process. Operating conditions were optimized using response surface methodology (MRS), namely: 11.44 mL min−1 flow, 1.940 A at 160 min. The pH was analyzed and a predominance of HOCl (pH < 7.0) can be observed. Response surface methodology was used to investigate the effects and interactions of flow rate, time, and current to track the removal efficiency of organic compounds contained in artificial urine (TOC, creatinine, and urea). Over prolonged electrolysis, the EC/US/UV process achieved removal of TOC (25.7%), creatinine (68.2%), and urea (33.3%), due to the large contribution of highly reactive radical species (•OH, •Cl, ClO−).

Synthesis of an IRMOF-1@SiO2 Core-Shell and Amino-Functionalization with APTES for the Adsorption of Urea and Creatinine Using a Fixed-Bed Column Study.

Kidney dysfunction is a clinical disease that disables the kidneys to remove the waste products and uremic toxins from the circulation and may lead to fatal kidney failure. Hemodialysis is advantageous in this circumstance since it prevents the accumulation of waste products in the body and facilitates the removal of uremic toxins. However, hemodialysis cannot entirely remove some uremic toxins, such as urea and creatinine. In this paper, a high-performance fixed-bed column for urea and creatinine removal was offered. As a result, a MOF layer was built on SiO2, which was then amino-functionalized using APTES. Numerous assays were used to characterize the final adsorbent. The adsorption of urea and creatinine was evaluated in batch and continuous conditions. Thus, it was demonstrated that the adsorption behavior of A(0.2)-IRMOF-1@SiO2 followed the Langmuir isotherm, and it exhibited the maximum adsorption capacity. The batch experiment determined that urea and creatinine had an adsorption capacity of 1325.73 and 625.00 mg·g-1, respectively. The adsorption capacity was increased, which was due to the presence of amino groups (APTES) on the MOF surface. The continuous operation was evaluated using the A(0.2)-IRMOF-1@SiO2 fixed-bed column. Thomas and Nelson's models were examined to achieve a better understanding of the adsorption behaviors. The A(0.2)-IRMOF-1@SiO2 fixed-bed column successfully removed 92.57% of urea and 80.47% of creatinine. The separation factor for urea in comparison to creatinine was 2.40 in the A(0.2)-IRMOF-1@SiO2 fixed-bed column.

Fabrication and characterization of novel PES-based nanocomposite hollow fiber membranes for the hemodialysis process

In the hemodialysis process, membrane filtration is used to clean blood. Urea and creatinine are two significant substances that should be removed from the blood during hemodialysis, which takes a great deal of time. To decrease the hemodialysis process time, in this study, we fabricated novel polyethersulfone nanocomposite hollow fiber membranes with silica and amine-modified silica nanoparticles via the non-solvent induced phase separation (NIPS) method. Membranes have been evaluated in a membrane contactor system by two modes of contact with fresh sweeper fluid (retentate process) and recycled sweeper fluid (circulated process) to remove urea and creatinine from a synthetic blood-like solution. Fourier transform infrared (FTIR) was carried out along with pure water flux, contact angle, mechanical strength, field emission electron microscope test (FESEM), and X-ray diffraction (EDX) to characterize the synthesized nanoparticles and fabricated membranes. The results revealed that modification of membranes by silica and amine-modified silica nanoparticles increased the urea and creatinine removal rate from the feed as the modified membranes’ separation mechanisms were adsorption and diffusion. Furthermore, removal of urea and creatinine were higher in the retentate process than the circulated process. The membrane samples containing 1.5% amine-modified silica nanoparticles had the highest urea and creatinine removal rate compared to the other modified membranes containing fewer or higher amine-modified silica and/or silica nanoparticles in the both retentate and circulated processes. The adsorption kinetics showed that the adsorption of urea and creatinine on the surface of the silica and amine-modified silica nanoparticles were consistent with the pseudo-second kinetic model, meaning rapid and possibly irreversible adsorption.

Double filtration plasmapheresis for children with different types of critical kidney diseases: a single-center retrospective cohort study.

Double filtration plasmapheresis (DFPP) was initially used to facilitate the conduction of ABO-incompatible renal transplantation. The applicability of DFPP has recently expanded to cover the removal of various antibodies in adults with immune-mediated diseases. However, DFPP is seldom used in children, with few reports addressing its efficacy and safety in this population. This study aimed to explore the efficacy and adverse effects of DFPP for pediatric patients with renal indications. Children who received DFPP between December 2017 and December 2020 at Tongji Hospital were retrospectively studied, and sub-grouped for analysis according to the types of disease. All children received 3 to 6 DFPP sessions within 2 to 3 weeks, and were assessed for clinical outcomes according to glomerular filtration rate, proteinuria and extra-renal symptoms. Pre- and post-DFPP plasma were collected to measure the levels of pathogenic autoantibodies, immunoglobulins, fibrinogen, albumin, calcium, etc. In-hospital complications were also recorded. Totally there were 10 children receiving 44 sessions of DFPP, including 2 males and 8 females, with a median age of 11.2 years old (5-13 years) and a median weight of 42.1 kg (20-59 kg). Five patients were treated for systemic lupus erythematosus (SLE), three patients for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), one for C3 glomerulopathy and one for ABO-incompatible renal transplantation. Plasma autoantibodies decreased substantially by 93% and 89% in those with SLE and AAV after the last session, respectively. Complete or partial responses were achieved in 80%, 33.3%, 100% and 100% of patients with SLE, AAV, C3 glomerulopathy, and ABO-incompatible renal transplantation, respectively. The proportion of cumulative IgG, fibrinogen, and albumin removal at the end of the last sessions were 58.8%, 67.69%, and 14.05% respectively. The removal of calcium, potassium and creatinine were not statistically significant. A few episodes (4.55%) of hypotension were observed when fresh frozen plasma was used as the replacement fluid, and no bleeding nor severe anaphylaxis was noted. The efficacy and safety of DFPP treatment in children with SLE, AAV, C3 glomerulopathy and ABO-incompatible renal transplantation were described in the present study. DFPP is proven to be a safe apheresis method for children weighing more than 20 kg.

Urine volume as an estimator of residual renal clearance and urinary removal of solutes in patients undergoing peritoneal dialysis

In non-anuric patients undergoing peritoneal dialysis (PD), residual kidney function (RKF) is a main contributor to fluid and solute removal and an independent predictor of survival. We investigated if urine volume could be used to estimate renal clearances and removal of urea, creatinine, and phosphorus in PD patients. The observational, cross-sectional study included 93 non-anuric prevalent PD patients undergoing continuous ambulatory PD (CAPD; n = 34) or automated PD (APD; n = 59). Concentrations of urea, creatinine and phosphorus in serum and in 24-h collections of urine volume were measured to calculate weekly residual renal clearance (L/week) and removed solute mass (g/week). Median [interquartile range], 24-h urine output was 560 [330–950] mL and measured GFR (the mean of creatinine and urea clearances) was 3.24 [1.47–5.67] mL/min. For urea, creatinine and phosphorus, residual renal clearance was 20.60 [11.49–35.79], 43.02 [19.13–75.48] and 17.50 [8.34–33.58] L/week, respectively, with no significant differences between CAPD and APD. Urine volume correlated positively with removed solute masses (rho = 0.82, 0.67 and 0.74) and with weekly residual renal clearances (rho = 0.77, 0.62 and 0.72 for urea, creatinine, and phosphorus, respectively, all p < 0.001). Residual renal clearances and urinary mass removal rates for urea, creatinine, and phosphorus correlate strongly with 24-h urine volume suggesting that urine volume could serve as an estimator of typical values of residual solute removal indices in PD patients.

Intradialytic Protein Ingestion and Exercise do Not Compromise Uremic Toxin Removal Throughout Hemodialysis

Dietary protein and physical activity interventions are increasingly implemented during hemodialysis to support muscle maintenance in patients with end-stage renal disease (ESRD). Although muscle maintenance is important, adequate removal of uremic toxins throughout hemodialysis is the primary concern for patients. It remains to be established whether intradialytic protein ingestion and/or exercise modulate uremic toxin removal during hemodialysis. We recruited 10 patients with ESRD (age: 65±16y, BMI: 24.2±4.8kg/m2) on chronic hemodialysis treatment to participate in this randomized cross-over trial. During hemodialysis, patients were assigned to ingest 40g protein or a nonprotein placebo both at rest (protein [PRO] and placebo [PLA], respectively) and following 30min of exercise (PRO+exercise [EX] and PLA+EX, respectively). Blood and spent dialysate samples were collected throughout hemodialysis to assess reduction ratios and removal of urea, creatinine, phosphate, cystatin C, and indoxyl sulfate. The reduction ratios of urea and indoxyl sulfate were higher during PLA (76±6% and 46±9%, respectively) and PLA+EX interventions (77±5% and 45±10%, respectively) when compared to PRO (72±4% and 40±8%, respectively) and PRO+EX interventions (73±4% and 43±7%, respectively; protein effect: P=.001 and P=.023, respectively; exercise effect: P=.25 and P=.52, respectively). Nonetheless, protein ingestion resulted in greater urea removal (P=.046) during hemodialysis. Reduction ratios and removal of creatinine, phosphate, and cystatin C during hemodialysis did not differ following intradialytic protein ingestion or exercise (protein effect: P>.05; exercise effect: P>.05). Urea, creatinine, and phosphate removal were greater throughout the period with intradialytic exercise during PLA+EX and PRO+EX interventions when compared to the same period during PLA and PRO interventions (exercise effect: P=.034, P=.039, and P=.022, respectively). The removal of uremic toxins is not compromised by protein feeding and/or exercise implementation during hemodialysis in patients with ESRD.

Non-woven fabrics based on Nylon 6/carbon black-graphene nanoplatelets obtained by melt-blowing for adsorption of urea, uric acid and creatinine

This is the first study to successfully manufacture nonwoven fabrics capable to absorb uremic toxins, based on Nylon 6 incorporating graphene nanoplatelets modified with amino groups and carbon black modified with carboxylic groups by melt-blowing. The non-woven fabrics presented good mechanical properties, specifically the % elongation increased from 77 % of pure Nylon 6 to 98.4 % with the Nylon-6/GNP/CB 0.50% sample. The non-woven fabrics showed a greater efficiency in the removal of creatinine and uric acid with 81 and 88%, respectively with the same sample. In addition, 90% of urea was removed during 3 h with 10 min after simulating a dialysis for 4 h, with the 0.25% Nylon-6/GNP/CB non-woven fabric. This method can be used to manufacture a new membrane for filtration and separation of uremic toxins from the blood stream.

Flexible Zr-MOF anchored polymer nanofiber membrane for efficient removal of creatinine in uremic toxins

High-performance and low-cost hemodialysis membranes are urgently needed by patients suffering from end-stage renal disease. Here, we designed a flexible multifunctional Zr-MOF anchored polyacrylonitrile (PAN) nanofiber membrane (UAPNFM), which has good adsorption, dialysis, and regeneration ability. A novel adhesive layer modification method was used to make UIO-66-(COOH) 2 nanocrystals grow in-situ on the composite nanofibers. The UIO-66-(COOH) 2 nanocrystals were uniformly and stably anchored on the nanofibers with the content of 54.99 wt%. The obtained UAPNFM has the capability to effectively remove uremic toxins with excellent retain protein rate. The Langmuir isotherm and pseudo-second-order kinetic model can be applied to better describe the adsorption process. The maximum adsorption capacity of UAPNFM for creatinine reached 168.63 mg/g. After 4 h of simulate dialysis, the clearance rate of creatinine was 82.48% and the protein retention rate of bovine serum albumin (BSA) by the UAPNFM was 93.09%. In addition, after four cycles, the removal efficiency for creatinine still remained at 82.31%. The results show that the UAPNFM has good regenerability. Moreover, the composite nanofiber membrane exhibited satisfactory blood compatibility. Therefore, this unique flexible Zr-MOF anchored polymer composite nanofiber membrane with an outstanding creatinine removal performance provides a new opportunity for cost reduction for clinical hemodialysis. • A flexible multifunctional Zr-MOF anchored nanofiber membrane is prepared. • The UAPNFM has excellent blood compatibility. • The UAPNFM shows high adsorption capacity towards creatinine. • The UAPNFM could effectively remove uremic toxins with excellent retain protein rate. • The UAPNFM has great application prospect in low-cost clinical blood purification.

Dual-layer hollow fibre haemodialysis membrane for effective uremic toxins removal with minimal blood-bacteria contamination

Bacterial endotoxin contamination in dialysate may pass through haemodialysis membrane and cause a silent chronic microinflammation to kidney patients. Dual-layer hollow fibre (DLHF) membranes with dual function, biocompatible adsorptive and antibacterial effects were developed to solve the problem of incompatible membrane and endotoxin contamination. All membranes were fabricated via the co-extrusion dry-wet phase inversion technique. In this study, silica/α-mangostin nanoparticle was incorporated into the inner layer of membrane to enhance the biocompatibility of the membrane while maintaining its adsorption capacity. Activated carbon (AC) was incorporated in the outer layer of membrane for improved antibacterial property. The DLHF membranes were characterised based on its morphology and surface hydrophilicity. The performance of the DLHF membranes was evaluated in terms of permeability, urea, and creatinine removal capabilities, bovine serum albumin (BSA) rejection and antibacterial properties. The dense and small pore size on the outer layer of AC created a smoother surface for the DLHF membrane. The BSA rejection of the DLHF membranes was enhanced by 6–8% compared to that of unmodified single layer hollow fibre membrane. Silica/α-mangostin nanoparticle in the inner layer of membrane enhanced the removal of urea and creatinine by chemisorption. Result also showed that the incorporation of AC in the outer layer of DLHF membrane successfully filtered bacteria by bacteria entrapment. DLHF membrane with the combination of silica/α-mangostin nanoparticle in the inner layer and AC in the outer layer possessed the higher bacteria inhibition into blood compartment against Escherichia coli and Staphylococcus aureus, with removal rate of 68% and 75%, respectively, and better urea and creatinine removal by 60.57% and 75.18%, respectively, compared to single-layer PSf based membrane. The development of co-adsorptive biocompatible DLHF membrane can play an important role in improvement of kidney patient life.

Magnetic chitosan membrane as an effective analytical tool for adsorptive removal of creatinine from biological samples

Creatinine, a final product of metabolism released in the blood and removed by kidneys. The improper functioning of kidneys causes its higher accumulation in blood. In this study, a facile strategy was designed for artificial kidneys by using magnetic chitosan membrane. The membrane was synthesized by phase conversion process. The synthesized membrane was characterized by fourier transform infrared spectroscopy, elemental diffraction spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Different factors were optimized for creatinine removal by membrane such as concentrations of creatinine, pH, time, interfering species. The linear response was obtained in the concentration range from 10 to 70 µM of creatinine. The results showed the limit of detection 7.33 µM and the limit of quantification 22.82 µM at optimized conditions. The magnetic chitosan membrane facilitates the development of the ecofriendly and cost effective method for the removal of biological toxins from real samples.

Mixed Matrix Membranes Adsorbers (MMMAs) for the Removal of Uremic Toxins from Dialysate.

We developed Mixed Matrix Membrane Adsorbers (MMMAs) formed by cellulose acetate and various sorbent particles (activated carbon, zeolites ZSM-5 and clinoptilolite) for the removal of urea, creatinine and uric acid from aqueous solutions, to be used in the regeneration of spent dialysate water from Hemodialysis (HD). This process would allow reducing the disproportionate amount of water consumed and permits the development of closed-loop HD devices, such as wearable artificial kidneys. The strategy of MMMAs is to combine the high permeability of porous membranes with the toxin-capturing ability of embedded particles. The water permeability of the MMMAs ranges between 600 and 1500 L/(h m2 bar). The adsorption of urea, the limiting toxin, can be improved of about nine times with respect to the pure cellulose acetate membrane. Flow experiments demonstrate the feasibility of the process in a real HD therapy session.

Electrodegradation of cyclophosphamide in artificial urine by combined methods

ABSTRACT The degradation of the chemotherapeutic drug cyclophosphamide in artificial urine was evaluated by Electrochemical Advanced Oxidation Processes (EAOP). The system consisted of an electrochemical flow reactor with a commercial DSA® electrode (nominal composition Ti / Ru0,3Ti0,7O2) and Ti-mesh cathode. In order to assess the best parameters, the effect of current density, time and flow rate were analyzed using an initial 23 factorial design. The chosen response variable was the energy efficiency to produce free chlorine species (HClO/ClO−). After obtaining the most significant factors, the Central Composite Design (CCD) was performed, where the optimum conditions were determined for the current density range (11.714 mA cm−2 and 66.57 mA cm−2), flow rate (31.33 mL min−1) and time range (19 and 37 min). Under an optimized condition, the efficiency of other combined methods (photo-assisted electrochemical, photochemical, sonoelectrochemical and photo-assisted sonoelectrochemical) was evaluated. The efficiency of degradation processes was determined by removal of Chemical Oxygen Demand (COD), creatinine and urea. Analysis by HPLC demonstrates that the cyclophosphamide was substantially removed during the treatment process of ∼77%. Based on these results, it can be observed that the coupling between electrochemical and photochemical processes is a promising alternative for the treatment of this effluent, as a marked reduction of organic matter is observed (63, 94% of creatinine, 29.62% of urea, 39.1% of TOC) and a low treatment cost ratio.

Enhanced adsorption and biocompatibility of polysulfone hollow fibre membrane via the addition of silica/alpha-mangostin hybrid nanoparticle for uremic toxins removal

In this study, a highly biocompatible adsorptive membrane is developed for haemodialysis application. Silica/α-mangostin hybrid nanoparticle was incorporated into polysulfone (PSf) based membrane to enhance the biocompatibility and the adsorption capacity of the membrane. The PSf based membranes were fabricated via dry-wet phase inversion technique and characterised based on scanning electron microscopy and contact angle measurement. The effects of silica/α-mangostin nanoparticle incorporation into PSf membrane were evaluated in terms of permeability, p-cresol adsorption capacity, urea, and creatinine removal capabilities, bovine serum albumin rejection and p-cresol dynamic adsorption. The biocompatibility assessment was done based on platelet adhesion, antioxidant properties, and complement activation of the membrane. The incorporation of the nanoparticle into PSf based membrane helped to smoothen the surface of the membrane and enhanced its hydrophilicity of the membrane by 12.54%. The presence of silica/α-mangostin in the membrane enhanced the adsorption capacity of the membrane by 20.92% with adsorption capacity of 55.64 mg/g at 500 mg/L initial concentration. The modified PSf membrane had also successfully improved the biocompatibility of the membrane by enhancing the scavenging activity of hydrogen peroxide and nitrogen oxide by 61.8% and 36%, respectively and inhibited the formation of C5a by 27.27%. The developed biocompatible PSf based adsorptive membrane has a good potential to be used for haemodialysis application.