Urea removal strategies for dialysate regeneration in a wearable artificial kidney

Gelder, Maaike K. van; Jong, Jacobus A.W.; Folkertsma, Laura; Guo, Yong; Bluchel, Christian G.; Verhaar, Marianne C.; Odijk, Mathieu; Nostrum, Cornelus F. van; Hennink, Wim E.; Gerritsen, Karin G.F.

doi:10.1016/j.biomaterials.2019.119735

Cited by 71 publications

(59 citation statements)

References 154 publications

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“…To improve the quality of life of dialysis patients, wearable artificial kidney devices are being developed which use a small volume of dialysate (preferably <0.5 L) that is continuously regenerated by a purification unit and re‐used in a closed loop system 2–4. Removal of urea from dialysate is a major challenge in the realization of such a wearable dialysis device,5,6 since urea has low reactivity and high aqueous solubility while it is the metabolite with the highest daily molar production (240–470 mmol day −1 ) 7,8. It has been estimated that a urea clearance of 25–49 mL min −1 is needed in a 8‐h dialysis session to keep the urea concentration below 20 m m .…”

Section: Introductionmentioning

confidence: 99%

“…It has been estimated that a urea clearance of 25–49 mL min −1 is needed in a 8‐h dialysis session to keep the urea concentration below 20 m m . [6] Several strategies for urea removal from dialysate have been explored,6 including enzymatic hydrolysis,9,10 electro‐oxidation,11 and adsorption of urea 12–16. However, each of these strategies has drawbacks that do not allow reduction of the dialysate volume to <0.5 L as required for a wearable device 6,17…”

Section: Introductionmentioning

confidence: 99%

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A Ninhydrin‐Type Urea Sorbent for the Development of a Wearable Artificial Kidney

Jong

Guo

Hazenbrink

et al. 2020

Macromolecular Bioscience

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The aim of this study is to develop polymeric chemisorbents with a high density of ninhydrin groups, able to covalently bind urea under physiological conditions and thus potentially suitable for use in a wearable artificial kidney. Macroporous beads are prepared by suspension polymerization of 5‐vinyl‐1‐indanone (vinylindanone) using a 90:10 (v/v) mixture of toluene and nitrobenzene as a porogen. The indanone groups are subsequently oxidized in a one‐step procedure into ninhydrin groups. Their urea absorption kinetics are evaluated under both static and dynamic conditions at 37 °C in simulated dialysate (urea in phosphate buffered saline). Under static conditions and at a 1:1 molar ratio of ninhydrin: urea the sorbent beads remove ≈0.6–0.7 mmol g−1 and under dynamic conditions and at a 2:1 molar excess of ninhydrin ≈0.6 mmol urea g−1 sorbent in 8 h at 37 °C, which is a step toward a wearable artificial kidney.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Ninhydrin‐Type Urea Sorbent for the Development of a Wearable Artificial Kidney

Jong

Guo

Hazenbrink

et al. 2020

Macromolecular Bioscience

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confidence: 99%

“…Currently, no efficient urea sorbent is available for application in a wearable artificial kidney[42]. As the affinity of urea for activated carbon is relatively low (0.1-0.2 mmol/g), a relatively large amount of activated carbon (1.2-4.7 kg) would be required to remove the daily urea production[42]. Htay et al report use of enzymatic hydrolysis of urea by urease for dialysate regeneration in a wearable artificial kidney for CFPD, a system of <2 kg using 3 cartridges and 3 exchanges of 2 L per day[5,19].Urea removal by urease was first applied in the REcirculation DialYsis (REDY) sorbent system in HD[8]51].…”

mentioning

confidence: 99%

“…Although a urease-based sorbent system may allow miniaturization of the system to wearable proportions, the technology is complex and has several disadvantages. Toxic ammonium is generated during hydrolysis of urea that must be removed almost completely from dialysate by zirconium phosphate (cation exchanger), that binds ammonium in exchange for sodium and hydrogen, risking sodium release into the patient and acid base disturbances, respectively[42]. In addition, zirconium phosphate binds calcium, magnesium and too much potassium which must be re-infused from a separate reservoir.…”

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confidence: 99%

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In vitro efficacy and safety of a system for sorbent-assisted peritoneal dialysis

Gelder

Ligabue

Giovanella

et al. 2020

American Journal of Physiology-Renal Physiology

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A system for sorbent-assisted peritoneal dialysis (SAPD) was designed to continuously recirculate dialysate via a tidal mode using a single lumen peritoneal catheter with regeneration of spent dialysate by means of sorbent technology. We hypothesize that SAPD treatment will maintain a high plasma-to-dialysate concentration gradient and increase the mass transfer area coefficient of solutes. Thereby, the SAPD system may enhance clearance while reducing the number of exchanges. Application is envisaged at night as a bedside device (12 kg, nighttime system). A wearable system (2.0 kg, daytime system) may further enhance clearance during the day. Urea, creatinine, and phosphate removal were studied with the daytime and nighttime system ( n = 3 per system) by recirculating 2 liters of spent peritoneal dialysate via a tidal mode (mean flow rate: 50 and 100 mL/min, respectively) for 8 h in vitro. Time-averaged plasma clearance over 24 h was modeled assuming one 2 liter exchange/day, an increase in mass transfer area coefficient, and 0.9 liters ultrafiltration/day. Urea, creatinine, and phosphate removal was 33.2 ± 4.1, 5.3 ± 0.5, and 6.2 ± 1.8 mmol, respectively, with the daytime system and 204 ± 28, 10.3 ± 2.4, and 11.4 ± 2.1 mmol, respectively, with the nighttime system. Time-averaged plasma clearances of urea, creatinine and phosphate were 9.6 ± 1.1, 9.6 ± 1.7, and 7.0 ± 0.9 mL/min, respectively, with the nighttime system and 10.8 ± 1.1, 13.4 ± 1.8, and 9.7 ± 1.6 mL/min, respectively, with the daytime and nighttime system. SAPD treatment may improve removal of uremic toxins compared with conventional peritoneal dialysis, provided that peritoneal mass transport will increase.

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Ammonia measurement in human breath of subjects with Helicobacter pylori using photoacoustic spectroscopy

Popa,

Petrus,

Bratu

2024

Journal of Biophotonics

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Helicobacter pylori (H. pylori) is a type of bacteria that infects the stomach. The detection of H. pylori is an essential part of current clinical practices because this disease can cause peptic ulcers, chronic inflammation of the stomach lining but also stomach cancer. Helicobacter pylori has a naturally occurring enzyme that hydrolyzes urea into ammonium carbonate called urease. Many methods exist for the detection of H. pylori infection, but an innovative approach is to detect the ammonia in the breath (ABT, Ammonia Breath Test). In this research study, using photoacoustic spectroscopy method, the ammonia concentration in the breathing zone of people with H. pylori were measured and were compared with ammonia concentration from the respiration of healthy people. From the ABT determinations of this study, the ammonia was established to be increased with 498 ppb at people with H. pylori when we compare with ABT of healthy people.

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Urea removal strategies for dialysate regeneration in a wearable artificial kidney

Cited by 71 publications

References 154 publications

A Ninhydrin‐Type Urea Sorbent for the Development of a Wearable Artificial Kidney

A Ninhydrin‐Type Urea Sorbent for the Development of a Wearable Artificial Kidney

In vitro efficacy and safety of a system for sorbent-assisted peritoneal dialysis

Ammonia measurement in human breath of subjects with Helicobacter pylori using photoacoustic spectroscopy

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