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Butani L, Haddad M, Joseph M. Tidal continuous cycling peritoneal dialysis in children. Pediatr Nephrol 2023; 38:3955-3961. [PMID: 36780006 PMCID: PMC10584695 DOI: 10.1007/s00467-023-05898-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 02/14/2023]
Abstract
About 10% of all home peritoneal dialysis regimens in children with chronic kidney disease stage 5 are reported to involve some form of a tidal peritoneal dialysis (TPD) prescription. Despite this, there remain several gaps in how pediatric nephrologists approach the use of TPD. This stems from a combination of factors such as the confusing technical terminology pertaining to TPD, seemingly conflicting data on the risks, benefits, and indications for TPD, and lastly, limited published guidelines on the practical aspects of how to write a TPD prescription, based on the indication, in children. Our educational review, using evidence-based data, attempts to bridge this gap and provide an easy-to-use guide on the key practical aspects of TPD in children.
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Affiliation(s)
- Lavjay Butani
- Division of Pediatric Nephrology, Department of Pediatrics, University of California, Davis, 2516 Stockton Blvd, Room 348, Sacramento, CA, 95817, USA.
| | - Maha Haddad
- Division of Pediatric Nephrology, Department of Pediatrics, University of California, Davis, 2516 Stockton Blvd, Room 348, Sacramento, CA, 95817, USA
| | - Mark Joseph
- Division of Pediatric Nephrology, Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
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Segeroth M, Wachsmuth L, Gagel M, Albers F, Hess A, Faber C. Disentangling the impact of cerebrospinal fluid formation and neuronal activity on solute clearance from the brain. Fluids Barriers CNS 2023; 20:43. [PMID: 37316849 DOI: 10.1186/s12987-023-00443-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/18/2023] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND Despite recent attention, pathways and mechanisms of fluid transposition in the brain are still a matter of intense discussion and driving forces underlying waste clearance in the brain remain elusive. Consensus exists that net solute transport is a prerequisite for efficient clearance. The individual impact of neuronal activity and cerebrospinal fluid (CSF) formation, which both vary with brain state and anesthesia, remain unclear. METHODS To separate conditions with high and low neuronal activity and high and low CSF formation, different anesthetic regimens in naive rat were established, using Isoflurane (ISO), Medetomidine (MED), acetazolamide or combinations thereof. With dynamic contrast-enhanced MRI, after application of low molecular weight contrast agent (CA) Gadobutrol to cisterna magna, tracer distribution was monitored as surrogate for solute clearance. Simultaneous fiber-based Ca2+-recordings informed about the state of neuronal activity under different anesthetic regimen. T2-weighted MRI and diffusion-weighted MRI (DWI) provided size of subarachnoidal space and aqueductal flow as surrogates for CSF formation. Finally, a pathway and mechanism-independent two-compartment model was introduced to provide a measure of efficiency for solute clearance from the brain. RESULTS Anatomical imaging, DWI and Ca2+-recordings confirmed that conditions with distinct levels of neuronal activity and CSF formation were achieved. A sleep-resembling condition, with reduced neuronal activity and enhanced CSF formation was achieved using ISO+MED and an awake-like condition with high neuronal activity using MED alone. CA distribution in the brain correlated with the rate of CSF formation. The cortical brain state had major influence on tracer diffusion. Under conditions with low neuronal activity, higher diffusivity suggested enlargement of extracellular space, facilitating a deeper permeation of solutes into brain parenchyma. Under conditions with high neuronal activity, diffusion of solutes into parenchyma was hindered and clearance along paravascular pathways facilitated. Exclusively based on the measured time signal curves, the two-compartment model provided net exchange ratios, which were significantly larger for the sleep-resembling condition than for the awake-like condition. CONCLUSIONS Efficiency of solute clearance in brain changes with alterations in both state of neuronal activity and CSF formation. Our clearance pathway and mechanism agnostic kinetic model informs about net solute transport, solely based on the measured time signal curves. This rather simplifying approach largely accords with preclinical and clinical findings.
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Affiliation(s)
- Martin Segeroth
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
- Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Lydia Wachsmuth
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Mathias Gagel
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Franziska Albers
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Andreas Hess
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
- Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
- FAU NeW, Research Center for New Bioactive Compounds, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Cornelius Faber
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany.
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Abstract
The adequacy of hemodialysis is now assessed by measuring the removal of the single-solute urea. The urea clearance provided by contemporary dialysis is a large fraction of the blood flow through the dialyzer and therefore cannot be increased much further. Other solutes however likely contribute more than urea to the residual uremic illness suffered by hemodialysis patients. We here review methods which could be employed to increase the clearance of nonurea solutes. We will separately consider the clearances of free low-molecular-mass solutes, free larger solutes, and protein-bound solutes. New clinical studies will be required to test the extent to which increasing the clearance on nonurea solutes with these various characteristics can improve patients' health.
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Affiliation(s)
- Seolhyun Lee
- The Department of Medicine, Stanford University, Palo Alto, California, USA
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California, USA
| | - Tammy L. Sirich
- The Department of Medicine, Stanford University, Palo Alto, California, USA
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California, USA
| | - Timothy W. Meyer
- The Department of Medicine, Stanford University, Palo Alto, California, USA
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California, USA
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Stapel SN, de Boer RJ, Thoral PJ, Vervloet MG, Girbes ARJ, Oudemans-van Straaten HM. Amino Acid Loss during Continuous Venovenous Hemofiltration in Critically Ill Patients. Blood Purif 2019; 48:321-329. [PMID: 31291614 DOI: 10.1159/000500998] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 05/14/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND/OBJECTIVES During continuous venovenous hemofiltration (CVVH), there is unwanted loss of amino acids (AA) in the ultrafiltrate (UF). Solutes may also be removed by adsorption to the filter membrane. The aim was to quantify the total loss of AA via the CVVH circuit using a high-flux polysulfone membrane and to differentiate between the loss by ultrafiltration and adsorption. METHODS Prospective observational study in ten critically ill patients, receiving predilution CVVH with a new filter, blood flow 180 mL/min, and predilution flow 2,400 mL/h. Arterial blood, postfilter blood, and UF samples were taken at baseline, and 1, 8, and 24-h after CVVH initiation, to determine AA concentrations and hematocrit. Mass transfer calculations were used to determine AA loss in the filter and by UF, and the difference between these 2. RESULTS The median AA loss in the filter was 10.4 g/day, the median AA loss by UF was 13.4 g/day, and the median difference was -2.9 g/day (IQR -5.9 to -1.4 g/day). For the individual AA, the difference ranged from -1 g/day to +0.4 g/day, suggesting that some AA were consumed or adsorbed and others were generated. AA losses did not significantly change over the 24-h study period. CONCLUSION During CVVH with a modern polysulfone membrane, the estimated AA loss was 13.4 g/day, which corresponds to a loss of about 11.2 g of protein per day. Adsorption did not play a major role. However, individual AA behaved differently, suggesting complex interactions and processes at the filter membrane or peripheral AA production.
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Affiliation(s)
- Sandra N Stapel
- Department of Adult Intensive Care Medicine, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, The Netherlands,
| | - Ruben J de Boer
- Department of Adult Intensive Care Medicine, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, The Netherlands
| | - Patrick J Thoral
- Department of Adult Intensive Care Medicine, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, The Netherlands
| | - Marc G Vervloet
- Department of Nephrology, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, The Netherlands
| | - Armand R J Girbes
- Department of Adult Intensive Care Medicine, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, The Netherlands
| | - Heleen M Oudemans-van Straaten
- Department of Adult Intensive Care Medicine, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, The Netherlands
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Albargothy NJ, Sharp MM, Gatherer M, Morris A, Weller RO, Hawkes C, Carare RO. Investigating the Lymphatic Drainage of the Brain: Essential Skills and Tools. Methods Mol Biol 2017; 1559:343-365. [PMID: 28063056 DOI: 10.1007/978-1-4939-6786-5_24] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In this chapter we describe in detail the surgical and imaging techniques employed for the study of the anatomical routes of drainage of cerebrospinal fluid (CSF) and interstitial fluid (ISF) from the brain. The types of tracers, sites of injection, and volumes injected are crucial. For example, when testing the drainage of ISF from the parenchyma, volumes larger than 0.5 μL result in spillage of ISF into the ventricular CSF.
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Affiliation(s)
- Nazira J Albargothy
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Matthew MacGregor Sharp
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Maureen Gatherer
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Alan Morris
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Roy O Weller
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Cheryl Hawkes
- Department of Life, Health and Chemical Sciences, Open University, Milton Keynes, UK
| | - Roxana O Carare
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK.
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Silverberg GD, Miller MC, Pascale CL, Caralopoulos IN, Agca Y, Agca C, Stopa EG. Kaolin-induced chronic hydrocephalus accelerates amyloid deposition and vascular disease in transgenic rats expressing high levels of human APP. Fluids Barriers CNS 2015; 12:2. [PMID: 25685319 PMCID: PMC4328504 DOI: 10.1186/2045-8118-12-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/14/2015] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Normal pressure hydrocephalus (NPH) is most common in the elderly and has a high co-morbidity with Alzheimer's disease (AD) and cerebrovascular disease (CVD). To understand the relationship between NPH, AD and CVD, we investigated how chronic hydrocephalus impacts brain amyloid-beta peptide (Aβ) accumulation and vascular pathology in an AD transgenic rodent model. Previously we showed that the altered CSF physiology produced by kaolin-hydrocephalus in older wild-type Sprague-Dawley rats increased Aβ and hyperphosphorylated Tau (Silverberg et. al. Brain Res. 2010, 1317:286-296). We postulated that hydrocephalus would similarly affect an AD rat model. METHODS Thirty-five transgenic rats (tgAPP21) that express high levels of human APP and naturally overproduce Aβ40 were used. Six- (n = 7) and twelve-month-old (n = 9) rats had hydrocephalus induced by cisternal kaolin injection. We analyzed Aβ burden (Aβ40, Aβ42 and oligomeric Aβ) and vascular integrity (Masson trichrome and Verhoeff-Van Gieson) by immunohistochemistry and chemical staining at 10 weeks (n = 8) and 6 months (n = 5) post hydrocephalus induction. We also analyzed whether the vascular pathology seen in tgAPP21 rats, which develop amyloid angiopathy, was accelerated by hydrocephalus. Age-matched naïve and sham-operated tgAPP21 rats served as controls (n = 19). RESULTS In hydrocephalic tgAPP21 rats, compared to naïve and sham-operated controls, there was increased Aβ 40 and oligomeric Aβ in hippocampal and cortical neurons at 10 weeks and 6 months post-hydrocephalus induction. No dense-core amyloid plaques were seen, but diffuse Aβ immunoreactivity was evident in neurons. Vascular pathology was accelerated by the induction of hydrocephalus compared to controls. In the six-month-old rats, subtle degenerative changes were noted in vessel walls at 10 weeks post-kaolin, whereas at six months post-kaolin and in the 12-month-old hydrocephalic rats more pronounced amyloid angiopathic changes were seen, with frequent large areas of infarction noted. CONCLUSIONS Kaolin-hydrocephalus can accelerate intraneuronal Aβ40 accumulation and vascular pathology in tgAPP21 rats. In addition, disrupted CSF production and reduced CSF turnover results in impaired Aβ clearance and accelerated vascular pathology in chronic hydrocephalus. The high co-morbidity seen in NPH, AD and CVD is likely not to be an age-related coincidence, but rather a convergence of pathologies related to diminished CSF clearance.
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Affiliation(s)
- Gerald D Silverberg
- />Department of Neurosurgery, The Warren Alpert Medical School of Brown University and the Aldrich Laboratories at Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 USA
- />Stanford University, 710 Frenchmans Rd, Stanford, CA 94305 USA
| | - Miles C Miller
- />Department of Neurosurgery, The Warren Alpert Medical School of Brown University and the Aldrich Laboratories at Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 USA
| | - Crissey L Pascale
- />Department of Neurosurgery, The Warren Alpert Medical School of Brown University and the Aldrich Laboratories at Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 USA
| | - Ilias N Caralopoulos
- />Department of Neurosurgery, The Warren Alpert Medical School of Brown University and the Aldrich Laboratories at Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 USA
| | - Yuksel Agca
- />Department of Veterinary Pathobiology, University of Missouri College of Veterinary Medicine, Columbia, MO 65211 USA
| | - Cansu Agca
- />Department of Veterinary Pathobiology, University of Missouri College of Veterinary Medicine, Columbia, MO 65211 USA
| | - Edward G Stopa
- />Department of Neurosurgery, The Warren Alpert Medical School of Brown University and the Aldrich Laboratories at Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 USA
- />Department of Pathology (Neuropathology), Warren Alpert Medical School of Brown University and the Aldrich Laboratories at Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 USA
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