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Villela-Torres MDLL, Prado-Uribe MDC, Díaz MÁ, Pablo HQ, Soria-Castro E, Escofet NE, Maldonado CEF, Paniagua R. Effect of High Sodium Intake on Gut Tight Junctions' Structure and Permeability to Bacterial Toxins in a Rat Model of Chronic Kidney Disease. Arch Med Res 2024; 55:102969. [PMID: 38484487 DOI: 10.1016/j.arcmed.2024.102969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 01/19/2024] [Accepted: 02/06/2024] [Indexed: 04/22/2024]
Abstract
INTRODUCTION Uremic toxicity changes the gut structure and permeability, allowing bacterial toxins to translocate from the lumen to the blood during chronic kidney failure (CKD). Clinical fluid overload and tissue edema without uremia have similar effects but have not been adequately demonstrated and analyzed in CKD. AIMS To investigate the effect of sodium intake on the plasma concentration of gut-derived uremic toxins, indoxyl sulfate (IS), and p-cresyl sulfate (pCS) and the expression of genes and proteins of epithelial gut tight junctions in a rat model of CKD. METHODS Sham-operated (control group, CG) and five-sixths nephrectomized (5/6Nx) Sprague-Dawley rats were randomly assigned to low (LNa), normal (NNa), or high sodium (HNa) diets., Animals were then sacrificed at 8 and 12 weeks and analyzed for IS and pCS plasma concentrations, as well as for gene and protein expression of thigh junction proteins, and transmission electron microscopy (TEM) in colon fragments. RESULTS The HNa 5/6Nx groups had higher concentrations of IS and pCS than CG, NNa, and LNa at eight and twelve weeks. Furthermore, HNa 5/6Nx groups had reduced expression of the claudin-4 gene and protein than CG, NNa, and LNa. HNa had reduced occludin gene expression compared to CG. Occludin protein expression was more reduced in HNa than in CG, NNa, and LNa. The gut epithelial tight junctions appear dilated in HNa compared to NNa and LNa in TEM. CONCLUSION Dietary sodium intake and fluid overload have a significant role in gut epithelial permeability in the CKD model.
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Affiliation(s)
- María de la Luz Villela-Torres
- Medical Research Unit in Nephrological Diseases, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - María-Del-Carmen Prado-Uribe
- Medical Research Unit in Nephrological Diseases, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Marcela Ávila Díaz
- Medical Research Unit in Nephrological Diseases, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Héctor Quezada Pablo
- Immunnology and Proteomics Research Lab, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Elizabeth Soria-Castro
- Cardiovascular Biomedicine Department, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Nuria Esturau Escofet
- Physical Chemistry Department, Laboratorio Universitario de Resonancia Magnética Nuclear, Instituto de Química, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - Ramón Paniagua
- Medical Research Unit in Nephrological Diseases, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
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Yoshida T, Tsuruoka N, Haga Y, Kinoshita H, Lee SS, Matsunaga T. Automatic irrigation system with a fiber-optic pressure sensor regulating intrapelvic pressure for flexible ureteroscopy. Sci Rep 2023; 13:22853. [PMID: 38129475 PMCID: PMC10739729 DOI: 10.1038/s41598-023-47373-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023] Open
Abstract
Increased intrapelvic pressure (IPP) due to irrigation during flexible ureteroscopy (f-URS) can pose a risk of postoperative severe urinary tract infection associated with pyelovenous backflow. An automatic regulation system for maintaining safe IPP levels could enable surgeons to perform f-URS safely without postoperative complications. This study aimed to assess the measurement accuracy of an ultra-miniature fiber-optic pressure sensor incorporated into a small-caliper ureteroscope for assessing IPP and to develop an automatic irrigation system linked to this sensor. A porcine kidney was used for the ex vivo experiment. The nephrostomy catheter, connected to the conventional pressure transducer, was placed on the renal pelvis to evaluate the actual IPP (a-IPP). For measuring IPP using the fiber-optic pressure sensor (fo-IPP) built into the f-URS, a diaphragm pressure sensor of Φ250 μm was used. To establish an irrigation system, the optimal proportional-integral-derivative (PID) controller was explored to accurately adjust the irrigation pump flow rate. A high correlation between a-IPP and fo-IPP was confirmed across irrigation pressure values of 60-180 mbar (all, r ≥ 0.7, p < 0.001). When performing bolus irrigation, although fo-IPP showed relatively a higher peak value than a-IPP, the response time of fo-IPP was equivalent to that of a-IPP. After PID parameter optimization, our automatic irrigation system based on fo-IPP smoothly and accurately regulated the intended IPP set in the 5-20 mmHg range without overshooting. We successfully developed and demonstrated an automatic irrigation system regulating IPP based on the PID controller for f-URS, utilizing a fiber-optic pressure sensor. Further research, including in vivo studies, will be needed to assess clinical feasibility.
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Affiliation(s)
- Takashi Yoshida
- Graduate School of Engineering, Tottori University, Tottori, Japan
- Department of Urology and Andrology, Kansai Medical University, Osaka, Japan
| | - Noriko Tsuruoka
- Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Yoichi Haga
- Graduate School of Engineering, Tohoku University, Sendai, Japan
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Hidefumi Kinoshita
- Department of Urology and Andrology, Kansai Medical University, Osaka, Japan
| | - Sang-Seok Lee
- Graduate School of Engineering, Tottori University, Tottori, Japan
- Advanced Mechanical and Electronic System Research Center, Faculty of Engineering, Tottori University, 4-101 Koyama Minami, Tottori, 680-8552, Japan
| | - Tadao Matsunaga
- Graduate School of Engineering, Tottori University, Tottori, Japan.
- Advanced Mechanical and Electronic System Research Center, Faculty of Engineering, Tottori University, 4-101 Koyama Minami, Tottori, 680-8552, Japan.
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Wang H, Lu J, Rathod M, Aw WY, Huang SA, Polacheck WJ. A facile fluid pressure system reveals differential cellular response to interstitial pressure gradients and flow. BIOMICROFLUIDICS 2023; 17:054103. [PMID: 37781136 PMCID: PMC10539030 DOI: 10.1063/5.0165119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 09/09/2023] [Indexed: 10/03/2023]
Abstract
Interstitial fluid pressure gradients and interstitial flow have been shown to drive morphogenic processes that shape tissues and influence progression of diseases including cancer. The advent of porous media microfluidic approaches has enabled investigation of the cellular response to interstitial flow, but questions remain as to the critical biophysical and biochemical signals imparted by interstitial fluid pressure gradients and resulting flow on resident cells and extracellular matrix (ECM). Here, we introduce a low-cost method to maintain physiological interstitial fluid pressures that is built from commonly accessible laboratory equipment, including a laser pointer, camera, Arduino board, and a commercially available linear actuator. We demonstrate that when the system is connected to a microfluidic device containing a 3D porous hydrogel, physiologic pressure is maintained with sub-Pascal resolution and when basic feedback control is directed using an Arduino, constant pressure and pressure gradient can be maintained even as cells remodel and degrade the ECM hydrogel over time. Using this model, we characterized breast cancer cell growth and ECM changes to ECM fibril structure and porosity in response to constant interstitial fluid pressure or constant interstitial flow. We observe increased collagen fibril bundling and the formation of porous structures in the vicinity of cancer cells in response to constant interstitial fluid pressure as compared to constant interstitial flow. Collectively, these results further define interstitial fluid pressure as a driver of key pathogenic responses in cells, and the systems and methods developed here will allow for future mechanistic work investigating mechanotransduction of interstitial fluid pressures and flows.
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Affiliation(s)
- Hao Wang
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, USA
| | - Jingming Lu
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, USA
| | - Mitesh Rathod
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, USA
| | - Wen Yih Aw
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, USA
| | - Stephanie A. Huang
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, USA
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Stauss M, Htay H, Kooman JP, Lindsay T, Woywodt A. Wearables in Nephrology: Fanciful Gadgetry or Prêt-à-Porter? SENSORS (BASEL, SWITZERLAND) 2023; 23:1361. [PMID: 36772401 PMCID: PMC9919296 DOI: 10.3390/s23031361] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/20/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Telemedicine and digitalised healthcare have recently seen exponential growth, led, in part, by increasing efforts to improve patient flexibility and autonomy, as well as drivers from financial austerity and concerns over climate change. Nephrology is no exception, and daily innovations are underway to provide digitalised alternatives to current models of healthcare provision. Wearable technology already exists commercially, and advances in nanotechnology and miniaturisation mean interest is also garnering clinically. Here, we outline the current existing wearable technology pertaining to the diagnosis and monitoring of patients with a spectrum of kidney disease, give an overview of wearable dialysis technology, and explore wearables that do not yet exist but would be of great interest. Finally, we discuss challenges and potential pitfalls with utilising wearable technology and the factors associated with successful implementation.
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Affiliation(s)
- Madelena Stauss
- Department of Nephrology, Lancashire Teaching Hospitals NHS Foundation Trust, Preston PR2 9HT, UK
| | - Htay Htay
- Department of Renal Medicine, Singapore General Hospital, Singapore 169608, Singapore
| | - Jeroen P. Kooman
- Department of Internal Medicine, Division of Nephrology, Maastricht University, 6229 HX Maastricht, The Netherlands
| | - Thomas Lindsay
- Department of Nephrology, Lancashire Teaching Hospitals NHS Foundation Trust, Preston PR2 9HT, UK
| | - Alexander Woywodt
- Department of Nephrology, Lancashire Teaching Hospitals NHS Foundation Trust, Preston PR2 9HT, UK
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Williams ME, Steenkamp D, Wolpert H. Making sense of glucose sensors in end-stage kidney disease: A review. FRONTIERS IN CLINICAL DIABETES AND HEALTHCARE 2022; 3:1025328. [PMID: 36992784 PMCID: PMC10012164 DOI: 10.3389/fcdhc.2022.1025328] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/27/2022] [Indexed: 12/23/2022]
Abstract
Diabetes mellitus remains the leading cause of end-stage kidney disease worldwide. Inadequate glucose monitoring has been identified as one of the gaps in care for hemodialysis patients with diabetes, and lack of reliable methods to assess glycemia has contributed to uncertainty regarding the benefit of glycemic control in these individuals. Hemoglobin A1c, the standard metric to evaluate glycemic control, is inaccurate in patients with kidney failure, and does not capture the full range of glucose values for patients with diabetes. Recent advances in continuous glucose monitoring have established this technology as the new gold standard for glucose management in diabetes. Glucose fluctuations are uniquely challenging in patients dependent on intermittent hemodialysis, and lead to clinically significant glycemic variability. This review evaluates continuous glucose monitoring technology, its validity in the setting of kidney failure, and interpretation of glucose monitoring results for the nephrologist. Continuous glucose monitoring targets for patients on dialysis have yet to be established. While continuous glucose monitoring provides a more complete picture of the glycemic profile than hemoglobin A1c and can mitigate high-risk hypoglycemia and hyperglycemia in the context of the hemodialysis procedure itself, whether the technology can improve clinical outcomes merits further investigation.
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Affiliation(s)
- Mark E. Williams
- Renal Unit, Joslin Diabetes Center, Boston MA, United States
- *Correspondence: Mark E. Williams,
| | - Devin Steenkamp
- Section of Endocrinology, Diabetes, and Nutrition, Department of Medicine, Boston Medical Center, Boston, MA, United States
| | - Howard Wolpert
- Boston University School of Medicine, Boston, MA, United States
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6
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Aronson D. The interstitial compartment as a therapeutic target in heart failure. Front Cardiovasc Med 2022; 9:933384. [PMID: 36061549 PMCID: PMC9428749 DOI: 10.3389/fcvm.2022.933384] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/15/2022] [Indexed: 12/23/2022] Open
Abstract
Congestion is the single most important contributor to heart failure (HF) decompensation. Most of the excess volume in patients with HF resides in the interstitial compartment. Inadequate decongestion implies persistent interstitial congestion and is associated with worse outcomes. Therefore, effective interstitial decongestion represents an unmet need to improve quality of life and reduce clinical events. The key processes that underlie incomplete interstitial decongestion are often ignored. In this review, we provide a summary of the pathophysiology of the interstitial compartment in HF and the factors governing the movement of fluids between the interstitial and vascular compartments. Disruption of the extracellular matrix compaction occurs with edema, such that the interstitium becomes highly compliant, and large changes in volume marginally increase interstitial pressure and allow progressive capillary filtration into the interstitium. Augmentation of lymph flow is required to prevent interstitial edema, and the lymphatic system can increase fluid removal by at least 10-fold. In HF, lymphatic remodeling can become insufficient or maladaptive such that the capacity of the lymphatic system to remove fluid from the interstitium is exceeded. Increased central venous pressure at the site of the thoracic duct outlet also impairs lymphatic drainage. Owing to the kinetics of extracellular fluid, microvascular absorption tends to be transient (as determined by the revised Starling equation). Therefore, effective interstitial decongestion with adequate transcapillary plasma refill requires a substantial reduction in plasma volume and capillary pressure that are prolonged and sustained, which is not always achieved in clinical practice. The critical importance of the interstitium in the congestive state underscores the need to directly decongest the interstitial compartment without relying on the lowering of intracapillary pressure with diuretics. This unmet need may be addressed by novel device therapies in the near future.
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Gregg LP, Van Buren PN, Ramsey DJ, Maydon A, Banerjee S, Walther CP, Virani SS, Winkelmayer WC, Navaneethan SD, Hedayati SS. Natriuretic peptides, extracellular volume, and subclinical cardiovascular changes in chronic kidney disease stages 1-3: a pilot study. J Investig Med 2022; 70:jim-2022-002467. [PMID: 35853670 PMCID: PMC10461401 DOI: 10.1136/jim-2022-002467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2022] [Indexed: 11/03/2022]
Abstract
Natriuretic peptide levels are elevated in persons with chronic kidney disease (CKD) stages 1-3, but it remains unclear whether this is associated with extracellular volume excess or early cardiovascular changes. We hypothesized that patients with CKD stages 1-3 would have evidence of cardiovascular changes, which would associate with brain natriuretic peptide (BNP), amino-terminal-pro-BNP (NT-pro-BNP), and patient-reported symptoms.Outpatients with CKD stages 1-3 and non-CKD controls were enrolled. Cardiovascular parameters included extracellular water (ECW) normalized to body weight measured using whole-body multifrequency bioimpedance spectroscopy, and total peripheral resistance index (TPRI) and cardiac index measured by impedance cardiography. Dyspnea, fatigue, depression, and quality of life were quantified using questionnaires.Among 21 participants (13 with CKD), median (IQR) BNP was 47.0 (28.0-302.5) vs 19.0 (12.3-92.3) pg/mL, p=0.07, and NT-pro-BNP was 245.0 (52.0-976.8) vs 26.0 (14.5-225.8) pg/mL, p=0.08, in the CKD and control groups, respectively. Those with CKD had higher pulse pressure (79 (66-87) vs 64 (49-67) mm Hg, p=0.046) and TPRI (3721 (3283-4278) vs 2933 (2745-3198) dyn×s/cm5/m2, p=0.01) and lower cardiac index (2.28 (2.08-2.78) vs 3.08 (2.43-3.37) L/min/m2, p=0.02). In the overall cohort, natriuretic peptides correlated with pulse pressure (BNP r=0.59; NT-pro-BNP r=0.58), cardiac index (BNP r=-0.76; NT-pro-BNP r=-0.62), and TPRI (BNP r=0.48), p<0.05 for each, but not with ECW/weight. TPRI and blood pressure correlated moderately with symptoms.Elevated natriuretic peptides may coincide with low cardiac index and elevated peripheral resistance in patients with CKD stages 1-3. The role of these biomarkers to detect subclinical cardiovascular changes needs to be further explored.
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Affiliation(s)
- L Parker Gregg
- Selzman Institute for Kidney Health, Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
- Medical Care Line, Section of Nephrology, Michael E DeBakey Veterans Affairs Medical Center, Houston, Texas, USA
- Veterans Affairs Health Services Research and Development Center for Innovations in Quality, Effectiveness and Safety, Houston, Texas, USA
| | - Peter N Van Buren
- Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Medical Service, Renal Section, Veterans Affairs North Texas Health Care System, Dallas, Texas, USA
| | - David J Ramsey
- Veterans Affairs Health Services Research and Development Center for Innovations in Quality, Effectiveness and Safety, Houston, Texas, USA
| | - Amaris Maydon
- Mental Health Service, Veterans Affairs North Texas Health Care System, Dallas, Texas, USA
| | - Subhash Banerjee
- Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Medical Service, Cardiology Section, Veterans Affairs North Texas Health Care System, Dallas, Texas, USA
| | - Carl P Walther
- Selzman Institute for Kidney Health, Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Salim S Virani
- Veterans Affairs Health Services Research and Development Center for Innovations in Quality, Effectiveness and Safety, Houston, Texas, USA
- Internal Medicine, Section of Cardiology, Baylor College of Medicine, Houston, Texas, USA
- Internal Medicine, Section of Cardiology, Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas, USA
| | - Wolfgang C Winkelmayer
- Selzman Institute for Kidney Health, Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Sankar D Navaneethan
- Selzman Institute for Kidney Health, Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
- Medical Care Line, Section of Nephrology, Michael E DeBakey Veterans Affairs Medical Center, Houston, Texas, USA
- Veterans Affairs Health Services Research and Development Center for Innovations in Quality, Effectiveness and Safety, Houston, Texas, USA
- Institute of Clinical and Translational Research, Baylor College of Medicine, Houston, Texas, USA
| | - S Susan Hedayati
- Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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8
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The effects of gravity and compression on interstitial fluid transport in the lower limb. Sci Rep 2022; 12:4890. [PMID: 35318426 PMCID: PMC8941011 DOI: 10.1038/s41598-022-09028-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
Edema in the limbs can arise from pathologies such as elevated capillary pressures due to failure of venous valves, elevated capillary permeability from local inflammation, and insufficient fluid clearance by the lymphatic system. The most common treatments include elevation of the limb, compression wraps and manual lymphatic drainage therapy. To better understand these clinical situations, we have developed a comprehensive model of the solid and fluid mechanics of a lower limb that includes the effects of gravity. The local fluid balance in the interstitial space includes a source from the capillaries, a sink due to lymphatic clearance, and movement through the interstitial space due to both gravity and gradients in interstitial fluid pressure (IFP). From dimensional analysis and numerical solutions of the governing equations we have identified several parameter groups that determine the essential length and time scales involved. We find that gravity can have dramatic effects on the fluid balance in the limb with the possibility that a positive feedback loop can develop that facilitates chronic edema. This process involves localized tissue swelling which increases the hydraulic conductivity, thus allowing the movement of interstitial fluid vertically throughout the limb due to gravity and causing further swelling. The presence of a compression wrap can interrupt this feedback loop. We find that only by modeling the complex interplay between the solid and fluid mechanics can we adequately investigate edema development and treatment in a gravity dependent limb.
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Ford RL, Klifto MR, Knight OJ, Jain K, Wiesen C, Fleischman D. Chronic Kidney Disease as a Predictor of Postoperative Choroidal Effusions After Glaucoma Surgery. J Glaucoma 2021; 30:981-987. [PMID: 34224488 DOI: 10.1097/ijg.0000000000001908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 06/19/2021] [Indexed: 11/26/2022]
Abstract
PRCIS Patients with chronic kidney disease (CKD) are at increased risk for choroidal effusion development following glaucoma surgery. PURPOSE Choroidal effusion is a postoperative complication of glaucoma surgery that results from a transudative fluid collection in the suprachoroidal space. Kidney disease alters bodily fluid dynamics through a variety of mechanisms. The relationship between CKD and choroidal effusion following glaucoma surgery has not previously been studied. The purpose of this study was to determine the relationship between CKD and choroidal effusion development after glaucoma surgery. PATIENTS AND METHODS This retrospective cohort study consisted of 86 eyes from 86 patients who received glaucoma filtering surgery or transscleral cyclophotocoagulation within the study timeframe. Forty-three patients had CKD, and 43 patients did not have kidney disease. The main outcome of this study was the development of choroidal effusion measured by the Pearson χ2 test and multivariate analysis using a binomial regression with a log link. RESULTS Ten patients (23.3%) in the CKD group developed choroidal effusion, while 2 patients (4.7%) in the no-kidney disease group developed choroidal effusion (relative risk, 5.0; 95% confidence interval: 1.16-21.5; P=0.013). The association between CKD and choroidal effusion showed mixed results in the multivariate analysis, with some analyses showing a significant association and others showing no significant association. CONCLUSIONS In both the univariate and multivariate analyses, CKD was found to be significantly associated with choroidal effusion after glaucoma surgery.
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Affiliation(s)
| | | | | | - Koyal Jain
- Medicine, Division of Nephrology and Hypertension
| | - Chris Wiesen
- Odom Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC
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Abstract
Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood sampling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can address most of the challenges associated with dermal ISF extraction and is well suited for long-term, continuous ISF monitoring as well as in situ detection. In this review, we first briefly summarise the different dermal ISF collection methods and compare them with MN methods. Next, we elaborate on the design considerations and biocompatibility of MNs. Subsequently, the fabrication technologies of various MNs used for dermal ISF extraction, including solid MNs, hollow MNs, porous MNs, and hydrogel MNs, are thoroughly explained. In addition, different sensing mechanisms of ISF detection are discussed in detail. Subsequently, we identify the challenges and propose the possible solutions associated with ISF extraction. A detailed investigation is provided for the transport and sampling mechanism of ISF in vivo. Also, the current in vitro skin model integrated with the MN arrays is discussed. Finally, future directions to develop a point-of-care (POC) device to sample ISF are proposed.
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11
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Shelton EL, Yang HC, Zhong J, Salzman MM, Kon V. Renal lymphatic vessel dynamics. Am J Physiol Renal Physiol 2020; 319:F1027-F1036. [PMID: 33103446 DOI: 10.1152/ajprenal.00322.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Similar to other organs, renal lymphatics remove excess fluid, solutes, and macromolecules from the renal interstitium. Given the kidney's unique role in maintaining body fluid homeostasis, renal lymphatics may be critical in this process. However, little is known regarding the pathways involved in renal lymphatic vessel function, and there are no studies on the effects of drugs targeting impaired interstitial clearance, such as diuretics. Using pressure myography, we showed that renal lymphatic collecting vessels are sensitive to changes in transmural pressure and have an optimal range of effective pumping. In addition, they are responsive to vasoactive factors known to regulate tone in other lymphatic vessels including prostaglandin E2 and nitric oxide, and their spontaneous contractility requires Ca2+ and Cl-. We also demonstrated that Na+-K+-2Cl- cotransporter Nkcc1, but not Nkcc2, is expressed in extrarenal lymphatic vessels. Furosemide, a loop diuretic that inhibits Na+-K+-2Cl- cotransporters, induced a dose-dependent dilation in lymphatic vessels and decreased the magnitude and frequency of spontaneous contractions, thereby reducing the ability of these vessels to propel lymph. Ethacrynic acid, another loop diuretic, had no effect on vessel tone. These data represent a significant step forward in our understanding of the mechanisms underlying renal lymphatic vessel function and highlight potential off-target effects of furosemide that may exacerbate fluid accumulation in edema-forming conditions.
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Affiliation(s)
- Elaine L Shelton
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Hai-Chun Yang
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee
| | - Jianyong Zhong
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee
| | - Michele M Salzman
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Valentina Kon
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
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12
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Canaud B, Kooman J, Selby NM, Taal M, Francis S, Kopperschmidt P, Maierhofer A, Kotanko P, Titze J. Sodium and water handling during hemodialysis: new pathophysiologic insights and management approaches for improving outcomes in end-stage kidney disease. Kidney Int 2020; 95:296-309. [PMID: 30665570 DOI: 10.1016/j.kint.2018.09.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/22/2018] [Accepted: 09/24/2018] [Indexed: 02/07/2023]
Abstract
Space medicine and new technology such as magnetic resonance imaging of tissue sodium stores (23NaMRI) have changed our understanding of human sodium homeostasis and pathophysiology. It has become evident that body sodium comprises 3 main components. Two compartments have been traditionally recognized, namely one that is circulating and systemically active via its osmotic action, and one slowly exchangeable pool located in the bones. The third, recently described pool represents sodium stored in skin and muscle interstitium, and it is implicated in cell and biologic activities via local hypertonicity and sodium clearance mechanisms. This in-depth review provides a comprehensive view on the pathophysiology and existing knowledge gaps of systemic hemodynamic and tissue sodium accumulation in dialysis patients. Furthermore, we discuss how the combination of novel technologies to quantitate tissue salt accumulation (e.g., 23NaMRI) with devices to facilitate the precise attainment of a prescribed hemodialytic sodium mass balance (e.g., sodium and water balancing modules) will improve our therapeutic approach to sodium management in dialysis patients. While prospective studies are required, we think that these new diagnostic and sodium balancing tools will enhance our ability to pursue more personalized therapeutic interventions on sodium and water management, with the eventual goal of improving dialysis patient outcomes.
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Affiliation(s)
- Bernard Canaud
- Centre for Medical Excellence, Fresenius Medical Care Deutschland, Bad Homburg, Germany; Montpellier University, Montpellier, France.
| | - Jeroen Kooman
- Maastricht Universitair Medisch Centrum - Maastricht, Netherlands
| | - Nicholas M Selby
- Centre for Kidney Research and Innovation, University of Nottingham, Royal Derby Hospital Campus, Derby, UK
| | - Maarten Taal
- Centre for Kidney Research and Innovation, University of Nottingham, Royal Derby Hospital Campus, Derby, UK
| | - Susan Francis
- Sir Peter Mansfield Imaging Centre, University of Nottingham, UK
| | | | | | - Peter Kotanko
- Renal Research Institute, New York, New York, USA; Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jens Titze
- Division of Cardiovascular and Metabolic Disease, Duke-NUS, Singapore; Division of Nephrology, Duke University Medical Center, Durham, North Carolina, USA; Division of Nephrology and Hypertension, University Clinic Erlangen, Germany
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13
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Nigam SK, Bush KT. Uraemic syndrome of chronic kidney disease: altered remote sensing and signalling. Nat Rev Nephrol 2019; 15:301-316. [PMID: 30728454 DOI: 10.1038/s41581-019-0111-1] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Uraemic syndrome (also known as uremic syndrome) in patients with advanced chronic kidney disease involves the accumulation in plasma of small-molecule uraemic solutes and uraemic toxins (also known as uremic toxins), dysfunction of multiple organs and dysbiosis of the gut microbiota. As such, uraemic syndrome can be viewed as a disease of perturbed inter-organ and inter-organism (host-microbiota) communication. Multiple biological pathways are affected, including those controlled by solute carrier (SLC) and ATP-binding cassette (ABC) transporters and drug-metabolizing enzymes, many of which are also involved in drug absorption, distribution, metabolism and elimination (ADME). The remote sensing and signalling hypothesis identifies SLC and ABC transporter-mediated communication between organs and/or between the host and gut microbiota as key to the homeostasis of metabolites, antioxidants, signalling molecules, microbiota-derived products and dietary components in body tissues and fluid compartments. Thus, this hypothesis provides a useful perspective on the pathobiology of uraemic syndrome. Pathways considered central to drug ADME might be particularly important for the body's attempts to restore homeostasis, including the correction of disturbances due to kidney injury and the accumulation of uraemic solutes and toxins. This Review discusses how the remote sensing and signalling hypothesis helps to provide a systems-level understanding of aspects of uraemia that could lead to novel approaches to its treatment.
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Affiliation(s)
- Sanjay K Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA. .,Department of Medicine, University of California San Diego, La Jolla, CA, USA.
| | - Kevin T Bush
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA
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14
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Zhang H, Chan L, Meyring-Wösten A, Campos I, Preciado P, Kooman JP, van der Sande FM, Fuertinger D, Thijssen S, Kotanko P. Association between intradialytic central venous oxygen saturation and ultrafiltration volume in chronic hemodialysis patients. Nephrol Dial Transplant 2019; 33:1636-1642. [PMID: 28927232 PMCID: PMC6113642 DOI: 10.1093/ndt/gfx271] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/31/2017] [Indexed: 12/15/2022] Open
Abstract
Background Cardiac disease is highly prevalent in hemodialysis (HD) patients. Decreased tissue perfusion, including cardiac, due to high ultrafiltration volumes (UFVs) is considered to be one of the drivers of cardiac dysfunction. While central venous oxygen saturation (ScvO2) is frequently used as an indicator of cardiac output in non-uremic populations, the relationship of ScvO2 and UFV in HD patients remains unclear. Our aim was to determine how intradialytic ScvO2 changes associate with UFV. Methods We conducted a 6-month retrospective cohort study in maintenance HD patients with central venous catheters as vascular access. Intradialytic ScvO2 was measured with the Critline monitor. We computed treatment-level slopes of intradialytic ScvO2 over time (ScvO2 trend) and applied linear mixed effects models to assess the association between patient-level ScvO2 trends and UFV corrected for body weight (cUFV). Results We studied 6042 dialysis sessions in 232 patients. In about 62.4% of treatments, ScvO2 decreased. We observed in nearly 80% of patients an inverse relationship between cUFV and ScvO2 trend, indicating that higher cUFV is associated with steeper decline in ScvO2 during dialysis. Conclusions In most patients, higher cUFV volumes are associated with steeper intradialytic ScvO2 drops. We hypothesize that in a majority of patients the intradialytic cardiac function is fluid dependent, so that in the face of high ultrafiltration rates or volume, cardiac pre-load and consequently cardiac output decreases. Direct measurements of cardiac hemodynamics are warranted to further test this hypothesis.
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Affiliation(s)
| | - Lili Chan
- Department of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | | | - Jeroen P Kooman
- Department of Internal Medicine Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Frank M van der Sande
- Department of Internal Medicine Maastricht University Medical Centre, Maastricht, The Netherlands
| | | | | | - Peter Kotanko
- Renal Research Institute, New York, NY, USA.,Department of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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15
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Goraya N, Simoni J, Sager LN, Mamun A, Madias NE, Wesson DE. Urine citrate excretion identifies changes in acid retention as eGFR declines in patients with chronic kidney disease. Am J Physiol Renal Physiol 2019; 317:F502-F511. [PMID: 31215805 DOI: 10.1152/ajprenal.00044.2019] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Previous studies have shown that acid (H+) retention in patients with chronic kidney disease (CKD) but without metabolic acidosis increases as the estimated glomerular filtration rate (eGFR) decreases over time. The present study examined whether changes in urine excretion of the pH-sensitive metabolite citrate predicted changes in H+ retention over time in similar patients with CKD that were followed for 10 yr. We randomized 120 CKD2 nondiabetic, hypertension-associated nephropathy patients with plasma total CO2 of >24 mM to receive 0.5 meq·kg body wt-1·day-1 NaHCO3 ([Formula: see text]; n = 40), 0.5 meq·kg body wt-1·day-1 NaCl (NaCl; n = 40), or usual care (UC; n = 40). We assessed eGFR (CKD-EPI) and H+ retention by comparing the observed with expected plasma total CO2 increase 2 h after an oral NaHCO3 bolus (0.5 meq/kg body wt). Although 10 yr versus baseline eGFR was lower for each group, 10-yr eGFR was higher (P < 0.01) in [Formula: see text] (59.6 ± 4.8 ml·min-1·1.73 m-2) than NaCl and UC (52.1 ± 5.9 and 52.3 ± 4.1 ml·min-1·1.73 m-2, respectively) groups. Less eGFR preservation was associated with higher 10-yr versus baseline H+ retention in the NaCl group (26.5 ± 13.1 vs. 18.2 ± 15.3 mmol, P < 0.01) and UC group (24.8 ± 11.3 vs. 17.7 ± 10.9 mmol, P < 0.01) and with lower 10-yr versus baseline 8-h urine citrate excretion (UcitrateV) for the NaCl group (162 ± 47 vs. 196 ± 52 mg, respectively, P < 0.01) and UC group (153 ± 41 vs. 186 ± 42 mg, respectively, P < 0.01). Conversely, better eGFR preservation in the [Formula: see text] group was associated with no differences in 10-yr versus baseline H+ retention (14.2 ±13.5 vs. 16.1 ± 15.1 mmol, P = 1.00) or UcitrateV (212 ± 45 vs. 203 ± 49 mg, respectively, P = 0.74). An overall generalized linear model for repeated measures showed that UcitrateV predicted H+ retention (P < 0.01). Less eGFR preservation in patients with CKD2 without metabolic acidosis was associated with increased H+ retention that was predicted by decreased UcitrateV.
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Affiliation(s)
- Nimrit Goraya
- Baylor Scott and White Health Department of Internal Medicine, Temple, Texas.,Texas A&M Health Sciences Center, College of Medicine, Temple Texas
| | - Jan Simoni
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Lauren N Sager
- Baylor Scott and White Health Department of Biostatistics, Temple, Texas
| | - Abdullah Mamun
- Baylor Scott and White Health and Wellness Center, Dallas, Texas
| | - Nicolaos E Madias
- School of Medicine, Department of Medicine, St. Elizabeth's Medical Center and Tufts University, Boston, Massachusetts
| | - Donald E Wesson
- Baylor Scott and White Health Department of Internal Medicine, Dallas, Texas.,Texas A&M Health Sciences Center, College of Medicine, Dallas, Texas
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16
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Possenti L, di Gregorio S, Gerosa FM, Raimondi G, Casagrande G, Costantino ML, Zunino P. A computational model for microcirculation including Fahraeus-Lindqvist effect, plasma skimming and fluid exchange with the tissue interstitium. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3165. [PMID: 30358172 DOI: 10.1002/cnm.3165] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 09/06/2018] [Accepted: 10/19/2018] [Indexed: 06/08/2023]
Abstract
We present a two-phase model for microcirculation that describes the interaction of plasma with red blood cells. The model takes into account of typical effects characterizing the microcirculation, such as the Fahraeus-Lindqvist effect and plasma skimming. Besides these features, the model describes the interaction of capillaries with the surrounding tissue. More precisely, the model accounts for the interaction of capillary transmural flow with the surrounding interstitial pressure. Furthermore, the capillaries are represented as one-dimensional channels with arbitrary, possibly curved configuration. The latter two features rely on the unique ability of the model to account for variations of flow rate and pressure along the axis of the capillary, according to a local differential formulation of mass and momentum conservation. Indeed, the model stands on a solid mathematical foundation, which is also addressed in this work. In particular, we present the model derivation, the variational formulation, and its approximation using the finite element method. Finally, we conclude the work with a comparative computational study of the importance of the Fahraeus-Lindqvist, plasma skimming, and capillary leakage effects on the distribution of flow in a microvascular network.
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Affiliation(s)
- Luca Possenti
- LaBS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Simone di Gregorio
- LaBS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Milan, Italy
- MOX, Department of Mathematics, Politecnico di Milano, Milan, Italy
| | | | - Giorgio Raimondi
- MOX, Department of Mathematics, Politecnico di Milano, Milan, Italy
| | - Giustina Casagrande
- LaBS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Maria Laura Costantino
- LaBS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Paolo Zunino
- MOX, Department of Mathematics, Politecnico di Milano, Milan, Italy
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17
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Goraya N, Simoni J, Sager LN, Madias NE, Wesson DE. Urine citrate excretion as a marker of acid retention in patients with chronic kidney disease without overt metabolic acidosis. Kidney Int 2019; 95:1190-1196. [PMID: 30846270 DOI: 10.1016/j.kint.2018.11.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 11/17/2018] [Accepted: 11/21/2018] [Indexed: 11/30/2022]
Abstract
Acid (H+) retention appears to contribute to progressive decline in glomerular filtration rate (GFR) in patients with chronic kidney disease (CKD), including some patients without metabolic acidosis. Identification of patients with H+ retention but without metabolic acidosis could facilitate targeted alkali therapy; however, current methods to assess H+ retention are invasive and have little clinical utility. We tested the hypothesis that urine excretion of the pH-sensitive metabolite citrate can identify H+ retention in patients with reduced GFR but without overt metabolic acidosis. H+ retention was assessed based on the difference between observed and expected plasma total CO2 after an oral sodium bicarbonate load. The association between H+ retention and urine citrate excretion was evaluated in albuminuric CKD patients with eGFR 60-89 ml/min/1.73m2 (CKD 2, n=40) or >90 ml/min/1.73m2 (CKD 1, n = 26) before and after 30 days of base-producing fruits and vegetables. Baseline H+ retention was higher in CKD 2, while baseline urine citrate excretion was lower in CKD 2 compared to CKD 1. Base-producing fruits and vegetables decreased H+ retention in CKD 2 and increased urine citrate excretion in both groups. Thus, H+ retention is associated with lower urine citrate excretion, and reduction of H+ retention with a base-producing diet is associated with increased urine citrate excretion. These results support further exploration of the utility of urine citrate excretion to identify H+ retention in CKD patients with reduced eGFR but without metabolic acidosis, to determine their candidacy for kidney protection with dietary H+ reduction or alkali therapy.
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Affiliation(s)
- Nimrit Goraya
- Baylor Scott & White Health Department of Internal Medicine, Temple, Texas, USA; Texas A&M Health Sciences Center College of Medicine, Temple, Texas, USA
| | - Jan Simoni
- Texas Tech University Health Sciences Center Department of Surgery, Lubbock, Texas, USA
| | - Lauren N Sager
- Baylor Scott & White Health Department of Biostatistics, Temple, Texas, USA
| | - Nicolaos E Madias
- St. Elizabeth's Medical Center and Tufts University School of Medicine Department of Medicine, Boston, Massachusetts, USA
| | - Donald E Wesson
- Baylor Scott & White Health Department of Internal Medicine, Dallas, Texas, USA; Texas A&M Health Sciences Center College of Medicine, Dallas, Texas, USA.
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18
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Fluid status assessment in hemodialysis patients and the association with outcome: review of recent literature. Curr Opin Nephrol Hypertens 2019; 27:188-193. [PMID: 29621026 DOI: 10.1097/mnh.0000000000000409] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW In this review, we will discuss the most recent literature regarding fluids status assessment in hemodialysis patients, and the associations with outcome. RECENT FINDINGS Research toward technique-assisted assessment of fluid status in hemodialysis patients has been going on for many years. However, there is no absolute agreement between techniques, such as bioimpedance, lung ultrasound, biochemical markers or vena caval diameter, likely because they reflect different fluid compartments with potentially altered distribution in hemodialysis patients. Recent studies, mostly based on bioimpedance, have shown not only an association of severe, but also of moderate predialysis fluid overload with overall survival. Also predialysis fluid depletion has been found to associate with and increased mortality risk. Interventional studies with fluid-guided management are scarce and outline the difficulties of achieving dry weight is the dialysis population. SUMMARY Optimal estimation of predialysis fluid status remains challenging and may require a combination of clinical and technical derived parameters. There appears to be a narrow window of optimal predialysis fluid status. Further clinical studies are necessary to identify strategies to improve survival in hemodialysis patients with abnormalities in fluid status.
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19
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Pietribiasi M, Waniewski J, Wójcik-Załuska A, Załuska W, Lindholm B. Model of fluid and solute shifts during hemodialysis with active transport of sodium and potassium. PLoS One 2018; 13:e0209553. [PMID: 30592754 PMCID: PMC6310262 DOI: 10.1371/journal.pone.0209553] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 12/07/2018] [Indexed: 11/19/2022] Open
Abstract
Background Mathematical models are useful tools to predict fluid shifts between body compartments in patients undergoing hemodialysis (HD). The ability of a model to accurately describe the transport of water between cells and interstitium (Jv,ISIC), and the consequent changes in intracellular volume (ICV), is important for a complete assessment of fluid distribution and plasma refilling. In this study, we propose a model describing transport of fluid in the three main body compartments (intracellular, interstitial and vascular), complemented by transport mechanisms for proteins and small solutes. Methods The model was applied to data from 23 patients who underwent standard HD. The substances described in the baseline model were: water, proteins, Na, K, and urea. Small solutes were described with two-compartment kinetics between intracellular and extracellular compartments. Solute transport across the cell membrane took place via passive diffusion and, for Na and K, through the ATPase pump, characterized by the maximum transport rate, JpMAX. From the data we estimated JpMAX and two other parameters linked to transcapillary transport of fluid and protein: the capillary filtration coefficient Lp and its large pores fraction αLP. In an Expanded model one more generic solute was included to evaluate the impact of the number of substances appearing in the equation describing Jv,ISIC. Results In the baseline model, median values (interquartile range) of estimated parameters were: Lp: 11.63 (7.9, 14.2) mL/min/mmHg, αLP: 0.056 (0.050, 0.058), and JpMAX: 5.52 (3.75, 7.54) mmol/min. These values were significantly different from those obtained by the Expanded model: Lp: 8.14 (6.29, 10.01) mL/min/mmHg, αLP: 0.046 (0.038, 0.052), and JpMAX: 16.7 (11.9, 25.2) mmol/min. The relative RMSE (root mean squared error)averaged between all simulated quantities compared to data was 3.9 (3.1, 5.6) %. Conclusions The model was able to accurately reproduce most of the changes observed in HD by tuning only three parameters. While the drop in ICV was overestimated by the model, the difference between simulations and data was less than the measurement error. The biggest change in the estimated parameters in the Expanded model was a marked increase of JpMAX indicating that this parameter is highly sensitive to the number of species modeled, and that the value of JpMAX should be interpreted only in relation to this factor.
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Affiliation(s)
- Mauro Pietribiasi
- Nalecz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
- * E-mail:
| | - Jacek Waniewski
- Nalecz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Alicja Wójcik-Załuska
- Department of Rehabilitation and Physiotherapy, Medical University of Lublin, Lublin, Poland
| | - Wojciech Załuska
- Department of Nephrology, Medical University of Lublin, Lublin, Poland
| | - Bengt Lindholm
- Renal Medicine and Baxter Novum, Karolinska Institutet, Stockholm, Sweden
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20
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Possenti L, Casagrande G, Di Gregorio S, Zunino P, Costantino ML. Numerical simulations of the microvascular fluid balance with a non-linear model of the lymphatic system. Microvasc Res 2018; 122:101-110. [PMID: 30448400 DOI: 10.1016/j.mvr.2018.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 11/08/2018] [Accepted: 11/08/2018] [Indexed: 02/03/2023]
Abstract
Fluid homeostasis is required for life. Processes involved in fluid balance are strongly related to exchanges at the microvascular level. Computational models have been presented in the literature to analyze the microvascular-interstitial interactions. As far as we know, none of those models consider a physiological description for the lymphatic drainage-interstitial pressure relation. We develop a computational model that consists of a network of straight cylindrical vessels and an isotropic porous media with a uniformly distributed sink term acting as the lymphatic system. In order to describe the lymphatic flow rate, a non-linear function of the interstitial pressure is defined, based on literature data on the lymphatic system. The proposed model of lymphatic drainage is compared to a linear one, as is typically used in computational models. To evaluate the response of the model, the two are compared with reference to both physiological and pathological conditions. Differences in the local fluid dynamic description have been observed using the non-linear model. In particular, the distribution of interstitial pressure is heterogeneous in all the cases analyzed. The resulting averaged values of the interstitial pressure are also different, and they agree with literature data when using the non-linear model. This work highlights the key role of lymphatic drainage and its modeling when studying the fluid balance in microcirculation for both to physiological and pathological conditions, e.g. uremia.
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Affiliation(s)
- Luca Possenti
- LaBS, Chemistry, Material and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Italy.
| | - Giustina Casagrande
- LaBS, Chemistry, Material and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Italy
| | - Simone Di Gregorio
- LaBS, Chemistry, Material and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Italy; MOX, Department of Mathematics, Politecnico di Milano, Italy
| | - Paolo Zunino
- MOX, Department of Mathematics, Politecnico di Milano, Italy
| | - Maria Laura Costantino
- LaBS, Chemistry, Material and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Italy
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21
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Kaburaki S, Yoshimura E, Kojima N, Ueno H, Sugawara M, Takekuma Y. Improvement of renal function estimation equations for elderly Japanese people. Health Sci Rep 2018; 1:e85. [PMID: 30623041 PMCID: PMC6266418 DOI: 10.1002/hsr2.85] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/25/2018] [Accepted: 07/27/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND AND AIM The Cockcroft-Gault (C-G) equation for estimation of creatinine clearance (CCr) is still used in a clinical setting for drug dosage adjustment. Because differences between measured and estimated CCr values have been reported, particularly for Japanese elderly people, the aim of this study was to improve the accuracy of CCr estimation equations, such as C-G and Orita-Horio, by fitting to newly obtained data. Also, glomerular filtration rate (GFR) estimation equations, such as the Modification of Diet in Renal Disease (MDRD), the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and the eGFR equation for Japanese people, were studied to compare with measured CCr. METHOD Data from 313 subjects over the age of 40 years with laboratory data available were used for analysis in this study. Special attention was paid to elderly people, and approximately 70% of the subjects were over the age of 65 years. RESULTS The accuracy of estimation by the two conventional (C-G, Orita-Horio) CCr estimation equations was greatly improved by introducing adjusted body weight for which the degree of obesity is over 30% instead of measured body weight. By fitting the coefficients of the estimation equations to the present population, the mean error was reduced by almost half, particularly for people over the age of 75. Although all the values calculated by the GFR estimation equations were underestimated compared with measured CCr due to secretion, a coefficient of determination of above 0.65 was obtained for all GFR estimation equations. CONCLUSIONS Improvement of the fitted CCr estimation equations suggests that reconstruction of renal function estimation equations is required, especially for old people. Further work is required to find optimal renal function (CCr and/or GFR) estimation equations for drug dosage adjustment.
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Affiliation(s)
- Soyoko Kaburaki
- Graduate School of Life ScienceHokkaido UniversitySapporoJapan
| | - Eri Yoshimura
- Department of PharmacySunagawa City Medical CenterSunagawaJapan
| | - Nozomi Kojima
- Department of PharmacySunagawa City Medical CenterSunagawaJapan
| | - Hidefumi Ueno
- Department of PharmacySunagawa City Medical CenterSunagawaJapan
| | - Mitsuru Sugawara
- Faculty of Pharmaceutical SciencesHokkaido UniversitySapporoJapan
| | - Yoh Takekuma
- Faculty of Pharmaceutical SciencesHokkaido UniversitySapporoJapan
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22
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A model of vascular refilling with inflammation. Math Biosci 2018; 303:101-114. [DOI: 10.1016/j.mbs.2018.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 05/31/2018] [Accepted: 06/25/2018] [Indexed: 12/17/2022]
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Goraya N, Wesson DE. Kidney Response to the Spectrum of Diet-Induced Acid Stress. Nutrients 2018; 10:nu10050596. [PMID: 29751620 PMCID: PMC5986476 DOI: 10.3390/nu10050596] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/01/2018] [Accepted: 05/08/2018] [Indexed: 12/16/2022] Open
Abstract
Chronic ingestion of the acid (H+)-producing diets that are typical of developed societies appears to pose a long-term threat to kidney health. Mechanisms employed by kidneys to excrete this high dietary H+ load appear to cause long-term kidney injury when deployed over many years. In addition, cumulative urine H+ excretion is less than the cumulative increment in dietary H+, consistent with H+ retention. This H+ retention associated with the described high dietary H+ worsens as the glomerular filtration rate (GFR) declines which further exacerbates kidney injury. Modest H+ retention does not measurably change plasma acid–base parameters but, nevertheless, causes kidney injury and might contribute to progressive nephropathy. Current clinical methods do not detect H+ retention in its early stages but the condition manifests as metabolic acidosis as it worsens, with progressive decline of the glomerular filtration rate. We discuss this spectrum of H+ injury, which we characterize as “H+ stress”, and the emerging evidence that high dietary H+ constitutes a threat to long-term kidney health.
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Affiliation(s)
- Nimrit Goraya
- Baylor Scott & White Health Department of Internal Medicine, Temple, TX 76508, USA.
- A&M Health Science Center College of Medicine, Temple, TX 76508, USA.
| | - Donald E Wesson
- Baylor Scott & White Health Department of Internal Medicine, Dallas, TX 75210, USA.
- A&M Health Science Center College of Medicine, Dallas, TX 75210, USA.
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Abstract
PURPOSE OF REVIEW The aim of this article is to present current information on techniques for fluid status assessment in patients with kidney disease. The methods can be broadly categorized into biomarkers, ultrasound, blood volume monitoring, and bioimpedance. RECENT FINDINGS Biomarkers including atrial natriuretic peptide and B-type natriuretic peptide have been shown to provide information about relative changes in fluid status. Ultrasound is applied to measure inferior vena cava indices, pulmonary indicators, and vascular indicators of fluid overload. Relative blood volume monitoring is used to measure change in intravascular fluid during hemodialysis. While in principle appealing, measurement of absolute blood volume has seen limited use to date. Bioimpedance techniques such as vector analysis, whole body, and regional bioimpedance spectroscopy, have shown their ability to estimate fluid status. SUMMARY The interpretation of biomarkers is complicated by the presence of cardiac disease. All ultrasound methods have some correlation with fluid status; however, operator dependency limits their routine use. Bioimpedance methods and relative blood volume monitoring are increasingly used to assess fluid status in patients with acute or chronic kidney disease. Measurement of absolute blood volume holds promise for the future.
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25
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Goraya N, Simoni J, Sager LN, Pruszynski J, Wesson DE. Acid retention in chronic kidney disease is inversely related to GFR. Am J Physiol Renal Physiol 2018; 314:F985-F991. [PMID: 29357423 DOI: 10.1152/ajprenal.00463.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Greater H+ retention in animal models of chronic kidney disease (CKD) mediates faster glomerular filtration rate (GFR) decline and dietary H+ reduction slows eGFR decline in CKD patients with reduced eGFR and H+ retention due to the high acid (H+) diets of developed societies. We examined if H+ retention in CKD is inversely associated with estimated GFR (eGFR) using cross-sectional and longitudinal analysis of individuals with CKD stage 1 (>90 ml·min- 1·1.73 m-2), CKD stage 2 (60-89 ml/min per 1.73 m2), and CKD stage 3 (30-59 ml·min- 1·1.73 m-2) eGFR. H+ retention was assessed using the difference between observed and expected plasma total CO2 2 h after 0.5 meq/kg body wt oral NaHCO3. H+ retention was higher in CKD 2 vs. CKD 1 ( P < 0.01) and in CKD 3 vs. CKD 2 ( P < 0.02) at baseline and 5 yr, and was higher in CKD 2 vs. CKD 1 ( P < 0.01) at 10 yr. All groups had lower eGFR at subsequent time points ( P < 0.01) but H+ retention was not different among the three time points for CKD 1. By contrast, eGFR decrease was associated with higher H+ retention in CKD 2 at 5 yr ( P = 0.04) and 10 yr ( P < 0.01) and with higher H+ retention in CKD 3 at 5 yr ( P < 0.01). Yearly eGFR decline rate was faster in CKD 2 vs. CKD 1 ( P < 0.01) and in CKD 3 vs. CKD 2 ( P < 0.01). The data show that H+ retention is inversely associated with eGFR, with faster eGFR decline, and support the need for greater dietary H+ reduction therapy for CKD individuals with lower eGFR.
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Affiliation(s)
- Nimrit Goraya
- Department of Internal Medicine, Texas A&M College of Medicine, Temple, Texas.,Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Jan Simoni
- Department of Surgery, Texas Tech University Health Sciences Center , Lubbock, Texas
| | - Lauren N Sager
- Department of Biostatistics, Baylor Scott & White Health, Temple, Texas
| | - Jessica Pruszynski
- Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern , Dallas, Texas
| | - Donald E Wesson
- Department of Internal Medicine, Texas A&M Health Sciences Center College of Medicine , Dallas, Texas.,Baylor Scott & White Health and Wellness Center, Dallas, Texas
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Ellison DH. Treatment of Disorders of Sodium Balance in Chronic Kidney Disease. Adv Chronic Kidney Dis 2017; 24:332-341. [PMID: 29031361 DOI: 10.1053/j.ackd.2017.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 07/25/2017] [Indexed: 12/23/2022]
Abstract
Extracellular fluid volume expansion is nearly universal in patients with CKD. Such volume expansion has features similar to the syndrome of heart failure with preserved ejection fraction, which not only leads to symptoms but can also lead to further organ damage. Unique treatment challenges are present in this patient population, including low glomerular filtration, which limits sodium chloride filtration, intrinsic tubule predisposition to sodium chloride retention, and proteinuria. In addition, pharmacokinetic considerations alter the disposition of diuretics in patients with CKD and nephrotic syndrome. Maintaining extracellular fluid volume near to normal is often necessary for hypertension treatment in this population, but it may also help prevent progressive cardiovascular and kidney damage. Although powerful diuretics can often accomplish this goal, this often comes at a cost of competing adverse effects. An approach to reduce extracellular fluid volume while avoiding adverse effects, therefore, requires a nuanced yet aggressive therapeutic approach.
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The interaction between fluid status and angiopoietin-2 in adverse renal outcomes of chronic kidney disease. PLoS One 2017; 12:e0173906. [PMID: 28333979 PMCID: PMC5363828 DOI: 10.1371/journal.pone.0173906] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 02/28/2017] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Fluid overload is not only the characteristic but also an important complication in chronic kidney disease (CKD) patients. Angiopoietin-2 (Angpt2) disturbs endothelium and vessel permeability, which may induce fluid overload. The aim of this study is to examine the interaction between fluid status and Angpt2 in adverse renal outcomes of CKD. METHODS This cohort study enrolled 290 patients with CKD stages 3-5 from January 2011 to December 2011 and followed up until December 2015. Fluid status was presented as overhydration (OH) value measured by body composition monitor, while OH>1.1L was defined as fluid overload. Renal outcomes were defined as commencing dialysis and rapid renal function decline (the slope of estimated glomerular filtration rate < -5 ml/min/1.73 m2/y). RESULTS During a mean follow-up of 38.6±18.3 months, 125 (43.1%) patients progressed to commencing dialysis and 99(34.7%) patients presented rapid renal function decline. All patients were stratified by OH of 1.1L and the median of circulating Angpt2. These patients with both OH>1.1L and high circulating Angpt2 were more likely to reach commencing dialysis compared to other groups. The risks for commencing dialysis and rapid renal function decline were significantly higher in patients with OH>1.1L and high circulating Angpt2 level compared to those with OH≦1.1L and low circulating Angpt2 (2.14, 1.21-3.78, P = 0.009; 4.96, 1.45-16.97, P = 0.01). There was a significant interaction between OH level and circulating Angpt2 in entering dialysis (P-interaction = 0.02). CONCLUSIONS Fluid overload and Angpt2 might have a synergistic effect on adverse renal outcomes in CKD patients.
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Wesson DE, Pruszynski J, Cai W, Simoni J. Acid retention with reduced glomerular filtration rate increases urine biomarkers of kidney and bone injury. Kidney Int 2016; 91:914-927. [PMID: 27988208 DOI: 10.1016/j.kint.2016.10.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 10/09/2016] [Accepted: 10/13/2016] [Indexed: 11/18/2022]
Abstract
Diets high in acid of developed societies that do not cause metabolic acidosis in patients with chronic kidney disease nevertheless appear to cause acid retention with associated morbidity, particularly in those with reduced glomerular filtration rate. Here we used a rat 2/3 nephrectomy model of chronic kidney disease to study induction and maintenance of acid retention and its consequences on indicators of kidney and bone injury. Dietary acid was increased in animals eating base-producing soy protein with acid-producing casein and in casein-eating animals with added ammonium chloride. Using microdialysis to measure the kidney cortical acid content, we found that nephrectomized animals had greater acid retention than sham-operated animals when both ate the soy diet. Each increment in dietary acid further increased acid retention more in nephrectomized than in sham rats. Nephrectomized and sham animals achieved similar steady-state daily urine net acid excretion in response to increments in dietary acid but nephrectomized animals took longer to do so, contributing to greater acid retention that was maintained until the increased dietary acid was stopped. Acid retention was associated with increased urine excretion of both N-acetyl-β-D-glucosaminidase and deoxypyridinoline, greater in nephrectomized than control rats, consistent with kidney tubulointerstitial and bone matrix injury, respectively. Greater acid retention in nephrectomized than control animals was induced by a slower increase in urinary net acid excretion rate in response to the increment in dietary acid and also maintained until the dietary acid increment was stopped. Thus, acid retention increased biomarkers of kidney and bone injury in the urine, supporting untoward consequences to these two tissues.
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Affiliation(s)
- Donald E Wesson
- Baylor Scott and White Health, Dallas, TX, USA; Department of Medicine, Texas A&M College of Medicine, Temple, TX, USA.
| | - Jessica Pruszynski
- Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Wendy Cai
- Department of Biostatistics, Baylor Scott and White Health, Temple, TX, USA
| | - Jan Simoni
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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Neyra JA, Li X, Canepa-Escaro F, Adams-Huet B, Toto RD, Yee J, Hedayati SS. Cumulative Fluid Balance and Mortality in Septic Patients With or Without Acute Kidney Injury and Chronic Kidney Disease. Crit Care Med 2016; 44:1891-900. [PMID: 27352125 PMCID: PMC5505731 DOI: 10.1097/ccm.0000000000001835] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Incident acute kidney injury and prevalent chronic kidney disease are commonly encountered in septic patients. We examined the differential effect of acute kidney injury and chronic kidney disease on the association between cumulative fluid balance and hospital mortality in critically ill septic patients. DESIGN Retrospective cohort study. SETTING Urban academic medical center ICU. PATIENTS ICU adult patients with severe sepsis or septic shock and serum creatinine measured within 3 months prior to and 72 hours of ICU admission. Patients with estimated glomerular filtration rate less than 15 mL/min/1.73 m or receiving chronic dialysis were excluded. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS A total of 2,632 patients, 1,211 with chronic kidney disease, were followed up until hospital death or discharge. Acute kidney injury occurred in 1,525 patients (57.9%), of whom 679 (44.5%) had chronic kidney disease. Hospital mortality occurred in 603 patients (22.9%). Every 1-L increase in cumulative fluid balance at 72 hours of ICU admission was independently associated with hospital mortality in all patients (adjusted odds ratio, 1.06 [95% CI] 1.04-1.08; p < 0.001), and in each acute kidney injury/chronic kidney disease subgroup (adjusted odds ratio, 1.06 [1.03-1.09] for acute kidney injury+/chronic kidney disease+; 1.09 [1.05-1.13] for acute kidney injury-/chronic kidney disease+; 1.05 [1.03-1.08] for acute kidney injury+/chronic kidney disease-; and 1.07 [1.02-1.11] for acute kidney injury-/chronic kidney disease-). There was a significant interaction between acute kidney injury and chronic kidney disease on cumulative fluid balance (p =0.005) such that different cumulative fluid balance cut-offs with the best prognostic accuracy for hospital mortality were identified: 5.9 L for acute kidney injury+/chronic kidney disease+; 3.8 L for acute kidney injury-/chronic kidney disease+; 4.3 L for acute kidney injury+/chronic kidney disease-; and 1.5 L for acute kidney injury-/chronic kidney disease-. The addition of cumulative fluid balance to the admission Sequential Organ Failure Assessment score had increased prognostic utility for hospital mortality when compared with Sequential Organ Failure Assessment alone, particularly in patients with acute kidney injury. CONCLUSIONS Higher cumulative fluid balance at 72 hours of ICU admission was independently associated with hospital mortality regardless of acute kidney injury or chronic kidney disease presence. We characterized cumulative fluid balance cut-offs associated with hospital mortality based on acute kidney injury/chronic kidney disease status, underpinning the heterogeneity of fluid regulation in sepsis and kidney disease.
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Affiliation(s)
- Javier A. Neyra
- Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Xilong Li
- Department of Clinical Sciences, Division of Biostatistics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Beverley Adams-Huet
- Department of Clinical Sciences, Division of Biostatistics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Robert D. Toto
- Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jerry Yee
- Division of Nephrology and Hypertension, Henry Ford Hospital, Detroit, Michigan, USA
| | - S. Susan Hedayati
- Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Renal Section, Medical Service, Veterans Affairs North Texas Health Care System, Dallas, Texas, USA
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Pietribiasi M, Waniewski J, Załuska A, Załuska W, Lindholm B. Modelling Transcapillary Transport of Fluid and Proteins in Hemodialysis Patients. PLoS One 2016; 11:e0159748. [PMID: 27483369 PMCID: PMC4970790 DOI: 10.1371/journal.pone.0159748] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/07/2016] [Indexed: 11/18/2022] Open
Abstract
Background The kinetics of protein transport to and from the vascular compartment play a major role in the determination of fluid balance and plasma refilling during hemodialysis (HD) sessions. In this study we propose a whole-body mathematical model describing water and protein shifts across the capillary membrane during HD and compare its output to clinical data while evaluating the impact of choosing specific values for selected parameters. Methods The model follows a two-compartment structure (vascular and interstitial space) and is based on balance equations of protein mass and water volume in each compartment. The capillary membrane was described according to the three-pore theory. Two transport parameters, the fractional contribution of large pores (αLP) and the total hydraulic conductivity (LpS) of the capillary membrane, were estimated from patient data. Changes in the intensity and direction of individual fluid and solute flows through each part of the transport system were analyzed in relation to the choice of different values of small pores radius and fractional conductivity, lymphatic sensitivity to hydraulic pressure, and steady-state interstitial-to-plasma protein concentration ratio. Results The estimated values of LpS and αLP were respectively 10.0 ± 8.4 mL/min/mmHg (mean ± standard deviation) and 0.062 ± 0.041. The model was able to predict with good accuracy the profiles of plasma volume and serum total protein concentration in most of the patients (average root-mean-square deviation < 2% of the measured value). Conclusions The applied model provides a mechanistic interpretation of fluid transport processes induced by ultrafiltration during HD, using a minimum of tuned parameters and assumptions. The simulated values of individual flows through each kind of pore and lymphatic absorption rate yielded by the model may suggest answers to unsolved questions on the relative impact of these not-measurable quantities on total vascular refilling and fluid balance.
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Affiliation(s)
- Mauro Pietribiasi
- Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland
- * E-mail:
| | - Jacek Waniewski
- Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland
| | - Alicja Załuska
- Department of Rehabilitation and Physiotherapy, Medical University of Lublin, Lublin, Poland
| | - Wojciech Załuska
- Department of Nephrology, Medical University of Lublin, Lublin, Poland
| | - Bengt Lindholm
- Baxter Novum and Renal Medicine, Karolinska Institutet, Stockholm, Sweden
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A physiologically based model of vascular refilling during ultrafiltration in hemodialysis. J Theor Biol 2015; 390:146-55. [PMID: 26643943 DOI: 10.1016/j.jtbi.2015.11.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 10/27/2015] [Accepted: 11/03/2015] [Indexed: 11/22/2022]
Abstract
An assessment of fluid status can be obtained by monitoring relative blood volume (RBV) during hemodialysis (HD) treatment. The dynamics of RBV is determined by fluid removal from the intravascular compartment by ultrafiltration (UF) and vascular refill from the interstitium. To characterize this dynamics, a two-compartment model describing the short-term dynamics of vascular refilling and UF is developed. Fluid movement between the compartments is governed by lymphatic and microvascular fluid shifts. Further, protein flux is described by convection, diffusion and the lymphatic protein flux. Patient specific parameters are identified based on hematocrit (Hct) measurements by the Crit-Line monitor (CLM). Different measurement frequencies and UF profiles are compared to determine data fidelity and influence on the quality of parameter estimates. This relevant information can be used to assess the (patho)physiological status of hemodialysis patients and could aid in individualizing therapy.
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Nijst P, Verbrugge FH, Grieten L, Dupont M, Steels P, Tang WHW, Mullens W. The pathophysiological role of interstitial sodium in heart failure. J Am Coll Cardiol 2015; 65:378-388. [PMID: 25634838 DOI: 10.1016/j.jacc.2014.11.025] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 01/05/2023]
Abstract
The current understanding of heart failure (HF) does not fully explain the spectrum of HF symptoms. Most HF hospitalizations are related to sodium (Na(+)) and fluid retention resulting from neurohumoral up-regulation. Recent insights suggest that Na(+) is not distributed in the body solely as a free cation, but that it is also bound to large interstitial glycosaminoglycan (GAG) networks in different tissues, which have an important regulatory function. In HF, high Na(+) intake and neurohumoral alterations disrupt GAG structure, leading to loss of the interstitial buffer capacity and disproportionate interstitial fluid accumulation. Moreover, a diminished endothelial GAG network (the endothelial glycocalyx) results in increased vascular resistance and disturbed endothelial nitric oxide production. New imaging modalities can help evaluate interstitial Na(+) and endothelial glycocalyx integrity. Furthermore, several therapies have been proven to stabilize interstitial GAG networks. Hence, a better appreciation of this new Na(+) "compartment" might improve current management of HF.
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Affiliation(s)
- Petra Nijst
- Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Doctoral School for Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Frederik H Verbrugge
- Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Doctoral School for Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Lars Grieten
- Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Doctoral School for Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Matthias Dupont
- Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium
| | - Paul Steels
- Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - W H Wilson Tang
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio
| | - Wilfried Mullens
- Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium.
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Variability of laboratory parameters is associated with frailty markers and predicts non-cardiac mortality in hemodialysis patients. Clin Exp Nephrol 2015; 19:1165-78. [DOI: 10.1007/s10157-015-1108-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 03/03/2015] [Indexed: 10/23/2022]
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Tsai YC, Chiu YW, Tsai JC, Kuo HT, Hung CC, Hwang SJ, Chen TH, Kuo MC, Chen HC. Association of fluid overload with cardiovascular morbidity and all-cause mortality in stages 4 and 5 CKD. Clin J Am Soc Nephrol 2014; 10:39-46. [PMID: 25512646 DOI: 10.2215/cjn.03610414] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND AND OBJECTIVES Fluid overload is a common characteristic associated with renal progression in CKD. Additionally, fluid overload is an independent predictor of all-cause or cardiovascular mortality in patients on dialysis, but its influence on patients not on dialysis is uncertain. The aim of the study was to assess the relationship between the severity of fluid status and clinical outcomes in an advanced CKD cohort. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In total, 478 predialysis patients with stages 4 and 5 CKD in the integrated CKD care program were enrolled from January of 2011 to December of 2011 and followed-up until August of 2013. The clinical outcomes included cardiovascular morbidity and all-cause mortality. The relative hydration status (overhydration/extracellular water) was used as the presentation of the severity of fluid status and measured using a body composition monitor. Overhydration/extracellular water >7% was defined as fluid overload. RESULTS Over a median follow-up period of 23.2 (12.6-26.4) months, 66 (13.8%) patients reached all-cause mortality or cardiovascular morbidity. The adjusted hazard ratio of the combined outcome of all-cause mortality or cardiovascular morbidity for every 1% higher overhydration/extracellular water was 1.08 (95% confidence interval, 1.04 to 1.12; P<0.001). The adjusted overhydration/extracellular water for the combined outcome of all-cause mortality or cardiovascular morbidity in participants with overhydration/extracellular water ≥7% compared with those with overhydration/extracellular water <7% was 1.93 (95% confidence interval, 1.01 to 3.69; P=0.04). In subgroup analysis, higher overhydration/extracellular water was consistently associated with increased risk for the combined outcome independent of diabetes, cardiovascular disease, and serum albumin. There was no significant interaction between all subgroups. CONCLUSIONS These findings suggest that fluid overload is an independent risk factor of the combined outcome of all-cause mortality or cardiovascular morbidity in patients with advanced CKD.
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Affiliation(s)
- Yi-Chun Tsai
- Graduate Institute of Clinical Medicine and Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Wen Chiu
- Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jer-Chia Tsai
- Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Hung-Tien Kuo
- Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chi-Chih Hung
- Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shang-Jyh Hwang
- Graduate Institute of Clinical Medicine and Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan; Institute of Population Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Tzu-Hui Chen
- Department of Nursing, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; and
| | - Mei-Chuan Kuo
- Graduate Institute of Clinical Medicine and Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan;
| | - Hung-Chun Chen
- Division of Nephrology and Faculty of Renal Care, Kaohsiung Medical University, Kaohsiung, Taiwan
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Abstract
Extracellular volume expansion may lead to elevated blood pressure. This long-term adaptation of the vascular bed to extracellular volume overload is considered a multifactorial and not perfectly understood 'autoregulatory' event, which is difficult to measure. In this issue, Ebah and colleagues demonstrate a direct relationship between fluid overload and pressure in CKD patients. Surprise, instead of intravascular volume, interstitial fluids and pressures were measured. Finally!
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Padberg JS, Wiesinger A, di Marco GS, Reuter S, Grabner A, Kentrup D, Lukasz A, Oberleithner H, Pavenstädt H, Brand M, Kümpers P. Damage of the endothelial glycocalyx in chronic kidney disease. Atherosclerosis 2014; 234:335-43. [DOI: 10.1016/j.atherosclerosis.2014.03.016] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/24/2014] [Accepted: 03/17/2014] [Indexed: 01/22/2023]
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Mitra S. Extracellular hydration, cardiovascular risk, and the interstitium: a three-dimensional view. Kidney Int 2014; 85:510-2. [DOI: 10.1038/ki.2013.481] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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