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- Stachowska-Pietka, J, et al.
(författare)
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Alterations of peritoneal transport characteristics in dialysis patients with ultrafiltration failure: tissue and capillary components
- 2019
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Ingår i: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. - : Oxford University Press (OUP). - 1460-2385. ; 34:5, s. 864-870
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundUltrafiltration failure (UFF) in peritoneal dialysis (PD) patients is due to altered peritoneal transport properties leading to reduced capacity to remove excess water. Here, with the aim to establish the role of local alterations of the two major transport barriers, peritoneal tissue and capillary wall, we investigate changes in overall peritoneal transport characteristics in UFF patients in relation to corresponding local alterations of peritoneal tissue and capillary wall transport properties.MethodsSix-hour dwell studies using 3.86% glucose solutions and radioisotopically labelled serum albumin added to dialysate as a volume marker were analysed in 31 continuous ambulatory PD patients, 20 with normal ultrafiltration (NUF) and 11 with UFF. For each patient, the physiologically based parameters were evaluated for both transport barriers using the spatially distributed approach based on the individual intraperitoneal profiles of volume and concentrations of glucose, sodium, urea and creatinine.ResultsUFF patients as compared with NUF patients had increased solute diffusivity in both barriers, peritoneal tissue and capillary wall, decreased tissue hydraulic conductivity and increased local lymphatic absorption and functional decrease in the fraction of the ultra-small pores. This resulted in altered distribution of fluid and solutes in the peritoneal tissue, and decreased penetration depths of fluid and solutes into the tissue in UFF patients.ConclusionsMathematical modelling using a spatially distributed approach for the description of clinical data suggests that alterations both in the capillary wall and in the tissue barrier contribute to UFF through their effect on transport and distribution of solutes and fluid within the tissue.
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- Debowska, M, et al.
(författare)
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Association between Biomarkers of Mineral and Bone Metabolism and Removal of Calcium and Phosphate in Hemodialysis
- 2020
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Ingår i: Blood purification. - : S. Karger AG. - 1421-9735 .- 0253-5068. ; 49:1-2, s. 71-78
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background:</i></b> A significant drop of serum phosphate and calcium removal or loading during hemodialysis induce reactions in mineral and bone remodeling that may inversely affect phosphate and calcium removal during dialysis. <b><i>Objectives:</i></b> We aimed to analyze the interdependencies between biomarkers of mineral and bone metabolism and removal of phosphate and calcium during hemodialysis, as this complex relationship is not fully understood. <b><i>Methods:</i></b> Three subsequent hemodialysis sessions during a 1-week treatment cycle with interdialytic periods of 2–2-3 days were monitored in 25 anuric patients. Calcium and phosphate concentrations were measured in serum before, at 1, 2, and 3 h, at the end, and 45 min after each session and in the outlet dialysate every 30 min. Biomarkers associated with mineral and bone metabolism: parathyroid hormone (PTH 1–34 and PTH 1–84), calcitonin, 25(OH)-vitamin D, fetuin-A, osteopontin, osteocalcin 1–43/49, and intact osteocalcin were assayed once in each patient before the midweek hemodialysis session. <b><i>Results:</i></b> Post-dialytic and intra-dialytic serum phosphate of midweek hemodialysis session and phosphate mass removed within 1 week correlated positively with serum PTH (0.40 < rho <0.46, <i>p</i> value <0.05). Higher concentration of serum PTH was associated with an increased level of osteocalcin. Pre-dialytic, post-dialytic, average for treatment time and average weekly concentrations of ionized calcium in serum correlated positively with serum osteocalcin. Serum osteocalcin and osteopontin levels were associated with the masses of total and ionized calcium, respectively, removed during 3 hemodialysis sessions. <b><i>Conclusions:</i></b> During hemodialysis, phosphate removal was associated with serum PTH, whereas calcium kinetics was influenced by serum osteocalcin and osteopontin. These results demonstrate that active processes involving biomarkers of mineral and bone metabolism are affected by the phosphate and calcium kinetics already within 4 h hemodialysis sessions.
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| 8. |
- Debowska, M, et al.
(författare)
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Phosphate clearance in peritoneal dialysis
- 2020
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1, s. 17504-
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Tidskriftsartikel (refereegranskat)abstract
- In renal failure, hyperphosphatemia is common and correlates with increased mortality making phosphate removal a key priority for dialysis therapy. We investigated phosphate clearance, removal and serum level, and factors associated with phosphate control in patients undergoing continuous ambulatory (CAPD), continuous cyclic (CCPD) and automated (APD) peritoneal dialysis (PD). In 154 prevalent PD patients (mean age 53.2 ± 17.6 year, 59% men, 47% anuric), 196 daily collections of urine and 368 collections of dialysate were evaluated in terms of renal, peritoneal and total (renal plus peritoneal) phosphorus removal (g/week), phosphate and creatinine clearances (L/week) and urea KT/V. Dialytic removal of phosphorus was lower in APD (1.34 ± 0.62 g/week) than in CAPD (1.89 ± 0.73 g/week) and CCPD (1.91 ± 0.63 g/week) patients; concomitantly, serum phosphorus was higher in APD than in CAPD (5.55 ± 1.61 vs. 4.84 ± 1.23 mg/dL; p < 0.05). Peritoneal and total phosphate clearances correlated with peritoneal (rho = 0.93) and total (rho = 0.85) creatinine clearances (p < 0.001) but less with peritoneal and total urea KT/V (rho = 0.60 and rho = 0.65, respectively, p < 0.001). Phosphate removal, clearance and serum levels differed between PD modalities. CAPD was associated with higher peritoneal removal and lower serum level of phosphate than APD.
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- Pinto, J, et al.
(författare)
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Urine volume as an estimator of residual renal clearance and urinary removal of solutes in patients undergoing peritoneal dialysis
- 2022
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1, s. 18755-
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Tidskriftsartikel (refereegranskat)abstract
- In non-anuric patients undergoing peritoneal dialysis (PD), residual kidney function (RKF) is a main contributor to fluid and solute removal and an independent predictor of survival. We investigated if urine volume could be used to estimate renal clearances and removal of urea, creatinine, and phosphorus in PD patients. The observational, cross-sectional study included 93 non-anuric prevalent PD patients undergoing continuous ambulatory PD (CAPD; n = 34) or automated PD (APD; n = 59). Concentrations of urea, creatinine and phosphorus in serum and in 24-h collections of urine volume were measured to calculate weekly residual renal clearance (L/week) and removed solute mass (g/week). Median [interquartile range], 24-h urine output was 560 [330–950] mL and measured GFR (the mean of creatinine and urea clearances) was 3.24 [1.47–5.67] mL/min. For urea, creatinine and phosphorus, residual renal clearance was 20.60 [11.49–35.79], 43.02 [19.13–75.48] and 17.50 [8.34–33.58] L/week, respectively, with no significant differences between CAPD and APD. Urine volume correlated positively with removed solute masses (rho = 0.82, 0.67 and 0.74) and with weekly residual renal clearances (rho = 0.77, 0.62 and 0.72 for urea, creatinine, and phosphorus, respectively, all p < 0.001). Residual renal clearances and urinary mass removal rates for urea, creatinine, and phosphorus correlate strongly with 24-h urine volume suggesting that urine volume could serve as an estimator of typical values of residual solute removal indices in PD patients.
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- Stachowska-Pietka, J, et al.
(författare)
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Computer simulations of osmotic ultrafiltration and small-solute transport in peritoneal dialysis: a spatially distributed approach
- 2012
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Ingår i: American journal of physiology. Renal physiology. - : American Physiological Society. - 1522-1466 .- 1931-857X. ; 302:10, s. F1331-F1341
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to simulate clinically observed intraperitoneal kinetics of dialysis fluid volume and solute concentrations during peritoneal dialysis. We were also interested in analyzing relationships between processes in the peritoneal cavity and processes occurring in the peritoneal tissue and microcirculation. A spatially distributed model was formulated for the combined description of volume and solute mass balances in the peritoneal cavity and flows across the interstitium and the capillary wall. Tissue local parameters were assumed dependent on the interstitial hydration and vasodilatation induced by glucose. The model was fitted to the average volume and solute concentration profiles from dwell studies in 40 clinically stable patients on chronic ambulatory peritoneal dialysis using a 3.86% glucose dialysis solution. The model was able to describe the clinical data with high accuracy. An increase in the local interstitial pressure and tissue hydration within the distance of 2.5 mm from the peritoneal surface of the tissue was observed. The penetration of glucose into the tissue and removal of urea, creatinine, and sodium from the tissue were restricted to a layer located within 2 mm from the peritoneal surface. The initial decline of sodium concentration (sodium dip) was observed not only in intraperitoneal fluid but also in the tissue. The distributed model can provide a precise description of the relationship between changes in the peritoneal tissue and intraperitoneal dialysate volume and solute concentration kinetics. Computer simulations suggest that only a thin layer of the tissue within 2–3 mm from the peritoneal surface participates in the exchange of fluid and small solutes between the intraperitoneal dialysate and blood.
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- Stachowska-Pietka, J, et al.
(författare)
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Concomitant bidirectional transport during peritoneal dialysis can be explained by a structured interstitium
- 2016
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Ingår i: American journal of physiology. Heart and circulatory physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 310:11, s. H1501-H1511
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Tidskriftsartikel (refereegranskat)abstract
- Clinical and animal studies suggest that peritoneal absorption of fluid and protein from dialysate to peritoneal tissue, and to blood and lymph circulation, occurs concomitantly with opposite flows of fluid and protein, i.e., from blood to dialysate. However, until now a theoretical explanation of this phenomenon has been lacking. A two-phase distributed model is proposed to explain the bidirectional, concomitant transport of fluid, albumin and glucose through the peritoneal transport system (PTS) during peritoneal dialysis. The interstitium of this tissue is described as an expandable two-phase structure with phase F (water-rich, colloid-poor region) and phase C (water-poor, colloid-rich region) with fluid and solute exchange between them. A low fraction of phase F is assumed in the intact tissue, which can be significantly increased under the influence of hydrostatic pressure and tissue hydration. The capillary wall is described using the three-pore model, and the conditions in the peritoneal cavity are assumed commencing 3 min after the infusion of glucose 3.86% dialysis fluid. Computer simulations demonstrate that peritoneal absorption of fluid into the tissue, which occurs via phase F at the rate of 1.8 ml/min, increases substantially the interstitial pressure and tissue hydration in both phases close to the peritoneal cavity, whereas the glucose-induced ultrafiltration from blood occurs via phase C at the rate of 15 ml/min. The proposed model delineating the phenomenon of concomitant bidirectional transport through PTS is based on a two-phase structure of the interstitium and provides results in agreement with clinical and experimental data.
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- Stachowska-Pietka, J, et al.
(författare)
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Distributed model of peritoneal fluid absorption
- 2006
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Ingår i: American journal of physiology. Heart and circulatory physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 291:4, s. H1862-H1874
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Tidskriftsartikel (refereegranskat)abstract
- The process of water reabsorption from the peritoneal cavity into the surrounding tissue substantially decreases the net ultrafiltration in patients on peritoneal dialysis. The goal of this study was to propose a mathematical model based on data from clinical studies and animal experiments to describe the changes in absorption rate, interstitial hydrostatic pressure, and tissue hydration caused by increased intraperitoneal pressure after the initiation of peritoneal dialysis. The model describes water transport through a deformable, porous tissue after infusion of isotonic solution into the peritoneal cavity. Blood capillary and lymphatic vessels are assumed to be uniformly distributed within the tissue. Starling's law is applied for a description of fluid transport through the capillary wall, and the transport within the interstitium is modeled by Darcy's law. Transport parameters such as interstitial fluid volume ratio, tissue hydraulic conductance, and lymphatic absorption in the tissue are dependent on local interstitial pressure. Numerical simulations show the strong dependence of fluid absorption and tissue hydration on the values of intraperitoneal pressure. Our results predict that in the steady state only ∼20–40% of the fluid that flows into the tissue from the peritoneal cavity is absorbed by the lymphatics situated in the tissue, whereas the larger (60–80%) part of the fluid is absorbed by the blood capillaries.
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- Stachowska-Pietka, J, et al.
(författare)
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Water removal during automated peritoneal dialysis assessed by remote patient monitoring and modelling of peritoneal tissue hydration
- 2021
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1, s. 15589-
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Tidskriftsartikel (refereegranskat)abstract
- Water removal which is a key treatment goal of automated peritoneal dialysis (APD) can be assessed cycle-by-cycle using remote patient monitoring (RPM). We analysed ultrafiltration patterns during night APD following a dry day (APDDD; no daytime fluid exchange) or wet day (APDWD; daytime exchange). Ultrafiltration for each APD exchange were recorded for 16 days using RPM in 14 patients. The distributed model of fluid and solute transport was applied to simulate APD and to explore the impact of changes in peritoneal tissue hydration on ultrafiltration. We found lower ultrafiltration (mL, median [first quartile, third quartile]) during first and second vs. consecutive exchanges in APDDD (−61 [−148, 27], 170 [78, 228] vs. 213 [126, 275] mL; p < 0.001), but not in APDWD (81 [−8, 176], 81 [−4, 192] vs. 115 [4, 219] mL; NS). Simulations in a virtual patient showed that lower ultrafiltration (by 114 mL) was related to increased peritoneal tissue hydration caused by inflow of 187 mL of water during the first APDDD exchange. The observed phenomenon of lower ultrafiltration during initial exchanges of dialysis fluid in patients undergoing APDDD appears to be due to water inflow into the peritoneal tissue, re-establishing a state of increased hydration typical for peritoneal dialysis.
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- Wang, T, et al.
(författare)
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Physiological saline is not a biocompatible peritoneal dialysis solution
- 1999
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Ingår i: The International journal of artificial organs. - : SAGE Publications. - 0391-3988 .- 1724-6040. ; 22:2, s. 88-93
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Tidskriftsartikel (refereegranskat)abstract
- We have previously demonstrated that daily exposure to dialysis fluid results in significantly increased peritoneal lymphatic flow. In this study, we investigated if daily intraperitoneal infusion of saline (isotonic, glucose free) could cause similar changes. Sixteen male SD rats received daily infusion (i.p) of 20 ml saline for ten days (Saline group). Twenty-four hours after the last infusion, a 4 hour dwell study using 25 ml 3.86% glucose dialysis solution with frequent dialysate and blood sampling was done in each rat as well as in rats which did not receive daily infusion (Control, n=8). Radiolabeled human albumin (RISA) was added to the solution as an intraperitoneal volume marker. Radioactivity, glucose, urea, sodium, and potassium were measured for each sample. In a separate study, the RISA absorption to peritoneal tissue was also determined. Results The net ultrafiltration was significantly decreased in the daily infusion group (p<0.05). However, the apparent volume at 3 minutes of the dwell was markedly increased; this was due to a significant increase in the RISA binding (1.5–12.0% in the Saline group vs. 0.45–1.12% in the Control group) to peritoneal tissues as assessed by measurement of RISA recovery at 3 min of the dwell. This resulted in a significant overestimation both of the intraperitoneal volume (IPV) at 3 min and the (apparent) fluid absorption rate (as estimated by the transport of RISA out of peritoneal cavity): 0.087±0.026 ml/min in the Saline group vs. 0.052±0.007 ml/min in the Control group, p<0.001. The direct lymphatic flow as estimated by the clearance of RISA to plasma (which should not be affected by the RISA binding) also increased markedly (0.021±0.005 ml/min in the Saline group vs. 0.008±0.001 ml/min in the control group). There was no significant difference in the D/P values for small solutes (urea, sodium, potassium, urate) and D/D0 for glucose between the two groups. Conclusions 1) Daily infusion of physiological saline into peritoneal cavity may increase the peritoneal lymphatic flow; 2) The significant (apparent) increase in IPV shortly after infusion may suggest increased RISA binding to peritoneal tissues (which may be related to the damage of the tissues, and results in overestimation of the peritoneal fluid absorption rate); 3) Saline is not a biocompatible peritoneal dialysis solution, and should therefore not be used as a control or flush solution.
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