Peritoneal Transport Characteristics of Water, Low-Molecular Weight Solutes and Proteins during Long Term Continuous Ambulatory Peritoneal Dialysis

1986 ◽  
Vol 6 (2) ◽  
pp. 61-65 ◽  
Author(s):  
Raymond T. Krediet ◽  
Elisabeth W. Boeschoten ◽  
Floris M.J. Zuyderhoudt ◽  
Lambertus Arisz
Keyword(s):  
Mass Transfer ◽  
Molecular Weight ◽  
Peritoneal Dialysis ◽  
Surface Area ◽  
Low Molecular Weight ◽  
Glucose Kinetics ◽  
Peritoneal Surface ◽  
Peritoneal Transport ◽  
Peritoneal Permeability

Peritoneal transport of water, low-molecular-weight solutes and proteins was studied on 75 occasions in 38 CAPD patients. Maximal ultrafiltration capacity decreased with time on CAPD, while there was an increase in the number of hypertonic bags used and the peritoneal absorption of glucose. A relationship was found between maximal ultrafiltration capacity and glucose kinetics. The duration of CAPD was longer in the patients with poor ultrafiltration, while they had a faster transport of glucose and creatinine, but not of proteins. In the group as a whole, no obvious changes were found in the mass transfer area coefficients of urea, creatinine and glucose, nor in the clearances of albumin and IgG. In the five patients with severe ultrafiltration loss, we found evidence of either decreased or increased peritoneal solute transport. Contrasting findings in transport of small solutes and proteins may reflect increased effective peritoneal surface area combined with decreased peritoneal permeability.

Determinants of Peritoneal Solute Transport Rates in Newly Started Nondiabetic Peritoneal Dialysis Patients

2004 ◽  
Vol 24 (6) ◽  
pp. 554-561 ◽  
Author(s):  
Sadie van Esch ◽  
Machteld M. Zweers ◽  
Maarten A.M. Jansen ◽  
Dirk R. de Waart ◽  
Jeannette G. van Manen ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Surface Area ◽  
Inflammatory Markers ◽  
Cell Mass ◽  
Mesothelial Cell ◽  
Serum Concentrations ◽  
Peritoneal Surface ◽  
Peritoneal Transport ◽  
Peritoneal Permeability ◽  
Fast Transport

Objective An overrepresentation of a fast peritoneal transport status in new peritoneal dialysis (PD) patients with extensive comorbidity has been reported in some studies. High mass transfer area coefficients (MTACs) of low MW solutes suggest the presence of a large effective peritoneal surface area. The mechanism is unknown. It might include comorbidity, chronic inflammation, or an effect of mesothelial cell mass on peritoneal transport by the production of vasoactive substances. To investigate their relative importance in early PD, peritoneal permeability characteristics in incident PD patients were analyzed for relationships with comorbidity, serum concentrations of inflammatory markers, and products of the mesothelial cells that can be detected in dialysate. Design A cross-sectional study. Setting A university hospital. Methods 46 patients who fulfilled the following inclusion criteria were analyzed: a standard peritoneal permeability analysis (SPA) within 6 months after the start of PD, no peritonitis prior to the SPA, older than 18 years, and without diabetes mellitus as a primary renal disease. The patients were divided into tertiles based on the MTAC creatinine: slow, medium, and fast transport groups. The Davies comorbidity score was used to assess comorbidity. Serum and dialysate samples obtained during the SPA were used to determine hyaluronan, interleukin (IL)-6, vascular endothelial growth factor (VEGF), and cancer antigen 125 (CA125). The dialysate concentrations of these substances were expressed as their dialysate appearance rates. Results No significant differences were present in the three transport groups for comorbidity, serum concentrations of inflammatory markers, or serum VEGF. Interleukin-6 and VEGF concentration attributed to local VEGF production were not different between the tertiles. Levels of VEGF were higher in the medium transport group compared to the slow transport group ( p = 0.02); CA125 was higher in the fast transport group compared to the medium transport group ( p = 0.01). When analyzed as continuous variables, MTAC creatinine was related to VEGF ( r = 0.33, p < 0.05) and CA125 ( r = 0.41, p = 0.03). In linear regression analysis, VEGF influenced the association between CA125 and MTAC creatinine; IL-6 weakened this association only marginally. Conclusion A fast peritoneal transport status in incident nondiabetic PD patients was not related to comorbidity. The relationships found between VEGF, CA125, and MTAC creatinine may suggest a role of VEGF in the regulation of the vascular peritoneal surface area, possibly already before structural abnormalities have developed. Our analyses are consistent with the hypothesis that mesothelial cell mass is an important determinant of the peritoneal transport status in incident nondiabetic PD patients without previous peritonitis. Of the many potential mediators produced by mesothelial cells, VEGF was more important than the inflammation marker IL-6.

The Standard Peritoneal Permeability Analysis in the Rabbit: A Longitudinal Model for Peritoneal Dialysis

1999 ◽  
Vol 19 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Machteld M. Zweers ◽  
Caroline E. Douma ◽  
Dirk R. De Waart ◽  
Anton B. Van Der Wardt ◽  
Marja M. Ho-Dac-Pannekeet ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Peritoneal Dialysis ◽  
Normal Values ◽  
Rabbit Model ◽  
Low Molecular Weight ◽  
Transport Parameters ◽  
Lymphatic Absorption ◽  
Intraindividual Variation ◽  
Peritoneal Transport ◽  
Peritoneal Permeability

Objective The development of an experimental peritoneal dialysis (PD) model in rabbits to investigate peritoneal transport characteristics during a longitudinal follow-up and to assess normal values of these peritoneal transport parameters. Design Peritoneal transport parameters were determined in conscious, unrestrained rabbits by standard peritoneal permeability analysis adjusted for rabbits (SPAR). In this test a 1-hour dwell with 3.86% glucose dialysate is used. Dextran 70 (1 g/L) was added to the dialysate to allow calculation of fluid kinetics. Dialysate samples were taken before, 10, and 40 minutes after instillation and at the end of the dwell. Blood was drawn at the end of the dwell. Experimental Animals Eighteen female New Zealand White rabbits (2565 g) were included for catheter implantation. SPARs were performed in 15 animals; the other 3 were excluded due to complications. Main Outcome The mass transfer area coefficients (MTACs) of the low molecular weight solutes urea (MTACurea) and creatinine (MTACcr) were calculated. The clearances of albumin (Clalb) and IgG (ClIgG), glucose absorption, and fluid transport were computed. Coefficients of intraindividual variation (Vc) were calculated for these parameters. Results The main complications were catheter obstruction and/or dislocation. Five rabbits underwent uncomplicated PD during a 4-week period. Fifteen SPARs in 15 stable rabbits were performed and analyzed to obtain normal values. Means and standard deviations of the transport parameters were as follows: MTACurea 2.24 ± 0.57 mL/min, MTACcr 1.61 ± 0.30 mL/min, Clalb 52.9 ± 17.2 μL/min, ClIgG 44.5 ± 22.9 μL/min. The transcapillary ultrafiltration rate was 0.66 ± 0.13 mL/min and the lymphatic absorption rate 0.47 ± 0.26 mL/min. The parameters of solute transport were upscaled to those in humans using two different methods. MTACs of low molecular weight solutes in rabbits and patients were of the same order of magnitude, but the clearance of albumin was approximately four times higher in rabbits than in patients, and that of IgG eight times. In all rabbits sieving of sodium was observed. The dialysate/plasma (D/P) of sodium decreased to a minimum at 40 min ( p < 0.003 vs the initial value), followed by a rise to 60 min. The minimal value was 0.884 ± 0.002. The coefficients of variation calculated on 7 rabbits that underwent two or more SPARs were similar to those assessed from the patient data. This indicates stability of the model and reproducibility of the SPAR. Conclusion The conscious rabbit model for PD can be used for repeated studies on peritoneal transport.

Impact of ACE Inhibitors and AII Receptor Blockers on Peritoneal Membrane Transport Characteristics in Long-Term Peritoneal Dialysis Patients

2007 ◽  
Vol 27 (4) ◽  
pp. 446-453 ◽  
Author(s):  
Inna Kolesnyk ◽  
Friedo W. Dekker ◽  
Marlies Noordzij ◽  
Saskia le Cessie ◽  
Dirk G. Struijk ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Peritoneal Dialysis ◽  
Solute Transport ◽  
Animal Studies ◽  
Control Group ◽  
Peritoneal Transport ◽  
Ultrafiltration Failure ◽  
Significant Difference

Background Long-term peritoneal dialysis (PD) may lead to peritoneal fibrosis and ultrafiltration failure. The latter occurs due to high solute transport rates and diabetiform peritoneal sclerosis. Angiotensin-II (AII) is known to be a growth factor in the development of fibrosis and a number of animal studies have shown it likely that inhibiting the effects of AII by angiotensin-converting enzyme (ACE) or angiotensin receptor blocker (ARB) will attenuate these complications. Objective To investigate the effects of ACE/AII inhibitors in long-term PD patients. Patients and Setting We analyzed data from 66 patients treated with PD therapy at our center for at least 2 years, during which time at least 2 standard peritoneal permeability analyses (SPAs) were performed. 36 patients were treated with ACE/AII inhibitors (ACE/ARB group); the other 30 received none of the above drugs during the entire follow-up (control group). The two groups were compared with respect to changes in peritoneal transport over the follow-up time. Results A significant difference in time course of peritoneal transport was found between the 2 groups: in the ACE/ARB group, small solute transport had decreased, while it had increased in the control group. This finding was confirmed by analysis using mixed model for repeated measures. The value of mass transfer area coefficient of creatinine was influenced by the duration of PD therapy ( p = 0.017) and this interaction was different with respect to use of ACE/AII inhibitors ( p = 0.037). The trend was not found in protein clearances or fluid kinetics. Conclusion Our findings suggest that ACE/AII inhibition is likely to prevent the increase in mass transfer area coefficients that occurs in long-term PD, which is in line with results of experimental animal studies.

Mass Transfer Area Coefficients in Children

1994 ◽  
Vol 14 (1) ◽  
pp. 30-33 ◽  
Author(s):  
Denis F. Geary ◽  
Elizabeth A. Harvey ◽  
J. Williamson Balfe
Keyword(s):  
Mass Transfer ◽  
Body Weight ◽  
Peritoneal Dialysis ◽  
Solute Transport ◽  
Surface Area ◽  
Peritoneal Surface ◽  
Unit Body Weight ◽  
Rapid Transport ◽  
Sick Children

Objective Measurement of mass transfer area coefficients (MTAC) in children of different sizes to determine if solute transport varies with age and to compare with published adult values. Design Mass transfer area coefficients calculated from prospectively collected data in 28 selected patients. Participants All children starting maintenance peritoneal dialysis at the Hospital for Sick Children. Selected patients were also studied if hospitalized for unrelated reasons. Results Mean MTAC values for creatinine and glucose were 4.0 and 4.5 mL/min, respectively, both considerably lower than adult values. When scaled per 70 kg body weight, these results were greater, and when scaled per 1.73 m2 surface area, they were lower than reported adult values. The MTAC/kg body weight was inversely correlated to age. Conclusions Solute transport in children is directly related to age and does not approach adult values until later childhood. However, more rapid transport per unit body weight is observed in children and may reflect an increased effective peritoneal surface area.

Icodextrin'S Effects on Peritoneal Transport

1997 ◽  
Vol 17 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Raymond T. Krediet ◽  
Marja M. Ho-Dac-Pannekeet ◽  
Alexander L.T. Imholz
Keyword(s):  
Molecular Weight ◽  
Surface Area ◽  
Serum Proteins ◽  
Academic Medical Center ◽  
Convective Transport ◽  
Low Molecular Weight ◽  
Β2 Microglobulin ◽  
Peritoneal Surface ◽  
Ultrafiltration Failure ◽  
Small Pore

Objective To give a survey of the principles of peritoneal fluid transport in general, followed by an analysis of the effects of icodextrin on the transport of fluid and solutes. Design A review of the literature and of data on the effects of icodextrin in continuous ambulatory peritoneal dialysis (CAPD) patients at the Academic Medical Center, Amsterdam. Results Icodextrin had no effect on the mass transfer area coefficients of low molecular weight solutes. Also no effect was found on the clearances of albumin and larger serum proteins. Due to convective transport, the clearance of β2-microglobulin was greater with icodextrin than with glucose solutions. Icodextrin was especially superior to glucose in the induction of net ultrafiltration during long dwells, during peritonitis, and in patients with ultrafiltration failure caused by a large effective peritoneal surface area. Conclusion Icodextrin has no effect on the permeability characteristics of the peritoneal membrane, but increases convective flow through the small-pore system. As a result, the peritoneal clearance of β2-microglobulin is higher than with glucose-based solutions.lcodextrin is especially indicated for long dwells and in patients with impaired ultrafiltration caused by a large peritoneal surface area, leading to high transport rates of low molecular weight solutes.

scholarly journals Role of the liver in small-solute transport during peritoneal dialysis.

1994 ◽  
Vol 5 (1) ◽  
pp. 116-120
Author(s):  
M F Flessner ◽  
R L Dedrick
Keyword(s):  
Mass Transfer ◽  
Peritoneal Dialysis ◽  
Surface Area ◽  
Peritoneal Cavity ◽  
Distributed Model ◽  
Blood Capillaries ◽  
Peritoneal Surface ◽  
Small Solute ◽  
Good Agreement

Peritoneal dialysis (PD) is dependent on the transport of water and solutes from the blood capillaries within the tissues that surround the peritoneal cavity. Because of their large blood supply and surface area, the viscera have been considered the most important tissues for PD transport. In animals, however, removal of the gastrointestinal tract decreases PD small-solute mass transfer by only 10 to 27%. To investigate the theoretical basis for these observations, a distributed model of peritoneal transport was extended to take into account the transport characteristics of four tissue groups that surround the cavity: the liver, the hollow viscera, the abdominal wall, and the diaphragm. The mass transfer-area coefficient (MTAC) of sucrose for each tissue was calculated from the following: MTAC = ([D(pa)]0.5)A, where D is the effective solute interstitial diffusivity, pa is the solute transcapillary permeability-area per unit tissue volume, and A is the apparent peritoneal surface area of the tissue. Our results for the adult human predict that the MTAC for the liver is comparable to that of all of the other viscera and makes up 43% of the total MTAC for the peritoneal cavity. The predicted MTAC is 4 cm3/min (plasma) or 6 cm3/min (blood), in good agreement with published values. It is concluded that the liver is responsible for a major portion of the small-solute MTAC. This also explains the earlier observations in eviscerated animals whose PD transport was likely preserved by intact livers.

Antithrombotic Therapy for DVT/PE

1997 ◽  
Vol 17 (03) ◽  
pp. 161-162
Author(s):  
Thomas Hyers
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Oral Anticoagulants ◽  
Cost Effective ◽  
Therapeutic Agents ◽  
Great Promise ◽  
Term Therapy ◽  
Low Molecular Weight ◽  
Long Term Therapy

SummaryProblems with unfractionated heparin as an antithrombotic have led to the development of new therapeutic agents. Of these, low molecular weight heparin shows great promise and has led to out-patient therapy of DVT/PE in selected patients. Oral anticoagulants remain the choice for long-term therapy. More cost-effective ways to give oral anticoagulants are needed.

Self-Managed Long-Term Low-Molecular-Weight Heparin Therapy: The Balance of Benefits and Harms

2007 ◽  
Vol 120 (1) ◽  
pp. 72-82.e3 ◽  
Author(s):  
Russell D. Hull ◽  
Graham F. Pineo ◽  
Rollin F. Brant ◽  
Andrew F. Mah ◽  
Natasha Burke ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Heparin Therapy ◽  
Low Molecular Weight
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