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Abstract
Objective The present study aimed to develop an animal model of chronic peritoneal exposure that directly links transport with the tissue involved. Methods Daily, rats were intraperitoneally infused through subcutaneous ports with 20 mL of these solutions: isotonic Krebs (K), K + 2.5% mannitol (M), K + 2.5% N-acetylglucosamine (NAG). Controls included catheter-only (CC) and age-control rats (AC). After 2 months, each rat was anesthetized and a plastic chamber was affixed to the abdominal wall serosa to isolate a portion of the peritoneum for transport studies. In the first 90 minutes, a hypertonic solution (approximately 500 mosm/kg) containing 14C-mannitol was placed in chamber. The volume and 14C concentration were measured to determine the rate of osmotic flux (flow/Areachamber) into the chamber and the flux of mannitol from the chamber to the tissue. At 90 minutes, fluorescein isothiocyanate conjugate (FITC)–albumin was given intravenously. The rate of appearance of that substance in the chamber was measured over a period of 180 minutes and divided by Areachamber to determine the average flux. After the rat was humanely killed, the tissue under the chamber was collected for analysis of its hyaluronan concentration ([HA]). Results All data are given as mean ± standard error: Group Osmotic (μL/cm2) Flux per hour Mannitol (/cm2) Albumin (/cm2) [HA] (μg/g dry) AC 69.9±14.0 0.043±0.004 0.0114±0.0012 1247±136 CC 65.5±8.0 0.040±0.013 0.0105±0.0027 1360±157 K 47.0±11.5 0.067±0.015 0.0116±0.0027 1134±160 M 101±20 0.044±0.017 0.0300±0.0120 1146±157 NAG 72.6±11.4 0.052±0.006 0.0188±0.0144 1240±157 Conclusions In the present pilot study, no significant correlations were observed, but the number of animals in each group was small ( n = 3 – 4). Nevertheless, the results demonstrate the ability of the chamber technique to determine transperitoneal transport of water, small solutes, and protein, and to link those values directly to the structure of the tissue lying below the chamber. Thus, chronic treatment can be directly correlated with peritoneal structure and transport function.
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Flessner M, Henegar J, Bigler S, Genous L. Is the Peritoneum a Significant Transport Barrier in Peritoneal Dialysis? Perit Dial Int 2020. [DOI: 10.1177/089686080302300605] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
ObjectivesThe anatomic peritoneum is often considered equivalent to the barrier between the dialysate and the blood, and is also called “the peritoneal membrane.” Our hypothesis is that the normal peritoneum is not a significant barrier to solute or water flow. The goal of this study was to explore the effects of alteration of the anatomic peritoneum on the transperitoneal transport of water and solute.DesignIn vivo transport experiments were carried out in control and treated rats. Treatments consisted of frequent mixing of the peritoneal solution versus no mixing, drying the peritoneum prior to the experiment, or selective removal of the entire peritoneum. Transport experiments were carried out via a plastic chamber affixed to the parietal peritoneum. After measuring solute transport or osmotically induced filtration, the tissue underlying the chamber was collected and stained for histology.ResultsMixing the chamber solution every 5 minutes versus no mixing over 90 minutes did not result in a significant change in the mass transfer coefficient for mannitol (MTCmannitol, n = 14, p > 0.25). Drying the peritoneum prior to the transport experiment did not significantly alter the MTC of albumin or mannitol ( n = 17, p > 0.6; n = 19, p > 0.1, respectively). Manual drying did not remove or significantly alter the apparent peritoneal coating on the surface of the mesothelium. Removal of the entire peritoneum did not significantly alter the osmotically induced volume flux from the tissue, nor did it change the MTCmannitol( n = 9, p > 0.9; n = 9, p > 0.4, respectively).ConclusionsMixing of the solution directly over the tissue, manual drying of the peritoneum, or removal of the entire peritoneum does not result in significant alterations in transport. We conclude that the anatomic peritoneum is relatively unimportant as a physical transport barrier in peritoneal dialysis.
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Affiliation(s)
- Michael Flessner
- Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Jeffrey Henegar
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Steven Bigler
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Lori Genous
- Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
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Breton E, Choquet P, Bergua L, Barthelmebs M, Haraldsson B, Helwig JJ, Constantinesco A, Fischbach M. In Vivo Peritoneal Surface Area Measurement in Rats by Micro-Computed Tomography (μCT). Perit Dial Int 2020. [DOI: 10.1177/089686080802800216] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Peritoneal dialysis (PD) uses the dynamic dialysis properties of the peritoneal membrane. The fraction of the anatomic peritoneal surface area (PSA) recruited is of importance for maximizing exchanges and is potentially impacted by parameters such as fill volume.We describe an in vivo assessment of the contact surface area by micro-computed tomography (μCT) using an iodinated contrast medium added to the PD fluid, a contrast agent presumed without surfactant property. In the isotropic volume (reconstructed voxel size 186 μm x 186 μm x 186 μm), the iodinated PD fluid is automatically selected, thanks to its contrast difference with soft tissues, and its surface area is computed. The method was first tested on phantoms showing the ability to select the PD fluid volume and to measure its surface area. In vivo experiments in rat consisted of μCT acquisition of rat abdomen directly after intraperitoneal administration (10 mL/100 g rat body weight) of a dialysis fluid containing 10% by volume iodinated contrast agent. Fluorescein isothiocyanate albumin was used as dilution marker.We found a strong linear relationship ( R2= 0.98) between recruited PSA (cm2) and rat weight (g) in the range of 235 to 435 g: recruited PSA = (1.61 weight + 40.5) cm2. Applying μCT with a fill volume of 10 mL/100 g rat body weight, the in vivo measured PSA was in the order of magnitude of the ex vivo anatomic PSA as determined by Kuzlan's formula, considered in most instances as the maximal surface area that can be recruited by PD fluid.This new methodology was the first to give an in vivo high-resolution isotropic three-dimensional (3-D) determination of the PSA in contact with dialysate. Its sensitivity allows us to take into account the recruitment of fine 3-D structures of the PSA membrane that were not accessible to previous 2-D-based imaging methodologies. Its in vivo application also integrates the physiological natural tensile stress of tissues.
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Affiliation(s)
- Elodie Breton
- Department of Biophysics and Nuclear Medicineand University Hospital, Strasbourg, France
| | - Philippe Choquet
- Department of Biophysics and Nuclear Medicineand University Hospital, Strasbourg, France
| | - Laure Bergua
- Nephrology Dialysis Transplantation Children's Unit, and University Hospital, Strasbourg, France
| | | | - Börje Haraldsson
- Department of Nephrology and Physiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Jean-Jacques Helwig
- INSERM Unit 727, University Louis Pasteur Medical School, Strasbourg, France
| | - André Constantinesco
- Department of Biophysics and Nuclear Medicineand University Hospital, Strasbourg, France
| | - Michel Fischbach
- Nephrology Dialysis Transplantation Children's Unit, and University Hospital, Strasbourg, France
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Physiological Properties of the Peritoneum in an Adult Peritoneal Dialysis Population over a Three-Year Period. Perit Dial Int 2020. [DOI: 10.1177/089686080602600413] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objectives To describe the physiological properties of the peritoneal membrane in adult patients treated with peritoneal dialysis (PD) and to analyze the effects of patient characteristics and time. Design Observational study. Setting Department of Nephrology at the Sahlgrenska University Hospital. Method Peritoneal function was analyzed by the Personal Dialysis Capacity (PDC) test, based on the three-pore theory of capillary transport. The functional PDC variables are absorption, large-pore flow, and the area parameter (A0/Δx), which determines the diffusion of small solutes. The ultra-filtration (UF) coefficient is determined mainly by A0/Δx. Patients All patients ( n = 280) who had at least one PDC test done between September 1990 and August 1999. Results In 249 patients examined soon after start of PD, area was 19000 (SD 7100) cm2/cm/1.73 m2, large-pore flow 0.112 (SD 0.052) mL/min/1.73 m2, and the UF coefficient 0.071 (SD 0.032) mL/minute/mmHg/1.73 m2. Absorption was 1.54 (SD +2.64, –0.97) mL/min/1.73 m2. Large-pore flow was greater in patients with severe comorbidity than in patients with fewer comorbid conditions. Elderly patients had a lower UF coefficient than did younger patients ( p < 0.05). Repeated PDC tests were performed in 208 patients during a mean observation time of 18.4 months. There was a slight increase in the slope of the area-versus-time curve of 54 cm2/cm/1.73 m2 per month (approximately 10% after 3 years, p < 0.01); all other parameters remained constant. Conclusion Patient characteristics have an impact on peritoneal performance already at the start of dialysis. Peritoneal function can remain essentially stable during medium long-term PD.
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Zakaria ER, Joseph B, Hamidi M, Zeeshan M, Algamal A, Sartaj F, Althani M, Fadl T, Madan D. Glycine improves peritoneal vasoreactivity to dialysis solutions in the elderly. Qatar Med J 2019; 2019:19. [PMID: 31903325 PMCID: PMC6929513 DOI: 10.5339/qmj.2019.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/03/2019] [Indexed: 11/23/2022] Open
Abstract
Background: Peritoneal dialysis solution (PDS) dilates peritoneal microvessels predominantly by the activation of the endothelial nitric oxide (NO) pathway. We made an incidental observation of decreased PDS-induced, NO-dependent peritoneal microvascular vasoreactivity in elderly rats naïve to PDS exposure. We hypothesized that this subordinate NO-mediated peritoneal microvascular vasoreactivity is caused by increased oxidative stress in the aged endothelium, which compromises NO bioavailability in the elderly, and that peritoneal microvascular vasoreactivity can be improved by the supplementation of antioxidant glycine to PDS. Methods: We studied PDS-mediated vasoreactivity of four intestinal visceral arterioles of different orders by in vivo intravital microscopy in weaned, adult, and elderly rats to (i) confirm subordinate vasoreactivity to PDS in elderly rats; (ii) restore vasoreactivity by glycine supplementation; and (iii) establish age as an independent risk factor for endothelial cell dysfunction. Results: In a crossover series, peritoneal microvascular vasoreactivity to PDS exposure was remarkably decreased in elderly rats. This subordinate vasoreactivity was completely restored by the supplementation of glycine to PDS. In a separate series, we assessed in situ endothelial cell function in weaned and adult rats using the cumulative acetylcholine concentration–response curves. Unlike the adults, the weaned rats demonstrated remarkable sensitivity and reactivity to cumulative acetylcholine concentrations, suggesting the dependency of endothelial cell function on age. Conclusion: Aging is an independent risk factor for peritoneal microvascular endothelial cell dysfunction. Endothelial function in the elderly can be recovered by reinforcing the bioavailability of endothelial-derived NO through glycine. Dietary glycine supplementation is a potential therapeutic strategy to decrease the burden of oxidative stress on the aged endothelium.
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Affiliation(s)
- El Rasheid Zakaria
- The University of Arizona, Division of Trauma, Critical Care, Burns & Emergency Surgery, Tucson, AZ 85721, USA
| | - Bellal Joseph
- The University of Arizona, Division of Trauma, Critical Care, Burns & Emergency Surgery, Tucson, AZ 85721, USA
| | - Mohammad Hamidi
- The University of Arizona, Division of Trauma, Critical Care, Burns & Emergency Surgery, Tucson, AZ 85721, USA
| | - Muhammad Zeeshan
- The University of Arizona, Division of Trauma, Critical Care, Burns & Emergency Surgery, Tucson, AZ 85721, USA
| | - Abdelrahman Algamal
- Qatar University, Biomedical Research Center & College of Arts and Health Sciences, P.O. Box 2713, Doha, Qatar
| | - Faheem Sartaj
- Qatar University, Biomedical Research Center & College of Arts and Health Sciences, P.O. Box 2713, Doha, Qatar
| | - Maha Althani
- Qatar University, Biomedical Research Center & College of Arts and Health Sciences, P.O. Box 2713, Doha, Qatar
| | - Tassnim Fadl
- Qatar University, Biomedical Research Center & College of Arts and Health Sciences, P.O. Box 2713, Doha, Qatar
| | - Dana Madan
- Qatar University, Biomedical Research Center & College of Arts and Health Sciences, P.O. Box 2713, Doha, Qatar
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Bartosova M, Rudolf A, Pichl S, Schmidt K, Okun JG, Straub BK, Rutkowski R, Witowski J, Schmitt CP. Increased storage and secretion of phosphatidylcholines by senescent human peritoneal mesothelial cells. Clin Exp Nephrol 2015; 20:544-551. [PMID: 26527208 DOI: 10.1007/s10157-015-1192-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/24/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND/AIMS Human peritoneal mesothelial cells (HPMC) secrete phosphatidylcholines (PC) which form a lipid bilayer lining the peritoneum. They prevent frictions and adhesions and act as a barrier to the transport of water-soluble solutes while permitting water flux. PC may play an essential role in peritoneal integrity and function, the role of PD induced HPMC senescence on PC homeostasis, however, is unknown. METHODS HPMC cell lines were isolated from four non-uremic patients. Expression of the three PC synthesis genes (rt-PCR), and cellular storage and secretion of PC (ESI-mass-spectrometry) were analyzed in young and senescent HPMC (>Hayflick-limit). RESULTS Senescent cells displayed significantly altered morphology; flow cytometry demonstrated extensive staining for senescence-associated beta galactosidase. Nine different PC were detected in HPMC with palmitoyl-myristoyl phosphatidylcholine (PMPC) being most abundant. In senescent HPMC mRNA expression of the three key PC synthesis genes was 1.5-, 2.4- and 6-fold increased as compared to young HPMC, with the latter, phosphatidylcholine cytidylyltransferase, being rate limiting. Intracellular storage of the nine PC was 75-450 % higher in senescent vs. young HPMC, PC secretion rates were 100-300 % higher. Intracellular PC concentrations were not correlated with the PC secretion rates. Electron microscopy demonstrated lamellar bodies, the primary storage site of PC, in senescent but not in young cells. CONCLUSION Senescent HPMC store and secrete substantially more PC than young cells. Our findings indicate a novel protective mechanism, which should counteract peritoneal damage induced by chronic exposure to PD fluids.
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Affiliation(s)
- Maria Bartosova
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | | | - Sebastian Pichl
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Kathrin Schmidt
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Jürgen G Okun
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Beate K Straub
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
| | | | | | - Claus P Schmitt
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany.
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Mesure par μTDM et dilution de nanocolloïdes-99mTc de la surface péritonéale chez le rat insuffisant rénal au cours d’une expérience de dialyse péritonéale. Ing Rech Biomed 2009. [DOI: 10.1016/j.irbm.2009.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Albanese AM, Albanese EF, Miño JH, Gómez E, Gómez M, Zandomeni M, Merlo AB. Peritoneal surface area: measurements of 40 structures covered by peritoneum: correlation between total peritoneal surface area and the surface calculated by formulas. Surg Radiol Anat 2009; 31:369-77. [DOI: 10.1007/s00276-008-0456-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 12/10/2008] [Indexed: 10/21/2022]
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9
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Peritoneal membrane recruitment in rats: a micro-computerized tomography (muCT) study. Pediatr Nephrol 2008; 23:2179-84. [PMID: 18636278 DOI: 10.1007/s00467-008-0904-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Revised: 05/08/2008] [Accepted: 05/09/2008] [Indexed: 10/21/2022]
Abstract
The peritoneal contact surface area (PCSA), which represents the area parameter in the mass transfer area coefficient (MTAC), is a crucial marker in the evaluation of peritoneal dialysis effectiveness. However, the capacity to recruit a larger PCSA has only been rarely demonstrated in vivo and, in most cases, changes in MTAC are interpreted as permeability changes and not as surface area variations. Here, we report the use of micro-computerized tomography (muCT) for the measurement of PCSA changes to various fill volumes. Using this three-dimensional imaging method, PCSA was measured in vivo in 26 healthy Wistar rats receiving intraperitoneally increasing fill volumes of peritoneal dialysis solutions: 5 mL (group 1, n = 8), 10 mL (group 2, n = 8) and 15 mL (group 3, n = 10) per 100 g of body weight. A non-ionic iodinated contrast agent was added to the dialysis solution in order to distinguish the intraperitoneal dialysis solutions from soft tissues. The normalized PCSA/weight ratio (cm(2)/g) increased with fill volume: 1.12 +/- 0.10 cm(2)/g (range 0.98-1.25) in group 1; 1.74 +/- 0.08 cm(2)/g (range 1.64-1.87) in group 2; 2.13 +/- 0.09 cm(2)/g(range 1.90-2.30) in group 3. With this muCT method, PCSA recruited in vivo with a 10 mL/100 g fill volume was in the range 94-107%) of ex vivo total peritoneal surface area (evPSA), as calculated with the Kuzlan's formula. With a 15 mL/100 g fill volume, the in vivo-measured PCSA, the exchange surface area, surpassed the evPSA (range 113-139%).
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10
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Comparison of intravenous and intraperitoneal [123I]IBZM injection for dopamine D2 receptor imaging in mice. Nucl Med Biol 2008; 35:543-8. [DOI: 10.1016/j.nucmedbio.2008.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 03/10/2008] [Accepted: 03/17/2008] [Indexed: 11/18/2022]
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11
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Flessner MF, Credit K, Henderson K, Vanpelt HM, Potter R, He Z, Henegar J, Robert B. Peritoneal changes after exposure to sterile solutions by catheter. J Am Soc Nephrol 2007; 18:2294-302. [PMID: 17599969 DOI: 10.1681/asn.2006121417] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Most current animal models that are used to study effects of long-term peritoneal exposure to dialysis solutions use an indwelling catheter for daily injections. It was hypothesized that the presence of a foreign body in the peritoneal cavity (PC) might alter the inflammatory response to the solutions and that the response would depend on exposure duration. For addressing these, long-term injections were carried out for 2 to 8 wk in 90 Sprague-Dawley rats: 40 via a subcutaneous port connected to a silicone catheter tunneled to the PC, 40 via direct needle injection, and 10 noninjected, age-control rats. Daily volumes were 30 to 40 ml of filter-sterilized, bicarbonate-buffered solutions that contained 4% dextrose. After 2, 4, 6, and 8 wk, anesthetized rats underwent transport experiments with a chamber affixed to the abdominal wall to determine mass transfer coefficients of mannitol (MTC(mannitol)) and albumin (MTC(BSA)), osmotic filtration flux (J(osm)), and hydrostatic pressure-driven flux. After the rats were killed, tissues were collected for measurement of peritoneal thickness, vascular density, and immunohistochemical staining. ANOVA demonstrated significant (P < 0.01) differences in thickness, vessel density, MTC(mannitol), and MTC(BSA) among the groups at the various time intervals and in overall means. Differences among the groups were less pronounced for hydrostatic pressure-driven flux and J(osm). Vessel density, MTC(mannitol), MTC(BSA), and J(osm) were dependent on injection duration (P < 0.01). There were marked differences between the needle injection and catheter injection groups at various intervals in the expression of three cytokines. It is concluded that the histologic and functional response depends on the duration of injection with animals that are exposed for as little as 2 wk demonstrating alterations. These findings confirm the hypothesis that the presence of a PC catheter increases inflammatory response to sterile solutions as evidenced by the structural and functional changes in the peritoneal barrier.
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Affiliation(s)
- Michael F Flessner
- Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA.
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Flessner MF, Credit K, Li X, Tanksley J. Similitude of transperitoneal permeability in different rodent species. Am J Physiol Renal Physiol 2007; 292:F495-9. [PMID: 16849694 DOI: 10.1152/ajprenal.00169.2006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Transgenic mice facilitate mechanistic studies of altered peritoneal transport, but the majority of transport studies have been carried out in rats. We hypothesized that mouse transport parameters, normalized to the peritoneal contact area, would be similar to those of the rat. To address this, we affixed small (∼10-mm diameter) plastic chambers to the serosa of the abdominal wall of anesthetized CD1 and C57BL mice. The chamber constrained transfer across the area of the chamber base and facilitated mixing, volumetric, and concentration measurements vs. time for mannitol, serum albumin, and osmotic and hydrostatic pressure-driven convection. The mass transfer coefficient of mannitol (MTCM) and of serum albumin (MTCBSA), hydrostatic pressure-driven flux ( JP), and osmotic filtration ( Josm) were calculated from the time-dependent volume and concentration data. The units of all parameters (μl·min−1·cm−2) were compared with previously derived parameters from SD rats with a one-way ANOVA. Results indicated small but significant differences in MTCBSA(x102): CD1, 9.72 ± 1.97, n = 6; C57BL, 7.13 ± 1.52, n = 10; rat, 12.5 ± 1.6, n = 17 ( P = 0.03). ANOVAs of all other parameters were not significant and confirmed our hypothesis: MTCM(CD1, 3.20 ± 0.38, n = 7; C57BL, 2.34 ± 0.41, n = 6; rat, 2.72 ± 0.23 n = 19), JP(CD1, 0.77 ± 0.15, n = 10; C57BL, 0.33 ± 0.13, n = 15; rat, 0.51 ± 0.16, n = 9), or Josm(CD1, 0.92 ± 0.35, n = 6; C57BL, 0.49 ± 0.35, n = 6; rat 1.72 ± 0.35, n = 6). We conclude that elimination of the variable peritoneal transfer area normalizes calculated transport characteristics and facilitates comparison between species.
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Affiliation(s)
- Michael F Flessner
- Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
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Flessner MF, Choi J, Vanpelt H, He Z, Credit K, Henegar J, Hughson M. Correlating structure with solute and water transport in a chronic model of peritoneal inflammation. Am J Physiol Renal Physiol 2005; 290:F232-40. [PMID: 16118393 DOI: 10.1152/ajprenal.00211.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To study the process of chronic peritoneal inflammation from sterile solutions, we established an animal model to link structural changes with solute and water transport. Filtered solutions containing 4% N-acetylglucosamine (NAG) or 4% glucose (G) were injected intraperitoneally daily in 200- to 300-g rats and compared with controls (C). After 2 mo, each animal underwent transport studies using a chamber affixed to the parietal peritoneum to determine small-solute and protein mass transfer, osmotic filtration, and hydraulic flow. After euthanasia, parietal tissues were sampled for histological analysis, which demonstrated significant differences in peritoneal thickness (microm; C, 42.6 +/- 7.5; G, 80.4 +/- 22.3; NAG, 450 +/- 104; P < 0.05). Staining for VEGF correlated with CD-31 vessel counts (no./mm2: C, 53.1 +/- 16.1; G, 166 +/- 32; NAG, 183 +/- 32; P < 0.05). Tissue analysis showed treatment effects on tissue hyaluronan (micro/g: C, 962 +/- 73; G, 1,169 +/- 69; NAG, 1,428 +/- 69; P < 0.05) and collagen (microg/g: C, 56.9 +/- 12.0; G, 107 +/- 12; NAG, 97.6 +/- 11.4; P < 0.05) but not sulfated glycosaminoglycan. Transport experiments revealed no significant differences in mannitol transfer or osmotic flow. Changes were seen in hydrostatic pressure-driven flux (microl x min(-1) x cm(-2): C, 0.676 +/- 0.133; G, 0.317 +/- 0.124; NAG, 0.284 +/- 0.117; P < 0.05) and albumin transfer (microl x min(-1) x cm(-2): C, 0.331 +/- 0.028; G, 0.286 +/- 0.026; NAG, 0.229 +/- 0.025; P < 0.04). We conclude that alteration of the interstitial matrix correlates with diminished hydraulic conductivity and macromolecular transport.
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Affiliation(s)
- Michael F Flessner
- Nephrology Div., Dept. of Medicine, Univ. of Mississippi Medical Ctr., 2500 North State St., Jackson, MS 39216-4505, USA.
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Abstract
The peritoneal cavity is important in clinical medicine because of its use as a portal of entry for drugs utilized in regional chemotherapy and as a means of dialysis for anephric patients. The barrier between the therapeutic solution in the cavity and the plasma does not correspond to the classic semipermeable membrane but instead is a complex structure of cells, extracellular matrix, and blood microvessels in the surrounding tissue. New research on the nature of the capillary barrier and on the orderly array of extracellular matrix molecules has provided insights into the physiological basis of osmosis and the alterations in transport that result from infusion of large volumes of fluid. The anatomic peritoneum is highly permeable to water, small solutes, and proteins and therefore is not a physical barrier. However, the cells of the mesothelium play an essential role in the immune response in the cavity and produce cytokines and chemokines in response to contact with noncompatible solutions. The process of inflammation, which depends on the interaction of mesothelial, interstitial, and endothelial cells, ultimately leads to angiogenesis and fibrosis and the functional alteration of the barrier. New animal models, such as the transgenic mouse, will accelerate the discovery of methods to preserve the functional peritoneal barrier.
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Affiliation(s)
- Michael F Flessner
- Dept. of Medicine/Nephrology, Univ. of Mississippi Medical Ctr., 2500 North State St., Jackson, MS 39216-4505, USA.
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Fischbach M, Terzic J, Chauvé S, Laugel V, Muller A, Haraldsson B. Effect of peritoneal dialysis fluid composition on peritoneal area available for exchange in children. Nephrol Dial Transplant 2004; 19:925-32. [PMID: 15031351 DOI: 10.1093/ndt/gfg518] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Although conventional peritoneal dialysis fluids (PDFs), such as Dianeal, are non-physiological in composition, new PDFs including Physioneal have a more neutral pH, are at least partially buffered with bicarbonate and, most importantly, contain low concentrations of glucose degradation products (GDPs). METHODS To evaluate the impact of new PDFs in childcare, we performed a comparative crossover study with Dianeal and Physioneal. We examined both intraperitoneal pressure (IPP), which partly reflects pain induction, and the total pore area available for exchange, which indicates the number of capillaries perfused in the peritoneal membrane at any given moment and therefore partly reflects peritoneal dialysis capacity. The IPP was determined after inflow of 1000 ml/m(2) body surface area (BSA) of dialysate (intraperitoneal volume; IPV). The steady-state unrestricted area over diffusion distance (A(0)/ triangle up x, in cm(2)/cm per 1.73 m(2) BSA) was calculated from the three-pore theory. Six children were enrolled in the study. On the first day, two consecutive peritoneal equilibration tests of 90 min each were performed using first Dianeal and then Physioneal. On the second study day, the procedure was repeated with the fluids given in the opposite order. RESULTS The mean IPP normalized to IPV (ml/m(2)) was significantly higher for Dianeal (9.5 +/- 0.9 cm/1000 ml/m(2)) than for Physioneal (7.9 +/- 1.2 cm/1000 ml/m(2), P < 0.01). The mean A(0)/ triangle up x was 17 +/- 4% larger with Dianeal (36 095 +/- 2009 cm(2)/cm per 1.73 m(2)) than with Physioneal (31 780 +/- 2185 cm(2)/cm per 1.73 m(2), P < 0.001; based on 24 data pairs). CONCLUSIONS These pilot study results suggest a higher biocompatibility for Physioneal than for Dianeal. Less inflow pain associated with Physioneal induced a lower IPP reflecting enhanced fill volume tolerance, and the lower A(0)/ triangle up x reflected less capillary recruitment. Taken together, these results suggest that the new more biocompatible PDFs will improve peritoneal dialysis therapy, although this conclusion will require verification in extended clinical trials.
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Affiliation(s)
- Michel Fischbach
- Nephrology Dialysis Transplantation Children's Unit, Hôpital de Hautepierre, Avenue Molière, 67098 Strasbourg, France.
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Chagnac A, Herskovitz P, Ori Y, Weinstein T, Hirsh J, Katz M, Gafter U. Effect of increased dialysate volume on peritoneal surface area among peritoneal dialysis patients. J Am Soc Nephrol 2002; 13:2554-9. [PMID: 12239245 DOI: 10.1097/01.asn.0000026492.83560.81] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Large dialysate volumes are often required to increase solute clearance for peritoneal dialysis patients. The resulting increase in solute clearance might be attributable to an increased plasma-to-dialysate concentration gradient and/or to an increased effective peritoneal surface area. One of the factors affecting the latter is the peritoneal surface area in contact with dialysate (PSA-CD). The aim of this study was to estimate the change in PSA-CD after a 50% increase in the instilled dialysate volume for patients undergoing peritoneal dialysis. PSA-CD was estimated by using a method applying stereologic techniques to computed tomographic (CT) scans of the peritoneal space. The peritoneal cavity of 10 peritoneal dialysis patients was filled with a solution containing dialysate, half-isotonic saline solution, and contrast medium. Peritoneal function tests and CT scanning of the abdomen were performed twice for each patient (with an interval of 1 wk), after instillation of a 2- or 3-L solution. Scanning of thin helical CT sections was performed, and 36 random sections of the abdomen were obtained after reconstruction. A grid was superimposed on the sections. The surface area was estimated by using stereologic methods. After instillation of the 2-L solution, the volume of the peritoneal solution at the time of CT scanning was 2.32 +/- 0.05 L. The PSA-CD was 0.57 +/- 0.03 m(2), ranging from 0.41 to 0.76 m(2). The use of the 3-L solution increased the peritoneal volume by 46 +/- 2%. PSA-CD increased by 18 +/- 2.3% to 0.67 +/- 0.04 m(2) (range, 0.49 to 0.84 m(2); P < 0.01). Creatinine mass transfer increased from 112 +/- 10 mg to 142 +/- 11 mg (P < 0.0001). The slope of the change of the plasma-to-dialysate creatinine concentration gradient with time decreased from -2.26 +/- 0.23 x 10(-2) to -1.97 +/- 0.16 x 10(-2) (P = 0.01). K(BD-0) (permeability-surface area product or mass area transfer coefficient at time 0 of the dwell) increased from 10.6 +/- 0.7 to 13.6 +/- 1.2 ml/min (P < 0.02). These data demonstrate that increasing the instilled dialysate volume by 50% for peritoneal dialysis patients results in significant increases in the PSA-CD and K(BD).
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Affiliation(s)
- Avry Chagnac
- Department of Nephrology, Rabin Medical Center-Golda Campus, Tel Aviv University Medical School, Petah Tikva, Israel.
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