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Andrzej Breborowicz

Publications and source records attributed to Andrzej Breborowicz.

30 records · Page 2Linked to original sources
PubMed2003

Glucose degradation products in peritoneal dialysis fluids: do they harm?

BACKGROUND: Severe limitations in biocompatibility of conventional peritoneal dialysis fluids (PDF) can be partially attributed to the presence of glucose degradation products (GDP), which are generated during autoclaving of PDF. Formation of GDP can be significantly reduced by the use of multi-chamber bag systems. Recent clinical studies have revealed increased dialysate levels of pro-collagen I C-terminal peptide (PICP) in patients dialyzed with these solutions. Here, we briefly review the current knowledge on various aspects of GDP toxicity toward peritoneal cells and analyze the impact of GDP on PICP release by human peritoneal mesothelial cells (HPMC) in vitro. METHODS: HPMC were exposed to a mixture of known GDP added to culture medium at clinically relevant doses. After 12 days, the amount of PICP released was measured using an immunoassay. Furthermore, the protein synthesis was assessed by 3H-proline incorporation in HPMC exposed to peritoneal effluent obtained from patients after three months of CAPD with either conventional PDF or low-GDP solution. RESULTS: Exposure to GDP resulted in a significant decrease in PICP release by HPMC. In addition, the synthesis of new proteins secreted by HPMC was preserved significantly better in HPMC treated with effluent obtained when patients were dialyzed with low-GDP solutions rather than conventional PDF. CONCLUSIONS: Exposure to GDP may impair protein synthesis and secretion by HPMC. Therefore, increased dialysate PICP levels in response to GDP-free PDF may be viewed as evidence of improved mesothelial cell function.

Dialysis Solutions↗
PubMed2003

Glucose and mannitol have different effects on peritoneal morphology in chronically dialyzed rats.

In previous studies, we showed that glucose reduces the morphologic changes in rat peritoneum caused by chronic intraperitoneal administration of 0.9% NaCl solution. In the present study, we set out to determine if the observed results were attributable to hyperosmolarity or to the metabolic effect of the glucose. Intraperitoneal catheters were implanted in 19 rats. The animals were then intraperitoneally exposed twice daily for 30 days to 20 mL 0.9% saline supplemented with either 250 mmol/L glucose (GLU, n = 9) or 250 mmol/L mannitol (MAN, n = 10). Control rats did not undergo catheter implantation or the dialysis procedure (CON, n = 6). At the end of the study, a 1-hour peritoneal equilibration test (PET) using Dianeal 3.86% (Baxter Healthcare SA, Castlebar, Ireland) was performed in every dialyzed rat to analyze peritoneal transport. Afterward, the rats were humanely killed by bleeding, and a semi-quantitative scale was used to evaluate adhesions in the peritoneal cavity. Imprints of the visceral mesothelium and samples of the visceral peritoneum (liver) were then taken and analyzed by light microscopy. The PET results for glucose, urea, creatinine, and total protein were comparable in both experimental groups. We found that intraperitoneal adhesions were more severe in the MAN group (6 rats with adhesions graded > 3) than in the GLU group (only 1 such rat). No difference in peritoneal thickness was observed between the experimental groups (MAN: 54.9 +/- 17.8 microns; GLU: 51.2 +/- 14.5 microns); however, in both experimental groups, the thickness was greater than in the CON group (3.9 +/- 0.6 microns). The density of the peritoneal blood vessels tended to be greater in the MAN group than in the GLU group (0.158 +/- 0.072 vessels/1000 microns 2 vs. 0.085 +/- 0.067 vessels/1000 microns 2, p = 0.0541). No visible blood vessels were evident in the CON group. The density of mesothelial cells was higher in the MAN group than in the GLU group (2456 +/- 333 cells/mm 2 vs. 2090 +/- 322 cells/mm 2, p < 0.05), and, in both experimental groups, the cell density was higher than in the CON group (817 +/- 100 cells/mm 2, p < 0.01). The nucleus: cytoplasm area ratio in mesothelial cells was comparable in the MAN and GLU groups (0.206 +/- 0.039 and 0.176 +/- 0.045), but that ratio was higher in both experimental groups than in the CON group (0.086 +/- 0.010, p < 0.01). We conclude that glucose-induced changes in the peritoneum of rats exposed to chronic peritoneal dialysis depend on both osmotic and metabolic effects.

Animals↗
PubMed2003

Morphologic changes in the liver of dialyzed rats--preliminary observations.

Peritoneal dialysis affects both the quantity and quality of connective tissue in the visceral peritoneum. In the present study, we report the alterations observed in the morphology of the superficial liver lobuli of dialyzed rats. The studies were performed in male Wistar rats weighing 250-350 g. Rats were exposed intraperitoneally to 0.9% NaCl, phosphate-buffered saline (PBS), or commercial dialysis solutions containing 3.86% glucose (Dianeal 3.86%: Baxter Healthcare SA, Castlebar, Ireland; CAPD3 and CAPD3-Balance: Fresenius Medical Care, Bad Homburg, Germany) twice daily for 4-6 weeks. At the end of the study, samples of the liver were taken and stained for light microscopy (hematoxylin and eosin, van Gieson). The results obtained in dialyzed rats were compared with those from the control, non dialyzed animals. In control animals, the surface of the hepatic parenchyma was smooth. In all dialyzed rats, irrespective of the solution used, folding of the surface of the liver parenchyma was found owing to penetration of connective tissue elements between the hepatocytes. In effect, folds of hepatocytes within the liver capsule became detached and isolated from the remaining cells of the lobules. The distinctive feature of that pathologic change was that its severity increased with the thickness of the peritoneum. The change was seen in rats exposed to any of the experimental solutions, and therefore appeared to be attributable to a non-specific reaction caused by exposure of the peritoneum to dialysis fluid and not to specific components of the fluid. The observed alterations in morphology seem to suggest disturbed function within the affected lobules. Further studies are necessary to confirm this hypothesis.

Animals↗
PubMed2002

Glucose suppresses peritoneal inflammatory reactions and mesothelial hyperplasia caused by intraperitoneal saline infusion.

In the past, we had observed that infusion of normal saline into the peritoneal cavity stimulates an inflammatory response. In the present study, we examined what effect the addition of glucose to normal saline would have on the peritoneal inflammatory response and change in peritoneal morphology. After catheter implantation, rats were infused intraperitoneally (i.p.) for 3 days with Dianeal 1.36% (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.). Dialysate samples were collected on day 3 after a 4-hour dwell. Next, rats were exposed to either NaCl (n = 7) or NaCl with glucose 250 mmol/L (Glu, n = 7) twice daily for 4 weeks. After 2 weeks and 4 weeks of the study, dialysate samples were collected after a 4-hour dwell to analyze the activity of inflammatory reaction. At the end of the experiment, imprints of peritoneal mesothelium were taken. Control animals (C, n = 6) did not undergo catheter implantation or the dialysis procedure. The inflammatory reaction--cell count, cell differentiation, nitric oxide production, protein loss, and monocyte chemoattractant protein-1 (MCP-1) concentration in dialysate expressed as a percentage of the initial value--did not change during the study in rats exposed to NaCl. On the other hand, in Glu-treated animals, the protein concentration was decreased after 4 weeks of the study (74% +/- 23%, p < 0.05), as was MCP-1 (24% +/- 12%, p < 0.05). The nitrites concentration was decreased after 2 weeks (72% +/- 19%; p < 0.05). Intraperitoneal adhesions were found in 6 rats of the NaCl group (86%) and in only 4 rats (57%) of Glu group. In the NaCl rats, a higher density of mesothelial cells was observed (2792 +/- 510 cells/mm2) as compared with Glu rats (2028 +/- 561 cells/mm2; p < 0.05) and with control rats (1629 +/- 422 cells/mm2, p < 0.05). The NaCl group also showed a higher nucleus: cytoplasm surface ratio (0.25 +/- 0.03) as compared with the Glu group (0.18 +/- 0.02, p < 0.01) and with the control group (0.14 +/- 0.01, p < 0.01). Addition of glucose to normal saline suppresses the peritoneal inflammatory response and mesothelial hyperplasia occurring with intraperitoneal infusion of NaCl solution alone.

Animals↗
PubMed2001

Prolonged exposure to glucose degradation products impairs viability and function of human peritoneal mesothelial cells.

Bioincompatibility of peritoneal dialysis fluids (PDF) has been linked to the presence of glucose degradation products (GDP). Previous experiments have shown that short-term exposure to several GDP at concentrations found in commercially available PDF had no significant effect on human peritoneal mesothelial cells (HPMC). During continuous ambulatory peritoneal dialysis, however, cells are continually exposed to GDP for extended periods of time. Thus, the impact of GDP on HPMC during long-term exposure was assessed. HPMC were cultured for up to 36 d in the presence of 6 identified GDP (acetaldehyde, formaldehyde, furaldehyde, glyoxal, methylglyoxal, and 5-HMF) at doses that reflect their concentrations in conventional PDF. At regular time intervals, the ability of HPMC to secrete cytokines (interleukin-6 [IL-6]) and extracellular matrix molecules (fibronectin) was evaluated. In addition, cell viability, morphology, and proliferative potential were assessed. Exposure to GDP resulted in a significant reduction in mesothelial IL-6 and fibronectin release. Approximately 80% of this decrease occurred during the first 12 d of the exposure and was paralleled by a gradual loss of cell viability and development of morphologic alterations. After 36 d of exposure, the number of cells in GDP-treated cultures was reduced by nearly 60%. However, GDP-treated cells were able to resume normal proliferation when transferred to a normal GDP-free medium. HPMC viability and function may be impaired during long-term exposure to clinically relevant concentrations of GDP, which suggests a potential role of GDP in the pathogenesis of peritoneal membrane dysfunction during chronic peritoneal dialysis.

Aldehydes↗
PubMed2000

Effect of glucose degradation products on human peritoneal mesothelial cell function.

Bioincompatibility of conventional glucose-based peritoneal dialysis fluids (PDF) has been partially attributed to the presence of glucose degradation products (GDP) generated during heat sterilization of PDF. Most previous studies on GDP toxicity were performed on animal and/or transformed cell lines, and the impact of GDP on peritoneal cells remains obscure. The short-term effects of six identified GDP on human peritoneal mesothelial cell (HPMC) functions were examined in comparison to murine L929 fibroblasts. Exposure of HPMC to acetaldehyde, formaldehyde, glyoxal, methylglyoxal, furaldehyde, but not to 5-hydroxymethyl-furfural, resulted in dose-dependent inhibition of cell growth, viability, and interleukin-1beta (IL-1beta)-stimulated IL-6 release; for several GDP, this suppression was significantly greater compared with L929 cells. Although the addition of GDP to culture medium at concentrations found in PDF had no major impact on HPMC function, the exposure of HPMC to filter-sterilized PDF led to a significantly smaller suppression of HPMC proliferation compared to that induced by heat-sterilized PDF. The growth inhibition mediated by filter-sterilized PDF could be increased after the addition of clinically relevant doses of GDP. These effects were equally evident in L929 cells. In conclusion, GDP reveal a significant cytotoxic potential toward HPMC that may be underestimated in test systems using L929 cells. GDP-related toxicity appears to be particularly evident in experimental systems using proliferating cells and the milieu of dialysis fluids. Thus, these observations may bear biologic relevance in vivo where HPMC are repeatedly exposed to GDP-containing PDF for extended periods of time.

Cell Division↗
PubMedDate not supplied

L-2-oxothiazolidine-4-carboxylate: an agent that modulates lipopolysaccharide-induced peritonitis in rats.

OBJECTIVE: L-2-Oxothiazolidine-4-carboxylate (OTZ), a cysteine precursor, is a substrate for intracellular glutathione synthesis. As shown previously, OTZ prevents free-radical induced cellular damage during in vitro simulation of peritoneal dialysis. In the present study, we examined the effect of adding OTZ to peritoneal dialysis solution on peritoneal function and structure during lipopolysaccharide (LPS)-induced peritonitis in rats. In addition, we studied the effects of pretreatment with OTZ (given orally) on the effects of LPS-induced peritonitis in rats. METHODS: Peritonitis was induced in rats by adding LPS (5 microg/mL) to the dialysis fluid. For acute experiments, rats were exposed to a single infusion of dialysis solution containing LPS or to LPS plus 5 mmol/L OTZ; peritoneal cell counts and permeability were determined after 4 hours. Alternatively, rats were pretreated with OTZ added to the drinking water (0.1%) for 10 days prior to infusion of LPS. For chronic experiments, peritoneal dialysis was performed over a 3-week period in rats with implanted peritoneal catheters. On days 8, 9, and 10 of the experiment, the rats were infused intraperitoneally with solution containing LPS (5 micro/mL), or LPS plus 5 mmol/L OTZ, to induce acute peritonitis. At the end of dialysis (10 days after the episodes of peritonitis), peritoneal function was assessed using a peritoneal equilibration test (PET), and peritoneal biopsies were taken to assess effects on peritoneal morphology. RESULTS: In the acute experiments, exposure to LPS led to increased peritoneal cell counts (+61% vs control, p < 0.05) and enhanced permeability of the peritoneum, leading to a loss in ultrafiltration (-63%, p < 0.0005). The glutathione concentration in peritoneal leukocytes also decreased during acute peritonitis (-31%, p < 0.05). During LPS-induced peritonitis, OTZ prevented the increase in dialysate cell count and the decrease in cellular glutathione content. Simultaneous administration of OTZ did not prevent the increased peritoneal permeability induced by LPS. However, in rats pretreated with OTZ, LPS-induced permeability to protein was significantly lower than in the nontreated animals (0.049 +/- 0.011 vs 0.087 +/- 0.034, p < 0.05). In the chronic experiments, LPS-induced peritonitis did not lead to any functional differences in peritoneal transport at the end of 3 weeks of dialysis. However, LPS-induced peritonitis led to increased thickness of the peritoneum and neovascularization within peritoneal interstitium compared to peritonitis-free animals. In contrast to the LPS-treated animals, the peritoneum of the rats exposed to LPS in the presence of OTZ was of a thickness similar to that in the control rats. CONCLUSION: Supplementation of dialysis fluid with OTZ prevented changes in cellular glutathione levels and dialysate cell counts during acute peritonitis in rats. During chronic dialysis in rats exposed to intermittent peritonitis episodes, OTZ prevented increased thickening and neovascularization of the peritoneum. Our results suggest this may help to protect the peritoneal membrane during episodes of peritonitis.

Administration, Oral↗
PubMedDate not supplied

Effects of intraperitoneal hyaluronan on peritoneal fluid and solute transport in peritoneal dialysis patients.

BACKGROUND: Hyaluronan (HA) is a glycosaminoglycan found in connective tissues and tissue spaces, including the peritoneal cavity. In vivo studies in a rat model of peritoneal dialysis (PD) have shown that addition of HA to PD solution during an intraperitoneal dwell can alter peritoneal fluid transport and protect the peritoneal membrane from the effects of inflammation and repeated infusions of dialysis solution. The current study sought to evaluate the safety of intraperitoneal HA and its effect on peritoneal fluid and solute transport when administered during a dialysis dwell in humans. METHODS: 13 PD patients were enrolled in a prospective, randomized crossover study involving three dialysis treatments using the following PD solutions: (1) a commercially available PD solution (Dianeal PD-4, 1.36% glucose; Baxter Healthcare Corporation, Alliston, Ontario, Canada); (2) Dianeal PD-4 containing 0.1 g/L HA, and (3) Dianeal PD-4 containing 0.5 g/L HA. Each 6-hour dialysis exchange was separated from the other exchanges by a 2-week washout period. Radioiodinated human serum albumin (RISA) was administered with the dialysis solution to evaluate intraperitoneal volume, net ultrafiltration (UF), and fluid reabsorption. Peritoneal clearances, dialysate/plasma ratios (D/P), and mass transfer area coefficients (MTACs) were determined for sodium, urea, creatinine, albumin, and glucose. Safety was evaluated by monitoring adverse events and changes in serum chemistries. Ten patients completed all three dialysis exchanges and two additional patients completed at least one treatment exchange. RESULTS: There were no reported adverse events related to HA administration and no significant changes in serum chemistries. There were no significant differences in net UF or peritoneal volume profiles among the three treatments. Mean net UF calculated using residual volumes, estimated by RISA dilution, tended to be slightly higher during treatment with solution containing 0.1 g/L HA and 0.5 g/L HA [74 +/- 86 (SE) and 41 +/- 99 mL, respectively] compared to control treatment (-58 +/- 129 mL). Although not statistically significant, there was a trend toward decreased fluid reabsorption during treatment with HA. Solute clearances, D/P ratios, and MTACs were similar for the three treatments. Serum levels of HA were also unaffected by the two treatment solutions. CONCLUSIONS: These data support the acute safety of HA when administered intraperitoneally with the dialysis solution to PD patients. Due to the small sample size and variability in net UF and fluid reabsorption, statistically significant differences were not demonstrated for these parameters. However, a trend toward decreased fluid reabsorption was observed, suggesting that HA may act by a mechanism similar to that observed in animal studies. Further studies are necessary to evaluate whether the beneficial effects of HA observed in animal studies can be shown in humans.

Adjuvants, Immunologic↗
PubMedDate not supplied

Mesothelial toxicity of peritoneal dialysis fluids is related primarily to glucose degradation products, not to glucose per se.

OBJECTIVES: High concentrations of glucose and/or formation of glucose degradation products (GDPs) during heat sterilization of peritoneal dialysis fluids (PDFs) are believed to be key factors in the limited biocompatibility of PDFs. We have previously shown that several identified GDPs can specifically impair human peritoneal mesothelial cell (HPMC) function. In the present study we aimed at differentiating the respective roles of glucose and GDPs in the toxicity of PDF to mesothelial cells. METHODS: HPMCs were acutely pre-exposed to or incubated chronically in the presence of pH-neutral PDF sterilized by either heat (H-PDF) or filtration (F-PDF). In addition, HPMCs were treated with commercially available H-PDF manufactured either conventionally, that is, in single-chamber containers, or using novel dual-chamber bags that help to substantially decrease GDP formation. Functional assessment of HPMCs included viability, release of interleukin (IL)-6, and proliferation. RESULTS: Viability and release of IL-6 from HPMCs pretreated with H-PDF (pH 7.3) for 1 to 4 hours were significantly reduced compared to cells exposed to corresponding F-PDF. Incubation in medium mixed (1:1) with H-PDF considerably impaired growth of HPMCs, and over a period of 10 days gradually decreased both the viability of HPMCs and their ability to generate IL-6. These effects were either absent from or significantly less in HPMCs exposed to F-PDF. Similar differences were observed when commercial GDP-containing H-PDFs were compared with newly designed H-PDFs free of GDPs. CONCLUSIONS: Impaired viability and function of HPMCs exposed to glucose-containing pH-neutral PDF is related predominantly to the presence of GDP and, to a significantly lesser extent, to the presence of glucose per se. Prevention of GDP formation during autoclaving markedly improves the biocompatibility of H-PDF with HPMCs.

Cell Division↗
PubMedDate not supplied

Evidence for less irritation to the peritoneal membrane in rats dialyzed with solutions low in glucose degradation products.

BACKGROUND: Acidic pH and the presence of glucose degradation products (GDP) are believed to compromise the biocompatibility of peritoneal dialysis fluids (PDF). The present study examines the effects of long-term exposure to GDP and low pH by comparing conventional PDF and a new, neutral pH, low GDP solution. METHODS: All experiments were performed using a chronic infusion model of dialysis in nonuremic rats. The animals were treated for 6 weeks with 2 daily injections of 4.25% glucose-containing PDF. The following PDF were tested: CAPD3 (single-chamber bag, low pH, high GDP), CAPD3 pH 7.4 (single-chamber bag, neutral pH, high GDP), CAPD3-Balance (double-chamber bag, neutral pH, low GDP). All test solutions were obtained from Fresenius Medical Care, Bad Homburg, Germany. RESULTS: After 6 weeks of exposure, peritoneal permeability to water, urea, creatinine, glucose, and sodium, assessed by peritoneal equilibration test, was similar in all groups. However, compared to other PDF, dialysis with CAPD3-Balance was associated with reduced concentrations of protein and hyaluronan in the dialysate, decreased peritoneal eosinophilia, and reduced dialysate levels of chemokines CCL2/MCP-1 and CCL5/RANTES. Morphologic changes in the peritoneal membrane of CAPD3-Balance-treated animals were much less pronounced and included reduced vascular density, preservation of the mesothelial monolayer and intercellular junction, and no reduplication of the submesothelial basement membrane. CONCLUSIONS: A new generation of PDF with physiologic pH and low GDP level produce less irritation to the peritoneal membrane and better preserve its structural integrity. This effect seems to be related predominantly to minimized GDP concentrations.

Animals↗
PubMedDate not supplied

The role of the glyoxalase pathway in reducing mesothelial toxicity of glucose degradation products.

BACKGROUND: The glucose degradation products (GDP) presentin conventional peritoneal dialysis fluids (PDF) may exert adverse effects toward human peritoneal mesothelial cells (HPMC). Some GDP can be detoxified by the glyoxalase/ glutathione pathway. It has been shown that the addition of glyoxalase I (GLO-I) and reduced glutathione (GSH) to PDF effectively eliminates GDP. We have therefore examined the GLO-I/GSH system in HPMC and assessed the impact of GLO-I/ GSH-treated PDF on the viability and function of HPMC. METHODS: Heat-sterilized PDF (H-PDF) was incubated in the presence or absence of GLO-I and GSH for 1 hour at 37 degrees C, and then mixed with an equal volume of serum-free M199 medium and applied to HPMCin culture. After 24 hours, HPMC were assessed for viability, the release of interleukin-6, GLO-I activity, and cellular glutathione. The effects were compared to those exerted by filter-sterilized PDF (F-PDF), which was devoid of GDP. RESULTS: Exposure of HPMC to H-PDF resulted in reduced GLO-I activity, GSH depletion, and a decrease in cell viability. Pretreatment of H-PDF with either a combination of GLO-I and GSH or GSH alone markedly reduced inhibitory effects of H-PDF toward HPMC, as measured by cell viability and inter-Leukin-6 generation. Exposure of HPMC to the GSH precursor L-2-oxothiazolidine-carboxylic acid increased cellular GSH and prevented the loss of GLO-I activity in response to H-PDF. CONCLUSIONS: Exposure to conventional GDP-rich PDF impairs the activity of the glyoxalase/glutathione system in HPMC. Pretreatment of PDF with GSH or replenishment of cellular GSH protects HPMC against GDP-mediated toxicity.

Cells, Cultured↗