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PubMed2002

Blood glucose overestimation in diabetic patients on continuous ambulatory peritoneal dialysis for end-stage renal disease.

AIMS: Diabetic patients on continuous ambulatory peritoneal dialysis (CAPD) for renal failure depend on glucose analysers for regular monitoring of glycaemic control. We aim to inform health professionals of the potentially dangerous overestimation of blood glucose values by some analysers in patients using Icodextrin for dialysis. METHODS: Twenty-five patients on continuous ambulatory peritoneal dialysis (10 patients on an 8-12-h nocturnal exchange of Icodextrin) had random glucose analysis performed on venous blood using standardized reference laboratory (lab) technique (glucose oxidase GOD-PAP), and simultaneously on capillary blood using the Precision Q.I.D System (glucose oxidase method) and the Advantage meter (glucose dehydrogenase method). RESULTS: The Precision Q.I.D System agreed with the lab results in both the Icodextrin group and the non-Icodextrin group (80-90% of values fell within 20% of the corresponding lab result). In contrast, the Advantage meter agreed with the lab results only in the non-Icodextrin group (95% of values within 20% of the corresponding lab value), and not in the Icodextrin group, where only 5% of the analyser values fell within 20% of the corresponding lab value. CONCLUSIONS: The Precision Q.I.D System, which utilizes glucose oxidase reaction, is safe for use in diabetic patients treated with Icodextrin. All analysers must be cross-checked with the laboratory reference method before use in these patients.

Adolescent↗

PubMed2000

Effect of peritonitis on peritoneal transport characteristics: glucose solution versus polyglucose solution.

BACKGROUND: Peritonitis is a common clinical problem and contributes to the high rate of technique failure in continuous ambulatory peritoneal dialysis treatment. The present study investigated the effect of peritonitis on peritoneal fluid and solute transport characteristics using glucose and polyglucose (icodextrin) solutions. METHODS: A four-hour dwell was performed in 32 Sprague-Dawley rats (8 rats in each group), with 131I albumin as an intraperitoneal volume marker. Peritonitis was induced by an intraperitoneal injection of 2 mL lipopolysaccharide (100 microg/mL phosphate-buffered saline) four hours before the dwell. Each rat was intraperitoneally infused with 25 mL of 3.86% glucose [glucose solution control group (Gcon) and glucose solution peritonitis group (Gpts)] or 7.5% icodextrin solution [icodextrin solution control group (Pgcon) and icodextrin peritonitis group (PGpts)]. RESULTS: Net ultrafiltration was significantly lower (by 44%) in the Gpts as compared with the Gcon group, but was significantly higher (by 138%) in the PGpts as compared with the PGcon group. The peritoneal fluid absorption rate, including the direct lymphatic absorption rate, was significantly increased (by 78%) in the Gpts group as compared with the Gcon group. However, the total fluid absorption did not differ between the PGpts and the PGcon groups. The dialysate osmolality decreased much faster in the Gpts group as compared with the Gcon group, resulting in significantly lower (by 9%) transcapillary ultrafiltration in the Gpts group. In contrast, the dialysate osmolality increased faster in the PGpts group as compared with the PGcon group, resulting in higher (by 40%) transcapillary ultrafiltration in the PGpts group. The in vitro increase in dialysate osmolality was also higher in the PGpts group as compared with the PGcon group. The solute diffusive transport rates were, in general, increased in the two peritonitis groups as compared with their respective control groups. CONCLUSIONS: Our results suggest the following: (1) Peritonitis results in decreased net ultrafiltration using glucose solution caused by (a) decreased transcapillary ultrafiltration and (b) increased peritoneal fluid absorption. (2) Ultrafiltration induced by the icodextrin solution appears to be related to the increase in dialysate osmolality (mainly because of the degradation of icodextrin). (3) Peritonitis results in increased degradation of icodextrin and a faster increase in dialysate osmolality and therefore better ultrafiltration, whereas the fluid absorption rate does not change. (4) Peritonitis results in increased peritoneal diffusive permeability.

Animals↗

PubMed2004

Peritoneal transport characteristics with glucose polymer-based dialysis fluid in children.

Scarce data are available on the use of glucose polymer-based dialysate in children. The effects of glucose polymer-based dialysate on peritoneal fluid kinetics and solute transport were studied in pediatric patients who were on chronic peritoneal dialysis, and a comparison was made with previously published results in adult patients. In nine children, two peritoneal equilibration tests were performed using 3.86% glucose and 7.5% icodextrin as a test solution. Dextran 70 was added as a volume marker to calculate fluid kinetics. Serum and dialysate samples were taken for determination of urea, creatinine, and sodium. After calculation of the initial transcapillary ultrafiltration (TCUF) rate, it was possible to calculate the contribution of aquaporin-mediated (AQP-mediated) water transport to ultrafiltration for icodextrin and 3.86% glucose and the part of L(p)S (the product of the peritoneal surface area and the hydraulic permeability) caused by AQP. In children, the transport parameters were similar for the two solutions, except for TCUF, which was lower for icodextrin (0.9 ml/min per 1.73 m(2)) as compared with 3.86% glucose (4 ml/min per 1.73 m(2)). Transport parameters were similar in children and adults for glucose, but with icodextrin, TCUF and marker clearance were significantly lower in children. AQP-mediated water flow was 83 versus 50% with glucose (child versus adult; P < 0.01) and 18 versus 7% with icodextrin (P < 0.01). Data indicate that transport parameters in children using icodextrin are similar to glucose except for TCUF. Differences are explained by the absence of crystalloid osmosis and that TCUF was determined after a 4-h dwell. Comparison of transport parameters and peritoneal membrane characteristics between children and adults reveal that there seem to be differences in the amount and functionality of AQP. However, there are no differences in clinical efficacy of this transport pathway because the absolute flow through the AQP is identical in both groups using 3.86% glucose.

Adult↗

PubMed1999

Decreased in vitro formation of AGEs with extraneal solution compared to dextrose-containing peritoneal dialysis solutions.

Extraneal peritoneal dialysis (PD) solution (Baxter Healthcare, Deerfield, Illinois, U.S.A.) contains glucose polymer (icodextrin) as an osmotic agent in place of dextrose. We investigated the ability of Extraneal to form advanced glycation end products (AGEs) in vitro compared to standard PD solutions containing dextrose. Extraneal, Dianeal PD-2 [1.5%, 2.5%, or 4.25% dextrose (Baxter Healthcare)], or phosphate buffered saline (PBS) were incubated for 45 days with human serum albumin (HSA) or type IV collagen. AGE formation was measured by spectrofluorometry using excitation at 350 nm and emission at 430 nm. Solutions were also incubated with collagen affixed to plastic, simulating matrix collagen in the peritoneal membrane. In addition, AGE formation was assessed using icodextrin metabolites (maltose, maltotriose, and maltotetraose) at concentrations normally found in the plasma of patients treated using icodextrin. For PD solutions incubated with albumin, the relative order of AGE formation was: 4.25% dextrose > 2.5% dextrose > 1.5% dextrose > Extraneal. For incubations with collagen (in solution or affixed to plastic), AGE formation was greatest for 4.25% dextrose, intermediate for Extraneal and 2.5% dextrose, and lowest for 1.5% dextrose. Incubation of icodextrin metabolites with albumin for 45 days did not result in appreciable AGE formation. These results confirm that solutions containing icodextrin result in less in vitro AGE formation than do high dextrose solutions. The results also suggest that Extraneal may lead to improved solution biocompatibility in vivo.

Glucans↗

PubMedDate not supplied

Advanced glycosylation end-products in diabetic rats on peritoneal dialysis using various solutions.

OBJECTIVE: To evaluate and compare the effects of glucose-based solutions to those of icodextrin with respect to peritoneal transport characteristics and advanced glycosylation end-product (AGE) formation in the peritoneal membrane in a diabetic rat model of peritoneal dialysis (PD). DESIGN: Thirty-three male Sprague-Dawley rats weighing between 275-300 g were divided into five groups: group C (n = 6), control rats implanted with a catheter but not dialyzed; group D (n = 5), diabetic rats implanted with a catheter but not dialyzed; group G (n = 7), diabetic rats implanted with a catheter and dialyzed with standard 2.5% glucose solution for daytime exchanges and 4.25% glucose solution for overnight exchanges; group H (n = 8), diabetic rats implanted with a catheter and dialyzed with standard 2.5% glucose solution for daytime exchanges and 7.5% icodextrin solution for overnight exchanges; group I (n = 7), diabetic rats implanted with a catheter and dialyzed with 7.5% icodextrin solution for all exchanges. Dialysis exchanges (25 mL per exchange) were performed three times daily for a period of 12 weeks. Tissue sections were stained using a monoclonal anti-AGE antibody. One-hour peritoneal equilibration tests (PET) were performed every 4 weeks for comparison of transport characteristics. RESULTS: The level of immunostaining was lowest in group C and highest in group G. Significant differences in immunostaining were seen between group C and group G (p < 0.001), group C and group H (p = 0.001), and group C and group I (p < 0.05). Significant differences were also found between group G and group D (p < 0.05), and between group G and group I (p < 0.05). Over time, the ratio of glucose concentration after 1 hour to glucose concentration at instillation (D/D0) decreased and the dialysate-to-plasma ratio (D/P) of urea increased. Significant differences in D/D0 glucose and D/P urea were found between group C and group H (D/D0: 0.40 +/- 0.01 vs 0.35 +/- 0.01, p < 0.05; D/P urea: 0.87 +/- 0.03 vs 0.97 +/- 0.02, p < 0.05). CONCLUSIONS: These results suggest that AGE formation is lower with the use of peritoneal dialysis solution containing icodextrin than with glucose-based solution. We conclude that use of icodextrin may help to slow the deterioration of the peritoneal membrane, prolonging its use for dialysis.

Animals↗

PubMed2005

Osmotic agents hamper mesothelial repopulation as seen in the doughnut in vivo model.

BACKGROUND: The problem of mesothelial cell injury derived from the use of peritoneal dialysis solutions has been explored deeply. Conversely, the eventual detrimental effects upon mesothelial cell regeneration have awaked less investigative efforts than those focused on injury. OBJECTIVE: To evaluate in the in vivo and in situ rat "doughnut" model of mesothelial repopulation, the eventual effect of peritoneal lavage with Hank's Balanced Salt Solution (HBSS) as well as that of 4.25% glucose and 7.5% icodextrin dialysis solutions. EXPERIMENTAL ANIMALS: 100 Sprague-Dawley albino rats were included in the study. Animals were divided into five groups of 20 rats each: group 1: control at zero time; group 2: sham-injected rats; group 3: rats exposed to HBSS; group 4: rats treated with 4.25% glucose peritoneal dialysis solution; group 5: rats injected with 7.5% icodextrin. METHODS: Selective exfoliation of a ring of mesothelium (width 0.8 mm, diameter 4 mm) covering the anterior surface of the liver was performed in 80 animals. The control zero-time group was used to evaluate the normal density distribution of the mesothelial cells forming the monolayer. The other groups were treated by means of daily sham injections or intraperitoneal infusion of each experimental solution for a period of 30 consecutive days. After a recovery period of 15 days, imprints and biopsies from the monolayer covering the exfoliated area were taken and processed for light microscopy. RESULTS: Macroscopic observation of the abdominal cavity at the end of the 15-day recovery period showed that the prevalence of fibrotic adhesions between the peritoneal exfoliated area and the neighboring diaphragm was 10% forthe sham-injected group, 5% for the HBSS-exposed animals, 85% for the rats injected with 4.25% glucose, and 95% for the icodextrin-treated group. Prevalence of fibrous adhesions in sham-injected animals and rats exposed to HBSS were devoid of statistically significant differences. Conversely, comparison of these groups with results observed in animals treated with the osmotic agents was significant, at the p < 0.0039 level. Regarding density distribution of mesothelial cells observed in imprints, there were no significant differences between the control zero-time and the sham-injected group. This parameter was marginally lower (p < 0.05) in the HBSS-treated rats. Imprints were not taken from animals exposed to glucose or icodextrin because a dense layer of connective tissue replaced the exfoliated mesothelial area. CONCLUSIONS: Observations made in this study support the contention that both osmotic agents, 4.25% glucose and 7.5% icodextrin, substantially restrain the normal process of mesothelial cell repopulation and induce repair by means of connective tissue. The underlying mechanism is most likely sustained oxidative stress.

Animals↗

PubMed2005

[Influence of hyaluronan on peritoneal permeability for macromolecules in vitro].

Recent studies pointed out advantages of high-molecular hyaluronic acid (HA) application into dialysis fluids. This molecule is an essential component of peritoneal extracellular matrix. The compound shows antiadhesive properties and participates in restoring of peritoneal integrality and remodeling of peritoneum, which have been changed by prolonged peritoneal dialysis and returning incidents of peritonitis. Influence of HA on transperitoneal transport of large and small molecules is recognized in a little range. The aim of presented studies in vitro was qualification of hyaluronan influence on transport dynamics of the selected macromolecules (albumin 1 g/dL, icodextrin 7.5 g/dL and insulin 0.1 g/dL). Values of the transfer, directed from the interstitial to the mesothelial side of membrane (I-->M) and in the opposite direction (M-->I) were expressed as coefficient of diffusive permeability P [cm/s]. In the case of each macromolecule, two separate research series of the experiments were done. In the first one transperitoneal transport in the control conditions (120 min) was analyzed, and in the secondtransfer parameters before (15-60 min) and after hyaluronan (0.04 g/dL) application on the mesothelial side of peritoneal membrane (75-120 min) were examined. Stability of albumin and insulin transport (in the case of the both transfer directions) and icodextin passage (only M-->I direction) was observed in the presented studies when we compare the first and the second hours of the experiments. In the opposite direction (I-->M) it was showed an increase of its transport with time by about 50%. The mean values of P +/- SEM amounted to 0,271 +/- 0,056 [x10(-4); cm/s] and 0,315 +/- 0,057 [x10(-4); cm/s] for albumin and 0,145 +/- 0,033 [x10(-4); cm/s] and 0,146 +/- 0,022 [x10(-4); cm/s] for insulin, respectively in the case of I-->M and M-->I directions and 0,194 +/- 0,035 [x10(-4); cm/s] for icodextrin transfer directed from the mesothelial to the interstitial side of membrane. In the opposite direction (I-->M) values of P coefficient amounted to: 0,280 +/- 0,038 [x10(-4); cm/s] in the first experimental hour, and 0,394 +/- 0,046 [x10(-4); cm/s] in the second one. It was observed also asymmetry of glucose polymer passage with I-->M transfer domination. Hyaluronan eliminated this asymmetry. After use this compound the transport parameters of icodextrin were stable for the both I-->M and M-->I directions. Hyaluronan did not change values of diffusive permeability coefficients P in the case of bidirectional transfer of albumin and insulin. The obtained results show, that values of macromolecules transfer across peritoneum in vitro don't depend on their molecular weight and isoelectric points. Dynamics of albumin and insulin transperitoneal passage is stable. Icodextrin transport, directed from the interstitial to the mesothelial side of membrane, predominates transfer in the opposite direction. Hyaluronan modifies dynamics of transperitoneal icodextrin passage, but doesn't influence on permeability of the membrane in the case of albumin and insulin.

Albumins↗

PubMed2005

[Influence of new dialysis solutions on clinical results in patients treated with peritoneal dialysis].

Long-term peritoneal dialysis is associated with changes in the peritoneal membrane. Conventional dialysate solutions are bioincompatible because of their low pH, high glucose content, hyperosmolality and increased concentration of glucose degradation products. The development of double-compartment systems has made it possible to separate glucose from the buffer during heat sterilization, resulting in a higher or even physiologic pH of the solution with reduced concentration of glucose degradation products. These new solutions are less toxic for several cell groups and are better than conventional solutions in preserving membrane function, as demonstrated by experiments in rats. Glucose degradation products promote formation of advanced glycation end-products, and plasma levels of these are markedly reduced when double-compartment systems are used. Clinical studies with these more physiologic dialysis solutions have demonstrated better correction of acidosis, less inflow pain, significantly elevated CA-125 dialysate levels and lower concentrations of markers for inflammation and fibrosis in the effluent. In a retrospective study, a lower rate of mortality was observed in patients who were treated using a double-compartment system than in those treated with standard dialysis solution. Amino acids (in the low-molecular-weight range) and icodextrin (in the high-molecular-weight range) are newer osmotic agents that have been developed as alternatives to glucose. Several clinical studies have shown that amino-acid solution improves various nutritional parameters in patients with malnutrition and is more biocompatible than standard glucose solution. Icodextrin is an iso-osmolar dialysis solution. Ultrafiltration takes place via colloid osmotic pressure and is sufficient in all types of peritoneal transport. Clinical studies using icodextrin have shown better fluid control, especially in high transporters, reduced carbohydrate load and fewer patients with ultrafiltration failure compared with those treated with conventional dialysis solutions. However, allergic skin reactions have been observed in up to 10% of patients treated with icodextrin. Icodextrin may induce a fall of sodium plasma levels. Because of cross-reaction with elevated plasma levels of maltose, serum amylase is determined falsely low and glucose (using the glucose-dehydrogenase method) is measured falsely high, but high plasma levels of maltose do not affect measurement of lipase or measurement of glucose using the glucose-oxidase method. New dialysate solutions will have a positive influence on both survival and technical drop-out rates in patients receiving peritoneal dialysis treatment.

Clinical Trials as Topic↗

PubMed2003

Effect of intraperitoneal antiadhesive fluids in a rat peritonitis model.

HYPOTHESIS: Phospholipids and icodextrin reduce peritoneal adhesions resulting from general peritonitis without promoting abscess formation. DESIGN: Evaluation of adhesion reduction fluids in a randomized animal study using a standardized peritonitis model. SETTING: Experimental animal model in a university laboratory. INTERVENTIONS: In 60 rats, experimental peritonitis was induced using the cecal ligation and puncture model. On day 1, the abdominal cavity was rinsed with 10 mL of isotonic sodium chloride solution and the cecum was resected. Animals were randomly assigned to 3 groups: the RL group, which received Ringer lactate intraperitoneally; the PL group, which received phospholipids intraperitoneally; and the ID group, which received icodextrin intraperitoneally. In each group, 50% of the animals were humanely killed at day 11 and 50% at day 21. MAIN OUTCOME MEASURES: The areas of adhesions were measured and the abscess formation was scored according to location and size. Abscesses, abdominal fluid, and blood were sampled for microbiologic workup. RESULTS: The median area of adhesions was significantly lower in the PL groups (PL(11), 43.7 mm(2); PL(21), 20.4 mm( 2)) than in the RL groups (RL(11), 163.8 mm(2); RL( 21), 120.9 mm(2)) and ID groups (ID(11), 418.5 mm( 2); ID(21), 218.6 mm(2)). Abscess formation was increased by icodextrin but not influenced by phospholipids, whereas microbiologic investigations did not reveal any differences among these 3 groups. CONCLUSIONS: In this model of general peritonitis, phospholipids significantly reduced adhesion formation without promoting septic complications. Icodextrin enhanced adhesion and abscess formation in this peritonitis model. Phospholipids may be beneficial for adhesion control in general peritonitis.

Abdominal Abscess↗

PubMed2005

Sodium sieving in children.

Sodium sieving is a consequence of dissociation between the amount of water and sodium transported over the peritoneal membrane. This dissociation occurs in the presence of aquaporin-mediated water transport. Sieving of sodium can be used as a rough measure for aquaporin-mediated water transport. Icodextrin contains glucose polymers, inducing ultrafiltration by colloid osmosis. Therefore, aquaporins play a minor role in ultrafiltration, which is confirmed by the absence of sodium sieving. Icodextrin is very suitable for the daytime dwell in children on a nightly intermittent peritoneal dialysis regimen. Ultrafiltration obtained with icodextrin is similar to ultrafiltration obtained with 3.86% glucose after a 12-hour dwell. When using icodextrin in children, it is also confirmed by the absence of sodium sieving that the aquaporins play a minor role in ultrafiltration.

Aquaporins↗

PubMed2001

A preceding exchange with polyglucose versus glucose solution modifies peritoneal equilibration test results.

The peritoneal equilibration test (PET) is an important tool for evaluating peritoneal membrane characteristics. The polyglucose icodextrin induces ultrafiltration caused by colloid osmosis through the small pores of the peritoneal membrane and therefore is especially effective during long dwell times. The main indications for polyglucose solutions are daytime dwells in patients on automated peritoneal dialysis and nighttime exchanges in continuous ambulatory peritoneal dialysis (CAPD) patients. In CAPD patients, PET is started immediately after the icodextrin exchange. Therefore, we performed two PETs in each of 15 CAPD patients. PET post-1.36% glucose was performed immediately after a preceding exchange with 2 L of 1.36% glucose dialysate solution (dwell time, 10 hours). PET postpolyglucose was started immediately after a preceding exchange with 2 L of 7.5% icodextrin solution (dwell time, 10 hours). The dialysate to plasma (D/P) ratio of creatinine, phosphate, and sodium during PET postpolyglucose was significantly greater than during PET post-1.36% glucose at 1, 2, 3, and 4 hours of dwell time. The quotient of dialysate glucose at 1, 2, and 4 hours of dwell time to dialysate glucose at 0 dwell time was significantly lower in PET postpolyglucose compared with PET post-1.36% glucose. In the case of creatinine, phosphate, and glucose, PET postpolyglucose curves tended to be steeper than those of PET post-1.36% glucose during the first hour of dwell time, whereas both curves were parallel between 1 and 4 hours of dwell time. The course of D/P ratio curves of urea nitrogen, protein, and albumin was nearly identical between PET postpolyglucose and PET post-1.36% glucose. In a subgroup of 5 patients, D/P ratios of creatinine and phosphate were also greater in PET postpolyglucose compared with PET performed after a long dwell with 2.27% glucose solution. Before a scheduled PET, CAPD patients using icodextrin solution during the nighttime should perform their nighttime exchange with conventional glucose solution.

Adult↗

PubMed2003

The potential role of advanced glycation end product and iNOS in chronic renal failure-related testicular dysfunction. An experimental study.

OBJECTIVES: To investigate the impact of advanced glycation end products (AGEs) and inducible nitric oxide synthase (iNOS) in chronic renal failure (CRF)-associated testicular dysfunction in an experimental model. In additionally, we examined whether different peritoneal dialysis (PD) fluids could contribute to the elevation in AGE level and iNOS expression in the testes. METHODS: Adult male Wistar rats, 10 and 12 weeks of age and weighing 200-330 g, were divided into 5 groups. Group 1 served as the control group. In group 2, CRF was induced and a peritoneal catheter was implanted, but the dialysis procedure was not performed until the end of the study. In group 3, CRF was induced and PD was performed with dialysis fluids containing 1.36% glucose and icodextrin. In group 4, CRF rats received dialysis fluids containing 3.86% glucose and icodextrin. Finally, an indwelling catheter was implanted and the dialysis procedure was performed using dialysis fluids containing 3.86% glucose and icodextrin (group 5). Chronic PD began 4 weeks after insertion of the catheter. Each morning, this fluid was drained and 20 ml dialysis fluid, containing either 1.36 or 3.86% glucose, was given intraperitoneally for 4 h in unanesthetized animals. Each evening, 20 ml icodextrin was given for 10 h. The dialysis procedure was performed for 8 weeks. The AGE level was determined from the 5-hydroxymethyl-2-furaldehyde (5-HMF) content of penis samples and iNOS expression was assessed by immunohistochemistry. RESULTS: The elevation of 5-HMF was significant in the testes from groups 2, 3, 4, and 5 when compared with group 1. Furthermore, the differences between groups 2 and 4, 3 and 4, and 4 and 5 were also significant (p < 0.05). Immunohistochemical analysis revealed the presence of iNOS predominantly in the Leydig cells. While iNOS staining was significantly lower in group 1 than in other groups, there were also significant differences between groups 2 and 3, 2 and 4, 2 and 5, 3 and 5, and 4 and 5 (p < 0.05). Finally, a significant statistical correlation was found between the 5-HMF and iNOS levels (r = 0.698, p = 0.001). CONCLUSIONS: The present study identifies, for the first time, a potential role of AGE and iNOS in experimental CRF-associated testicular dysfunction. In addition, we found that PD fluids containing glucose contribute to this effect. These results may lead to a better understanding of the pathophysiological pathway in CRF-related testicular dysfunction.

Animals↗

PubMed2004

Influence of convection on the diffusive transport and sieving of water and small solutes across the peritoneal membrane.

The three-pore model of peritoneal membrane physiology predicts sieving of small solutes as a result of the presence of a water-exclusive pathway. The purpose of this study was to measure the diffusive and convective components of small solute transport, including water, under differing convection. Triplicate studies were performed in eight stable individuals using 2-L exchanges of bicarbonate buffered 1.36 or 3.86% glucose and icodextrin. Diffusion of water was estimated by establishing an artificial gradient of deuterated water (HDO) between blood/body water and the dialysate. (125)RISA (radio-iodinated serum albumin) was used as an intraperitoneal volume marker to determine the net ultrafiltration and reabsorption of fluid. The mass transfer area coefficient (MTAC) for HDO and solutes was estimated using the Garred and Waniewski equations. The MTAC of HDO calculated for 1.36% glucose and icodextrin were similar (36.8 versus 39.7 ml/min; P = 0.3), whereas for other solutes, values obtained using icodextrin were consistently higher (P < 0.05). A significant increase in the MTAC of HDO was demonstrated with an increase in the convective flow of water when using 3.86% glucose (mean value, 49.5 ml/min; P < 0.05). MTAC for urea was also increased with 3.86% glucose. The identical MTAC for water using 1.36% glucose and icodextrin indicates that diffusion is predominantly through small pores, whereas the difference in MTAC for the remaining solutes is a reflection of their sieving. The increase in the MTAC of water and urea associated with an increase in convection is most likely due to increased mixing within the interstitium.

Biological Transport↗

PubMedDate not supplied

Stability of cefazolin sodium in four heparinized and non-heparinized dialysate solutions at 38 degrees C.

BACKGROUND: Intraperitoneal administration of antibiotics is often required in the treatment of peritoneal dialysis-associated peritonitis. Extended use and heating may affect drug stability. The objective of our study was to determine the stability of cefazolin sodium (125 mg/L and 500 mg/L) in heparinized and non-heparinized dextrosecontaining peritoneal dialysis solution (Dianeal PD-2; Baxter Healthcare, Deerfield, Illinois, USA) containing 1.5%, 2.5%, or 4.25% dextrose, or 7.5% icodextrin, the new colloid formulation (Extraneal; Baxter), at 38 degrees C for 4 days. METHODS: Three poly-vinyl chloride containers of each dialysis fluid were stored at 38 degrees C for 4 days. Samples were taken after the bags were mixed and allowed to stand for 2 minutes. Two 500-microL samples were collected from each bag at hours 0, 12, 24, 36, 48, 60, 72, 84, and 96. Samples were then analyzed by high-performance liquid chromatography (HPLC) in our laboratory. In order to establish the stability-indicating nature of the method, drugs 1.0 mg/mL, vehicles, and their mixtures were subjected to a forced degradation. This is done by acid (2.0 mol/L HCl) and base (2.0 mol/L NaOH) hydrolysis, oxidation (H(2)O(2) 0.3%), and heat at 80 degrees C. Samples were analyzed every 30 minutes until approximately 25% of the drug's peak disappeared. The drug was considered stable if its concentration exceeded 90% of the original. RESULTS: For all Dianeal PD-2 peritoneal dialysis solution containing 1.5%, 2.5%, and 4.25% dextrose, cefazolin sodium was considered stable at 38 degrees C for 60 hours at low cefazolin concentrations (125 mg/L), both with and without heparin, and for 48 hours at high cefazolin concentrations (500 mg/L). Cefazolin sodium was considered stable at 38 degrees C in icodextrin for 48 hours at low cefazolin concentrations in heparinized and non-heparinized solutions, and at high concentrations only in non-heparinized dialysate, not in heparinized dialysate. Cefazolin sodium was considered stable at 38 degrees C in icodextrin for 60 hours at high concentrations when heparinized. CONCLUSION: Cefazolin sodium was stable in all four nonheparinized dialysate fluids for at least 48 hours at 38 degrees C. In heparinized icodextrin dialysate, high concentrations of cefazolin sodium were not stable for extended periods of time. Extended use and heating of dialysate containing cefazolin may adversely affect patient outcome.

Cefazolin↗

PubMed2005

Adhesion prevention comparing liquid and solid barriers in the rabbit uterine horn model.

OBJECTIVE: The purpose of this study was to assess the ability of four different either solid or fluid barriers to reduce adhesions in an established model of gynecological surgery. STUDY DESIGN: 50 Chinchilla rabbits underwent bilateral deperitonealization and devascularization of the uterine horns (DUH). Afterwards solid membranes of either hyaluronic acid-carboxymethylcellulose (HA-CMC) or lactide-caprolactone-copolymer (LCC) were placed around the injured uterine horns or fluids (icodextrin (ID) or phospholipids (PL)) were intraperitonealy administered. The control group went without protection. After 10 days, adhesions were measured by planimetry. RESULTS: Phospholipids (median 49.8 mm2) significantly reduced adhesion areas in comparison to all other groups: surgical controls (median 230.6 mm2), HA-CMC (median 194.9 mm2), LCC (median 327.1 mm2), and icodextrin (median 242.1 mm2). CONCLUSIONS: These results prove the efficacy of phospholipids to reduce primary adhesion formation in the Chinchilla double uterine horn model compared to HA-CMC, LCC and icodextrin. Future clinical studies are recommended.

Animals↗

PubMed2000

Transperitoneal transport of glucose in vitro.

The effect of fluid mixing intensification, damage of mesothelial cells, gentamicin, and icodextrin on the diffusive glucose transport across the peritoneal membrane were evaluated in in vitro studies. A mathematical model of mass transport was used to calculate the diffusive permeability, expressed as a diffusive permeability coefficient (P). In the control conditions, the rate of glucose transfer from the interstitial to the mesothelial side of membrane (I-->M) and in the opposite direction (M-->I) remained constant, and the P value at mean was 2,731 +/- 1,493 x 10-4 (cm x s-1). The change of the stirring rate from 5.5 to 11 ml/min increased P values by about 74% for transport direction I-->M and 58% for M-->I, and the change from 11 to 22 ml/min enhanced P at mean by about 42% for both directions. The damage of the mesothelial layer, using sodium deoxycholate (2.5 mmol/L; 103.6 mg%), increased the glucose transfer from the interstitial to the mesothelial side of the peritoneum by 41% and to the opposite direction by 70%. Addition of icodextrin to the glucose solution increased glucose bidirectional transport at mean by about 14% for I-->M and 24% for M-->I. Furthermore, gentamicin did not change the I-->M transfer, but diminished M-->I transport by about 12%. In conclusion, the reduction of unstirred fluid layers at the mesothelium and the interstitium-fluid interfaces, removal of mesothelium, and addition of icodextrin increased the diffusive glucose transport in vitro; unstirred fluid layers restricted glucose transfer (I-->M) more than the mesothelium; and peritoneal glucose transport, directed from the mesothelial to the interstitial side of the peritoneum, decreased slightly after the addition of gentamicin.

Algorithms↗

PubMedDate not supplied

Effects of peritoneal dialysis solutions on the secretion of growth factors and extracellular matrix proteins by human peritoneal mesothelial cells.

OBJECTIVE: To compare the effects of different peritoneal dialysis solutions (PDS) on secretion of vascular endothelial growth factor (VEGF), transforming growth factor-beta1 (TGFbeta1), procollagen I C-terminal peptide (PICP), procollagen III N-terminal peptide (PIIINP), and fibronectin by cultured human peritoneal mesothelial cells (HPMC). DESIGN: Using M199 culture medium as control, commercial PDS containing 1.5% or 4.25% glucose and 40 mmol/L lactate [Dianeal 1.5 (D 1.5) and Dianeal 4.25 (D 4.25), respectively; Baxter Healthcare, Deerfield, Illinois, USA]; PDS containing 1.5% or 4.25% glucose with 25 mmol/L bicarbonate and 15 mmol/L lactate [Physioneal 1.5 (P 1.5) and Physioneal 4.25 (P 4.25), respectively; Baxter]; and PDS containing 7.5% icodextrin [Extraneal (E); Baxter] were tested. Growth-arrested and synchronized HPMC were continuously stimulated for 48 hours by test PDS diluted twofold with M199, TGFbeta1 1 ng/mL, or different concentrations of icodextrin. VEGF, TGFbeta1, and fibronectin secreted into the media were analyzed by ELISA, and PICP and PIIINP by radioimmunoassay. RESULTS: Dianeal 1.5, D 4.25, and P 4.25, but not P 1.5 and E, significantly increased VEGF secretion compared with control M199. D 4.25- and P 4.25-induced VEGF secretion was significantly higher than induction by D 1.5 and P 1.5, respectively, suggesting that high glucose may be involved in the induction of VEGF. Physioneal 1.5- and P 4.25-induced VEGF secretion was significantly lower than induction by D 1.5 and D 4.25, respectively, suggesting a role for glucose degradation products (GDP) in VEGF production. TGFbeta1 secretion was significantly increased by D 4.25 and E. Icodextrin increased TGFbeta1 secretion in a dose-dependent manner. All PDS tested significantly increased secretion of PIIINP compared with control. D 1.5- and D 4.25-induced PIIINP secretion was significantly higher than P 1.5, P 4.25, and E. Physioneal 4.25-induced PIIINP secretion was significantly higher than P 1.5, again implicating high glucose and GDP in PIIINP secretion by HPMC. There was no significant increase in PICP or fibronectin secretion using any of the PDS tested. Addition of TGFbeta1 1 ng/mL into M199 control significantly increased VEGF, PICP, PIIINP, and fibronectin secretion by HPMC. CONCLUSIONS: The present study provides direct evidence that HPMC can secrete VEGF, TGFbeta1, and PIIINP in response to PDS, and that HPMC may be actively involved in the development and progression of the peritoneal membrane hyperpermeability and fibrosis observed in long-term PD patients. This study also suggests that both high glucose and GDP in PDS may play important roles in inducing VEGF and PIIINP production/secretion by HPMC.

Bicarbonates↗

PubMedDate not supplied

Sodium removal in patients undergoing CAPD and automated peritoneal dialysis.

OBJECTIVES: To compare sodium removal in continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) patients, and to identify the main factors that modify Na removal in clinical practice in these patients. DESIGN: Study in three steps. Cross-sectional observational (Study A), and longitudinal interventional (Studies B and C). PATIENTS AND METHODS: First (Study A) we carried out a cross-sectional survey of Na removal in 63 patients on CAPD and 78 patients on APD. Second (Study B), we studied Na removal in 32 patients before and after changing from CAPD to APD therapy. Finally (Study C), we analyzed the impact on Na removal of introducing icodextrin for the long dwell in 16 patients undergoing CAPD or APD. RESULTS: In Study A, total Na removal averaged 210 mmol/day for CAPD patients and 91 mmol/day for APD patients (p < 0.001); Na removal was < 100 mmol/day in 7.1% of CAPD patients and 56.4% of APD patients. Multivariate analysis identified ultrafiltration [B = 125 mmol/day, 95% confidence interval (CI) 110,140], CAPD therapy (B = 60 mmol/day, 95%CI 37, 83), and residual diuresis (B = 51 mmol/L, 95%CI 34, 69) as independent predictors of Na removal (adjusted r2 = 0.76). For APD patients, longer nocturnal dwell times and performing a supplementary diurnal exchange were also independently associated with higher Na removal rates. In Study B, Na removal decreased from 192 to 92 mmol/day (median) after the change to APD (p = 0.02). In Study C, peritoneal Na removal increased from 98 to 148 mmol/day (median) (p = 0.04) after introducing icodextrin. CONCLUSIONS: Standard APD schedules are frequently associated with poor Na removal rates. For any degree of ultrafiltration, Na removal is better in CAPD than in APD. Icodextrin, supplementary diurnal exchanges, and longer nocturnal dwell times improve Na removal in APD. Sodium removal can be estimated from ultrafiltration in patients on CAPD, but must be specifically monitored in patients on APD.

Adult↗