Although activity of iron uptake system (IUS) was thought to play an important role in staphylococcal growth in human peritoneal dialysate (HPD) solution, siderophore production, one of the well-known IUS, was not yet detected directly in HPD solution. Therefore, we tried to detect siderophore production directly in HPD solution by using a newly developed chrome azurol S (CAS) agar diffusion assay and to investigate the effect of IUS activity on bacterial growth in HPD solution. According to the susceptibility test for streptonigrin and the productivity of siderophore in the iron-deficient (ID) medium, Staphylococcus aureus ATCC 6538 strain and Staphylococcus epidermidis clinical isolate had higher IUS activity and grew better than S. aureus ATCC 25923 strain in the ID medium. These bacteria did not grow and produce siderophore in the unused chronic ambulatory peritoneal dialysis solution. However, these bacteria grew and produced siderophore in the HPD solution. Moreover, S. aureus ATCC 25923 strain with lower activity of IUS grew poorly and produced smaller amount of siderophore in HPD compared to S. aureus ATCC 6538 strain and S. epidermidis clinical isolate with higher activity of IUS like in the ID medium. To the best of our knowledge, this is the first report that sidero-phore production is directly detected in the HPD by CAS agar diffusion assay. These results indicated that activity of IUS plays an important role in bacterial growth in the HPD solution and pathogenesis of continuous ambulatory peritoneal dialysis peritonitis.
Biological Assay ; Dialysis Solutions/chemistry* ; Drug Contamination ; Human ; Peritoneal Dialysis, Continuous Ambulatory/adverse effects* ; Siderophores/metabolism* ; Staphylococcus/metabolism*

To investigate the effect of nutritional status of continuous ambulatory peritoneal dialysis (CAPD) patients on the development of peritonitis, a cross-sectional study of the nutritional status of 79 CAPD patients and a retrospective study on the incidence of peritonitis in these patients were done. The incidences of peritonitis were compared according to the nutritional status of these patients on CAPD. Protein-caloric malnutrition assessed by a score system based on triceps skinfold thickness, mid-arm circumference, serum albumin level and relative body weight was demonstrated in 27 patients (34%) among 79 total CAPD patients. The incidence of peritonitis was significantly higher in poor nutritional status patients, with 1.09 +/- 0.86/patient-year, than that in normal nutritional status patients with 0.64 +/- 0.72/patient-year (p less than 0.05). In patients with the same nutritional status, patients using Dianeal solution had a trend of a lower incidence of peritonitis than those using Peritosol solution. In conclusion, the nutritional status and possibly the type of CAPD solution may influence CAPD peritonitis as risk factors.
Comparative Study ; Dialysis Solutions/adverse effects ; Female ; Human ; Male ; *Nutritional Status ; Peritoneal Dialysis, Continuous Ambulatory/*adverse effects ; Peritonitis/*etiology ; Support, Non-U.S. Gov't

OBJECTIVES: Recent reports have suggested that patients treated by CAPD have a relatively increased risk of death compared to patients undergoing HD, although the cause of this discrepancy is poorly understood. Protein malnutrition is an important risk factor in ESRD. Also, amino acid concentrations, for which the physiological function differs from that of protein, may be an independent risk factor in ESRD. There is no doubt concerning the prevalence of low amino acid levels in both HD and CAPD patients. But the difference in plasma amino acid levels between these two groups has not been well defined. The purpose of this study is to compare plasma amino acid levels between patients with ESRD on HD and CAPD. METHODS: A cross sectional study of overnight fasting plasma amino acid concentrations was performed on 12 CAPD and 45 HD patients with ESRD, matched by age, sex and body mass index. The levels of individual plasma amino acid and TAA, EAA, NEAA and BCAA were compared for the HD and CAPD groups. In order to measure losses during HD and CAPD, amino acid and protein concentrations were measured from 10 dialysates obtained from 10 HD patients and 12 peritoneal dialysis solutions from 12 CAPD patients. RESULTS: All of the measured amino acid concentrations were found to be lower in the CAPD group compared to the HD group. Furthermore, the levels of TAA (2017.3 +/- 781.1 vs. 903.3 +/- 316.1 mumole/L), EAA(1201.8 +/- 492.6 vs. 567.6 +/- 223.2 mumole/L), NEAA(815.5 +/- 308.6 vs. 335.7 +/- 100.2 mumole/L); and BCAA (315.0 +/- 146.0 vs. 145.2 +/- 65.0 mumole/L), were all lower in the CAPD group than in the HD group. The protein loss was 2.0 +/- 0.2 g/L in the peritoneal dialysate but was not detectable in the hemodialysates. TAA loss over a one week period was about 61.8 +/- 13.0mmole for the HD group and 38.0 +/- 13.0 mmole for the CAPD group. CONCLUSIONS: Our results show that amino acid concentrations are lower in ESRD patients on CAPD than on HD. It seems likely that protein loss in the peritoneal dialysate is a contributing factor to lowered plasma amino acid concentrations in ESRD patients on CAPD than on HD. We believe that the lowered amino acid concentrations observed in CAPD patients may worsen the clinical outcome compared to HD patients.
Adult ; Amino Acids/blood* ; Amino Acids/analysis ; Comparative Study ; Dialysis Solutions/chemistry ; Female ; Human ; Kidney Failure, Chronic/therapy* ; Kidney Failure, Chronic/blood* ; Male ; Middle Age ; Peritoneal Dialysis, Continuous Ambulatory/adverse effects* ; Renal Dialysis*/adverse effects

Cell Line ; Dialysis Solutions ; adverse effects ; Epithelial Cells ; metabolism ; Fibrosis ; Humans ; Peritoneal Dialysis, Continuous Ambulatory ; adverse effects ; Peritoneum ; metabolism ; pathology ; RNA Interference ; RNA, Messenger ; analysis ; RNA, Small Interfering ; pharmacology ; Transforming Growth Factor beta ; antagonists & inhibitors ; genetics ; Transforming Growth Factor beta1

OBJECTIVE: To investigate the mechanism of mitochondrial oxidative injury induced by high glucose peritoneal dialysis solution (PDS) and the protective effect of peroxisome proliferator activated receptor gamma coactivator 1-alpha (PGC-1α) in the mitochondria of human peritoneal mesothelial cells (HPMC) in the high glucose ambience. METHODS: HPMC was cultured in a PDS containing 1.5%, 2.5% and 4.25% glucose for 24 hours. Western blot analysis was used to detect PGC-1α expression. MitoSOX? Red staining, respiratory chain complexes and antioxidant enzyme activities were determined. RESULTS: The activities of respiratory chain complex III and antioxidant enzymes decreased significantly in a concentration- and time-dependent manner, along with the increased production of mitochondrial reactive oxygen species (ROS) and cellular apoptosis. In addition, protein expression of PGC-1α was also decreased in the high glucose PDS ambience. CONCLUSION High glucose PDS might inhibit PGC-1α expression, resulting in the inhibition of mitochondrial function and increase of mitochondrial ROS and cellular apoptosis.
Apoptosis ; Dialysis Solutions ; adverse effects ; Epithelial Cells ; pathology ; Glucose ; adverse effects ; Humans ; Mitochondria ; metabolism ; pathology ; Oxidative Stress ; Peritoneal Dialysis ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; Reactive Oxygen Species ; Transcription Factors ; metabolism

OBJECTIVE: To investigate the effect of different concentrations of glucose peritoneal dialysates (PDS) on monolayer transmesothelial electrical resistance (TER) and migration ability of cultured human peritoneal mesothelial cells (HPMCs) to clarify the cause of peritoneal hyperpermeability state and ultrafiltration failure during prolonged peritoneal dialysis. METHODS: HPMCs were cultured in a 1:1 mixture of DMEM and PDS containing 1.5%, 2.5%, and 4.25% glucose. Methyl thiazolyl tetrazolium (MTT) assay and TER were measured to determine the effect of glucose PDS on the proliferation and permeability of human peritoneal mesothelial monolayers, respectively. Wound-healing assay was used to confirm whether glucose could do harm to the migration of cells. RESULTS: Proliferation of HPMCs was significantly suppressed by different glucose concentrations at 24 hours. TER decreased in a time- and concentration-dependent manner after culture with different concentrations of glucose PDS. Cells lost migration in the presence of high glucose after 24 hours, and most cells lost their normal morphology and became detached from plates after 48 hours of wounding. CONCLUSION High glucose in PDS can cause peritoneal damage by suppressing cell proliferation, inducing increase in paracellular permeability of HPMCs and inhibiting cell migration after damage, which may be responsible for peritoneal hyperpermeability and the development of ultrafiltration failure.
Cell Line ; Cell Membrane Permeability ; drug effects ; Cell Movement ; Electric Impedance ; Epithelium ; metabolism ; Glucose ; adverse effects ; metabolism ; Hemodialysis Solutions ; adverse effects ; Humans ; Peritoneal Dialysis ; Peritoneum ; cytology ; drug effects ; metabolism

OBJECTIVE: To investigate the expression of galectin-1 with the stimulation of peritoneal dialysis solution (PDS) and its role in the epithelial-to-mesenchymal transition (EMT) in human peritoneal mesothelial cells (HPMCs). METHODS: HPMCs were stimulated with PDS containing different concentrations of high glucose (1.5%, 2.5%, and 4.25%). After 24 h, mRNA and protein expressions of galectin-1,vimentin, and zo-1 were analyzed with real-time PCR and Western blot, respectively. Liposome transfected siRNA technique was used to knock down the expression of galectin-1 and the effect of galectin-1 siRNA on the EMT of HPMCs was also observed under 4.25% PDS condition. RESULTS: mRNA expression of galectin-1 in HPMCs increased in PDS groups, especially in group with 4.25% PDS (P<0.05). Protein expression of galectin-1 in HPMCs significantly increased in PDS groups with a dose dependent manner (P<0.05).Expression of vimentin in HPMCs significantly increased in PDS groups, especially in groups of 2.5% PDS and 4.25% PDS (P<0.05), but zo-1 expression markedly decreased (P<0.05). The expression of galectin-1 correlated positively with vimentin (P<0.05) but negatively with zo-1 (P<0.05). Expression of vimentin in groups of 4.25% PDS was markedly inhibited (P<0.05) by galectin-1 siRNA, whereas zo-1 expression was significantly increased (P<0.05). CONCLUSION Galectin-1 can mediate high glucose PDS-induced EMT in HPMCs and may be a new target for the prevention and treatment of peritoneal fibrosis.
Cells, Cultured ; Dialysis Solutions ; pharmacology ; Epithelial Cells ; cytology ; Epithelial-Mesenchymal Transition ; drug effects ; Galectin 1 ; genetics ; metabolism ; Glucose ; pharmacology ; Humans ; Peritoneal Dialysis ; adverse effects ; Peritoneal Fibrosis ; etiology ; Peritoneum ; cytology ; RNA, Messenger ; genetics ; metabolism

BACKGROUND/AIMS: The aim of this study was to evaluate the peritonitis-causing bacteria detected in peritoneal fluid using a blood culture bottle in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). METHODS: One-hundred and eleven dialysates from 43 patients suspected of peritonitis related to CAPD were retrospectively evaluated between May 2000 and February 2008. In all cases, 5 to 10 mL of dialysate was inoculated into a pair of BacT/Alert blood culture bottles, and 50 mL of centrifuged dialysate was simultaneously inoculated into a solid culture media for conventional culture. The results were compared to those of the conventional culture method. Isolated microorganisms were compared between the two methods. RESULTS: The blood culture method was positive in 78.6% (88 / 112) of dialysate specimens and the conventional culture method in 50% (56 / 112, p < 0.001). CONCLUSIONS: The blood culture method using the BacT/Alert system is useful for culturing dialysates and improves the positive culture rate in patients with suspected peritonitis compared to the conventional culture method.
Culture Media ; Dialysis Solutions ; Gram-Negative Bacterial Infections/*diagnosis/microbiology ; Gram-Positive Bacterial Infections/*diagnosis/microbiology ; Humans ; Kidney Failure, Chronic/*therapy ; Microbiological Techniques/*methods ; Peritoneal Dialysis, Continuous Ambulatory/*adverse effects ; Peritonitis/*diagnosis/microbiology ; Sensitivity and Specificity

BACKGROUND: Patients on continuous ambulatory peritoneal dialysis (CAPD) have increased risk of low-turnover bone disease and relative hypoparathyroidism. Recently, it has been believed that magnesium plays an important role in regulating secretion of parathyroid hormone (PTH). The aim of this study was to evaluate the relationship between serum PTH and serum magnesium as a factor increasing the frequency of relative hypoparathyroidism. METHODS: We analyzed the data of 56 patients who had been on CAPD for more than 6 months without any significant problems. No patient had been previously treated with vitamin D or aluminum hydroxide. The patients had used peritoneal dialysate with the magnesium concentration of 0.5 mEq/L. Biochemical parameters, such as BUN, creatinine, alkaline phosphatase bony isoenzyme, total protein, albumin, total calcium, ionized calcium and intact parathyroid hormone level were measured. RESULTS: The mean serum magnesium level was 1.99 +/- 0.36 mEq/L. Among total 56 patients, 15 patients (26.8%) showed hypermagnesemia (serum magnesium > 2.2 mEq/L) and 5 patients (8.9%) showed hypomagnesemia (serum magnesium < 1.6 mEq/L). Among all 56 patients, serum iPTH (intact PTH) level was not correlated with serum magnesium level. However, it was inversely correlated with serum total calcium and ionized calcium levels, respectively (r=-0.365, p=0.006; r=-0.515 p < 0.001). Among 49 patients whose serum iPTH level was less than 300 pg/mL, serum iPTH level was inversely correlated with serum magnesium level (r=-0.295, p=0.039) and inversely correlated with serum total calcium and ionized calcium levels, respectively (r=-0.546, p < 0.001; r=-0.572 p < 0.001). Among 49 patients whose serum iPTH level was less than 300 pg/mL, lower iPTH group (serum iPTH < 120 pg/mL) showed higher serum magnesium level (p=0.037), higher serum total calcium level (p < 0.001) and lower bone isoenzyme of alkaline phosphatase level (p < 0.001) than those of higher iPTH group (120 pg/mL Adult ; Alkaline Phosphatase/blood ; Calcium/blood ; Dialysis Solutions ; Female ; Human ; Kidney Failure, Chronic/complications/therapy ; Magnesium/*blood ; Male ; Middle Age ; Parathyroid Hormones/*blood ; Peritoneal Dialysis, Continuous Ambulatory/*adverse effects/methods ; Phosphates/blood ; Renal Osteodystrophy/etiology

To investigate the role of glucose transporter 1 (GLUT1) and sodium-glucose cotransporter 1 (SGLT1) in high glucose dialysate-induced peritoneal fibrosis.Thirty six male SD rats were randomly divided into 6 groups (6 in each):normal control group, sham operation group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorizin group (PD+Z group), PD+phloretin+phlorizin group (PD+T+Z group). Rat model of uraemia was established using 5/6 nephrotomy, and 2.5% dextrose peritoneal dialysis solution was used in peritoneal dialysis. Peritoneal equilibration test was performed 24 h after dialysis to evaluate transport function of peritoneum in rats; HE staining was used to observe the morphology of peritoneal tissue; and immunohistochemistry was used to detect the expression of GLUT1, SGLT1, TGF-β1 and connective tissue growth factor (CTGF) in peritoneum. Human peritoneal microvascular endothelial cells (HPECs) were divided into 5 groups:normal control group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorezin group (PD+Z group), and PD+phloretin+phlorezin group (PD+T+Z group). Real time PCR and Western blotting were used to detect mRNA and protein expressions of GLUT1, SGLT1, TGF-β1, CTGF in peritoneal membrane and HPECs., compared with sham operation group, rats in PD group had thickened peritoneum, higher ultrafiltration volume, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly increased (all<0.05); compared with PD group, thickened peritoneum was attenuated, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly decreased in PD+T, PD+Z and PD+T+Z groups (all<0.05). Pearson's correlation analysis showed that the expressions of GLUT1, SGLT1 in peritoneum were positively correlated with the expressions of TGF-β1 and CTGF (all<0.05)., the mRNA and protein expressions of GLUT1, SGLT1, TGF-β1, CTGF were significantly increased in HPECs of peritoneal dialysis group (all<0.05), and those in PD+T, PD+Z, and PD+T+Z groups were decreased (all<0.05). Pearson's correlation analysis showed that the expressions of GLUT1, SGLT1 in HPECs were positively correlated with the expressions of TGF-β1 and CTGF (all<0.05).High glucose peritoneal dialysis fluid may promote peritoneal fibrosis by upregulating the expressions of GLUT1 and SGLT1.
Animals ; Cells, Cultured ; Connective Tissue Growth Factor ; analysis ; drug effects ; Dialysis Solutions ; adverse effects ; chemistry ; pharmacology ; Gene Expression Regulation ; drug effects ; Glucose ; adverse effects ; pharmacology ; Glucose Transporter Type 1 ; analysis ; drug effects ; physiology ; Hemodiafiltration ; adverse effects ; methods ; Humans ; Male ; Peritoneal Dialysis ; adverse effects ; methods ; Peritoneal Fibrosis ; chemically induced ; genetics ; physiopathology ; Peritoneum ; chemistry ; drug effects ; pathology ; Phloretin ; Phlorhizin ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; Sodium-Glucose Transporter 1 ; analysis ; drug effects ; physiology ; Transforming Growth Factor beta1 ; analysis ; drug effects ; Uremia ; chemically induced