title: Effect of two-chambered bicarbonate lactate-buffered peritoneal dialysis fluids on peripheral blood mononuclear cell and polymorphonuclear cell function in vitro.
abstract: Low pH, high osmolality, increasing glucose concentration, and glucose degradation products (GDP) formed during heat sterilization of conventional peritoneal dialysis (PD) fluids have been shown to have a detrimental effect on cells involved in peritoneal host defense. The two-chambered PD fluid bag in which glucose at pH approximately 3 is separated from a bicarbonate (25 mmol/L)-lactate (15 mmol/L) buffer during heat sterilization permits PD fluids with lower GDP to be delivered to the patient at neutral pH. To establish the possible benefit of two-chambered bag PD fluids on peripheral blood mononuclear cell (PBMC) and polymorphonuclear (PMN) cell function, we compared conventional 1.5% Dianeal (1.5%D) with 1.5% two-chambered bag bicarbonate-lactate (1.5%D-B), and conventional 4.25% Dianeal (4.25%D) with 4.25% two-chambered bag bicarbonate-lactate (4.25%D-B). Furthermore, to study the effect of the sterilization process on PBMC and PMN function, we compared filter-sterilized 4.25%D (4.25%D-F) with 4.25%D and 4.25%D-B. PBMC were harvested by Ficoll-Hypaque separation, and 2.5 x 10(6) cells in RPMI were incubated with an equal volume of the test fluids for 4 hours, pelleted, and resuspended in RPMI containing 10 ng endotoxin for a further 20 hours. Tumor necrosis factor alpha (TNF-alpha) production by endotoxin-stimulated PBMC was not significantly different (P = 0.10) between 1.5%D-B and 1.5%D, but was significantly higher (P = 0.01) with 4.25%D-B compared with 4.25%D. PBMC exposed to filter-sterilized fluid (4.25%D-F) showed significantly higher endotoxin-stimulated TNF-alpha production compared with 4.25%D (P = 0.02), but was not significantly different from 4.25%D-B (P = 0.40). PMN were harvested by Ficoll-Hypaque separation and 10 x 10(6) cells incubated with test fluids for 30 minutes. After incubation, phagocytosis (phagocytosis index) was determined by the uptake of 14C-labeled Staphylococcus aureus, oxidative burst by reduction of ferricytochrome C to ferrocytochrome C on stimulation with PMA, and enzyme release by measurement of endotoxin-stimulated bactericidal/permeability increasing protein (BPI). Bicarbonate-lactate two-chambered fluids of similar osmolality and glucose concentration conferred a significant improvement in phagocytosis (P = 0.02 for 1.5%D-B and P < 0.001 for 4.25%D-B). Oxidative burst and BPI release were significantly higher in 4.25%D-B compared with 4.25%D (P < 0.001). Filter-sterilized 4.25%D-F conferred a significant improvement in phagocytosis and oxidative burst compared with 4.25%D (P < 0.001) or 4.25%D-B (P < 0.001). Furthermore, conventional 4.25%D was associated with significantly lower BPI release compared with 4.25%D-F (P = 0.01). GDP's acetaldehyde and 5-HMF were analyzed in 4.25%D-B, 4.25%D, and 4.25%D-F. Acetaldehyde was below the lower limit (0.79 ppm) of the standard curve in 4.25%D-B and 4.25%D-F fluids but was detected (3.76 to 5.12 ppm) in all of the 4.25%D fluids. Relative levels of 5-HMF in the 4.25%D-B (0.032 to 0.041 Abs @ 284 nm) and 4.25%D (0.031 to 0.036 Abs @ 284 nm) were similar. The lowest levels (0.001 Abs @ 284 nm) were observed in the filter-sterilized 4.25%D-F. The beneficial effects of two-chambered bicarbonate lactate-buffered PD fluids on PBMC and PMN function are probably related to reduction of GDP from heat sterilization of glucose in a separate chamber at a lower pH. This improvement in biocompatibility could have a beneficial affect on peritoneal defenses.
authors.affiliation: Division of Nephrology, New England Medical Center, Boston, MA 02111, USA.
authors.forename: S
authors.initials: S
authors.lastname: Sundaram
authors.forename: M
authors.initials: M
authors.lastname: Cendoroglo
authors.forename: L A
authors.initials: LA
authors.lastname: Cooker
authors.forename: B L
authors.initials: BL
authors.lastname: Jaber
authors.forename: D
authors.initials: D
authors.lastname: Faict
authors.forename: C J
authors.initials: CJ
authors.lastname: Holmes
authors.forename: B J
authors.initials: BJ
authors.lastname: Pereira
mesh_terms: D001639:Bicarbonates / Q000494:pharmacology*; D002021:Buffers; D015550:Cell Degranulation / Q000187:drug effects; D002478:Cells, Cultured; D015314:Dialysis Solutions / Q000494:pharmacology*; D006801:Humans; D007552:Isotonic Solutions / Q000494:pharmacology; D007773:Lactates / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000706:statistics & numerical data; D010587:Phagocytosis / Q000187:drug effects; D013481:Superoxides / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000187:drug effects
chemical_list: D001639:Bicarbonates; D002021:Buffers; D015314:Dialysis Solutions; C072670:Hanks Balanced Salt Solution; D007552:Isotonic Solutions; D007773:Lactates; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides