title: Biocompatibility and buffers: effect of bicarbonate-buffered peritoneal dialysis fluids on peritoneal cell function.
abstract: BACKGROUND
  Conventional peritoneal dialysis fluids (PDF) have been shown to compromise the function of both leukocytes and human peritoneal mesothelial cells (HPMC). Various in vitro studies have identified the low initial pH in combination with high lactate content, as well as the hyperosmolality and high glucose concentration present in currently used solutions as the primary determinants of their bioincompatibility. Bicarbonate buffered PDF (at neutral pH) display improved in vitro biocompatibility as compared to conventional, lactate buffered PDF. However, little information is currently available regarding the potential impact of PDF on the function of human peritoneal fibroblasts (HPFB), the major cell population present in peritoneal interstitium.
  
  
  METHODS
  The current study compares the effect of bicarbonate and lactate buffered PDF in a model system of resting peritoneal mesothelial cells and fibroblasts cultured from human omentum. Interleukin-1 beta-stimulated IL-6 release from HPMC and HPFB was used as the cell functional parameter.
  
  
  RESULTS
  While short (30 min) pre-exposure to lactate buffered PDF significantly reduced the IL-1 beta-stimulated IL-6 release from HPMC during a subsequent recovery period (24 hr), a significant decrease in HPMC IL-6 secretion with bicarbonate buffered PDF was only observed after prolonged (> or = 60 min) exposure. In contrast, no significant IL-6 inhibition was detected with HPFB pre-exposed to PDF for up to 90 minutes. A significant suppression of HPFB IL-6 secretion was only observed in coincubation experiments (24 hr) with dilutions of both types of PDF.
  
  
  CONCLUSIONS
  These results indicate that (i) bicarbonate buffered PDF are less inhibitory to peritoneal cell function as compared to conventional, lactate buffered PDF; and (ii) HPFB may be more resistant than HPMC to bioincompatible PDF.
authors.affiliation: Department of Nephrology and Intensive-Care Medicine, Universitätsklinikum Charité, Medizinische Fakultät, Humboldt-Universität zu Berlin, Germany. achim.joerres@charite.de
authors.forename: A
authors.initials: A
authors.lastname: Jörres
authors.forename: T O
authors.initials: TO
authors.lastname: Bender
authors.forename: A
authors.initials: A
authors.lastname: Finn
authors.forename: J
authors.initials: J
authors.lastname: Witowski
authors.forename: S
authors.initials: S
authors.lastname: Fröhlich
authors.forename: G M
authors.initials: GM
authors.lastname: Gahl
authors.forename: U
authors.initials: U
authors.lastname: Frei
authors.forename: H
authors.initials: H
authors.lastname: Keck
authors.forename: J
authors.initials: J
authors.lastname: Passlick-Deetjen
mesh_terms: D001639:Bicarbonates / Q000008:administration & dosage* / Q000494:pharmacology; D001672:Biocompatible Materials / Q000494:pharmacology*; D002021:Buffers; D002478:Cells, Cultured; D015314:Dialysis Solutions / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D010529:Peritoneal Cavity / Q000166:cytology / Q000502:physiology*; D010530:Peritoneal Dialysis; D013997:Time Factors
chemical_list: D001639:Bicarbonates; D001672:Biocompatible Materials; D002021:Buffers; D015314:Dialysis Solutions; D015850:Interleukin-6