title: Expression of heat shock protein 72 in peritoneal leukocytes is induced by peritoneal dialysis.
abstract: BACKGROUND
  One of the main limitations of peritoneal dialysis (PD) is deterioration of functional and morphological characteristics of the peritoneum. This complication appears to be related to the low biocompatibility profile of PD fluids. Recently, induction of the heat shock protein (HSP) stress response was demonstrated in cultured human mesothelial cells exposed to PD fluid in vitro. We investigated whether expression of heat shock protein 72 (HSP-72) in peritoneal macrophages is induced upon exposure to PD fluid during continuous ambulatory PD.
  
  
  METHODS
  Peritoneal leukocytes were isolated from 4-hour dwell dialysate; peripheral blood mononuclear cells (PBMC) and peripheral blood monocytes isolated from the same patients were used as a control. In separate experiments, PBMC from healthy individuals were exposed in vitro to different PD fluids or to culture media. Expression of HSP-72 was assessed by Western immunoblotting, flow cytometry, and reverse-transcription polymerase chain reaction analysis.
  
  
  RESULTS
  Macrophages and leukocytes isolated from dialysis effluent expressed significantly increased HSP-72 and mRNA levels compared to blood monocytes and PBMC of the same patients. In vitro exposure of PBMC to fresh PD fluids resulted in significantly higher expression of HSP-72 compared to those incubated in culture medium. PBMC exposed in vitro to standard lactate-buffered dialysis fluids also expressed significantly more HSP-72 compared to cells exposed to bicarbonate/lactate-buffered fluids.
  
  
  CONCLUSIONS
  Our results indicate that exposure to PD fluids during dialysis triggers a shock response in peritoneal cells, which is manifested by significantly increased HSP-72 expression at both protein and mRNA levels. Analysis of this protein expression in peritoneal macrophages could be a new, convenient, and relevant way to assess the biocompatibility of PD fluids ex vivo.
authors.affiliation: Department of Nephrology, Transplantology and Internal Medicine, and Department of Pathophysiology, Medical University of Gdansk, Ul. Debinki 7, 80-211 Gdansk, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Marzec
authors.forename: Tomasz
authors.initials: T
authors.lastname: Liberek
authors.forename: Michal
authors.initials: M
authors.lastname: Chmielewski
authors.forename: Ewa
authors.initials: E
authors.lastname: Bryl
authors.forename: Jacek M
authors.initials: JM
authors.lastname: Witkowski
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Liberek
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Zdrojewski
authors.forename: Boleslaw
authors.initials: B
authors.lastname: Rutkowski
mesh_terms: D015153:Blotting, Western; D017931:DNA Primers; D005260:Female; D005434:Flow Cytometry; D050884:HSP72 Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D010529:Peritoneal Cavity / Q000166:cytology*; D010530:Peritoneal Dialysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D050884:HSP72 Heat-Shock Proteins