title: Peritoneal inflammation precedes encapsulating peritoneal sclerosis: results from the GLOBAL Fluid Study.
abstract: BACKGROUND
  Encapsulating peritoneal sclerosis (EPS) is an uncommon condition, strongly associated with a long duration of peritoneal dialysis (PD), which is itself associated with increased fibrosis in the peritoneal membrane. The peritoneal membrane is inflamed during PD and inflammation is often associated with fibrosis. We hypothesized that patients who subsequently develop EPS might have a more inflamed peritoneal membrane during PD.
  
  
  METHODS
  We performed a nested, case-control study identifying all EPS cases in the UK arm of the GLOBAL Fluid Study and matching them by centre and duration of PD with two to three controls. Dialysate and plasma samples were taken during repeated peritoneal equilibration tests prior to cessation of PD from cases and controls. Samples were assayed by electrochemiluminescence immunoassay for interleukin-1β (IL-1β), tumour necrosis factor α (TNF-α), interferon-γ (IFN-γ) and IL-6. Results were analysed by linear mixed models adjusted for age and time on PD.
  
  
  RESULTS
  Eleven EPS cases were matched with 26 controls. Dialysate TNF-α {0.64 [95% confidence interval (CI) 0.23, 1.05]} and IL-6 [0.79 (95% CI 0.03, 1.56)] were significantly higher in EPS cases, while IL-1β [1.06 (95% CI -0.11, 2.23)] and IFN-γ [0.62 (95% CI -0.06, 1.29)] showed a similar trend. Only IL-6 was significantly higher in the plasma [0.42 (95% CI 0.07, 0.78)]. Solute transport was not significantly different between cases and controls but did increase in both groups with the duration of PD.
  
  
  CONCLUSIONS
  The peritoneal cavity has higher levels of inflammatory cytokines during PD in patients who subsequently develop EPS, but neither inflammatory cytokines nor peritoneal solute transport clearly discriminates EPS cases. Increased systemic inflammation is also evident and is probably driven by increased peritoneal inflammation.
authors.affiliation: Department of Nephrology, University Hospitals of North Staffordshire, Royal Infirmary, Princess Road, Stoke on Trent, Staffordshire ST4 7LN, UK.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Lambie
authors.affiliation: Renal Unit, Morriston Hospital, Swansea, UK Institute of Nephrology, Cardiff University School of Medicine, Heath Park, Cardiff, UK.
authors.forename: James
authors.initials: J
authors.lastname: Chess
authors.affiliation: Manchester Institute of Nephrology and Transplantation, Manchester Royal Infirmary, Manchester, UK.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Summers
authors.affiliation: Ipswich Hospital NHS Trust, Ipswich, UK.
authors.forename: Paul Ford
authors.initials: PF
authors.lastname: Williams
authors.affiliation: Institute of Nephrology, Cardiff University School of Medicine, Heath Park, Cardiff, UK Section of Nephrology, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Topley
authors.affiliation: Department of Nephrology, University Hospitals of North Staffordshire, Royal Infirmary, Princess Road, Stoke on Trent, Staffordshire ST4 7LN, UK.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Davies
mesh_terms: D001826:Body Fluids / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism*; D015314:Dialysis Solutions / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D056627:Peritoneal Fibrosis / Q000453:epidemiology / Q000209:etiology / Q000473:pathology*; D010537:Peritoneum / Q000473:pathology*; D010538:Peritonitis / Q000150:complications* / Q000473:pathology; D015995:Prevalence; D012189:Retrospective Studies; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D016207:Cytokines; D015314:Dialysis Solutions
keywords: chronic inflammation; encapsulating peritoneal sclerosis; peritoneal dialysis; peritoneal membrane