title: Limited effect of anti-rheumatic treatment on 15-prostaglandin dehydrogenase in rheumatoid arthritis synovial tissue.
abstract: BACKGROUND
  Rheumatoid arthritis (RA) is a chronic inflammatory disease in which prostaglandin E2 (PGE2) displays an important pathogenic role. The enzymes involved in its synthesis are highly expressed in the inflamed synovium, while little is known about 15- prostaglandin dehydrogenase (15-PGDH) that metabolizes PGE2. Here we aimed to evaluate the localization of 15-PGDH in the synovial tissue of healthy individuals or patients with inflammatory arthritis and determine the influence of common RA therapy on its expression.
  
  
  METHODS
  Synovial tissue specimens from healthy individuals, psoriatic arthritis, ostheoarthritis and RA patients were immunohistochemically stained to describe the expression pattern of 15-PGDH. In addition, the degree of enzyme staining was evaluated by computer analysis on stained synovial biopsies from two groups of RA patients, before and after RA specific treatment with either intra-articular glucocorticoids or oral methotrexate therapy. Prostaglandins derived from the cyclooxygenase (COX) pathway were determined by liquid-chromatography mass spectrometry in supernatants from interleukin (IL) 1β-activated fibroblast-like synoviocytes (FLS) treated with methotrexate.
  
  
  RESULTS
  15-PGDH was present in healthy and inflamed synovial tissue, mainly in lining macrophages, fibroblasts and vessels. Intra-articular glucocorticoids showed a trend towards reduced 15-PGDH expression in RA synovium (p = 0.08) while methotrexate treatment left the PGE2 pathway unaltered both in biopsies ex vivo and in cultured FLS.
  
  
  CONCLUSIONS
  Early methotrexate therapy has little influence on the expression of 15-PGDH and on any of the PGE2 synthesizing enzymes or COX-derived metabolites. Thus therapeutic strategies involving blocking induced PGE2 synthesis may find a rationale in additionally reducing local inflammatory mediators.
authors.affiliation: Department of Medicine, Rheumatology Unit, Karolinska Institute/Karolinska University Hospital Solna, Stockholm, 171 76 Sweden.
authors.forename: Karina Roxana
authors.initials: KR
authors.lastname: Gheorghe
authors.forename: Syed
authors.initials: S
authors.lastname: Sadique
authors.forename: Patrick
authors.initials: P
authors.lastname: Leclerc
authors.forename: Helena
authors.initials: H
authors.lastname: Idborg
authors.forename: Ivonne
authors.initials: I
authors.lastname: Wobst
authors.forename: Anca Irinel
authors.initials: AI
authors.lastname: Catrina
authors.forename: Per-Johan
authors.initials: PJ
authors.lastname: Jakobsson
authors.forename: Marina
authors.initials: M
authors.lastname: Korotkova
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000201:enzymology*; D015153:Blotting, Western; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000096:biosynthesis* / Q000187:drug effects; D007150:Immunohistochemistry; D007270:Injections, Intra-Articular; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage; D008875:Middle Aged; D013583:Synovial Membrane / Q000187:drug effects / Q000201:enzymology*
chemical_list: D018501:Antirheumatic Agents; D005938:Glucocorticoids; D006911:Hydroxyprostaglandin Dehydrogenases; C035859:15-hydroxyprostaglandin dehydrogenase; D008727:Methotrexate