6-ketoprostaglandin-f1-alpha and Osteoarthritis

We assessed the effects of nabumetone, sulindac, and placebo on renal function and renal excretion of vasodilatory prostaglandins in older female patients (age >50 years) with osteoarthritis and normal renal function. Using a prospective, crossover design, we compared the effects of nabumetone 2000 mg/d and sulindac 400 mg/d with placebo on glomerular filtration rate (GFR), renal plasma flow (RPF), and urinary excretion of prostaglandin E2 and 6-keto-prostaglandin F1alpha in 12 patients. Urinary excretion of vasodilatory prostaglandins was not decreased after 14 days of treatment with either nabumetone or sulindac. Likewise, treatment with nabumetone or sulindac did not significantly alter renal function compared with placebo. There were no differences in mean changes in GFR or RPF from baseline after treatment with nabumetone or sulindac compared with placebo. The mean (+/- SD) changes in GFR from baseline were 0%+/-8% in patients receiving nabumetone, -8%+/-15% in patients receiving sulindac, and -7%+/-15% in patients receiving placebo. The results of this study demonstrate that treatment with nabumetone or sulindac caused no deterioration in renal function in older female patients with osteoarthritis and normal renal function.

Topics: 6-Ketoprostaglandin F1 alpha; Anti-Inflammatory Agents, Non-Steroidal; Butanones; Cross-Over Studies; Dinoprostone; Female; Glomerular Filtration Rate; Humans; Kidney; Nabumetone; Osteoarthritis; Placebos; Potassium; Prospective Studies; Renal Circulation; Sodium; Sulindac

Prostaglandin E synthase (PGES) including isoenzymes of membrane-associated PGES (mPGES)-1, mPGES-2, and cytosolic PGES (cPGES) is the recently identified terminal enzyme of the arachidonic acid cascade. PGES converts prostaglandin (PG)H2 to PGE2 downstream of cyclooxygenase (COX). We investigated the expression of PGES isoenzyme in articular chondrocytes from patients with osteoarthritis (OA). Chondrocytes were treated with various cytokines and the expression of PGES isoenzyme mRNA was analyzed by the reverse transcription-polymerase chain reaction and Northern blotting, whereas Western blotting was performed for protein expression. The subcellular localization of mPGES-1 was determined by immunofluorescent microscopy. Conversion of arachidonic acid or PGH2 to PGE2 was measured by enzyme-linked immunosorbent assay. Finally, the expression of mPGES-1 protein in OA articular cartilage was assessed by immunohistochemistry. Expression of mPGES-1 mRNA in chondrocytes was significantly induced by interleukin (IL)-1beta or tumor necrosis factor (TNF)-alpha, whereas other cytokines, such as IL-4, IL-6, IL-8, IL-10, and interferon-gamma, had no effect. COX-2 was also induced under the same conditions, although its pattern of expression was different. Expression of cPGES, mPGES-2, and COX-1 mRNA was not affected by IL-1beta or TNF-alpha. The subcellular localization of mPGES-1 and COX-2 almost overlapped in the perinuclear region. In comparison with 6-keto-PGF1alpha and thromboxane B2, the production of PGE2 was greater after chondrocytes were stimulated by IL-1beta or TNF-alpha. Conversion of PGH2 to PGE2 (PGES activity) was significantly increased in the lysate from IL-1beta-stimulated chondrocytes and it was inhibited by MK-886, which has an inhibitory effect on mPGES-1 activity. Chondrocytes in articular cartilage from patients with OA showed positive immunostaining for mPGES-1. These results suggest that mPGES-1 might be important in the pathogenesis of OA. It might also be a potential new target for therapeutic strategies that specifically modulate PGE2 synthesis in patients with OA.

Topics: 6-Ketoprostaglandin F1 alpha; Cartilage, Articular; Cells, Cultured; Chondrocytes; Cyclooxygenase 2; Cytokines; Humans; Indoles; Inflammation; Interleukin-1; Intramolecular Oxidoreductases; Isoenzymes; Membrane Proteins; Osteoarthritis; Phenotype; Prostaglandin-E Synthases; Prostaglandin-Endoperoxide Synthases; RNA, Messenger; Thromboxane B2; Time Factors; Up-Regulation

The pharmacological profile of a novel dual inhibitor, tepoxalin and of its carboxylic acid metabolite on cyclooxygenase and lipoxygenase pathways was evaluated by in vitro incubation with synovial tissue. Tissue specimens obtained at surgery in rheumatoid arthritis (RA, n = 10) or osteoarthritis (OA, n = 11) patients were incubated. Tepoxalin (10(-7), 10(-6), 10(-5) M) decreased eicosanoid release calculated in % of tyrode control for OA: LTC4 to 71-33%, 6-keto-PGF1a to 37-20%, PGE2 to 29-6%. For RA: LTC4 to 56-22%, 6-keto-PGF1a to 43-22%, PGE2 to 57-32%. Similarly, its metabolite (10(-7), 10(-5)M) decreased release in OA: LTC4 to 99 and 60%, PGE2 to 42 and 20%, 6-keto-PGF1a to 54 and 25%. In RA:LTC4 to 81 and 45%, PGE2 to 61 and 30%, 6-keto-PGF1a to 46 and 18%. Significance (P < 0.05) was achieved for all but 1 group (LTC4 metabolite at 10(-7)M vs tyrode). In summary a marked and dose dependent decrease of LT and PG release was obtained when incubating the dual inhibitor tepoxalin and its active carboxylic acid metabolite with synovial tissue at doses expected to be reached in the joint during therapy.

Topics: 6-Ketoprostaglandin F1 alpha; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Calcium; Dinoprostone; Eicosanoids; Humans; Leukotriene C4; Organ Culture Techniques; Osteoarthritis; Pyrazoles; Synovial Membrane

The effects of sulfasalazine (SASP) and its metabolites sulfapyridine (SP) and 5-aminosalicylic acid (5-ASA) were investigated on release of prostaglandins (PG) and leukotrienes (LT) from synovial tissue of 37 patients with osteoarthritis, chondrocalcinosis and rheumatoid arthritis. Calcium ionophore A23187 significantly increased the release of PGE2, 6-keto-PGF1 alpha, LTB4, and LTC4 from human synovial tissue irrespective of the underlying joint disease. SASP inhibited release of LTC4 and increased release of PGE2. On the other hand, 5-ASA and SP inhibited the release of all eicosanoids measured. The effective concentrations of SASP and SP were found to be in the range which can be reached during SASP therapy. On the other hand, blood and synovial fluid levels of 5-ASA are considerably lower than those which inhibit eicosanoid synthesis in vitro. While nonsteroidal anti-inflammatory drugs, which are used for symptomatic therapy of rheumatoid arthritis, inhibit cyclooxygenase only, SP, the active metabolite of the second line anti-rheumatic drug SASP, inhibits both PG and LT release. Inhibition of LT synthesis by SASP and SP could contribute to the second line efficacy of SASP therapy in rheumatoid arthritis.

Topics: 6-Ketoprostaglandin F1 alpha; Aminosalicylic Acids; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Chondrocalcinosis; Culture Techniques; Dinoprostone; Humans; Knee Joint; Leukotriene B4; Leukotrienes; Mesalamine; Osteoarthritis; Prostaglandins; SRS-A; Sulfapyridine; Sulfasalazine; Synovial Membrane