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Complex roles of cyclo-oxygenase 2 in hepatitis
  1. Andrew P Holt,
  2. David H Adams
  1. Liver Research Group, MRC Centre for Immune Regulation, The University of Birmingham Medical School, Birmingham, UK
  1. Correspondence to:
    Professor D Adams
    Liver Research Group, 5th Floor IBR, The University of Birmingham Medical School, Wolfson Drive, Edgbaston, Birmingham B152TT, UK;d.h.adams{at}

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There is currently insufficient evidence to support the use of COX-2 inhibitors in treating chronic hepatitis or in preventing liver fibrosis

There is a bark of an English tree, which I have found to be a powerful astringent, very efficacious in curing agues and intermitting disorders.1

So wrote the Reverend Edmund Stone in 1763 in a letter to the Royal Society wherein he described his success in treating patients with fever with an extract of powdered willow bark. Although willow extract was used in many ancient cultures as an antipyretic, the active component, salicylic acid, was not identified until the 19th century. The discovery of the chemical structure of salicylate by Herman Kolbe paved the way for the synthesis of acetylsalicylic acid by Bayer in the late 19th century. The mechanism by which it exerted its anti-inflammatory effects remained a mystery until John Vane revealed in the 1970s that aspirin and the newly developed non-steroidal anti-inflammatory drugs (NSAIDs) are non-selective inhibitors of cyclo-oxygenase (COX), the enzyme that catalyses the formation of prostaglandins from arachidonic acid. The enzyme contains two active sites, a cyclo-oxygenase which converts arachidonic acid to prostaglandin G2 (PGG2), and a haem with peroxidase activity which reduces PGG2 to the type-2 prostanoid precursor PGH2, which is subsequently converted into biologically active molecules including the classical prostaglandins (PGE2, PGD2 and PGJ2), prostacyclin and thromboxane-A2.

Three COX isoenzymes have been described, COX1, COX2 and COX3, a splice variant of COX1. COX1 and COX2 display 60% homology at the amino acid level and are both membrane proteins located primarily in the endoplasmic reticulum (COX1) and perinuclear envelope (COX2). COX1 is constitutively expressed in most tissues and is responsible for many cytoprotective and physiological functions. COX2 expression is negligible in …

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  • Competing interests: None.

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