Enzymes involved in the conversion of arachidonic acid to eicosanoids in the skin of atopic dogs.

Canine atopic dermatitis (AD), a chronic inflammatory skin disease, shares characteristics with its human counterpart. To get insight into the role of enzymes involved in production of prostaglandin E(2) (PGE2) and leukotriene B(4) (LTB(4)), potent inflammatory mediators originating from membrane-derived arachidonic acid (AA), expression of genes encoding these enzymes and receptors was quantified by qPCR in non-lesional and lesional skin from atopic dogs and in healthy skin. Significantly higher mRNA expression of the key enzymes 5-lipoxygenase (5-LO), 5-LO activating protein (FLAP), leukotriene A(4) hydrolase (LTA(4)H) and prostaglandin E synthase 1 (mPGES-1) and their receptors (PGE receptors 2 and 3) were observed. Being responsible for elevated levels of metabolites of the 3-series prostaglandins and the 5-series leukotrienes these enzymes may be interesting targets for therapy that should result in amelioration of clinical signs in canine atopic dermatitis.