Induction of leukotriene B4 and prostaglandin E2 release from keratinocytes by protease-activated receptor-2-activating peptide in ICR mice

Anti-Inflammatory Activity of H1 Receptor Antagonist Cetirizine in Animal Models

“…As granuloma represents the exudative and proliferative phases of inflammation, the drugs under study might be acting at these levels thereby reducing the migration of eosinophil's, neutrophils and platelets 33 . The other probable mechanism of cetirizine as an antiinflammatory activity is by release of PGE2 from monocyte and macrophages which are predominant cells in chronic inflammation 34 .One of the main substances released by the mast cells is histamine and since H1 receptor antagonists are being studied, a study on mast cell count has also been carried out to substantiate the results obtained in the chronic model. The H1 receptor antagonist cetirizine has shown anti-inflammatory effects in animal models and it has widest therapeutic window and the lowest potential for dose limiting sedation and cognitive impairment may offer the greatest therapeutic potential for its clinical use 35 .…”

Involvement of Serine Protease and Proteinase-Activated Receptor 2 in Dermatophyte-Associated Itch in Mice

“…Keratinocytes release several itch mediators and itch enhancers, such as leukotriene B 4 Andoh et al, 2001Andoh et al, , 2004Andoh et al, , 2009, thromboxane A 2 (Andoh et al, 2007), and nitric oxide (Andoh and Kuraishi, 2003). Recently, it has been shown that leukotriene B 4 is produced in cultured keratinocytes by stimulation of PAR 2 receptors and that intradermal PAR 2 agonist-induced scratching is suppressed by a 5-lipoxygenase inhibitor in mice (Zhu et al, 2009). These findings taken together raise the possibility that serine proteases secreted by dermatophytes activate PAR 2 receptors in the epidermal keratinocytes to secrete itch mediators including leukotriene B 4 .…”

Eicosanoids and Keratinocytes in Wound Healing

“…9 Murine keratinocytes have been shown to produce LTB4. 10 However, studies in human keratinocytes remain mixed with one study that showed a lack of expression of 5-LOX or the ability for endogenous LTB4 production, 11 while others noted expression of 5-LOX in the epidermis 12 and documented LTB4 13 and 5-HETE release. 13 Regardless, keratinocytes can produce LTB4 in the presence of LTA4 as they express the LTA4 hydrolase necessary for the synthesis of LTB4.…”