ISSN:
1432-069X
Keywords:
Leukotriene B4
;
Platelet-activating factor
;
Cutaneous inflammation
;
Eicosanoids
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Acute inflammatory reactions are characterized by leukocyte infiltration associated with increases in vascular permeability and in local blood flow. Leukocyte infiltration can be induced by chemotactic factors such as leukotriene B4 (LTB4) and paf-acether (formely known as platelet-activating factor) that can be generated within inflammatory lesions. Vascular permeability and increase in blood flow are also affected by LTB4 and paf-acether, as well as by several other substances, including histamine and prostaglandins. Derived from arachidonic acid via the 5 lipo-oxygenase pathway, LTB4 is one of the most potent leukocyte chemotactic substances known. Intradermal injections of LTB4 induce dermal neutrophil infiltration in animal models and in humans. Topical application of LTB4 to human skin induces intraepidermal micro-abscesses containing numerous intact neutrophils. LTB4 has been found to be increased in psoriatic lesions, but its synthesis by epidermal cells remains undecided. Like other leukotrienes, LTB4 can stimulate DNA synthesis in cultured human epidermal keratinocytes. However, receptors for LTC4 but not for LTB4 have been found on human keratinocytes in culture. Paf-acether is an ether-linked phospholipid identified as 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine and is considered to be one of the most potent mediators of acute allergic and inflammatory reactions. For instance, intradermal injection of pafacether induces inflammatory events such as neutrophil infiltration and increase in vascular permeability. Recent data suggest that cutaneous cells, such as fibroblasts and keratinocytes, are capable of producing paf and that paf is released during the development of allergic cutaneous reactions. Paf is also increased in psoriatic lesions, and it is tempting to speculate that paf may contribute to the development of various skin disorders with acute and chronic skin inflammation. In the future, LTB4 and paf antagonists might help in providing an answer to the hypothesis that these two mediators may have a key role in many chronic inflammatory skin diseases and may offer new prospects for topical and systemic treatments.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00638234
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