Arachidonic acid and leukotrienes in clinical dermatology

The inter-relation between inflammation and epidermal proliferation in normal skin following epicutaneous application of leukotriene-B4--an immunohistochemical study

Topical application of leukotriene-B4 (LTB4) on normal skin has been used as an in-vivo model to investigate cutaneous inflammation and epidermal proliferation, which are important phenomena in the pathogenesis of psoriasis. The aim of the present investigation is to further elucidate the interrelation between inflammation and epidermal proliferation, using specific monoclonal antibodies as markers for the different cell types involved. Aliquots of LTB4 were applied on the upperarms of eight healthy volunteers. After LTB4-application, biopsies were taken at consecutive time intervals. On frozen sections, epidermal proliferation was assessed by Ks8.12-(keratin 16) and Ki-67-binding (cycling cells), inflammation was characterized using anti-elastase (PMN), T11 (T-lymphocytes), pan-B (B-lymphocytes), WT 14 (CD14-positive cells) and OKT 6 (Langerhans cells). New observations were that the density of CD14-positive cells was increased even at 8 h and decreased slightly at 72 h. A striking rearrangement of Langerhans cells was seen in close vicinity to intra-epidermal accumulations of PMN. Remarkably an increased density of these cells in the dermis at 72 h was seen and a decrease in the epidermis. In line with previous studies, the accumulation of PMN reached a maximum 24 h after LTB4-challenge. The identity of the mononuclear infiltrate cells which have been reported 48-72 h after LTB4 proved to be T-lymphocytes. No B-lymphocytes were observed. Ki-67-positive nuclei were maximally increased 72 h after LTB4-application, which implies that recruitment of cycling cells is of relevance for the LTB4-induced proliferation in vivo. The hyperproliferation-related keratin 16 was expressed inconsistently in the suprabasal compartment.(ABSTRACT TRUNCATED AT 250 WORDS)

A double-blind, placebo-controlled, multicenter trial of lithium succinate ointment in the treatment of seborrheic dermatitis. Efalith Multicenter Trial Group

BACKGROUND

Seborrheic dermatitis, an inflammatory dermatosis that principally affects sebaceous areas, may be related to the presence of the yeast Pityrosporum ovale. Topical therapy with corticosteroids, although in general effective, may be associated with several unwanted effects. The development of alternative non-steroid-based therapies may enable patients to avoid the use of topical steroids and help elucidate the pathogenesis of the disease.

OBJECTIVE

This study aimed to assess the efficacy and safety of an ointment containing 8% lithium succinate in the treatment of seborrheic dermatitis.

METHODS

The study consisted of a multicenter placebo-controlled clinical trial in 227 adult patients.

RESULTS

Lithium succinate ointment was significantly more effective than placebo in treating all the symptoms of seborrheic dermatitis. No specific unwanted effects were associated with its use. Relapse was slow when treatment was stopped.

CONCLUSION

The effectiveness of lithium succinate ointment in the treatment of seborrheic dermatitis adds to the evidence implicating P. ovale in the pathogenesis of that condition.

Arachidonic acid metabolites and colchicine in Behçet's disease (BD)

Vasculitis is accepted to be the basis of Behçet's disease (BD) which is a multisystem disease, and the arachidonic acid(AA) metabolites acting as balancing mediators in the organism are accepted to be responsible for the vasculitis. In this study, we examined the prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) levels of the patients with BD before and after colchicine therapy. We found a statistical decrease in the PGE2 and LTC4 levels after colchicine therapy compared to the previous levels, concluding that colchicine inhibits the inflammation and the polymorphonuclear leukocyte (PML) chemotaxis by inhibiting the cyclooxygenase and lipoxygenase pathways.

Essential fatty acids in clinical dermatology

A deficiency of essential fatty acid intake can produce severe cutaneous abnormalities but is exceedingly rare in clinical practice. Recent research has shown that abnormalities in essential fatty acid metabolism may play a role in atopic eczema, acne, and psoriasis. Therapeutic innovations have already resulted from this knowledge, and more are likely to emerge.