A COMPARISON OF COMEDONAL AND SKIN SURFACE-LIPIDS FROM HAIRLESS DOGS SHOWING CLINICAL SIGNS OF ACNE

[摘要] Certain animals in a colony of hairless dogs (Mexican Hairless .times. Beagle) display the clinical features of acne vulgaris, including both open and closed comedones, milia, pustules and abcesses. In order to compare the canine disease with human acne, lipids from the various types of noninflamed lesions and from the skin surface were analyzed by TLC and gas-liquid chromatography [GLC]. TLC of total nonhydrolyzed lipid from comedones and milia gave similar patterns, with free sterol, ceramides and free fatty acids comprising the bulk of the material and sterol esters and wax diesters as minor components. Skin surface samples contained mainly sterol esters and wax diesters, with smaller amounts of free sterol and only trace amounts of ceramides. GLC analysis of total hydrolyzed fatty acids from comedones showed similar patterns for the various lesion types, with 22-26 carbon acids comprising 55-65% of the total; these acids comprised only 19% of the total hydrolyzed skin surface samples. Analyses by argentation TLC and GLC/mass spectrometry showed the lesional lipids contained significant amounts of .alpha.-hydroxy-16:0, 16:1, 18:1 and 18:2 but only trace amounts of these appeared in the surface lipid. Fatty acid analysis of individual lipid classes show that the long chain, saturated fatty acids occur predominantly in the free fatty acid and polar lipid fractions and not in the wax diester or sterol ester fractions. Since wax diesters and sterol esters are products of sebaceous gland lipid synthesis, whereas free sterols, fatty acids and ceramides are characteristic epidermal lipids, the lipids obtained from the acne lesions of dogs seem primarily epidermal in origin and sebaceous gland contribution seems minimal in plugged follicles.