RESUMEN
As dietary sources of gamma-linolenic acid [GLA; 18:3(n-6)], borage oil (BO; 24-25 g/100 g GLA) and evening primrose oil (PO; 8-10 g/100 g GLA) are efficacious in treating skin disorders. The triglycerol stereospecificity of these oils is distinct, with GLA being concentrated in the sn-2 position of BO and in the sn-3 position of PO. To determine whether the absolute level and/or the triglycerol stereospecificity of GLA in oils affect biological efficacy, epidermal hyperproliferation was induced in guinea pigs by a hydrogenated coconut oil (HCO) diet for 8 wk. Subsequently, guinea pigs were fed diets of PO, BO or a mixture of BO and safflower oil (SO) for 2 wk. The mixture of BO and SO (BS) diet had a similar level of GLA as PO but with sn-2 stereospecificity. As controls, two groups were fed SO and HCO for 10 wk. Epidermal hyperproliferation was reversed by all three oils in the order of BO > BS > PO. However, proliferation scores of group PO were higher than of the normal control group, SO. The accumulations of dihomo-gamma-linolenic acid [DGLA; 20:3(n-6)], an elongase product of GLA, into phospholipids and ceramides, of 15-hydroxyeicosatrienoic acid (15-HETrE), the potent antiproliferative metabolite of DGLA, and of ceramides, the major lipid maintaining epidermal barrier, in the epidermis of group BO were greater than of groups BS and PO. Group BS had higher levels of DGLA, 15-HETrE and ceramides than group PO. With primary dependence on absolute levels, our data demonstrate that the antiproliferative efficacy of GLA in the epidermis is preferably exerted from sn-2 stereospecificity of GLA in BO.
Asunto(s)
Fármacos Dermatológicos/química , Fármacos Dermatológicos/uso terapéutico , Epidermis/efectos de los fármacos , Enfermedades de la Piel/tratamiento farmacológico , Ácido gammalinolénico/química , Ácido gammalinolénico/uso terapéutico , Acantosis Nigricans/inducido químicamente , Animales , División Celular/efectos de los fármacos , Ceramidas/biosíntesis , Modelos Animales de Enfermedad , Epidermis/química , Epidermis/patología , Ácidos Grasos/análisis , Ácidos Grasos Esenciales/química , Ácidos Grasos Esenciales/uso terapéutico , Cobayas , Hiperplasia/inducido químicamente , Ácidos Linoleicos , Masculino , Oenothera biennis , Aceites de Plantas/química , Aceites de Plantas/uso terapéutico , Aceite de Cártamo , Piel/efectos de los fármacos , Piel/patología , Estereoisomerismo , Resultado del TratamientoRESUMEN
Acanthosis nigricans is well recognized in its clinical association with several types of insulin-resistant syndromes, and skin involvement is usually unresponsive to local treatment or management of diabetes. A young woman with a lipodystrophic form of diabetes, hypertriglyceridemia, and severe generalized acanthosis nigricans was placed on a diet with fat supplementation in the form of omega-3-fatty-acid-rich fish oil. She was observed to have striking improvement in the appearance and extent of acanthosis nigricans while receiving this regimen. This occurred despite continued therapy with niacin (nicotinic acid), an agent associated with acanthosis nigricanslike skin changes.