title: Associations among plasma vitamin C, epidermal ceramide and clinical severity of atopic dermatitis.
abstract: OBJECTIVE
  Atopic dermatitis (AD), a chronic inflammatory skin disease, is accompanied by disruption of the epidermal lipid barrier, of which ceramide (Cer) is the major component. Recently it was reported that vitamin C is essential for de novo synthesis of Cer in the epidermis and that the level of vitamin C in plasma is decreased in AD. The objective of this study was to determine the associations among clinical severity, vitamin C in either plasma or epidermis, and Cer in the epidermis of patients with AD.
  
  
  METHODS
  A total of 17 patients (11 male and 6 female) aged 20-42 years were enrolled. The clinical severity of AD was assessed according to the SCORAD (SCORing Atopic Dermatitis) system. Levels of vitamin C were determined in plasma and biopsies of lesional epidermis. Levels of epidermal lipids, including Cer, were determined from tape-stripped lesional epidermis.
  
  
  RESULTS
  The clinical severity of patients ranged between 0.1 and 45 (mild to severe AD) based on the SCORAD system. As the SCORAD score increased, the level of vitamin C in the plasma, but not in the epidermis, decreased, and levels of total Cer and Cer2, the major Cer species in the epidermis, also decreased. There was also a positive association between level of vitamin C in the plasma and level of total Cer in the epidermis. However, levels of epidermal total lipids including triglyceride, cholesterol, and free fatty acid (FFA) were not associated with either SCORAD score or level of vitamin C in the plasma of all subjects.
  
  
  CONCLUSIONS
  As the clinical severity of AD increased, level of vitamin C in the plasma and level of epidermal Cer decreased, and there was a positive association between these two parameters, implying associations among plasma vitamin C, epidermal Cer, and the clinical severity of AD.
authors.affiliation: Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin, Gyeonggi 17104, Korea.
authors.forename: Jihye
authors.initials: J
authors.lastname: Shin
authors.affiliation: Department of Nutritional Science and Food Management, College of Health Sciences, Ewha Womans University, Seoul 03760, Korea.
authors.forename: You Jin
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Nutritional Science and Food Management, College of Health Sciences, Ewha Womans University, Seoul 03760, Korea.
authors.forename: Oran
authors.initials: O
authors.lastname: Kwon
authors.affiliation: Department of Dermatology, College of Medicine, Kyung Hee University, Seoul 02447, Korea.
authors.forename: Nack-In
authors.initials: NI
authors.lastname: Kim
authors.affiliation: Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin, Gyeonggi 17104, Korea.
authors.forename: Yunhi
authors.initials: Y
authors.lastname: Cho
keywords: Atopic dermatitis; ceramide; clinical severity; vitamin C