Ishida K, et al. - In the present study, the researchers desired to know about the pathophysiological linkages between altered ceramide profiles in the stratum corneum (SC) of patients with atopic dermatitis (AD) and their impaired skin barrier and water-holding functions. They analyzed those features following topical treatment with a designed synthetic pseudo-ceramide (pCer) and examined that pathophysiological linkage by microanalyzing ceramides utilizing NPLC-ESI Mass Spectrometry. The pCer level penetrating into the SC was significantly correlated with the water content of the SC but not with TEWL. The level of Cer[NS] and the average carbon chain length of Cer[NS] have been closely associated with the pCer level in the SC. Such results suggest that the penetrated pCer helps change the ceramide profile from an AD to a healthy skin phenotype. Taken together, the observed clinical efficacy of pCer treatment provides a deep insight into the pathogenesis of AD as a ceramide-deficient condition.