An exploratory study to determine the association between assessed facial skin aging and plasma isoprostane levels in middle-aged Japanese women.

BACKGROUND: One of the central mechanisms of aging is hypothesized to be oxidative stress. Quantification of oxidative stress in human organ systems has been difficult. One of the best methods is using plasma isoprostane levels, which have been shown to reflect oxidative stress in multiple nondermatologic organ systems. OBJECTIVE: To determine whether severity of aging of human skin is associated with plasma isoprostane levels, specifically prostaglandin F2a (PGF2a) and 8-iso-PGF2a while controlling for covariates such as body mass index, ultraviolet light exposure, diet, medication, supplement use, and stress levels. METHODS AND MATERIALS: Facial skin aging assessments performed by four blinded dermatologists were correlated with plasma isoprostane levels in 46 healthy, nonsmoking Japanese women aged 45 to 60. RESULTS: Individuals whose assessed skin age exceeded chronological age had mean plasma isoprostane levels of PGF2a and 8-iso-PGF2a that were higher than those whose skin age was assessed to be less than chronological age (p = .001 and .001, respectively). These results remained statistically significant when adjusted for confounding variables (8-iso-PGF2a, p = .02; PGF2a, p = .03). CONCLUSIONS: Plasma isoprostanes as markers of accelerated aging of the skin merit further study.

The relationship between CD86/CD54 expression and THP-1 cell viability in an in vitro skin sensitization test--human cell line activation test (h-CLAT).

Recent regulations for cosmetics in Europe prohibit animal testing for evaluating the sensitization potential of chemicals to improve animal welfare. Yet, there is not an acceptable Organization for Economic Co-operation and Development non-animal skin sensitization test method. Several in vitro skin sensitization methods that focus on the activation of Langerhans cells, including human cell lines, are being evaluated as possible alternatives. In our previous study, we optimized our human cell line activation test (h-CLAT) using THP-1 cells (monocytic leukemia cell line) and conducted an inter-laboratory study. We found that measuring CD86/CD54 expression may be useful for predicting skin sensitization. The aim of this study was to confirm the relationship between CD86/CD54 expression and THP-1 cell viability in the h-CLAT. In this study, 21 allergens (e.g., dinitrochlorobenzene, p-phenylenediamine, Ni) and 8 non-allergens (e.g., SLS, lactic acid) were evaluated. For each chemical, more than 10 concentrations that gave a predicted cell viability range of 20-95% were used. The data showed that expression patterns of CD86/CD54 differed depending on chemical. For most allergens, cytotoxicity (65-90% cell viability) was needed for enhancement of CD86/CD54 expression. The criteria of "CD86 > or = 150 or CD54 > or = 200" resulted in an accuracy of 93%, which confirms appropriate cut-off criteria for h-CLAT. Furthermore, a good correlation was observed between EC3 of local lymph node assay and EC150(CD86) or EC200(CD54) of h-CLAT (12 or 16 chemicals, respectively), which would provide a useful estimate of allergic potency. These findings suggest that h-CLAT would be a good robust in vitro skin sensitization test.