Fumiko Yasukawa

Identification of Ketoconazole as an AhR-Nrf2 Activator in Cultured Human Keratinocytes: The Basis of Its Anti-Inflammatory Effect

Ketoconazole (KCZ) has been shown to exhibit anti-inflammatory effects in addition to its inhibitory effects against fungi; however, the underlying molecular mechanism remains poorly understood. Aryl hydrocarbon receptor (AhR), a receptor that is activated by polycyclic aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons such as dioxin, is a sensor of the redox system against oxidative stress and regulates nuclear factor-erythroid 2-related factor-2 (Nrf2), a master switch of the redox machinery. To clarify whether KCZ modulates AhR-Nrf2 function leading to redox system activation, cultured human keratinocytes were treated with KCZ. Confocal microscopic analysis revealed that KCZ induced AhR nuclear translocation, resulting in the upregulation of CYP1A1 mRNA and protein expression. Furthermore, KCZ actively switched on Nrf2 nuclear translocation and quinone oxidoreductase 1 expression. Tumor necrosis factor-α- and benzo(a)pyrene (BaP)-induced reactive oxidative species (ROS) and IL-8 production were effectively inhibited by KCZ. Knockdown of either AhR or Nrf2 abolished the inhibitory capacity of KCZ on ROS and IL-8 production. In addition, KCZ-induced Nrf2 activation was canceled by AhR knockdown. Moreover, KCZ inhibited BaP-induced 8-hydroxydeoxyguanosine and IL-8 production. In conclusion, the engagement of AhR by KCZ exhibits the cytoprotective effect mediated by the Nrf2 redox system, which potently downregulates either cytokine-induced (AhR-independent) or PAH-induced (AhR-dependent) oxidative stress.

Maternal exposure to high levels of dioxins in relation to birth weight in women affected by Yusho disease

BACKGROUND Studies on the association of maternal exposure to polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) with decreased birth weight in humans have produced conflicting results. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease. OBJECTIVE The Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on birth weight. METHODS Blood samples, obtained from 101 Yusho women (190 births) who gave birth after exposure, were analyzed for congeners of seven PCDDs, ten PCDFs, and four non-ortho PCBs. RESULTS Total PCDD TEQ (adjusted beta=-161.9g; 95% CI, -265.3 to -58.6), total PCDF TEQ (adjusted beta=-105.9g; 95% CI, -179.5 to -32.2), and total non-ortho PCBs (adjusted beta=-178.4g; 95% CI, -318.3 to -38.5) levels were inversely associated with birth weight. Significant inverse associations with birth weight were also found for total PCDD TEQ, total PCDF TEQ, and total non-ortho PCB TEQ levels among male, but not female, infants. Significant inverse associations with birth weight were also found for nine congeners among all infants; the adjusted beta coefficients were largest for 1,2,3,6,7,8-HxCDD and smallest for 2,3,4,7,8-PeCDF. CONCLUSION In the setting of exposure to high levels of dioxins, maternal blood levels of PCDDs, PCDFs and PCBs are associated with lower birth weight in Yusho patients. The association exhibited gender-specific differences, as male infants are more susceptible than females to growth restriction induced by in utero dioxin exposures.

Role of the Arylhydrocarbon Receptor in Lung Disease

Ubiquitous environmental contaminants such as dioxins have long been implicated in cellular toxicity, but only recently have various biological effects been linked to immune regulation. These plentiful noxious agents exert their effects through the arylhydrocarbon receptor (AhR) recognized as a ligand-activated transcription factor. AhR activation mediates gene alteration, cell-cell adhesion interaction, cytokine expression, and mucin production, which are involved in the induction of cancer or inflammation. We have reported that human bronchial epithelial cells express AhR, and AhR activation induces mucin production through reactive oxygen species. This review discusses the role of AhR in lung disease, focusing in particular on airway epithelial cells. In addition, although it is not yet clear how the activation of AhR modifies carcinogenesis or airway inflammation, we mention a potent therapeutic target for AhR activation in the prevention/treatment of lung cancer, allergic asthma, and chronic obstructive pulmonary disease.

Blood levels of PCDDs, PCDFs, and coplanar PCBs in Yusho mothers and their descendants: Association with fetal Yusho disease

Maternal exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) may result in adverse health effects in their children. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease. Yusho mothers delivered descendants with low birth weights and hyperpigmented skin and mucosa, which are characteristic of fetal Yusho disease (FYD). The Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on the development of FYD. Blood samples, obtained from 64 Yusho mothers (117 descendants: 10 with FYD and 107 without FYD), were analyzed for congeners of seven PCDDs, 10 PCDFs, and four coplanar PCBs. We investigated the association between the maternal estimated blood levels of dioxins at delivery and the risk of fetal Yusho disease. We also studied the differences in dioxin blood levels in 24 mother-descendant pairs (5 with FYD and 19 without FYD). The estimated levels of total PCDD TEQ, total PCDF TEQ, total coplanar PCB TEQ, and total TEQ in the maternal blood at delivery were associated with significantly increased risk of FYD. The odds ratios, which present the risk of FYD for a 10-fold increase in blood dioxin, were largest for 1,2,3,6,7,8-HexaCDD (odds ratio=28.6, 95% confidence interval=1.67-489.9, p=0.02). The levels of 1,2,3,6,7,8-HexaCDD in both the Yusho mothers and their descendants with FYD were higher than the levels in those without FYD. These findings suggest that 1,2,3,6,7,8-HexaCDD is the most important causative congener for the development of FYD.

Comparison of the concentrations of polychlorinated biphenyls and dioxins in mothers affected by the Yusho incident and their children

Accumulated maternal dioxins are passed onto the fetus and neonate via the placenta and maternal milk. In Japan in 1968, an accidental human exposure to rice oil contaminated with polychlorinated biphenyls (PCBs) and other dioxin-related compounds, such as polychlorinated dibenzofurans (PCDFs), led to development of Yusho oil disease. We investigated differences in blood dioxin concentrations in mother-children pairs affected by the Yusho incident. From 2002 to 2008, blood samples were collected from 26 pairs of Yusho mothers and their children (19 mothers, 26 children). Specific congeners of seven polychlorinated dibenzo-p-dioxins (PCDDs), ten PCDFs, and four non-ortho PCBs were analyzed. The children had significantly lower TEQ concentrations of PCDDs, PCDFs, and coplanar PCBs compared to their mothers. The mother-child difference in blood concentrations varied with the congeners; the largest for 2,3,4,7,8-pentaCDF and the smallest for 1,2,3,4,6,7,8-heptaCDD. The level for 2,3,4,7,8-pentaCDF, which characterizes Yusho oil disease, was approximately 17-30 times higher in the mothers than in the general population, whereas there were no significant differences between children in the formula-fed group and the general population. In contrast, the mean level for 2,3,4,7,8-pentaCDF in the breast-fed group was approximately 1.5 times, (range 0.5-6.5 times) higher than that in the general population. Over 30 years after the Yusho incident, the mean blood dioxin levels in the offspring were only a fraction of the levels in their mothers. This is more consistent with exposure via breast milk than via transplacental transfer in the Yusho incident.

Sex ratio in two generations of the Yusho cohort.

To the Editor: The number of male births has decreased in many industrialized countries in recent decades. Environmental factors are one possible explanation for these trends. Parental exposure to dioxins or dioxin-like compounds has been associated with reduction in the proportion of male births, suggesting that the predominance of females may be a transgenerational effect of exposure. In Japan, human exposure in 1968 to rice oil contaminated with polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) resulted in a constellation of symptoms called Yusho disease. We investigated whether parental exposure to this contamination affected the sex ratio in offspring (F1; first generation), as well as in their offspring (F2; second generation). In April 2009, we obtained the data on sex and birth date of all children born to a cohort of 1420 people officially registered as having Yusho disease, based on the Diagnostic Criteria for Yusho. The local ethics committee approved the study. Analyses were restricted to parents who had at least one child born after 1968. Sex ratios (proportion of male births) were assessed in 2 generations of offspring born to 217 mothers and 220 fathers. A reduction in offspring sex ratio was observed only when parents were exposed before 20 years of age. Therefore, the analysis was repeated on this subset of 115 mothers and 106 fathers. A 2 test was used to compare the observed sex ratios of these offspring with the expected sex ratio of 0.514. Maternal and paternal exposure did not affect the sex ratio of the F1 generation overall (Table). In the F2 generation, the sex ratios of offspring born to both exposed mothers (0.470) and exposed fathers (0.489) were less than expected. The daughters of both Yusho fathers and Yusho mothers also had a lower sex ratio in their offspring (0.473 and 0.441 in the F2 generation). When restricting to Yusho parents exposed before 20 years of age, the sex ratios were lower for both exposed fathers (0.465) and exposed mothers (0.450). The sex ratio was lowest for the offspring of daughters of early-exposed Yusho mothers (0.348). These data suggest that a low sex ratio of offspring born to mothers exposed to high dioxin levels may be transmitted to a second generation through the female line. Mothers exposed before 20 years of age showed more pronounced reduction in male births, suggesting that women may be more susceptible to dioxin toxicity. The mechanisms of action underlying sex-ratio alterations are not understood. Sexual differentiation in human being is controlled by genetic and hormonal factors. The ability of an external agent to induce a transgenerational effect would require either a chromosomal alteration or an epigenetic phenomenon, such as DNA methylation or histone modification. Genotoxic effects on the germ line may cause decreased numbers of male offspring through greater susceptibility to genomic errors. Moreover, PCBs and dioxins can be antiestrogenic or antiandrogenic. Environmental toxicants that can directly target the ovary and can also alter epigenetic mechanisms in the oocyte, leading to transgenerational reproductive dysfunction. These effects are mediated primarily by steroid hormone receptors, especially estrogen receptors in the ovary. Thus, epigenetic effects on the female germ line may also affect the sex ratio through effects of maternal hormone levels around the time of conception; high levels of estrogens and androgens have been associated with male offspring. Further studies into Supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Health, Labour and Welfare, Japan (H22-Designated Research-001) and Environment Research and Technology Development Fund of the Ministry of the Environment, Japan (C-0903). The authors reported no other financial interests related to this research. Copyright

FDG PET/CT findings in acquired perforating dermatosis.

Acquired perforating dermatosis (APD) is an uncommon cutaneous perforating disorder. We report a patient on hemodialysis who developed skin eruption and jaundice. He underwent FDG PET/CT under suspicion of biliary malignancies. PET/CT showed no significant abnormal uptake except of multiple FDG-avid nodules in the skin. The eruption he had was histopathologically diagnosed as APD by skin biopsy. His case suggests that APD should be considered as a differential diagnosis when multiple cutaneous FDG accumulations are found in a patient on hemodialysis. To the best of our knowledge, this is the first report showing the FDG PET/CT findings of APD.