Masaki, Katsunori



School of Medicine, Department of Internal Medicine (Pulmonary Medicine) (Shinanomachi)




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  • Rare presentation of anaphylaxis: Pancake syndrome

    Masaki K., Fukunaga K., Kawakami Y., Haque R.

    BMJ Case Reports (BMJ Case Reports)  12 ( 3 )  2019.03

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    © BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ. A 43-year-old woman presented with oral discomfort, sneezing, urticaria, eyelid angioedema, abdominal pain, diarrhoea, dyspnoea and wheeze soon after eating a Japanese flour pancake (okonomiyaki, containing wheat, egg, yam, pork, prawn and squid). Subsequent analysis of the flour used in the pancake revealed the presence of Dermatophagoides farinae (4500 mites/g). The patient tested positive for specific IgE to D. farinae (15.2 kU/L) and D. pteronyssinus (14.0 kU/L) with negative responses to other ingredients in the pancake. Oral ingestion of dust mite in poorly stored foods can cause anaphylactic reactions in patients with allergy.

  • 12-OH-17,18-Epoxyeicosatetraenoic acid alleviates eosinophilic airway inflammation in murine lungs

    Mochimaru T., Fukunaga K., Miyata J., Matsusaka M., Masaki K., Kabata H., Ueda S., Suzuki Y., Goto T., Urabe D., Inoue M., Isobe Y., Arita M., Betsuyaku T.

    Allergy: European Journal of Allergy and Clinical Immunology (Allergy: European Journal of Allergy and Clinical Immunology)  73 ( 2 ) 369 - 378 2018.02

    ISSN  01054538

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    © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd. Background: Asthma is characterized by airway inflammation and obstruction with eosinophil infiltration into the airway. Arachidonic acid, an omega-6 fatty acid, is metabolized into cysteinyl leukotriene with pro-inflammatory properties for allergic inflammation, whereas the omega-3 fatty acid eicosapentaenoic acid (EPA) and its downstream metabolites are known to have anti-inflammatory effects. In this study, we investigated the mechanism underlying the counter-regulatory roles of EPA in inflamed lungs. Methods: Male C57BL6 mice were sensitized and challenged by ovalbumin (OVA). After EPA treatment, we evaluated the cell count of Bronchoalveolar lavage fluid (BALF), mRNA expressions in the lungs by q-PCR, and the amounts of lipid mediators by liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based lipidomics. We investigated the effect of the metabolite of EPA by in vivo and in vitro studies. Results: Eicosapentaenoic acid treatment reduced the accumulation of eosinophils in the airway and decreased mRNA expression of selected inflammatory mediators in the lung. Lipidomics clarified the metabolomic profile in the lungs. Among EPA-derived metabolites, 12-hydroxy-17,18-epoxyeicosatetraenoic acid (12-OH-17,18-EpETE) was identified as one of the major biosynthesized molecules; the production of this molecule was amplified by EPA administration and allergic inflammation. Intravenous administration of 12-OH-17,18-EpETE attenuated airway eosinophilic inflammation through downregulation of C-C chemokine motif 11 (CCL11) mRNA expression in the lungs. In vitro, this molecule also inhibited the release of CCL11 from human airway epithelial cells stimulated with interleukin-4. Conclusion: These results demonstrated that EPA alleviated airway eosinophilic inflammation through its conversion into bioactive metabolites. Additionally, our results suggest that 12-OH-17,18-EpETE is a potential therapeutic target for the management of asthma.

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