Maiko Imuta

Kyushu University, Hukuoka, Fukuoka, Japan

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Publications (4)13.83 Total impact

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    ABSTRACT: Epirubicin, an anthracycline antitumor drug, often causes vascular injury such as vascular pain, phlebitis, and necrotizing vasculitis. However, an effective prevention for the epirubicin-induced vascular injury has not been established. The purpose of this study is to identify the mechanisms of cell injury induced by epirubicin in porcine aorta endothelial cells (PAECs). PAECs were exposed to epirubicin for 10 min followed by further incubation without epirubicin. The exposure to epirubicin (3-30 μM) decreased the cell viability concentration and time dependently. Epirubicin increased the activity of caspase-3/7, apoptotic cells, and intracellular lipid peroxide levels, and also induced depolarization of mitochondrial membranes. These intracellular events were reversed by glutathione (GSH) and N-acetylcysteine (NAC), while epirubicin rather increased intracellular GSH slightly and L-buthionine-(S,R)-sulfoximine, a specific inhibitor of GSH synthesis, had no effect on the epirubicin-induced cell injury. The epirubicin-induced cell injury and increase of caspase-3/7 activity were also attenuated by p38 mitogen-activated protein kinase (MAPK) inhibitors, SB203580 and PD169316. Moreover, epirubicin significantly enhanced the phosphorylation of p38 MAPK, and these effects were attenuated by GSH and NAC. In contrast, a c-Jun N-terminal kinase inhibitor SP600125, an extracellular signal-regulated kinase inhibitor PD98059, and a p53 inhibitor pifithrin α did not affect the epirubicin-induced cell injury and increase of caspase-3/7 activity. These results indicate that an activation of p38 MAPK by oxidative stress is involved in the epirubicin-induced endothelial cell injury.
    No preview · Article · Feb 2012 · Free Radical Biology and Medicine
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    ABSTRACT: Nicardipine hydrochloride injection, a dihydropyridine calcium channel blocker, is an acidic drug. The package insert recommends that nicardipine injection should be administered at the concentrations of 0.01-0.02%. However, the drug often induces venous irritation despite infusion at the recommended concentrations in the intensive care unit (ICU) at Kyushu University Hospital. Therefore, we retrospectively investigated the incidence and risk factors of venous irritation in ICU patients. Univariate and multivariate analyses revealed that the administration time and infusion rate of the drug were significantly related to venous irritation (P<0.05). Patients who were infused with nicardipine injection (administration time: more than 24 h, infusion rate: more than 45 mL/h) developed the venous irritation frequently (7 of 9, 77.8%). In the case of infusion of nicardipine injection for more than 96 h, the patients experience severe vascular damage and needed for treatment with medicine such as topical steroids. These results suggest that the administration time and infusion rate are involved in nicardipine injection-induced venous irritation, and it is necessary to pay attention to these factors as well as observing the instructions in the package insert.
    No preview · Article · Jan 2012
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    ABSTRACT: Anticancer drugs are classified as vesicant, irritant, and nonvesicant drugs on the basis of frequency of their vascular disorder. In this study, we compared the injuring effects of three typical anticancer drugs of each class on porcine aorta endothelial cells (PAECs). The concentration inducing 50% cell viability inhibition was lower in the order of vesicant, irritant, and nonvesicant drugs. These results suggest that injuring effects of anticancer drugs on PAECs may be relevant as an indicator of frequency of their vascular disorder, and that this experimental model may be useful for the study of vascular disorder.
    No preview · Article · Sep 2011 · Journal of Pharmacological Sciences
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    ABSTRACT: Vinorelbine (VNR), a vinca alkaloid anticancer drug, often causes vascular injury such as venous irritation, vascular pain, phlebitis, and necrotizing vasculitis. The purpose of this study was to identify the mechanisms that mediate the cell injury induced by VNR in porcine aorta endothelial cells (PAECs). PAECs were exposed to VNR for 10 min followed by further incubation in serum-free medium without VNR. The exposure to VNR (0.3-30 microM) decreased the cell viability concentration and time dependently. The incidence of apoptotic cells significantly increased at 12 h after transient exposure to VNR. At the same time, VNR increased the activity of caspases. Interestingly, VNR rapidly depleted intracellular glutathione (GSH) and increased intracellular reactive oxygen species (ROS) production. Moreover, VNR depolarized the mitochondrial membrane potential and decreased cellular ATP levels. These VNR-induced cell abnormalities were almost completely inhibited by GSH and N-acetylcysteine. On the other hand, L-buthionine-(S,R)-sulfoximine, a specific inhibitor of GSH synthesis, aggravated the VNR-induced loss of cell viability. These results clearly demonstrate that VNR induces oxidative stress by depleting intracellular GSH and increasing ROS production in PAECs, and oxidative stress plays an important role in the VNR-induced cell injury.
    No preview · Article · Oct 2009 · Free Radical Biology and Medicine