Tienilic acid enhances hyperbilirubinemia in Eisai hyperbilirubinuria rats through hepatic multidrug resistance-associated protein 3 and heme oxygenase-1 induction.

We demonstrated that tienilic acid, a diuretic drug withdrawn from the market because of hepatic failure, enhanced hyperbilirubinemia in Eisai hyperbilirubinuria rats (EHBR) with a defect of canalicular multidrug resistance-associated protein 2 (Mrp2). In contrast, no remarkable changes were noted in Sprague-Dawley (SD) rats, the parent strain for EHBR. To investigate a mechanism underlying this enhanced hyperbilirubinemia, we focused on comprehensive effects of tienilic acid on clinicopathological aspects and expression of hepatic transporters. Other than eventual hyperbilirubinemia with slightly increased biliary bilirubin, a single oral treatment of EHBR with tienilic acid at 300 mg/kg caused no changes in serum alanine aminotransferase and alkaline phosphatase, bile flow rate and biliary bile acid secretion, or hepatic morphology. In analyses of mRNA expression of the hepatic transporters, elevated Mrp3 expression in EHBR correlated with an increase in serum total bilirubin, suggesting increased bilirubin transport from the liver into the peripheral blood flow. Hepatic heme oxygenase-1 (Ho-1) mRNA, a stress-induced isoform of the rate-limiting enzyme in the catabolism of heme to bilirubin, was markedly upregulated in EHBR at the same dose at which increased serum bilirubin was seen. A time-course study revealed that marked induction of Ho-1 occurred earlier than that of Mrp3, followed by an increase in serum bilirubin. These results suggest that hepatic Mrp3 and Ho-1 may contribute to tienilic acid-enhanced hyperbilirubinemia in EHBR by inducing increased bilirubin transport from the liver into the blood stream, preceded by potentiation of bilirubin formation in the liver.

Investigation of initial changes in the mouse olfactory epithelium following a single intravenous injection of vincristine sulphate.

To investigate initial changes in the olfactory epithelium, vincristine sulphate (VCR) was administered intravenously once to male BALB/c mice on day 1 in comparison with unilateral bulbectomy (UBT). The light and electron microscopy of the olfactory epithelium, nerve and/or bulb with BrdU-morphometry was performed sequentially. Further, whole-body radioluminography was conducted at 1 and 24 hours postdose. Apoptosis and an increased number of mitotic cells with a tendency toward decreasing BrdU-positive olfactory epithelial cell counts were observed in olfactory epithelial cells at 6 hours postdose of VCR and became more pronounced at 24 hours postdose. These changes disappeared on days 4 or 15, but minimal axonal degeneration was seen in the olfactory nerve from day 4 onward. Semiquantitative measurement of VCR levels in the ethmoturbinals elicited high drug retention even 24 hours after administration. In contrast, UBT showed no effect on mitosis and BrdU-positive cell counts at 6 hours postdose, but severe lesions in the olfactory epithelium and nerve were seen on days 2, 4, and/or 15. The above results suggest that the initial event of VCR-induced apoptosis in the mouse olfactory epithelium would be mitotic arrest with high drug retention, unlike that evoked by UBT.

Inhibitory effect of sulfobutyl ether beta-cyclodextrin on DY-9760e-induced cellular damage: In vitro and in vivo studies.

The effects of water-soluble beta-cyclodextrin derivatives (beta-CyDs), such as 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and sulfobutyl ether beta-cyclodextrin (SBE7-beta-CyD) on cytotoxicity of DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate) toward human umbilical vein endothelial cells (HUVECs) in vitro and vascular damage of the auricular vein of rabbits by DY-9760e in vivo were investigated. The spectroscopic study revealed that of the four beta-CyDs SBE7-beta-CyD forms the most stable inclusion complex in phosphate-buffered saline, probably because of a synergetic effect of hydrophobic and electrostatic interactions. beta-CyDs inhibited DY-9760e-induced cell death toward HUVECs in an order of G(2)-beta-CyD < beta-CyD < HP-beta-CyD < SBE7-beta-CyD, which was consistent with the order of the magnitude of stability constants. When the DY-9760e solution was infused into the auricular vein of rabbits for 24 h, SBE7-beta-CyD suppressed a DY-9760e-induced irritation such as thrombus, desquamation of the endothelium vasculitis, and perivasculitis. The present data indicated that SBE7-beta-CyD formed an inclusion complex with DY-9760e in a buffer solution and possessed the protective effect on DY-9760e-induced cytotoxicity toward HUVECs and vascular damage in rabbits. These results suggested potential use of SBE7-beta-CyD as a parenteral carrier for DY-9760e.