3 results on '"Sendo T"'
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2. A prostacyclin analog beraprost sodium attenuates radiocontrast media-induced LLC-PK1 cells injury.
- Author
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Yano T, Itoh Y, Kubota T, Sendo T, and Oishi R
- Subjects
- Animals, Apoptosis drug effects, Base Sequence, Caspases metabolism, Cyclic AMP Response Element-Binding Protein metabolism, Enzyme Activation drug effects, Gene Expression drug effects, Genes, bcl-2, Kidney Tubules metabolism, Kidney Tubules pathology, LLC-PK1 Cells, Phosphorylation, Proto-Oncogene Proteins c-bcl-2 genetics, RNA, Messenger genetics, RNA, Messenger metabolism, Swine, Triiodobenzoic Acids toxicity, bcl-2-Associated X Protein, Contrast Media toxicity, Epoprostenol analogs & derivatives, Epoprostenol pharmacology, Kidney Tubules drug effects
- Abstract
Background: We previously reported that the apoptotic injury in a porcine renal tubular cell line LLC-PK1 cells induced by radiographic contrast media is attenuated by dibutyl cyclic adenosine monophosphate (cAMP) in a manner dependent on protein kinase A (PKA). The present study was designed to determine whether the elevation of endogenous cAMP with beraprost sodium, a prostacyclin analog, reduces the contrast material-induced renal tubular injury., Methods: The cell injury was induced by the exposure to ioversol for 30 minutes followed by further incubation for 24 hours in the absence of the contrast medium, and assessed by propidium iodide uptake and WST-8 assay. Apoptosis was determined by annexin V stain and DNA electrophoresis. Caspase activity was assessed by the enzymatic degradation of specific substrate peptides. Bax and bcl-2 mRNA expression were determined by reverse transcription-polymerase chain reaction (RT-PCR). The phosphorylation of cAMP-responsive element binding protein (CREB) was measured by an immunofluorescent method., Results: Beraprost sodium (10 to 1000 nmol/L) attenuated concentration dependently the ioversol-induced decrease in cell viability, in which the protective effect of beraprost sodium was dependent on the elevation of cellular cAMP content. The phosphorylation of CREB was enhanced by beraprost sodium in PKA-dependent manner. In addition, beraprost sodium reversed the ioversol-induced increase in bax mRNA with a concomitant decrease in bcl-2 mRNA and subsequent activation of caspase-3 and -9, thereby resulting in the inhibition of the nuclear damage., Conclusion: Beraprost sodium reversed the contrast media-induced renal tubular cells in culture by activating cAMP/protein kinase A-dependent phosphorylation of CREB and subsequent enhancement of bcl-2 expression.
- Published
- 2004
- Full Text
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3. Cyclic AMP reverses radiocontrast media-induced apoptosis in LLC-PK1 cells by activating A kinase/PI3 kinase.
- Author
-
Yano T, Itoh Y, Sendo T, Kubota T, and Oishi R
- Subjects
- Animals, Bucladesine pharmacology, Caspases metabolism, Cell Survival drug effects, Enzyme Activation, Kidney Tubules, Proximal cytology, Kidney Tubules, Proximal drug effects, Kidney Tubules, Proximal physiology, LLC-PK1 Cells drug effects, LLC-PK1 Cells enzymology, Osmolar Concentration, Proto-Oncogene Proteins genetics, Proto-Oncogene Proteins c-bcl-2 genetics, RNA, Messenger metabolism, Swine, Time Factors, Triiodobenzoic Acids antagonists & inhibitors, Triiodobenzoic Acids pharmacology, bcl-2-Associated X Protein, Apoptosis drug effects, Contrast Media pharmacology, Cyclic AMP pharmacology, Cyclic AMP-Dependent Protein Kinases metabolism, Iodine Radioisotopes pharmacology, LLC-PK1 Cells physiology, Phosphatidylinositol 3-Kinases metabolism
- Abstract
Background: Radiographic contrast material is one of agents that are prone to cause nephropathy, although little is known about cellular mechanisms underlying contrast media-induced renal failure. The present study was designed to determine the role of caspase in contrast media-induced renal injury. The modulation by cyclic adenosine monophosphate (cAMP) of cell injury was subsequently examined., Methods: LLC-PK1 cells (a proximal renal tubular cell line of porcine origin) were exposed to diverse contrast media for 30 minutes followed by incubation for 24 hours in normal medium. Cell viability was assessed by mitochondrial enzyme activity and propidium iodide stain. Apoptosis was determined by DNA electrophoresis and annexin V stain. Caspase activity was measured fluorometrically. The mRNA for bax and bcl-2 was determined by reverse transcription-polymerase chain reaction (RT-PCR)., Results: Iodinated and magnetic resonance contrast media reduced cell viability due to apoptosis. The cell damage induced by a non-ionic contrast medium ioversol was inhibited by specific inhibitors for caspase-3 and -9 but not caspase-8. Ioversol enhanced the activities of caspase-3 and -9, but to a lesser extent, caspase-8. The bax mRNA was enhanced, while bcl-2 mRNA was reduced, after exposure to ioversol. All of these actions of ioversol were reversed by dibutyl cAMP in the manner sensitive to a protein kinase A inhibitor H89 and a phosphatidylinositol 3 (PI3) kinase inhibitor wortmannin., Conclusion: We demonstrated for the first time that cAMP reversed caspase-dependent apoptotic renal cell damage caused by contrast media. Both protein kinase A and PI3 kinase might be involved in protective effect of cAMP.
- Published
- 2003
- Full Text
- View/download PDF
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