Biphasic elevation of bilirubin oxidation during myocardial ischemia reperfusion.

BACKGROUND: The time course of oxidative stress involving nitric oxide (NO) after myocardial ischemia reperfusion (MIR) has not been elucidated in detail, so the present study was designed to assess the dynamics of oxidative stress after MIR, urinary excretion of oxidized bilirubin metabolites (ie, biopyrrins) and their generation in various organs. METHODS AND RESULTS: Rat models of MIR were created by occluding the left coronary artery for 30 min followed by 48 h of reperfusion. Levels of urinary biopyrrins increased biphasically at 8 h and 24 h after MIR. Biopyrrins were upregulated in the lungs at 8 h after MIR, according to immunohistochemistry and ELISA, and at 24 h biopyrrin expression was increased in the heart and lungs. The NO synthase inhibitor, NG-monomethyl-L-arginine, significantly diminished biopyrrin synthesis in the heart and lungs at 24 h, but not in the lungs at 8 h after MIR. Hemodynamic assessment revealed increased left ventricle end-diastolic pressure, suggesting that lung congestion influences pulmonary biopyrrin formation. CONCLUSIONS: The dynamics of urinary biopyrrins might reflect earlier biopyrrin generation in the lungs and delayed formation in both the lungs and heart when NO is involved. Therefore, urinary biopyrrins can serve as a useful marker of systemic oxidative stress after MIR.

Inhibition of neointimal hyperplasia development by MCI-186 is correlated with downregulation of nuclear factor-kappaB pathway.

BACKGROUND: Atherosclerosis is a progressing inflammatory response mediated by various signaling molecules among which nuclear factor kappaB (NF-kappaB) is thought to have a pivotal role. This study demonstrated the efficacy of antioxidant MCI-186 in preventing the progression of atherosclerosis by inhibiting signaling molecules such as NF-kappaB. METHODS AND RESULTS: Balloon injury of intima was performed in the right common carotid artery of Japanese male white rabbits, which were then fed a 1% high cholesterol diet for 4 weeks, after assigning them to either the control (n=7) or MCI-186 (0.5 mg .kg(-1) . day(-1), n=7) group. Histological analysis revealed a reduction in neointimal thickness and lipid deposition in the subendothelial area of the MCI-186 group. Immunohistochemical analysis revealed attenuation of E-selectin expression, macrophage migration and proliferation of smooth muscle cells in the MCI-186 treated group. In in vitro studies, rabbit aorta smooth muscle cells were incubated with rIL-1betain either the presence or absence of MCI-186. MCI-186 significantly inhibited rIL-1beta-induced proliferation of smooth muscle cells from rabbit aorta, as well as the activation of NF-kappaB. Moreover, western blot analysis showed the inhibitory action of MCI-186 on the nuclear translocation of NF-kappaB in human umbilical vein endothelial cells under rIL-1betastimulation. CONCLUSIONS: MCI-186 could provide a novel therapeutic strategy for atherosclerosis by inhibiting the NF-kappaB pathway.

Supplementation of nucleoside-nucleotide mixture enhances functional recovery and energy metabolism following long-time hypothermic heart preservation.

BACKGROUND: OG-VI, a well-balanced mixture of nucleoside and nucleotides, has been demonstrated to have a favorable effect on energy metabolism. In this study, we tested the hypothesis that addition of OG-VI to the University of Wisconsin solution can improve the cardiac functional recovery following long-time hypothermic preservation. MATERIALS AND METHODS: Forty-two male Wistar rats were randomized into four groups. After 30-min of isolated working heart perfusion, the rat hearts were arrested with St. Thomas cardioplegic solution and preserved at 4 degrees C in saline, OG-VI, UW, and UW+OG-VI, respectively. After 12-h of preservation, the hearts were reperfused for 60-min during which the recovery of cardiac functions were monitored continuously. Myocardial adenine nucleotides were analyzed using high-performance liquid chromomatograph. RESULTS: In the UW+OG-VI group, the recovery of cardiac output, coronary flow, aortic flow, rate-pressure product, left ventricle stroke volume, and stroke work were significantly higher than other groups (P < 0.05). Furthermore, all phosphate high-energy compounds were significantly higher in the UW+OG-VI group than in the other groups (P < 0.05). Coronary vascular resistance and myocardial wet/dry weight ratio were obviously lower in the UW+OG-VI group, compared to the other groups (P < 0.05). CONCLUSIONS: Heart function was better recovered when nucleoside-nucleotide mixture was added to UW solution during long-time hypothermic rat heart preservation. The mechanism is not totally clear, but enhancement of high-energy phosphate production is possible.

MCI-186 inhibits tumor growth through suppression of EGFR phosphorylation and cell cycle arrest.

BACKGROUND: It has been suggested that radicals stimulate tumor cell growth. We examined if the hydroxyl radical scavenger, 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186), affects tumor growth in vitro. MATERIALS AND METHODS: Human hepatocarcinoma HepG2, mesothelioma MSTO-211H, gastric carcinoma TMK-1 and breast carcinoma MCF-7 were used for cell proliferation assay. Cell cycle analysis was performed using propidium iodide for fluorescence activated cell sorter. By Western blotting, EGF receptor (EGFR) phosphorylation and EGFR expression were analyzed. RESULTS: Growth inhibition was observed from 10 microM to 300 microM of MCI-186 in a dose-dependent manner. Cell cycle analysis revealed that MCI-186 arrested the cell cycle at the G0/G1-phase. MCI-186 inhibited EGF-stimulated cell growth. The phosphorylation level of EGFR was decreased by MCI-186, but the EGFR level was unchanged. CONCLUSION: From the data obtained, we suggest that tumor inhibition by MCI-186 was due, at least in part, to the modulation of EGFR signaling and cell cycle arrest.