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Febuxostat Improved Systolic Function and Cardiac Fibrosis with Antioxidants Effects in Dilate Cardiomyopathy Hamsters
97 ,PSDLULQJS+*UDGLHQWDQG0HPEUDQH3RWHQWLDO 0HGLDWHV5HGR['\VIXQFWLRQLQWKH0LWRFKRQGULDRI 3RVW,VFKHPLF+HDUW
Patrick T. Kang1, Chwen-Lih Chen1, Paul Lin1, and Yeong-Renn Chen1 1 Northeast Ohio Medical University, USA (OHFWURFKHPLFDOJUDGLHQW ǻS ZKLFKLVFRPSULVHGRIS+JUDGLHQW ǻS+ DQG PHPEUDQH SRWHQWLDO ǻȌ LV FUXFLDO LQ FRQWUROOLQJ mitochondrial energy transduction. During myocardial ischemia and reperfusion (I/R), mitochondrial dysfunction mediates superoxide (O2x) overproduction and redox dysfunction. +RZHYHU WKH UROH RI ǻS+ DQG ǻȌ LQ WKH SRVW-ischemic injury is not fully established. We employed the EPR spin trapping technique to study isolated mitochondria (IR) from the infarct region of rat heart subjected to 30 min of coronary ligation and 24 h of reperfusion in vivo. The mitochondrial preparation (Normal) from myocardium of the non-ischemic region served as the control. In the presence of glutamate, malate and ADP, Normal mitochondria exhibited heightened state 3 oxygen consumption rate (OCR) and reduced O2x production. Oligomycin (increases ǻS+ E\ LQKLELWLQJ $73 V\QWKDVH LQFUHDVHG 22x production in Normal mitochondria (by 185r11%) but not significantly in IR mitochondria, indicating mitochondrial O2x JHQHUDWLRQ LV ǻS+ GHSHQGHQW DQG WKDW WKHUH LV LPSDLUPHQW RI ǻS+ LQ ,5 PLWRFKRQGULD &RQYHUVHO\ QLJHULFLQ GLVVLSDWHV ǻS+ DEROLVKHG Normal mitochondria-mediated O2x generation under state 4 conditions by 87.0r1.2%, and this nigericin quenching effect was less pronounced in IR mitochondria (by 48.4r3.5%). Nigericin also increased mitochondrial OCR, and predisposed Normal mitochondria to a more oxidized redox status (by EPR-CMH spin probe). IR mitochondria, although more oxidized than Normal mitochondria, were not responsive to nigericin-induced CMH R[LGDWLRQZKLFKIXUWKHUFRUURERUDWHGRXUREVHUYDWLRQWKDWWKHǻS+ was impaired in IR mitochondria. Valinomycin, a K+ ionophore XVHGWRGLVVLSDWHǻȌGLPLQLVKHG1$'+-linked O2x generation of Normal and IR by 66.3r4.7% and 24.5r4.7%, respectively under VWDWHFRQGLWLRQVLQGLFDWLQJǻȌDOVRFRQWULEXWHGWRPLWRFKRQGULDO O2x JHQHUDWLRQDQG,5PHGLDWHGǻȌLPSDLUPHQW+RZHYHUWKHUH was no significant difference in valinomycin-induced CMH oxidation in Normal and IR mitochondria. In conclusion, we SURSRVHWKHSURWRQEDFNSUHVVXUHLPSRVHGE\PLWRFKRQGULDOǻS+ can restrict electron flow and results in a more reduced P\RFDUGLXP ,5 FDXVHV ǻS+ LPSDLUPHQW DQG SURPSWV D PRUH oxidized myocardium.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.137 98 )HEX[RVWDW,PSURYHG6\VWROLF)XQFWLRQDQG&DUGLDF )LEURVLVZLWK$QWLR[LGDQWV(IIHFWVLQ'LODWH &DUGLRP\RSDWK\+DPVWHUV
Toyokazu Kimura1, Atsushi Sato1, Takayuki Namba1, Shunpei Horii1, Hirotaka Yada1, Takehiko Kujiraoka1, Miki Shimizu2, and Takeshi Adachi1 1 National Defense Medical College, Japan, 2Tokyo University of Agriculture & Technology, Japan Xanthine oxidase (XO) has been implicated in a pivotal role on the pathogenesis and progression of chronic heart failure. The present study was undertaken to demonstrate the increased plasma and cardiac uric acid levels in dilated cardiomyopathic
(DCM) hamsters. We also evaluated the antioxidant effect of oral administration with febuxostat on cardiac function and fibrosis in DCM hamsters. The hamsters were assigned to four groups: non-DCM Control (n=7), DCM-placebo group (n=6), DCM-allopurinol group (30 mg/kg/day, n=6), and the DCM-febuxostat group (10 mg/kg/day, n=7). Drug administrations were initiated at the age of 14 weeks and continued for 8 weeks. Echocardiography was performed at 14 and 22 weeks of age. The serum and heart were obtained for biochemical and histological studies at the end of study. Decreased systolic function in DCM hamsters was shown by echocardiography. Serum and cardiac uric acid, cardiac tissue malondialdehyde, and cardiac fibrosis were increased in DCM compared to those in non-DCM. Treatment with febuxostat preserved systolic function of hearts, and decreased the interstitial fibrosis and cardiac malondialdehyde levels compared to DCM-Placebo group. Allopurinol decreased fibrosis less than feburostat, and did not preserve systolic function and malondialdehyde. This result suggests that febuxostat but not alloprinol has potential as a novel therapeutic strategy for treating DCM with suppression of oxidative stress.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.138 99 'HK\GURDVFRUEDWH,QGXFHG3HSWLGH6 *OXWDWKLRQ\ODWLRQDQG6+RPRF\VWHLQ\ODWLRQ
Jordan Deslandes1, Jessy-Carol Ntunzwenimana1, Laurane Forestier2, Vincent Lacasse1, Richard J Wagner1, and Klaus Klarskov1 1 Université de Sherbrooke, Canada, 2ENSIACET, France Vitamin C (AA, ascorbic acid; ascorbate ion at physiological pH) is a well-known protectant of organisms. In this process, ascorbate is oxidized by the loss of one electron to give initially an ascorbyl free radical (SDA), which subsequently undergoes oxidation to dehydroascorbate (DHA). Under physiological conditions, both SDA and DHA are recycled back to ascorbate through the action of several enzymes including NADH-cytochrome b5 reductase, thioredoxin reductase, protein disulfide isomerase, glutaredoxin-1 (thioltransferase), and certain glutathione-S-transferases. Like AA, glutathione plays a crucial role in maintaining the redox homeostasis of cells by among other being implicated in the recycling of AA and scavenging of radicals. In the recycling of AA, glutathione is oxidised to glutathione dimer, which is likely to induce protein S-glutathionylation. In the present study we investigated by mass spectrometry DHA-induced glutathionylation of a small cysteine containing heptapeptide (Ac-FHAACAK) and demonstrate that S-glutathionylation increases as a function of DHA concentration and incubation time. In the presence of DHA, heptapeptide and glutathione dimerization increased in a similar manner. Homocysteine is a non-protein amino acid, differing from cysteine by containing an additional methylene bridge. A high blood level of homocysteine (Hcy) is a recognized risk factor for several major oxidative stress related pathologies such as cardiovascular diseases and neurological diseases. Since Hcy efficiently reduces DHA to AA, we investigated if in this process DHA also induced peptide S-homocysteinylation. Similar to the reaction with GSH, S-homocysteinylation increased as a function of time demonstrating a possible direct link between DHA and homocysteine. The biological importance of these modifications remains to be elucidated.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.139
SFRBM 2015
S53
Patrick T. Kang1, Chwen-Lih Chen1, Paul Lin1, and Yeong-Renn Chen1 1 Northeast Ohio Medical University, USA (OHFWURFKHPLFDOJUDGLHQW ǻS ZKLFKLVFRPSULVHGRIS+JUDGLHQW ǻS+ DQG PHPEUDQH SRWHQWLDO ǻȌ LV FUXFLDO LQ FRQWUROOLQJ mitochondrial energy transduction. During myocardial ischemia and reperfusion (I/R), mitochondrial dysfunction mediates superoxide (O2x) overproduction and redox dysfunction. +RZHYHU WKH UROH RI ǻS+ DQG ǻȌ LQ WKH SRVW-ischemic injury is not fully established. We employed the EPR spin trapping technique to study isolated mitochondria (IR) from the infarct region of rat heart subjected to 30 min of coronary ligation and 24 h of reperfusion in vivo. The mitochondrial preparation (Normal) from myocardium of the non-ischemic region served as the control. In the presence of glutamate, malate and ADP, Normal mitochondria exhibited heightened state 3 oxygen consumption rate (OCR) and reduced O2x production. Oligomycin (increases ǻS+ E\ LQKLELWLQJ $73 V\QWKDVH LQFUHDVHG 22x production in Normal mitochondria (by 185r11%) but not significantly in IR mitochondria, indicating mitochondrial O2x JHQHUDWLRQ LV ǻS+ GHSHQGHQW DQG WKDW WKHUH LV LPSDLUPHQW RI ǻS+ LQ ,5 PLWRFKRQGULD &RQYHUVHO\ QLJHULFLQ GLVVLSDWHV ǻS+ DEROLVKHG Normal mitochondria-mediated O2x generation under state 4 conditions by 87.0r1.2%, and this nigericin quenching effect was less pronounced in IR mitochondria (by 48.4r3.5%). Nigericin also increased mitochondrial OCR, and predisposed Normal mitochondria to a more oxidized redox status (by EPR-CMH spin probe). IR mitochondria, although more oxidized than Normal mitochondria, were not responsive to nigericin-induced CMH R[LGDWLRQZKLFKIXUWKHUFRUURERUDWHGRXUREVHUYDWLRQWKDWWKHǻS+ was impaired in IR mitochondria. Valinomycin, a K+ ionophore XVHGWRGLVVLSDWHǻȌGLPLQLVKHG1$'+-linked O2x generation of Normal and IR by 66.3r4.7% and 24.5r4.7%, respectively under VWDWHFRQGLWLRQVLQGLFDWLQJǻȌDOVRFRQWULEXWHGWRPLWRFKRQGULDO O2x JHQHUDWLRQDQG,5PHGLDWHGǻȌLPSDLUPHQW+RZHYHUWKHUH was no significant difference in valinomycin-induced CMH oxidation in Normal and IR mitochondria. In conclusion, we SURSRVHWKHSURWRQEDFNSUHVVXUHLPSRVHGE\PLWRFKRQGULDOǻS+ can restrict electron flow and results in a more reduced P\RFDUGLXP ,5 FDXVHV ǻS+ LPSDLUPHQW DQG SURPSWV D PRUH oxidized myocardium.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.137 98 )HEX[RVWDW,PSURYHG6\VWROLF)XQFWLRQDQG&DUGLDF )LEURVLVZLWK$QWLR[LGDQWV(IIHFWVLQ'LODWH &DUGLRP\RSDWK\+DPVWHUV
Toyokazu Kimura1, Atsushi Sato1, Takayuki Namba1, Shunpei Horii1, Hirotaka Yada1, Takehiko Kujiraoka1, Miki Shimizu2, and Takeshi Adachi1 1 National Defense Medical College, Japan, 2Tokyo University of Agriculture & Technology, Japan Xanthine oxidase (XO) has been implicated in a pivotal role on the pathogenesis and progression of chronic heart failure. The present study was undertaken to demonstrate the increased plasma and cardiac uric acid levels in dilated cardiomyopathic
(DCM) hamsters. We also evaluated the antioxidant effect of oral administration with febuxostat on cardiac function and fibrosis in DCM hamsters. The hamsters were assigned to four groups: non-DCM Control (n=7), DCM-placebo group (n=6), DCM-allopurinol group (30 mg/kg/day, n=6), and the DCM-febuxostat group (10 mg/kg/day, n=7). Drug administrations were initiated at the age of 14 weeks and continued for 8 weeks. Echocardiography was performed at 14 and 22 weeks of age. The serum and heart were obtained for biochemical and histological studies at the end of study. Decreased systolic function in DCM hamsters was shown by echocardiography. Serum and cardiac uric acid, cardiac tissue malondialdehyde, and cardiac fibrosis were increased in DCM compared to those in non-DCM. Treatment with febuxostat preserved systolic function of hearts, and decreased the interstitial fibrosis and cardiac malondialdehyde levels compared to DCM-Placebo group. Allopurinol decreased fibrosis less than feburostat, and did not preserve systolic function and malondialdehyde. This result suggests that febuxostat but not alloprinol has potential as a novel therapeutic strategy for treating DCM with suppression of oxidative stress.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.138 99 'HK\GURDVFRUEDWH,QGXFHG3HSWLGH6 *OXWDWKLRQ\ODWLRQDQG6+RPRF\VWHLQ\ODWLRQ
Jordan Deslandes1, Jessy-Carol Ntunzwenimana1, Laurane Forestier2, Vincent Lacasse1, Richard J Wagner1, and Klaus Klarskov1 1 Université de Sherbrooke, Canada, 2ENSIACET, France Vitamin C (AA, ascorbic acid; ascorbate ion at physiological pH) is a well-known protectant of organisms. In this process, ascorbate is oxidized by the loss of one electron to give initially an ascorbyl free radical (SDA), which subsequently undergoes oxidation to dehydroascorbate (DHA). Under physiological conditions, both SDA and DHA are recycled back to ascorbate through the action of several enzymes including NADH-cytochrome b5 reductase, thioredoxin reductase, protein disulfide isomerase, glutaredoxin-1 (thioltransferase), and certain glutathione-S-transferases. Like AA, glutathione plays a crucial role in maintaining the redox homeostasis of cells by among other being implicated in the recycling of AA and scavenging of radicals. In the recycling of AA, glutathione is oxidised to glutathione dimer, which is likely to induce protein S-glutathionylation. In the present study we investigated by mass spectrometry DHA-induced glutathionylation of a small cysteine containing heptapeptide (Ac-FHAACAK) and demonstrate that S-glutathionylation increases as a function of DHA concentration and incubation time. In the presence of DHA, heptapeptide and glutathione dimerization increased in a similar manner. Homocysteine is a non-protein amino acid, differing from cysteine by containing an additional methylene bridge. A high blood level of homocysteine (Hcy) is a recognized risk factor for several major oxidative stress related pathologies such as cardiovascular diseases and neurological diseases. Since Hcy efficiently reduces DHA to AA, we investigated if in this process DHA also induced peptide S-homocysteinylation. Similar to the reaction with GSH, S-homocysteinylation increased as a function of time demonstrating a possible direct link between DHA and homocysteine. The biological importance of these modifications remains to be elucidated.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.139
SFRBM 2015
S53