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Development of a Reactive Oxygen Species-Sensitive Nitric Oxide Synthase Inhibitor for the Treatment of Ischemic Stroke

Nash, Kevin Michael
http://orcid.org/0000-0002-1432-890X
http://rave.ohiolink.edu/etdc/view?acc_num=mco1512053682446096

Abstract Details

2017, Doctor of Philosophy (PhD), University of Toledo, Experimental Therapeutics.
Ischemic stroke is caused by a blockage of the blood flow to the brain resulting in neuronal and glial hypoxia leading to inflammatory and free radical-mediated cell death. Reactive oxygen species (ROS) formed in excess under hypoxic conditions cause protein, DNA and lipid oxidation. Nitric oxide (NO) formed by NO synthase (NOS) is known to be protective in ischemic stroke, however NOS has been shown to `uncouple’ under oxidative conditions to instead produce superoxide. Nitrones are antioxidant molecules that are shown to trap ROS to then decompose and release NO. In this study, the PBN-type nitrone 5 was designed such that its decomposition product is a NOS inhibitor, effectively leading to NOS inhibition specifically at the site of ROS production. The ability of 5 to spin-trap radicals and decompose into the putative NOS inhibitor was observed using EPR and LC-MS/MS. The pro-drug concept was tested in vitro by measuring cell viability and inhibitor formation in SH-SY5Y cells subjected to oxygen glucose deprivation (OGD). 5 was found to be more efficacious and more potent than PBN, and was able to increase pAkt while reducing nitrotyrosine and cleaved caspase-3 levels. Doppler flowmetry on anesthetized mice showed an increased cerebral blood flow upon intravenous administration of 1 mg/kg 5, but a return to baseline upon administration of 10 mg/kg, likely due to its dual nature of antioxidant/NO-donor and NOS-inhibition properties. Mice treated with 5 after permanent middle cerebral artery occlusion (pMCAO) performed better in neurobehavioral assessments and exhibited a > 30% reduction in infarct volume. This efficacy is proposed to be due to higher formation of the NOS inhibitor decomposition product in ischemic tissue observed by LC-MS/MS, resulting in region specific effects limited to the infarct area.
Zahoor Shah, Ph.D. (Committee Chair)
Isaac Schiefer, Ph.D. (Committee Member)
F. Scott Hall, Ph.D. (Committee Member)
Wissam AbouAlaiwi, Ph.D. (Committee Member)
138 p.
Biochemistry; Neurobiology; Neurosciences; Organic Chemistry; Pharmacology; Physical Chemistry
Nitrone; Reactive Oxygen Species; Nitric Oxide; Nitric Oxide Synthase; Stroke; Ischemia

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Citations

  • Nash, K. M. (2017). Development of a Reactive Oxygen Species-Sensitive Nitric Oxide Synthase Inhibitor for the Treatment of Ischemic Stroke [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=mco1512053682446096

    APA Style (7th edition)

  • Nash, Kevin. Development of a Reactive Oxygen Species-Sensitive Nitric Oxide Synthase Inhibitor for the Treatment of Ischemic Stroke. 2017. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=mco1512053682446096.

    MLA Style (8th edition)

  • Nash, Kevin. "Development of a Reactive Oxygen Species-Sensitive Nitric Oxide Synthase Inhibitor for the Treatment of Ischemic Stroke." Doctoral dissertation, University of Toledo, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=mco1512053682446096

    Chicago Manual of Style (17th edition)

mco1512053682446096
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© 2017, all rights reserved.
This open access ETD is published by University of Toledo Health Science Campus and OhioLINK.