title: Regional Heterogeneity of Cerebral Microvessels and Brain Susceptibility to Oxidative Stress.
abstract: The hippocampus is one of the earliest and most affected regions in Alzheimer's disease (AD), followed by the cortex while the cerebellum is largely spared. Importantly, endothelial dysfunction is a common feature of cerebral blood vessels in AD. In this study, we sought to determine if regional heterogeneity of cerebral microvessels might help explain the susceptibility of the hippocampus and cortex as compared to the cerebellum. We isolated microvessels from wild type mice from the cerebellum, cortex, and hippocampus to characterize their vascular phenotype. Superoxide anion was significantly higher in microvessels isolated from the cortex and hippocampus as compared to the cerebellum. Importantly, protein levels of NADPH oxidase (NOX)-2 and NOX-4 were significantly higher in the cortical and hippocampal microvessels as compared to microvessels from the cerebellum. In addition, expression of manganese superoxide dismutase protein was significantly lower in microvessels from the cortex and hippocampus as compared to cerebellum while other antioxidant enzymes were unchanged. There was no difference in eNOS protein expression between the microvessels of the three brain regions; however, bioavailability of tetrahydrobiopterin (BH4), an essential cofactor for eNOS activity, was significantly reduced in microvessels from the hippocampus and cortex as compared to the cerebellum. Higher levels of superoxide and reduced tetrahydrobiopterin bioavailability may help explain the vulnerability of the hippocampus and cortical microvessels to oxidative stress and development of endothelial dysfunction.
authors.affiliation: Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Austin
authors.affiliation: Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America.
authors.forename: Anantha Vijay R
authors.initials: AV
authors.lastname: Santhanam
authors.affiliation: Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America.
authors.forename: Livius V
authors.initials: LV
authors.lastname: d'Uscio
authors.affiliation: Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America.
authors.forename: Zvonimir S
authors.initials: ZS
authors.lastname: Katusic
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001682:Biological Availability; D001708:Biopterins / Q000031:analogs & derivatives / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism / Q000473:pathology*; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology*; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D055806:Microvessels / Q000378:metabolism / Q000473:pathology*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D013481:Superoxides; D001708:Biopterins; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D013482:Superoxide Dismutase; C003402:sapropterin