Noninvasively Measured Human Brain Glutathione and Ascorbate Concentrations in Healthy Aging and in Alzheimer's Disease

181 The Role of Denervation in Cytokine-Mediated Muscle Dysfunction in Old Mice Caroline Amy Staunton1, Natalie Pollock1, Rachel McCormick1, Aphrodite Vasilaki1, Richard Barrett-Jolley1, Malcolm Jackson1, and Anne McArdle1 1 Institute of Ageing and Chronic Disease, University of Liverpool, UK Age-related loss of muscle mass and function greatly influences the quality of life of older people. Denervation and increases in proinflammatory cytokines are proposed to play a substantial role in this muscle dysfunction. Full denervation of muscle of adult mice causes an increase in the rate of mitochondrial peroxide production1 and data from our laboratory have further demonstrated that this peroxide generation by muscle remained significantly elevated for up to 10 days after denervation, compared with sham controls. Further data suggest that increased mitochondrial peroxide generation may mediate cytokine production by muscle cells2. We hypothesise that the denervation evident in some muscle fibres of old mice results in increased mitochondrial peroxide generation which in turn results in increased production of cytokines by muscle, further contributing to muscle dysfunction. The aim of this study was (1) to use intra-vital imaging in Thy1-CFP mice to examine the structure of peripheral axons and neuromuscular junctions in single muscle fibers in vivo and to monitor H2O2 generation by denervated muscle fibers using AAV6Hyper2-Cyto injected mice and (2) to examine the effects of increased H2O2 on NF-B activation and the production of proinflammatory cytokines in these fibers. Data demonstrated that the increased mitochondrial peroxide generation in fully denervated muscle of adult mice was associated with activation of NF-B and increased production of proinflammatory cytokines including IL-6, MCP1 and CXCL1. These data suggest that denervation of individual muscle fibers in old mice may result in elevations in H2O2 production in both denervated and innervated fibers and that this may play a role in the increased activation of NF-κB and production of proinflammatory cytokines seen in muscles of old mice. Current work focuses on assessment of neuromuscular transmission using electrophysiology in single fibers to determine which age-related changes in neuromuscular junction structure are associated with a lack of neuromuscular activity and cytokine production. References: Muller FL, et al 2007. Am J. Physiol. (Reg) 293:R1159-1168. Lightfoot AP, et al 2015. Redox biology. 6:253-259, 2015. Supported by the UK MRC and NIA (AG-20591).

doi: 10.1016/j.freeradbiomed.2016.10.222 182 Noninvasively Measured Human Brain Glutathione and Ascorbate Concentrations in Healthy Aging and in Alzheimer's Disease Melissa Terpstra1, J. Riley McCarten2, James Hodges1, Laura S Hemmy2, Andrea Grant1, Dinesh K Deelchand1, and Malgorzata Marjanska1 1 University of Minnesota, Minneapolis, USA, 2Minneapoils VA Health Care System, USA

Numerous studies have found lower levels of antioxidants in the blood and cerebrospinal fluid of elderly adults. Oxidative stress is involved in Alzheimer’s disease (AD) pathogenesis and progression. Increased sensitivity of magnetic resonance technology has made it possible to noninvasively quantify concentrations of the antioxidants glutathione (GSH) and ascorbate (Asc) in intact human brain. Ultra-high field magnetic resonance spectroscopy (MRS) was used to measure concentrations of GSH and ascorbate in the occipital cortex (OCC) and posterior cingulate cortex (PCC) of seventeen young adults, sixteen cognitively normal older adults, and eight patients with AD. The short-echo-time MRS approach inherently retained numerous resonances, from which a profile of 15 neurochemicals was measured. For the first time, the concentration of GSH was found to be lower (p = 0.02) in the OCC of the elderly in a way that is not contingent upon the transverse relaxation rate. Healthy aging tended to impact neurochemicals associated with excitotoxicity (i.e. N-acetylaspartate) in the OCC, whereas those more closely linked to reactive astrogliosis (i.e.,myo-inositol, creatine and choline) were impacted in the PCC. The concentration of Asc was lower (p = 0.005) in the PCC of the patients with AD than in the healthy older adults. This is the first time human brain Asc has been studied noninvasively in patients with AD. In patients, one of the neurochemicals associated with reactive astrogliosis (myo-inositol) was higher in the OCC and two were higher in the PCC (i.e., myoinositol and choline). Taken together, these outcomes show that both aging and AD impact brain regions differentially. These findings fill part of the gap in understanding how the brain deteriorates throughout aging and AD. Ultra-high field ultra-shortecho-time MRS supplies hitherto missing steps along the pathway to preventing and treating cognitive decline, i.e. means to identify which antioxidant is compromised, in which brain region, in whom, and whether intervention can achieve normalization.

doi: 10.1016/j.freeradbiomed.2016.10.223 183 G6PD Overexpression Protects Mice Against Associated Oxidative Stress and Delays the Occurrence of Frailty Jose Vina1, Manuel Serrano2, Sandrina Nóbrega-Pereira3, Pablo J. Fernandez-Marcos2, Thomas Brioche4, Mari Carmen Gomez-Cabrera5, Andrea Salvador-Pascual5, Juana M. Flores6, and Miriam Quintela Diaz5 1 University of Valencia, Spain, 2Tumour Suppression Group, Spanish National Cancer Research Centre (CNIO),Spain, Spain, 3 Instituto de Medicina Molecular, Universidade de Lisboa, Portugal, 4 Université de Montpellier, Dynamique Musculaire et Métabolisme, Montpellier, France, 5Department of Physiology. University of Valencia, Spain, 6Animal Surgery and Medicine Department, Complutense University of Madrid, Spain To assess the impact of lifelong overexpression of G6PD on reactive oxygen species (ROS)-derived damage and the prevention of frailty, we measured the levels of macromolecular oxidative damage in young and old mice and the we tested the neuromuscular fitness and the grip strength in old mice. Old G6PD-Tg male and female mice showed diminished accumulation of DNA oxidation (measured as 8-hydroxyguanosine or 8-OHdG) in liver and brain. Old females also showed reduced lipid oxidation (measured as malondialdehyde or MDA) in the liver. Old G6PD-Tg males, but not females, presented a small but significant increase in brain protein carbonylation. In accordance with these findings, liver from 2-year-old G6PD-Tg female mice presented an elevated reduced versus oxidized gluthatione ratio (GSH:GSSG) ratio, due to an elevation in reduced GSH.Old G6PD-

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