8OHdG as a marker for Huntington disease progression.
ABSTRACT Leukocyte 8-hydroxydeoxyguanosine (8OHdG) is an indicator of oxidative stress, impaired metabolism, and mitochondrial dysfunction, features that have been implicated in Huntington disease (HD). Increased levels of 8OHdG have been reported in the caudate, parietal cortex, and peripherally in the serum and leukocytes, in patients diagnosed with HD. However, little is known about levels in prodromal patients and changes that might occur as the disease progresses. To address these issues, 8OHdG was tracked over time for a subset of participants enrolled in the PREDICT-HD study. Participants were stratified into four groups based on proximity to HD diagnosis at study entry: Controls (gene-negative individuals), Low (low probability of near-future diagnosis), Medium, and High. Blood samples were analyzed using Liquid Chromatography Electrochemical Array, and for comparison purposes, a separate cross-sectional sample was analyzed using liquid chromatography coupled with multiple-reaction-monitoring mass spectrometry. Longitudinal data analysis showed that initial status (at study entry) and annual rate of change varied as a function of proximity group, adjusting for sex, education, age at study entry, and site effects. Overall levels were lowest for the Control group and highest for the High group, and the rate of increase varied in a similar manner. The finding that 8OHdG concentrations increased as a function of proximity to projected disease diagnosis and duration indicates support for the continued assessment of 8OHdG as a robust clinical HD biomarker.
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ABSTRACT: Huntington's disease (HD) is caused by cytosine-adenine-guanine (CAG) repeat expansions in the huntingtin (Htt) gene. Although early energy metabolic alterations in HD are likely to contribute to later neurodegenerative processes, the cellular and molecular mechanisms responsible for these metabolic alterations are not well characterized. Using the BACHD mice that express the full-length mutant huntingtin (mHtt) protein with 97 glutamine repeats, we first demonstrated localized in vivo changes in brain glucose use reminiscent of what is observed in premanifest HD carriers. Using biochemical, molecular, and functional analyses on different primary cell culture models from BACHD mice, we observed that mHtt does not directly affect metabolic activity in a cell autonomous manner. However, coculture of neurons with astrocytes from wild-type or BACHD mice identified mutant astrocytes as a source of adverse non-cell autonomous effects on neuron energy metabolism possibly by increasing oxidative stress. These results suggest that astrocyte-to-neuron signaling is involved in early energy metabolic alterations in HD.Journal of Cerebral Blood Flow & Metabolism advance online publication, 18 June 2014; doi:10.1038/jcbfm.2014.110.Journal of Cerebral Blood Flow & Metabolism 06/2014; 34(9). · 5.34 Impact Factor
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ABSTRACT: Activation of microglial cells and impaired mitochondrial function are common pathological characteristics of many neurological diseases and contribute to increased generation of reactive oxygen species (ROS). It is nowadays accepted that oxidative damage and mitochondrial dysfunction are key hallmarks of classical neuroinflammatory and neurodegenerative diseases, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease and Huntington's disease. To counteract the detrimental effects of ROS and restore the delicate redox balance in the central nervous system (CNS), cells are equipped with an endogenous antioxidant defense mechanism consisting of several antioxidant enzymes. The production of many antioxidant enzymes is regulated at the transcriptional level by the transcription factor nuclear factor E2-related factor 2 (Nrf2). Although evidence is accumulating that activation of the Nrf2 pathway represents a promising therapeutic approach to restore the CNS redox balance by reducing ROS-mediated neuronal damage in experimental models of neurodegenerative disorders, only a few Nrf2-activating compounds have been tested in a clinical setting. We here provide a comprehensive synopsis on the role of ROS in common neurodegenerative disorders and discuss the therapeutic potential of the Nrf2 pathway.Archive für Toxikologie 08/2014; · 5.08 Impact Factor
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ABSTRACT: Context: Peripheral oxidative biomarkers could be useful for monitoring clinical features of Huntington’s disease (HD). Materials and methods: Cu/Zn-superoxide dismutase (Cu/Zn-SOD), neuron-specific enolase (NSE) and 8-hydroxy-20-deoxyguanosine (8-oxoGua) serum levels were analysed in 18 HD patients and 10 controls. Clinical measures were recorded from each HD patients. Results: Cu/Zn-SOD, NSE and 8-oxoGua values were higher in HD patients than in controls. Cu/Zn-SOD and NSE correlated positively. No correlation was observed between the biomarkers analysed and the clinical measures assessed. Discussion and conclusion: Serum oxidative biomarkers could express the neuronal oxidative processes going on in HD patients but are inadequate to evaluate clinical features of the diseaseBiomarkers 07/2014; · 2.52 Impact Factor