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Postmortem Degradation of N-Acetyl Aspartate and N-Acetyl Aspartylglutamate: An HPLC Analysis of Different Rat CNS Regions

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Abstract

N-acetyl aspartate (NAA), a putative marker of neuronal injury, can be measured non-invasively in patients by magnetic resonance spectroscopy (MRS). Interpretation of in vivo MRS data, however, requires neuropathological correlates to NAA alterations using autopsy or biopsy material. Since detailed hydrolysis data is lacking, NAA and the related dipeptide N-acetyl aspartylglutamate (NAAG) were quantified by high performance liquid chromatography (HPLC) in different rat CNS regions over 24 h postmortem. Both molecules decreased rapidly 1-4 h postmortem, and subsequently slower with time. The average reduction at 24 h was 46% and 38% for NAA and NAAG respectively. The NAA reduction was proportionally smaller in cortical areas (34-37%) compared to more caudal regions (54-58%). An exception was the optic nerve, a pure white matter tract, where NAA and NAAG hydrolysis was slower. The NAA/NAAG ratio remained relatively constant, but exhibited marked regional differences. The data show a significant postmortem degradation of NAA and NAAG that needs to be considered when these compounds are studied ex-vivo.

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REFERENCES

  1. Moffett, J. R., Namboodiri, M. A. A., Cangro, C. B., and Neale, J. H. 1991. Immunohistochemical localization of N-acetylaspartate in rat brain. NeuroReport 2:131–134.

    Google Scholar 

  2. Simmons, M. L., Frondoza, C. G., and Coyle, J. T. 1991. Immunocytochemical localization of N-acetyl-aspartate with monoclonal antibodies. Neurosci. 45:37–45.

    Google Scholar 

  3. Clark, J. B. 1998. N-Acetyl Aspartate: A marker for neuronal loss or mitochondrial dysfunction. Dev. Neurosci. 20:271–276.

    Google Scholar 

  4. Urenjak, J., Williams, S. R., Gadian, D. G., and Noble, M. 1992. Specific expression of N-acetylaspartate in neurons, oligodendrocyte-type-2 astrocyte progenitors, and immature oligodendrocytes in vitro. J. Neurochem. 59:55–61.

    Google Scholar 

  5. Bhakoo, K. K. and Pearce, D. 2000. In vitro expression of N-acetyl aspartate by oligodendrocytes: Implications for proton magnetic resonance spectroscopy signal in vivo. J. Neurochem. 74:254–262.

    Google Scholar 

  6. Patel, T. B. and Clark, J. B. 1979. Synthesis of N-acetyl-Laspartate by rat brain mitochondria and involvement in mitochondrial/cytosolic carbon transport. Biochem. J. 184:539–546.

    Google Scholar 

  7. Truckenmiller, M. E., Namboodiri, M. A. A., Brownstein, M. J., and Neale, J. H. 1985. N-acetylation of L-aspartate in the nervous system: Differential distribution of a specific enzyme. J. Neurochem. 45:1658–1662.

    Google Scholar 

  8. Matthews, P. M., De Stefano, N., Narayanan, S., Francis, G. S., Wolinsky, J. S., Antel, J. P., and Arnold, D. L. 1998. Putting magnetic resonance spectroscopy studies in context: Axonal damage and disability in multiple sclerosis. Semin. Neurol. 18:327–336.

    Google Scholar 

  9. Graham, G. D., Blamire, A. M., Howseman, A. M., Rothman, D. L., Fayad, P. B., Brass, L. M., Petroff, O. A., Shulman, R. G., and Prichard, J. W. 1992. Proton magnetic resonance spectroscopy of cerebral lactate and other metabolites in stroke patients. Stroke 23:333–340.

    Google Scholar 

  10. Pioro, E. P., Antel, J. P., Cashman, N. R., and Arnold, D. L. 1994. Detection of cortical neuron loss in motor neuron disease by proton magnetic resonance spectroscopic imaging in vivo. Neurology 44:1933–1938.

    Google Scholar 

  11. Callicott, J. H., Bertolino, A., Egan, M. F., Mattay, V. S., Langheim, F. J. P., Weinberger, B. S., and Weinberger, D. R. 2000. Selective relationship between prefrontal N-acetylaspartate measures and negative symptoms in schizophrenia. Am. J. Psychiatry 157:1646–1651.

    Google Scholar 

  12. De Stefano, N., Matthews, P. M., and Arnold, D. L. 1995. Reversible decreases in N-acetylaspartate after acute brain injury. Magn. Reson. Med. 34:721–727.

    Google Scholar 

  13. Lee, M. A., Blamire, A. M., Pendlebury, S., Ho, K. H., Mills, K. R., Styles, P., Palace, J., and Matthews, P. M. 2000. Axonal injury or loss in the internal capsule and motor impairment in multiple sclerosis. Arch. Neurol. 57:65–70.

    Google Scholar 

  14. Gonen, O., Catalaa, I., Babb, J. S., Ge, Y., Mannon, L. J., Kolson, D. L., and Grossman, R. I. 2000. Total brain N-acetylaspartate a new measure of disease load in MS. Neurology 54:15–19.

    Google Scholar 

  15. Pendlebury, S. T., Lee, M. A., Blamire, A. M., Styles, P., and Matthews, P. M. 2000. Correlating magnetic resonance imaging markers of axonal injury and demyelinaton in motor impairment secondary to stroke and multiple sclerosis. Mag. Reson. Imaging 18:369–378.

    Google Scholar 

  16. Bjartmar, C., Kidd, G., Mörk, S., Rudick, R., and Trapp, B. D. 2000. Neurological disability correlates with spinal cord axonal loss and reduced N-acetyl aspartate in chronic multiple sclerosis patients. Ann. Neurol. 48:893–901.

    Google Scholar 

  17. Lu, F., Selak, M., O'Connor, J., Croul, S., Lorenzana, C., Butunoi, C., and Kalman, B. 2000. Oxidative damage to mitochondrial DNA and activity of mitochondrial enzymes in chronic active lesions of multiple sclerosis. J. Neurol. Sci. 177:95–103.

    Google Scholar 

  18. Rango, M., Spagnoli, D., Tomei, G., Fabrizia, B., Scarlato, G., and Zetta, L. 1995. Central Nervous System trans-synaptic effects of acute axonal injury: A 1H magnetic resonance spectroscopy study. Magn. Reson. Med. 33:595–600.

    Google Scholar 

  19. Baslow, M. H. 2000. Functions of N-acetyl-L-aspartate and N-acetyl-L-aspartylglutamate in the vertebrate brain: Role in glial cell-specific signaling. J. Neurochem. 75:453–459.

    Google Scholar 

  20. Neale, J. H., Bzdega, T., and Wroblewska, B. 2000. N-acetylaspartylglutamate: The most abundant peptide neurotransmitter in the mammalian central nervous system. J. Neurochem. 75:443–452.

    Google Scholar 

  21. Zilles, K. and Wree, A. 1995. Cortex: Areal and laminar structure. Pages 650–651, in Paxinos, G. (ed.), The Rat Nervous System. Academic Press, San Diego.

    Google Scholar 

  22. Voogd, J. 1995. Cerebellum. Pages 310–311, in Paxinos, G. (ed.), The Rat Nervous System. Academic Press, San Diego.

    Google Scholar 

  23. Koller, K. J., Zaczec, R., and Coyle, J. T. 1984. N-acetylaspartylglutamate: Regional levels in rat brain and the effects of brain lesions as determined by a new HPLC method. J. Neurochem. 51:163–171.

    Google Scholar 

  24. Birken, D. L. and Oldendorf, W. H. 1989. N-acetyl-L-aspartic acid: A literature review of a compound prominent in 1H-NMR spectroscopic studies of brain. Neurosci. Biobehav. Rev. 13:23–31.

    Google Scholar 

  25. Passani, L. A., Vonsattel, J. P., Carter, R. E., and Coyle, J. T. 1997. N-acetylaspartylglutamate, N-acetylaspartate, and N-acetylated alpha-linked acidic dipeptidase in human brain and their alterations in Huntington and Alzheimer's diseases. Mol. Chem. Neuropathol. 31:97–118.

    Google Scholar 

  26. Petroff, O. A., Ogino, T., and Alger J. R. 1988. High-resolution proton magnetic resonance spectroscopy of rabbit brain: Regional metabolite levels and postmortem changes. J. Neurochem. 51:163–171.

    Google Scholar 

  27. van Zijl, P. C. and Moonen, C. T. 1993. In situ changes in purine nucleotide and N-acetyl concentrations upon inducing global ischemia in cat brain. Magn. Reson. Med. 29:381–385.

    Google Scholar 

  28. Higuchi, T., Fernandez, E. J., Maudsley, A. A., and Weiner, M. W. 1993. Mapping of cerebral metabolites in rats by 1H magnetic resonance spectroscopic imaging. Distribution of metabolites in normal brain and postmortem changes. NMR Biomed. 6:311–317.

    Google Scholar 

  29. Geddes, J. W., Chang, N. G., Ackley, D. C., Soultanian, N. S., McGillis, J. P., and Yokel, R. A. 1999. Postmortem elevation in extracellular glutamate in the rat hippocampus when brain temperature is maintained at physiological levels: Implications for the use of human brain autopsy tissues. Brain Res. 831:104–112.

    Google Scholar 

  30. Baslow, M. H., Suckow, R., Sapirstein, V., and Hungund, B. L. 1999. Expression of aspartocyclase activity in cultured rat microglial cells is limited to oligodendrocytes. J. Mol. Neurosci. 13:47–53.

    Google Scholar 

  31. Goldstein, F. B. 1976. Aminohydrolases of brain, enzymatic hydrolysis of N-acetyl-L-aspartate and other N-acyl-L-amino acids. J. Neurochem. 26:45–49.

    Google Scholar 

  32. Tyson, R. L. and Sutherland, G. R. 1998. Labeling of N-acetylaspartate and N-acetylaspartylglutamate in rat neocortex, hippocampus and cerebellum from [1–13C]glucose. Neurosci. Lett. 251:181–184.

    Google Scholar 

  33. Berger, U. V., Luthi-Carter, R., Passani, L. A., Elkabes, S., Black, I., Konradi, C., and Coyle, J. T. 1999. Glutamate carboxypeptidase II is expressed by astrocytes in the adult rat nervous system. J. Neurocytol. 25:499–512.

    Google Scholar 

  34. Thomas, A. G., Vornov, J. J, Olkowoski, J. L., Merion, A. T., and Slusher, B. S. 2000. N-acetylated α-linked acidic dipeptidase converts N-acetylaspartylglutamate from a neuroprotectant to a neurotoxin. J. Pharmacol. Exp. Ther. 295:16–22.

    Google Scholar 

  35. Choi, D. W. 1992. Excitotoxic cell death. J. Neurobiol. 23:1261–1276.

    Google Scholar 

  36. Slusher, B. S., Vornov, J. J., Thomas, A. G., Hurn, P. D., Harukuni, I., Bhardwaj, A., Traystman, R. J., Robinson, M. B., Britton, P., May Lu, X. C., Tortella, F. C., Wozniak, K. M., Yudkoff, M., Potter, B. M., and Jackson, P. F. 1999. Selective inhibition of NAALADase, which converts NAAG to glutamate, reduces ischemic brain injury. Nat. Med. 5:1396–1402.

    Google Scholar 

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Battistuta, J., Bjartmar, C. & Trapp, B.D. Postmortem Degradation of N-Acetyl Aspartate and N-Acetyl Aspartylglutamate: An HPLC Analysis of Different Rat CNS Regions. Neurochem Res 26, 695–702 (2001). https://doi.org/10.1023/A:1010947605921

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