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Oxidative damage to DNA in plaques of MS brains
O Vladimirova1, J O'Connor, A Cahill
1Center for Neurovirology, Allegheny University of the Health Sciences, Philadelphia, PA 19102, USA.
Abstract:
A major cause of clinical disability in multiple sclerosis (MS) is related to a degenerative process in the central nervous system (CNS) which ultimately develops from a potentially reversible inflammation and demyelination. The mechanism of this degenerative process within MS lesions is not completely understood. We hypothesize that oxidative damage to DNA secondary to inflammation may contribute to irreversible tissue alterations in a plaque. To test this assumption, we determined the level of a DNA oxidative marker, 8-hydroxy-deoxy-guanosine (8-OH-dG) in the normal appearing white matter (NAWM), plaque and cortical regions of cerebella from MS patients who suffered from severe cerebellar symptoms during the course of the disease, and in NAWM and cortical regions of cerebella from non-neurological controls. We found a significant increase in DNA oxidation within plaques compared to NAWM specimens in MS cerebella. A tendency for increase of oxidative markers in normal appearing cortical tissues located in the proximity of MS plaques was also observed when compared to those in control cortical specimens. Oxidative damage to DNA in MS lesions, and in neuron rich areas located in the proximity of these lesions is likely related to the release of reactive oxygen species (ROS) and nitric oxide (NO) during inflammation in the brain. This biochemical impairment of DNA and of other macromolecules may contribute to the development of severe clinical disability through the induction of degenerative changes within and outside of plaques in MS brains.
Insights
Oxidative DNA damage, marked by 8-hydroxy-deoxy-guanosine (8-OH-dG), is elevated in multiple sclerosis (MS) plaques. This damage may drive neurodegeneration and clinical disability in MS patients.
Area of Science:
- Neuroscience
- Immunology
- Genetics
Background:
- Multiple sclerosis (MS) causes significant clinical disability through central nervous system (CNS) degeneration.
- The precise mechanisms driving MS-related neurodegeneration, particularly within lesions, remain incompletely understood.
- Oxidative stress is implicated in inflammatory and degenerative diseases.
Purpose of the Study:
- To investigate the role of oxidative DNA damage in the pathogenesis of MS.
- To quantify levels of 8-hydroxy-deoxy-guanosine (8-OH-dG), a marker of DNA oxidation, in MS brain tissue.
- To correlate DNA oxidation levels with MS lesions and clinical symptoms.
Main Methods:
- Measurement of 8-OH-dG levels in cerebellar white matter (normal-appearing and plaque regions) and cortical tissue from MS patients and non-neurological controls.
- Comparison of 8-OH-dG levels between different tissue types and patient groups.
- Analysis of potential correlation between oxidative damage and disease severity.
Main Results:
- Significantly increased levels of DNA oxidation (8-OH-dG) were found in MS plaques compared to normal-appearing white matter (NAWM) in MS cerebella.
- A trend towards increased oxidative markers was observed in normal-appearing cortical tissues near MS plaques compared to controls.
- These findings suggest localized oxidative stress within and around MS lesions.
Conclusions:
- Oxidative damage to DNA, evidenced by elevated 8-OH-dG, occurs within MS lesions and adjacent areas.
- The release of reactive oxygen species (ROS) and nitric oxide (NO) during neuroinflammation likely contributes to this DNA damage.
- This biochemical impairment may drive irreversible degenerative changes, contributing to severe clinical disability in MS.