Immunity versus Degeneration
There is a growing view that MS is not just about the immune system. Degeneration is also likely to be a key mechanism in MS, particularly in progressive phases of the disease. Wikipedia defines a degenerative disease as ‘a disease in which the function or structure of the affected tissues or organs will progressively deteriorate over time, whether due to normal bodily wear or lifestyle choices such as exercise or eating habits’. It gives some examples of degenerative diseases as Alzheimer’s disease, motor neurone disease, cancer, diabetes, heart disease, inflammatory bowel disease, Parkinson’s disease and osteoarthritis. The growing evidence of a degenerative component to MS means that many lifestyle interventions such as diet and exercise which are known to be helpful in other degenerative diseases, will also be of benefit to people with MS, and provides further rationale for why they are effective in MS.
The evidence that MS is not just an immune system disorder but also a degenerative disorder is extensive. For instance, there is currently much research into the contribution of plasma homocysteine to various degenerative disorders, including coronary heart disease and atherosclerosis, but also to a variety of degenerative diseases of the nervous system.1 It has been found that plasma homocysteine is also elevated in MS 2 and that its level correlates with the degree of cognitive and motor impairment.3
There is also MRI evidence that the process of degeneration of nerve cells begins very early in MS and is not just a feature of the progressive phases of the illness.4,5 These authors found that damage to the CNS is very widespread in MS and is not just confined to the ‘lesions’ that are seen on standard MRI. They felt that the concept of MS as a focal, demyelinating disease needs to be re-examined, and that we should now regard it as a diffuse disease of the CNS with a major degenerative component. This is supported by German neuropathologists, who have pointed out that damage to the CNS is widespread in MS, is degenerative in nature, and not just confined to demyelinating lesions.6,7 The accumulating loss of nervous tissue does seem to be what ultimately leads the disease to become progressive.
Another study of the effect of interferon given early to people likely to progress to MS showed quite a disparity between the number of new lesions and the loss of brain volume.4 This suggests that the immune-mediated inflammation and the neurodegeneration in MS are separate processes right from the beginning of the disease. There is now much opinion that the distinction between immune and degenerative diseases of the nervous system is becoming blurred, and that both processes probably contribute to many neurological diseases, typified by MS.8,9
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There is also MRI evidence that the process of degeneration of nerve cells begins very early in MS and is not just a feature of the progressive phases of the illness.4,5 These authors found that damage to the CNS is very widespread in MS and is not just confined to the ‘lesions’ that are seen on standard MRI. They felt that the concept of MS as a focal, demyelinating disease needs to be re-examined, and that we should now regard it as a diffuse disease of the CNS with a major degenerative component. This is supported by German neuropathologists, who have pointed out that damage to the CNS is widespread in MS, is degenerative in nature, and not just confined to demyelinating lesions.6,7 The accumulating loss of nervous tissue does seem to be what ultimately leads the disease to become progressive.
Another study of the effect of interferon given early to people likely to progress to MS showed quite a disparity between the number of new lesions and the loss of brain volume.4 This suggests that the immune-mediated inflammation and the neurodegeneration in MS are separate processes right from the beginning of the disease. There is now much opinion that the distinction between immune and degenerative diseases of the nervous system is becoming blurred, and that both processes probably contribute to many neurological diseases, typified by MS.8,9
- Shea TB, Lyons-Weiler J, Rogers E. Homocysteine, folate deprivation and Alzheimer neuropathology. J Alzheimers Dis 2002; 4:261-267
- Ramsaransing GS, Fokkema MR, Teelken A, et al. Plasma homocysteine levels in multiple sclerosis. J Neurol Neurosurg Psychiatry 2006; 77:189-192
- Teunissen CE, van Boxtel MP, Jolles J, et al. Homocysteine in relation to cognitive performance in pathological and non-pathological conditions. Clin Chem Lab Med 2005; 43:1089-1095
- Filippi M, Rovaris M, Inglese M, et al. Interferon beta-1a for brain tissue loss in patients at presentation with syndromes suggestive of multiple sclerosis: a randomised, double-blind,
- placebo-controlled trial. Lancet 2004; 364:1489-1496
- Filippi M, Rocca MA. MRI evidence for multiple sclerosis as a diffuse disease of the central nervous system. J Neurol 2005; 252 Suppl 5:v16-v24
- Bruck W. The pathology of multiple sclerosis is the result of focal inflammatory demyelination with axonal damage. J Neurol 2005; 252 Suppl 5:v3-v9
- Bruck W. Inflammatory demyelination is not central to the pathogenesis of multiple sclerosis. J Neurol 2005; 252 Suppl 5:v10-v15
- Zipp F, Aktas O. The brain as a target of inflammation: common pathways link inflammatory and neurodegenerative diseases. Trends Neurosci 2006
- Shea TB, Lyons-Weiler J, Rogers E. Homocysteine, folate deprivation and Alzheimer neuropathology. J Alzheimers Dis 2002; 4:261-267
- Ramsaransing GS, Fokkema MR, Teelken A, et al. Plasma homocysteine levels in multiple sclerosis. J Neurol Neurosurg Psychiatry 2006; 77:189-192
- Teunissen CE, van Boxtel MP, Jolles J, et al. Homocysteine in relation to cognitive performance in pathological and non-pathological conditions. Clin Chem Lab Med 2005; 43:1089-1095
- Filippi M, Rovaris M, Inglese M, et al. Interferon beta-1a for brain tissue loss in patients at presentation with syndromes suggestive of multiple sclerosis: a randomised, double-blind,
- placebo-controlled trial. Lancet 2004; 364:1489-1496
- Filippi M, Rocca MA. MRI evidence for multiple sclerosis as a diffuse disease of the central nervous system. J Neurol 2005; 252 Suppl 5:v16-v24
- Bruck W. The pathology of multiple sclerosis is the result of focal inflammatory demyelination with axonal damage. J Neurol 2005; 252 Suppl 5:v3-v9
- Bruck W. Inflammatory demyelination is not central to the pathogenesis of multiple sclerosis. J Neurol 2005; 252 Suppl 5:v10-v15
- Zipp F, Aktas O. The brain as a target of inflammation: common pathways link inflammatory and neurodegenerative diseases. Trends Neurosci 2006