Multiple sclerosis, or MS, is the most common neurological disease in young adults, and can interfere with their personal and professional lives. The greatest number of cases are diagnosed between 30 and 40 years of age, and it is more common among women than men.
Multiple sclerosis (MS) is the most common chronic neurological disease which affects predominantly young people and interferes with their personal and professional lives. The greatest number of cases occurs between the ages of 30 and 40 years of age. Whilst men and women are both affected there is a history of it occurring in more women than in men. Its cause is totally unknown. There is a plethora of suggested causes, which range from abnormal copper metabolism to the effect of cosmic radiation. However, clinical and epidemiological studies strongly suggest the influence of genetics, environment and geographical location.
The voluminous literature that has purported to prove that MS is an immunologically mediated disorder has failed to be supported by rigorous scientific analysis. Yet another hypothesis has appeared on the horizon for explaining MS, known as chronic cerebro-spinal venous insufficiency or CCSVI. As we will show, it too clearly has failed to convince.
Multiple sclerosis: the facts
There is evidence to show that when a person of susceptible stock migrates from a high-risk area, such as Scotland, to a low risk area such as South Africa, the likelihood of developing the disease is significantly related to the age at the time of migration. This pattern is also found inversely with migration in the opposite direction. There is a curious relationship with latitude, in that MS is more prevalent in the northern hemisphere, with an increasing incidence the further one moves from the equator. The disease occurs in most races, although, curiously, not in some, including American Indians, Inuits, Australian Aborigines and Maoris. Although there are clearly differences in susceptibility between races, the results of epidemiological studies are not explicable. The likelihood of developing MS increases significantly if one has a first-degree relative with the disease. The rate of concordance in identical twins is 35 per cent, which also confirms a genetic influence, but leaves many questions unanswered. Sophisticated modern genetic analyses have failed to demonstrate a precise genetic anomaly. To date there is no confirmed cure, or any significant treatment that is more effective than placebo.
In MS the permeability of cerebral capillaries is increased, as demonstrated by studies on post-mortem material and neuroimaging techniques. This phenomenon is called breakdown of the blood-brain barrier (BBB) and it appears to be an integral part of the pathological process. If this barrier is compromised, by a variety of other pathological conditions, in a patient with existing MS, it has been shown that new fresh lesions will occur at this site in the brain. There is no connection that has been proven between blood-brain barrier defects and CCSVI.
Multiple sclerosis: the fictions
Multiple sclerosis is stated in most textbooks and journals as being an autoimmune disease, meaning that the immune system of the body is directed against putative brain components. But this hypothesis is incorrect, based on a misinterpretation of histological studies and comparison of the disease to an animal model.
The autoimmune hypothesis has allowed investigators and drug firms to use and test powerful immunomodulating and immunosuppressive agents as therapy. Sadly, such trials persist despite recognised morbidity and mortality among patients.
A review of papers published over the course of 60 years in one of the world’s leading journals in medicine shows that many research articles claim to show that it has an immunological basis. But, alas, not one of these claims has been confirmed, despite glowing editorials at the time of publication.
The latest hypothesis concerns the role of the aforementioned condition, chronic cerebro-spinal venous insufficiency (CCSVI). The proponents of CCSVI claim that there is an anomaly in the venous drainage from the brain. Some state that this condition arises as a result of multiple sclerosis, while others propose that it is a developmental abnormality. Those convinced of its existence believe that manipulation may clinically improve multiple sclerosis, and claim that the anomaly is to be found in 100 per cent of MS patients and not in healthy controls. Others claim that it is statistically abnormal in MS patients but also found in healthy individuals; further studies have shown it to occur in healthy patients without any evidence of multiple sclerosis, and yet further groups have found it not in patients with multiple sclerosis but with other neurological conditions. Further, CCSVI has been claimed to be involved in a purported autoimmune process in MS.
Such a tangled web of controversies surround CCSVI that it is impossible even to define what the condition is. Another consideration often overlooked is the financial cost to the patient. Indeed, in a chronic disease that has normal life expectancy, pharmaceutical firms would regard a drug with any proven efficacy as a substantial prize. Treatment of CCSVI will be subject to the same considerations.
The prospect of a cure or a treatment offering some relief in multiple sclerosis has enormous appeal and raises, as in this case, the hopes and aspirations of patients. Sadly, the proposition that CCSVI causes multiple sclerosis is yet another example of hope dashed on the rocks of reality.
Peter Behan is Professor Emeritus of Neurology at University of Glasgow. Simone Hutchinson is Research Assistant at Glasgow Caledonian University.
http://www.telegraph.co.uk/health/healthnews/8443111/Multiple-sclerosis-the-facts-and-fictions.html