Dr Paul Eggleton, Senior Lecturer in Immunology in University of Exeter Medical School and Visiting Professor University of Alberta writes about the use of oxygen therapy for patients with MS.
This article first appeared in The Conversation.
Paul Eggleton, University of Exeter
There is no cure for multiple sclerosis (MS) yet. As a complex neurodegenerative disease of the brain, it is incredibly difficult to treat. Despite the development of new and sophisticated therapies to control the inflammation and physical symptoms of the disease, these treatments don’t work for everyone. This is because MS comes in many guises and one treatment does not fit all. Perhaps for this reason people with MS are turning to alternative means of controlling their condition.
Many of the 100,000 people with MS in the UK have taken charge of managing their treatment. With the assistance of 60 or more independent charitable MS therapy centres, people with the disease regularly enter a chamber and breathe oxygen under moderate pressure (hyperbaric oxygen). Some people have done so for more than 20 years.
The air we breathe contains 21% oxygen, but 100% oxygen is considered a drug and is prescribed in hospitals to aid people’s recovery. In the case of MS, people self-prescribe the hyperbaric oxygen, which is delivered to them by trained operators. But does breathing pure oxygen under pressure on a weekly basis do them any good?
The idea to use oxygen as a treatment for MS began over 45 years ago. In 1970, two Romanian doctors, Boschetty and Cernoch, treated patients with brain injuries with pressurised oxygen to help more oxygen enter their tissues – oxygen helps protect nerve cells from damage and maintains the integrity of the blood-brain barrier. In a study of MS patients, they found that symptoms in 15 out of 26 volunteers improved. This led to further interest in the use of hyperbaric oxygen to treat MS specifically.
Since Boschetty and Cernoch’s discovery, around 14 clinical trials have been conducted. The trials have been on relatively small numbers of people and have reported conflicting results, ranging from great improvements to none at all. This has led to a dilemma: should clinicians endorse the use of hyperbaric oxygen for MS or not?
Not officially sanctioned
The clinical regulatory bodies in the US and the UK, the FDA and NICE respectively, do not feel the clinical trial evidence is strong enough to endorse the procedure, yet thousands of people in the UK and elsewhere continue to treat themselves with hyperbaric oxygen. Between 1982 and 2011, over 20,000 people with MS in the UK used hyperbaric oxygen over 2.5m times.
Multiple sclerosis is a chronic inflammatory disease of the brain. It is usually diagnosed between the ages of 20 and 40. Lesions in the brain develop as a result of inflammatory autoimmune cells crossing the blood-brain barrier and destroying the protective protein coat (myelin) that surrounds the axon of some nerve cells. Over time MS develops into a neurodegenerative disease, leading to problems with vision, bladder control and mobility.
The brain’s ability to repair some of this damage helps people with MS to feel better for a while before relapsing once more. Eventually the disease becomes chronic and the ability to repair the damage and undergo remission declines. Most conventional treatments focus on the early phases of the disease. Unfortunately, there are few treatments for the later stages of MS.
Perhaps the inability of prescribed drugs that work for all people with MS, or indeed work for some but produce unpleasant side-effects, has driven people to seek other treatments. Despite the scepticism of some doctors, many people with MS claim that hyperbaric oxygen therapy has benefits. The benefits include improvements in mobility, bladder control, pain relief and gait. However, since the treatment is transient, regular exposure to pressurised oxygen is required to sustain any benefit.
The increase in oxygen to the brain may lead to a number of effects such as speeding repair to damaged tissue, or inhibiting the ability of immune cells to cross the blood-brain barrier and cause damage. These possibilities are being investigated.
Poorly designed trials
So why are many clinicians sceptical of hyperbaric oxygen? The main reason is various MS disability-status scores are used to judge improvement. In the former clinical trials, hyperbaric oxygen was not used over a sustained periods of time (only a few weeks) and often people with irreversible damage were used, so no or very little improvement in scores was seen.
So are poorly controlled clinical trials to blame for the conflict of opinion? Probably, yes. Until we understand more at the molecular level about how oxygen under pressure can make sustained changes to various biological processes in the brain, people with MS will continue to use the treatment and the majority of the medical community will remain unconvinced of its merits.
Paul Eggleton, Senior lecturer in Immunology, University of Exeter
This article was originally published on The Conversation. Read the original article.