Across the world, nearly three million people live with multiple sclerosis, a condition in which the immune system attacks a protective sheath surrounding nerve cells, often causing gradually worsening disability.
A study last year described the UAE as a “medium to high-risk area”, where the disease, commonly known as MS, shows “a steady increase” in prevalence – but the country is pushing ahead with new potential therapies.
Clinicians have announced the results of the first series of stem cell transplants for MS in the UAE, reporting that some patients have improved disability scores 12 months after treatment, and that none worsened.
The study’s lead author, Dr Ruqqia Mir of Yas Clinic Khalifa City, run by Abu Dhabi Stem Cells Centre, said she and her colleagues were “very encouraged by the results”, although a longer follow-up is needed.
“In a condition such as multiple sclerosis, where disability often progressively worsens over time, the fact that no patient experienced deterioration following treatment is particularly significant,” she said.
“Most patients either remained stable or improved, which represents a meaningful outcome in aggressive MS and is consistent with results reported by leading international centres.”
Encouraging signs
The UAE trial results are published in the January edition of Multiple Sclerosis and Related Disorders. In addition to Yas Clinic Khalifa City and Abu Dhabi Stem Cells Centre, the other authors are from UAE University and institutions in the United States.
Several stem cell treatments for MS exist; the one trialled in the UAE is autologous haematopoietic stem cell transplantation (AHSCT). This involves collecting stem cells – cells that have not yet specialised and can become various cell types – that have been released from the bone marrow into the patient’s bloodstream.
After collection, the patient receives chemotherapy to suppress their immune system before the stem cells are returned. The immune system can then rebuild itself, and ideally, it will no longer attack nerve cells.
AHSCT dates back to the 1990s, when it “was associated with higher risks”, Dr Mir said. Now, treatment-related mortality is “well below 1 per cent” in experienced centres. A lot of research over the decades has focused on how to prepare patients to receive the stem cells for treatment.
“Advances in patient selection, safer conditioning regimens and improved supportive care have significantly enhanced its safety profile,” Dr Mir said. “What was once an experimental approach is now internationally recognised as a standard treatment option for carefully selected patients with highly active MS.”
This stem cell treatment is suitable for some patients with a form of the disease called RRMS, which is characterised by flare-ups interspersed with periods of remission, but not an overall increase in disability. Other forms include primary progressive MS, with gradual worsening of symptoms, and secondary progressive MS, which occurs when RRMS becomes progressive.
All types are associated with damage to the myelin sheath that surrounds nerve cells. This sheath has been compared to the insulation around electrical wires and it ensures that nerve impulses are transmitted effectively. When it is damaged, the transmission of nerve impulses is disrupted, causing the symptoms of MS.
“Great step forward”
Prof Neil Scolding of the University of Bristol said stem cell treatments for MS could be “a great step forward”, because currently no treatments can stop, let alone reverse, the increase in the severity of disability in people with forms of MS in which there is a gradual worsening over time.
He has investigated treatments using bone marrow mesenchymal stem cells to target MS progression. “A treatment targeted specifically at progression, such as the … approach we and others have been exploring, could have a very significant impact – if they finally prove to be effective,” he said.
At a conference in Barcelona last year, Prof Scolding and colleagues reported that in phase II trials, patients who received the treatment had better outcomes than those who did not, although he cautioned that such results were “far from proof” of effectiveness.
Unlike AHSCT, which is being applied to selected RRMS patients outside clinical trials (as in the UAE), the use of mesenchymal stem cells to halt progressive MS remains confined to trials. But unlike AHSCT, if approved, a significant proportion of MS patients could be suitable for this therapy.
“Not every patient with MS will inevitably develop progressive disability – a significant proportion never do (so-called benign MS),” Prof Scolding said. “But unfortunately, this is a minority: most patients eventually develop disability that slowly progresses.
"We currently have very few treatments for progressive disability, and even those show only modest benefit. So any treatment that had a significant impact on progressive MS could indeed be suitable for a large proportion of MS patients.”
Another researcher developing stem cell treatments for progressive MS is Prof Stefano Pluchino of the University of Cambridge. His group and collaborators trialled a method in which neural stem cells, taken from the brain tissue of a single miscarried human foetus, were injected into the brains of 15 MS patients.
None of the patients, who were typically heavily disabled at trial entry, experienced significant worsening during a 12-month period. This suggests that the treatment may be able to stop disability from becoming more severe, or to slow down this process, as without the therapy, a worsening of the condition of some of the patients may have been expected.
Changes in brain chemistry in some analysed participants indicated that the treatment may have been effective at “reprogramming” nerve cells in a way that would ultimately preserve the brain itself.
Another approach uses induced pluripotent stem cells – adult cells reprogrammed to behave like stem cells. Such stem cells, which can turn into a wide range of specialised cell types, are particularly useful to researchers because they have a wide range of uses, yet they do not raise ethical issues in the way that using stem cells from embryos can.
