As all patients with MS are aware, the currently available treatments do nothing to cure the disease or repair the damage that it does. At their best, todays crop of disease modifying drugs (DMDs) quiet the disease, thereby improving the quality of life for many of the patients taking them, especially those suffering from relapsing remitting multiple sclerosis. However, many of these drugs carry with them risky side effect profiles, and though the newest compounds represent advances over their predecessors, patients are crying out for revolution, not evolution.
Stem cells could represent the revolution patients so fervently desire. Because of their ability to transform into almost any type of cell in the human body, stem cells may hold the key to achieving one of the holy grails of modern medicine, the regeneration and repair of damaged tissues. For MS patients, this could potentially mean the reversal of disability, and with it the long dreamt of disposal of wheelchairs, walkers, and canes. We are still a long way from that lofty goal, however, but the first few steps along the path to that salvation are currently being taken.
Though stem cell research is advancing in laboratories worldwide, the science of using stem cells to treat diseases in humans is still in its infancy. Because multiple sclerosis is a neurodegenerative disease, and its most prominent feature is the damage the disease does to the central nervous system, it is hoped that stem cells may hold the key to reversing the carnage wrought by the disease by facilitating the repair of damaged nerve cells. Furthermore, research has provided hints that stem cells may modulate the abnormal immune response seen in MS patients, and some researchers are even using stem cells to completely reboot the human immune system, a process that in some cases appears to stop the disease dead in its tracks.
Its important to understand that there are two very different approaches to using stem cells in the treatment of multiple sclerosis. One approach hopes to use the cells to repair damaged nervous systems; the other uses stem cells to provide the patient with a brand-new immune system, one that theoretically will not turn against a patients own body. The latter approach is known as hematopoietic stem cell transplant, or HSCT, and has been used on patients in trial settings for almost two decades.
HSCT involves ablating (destroying) a patients existing immune system through the use of powerful chemotherapy drugs, and then intravenously infusing a patients own stem cells back into their body, a process depicted in the below diagram:
As you might imagine, using powerful chemotherapy drugs to destroy a patients immune system is not without its dangers, and early attempts at this therapy had mortality rates as high as 10%. As researchers perfected their methodology and began using less dangerous chemotherapy agents, though, the risks associated with HSCT dropped dramatically. Today, most patients undergoing HSCT are subjected to chemotherapy and immunosuppressive agents that do not completely destroy their bone marrow, and the safety profile of the procedure has improved impressively. The results achieved by this HSCT can be dramatic. In one study (click here) that looked at the long-term outcomes of HSCT, after 11 years 44% of patients who had started out with aggressive relapsing remitting disease were free from disability progression. By comparison, only 10% of those who did not display signs of active inflammation before HSCT remained stable.
One of the primary proponents of HSCT therapy for MS patients, Dr. Richard Burt of Northwestern University, stresses that the proper selection of patients is the key to the success of the treatment. In fact, the title of the paper he recently published (click here) includes the phrase if no inflammation, no response. Its the only therapy to date that has been shown to reverse neurologic deficits, said Dr. Burt, But you have to get the right group of patients. In a study published by Dr. Burt in 2009, 17 out of 21 relapsing remitting patients improved after HSCT, and after three years all patients were free from progression (click here). Dr. Burt is currently heading up the HALT-MS trial for HSCT (click here). There are several centers around the world offering HSCT therapy, and there is a Worldwide HSCT Facebook group (click here) that contains information on all of the legitimate HSCT facilities worldwide. The group is populated by many folks who have undergone HSCT therapy. Be aware that its a private group, and you must request membership before being given access to all of the available information.
While HSCT holds much promise for putting the brakes on very aggressive relapsing remitting multiple sclerosis, it unfortunately has little to offer those with progressive disease, and does nothing to directly repair the damage done to the central nervous system by MS. Fortunately, another form of stem cell therapy proposes to do just that. Researchers in two centers in the US have received FDA approval to use bone marrow derived mesenchymal stem cells (MSCs) to repair nervous system damage, thereby possibly reversing the effects of the disease. There are additional trials using MSCs to treat MS underway internationally. Mesenchymal stem cells have the ability to transform (differentiate) into many different cell types, and could prove to be the building blocks necessary for repairing damage to the central nervous system as well as other organs and tissues. Experiments using MSCs to treat animal models of MS have been very encouraging (click here), demonstrating the cells abilities to modulate the immune system and spur the repair of damaged nervous system tissues. It remains to be seen whether the same effects can be achieved when using the cells to treat human beings.
The two FDA approved studies both use MSCs harvested from a patients own bone marrow, but employ them in very different ways. One study, currently underway at the Cleveland Clinic (click here), infuses mesenchymal stem cells intravenously into the patient, in the expectation that the cells will modulate the immune system and also initiate the regeneration of damaged tissues in the central nervous system. This study, which will eventually use MSCs to treat 24 patients, is proceeding slowly, but as the above linked to article details, one of the first patients treated is already reporting encouraging results.
The second FDA approved trial, to be conducted by the Tisch MS Research Center of New York (which just so happens to be my MS clinic), will use mesenchymal stem cells that have been transformed through a proprietary laboratory process into neural progenitor (NP) cells, injected directly into the spinal fluid (intrathecally)) of the patient (click here). Neural progenitor cells are a specialized type of stem cell specific to the nervous system that have the ability to transform into the various types of tissues damaged and destroyed by the MS disease process. Researchers at the Tisch Center have developed a way to get mesenchymal stem cells to differentiate into neural progenitor cells, and hope that by injecting these cells directly into the spinal fluid the NP cells will directly target the regenerative mechanisms of the central nervous system (click here). The stem cells themselves may act to repair damaged tissues, but theyve also been shown to have the ability to recruit existing stem cells within the brain and spinal cord to jumpstart the bodys own repair mechanisms.
Read more here:
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