Early Research Holds Promise For Stem Cell Therapies With Fewer Side Effects, UK

Main Category: Multiple Sclerosis
Also Included In: Stem Cell Research
Article Date: 04 Dec 2007 - 4:00 PDT

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Early stage studies at the Stanford University School of Medicine have taken a small but significant step toward the goal of transplanting adult stem cells to create a new immune system which may help people with autoimmune conditions such as Multiple Sclerosis (MS).

One of the hopes for stem cell work is that in the future, adult stem cells may able to be used to replace the immune system (thought to mis-fire in MS) and in that way prevent the damage caused in MS.

In the small studies currently occurring using this technique in humans, strong drugs (the same as those used in chemotherapy) are used to knock out the body's immune system and then the person's bone marrow is replaced (using bone marrow from a donor or the persons own preserved bone marrow stem cells) in order to replace the immune system. Since the immune system is mis-functioning, it is hoped this should prevent further MS damage.

This type of treatment is controversial because of severe side effects such as infertility, brain damage and an increased risk of cancer, and clinical trials are continuing in people with very severe forms of MS for whom there are few treatment options.

The new research investigates a method for transplanting new stem cells into the bone marrow of mice, effectively replacing their immune systems. Before transplanting new stem cells, the old ones first must be removed. This involves injecting the mice with molecules that latch on to specific proteins on the surface of the stem cells, effectively destroying the cells. That technique eliminated the old stem cells without otherwise harming the mice.

When new stem cells are transplanted into the mice, they take up residence in the bone marrow and establish a new blood and immune system.

Many aspects of the technique would need to be adapted before it can be tested in humans and there are still significant barriers to be overcome. It is not known if the same specific protein on human blood-forming stem cells would be the right one to target with a therapy. Also, the mice used in the study lack a functioning immune system. The study will need to be repeated to ensure it works in mice with a normal immune system before it can be tested in humans. This means trials in humans are still several years away.

http://www.mssociety.org.uk