Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease and Lou Gehrig’s disease, is a rare condition caused by the degeneration of nerve cells that control voluntary muscles. The disease is characterized by gradually worsening symptoms that include muscle weakness, muscle twitching and muscle stiffness. The muscles gradually decrease in size, eventually resulting in problems with speaking, swallowing, and breathing.
There is no cure or effective treatment for the disease, and more than half of patients die within three years after the onset of symptoms. But effective therapies for ALS are being pursued constantly.
Stem cell therapy for ALS
Stem cell therapy is emerging as a potential approach for the treatment of ALS. There are many types of stem cells researchers use in their attempts to find an effective treatment for ALS. Induced pluripotent stem cells are among the most promising tools in these investigations.
Alternatively, mesenchymal stem cells can be taken from the patient’s own bone marrow or fat tissue and then modified to boost their production of neurotrophic factors. Neurotrophic factors are molecules known to help support and protect neurons that are destroyed by the disease. Immature stem cells also can be transformed into motor neurons, the cells affected in ALS patients.
Gene therapy for ALS
Gene therapy is based on delivering a healthy copy of genes that are malfunctioning in a patient. The presence of the healthy genes may improve, or even reverse, the damage caused by the disease.
In an attempt to treat ALS, researchers inserted a gene encoding for glial cell-derived neurotrophic factor (GDNF) into stem cells capable of differentiating into astrocytes. GDNF is a growth factor known to enhance the survival of many types of nerve cells. Astrocytes are a type of cells protecting neurons. This approach, which has not yet been tested in human clinical trials, combines stem cell therapy and gene therapy into a single treatment.
A Phase 1/2 open label study (NCT01051882) evaluated the safety, tolerability, and therapeutic effects of cultured mesenchymal bone marrow stromal cells secreting neurotrophic factors in ALS patients with early and progressive disease. The study enrolled 24 patients and was completed in March 2013. The cells were directly injected into the muscle tissue of the patients.
Another, Phase 2a prospective study (NCT01777646) enrolled 14 patients to check the effects of combined multiple injections of the same cells into muscle tissue with a single injection into the fluid surrounding the brain and spinal cord. (This process is called intrathecal administration.)
The results reported in 2016 in the journal JAMA Neurology demonstrated that the treatment was safe and well-tolerated, resulting in a decreased rate of disease progression during six months after the injections, as compared to six months before treatment.
The safety of intrathecal treatment with mesenchymal stromal cells derived from fat tissue also was investigated and appeared to be safe at the tested doses in ALS.
Although findings from stem cell research appear to be promising, a recent systematic review on the subject concluded there is a lack of high-quality evidence to guide the practice on the use of stem cell therapies for the treatment of ALS in the clinic.