Parkinson's disease is the result of the loss of dopamine-producing brain cells, many of which are already lost by the time most people are diagnosed with the condition. Thus far, treatment has focused on symptom management — with medications, lifestyle changes, physical therapy, and deep brain stimulation surgery all playing possible roles. None of these methods reserve the damage that has been done within the brain, nor do they slow the progression of the disease, however. What's more, pharmacological treatment for Parkinson's disease, such as levodopa, is known to become increasingly less effective as the disease progresses to later stages. A new treatment is hoghly sough-after, then.
What do Parkinson's disease patients and their loved ones need to know about stem cell treatment?
What are stem cells?
Stem cells are unspecialized cells that hold the potential to become many different kinds of more specialized cells — and though the body performs this function of "specializing" stem cells by itself, researchers can also "steer" these cells in the wanted direction. Embryonic stem cells are the most well-known, and these go on to make up all the different kinds of cells a person needs in their body. Adults also have stem cells in their bodies, however — they've been found in the heart, muscles, and bone marrow, among other places, and they can go on to become multiple different kinds of cells from thereon out. The stem cells found in a person's bone marrow specialize into different kinds of blood cells, for example.
Six different stem cell types are:
- Embryonic stem cells (ESCs) are found in early-stage embryos. These kinds of cells can be taken from unused embryos created through IVF.
- Adult derived stem cells or tissue-specific stem cells are found within different organs, from which they can go on to become different kinds of cells. The stem cells found in human bone marrow are currently best understood by scientists, and are already used for medical purposes.
- Induced pluripotent stem cells (iPSCs) are previously specialized cells that have been "reprogrammed" to assume a stem cell-like state.
- Umbilical cord stem cells are also hematopoietic, meaning they give rise to different kinds of blood cells.
- Mesenchymal stem cells or stromal cells can go on to become fat, bone, or cartilage cells. They may hold the potential of treating various conditions as well.
- Human parthenogenetic stem cells come from human eggs (in an unfertilized state).
Why are stem cells an important potential treatment for Parkinson's disease?
Stem cells, including those taken directly from people who have been diagnosed with Parkinson's, are being studied all the time. These unique unspecialized cells can both help researchers come to a greater understanding of the processes that cause brain cells to be lost in Parkinson's disease patients, and eventually lead to a better treatment than is currently available. Who knows? A cure may one day be on the horizon too.
Though this is an exciting time for medical science, it's important to make it clear that we're not there yet. Researchers are still trying to figure out what kinds of stem cells could be used to generate dopamine-producing neurons, how, and how these cells may be transplanted to the brain. Clinical trials are underway, but make no mistake — if you Google "Parkinson's stem cell treatment" or something similar, you may end up with a highly unethical "clinic" that promises costly treatment that has neither been proven to be safe nor effective. More about that later.
Stem cell therapy for Parkinson's disease: The work ahead
Around five percent of Parkinson's disease patients have gene mutations linked to the disease that could be passed down through generations, while the remaining majority of patients do not have any identified genetic component that could be responsible for their Parkinson's. Even in the small percentage of patients with identified genetic mutations, the proteins coded by these genes aren't yet fully understood.
Animal research has indicated that two different kinds of stem cells — ESCs and iPSCs — are likely both safe and effective paths to creating dopamine-producing cells that could one day offer a revolutionary treatment for Parkinson's disease. With human clinical trials now underway, we'll soon find out how well this may work out in practice in the foreseeable future.
The work ahead would now include:
- Establishing the safety, efficacy, and long-term viability of these procedures.
- Finding ethical ways to administer this treatment, through the use of iPSCs and other stem cells that aren't derived from embryos.
- Bringing down the cost of the treatment.