Parkinson’s Stem Cell Research
The ability to use adult stem cells as a source of neural stem cells aids researchers looking for ways around both ethical and technical problems in Parkinson’s Disease research. Induced pluripotent stem cells from autologous tissue (the patients’ own stem cells) means that immunological problems are largely avoidable and also constitutes a renewable stem cell source for both research and treatment potential. Long-term outcomes from those trials completed around ten years ago demonstrate that the effects of the disease were not fully eradicated by stem cell treatment as pathology has been found to have spread to the implanted material. Further study is, therefore, essential in order to assess the viability, safety, and efficacy of stem cell therapy for Parkinson’s Disease, and patients are discouraged from undergoing any unproven and untested therapy at commercial clinics due to serious safety concerns. Clinical trials are being developed and these represent the best opportunity for patients to access new and innovative treatments in a safer environment.
Current and Emerging Treatments for Parkinson’s Disease
Treatments for Parkinson’s usually involve the use of exogenous dopamine analogs and medication which attempts to slow the rate of dopamine-producing nerve cell destruction. There is no known cure for Parkinson’s Disease and careful control of medication is needed as the effects tend to wear off during the day with symptoms returning. Medications for Parkinson’s Disease can cause hallucinations, diarrhoea, delirium, nausea, and vomiting and do not always work for patients, especially for those with advanced forms of the disease. Common medications include those which aim to increase dopamine itself, such as Levodopa (L-dopa), Sinemet, Atamet, Pramipexole, Selegiline, and rasagiline, Amantadine for initial mild tremors, and Entacapone which can help prevent levodopa breakdown.
Dopamine medications may affect a patient’s personality, making them more extroverted or impulsive, which can be extremely disruptive for both them and their family. The medications may also lead to the development of motor complications and other abnormalities when used chronically, with these newer symptoms not treatable with further medications. Infrequently, surgery may be used to treat very severe Parkinson’s Disease. This is reserved for those who are no longer responding to medications and aim to remove brain tissue which may be causing the disease’s symptoms or using deep brain stimulation (DBS) to aid movement.
Stem Cells and Parkinson’s Disease: Problems
For many years the presence of de novo generation of neurons in the brain was thought to be restricted after perinatal development meaning that regeneration of damaged brain tissue in adult patients, such as those with Parkinson’s Disease, was thought to be extremely limited, if not impossible. In recent times however, it has been discovered that there is a persistent germinal zone in the central nervous system, with neural stem cell niches existing that could be a potential source for stem cell therapy development. These neural stem cells exist in the subgranular layer of the hippocampus and the subependymal zone of the brain and scientists have extracted neural stem cells from these areas and cultivated new neural cells in the laboratory. Research has also shown that neural stem cells can also be cultivated from spinal cord tissue, bone marrow, and even adipose-derived stem cells making less invasive autologous stem cell sourcing increasingly possible.
Unwanted Stem Cell Differentiation
Animal and human embryonic stem cells have also been used in research although these present problems when implanted into living tissue as the proliferation and differentiation of the pluripotent stem cells can create undesirable growth patterns and tissue types. Indeed, there is one case report of a patient undergoing a stem cell transplant for Parkinson’s Disease, using hESCs, which noted the development of bone, skin, and hair cells in the area of infusion during an autopsy of the patient. It appears that the patient’s death was connected to an obstruction caused by this material which highlights concerns over abnormal tissue development following intraparenchymal stem cell transplantation (Hagell, et al, 2001) . The availability of stem cell treatments at clinics around the world for Parkinson’s Disease presents a worrying situation as these treatments have no evidence of safety or effectiveness and yet are heavily marketed at vulnerable patients and their families.
Which Stem Cells To Use in Parkinson’s Treatment
The major problems for stem cell research into Parkinson’s Disease treatments include the determination of the best kinds of stem cells to use in treatments (whether embryonic, haematopoietic, bone marrow, or adipose-derived), along with learning which conditions best facilitate stem cell differentiation into dopaminergic neurons. Understanding the effects of specific gene expression, and neural stem cell regulation signals in the central nervous system are key to ensuring that implanted stem cells actually produce the desired cell types and effects.
Read More –> The Future of Stem Cell Research for Parkinson’s Disease
