What are stem cells?

Stem cells are immature cells that have the potential to differentiate into any type of mature cell in the body. The sources of stem cells being researched are :

• Embryonic stem cells from fertilized eggs– they can be made to develop into any type of cell.
• Neural stem cells from embryonic or adult brain– they develop only into nerve cells.
• Mesenchymal stem cells from other tissues.
• Immature stem cells from human (umbilical) cord blood.

Replacement of the degenerated neurons, in a case of Parkinson’s disease, by stem cell transplantation is the basis of treatment that is being studied. The concept is to take stem cells and grow them into neurons, which can then be transplanted into the brain of the patient.

Possibilities of Stem Cell Therapy as a Parkinson’s Cure

The choice of treatment offered to a patient with Parkinson’s disease all have their own limitations.

• Drug therapy is the first line of treatment but they have various side effects and their efficacy decreases as the disease progresses.
• Surgery offers no significant additional benefits.
• Embryonic mesencephalic tissue transplantation has been tried but the results are unstable and there are not enough embryonic donors.

In this scenario, stem cell therapy offers hope, not only for treatment of symptoms of Parkinson’s disease, but possibly for the reversal and halting or slowing down the progression of the disease.

Dopamine cells have been successfully transplanted in the brain of patients with Parkinson’s disease which have led to initial improvement of symptoms such as tremor, slowness of movement, rigidity, and difficulties in balance and posture.

In vitro engineering of stem cells to dopamine neurons, prior to implantation in the brain of a patient with Parkinson’s disease, is being researched to overcome the ethical and practical issues of using fetal dopamine neurons.

The finding of neural stem cells in the adult brain has opened up possibilities of using the patients own neural stem cells to grow dopamine neurons for transplantation into his brain, thereby avoiding the issue of an immune reaction. However, other factors have to be considered such as whether surgery is advisable on the already diseased brain of a patient with Parkinson’s disease.

Limitations of Stem Cell Therapy as a Parkinson’s Cure

There are various ethical, practical, safety and technical issues associated with stem cell therapy.

• Shortage of suitable donor tissue is a major issue in cell replacement therapy in Parkinson’s disease.
• The ethical issue of using fetal dopamine neurons for transplantation into the brain of a patient with Parkinson’s disease.
• Authentic dopamine neurons with correct midbrain identity need to be developed to be able to treat Parkinson’s disease patient effectively.
• Treatment with transplanted dopamine cells gives good initial response but the transplanted cells may become diseased over time.

Stage 4 of Parkinson’s Disease

In this stage, the main difficulty is in maintaining balance and posture, so patients need assistance while standing and walking. Increase in tremor, rigidity (increased tone) and bradykinesia (slowness of movement) as the disease progresses make the performance of routine tasks difficult without help. Falls tend to occur more often. The patient is mobile at this stage but needs help to carry on with their daily tasks.

Stage 5 of Parkinson’s Disease

At this stage of the disease, the patient is unable to stand or walk and constant nursing care is needed as they cannot function independently. A number of patients also suffer from dementia, depression or hallucinations, which further aggravates the situation.

Features of the End Stages of Parkinson’s

The end stages of Parkinson’s disease can be extremely difficult and heart-breaking, both for the patient and his close relatives and friends.

• There is progressive worsening of symptoms despite of drug therapy.
• Tremor increases gradually, and in the later stages there may be action tremor (like an essential tremor) whereas initially there was tremor only at rest, thus making performance of routine tasks difficult.
• Unsteadiness in walking or turning, resulting in falls, become more pronounced as the disease progresses and ultimately the patient can only stand or walk with help, while in the end stage he becomes completely bedridden.
• Dementia and depression occur in a large number of patients of Parkinson’s disease towards the end stages of the disease and anxiety, mood changes and insomnia may be an associated symptom.
• Dysphagia or difficulty in swallowing often leads to less intake of food and nutrients, causing weight loss, weakness and tiredness.
• Constipation is often troublesome and may be a side effect of anticholinergic treatment.
• Recurrent infections occur such as pneumonia.
• Improper bladder control may lead to urgency and frequency.
• Hypersalivation or drooling is common due to difficulty in swallowing and may lead to choking.
• Memory loss – both recent and long term.
• Confusion and hallucinations become more pronounced in elderly patients being treated with anticholinergics.
• Pain and discomfort in the lower part of the body and limbs.
• There is progressive difficulty in speech with slow, soft, monotonous voice and the patient may have problem finding words.
• There may be dyspnea or difficulty in breathing.

In the end stages, the patient becomes totally helpless and cannot survive without a care-giver. They are unable to sit, talk, walk, turn around in bed, control bladder or bowel movements, or conduct any bodily function on their own. Combined with their gradually declining health status, both physical and mental, the end stage leads to death ultimately. Unfortunately, there are no medicines yet that can cure Parkinson’s disease but  only help to alleviate the symptoms or delay progression of the disease.