What causes Parkinson’s?
We know that the motor symptoms of Parkinson’s are caused by the death of dopamine-producing cells in the brain. The chemical dopamine is an essential part of the process by which the brain transmits messages to other parts of the body. We don’t know why these cells die.
These are some of the theories:
- Parkinson’s might enter the body via the stomach or the nose, like a virus. This, it is argued, is why constipation and/or loss of the sense of smell are early symptoms.
- Cells might die because of abnormal behaviour (termed misfolding) by a protein called alpha-synuclein. It ‘spreads’ from cell to cell in a chain like process. Researchers are looking to develop ways of ‘blocking’ this process.
- Cells might ‘run out of power’ as mitochondria fail (these generate chemical energy within the cell).
- There are documented cases where exposure to certain chemicals may cause Parkinson’s. However, not everyone who is exposed develops Parkinson’s and the great majority of those who contract the condition have never been near dangerous chemicals.
- Nine genes have been associated with Parkinson’s. In a small number of cases the cause is genetic. However, even if someone has one or more of these genes it is not certain that they will get Parkinson’s
Latest developments in Parkinson’s research
Since the second World Parkinson Research congress in Glasgow in 2010 a few things have changed.
What has changed and how?
- The value of researchers and patients/carers working together to design and carry out research has been embraced enthusiastically by all sides.
- There are definite benefits to patient involvement at all stages of research. I don’t remember this as being an issue five years ago.
- It is recognised, perhaps rather late in the day, that Parkinson’s may not be a single condition, but a number of different diseases and sub-types.
- This may be why, over the years, quite promising drugs have ultimately failed in testing – leading edge research is now seeking to identify at an early stage the patient groups that are likely to benefit.
- This has led to the concept of personalised medicine – treatment specific to patients or patient groups.
- This, in turn, has led to a re-examination of different drugs which may be suitable for treating Parkinson’s – drug repurposing.
- The role of alpha-synuclein in disease pathology.
- Five years ago abnormal behaviour of this protein in the brain was known to be related to Parkinson’s. We now understand much more about how it works and research is being conducted into ways of modifying the abnormal behaviour.
- However, we still don’t know what alpha-synuclein is supposed to be doing in the brain.
- Non-motor symptoms are well and truly on the agenda and a question from this direction accompanies most academic conference presentations.
- This is an area that is difficult to research and, consequently, very little research has been carried out.
- A study by Parkinson’s UK has shown that falls are the most important unmet need for people with Parkinson’s. Fear of falling leads to a loss of confidence and a reluctance to leave home. If falls and balance can be addressed by therapies aimed at tackling the motor symptoms this will go some way to providing an environment that enhances quality of life, which should help to reduce some non-motor symptoms.
See http://bmjopen.bmj.com/content/4/12/e006434.full for details of the article.
What hasn’t changed?
- We don’t know what causes Parkinson’s, and considering how much we do know it is perhaps surprising that we still don’t know the answer to this question.
- It is hoped that it will take another five years before a viable neuro-protective or disease modifying treatment can be seen as an outcome of current research.
What else do we need?
- More work to identify different types of Parkinson’s using an epidemiological approach. The only reported data that I have seen in this area is the presentation by Dr Michelle Hu from the Oxford Parkinson’s Disease Centre where cluster analysis is used to identify different population segments.
Are there different types of Parkinson’s?
How to find out more about Parkinson’s
If you are interested in finding out more about Parkinson’s Research, you can join the Parkinson’s UK Research Support Network, web site address:
Richard Windle – June 2016
A leaflet with more information is available from Parkinson’s UK: Parkinson’s UK Information Leaflet