Parkinson's disease is not one, but two diseases

Date:
September 22, 2020
Source:
Aarhus University
Summary:
Researchers around the world have been puzzled by the different
symptoms and varied disease pathways of Parkinson's patients. A
major study has now identified that there are actually two types
of the disease.



FULL STORY ========================================================================== Although the name may suggest otherwise, Parkinson's disease is not one
but two diseases, starting either in the brain or in the intestines. Which explains why patients with Parkinson's describe widely differing symptoms,
and points towards personalised medicine as the way forward for people
with Parkinson's disease.


==========================================================================
This is the conclusion of a study which has just been published in the
leading neurology journal Brain.

The researchers behind the study are Professor Per Borghammer and Medical Doctor Jacob Horsager from the Department of Clinical Medicine at Aarhus University and Aarhus University Hospital, Denmark.

"With the help of advanced scanning techniques, we've shown that
Parkinson's disease can be divided into two variants, which start in
different places in the body. For some patients, the disease starts
in the intestines and spreads from there to the brain through neural connections. For others, the disease starts in the brain and spreads
to the intestines and other organs such as the heart," explains Per
Borghammer.

He also points out that the discovery could be very significant for
the treatment of Parkinson's disease in the future, as this ought to be
based on the individual patient's disease pattern.

Parkinson's disease is characterised by slow deterioration of the
brain due to accumulated alpha-synuclein, a protein that damages nerve
cells. This leads to the slow, stiff movements which many people associate
with the disease.



==========================================================================
In the study, the researchers have used advanced PET and MRI imaging
techniques to examine people with Parkinson's disease. People who have
not yet been diagnosed but have a high risk of developing the disease
are also included in the study. People diagnosed with REM sleep behaviour syndrome have an increased risk of developing Parkinson's disease.

The study showed that some patients had damage to the brain's dopamine
system before damage in the intestines and heart occurred. In other
patients, scans revealed damage to the nervous systems of the intestines
and heart before the damage in the brain's dopamine system was visible.

This knowledge is important and it challenges the understanding
of Parkinson's disease that has been prevalent until now, says Per
Borghammer.

"Until now, many people have viewed the disease as relatively homogeneous
and defined it based on the classical movement disorders. But at the
same time, we've been puzzled about why there was such a big difference
between patient symptoms. With this new knowledge, the different symptoms
make more sense and this is also the perspective in which future research should be viewed," he says.

The researchers refer to the two types of Parkinson's disease as
body-first and brain-first. In the case of body-first, it may be
particularly interesting to study the composition of bacteria in the
intestines known as the microbiota.



==========================================================================
"It has long since been demonstrated that Parkinson's patients have a
different microbiome in the intestines than healthy people, without us
truly understanding the significance of this. Now that we're able to
identify the two types of Parkinson's disease, we can examine the risk
factors and possible genetic factors that may be different for the two
types. The next step is to examine whether, for example, body-first
Parkinson's disease can be treated by treating the intestines with
faeces transplantation or in other ways that affect the microbiome,"
says Per Borghammer.

"The discovery of brain-first Parkinson's is a bigger challenge. This
variant of the disease is probably relatively symptom-free until the
movement disorder symptoms appear and the patient is diagnosed with Parkinson's. By then the patient has already lost more than half of the dopamine system, and it will therefore be more difficult to find patients
early enough to be able to slow the disease," says Per Borghammer.

The study from Aarhus University is longitudinal, i.e. the participants
are called in again after three and six years so that all of the
examinations and scans can be repeated. According to Per Borghammer, this
makes the study the most comprehensive ever, and it provides researchers
with valuable knowledge and clarification about Parkinson's disease --
or diseases.

"Previous studies have indicated that there could be more than one type
of Parkinson's, but this has not been demonstrated clearly until this
study, which was specifically designed to clarify this question. We now
have knowledge that offers hope for better and more targeted treatment
of people who are affected by Parkinson's disease in the future," says
Per Borghammer.

According to the Danish Parkinson's Disease Association, there are
8,000 people with Parkinson's disease in Denmark and up to eight million diagnosed patients worldwide.

This figure is expected to increase to 15 million in 2050 due to the
ageing population, as the risk of getting Parkinson's disease increases dramatically the older the population becomes.


========================================================================== Story Source: Materials provided by Aarhus_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jacob Horsager, Katrine B Andersen, Karoline Knudsen, Casper
Skjaerbaek,
Tatyana D Fedorova, Niels Okkels, Eva Schaeffer, Sarah K Bonkat,
Jacob Geday, Marit Otto, Michael Sommerauer, Erik H Danielsen,
Einar Bech, Jonas Kraft, Ole L Munk, Sandra D Hansen, Nicola
Pavese, Robert Go"der, David J Brooks, Daniela Berg, Per
Borghammer. Brain-first versus body- first Parkinson's disease:
a multimodal imaging case-control study.

Brain, 2020; DOI: 10.1093/brain/awaa238 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200922092156.htm

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