The aim of this study is to investigate the link between gut health and Parkinson's disease

Parkinson's disease (PD) is a common, age-related neurological condition, affecting approximately 145,000 people in the United Kingdom. Diagnostic symptoms include stiffness, tremor, unsteadiness and slow movements. Interestingly, while PD is usually considered to be a neurological condition, pathological changes occur in the gut years before diagnosis, often causing constipation. As such, the gut has attracted attention as a possible therapeutic target.

Previous studies have shown different profiles of gut bacteria and the short chain fatty acids (SCFAs) they produce in people with PD. There is evidence these changes might be significant to the disease course, as faecal transplants from people with PD worsened symptoms in a mouse model of PD. The mechanism for this is unclear, but changes in SCFAs and gut wall inflammation, have both been suggested. Studies so far have compared gut bacteria in people with and without PD, however, as the healthy controls often don't have constipation, it is unclear if the differences seen are due to PD itself or the associated constipation.

This pilot study aims to determine differences in the frequency of gut micro-organisms (bacteria, fungi and archaea) and gut function, other than those caused by constipation. 40 participants with a new diagnosis of PD will be recruited from Movement Disorder clinics within National Health Service (NHS) Grampian. 40 healthy (non-PD) controls will be recruited from the PD participants households (whenever feasible). All 80 participants will be clinically assessed and asked to provide two stool samples. The samples will be analysed for the frequency of gut micro-organisms, changes in gut function (short chain fatty acid concentrations) and gut inflammation (calprotectin concentrations).

The aim of this pilot study is to determine the key differences in gut micro-organisms in PD compared to controls, which may have a role in disease progression. It is likely that the results of this proof of concept study would need to be confirmed in a larger study before the investigators are able to plan an intervention trial, such as testing a prebiotic product, with the aim of normalising gut micro-organisms, and potentially modifying the disease course.

Inclusion Criteria:

Participants with Parkinson's disease 2. Community-dwelling patients with newly diagnosed PD who have not yet started medication for Parkinson's disease.

Control Participants

1. Healthy (non-Parkinsonian) members of the participants household will be invited to act as controls.

Exclusion Criteria:

1. Use of oral or intravenous antibiotics in the last 8 weeks.
2. Active gastrointestinal disease, not including constipation or irritable bowel syndrome without other symptoms.
3. Current use of medications which cause/worsen constipation e.g., opioids, tramadol, gabapentin, pregabalin.
4. Potential controls will be excluded if they report prodromal symptoms of PD, such as anosmia or rapid eye movement (REM) sleep disorder or display parkinsonian signs on examination.
5. Inability to give informed consent at any stage of the study e.g., because of dementia.

Parkinson disease group: potential participants will be invited into the study if they have recently been diagnosed with Parkinson's disease and have not yet started medication for the condition

Control group: spouses or other household contacts will be invited to the study