Clinical Trials

Inclusion Criteria: 

• Adult patients (n=48, 30-86 years old, females and males) who have grade 1-3 Hoehn and Yahr motor manifestations of Parkinson disease; patients receiving a stable dose of L-dopa with no changes in the last 3 months (metabolic precursor of dopamine) are eligible to participate. Also allowed amantadine (Symmetrel)
• Participants receiving their medical care at Mayo Clinic in Rochester, MN or in the Mayo Clinic Health System. Patients will have been evaluated by physicians (neurologists) at Mayo Clinic, Rochester, MN.
• Among patients with Parkinson disease, 24 will have gastrointestinal symptoms (e.g., heartburn, nausea, constipation) and 24 will have no GI symptoms.
• 24 adult healthy controls (30-86 years old, females and males) without PD and without GI symptoms. The rationale for including controls without GI symptoms is based on the need to assess the SPECIFICITY of the findings in the disease groups.  For example, α-synuclein and Lewy bodies have been identified in myenteric neurons of elderly patients without PD (79B, C, D).  Therefore it is important to assess the diverse endpoints in age matched controls to understand the biological relevance of the observations in patients with PD and particularly in patients with PD and gastrointestinal symptoms.

Exclusion Criteria:

• Currently receiving medications that impair GI functions e.g. GLP-1 agonists, pramlintide, calcium channel blockers, tricyclic antidepressants (a stable dose of 25 mg is allowed)
• Currently receiving dopamine agonists ( Requip, Ropinirole and Rotigotine), MAO inhibitors (Rasagiline)  or anticholinergic medications (Artane) for the Parkinson disease will not be allowed to participate.
• Prior gastrointestinal surgery that could interfere with the conduct or interpretation of the studies.
• Pregnancy or breast-feeding will be exclusion criteria.
• Parkinson disease with grade 4 or above Hoehn and Yahr motor manifestations.
• Patients with established diagnosis of diabetes mellitus associated with objectively documented autonomic neuropathy will be excluded.
• Any condition that, in the assessment of the investigators would place the patient at risk of harm e.g. intravenous sedation if there is any respiratory compromise at baseline.
• Vulnerable populations including Parkinson dementia that would compromise informed consent process.
• Any condition or personal circumstance that, in the opinion of the investigator, renders the subject unlikely or unable to comply with the full study protocol or could interfere with the study assessments.
• Allergy to Eggs or Ensure® Original Formula (suitable for lactose intolerance, gluten-free, Kosher/Halal). Subjects with lactose intolerance may take Lactacid® or lactase enzyme before ingesting milk or other foods in the testing from their own home supply if they wish.
• Oral or injected antibiotic use in the prior 4 weeks of the stool sample and optional endoscopies.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 06/12/2024. Questions regarding updates should be directed to the study team contact.