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NCT Number: NCT07097103

Parkinson's Research In Metagenomic Early Stage Biomarkers

This 2x2 factorial, randomized, controlled pilot study aims to identify a specific microbiota pattern, which could constitute a biomarker of Parkinson's disease, and to evaluate whether specific pathotypes can be associated with different stages of the disease; furthermore, the investigators are committed to evaluating how and to what extent the changes induced by a personalized nutritional intervention combined with physical exercise affect the symptoms and quality of life of patients.

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Key information

Conditions

Parkinson's Disease (PD) Behavior Motor Activity

Age range

35 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Casa di Cura San Raffale Cassino, Cassino, Frosinone, Italy

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About this study

The study will last 60 months, and the following activities are planned:

  • Study presentation, selection and enrollment of patients;
  • Evaluation of patients' health and nutritional status, including collection of physiological, pathological, and pharmacological history;
  • Randomization of patients into four groups;
  • Sample collection and storage;
  • Microbiome analysis;
  • Evaluation of motor and non-motor symptoms using clinical tests and rating scales at baseline (T0), at six months (T1) after treatment initiation, and at three and six months post-intervention (FU1 and FU2, respectively).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of Parkinson's disease according to United Kingdom (UK) Parkinson's Disease Society Brain Bank criteria;
  • aged 35-80 years;
  • Hoehn & Yahr stage > 1 and < 3 in the clinical "ON" state;
  • MoCA score ≥17.54;
  • MMSE ≥24;
  • Stable dopaminergic midication regimen for ≥ 4 weeks;
  • Ability to interact with the research team and provide informed consent in Italian;
  • Suitable to physical exercise;
  • Able to walk unassisted (no walking aids);
  • Willingness and ability to comply with all study procedures;
  • Willingness to maintain usual diet during a ≥ 4-week pre-baseline period;
  • Willingness to switch to a Mediterranean-style diet during the intervention;
  • Ability to provide stool samples at each collection timepoint;
  • Willing to avoid strenuous exercise and alcohol for 24 hours prior to each visits.

Exclusion criteria

  • Pre-existing psychiatric disorders;
  • Atypical or secondary Parkinsonism;
  • Presence of pacemakers or other subcutaneous electronic devices;
  • Any other neurological or neurodegenerative disorders;
  • Moderate to severe cognitive decline;
  • Beck Depression Inventory-II (BDI-II)] score ≥28;
  • Dementia diagnosis;
  • Thyroid dysfunctions;
  • Type1 Diabetes Mellitus;
  • Type 2 diabetes mellitus with HbA₁c ≥ 8% or on insulin therapy;
  • Acute diseases;
  • Active Neoplasia;
  • IBD or IBS;
  • Celiac disease;
  • History of major gastrointestinal surgery or acute GI conditions (e.g., gastroenteritis) within the past 3-6 months;
  • Chronic corticosteroid therapy;
  • Use of proton pump inhibitors within the past 30 days;
  • Acute, antibiotic-resistant infections;
  • Antibiotic intake within the past 30 days;
  • Prebiotic/probiotic supplement use in the past 30 days;
  • Prolonged intake of anxiolytic drugs, antidepressants, antipsychotics, cognitive stimulants, and analogs in the past 3 months;
  • Underweight (BMI <18.5);
  • History of deep brain stimulation (DBS) surgery;
  • Pregnancy or lactation;
  • Regular use of enemas or suppositories to alleviate constipation;
  • Use of experimental products in the 3 months prior to the screening visit
  • Patients who, for medical reasons, are required to follow special dietary regimens that could interfere with the adoption or effectiveness of the Mediterranean model;
  • Vegan/Vegetarian diet or any other dietary behaviour that excludes one or more of the typical food groups of the Mediterranean model.

Treatment and study plan

Mediterranean Diet Intervention

Behavioral

Participants will follow a personalized diet plan over 24 weeks, based on the guidelines of the Mediterranean diet and defined according to their needs and the state of the disease; no food category will be excluded a priori. Individualized nutritional counseling and support materials (weekly meal plans, sample recipes, portion guides) will be provided by a qualified nutritionist. Adherence to the Mediterranean diet will be monitored periodically. Participants will maintain their usual diet during a pre-baseline period of at least 4 weeks, then switch to the Mediterranean plan under the supervision of a nutritionist.

Intensive Physical Activity Intervention

Behavioral

Participants will perform exercise, over 24 weeks, according to WHO recommendations for adults, including those aged ≥ 64 years, to achieve at least 150-300 minutes of moderate-intensity aerobic physical activity, or at least 75-100 minutes of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate and vigorous activity during the week. The WHO 2020 also recommend moderate-intensity or greater muscle-strengthening exercises involving alla major muscle groups for 2 or more days per week. Adherence will be monitored during in-person sessions and through wearable devices for activity tracking.

Control

Other

Participants will continue their usual medical management for early Parkinson's disease according to current clinical guidelines, without any additional dietary or exercise interventions provided by the study, and will be monitored through standard follow-up visits but will not receive any study-specific dietary or physical activity programs.

Primary outcomes

  1. Alpha Diversity of the fecal microbiota.

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in fecal microbiota alpha diversity, a measure of the richness and evenness of microbial species within a sample, will be assessed.

  2. Beta Diversity of the fecal microbiota

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in fecal microbiota beta diversity, refers to the degree of difference in microbial community composition between different fecal samples, will be assessed.

  3. Enterobacteriaceae species abundance across Parkinson's disease stage

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in fecal microbial composition will be assessed. Specifically, we will measure the relative abundance of Enterobacteriaceae species and pathotypes across different stages of Parkinson's disease.

  4. Fecal Microbial relative quantification

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in relative quantification

Secondary outcomes

  1. Intestinal Inflammation

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in fecal calprotectin (a valid and non-invasive marker of mucosal inflammation) will be assessed using enzyme-linked immunosorbent assay (ELISA).

  2. Intestinal Permeability

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in fecal zonulin will be assessed using enzyme-linked immunosorbent assay (ELISA). The unit for measuring zonulin in stool samples is nanograms per milliliter (ng/mL). The Protein Zonulin is a very important indicator for leaky gut.

  3. Changes in extracellular vesicle concentration (particles/mL) in saliva and plasma will be assessed.

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    To evaluate the effect of the combined diet and physical activity intervention on extracellular vesicles (EVs), EVs will be isolated from saliva and plasma by serial ultracentrifugation and size-exclusion chromatography. EV concentration and size distribution will be determined by nanoparticle tracking analysis (NTA).

  4. Changes in protein marker expression in saliva and plasma.

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Extracellular Vesicles (EVs)-associated proteins (CD63, CD9, α-synuclein, BDNF, L1CAM, and CD56) will be quantified by dot blot and confirmed by fluorescent NTA and/or cytofluorimetric analysis.

Other outcomes

  1. Total score on the Digestion-Associated Quality of Life Questionnaire (DQLQ)

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Participants will complete the Digestion-Associated Quality of Life Questionnaire (DQLQ) for a total of 9 statements. Possible totale score ranges from 0 to 9, with a higher score indicates a lower (worse) digestion-associated QoL

  2. Changes in non-motor symptoms MDS-UPDRS Part I

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part I (non-motor symptoms of daily living) scores will be assessed. The minimum score on the MDS-UPDRS Part I is 0 and the maximum is 52, with higher scores representing worse non-motor symptoms of daily living.

  3. Changes in motor symptoms MDS-UPDRS Part II

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part II (motor symptoms of daily living) scores will be assessed. The minimum score on the MDS-UPDRS Part II is 0 and the maximum is 52, with higher scores representing worse motor symptoms of daily living.

  4. Changes in motor symptoms MDS-UPDRS Part III

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part II (motor examination) scores will be assessed. The minimum score on the MDS-UPDRS Part III is 0 and the maximum is 132, with higher scores representing worse motor symptoms.

  5. Changes in motor symptoms MDS-UPDRS Part IV

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part IV (motor complications) scores will be assessed. The minimum score on the MDS-UPDRS Part IV is 0 and the maximum is 24, with higher scores representing worse motor complications.

  6. Changes in motor symptoms (H&Y)

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in The Hoehn & Yahr scale (H&Y) scale will be assessed. H&Y scale is a system used to describe the progression of motor symptoms in PD - it ranges from Stage 0 (no signs of disease) to Stage 5 (wheelchair-bound or bedridden).

  7. Changes in movement analysis (TUG)

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in the execution time of the Timed Up & Go (TUG) test-a reliable and valid measure of mobility, balance, walking ability, and fall risk-will be assessed.

  8. Change in postural instability

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Berg Balance Scale (BBS), a 14-item objective measure that assesses static balance and fall risk in adults. Each item is scored on a 5-point ordinal scale ranging from 0 to 4, with 0 indicating an inability to complete the task entirely and 4 indicating an ability to independent complete the task ,

  9. Change in movement analysis - propulsion

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in propulsion (anterior-posterior peak acceleration during the lower-limb swing phase, measured by a wearable G-sensor in m/s²) will be assessed.

  10. Change in walking capacity

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in the 10-Meter Walking Test, a standardized method used to assess gait speed and functional mobility.

  11. Changes in Gastrointestinal symptoms

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in "Gastrointestinal Symptom Rating Scale" (GSRS), a specific tool consisting of 15 items, that are grouped into five symptom clusters: reflux, abdominal pain, indigestion, diarrhea, constipation.

  12. Changes in stool types

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Bristol Stool Scale, a diagnostic medical tool designed to classify the form of human faeces into seven categories (Type 1 and 2: May be difficult to pass, may indicate constipation; Type 3 and 4: Ideal stools; Type 5: Trending toward diarrhea; Type 6 and 7: Diarrhea).

  13. Change in non-motor symptoms (NMSS)

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Non-motor Symptom Scale (NMSS), a 30-item scale including the following 9 domains: cardiovascular, sleep/fatigue, mood/cognition, perceptual problems, attention/memory, gastrointestinal, urinary, sexual function and miscellaneous.

  14. Changes in severity of depressive symptomatology

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Beck Depression Inventory-II (BDI-II), a 21-item self-report inventory measuring the severity of depression.

  15. Changes in quality of life

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Parkinson's Disease Questionnaire-39 (PDQ-39), a tool assessing QoL in eight domains (mobility, daily activities, emotional well-being, stigma, social support, knowledge, communication, and physical discomfort). It's a 5-point scale for each of the 39 questions (0=Never; 1=Rarely; 2=Sometimes; 3=Often; 4=Always). The minimum score is 0 means good health, maximum score is 100 means bad health; a higher score indicates a lower QoL.

  16. Changes in cognitive function - Mini-Mental State Examination (MMSE)

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Mini-Mental State Examination (MMSE), a 30-point items to measure cognitive impairment examining functions like registration, attention and calculation, recall, language, ability to follow simple commands and orientation.

  17. Change in cognitive function - Montreal Cognitive Assessment (MoCA)

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Montreal Cognitive Assessment (MoCA), a 10-minute test used to detect cognitive impairment related to PD.

  18. Change in cognitive function - Frontal Assessment Battery (FAB)

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)

    Changes in Frontal Assessment Battery (FAB), a 10 minutes tool evaluating the executive functions located in the frontal lobes, consisting of 6 tests that correspond to each specific cognitive or behavioral domain related to the frontal lobes; FAB scores range between 0 and 18, with higher scores representing a better outcome.

  19. Changes in cognitive abilities

    Time frame: Baseline (Week 0); End of intervention (Week 24); First Follow-up (Week 36); Second Follow-up (Week 48)Chan

    Changes in Clock Drawing Test, a simple tool used to check for signs of dementia, that measures several cognitive abilities at once, including attention, hearing comprehension, visual memory, and motor skills.

Study contacts

Contact information is provided by the study sponsor or research team.

Alice Fognani

CONTACT

[email protected]

+39 0652253440

Lucia Gatta, PhD

CONTACT

[email protected]

+39 0652253440

Sponsors and collaborators

Lead sponsor

IRCCS San Raffaele Roma

Other

Collaborators

  • Northwestern University
  • San Raffaele Telematic University
  • University of Urbino "Carlo Bo"

Registry information

Official study title

A 2x2 Factorial Randomized Controlled Non-pharmacological Interventional Multicenter Pilot Study on the Influence of the Mediterranean Diet and Physical Exercise on the Microbiome of Patients With Parkinson's Disease

Acronym: PRIME_2025

Important dates

Study start
2026
Primary completion
2029
Study completion
2029
First posted
Jul 31, 2025
Registry last updated
Jul 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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