Effect of Biological Sex on Multimodal Biomarkers of Disease Progression in Patients with Parkinson's Disease

Overview:

The GENDERIZE-PD study investigates how biological sex influences the progression of Parkinson's disease (PD). This groundbreaking project seeks to uncover sex-specific differences in clinical symptoms, disease progression, and biomarkers to enable more personalized and equitable treatment strategies for men and women. By examining a range of biological, clinical, and imaging data, the study aims to provide a deeper understanding of the disease and identify predictors of progression.

Background and Rationale:

PD is a progressive neurodegenerative disorder characterized by motor symptoms (e.g., tremors, rigidity) and non-motor symptoms (e.g., mood disturbances, sleep problems). The disease affects men nearly twice as often as women, and differences between the sexes have been observed in clinical presentations and treatment responses:

• Men with PD are more likely to experience cognitive decline.
• Women with PD are at higher risk of treatment-related motor complications.

Emerging evidence suggests that biological sex impacts brain structure and function, potentially influencing the course of neurodegenerative diseases like PD. Hormonal factors, such as testosterone and estrogen, play key roles in brain health and disease susceptibility. This study seeks to clarify these sex-based differences by analyzing clinical, biological, and neuroimaging data.

Objectives:

The study is designed to achieve the following:

1. Primary Objective: Identify clinical differences between men and women with early-stage PD, focusing on motor and non-motor symptoms, and correlate these findings with sex hormone levels.
2. Secondary Objectives: Investigate sex-specific differences in brain imaging results, including MRI and dopamine transporter (DAT) scans, and biomarker profiles.
3. Exploratory Objectives: Evaluate the predictive value of biomarkers for disease progression and explore sex-independent patterns of PD progression.

Study Design:

This is a multicenter, observational, prospective, case-control study with a longitudinal follow-up of 18 months. The research involves three Italian centers:

1. San Raffaele Scientific Institute - Milan
2. University of Campania "Luigi Vanvitelli" - Naples
3. University "Magna Graecia" - Catanzaro

Study Phases:

1. Baseline Cross-Sectional Analysis: Collect clinical, imaging, and biological data to establish sex-specific profiles at the onset of the study.
2. Longitudinal Follow-Up: Monitor participants over 18 months to track disease progression and evaluate changes in biomarkers.

Participants:

• Total Enrollment: 210 participants.
• 120 individuals with early-stage PD (60 men, 60 women).
• 90 healthy controls (45 men, 45 women).
• Inclusion Criteria: Participants aged 18-80 years with idiopathic early-stage PD (diagnosed within 3 years), Hoehn \& Yahr stage ≤2.5, or healthy individuals without neurological disorders.
• Exclusion Criteria: Conditions such as major depression, dementia, or premenopausal status (for women).

Procedures:

Participants will undergo:

• Clinical Assessments: Evaluations of motor (e.g., MDS-UPDRS) and non-motor symptoms (e.g., sleep, mood, fatigue scales).
• Blood Tests: Analysis of hormone levels (e.g., testosterone, SHBG) and calculation of the Free Androgen Index.
• Neuroimaging:
• MRI: Examine structural and functional changes in the brain.
• DAT Scans: Assess dopamine transporter binding levels.
• Questionnaires and Interviews: Assess emotional well-being, cognitive function, and quality of life.

Outcome Measures:

• Primary Outcomes: Sex-related differences in clinical and biomarker profiles at baseline and follow-up.
• Secondary Outcomes: Correlations between neuroimaging findings and clinical measures.
• Exploratory Outcomes: Biomarker trajectories over time and their predictive value for disease progression.

Significance:

This study addresses critical gaps in understanding sex-based differences in PD. By integrating clinical, biological, and imaging data, the results could:

• Improve understanding of PD's natural history.
• Highlight the importance of considering sex as a factor in research and treatment design.
• Lead to more personalized and equitable healthcare strategies.

Funding and Ethical Considerations:

The study is funded by the European Union's NextGenerationEU initiative and the Italian Ministry of University and Research (PRIN). It adheres to the Declaration of Helsinki, Good Clinical Practice guidelines, and all relevant regulatory standards. Written informed consent will be obtained from all participants before enrollment.

Implications for Future Research:

Findings from the GENDERIZE-PD study will inform the design of sex-specific clinical trials and potentially contribute to the development of disease-modifying therapies. By considering sex as a key biological variable, this research aims to set a new standard for inclusivity and precision in PD care.