🧫 Experiment Protocol
Exploratorycognitive impairment and dementiahuman patientsproposed
This longitudinal study examined the associations between five different epigenetic clocks measured at baseline and two brain aging measures derived from structural MRI scans obtained approximately 8 years later. The study focused on 1,196 older women and investigated whether epigenetic age acceleration is associated with brain structural changes indicative of aging and Alzheimer's disease pathology. The epigenetic clocks included various measures of biological age acceleration based on DNA methylation patterns. The brain aging measures included the Spatial Pattern of Atrophy for Recognition of Brain Aging (SPARE-BA), which captures general brain aging patterns, and the Alzheimer's Disease Pattern Similarity Score (AD-PS), which reflects structural changes characteristic of Alzheimer's disease. Linear regression models were used to assess associations while controlling for relevant demographic and health-related covariates. The study found no significant associations between any epigenetic clock and SPARE-BA, but identified a significant positive association between AgeAccelGrim2 and AD-PS. Further analysis revealed this association was primarily driven by DNA methylation markers of smoking pack years and their relationship with frontal and temporal lobe volumes, rather than hippocampal or entorhinal cortex volumes typically associated with early Alzheimer's disease.
PRIMARY OUTCOME
Association between epigenetic clocks and brain aging patterns (SPARE-BA and AD-PS)
EXPECTED OUTCOMES
Expected to find associations between epigenetic age acceleration and accelerated brain aging patterns, particularly those associated with dementia risk
SUCCESS CRITERIA
- Prespecified primary endpoint (Association between epigenetic clocks and brain aging patterns (SPARE-BA and AD-PS)) improves versus control with p < 0.05 or an equivalent corrected threshold used by the study.
- The effect size is biologically meaningful and reproduced across technical/biological replicates or the validation subset.
- Safety, data quality, and missingness remain within protocol-defined bounds so the result is interpretable rather than driven by attrition or assay failure.
PROTOCOL
1. Establish human patients cohorts for cognitive impairment and dementia and predefine inclusion, exclusion, and quality-control criteria before intervention. 2. Apply the experimental manipulation described for the nominated disease mechanism, alongside matched control or comparator arms, and document dose, exposure window, and sample timing in a locked protocol log. 3. Measure Association between epigenetic clocks and brain aging patterns (SPARE-BA and AD-PS) together with orthogonal secondary readouts such as molecular, imaging, behavioral, or safety endpoints that are appropriate to the title and study design. 4. Use blinded outcome assessment where feasible, prespecified statistical analysis, and replicate the core readout across biological replicates or an independent validation subset. 5. Interpret results against the baseline study rationale: This longitudinal study examined the associations between five different epigenetic clocks measured at baseline and two brain aging measures derived from structural MRI scans obtained approximately 8 years later. The study focused on 1,196 older women and inve