# Domain Expert Assessment: SST/PV Interneuron Dysfunction in Alzheimer's Disease
## Question 1: Highest Translational Potential Hypotheses
Based on the current Alzheimer's therapeutic landscape—dominated by amyloid-targeting agents with modest efficacy and significant side effects—I identify three hypotheses with the strongest translational potential:
### Hypothesis A: Interneuron Dysfunction as Primary Pathology (Model B)
**Rationale**: This model opens a therapeutic avenue orthogonal to amyloid, addressing a mechanism that persists even after amyloid removal. Given the ceiling effects observed with anti-amyloid antibodies (27-35% slowing of progression in pivotal trials), identifying downstream drivers is critical. If interneuron loss is primary, preservation strategies could extend clinical benefit beyond amyloid clearance.
### Hypothesis B: Amyloid–Interneuron Interaction as Stratification Biomarker
**Rationale**: Not all amyloid-positive individuals progress similarly. Interneuron vulnerability may explain the "amyloid non-responder" phenotype—patients who clear amyloid but continue to decline. Testing interneuron biomarkers in ongoing lecanemab/donanemab extension studies could identify subpopulations needing add-on therapy. This is immediately feasible given the active trial infrastructure.
### Hypothesis C: SST/PV-Selective Vulnerability as Mechanistic Target
**Rationale**: If specific molecular features (e.g., parvalbumin calcium buffering, metabolic demands) explain selective interneuron vulnerability, this creates a precision therapeutic target. This has the highest risk but also the highest reward if validated.
---
## Question 2: Evidence, Safety, and Patient Population Fit
### Hypothesis A: SST/PV Function Preservation
**Current Clinical Evidence**
| Source | Finding | Stage |
|--------|---------|-------|
| Verret et al., 2012 | PV+ basket cell loss precedes plaque formation in APP/PS1 mice | Preclinical |
| two | CSF somatostatin declines in MCI/AD, correlates with cognitive decline | Clinical (exploratory) |
| Campdelacreu et al. | Lower cortical SST in AD postmortem | Postmortem |
The clinical evidence is largely correlative