The glymphatic system and meningeal lymphatic vessels provide the brain's primary waste clearance pathway. Dysfunction of these systems contributes to tau accumulation and propagation in CBS/PSP.
The glymphatic system is a perivascular network that facilitates:
| Component | Function | Therapeutic Target |
|---|---|---|
| Aquaporin-4 (AQP4) | Water channel on astrocyte endfeet | AQP4 modulators |
| Perivascular space | CSF-ISF exchange conduit | Pulsation enhancers |
| Meningeal lymphatics | Drainage to cervical lymph nodes | Lymphangiogenesis |
| Arachnoid granulations | CSF outflow to venous sinus | Outflow enhancement |
NREM slow-wave sleep is the primary state for glymphatic clearance:
| Intervention | Mechanism | Evidence Level |
|---|---|---|
| Sleep optimization | Maximize NREM duration | Clinical |
| Sedative hypnotics | Enhance slow-wave sleep | Preliminary |
| Optogenetic activation | Direct neuronal silencing | Preclinical |
| Transcranial stimulation | Induce slow oscillations | Phase 1/2 |
AQP4 on astrocyte endfeet is critical for glymphatic function:
| Agent | Target | Developer | Stage |
|---|---|---|---|
| TGN-020 | AQP4 inhibitor | Academic | Preclinical |
| AQP4 modulators | Various | Multiple | Discovery |
Meningeal lymphatic vessels drain CSF and immune cells to cervical lymph nodes:
| Approach | Mechanism | Status |
|---|---|---|
| VEGF-C delivery | Lymphangiogenesis | Preclinical |
| Mechanical massage | Flow enhancement | Clinical |
| Focused ultrasound | Lymphatic activation | Phase 1/2 |
| Lymphatic transplantation | Cellular therapy | Preclinical |
For the CBS/PSP patient (50-year-old male, alpha-synuclein negative, on levodopa/rasagiline):
| Current Medication | Interaction | Recommendation |
|---|---|---|
| Levodopa | No direct interaction | Standard dosing |
| Rasagiline | No direct interaction | Standard dosing |
| Factor | Score | Rationale |
|---|---|---|
| Scientific Rationale | 7/10 | Strong biological plausibility in tauopathy |
| Clinical Readiness | 4/10 | Early-stage programs, limited direct CBS/PSP data |
| Brain Delivery | 5/10 | Endogenous clearance pathway, not delivery-dependent |
| Safety Profile | 7/10 | Sleep optimization and existing agents have good safety |
| Total | 23/50 | 46% |