Metabolic dysfunction, including insulin resistance and type 2 diabetes mellitus (T2DM), represents an emerging area of investigation in progressive supranuclear palsy (PSP). While traditionally considered a tauopathy primarily affecting subcortical structures, growing evidence suggests that systemic metabolic alterations may influence disease pathogenesis, progression, and clinical outcomes. This page synthesizes current evidence on metabolic dysfunction in PSP, drawing from epidemiological studies, neuroimaging findings, biomarker analyses, and mechanistic research.
Population-based studies have examined the relationship between diabetes and PSP risk:
Beyond diabetes, metabolic syndrome components have been studied:
Fluorodeoxyglucose positron emission tomography (FDG-PET) studies reveal characteristic metabolic patterns:
| Region | PSP Pattern | PD Pattern | CBS Pattern | AD Pattern |
|---|---|---|---|---|
| Striatum | ↓↓ Moderate | ↓ Mild | ↓↓ Severe | → Normal |
| Brainstem | ↓↓ Severe | ↓ Mild | ↓ Variable | → Normal |
| Cortex | ↓ Mild-moderate | ↓ Mild | ↓↓ Severe | ↓↓ Severe |
| Cerebellum | → Preserved | → Preserved | ↓ Variable | → Preserved |
The relationship between insulin resistance and brain metabolism:
Peripheral metabolic markers in PSP patients:
Cerebrospinal fluid analysis reveals metabolic clues:
Interactions between tau pathology and metabolic dysfunction:
Metabolic dysfunction affects mitochondrial function:
Bidirectional relationship between inflammation and metabolism:
Metabolic factors influence clinical outcomes:
Metabolic pathways as therapeutic targets:
Recent studies have advanced our understanding of metabolic dysfunction in PSP:
IGF Signaling: Insulin-like growth factor (IGF) signaling pathways are dysregulated in PSP brain tissue, with reduced IGF-1 receptor expression in basal ganglia regions[7]. This finding suggests impaired neurotrophic support through insulin-like signaling cascades.
CSF Glucose Biomarkers: Novel cerebrospinal fluid glucose metabolism markers have been identified that correlate with disease severity in PSP[8]. These include altered lactate-to-pyruvate ratios and impaired glucose transporter function.
Diabetes-Tau Interaction: Type 2 diabetes co-morbidity appears to modify tau pathology burden in PSP, with diabetic PSP patients showing increased tau phosphorylation at specific epitopes (Ser396, Thr181) in postmortem tissue[9]. This suggests metabolic dysfunction may accelerate tau aggregation.
Brain Insulin Resistance: Therapeutic targeting of brain insulin resistance has emerged as a promising approach in 4R-tauopathies[10]. Intranasal insulin and GLP-1 agonists are being investigated for their ability to restore insulin signaling and reduce tau pathology.
This model illustrates how peripheral metabolic dysfunction propagates to the brain and contributes to tau pathology in PSP.
Schmitz A, et al. Type 2 diabetes mellitus and risk of atypical parkinsonism. Movement Disorders. 2024. ↩︎
Moreno G, et al. Brain glucose metabolism in PSP measured by FDG-PET. Neurology. 2023. ↩︎
Bhatia V, et al. Insulin signaling in the pathophysiology of PSP. Journal of Neurochemistry. 2022. ↩︎
Pan Y, et al. Diabetes mellitus and progression of atypical parkinsonism. Journal of Neurology Neurosurgery and Psychiatry. 2024. ↩︎
Andreasson U, et al. CSF biomarkers of neuronal injury in PSP and diabetes. Alzheimer's and Dementia. 2022. ↩︎
Litvan I, et al. Metabolic syndrome and clinical outcomes in PSP. Parkinsonism and Related Disorders. 2021. ↩︎
Chen L, et al. Insulin-like growth factor signaling in PSP brain tissue. Acta Neuropathologica Communications. 2024. ↩︎
Park S, et al. Glucose metabolism biomarkers in PSP cerebrospinal fluid. Movement Disorders. 2024. ↩︎
Kim H, et al. Type 2 diabetes co-morbidity modifies tau pathology in PSP. Neurobiology of Aging. 2025. ↩︎
Gupta R, et al. Therapeutic targeting of brain insulin resistance in 4R-tauopathies. Nature Reviews Neurology. 2024. ↩︎