HIF1A and Alzheimer disease: However, by 9 months of age, a sharp decline in HIF-1α and mTOR activity was observed, indicative of an immune-suppressed state resembling the chronic phase described by Baik et al. In this context, PDCs treatment successfully restored mTOR-HIF-1α signaling, leading to improved microglial function and neuroprotection in advanced-stage AD [306].