Gene Therapy Advances in Alzheimer's
Researchers are making progress on new treatments for Alzheimer's disease, with recent advances focused on gene therapy and targeting brain-derived neurotrophic factor (BDNF) and microglia. The work involves research teams at institutions including Harvard, UCSD, and UCSF. These developments are relevant for students tracking competitive and research-intensive specialties like neurology.
One key approach delivers Brain-Derived Neurotrophic Factor (BDNF) to the entorhinal cortex, a critical memory center in the brain. Preclinical studies in rodent and primate models of Alzheimer's showed that this method can protect neurons and improve learning and memory. The goal of using this growth factor is to rebuild and repair brain circuits after the disease has already caused damage. A first-in-human Phase 1 clinical trial, led by Dr. Mark H. Tuszynski at UC San Diego, is testing the safety and efficacy of this BDNF gene therapy (AAV2-BDNF). Early results from the first few patients have shown the treatment to be safe, with no serious adverse events. PET scans have also indicated an increase in cortical metabolism in the treated brain regions, which is a reversal of the typical decline seen in Alzheimer's patients. Another research angle focuses on microglia, the brain's immune cells. Scientists at UCSF, including Dr. Xianhua Piao, have identified a specific receptor on microglia called ADGRG1 that is essential for clearing the amyloid-beta plaques characteristic of Alzheimer's disease. In mouse models, the absence of this receptor led to a rapid buildup of these toxic plaques and associated cognitive decline. This discovery opens the door to developing drugs that could boost the effectiveness of microglia in all patients. Analysis of human brain tissue has shown that individuals who died with only mild Alzheimer's symptoms had microglia with high levels of the ADGRG1 receptor, suggesting its protective role. At UC Irvine, a team led by Mathew Blurton-Jones is engineering microglia to act as "living cellular couriers." Using CRISPR gene editing, they have programmed human microglia to produce an enzyme that breaks down amyloid-beta specifically in the vicinity of plaques. In mouse models, this approach reduced amyloid buildup, protected neurons, and curbed inflammation. Research from Harvard Medical School further supports the importance of BDNF, showing that while inducing the birth of new neurons can be beneficial, the presence of BDNF is crucial for their survival and for mimicking the cognitive benefits of exercise. This highlights the neuroprotective environment that these new gene therapies aim to create.
