Researchers at Johns Hopkins have grown small clumps of brain tissue, called organoids, from cells taken from people with Alzheimer’s disease. These mini‑brains may help doctors predict which medicines will work best for each patient.
The study used organoids that mimic the hindbrain, the part of the brain that controls breathing, sleep, and heart rate. By testing the antidepressant escitalopram on these organoids, the team could see how different patients might react to the drug.
To create the organoids, scientists first took blood from volunteers. They turned the blood cells back into stem‑like cells, which can become any type of cell in the body. These stem cells then grew into tiny, pea‑sized brain clusters that contain neurons that make serotonin, a brain chemical linked to mood.
When the researchers compared organoids from Alzheimer’s patients with those from healthy donors, they found clear molecular differences. Proteins that help brain cells talk to each other, control inflammation, and manage disease pathways were altered in the patient organoids.
After treating the organoids with escitalopram, some showed an increase in proteins that support serotonin signaling. Other organoids showed little or no change. This shows that even within the same disease, people can respond very differently to the same medicine.
While the organoids were growing, they released tiny particles called extracellular vesicles. These vesicles carry proteins and other cellular information. The scientists discovered that the vesicles from Alzheimer’s organoids had lower levels of proteins such as RAB3A, NSF, and ATCAY, which are important for normal brain communication.
When escitalopram was added, some vesicles showed higher amounts of proteins linked to serotonin and synapse function. This suggests that measuring vesicles could one day help doctors decide which patients will benefit from a particular drug.
Looking ahead, the team plans to make organoids more realistic by adding immune cells and tiny blood‑vessel‑like structures. If successful, the vesicles could serve as a “liquid biopsy,” a simple test that tells doctors how far Alzheimer’s has progressed and which treatments might work best.
This research is an early step toward personalized medicine for Alzheimer’s disease, offering hope for more accurate diagnoses and better‑targeted therapies.