Using tiny brainlike structures grown in a lab dish, researchers have found new evidence that a common virus responsible for cold sores might also be a cause of Alzheimer’s disease, according to STAT. The scientists reprogrammed human skin cells into neurons, grew them into 3D structures, and then infected them with the herpes simplex virus HSV-1. The cells produced buildups of the protein beta amyloid similar to plaques seen in the brains of people with Alzheimer’s, the team reports this week in Science Advances. The cells also mimicked the disease in other ways, showing signs of increased inflammation and reduced electrical signaling. The finding bolsters the theory that exposure to certain microbes could trigger Alzheimer’s—an idea supported by other studies finding viral genes in the brains of Alzheimer’s patients after death. But given that HSV1 infections are very common, it remains a mystery why the virus might trigger the disease only in certain brains.
