Wyss-Coray, from Stanford University, found that stitching together young and old mice to join their blood systems improved the older mice’s cognition. Startups began offering unproven “fountain of youth” blood-plasma infusions, but Wyss-Coray co-founded a company, Alkahest, to scientifically test the idea in people with early Alzheimer’s. Encouraged by early results, he now hopes to refine a blood-plasma treatment for aging brains. —Alice Park
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