For generations, Alzheimer's disease has been framed as a story of accumulation — proteins piling up until the mind dims. Now, a team of Italian researchers at the Catholic University of the Sacred Heart has turned attention toward a different chapter: the brain's own immune cells, which in chronic disease can become agents of destruction rather than protection. Using nanoparticles drawn from the human placenta and delivered through a nasal spray, they found that in mice engineered to develop Alzheimer's-like decline, six months of treatment quieted neuroinflammation, improved memory, and supp