Researchers Alter Blood Cells to Combat Alzheimer's and Aging in the Brain

In a groundbreaking study published in the journal Advanced Science, scientists at Cedars-Sinai Medical Center have developed a novel approach to rejuvenate young immune cells using induced pluripotent stem cells (iPSCs). These rejuvenated cells, named iMPs (induced Mononuclear Phagocytes), have shown promise in sharpening memory, calming brain inflammation, and making neurons look younger in mice with Alzheimer's disease.

The iMPs, acting like "janitors," clean debris from the body and fight infection, but can become less effective over time. This new method offers a potential solution to this issue, as it creates fresh batches of youthful iMPs.

In the study, the researchers injected iMPs into the animals' veins over three weeks, and the cells lodged in peripheral organs like the lungs and spleen. The treated mice recognized objects and remembered spatial layouts almost as well as youthful mice, indicating improved cognitive function.

When the researchers peered inside the hippocampus, they saw rejuvenated mossy cells - neurons critical for encoding new experiences. The treated mice performed better on memory tests, especially those requiring the hippocampus, the brain's memory hub.

Some of the genetic signatures of aging seemed to be disappearing in the treated mice. However, it's important to note that this research was conducted on mice, not humans. Clinical translation will require years of safety studies, careful dosing trials, and ethical oversight.

Tamping down inflammation and protecting neurons may be just as important in Alzheimer's treatment as sweeping away amyloid, the classic Alzheimer's plaques. Interestingly, iMPs did not reduce the classic Alzheimer's plaques, suggesting that Alzheimer's damage is about more than just plaques.

Previous studies using blood or plasma transfusions from young mice to treat cognitive decline in older mice have been difficult to translate into a therapy due to ethical issues and scalability problems. This new method, using iPSCs to create iMPs, could potentially overcome these challenges.

The implications of the study are vast, especially in the field of dementia therapy, where a new, radically different approach could be transformative. This method could pave the way for a new era in Alzheimer's disease treatment, where rejuvenation isn't just a metaphor; with the right kind of engineered cells, an old brain can act young again, at least in mice.