Cerebrospinal Fluid From Young Mice Improves the Memories of Old Mice

(p. D3) Five years ago, Tal Iram, a young neuroscientist at Stanford University, approached her supervisor with a daring proposal: She wanted to extract fluid from the brain cavities of young mice and to infuse it into the brains of older mice, testing whether the transfers could rejuvenate the aging rodents.

. . .

Dr. Iram persevered, working for a year just to figure out how to collect the colorless liquid from mice. On Wednesday [May 11, 2022], she reported the tantalizing results in the journal Nature: A week of infusions of young cerebrospinal fluid improved the memories of older mice.

. . .

Cerebrospinal fluid made for a logical target for researchers interested in aging. It nourishes brain cells, and its composition changes with age. Unlike blood, the fluid sits close to the brain.

But for years, scientists saw the fluid largely as a way of recording changes associated with aging, rather than countering its effects. Tests of cerebrospinal fluid, for example, have helped to identify levels of abnormal proteins in patients with significant memory loss who went on to develop Alzheimer’s disease.

. . .

“This is a very cool study that looks scientifically solid to me,” said Matt Kaeberlein, a biologist who studies aging at the University of Washington and was not involved in the research. “This adds to the growing body of evidence that it’s possible, perhaps surprisingly easy, to restore function in aged tissues by targeting the mechanisms of biological aging.”

Dr. Iram tried to determine how the young cerebrospinal fluid was helping to preserve memory by analyzing the hippocampus, a portion of the brain dedicated to memory formation and storage. Treating the old mice with the fluid, she found, had a strong effect on cells that act as precursors to oligodendrocytes, which produce layers of fat known as myelin that insulate nerve fibers and ensure strong signal connections between neurons.

The authors of the study homed in on a particular protein in the young cerebrospinal fluid that appeared involved in setting off the chain of events that led to stronger nerve insulation. Known as fibroblast growth factor 17, or FGF17, the protein could be infused into older cerebrospinal fluid and could partially replicate the effects of young fluid, the study found.

Even more strikingly, blocking the protein in young mice appeared to impair their brain function, offering stronger evidence that FGF17 affects cognition and changes with age.

. . .

But Dr. Wyss-Coray said that the study filled a critical gap in the understanding of how the brain’s environment changes as people age.

“The question is, ‘How can you maintain cognitive health until you die? How can you make the brain resilient to this relentless degeneration of the body?’” he said, “and what a growing number of studies show is that as we learn more about the aging process itself, maybe we can slow down aspects of aging and maintain tissue integrity or even rejuvenate tissues.”

For the full story, see:

Benjamin Mueller. “A Step Toward Refreshing Memory.” The New York Times (Tuesday, May 17, 2022): D3.

(Note: ellipses, and bracketed date, added.)

(Note: the online version of the story has the date May 11, 2022, and has the title “Spinal Fluid From Young Mice Sharpened Memories of Older Rodents.”)

The academic article in Nature that reports the results discussed in the passages quoted above is:

Iram, Tal, Fabian Kern, Achint Kaur, Saket Myneni, Allison R. Morningstar, Heather Shin, Miguel A. Garcia, Lakshmi Yerra, Robert Palovics, Andrew C. Yang, Oliver Hahn, Nannan Lu, Steven R. Shuken, Michael S. Haney, Benoit Lehallier, Manasi Iyer, Jian Luo, Henrik Zetterberg, Andreas Keller, J. Bradley Zuchero, and Tony Wyss-Coray. “Young CSF Restores Oligodendrogenesis and Memory in Aged Mice Via Fgf17.” Nature 605, no. 7910 (May 19, 2022): 509-15.

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