Two Landmark Studies Challenge Dogma About our Brain Immune Cells and Aging

This podcast is meant to complement my recent Ground Truths post Why Our Memory Slips After Age 50 which has all the relevant links to the 2 papers, key graphics, and other related publications. If you haven’t had a chance to read that, it would be helpful to spend a few minutes to do so before listening to this podcast.

Links to the 2 papers for those who don’t want to look back

Zemke et al in Science https://www.science.org/doi/10.1126/science.adt8307

Belk et al in Nature https://www.nature.com/articles/s41586-026-10939-0

It’s a major and fascinating discovery. We’re talking about a “hostile takeover” of blood monocyte cells that invade the brain and ultimately completely replace the brain microglia. The problem is these new microglia are pro-inflammatory.

A surprising finding is about CHIP (blood stem cells with mutations known as clonal hematopoiesis of indeterminate potential) that was shown to be protective. It’s surprising because CHIP is common with age and until now it has been linked to bad things such as cardiovascular disease, clotting, and cancer. If this pans out, it introduces the concept of immunotherapy of the blood (“brain immunotherapy”).

We discussed recent studies of microglia replacement and ways to keep our brain microglia intact, such as prevention any breakdown of the blood brain barrier.

The role of latent viruses and the mechanism of benefit of the Shingles vaccine were touched on.

Our conversation provides far more color and perspective about why their independent, complementary, and convergent findings are so important, debunking our longstanding belief that the microglia, the immune cells in the brain, are exclusively derived from the brain. Technology driven discovery. And what are the next steps in this line of research.

I hope you found this podcast illuminating and fun. If you did, plus share it with your network. Thanks for supporting Ground Truths and your help in spreading the word.

And thank to jojofinance, Elisabetta Pilotti, Daniel Rench, Dr. Sara Wolfson, Bob Fleischman, and hundreds of others for tuning into the live video with Julia Belk and Nathan Zemke! Join me for my next live video in the app.