Is There a Way to Protect Stem Cell Loss as We Age?

By /

The Fountain of Youth dates back to the time of the Greeks and then to the Spanish conquistadors who searched the Caribbean for the mythical place where the water of life would reverse aging. These days our search has turned inward, where we look for chemical or cellular pathways to stop or reverse cell aging or loss. One such study was just published that focused on reducing the natural loss of stem cells as we age. As a physician, perhaps the most exciting thing about the research is that it used an already existing medication that was discovered in bacteria on Easter Island. Let me explain.

How Stem Cells Work  

When the cells in your body become damaged, they are replaced by local stem cells that live in that tissue. For example, if a cartilage cell in the knee is dying, a stem or progenitor cell that lives next door will detect it and begin the steps to replace the sick cell. This is called differentiation. How does this work?

First, an adult stem cell nearby gets wind of a chemical signal released by the dying cell. The stem cell then makes two copies of itself; one cell will be kept in reserve for future use (replacing the stem cell being used for the repair job), and the other cell will replace the dying cell (this is called a progenitor cell). The progenitor cell receives many local clues from the surrounding cells, including the type of forces present (compression, stretching, sliding, etc.), the chemicals in the environment (inflammatory, pro-growth, status quo, etc.), and the cell type that surrounds it. Those signals transform the progenitor cells into the exact cell type that needs to be replaced. When the repair job is complete, remember that we still have one stem cell in reserve. This cell then goes into wait-and-see mode, waiting to spring into action at a future date when more damage is detected. Watch the video below to see visuals of this process.

When this fine balance between cell death or damage and differentiation is disrupted, problems can ensue. Unfortunately, even just the natural process of aging causes stem cells to die off and decreases their ability to regenerate damaged tissues. And one of those keys to the process of aging is found in the mTOR pathway

Join us for a free Regenexx webinar.

Defining the mTOR Pathway and Rapamycin

Mammalian target of rapamycin (mTOR) is quite a mouthful, but what you need to understand is that mTOR is a large protein that promotes and regulates the growth of cells, and it is a key pathway to the process of aging. Problems with the mTOR pathway have been associated with a variety of diseases, including diabetes and genetic disorders, and it is extensively studied in seeking treatments for cancer. The new study also suggests that repeated, or chronic, activation of that mTOR pathway as we age may be responsible for stem cell loss.

Rapamycin is now an immunosuppressant drug, which means it prevents the immune system from doing its job. While Ponce de León was searching for the water of life in Bimini, rapamycin was being produced by bacteria on Easter Island (halfway across the world)! In fact, the compound, which was discovered in a 1972 expedition, was named after the native name of the island, which was Rapa Nui. So maybe all of those big statues were trying to tell us something!

Why would we want to inhibit the immune system? Rapamycin is commonly prescribed following organ transplants, for example, so the immune system doesn’t target the donor organ as a foreign invader and attack it. Autoimmune conditions, such as Hashimoto’s thyroiditis and rheumatoid arthritis, are other examples where immune suppression might be beneficial depending on the severity. Rapamycin is also sometimes used, more controversially, on drug-eluting stents, which are devices that support a vessel that has been dilated to improve blood flow.

Now the new study suggests that rapamycin may not only prevent but also reverse stem cell loss caused by the mTOR pathway as we age. Let’s review.

Rapamycin May Prevent Stem Cell Loss as We Age

The new study consisted of mice (flies were also used) that were the human equivalent of 50 years old or older, all of which had experienced a decline in stem cell counts. The mice were treated with the drug rapamycin, and in all cases, the stem cell counts recovered. Researchers determined the rapamycin reversed the loss of stem cells in the aging mice (specifically in the muscle and trachea, as well as in the intestines of the flies). How? They concluded that the prevention of stem cell loss can be accomplished by inhibiting or blocking the repeated activation of mTOR signaling that occurs with age or injury, and rapamycin treatment was the vehicle that accomplished this.

Join us for a free Regenexx webinar.

Does This Mean I Should Be Taking Rapamycin to Protect My Stem Cells?

No, you shouldn’t be taking rapamycin to protect stem cells or slow aging. Despite the promising findings in the study, this doesn’t mean we should all rush out and get prescriptions for rapamycin. While this study may be the first of more to come to attempt to find additional solutions for stem cell loss in humans as we age, rapamycin is riddled with side effects that would likely negate its benefit to stem cells. Most of us, for example, wouldn’t want the harmful effects that would go along with blocking our immune system from doing its job.

The upshot? What’s really fascinating about this study is that it involves an existing drug. Also that it may be possible to find other ways to inhibit the mTOR pathway that are nontoxic and have fewer side effects. While Ponce de León, the Spanish governor of Puerto Rico, was searching the Caribbean for the Fountain of Youth, turns out it may have actually been located where all of those giant statues guarded the shore of an obscure island in Polynesia!

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile

If you have questions or comments about this blog post, please email us at [email protected]m

NOTE: This blog post provides general information to help the reader better understand regenerative medicine, musculoskeletal health, and related subjects. All content provided in this blog, website, or any linked materials, including text, graphics, images, patient profiles, outcomes, and information, are not intended and should not be considered or used as a substitute for medical advice, diagnosis, or treatment. Please always consult with a professional and certified healthcare provider to discuss if a treatment is right for you.

Get Blog Updates by Email

By submitting the form, you are agreeing that you read and consent to our Privacy Policy. We may also contact you via email, phone, and other electronic means to communicate information about our products and services. We do not sell, or share your information to third party vendors.

Category: Latest News
Copyright © Regenexx 2021. All rights reserved.



9035 Wadsworth Pkwy #1000
Westminster, CO 80021


*DISCLAIMER: Like all medical procedures, Regenexx® Procedures have a success and failure rate. Patient reviews and testimonials on this site should not be interpreted as a statement on the effectiveness of our treatments for anyone else.

Providers listed on the Regenexx website are for informational purposes only and are not a recommendation from Regenexx for a specific provider or a guarantee of the outcome of any treatment you receive.