One Dirty Magazine

Stem the Joint-Aging Tide

Is stem-cell treatment right for you?

Beth Bennett January 17th, 2019

Stem the Joint-Aging Tide Photo by Guillem Casanova Bosch

Trail running is one of the best ways to stave off the effects of aging. It keeps our cardiovascular systems young, our brains healthy and it even keeps cartilage intact. And yet, according to the Arthritis Foundation, over half of us will experience some age-related joint degeneration, like osteoarthritis, during our lives.

Osteoarthritis is the loss of the protective cushions of cartilage in joints like the knee. Once cartilage is damaged, it gets inflamed, which causes more damage and a painful cycle ensues. Previous injuries as well as a history of running hard and long can also increase your chances of developing arthritis.

Treatments like physical therapy, anti-inflammatory drugs or steroids can keep a lot of runners going, but there is no specific cure. Eventually, many people choose to have a joint replacement to escape the bone-on-bone pain.

This is one reason stem-cell treatments don’t work equally well for everyone. Growth factors and other essential ingredients may not be present in adequate amounts in different preparations.

Since about 2010, a different, non-surgical option has come onto the scene with much intrigue: stem-cell injections.

Stem cells are the building blocks our bodies use to build and repair all of our tissues—muscles, bones, even nerves.

How Do Stem Cells Work?

Cuts, abrasions, fractures, tears and stresses send a signal into your blood calling for help. The first step in the healing process is to get more blood flow to the area. This brings immune cells to pick off any bacteria that may have sneaked in. The immune cells also signal local stem cells to begin dividing to make more cells that will fill in the holes. In just a day or so, these little cell factories scab over the scrapes and grow new skin.

Shirley G, an avid hiker and biker, says the pain in her knees was so bad she could barely walk. After several bone-marrow MSC injections, she said, ‘I got my knees back!’

Almost every tissue in an adult body has its own type of stem cell for repairing itself; however, as we get older, we have fewer of them and they don’t work as well. So, just shoot some more into an arthritic joint, right? Not quite.

The repair process requires a specific set of signals. Like when baking cookies, you have to add specific ingredients (stem cells and growth factors as well as other things, typically proteins), in a certain sequence or else they’ll turn out like sad pancakes.

When stem cells are injected, all of the required signals need to be in place in the right order. If everything is a go, the stem cells will divide to produce more cartilage (or whatever tissue is needed). Figuring out which signals are used in which tissues is a big research area right now, but it’s not well understood.

This is one reason stem-cell treatments don’t work equally well for everyone. Growth factors and other essential ingredients may not be present in adequate amounts in different preparations.

What Kinds Are Available?

There are two types of stem cells that can be used in treatments: MSC (Mesenchymal stromal cell, an adult stem cell, producing bone, cartilage, muscle, fat and a few other cell types) and FS (Fetal stem cell, producing almost all types of adult cells).

The FS stem cells are found in amniotic fluid, umbilical cords and in placentas. As you may know, these tissues are produced by a growing fetus. You may not know that there is a developing industry in obtaining, harvesting and selling these stem cells—mostly from placentas.

MSC are pre-specialized to divide into cartilage-producing cells and can come from bone marrow or be purified from fat. In fact, it’s become popular to go in for liposuction and pull out MSC.

MSC living in fat don’t have the same environmental triggers for developing into cartilage as those in bone marrow; however, getting the cells from fat is a lot less painful than sticking a giant needle into your hip bone.

There are about 50 published studies following osteoarthritis patients injected with these two types of MSC. The results were all good when patients were compared with untreated controls, but all of the studies had pretty small samples and short follow-ups. Bottom line: some of the good outcomes could be due to placebo, and others might wear off. It’s unknown at this point.

Nonetheless, this is sounding promising right?

U.S. versus Abroad

Bone marrow is probably a better source of MSC if we want to stack the deck for stem cells to grow into cartilage. The bad news is that you don’t get that many cells from an aspiration of the hip—maybe 10,000 to 100,000. Although this sounds like a lot, you can get a lot more from placentas. In clinical trials, most of which have been done outside the U.S., the MSC are put into test tubes and grown in a lab for a few weeks. Then the cell count goes way up, into the millions. One of the findings of the clinical trials is, the more stem cells you put in, the better results you get.

But it gets trickier. Even though the bone marrow pulled from a hip has a lot of MSC, it also contains other types of stem cells. Some tricks have to be used to pick out just the MSC before they are injected.

In the U.S., the FDA restricts what clinics can do with stem cells. When the cells are withdrawn, they can only be “minimally manipulated” and must be re-injected in the same day. This means the bone marrow can be centrifuged to pull out the stem cells but not grown for weeks or treated to isolate the MSC. What’s more, the injected cells are supposed to have the same basic function as the tissue into which they are being injected. One example of this would be a cornea transplant. This equivalency is really hard to define for stem cells because they can grow into so many other types of cells.

Not surprisingly, there are a lot of gray areas in these regulations. This ambiguity allowed explosive growth in the number of stem-cell clinics in recent years. In the past few months, however, the FDA has been more aggressive about shutting down clinics with egregious violations.

To Inject or Not to Inject?

Stem-cell therapy is promising, but, like other treatments, it has certain risks. Educate yourself and ask the relevant questions of any stem-cell-therapy provider.

There is also a lot of anecdotal evidence—on both sides.

Personally, if I had the money for a European stem-cell vacation, I might go for it. The methods used there for concentrating cells—which give you a better chance for a good outcome—are just not available in clinics in the U.S.

I spoke with several athletes (who were reluctant to use their full names) who went to local clinics for stem-cell injections into their knees. Shirley G, an avid hiker and biker, says the pain in her knees was so bad she could barely walk. After several bone-marrow MSC injections, she said, “I got my knees back!”

Anne B had to give up running due to osteoarthritis. She says, “My knees have improved significantly, but I don’t know if it was the stem cells, the PT or the alignment work.”

Finally, be aware that there are changes in the works at the FDA. This spring, they released a statement saying they will start to “expedite” the regulatory process. But, no further changes have been made at this time.

Current FDA stem-cell guidelines:⁄guidancecomplianceregulatoryinformation/guidances/cellularandgenetherapy/ucm585403.pdf

Beth Bennett has her Ph.D. in genetics and taught biochemistry physiology at the University of Colorado for 25 years.

This article originally appeared in the December issue of Trail Runner. To get quality content like this delivered right to your door, click here.


Leave A Comment

6 Comment threads
1 Thread replies
Most reacted comment
Hottest comment thread
7 Comment authors
Doug KKeith AurandRichNancy KurtzMarty C. Recent comment authors
newest oldest most voted
David A.

I had fetal stem cell treatment in June during the middle of marathon season training. (The doctors recommend against this.) The pain had gotten so bad during downhill running that I had to drop trail running all together. My knee would swell up for days after a minimal trail run. I couldn’t even walk through a grocery store without swelling. In October, I ran a BQ and PR on a downhill course with absolutely no knee pain and haven’t had pain since. The procedure was expensive, but worth every penny.

Carroll Bush
Carroll Bush

Beth/TR Mag, I have been researching stem cell treatment for a few months now due to an osteoarthritic knee . I am also intrigued and interested in PRP (platelet-rich plasma) injections. What is your thought on this treatment and how does it compared to stem cell treatments?

Thank you for and response and information you may provide.

C.J. Bush

Marty C.
Marty C.

I am all for stem cell treatment or plasma rich platelet injections (not sure what the difference is), but all doctors I have talked to have told me that no insurance company will cover the cost. My understanding is that it is ~$3,000-$5,000 in cost. Not sure how feasible that is for the non-sponsored, “average Joe” runner.

Nancy Kurtz
Nancy Kurtz

Not mentioned in this article is the cost of Stem Cell therapy. When I asked about getting stem cell injections I was told that since it is still considered experimental it is not covered by insurance. The cost is thousands of dollars.


I had PRP Platlet rich Plasma done on 10/1/2018. So far my knee has responded well. PRP the doc drew my own blood spun it down and injected my own platlets and plasma. PT is going on now. I’ve been running a mile at a time slowly getting back to the running I want to do. Keeping my fingers crossed.

Keith Aurand
Keith Aurand

Can you be more specific on what the risks are?

Doug K
Doug K

according to this review article, ” risk of complications after surgery, compatibility of donor stem cells” There really isn’t any hard evidence one way or the other on stem cells for knee arthritis. There is a clinical trial ongoing now, but it’s just in the recruiting phase, and is sponsored by one of the drug companies. Another clinical trial sponsored by a company in Italy, and (same study but different reports). It’s not complete yet either, supposedly midsummer this year. I may yet be desperate enough to try it.. if it works I don’t care if… Read more »


HELP US KEEP OUR WEBSITE FREE is completely free. We don’t have a paywall and you don’t have to be a member to access thousands of articles, photos and videos. Our editorial and design team—and all of our contributors—are trail runners just like you who love the sport and want to share all the great things it has to offer. 

But we can’t do it without you. Your support is critical for keeping our website free and delivering the most current news, the most in-depth stories and the best photography in the running world.

For 20 years Trail Runner has committed to excellence and authenticity. Your subscription to our print magazine or donation will help us continue down a path that is uncompromised, and keep the website free for trail runners like you.