It’s great when an idea like stem cells for osteoporosis just makes so much common sense, but it still requires data. A logical hypothesis is not enough. The point of today’s post is to fact-check the idea of using stem cells for such bone loss.
A femur to stand on?
Unfortunately, the take-home message is that there just isn’t enough data to support the use of stem cells for osteoporosis now. On the flip side, there aren’t data really refuting the idea either so this area is kind of in limbo.
Read on to learn what we do know and the key open questions as well as ongoing clinical trials.
What is osteoporosis?
Osteoporosis is a gradual loss of bone with aging to the point where fractures become likely.
While a relatively earlier problem for aging women, it happens to men too, just later.
Some people are more predisposed to osteoporosis, particularly those who are petite or have small bones to start with in life.
What causes osteoporosis?
The pathological mechanisms of osteoporosis have been studied intensively, but the key molecular and cellular events are not totally clear.
It seems part of the problem is with an imbalance in the two main types of bone cells. Osteoclasts eat or resorb bone, while osteoblasts make bone. Normally there’s an exquisite balance in their activities so bone is just kept in balance. You can imagine that too much bone from an excess of osteoblast activity could cause serious problems. You don’t want extra bone floating around or growing off in odd directions.
Conversely, too much osteoclast activity could lead to thin bones, which in a sense may be what’s happening in some forms of osteoporosis, possibly as a result of hormonal changes.
How is it prevented or treated?
One main way osteoporosis is treated is via drugs called bisphosphonates, which in part inhibit osteoclasts. In rare cases, these drugs can cause problems like bone death or osteonecrosis. Hence, researchers have been exploring new approaches to osteoporosis like stem cells.
For more info on bisphosphonates I have included a link to an information page from the American College of Rheumatology.
What about vitamin D supplementation? I’ve written before how vitamins in general have been a big disappointment, but an exception is vitamin D supplementation for osteoporosis. Talk to your doctor before taking any supplements.
Stem cells for osteoporosis: an idea but not a reality yet
Stem cells make so much sense in theory for osteoporosis because certain stem cells can readily make new bone.
If you can get the right stem cells in the right place (e.g., on vertebrae with thinning bone), they could potentially increase bone density.
The problem is that the idea just hasn’t yet been born out by data.
Unfortunately, many stem cell clinics around the world are already selling stem cells for bone loss despite the lack of data and trials. They are taking advantage of vulnerable patients.
Clinical trials
A clinicaltrials.gov search for stem cells for osteoporosis identified a dozen trials. However, most are not active. Only 2 are recruiting. The thrust of research in this area is focused on mesenchymal stem/stromal cells or MSCs, but several of these trials are not interventional studies using cells at all.
Specific kinds of MSCs can readily generate bone in the lab with specific differentiation protocols so there is some logic to testing them.
I found a review article from 2020 that listed 2 interventional trials of stem cells for osteoporosis, but neither had published data at that time and one was terminated. I’ve listed the article in the References section at the bottom of the post if you want to check it out.
Published data
What do the published data say more broadly?
I found more than 700 papers on stem cells for osteoporosis via a literature search on PubMed, but none were clinical trials. I might have missed some based on how I did the search so I tried other forms of the search but still found no published interventional trials. Some clinical work popped up but it was mainly related to bone marrow loss after hematopoietic stem cell transplantation such as during treatment for blood cancers.
On the web, I found a completed translational CIRM grant that studied the use of stem cells for osteoporosis in rodents. They reported some general data from animal models there so take a look.
Overall, given the negative impact of osteoporosis on human health and the logic behind the idea of trying cell therapy, I hope more clinical trials will be conducted soon. It’s also unfortunate that unproven clinics are already selling an unproven idea like this.
I’ll do an update in coming years if I see more developments. If you know of other clinical trials in this space please let me know and I’ll update this post.
References
- Info page on bisphosphonates from the American College of Rheumatology.
- PubMed search for papers on stem cells for osteoporosis.
- Clinicaltrials.gov search for trials for stem cells for osteoporosis.
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Advances in mesenchymal stem cell transplantation for the treatment of osteoporosis, Cell Proliferation, 2020.
Note that I am not a physician and this post is not meant as medical advice. Consult your physician when making medical decisions.
https://www.nature.com/articles/s43587-021-00105-8