November 3, 2019, Kevin R Stone in Silicon Valley Blog | Lifestyle

Yes, you can stream Netflix—and your body can stream stem cells. In fact, this is the up-to-the-minute thinking about how stem cells work. Here is the latest from the recent International Cartilage Repair Society meeting on stem cells, growth factors, bone marrow, fat, and PRP.

Turns out that stem cells—those ubiquitous, omnipotent, cure-all cells that the body has and that you desire—are far more complex than advertised. Yet they are simpler to use than many companies would like you to know.

Stem cell science has been around for a long time. We knew that, in the embryo, certain multipotent cells grew after the sperm and egg connected. They then differentiated into the various tissues and organs of the body. With maturation, the stem cells specialized in various tissues and organs such as bone, muscle, nerve, and blood vessels. The specialized cells are sometimes called progenitor cells. These cells then direct the ongoing maintenance of the body, responding in force to influence the repair process when injuries occur. The signals that call the body’s stem cells into action have been identified: They arise from a variety of proteins commonly called growth and chemotactic factors, now collectively called bioactive factors.

During the last ten years, concentrating stem cells from bone marrow, fat, and birth tissues—then injecting them into the sites of injury, osteoarthritis, or even normally aging tissues—has been all the rage. And they all work, to some degree. “Work” means that the patients feel better, the joints are less swollen, pain is reduced, and some tissues may actually heal faster after injury. Other than their cost, these injections had essentially no downside. And they were almost always far preferable to cortisone, which damages the tissues doctors are trying to heal.

What has now become clear is that the pathway all the beneficial effects had in common was the reduction of inflammation. While none of the injections was definitively proven to regrow any meaningful amount of tissue, all of them reduced inflammation, thereby helping patients to feel and perform better. But how did they accelerate healing?

The exciting data is that these injections of bioactive factors not only reduced inflammation and stimulated tissue healing, they also sent out a call to recruit the body’s own stem cells to the site of injury. So injecting a high concentration of bioactive factors—which then recruited the patient’s own stem/progenitor cells, which in turn drove the healing process—was the key therapeutic action. This is substantially different than trying to inject actual stem cells from another part of the body, or from a donor, since there simply is no way to compete with the volume and specificity of cells that the patient’s own body can generate.

One source of confusion right now is, where can we find the highest concentrations of the best growth factors? In independent testing of PRP (the most common blood concentrate), the variations of growth factors from the same patient at different times of the day were fivefold. There was no consistency of results between devices, nor from the same device tested on the same patient on their right or left arm. Fat and bone most likely suffer from the same variations, and older people most likely have less potency. Amniotic fluid—a birth tissue fluid—had 2-50 times the concentrations of most of the important growth factors (which makes sense, since nothing grows faster than a fetus). Many companies, however, are currently providing varying birth tissue products: some with amniotic membranes, some with Wharton’s Jelly (a gelatinous substance inside the umbilical cord), but all without sufficient documented biochemical profiles or FDA guidance.

It follows, then, that to best stream stem cells to the site of an injury or arthritis, our strategy should be to load the site with the clarions calling the repair sentinels: the proteins and bioactive factors known to recruit stem cells, and act independently to shut down inflammation and induce the natural healing process.

So save yourself the trouble and expense of injecting stem cells. And never spend time growing them outside the body. There are billions of stem cells within you—it just takes a little tickle, a wake up call, or sometimes a fire alarm to get them where they belong.

DISCLAIMER : Views expressed above are the author's own.

Dr Kevin R Stone is a pioneer of advanced orthopaedic surgical and rehabilitation techniques to repair, regenerate and replace damaged cartilage and ligaments.
The author was trained at Harvard University in internal medicine and orthopaedic surgery and at Stanford University in general surgery. He enjoys skiing, windsurfing, and biking.