Humans, Salamanders, and the Ability of Cartilage to Heal

Get a load of this: a scientific study is confirming that cartilage does have the capacity to regrow. Hooray!

Of course some of us have believed that for a while.

The reporting on this discovery has a kind of breathless tone of disbelief. The researchers who did the study call this ability we possess a “salamander-like” regenerative capacity. Salamanders, of course, can regrow limbs and parts of major organs.

As I’ve said a number of times, at least two studies done a decade or so ago have discovered that deep holes in cartilage can fill in naturally, at least part of the way, over a few years.  (For more, see here and here.) That doesn’t surprise me at all.

From an evolutionary biology standpoint, it just makes sense.

The cartilage in our knees takes a banging over the course of decades. It’s hard to believe that it would be designed so that it just wears out, like the tread on an overused car tire. Cartilage should have some natural regenerative capacity. Indeed, evidence has been found that, when damaged, it does try to repair itself.

The problem is, cartilage changes slowly. Defects in the tissue can easily get worse if too much pressure is applied to the knee joint. So getting better isn’t quick, or easy.

Anyway, more details on the study:

Researchers at Duke Health found that molecules called microRNA oversee the regeneration process. These molecules are more active in animals that are known to efficiently mend their own damaged limbs or fins, such as salamanders or zebrafish.

The research team thinks the microRNA could be used in treatments that could possibly reverse arthritis.

By the way, the researchers also looked at the age of cartilage in different locations in the body. It happens to be “young” in the ankle, “middle-aged” in the knee, and “old” in the hip. That, they suggest, could be why arthritis occurs more often in hips and knees.

So there you go. As you focus on gentle, low-load movement to heal your knees, you may be awakening your inner salamander!