As I was sitting in my room about a week ago, I reach a rather startling conclusion about the real cause of the senescence of the growth plates. It has to be because of some elementary physics principle.

And what could that elementary physics principle be? I would guess that it is not just one elementary physics principle but from a few.

If we remember what I talked about in a previous post about the aging process of the entire human body, the theory was that it was not just telomere shortening that lead to agin  but also the work of free radicals in the environment around us. Free radicals are just molecules or atoms that have a single electron in the cloud instead of the needed, more stable 2 (or sometimes 8) full electron band. When you have molecules that have 1 missing electron, they will try to react with any possible other molecule or atom to collect the extra electron to satisfy the rule which was derived years ago by Pauli.

If one have ever taken a biotechology course before, they would have heard that nearly every part of our bodies function can eventually be reduced down and explained through either genetics, evolution and the need to adapt to one’s surroundings, or physics principles. If one really tired to understand what it is that allows us to hear and how the ears really word, we would realize that the vibrations of the ear hairs in the canal as well as the slight tremors the ear drum receives both send signals to a certain lobe in the brain to process. The air hairs and how they vibrate the the ear drums and how they vibrate can both be easily described from using basic physics principles learned of oscillators, vibration, frequency, and resonance.

Since free radicals are produced all the time all around us, it is inevitable that we would get old, just from statistical mechanics and randomness. The current theory for the free radical idea is that the free radicals get into the energy centers of our cells, the mitochondria and disrupt the mitochondria dna replicating process somehow.

I didn’t know that our growth plates went through senescence too, but only until may be a few weeks ago when I was sold of the phenomena by tyler. I always thought that after a certain point, when we the near end of puberty, the thyroid glands in our body decide once more to release a large set of Estrogens towards our estrogen receptors on our growth plates and tell them to increase the rate which chondrocytical apoptosis happens.

I guess just like senescence in general, the process of growth plate senescence is caused by more than one phenomena. Tyler did state in a post I put up today that “”Estrogen and it’s receptors are highly inefficient targets even though they are involved in height growth. Estrogen receptors have different effects based on differentiation stage and in gender””. So even if we did find a way to block the estrogens from binding to the receptor or inhibiting the release of estrogen or inhibiting the aromatization of testosterone, the growth plates will still start to disappear.

So the real question at this point is this, “If there is no estrogen to cause the growth plates to close, what is the other main cause that lead to growth plates senescence?”

My guess is that it is from a simple principle of physics, which is that the growth plates are having reached a threshold on their loading capacity. In general, the relation of a human’s weight and height is correlated but not linearly, As a person increase in height , their weight increases more in a faster rate path. Once the human have reached a certain height, the weight exerts a certain amount of force/area on the growth plates, which are only cartilage which is elastic. The cartilage being pushed at such a high level may cause the ossification and calcification layer to slowly over time creep into and overtake the hypertrophic layer, mainly due to the effects of the downward force of gravity. Of course we have to remember that the cartilage are not that weak. If it was that weak, humans would lose their ability to walk because the cartilage would break or slip. The effect would have to be very slow and gradual. This gradual process will eventually speed up with the estrogen flooding in around the end of the puberty stage.

Remember that people who are obese or overweight earlier in life tend to become shorter than their counter parts who are not. That would kind of back up this claim that more weight and more loading on the still existent growth plates will lead to the senescence of the growth plates to be faster.

I remember once watching this conference for people who were trying to slow down or even reverse the aging process and the main host and speaker stated that the real reason for aging was calcium. Calcification was the real cause for the multiple symptoms we see in people late in life. That was his claim. So it could also be that the loading is also helped out by the fact that over time, more and more calcium starts to seep into the cartilage and the calcium being crystals can act as seeds which germinate and have other calcium crystals develop around it as a form of calcium build-up.

Of course the next question to ask is this, “Why is it then that some people or ethnicities than have growth plates that can withstand more loading per square area than others?”

That may be due the fact that the growth plates can stay around longer if they get the right amount of nutrients to them to keep the proteins, collagen, and proteoglycans healthy enough. Note that calcium and vitamin D does indeed make bone density increase and make bones stronger. The glucosamine and chondroitin seem to help decrease the rate of articular cartilage lose at the long bones ends from a few studies.

Getting the right nutrients through food which have shown to help the density and strength of cartilage should be able to extend the cartilage slightly longer. This is the diet and nutrients factor, which explains why the asian countries which have been traditionally of short stature are now increasing in height from better food and nutrients. Besides that the only other factor would the person’s genes and the controlling signals Some people probably have genes that can create stronger and more resilient chondrocytes and collagen than others. Some people have genes that allow for more calcium and vitamin buildup in the bones than others. Some people have less estrogen receptors in their growth plates than others. And other people have more GH receptors in their Liver which leads to more IGF-1 production.

The senecence of growth plates can also be controlled by genes, but I would guess the main trigger for their senescence is the amount of loading that is over time exerted on them from teh increased height and wieght of the growing individual. Of course, this is just an idea and theory I came up with which can be totally wrong.