The Two-Faced Story of Our Cells

Recently I took to exploring the emerging field of human longevity. Wild thoughts of humans living until 230 years of age, pumping strange chemicals into our bodies, going to school for 50 years, and other interesting notions ran through my head. Learning the difference between lifespan and healthspan was valuable information that I stumbled across that definitely piqued my interest. (Just in case you’re curious: lifespan refers to how long we live whereas healthspan refers to how long we are healthy and well, without diseases. In other words, we need to optimize for longer healthspans not necessarily longer lifespans). To be honest, I didn’t take the field very seriously. Claims made by researchers and companies seemed a little too optimistic. Vitamins, injections, maybe even human trials of different chemicals, proteins, and enzymes felt more theoretical and science-fiction worthy than a nearby, plausible reality.

However, when I watched Elizabeth Blackburn’s TED Talk: The Science of Cells that Never Get Old, my views started shifting. The artful exploration of Tetrahymena (pond scum) and the discovery of telomeres played a significant role in changing my mind. But it was the few short minutes in the middle of the talk when Blackburn mentioned trauma in conjunction with telomeres. Was my fascination truly set in motion?

A Brief (not so philosophical) Explanation of Life

Because of biology classes and health classes all throughout the country — and the world — I’m sure we’re all aware that there are thousands of biological processes that work in tandem to ensure that we are alive at this moment. I’ll be focusing on the simple mechanics of how it is that we are physically here today.

We all start the same: one cell. Just one tiny cell that eventually grows and develops into 200 million billion cells that make up the human body. But how do we get there? Well, that one cell doesn’t stay single for long. It divides, and then those cells divide, and then those cells divide, and the process keeps going. Eventually, those ever-multiplying cells specialize and form clumps that turn into organs. But it’s when we zoom in even further when the story gets interesting.

Although we all know the human body is an extremely complicated and nuanced piece of natural machinery, the cells add an extra layer of minute detail. Within cells lie our chromosomes which are essentially long DNA molecules located in the nucleus that carry our genetic instructions in the form of genes. Typically, everyone has 46 chromosomes, half from the mother and half from the father. The DNA is a double helix that is composed of four bases known as Adenine, Thymine, Cytosine, and Guanine in which Adenine and Thymine are always paired together and Cytosine and Guanine are always paired together. The different orders of these combinations create the genetic code that dictates every little part of us.

But when we zoom in even further to focus (I know we’re doing a lot of zooming here) on just the ends of chromosomes a whole new world unfurls. The tails of chromosomes are called telomeres which are essentially caps. They contain a repeating sequence of DNA that can reach a length of 15,000 base pairs. Why all the excess? Well, you see, it’s not actually excess. Our body’s cells don’t stop dividing, this is a repeating process that occurs every second of every day. As cells divide, the components within them divide as well: this includes chromosomes. Considering that chromosomes contain the blueprints of who we are, a change in one base pair throws off the whole sequence — changes who we are, fundamentally! To prevent such a catastrophe from occurring, telomeres prevent chromosomes from losing base pair sequences at the end. Every time the cell divides a little bit of the telomere shortens. When the cell can divide no longer it either becomes a senescence cell — one that doesn’t divide anymore — or goes into apoptosis — the cell dies.

But Who Cares?

This is the million-dollar question. Literally.

For this to make sense in the grand scheme of things we need to backtrack into the broader world of Human Longevity. Essentially, we humans live for an X amount of years, that X is of course variable to our environment, eating habits, exercise, race, etc. The issue is that for whatever number that X is, we spend all X years aging. Although it’s easy to file aging as a marketing tactic used to sell anti-wrinkling creams (which, make no mistake, it certainly is), aging is the number one cause of death. The fine lines, wrinkles, complaints about taxes are all just the visible signs of aging.

The inside of our body tells a different story. It helps to think of the body as machinery, perhaps a car (maybe a Tesla, go wild). Just as cars gain more miles and break down with gas leaks, plugged filters, rusting metals, etc. our body is also worn down by the number of bodily processes that occur. And although we are naturally equipped with mechanisms to cope with the daily wear and tear of being alive, as we get older these mechanisms to begin to get worn down too. Our bones weaken, our muscles hurt, somehow all the ads we see are anti-aging serums, and a barrage of other misfortunes. Essentially old age is a disease that paves way for more disease until the body is overloaded and simply starts shutting down.

So what does this have to do with telomeres? Well, one of the many bodily processes that play a role in aging is cell division. Eventually, our cells cannot multiply as quickly as before. Our telomeres get shorter and shorter until we see the inevitable “Game Over” sign. In other words, our telomeres exercise significant control over the span of our lives. Some researchers argue that the time we spend on this Earth is decided from the day we are born depending on our telomere lengths.

Telomeres Have a Partner in Crime

While telomeres represent the physical caps at the end of a chromosome, their function is largely determined by another quieter player. Telomerase is an enzyme that is in charge of replenishing the telomeres. That’s a bit confusing, I agree. Essentially, the story I told you before isn’t completely correct. Just like we can elongate the life of a car by taking it for routine checkups, oil changes, etc. our telomeres have a similar mechanism. Telomeres are accompanied by a personal helper: telomerase which is responsible for maintaining the length of telomeres. They help add on more base pairs and ensure that the telomere’s don’t shrink too much. While it may seem that we should be immortal because of telomerase, the enzyme doesn’t work that way. It too has a limit.

So Let’s Just Lengthen Telomeres Then. Problem Solved!

Unfortunately, it’s not that simple. After hundreds of years of evolution, the human body has created a system that lies in a precarious balance. Shifting any one thing too much can offset many other biological processes, becoming a critical danger rather than a solution. If we were to pump telomerase into the body in order to lengthen telomeres we could be jeopardizing the body for cancer. Despite being sound systems, introducing telomerase where it doesn’t actually exist could lead telomerase to target the wrong type of cells, allowing them to grow uncontrollably. It would keep enabling rapid cellular division which causes tumors and soon those tumors could start cannibalizing on other cells. An overabundance of telomerase lowers the body’s healthy regenerative potential in the body and thus we could accidentally cut down life rather than increase it.

Which likely begs the question: why are we looking towards telomeres for longevity research anyway? While longer telomeres have demonstrated that a person may live longer, it is not a perfect science. There have been a significant amount of studies that have demonstrated that people with longer telomeres face less risk for cardiovascular issues, etc. However, we must be cognizant of the fact that these samples are taken at very particular points of time and they also include confounding variables such as: environmental, genetic, history of the cell, etc. While telomeres may certainly hold the key to unlocking a longer health span, there is significant research that needs to be done to figure out how to perfectly optimize it. But, given how far we’ve come there is no denying that telomeres are critical to understanding the human body better.

Alright, now what?

Although it may feel like there’s nothing to come out of this research, that’s simply not true. In fact, we can use the information we have currently and make a significant difference in our lives while more information is conducted. Throughout this article, we’ve established that environmental factors take a significant toll on our bodies.

Being overwhelmed, toxically stressed, having unhealthy eating habits, etc. places a significant burden on the body. It’s similar to when there are obvious bugs in the code but expecting the program to run smoothly anyway. The human body has a sweet point where it efficiently functions and when we are forced to reckon with these outside factors as well, our body doesn’t always do well in accounting for them. To maintain function we need to sacrifice something.

Of course, it’s ok to be stressed every once in a while, reach for chips when deadlines are approaching, or having periods of time when there’s too much on your plate. However, today’s grind culture forces us to believe those behaviors are normal. The more you do the better you are. All of this weight has a significant toll on the body. These unhealthy habits can expose you to autoimmune diseases or other health issues. And what happens when your body faces a disease, it impacts you on a cellular level — your cells are unhealthy too. To combat that, the body starts dividing those cells more quickly because it is trying to help you recover, increasing the shortening of your telomeres rapidly, causing premature cellular aging.

Everything that occurs in our body is interrelated. Every process, whether we realize it or not, is connected to another biological process that allows us to survive. In some ways, it’s very much akin to a teenager’s messy room. Everything is precariously balanced and rather difficult to make sense of, but moving one little thing suddenly changes the entire room: clothes fly everywhere, books fall down, plates are crashing, etc. We may not be able to meddle with our telomeres and telomerase production until scientists have made further progress but until then we need to handle our bodies the way we deal with teenagers’ rooms: with care and empathy.

Making healthy choices in terms of diet, physical activity, how we expend our mental energy, who we surround ourselves with, the pollution we are exposed to, etc. all come together and leave significant impacts on our bodies. This impact can either be overwhelmingly positive or negative. Of course, not everything is within our control, sometimes our circumstances leave us without options. However, mitigating what is in our sphere of control is critical to ensuring that we are increasing our health span, or at the very least maintaining it.