Jason Pontin: Why is cell turnover so important? Why do we care about cell turnover at all?
Doug Cole: Cell turnover is one of the most ubiquitous and fundamental features of biological systems. In every biological system cells are turning over constantly. And how they turn over has a lot to do with whether the individual is healthy or is not healthy. And so it's really critical if we are to understand fully what sustains the health of the individual and the circumstances in which disease emerges. It's essential that we understand cell turnover.
JP: If we define cell turnover more broadly to be what Inzen is calling Thanokine Biology, what functions do these signals perform in the human body?
DC: Maybe a good way to understand this is to put oneself, if you can, in the position of a cell in the body. You realize that that cell is living in a particular neighborhood—a micro-environment is the word that people are using scientifically now—and it's intuitive to expect that the cells success at sensing those inputs and reacting to them in appropriate ways might be essential to its ability to thrive as its micro-environment changes. And with that in mind, one can ask, well, what are what are the factors that contribute to that microenvironment?
One of them is very obvious: other living cells. Every every cell is surrounded by other living cells. And we know that living cells signal to other living cells all the time. We think of that kind of information as what the endocrine system does; where the signals arise from distant regions; what paracrine signals are; which are cells that arise from cells that are right next to signals that arise from cells that are right next to each other. We think of cytokines, which are a very important type of signals. They come from the immune system and so on. So living cells are well recognized as an important cell source of inputs to other living cells.
Another important source, of course, is the environment itself. What the individual consumes through through diet, what the individual is exposed to through the air and other environmental sources, which can benefit a particular cell or can harm a particular cell. And so, again, how a cell processes these inputs is critical to the phenotype and the status of that cell.
