Stem cells are the most important cells in our body because they work very hard and continuously rejuvenate our tissues. We are sometimes not aware about this very important fact, how stem cells are hard-working during our life. Just a few examples: the whole epithelium in the intestine is replaced every four days; our epidermis is replaced every two weeks and, as you know also, blood cells have a half-life and it is very hard work for stem cells. The number of the cells decreases with age and we can postulate that if we will be able to slow down this process, to keep the stem cells in good condition, then we will be living much longer and also we could improve the quality of our life. Since stem cells are so crucial in rejuvenating our tissues, our group is developing different strategies of how to keep them in the best condition during our life because we know the number of stem cells decreases with age. We could consider some pharmacological intervention to keep the cells in the best condition, calorie restriction and also it is very well known that it is a beneficial effect of exercise on longevity and quality of life. Actually we have, for the first time, demonstrated in animal models that continuous strenuous exercise, in the model mice were exercising in rotating wheels every day, has a beneficial effect on very primitive population of stem cells in our tissue, stem cells which are most primitive, like precursors for tissue-committed stem cells. We described these stem cells a couple of years ago and we called them VSEL, very small embryonic-like stem cells. These cells have a lot of features of embryonic stem cells, however are isolated from other tissues so there is not here any controversy about using cells from foetal organs. Such cells are deposited during development in other tissues and we have many data right now that these cells are like a mother for other, more differentiated tissue-committed stem cells, are playing a very important role in tissue organ rejuvenation. What we have demonstrated for the first time is that regular, strenuous exercise has a beneficial effect on the population of these very primitive cells.
How can you see the benefits in the cell?
We were looking at different aspects; we were looking for a number of the cells in the bone marrow and also other tissues. We were also evaluating gene expression in these cells which regulate primitive status, pluripotentiality of the cells, this means the ability of the cells to differentiate in different tissues. Also we have found that strenuous exercise also mobilises these cells into peripheral blood. These cells circulate, reach a different location in our body where they are playing a very important role in tissue organ rejuvenation. We were looking at both, we were looking at the most primitive, very small embryonic-like stem cells, VSELs, and we were also looking for other types of more differentiated cells like haematopoietic stem cells, mesenchymal stem cells and arterial progenitors. All these cells are mobilised during strenuous exercise but what is most important and novel in our research is that these most primitive stem cells, very small embryonic-like stem cells, VSELs, which are a founder for other tissue-committed stem cells, including haematopoietic stem cells, are preserved in the bone marrow with age if mice exercise and also they expand. For the first time we have explained at stem cell level a beneficial effect of exercising, jogging, strenuous exercise on quality of life, longevity and stem cell numbers in other tissues. Definitely there are several aspects in preventing cancer and preventing a lot of other disorders but also our research indicates that it is also beneficial directly in tissue organ rejuvenation. Since I mentioned at the beginning that we rejuvenate our tissues continuously during our life, but later on with age this process is somehow impaired. If we will exercise on a routine basis, we have a chance to live longer, be healthier and the best evidence is that we prevent these very primitive cells from premature depletion from our tissues.