The results were presented at a press conference during the annual meeting of the American Society of Hematology (ASH) held on 8-11 December in Atlanta (Georgia).

"The indirect beneficial effect of physical activity on life expectancy has been known for a long time. Those physically active are definitely healthier. And certainly there is a relationship between regular exercise and the length and quality of life. However, we were the first to show that exercise stimulated reproduction of developmentally early stem cells responsible for tissue and organ rejuvenation in the adult body" - said in an interview with PAP lead study author Prof. Mariusz Z. Ratajczak, head of the Stem Cell Institute at James Graham Brown Cancer Center, University of Louisville and the Department of Physiology at the Pomeranian Medical University in Szczecin.

These cells, present in the bone marrow, are referred to in short as VSELs. "We call them very small embryonic-like stem cells. They are isolated from adult organisms and have nothing to do with cells isolated from embryos" - said Prof. Ratajczak.

As he noted at the press conference, the length of a person\'s life depends on many factors, both genetic and environmental, which include calorie restrictive diet and physical activity. "There is also increasing evidence that our life expectancy depends on the amount and condition of stem cells" - explained the researcher.

Research carried out earlier by the team of Prof. Ratajczak on laboratory animals showed that those with more VSELs in various organs could live up to 30 percent longer than their peers.

"These cells are so important because, as we constantly renew, our stem cells are working around the clock. For example, the intestinal epithelium is renewed every 4 days, and the skin every 2 weeks" - Prof. Ratajczak told PAP. VSEL count, however, decreases with age.

Recent experiments were performed on mice that ran daily a distance of approximately 1 km in a rotating wheel. First group of animals performed this strenuous exercise for only one day, the second every day for two weeks, and the third for six months.

Analysis carried out after killing the rodents showed that those who performed strenuous exercise for the longest period had more muscle and less fat than mice exercising less.

It also turned out that the animals exposed to the exercise for 6 months, the proliferation of VSELs in the bone marrow occurred, and the amount of VSELs in the peripheral blood increased. The researchers also confirmed on the basis of the study of gene activity that through strenuous exercise VSELs retained their comprehensive development possibilities (called pluripotency) longer.

"We believe that our observations of mice can be translated to humans, who have the same population of VSELs" - said Prof. Ratajczak. He noted also that it is very difficult to carry out similar studies on humans.

"We would have to have volunteers of all ages, but no one is willing to give bone marrow for testing. One could draw bone marrow during diagnostic procedures, but then we are usually dealing with sick people. However, we are trying to solve this problem" - he explained in an interview with PAP.

Prof. Ratajczak’s team also tests whether it is possible to affect the amount and quality of VSELs by reducing calories is a diet and through pharmacological intervention. "We have identified genes whose function we want to modify with drug therapy, to improve the performance of VSELs" - he said.

The research of Prof. Ratajczak’s team was funded by the EU\'s Operational Programme Innovative Economy (OP IE).

PAP - Science and Scholarship in Poland, from Atlanta Joanna Morga

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