Rejuvenate old cells to embryonic age
The possibility of using embryonic stem cells (ESCs) to repair damaged organs and tissues has long been exciting the minds of researchers. However, the transition from theory to practice turned out to be very difficult, partly due to the emergence of ethical and moral issues related to the need to destroy human embryos.
The method of returning adult cells to an undifferentiated state, discovered in 2007, gave rise to a new wave of research devoted to the development of approaches to the creation of new muscle, cardiac and even nerve cells from the patient's own biological material.
However, the results of a large number of experiments have shown that the techniques commonly used to create these so–called induced pluripotent stem cells (iPSCs) are less effective or do not work at all when trying to return the cells of elderly people to the "embryonic" state - and it is the elderly who most need new methods of regenerative medicine.
The barrier to the rejuvenation of the cells of the elderly has become the so–called physiological aging of cells - a natural process that triggers cell death when certain intracellular processes are disrupted.
French researchers from the University of Montpellier, working under the leadership of Jean-Marc Lemaitre, decided to modify the standard set of factors used to create induced pluripotent stem cells by adding two additional ingredients to it: NANOG and LIN28 transcription factors.
Experiments with cells of people aged 74 to 101 years have demonstrated the effectiveness of the new approach. Its use provided a "reset" of several critical markers of cellular aging, including telomere length.
Telomeres are small end sections of chromosomes whose length shortens with each cell division. When the telomere length reaches a critically small value, the cell dies. However, telomere length can be at least partially restored with the help of the enzyme telomerase, the level of activity of which is one of the key parameters that determine the lifespan of both cells and the organism as a whole.
According to the researchers, the new complex of factors also leads in reprogrammed cells such parameters as gene expression profiles, levels of oxidative stress and metabolism of the energy centers of the mitochondrial cell to indicators characteristic of stem cells.
Reprogramming your own cells looks like an optimal strategy for developing cell therapy methods for elderly people. However, experts note that the theoretical results obtained are still very far from their implementation into clinical practice. Moreover, the results of recent experiments on mice indicate that the use of induced pluripotent stem cells may be associated with a number of unforeseen problems, such as rejection by the immune system, observed even in cases when cells are isolated from the recipient's body.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Medical Xpress: 'Rejuvenated' stem cells coaxed from centenarian.
03.11.2011