open lung stem cells a way to treat respiratory diseases. The research may help us understand how causes lung cancer. The Harvard team hopes to treat emphysema and pulmonary hypertension. The treatment is not yet ready for testing in people
Researchers at Harvard Medical School (USA) have discovered a cell type previously unknown in the human body. This is stem cells of the lungs, as has been demonstrated in a series of experiments, have the ability to regenerate damaged lungs. From these stem cells can form not only different types of cells that make up a lung, but also the blood vessels supplying the respiratory system.
Research is a step ahead of understanding how lung diseases originate. Of these, lung cancer is the leading candidate to be related to alterations of stem cells.
On the other hand, the research paves the way for developing new treatments for respiratory diseases utilizing the capacity that have shown stem cells to regenerate lung tissue.
"We believe that these cells have the potential used against a wide range of lung diseases including emphysema (which causes severe respiratory failure) and pulmonary hypertension, "said Joseph Loscalzo, co-author, by email. The treatment would remove a sample of lung tissue from patients, isolating the stem cells multiply in the laboratory and re-entered in the lungs to regenerate damaged. Because these cells would have been obtained from patient's own tissue, not cause immune rejection.
A potential test of lung stem cells is that the findings were presented today The New England Journal of Medicine, a journal specializing in publishing research that change the way medicine is practiced. For now, however, these cells have regenerated only in mice lungs, so they are not ready for use in humans.
Harvard researchers to identify the lung stem cells has been like finding the needle in the haystack. Since lung tissue that had been donated for transplantation and were not used, and lungs of fetuses that had died, the researchers looked for cells that have a protein called c-kit. They focused on this protein because, in the heart, to identify cardiac stem cells.
In the lungs, they found, only one in 6,000 cells of the bronchioles, and one of every 30,000 of the alveoli, are the protein c-kit (see chart). These few cells isolated and cultured in the laboratory. Noted that had the ability to divide as do stem cells, producing one hand a new stem cell and, secondly, a differentiated cell lung characteristic.
After producing hundreds of thousands of these cells, inoculated mice with lung injuries. Each mouse received about 20,000 cells human. After two days, 25% of these cells had been implanted in the lungs of mice and were dividing. After two weeks, the cells had restored bronchioles, alveoli and blood vessels. An analysis confirmed that the regenerated tissue was composed of human cells, which were integrated with the normal tissue of mice.
Previous studies have identified progenitor cells can give rise to more specialized cells in different regions of the lungs. But this is the first identified a stem cell can form any cell type lung.
"It's a spectacular research," said Thomas Graf, ICREA researcher who heads the group of stem cell research at the Centre for Genomic Regulation (CRG). "If these results are replicated in other laboratories, opening the way to propose autologous (own cell) for patients with respiratory diseases."
Ángel Raya, ICREA researcher and stem cell specialist at the Institute of Bioengineering of Catalonia (IBEC), agrees that "the first thing to do is reproduce the data in other laboratories" so that these stem cells can be used medical purposes.
Harvard team plans to repeat the research in animals other than mice tested in people before a treatment based on stem cells in the lungs. "We'll try it in a large animal model in the near future. Is a necessary step before considering a clinical trial in people, "said Piero Anversa, director of research, e-mail.
Another issue that should be studied, Anversa says, is what is the best way to get stem cells from patients and re-administered after they have been multiplied in the laboratory. Direct injection cells in the lungs that has been used in research on mice could be impractical in humans. As alternatives, the Harvard team contemplates the possibility of administering the cells by a bronchoscopy, which allows access to a thin tube into the lungs, or by inhalation with a nasal spray.
The different types of stem cells
ADULT
have ability to form specific cells or tissues such as lung stem cells identified now. Its medical use dates back to 1959, when it became the first transplant bone marrow. The advances of the last decade have renewed interest in them.
EMBRYONIC
have the capacity to become any cell in the body. U.S. scientists discovered in 1998 how to grow embryonic stem cells in the laboratory, which stimulated this research area and provoked fierce ethical debate.
IPS
iPS cells are derived from adult cells but behave like embryonic stem cells by genetic reprogramming technique introduced in 2006 by researcher Japan's Shinya Yamanaka. This technique avoids the ethical debate of embryonic stem cells.
Source: lavanguardia.com
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