Medical science has held that when lung tissue dies, it cannot be replaced. But now it just might be regenerated, according to recent stem cell research. This means hope for sufferers from emphysema, chronic bronchitis and chronic asthma, together known as chronic obstructive pulmonary disease (COPD). About 7.5 per cent of the world's people suffer some degree of COPD. It is the fourth leading cause of death worldwide. Thus, researchers around the world are involved in finding a cure. Some clinics abroad already offer experimental treatments.
Renewal and Repair of Lung Tissue
At the University of North Carolina School of Medicine, a medical research team concluded that somatic, or adult, stem cells can renew themselves abundantly. They can also repair specific cells. Difficulties arise in furthering this process because the body tends to conserve its stem cells, so it is a matter of finding a way to release more of these cells.
Difficulty Regenerating Lung Cells
Lung cells are among the most complex of the body's cells. Scientists believe that over 40 different types of cells make up lung tissue. Yet, they all derive from one type of cell---the precursor cell. Researchers hope that stem cell therapy will be able to multiply these precursor cells so that they, in turn, will differentiate into all the other lung tissue cells. If this research goal can be achieved, the lung sacs will self-renew to the point where they can again absorb oxygen.
Progress Toward the Goal
New areas of stem cell exploration seem limitless. But present discoveries are substantial. According to the article, "Stem Cell and Regenerative Medicine," published on the New Jersey Medical School website, researchers have already isolated cells that form vascular structures in lung tissue, necessary for delivering oxygen to the bronchia's outer tissue. They also may have pinpointed the source of lung cell progenitors---the "parent" cells. The article concludes: "The future of lung stem cell research is both exciting and promising, with only the human mind as the barrier to a plethora of possibilities."
Mice and Humans
In experiments, Japanese researchers at Tohoku University School of Medicine, Japan, hypothesised that bone marrow-derived cells (BMCs) may aid lung tissue to regenerate itself. Mice treated this way showed a significant increase in alveoli numbers and in reduction of emphysema symptoms. By using immunofluorescent staining, tests showed that the BMCs travelled to specific lung cells. This evidence led researchers to conclude that lung parenchyma (alveoli tissue) might be regenerated with stem cell therapy.
Therapy Now Available
In the United States, stem cell treatments are still quite limited and conducted on an experimental basis. Some countries that already have clinics offering this therapy are China, Argentina, Mexico, Germany and about a dozen others. The International Cellular Medicine Society keeps records of these.
- Virtual Medical Centre: Emphysema
- Respiratory Research: Stem Cells and Repair of Lung Injuries
- New Jersey Medical School, Graduate School of Biomedical Science: Stem Cell and Regenerative Medicine
- "FEBS Letters"; Bone Marrow-Derived Cells Contribute to Lung Regeneration; Ishizawa, et al.; 2004.
- International Cellular Medicine Society: Offshore Clinic Report