Researchers at Johns Hopkins may have recently outdone themselves. Based upon data from a recent study, they may have identified a way for people with COPD to regrow their alveoli, the tiny air sacs in the lungs that get destroyed after long-term exposure to tobacco smoke and other noxious stimuli.
The alveoli, located deep within the lung, play a starring role in the respiratory system as within their tiny walls, the process of gas exchange takes place. In the healthy lung, the exchange of oxygen and carbon dioxide is well-balanced; in COPD, it is not. The destruction of the alveoli commonly seen in emphysema impairs the process of gas exchange, often leading to hypoxemia and hypercapnia, two potentially dangerous complications of COPD. To date, there is no effective treatment that can repair damaged alveoli, once they've been destroyed.
During the experiment, scientists used hepatocyte growth factor (HGF), a protein that regulates cell growth and motility, to regrow alveoli and restore lung structure in mice that were genetically engineered to have a human-like form of emphysema. The study consisted of three groups of mice. Half of the mice received HGF, delivered by way of a special pump under their skin, while the other half received a placebo. In addition, a control group was formed, using mice with healthy lungs in which half received either HGF or a placebo.
Senior study author Enid Neptune, M.D., associate professor of pulmonary and critical care medicine at the Johns Hopkins University School of Medicine, reported the following findings:
"We found that the mice with emphysema, when given the HGF, developed a 17 percent improvement in the size of their air sacs compared to placebo-treated mice, consistent with improved lung structure and function. The HGF also was protective, preventing destruction of the alveoli by reducing the oxidative stress that contributes to lung injury. In essence, the HGF was able to block a major enemy of the functioning alveoli."
Additional findings were as follows:
- Control-group mice with healthy lungs that received HGF demonstrated no change in the size of their alveoli.
- Mice with emphysema that were treated with a placebo showed no improvement.
- As suspected, when scientists removed the HGF receptor from young mice with developing lungs, they found that their alveoli did not form correctly, that the blood vessels supplying the alveoli were fewer in number and that there was an increase in oxidative stress and inflammation.
According to Dr. Neptune, the study was "an important demonstration that a growth factor can be used as a drug for emphysema." It was pointed out however, that because HGF reduces cellular death and promotes proliferation of cellular growth, further research is necessary to find a way to hone-in on activating the protein's therapeutic benefit, instead of it's potential to cause malignancy and cancer.
Medicine, Johns Hopkins. "New Air Sacs Created In Mouse Model Of Emphysema Using Novel Growth Factor." Medical News Today. MediLexicon, Intl., 18 Feb. 2013. Web. 26 Feb. 2013.