December 1, 2011
Cystic Fibrosis and the Prospect for Gene Therapy
Every single second, someone somewhere in the world dies. Diseases, viruses, and bacteria are taking over our universe. The only question left to ask now is, what can we do about this? Where would the world be if doctors could insert a functional gene into an individual’s cell and their defective DNA no longer exists? “The road to successful human gene therapy has been long, hard, and scattered with false hopes and unexpected and accidental consequences”. Cystic Fibrosis is a fatal disease caused by genetic defects in a transport protein in the plasma membrane. The parts of the body that are most noticeably affected are the lungs, pancreas, and sweat glands. Scientists studying and researching gene therapy are now “trying to develop new treatments or perhaps even a cure for the disease” (Becker, Wayne M.: The World of the Cell). One such approach is gene therapy in which a “normal copy of a gene is introduced into affected cells of the body” (Becker, Wayne M.: The World of the Cell). With the modernization of Gene therapy, scientists can insert genes into an individual’s cell and biological tissues to treat disease such as cystic Fibrosis where harmful mutant alleles are replaced with functional ones. Scientific advancements could lead to gene therapy in exchange for modern medicine. First, I will discuss the background on cystic fibrosis, as well as the background on a gene and how gene therapy can be achieved to treat diseases such as Cystic Fibrosis.
The transport proteins that are in the plasma membrane play an important role in speeding up and controlling the movement of molecules and ions in and out of the cell. For humans to remain healthy, our bodies are reliant on the proper functioning of such membrane proteins. If any of these proteins are defective, the movement of a particular ion or molecule across the cell membrane is likely to be weakened, and a disease may result such as Cystic Fibrosis.
Since the lungs, pancreas, and sweat glands are the symptoms most noticeably affected, difficulties in the lungs are the most severe medical problem because they are the most difficult to treat which can become life-threatening. The airways of a Cystic Fibrosis patient are often clogged with abnormally thick mucus and are more vulnerable to “chronic bacterial infections, especially Pseudomonas aeruginosa” (Becker, Wayne M.: The World of the Cell).
During the 1980’s, cells from Cystic Fibrosis patients were shown to be defective in the discharge of chloride ions. “The cells that line unaffected lungs secrete chloride ions in response to a substance called cyclic AMP, whereas cells from Cystic Fibrosis patients do not” (Becker, Wayne M.: The World of the Cell). To understand this more, cyclic AMP is a form of AMP that is involved in a variety of controlling roles in cells for its structure. Experiments were done with the tissue from Cystic Fibrosis patients and researchers suggested that this difference might be due to a defect in the movement of chloride ions across the membrane. Many of the symptoms Cystic Fibrosis patients experience can be explained by faulty discharge. Cystic Fibrosis is caused by a “defect in the secretion of chloride ions in cells lining the lungs, leading to insufficient hydration and the promotion of bacterial growth” (Becker, Wayne M.: The World of the Cell). When comparing to a healthy unaffected person, chloride ions in their lungs are discharged from the cells lining the airways and enter the lumen of the passage normally. The movement of Chloride Ions out of the cell and into the lumen provides the driving force for the concurrent movement of sodium ions into the lumen. “Osmotic pressure causes water to follow the sodium and chloride ions, resulting in the secretion of a dilute salt solution. The water that moves into the lumen in this way provides vital hydration to the mucus lining of the air