Cystic Fibrosis Therapies

Although no definite cure has been discovered for cystic fibrosis as of yet, many treatments have been developed to improve the quality of life for those who suffer from this disorder. Since CF causes a build-up of mucus in the lung tissue, the respiratory diseases which result are often the actual cause of death, not CF itself.

Thus many with cystic fibrosis take an assortment of antibiotics daily to combat these infections. Perhaps most well known to CF is the chest beating of the patient. This allows the mucus to be loosened and expectorated to reduce further infection. Since a great deal of the mucus has been identified as the DNA from collected dead white blood cells, drugs such as Pulmozyme (dornase alfa) have been developed as enzymes which thins the mucus lining the lung tissue. In extreme cases, lung transplants have been performed when the lungs can no longer function properly despite the use of the aforementioned treatments. The digestive system is also affected in those with CF as certain pancreatic enzymes needed for digestion are not able to reach the small intestine. This prevents the ability of the body to process and obtain energy from ingested food.

However, medications such as Mucomyst have been developed in order to replace missing enzymes in the patient's digestive system. Thus, proper nutrition and aerobic exercise, such as running and swimming, contribute greatly in physical endurance as the patient increases the amount of deficient nutrients in addition to increasing lung capacity. While searching for treatments for the symptoms of cystic fibrosis, the pain reliever Ibuprofen has been used extensively in treating children between the ages of five and thirteen. Ibuprofen has been shown to be useful in reducing feelings of discomfort, yet the medication does not appear to have any significant effects in adults and several negative side-affects have been noted as a consequence of its usage. Although they have been suggested, sodium channel blockers to the epithelial tissue have shown conflicting results in terms of its usage as a possible treatment. Another possibility lies in the upregulation of the chloride channels in those with CF. Using ATP or UTP as possible mediums in this treatment, the chloride ions have the potential for avoiding malfunctioning channels. This treatment would also allow greater passage of ions through other channels present in airway epithelial tissue. Perhaps one of the most promising developments is the FDA's consideration of the drug "CPX" as an "orphan drug" to be tested for potential treatment of CF. The manufactures, SciClone Pharmaceuticals, Inc. through in vitro studies have shown that CPX is able to bind to the CFTR protein. This would permit it to function normally, allowing the chloride ions to be moved across its designated channel in cells. Although many possibilities in pharmaceutical treatment have been proposed, the longer average life span of those suffering from CF has resulted from a strict regimen of diet, antibiotics, and aerobic exercise. Instead of CF patients living only to their teenage years at most, many have endured to the age of thirty which provides hope in the advent of improved medications and treatments.

Gene Therapy for Cystic Fibrosis

There have been several strategies for attacking cystic fibrosis, but the most prevalent study deals with gene therapy which distributes a normal copy of the CFTR gene to the cells that require it (this guides the synthesis of normal CFTR protein). This method promotes the ability of viruses to enter cells. Adenoviruses, which behave as gene carriers, have become an area of close study since they are able to infect human airways and result in only non-deadly sickness such as the common cold. However, the results of the different findings mark that adenoviral vectors need to be improved greatly before they can serve as gene-delivery agents in therapy. The goals of gene therapy are to design an efficient method of introducing the cloned gene into the cells and to learn more about how that gene must function inside the somatic cell. It must be determined if the gene must be expressed in the affected tissue or if the release of the product protein at another site is just as effective. To optimize the function of the gene, the appropriate regulatory elements of the gene must be determined, such as directing transcription at proper levels in the appropriate cells. Even though the development of gene therapy is ongoing, problems have already arisen. The number of cells that must be correct for clinical benefit is unknown and the treatment may lead to over expression which could cause toxicity. The immune system may reject the vector (the cloned gene’s host). Gene therapy is also surrounded by a plethora of ethical concerns. The questions of when to treat a patient, who to treat, authorization of a minor’s treatment, and cost effectiveness of the procedure all have a bearing on the future of gene therapy for cystic fibrosis.

Information compiled from the article "Gene therapy for Cystic Fibrosis: A Potential Cure" in the April 1996 issue of the Maryland Medical Journal, www.mayo.ivi.com, www.gourmetconnection.com, www.familyinternet.com, and www.pslgroup.com/dg/24ee6.htm