Various other drug-based treatments, including the use of mucolytics to break up thick, viscous sputum and the use of osmotic agents to keep airways moist, are well established in CF treatment protocols, but research continues in order to refine and improve on these approaches as well.
A novel therapeutic method being tried for CF is "the modulation of non-CFTR ion channels in epithelial cells." (Jones & Helm, 2009). The drug Lancovutide (Milil901, duramycin) "activates an alternative chloride channel in epithelial cells by elevating intracellular calcium levels, and thus, may potentially compensate for CFTR deficiency in the airway epithelium." (Jones & Helm, 2009). These agents have reached the clinical trial stage, and, if successful, will be able to offer a new category of treatment option for CF patients.
Gene therapies, which seek to correct "the underlying gene effect, either by agents that help to correct the dysfunctional CFTR . . . Or by gene transfer" (Jones & Helm, 2009), are particularly promising. The gene defect that causes CF was first identified in 1989, and since then researchers have explored treatments that would replace the patient's defective CFTR with "wild-type" CFTR (Jones & Helm, 2009).
For example Zhang, et al. have focused on the development of gene transfer strategies using epithelial cells. They used "an in vitro model of human CF ciliated surface airway epithelium…to test whether a human parainfluenza virus vector engineered to express CFTR could deliver sufficient CFTR…to restore mucus transport, thus correcting the CF phenotype." (Zhang, et al., 2008). The team was able to determine that normal mucus transport rates were restored after "CFTR delivery to 25% of surface epithelial cells." (Zhang, et al., 2008). Additional study will help develop this corrective gene transfer approach and determine how best to use the technique and how far it can go towards restoring normal mucus transport function in CF patients.
One factor contributing to the advancement of research to treat CF is the availability of stem cells for experimental use. Recently, two new human embryonic stem cells lines have been produced affected by CF. (Deleu et al., 2009) This new source of "feeder cells" offers researchers ease and availability of a medium for continued research studies in the laboratory prior...
Namely, "[t]hese new genetic cell lines represent an important in-vitro tool to study the physiological processes underlying this genetic disease, drug screening, and tissue engineering." (Deleu et al., 2009). Especially with a disease such as CF, where the patient population is made of up a majority of minor children, having stem cells as an option can help advance trials further than was possible in the past, without any of the ethical concerns involved with using children as live trial subjects, until various treatment approaches are well advanced in the study cycle.
In summary, various drug-based treatments have become standard for CF, and continue to contribute to improved care and health status for these patients, with improvements in administration method (e.g., dry inhalers) continuing to increase efficacy of known treatments. Meanwhile, the potential for significant leaps forward in treatment of the disease are presented by new gene therapies -- supported by the greater availability of stem cell-based research techniques. With this focus on CF from multiple fronts and using multiple modalities, we can hope that the advancements of the last 50 years, which extended the lifespan of CF patients into adulthood, can be repeated, offering CF patients of the future the opportunity to experience a full life span into old age.
References
Cystic Fibrosis Foundation (n.d.). Retrieved 15 April 2010 from the Cystic Fibrosis Foundation website, http://www.cff.org/
Deleu, S. et al., (2009). Human cystic fibrosis embryonic stem cell lines derived on placental mesenchyman stromal cells. Reproductive BioMedicine Online, 18(5), pp. 704-716.
Jones, A.M. & Helm, J.M. (2009). Emerging Treatments in Cystic Fibrosis. Drugs 69 (14), pp. 1903-1910.
Kids Health (n.d.). What is Cystic Fibrosis, Retrieved 15 April 2010 from the Kids Health website http://kidshealth.org/parent/medical/lungs/cf.html
Seattle Children's Hospital (n.d.). Advancing Cystic Fibrosis Care, Retrieved 15 April 2010 from the Seattle Children's Hospital website http://www.seattlechildrens.org/about/stories/forward-thinking/
Zhang, L. et al. CFTR Delivery to 25% of Surface Epithelial Cells Restores Normal Rates of Mucus Transport to Human Cystic Fibrosis Airway Epithelium. PloS Biology 7(7), pp. 1-15.
