In the 19th century, a tuberculosis outbreak killed every one in seven people worldwide. Scientists believed it to be a genetic disease that mainly children developed making it known as “the robber of youth”. It wasn’t until the year 1882 that Robert Koch’s discovery of tubercule bacillus revealed that tuberculosis was not a genetic disease but highly contagious. Although there was some hesitation in the medical community at first, Koch’s findings helped the U.S. launch massive public health campaigns to educate the public on tuberculosis prevention and treatment. Later in 1904, “William Osler and William Welch, together with Edward Livingston Trudeau, founded the forerunner of the American Thoracic Society, the National Association for the Study and Prevention of Tuberculosis”. This sparked the beginning of pulmonary research – the conduction of clinically-oriented research into diseases and disorders affecting the lungs and respiratory tract (including molecular and cell-based investigations). With pulmonary research being around for more than 10o years, one would believe discovering something new at this point in history would be a long shot. But, recently researchers at the Perelman School of Medicine at the University of Pennsylvania found RASCs.
RASCs, also known as respiratory airway secretory cells, “line tiny airway branches, deep in the lungs, near the alveoli structures where oxygen is exchanged for carbon dioxide.” Scientists found that RASCs have stem-cell-like properties that allow them to regenerate other cells that are essential for normal functioning alveoli. They also discovered that smoking and the common smoking-related ailment called chronic obstructive pulmonary disease can disrupt the regenerative functions of RASCs. COPD is a chronic inflammatory lung disease that causes obstructed airflow from the lungs. Emphysema and chronic bronchitis are the two most common conditions that contribute to COPD (both bronchitis and emphysema affect the alveoli, the air sacks of the lungs). The study’s first author Maria Basil, states “COPD is a devastating and common disease, yet we really don’t understand the cellular biology of why or how some patients develop it. Identifying new cell types, in particular new progenitor cells, that are injured in COPD could really accelerate the development of new treatments,”. COPD causes around 3 million deaths worldwide and current treatments can only slow the disease down rather than stop or reverse it. Mice being the common test subjects in lab procedures lack key features of the human lungs, which leads scientists to use healthy human donors to discover RASCs. Since RASCs are secretory cells it means that they produce proteins needed for the fluid lining of the airway. An organelle that we know produces secretory proteins is the ribosome. Ribosomes are tiny organelles that contain RNA and specific proteins within the cytoplasm. Ribosomes are directly involved in the manufacture of proteins by using RNA and amino acids. The discovery of RASCs will not only help advance future COPD treatments but can also lead to discover ways to treat other lung dieases.