What are Clara Cells?

The cells that are located in the distal airway are clara cells, which have a hemispherical shape with microscopic hair-like strands called microvilli. A primary task performed by clara cells is to guard the bronchial tissue against damage often caused by pollutants. The cells secrete a secretory protein and promote detoxification of the lungs. Significant damage to the clara cells can assist physicians in determining respiratory malfunction. One of the most common detections is damage caused by ozone, which may result in airway resistance, inflammatory reaction, and a decrease in lung function.

Distal airways are lined with cuboidal tissue and clara cells. Type I and Type II cells are also located in this area of the respiratory system. Clara cells act as a defense apparatus and assist in decreasing mucus that is created by various airways. Microvilli connected to the cells work to absorb and breakdown toxins that are inhaled, but injury to these cells can affect the defensive process.

Clara cells can expose signs of early damage to the lungs and airways, which specialists determine primarily by measuring the concentration of secretions. An increased exposure to toxins, such as ozone, will increase the amount of protein secreted because this defense mechanism begins to work overtime. This may be due to intravascular protein leakage into the bloodstream, which is measured to assess the risk of various pollutants on the respiratory system.

Functionality of clara cells does not fully develop until several weeks after birth. These cells are found predominantly in mammals and a few other species, including mice who are often used in cell research studies. The increased number of these cells and the amount of secretion is the key data in studies used to determine respiratory health. Aside from ozone, current research focuses on cigarette smoke, carbon monoxide, and large or small particles of dust created by various vehicles and machinery. Most of these pollutants directly affect the performance of these cells.

This cell was identified and described by Max Clara, an anatomist from Austria, in 1937. Clara was an active member of the Nazi party and performed research on executed prisoners from a concentration camp in Dresden, Germany. His Leipzig research team performed numerous experiments on cadavers received from local camps, which produced over 15 scientific papers pertaining to anatomy. Leipzig University appointed Clara as the chairman of the anatomy department prior to his discovery, which gave him full reign of laboratory facilities and resources.