Blocking Calcium-Sensing Receptors Could Treat Asthma

For about 10 to 15% of patients with asthma, inhaled corticosteroids, which are standard asthma medications, don’t have much effect in decreasing symptoms such as wheezing and shortness of breath. Now, researchers report that calcium-sensing receptors (CaSRs) could be novel targets for asthma drugs. The receptors are found in many tissue types and bind positively charged ions and biomolecules. Daniela Riccardi of Cardiff University, in Wales, and her colleagues decided to look at CaSR because levels of positively charged proteins, such as eosinophil cationic protein, are elevated in the lung mucus and blood of asthmatic patients. The team found higher expression levels of CaSRs in airway smooth muscle tissue samples from asthmatic patients compared with levels in healthy people. In two types of mice with asthmalike symptoms, inhaled CaSRs antagonists (one shown) reduced airway constriction and hyperactivity, and also decreased the number of immune cells in lung fluid, a sign of inflammation (Sci. Transl. Med. 2015, DOI: 10.1126/scitranslmed.aaa0282). Although the results are promising, data from mouse models of asthma are not always great predictors of success in patients, says Elliot Israel, who studies asthma at Brigham & Women’s Hospital, in Boston.