Detection of chlorinated DNA and RNA nucleosides by HPLC coupled to tandem mass spectrometry as potential biomarkers of inflammation

Upon inflammation, activated neutrophils secrete myeloperoxidase, an enzyme able to generate hypochlorous acid (HOCl) from hydrogen peroxide and chloride ions. An analytical method, involving HPLC coupled to electrospray tandem mass spectrometry, has been set-up to detect low levels of HOCl-induced nucleic acids lesions, including both ribo and 2'-deoxyribonucleoside derivatives of 8-chloroguanine, 8-chloroadenine and 5-chlorocytosine. Validation of the developed method was achieved using isolated cells treated with HOCl. The method was found to be sensitive enough to allow the measurement of background levels of 5-chloro-2'-deoxycytidine in the DNA of human white blood cells isolated from 7 mL of blood.