Abstract
Cocaine-related deaths present significant diagnostic challenges due to the nonspecific nature of cardiac histopathology and the limited reliability of postmortem toxicology, often affected by redistribution phenomena. This study investigated the postmortem heart expression and distribution of an anti-cocaine monoclonal antibody, aiming to evaluate immunohistochemistry (IHC) as a potential complementary tool for diagnosing cocaine-related fatalities. Fifteen cases of acute cocaine-related death, with toxicological data exclusively positive for cocaine, were examined and compared to ten cases negative for drug abuse. Cardiac samples from the lateral left ventricular wall and interventricular septum underwent IHC using an experimentally optimized protocol. All cocaine-related cases demonstrated clear and widespread immunopositivity, with varying staining intensities across a semi-quantitative scale. Immunostaining localized consistently to nuclear and myofibrillar compartments and showed no association with postmortem interval (mean PMI 72.33 h; range 30–144). Control samples exhibited no staining. Positive immunostaining also highlighted cardiomyocyte alterations related to cocaine toxicity, particularly hypercontracted fibers with myofibrillar rhexis and contraction band necrosis. While these findings align with the established cocaine-induced myocardial injury, the intense nuclear staining observed may further reflect oxidative DNA damage associated with cocaine exposure. This study provides novel evidence supporting the applicability of anti-cocaine IHC in postmortem investigations. The technique may serve as a valuable adjunct in detecting cocaine distribution within cardiac tissue, particularly when toxicological data are inconclusive or unavailable.