Ethylated Phosphorylcholine as a New Marker for Alcohol Consumption: A Proof of Concept

Alcohol consumption is widespread worldwide and a leading cause of injuries, morbidity, and mortality. Accurately detecting alcohol use with reliable biomarkers is crucial in clinical and forensic settings. Direct alcohol biomarkers, i.e., ethanol (EtOH), ethyl glucuronide (EtG), ethyl sulphate (EtS), phosphatidylethanol 16:0/18:1 (PEth) reflect short- and long-term consumption. Nevertheless, complementary biomarkers with improved specificity and sensitivity are needed to better assess alcohol use, including generating a detailed timeline of consumption. In vitro exposure of HepaRG liver cells to EtOH resulted in the generation of ethylated phosphorylcholine (EtOChoP). This is the first study to investigate the in vivo presence of EtOChoP and its occurrence in medico-legal samples. Proof-of-concept and observational studies assessed EtOChoP, PEth, EtG, EtS, and EtOH in whole blood, and, when available, other matrices were analyzed for EtG, EtS (plasma, serum, urine, hair), EtOH (urine), and EtOChoP (plasma, serum). A single alcohol exposure event (0.5 g/kg EtOH, with blood EtOH concentration peaking at 0.76 g/L at 100 min) led to EtOChoP presence, and, similar to short-term biomarkers (e.g., EtOH, EtG, and EtS in whole blood), EtOChoP was not detected in the following day(s). However, in the observational study, EtOChoP remained detectable even when short-term biomarkers were absent, resembling long-term biomarkers (PEth and hair EtG). Notably, 14% of samples were positive only for EtOChoP, highlighting the need for additional biomarkers. These findings identify EtOChoP as a promising alcohol (ab)use biomarker formed after EtOH consumption and possibly accumulating during chronic drinking. EtOChoP could potentially differentiate between recent drinking and chronic problematic drinking in individuals with high PEth levels.