Examining Phosphatidylethanol (PEth) Formation Rates Within and Between Subjects in Ex Vivo Whole Blood

Area of Science:

• Biochemistry
• Pharmacology
• Clinical Chemistry

Background:

• Interpretation of phosphatidylethanol (PEth) levels is challenging due to significant inter-individual variability in concentrations following ethanol exposure.
• Previous studies suggest differing PEth formation rates contribute to this variability, but lack within-subject assessments.

Purpose of the Study:

• To assess the variability of PEth formation rates in ex vivo whole blood across various ethanol concentrations.
• To investigate within-subject consistency of PEth formation rates over a one-month period.
• To examine the relationship between phosphatidylcholine concentration and PEth formation rate.

Main Methods:

• Whole blood samples from 10 participants were incubated with ethanol (0-236.7 mg/dL) at 37°C.
• PEth 16:0/18:1 concentrations were measured hourly for 5 hours using HPLC-MS/MS.
• PEth formation rates were calculated via linear regression; experiments were repeated one month later.

Main Results:

• PEth formation rate increased with ethanol concentration, showing inter-individual variability but intra-individual consistency.
• Four individuals exhibited differing PEth formation rates at the same ethanol concentration across two collection timepoints.
• No correlation was found between phosphatidylcholine concentration and PEth formation rate within participants.

Conclusions:

• PEth formation rate exhibits both inter-individual and intra-individual variability.
• PEth concentrations are more reliable for monitoring an individual's ethanol consumption trends over time rather than for between-individual comparisons.