Endocannabinoids as potential biomarkers: It's all about pre-analytics

Area of Science:

• Lipidomics
• Neuroscience
• Biomarker Discovery

Background:

• Arachidonoyl ethanolamide (AEA) and 2-arachidonoyl glycerol (2-AG) are key endocannabinoids involved in various diseases.
• Their utility as blood biomarkers is limited by pre-analytical variability and physiological factors.
• Accurate measurement is challenging due to low concentrations (ng/mL) and sample instability.

Purpose of the Study:

• Identify critical pre-analytical parameters for endocannabinoid (EC) determination in blood.
• Propose minimum requirements for reliable EC analysis.
• Reduce variability in EC measurements for clinical research.

Main Methods:

• Review of physiological processes affecting EC concentrations.
• Analysis of published pre-analytical research.
• Evaluation of stability data from bioanalytical method validation.

Main Results:

• Inter-individual factors (sex, metabolism, diurnal changes) influence EC levels.
• Enzymatic activity in fresh blood significantly alters AEA and 2-AG concentrations.
• Non-enzymatic isomerization also affects 2-AG levels.

Conclusions:

• Immediate processing of blood samples at low temperatures (<0°C) is essential for EC stability.
• Standardizing blood collection tubes, anticoagulants, sampling times, and processing duration reduces variability.
• Thorough participant characterization is needed to mitigate confounding co-variables in clinical data.