Beyond lipid homochirality: Analytical strategies and biological implications

Nucleotides, carbohydrates, amino acids, and lipids have long been considered homochiral within mammalian systems. However, an increasing number of studies have reported a variety of chiral metabolites across various living organisms, some biologically active and others identified as potential disease biomarkers. Enantiomers of the same compound may have distinct biological activities, chemical reactivities, and metabolism, highlighting the increasing attention to molecular chirality in biomedical research. Like peptides, amino acids, and organic acids, lipids also possess chirality and are essential components of biological membranes, influencing both structure and functionality. Studies using simple model systems, like liposomes and vesicles, challenge the assumption that only homochiral membranes are stable, demonstrating comparable stability in racemic heterochiral membranes. Nevertheless, chirality within eukaryotic cells remains largely overlooked, resulting in limited understanding of its impact on lipid membrane organization, lipid-lipid and lipid-protein interactions, and the overall lipid metabolism. This gap primarily reflects the lack of robust experimental methods for chiral lipidomics profiling. This review provides a comprehensive overview of analytical techniques used for the separation and analysis of chiral lipids in complex biological samples, emphasizing advances in chromatographic and mass spectrometric techniques, and their application in disease biomarker discovery. We also discuss the structural and functional impact of chirality on phospholipid membranes and highlight future directions in chiral lipidomics research.