Plasmalogens Are Emerging Biomarkers and Therapeutic Targets Across Multiple Diseases

Plasmalogens are structurally unique phospholipids distinguished by a vinyl-ether bond at the Sn-1 position rather than the ester bond found in conventional phosphatidylcholine or phosphatidylethanolamine. Comprising 5–20% of mammalian cell membrane phospholipids, they are concentrated in lipid rafts, myelin sheaths, platelets, and erythrocytes. Their reduction in circulation or cell membranes is now recognized as a consistent signal of disease progression across many organ systems.

The clinical biomarker evidence presented is broad and striking. In cardiovascular disease, HDL-associated and plasma plasmalogen levels (particularly PC plasmalogens) are significantly lower in coronary artery disease and acute myocardial infarction patients versus healthy controls, correlating with impaired endothelial cell survival. In kidney disease, plasmalogen depletion worsens with disease stage and predicts cardiovascular mortality in end-stage renal disease patients. Liver disease — including NAFLD and NASH — shows declining plasmalogen dimethyl acetals alongside rising lipoxygenase eicosanoid metabolites. In neurological disease, plasma PE plasmalogens decline in Alzheimer's and Parkinson's patients, and higher PE36:4 plasmalogen levels are associated with a significantly reduced risk of MCI-to-AD progression. Notably, oral supplementation with scallop-derived ether phospholipids for 24 weeks restored Parkinson's patient plasmalogen levels to near-healthy values and improved clinical symptoms.

In systemic inflammatory and infectious diseases, COVID-19 severity inversely correlates with plasmalogen levels in serum and platelets. SLE patients show depleted PE plasmalogens in both PBMCs and serum, accompanied by elevated lipid peroxidation products. Across multiple cancers — breast, ovarian, pancreatic, and hepatocellular carcinoma — plasma PE or PC plasmalogens are consistently lower in patients, and in ovarian cancer, the ceramide-to-plasmalogen ratio outperforms CA-125 as a prognostic indicator.

The mechanistic picture is equally rich. Plasmalogen synthesis is initiated in peroxisomes (via GNPAT, AGPS, and FAR1 enzymes) and completed in the endoplasmic reticulum. Their catabolism intersects with platelet-activating factor (PAF) production, a potent inflammatory mediator. Enzymes involved in plasmalogen metabolism — including iPLA2 — also regulate ferroptosis, autophagy (via ULK1), mitochondrial respiratory homeostasis, toll-like receptor signaling, and cholesterol efflux via liver X receptors. Rare peroxisomal disorders like rhizomelic chondrodysplasia punctata (RCDP) illustrate the catastrophic consequences of complete plasmalogen synthesis failure.

Dietary supplementation with plasmalogens or biosynthetic precursors is being evaluated in small human trials for sleep disorders, cognitive decline, Parkinson's disease, and other conditions. Key caveats include heterogeneous mass spectrometry protocols across studies, mass overlaps between lipid species, lack of commercially available standards for all plasmalogen classes, and the predominantly small-scale nature of human clinical studies. Nonetheless, plasmalogens represent a compelling convergence point between aging-relevant biology — oxidative stress, membrane integrity, neurological function, and inflammation — and measurable, potentially modifiable biomarkers.