Researchers identified 19 potential aqueous humor biomarkers that may indicate polypoidal choroidal vasculopathy (PCV), according to research published in Experimental Eye Research

Investigators collected and analyzed aqueous humor samples from patients with PCV (n=16, mean age 63.7±11.0 years, 8 men) and age- and sex-matched control individuals (n=28, mean age 64.6±9.8 years, 15 men) between April and September of 2021. They performed comprehensive eye exams including best-corrected visual acuity (BCVA), biomicroscopy, color fundus photography, spectral domain optical coherence tomography (SS-OCT), and fluorescein and indocyanine green angiography. The team noted no significant differences in age, gender, smoking status, alcohol consumption, fasting blood glucose, or serum levels of triacylglycerol (TG), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) between the 2 groups. 

Investigators identified 33 lipid classes and 639 lipid species. The mean total lipid concentrations of aqueous humor in patients with PCV and control participants were 185.34±53.11 μg/mL and 165.05±19.85 μg/mL, respectively (P =.075). They identified 50 lipids including 17 phosphatidylcholines (PCs), 10 triglycerides (TGs), 8 diglycerides (DGs), 3 phosphatidylinositols (PIs), 3 sphingomyelins (SMs), 2 ceramides (Cers), 2 lysophosphatidylglycerols (LPGs), 1 cholesterol ester (ChE), 1 phosphatidic acid (PA), 1 phosphatidylethanolamine (PE), 1 phosphatidylglycerol (PG), and 1 phosphatidylinositol-phosphate (PIP). Among the 50 lipids identified, the team considered 19 as potential biomarkers for PCV (area under the receiver operating characteristic curve (ROC) ≥0.85). 


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Researchers speculate that LPG may play a pivotal role in the pathogenesis of PCV due to LPG (13:0) and LPG (11:0) being the 2 most up-regulated species. Increased glycerophospholipid levels suggest that glycerophospholipid metabolism was the most significantly altered metabolic pathway in PCV.

“Lipids are abundant in most tissues and play a wide range of biological functions by regulating various signaling pathways,” according to the investigators. “Under highly matched systemic and ocular conditions, we found abnormal lipids expression in aqueous humor of PCV patients, suggesting those lipids might participate in the local inflammation or pro-angiogenesis in PCV eyes.”

Study limitations include a small sample size, single center design, and failure to validate results with a standardized quantitative method. 

Reference

Liu B, Cong C, Li Z, et al. Analysis of the aqueous humor lipid profile in patients with polypoidal choroidal vasculopathy. Exp Eye Res. Published online June 23, 2022. doi:10.1016/j.exer.2022.109160