2022 Annual Meeting and Alumni Reunion
Category : Clinical Research Candidate : Kristen Pitts Poster #: C12
APOE and Galectin-3 , Markers of Activated Microglia , are Elevated in the Aqueous Humor of Glaucoma Patients
Kristen Pitts , Cameron Neeson , Nathan Hall , Henisk Falah , Milica Margeta , David Solá-Del Valle
Purpose : Microglial activation has emerged as a critical event contributing to retinal ganglion cell loss in glaucoma . Apolipoprotein E ( APOE ), the major apolipoprotein in the brain , and Galectin-3 ( Gal-3 ), a secreted carbohydrate-binding lectin , have been identified as molecules critical for microglial cytotoxicity in mouse models of glaucoma . In this study , we aim to examine the role of APOE and Gal-3 in human disease by analyzing their concentrations in aqueous humor ( AH ) collected from glaucoma patients and healthy controls .
Methods : AH was collected from 71 patients at the start of surgery , including 57 glaucoma patients undergoing various ophthalmic procedures and 14 control patients undergoing routine cataract surgery . APOE and Gal-3 levels were quantified by enzyme-linked immunosorbent assay and total protein concentration by bicinchoninic acid ( BCA ) assay . Patients ’ medical records were carefully reviewed to collect relevant preoperative data . Descriptive statistics , Pearson ’ s correlation coefficient , and multivariate linear regression analyses were conducted to characterize associations between clinical and demographic variables and APOE and Gal-3 levels .
Results : APOE and Gal-3 levels were significantly elevated in the AH of glaucoma patients ( 1.64 +/ - 1.45 μg / mL and 2.33 +/ - 2.09 ng / mL , respectively ) compared to controls ( 0.40 +/ - 0.19 μg / mL , 0.92 +/ - 0.81 ng / mL ) [ p < 0.001 ; p = 0.004 ]. APOE and Gal-3 levels were moderately positively correlated across the entire cohort ( r = 0.65 , p < 0.001 ). No association was observed between APOE and total protein or Gal-3 and total protein , indicating that APOE and Gal-3 levels were not increased in glaucomatous AH due to nonspecific protein accumulation ( p > 0.3 ). Multivariate linear regression analyses revealed significant associations between Gal-3 and maximum recorded intraocular pressure measurement ( p = 0.009 ), and between APOE and number of past ophthalmic surgeries ( p = 0.031 ).
Conclusions : Our findings demonstrate that APOE and Gal-3 are increased in the AH of glaucoma patients and significantly correlate with clinical measures of glaucoma severity . Thus , these molecules could serve as biomarkers to identify patients who may benefit from microglia-based neuroprotective glaucoma therapies .