Oxidized low-density lipoprotein, lipid and calcium aggregates reveal oxidative stress and inflammation in the conjunctiva of glaucoma patients.

Abstract

Conjunctival specimens from primary open-angle glaucoma (POAG), exfoliation glaucoma (ExG) patients and controls were histologically analysed for oxidized low-density lipoprotein (ox-LDL), lipid and calcium aggregates. Our goal was to use them as biomarkers of oxidative stress and inflammation and to evaluate their correlation with glaucoma and impact on surgical outcome. Conjunctival samples were obtained from POAG (n=14) and ExG (n=17) patients and from control subjects (n=11) operated for macular hole, retinal detachment or strabismus. Immunohistochemistry was performed using the antibody against ox-LDL. Lipids and calcium were analysed by histochemical stainings with Nile red and Alizarin red S, respectively. Immunoreaction for ox-LDL was significantly increased in POAG (p= 0.049) and the number of lipid aggregates was significantly higher in ExG (p=0.009) when compared to control. When POAG and ExG patients were grouped according to the outcome of deep sclerectomy (DS) surgery, the number of lipid (p<0.001) and calcium aggregates (p=0.014) were significantly higher in the conjunctival stroma of patients whose surgery failed within a three-year follow-up period. The lipid-mediated alterations suggested the presence of oxidative stress and inflammation in the conjunctiva of glaucoma patients. The present data further support the role of oxidative stress and inflammation in the wound healing process leading to excessive scarring and failure in DS surgery.