Positive Association between Aqueous Humor Hydroxylinoleate Levels and Intraocular Pressure

Comparison of Schlemm's Canal Morphology Parameters Between Propensity Score-Matched Primary Open-Angle Glaucoma and Exfoliation Glaucoma

Purpose

This study aimed to histologically compare the status of Schlemm's canal (SC) and Schlemm's canal endothelial (SCE) cells between trabeculectomy specimens from patients with primary open-angle glaucoma (POAG) and exfoliation glaucoma (EXG).

Methods

A total of 182 eyes from 152 patients with POAG and 138 eyes from 116 patients with EXG underwent immunohistochemical staining for thrombomodulin. Equal numbers of cases were selected from both groups using propensity score matching. The following parameters were evaluated: total SC length, staining positive and negative SC length (PSC and NSC, respectively), opened and closed SC length, staining positive and opened SC length, staining positive and closed SC length, staining negative and opened SC length (NOSC), and staining negative and closed SC length.

Results

After matching for age and gender, 87 cases were selected in each group. The EXG group had significantly higher preoperative IOP and medication scores. PSC was significantly longer in the POAG group, while NSC and NOSC were longer in the EXG group. Multiple regression analysis of these 174 cases revealed that PSC was significantly shorter in the EXG group. After matching for age, gender, preoperative IOP, and medication score, 64 cases were selected in each group, and NOSC was significantly longer in the EXG group.

Conclusions

These findings suggest that in EXG, SCE loss occurs independently of background factors such as aging and medication use. The loss of SCE may have a more critical impact on IOP elevation in EXG compared to POAG.

New Biomarker Combination Related to Oxidative Stress and Inflammation in Primary Open-Angle Glaucoma

Glaucoma is a multifactorial neurodegenerative disease and the second leading cause of blindness. Detection of clinically relevant biomarkers would aid better diagnoses and monitoring during treatment. In glaucoma, the protein composition of aqueous humor (AH) is relevant for the discovery of biomarkers. This study analyzes AH protein concentrations of putative biomarkers in patients with primary open-angle glaucoma (POAG) compared to a control group. Biomarkers were selected from known oxidative-stress and inflammatory pathways. Osteopontin (OPN), matrix metalloproteinase 9 (MMP-9), tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), and interleukin-10 (IL-10) were measured using the ELISA technique. Thirty-two patients were recruited to the study, including sixteen control and sixteen glaucoma patients. The glaucoma group consisted of patients diagnosed with glaucoma. In both groups, the aqueous humor sample was obtained during cataract surgery. A significant increase in OPN, MMP-9, TNF-alpha, and IL-10 was observed in the POAG aqueous humor, compared to the control group (p < 0.05). Of note, the AH of POAG patients contained 5.6 ± 1.2-fold more OPN compared to that of control patients. Different expression profiles of oxidative stress-related and inflammatory biomarkers were observed between patients with POAG and controls. This confirms the reported involvement of inflammatory and oxidative stress pathways in POAG pathophysiology. In the future, several, targeted AH proteins may be used to generate a potential biomarker expression profile of this disease, aiding diagnoses and disease progression monitoring. This approach highlights the importance of biomarkers in the future. Biomarkers provide a way to measure disease progression and response to treatment. In the future, biomarkers will play a more critical role in the toolkit of ophthalmology healthcare professionals as the field moves towards personalized medicine and precision healthcare.

Significance of Singlet Oxygen Molecule in Pathologies

Reactive oxygen species, including singlet oxygen, play an important role in the onset and progression of disease, as well as in aging. Singlet oxygen can be formed non-enzymatically by chemical, photochemical, and electron transfer reactions, or as a byproduct of endogenous enzymatic reactions in phagocytosis during inflammation. The imbalance of antioxidant enzymes and antioxidant networks with the generation of singlet oxygen increases oxidative stress, resulting in the undesirable oxidation and modification of biomolecules, such as proteins, DNA, and lipids. This review describes the molecular mechanisms of singlet oxygen production in vivo and methods for the evaluation of damage induced by singlet oxygen. The involvement of singlet oxygen in the pathogenesis of skin and eye diseases is also discussed from the biomolecular perspective. We also present our findings on lipid oxidation products derived from singlet oxygen-mediated oxidation in glaucoma, early diabetes patients, and a mouse model of bronchial asthma. Even in these diseases, oxidation products due to singlet oxygen have not been measured clinically. This review discusses their potential as biomarkers for diagnosis. Recent developments in singlet oxygen scavengers such as carotenoids, which can be utilized to prevent the onset and progression of disease, are also described.