The association between serum uric acid and glaucoma severity in primary angle closure glaucoma: a retrospective case-control study

Analysis of uric acid and high-density lipoprotein levels in refractory posner-schlossman syndrome patients: a matched case-control study by the propensity score

BACKGROUND

Recent studies have indicated that oxidative stress is a crucial pathophysiological process in glaucoma. We hypothesized that Posner-Schlossman syndrome (PSS) is a vascular inflammation in the ciliary body due to oxidative stress and endothelial dysfunction. Thus, we investigated serum uric acid (UA) and lipid levels in patients with refractory PSS with the aim of providing basic evidence for the mechanism of PSS.

METHODS

This is a retrospective, case-control study. A total of 81 refractory PSS and 409 control participants were included in this study. Clinical and laboratory characteristics were reviewed using an electronic medical system. Propensity score-matched (PSM) analysis was performed to reduce demographic differences. The t-test, Mann-Whitney U test, and χ2 test were used to assess the differences between the PSS and control groups. Logistic regression analysis was used to identify the predictors of PSS.

RESULTS

The higher serum UA (364.14 ± 98.72µmol/L vs. 322.38 ± 72.09µmol/L), higher low-density lipoprotein (LDL) / High-density lipoprotein (HDL) ratio (2.50 ± 0.97 vs. 1.95 ± 0.72) and lower HDL (1.29 ± 0.32 mmol/L vs. 1.59 ± 0.38 mmol/L) can be noticed in refractory PSS than control group. Logistics regression identified UA > 420 µmol/L (OR = 4.461) and the HDL < 1.03 mmol/L (OR = 3.896) were the independent risk factors for refractory PSS.

CONCLUSIONS

Increasing serum UA and decreasing HDL levels were positively correlated with the incidence risk of refractory PSS. Further prospective longitudinal studies and animal models are needed.

Glaucoma and the Human Microbiome

PURPOSE OF REVIEW

To explore a view of the human microbiome as an interconnected, functional, dynamic system that may be linked to the pathogenesis and progression of glaucoma.

METHODS

A literature review was undertaken that included publications from 1966 to 2023.

RESULTS

Bacterial lipopolysaccharides (LPS) activate toll-like receptors (TLR) and mediate the human immune response. The LPS-TLR4 pathway is a potential avenue for the ocular, gut, and oral microbiomes to interface and/or influence ocular disease. Studies of gut dysbiosis have shown that alterations in the healthy microbiota can predispose the host to immune-mediated inflammatory and neurodegenerative conditions, while oral and ocular surface dysbiosis has been correlated with glaucoma. While developmental exposure to commensal microflora has shown to be necessary for the autoimmune and neurodegenerative responses to elevated intraocular pressure to take place, commensal bacterial products like short-chain fatty acids have regulatory effects protective against glaucoma.

SUMMARY

Alterations to human microbiotas have been associated with changes in intestinal permeability, gene regulation, immune cell differentiation, and neural functioning, which may predispose the host to glaucoma. Select microbes have been highlighted for their potential contributions to glaucoma disease progression or protection, raising the potential for microbiota-based treatment modalities. Current topical glaucoma treatments may disrupt the ocular surface microbiota, potentially having ramifications on host health. Further study of the relationships between human microbiome and glaucoma is needed.

Association between primary angle closure glaucoma and uric acid levels in serum and aqueous humor

Purpose

To evaluate abnormalities in serum and aqueous humor uric acid (UA) levels in primary angle closure glaucoma (PACG).

Methods

Patients with PACG and age-similar and gender-similar controls (patients scheduled for cataract extraction) were enrolled prospectively. Serum UA levels were determined by enzymatic colorimetry; aqueous humor UA levels by Enzyme-Linked ImmunoSorbent Assay. A t-test was used to compare UA levels between PACG patients and controls, with one-way ANOVA used to compare levels across PACG subgroups with differing disease severity. Comparisons between PACG patients and controls were adjusted for systemic and ocular confounding factors using binary logistic regression.

Results

In all, 131 PACG patients and 112 controls were included. The serum UA level was 266 ± 69 μmol/L in the PACG group and 269 ± 73 μmol/L in the control group (p = 0.71). The aqueous humor UA level was 35.4 ± 8.2 μmol/L in the PACG group and 53.9 ± 18.6 μmol/L in the control group (p < 0.001). This difference remained significant after adjusting for age, gender, systolic blood pressure, diastolic blood pressure, body mass index, axial length, central corneal thickness, anterior chamber depth, lens thickness, white-to-white distance, corneal endothelial cell density, and serum UA level (odds ratio: 0.88, 95 % confidence interval: 0.83-0.93, p < 0.001).

Conclusion

Aqueous humor UA levels differ between PACG patients and controls, but serum UA levels do not. This indicates that local UA plays a role in the pathogenesis of PACG, but systemic UA does not.

Platelet-to-lymphocyte ratio and lymphocyte-to-monocyte ratio in glaucoma: a meta-analysis

Aim: To explore the association between two systemic inflammation markers, platelet-to-lymphocyte ratio (PLR) and lymphocyte-to-monocyte ratio (LMR), and glaucoma. Materials & methods: The authors searched PubMed, Embase and the Cochrane Library for eligible studies comparing PLR and LMR levels in glaucoma patients and healthy controls. Results: Analysis revealed that glaucoma patients exhibited significantly elevated PLR levels and reduced LMR compared with nonglaucoma controls. These findings were consistent across various glaucoma types, with the exception of secondary glaucoma, where the association with PLR was less significant. Conclusion: The authors found PLR and LMR to be potential valuable biomarkers for glaucoma identification and progression monitoring. These findings highlight the role of systemic inflammation in glaucoma pathogenesis.

Risk Factors for Primary Angle-closure Glaucoma: A Systematic Review and Meta-analysis of 45 Studies

SIGNIFICANCE

This study summarized primary angle-closure glaucoma (PACG)-related factors across different dimensions.

OBJECTIVES

This review aimed at systematically summarizing the associated factors of PACG in published literatures.

METHODS

A systematic review and meta-analysis were conducted by searching the electronic databases including PubMed, EMBASE, and Web of Science from their inception to November 2021. The pooled risk estimates of continuous and categorical variables were calculated using weighted mean difference (WMD) and odds ratio (OR; 95% confidence intervals [CIs]), respectively.

RESULTS

We included 45 studies in this review. In the meta-analysis, intraocular pressure (WMD, 3.13; 95% CI, 2.37 to 3.89), anterior chamber depth (WMD, -0.52; 95% CI, -0.70 to -0.34), axial length (WMD, -0.77; 95% CI, -1.26 to -0.28), retinal nerve fiber layer (WMD, -21.23; 95% CI, -30.21 to -12.25), and spherical equivalent (WMD, 1.02; 95% CI, 0.66 to 1.38) were the most common ophthalmic anatomic factors, and lower body weight (WMD, -3.65; 95% CI, -6.48 to -0.82) was the most significant general morphological indicators. The presence of cataract (OR, 3.77; 95% CI, 3.46 to 4.11) and hyperlipidemia (OR, 1.10; 95% CI, 1.02 to 1.20) were significantly associated with PACG. Increased level of triglyceride (WMD, 0.17; 95% CI, 0.06 to 0.27) was associated with PACG. In addition, an association between short-term antidepressant exposure (OR, 1.36; 95% CI, 1.08 to 1.70) and acute angle-closure glaucoma was observed.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

This review identified a few consistent factors related to PACG, providing important information for primary care physicians, general ophthalmologists, and public health professionals to counsel their patients on PACG risks.

Is the clinical course of non-arteritic ischemic optic neuropathy associated with oxidative damage and the dynamics of the antioxidant response?

PURPOSE

Oxidative stress is known to be a decisive factor in the wide etiopathogenesis of optic neuropathy. This study aimed to comprehensively evaluate the interaction of optic neuropathy's clinical course with systemic oxidative damage and antioxidant response dynamics in a large series.

METHODS

This case-controlled clinical study included 33 non-arteritic anterior ischemic optic neuropathy (NAION) patients and 32 healthy individuals. Extensive systemic oxidation profiles were statistically compared between the two groups, and correlations between the clinical and biochemical data in the study group were analyzed.

RESULTS

Vitamin E and malondialdehyde (MDA) levels were significantly higher in the study group. Significant correlations were observed in the analyses between clinical findings and oxidative stress parameters. Correlations between vitamin E and intraocular pressure (IOP), between B12 and cup-to-disk ratio (c/d), between antioxidant glutathione and superoxide dismutase (SOD) enzyme systems, and between uric acid (UA) and age were found to be very significant. As significant correlations were found in either clinical and biochemical data or in oxidative stress parameters, correlations between vitamin E and cholesterol, MDA were found to be very significant.

CONCLUSIONS

This study not only supplies significant information regarding oxidative damage and antioxidant response in NAION, but also points out the specific interactions of neuromodulators, like vitamin E, in intracellular signaling pathways and regulation mechanisms. A better reading of these connections may help improve diagnosis, follow-ups and treatment criteria and strategies.

Uric acid and glaucoma: a systematic review and meta-analysis

Background

Glaucoma, the leading cause of irreversible blindness, is a common disorder that contributes to gradual optic nerve degeneration. The beneficial impacts of uric acid (UA) have been reported in some neurodegenerative conditions such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. But the results of current studies about the association between serum UA level and glaucoma are conflicting. The present meta-analysis was conducted to provide a better understanding of the association between serum UA level and glaucoma.

Methods

We searched the databases of PubMed, Scopus, Web of Science, and Google Scholar systematically until November 20, 2022 to identify case-control studies, comparing the serum UA concentrations of the patients with glaucoma and controls. The mean ± standard division difference was used to assess the difference in serum UA concentrations between the glaucoma patients and controls.

Results

Six studies involving 1,221 glaucoma patients and 1,342 control group were included in the present meta-analysis. This meta-analysis using a random effect model indicated that the mean UA level in glaucoma patients was 0.13 (I2 = 91.92%, 95% CI = -0.42 to 0.68) higher than the controls; however, it was not statistically significant.

Conclusions

Our findings provide evidence that glaucoma patients have a higher serum UA level compared to the controls, but this difference is not statistically significant. Prospective studies are needed to determine the possible association between increased UA and glaucoma pathogenesis.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022364055, identifier: CRD42022364055.

Association between Serum Total Bilirubin Level and Patients with Primary Open-Angle Glaucoma in China: A Cross-Sectional, Case-Control Study

Objective

To investigate the relationship between peripheral blood total bilirubin (TBIL) levels and the risk of primary open-angle glaucoma (POAG).

Methods

This study was a cross-sectional, case-control study design. Between April 2021 and January 2022, 198 POAG patients and 205 healthy subjects were recruited from the EENT Hospital of Fudan University. Their clinical information (intraocular pressure, central corneal thickness, vertical cup-disk ratios (VCDR), and axial length) and demographic data were collected. Serum levels of TBIL were measured in enzymes using a Roche C702 biochemical analyzer. The POAG subgroups were classified by gender and VCDR: mild (VCDR ≤ 0.64), moderate (VCDR ≤ 0.85), and severe (VCDR > 0.85). Univariate and multivariate logistic regression analyses were performed.

Results

The level of TBIL (11.58 ± 5.16 μmol/L) in the POAG group was higher than that in the control group (10.18 ± 3.38 μmol/L; p < 0.05). In the male subgroup, TBIL was also significantly higher than in the normal control group; TBIL levels were lower in the mild subgroup (10.82 ± 4.48 μmol/L), followed by the moderate subgroup (12.00 ± 5.55 μmol/L) and the severe subgroup (14.47 ± 5.45 μmol/L). The results of the multivariate logistic regression analysis showed that high TBIL levels were a risk factor for male POAG, at 1.126 (95% CI 1.009-1.256). Pearson's analysis revealed that TBIL was positively correlated with intraocular pressure (r = 0.134, p = 0.012), VCDR (r = 0.142, p = 0.046), anterior chamber depth (r = 0.190, p = 0.014), and axial length (r = 0.179, p = 0.019) in the patients. However, no statistical difference (p < 0.05) was observed in the female patients with POAG.

Conclusion

The results showed that high levels of TBIL may be related to the pathogenesis of POAG and that the severity of the disease is positively correlated, especially in male patients.

Co-occurrence of chronic kidney disease and glaucoma: Epidemiology and etiological mechanisms

As the histology, physiology, and pathophysiology of eyes and kidneys show substantial overlap, it has been suggested that eye and kidney diseases, such as glaucoma and chronic kidney disease (CKD), may be closely interlinked. We review the relationship between CKD and various subtypes of glaucoma, including primary open-angle glaucoma, primary angle- closure glaucoma, normal tension glaucoma, pseudoexfoliation syndrome, and several glaucoma endophenotypes. We also discuss the underlying pathogenic mechanisms and common risk factors for CKD and glaucoma, including atherosclerosis, the renin-angiotensin system, genes and genetic polymorphisms, vitamin D deficiency, and erythropoietin. The prevalence of glaucoma appears elevated in CKD patients, and vice versa, and the literature points to many intriguing associations; however, the associations are not always confirmed, and sometimes apparently opposite observations are reported. Glaucoma and CKD are complex diseases, and their mutual influence is only partially understood.

Diet, Oxidative Stress, and Blood Serum Nutrients in Various Types of Glaucoma: A Systematic Review

Glaucoma is one of the most common causes of irreversible vision loss worldwide. It is an insidious disease with a multifactorial pathogenesis. Despite progress in treatment methods, prevention and lifestyle modifications may be useful in slowing the progression of this disease. This systematic review aimed to evaluate the influence of diet, oxidative stress, and disturbances in blood serum levels of nutrients on the incidence and severity of glaucoma based on scientific reports on the role of nutrition in the pathogenesis and course of glaucoma. This paper presents an analysis of the above issues; however, further research is required to develop this topic. Future clinical trials are needed to assess the influence of nutrition and to develop nutritional management strategies for patients with glaucoma.

Damage-Associated Molecular Patterns (DAMPs) in Retinal Disorders

Damage-associated molecular patterns (DAMPs) are endogenous danger molecules released from the extracellular and intracellular space of damaged tissue or dead cells. Recent evidence indicates that DAMPs are associated with the sterile inflammation caused by aging, increased ocular pressure, high glucose, oxidative stress, ischemia, mechanical trauma, stress, or environmental conditions, in retinal diseases. DAMPs activate the innate immune system, suggesting their role to be protective, but may promote pathological inflammation and angiogenesis in response to the chronic insult or injury. DAMPs are recognized by specialized innate immune receptors, such as receptors for advanced glycation end products (RAGE), toll-like receptors (TLRs) and the NOD-like receptor family (NLRs), and purine receptor 7 (P2X7), in systemic diseases. However, studies describing the role of DAMPs in retinal disorders are meager. Here, we extensively reviewed the role of DAMPs in retinal disorders, including endophthalmitis, uveitis, glaucoma, ocular cancer, ischemic retinopathies, diabetic retinopathy, age-related macular degeneration, rhegmatogenous retinal detachment, proliferative vitreoretinopathy, and inherited retinal disorders. Finally, we discussed DAMPs as biomarkers, therapeutic targets, and therapeutic agents for retinal disorders.

The Pathomechanism, Antioxidant Biomarkers, and Treatment of Oxidative Stress-Related Eye Diseases

Oxidative stress is an important pathomechanism found in numerous ocular degenerative diseases. To provide a better understanding of the mechanism and treatment of oxidant/antioxidant imbalance-induced ocular diseases, this article summarizes and provides updates on the relevant research. We review the oxidative damage (e.g., lipid peroxidation, DNA lesions, autophagy, and apoptosis) that occurs in different areas of the eye (e.g., cornea, anterior chamber, lens, retina, and optic nerve). We then introduce the antioxidant mechanisms present in the eye, as well as the ocular diseases that occur as a result of antioxidant imbalances (e.g., keratoconus, cataracts, age-related macular degeneration, and glaucoma), the relevant antioxidant biomarkers, and the potential of predictive diagnostics. Finally, we discuss natural antioxidant therapies for oxidative stress-related ocular diseases.

Protein Biomarkers in Glaucoma: A Review

Glaucoma is a multifactorial disease. Early diagnosis of this disease can support treatment and reduce the effects of pathophysiological processes. A significant problem in the diagnosis of glaucoma is limited access to the tested material. Therefore, intensive research is underway to develop biomarkers for fast, noninvasive, and reliable testing. Biomarkers indicated in the formation of glaucoma include chemical compounds from different chemical groups, such as proteins, sugars, and lipids. This review summarizes our knowledge about protein and/or their protein-like derived biomarkers used for glaucoma diagnosis since 2000. The described possibilities resulting from a biomarker search may contribute to identifying a group of compounds strongly correlated with glaucoma development. Such a find would be of great importance in the diagnosis and treatment of this disorder, as current screening techniques have low sensitivity and are unable to diagnose early primary open-angle glaucoma.

Gout and open-angle glaucoma risk in a veteran population

PURPOSE

A history of gout, arthritis due to hyperuricemia, has been associated with decreased risk for neurodegenerative diseases such as Parkinson's disease. We performed a population-based case-control study in the US Department of Veterans Affairs (VA) medical centers nationwide to assess if gout or hyperuricemia is similarly associated with the ocular neurodegenerative condition glaucoma.

METHODS

We used ICD-9 codes to identify a nationwide cohort of patients examined at VA healthcare eye clinics between 2000 and 2015 with a diagnosis of open-angle glaucoma (OAG) or of glaucoma suspect. We used incidence density matching to choose controls. We used multivariable logistic regression to examine associations between a history of gout and uric acid (UA) levels on relative risk of OAG or glaucoma suspect.

RESULTS

There were 1,144,428 OAG or glaucoma suspect cases and 1,144,428 matched controls. Veterans with a history of gout had a small significant decreased risk of OAG compared to controls (OR_{adjusted(adj)} = 0.985, 95% CI: 0.974-0.996). Treated gout was similarly associated with small decreased risk (OR_adj = 0.963, 95% CI: 0.950-0.976). A small subset of patients (11.9% of cases and 13.2% of controls) had UA labs available; veterans with the highest median UA levels (> 7.29 mg/dL) did not have statistically significant differences in relative OAG risk (OR_adj = 1.014, 95% CI: 0.991-1.036).

CONCLUSION

Prospective research in other cohorts is needed to confirm our findings in veterans suggesting a history of gout is associated with a small decreased relative risk of glaucoma.

Increased risk of glaucoma amongst new-onset gout patients aged 20-39 years: A nationwide population-based cohort study in Taiwan

OBJECTIVES

To provide epidemiologic evidence of whether gout increases the risk of new-onset glaucoma.

METHODS

We conducted a 13-year nationwide, population-based, retrospective cohort study to examine the association between the history of gout and risk of glaucoma by using the Longitudinal Health Insurance Database (LHID) of Taiwan. The gout cohort included 52 943 patients with newly diagnosed gout who were recruited between 2000 and 2012. Each patient was propensity score matching with 1:1 person without gout from the LHID. To determine glaucoma occurrence, the study population was followed up until the end of 2013. Cumulative incidence, hazard ratios (HRs), and 95% confidence intervals (CIs) were calculated after adjusting for age, sex, comorbidities, and ever ophthalmic visit. A Cox proportional hazard model was used to analyse the association between gout and incidence of glaucoma amongst patients with different potential risks.

RESULTS

The adjusted HR for newly diagnosed glaucoma in the gout cohort was 1.00 (95% CI = 0.93-1.07, P = .931), compared with the non-gout cohort. Stratified subgroup analysis revealed that the HRs of glaucoma were 1.36 (95% CI = 1.09-1.70, P = .007), 0.99 (95% CI = 0.87-1.12, P = .871), and 0.95 (95% CI = 0.87-1.03, P = .235) in patients with gout aged 20-39, 40-54, and ≥55 years, respectively (P for interaction = .011).

CONCLUSION

This nationwide population-based cohort study revealed that gout patients in the age group 20-39 years had a higher risk of glaucoma than non-gout controls.

Association of serum uric acid levels with COVID-19 severity

AIMS

Hyperuricemia has attracted increasing attention. However, limited concern has been paid to the potential dangers of lowering serum uric acid (SUA). We observed lower levels of SUA in patients with COVID-19. Therefore, we aim to explore whether patients with COVID-19 had SUA lower than normal and the relationship of SUA and the severity of COVID-19.

METHODS

This was a case-control study based on 91 cases with COVID-19 and 273 age- and sex-matched healthy control subjects. We first compared SUA levels and uric acid/creatinine (UA/Cr) ratio between patients with COVID-19 and the healthy controls. Then, we examined the association of SUA levels and UA/Cr ratios with COVID-19 severity in COVID-19 cases only, defined according to the fifth edition of China's Diagnosis and Treatment Guidelines of COVID-19.

RESULTS

SUA levels in patients with COVID-19 were 2.59% lower, UA/Cr ratios 6.06% lower at admission compared with healthy controls. In sex stratified analysis, levels of SUA and UA/Cr were lower in male patients with COVID-19 while only level of SUA was lower in female patients with COVID-19. Moreover, SUA and UA/Cr values were 4.27 and 8.23% lower in the severe group than that in the moderate group among male COVID-19 patients. Bivariate and partial correlations analysis showed negative correlations between SUA or UA/Cr ratio and COVID-19 after adjusting for age, sex, BMI and eGFR. A multiple linear regression analysis showed that SARS-CoV-2 infection and male sex were independent risk factors associated with lower SUA levels. Male patients with COVID-19 accompanied by low SUA levels had higher risk of developing severe symptoms than those with high SUA levels (incidence rate ratio: 4.05; 95% CI:1.11, 14.72) at admission. Comparing SUA and UA/Cr ratio at three time points (admission, discharge, and follow-up), we found that male patients experienced severe symptoms had lower SUA and UA/Cr ratio levels comparing to moderate patients, but no significant difference between three time points. On the contrary, female patients had lower SUA and UA/Cr ratio at discharge than those at admission, but no significant difference of SUA and UA/Cr ratio between moderate and severe group.

CONCLUSION

Patients with COVID-19 had SUA and UA/Cr values lower than normal at admission. Male COVID-19 patients with low SUA levels had a significantly higher crude risk of developing severe symptoms than those with high SUA levels. During disease aggravation, the level of SUA gradually decreased until discharge. At the follow-up exam, the level of SUA was similar to the levels at admission.

Relationship between Oxidative Stress Biomarkers and Visual Field Progression in Patients with Primary Angle Closure Glaucoma

Purpose

To investigate the serum changes of oxidative stress markers and the relationship between these factors and visual field (VF) progression in patients with primary angle closure glaucoma (PACG).

Methods

A case-control and a prospective cohort study. A total of 94 patients with PACG and 89 normal controls were enrolled. Furthermore, 94 PACG subjects were followed up for at least two years (once every six months). All participants were evaluated for serum levels of superoxide dismutase (SOD), total antioxidant status (TAS), hydrogen peroxide (H₂O₂), malondialdehyde (MDA), glutathione peroxidase, glutathione reductase, and detailed eye and systematic examination. Binary logistic regression analysis and Cox regression analysis were performed.

Results

The serum levels of SOD and TAS in the PACG group were significantly lower than those in the control group (p < 0.001). Meanwhile, PACG subjects had significantly higher levels of MDA and H₂O₂ than the normal control subjects (p < 0.001). Serum levels of TAS (OR = 0.773, 95%CI = 0.349 − 0.714, p < 0.001), SOD (OR = 0.975, 95%CI = 0.955 − 0.995, p < 0.001), MDA (OR = 1.155, 95%CI = 1.080 − 1.235, p < 0.001), and H₂O₂ (OR = 1.216, 95%CI = 1.142 − 1.295, p < 0.001) were independent risk/protective factors for PACG. TAS levels (HR = 0.041, 95%CI = 0.008–0.218, p < 0.001), SOD levels (HR = 0.983, 95%CI = 0.971–0.994, p = 0.003), and MDA levels (HR = 1.010, 95%CI = 1.001–1.018, p = 0.015) at baseline were associated with visual field progression. Kaplan–Meier curves reveal that patients with TAS < 0.95/SOD < 143/MDA > 12 had a significantly higher percentage of PACG progression (p < 0.05).

Conclusions

Decreased levels of TAS and SOD as well as increased levels of MDA at baseline were associated with VF progression in patients with PACG. These findings suggest that oxidative stress was involved in the onset and development of PACG.

Detection of serum uric acid in primary open angle glaucoma: A pilot study

PURPOSE

To assess the association between the serum levels of uric acid (UA) and primary open-angle glaucoma (POAG).

METHODS

In this pilot study, 46 eyes of 23 patients with a clinical history of POAG and 30 eyes of 15 healthy subjects were included. All patients underwent a complete ophthalmological examination, including best corrected visual acuity (BCVA), intraocular pressure (IOP), and gonioscopy. Visual field parameters, such as mean deviation (MD) and pattern standard deviation (PSD), and optical coherence tomography (OCT) values of the optic nerve head, including retinal nerve fiber layer (RNFL) thickness and vertical cup/disc ratio (VCDR), were noted. A blood sample was collected from each subject for serum UA measurement.

RESULTS

IOP, MD, PSD, RNFL thickness, and VCDR resulted significantly different in POAG patients, when compared with controls (p < 0.05). POAG patients showed significantly lower levels of mean serum UA than healthy controls (4.00 ± 0.66 mg/dL vs 4.95 ± 0.86 mg/dL, respectively, p < 0.0001). Furthermore, severe POAG patients showed mean serum levels of UA lower than mild POAG patients (3.36 ± 0.70 mg/dL vs 4.22 ± 0.51 mg/dL, respectively, p = 0.01). Visual field and OCT parameters were statistically correlated with the mean serum levels of UA in POAG eyes (p < 0.05).

CONCLUSION

Results suggest that in POAG patients, serum UA levels may be decreased and correlated with visual field and OCT parameters worsening. Further larger multi-center prospective studies are necessary to confirm our findings and establish the role of UA in glaucoma.

Decreased Serum Levels of Complement C3 Reflect Complement System Dysregulation in Patients With Primary Open-angle Glaucoma: Results From a Pilot Study

PURPOSE

To evaluate the serum complement component (C)3 concentration in patients with primary open-angle glaucoma (POAG) and to investigate the association between C3 levels and POAG severity.

MATERIALS AND METHODS

This study enrolled 190 consecutive POAG patients and 204 normal control subjects. A detailed eye and systematic examination, including intraocular pressure, gonioscopy, fundus photography, A-scan ultrasound, visual field testing, electrocardiograms, x-rays, liver function, renal function, infectious disease, etc., and measurement of serum C3 concentration by immunoturbidimetry, was performed. The subgroups were classified according to age (17 to 29, 30 to 49, 50 to 69, 70+ y), sex, and visual field: mild (MD≤6 dB), moderate (6 dB<MD≤12 dB), and severe (MD>12 dB) glaucoma.

RESULTS

The serum C3 level of the POAG (95.63±17.71 mg/dL) was ∼20.93% lower than that of the control group (115.65±22.19 mg/dL) (P<0.001). A similar result was observed when serum levels of C3 were compared between the POAG and control groups with respect to age and sex. The mean serum C3 level was lowest in the severe POAG group (85.18±19.62 mg/dL), followed by the moderate POAG group (96.62±12.63 mg/dL) and the mild POAG group (110.44±14.89 mg/dL) (P<0.001). Multiple logistic regression analyses revealed a significant correlation between the C3 levels and the vertical cup-disc ratio (B=-0.373, P=0.026), C3 levels and MD (B=-0.546, P=0.001). Logistic regression analyses revealed that serum C3 levels were associated (odds ratio=0.939, 95% CI=0.901-0.979, P=0.003) with severity of POAG.

CONCLUSIONS

The POAG patients had decreased C3 levels, which were further negatively associated with POAG severity, suggesting the involvement of C3 in the pathomechanisms of POAG.

Relationship between ocular biometry and severity of primary angle-closure glaucoma: relevance for predictive, preventive, and personalized medicine

Background

Several ocular factors have been identified for primary angle-closure glaucoma (PACG), such as a small cornea, elevated intraocular pressure (IOP), shallow anterior chamber, and short axial length (AL). However, the relationship between the severity of PACG and various ocular parameters [IOP, anterior chamber depth, AL, central corneal thickness] is not fully understood.

Methods

A 7-year cross-sectional study. A total of 2254 eyes of 1312 PACG patients (females = 856 [1479 eyes] and males = 456 [775 eyes]) were included. A detailed eye examination was performed. The participants were categorized into gender subgroups followed by subdivision into three different severity groups according to their mean deviation (MD) of the visual fields results as follows: mild (MD ≤ 6 dB), moderate (MD 6-12 dB), and severe (MD > 12 dB) PACG. The associations of ocular biometry with severity of PACG were analyzed using paired Student's t test, multivariate linear regression, and logistic regression analysis.

Results

There was a significant positive correlation between the MD and AL in the female subgroup (B = 0.663, p = 0.001, 95%CI = 1.070 to 1.255) but not in the male subgroup. Increased AL levels (mild [OR = 1], moderate [OR = 1.047, p = 0.062, 95%CI = 0.947 to 2.462], and severe [OR = 1.274, p < 0.001, 95%CI = 1.114 to 1.457]) were only associated with the severity of PACG in females. Paired Student's t tests showed that the long AL female eyes have a higher MD value than in the short AL female eyes (mean difference = 3.09, t = 6.846, p < 0.001) in the same subjects, but not in the male subgroup (p = 0.648).

Conclusions

The AL was positively and significantly related to the severity of PACG in female but not male subjects. This finding refers to the PACG pathogenesis and suggests the use of AL assessment in glaucoma monitoring, diagnosis, and progression. This may contribute to further development of personalized strategies in preventive medicine.

Uric Acid Provides Protective Role in Red Blood Cells by Antioxidant Defense: A Hypothetical Analysis

Uric acid (UA) is a major antioxidant molecule in the human blood, and it has been linked with cell longevity. However, it is unclear whether serum UA levels are associated with red blood cell (RBC) indexes. This cross-sectional study included 10,759 Chinese subjects, recruited from the Shanghai Xuhui Central Hospital from January 2014 to December 2017. The participants were categorized into gender groups and then further divided into three different subgroups according to their UA reference range as follows: low (male (UA < 0.202 mmol/l), female (UA < 0.143 mmol/l)), normal (male (0.417 mmol/l > UA ≥ 0.202 mmol/l), female (0.339 mmol/l > UA ≥ 0.143 mmol/l)), and high (male (UA ≥ 0.417 mmol/l), female (UA ≥ 0.339 mmol/l)). The associations of UA levels with RBC parameters were analyzed using 1-way ANOVA, Pearson correlations, and multivariate linear regression. The levels of mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, RBCs, and hemoglobin were lowest in the low UA group, followed by the normal UA group and high UA group (p < 0.001). Pearson analysis showed that there was a statistically significant correlation between UA levels with mean corpuscular hemoglobin, mean corpuscular hemoglobin concentrations, mean corpuscular volumes, RBC counts, and hemoglobin (p < 0.05). Multiple linear regression analysis suggested that there were statistically significant positive correlations between UA levels and RBC counts (B = 0.245, p < 0.001, 95% CI = 0.003 to 0.092), as well as UA levels and hemoglobin concentrations (B = 0.138, p < 0.001, 95% CI = 0.002 to 0.082). Furthermore, similar results were observed in both the male and female subgroups. The serum UA levels may be independently associated with RBC parameters, regardless of sex, and UA may protect RBCs owing to its antioxidant effect.

Association of serum uric acid levels with primary open-angle glaucoma: a 5-year case-control study

PURPOSE

It has been hypothesised that uric acid (UA) has a protective effect against oxidative damage in the central nervous system. Therefore, we investigated serum UA concentrations in patients with primary open-angle glaucoma (POAG) and explored the relationship between serum UA concentration and glaucoma severity.

METHODS

This prospective, cross-sectional, case-control study was conducted in 163 POAG patients and 103 normal controls. Clinical and demographic information was obtained from the medical data platform of the Eye & ENT Hospital of Fudan University, Shanghai, China. The POAG patients were categorised into mild [median deviation (MD) ≤ 6.00 dB], moderate (MD > 6 Db-≥12 dB) and severe (MD > 12 dB) subgroups, based on their visual field MD results.

RESULTS

The level of serum UA in the POAG group (0.321 ± 0.084 mmol/l) was approximately 12.77% lower (p < 0.001) than that of the control group (0.362 ± 0.053 mmol/l). The UA/creatinine (Cr) ratio was approximately 14.99% lower (p < 0.001) in patients with POAG (4.47 ± 1.15), compared with the control group (5.14 ± 1.05). The mean level of UA was lowest in the severe POAG group, followed by the moderate POAG group, and the mild POAG group (p < 0.001). A similar trend was observed when UA levels were compared between the POAG and control groups in males. Multivariate regression analyses showed a significant negative correlation between UA and vertical cup-disc ratio (B = -0.320, p = 0.034), and UA and MD (B = -0.441, p = 0.031) in males.

CONCLUSION

Primary open-angle glaucoma patients have lower UA levels; however, a negative association between UA levels and disease severity was evident in male patients.

Pretreatment Serum Uric Acid as an Efficient Predictor of Prognosis in Men with Laryngeal Squamous Cell Cancer: A Retrospective Cohort Study

Purpose

Uric acid (UA) is a major antioxidant molecule that has been hypothesized to have a protective effect against cancer-induced oxidative damage. The aim of the present study was to investigate whether preoperative levels of serum UA are associated with the prognosis of laryngeal squamous cell cancer (LSCC).

Methods

A total of 814 male LSCC patients (followed up for five years) and 814 normal control subjects were enrolled from January 2007 to December 2011. The rates of total mortality and cancer mortality were 23.46% and 21.36%, respectively. The prevalence of overall survival (OS), disease-free survival (DFS), and cancer-specific survival (CSS) was analysed using the Kaplan-Meier method. Univariate and multivariate Cox regression models were evaluated to identify UA as a prognostic factor.

Results

The serum UA and UA/Cr (creatinine) ratio levels were significantly reduced (P < 0.001 for both) in the LSCC group compared with the control group. The applied multivariate Cox regression model analysis found that low levels of UA and the UA/Cr ratio were independent poor prognostic factors for OS (UA (HR (95% CI) = 1.458 (1.095–1.942)), UA/Cr ratio (HR (95% CI) = 1.337 (1.004–1.780))), DFS (UA (HR (95% CI) = 1.504 (1.131–2.001)), UA/Cr ratio (HR (95% CI) = 1.376 (1.030–1.839))), and CSS (UA (HR (95% CI) = 1.494 (1.109–2.012)), UA/Cr ratio (HR (95% CI) = 1.420 (1.049–1.923))). The patients with high UA (>0.310 mmol/l) and UA/Cr ratio (>3.97) experienced five more years of OS, DFS, and CSS than did patients with low UA (<0.310 mmol/l) and UA/Cr ratio (<3.97) levels.

Conclusion

High preoperative UA serum levels were identified as an independent prognostic factor associated with improved clinical outcomes among LSCC patients.

COL11A1 Polymorphisms Are Associated with Primary Angle-Closure Glaucoma Severity

Purpose

PLEKHA7 and COL11A1 were genotyped for single-nucleotide polymorphisms (SNPs) to investigate the possible association of these two genes with primary angle-closure glaucoma (PACG) and disease severity.

Method

A total of 51 PACG cases and 51 normal controls were recruited. Twelve SNPs in the PLEKHA7 (rs216489, rs1027617, rs366590, rs11024060, rs6486330, rs11024097, and rs11024102) and COL11A1 (rs1676484, rs3753841, rs12138977, rs2126642, and rs2622848) genes were genotyped by direct Sanger sequencing. Distributions of allele frequencies and genotype frequencies in cases and controls, as well as in mild, moderate, and severe subgroups, were compared based on mean defect (MD ≤ 6.00 dB, 6 dB < MD ≤ 12 dB, and MD > 12 dB were considered mild, moderate, and severe, respectively). Independent Student's t-tests and chi-square tests were used to compare characteristics of PACG cases and controls. Chi-square tests were used to compare the distribution of allele frequencies in cases and controls and in MD-based subgroups with various degrees of glaucoma severity. Binary logistic regression was used to compare the distribution of genotype frequencies and calculate odds ratios (OR) with confidence intervals (CI).

Result

Three of the 12 SNPs in COL11A1, rs1676486 (P=0.026, OR = 2.089, 95% CI = 1.092–3.996), rs3753841 (P=0.036, OR = 1.886, 95% CI = 1.038–3.426), and rs12138977 (P=0.024, OR = 2.133, 95% CI = 1.104–4.123) were found to have a significant association with PACG. Furthermore, in the subgroup analysis, rs1676486 (P=0.018, OR = 2.416, 95% CI = 1.284–4.544; P=0.011, OR = 2.119, 95% CI = 1.204–3.729), rs12138977 (P=0.009, OR = 2.158, 95% CI = 1.287–3.618; P=0.006, OR = 1.962, 95% CI = 1.239–3.106), and rs3753841 (P=0.007, OR = 2.550, 95% CI = 1.344–4.839) showed statistically significant differences between moderate/severe groups and controls.

Conclusion

Our data suggested that COL11A1 rs1676484, rs3753841, and rs12138977 polymorphisms may be of value for further study as potential gene-dependent risk factors for developing PACG. Moreover, COL11A1 rs1676484 and rs12138977 polymorphisms might be associated with PACG disease severity.

Association between Pretreatment Serum Uric Acid Levels and Progression of Newly Diagnosed Primary Angle-Closure Glaucoma: A Prospective Cohort Study

Purpose

Increased evidence reveals that uric acid (UA) may have an important neuroprotective effect through its antioxidant properties. The aim of the present study was to investigate the relationship between pretreatment serum UA levels and the progression of newly diagnosed primary angle-closure glaucoma (PACG).

Methods

This prospective observational cohort study included 64 patients with newly diagnosed PACG who were followed up for a mean period of 12.77 months (range: 3–28 months). All subjects underwent a complete ophthalmological examination during the baseline and final follow-up visits, together with the acquisition of blood samples for UA measurements. During the follow-up period, the progression of PACG was defined as a clinical diagnosis of medically uncontrolled intraocular pressure and a loss of visual field with a mean deviation of >1 dB/year. Univariable and multivariable Cox regression models were used to investigate the association between baseline serum UA levels and the progression of PACG. The cumulative probability of progression of glaucoma was analyzed using the Kaplan-Meier method.

Results

During follow-up, 32 subjects were defined as progressive PACG, among whom baseline UA values were significantly higher in nonprogressing subjects than in progressing subjects (0.314 ± 0.069 mmol/l versus [vs.] 0.258 ± 0.069 mmol/l, respectively; P = 0.002). Similar results were also observed in male and female subgroups (P < 0.05). In a multivariable model, a decreased baseline serum UA level was associated with an increased risk for progressing PACG: both in male (hazard ratio [HR] 6.088 [95% confidence interval (CI) 1.163–31.8638]; P = 0.032) and female subjects (HR 3.565 [95% CI 1.131–11.236]; P = 0.030). Subjects with high UA levels demonstrated higher cumulative probabilities of nonprogressing PACG than those with low UA levels (male [16.67% vs. 80.00%; P = 0.0084] and female [29.41% vs. 68.00%; P = 0.0182]).

Conclusion

An association between high baseline serum UA levels and a decreased risk for progressing PACG was found. This primary finding suggests that high serum UA levels may have a protective role against PACG and could slow disease progression.

Effect of Repeated Freeze-Thaw on Serum Biomarkers Associated with Eye Disease

Background

Serum biomarkers are associated with eye diseases, which results in the need for cryopreservation of serum samples. However, the effect on serum biomarker levels of repeatedly freezing and thawing remains poorly understood. The aim of this study was to evaluate the effects of repeated freeze-thaw on the serum levels of the protein, complement C3c (C3c), the micromolecule, uric acid (UA), and the enzyme, angiotensin-converting enzyme (ACE).

Material/Methods

Serum samples were obtained from 50 patients who attended an ophthalmic outpatient department. Following baseline measurements, the serum samples from each subject were divided into aliquots and stored at −80°C for further analysis, following between one to six freeze-thaw cycles. The serum levels of C3c, UA, and ACE were measured immediately after the stored serum samples were thawed.

Results

The serum level of C3c was significantly changed after the first freeze-thaw cycle (p<0.05), and a significant alteration in serum ACE levels occurred after the third freeze-thaw cycle (p<0.05). The serum UA level remained unchanged after all freeze-thaw cycles. Repeated freeze-thaw cycles significantly increased the serum levels of C3c and decreased the serum levels of ACE. The serum levels of C3c, UA, and ACE, respectively were significantly correlated (p<0.001), while the correlation coefficient for C3c and UA were improved when compared with ACE.

Conclusions

Repeated freeze-thaw can have variable effects on the serum levels of biomarkers, C3c, UA and ACE, which supports the need for quality control of cryopreserved serum for biomarker evaluation.

Association between coagulation function and patients with primary angle closure glaucoma: a 5-year retrospective case-control study

OBJECTIVE

To evaluate the association between coagulation function and patients with primary angle closure glaucoma (PACG).

DESIGN

A retrospective, hospital-based, case-control study.

SETTING

Shanghai, China.

PARTICIPANTS

A total of 1778 subjects were recruited from the Eye & ENT Hospital of Fudan University from January 2010 to December 2015, including patients with PACG (male=296; female=569) and control subjects (male=290; female=623).

OUTCOME MEASURES

Sociodemographic data and clinical data were collected. The one-way analysis of variance test was used to compare the levels of laboratory parameters among the mild, moderate and severe PACG groups. Multivariate logistic regression analyses were performed to identify the independent risk factors for PACG. The nomogram was constructed based on the logistic regression model using the R project for statistical computing (R V.3.3.2).

RESULTS

The activated partial thromboplastin time (APTT) of the PACG group was approximately 4% shorter (p<0.001) than that of the control group. The prothrombin time (PT) was approximately 2.40% shorter (p<0.001) in patients with PACG compared with the control group. The thrombin time was also approximately 2.14% shorter (p<0.001) in patients with PACG compared with the control group. The level of D-dimer was significantly higher (p=0.042) in patients with PACG. Moreover, the mean platelet volume (MPV) of the PACG group was significantly higher (p=0.013) than that of the control group. A similar trend was observed when coagulation parameters were compared between the PACG and control groups with respect to gender and/or age. Multiple logistic regression analyses revealed that APTT (OR=1.032, 95% CI 1.000 to 1.026), PT (OR=1.249, 95% CI 1.071 to 1.457) and MPV (OR=1.185, 95% CI 1.081 to 1.299) were independently associated with PACG.

CONCLUSION

Patients with PACG had a shorter coagulation time. Our results suggest that coagulation function is significantly associated with patients with PACG and may play an important role in the onset and development of PACG.

The diagnostic value of white blood cell, neutrophil, neutrophil-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio in patients with primary angle closure glaucoma

Objective

Inflammatory mechanisms may have a role in the pathogenesis of primary angle closure glaucoma (PACG). The objective of this study was to investigate the diagnostic value of white blood cell (WBC), neutrophil, neutrophil to lymphocyte ratio (NLR), and lymphocyte to monocyte ratio (LMR) in patients with PACG and its association with glaucoma severity.

Method

The study was retrospectively assessed in 771 consecutive PACG patients and 770 control subjects, laboratory parameters and clinical parameters were obtained from a medical data platform. Patients were divided into three groups with different severity based on perimetry, i.e. mild (mean deviation (MD) ≤6.00 dB), moderate (12 dB≥ MD>6 dB) and severe (MD>12 dB). We developed a nomogram to specifically identify individual patient’s risk.

Results

The mean levels of neutrophil, NLR and WBC was higher in PACG than control group, and lowest in the mild PACG group, followed by moderate PACG and severe PACG (p<0.05). The AUROC value of NLR and LMR was found to be 0.719, 0.699, respectively. Multiple linear regressions showed that there was a significant correlation between WBC and MD (B=0.151, p<0.001), neutrophil and MD (B=0.143, p=0.003), NLR and MD (B=0.144, p=0.001), LMR and MD (B=-0.100, p=0.034). Logistic regression analyses revealed that WBC (OR=1.208, 95%CI=1.179-1.238), neutrophil (OR=1.598, 95%CI=1.541-1.656), NLR (OR=2.313, 95%CI=2.200-2.431), and LMR (OR=0.682, 95%CI=0.666-0.699) were associated with PACG.

Conclusion

Our study suggested that WBC, neutrophil, NLR, and LMR was related with PACG, and NLR and LMR may be useful as biomarkers.