MMP expression in leaking filtering blebs and tears after glaucoma filtering surgery

Clinical Tear Fluid Proteomics—A Novel Tool in Glaucoma Research

Tear fluid forms the outermost layer of the ocular surface and its characteristics and composition have been connected to various ocular surface diseases. As tear proteomics enables the non-invasive investigation of protein levels in the tear fluid, it has become an increasingly popular approach in ocular surface and systemic disease studies. Glaucoma, which is a set of multifactorial diseases affecting mainly the optic nerve and retinal ganglion cells, has also been studied using tear proteomics. In this condition, the complete set of pathophysiological changes occurring in the eye is not yet fully understood, and biomarkers for early diagnosis and accurate treatment selection are needed. More in-depth analyses of glaucoma tear proteomics have started to emerge only more recently with the implementation of LC-MS/MS and other modern technologies. The aim of this review was to examine the published data of the tear protein changes occurring during glaucoma, its topical treatment, and surgical interventions.

Genetic susceptibility to high myopia in Han Chinese population

High myopia is a common ocular genetic disease in the world. The study sought to investigate the effect of the Insulin-like growth factor-1 (IGF-1) and Matrix metalloproteinase-9 (MMP-9) genes polymorphisms on high myopia in a Han population of China. This study recruited 216 unrelated Han Chinese subjects, including 103 cases with high myopia and 113 controls. Four tagging single nucleotide polymorphisms (SNPs) of IGF-1 and MMP-9 genes were genotyped using the Sequenom MassARRAY method. The chi-square test showed that the family history was significantly correlated with myopia. The SNP genotypes were all in Hardy–Weinberg equilibrium (P > 0.05). Among the four SNPs, there were statistically significant differences in the genotype and allele frequencies of rs2236416 between the groups (P = 0.024). The significant associations of rs2236416 between cases and controls also appeared after Bonferroni multiple correction (P = 0.024). Then, there were significant differences in the genotypes dominant model and codominant model of rs2236416 between groups (P = 0.007 and P = 0.004, respectively). rs5742632 showed a significant difference between the cases and the controls in the recessive model (P = 0.037). Our findings indicated that rs2236416 of MMP-9 was associated with myopia in the population. The result suggested MMP-9 gene locus may play a role in myopia.

Association between MMP-2 gene polymorphism and cataract susceptibility: A protocol for systematic review and meta-analysis

BACKGROUND

Matrix metalloproteinase-2 (MMP-2) polymorphisms have been considered as risk factors of cataracts, but the results still remain controversial. In this study, we have performed a systematic meta-analysis to evaluate the association between MMP-2 polymorphisms and cataract risks.

METHODS

Published literature was retrieved from Wanfang, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, Chongqing VIP Chinese Science and Technology Periodical Database, PubMed, Embase, and Web of Science databases. The case-control studies that explored the association between MMP-2 polymorphisms and cataract risks were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using random- or fixed-effects model.

RESULTS

This study could provide high-quality and evidence-based medical evidence for the correlation between MMP-2 polymorphisms and cataract risks.

CONCLUSION

The study could provide updated evidence for the evaluation of the relationship between MMP-2 polymorphism and cataract risk.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also will not involve endangering participant rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/KU9NE.

Comparison of the Efficacy and Safety of Trabeculectomy with Mitomycin C According to Concentration: A Prospective Randomized Clinical Trial

(1) Background: Mitomycin C (MMC) is commonly used during trabeculectomy. However, there is no consensus on which concentration should be used. We aimed to compare the efficacy and safety of 0.2 mg/mL and 0.4 mg/mL of MMC in eyes undergoing trabeculectomy. (2) Methods: Thirty-six eyes (36 glaucoma patients) were randomized to undergo a trabeculectomy with 0.2 mg/mL or 0.4 mg/mL of MMC. The success rate was evaluated according to three criteria: (A) intraocular pressure (IOP) ≤ 18 mmHg and IOP reduction ≥ 20%; (B) IOP ≤ 15 mmHg and IOP reduction ≥ 25%; (C) IOP ≤ 12 mmHg and IOP reduction ≥ 30%. Cox’s proportional hazard model was used to identify the predictive factors for failure. Immunohistochemical procedures for matrix metalloproteinase (MMP) were performed on Tenon’s tissue. Bleb morphology was evaluated. Safety was assessed based on the incidence of complications. (3) Results: Of the 36 eyes, 19 underwent trabeculectomy with 0.2 mg/mL of MMC and 17 with 0.4 mg/mL. The success rates were 75%, 67%, and 47% at 6 months for criteria A, B, and C, respectively. There were no significant differences between the two groups. High MMP-9 staining and low preoperative IOP were associated with failure (hazard ratio (HR), 5.556; p = 0.033, and HR, 0.936; p = 0.033). Complications included hypotony in two eyes (6%), hyphema in one eye (3%), and choroidal detachment in one eye (3%). (4) Conclusions: Trabeculectomy with 0.2 mg/mL and 0.4 mg/mL of MMC showed similar IOP-control effects to those recorded in previous studies, along with a low rate of complications. There was no significant difference in efficacy or safety between the 0.2 mg/mL and 0.4 mg/mL MMC groups.

Cordyceps cicadae polysaccharides ameliorated renal interstitial fibrosis in diabetic nephropathy rats by repressing inflammation and modulating gut microbiota dysbiosis

Diabetic nephropathy (DN), a complication of diabetes mellitus, has been the leading cause of death in people with chronic kidney disease. This study was conducted to examine the potential health benefits of Cordyceps cicadae polysaccharides (CCP) on kidney injury and renal interstitial fibrosis that occur in DN rats. First, a DN model was established using SD rats fed with a high-fat diet for 8 weeks, then injected with STZ (35 mg/kg) intraperitoneally. The rats were then supplemented with CCP (75, 150 and 300 mg/kg) for 4 weeks. The results indicated that CCP improve insulin resistance and glucose tolerance in DN rats. Furthermore, CCP intervention significantly suppressed the inflammation, renal pathological changes and renal dysfunction, slowing down the progression of renal interstitial fibrosis. Moreover, high-throughput pyrosequencing of 16S rRNA suggested that CCP modulated the dysbiosis of gut microbiota by enhancing the relative abundance and proliferation capacity of probiotics. In vitro, CCP can markedly decrease LPS-induced inflammatory cytokine levels and TGF-β1-induced fibroblast activation. In summary, the results provided evidence that CCP exerted a beneficial effect on tubulointerstitial fibrosis in DN rats by possibly suppressing the inflammatory response and modulating gut microbiota dysbiosis, via blocking the TLR4/NF-κB and TGF-β1/Smad signaling pathway.

Tears and ocular surface disorders: Usefulness of biomarkers

INTRODUCTION

Corroborating data suggest that the analysis of tear fluid might represent an additional tool in the ophthalmological practice.

AREAS COVERED

The purpose of this review was to sum up the tear protein profiles in healthy and diseased ocular surface and to highlight biomarker usefulness in the early diagnosis as well as at follow-up. This analysis encompasses a deep examination of the protein profile expression under physiological and pathological conditions. Tear protein profile analysis will allow in the near future discriminating between different grades of inflammation, from acute trauma toward immune-, endocrine-, and nervous-related disorders of the ocular surface.

CONCLUDING REMARKS

The review provides an overview of old and recent findings about inflammatory mediators identified at the ocular surface, under physiological and pathological conditions. To date, the analysis of tear fluid represents a new additional approach for diagnosis and management of ocular surface diseases. Understanding the pathophysiological mechanism could also offer significant advantages to develop strategies addressed to better clarify some complex ocular surface disorders. To sum up, the possibility to provide selective biomarkers as a future target of specific diseases should be considered for supporting diagnosis and management of ocular surface diseases.

Exogenous Tissue Inhibitor of Metalloproteinase-2 Affects Matrix Metalloproteinase-2 Expression in Conjunctival Filtering Blebs and Bleb Scarring in Rats

Objective

To examine the effect of tissue inhibitor of metalloproteinase-2 (TIMP-2) on conjunctival filtering bleb scarring.

Methods

A model of conjunctival filtering bleb was established whereby rats were injected with saline, blank adenoviral vector, or adenoviral vector carrying TIMP-2 into the bleb. Filtration bleb formation and matrix metalloproteinase-2 (MMP-2) expression were examined.

Results

All operated eyes formed obvious elevated blebs on day 1. In the normal saline group, empty plasmid group, and gene transfection group maintenance time of filtrating blebs was 5–14, 5–14, and 6–16 days, and average survival time was 8.24, 8.16, and 9.44 days, respectively. MMP-2 expression increased slightly in the gene transfection group at 3 and 5 days after surgery, reached a peak after 14 days, and then gradually decreased. MMP-2 expression was weakly positive in the normal conjunctival epithelium, but was hardly detected in the lamina propria. Seven days after surgery, the epithelium and lamina propria of the conjunctival filtering bleb exhibited strong positive expression in the empty plasmid group but only weak expression in the adenovirus group.

Conclusion

Exogenous TIMP-2 interfered with local MMP-2 expression, delaying peak expression of MMP-2 and slowing the scarring of filtering blebs during wound healing of subconjunctival tissue.

Correlation between Tissue Characterization and Dynamic Expression of Matrix Metalloproteinase-2 and Its Tissue Inhibitor in Conjunctival Filtering Bleb of Rats

Purpose

Using rat conjunctival bleb model, we correlated changes morphology and histology in the bleb with changes in MMP-2 and TIMP-2 levels.

Methods

Filtering surgeries were performed on rats. Dynamic changes in morphology and histopathology were observed using HE staining. Expression of MMP-2 and TIMP-2 was determined by immunofluorescence microscopy and western blotting.

Results

Well-elevated filtering blebs formed and persisted for an average of 12 days. Histological examination showed that inflammatory was dominant in postoperative days 1–3, and proliferating manifestation became the main sign 5 days later. Western blot showed that MMP-2 was downregulated 1 day after surgery, upregulated at 3 days, and observed with a peak at 7 days; then it persisted until 28 days. The difference was statistically significant (F = 280.18, p < 0.01).TIMP-2 was upregulated 1 day after surgery and observed with a peak at 5 days; then it persisted until 28 days. The difference was statistically significant (F = 145.34, p < 0.01).

Conclusions

During the processes of conjunctival filtering bleb and scar formation in rats, the changes in MMP-2 and TIMP-2 levels in the filtering area, together with a corresponding proliferation of fibroblasts and the accumulation of collagen fibres, resulted in scarring of filtering blebs.

The selective cysteinyl leukotriene receptor 1 (CysLT1R) antagonist montelukast regulates extracellular matrix remodeling

Scar formation after filtration surgery of glaucoma is mainly caused by excessive synthesis of new extracellular matrix (ECM) and contraction of subconjunctival tissue mediated by human Tenon fibroblasts (HTFs) and the transforming growth factor (TGF-β1). Montelukast, a potent and specific cysteinyl leukotriene receptor 1 (cysLT1R) antagonist, is a licensed drug clinically used for the treatment of bronchial asthma. In this study, we investigated the effects of montelukast on the contractility of HTFs cultured in a three-dimensional collagen gel. We found that cysLT1R was expressed in HTFs. Interestingly, the expression of cysLT1R was increased in response to TGF-β1 in a dose dependent manner, suggesting its potential role in TGF-β1 induced fibrosis. Importantly, we found that montelukast inhibited TGF-β1-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner. In addition, TGF-β1-induced expression of MMP-1 and MMP-3, generation of fibronectin and type I collagen production, focal adhesion kinase (FAK) and paxillin phosphorylation in HTFs were also ameliorated by montelukast in a dose dependent manner. These results suggested that montelukast might provide therapeutic possibilities for inhibition of scar formation after such surgery.

The Association of Nailfold Capillaroscopy with Systemic Matrix Metalloproteinase-9 Concentration in Normal-Tension Glaucoma

PURPOSE

To investigate the association of nailfold capillaroscopy, heart rate variability (HRV), and clinical characteristics of glaucoma with the plasma matrix metalloproteinase-9 (MMP-9) level in normal-tension glaucoma (NTG).

MATERIALS AND METHODS

We conducted a prospective, cross-sectional study on 25 patients with NTG. Subjects with systemic diseases were excluded. The patients underwent a complete ophthalmic examination and were referred to the Rheumatology Department, where nailfold capillaroscopy and HRV assessment were performed. The patients were assigned to the lowest and highest HRV groups according to the standard deviation value of the qualified normal-to-normal intervals of the HRV assessment. Blood samples from all the subjects were assayed for MMP-9 concentrations.

RESULTS

The systemic MMP-9 level was significantly associated with the nailfold capillaroscopy result (ρ = 0.439, p = 0.032). Of the 25 patients, seven had optic disc hemorrhage (ODH). The mean MMP-9 concentration was 4375.6 ± 2923.2 pg/ml in ODH patients and 5932.1 ± 1265.4 pg/ml in patients without ODH. However, there was no significant association of HRV parameters or disc hemorrhage with the systemic MMP-9 level.

CONCLUSIONS

The systemic MMP-9 level was associated with the nailfold capillaroscopy results in patients with NTG but had no direct association with ODH.