Epigenetic regulation of αA-crystallin in high myopia-induced dark nuclear cataract

Complications of high myopia: An update from clinical manifestations to underlying mechanisms

Background

High myopia is one of the major causes of visual impairment and has an ever-increasing prevalence, especially in East Asia. It is characterized by excessive axial elongation, leading to various blinding complications that extend beyond mere refractive errors and persist immovably after refractive surgery, presenting substantial public health challenge.

Main text

High myopia-related complications include lens pathologies, atrophic and tractional maculopathy, choroidal neovascularization, peripheral retinal degenerations and retinal detachment, and glaucoma and heightened susceptibility to intraocular pressure (IOP) elevation. Pathological lens changes characteristic of high myopia include early cataractogenesis, overgrowth of lens, weakened zonules, and postoperative capsular contraction syndrome, possibly driven by inflammatory pathogenesis, etc. Dome-shaped macula and cilioretinal arteries are two newly identified protective factors for central vision of highly myopic patients. These patients also face risks of open-angle glaucoma and IOP spike following intraocular surgery. Morphologic alternations of optic nerve in high myopia can complicate early glaucoma detection, necessitating comprehensive examinations and close follow-up. Anatomically, thinner trabecular meshwork increases this risk; conversely lamina cribrosa defects may offer a fluid outlet, potentially mitigating the pressure. Notably, anxiety has emerged as the first recognized extra-ocular complication in high myopia, with an underlying inflammatory pathogenesis that connects visual stimulus, blood and brain.

Conclusions

High myopia induces multiple ocular and potential mental health complications, underscoring the need to develop more effective strategies to improve both physical and emotional well-being of these patients, among which anti-inflammation might possibly represent a promising new target.

Trends and hot spots in research related to aqueous humor from 2014 to 2023: A bibliometric analysis

Purpose

To analyze publication trends and investigate research hotspots of aqueous humor (AH) studies.

Methods

A bibliometric study was conducted based on the Web of Science Core Collection (WOSCC). VOSviewer v. 1.6.18 was utilized to create a knowledge map visualizing the number of annual publications, the distribution of countries, international collaborations, author productivity, source journals and keywords in the field.

Results

A grand total of 4020 peer-reviewed papers concerning AH were retrieved from 2014 to 2023. The United States of America secured the top position among the most published countries and Duke University emerged as the most active institution. Stamer, WD contributed the most papers in this area. Investigative Ophthalmology & Visual Science was the most prolific journal in AH research. Retrieved publications mainly concentrated on the correlation between AH as a biomarker carrier and different ocular disorders. Six clusters were formed based on the keywords: (1) the diagnosis of endophthalmitis and AH pharmacokinetics; (2) the association of AH with pathogenesis and prognosis of glaucoma; (3) diagnosis and treatment of AH associated with uveitis; (4) the relationship between AH and refractive diseases of the eye; (5) the association of AH with mechanism and biomarkers of ocular tumorigenesis; (6) the indicators of AH associated with fundus disease.

Conclusions

This study unveiled present patterns of global collaboration, emerging frontiers, fundamental knowledge, research hotspots and current trends in AH.

Comparative study of FLACS vs conventional phacoemulsification for cataract patients with high myopia

PURPOSE

To compare the short-term changes in cornea, retina, and choroid of femtosecond laser-assisted cataract surgery (FLACS) with conventional phacoemulsification (CPS) in high myopia patients with cataract.

SETTING

Affiliated Hospital of Nantong University, Jiangsu Province, China.

DESIGN

Prospective single-center study.

METHODS

Demographics, ocular clinical features, ultrasound power, absolute phacoemulsification time, and effective phacoemulsification time were recorded for each patient. Endothelial cell density (ECD), central corneal thickness (CCT), corrected distance visual acuity (CDVA), intraocular pressure (IOP), center foveal thickness (CFT), subfoveal choroidal thickness (SFCT), and choroidal vascularity index (CVI) were evaluated preoperatively and at 1 week, 1 month, and 3 months postoperatively. Intraoperative parameters and intraoperative/postoperative complications were recorded.

RESULTS

97 eyes (46 eyes and 51 eyes in the FLACS and CPS groups, respectively) were included and analyzed. Effective phacoemulsification time was lower in the FLACS group compared with the CPS group ( P < .05). The increase in CCT was significantly lower in the FLACS group compared with the CPS group at 1 week and 1 month ( P < .05). CDVA and IOP were similar in both groups at the final visit ( P > .05). The ECD decreased was lower among CPS patients compared with FLACS patients. CFT, SFCT, and CVI increase in both groups but were increased more in the CPS group with high myopia patients. No serious complications occurred in either group.

CONCLUSIONS

FLACS is a more safety and effective in cataract patients with high myopia. It has advantages in effectively reducing EPT and promoting faster recovery of the cornea, macular, and choroidal thickness.

Comparison of macular changes and visual outcomes between femtosecond laser-assisted cataract surgery and conventional phacoemulsification surgery for high myopic cataract patients

BACKGROUND

To evaluate differences in log MAR best-corrected visual acuity (BCVA) improvement and postoperative central foveal thickness (CFT) and choroidal thickness (CT) changes between conventional phacoemulsification surgery (CPS) and femtosecond laser-assisted cataract surgery (FLACS) for high-myopia cataracts.

METHODS

This was a retrospective and observational study. One hundred and two eyes of 102 patients with high-myopia cataracts were examined. CPS was performed in 54 eyes, and FLACS was performed in 48 eyes. All eyes underwent logMAR BCVA, CFT and CT of three different sectors preoperatively and one week and six months postoperatively.

RESULTS

The logMAR BCVA improved significantly after surgery in both groups (both P < 0.001), but no difference was observed in BCVA improvement between the groups (P = 0.554). Moreover, no significant differences were reflected in the changes in CFT, nasal 1 mm CT or temporal 1 mm CT between the two groups, and only subfoveal choroidal thickness (SFCT) in the CPS group decreased significantly compared with that in the FLACS group at any postoperative time (P = 0.003 and 0.026). AL, preoperative logMAR BCVA, and CT of the three regions exhibited a notable correlation with postoperative BCVA (all P < 0.05) according to univariate logistic regression analysis. However, only the AL, preoperative logMAR BCVA and SFCT remained significant in the multivariate model. Postoperative logMAR BCVA revealed a positive correlation with AL and preoperative logMAR BCVA but a negative correlation with SFCT.

CONCLUSIONS

FLACS was not superior to CPS in improving BCVA but had less impact on SFCT in the treatment of high-myopia cataracts. Eyes with a longer AL, worse preoperative logMAR BCVA and thinner SFCT had a high risk of worse postoperative BCVA.

Risk of major myopia-associated non-communicable ocular health disorders in Ghana

OBJECTIVE

To assess the differential association of myopia with major non-communicable ocular diseases in an African clinical cohort.

METHODS

A five-year hospital-based retrospective study of myopia cases. Patients' folders, Optical Coherence Tomography scans, and fundus photographs were reviewed for the abstraction of relevant data. Only records that employed recognized standards and classification systems for diagnosing and staging the various ocular conditions were included. Demographic characteristics, non-cycloplegic objective refractive findings, and non-communicable eye diseases were retrieved from the records. Myopia-associated risk factors were then determined using logistic regression and correlation.

RESULTS

Some 16018 patients (32027 eyes) met the inclusion criteria for at least one eye comprising 50.8% males (n = 8137) and 49.2% females (n = 7881). The mean age of the patients was 43.14 ± 17.88 years (range: 2-98 years). The mean spherical equivalent± Standard deviation for myopia was -2.30±3.23 DS (range: -0.50 to -25DS). Binary logistic regression analysis showed that myopic eyes had a higher odd of AC (OR, 0.53; 95% CI, 0.50-0.57), POAG (OR, 6.0; 95% CI, 5.26-6.82), DR (OR, 10.70; 95% CI, 3.91-29.27) and cataracts (OR, 20; 95% CI, 15.32-26.20) but not dry eye (OR, 0.74, 95% CI, 0.68-0.81), macular degeneration and pterygium (OR, 0.36; 95% CI, 0.32-0.40).

CONCLUSION

Africans with myopia are more at risk of developing allergic conjunctivitis, cataracts, POAG, and DR but not for dry eye, macular degeneration, and pterygium.

Challenges of refractive cataract surgery in the era of myopia epidemic: a mini-review

Myopia is the leading cause of visual impairment in the world. With ever-increasing prevalence in these years, it creates an alarming global epidemic. In addition to the difficulty in seeing distant objects, myopia also increases the risk of cataract and advances its onset, greatly affecting the productivity of myopes of working age. Cataract management in myopic eyes, especially highly myopic eyes is originally more complicated than that in normal eyes, whereas the growing population of cataract with myopia, increasing popularity of corneal and lens based refractive surgery, and rising demand for spectacle independence after cataract surgery all further pose unprecedented challenges to ophthalmologists. Previous history of corneal refractive surgery and existence of implantable collamer lens will both affect the accuracy of biometry including measurement of corneal curvature and axial length before cataract surgery, which may result in larger intraocular lens (IOL) power prediction errors and a compromise in the surgical outcome especially in a refractive cataract surgery. A prudent choice of formula for cataract patients with different characteristics is essential in improving this condition. Besides, the characteristics of myopic eyes might affect the long-term stability of IOL, which is important for the maintenance of visual outcomes especially after the implantation of premium IOLs, thus a proper selection of IOL accordingly is crucial. In this mini-review, we provide an overview of the impact of myopia epidemic on treatment for cataract and to discuss new challenges that surgeons may encounter in the foreseeable future when planning refractive cataract surgery for myopic patients.

Long-Term Outcomes of Posterior Capsular Opacification in Highly Myopic Eyes and Its Influencing Factors

INTRODUCTION

The purpose of this study was to evaluate the long-term outcomes of posterior capsular opacification (PCO) in highly myopic eyes and its influencing factors.

METHODS

Patients undergoing phacoemulsification with intraocular lens implantation and followed up for 1-5 years were included in this prospective cohort study. The severity of PCO was evaluated using EPCO2000 software system, with the area of central 3.0 mm (PCO-3 mm) and within the capsulorhexis (PCO-C) both being analyzed. Percentage of eyes after Nd:YAG capsulotomy, as well as clinically significant PCO (defined as eyes with visual-impairing PCO or after capsulotomy), were also included as outcome variables.

RESULTS

A total of 673 highly myopic eyes [axial length (AL) ≥ 26 mm] and 224 control eyes (AL < 26 mm) were analyzed. The mean follow-up time was 34.0 ± 9.0 months. PCO was more severe in highly myopic eyes compared with controls with regard to higher EPCO scores (P < 0.001 for both PCO-3 mm and PCO-C), higher capsulotomy rate (P = 0.001), higher clinically significant PCO rate (P < 0.001) and shorter PCO-free survival time (P < 0.001). Extreme myopia (AL ≥ 28 mm) would further aggravate PCO in terms of higher EPCO scores (PCO-3 mm: P = 0.017; PCO-C: P = 0.013) and higher clinically significant PCO rate (P = 0.024) compared with other myopic eyes. In highly myopic eyes, AL [odds ratio (OR) 1.124, P = 0.004] and follow-up duration (OR 1.082, P < 0.001) were independent risk factors for clinically significant PCO after cataract surgery.

CONCLUSION

Highly myopic eyes had more severe PCO in the long term. Longer AL and follow-up duration were associated with higher risk of PCO.

CLINICAL TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT03062085).

Association of Behavioral and Clinical Risk Factors With Cataract: A Two-Sample Mendelian Randomization Study

Purpose

To investigate the association of genetically determined primary open-angle glaucoma (POAG), myopic refractive error (RE), type 2 diabetes (T2D), blood pressure (BP), body mass index (BMI), cigarette smoking, and alcohol consumption with the risk of age-related cataract.

Methods

To assess potential causal effects of clinical or behavioral factors on cataract risk, we conducted two-sample Mendelian randomization analyses. Genetic instruments, based on common genetic variants associated with risk factors at genome-wide significance (P < 5 × 10-8), were derived from published genome-wide association studies (GWAS). For age-related cataract, we used GWAS summary statistics from our previous GWAS conducted in the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort (28,092 cataract cases and 50,487 controls; all non-Hispanic whites) or in the UK Biobank (31,852 cataract cases and 428,084 controls; all European-descent individuals). We used the inverse-variance weighted (IVW) method as our primary source of Mendelian randomization estimates and conducted common sensitivity analyses.

Results

We found that genetically determined POAG and mean spherical equivalent RE were significantly associated with cataract risk (IVW model: odds ratio [OR] = 1.04; 95% confidence interval [CI], 1.01-1.08; P = 0.018; per diopter more hyperopic: OR = 0.92; 95% CI, 0.89-0.93; P = 6.51 × 10-13, respectively). In contrast, genetically determined T2D, BP, BMI, cigarette smoking, or alcohol consumption were not associated with cataract risk (P > 0.05).

Conclusions

Our results provide evidence that genetic risks for POAG and myopia may be causal risk factors for age-related cataract. These results are consistent with previous observational studies reporting associations of myopia with cataract risk. This information may support population cataract risk stratification and screening strategies.

Polymorphisms in TRIB2 and CAPRIN2 Genes Contribute to the Susceptibility to High Myopia-Induced Cataract in Han Chinese Population

BACKGROUND Myopia has been shown to be associated with many pathological complications including cataracts, and previous evidence supported that high myopia facilitates the formation of cataracts. However, no studies have identified a link between the genetic susceptibility of high myopia-induced cataracts (HMC) and the underlying genetic mechanisms. Our study aimed to determine how the TRIB2 and CAPRIN2 genes correlate to the risk of HMC. MATERIAL AND METHODS In total, we successfully recruited 3162 participants, including 1026 participants with high myopia and cataracts and 2136 controls with high myopia only. For genotyping, 22 tag single nucleotide polymorphisms (SNPs) in TRIB2 and CAPRIN2 genes were chosen. Single marker association analysis and functional effects of significant SNPs were carried out. RESULTS Strong correlation signals were captured for SNP rs890069 (χ²=22.13, P=2.55×10-6) in TRIB2 and SNP rs17739338 (χ²=16.07, P=6.10×10-5) in CAPRIN2. In patients with high myopia, the C allele at SNP rs890069 was strongly linked to cataract risk (OR [95% CI]=1.36 [1.20-1.55]). In patients with high myopia, the T allele at SNP rs17739338 was significantly related to a lower risk of cataract (OR [95% CI]=0.54 [0.40-0.74]). In different types of human tissues, SNPs rs890069 and rs17739338 were found to be significantly correlated to the levels of TRIB2 and CAPRIN2 gene expression. CONCLUSIONS Our study indicated that both TRIB2 and CAPRIN2 genes conferred the susceptibility to cataract in patients with high myopia and Chinese Han ancestry. Future research remains necessary for fully understanding the pathogenic mechanisms and genetic characteristics of cataract.

Dynamic changes in whole genome DNA methylation, chromatin and gene expression during mouse lens differentiation

BACKGROUND

Cellular differentiation is marked by temporally and spatially coordinated gene expression regulated at multiple levels. DNA methylation represents a universal mechanism to control chromatin organization and its accessibility. Cytosine methylation of CpG dinucleotides regulates binding of methylation-sensitive DNA-binding transcription factors within regulatory regions of transcription, including promoters and distal enhancers. Ocular lens differentiation represents an advantageous model system to examine these processes as lens comprises only two cell types, the proliferating lens epithelium and postmitotic lens fiber cells all originating from the epithelium.

RESULTS

Using whole genome bisulfite sequencing (WGBS) and microdissected lenses, we investigated dynamics of DNA methylation and chromatin changes during mouse lens fiber and epithelium differentiation between embryos (E14.5) and newborns (P0.5). Histone H3.3 variant chromatin landscapes were also generated for both P0.5 lens epithelium and fibers by chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq). Tissue-specific features of DNA methylation patterns are demonstrated via comparative studies with embryonic stem (ES) cells and neural progenitor cells (NPCs) at Nanog, Pou5f1, Sox2, Pax6 and Six3 loci. Comparisons with ATAC-seq and RNA-seq data demonstrate that reduced methylation is associated with increased expression of fiber cell abundant genes, including crystallins, intermediate filament (Bfsp1 and Bfsp2) and gap junction proteins (Gja3 and Gja8), marked by high levels of histone H3.3 within their transcribed regions. Interestingly, Pax6-binding sites exhibited predominantly DNA hypomethylation in lens chromatin. In vitro binding of Pax6 proteins showed Pax6's ability to interact with sites containing one or two methylated CpG dinucleotides.

CONCLUSIONS

Our study has generated the first data on methylation changes between two different stages of mammalian lens development and linked these data with chromatin accessibility maps, presence of histone H3.3 and gene expression. Reduced DNA methylation correlates with expression of important genes involved in lens morphogenesis and lens fiber cell differentiation.

Next-Generation Sequencing Screening of 43 Families with Non-Syndromic Early-Onset High Myopia: A Clinical and Genetic Study

Early-onset high myopia (EoHM) is a disease that causes a spherical refraction error of ≥-6 diopters before 10 years of age, with potential multiple ocular complications. In this article, we report a clinical and genetic study of 43 families with EoHM recruited in our center. A complete ophthalmological evaluation was performed, and a sample of peripheral blood was obtained from proband and family members. DNA was analyzed using a customized next-generation sequencing panel that included 419 genes related to ophthalmological disorders with a suspected genetic cause, and genes related to EoHM pathogenesis. We detected pathogenic and likely pathogenic variants in 23.9% of the families and detected variants of unknown significance in 76.1%. Of these, 5.7% were found in genes related to non-syndromic EoHM, 48.6% in genes associated with inherited retinal dystrophies that can include a syndromic phenotype, and 45.7% in genes that are not directly related to EoHM or retinal dystrophy. We found no candidate genes in 23% of the patients, which suggests that further studies are needed. We propose a systematic genetic analysis for patients with EoHM because it helps with follow-up, prognosis and genetic counseling.

Clinical Characteristics and Early Visual Outcomes of Highly Myopic Cataract Eyes: The Shanghai High Myopia Study

Purpose: To report ocular characteristics and early visual outcomes of highly myopic cataract eyes, and to analyze the risk factors of low vision. Methods: A total of 2,027 eyes of 1,400 cataract patients with axial length (AL) ≥ 26 mm undergoing cataract surgery in Eye & ENT Hospital of Fudan University, who were registered in the Shanghai High Myopia Study, were analyzed. Routine pre-operative ophthalmic examinations were performed and macular scan of optical coherence tomography (OCT) were obtained. Macular complications, central foveal thickness (CFT) and subfoveal choroidal thickness (SFCT) were evaluated from OCT images. Ocular and surgical history and perioperative complications were also recorded. Uncorrected and best-corrected visual acuity (UCVA/BCVA) 1 month post-operatively and its influencing factors were evaluated. Results: The average AL of all involved eyes was 29.52 ± 2.26 mm, and 39.7% of which were with an AL > 30 mm and 26.4% of which were with a corneal astigmatism more than 1.5 D. Nuclear cataract accounted for the largest proportion (70.6%). The rate of overall macular complications was 27.6%. Postoperative UCVA and BCVA were 0.70 ± 0.46 and 0.25 ± 0.32 logMAR, respectively. BCVA improved significantly after surgery (vs. P < 0.001) and affected by the elongation of AL (P < 0.001) and thinning of CFT and SFCT (both P < 0.001). The risk factors of post-operative low vision (BCVA < 20/66) were macular atrophy, lamellar macular hole, high corneal astigmatism, long AL, thin SFCT and junior surgeons, odds ratios ranging from 1.54 to 54.87 (all P < 0.05). Conclusion: Cataract surgery could improve the VA of highly myopic eyes. Eye with macular complications, higher corneal astigmatism, longer AL, thinner SFCT, and who was treated by a junior surgeon, may have a high risk of low vision after surgery.

Efficacy and complications of cataract surgery in high myopia

To evaluate the efficacy and complications of cataract surgery in high myopia, a comprehensive search query was conducted from January 2000 to August 2020. A total of 19 586 highly myopic eyes from 28 studies were included. Modern cataract surgery turns out efficacious in highly myopic eyes with significant improvement of visual acuity. However, phacoemulsification-related complications such as posterior capsular rupture (3.91%, 95% CI, 1.98%-6.37%), retinal detachment (1.74%, 95% CI, 1.36%-2.15%), progressed myopic traction maculopathy (5.07%, 95% CI, 1.80%-9.37%), capsular contraction syndrome (2.1%), intraocular lens dislocation (0.58%), and transient intraocular pressure elevation (28.15%, 95% CI, 20.29%-36.70%) occurred more frequently in the highly myopic population. Separate analyses were also conducted based on follow-up period. In conclusion, modern cataract surgery was effective for highly myopic cataract patients, whereas careful precautions and sufficient follow-ups were of great value because of higher incidences of intraoperative and postoperative complications.

Racemization in cataractous lens from diabetic and aging individuals: analysis of Asp 58 residue in αA-crystallin

Cataract is the leading cause of visual impairment globally. Racemization of lens proteins may contribute to cataract formation in aging individuals. As a special type of age-related cataract (ARC), diabetic cataract (DC) is characterized by the early onset of cortical opacification and finally developed into a mixed type of cortical and nuclear opacification. We compared racemization of Asp 58 residue, a hotspot position in αA-crystallin, from the cortex and nucleus of diabetic and age-matched senile cataractous lenses, by identifying L-Asp/L-isoAsp/D-Asp/D-isoAsp by mass spectrometry. Compared to nondiabetic cataractous lenses, DC lenses showed a significantly increased cortex/nucleus ratio of D-Asp 58, which originated primarily from an increased percentage of D-Asp 58 in the lens cortex of DC. Moreover, patients diagnosed with diabetes for over 10 years showed a lower cortex/nucleus ratio of D-isoAsp 58 in the lens compared with those who had a shorter duration of diabetes, which originated mainly from an increased percentage of D-isoAsp 58 in the lens nucleus of DC with increasing time of hyperglycemia. Further analysis confirmed decreased protein solubility in diabetic cataractous lenses. The different racemization pattern in DC may be distinguished from ARC and influence its phenotype over the protracted duration of diabetes.

Aberrant TGF-β1 signaling activation by MAF underlies pathological lens growth in high myopia

High myopia is a leading cause of blindness worldwide. Myopia progression may lead to pathological changes of lens and affect the outcome of lens surgery, but the underlying mechanism remains unclear. Here, we find an increased lens size in highly myopic eyes associated with up-regulation of β/γ-crystallin expressions. Similar findings are replicated in two independent mouse models of high myopia. Mechanistic studies show that the transcription factor MAF plays an essential role in up-regulating β/γ-crystallins in high myopia, by direct activation of the crystallin gene promoters and by activation of TGF-β1-Smad signaling. Our results establish lens morphological and molecular changes as a characteristic feature of high myopia, and point to the dysregulation of the MAF-TGF-β1-crystallin axis as an underlying mechanism, providing an insight for therapeutic interventions.

High myopia is associated with lens changes, but the underlying mechanisms are unclear. Here, the authors show increased equatorial diameter of the lens in subjects affected by high myopia, and find that these changes are associated with an increase in crystallin expression driven by the transcription factor MAF and TGF-β1 signaling.

Clinical efficacy of phacoemulsification combined intraocular lens implantation for treatment of high myopia with cataract: A protocol of systematic review

BACKGROUND

The purpose of this study is to assess the clinical efficacy of phacoemulsification combined intraocular lens implantation (PILI) for the treatment of high myopia with cataract (HMC).

METHODS

In this study, the electronic databases (PUBMED, EMBASE, Cochrane Library, Scopus, AMED, CINAHL, PsychINFO, CBM, and China National Knowledge Infrastructure) will be searched from inception to present. All randomized controlled trials on assessing the PILI for patients with HMC will be included. Two authors will carry out study selection, information extraction, and study quality assessment, respectively. We will invite another author to solve any disagreement through discussion. RevMan 5.3 software will be performed for data synthesis and analysis.

RESULTS

This study will present a detailed synthesis and/or descriptive analysis of the most recent evidence to evaluate the efficacy of PILI for HMC.

CONCLUSION

The results of this study may provide possible guidance to determine whether or not PILI is effective on HMC.

Measurement of crystalline lens tilt in high myopic eyes before cataract surgery using swept-source optical coherence tomography

Background

To measure the crystalline lens tilt in eyes with various degrees of myopia before cataract surgery using swept-source optical coherence tomography (SS-OCT).

Methods

We used SS-OCT (IOLMaster 700) to scan 131 emmetropic eyes (axial length < 24.5 mm), 25 mild/moderate myopic eyes (axial length 24.5-26 mm), and 123 high myopic eyes (52, 29, and 42 eyes with axial lengths of 26-28, 28-30, and > 30 mm, respectively) as part of the routine preoperative examination before cataract surgery. SS-OCT involved B-scans along six meridians. The data were analyzed to assess the magnitude and orientation of the lens tilt and their correlation with other optical biometric parameters.

Result

The mean tilt was 3.36 ± 0.98° in emmetropic eyes, 3.07 ± 1.04° in mild/medium myopic eyes, and 2.35 ± 1.01° in high myopic eyes. Tilt correlated significantly and inversely with axial length (Pearson's r = - 0.427, P < 0.001). The crystalline lens tilt predominantly faced the upper outer quadrant relative to the visual axis, symmetrically in both eyes, with mean angles of 24.32° and 147.36° in the right and left eyes, respectively. The variability in the lens tilt direction increased with increasing axial length (χ² test, P < 0.001).

Conclusion

The magnitude of crystalline lens tilt decreased with increasing axial length. The direction of tilt was predominantly towards the upper outer quadrant in both eyes. The variability in the tilt orientation increased with increasing axial length.

Trial registration

NIH (clinicaltrial.gov), NCT03062085. Registered 23 February 2017.

The expression of cytokines in aqueous humor of high myopic patients with cataracts

Purpose

To analyze the expression of 440 human cytokines in aqueous humor of high myopic patients with cataracts.

Methods

Eighty-five patients with cataracts were recruited in this study. In the screening stage, the RayBio G-Series Human Cytokine Antibody Array 440 was used to assay the aqueous humor samples collected from nine high myopic patients with cataracts and eight non-myopic patients with cataracts right before the surgery. The array was further used for verification of the screened cytokines, with aqueous humor samples obtained from 34 eyes of high myopic patients with cataracts and 34 eyes of non-myopic patients with cataracts.

Results

Compared with the non-myopic patients with cataracts, the expression levels of decorin, receptor activator of NF-kB (RANK), angiopoietin-1 (ANG-1), C-X-C motif ligand 16 (CXCL16), β-inducible gene-h3 (bIG-H3), insulin-like growth factor-binding protein 2 (IGFBP-2), and interleukin-17B (IL-17B) were statistically significantly higher in high myopic patients with cataracts (all p<0.000114). The matrix metalloproteinase-2 (MMP-2) level also increased in the aqueous humor of high myopic patients with cataracts (p = 0.0034). The concentrations of ANG-1 and MMP-2 were also increased in the aqueous humor of the confirmatory stage (all p<0.05).

Conclusions

In this study, numerous cytokines in aqueous humor were detected in high myopic patients with cataracts and non-myopic patients with cataracts, and it was confirmed that the MMP-2 level in the aqueous humor of patients with high myopia was statistically significantly increased. Further verification also revealed the elevation of ANG-1 in the aqueous humor of high myopic patients with cataracts, which suggests that ANG-1 may be related to the pathogenesis of high myopia.

The Necessity for Second-eye Cataract Surgery in Bilateral Highly Myopic Patients with Good Visual Acuity in the Unoperated Fellow Eye

PURPOSE

To evaluate the necessity for second-eye cataract surgery in bilateral highly myopic patients with good visual acuity in the unoperated fellow eye.

MATERIALS AND METHODS

Seventy-five bilateral highly myopic patients who underwent uneventful sequential cataract surgery (the eye with worse visual acuity operated first) were included in this prospective study. The preoperative BCVA of the eye with better visual acuity in these patients was ≤ 0.3 (logMAR, or Snellen ≥ 20/40). Binocular single vision examinations were performed 1 month after the first-eye and second-eye surgery, respectively. The VF-14 questionnaire was completed before first-eye surgery, 1 month after the first-eye and 1 month after the second-eye surgery, respectively.

RESULTS

The first eye's postoperative SE was -3.07 ± 1.10D and the second eye's preoperative SE was -12.91 ± 5.15D. Binocular single vision functional parameters improved significantly after the second-eye cataract surgery compared with that after the first-eye surgery (all P < .001). The binocular single vision function was negatively correlated with the SE difference between the two eyes after the first-eye surgery. No difference was found between the scores of VF-14 questionnaire preoperatively and after the first-eye surgery. VF-14 score only improved significantly after the second-eye surgery compared with that after the first-eye surgery (P < .001).

CONCLUSION

In bilateral highly myopic cataract patients, binocular single vision function could improve significantly after the second-eye cataract surgery compared with after the first-eye surgery. Bilateral highly myopic patients may undergo second-eye cataract surgery earlier, even if cataract in that eye is not severe enough to affect the visual acuity.

Histone acetyltransferase and Polo-like kinase 3 inhibitors prevent rat galactose-induced cataract

Diabetic cataracts can occur at an early age, causing visual impairment or blindness. The detailed molecular mechanisms of diabetic cataract formation remain incompletely understood, and there is no well-documented prophylactic agent. Galactose-fed rats and ex vivo treatment of lenses with galactose are used as models of diabetic cataract. To assess the role of histone acetyltransferases, we conducted cataract prevention screening with known histone acetyltransferase (HAT) inhibitors. Ex vivo treatment with a HAT inhibitor strongly inhibited the formation of lens turbidity in high-galactose conditions, while addition of a histone deacetylase (HDAC) inhibitor aggravated turbidity. We conducted a microarray to identify genes differentially regulated by HATs and HDACs, leading to discovery of a novel cataract causative factor, Plk3. Plk3 mRNA levels correlated with the degree of turbidity, and Plk3 inhibition alleviated galactose-induced cataract formation. These findings indicate that epigenetically controlled Plk3 influences cataract formation. Our results demonstrate a novel approach for prevention of diabetic cataract using HAT and Plk3 inhibitors.

Profiling and Bioinformatic Analysis of Differentially Expressed Cytokines in Aqueous Humor of High Myopic Eyes - Clues for Anti-VEGF Injections

Purpose: To investigate the aqueous humor growth factor profile in high myopic eyes and analyze the interaction of differentially expressed cytokines.Methods: A case-control study including aqueous humor samples from 36 high myopic patients and 32 controls was conducted. Quantibody® Human Growth Factor Array was used to screen the presence of 40 growth factors in aqueous humor. Expressions of differential growth factors were validated by Bio-Plex Pro^TM multiplex bead-based immunoassay. Protein-protein interaction (PPI) and gene ontology (GO) analyses were performed.Results: Growth differentiation factor 15 (GDF-15), hepatocyte growth factor (HGF), and platelet-derived growth factor (PDGF)-AA were found to be significantly higher and vascular endothelial growth factor (VEGF) was detected to be lower in high myopic eyes (all P = .03). Multi-plex bead-based assay further validated the differential expressions of four growth factors and all of them were significantly correlated with axial length (P < .001). Twenty-six proteins were mapped into PPI network and positive regulation of cell migration, cellular component movement, and cell motility were the most enriched biological processes based on GO analysis.Conclusions: Differential expressed cytokines that indicates a distinctive intraocular microenvironment in high myopic eyes might provide clues for pathological changes within high myopic eyes after anti-VEGF injections.

Fixation Characteristics in Highly Myopic Eyes: the Shanghai High Myopia Study

We enrolled 500 highly myopic eyes and 50 controls in this hospital-based prospective cohort study. The fixation ellipse angle and area in terms of the bivariate contour ellipse area (BCEA) were measured with Macular Integrity Assessment microperimetry. Optic disc tilt and rotation were evaluated with retinal images. The associations between fixation and optic disc changes were assessed. Both 63% and 95% BCEA correlated positively with axial length (AL) (both r = 0.230, P = 0.001) in highly myopic group, and were significantly higher than the control group (both P < 0.001). The direction of fixation ellipse presented clockwise rotation in the right eyes and anti-clockwise rotation in the left eyes with the increase of AL in highly myopic group (AL ≥30 vs <30 mm: OD 76.12 ± 51.17°: vs 90.60° ± 51.28°, P = 0.029; OS 94.73 ± 57.45° vs 87.82 ± 55.15°, P = 0.371). The angle between the long axis of the fixation ellipse and the long axis of the optic disc (Angle_F−D) distributed in various directions: 0–30° (34.6% almost parallel) ≈60–90° (34.4% almost vertical) >30–60° (31% oblique). Angle_F−D increased slightly with the AL (r = 0.105, P = 0.024). In highly myopic eyes, fixation stability decreased with the AL, and superior rotation of the fixation ellipse increased with AL. The long axis of fixation ellipse and the long axis of optic disc became less parallel to each other with increasing AL. Our data may provide clues for improvement of fixation evaluation designs of biometric instruments.

IMI - Myopia Genetics Report

The knowledge on the genetic background of refractive error and myopia has expanded dramatically in the past few years. This white paper aims to provide a concise summary of current genetic findings and defines the direction where development is needed. We performed an extensive literature search and conducted informal discussions with key stakeholders. Specific topics reviewed included common refractive error, any and high myopia, and myopia related to syndromes. To date, almost 200 genetic loci have been identified for refractive error and myopia, and risk variants mostly carry low risk but are highly prevalent in the general population. Several genes for secondary syndromic myopia overlap with those for common myopia. Polygenic risk scores show overrepresentation of high myopia in the higher deciles of risk. Annotated genes have a wide variety of functions, and all retinal layers appear to be sites of expression. The current genetic findings offer a world of new molecules involved in myopiagenesis. As the missing heritability is still large, further genetic advances are needed. This Committee recommends expanding large-scale, in-depth genetic studies using complementary big data analytics, consideration of gene-environment effects by thorough measurement of environmental exposures, and focus on subgroups with extreme phenotypes and high familial occurrence. Functional characterization of associated variants is simultaneously needed to bridge the knowledge gap between sequence variance and consequence for eye growth.

DNA Methylation and Uveal Melanoma

Objective:

The objective of the study was to summarize the role of DNA methylation in the development and metastasis of uveal melanoma (UM).

Data Sources:

The relevant studies in MEDLINE were searched.

Study Selection:

In this review, we performed a comprehensive literature search in MEDLINE using “uveal melanoma” AND (“DNA methylation” OR “epigenetics”) for original research/review articles published before February 2018 on the relationship between DNA methylation and UM. References of the retrieved studies were also examined to search for potentially relevant papers.

Results:

Previous studies on the relationship between DNA methylation and UM covered many genes including tumor suppressor genes (TSGs), cyclin-dependent kinase genes, and other genes. Among them, the TSG genes such as RASSF1A and p16INK4a, which encodes a cyclin-dependent kinase inhibitor, are relatively well-studied genes. Specifically, a high percentage of promoter methylation of RASSF1A was observed in UM cell lines and/or patients with UM. Promoter methylation of RASSF1A was also associated with the development of metastasis. Similarly, a high percentage of promoter hypermethylation of p16INK4a was found in UM cell lines. DNA promoter methylation can control the expression of p16INK4a, which affect cell growth, migration, and invasion in UM. Many other genes might also be involved in the pathogenesis of UM such as the Ras and EF-hand domain containing (RASEF) gene, RAB31, hTERT, embryonal fyn-associated substrate, and deleted in split-hand/split-foot 1.

Conclusions:

Our review reveals the complex mechanisms underlying the tumorigenesis of UM and highlights the great needs of future studies to discover more genes/5’-C-phosphate-G-3’ sites contributing to the development/metastasis of UM and explore the mechanisms through which epigenetic changes exert their function in UM.

DNA hypermethylation-mediated downregulation of antioxidant genes contributes to the early onset of cataracts in highly myopic eyes

High myopia is recognized as a risk factor for earlier onset of nuclear cataracts. One possible explanation for this is that lenses in highly myopic eyes are exposed to higher levels of oxygen than normal eyes owing to earlier vitreous liquefaction and, hence, are subjected to oxidative insults. Here, we first compared the methylation levels of six essential antioxidant genes (GSTP1, NRF2, OGG1, TXN, TXNRD1 and TXNRD2) between highly myopic cataract (HMC) and age-related cataract (ARC) lens epithelial samples via Sequenom MassARRAY. We found that specific CpG units in the promoters of GSTP1 and TXNRD2 were hypermethylated and that the expression levels of these two genes were lower in the HMC group than in the ARC group. A luciferase reporter assay confirmed the significance of differentially methylated fragments in the activation of transcription. The importance of GSTP1 and TXNRD2 in antioxidant capacity was confirmed by overexpression or knockdown experiments on cultured lens epithelial cells (LECs). In addition, the expression of DNA methyl transferase 1 (DNMT1) was higher in the lens epithelium of HMC patients than that of ARC patients, and the expression of GSTP1 and TXNRD2 was upregulated by use of a DNMT inhibitor in cultured LECs. Finally, we mimicked the intraocular environment of highly myopic eyes by treating LECs with hydrogen peroxide (H₂O₂) and observed both alterations in the methylation status of the GSTP1 and TXNRD2 promoters and time-dependent altered expression levels. Therefore, we propose that in an environment with high oxygen, in which lenses in highly myopic eyes are immersed, there exists a vicious cycle composed of increased oxidative stress and decreased enzymatic antioxidants via the hypermethylation of antioxidant genes.

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Vitreous liquefaction generates a high-O2 environment surrounding the lens.

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In highly myopic eyes, vitreous liquefaction occurs earlier and results in severer nuclear cataract.

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Methylation levels of GSTP1 and TXNRD2 were elevated in lens epithelium of highly myopic eyes.

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Increased oxidation and decreased enzymatic antioxidant via hypermethylation form a vicious circle in highly myopic eyes.

The Proteome of Cataract Markers: Focus on Crystallins

Cataract is a major cause of blindness worldwide. It is characterized by lens opacification and is accompanied by extensive posttranslational modifications (PTMs) in various proteins. PTMs play an essential role in lens opacification. Several PTMs have been described in proteins isolated from relatively old human lenses, including phosphorylation, deamidation, racemization, truncation, acetylation, and methylation. An overwhelming majority of previous cataract proteomic studies have exclusively focused on crystallin proteins, which are the most abundant proteome components of the lens. To investigate the proteome of cataract markers, this chapter focuses on the proteomic research on the functional relevance of the major PTMs in crystallins of human cataractous lenses. Elucidating the role of these modifications in cataract formation has been a challenging task because they are among the most difficult PTMs to study analytically. The proteomic status of some amides presents similar properties in normal aged and cataractous lenses, whereas some may undergo greater PTMs in cataract. Therefore, it is of great importance to review the current proteomic research on crystallins, the major protein markers in different types of cataract, to elucidate the pathogenesis of this major human-blinding condition.

Racemization at the Asp 58 residue in αA-crystallin from the lens of high myopic cataract patients

Post-translational modifications in lens proteins are key causal factors in cataract. As the most abundant post-translational modification in the lens, racemization may be closely related to the pathogenesis of cataract. Racemization of αA-crystallin, a crucial structural and heat shock protein in the human lens, could significantly influence its structure and function. In previous studies, elevated racemization from l-Asp 58 to d-isoAsp58 in αA-crystallin has been found in age-related cataract (ARC) lenses compared to normal aged human lenses. However, the role of racemization in high myopic cataract (HMC), which is characterized by an early onset of nuclear cataract, remains unknown. In the current study, apparently different from ARC, significantly increased racemization from l-Asp 58 to d-Asp 58 in αA-crystallin was identified in HMC lenses. The average racemization rates for each Asp isoform were calculated in ARC and HMC group. In ARC patients, the conversion of l-Asp 58 to d-isoAsp 58, up to 31.89%, accounted for the main proportion in racemization, which was in accordance with the previous studies. However, in HMC lenses, the conversion of l-Asp 58 to d-Asp 58, as high as 35.44%, accounted for the largest proportion of racemization in αA-crystallin. The different trend in the conversion of αA-crystallin by racemization, especially the elevated level of d-Asp 58 in HMC lenses, might prompt early cataractogenesis and a possible explanation of distinct phenotypes of cataract in HMC.

UV-B induced fibrillization of crystallin protein mixtures

Environmental factors, mainly oxidative stress and exposure to sunlight, induce the oxidation, cross-linking, cleavage, and deamination of crystallin proteins, resulting in their aggregation and, ultimately, cataract formation. Various denaturants have been used to initiate the aggregation of crystallin proteins in vitro. All of these regimens, however, are obviously far from replicating conditions that exist in vivo that lead to cataract formation. In fact, it is our supposition that only UV-B radiation may mimic the observed in vivo cause of crystallin alteration leading to cataract formation. This means of inducing cataract formation may provide the most appropriate in vitro platform for in-depth study of the fundamental cataractous fibril properties and allow for testing of possible treatment strategies. Herein, we showed that cataractous fibrils can be formed using UV-B radiation from α:β:γ crystallin protein mixtures. Characterization of the properties of formed aggregates confirmed the development of amyloid-like fibrils, which are in cross-β-pattern and possibly in anti-parallel β-sheet arrangement. Furthermore, we were also able to confirm that the presence of the molecular chaperone, α-crystallin, was able to inhibit fibril formation, as observed for ‘naturally’ occurring fibrils. Finally, the time-dependent fibrillation profile was found to be similar to the gradual formation of age-related nuclear cataracts. This data provided evidence for the initiation of fibril formation from physiologically relevant crystallin mixtures using UV-B radiation, and that the formed fibrils had several traits similar to that expected from cataracts developing in vivo.

Identification of proteins in the aqueous humor associated with cataract development using iTRAQ methodology

Proteins in the aqueous humor (AH) are important in the induction of cataract development. The identification of cataract-associated proteins assists in identifying patients and predisposed to the condition and improve treatment efficacy. Proteomics analysis has previously been used for identifying protein markers associated with eye diseases; however, few studies have examined the proteomic alterations in cataract development due to high myopia, glaucoma and diabetes. The present study, using the isobaric tagging for relative and absolute protein quantification methodology, aimed to examine cataract-associated proteins in the AH from patients with high myopia, glaucoma or diabetes, and controls. The results revealed that 445 proteins were identified in the AH groups, compared with the control groups, and 146, 264 and 130 proteins were differentially expressed in the three groups of patients, respectively. In addition, 44 of these proteins were determined to be cataract‑associated, and the alterations of five randomly selected proteins were confirmed using enzyme-linked immunosorbent assays. The biological functions of these 44 cataract-associated proteins were analyzed using Gen Ontology/pathways annotation, in addition to protein‑protein interaction network analysis. The results aimed to expand current knowledge of the pathophysiologic characteristics of cataract development and provided a panel of candidates for biomarkers of the disease, which may assist in further diagnosis and the monitoring of cataract development.

CpG site methylation in CRYAA promoter affect transcription factor Sp1 binding in human lens epithelial cells

BACKGROUND

Age-related cataract (ARC) is the leading cause of visual impairment worldwide, and α-crystallin (CRYAA) is the predominant structural protein involved in the maintenance of lens clarity and refractive properties. We previously demonstrated that CRYAA genes undergo epigenetic repression in the lens epithelia in ARC. We further analyze the underlying mechanism in the current study.

METHODS

The transcription factor binding sites of the CpG island of CRYAA promoter were predicted by TESS website. An electrophoretic mobility shift assay (EMSA) was used to analyze the impact of the methylation of CpG sites on transcription factors. Human lens epithelial B-3 (HLE B-3) Cells were treated with demethylation agent zebularine in the concentrations of 0 (PBS as control), 10 μM, 20 μM, 50 μM, 100 μM and 200 μM, respectively. After treatment in the above concentrations for 24 h, 48 h and 72 h, respectively, CRYAA mRNA expression levels were detected by Quantitative Real-Time RT-PCR.

RESULTS

The methylation of the CpG site of the CRYAA promoter decreased the DNA-binding capacity of transcription factor Sp1. Zebularine increased CRYAA expression in HLE B-3 Cells in a dose- dependent and time- dependent pattern.

CONCLUSIONS

The evidence presented suggests that the methylation of the CpG sites of the CRYAA promotor directly affect Sp1 binding, leading to down expression of CRYAA in human lens epithelial cells. Zebularine treatment could restore CRYAA expression in a dose- dependent and time- dependent pattern.

Ultraviolet-B induces ERCC6 repression in lens epithelium cells of age-related nuclear cataract through coordinated DNA hypermethylation and histone deacetylation

Background

Ultraviolet-B (UVB) exposure attributes to the formation of age-related nuclear cataract (ARNC), which is mediated with DNA damage. DNA damage, an important factor for pathogenesis of ARNC, is induced by UVB, and is generally resolved by the nucleotide excision repair (NER) repair mechanism. Cockayne syndrome complementation group B (CSB) protein coded by ERCC6 is a vital component for NER. However, we found no association between selected ERCC6 polymorphisms and ARNC. In this study, we investigated whether UVB exposure could alter ERCC6 expression and the process could involve epigenetic changes of DNA methylation and/or histone acetylation of ERCC6 in the lens epithelial cells (LECs). We also assessed the involvement of those coordinated changes in lens tissue from ARNC patients.

Results

mRNA and protein expression of ERCC6 in lens tissue (LECs) were lower in ARNCs than those in the controls. This reduction corresponded to methylation of a CpG site at the ERCC6 promoter and histone modifications (methylation and acetylation) nearby this site. UVB-treated human lens epithelium B3 (HLE-B3) and 239T cell presented (1) increased apoptosis, suggesting reduced UV-damage repair, (2) hypermethylation of the CpG site located at position -441 (relative to transcription start site) within the binding region for transcriptional factor Sp1 in the ERCC6 promoter, (3) the enhancement of histone H3K9 deacetylation, (4) induction in DNA methyltransferases 3b (DNMT3b) and histone deacetylase1 (HDAC1) associated to the CpG site of ERCC6 by CHIP assay.

Conclusions

These findings suggest an orchestrated mechanism triggered by UVB radiation where the concurrent association of specific hypermethylation CpG site, H3K9 deacetylation of ERCC6, and repression of ERCC6 gene expression. Taken together, with the similar changes in the lens tissue from ARNC patients, our data unveiled a possible mechanism of epigenetic modification of DNA repair gene in the pathogenesis of ARNC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0229-y) contains supplementary material, which is available to authorized users.

Oxidative Stress Levels in Aqueous Humor from High Myopic Patients

Purpose

To compare oxidative stress status in the aqueous humor of highly myopic eyes and control eyes.

Methods

Aqueous humor samples were collected from 15 highly myopic eyes (high myopia group) and 23 cataractous eyes (control group) during cataract surgery. Central corneal thickness, corneal endothelial cell density, hexagonality of corneal endothelial cells, and cell area of corneal endothelial cells were measured using specular microscopy. Axial length was measured using ultrasound biometry. 8-Hydroxydeoxyguanosine (8-OHdG) and malondialdehyde levels were measured using enzyme-linked immunosorbent assay.

Results

8-OHdG level was lower in the aqueous humor of myopic patients than in that of control group (p = 0.014) and was positively correlated with central corneal thickness and negatively correlated with axial length (r = 0.511, p = 0.02; r = -0.382, p < 0.001). There was no correlation between 8-OHdG level and corneal endothelial cell density, hexagonality, or cell area. Malondialdehyde level did not show any correlation with any parameters evaluated.

Conclusions

8-OHdG might be a sensitive biomarker for evaluating oxidative stress status in the eye. Oxidative stress level was lower in the aqueous humor of highly myopic eyes compared to that in control eyes, which indicates lower metabolic activity in these eyes.

Elevated Transforming Growth Factor-β2 in the Aqueous Humor: A Possible Explanation for High Rate of Capsular Contraction Syndrome in High Myopia

Purpose. The purpose of the study was to elucidate the role of transforming growth factor-beta 2 (TGF-β2) in the development of high myopic capsular contraction syndrome. Methods. Nineteen cases of capsular contraction syndrome, including 14 with high myopia, were collected, and their clinical data were reviewed. Aqueous humor and anterior capsular membranes were obtained during capsulotomy. Hematoxylin-eosin and immunohistochemical staining with anti-TGF-β2 antibody were performed on capsular membranes. TGF-β2 levels in aqueous humor were assayed using ELISA and western blot. Results. High myopia was significantly associated with the incidence of capsular contraction syndrome (odds ratio: 14.74, P < 0.001, 95% CI: 5.29–41.05). Histopathological analysis revealed proliferation of fibroblast-like lens epithelial cells on the shrunken anterior capsule, labeled with TGF-β2 antibodies. ELISA and Western blot showed higher levels of TGF-β2 in aqueous humor of patients with capsular contraction syndrome and high myopia. Conclusions. High myopia is a risk factor for capsular contraction syndrome. Elevated TGF-β2 levels in high myopic cataract patients may play an important role in the pathogenesis of capsular contraction syndrome.

UPR Activation and the Down-Regulation of α-Crystallin in Human High Myopia-Related Cataract Lens Epithelium

Purpose

To investigate the expression of αA- and αB-crystallin and the unfolded protein response in the lens epithelium of patients with high myopia-related cataracts.

Methods and Materials

The central portion of the human anterior lens capsule together with the adhering epithelial cells, approximately 5 mm in diameter, were harvested and processed within two hours after cataract surgery from high myopia-related (spherical equivalent ≥-10.00 diopters) and age-related cataract patients or from high myopia but non-cataractous patients (tissue were collected from ocular trauma patients with high myopia and lens trauma). Anterior lens samples from fresh cadaver normal human eyes were used as normal control (collected within 6 hours from death). Real-time PCR was performed to detect the mRNA levels of α-crystallins as well as unfolded protein response (UPR)-related GRP78, spliced-XBP1, ATF4 and ATF6. Western blot analysis was used to determine the protein level of α-crystallin, GRP78, p-IRE1α, p-eIF2α and ATF6.

Results

In the lens epithelium of the high myopia-related cataract group and the age related cataract group, the mRNA and soluble protein expression of αA- and αB-crystallin were both decreased; additionally, the protein levels of ATF6, p-eIF2α and p-IRE1α and the gene expression levels of spliced XBP1, GRP78, ATF6 and ATF4 were greatly increased relative to the normal control.

Conclusion

These results suggest the significant loss of soluble α-crystallin and the activation of the UPR in the lens epithelium of patients with high myopia-related cataract, which may be associated with the cataractogenesis of high myopia-related cataract.

Proinflammatory status in the aqueous humor of high myopic cataract eyes

High myopia has long been recognized as an inflammation-related disease, and high myopic eyes are thought to have a proinflammatory internal microenvironment, which might predispose to the occurrence of certain inflammation-related complications such as fibrotic capsular contraction syndrome after cataract surgery. Therefore, the purpose of this study was to detect inflammatory cytokines expressed in the aqueous humor (AH) of high myopic cataract (HMC) patients. The cytokines were screened using a RayBio Human Cytokine Antibody Array in AH samples from 15 age-related cataract (ARC) patients and 15 HMC patients. Those detected by the screening assays were verified using a Bio-Plex Suspension Array System in AH samples from 35 ARC patients and 45 HMC patients. The cytokine antibody array showed that the expression level of interleukin-1 receptor antagonist (IL-1ra) in the AH was higher in ARC than in HMC, whereas opposite trends were found for monocyte chemoattractant protein-1 (MCP-1), regulated on activation, normal T-cell expressed and presumably secreted (RANTES), IL-8, platelet-derived growth factor-BB, and IL-6 (all P < 0.05). In the verification assay using the suspension cytokine array, only the expression levels of IL-1ra and MCP-1 were significantly different between the ARC and HMC groups (P = 0.014 and 0.038, respectively); these results were confirmed by western blot assays. Our results demonstrated that the expression of IL-1ra was significantly lower and the expression of MCP-1 was significantly higher in the AH of HMC than in ARC, suggestive of a proinflammatory status in the anterior chamber of HMC eyes.

αA-crystallin gene CpG islands hypermethylation in nuclear cataract after pars plana vitrectomy

PURPOSE

To investigate the DNA methylation status of αA-crystallin gene in cataract secondary to pars plana vitrectomy.

METHODS

Anterior capsular membranes of 40 eyes of 40 patients with cataract secondary to vitrectomy were collected. Another 20 eyes of 20 patients who received pars plana vitrectomy and phacoemulsification in the primary procedure, were recruited as control. Methylation status of the CpG islands of αA-crystallin gene was analyzed by pyrosequencing. Expression of αA-crystallin was evaluated by real-time polymerase chain reaction and western blot.

RESULTS

In the post vitrectomy group, five patients with posterior subcapsular opacity and four patients with cortical opacity were excluded from further analysis. The remaining 31 patients with nuclear cataract were assigned into two groups according to tamponade types: 19 of octafluoropropane (C3F8) and 12 of silicone oil (SiO). The average nuclear color grading was elevated both in C3F8 and SiO groups after vitrectomy. Compared to the control group, hypermethylation of the CpG islands in the αA-crystallin gene promoter was found in both post vitrectomy groups, accompanied by significantly reduced αA-crystallin expression. No statistically significant differences were found between the C3F8 and SiO groups either for DNA methylation status or αA-crystallin expression.

CONCLUSIONS

CpG islands hypermethylation of αA-crystallin gene may be involved in nuclear cataract formation after pars plana vitrectomy.

Effect of pupil size on higher-order aberrations in high-myopic pseudophakic eyes with posterior staphyloma

PURPOSE

To evaluate the effect of pupil size on higher-order aberrations (HOAs) in high-myopic pseudophakic eyes with posterior staphyloma using KR-1W aberrometer.

METHODS

Forty eyes of 40 high-myopic cataract patients with posterior staphyloma and 20 eyes of 20 age-related cataract patients with normal axial length were recruited. At 1 month after phacoemulsification and intraocular lens implantation, ocular and internal HOAs as well as the visual quality data in the two groups were evaluated with KR-1W analyzer before and after mydriasis.

RESULTS

Compared with normal axial length eyes, high-myopic pseudophakic eyes with posterior staphyloma had significantly lower values of internal coma both under 4-mm and 6-mm pupil sizes (P<0.001 and 0.020), as well as internal total HOAs (P<0.001) and third-order aberrations at 6-mm pupil size (P=0.018). Statistically significant differences were also found in the variation from 4- to 6-mm pupil sizes for internal coma (P=0.001), internal third-order aberrations (P=0.009), internal total HOAs (P=0.007), and ocular coma aberrations (P=0.006) between two groups. After mydriasis, Strehl ratio increased significantly in high-myopic eyes, whereas decreased slightly in normal axial length eyes (P=0.032 when compared with the variation between the two groups). Statistically significant differences were also found for the variation of modulation transfer functions (MTFs) at frequencies of 15, 30, 45, and 60 cycles/degree between the two groups (P=0.002, 0.002, 0.004, and 0.010, respectively).

CONCLUSIONS

High-myopic pseudophakic eyes with posterior staphyloma had significantly lower internal coma and less coma variations during mydriasis.