C-reactive protein and complement components in patients with pathological myopia

Complement decay-accelerating factor inhibits inflammation-induced myopia development

Myopia is regarded as a worldwide epidemic ocular disease, has been proved related to inflammation. CD55, also known as decay-accelerating factor (DAF) can modulate the activation of complement through inhibiting the formation of complement 3 convertase and its dysregulation is involved in various inflammatory diseases. To investigate the association between CD55 and myopia, and to test whether CD55 can inhibit myopia development by suppressing inflammation in the eye, we use three different animal models including monocular form-deprivation myopia, myopia induced by TNF-α administration and allergic conjunctivitis animal model to reveal the CD55 in myopia development. The tears of thirty-eight participants with different spherical equivalents were collected and CD55 in the tears were also analyzed. Complement 3 and complement 5 levels increased while CD55 levels decreased in allergic conjunctivitis and myopic eyes. After anti-inflammatory drugs administration, CD55 expression was increased in monocular form-deprivation myopia model. We also found inflammatory cytokines TGF-β, IL-6, TNF-α, and IL-1β may enhance complement 3 and complement 5 activation while CD55 level was suppressed contrary. Moreover, lower CD55 levels were found in the tears of patients with myopia with decreased diopter values. Finally, CD55-Fc administration on the eyelids can inhibit the elongation of axial length and change of refractive error. CD55-Fc application also suppress myopia development subsequent to complement 3 and complement 5 reduction and can lower myopia-specific (MMP-2 and TGF-β) cytokine expression in TNF-α induced myopia animal model. This suggests that CD55 can inhibit myopia development by suppression of complement activation and eventual down-regulation of inflammation.

Developing and validating a clinlabomics-based machine-learning model for early detection of retinal detachment in patients with high myopia

BACKGROUND

Retinal detachment (RD) is a vision-threatening disorder of significant severity. Individuals with high myopia (HM) face a 2 to 6 times higher risk of developing RD compared to non-myopes. The timely identification of high myopia-related retinal detachment (HMRD) is crucial for effective treatment and prevention of additional vision impairment. Consequently, our objective was to streamline and validate a machine-learning model based on clinical laboratory omics (clinlabomics) for the early detection of RD in HM patients.

METHODS

We extracted clinlabomics data from the electronic health records for 24,440 HM and 5607 HMRD between 2015 and 2022. Lasso regression analysis assessed fifty-nine variables, excluding collinear variables (variance inflation factor > 10). Four models based on random forest, gradient boosting machine (GBM), generalized linear model, and Deep Learning Model were trained for HMRD diagnosis and employed for internal validation. An external test of the models was done. Three random data sets were further processed to validate the performance of the diagnostic model. The primary outcomes were the area under the receiver operating characteristic curve (AUC) and the area under the precision-recall curve (AUCPR) to diagnose HMRD.

RESULTS

Nine variables were selected by all models. Given the AUC and AUCPR values across the different sets, the GBM model was chosen as the final diagnostic model. The GBM model had an AUC of 0.8550 (95%CI = 0.8322-0.8967) and an AUCPR of 0.5584 (95%CI = 0.5250-0.5879) in the training set. The AUC and AUCPR in the internal validation were 0.8405 (95%CI = 0.8060-0.8966) and 0.5355 (95%CI = 0.4988-0.5732). During the external test evaluation, it reached an AUC of 0.7579 (95%CI = 0.7340-0.7840) and an AUCPR of 0.5587 (95%CI = 0.5345-0.5880). A similar discriminative capacity was observed in the three random data sets. The GBM model was well-calibrated across all the sets. The GBM-RD model was implemented into a web application that provides risk prediction for HM individuals.

CONCLUSION

GBM algorithms based on nine features successfully predicted the diagnosis of RD in patients with HM, which will help ophthalmologists to establish a preliminary diagnosis and to improve diagnostic accuracy in the clinic.

The role of transforming growth factor beta in myopia development

Myopia is widely recognized as an epidemic. Studies have found a link between Transforming Growth Factor-beta (TGF-β) and myopia, but the specific molecular mechanisms are not fully understood. In this study, a monocular model in tree shrews (Tupaia belangeri) was established to verify the molecular mechanism of TGF-β in myopia. The results indicated that there were significant changes in TGF-βs during the treatment of myopia, which could enhance the refractive ability and axial length of the eye. Immunohistochemical staining, real-time fluorescent quantitative PCR, and immunoblotting results showed a significant upregulation of MMP2 and NF-κB levels, and a significant downregulation of COL-I expression in the TGF-β treated eyes, suggesting that NF-κB and MMP2 are involved in the signaling pathways of TGF-βs induced myopia and axial elongation. Moreover, the expression levels of IL-6, IL-8, MCP-1, IL-1β, TNF-α, TAK1, and NF-κB in the retina were all significantly elevated. This indicates that TGF-β stimulates the inflammatory response of retinal pigment epithelial cells through the TAK1-NF-κB signaling pathway. In conclusion, this study suggests that TGF-β promotes the progression of myopia by enhancing intraocular inflammation.

Comparative Proteomic Analysis of Aqueous Humor Reveals Biochemical Disparities in the Eyes of High Myopic Patients

Myopia accounts for a significant proportion of visual lesions worldwide and has the potential to progress toward pathological myopia. This study aims to reveal the difference in protein content in aqueous humor between high myopic and nonhigh myopic patients, as well as better understand the dysregulation of proteins in myopic eyes. Aqueous humor was collected for liquid chromatograph mass spectrometer (LC/MS) analysis from 30 individual eyes that underwent phacoemulsification and intraocular lens (IOL) implantation. Results showed that a total of 190 differentially expressed proteins were identified, which revealed their involvement in cell metabolism, immune and inflammatory response, and system and anatomical structure. Further analysis focused on 15 intensively interacted hub proteins, encompassing functions related to complement cascades, lipoprotein metabolism, and fibrin biological function. Subsequent validations demonstrated elevated levels of APOE (apolipoprotein E), C3 (complement 3), and AHSG (α-2-HS-glycoprotein) in the high myopia group (31 eyes of cataracts and 45 eyes of high myopia with cataracts). AHSG had a significant positive correlation with axial length in high myopic patients, with good efficacy in distinguishing between myopic and nonmyopic groups. AHSG may be a potential indicator of the pathological severity and participator in the pathological progress of high myopia. This study depicted differential expression characteristics of aqueous humor in patients with high myopia and provided optional information for further experimental research on exploring the molecular mechanisms and potential therapeutic targets for high myopia. Data are available via ProteomeXchange with the identifier PXD047584.

Up-regulation of scleral C5b-9 and its regulation of the NLRP3 inflammasome in a form-deprivation myopia mouse model

BACKGROUND

Myopia has become a major public health problem worldwide. Although the involvement of the complement system in myopia progression has been reported, the underlying mechanism has not been well established. In this study, we induced a form deprivation (FD) myopia mouse model to investigate the mechanisms.

METHODS

Both C6-knockout (KO) and wild-type (WT) mice were divided into FD and normal control (NC) groups. The FD myopia was induced in the right eyes of 24-day-old mice using a translucent balloon for 4 weeks. The left eye remained untreated and served as self-control. NC group received no treatment. Refractive error and axial length were measured at baseline, 2 weeks, and 4 weeks later under normal visual, 4 weeks after FD. Scleral transcriptome sequencing analysis was performed in in FD mice. The scleral levels of C5b-9, NLRP3, Caspase-1, IL-1β, MMP-2, and collagen I were evaluated using immunohistochemistry.

RESULTS

RNA-seq analysis showed 1058 differentially expressed genes. The GO analysis showed these genes were mainly related to the extracellular matrix, and immune response. The KEGG enrichment analysis showed that complement cascades were upregulated. Under normal visual conditions, both genotypes of mice exhibited comparable refractive error and axial length. However, after four weeks of FD, C6-KO mice showed a significantly less myopic shift (-2.28 ± 0.28 D versus -5.40 ± 1.33 D, P = 0.003), and axial shift (0.043 ± 0.032 mm versus 0.083 ± 0.026 mm, P = 0.042) in comparison to WT mice. Furthermore, the levels of C5b-9, NLRP3, caspase-1, IL-1β, and MMP-2 were found to be elevated in the deprived eyes of WT mice in comparison to their fellow eyes, whereas the extent of this increase was significantly lower in C6-KO mice.

CONCLUSIONS

Complement cascades are activated in FD myopia model. Upregulation of C5b-9 might participate in scleral remodeling during myopia progression via regulation of NLRP3 inflammasome activation.

Insights into myopic choroidal neovascularization based on quantitative proteomics analysis of the aqueous humor

BACKGROUND

Previous studies on the biomarkers of pathologic myopia choroidal neovascularization (pmCNV) development merely detected limited types of proteins and provide a meagre illustration of the underlying pathways. Hence, a landscape of protein changes in the aqueous humor (AH) of pmCNV patients is lacking. Here, to explore the potential mechanisms and biomarkers of pmCNV, we analyzed the clinical data and protein profile among atrophic (A) lesions, tractional lesions (T) and neovascular (N) lesions in myopic patients based on the ATN grading system for myopic maculopathy (MM).

RESULTS

After investigating demographic data of our patients, a correlation was found between A and N lesions (R = 0.5753, P < 0.0001). Accordingly, groups were divided into patients without MM, patients with myopic atrophic maculopathy (MAM), and patients with pmCNV (N2a lesion). In proteomics analysis, the increased protein level of GFAP and complement-associated molecules in AH samples of the 3 groups also indicated that MAM and pmCNV shared similar characteristics. The GO enrichment and KEGG pathway analysis were performed, which mapped that differential expressed proteins mainly engaged in JAK-STAT pathway between the pmCNV group and two controls. Furthermore, we identified several potential biomarkers for pmCNV, including FCN3, GFAP, EGFR, SFRP3, PPP2R1A, SLIT2, and CD248.

CONCLUSIONS

Atrophic lesions under pathologic myopic conditions demonstrated similarities to neovascularization development. Potential biomarkers including GFAP were associated with the pathogenesis of pmCNV. In summary, our study provides new insights for further research on pmCNV development.

RNA-Sequencing Analysis Reveals the Role of Mitochondrial Energy Metabolism Alterations and Immune Cell Activation in Form-Deprivation and Lens-Induced Myopia in Mice

Myopia is a substantial global public health concern primarily linked to the elongation of the axial length of the eyeball. While numerous animal models have been employed to investigate myopia, the specific contributions of genetic factors and the intricate signaling pathways involved remain incompletely understood. In this study, we conducted RNA-seq analysis to explore genes and pathways in two distinct myopia-inducing mouse models: form-deprivation myopia (FDM) and lens-induced myopia (LIM). Comparative analysis with a control group revealed significant differential expression of 2362 genes in FDM and 503 genes in LIM. Gene Set Enrichment Analysis (GSEA) identified a common immune-associated pathway between LIM and FDM, with LIM exhibiting more extensive interactions. Notably, downregulation was observed in OxPhos complex III of FDM and complex IV of LIM. Subunit A of complex I was downregulated in LIM but upregulated in FDM. Additionally, complex V was upregulated in LIM but downregulated in FDM. These findings suggest a connection between alterations in energy metabolism and immune cell activation, shedding light on a novel avenue for understanding myopia's pathophysiology. Our research underscores the necessity for a comprehensive approach to comprehending myopia development, which integrates insights from energy metabolism, oxidative stress, and immune response pathways.

Pathogenesis of myopic choroidal neovascularization: A systematic review and meta-analysis

Myopic choroidal neovascularization (CNV) is a vision-threatening complication of high myopia. Here, we systematically review cohort, case-control, and cross-sectional studies in PubMed, Embase, and Web of Science, and summarize the associated factors of myopic CNV using meta-analysis where applicable. Among 1,333 records assessed, 50 were found eligible, all having a low-to-moderate risk of bias. Highly myopic eyes with CNV had a higher risk of lacquer cracks (odds ratio = 2.88) and patchy chorioretinal atrophy (odds ratio = 3.43) than those without. The mean posterior staphyloma height (µm) was greater in myopic CNV eyes than in highly myopic eyes without CNV (mean difference = 82.03). The thinning of choroidal thickness (µm) between myopic eyes with and without CNV differed significantly (mean difference = -47.76). The level of vascular endothelial growth factor (pg/ml) in the aqueous humor of myopic CNV eyes was significantly higher than in highly myopic eyes without CNV (mean difference = 24.98), the same as interleukin-8 (IL-8) (pg/ml, mean difference = 7.73). Single-nucleotide polymorphisms in the vascular endothelial growth factor, complement factor I, and collagen type VIII alpha 1 genes were associated with myopic CNV. We found that myopic CNV eyes have a higher ratio of lacquer cracks and patchy chorioretinal atrophy, thinner choroid, greater posterior staphyloma height, and a higher level of vascular endothelial growth factor and IL-8 in aqueous. Structural predisposing lesions, hemodynamic, genetic, and systemic factors are also associated with myopic CNV.

Effects of inflammation on myopia: evidence and potential mechanisms

As the most common type of refractive error, myopia has become one of the leading causes of visual impairment. With the increasing prevalence of myopia, there is a growing need to better understand the factors involved in its development. Inflammation, one of the most fundamental pathophysiological processes in humans, is a rapid response triggered by harmful stimuli and conditions. Although controlled inflammatory responses are necessary, over-activated inflammation is the common soil for many diseases. The impact of inflammation on myopia has received rising attention in recent years. Elevated inflammation may contribute to myopia progression either directly or indirectly by inducing scleral remodeling, and myopia development may also increase ocular inflammation. This article provides a comprehensive review of the interplay between inflammation and myopia and the potential biological mechanisms, which may present new targets for understanding the pathology of myopia and developing myopia therapies.

Cytological and functional effect of complement 3a on Human Scleral Fibroblasts

PURPOSE

The complement system is considered to play an important role in the progression of myopia, whereas the influence of complement activation on the human scleral fibroblasts (HSFs) remains unknown. Hence, the effect of complement 3a (C3a) on HSFs was investigated in this study.

METHODS

HSFs were cultured with exogenous C3a at 0.1 μM for various periods following different measurement protocols, and cells without C3a treatment served as negative control (NC). Cell viability was investigated using the MTS assay after 3 days of C3a treatment. Cell proliferation was evaluated by the 5-Ethynyl-20-Deoxyuridine (EdU) assay following C3a stimulation for 24 hours. Apoptosis was assessed by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining following C3a stimulation for 48 hours and the stained cells were analysed using flow cytometry. The levels of type I collagen and matrix metalloproteinase-2 (MMP-2) were analysed using ELISA following C3a stimulation for 36 and 60 hours. The level of CD59 were analysed using western blot following C3a stimulation for 60 hours.

RESULTS

The MTS assay revealed that cell viability was attenuated by 13% and 8% after C3a for 2 and 3 days, respectively (P < 0.05). The EdU assay demonstrated a 9% decrease in proliferation rate for the C3a-treated cells after 24 hours (P < 0.05). The apoptosis analysis revealed an increased percentage of cells in early apoptosis (P = 0.02) and total apoptosis (P = 0.02) in the C3a-treated group. Compared with NC group, the level of MMP-2 was increased by 17.6% (P = 0.002), whereas the levels of type I collagen and CD59 were respectively decreased by 12.5% (P = 0.024) and 21.6% (P = 0.044) with C3a treatment for 60 hours.

CONCLUSIONS

These results indicated that C3a-induced complement activation is potentially involved in inducing myopic-associated scleral extracellular matrix remodelling via mediating the proliferation and function of HSFs.

Complement-mediated inflammation and mitochondrial energy metabolism in the proteomic profile of myopic human corneas

Myopia is one of the most common causes of visual impairment worldwide. To identify proteins related to myopiagenesis, data-independent acquisition proteomic analysis was performed using corneal lenticules of myopic patients who underwent small incision lenticule extraction surgery. A total of 19 lenticules from 19 age and sex-matched patients were analyzed, 10 in high refractive error (HR, spherical equivalent over -6.00 D) group and 9 in low refractive error (LR, spherical equivalent between -3.00 and - 1.00 D) group. Differentially expressed proteins (DEPs) were identified by comparing the corneal proteome between the two groups. Functional analyses were performed to explore the biological pathways and interactions of the DEPs. 107 DEPs (67 upregulated and 40 downregulated in HR group, compared to LR) were identified from 2138 quantified proteins. Functional analyses indicated that upregulated proteins were primarily involved in the complement pathways and extracellular matrix (ECM) remodeling, while downregulated proteins were involved in mitochondrial energy metabolism. Western blot analysis confirmed increased complement C3a and apolipoprotein E in HR samples, further supporting the proteomics data. In conclusion, this proteomic study reveals that proteins associated with the complement system, ECM remodeling, and mitochondrial energy metabolism might be key effectors in myopiagenesis. SIGNIFICANCE: Myopia has become one of the most prevalent causes of visual impairment, especially in Asia. The underlying mechanism of myopia development is still up for debate. This study compares the proteomic profiles of high and low myopic corneas, identifying differentially expressed proteins associated with the complement system, ECM remodeling, and mitochondrial energy metabolism. The findings of this study could provide novel insights into the pathogenesis of myopia. The complement system and mitochondrial energy metabolism may provide potential therapeutic targets in the treatment and prevention of myopia.

Correlation between neutrophil-to-lymphocyte ratio and clinical manifestations and complications of retinitis pigmentosa

PURPOSE

The role of inflammation in retinitis pigmentosa (RP) has been receiving additional attention. However, the association between inflammation and the clinical manifestations and complications of RP is still unclear. This study aimed to evaluate the neutrophil-to-lymphocyte ratio (NLR) of RP complicated with cataract and explore the correlations between the NLR and specific clinical features of RP.

METHODS

This retrospective study included 79 RP patients complicated with cataract (125 eyes) and 63 age- and sex-matched patients (63 eyes) with age-related cataract (ARC). Patients' ocular examination results were collected and complete blood count results were used to calculate NLRs. The correlations between the NLR of RP patients and the parameters of ocular examinations were analysed.

RESULTS

The NLRs of RP patients with cataracts were significantly higher than those of ARC (1.93 ± 0.83 versus 1.65 ± 0.59, p = 0.029). The NLRs increased with the severity of posterior subcapsular cataract (PSC), zonular deficiency, poor preoperative best-corrected visual acuity (LogMAR>1), and visual field defects. Analysis of receiver operating characteristic curves suggested that NLR > 1.36 could predict higher degrees (PSC area >3%, >P1) of PSC (p = 0.002, 95% CI, 0.672-0.934), and that NLR > 2.12 could predict zonular weakness (p = 0.002, 95% CI, 0.665-0.928) in RP.

CONCLUSION

The NLRs in RP patients with cataract are not only higher but also associated with several clinical manifestations of RP. The NLR can be a predictive biomarker of higher degrees of PSC (>P1) and zonular weakness in RP before cataract surgery. These results suggest that systemic inflammation may play a role in the pathogenesis of RP.

Black carbon induces complement activation via NLRP3 inflammasome in human corneal epithelial cells

PURPOSE

To investigate the effect of black carbon (BC) particles on complement activation in human corneal epithelial cells (HCECs), and determine whether this effect can be attenuated by inhibiting the NLPR3 inflammasome pathway.

MATERIALS AND METHODS

HCECs were treated with fresh BC (FBC) or ozone-oxidized BC (OBC) particles at a concentration of 200 μg/ml for 72hours. Complement activation was observed by detecting C5b-9 protein level in cell culture supernatant using ELISA. HCECs were transfected with duplexes of siRNA targeting NLRP3 (NLRP3-siRNA) at 0.1 pmol/µL for 24 hours to inhibit the NLPR3 inflammasome pathway. RT-qPCR was performed to examine the efficacy of NLRP3-siRNA for inhibition; a random siRNA duplex was used for control siRNA.

RESULTS

Both FBC exposure and OBC exposure for 72 hours significantly increased the C5b-9 protein level compared to negative control cells (all P < .05). However, the difference in C5b-9 level after FBC exposure and OBC exposure was not statistically significant (P> .05). NLRP3-siRNA transfection reduced C5b-9 protein levels in FBC treated and OBC treated HCECs compared to control (lowered by 27% in the FBC treated group and by 23% in the OBC treated group, all P < .05).

CONCLUSIONS

BC particles, including FBC and OBC, triggered complement activation, increasing the protein level of C5b-9 in cultured HCECs. siRNA targeting NLRP3 to inhibit NLRP3 generation reduced C5b-9 protein level in HCECs treated with FBC or OBC particles, indicating that BC induces complement activation potentially through the NLRP3 inflammasome in HCECs.

Nonsteroidal anti-inflammatory drugs for retinal neurodegenerative diseases

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most common prescription drugs for inflammation, and topical NSAIDs are often used in ophthalmology to reduce pain, photophobia, inflammation, and edema. In recent years, many published reports have found that NSAIDs play an important role in the treatment of retinal neurodegenerative diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma, pathological myopia, and retinitis pigmentosa (RP). The aim of the current review is to provide an overview of the role of various NSAIDs in the treatment of retinal neurodegenerative diseases and the corresponding mechanisms of action. This review highlighted that the topical application of NSAIDs for the treatment of retinal degenerative diseases has been studied to a remarkable extent and that its beneficial effects in many diseases have been proven. In the future, prospective studies with large study populations are required to extend these effects to clinical settings.

RNA-seq and GSEA identifies suppression of ligand-gated chloride efflux channels as the major gene pathway contributing to form deprivation myopia

Currently there is no consensus regarding the aetiology of the excessive ocular volume that characterizes high myopia. Thus, we aimed to test whether the gene pathways identified by gene set enrichment analysis of RNA-seq transcriptomics refutes the predictions of the Retinal Ion Driven Efflux (RIDE) hypothesis when applied to the induction of form-deprivation myopia (FDM) and subsequent recovery (post-occluder removal). We found that the induction of profound FDM led to significant suppression in the ligand-gated chloride ion channel transport pathway via suppression of glycine, GABA_A and GABA_C ionotropic receptors. Post-occluder removal for short term recovery from FDM of 6 h and 24 h, induced significant upregulation of the gene families linked to cone receptor phototransduction, mitochondrial energy, and complement pathways. These findings support a model of form deprivation myopia as a Cl⁻ ion driven adaptive fluid response to the modulation of the visual signal cascade by form deprivation that in turn affects the resultant ionic environment of the outer and inner retinal tissues, axial and vitreal elongation as predicted by the RIDE model. Occluder removal and return to normal light conditions led to return to more normal upregulation of phototransduction, slowed growth rate, refractive recovery and apparent return towards physiological homeostasis.

Proteomic analysis of aqueous humor in patients with pathologic myopia

Complications from pathologic myopia (PM) are a major cause of visual impairment and blindness. However, an efficient clinical therapeutic strategy for PM is still lacking. The aim of this study was to quantitatively compare the proteomic profiles of aqueous humor between PM and non-PM cataract patients. Twenty aqueous humor samples from each group were analyzed with label-free quantitative proteomic analysis to identify the differentially expressed proteins for function enrichment analyses and protein-protein interaction network construction. Hub protein was validated with ELISA using an independent cohort consisting of 20 samples from each group and its receiver operating characteristic (ROC) curve analysis was conducted. A total of 583 proteins were identified and 101 proteins were found to be differentially expressed, including 63 up-regulated proteins and 38 down-regulated proteins. The bioinformatics analysis suggested that PM is closely associated with immunity and inflammation interactions, and remodeling of extracellular matrix. Apolipoprotein A-I (ApoA1) was enriched as the hub protein of the network with the highest score, degree and centrality. ROC analysis showed that ApoA1 could distinguish PM from controls with an area under the curve of 0.963 (p < 0.001). The findings could provide potential clues for further study on the molecular mechanisms and developing new treatments for PM, especially related to immunity and inflammation interactions. ApoA1 may be a potential key protein and therapeutic target in human PM. SIGNIFICANCE: It is important and urgent to discover the mechanisms of pathologic myopia (PM) to inhibit its progression. This study applied the quantitative proteomic analysis to study aqueous humor from patients with or without PM, aiming to discover dysregulated proteins related to PM. Our results suggested that those dysregulated proteins are closely associated with immunity and inflammation interactions, and remodeling of extracellular matrix. The findings from this study could provide potential clues for further research on the molecular mechanisms and developing new treatments for PM, especially related to immunity and inflammation. ApoA1 may be a potential key protein and therapeutic target in human PM.

Therapeutic Lessons to be Learned From the Role of Complement Regulators as Double-Edged Sword in Health and Disease

The complement system is an important part of the innate immune system, providing a strong defense against pathogens and removing apoptotic cells and immune complexes. Due to its strength, it is important that healthy human cells are protected against damage induced by the complement system. To be protected from complement, each cell type relies on a specific combination of both soluble and membrane-bound regulators. Their importance is indicated by the amount of pathologies associated with abnormalities in these complement regulators. Here, we will discuss the current knowledge on complement regulatory protein polymorphisms and expression levels together with their link to disease. These diseases often result in red blood cell destruction or occur in the eye, kidney or brain, which are tissues known for aberrant complement activity or regulation. In addition, complement regulators have also been associated with different types of cancer, although their mechanisms here have not been elucidated yet. In most of these pathologies, treatments are limited and do not prevent the complement system from attacking host cells, but rather fight the consequences of the complement-mediated damage, using for example blood transfusions in anemic patients. Currently only few drugs targeting the complement system are used in the clinic. With further demand for therapeutics rising linked to the wide range of complement-mediated disease we should broaden our horizon towards treatments that can actually protect the host cells against complement. Here, we will discuss the latest insights on how complement regulators can benefit therapeutics. Such therapeutics are currently being developed extensively, and can be categorized into full-length complement regulators, engineered complement system regulators and antibodies targeting complement regulators. In conclusion, this review provides an overview of the complement regulatory proteins and their links to disease, together with their potential in the development of novel therapeutics.

Update on Myopia Risk Factors and Microenvironmental Changes

The focus of this update is to emphasize the recent advances in the pathogenesis and various molecular key approaches associated with myopia in order to reveal new potential therapeutic targets. We review the current evidence for its complex genetics and evaluate the known or candidate genes and loci. In addition, we discuss recent investigations regarding the role of environmental factors. This paper also covers current research aimed at elucidating the signaling pathways involved in the pathogenesis of myopia.

The Relation of Neutrophil to Lymphocyte Ratio and Platelet to Lymphocyte Ratio with High Axial Myopia

Purpose: To investigate the relation between high axial myopia and neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) values.Methods: Seventy-nine cases were enrolled, 50 myopic and 29 emmetropic. All participants were assigned into three groups: Group I (high myopia with no retinal involvement), Group II (high myopia with retinal involvement) and Group III (control). NLR and PLR values calculated from blood tests were compared among the groups.Results: Mean NLR levels were 2.23 ± 0.78 in Group I, 2.36 ± 1.06 in Group II, and 1.57 ± 0.33 in Group III. Mean PLR levels were 114.62 ± 23.21 in Group I, 145.16 ± 52.36 in Group II, and 91.42 ± 18.73 in Group III. NLR and PLR values in the high myopia groups were significantly higher than in the control group.Conclusion: NLR and PLR values in cases with high axial myopia were higher than in the emmetropic group. Higher inflammation in the degenerative myopic group in particular may be related to pathological chorioretinal changes.

Scleral Cross-Linking Using Glyceraldehyde for the Prevention of Axial Elongation in the Rabbit: Blocked Axial Elongation and Altered Scleral Microstructure

BACKGROUND

This study aims to assess the efficacy of the scleral collagen cross-linking method using glyceraldehyde solution for prevention of lens-induced axial elongation in New Zealand rabbits and investigate the biochemical and microstructural changes that occur.

METHODS

The right eyes of New Zealand rabbits aged seven weeks were randomly divided into three groups: the cross-linking group (n = 6), non-crosslinking group (n = 5), and untreated control group (n = 5). Eyes in cross-linking and non-crosslinking groups were treated with a -8.00 Diopter spherical lens over the course of two weeks. The cross-linking effects were achieved by a sub-Tenon's injection of 0.15 ml 0.5 M glyceraldehyde to eyes in the CL group. Ocular parameters were measured on the 1st, 7^th, and 14th days. Biomechanical testing, light and electronic microscopy were used.

RESULTS

Following the cross-linking treatment, eyes in the cross-linking group had a shorter axial length compared to those in the non-crosslinking group (p = 0.006). Collagen fibrils larger than 240 nm were observed in the scleral stroma of cross-linking group, which were absent in the scleral stroma of the non-crosslinking and untreated control group. The mean ultimate stress and Young's modulus was significantly greater in the cross-linking group compared to those in the non-crosslinking and untreated control group (p < 0.05). No histological damage observed in the retina or choroid.

CONCLUSIONS

This study demonstrates that lens-induced axial elongation in rabbits can be effectively blocked by cross-linking using glyceraldehyde, with anatomical and mechanical modification and no deleterious effects.

Pathway analysis identifies altered mitochondrial metabolism, neurotransmission, structural pathways and complement cascade in retina/RPE/ choroid in chick model of form-deprivation myopia

Purpose

RNA sequencing analysis has demonstrated bidirectional changes in metabolism, structural and immune pathways during early induction of defocus induced myopia. Thus, the aim of this study was to investigate whether similar gene pathways are also related to the more excessive axial growth, ultrastructural and elemental microanalytic changes seen during the induction and recovery from form-deprivation myopia (FDM) in chicks and predicted by the RIDE model of myopia.

Methods

Archived genomic transcriptome data from the first three days of induction of monocularly occluded form deprived myopia (FDMI) in chicks was obtained from the GEO database (accession # GSE6543) while data from chicks monocularly occluded for 10 days and then given up to 24 h of normal visual recovery (FDMR) were collected. Gene set enrichment analysis (GSEA) software was used to determine enriched pathways during the induction (FDMI) and recovery (FDMR) from FD. Curated gene-sets were obtained from open access sources.

Results

Clusters of significant changes in mitochondrial energy metabolism, neurotransmission, ion channel transport, G protein coupled receptor signalling, complement cascades and neuron structure and growth were identified during the 10 days of induction of profound myopia and were found to correlate well with change in axial dimensions. Bile acid and bile salt metabolism pathways (cholesterol/lipid metabolism and sodium channel activation) were significantly upregulated during the first 24 h of recovery from 10 days of FDM.

Conclusions

The gene pathways altered during induction of FDM are similar to those reported in defocus induced myopia and are established indicators of oxidative stress, osmoregulatory and associated structural changes. These findings are also consistent with the choroidal thinning, axial elongation and hyperosmotic ion distribution patterns across the retina and choroid previously reported in FDM and predicted by RIDE.

Scleral ultrastructure and biomechanical changes in rabbits after negative lens application

AIM

To address the microstructure and biomechanical changes of the sclera of rabbits after negative lens application by spectacle frame apparatus.

METHODS

Five New Zealand rabbits of seven weeks post-natal were treated with -8 D lens monocularly over the course of two weeks. Refractive errors and axial length (AXL) were measured at the 1^st, 7^th and 14^th days of the induction period. Ultrastructure of sclera was determined with electron microscopy. Biomechanical properties were tested by an Instron 5565 universal testing machine.

RESULTS

Lens-induced (LI) eyes elongated more rapidly compared with fellow eyes with AXL values of 15.56±0.14 and 15.21±0.14 mm (P<0.01). Fibril diameter was significantly smaller in the LI eyes compared with control ones in the inner, middle, and outer layers (inner layer, 63.533 vs 76.467 nm; middle layer, 92.647 vs 123.984 nm; outer layer, 86.999 vs 134.257 nm, P<0.01, respectively). In comparison with control eyes, macrophage-like cells that engulfed fibroblasts, dilated endoplasmic reticulum, and vacuoles in fibroblasts were observed in the inner and middle stroma in the LI eyes. Ultimate stress and Young's modulus were lower in the LI eyes compared with those in the control eyes.

CONCLUSION

Negative lens application alters eye growth, and results in axial elongation with changes in scleral ultrastructural and mechanical properties.

C-Reactive protein and progression of vision loss in retinitis pigmentosa

PURPOSE

Chronic inflammation is involved in retinitis pigmentosa (RP). We demonstrated previously that intraocular inflammatory levels, as measured by slit-lamp ophthalmoscopy or laser flare photometry, are inversely correlated with central visual function in patients with RP. Here, we investigated the relationship between serum high-sensitivity C-reactive protein (hs-CRP) and visual parameters in RP.

METHODS

We studied 58 consecutive typical patients with RP <40 years old and 29 age- and gender-matched controls. High-sensitivity C-reactive protein (hs-CRP) was detected by immunoturbidimetry. The relationships between hs-CRP and visual parameters including best-corrected visual acuity (BCVA), mean deviation (MD) of static perimetry tests (Humphrey Field Analyzer, the central 10-2 programme) and VA changes over the prior 5 years and MD changes over the prior 3 years were analysed in the patients with RP.

RESULTS

The serum hs-CRP levels of the patients with RP were significantly higher than those of the controls (0.06 ± 0.08 versus 0.03 ± 0.04 mg/dl, p = 0.0119). In the patients with RP, there was no correlation of hs-CRP with cross-sectionally assessed VA or MD, but the baseline hs-CRP was significantly correlated with the MD deterioration (r = -0.4073, p = 0.0314).

CONCLUSION

The average serum hs-CRP was significantly increased in the patients with RP, and higher hs-CRP was associated with faster deterioration of central visual function. These results suggest that the systemic inflammatory profile is altered and may be associated with disease progression in RP.

Allergic Conjunctivitis-induced Retinal Inflammation Promotes Myopia Progression

Myopia is a highly prevalent eye disease. There is limited information suggesting a relationship between myopia and inflammation. We found children with allergic conjunctivitis (AC) had the highest adjusted odds ratio (1.75, 95% confidence interval [CI], 1.72-1.77) for myopia among the four allergic diseases. A cohort study was conducted and confirmed that children with AC had a higher incidence and subsequent risk of myopia (hazard ratio 2.35, 95%CI 2.29-2.40) compared to those without AC. Lower refractive error and longer axial length were observed in an AC animal model. Myopia progression was enhanced by tumor necrosis factor (TNF)-α or interleukin (IL)-6 administration, two cytokines secreted by mast cell degranulation. The TNF-α or IL-6 weakened the tight junction formed by corneal epithelial (CEP) cells and inflammatory cytokines across the layer of CEP cells, which increased the levels of TNF-α, IL-6, and IL-8 secreted by retinal pigment epithelial cells. The expression levels of TNF-α, IL-6, IL-8, monocyte chemoattractant protein-1, and nuclear factor kappa B were up-regulated in eyes with AC, whereas IL-10 and the inhibitor of kappa B were down-regulated. In conclusion, the experimental findings in mice corroborate the epidemiological data showing that allergic inflammation influences the development of myopia.

Novel evidence for complement system activation in chick myopia and hyperopia models: a meta-analysis of transcriptome datasets

Myopia (short-sightedness) and hyperopia (long-sightedness) occur when the eye grows too long or short, respectively, for its refractive power. There are currently approximately 1.45 billion myopes worldwide and prevalence is rising dramatically. Although high myopia significantly increases the risk of developing a range of sight-threatening disorders, the molecular mechanisms underlying ocular growth regulation and its relationship to these secondary complications remain poorly understood. Thus, this study meta-analyzed transcriptome datasets collected in the commonly used chick model of optically-induced refractive error. Fifteen datasets (collected across five previous studies) were obtained from GEO, preprocessed in Bioconductor, and divided into 4 conditions representing early (≤1 day) and late (>1 day) myopia and hyperopia induction. Differentially expressed genes in each condition were then identified using Rank Product meta-analysis. The results provide novel evidence for transcriptional activation of the complement system during both myopia and hyperopia induction, and confirm existing literature implicating cell signaling, mitochondrial, and structural processes in refractive error. Further comparisons demonstrated that the meta-analysis results also significantly improve concordance with broader omics data types (i.e., human genetic association and animal proteomics studies) relative to previous transcriptome studies, and show extensive similarities with the genes linked to age-related macular degeneration, choroidal neovascularization, and cataract.

C3a Increases VEGF and Decreases PEDF mRNA Levels in Human Retinal Pigment Epithelial Cells

Complement activation, specifically complement 3 (C3) activation and C3a generation, contributes to an imbalance between angiogenic stimulation by vascular endothelial growth factor (VEGF) and angiogenic inhibition by pigment epithelial derived factor (PEDF), leading to pathological angiogenesis. This study aimed to investigate the effects of C3a and small interfering RNA (siRNA) targeting C3 on the levels of VEGF and PEDF mRNAs in human retinal pigment epithelial (RPE) cells. ARPE-19 cells were cultured in the presence of exogenous C3a at 0.1 μM and 0.3 μM C3a for 24, 48, and 72 hours. 0.1 pmol/μL duplexes of siRNA targeting C3 were applied for C3a inhibition by transfecting ARPE-19 cells for 48 hours. RT-PCR was performed to examine the level of VEGF and PEDF mRNA. A random siRNA duplex was set for control siRNA. Results demonstrated that exogenous C3a significantly upregulated VEGF and downregulated PEDF mRNA levels in cultured ARPE-19 cells, and siRNA targeting C3 transfection reversed the above changes, significantly reducing VEGF and enhancing PEDF mRNAs level in ARPE-19 cells compared to the control. The present data provided evidence that reducing C3 activation can decreases VEGF and increase PEDF mRNA level in RPE and may serve as a potential therapy in pathological angiogenesis.

Bidirectional Expression of Metabolic, Structural, and Immune Pathways in Early Myopia and Hyperopia

Myopia (short-sightedness) affects 1.45 billion people worldwide, many of whom will develop sight-threatening secondary disorders. Myopic eyes are characterized by excessive size while hyperopic (long-sighted) eyes are typically small. The biological and genetic mechanisms underpinning the retina's local control of these growth patterns remain unclear. In the present study, we used RNA sequencing to examine gene expression in the retina/RPE/choroid across 3 days of optically-induced myopia and hyperopia induction in chick. Data were analyzed for differential expression of single genes, and Gene Set Enrichment Analysis (GSEA) was used to identify gene sets correlated with ocular axial length and refraction across lens groups. Like previous studies, we found few single genes that were differentially-expressed in a sign-of-defocus dependent manner (only BMP2 at 1 day). Using GSEA, however, we are the first to show that more subtle shifts in structural, metabolic, and immune pathway expression are correlated with the eye size and refractive changes induced by lens defocus. Our findings link gene expression with the morphological characteristics of refractive error, and suggest that physiological stress arising from metabolic and inflammatory pathway activation could increase the vulnerability of myopic eyes to secondary pathologies.

Complement factors C1q, C3 and C5b-9 in the posterior sclera of guinea pigs with negative lens-defocused myopia

AIM

To investigate the expression of complement factors in the posterior scleral fibroblasts of guinea pigs with negative lens-defocused myopia.

METHODS

Eighteen guinea pigs were assigned randomly to two groups: the negative lens-defocused group (NLD group, n=9) and the normal control without treatment group (NC group, n=9). The effect of myopic induction was compared in three subgroups: eyes treated with a -10.00 D negative lens in the NLD group (NL group), eyes treated with a plano (0 D) lens in the NLD group (PL group), and untreated right eyes in the NC group (NC group). The following analyses were conducted at four weeks: examination of the refractive error via retinoscopy, assessment of complement C5b-9 expression in the posterior scleral fibroblasts using immunohistochemistry, and measurements of complement C1q and C3 protein levels in the posterior sclera by Western blot.

RESULTS

After an induction period of four weeks, a significant myopic shift was detected in the eyes of the NL group, relative to that of the PL and NC groups (P<0.05). Data analysis showed a significant increase in the percentage of C5b-9 immunopositive fibroblasts in the posterior sclera of the NL group eyes, compared to the PL group (q=11.50, P<0.001). Significantly higher levels of C1q (q=4.94, P=0.01) and C3 (q=4.07, P=0.03) protein were detected in the posterior sclera of NL group eyes, compared to the PL group. There were no significant difference between the PL and NC groups for C5b-9 (q=2.44, P=0.10), C1q (q=1.55, P=0.53) and C3 (q=0.98, P=0.77) in the posterior sclera.

CONCLUSION

The data from present study provide evidence of the up-regulation of C5b-9, C1q and C3 in the posterior scleral fibroblasts in a NLD myopic animal model. The results suggest that the complement system may be involved in the development of myopia.