Immediate sequential bilateral cataract surgery: a 13-year real-life report of 56 700 cataract operations

BACKGROUND/AIMS

To assess the frequency of immediate sequential bilateral cataract surgery (ISBCS) and endophthalmitis during 13-year period in Tays Eye Centre, Tampere University Hospital, Tampere, Finland.

METHODS

All cataract surgeries performed between 1 January 2008 and 31 December 2020, and all endophthalmitis cases during the same period were searched from electronic patient records. Numbers and frequencies of ISBCS, and complications, including endophthalmitis and vitreous loss, were recorded and compared with unilateral operations.

RESULTS

The study included 56 700 cataract surgeries in 34 797 patients of whom 39% (n=13 445) had ISBCS. The median age of the patients was 75 (IQR 68-80, range 0.08-99) years at the time of surgery. The proportion of ISBCS patients increased from 4.2% in 2008 to 46% in 2020. Vitreous loss occurred in 480 (0.9%) of cataract surgeries. There were no postoperative endophthalmitis after cataract surgery (n=0) during the 13-year period.

CONCLUSION

The proportion of patients undergoing ISBCS increased from 4.2% in 2008 to 46% in 2020. No endophthalmitis were found to be associated with ISBCS.

Ten-year real-world outcomes of antivascular endothelial growth factor therapy in neovascular age-related macular degeneration using pro re nata regimen

BACKGROUND/AIMS

To analyse long-term outcomes of antivascular endothelial growth factor (anti-VEGF) therapy for the treatment of neovascular age-related macular degeneration (nAMD) using pro re nata (PRN) regimen in a single-centre clinical practice.

METHODS

All patients receiving intravitreal injection (IVI) for nAMD between 1 January 2008 and 31 December 2020 were searched from electronic medical records. All 3844 treatment-naïve eyes of 3008 patients were included with a total of 50 146 IVIs (87% bevacizumab) administered. Main outcome measures were mean change in visual acuity (VA) from baseline, proportion of eyes within 15 letters of baseline, proportion of eyes with VA ≥20/40 Snellen and ≤20/200 Snellen, number of annual visits and number of annual IVIs.

RESULTS

The mean baseline VA was 55 Early Treatment Diabetic Retinopathy Study (ETDRS) letters and the mean change in VA from baseline was +2, +2, ±0, -2, -2 and -4 ETDRS letters at year 1, 2, 3, 5, 7 and 10, respectively. Proportions of eyes within 15 letters of baseline were 88%, 87%, 82%, 80%, 76% and 72% at the end of years 1, 2, 3, 5, 7 and 10, respectively. The median number of annual IVI was 6 at years 1-7 and 5 at year 10. The median number of annual total visits was 10 at year 1, 9 at years 2-7 and 8 at year 10, respectively.

CONCLUSIONS

VA was maintained short-term and long-term with anti-VEGF therapy using PRN treatment regimen.

Proteomics Analysis of R-Ras Deficiency in Oxygen Induced Retinopathy

Small GTPase R-Ras regulates vascular permeability in angiogenesis. In the eye, abnormal angiogenesis and hyperpermeability are the leading causes of vision loss in several ischemic retinal diseases such as proliferative diabetic retinopathy (PDR), retinal vein occlusion (RVO), and retinopathy of prematurity (ROP). Oxygen-induced retinopathy (OIR) is the most widely used experimental model for these ischemic retinopathies. To shed more light on how the R-Ras regulates vascular permeability in pathological angiogenesis, we performed a comprehensive (>2900 proteins) characterization of OIR in R-Ras knockout (KO) and wild-type (WT) mice by sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomics. OIR and age-matched normoxic control retinas were collected at P13, P17, and P42 from R-Ras KO and WT mice and were subjected to SWATH-MS and data analysis. The most significant difference between the R-Ras KO and WT retinas was an accumulation of plasma proteins. The pathological vascular hyperpermeability during OIR in the R-Ras KO retina took place very early, P13. This led to simultaneous hypoxic cell injury/death (ferroptosis), glycolytic metabolism as well compensatory mechanisms to counter the pathological leakage from angiogenic blood vessels in the OIR retina of R-Ras deficient mice.

Selective Targeting and Tissue Penetration to the Retina by a Systemically Administered Vascular Homing Peptide in Oxygen Induced Retinopathy (OIR)

Pathological angiogenesis is the hallmark of ischemic retinal diseases among them retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR). Oxygen-induced retinopathy (OIR) is a pure hypoxia-driven angiogenesis model and a widely used model for ischemic retinopathies. We explored whether the vascular homing peptide CAR (CARSKNKDC) which recognizes angiogenic blood vessels can be used to target the retina in OIR. We were able to demonstrate that the systemically administered CAR vascular homing peptide homed selectively to the preretinal neovessels in OIR. As a cell and tissue-penetrating peptide, CAR also penetrated into the retina. Hyperoxia used to induce OIR in the retina also causes bronchopulmonary dysplasia in the lungs. We showed that the CAR peptide is not targeted to the lungs in normal mice but is targeted to the lungs after hyperoxia-/hypoxia-treatment of the animals. The site-specific delivery of the CAR peptide to the pathologic retinal vasculature and the penetration of the retinal tissue may offer new opportunities for treating retinopathies more selectively and with less side effects.

Pathological Angiogenesis Requires Syndecan-4 for Efficient VEGFA-Induced VE-Cadherin Internalization

[Figure: see text].

Oxygen-Induced Retinopathy Model for Ischemic Retinal Diseases in Rodents

One of the commonly used models for ischemic retinopathies is the oxygen-induced retinopathy (OIR) model. Here we describe detailed protocols for the OIR model induction and its readouts in both mice and rats. Retinal neovascularization is induced in OIR by exposing rodent pups either to hyperoxia (mice) or alternating levels of hyperoxia and hypoxia (rats). The primary readouts of these models are the size of neovascular (NV) and avascular (AVA) areas in the retina. This preclinical in vivo model can be used to evaluate the efficacy of potential anti-angiogenic drugs or to address the role of specific genes in the retinal angiogenesis by using genetically manipulated animals. The model has some strain and vendor specific variation in the OIR induction which should be taken into consideration when designing the experiments.

Exploration of Oxygen-Induced Retinopathy Model to Discover New Therapeutic Drug Targets in Retinopathies

Oxygen-induced retinopathy (OIR) is a pure hypoxia-driven angiogenesis model and the most widely used model for ischemic retinopathies, such as retinopathy of prematurity (ROP), proliferative diabetic retinopathy (PDR), and retinal vein occlusion (RVO). OIR model has been used to test new potential anti-angiogenic factors for human diseases. We have recently performed the most comprehensive characterization of OIR by a relatively novel mass spectrometry (MS) technique, sequential window acquisition of all theoretical fragment ion mass spectra (SWATH-MS) proteomics and used genetically modified mice strains to identify novel molecular drug targets in angiogenic retinal diseases. We have confirmed the relevance of the identified molecular targets to human diseases by determining their expression pattern in neovascular membranes obtained from PDR and RVO patients. Based on our results, crystallins were the most prominent proteins induced by early hypoxic environment during the OIR, while actomyosin complex and Filamin A-R-Ras axis, that regulates vascular permeability of the angiogenic blood vessels, stood out at the peak of angiogenesis. Our results have revealed potential new therapeutic targets to address hypoxia-induced pathological angiogenesis and the associated vascular permeability in number of retinal diseases.

Expression of VEGFA-regulating miRNAs and mortality in wet AMD

MicroRNAs (miRNAs) regulate gene expression; many of them act in the retinal pigment epithelium (RPE), and RPE degeneration is known to be a critical factor in age‐related macular degeneration (AMD). Repeated injections with anti‐VEGFA (vascular endothelial growth factor A) are the only effective therapy in wet AMD. We investigated the correlation between the expression of 18 miRNAs involved in the regulation of the VEGFA gene in serum of 76 wet AMD patients and 70 controls. Efficacy of anti‐VEGFA treatment was evaluated by counting the number of injections delivered up to 12 years. In addition, we compared the relative numbers of deaths in patient with AMD and control groups. We observed a decreased expression of miR‐34‐5p, miR‐126‐3p, miR‐145‐5p and miR‐205‐5p in wet AMD patients as compared with controls. These miRNAs are involved in the regulation of angiogenesis, cytoprotection and protein clearance. No miRNA was significantly correlated with the treatment outcome. Wet AMD patients had greater mortality than controls, and their survival was inversely associated with the number of anti‐VEGFA injections per year. No association was observed between miRNA expression and mortality. Our study emphasizes the need to clarify the role of miRNA regulation in AMD pathogenesis.

Viability of Mouse Retinal Explant Cultures Assessed by Preservation of Functionality and Morphology

Purpose

Retinal explant cultures provide simplified systems where the functions of the retina and the effects of ocular therapies can be studied in an isolated environment. The purpose of this study was to provide insight into long-term preservation of retinal tissue in culture conditions, enable a deeper understanding of the interdependence of retinal morphology and function, and ensure the reliability of the explant technique for prolonged experiments.

Methods

Retinal explants from adult mice were cultured as organotypic culture at the air-medium interface for 14 days in vitro (DIV). Retinal functionality was assessed by multielectrode array technique and morphology by immunohistochemical methods at several time points during culture.

Results

Retinal explants retained viability for 14 DIV, although with diminishing neuronal activity, progressing neuronal loss, and increasing reactive gliosis. We recorded spontaneous retinal ganglion cell (RGC) activity up to 14 DIV with temporally changing distribution of RGC firing rates. Light responsiveness was measurable from RGCs for 7 DIV and from photoreceptors for 2 DIV. Apoptotic cells were detected beginning at 3 DIV with their density peaking at 7 DIV. The number of RGCs gradually decreased by 70% during 14 DIV. The change was accompanied by the loss of RGC functionality, resulting in 84% loss of electrically active RGCs.

Conclusions

Retinal explants provide a valuable tool for studies of retinal functions and development of ocular therapies. However, critical for long-term use, retinal functionality was lost before structural loss, emphasizing a need for both functional and morphologic readouts to determine the overall state of the cultured retina.

SWATH-MS Proteomic Analysis of Oxygen-Induced Retinopathy Reveals Novel Potential Therapeutic Targets

Purpose

Oxygen-induced retinopathy (OIR) is the most widely used model for ischemic retinopathies such as retinopathy of prematurity (ROP), proliferative diabetic retinopathy (PDR), and retinal vein occlusion (RVO). The purpose of this study was to perform the most comprehensive characterization of OIR by a recently developed technique, sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomics.

Methods

Control and OIR retina samples collected from various time points were subjected to SWATH-MS and detailed data analysis. Immunohistochemistry from mouse retinas as well as neovascular membranes from human PDR and RVO patients were used for the detection of the localization of the proteins showing altered expression in the retina and to address their relevance to human ischemic retinopathies.

Results

We report the most extensive proteomic profiling of OIR to date by quantifying almost 3000 unique proteins and their expression differences between control and OIR retinas. Crystallins were the most prominent proteins induced by hypoxia in the retina, while angiogenesis related proteins such as Filamin A and nonmuscle myosin IIA stand out at the peak of angiogenesis. Majority of the changes in protein expression return to normal at P42, but there is evidence to suggest that proteins involved in neurotransmission remain at reduced level.

Conclusions

The results reveal new potential therapeutic targets to address hypoxia-induced pathological angiogenesis taking place in number of retinal diseases. The extensive proteomic profiling combined with pathway analysis also identifies novel molecular networks that could contribute to the pathogenesis of retinal diseases.

R-Ras regulates vascular permeability, but not overall healing in skin wounds

Wounds close by keratinocytes migrating from the edge of the wound and re-epithelializing the epidermis. It has been proposed that the major stimuli for wound closure are blood-derived growth factors, chemokines and cytokines. The small GTPase R-Ras, a known integrin activator, also regulates vascular permeability during angiogenesis, and blood vessels lacking R-Ras leak plasma proteins constantly. We explored whether the access to blood-derived proteins influences skin wound healing in R-Ras knockout (KO) mice. In skin wounds, R-Ras expression was mostly restricted to the vasculature in the granulation tissue. Angiogenic blood vessels in the R-Ras KO mice were significantly more permeable than in wild-type (WT) controls. Although the distances between epidermal tongues, and the panniculus carnosus muscles, were significantly longer in R-Ras KO than WT controls before the granulation tissue formation took place, there were no differences in the wound closure or re-epithelialization rates or granulation tissue formation. These findings were also corroborated in a special splint excision wound model. Our study shows that although R-Ras does not influence the skin wound healing itself, the blood vessels lacking R-Ras are leaky and thus could facilitate the access of blood-derived proteins to the wound.

Functional Voltage-Gated Calcium Channels Are Present in Human Embryonic Stem Cell-Derived Retinal Pigment Epithelium

Retinal pigment epithelium (RPE) performs important functions for the maintenance of photoreceptors and vision. Malfunctions within the RPE are implicated in several retinal diseases for which transplantations of stem cell‐derived RPE are promising treatment options. Their success, however, is largely dependent on the functionality of the transplanted cells. This requires correct cellular physiology, which is highly influenced by the various ion channels of RPE, including voltage‐gated Ca²⁺ (Ca_V) channels. This study investigated the localization and functionality of Ca_V channels in human embryonic stem cell (hESC)‐derived RPE. Whole‐cell patch‐clamp recordings from these cells revealed slowly inactivating L‐type currents comparable to freshly isolated mouse RPE. Some hESC‐RPE cells also carried fast transient T‐type resembling currents. These findings were confirmed by immunostainings from both hESC‐ and mouse RPE that showed the presence of the L‐type Ca²⁺ channels Ca_V1.2 and Ca_V1.3 as well as the T‐type Ca²⁺ channels Ca_V3.1 and Ca_V3.2. The localization of the major subtype, Ca_V1.3, changed during hESC‐RPE maturation co‐localizing with pericentrin to the base of the primary cilium before reaching more homogeneous membrane localization comparable to mouse RPE. Based on functional assessment, the L‐type Ca²⁺ channels participated in the regulation of vascular endothelial growth factor secretion as well as in the phagocytosis of photoreceptor outer segments in hESC‐RPE. Overall, this study demonstrates that a functional machinery of voltage‐gated Ca²⁺ channels is present in mature hESC‐RPE, which is promising for the success of transplantation therapies. stem cells translational medicine2019;8:179&15

Furin deficiency in myeloid cells leads to attenuated revascularization in a mouse-model of oxygen-induced retinopathy

Ischemic retinopathy is a vision-threatening disease associated with chronic retinal inflammation and hypoxia leading to abnormal angiogenesis. Furin, a member of the proprotein convertase family of proteins, has been implicated in the regulation of angiogenesis due to its essential role in the activation of several angiogenic growth factors, including vascular endothelial growth factor-C (VEGF-C), VEGF-D and transforming growth factor - β (TGF- β). In the present study, we evaluated expression of furin in the retina and its role in retinal angiogenesis. As both inflammation and hypoxia contribute to angiogenesis, the role of furin was evaluated using myeloid-cell specific furin knockout (KO) mice (designated LysMCre-fur^(fl/fl)) both in developmental retinal angiogenesis as well as in hypoxia-driven angiogenesis using the oxygen-induced retinopathy (OIR) model. In the retina, furin expression was detected in endothelial cells, macrophages and, to some extent, in neurons. The rate of angiogenesis was not different in LysMCre-fur^(fl/fl) mice when compared to their wild-type littermates during development. In the OIR model, the revascularization of retina was significantly delayed in LysMCre-fur^(fl/fl) mice compared to their wild-type littermates, while there was no compensatory increase in the preretinal neovascularization in LysMCre-fur^(fl/fl) mice. These results demonstrate that furin expression in myeloid cells plays a significant role in hypoxia-induced angiogenesis in retina.

The Finnish national guideline for diagnosis, treatment and follow-up of patients with wet age-related macular degeneration

Age-related macular degeneration (AMD) is the main cause of visual impairment in developed countries. Several improvements in the visualization of posterior segment of the eye together with the introduction of intravitreal anti-VEGF treatment have revolutionized the prognosis of the wet form of AMD (wAMD). Increasing incidence of wAMD together with the limited resources of society and of the healthcare system poses challenges for the provision and development of care. In context of these current aspects, we aimed to set evidence-based medical guidelines for diagnosis, treatment and follow-up of patients with wAMD.

R-Ras deficiency does not affect papain-induced IgE production in mice

Introduction

R‐Ras GTPase has recently been implicated in the regulation of immune functions, particularly in dendritic cell (DC) maturation, immune synapse formation, and subsequent T cell responses.

Methods

Here, we investigated the role of R‐Ras in allergen‐induced immune response (type 2 immune response) in Rras deficient (R‐Ras KO) and wild type (WT) mice.

Results

Initially, we found that the number of conventional DC's in the lymph nodes (LNs) was reduced in R‐Ras KO mice. The expression of co‐stimulatory CD80 and CD86 molecules on these cells was also reduced on DC's from the R‐Ras KO mice. However, there was no difference in papain‐induced immune response between the R‐Ras WT and KO as measured by serum IgE levels after the immunization. Interestingly, neither the DC number nor co‐stimulatory molecule expression was different between WT and R‐Ras KO animals after the immunization.

Conclusions

Taken together, despite having reduced number of conventional DC's in the R‐Ras KO mice and low expression of CD80 on DC's, the R‐Ras KO mice are capable of mounting papain‐induced IgE responses comparable to that of the WT mice. To our knowledge, this is the first report addressing potential differences in in vivo allergen responses regulated by the R‐Ras GTPase.

T-cell-expressed proprotein convertase FURIN inhibits DMBA/TPA-induced skin cancer development

Proprotein convertases (PCSK) have a critical role in the body homeostasis as enzymes responsible for processing precursor proteins into their mature forms. FURIN, the first characterized member of the mammalian PCSK family, is overexpressed in multiple malignancies and the inhibition of its activity has been considered potential cancer treatment. FURIN has also an important function in the adaptive immunity, since its deficiency in T cells causes an impaired peripheral immune tolerance and accelerates immune responses. We addressed whether deleting FURIN from the immune cells would strengthen anticancer responses by subjecting mouse strains lacking FURIN from either T cells or macrophages and granulocytes to the DMBA/TPA two-stage skin carcinogenesis protocol. Unexpectedly, deficiency of FURIN in T cells resulted in enhanced and accelerated development of tumors, whereas FURIN deletion in macrophages and granulocytes had no effect. The epidermises of T-cell-specific FURIN deficient mice were significantly thicker with more proliferating Ki67+ cells. In contrast, there were no differences in the numbers of the T cells. The flow cytometric analyses of T-cell populations in skin draining lymph nodes showed that FURIN T-cell KO mice have an inherent upregulation of early activation marker CD69 as well as more CD4⁺CD25⁺Foxp3⁺ positive T regulatory cells. In the early phase of tumor promotion, T cells from the T-cell-specific FURIN knockout animals produced more interferon gamma, whereas at later stage the production of Th2- and Th17-type cytokines was more prominent than in wild-type controls. In conclusion, while PCSK inhibitors are promising therapeutics in cancer treatment, our results show that inhibiting FURIN specifically in T cells may promote squamous skin cancer development.

Lack of R-Ras Leads to Increased Vascular Permeability in Ischemic Retinopathy

Purpose

The role of R-Ras in retinal angiogenesis and vascular permeability was evaluated in an oxygen-induced retinopathy (OIR) model using R-Ras knockout (KO) mice and in human diabetic neovascular membranes.

Methods

Mice deficient for R-Ras and their wild-type (WT) littermates were subjected to 75% oxygen from postnatal day 7 (P7) to P12 and then returned to room air. At P17 retinal vascularization was examined from whole mounts, and retinal vascular permeability was studied using Miles assay. Real-time RT-PCR, Western blotting, and immunohistochemistry were used to assess the expression of R-Ras in retina during development or in the OIR model. The degree of pericyte coverage and vascular endothelial (VE)-cadherin expression on WT and R-Ras KO retinal blood vessels was quantified using confocal microscopy. The correlation of R-Ras with vascular endothelial growth factor receptor 2 (VEGFR2) and human serum albumin on human proliferative diabetic retinopathy membranes was assessed using immunohistochemistry.

Results

In retina, R-Ras expression was mostly restricted to the vasculature. Retinal vessels in the R-Ras KO mice were significantly more permeable than WT controls in the OIR model. A significant reduction in the direct physical contact between pericytes and blood vessel endothelium as well as reduced VE-cadherin immunostaining was found in R-Ras–deficient mice. In human proliferative diabetic retinopathy neovascular membranes, R-Ras expression negatively correlated with increased vascular leakage and expression of VEGFR2, a marker of blood vessel immaturity.

Conclusions

Our results suggest that R-Ras has a role in controlling retinal vessel maturation and stabilization in ischemic retinopathy and provides a potential target for pharmacologic manipulation to treat diabetic retinopathy.

LDLR-/-ApoB100/100 mice with insulin-like growth factor II overexpression reveal a novel form of retinopathy with photoreceptor atrophy and altered morphology of the retina

PURPOSE

The aim of this study was to characterize the ocular morphology of low-density lipoprotein receptor-deficient apolipoprotein B-100-only mice, where overexpression of insulin-like growth factor II (IGF-II) has been shown to induce glucose intolerance and increase atherosclerotic lesion progression and calcification.

METHODS

Fifteen-month-old mice were examined on a normal chow diet and after 3 months of a high-fat Western diet. IGF-II-negative LDLR(-/-)ApoB(100/100) littermates and C57Bl/6J mice served as controls. In vivo color images of the fundi were obtained, and eyes were processed either for retinal flat mounts for assessment of neovascularization or for paraffin-embedded samples for immunohistochemical analyses.

RESULTS

IGF-II overexpression and the resulting prediabetic phenotype did not induce microvascular damage when assessed in fundus photographs and retinal whole mounts, and the number of capillaries in IGF-II/LDLR(-/-)ApoB(100/100) mice was not significantly different from LDLR(-/-)ApoB(100/100) mice. However, morphology of the inner nuclear, outer plexiform, and outer nuclear layers was altered in the IGF-II/LDLR(-/-)ApoB(100/100) mice. Moreover, photoreceptor atrophy and thinning of the outer nuclear layer were present. Caspase-3 staining was positive in the photoreceptor inner segment. In addition, retinas of the IGF-II/LDLR(-/-)ApoB(100/100) mice displayed reduced rhodopsin positivity, consistent with the decreased number of photoreceptor cells.

CONCLUSIONS

This study reports a novel form of retinopathy with photoreceptor atrophy and abundant changes in retinal morphology in a mouse model of prediabetes and atherosclerosis.

Snorc is a novel cartilage specific small membrane proteoglycan expressed in differentiating and articular chondrocytes

OBJECTIVE

Maintenance of chondrocyte phenotype is a major issue in prevention of degeneration and repair of articular cartilage. Although the critical pathways in chondrocyte maturation and homeostasis have been revealed, the in-depth understanding is deficient and novel modifying components and interaction partners are still likely to be discovered. Our focus in this study was to characterize a novel cartilage specific gene that was identified in mouse limb cartilage during embryonic development.

METHODS

Open access bioinformatics tools and databases were used to characterize the gene, predicted protein and orthologs in vertebrate species. Immunohistochemistry and mRNA expression methodology were used to study tissue specific expression. Fracture callus and limb bud micromass culture were utilized to study the effects of BMP-2 during experimental chondrogenesis. Fusion protein with C-terminal HA-tag was expressed in Cos7 cells, and the cell lysate was studied for putative glycosaminoglycan attachment by digestion with chondroitinase ABC and Western blotting.

RESULTS

The predicted molecule is a small, 121 amino acids long type I single-pass transmembrane chondroitin sulfate proteoglycan, that contains ER signal peptide, lumenal/extracellular domain with several threonines/serines prone to O-N-acetylgalactosamine modification, and a cytoplasmic tail with a Yin-Yang site prone to phosphorylation or O-N-acetylglucosamine modification. It is highly conserved in mammals with orthologs in all vertebrate subgroups. Cartilage specific expression was highest in proliferating and prehypertrophic zones during development, and in adult articular cartilage, expression was restricted to the uncalcified zone, including chondrocyte clusters in human osteoarthritic cartilage. Studies with experimental chondrogenesis models demonstrated similar expression profiles with Sox9, Acan and Col2a1 and up-regulation by BMP-2. Based on its cartilage specific expression, the molecule was named Snorc, (Small NOvel Rich in Cartilage).

CONCLUSION

A novel cartilage specific molecule was identified which marks the differentiating chondrocytes and adult articular chondrocytes with possible functions associated with development and maintenance of chondrocyte phenotype.