HIF-1α-dependent upregulation of angiogenic factors by mechanical stimulation in retinal pigment epithelial cells

Mechanical stimulation as a mimic of drusen formation in the eye increases the expression of angiogenic factors in retinal pigment epithelial (RPE) cells, but the underlying molecular mechanisms remain unclear. We investigated and characterized the effects of mechanical stimulation on the expression of angiogenic factors in RPE cells both in vitro and in a mouse model. Mechanical stimulation increased the expression of vascular endothelial growth factor (VEGF, encoded by VEGFA) and other angiogenesis-related genes in cultured RPE1 cells. The presence of hypoxia-inducible factor 1α (HIF-1α, encoded by HIF1A) was also increased, and both knockdown of HIF-1α and treatment with the HIF-1α inhibitor CAY10585 attenuated the effect of mechanical stimulation on angiogenesis factor gene expression. Signaling by the tyrosine kinase SRC and p38 mitogen-activated protein kinase was involved in HIF-1α activation and consequent angiogenesis-related gene expression induced by mechanical stimulation. Our results suggest that SRC-p38 and HIF-1α signaling are involved in the upregulation of angiogenic factors in RPE cells by mechanical stimulation. Such in vivo suppression of upregulated expression of angiogenesis-related genes by pharmacological inhibitors of HIF-1α suggests a new potential approach to the treatment of age-related macular degeneration.

Characterization of the visually impaired patients with diabetes mellitus in Japan

AIMS/INTRODUCTION

To conduct a multicenter survey of visually impaired patients with diabetes mellitus (DM) and to identify the physical and ocular characteristics that lead to blindness in Japan.

MATERIALS AND METHODS

Visually impaired patients with diabetes mellitus in Japan were divided into blind and low-vision groups according to the World Health Organization classification. Data on parameters related to diabetes mellitus and ocular complications in the right and left eyes were collected from 19 highly advanced medical facilities and compared between the two groups.

RESULTS

Among 408 visually impaired persons (blind group: 257, low-vision group: 151), 72.1% were under 70 years of age. The rates of neovascular glaucoma (NVG) (right eye, P = 0.041; left eye, P = 0.0031) or proliferative diabetic retinopathy (PDR) (right eye: P = 0.014, left eye: P = 0.0047) and the rate of proliferative membrane beyond half of the retinal area (right eye: P = 0.0263, left eye: P = 0.037) were significantly higher in the blind group. The direct cause of visual impairment was retinal atrophy, common in both groups. Neovascular glaucoma and diabetic macular edema were equally prevalent in the blind and low-vision groups, respectively.

CONCLUSIONS

In Japan, blind patients with diabetes mellitus are characterized by severe conditions such as neovascular glaucoma and progressive proliferative diabetic retinopathy upon their initial visit to an advanced care facility. These results highlight the importance of monitoring retinopathy through regular ophthalmological examinations, internal medicine, and appropriate therapeutic intervention.

SARS-CoV-2 infection status in corneal preservation solution and COVID-19 prevalence after corneal transplantation

The potential risks associated with organs from COVID-19-infected donors were unclear. To determine the SARS-CoV-2 infection status of corneas transplanted during the COVID-19 pandemic, we performed a polymerase chain reaction (PCR) using the corneal preservation solution that was used for corneal transplantation. We also examined the postoperative health status of the recipients. This study included 144 transplants in 143 eyes. Ninety-nine eyes of imported corneas and 10 of the 14 corneas donated in the prefecture were PCR tested at our hospital, and all were SARS-CoV-2 negative. All corneal transplants were performed after confirming their SARS-CoV-2 negativity by a PCR using a corneal preservation solution at our hospital or a nasopharyngeal swab at a previous facility. Despite postoperative steroid administration, no patient developed COVID-19 infection until discharge. Hence, if the donor's nasopharyngeal swab test is SARS-CoV-2 negative, COVID-19 infection in the recipient due to corneal transplantation may be prevented. Since corneal transplant recipients are susceptible to infection due to prolonged steroid administration and are at high risk for severe diseases if infection occurs, SARS-CoV-2 detection testing using nasopharyngeal swabs in donors should be performed.

Combination of blockade of endothelin signalling and compensation of IGF1 expression protects the retina from degeneration

Retinitis pigmentosa (RP) and macular dystrophy (MD) cause severe retinal dysfunction, affecting 1 in 4000 people worldwide. This disease is currently assumed to be intractable, because effective therapeutic methods have not been established, regardless of genetic or sporadic traits. Here, we examined a RP mouse model in which the Prominin-1 (Prom1) gene was deficient and investigated the molecular events occurring at the outset of retinal dysfunction. We extracted the Prom1-deficient retina subjected to light exposure for a short time, conducted single-cell expression profiling, and compared the gene expression with and without stimuli. We identified the cells and genes whose expression levels change directly in response to light stimuli. Among the genes altered by light stimulation, Igf1 was decreased in rod photoreceptor cells and astrocytes under the light-stimulated condition. Consistently, the insulin-like growth factor (IGF) signal was weakened in light-stimulated photoreceptor cells. The recovery of Igf1 expression with the adeno-associated virus (AAV) prevented photoreceptor cell death, and its treatment in combination with the endothelin receptor antagonist led to the blockade of abnormal glial activation and the promotion of glycolysis, thereby resulting in the improvement of retinal functions, as assayed by electroretinography. We additionally demonstrated that the attenuation of mammalian/mechanistic target of rapamycin (mTOR), which mediates IGF signalling, leads to complications in maintaining retinal homeostasis. Together, we propose that combinatorial manipulation of distinct mechanisms is useful for the maintenance of the retinal condition.

Exacerbation of Diabetic Retinopathy following Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitor Administration: A Case Report

Introduction

Hypoxia-inducible factor-prolyl hydroxylase (HIF-PH) inhibitors, used in the treatment of renal anemia, hold the potential to increase the production of vascular endothelial growth factors. Therefore, HIF-PH inhibitors may exacerbate retinal hemorrhage in diseases such as diabetic retinopathy. Here, we present a case involving the administration of an HIF-PH inhibitor, resulting in the exacerbation of retinal hemorrhage in a patient with diabetic retinopathy.

Case Presentation

A 32-year-old man with diabetes mellitus and renal anemia caused by diabetic nephropathy was referred to our department for ophthalmic examination, revealing diabetic retinopathy with scattered retinal hemorrhages, exudates, and diabetic maculopathy in both eyes. Darbepoetin alfa was initially administered and switched to the HIF-PH inhibitor roxadustat on day 74. By day 88, fresh retinal hemorrhage was observed in the right eye. On day 132, the retinal hemorrhage had further worsened, with new preretinal hemorrhage in both eyes. Roxadustat was discontinued, replaced with darbepoetin alfa, resulting in retinal hemorrhage improvement by day 181 (49 days post-roxadustat cessation). On day 201, fundus hemorrhage further improved, optical coherence tomography showed no macular edema or subretinal fluid, and the retina was thinning. Fluorescein angiography showed neovascular vessels, active fluorescein leakage, and extensive avascular areas in both eyes, prompting pan-retinal photocoagulation. Visual acuity remained stable throughout treatment.

Conclusion

Patients with advanced diabetic retinopathy taking HIF-PH inhibitors should be aware of retinal hemorrhage exacerbations. If observed, the treatment plan, including discontinuation of the HIF-PH inhibitor or switching to another agent, should be discussed with a diabetologist, nephrologist, and ophthalmologist.

Treatment of Failure of Macular Hole Closure due to Post-Vitrectomy Macular Edema Using Sub-Tenon Triamcinolone Acetonide Injection: A Case Report

Introduction

Post-vitrectomy cystoid macular edema (CME) can lead to failure of macular hole (MH) closure. We report 2 cases of failure of MH closure due to post-vitrectomy CME, which were successfully treated using sub-Tenon triamcinolone acetonide (STTA) injection.

Case Presentations

Case 1 involved a 72-year-old male patient with a Gass Stage 3 MH in the right eye. He underwent pars plana vitrectomy (PPV), internal limiting membrane translocation, and sulfur hexafluoride (SF6) gas injection with cataract surgery in his right eye. The MH did not close postoperatively; further, CME developed at the edge of the MH. Accordingly, the patient underwent an STTA injection. Approximately 2 weeks after the STTA injection, the CME disappeared and the MH closed, which has remained closed 1 year after PPV. Case 2 involved a 78-year-old female patient with Gass Stage 3 MH in the left eye. The patient underwent the same surgical procedure as that performed in case 1. Further, she presented with failure of MH closure caused by CME; therefore, an STTA injection was performed. Approximately 6 weeks after STTA injection, the CME disappeared and the MH closed; further, there was maintained improvement of best-corrected visual acuity for 6 months.

Conclusions

STTA injection could be considered before reoperation in cases involving failure of MH closure due to postoperative CME.

Prominin-1 deletion results in spermatogenic impairment, sperm morphological defects, and infertility in mice

Purpose

Spermatogenesis is a complex process orchestrated by several essential genes. Prominin-1 (Prom1/PROM1) is a gene that is expressed in the testis but with a poorly understood role in spermatogenesis.

Methods

We used Prom1 knockout (Prom1 KO) mice to assess the role of Prom1 in spermatogenesis. To this end, we performed immunohistochemistry, immunofluorescence, western blotting, β-galactosidase staining, and apoptosis assay. Additionally, we analyzed the morphology of sperm and assessed litter sizes.

Results

We observed that PROM1 is localized to the dividing spermatocytes in seminiferous epithelial cells, sperm, and columnar epithelium in the epididymis. In the Prom1 KO testis, an aberrant increase in apoptotic cells and a decrease in proliferating seminiferous epithelial cells were observed. Cellular FLICE-like inhibitory protein (c-FLIP) and extracellular signal-regulated kinase 1/2 (ERK1/2) expression were also significantly decreased in Prom1 KO testis. In addition, a significantly increased number of epididymal spermatozoa with abnormal morphology and less motility was found in Prom1 KO mice.

Conclusions

PROM1 maintains spermatogenic cell proliferation and survival via c-FLIP expression in the testis. It is also involved in sperm motility and fertilization potential. The mechanism underlying the effect of Prom1 on sperm morphology and motility remains to be identified.

Role of CRP2-MRTF interaction in functions of myofibroblasts

Inflammatory response induces phenotypic modulation of fibroblasts into myofibroblasts. Although transforming growth factor-βs (TGF-βs) evoke such transition, the details of the mechanism are still unknown. Here, we report that a LIM domain protein, cysteine-and glycine-rich protein 2 (CSRP2 [CRP2]) plays a vital role in the functional expression profile in myofibroblasts and cancer-associated fibroblasts (CAFs). Knock-down of CRP2 severely inhibits the expression of smooth muscle cell (SMC) genes, cell motility, and CAF-mediated collective invasion of epidermoid carcinoma. We elucidate the following molecular bases: CRP2 directly binds to myocardin-related transcription factors (MRTF-A/B [MRTFs]) and serum response factor (SRF) and stabilizes the MRTF/SRF/CArG-box complex to activate SMC gene expression. Furthermore, a three-dimensional structural analysis of CRP2 identifies the amino acids required for the CRP2-MRTF-A interaction. Polar amino acids in the C-terminal half (serine-152, glutamate-154, serine-155, threonine-156, threonine-157, and threonine-159 in human CRP2) are responsible for direct binding to MRTF-A. On the other hand, hydrophobic amino acids outside the consensus sequence of the LIM domain (tryptophan-139, phenylalanine-144, leucine-153, and leucine-158 in human CRP2) play a role in stabilizing the unique structure of the LIM domain.Key words: CRP2, 3D structure, myocardin-related transcription factor, myofibroblast, cancer-associated fibroblasts.

Evaluation of microaneurysms as predictors of therapeutic response to anti-VEGF therapy in patients with DME

Administration of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy is the first-line therapy for diabetic macular oedema (DME). However, some patients show no or insufficient response to repeated anti-VEGF injections. Therefore, it is necessary to identify factors that can predict this resistance against anti-VEGF treatment. Presence of microaneurysms (MAs) is a predictor of the development and progression of DME, but its relationship with the treatment response to the anti-VEGF agents is not well known. Therefore, we aimed to elucidate the relationship between the distribution of MAs and the response to anti-VEGF therapy in patients with DME. The number of MAs was measured before anti-VEGF therapy in each region using fluorescein angiography, indocyanine green angiography (IA), and optical coherence tomography angiography. Patients with DME were divided into the responder and non-responder groups after three loading phases. Differences in the distribution of MAs between the groups were investigated. Pre-treatment IA revealed more MAs in the nasal area in the non-responder group than in the responder group (10.7 ± 10.7 and 5.7 ± 5.7, respectively, in the nasal macula) (1.4 ± 2.1 and 0.4 ± 0.7, respectively, in the nasal fovea). Whereas, pre-treatment FA and OCTA could not reveal significantly difference between the groups. Detection of MAs in the nasal macula using pre-treatment IA may indicate resistance to anti-VEGF therapy. We recommend the clinicians confirm the presence of MAs in the nasal macula, as shown by IA, as a predictor of therapeutic response to anti-VEGF therapy in patients with treatment naive DME.

Evaluation of corneal hysteresis after pars plana vitrectomy combined phacoemulsification and intraocular lens implantation

We evaluated the early effects of pars plana vitrectomy (PPV) on corneal biomechanics by comparing corneal hysteresis (CH) after cataract surgery (phacoemulsification and aspiration with intraocular lens implantation; PEA + IOL) alone and PPV combined with cataract surgery. This study included 20 eyes (18 patients), who underwent cataract surgery alone (PEA + IOL group), and 28 eyes (27 patients) who underwent PPV combined with cataract surgery (PPV triple group). The CH was 11.1 ± 1.1, 10.4 ± 1.1, and 11.0 ± 1.0 mmHg in the PEA + IOL group and 11.0 ± 1.4, 9.8 ± 1.4, and 10.6 ± 1.6 mmHg in the PPV triple group, preoperatively, at 2 weeks, and 3 months after surgery, respectively. The CH was not significantly different after surgery in the PEA + IOL group, but decreased significantly in the PPV triple group 2 weeks following surgery (p < 0.01). Intraocular pressure (IOP) and central corneal thickness (CCT) did not change significantly after surgery in either group. Preoperatively, there was a positive correlation between CH and CCT in the PPV triple group, but the correlation disappeared postoperatively. In PPV combined with cataract surgery, CH temporarily decreased postoperatively, independent of IOP and CCT. Removal of the vitreous may reduce the elasticity and rigidity of the entire eye.

Simultaneous Vitreoretinal Surgery and Sclerokeratoplasty for Keratoglobus with Intraocular Hemorrhage and Extensive Corneal Rupture

We reported a case of simultaneous vitrectomy and sclerokeratoplasty (SKP) performed for keratoglobus with extensive corneal rupture and intraocular hemorrhage caused by trauma. A 73-year-old woman was treated for keratoglobus and glaucoma. She was punched in both eyes, her right eye showed corneal rupture and the left eye showed prolapse of the ocular contents due to eyeball rupture. She immediately underwent corneal sutures in the right eye and resection of the prolapsed ocular contents in the left eye at a nearby ophthalmological clinic. Three days after the injury, the patient was referred to our clinic for vision recovery. The best corrected visual acuity of the right eye was measured by counting fingers. Her right eye presented severe corneal edema with a sutured corneal wound in the upper periphery, which was positive in the Seidel test. B-mode ultrasound revealed choroidal detachment and subchoroidal hemorrhage. Fourteen days after injury, simultaneous corneal suture and posterior sclerotomy were performed in the right eye, but corneal fragility and corneal opacity were prominent, and B-mode examination revealed prolonged vitreous hemorrhage and retinal detachment. Twenty-one days after injury, we performed simultaneous SKP and 25-G pars plana vitrectomy (PPV). In this procedure, we initially performed SKP followed by 25-G PPV without a keratoprosthesis or endoscope. The visibility of the fundus through the corneoscleral graft was good during vitrectomy. Three months after surgery, her corrected visual acuity improved to 10/1,000. Although there was mild corneal stromal edema and khodadoust line, there were no obvious fundus complications. Simultaneous SKP and PPV for keratoglobus with extensive corneal rupture and vitreous diseases may be a good option.

Intravitreal Tissue Plasminogen Activator Injection for Treatment-Resistant Diabetic Macular Edema of the Vitrectomized Eye

Diabetic macular edema (DME) is the main cause of visual loss in patients with diabetic retinopathy. DME has been treated using intravitreal anti-vascular endothelial growth factor (VEGF) drugs, steroids, laser photocoagulation, vitreoretinal surgery, and their combinations. These modalities are generally effective in preserving vision, but they sometimes produce only limited responses in patients with persistent or refractory DME. The levels of various inflammatory factors, including cytokines, chemokines, and extracellular matrices, as well as VEGF in the vitreous fluid, are increased in patients with DME. Excessive fibrinogen/fibrin levels in the vitreous fluid or fibrin deposition in the retina also contribute to DME pathogenesis. Tissue plasminogen activator (t-PA) promotes the degradation of fibrinogen or fibrin. Intravitreal t-PA injection is a commonly used treatment for subretinal hemorrhage secondary to age-related macular degeneration. Intravitreal t-PA injections have previously been used to restore vision by inducing posterior vitreous detachment in patients with DME. Herein, we describe the visual outcomes of intravitreal t-PA injection in a 78-year-old woman with treatment-resistant DME in her vitrectomized eye after several previous treatments. Before the injection, her best-corrected visual acuity (BCVA) was 0.7 logMAR and central foveal retinal thickness (CRT) was 735 μm. At 1 month after the injection, her BCVA was 0.8 logMAR and CRT was 558 μm, and 3 months later, her BCVA was 0.8 logMAR and CRT was 207 μm. Her BCVA was sustained, and CRT showed gradual improvements. These findings suggested the effectiveness of intravitreal t-PA injections for DME in the vitrectomized eye.

Early manifestations and differential gene expression associated with photoreceptor degeneration in Prom1-deficient retina

Retinitis pigmentosa (RP) and macular dystrophy (MD) are characterized by gradual photoreceptor death in the retina and are often associated with genetic mutations, including those in the prominin-1 (Prom1) gene. Prom1-knockout (KO) mice recapitulate key features of these diseases including light-dependent retinal degeneration and constriction of retinal blood vessels. The mechanisms underlying such degeneration have remained unclear, however. We here analysed early events associated with retinal degeneration in Prom1-KO mice. We found that photoreceptor cell death and glial cell activation occur between 2 and 3 weeks after birth. Whereas gene expression was not affected at 2 weeks, the expression of several genes was altered at 3 weeks in the Prom1-KO retina, with the expression of that for endothelin-2 (Edn2) being markedly upregulated. Expression of Edn2 was also induced by light stimulation in Prom1-KO mice reared in the dark. Treatment with endothelin receptor antagonists attenuated photoreceptor cell death, gliosis and retinal vessel stenosis in Prom1-KO mice. Our findings thus reveal early manifestations of retinal degeneration in a model of RP/MD and suggest potential therapeutic agents for these diseases. This article has an associated First Person interview with the first author of the paper.

Cases of replacing diffractive bifocal intraocular lens with extended depth of focus intraocular lens due to waxy vision

Purpose

To investigate the postoperative course of patients who explanted a diffractive bifocal intraocular lens (IOL) due to waxy vision and implanted with an extended depth of focus IOL.

Methods

This study evaluated 29 eyes of 25 patients who underwent diffractive bifocal IOL explantation followed by TECNIS Symfony^® implantation because of dissatisfaction due to waxy vision at the Takabatake West Eye Clinic between January 2018 and November 2019. The indication criteria for this surgery were patients with uncorrected distance visual acuity of 0.05 logMAR or better, without eye diseases that may affect visual function, and no dissatisfactions about photic phenomena. We investigated patient demographics, uncorrected and corrected visual acuity, manifest refraction, contrast sensitivity, subjective symptoms, time to IOL explantation, explanted IOL type, and spectacle independence.

Results

The time to the IOL exchange after the initial IOL implantation was 55.3 ± 50.4 days (range: 14–196 days). The logMAR corrected distance visual acuity before and after IOL exchange were −0.13 ± 0.06 and −0.14 ± 0.06, respectively (p = 0.273). After IOL exchange surgery, the area under log contrast sensitivity function increased significantly from 1.07 ± 0.12 to 1.21 ± 0.12 (p < 0.001), and the waxy vision symptoms improved. The spectacle independence rate at the last visit was 88.0%.

Conclusion

For patients who complain of waxy vision despite good visual acuity after diffractive bifocal IOL implantation, exchange to extended depth of focus IOL was considered one of the useful surgical options.

Benzalkonium chloride-induced myofibroblastic transdifferentiation of Tenon's capsule fibroblasts is inhibited by coculture with corneal epithelial cells or by interleukin-10

Benzalkonium chloride (BAC) is used as a preservative in eyedrops but induces subconjunctival fibrosis that can result in failure of glaucoma surgery. Tenon's capsule fibroblasts in subconjunctival tissue interact with the corneal epithelium through tear fluid. With the use of a coculture system, we have now investigated the effect of human corneal epithelial (HCE) cells on myofibroblastic transdifferentiation of human Tenon fibroblasts (HTFs) induced by BAC (5 × 10^-6%). Immunofluorescence and immunoblot analyses revealed that the BAC-induced expression of α smooth muscle actin (αSMA) in HTFs was suppressed by coculture of these cells with HCE cells (p < 0.01). The concentration of interleukin-10 (IL-10) in culture supernatants of BAC-treated HTFs was increased by coculture with HCE cells (17.26-fold, vs. coculure, p < 0.001). Immunofluorescence and immunoblot analyses also showed that exogenous IL-10 (300 pg/ml) suppressed the BAC-induced expression of αSMA by 43.65% (p < 0.05) as well as the nuclear translocation of myocardin-related transcription factor-A (MRTF-A) by 39.32% (p < 0.01) in HTFs cultured alone. Our findings suggest that corneal epithelial cells may protect against subconjunctival fibrosis by maintaining IL-10 levels and preventing the MRTF-A-dependent transdifferentiation of HTFs into myofibroblasts.

Influence of extended depth of focus intraocular lenses on visual field sensitivity

Purpose

To investigate the influence of EDOF IOLs, TECNIS Symfony^® (Johnson & Johnson Surgical Vision, Inc.), on visual field sensitivity and to compare the IOLs with other kinds of IOLs.

Methods

The subjects included the normal fellow eyes of patients who underwent the Humphrey Field Analyzer (HFA) 30–2 with Swedish Interactive Threshold Algorithm Fast within 6 months after cataract due to glaucoma or suspected glaucoma. Each parameter of HFA was compared among eyes implanted with TENIS Symfony^® (EDOF group), diffractive bifocal IOLs (bifocal group), and monofocal IOLs (monofocal group).

Results

The total of 76 eyes, including 24 eyes in the EDOF group, 26 eyes in the bifocal group, and 26 eyes in the monofocal group, were included in this study. Mean deviation (MD) of HFA was -0.24±0.58 dB in the EDOF group, -1.38±0.58 dB in the bifocal group, and 0.02±0.44 dB in the monofocal group. Foveal threshold (FT) of HFA was 35.8±1.6 dB in the EDOF group, 33.6±1.7 dB in the bifocal group, and 36.6±1.4 dB in the monofocal group. In both MD and FT, there was significant difference between the bifocal group and the others (p<0.001). There was no difference between the EDOF group and the monofocal group. Moreover, there was no significant difference between the three groups about pattern standard deviation (PSD) of HFA.

Conclusion

TECNIS Symfony^® may have little influence on visual field sensitivity, whereas diffractive bifocal IOLs decrease visual field sensitivity.

Simultaneous Vitreoretinal Surgery and Penetrating Keratoplasty without a Keratoprosthesis or Endoscopy for Vitreoretinal Disease Associated with Corneal Opacity

We evaluated the visual outcome of combined penetrating keratoplasty (PKP) and 25G pars plana vitrectomy (PPV) performed without a temporary keratoprosthesis or endoscopy in a patient with vitreoretinal disease complicated by severe corneal opacity. The patient was a 68-year-old woman who had severe corneal opacity and silicone oil in her left eye after several previous intraocular surgeries for rhegmatogenous retinal detachment and proliferative vitreoretinopathy. We successfully performed a combined surgery of conventional PKP followed by 25G PPV without the use of a keratoprosthesis. At 6 months after surgery, visual acuity had not improved, and the density of corneal endothelial cells of the donor cornea had declined from 3,205 to 1,969 cells/mm². However, corneal transparency remained good, and additional surgery for vitreoretinal disease was not necessary. The combined surgical procedure designed to minimize the number of open-sky steps and to limit vitreoretinal complications thus proved to be safe and achieved stable corneal clarity in a patient with vitreoretinal disease and severe corneal opacity.