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Purpose: Myopia, or nearsightedness, is the most common form of refractive error and is increasing in prevalence. While significant efforts have been made to identify genetic variants that predispose individuals to myopia, these variants are believed to account for only a small portion of the myopia prevalence, leading to a feedback theory of emmetropization, which depends on the active perception of environmental visual cues. Consequently, there has been renewed interest in studying myopia in the context of light perception, beginning with the opsin family of G-protein coupled receptors (GPCRs). Refractive phenotypes have been characterized in every opsin signaling pathway studied, leaving only Opsin 3 (OPN3), the most widely expressed and blue-light sensing noncanonical opsin, to be investigated for function in the eye and refraction. Methods: Opn3 expression was assessed in various ocular tissues using an Opn3eGFP reporter. Weekly refractive development in Opn3 retinal and germline mutants from 3 to 9 weeks of age was measured using an infrared photorefractor and spectral domain optical coherence tomography (SD-OCT). Susceptibility to lens-induced myopia was then assessed using skull-mounted goggles with a -30 diopter experimental and a 0 diopter control lens. Mouse eye biometry was similarly tracked from 3 to 6 weeks. A myopia gene expression signature was assessed 24 h after lens induction for germline mutants to further assess myopia-induced changes. Results: Opn3 was found to be expressed in a subset of retinal ganglion cells and a limited number of choroidal cells. Based on an assessment of Opn3 mutants, the OPN3 germline, but not retina conditional Opn3 knockout, exhibits a refractive myopia phenotype, which manifests in decreased lens thickness, shallower aqueous compartment depth, and shorter axial length, atypical of traditional axial myopias. Despite the short axial length, Opn3 null eyes demonstrate normal axial elongation in response to myopia induction and mild changes in choroidal thinning and myopic shift, suggesting that susceptibility to lens-induced myopia is largely unchanged. Additionally, the Opn3 null retinal gene expression signature in response to induced myopia after 24 h is distinct, with opposing Ctgf, Cx43, and Egr1 polarity compared to controls. Conclusions: The data suggest that an OPN3 expression domain outside the retina can control lens shape and thus the refractive performance of the eye. Prior to this study, the role of Opn3 in the eye had not been investigated. This work adds OPN3 to the list of opsin family GPCRs that are implicated in emmetropization and myopia. Further, the work to exclude retinal OPN3 as the contributing domain in this refractive phenotype is unique and suggests a distinct mechanism when compared to other opsins.
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Miopía , Errores de Refracción , Animales , Ratones , Miopía/genética , Refracción Ocular , Retina , Opsinas/genética , Opsinas de BastonesRESUMEN
The prevalence of myopia has been steadily increasing for several decades, and this condition can cause extensive medical and economic issues in society. Exposure to violet light (VL), a short wavelength (360-400 nm) of visible light from sunlight, has been suggested as an effective preventive and suppressive treatments for the development and progression of myopia. However, the clinical application of VL remains unclear. In this study, we aimed to investigate the preventive and suppressive effects of VL on myopia progression. Various transmittances of VL (40%, 70%, and 100%) were tested in C57BL/6J mice with lens-induced myopia (LIM). Changes in the refractive error, axial length, and choroid thickness during the 3-week LIM were measured. The myopic shift in refractive error and difference in axial length between the 0 and -30 diopter lens was lessened in a transmission-dependent manner. Choroidal thinning, which was observed in myopic conditions, was suppressed by VL exposure and affected by its transmission. The results suggest that myopia progression can be managed using VL transmittance. Therefore, these factors should be considered for the prevention and treatment of myopia.
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Cristalino , Miopía , Animales , Ratones , Ratones Endogámicos C57BL , Miopía/prevención & control , Luz , Coroides , Longitud Axial del OjoRESUMEN
Myopia is increasing worldwide and its preventable measure should urgently be pursued. N-3 polyunsaturated fatty acids (PUFAs) have been reported to have various effects such as vasodilative and anti-inflammatory, which myopia may be involved in. This study is to investigate the inhibitory effect of PUFAs on myopia progression. A lens-induced myopia (LIM) model was prepared using C57B L6/J 3-week-old mice, which were equipped with a -30 diopter lens to the right eye. Chows containing two different ratios of n-3/n-6 PUFA were administered to the mice, and myopic shifts were confirmed in choroidal thickness, refraction, and axial length in the n-3 PUFA-enriched chow group after 5 weeks. To exclude the possibility that the other ingredients in the chow may have taken the suppressive effect, fat-1 transgenic mice, which can produce n-3 PUFAs endogenously, demonstrated significant suppression of myopia. To identify what elements in n-3 PUFAs took effects on myopia suppression, enucleated eyes were used for targeted lipidomic analysis, and eicosapentaenoic acid (EPA) were characteristically distributed. Administration of EPA to the LIM model confirmed the inhibitory effect on choroidal thinning and myopia progression. Subsequently, to identify the elements and the metabolites of fatty acids effective on myopia suppression, targeted lipidomic analysis was performed and it demonstrated that metabolites of EPA were involved in myopia suppression, whereas prostaglandin E2 and 14,15-dihydrotestosterone were associated with progression of myopia. In conclusion, EPA and its metabolites are related to myopia suppression and inhibition of choroidal thinning.
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Ácidos Grasos Omega-3 , Miopía , Animales , Coroides/metabolismo , Ácido Eicosapentaenoico/farmacología , Ácidos Grasos Omega-3/metabolismo , Ácidos Grasos Omega-3/farmacología , Lipidómica , Ratones , Ratones Transgénicos , Miopía/metabolismo , Miopía/prevención & controlRESUMEN
PURPOSE: Apart from genetic factors, recent animal studies on myopia have focused on localised mechanisms. In this study, we aimed to examine the contralateral effects of monocular experimental myopia and recovery, which cannot be explained by a mere local mechanism. METHODS: One eye of 3-week-old C57BL/6 male mice was fitted with a -30 dioptre (D) lens. The mice were distributed into two groups based on different conditions in the contralateral eye: either no lens (NLC) (n = 10) or a Plano lens on the contralateral eye (PLC) group (n = 6). Mice receiving no treatment on either eye were set as a control group (n = 6). Lenses were removed after 3 weeks of myopia induction. All mice were allowed to recover for 1 week in the same environment. Refractive status, axial length (AL) and choroidal thickness were measured before myopia induction, after 1 and 3 weeks of lens wear and after 1 week of recovery. RESULTS: One week after removing the lenses, complete recovery was observed in the eyes that wore the -30 D lenses. In both the PLC and NLC groups, the refractive status showed a myopic shift after lens removal. Additionally, the choroid was significantly thinned in these eyes. The -30 D wearing eye showed a significant increase in AL after 3 weeks of lens wear. While the AL of the -30 D wearing eye ceased to grow after the lens was removed, the AL in the PLC and NLC contralateral eyes increased, and the binocular ALs gradually converged. CONCLUSIONS: Recovery of lens-induced myopia was observed in mouse models. In the fellow eyes, the effects, including thinning of the choroid and changes in refractive status, were triggered by contralateral visual cues.
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Lentes de Contacto , Miopía , Animales , Masculino , Ratones , Ratones Endogámicos C57BL , Ojo , Miopía/etiología , Miopía/genética , Refracción Ocular , Coroides , Modelos Animales de EnfermedadRESUMEN
Cardiovascular abnormality-mediated retinal ischemia causes severe visual impairment. Retinal ischemia is involved in enormous pathological processes including oxidative stress, reactive gliosis, and retinal functional deficits. Thus, maintaining retinal function by modulating those pathological processes may prevent or protect against vision loss. Over the decades, nicotinamide mononucleotide (NMN), a crucial nicotinamide adenine dinucleotide (NAD+) intermediate, has been nominated as a promising therapeutic target in retinal diseases. Nonetheless, a protective effect of NMN has not been examined in cardiovascular diseases-induced retinal ischemia. In our study, we aimed to investigate its promising effect of NMN in the ischemic retina of a murine model of carotid artery occlusion. After surgical unilateral common carotid artery occlusion (UCCAO) in adult male C57BL/6 mice, NMN (500 mg/kg/day) was intraperitoneally injected to mice every day until the end of experiments. Electroretinography and biomolecular assays were utilized to measure ocular functional and further molecular alterations in the retina. We found that UCCAO-induced retinal dysfunction was suppressed, pathological gliosis was reduced, retinal NAD+ levels were preserved, and the expression of an antioxidant molecule (nuclear factor erythroid-2-related factor 2; Nrf2) was upregulated by consecutive administration of NMN. Our present outcomes first suggest a promising NMN therapy for the suppression of cardiovascular diseases-mediated retinal ischemic dysfunction.
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Arteriopatías Oclusivas , Enfermedades Cardiovasculares , Ratones , Animales , Masculino , Mononucleótido de Nicotinamida/farmacología , Mononucleótido de Nicotinamida/uso terapéutico , NAD/metabolismo , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL , Gliosis , Isquemia , Arterias Carótidas/metabolismoRESUMEN
Cardiovascular diseases lead to retinal ischemia, one of the leading causes of blindness. Retinal ischemia triggers pathological retinal glial responses and functional deficits. Therefore, maintaining retinal neuronal activities and modulating pathological gliosis may prevent loss of vision. Previously, pemafibrate, a selective peroxisome proliferator-activated receptor alpha modulator, was nominated as a promising drug in retinal ischemia. However, a protective role of pemafibrate remains untouched in cardiovascular diseases-mediated retinal ischemia. Therefore, we aimed to unravel systemic and retinal alterations by treating pemafibrate in a new murine model of retinal ischemia caused by cardiovascular diseases. Adult C57BL/6 mice were orally administered pemafibrate (0.5 mg/kg) for 4 days, followed by unilateral common carotid artery occlusion (UCCAO). After UCCAO, pemafibrate was continuously supplied to mice until the end of experiments. Retinal function (a-and b-waves and the oscillatory potentials) was measured using electroretinography on day 5 and 12 after UCCAO. Moreover, the retina, liver, and serum were subjected to qPCR, immunohistochemistry, or ELISA analysis. We found that pemafibrate enhanced liver function, elevated serum levels of fibroblast growth factor 21 (FGF21), one of the neuroprotective molecules in the eye, and protected against UCCAO-induced retinal dysfunction, observed with modulation of retinal gliosis and preservation of oscillatory potentials. Our current data suggest a promising pemafibrate therapy for the suppression of retinal dysfunction in cardiovascular diseases.
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Arteriopatías Oclusivas/complicaciones , Benzoxazoles/farmacología , Butiratos/farmacología , Arteria Carótida Común/fisiopatología , Enfermedades de la Retina/prevención & control , Animales , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BL , Enfermedades de la Retina/etiología , Enfermedades de la Retina/patologíaRESUMEN
The choroid, a vascularized tissue situated between the retina and the sclera, plays a crucial role in maintaining ocular homeostasis. Despite its significance, research on choroidal abnormalities and the establishment of effective in vitro models have been limited. In this study, we developed an in vitro choroid model through the co-culture of human induced pluripotent stem cells (hiPSC)-derived endothelial cells (ECs) and mouse choroidal fibroblasts (msCFs) with hiPSC-derived retinal pigment epithelial (RPE) cells via a permeable membrane. This model, inclusive of ECs, CFs, and RPE cells, exhibited similarities with in vivo choroidal vessels, as confirmed through immunohistochemistry of extracellular matrix markers and vascular-related markers, as well as choroid angiogenesis sprouting assay analysis. The effectiveness of our in vitro model was demonstrated in assessing vascular changes induced by drugs targeting vasoregulation. Our model offers a valuable tool for gaining insights into the pathological mechanisms underlying choroid development and the progression of choroidal vascular diseases.
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Coroides , Técnicas de Cocultivo , Células Endoteliales , Células Madre Pluripotentes Inducidas , Epitelio Pigmentado de la Retina , Coroides/irrigación sanguínea , Coroides/metabolismo , Animales , Humanos , Ratones , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Células Endoteliales/metabolismo , Epitelio Pigmentado de la Retina/metabolismo , Epitelio Pigmentado de la Retina/citología , Fibroblastos/metabolismo , Neovascularización Coroidal/metabolismo , Neovascularización Coroidal/patología , Células CultivadasRESUMEN
Photoreceptor cell death can cause progressive and irreversible visual impairments. Still, effective therapies on retinal neuroprotection are not available. Hypoxia-inducible factors (HIFs) are transcriptional factors which strongly regulate angiogenesis, erythropoiesis, intracellular metabolism, and programed cell death under a hypoxic or an abnormal metabolic oxidative stress condition. Therefore, we aimed to unravel that inhibition of HIFs could prevent disease progression in photoreceptor cell death, as recent studies showed that HIFs might be pathologic factors in retinal diseases. Adult male balb/cAJcl (8 weeks old; BALB/c) were used to investigate preventive effects of a novel HIF inhibitor halofuginone (HF) on a murine model of light-induced retinopathy. After intraperitoneal injections of phosphate-buffered saline (PBS) or HF (0.4 mg/kg in PBS) for 5 days, male BALB/c mice were subjected to a dark-adaption to being exposed to a white LED light source at an intensity of 3,000 lux for 1 hour in order to induce light-induced retinal damage. After extensive light exposure, retinal damage was evaluated using electroretinography (ERG), optical coherence tomography (OCT), and TUNEL assay. Light-induced retinal dysfunction was suppressed by HF administration. The amplitudes of scotopic a-wave and b-wave as well as that of photopic b-wave were preserved in the HF-administered retina. Outer retinal thinning after extensive light exposure was suppressed by HF administration. Based on the TUNEL assay, cell death in the outer retina was seen after light exposure. However, its cell death was not detected in the HF-administered retina. Halofuginone was found to exert preventive effects on light-induced outer retinal cell death.
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Piperidinas , Quinazolinonas , Degeneración Retiniana , Ratones , Masculino , Animales , Degeneración Retiniana/tratamiento farmacológico , Degeneración Retiniana/etiología , Degeneración Retiniana/prevención & control , Modelos Animales de Enfermedad , Retina/patología , ElectrorretinografíaRESUMEN
Myopia is a common refractive error that affects a large proportion of the population. Recent studies have revealed that alterations in choroidal thickness (ChT) and choroidal blood flow (ChBF) play important roles in the progression of myopia. Reduced ChBF could affect scleral cellular matrix remodeling, which leads to axial elongation and further myopia progression. As ChT and ChBF could be used as potential biomarkers for the progression of myopia, several recent myopia treatments have targeted alterations in ChT and ChBF. Our review provides a comprehensive overview of the recent literature review on the relationship between ChBF and myopia. We also highlight the importance of ChT and ChBF in the progression of myopia and the potential of ChT as an important biomarker for myopia progression. This summary has significant implications for the development of novel strategies for preventing and treating myopia.
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Myopia is an abnormal vision condition characterized by difficulties in seeing distant objects. Myopia has become a public health issue not only in Asian countries but also in Western countries. Previously, we found that violet light (VL, 360-400 nm wavelength) exposure effectively suppressed myopia progression in experimental chick and mice models of myopia. The inhibitory effects of VL on myopia progression are reduced in retina-specific opsin 5 (Opn5) knockout (KO) mice. Furthermore, VL exposure upregulated early growth response-1 (Egr-1) expression in the chorioretinal tissues of chicks. However, the expression of EGR-1 and role of OPN5 in mice following VL exposure remain unclear. In this study, we examined whether VL exposure-induced EGR-1 upregulation depends on Opn5 expression in the mouse retina. EGR-1 mRNA and protein expressions increased in the mouse retina and mouse retinal 661W cells following VL exposure. These increases were consistently reduced in retina specific Opn5 conditional KO mice and Opn5 KO 661W cells. Our results suggest that OPN5 mediates VL-induced EGR-1 upregulation in mice. These molecular targets could be considered for the prevention and treatment of myopia.
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Miopía , Retina , Animales , Ratones , Proteínas de la Membrana/metabolismo , Ratones Noqueados , Miopía/metabolismo , Neuronas/metabolismo , Opsinas/metabolismo , Retina/metabolismoRESUMEN
Purpose: The incidence of myopia has rapidly increased in recent decades, making it a growing public health concern worldwide. Interventions to suppress the progression of myopia are needed; one suggested strategy is the prevention of choroidal thinning, which can improve choroidal blood perfusion (ChBP). Bunazosin hydrochloride (BH) is an alpha1-adrenergic blocker and commercialized glaucoma eye drop that increases in blood circulation in the eye. In this study, we evaluated the efficacy of BH in suppressing the progression of myopia in a lens-induced murine model. Methods: Lens-induced myopia was induced in 3-week-old C57BL/6 J mice with -30 diopter (D) lenses for three weeks. Refractive error, axial length, and choroidal thickness were evaluated at three and six weeks of age using an infrared photorefractor and a spectral domain optical coherence tomography (OCT) system. Moreover, ChBP and scleral thickness were evaluated using swept-source OCT and histological analysis. Results: Compared with the controls, the administration of BH eye drops suppressed the myopic shift of refractive error (mean difference ± standard error in the eye with -30 D lens, -13.65 ± 5.69 D vs. 2.55 ± 4.30 D; P < 0.001), axial elongation (0.226 ± 0.013 mm vs. 0.183 ± 0.023 mm; P < 0.05), choroidal thinning (-2.01 ± 1.80 µm vs. 1.88 ± 1.27 µm; P < 0.001), and scleral thinning (11.41 ± 3.91 µm vs. 19.72 ± 4.01 µm; P < 0.01) with myopia progression and increased ChBP (52.0% ± 4.1% vs. 59.5% ± 6.3%; P < 0.05). The suppressive effect of BH eye drops was dose-dependent and higher than that of other glaucoma eye drops and alpha1 blockers. Conclusions: These results demonstrate the potential of BH eye drops in the treatment of myopia and support further investigation of their efficacy in humans. Further studies are needed to determine the mechanism of action and long-term safety of this treatment.
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Glaucoma , Miopía , Errores de Refracción , Humanos , Animales , Ratones , Ratones Endogámicos C57BL , Miopía/tratamiento farmacológico , Miopía/prevención & control , Soluciones Oftálmicas , PerfusiónRESUMEN
In vivo bone remodeling is promoted by the balance between osteoclast and osteoblast activity. Conventional research on bone regeneration has mainly focused on increasing osteoblast activity, with limited studies on the effects of scaffold topography on cell differentiation. Here, we examined the effect of microgroove-patterned substrate with spacings ranging from 1 to 10 µm on the differentiation of rat bone marrow-derived osteoclast precursors. Tartrate-resistant acid phosphatase (TRAP) staining and relative gene expression quantification showed that osteoclast differentiation was enhanced in substrate with 1 µm microgroove spacing compared with that in the other groups. Additionally, the ratio of podosome maturation stages in substrate with 1 µm microgroove spacing exhibited a distinct pattern, which was characterized by an increase in the ratio of belts and rings and a decrease in that of clusters. However, myosin II abolished the effects of topography on osteoclast differentiation. Overall, these showed that the reduction of myosin II tension in the podosome core by an integrin vertical vector increased podosome stability and promoted osteoclast differentiation in substrates with 1 µm microgroove spacing, including that microgroove design plays an important role in scaffolds for bone regeneration. STATEMENT OF SIGNIFICANCE: Reduction of myosin II tension in the podosome core, facilitated by an integrin vertical vector, resulted in an enhanced osteoclast differentiation, concomitant with an increase in podosome stability within 1-µm-spaced microgrooves. These findings are anticipated to serve as valuable indicators for the regulation of osteoclast differentiation through the manipulation of biomaterial surface topography in tissue engineering. Furthermore, this study contributes to the lucidation of the underlying mechanisms governing cellular differentiation by providing insights into the impact of the microtopographical environment.
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Osteoblastos , Osteoclastos , Ratas , Animales , Osteoclastos/metabolismo , Diferenciación Celular , Remodelación Ósea , Integrinas/metabolismoRESUMEN
BACKGROUND: Recent studies have indicated a strong correlation between endoplasmic reticulum (ER) stress and myopia and that eyedrops containing the ER stress inducer tunicamycin (Tm) can induce myopic changes in C57BL/6 J mice. Therefore, this study aimed to create a new myopia model using Tm eyedrops and to explore the mechanism of ER stress-mediated myopia development. METHODS: Three-week-old C57BL/6 J mice were treated with different concentrations (0, 25, 50, and 100 µg/mL) and/or number of applications (zero, one, three, and seven) of Tm eyedrops. Refraction and axial length (AL) were measured before and one week after Tm treatment. Scleral collagen alterations were evaluated under polarised light after picrosirius red staining. ER stress-related indicators, such as the expression of collagen I and cleaved collagen were detected using Western blotting. RESULTS: Compared with the control group, mice administered eyedrops with 50 µg/mL Tm only once showed the greatest myopic shifts in refraction and AL elongation and reduced scleral expression of collagen I. Picrosirius red staining showed a lower percentage of bundled collagen in the Tm group. Expression of ER-stress indicators increased in the Tm groups. Furthermore, optimised administration of Tm induced matrix metalloproteinase-2 (MMP2) expression in the sclera, which plays a major role in collagen degradation. CONCLUSIONS: We have demonstrated that ER stress in the sclera is involved in myopia progression. Tm eyedrops induced myopic changes, loosening of the scleral collagen and decreased expression of collagen I. This process may be associated with ER stress in the sclera, which upregulates the expression of MMP2 leading to collagen degradation.
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Myopia is becoming more common across the world, necessitating the development of preventive methods. We investigated the activity of early growth response 1 (EGR-1) protein and discovered that Ginkgo biloba extracts (GBEs) activated EGR-1 in vitro. In vivo, C57BL/6 J mice were fed either normal or 0.0667% GBEs (200 mg/kg) mixed chow (n = 6 each), and myopia was induced with - 30 diopter (D) lenses from 3 to 6 weeks of age. Refraction and axial length were measured by an infrared photorefractor and an SD-OCT system, respectively. In lens-induced myopia mice, oral GBEs significantly improved refractive errors (- 9.92 ± 1.53 D vs. - 1.67 ± 3.51 D, p < 0.001) and axial elongation (0.22 ± 0.02 mm vs. 0.19 ± 0.02 mm, p < 0.05). To confirm the mechanism of GBEs in preventing myopia progression, the 3-week-old mice were divided into normally fed with either myopic-induced or non-myopic-induced groups and GBEs fed with either myopic-induced or non-myopic-induced groups (n = 10 each). Choroidal blood perfusion was measured with optical coherence tomography angiography (OCTA). In both non-myopic induced groups, compared to normal chow, oral GBEs significantly improved choroidal blood perfusion (8.48 ± 15.75%Area vs. 21.74 ± 10.54%Area, p < 0.05) and expression of Egr-1 and endothelial nitric oxide synthase (eNOS) in the choroid. In both myopic-induced groups, compared to normal chow, oral GBEs also improved choroidal blood perfusion (- 9.82 ± 9.47%Area vs. 2.29 ± 11.84%Area, p < 0.05) and was positively correlated with the change in choroidal thickness. These findings suggest that GBEs may inhibit the progression of myopia by improving choroidal blood perfusion.
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Miopía , Errores de Refracción , Animales , Ratones , Ratones Endogámicos C57BL , Ginkgo biloba , Miopía/tratamiento farmacológico , AngiografíaRESUMEN
Axial length is the primary determinant of eye size, and it is elongated in myopia. However, the underlying mechanism of the onset and progression of axial elongation remain unclear. Here, we show that endoplasmic reticulum (ER) stress in sclera is an essential regulator of axial elongation in myopia development through activation of both PERK and ATF6 axis followed by scleral collagen remodeling. Mice with lens-induced myopia (LIM) showed ER stress in sclera. Pharmacological interventions for ER stress could induce or inhibit myopia progression. LIM activated all IRE1, PERK and ATF6 axis, and pharmacological inhibition of both PERK and ATF6 suppressed myopia progression, which was confirmed by knocking down above two genes via CRISPR/Cas9 system. LIM dramatically changed the expression of scleral collagen genes responsible for ER stress. Furthermore, collagen fiber thinning and expression of dysregulated collagens in LIM were ameliorated by 4-PBA administration. We demonstrate that scleral ER stress and PERK/ATF6 pathway controls axial elongation during the myopia development in vivo model and 4-PBA eye drop is promising drug for myopia suppression/treatment.
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Factor de Transcripción Activador 6 , Miopía , Esclerótica , eIF-2 Quinasa , Factor de Transcripción Activador 6/genética , Factor de Transcripción Activador 6/metabolismo , Animales , Butilaminas , Modelos Animales de Enfermedad , Estrés del Retículo Endoplásmico , Ratones , Miopía/genética , Miopía/metabolismo , Soluciones Oftálmicas/metabolismo , Soluciones Oftálmicas/uso terapéutico , Proteínas Serina-Treonina Quinasas , Esclerótica/metabolismo , eIF-2 Quinasa/genética , eIF-2 Quinasa/metabolismoRESUMEN
Myopia, which prevalence is rapidly increasing, causes visual impairment; however, the onset mechanism of pathological axial length (AL) elongation remains unclear. A highly vascularized choroid between the retinal pigment epithelium (RPE) and sclera not only maintains physiological activities, but also contributes to ocular development and growth regulation. Vascular endothelial growth factor (VEGF) secreted from the RPE to the choroid is essential for retinal function and maintenance of the choriocapillaris. Herein, we demonstrated that the loss of VEGF secreted from the RPE caused abnormal choriocapillaris development and AL elongation, with features similar to those of the lens-induced myopia (LIM) mouse model, whereas VEGF overexpression by knocking-out von Hippel-Lindau (VHL) specific to the RPE expands the choriocapillaris and shortens the AL. Additionally, LDL Receptor Related Protein 2 (LRP2) deletion in the RPE downregulated VEGF expression and leads to pathological AL elongation. Furthermore, high-myopia patients without choriocapillaris demonstrated longer ALs than did those with preserved choriocapillaris. These results suggest that physiological secretion of VEGF from the RPE is required for proper AL development by maintaining the choriocapillaris. The pinpoint application of VEGF to the choriocapillaris may become a potential intervention for the prevention and treatment of axial myopia progression.
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Ocular ischemia is a common cause of blindness and plays a detrimental role in various diseases such as diabetic retinopathy, occlusion of central retinal arteries, and ocular ischemic syndrome. Abnormalities of neuronal activities in the eye occur under ocular ischemic conditions. Therefore, protecting their activities may prevent vision loss. Previously, peroxisome proliferator-activated receptor alpha (PPARα) agonists were suggested as promising drugs in ocular ischemia. However, the potential therapeutic roles of PPARα agonists in ocular ischemia are still unknown. Thus, we attempted to unravel systemic and ocular changes by treatment of fenofibrate, a well-known PPARα agonist, in a new murine model of ocular ischemia. Adult mice were orally administered fenofibrate (60 mg/kg) for 4 days once a day, followed by induction of ocular ischemia by unilateral common carotid artery occlusion (UCCAO). After UCCAO, fenofibrate was continuously supplied to mice once every 2 days during the experiment period. Electroretinography was performed to measure retinal functional changes. Furthermore, samples from the retina, liver, and blood were subjected to qPCR, Western blot, or ELISA analysis. We found that fenofibrate boosted liver function, increased serum levels of fibroblast growth factor 21 (FGF21), one of the neuroprotective molecules in the central nervous system, and protected against UCCAO-induced retinal dysfunction. Our current data suggest a promising fenofibrate therapy in ischemic retinopathies.
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BACKGROUND: Retinal ischemic stresses are associated with the pathogenesis of various retinal vascular diseases. To investigate pathological mechanisms of retinal ischemia, reproducible, robust and clinically significant experimental rodent models are highly needed. Previously, we established a stable murine model of chronic hypoperfusion retinal injuries by permanent unilateral common carotid artery occlusion (UCCAO) and demonstrated chronic pathological processes in the ischemic retina after the occlusion; however, retinal functional deficits and other acute retinal ischemic injuries by UCCAO still remain obscure. In this study, we attempted to examine retinal functional changes as well as acute retinal ischemic alterations such as retinal thinning, gliosis and cell death after UCCAO. METHODS: Adult mice (male C57BL/6, 6-8 weeks old) were subjected to UCCAO in the right side, and retinal function was primarily measured using electroretinography for 14 days after the surgery. Furthermore, retinal thinning, gliosis and cell death were investigated using optical coherence tomography, immunohistochemistry and TUNEL assay, respectively. RESULTS: Functional deficits in the unilateral right retina started to be seen 7 days after the occlusion. Specifically, the amplitude of b-wave dramatically decreased while that of a-wave was slightly affected. 14 days after the occlusion, the amplitudes of both waves and oscillatory potentials were significantly detected decreased in the unilateral right retina. Even though a change in retinal thickness was not dramatically observed among all the eyes, retinal gliosis and cell death in the unilateral right retina were substantially observed after UCCAO. CONCLUSIONS: Along with previous retinal ischemic results in this model, UCCAO can stimulate retinal ischemia leading to functional, morphological and molecular changes in the retina. This model can be useful for the investigation of pathological mechanisms for human ischemic retinopathies and furthermore can be utilized to test new drugs for various ischemic ocular diseases.
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Diverse vascular diseases such as diabetic retinopathy, occlusion of retinal veins or arteries and ocular ischemic syndrome can lead to retinal ischemia. To investigate pathological mechanisms of retinal ischemia, relevant experimental models need to be developed. Anatomically, a main retinal blood supplying vessel is the ophthalmic artery (OpA) and OpA originates from the internal carotid artery of the common carotid artery (CCA). Thus, disruption of CCA could effectively cause retinal ischemia. Here, we established a mouse model of retinal ischemia by transient bilateral common carotid artery occlusion (tBCCAO) to tie the right CCA with 6-0 silk sutures and to occlude the left CCA transiently for 2 seconds via a clamp, and showed that tBCCAO could induce acute retinal ischemia leading to retinal dysfunction. The current method reduces reliance on surgical instruments by only using surgical needles and a clamp, shortens occlusion time to minimize unexpected animal death, which is often seen in mouse models of middle cerebral artery occlusion, and maintains reproducibility of common retinal ischemic findings. The model can be utilized to investigate the pathophysiology of ischemic retinopathies in mice and further can be used for in vivo drug screening.
Asunto(s)
Arteriopatías Oclusivas/complicaciones , Arteria Carótida Común/patología , Isquemia/etiología , Retina/lesiones , Animales , Arteriopatías Oclusivas/diagnóstico por imagen , Arteriopatías Oclusivas/fisiopatología , Círculo Arterial Cerebral/patología , Modelos Animales de Enfermedad , Electrorretinografía , Gliosis/complicaciones , Gliosis/diagnóstico por imagen , Gliosis/patología , Gliosis/fisiopatología , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Isquemia/diagnóstico por imagen , Isquemia/patología , Isquemia/fisiopatología , Masculino , Ratones , Perfusión , Estabilidad Proteica , Reproducibilidad de los Resultados , Retina/diagnóstico por imagen , Retina/patología , Retina/fisiopatología , Tomografía de Coherencia ÓpticaRESUMEN
Neovascular retinal degeneration is a leading cause of blindness in advanced countries. Anti-vascular endothelial growth factor (VEGF) drugs have been used for neovascular retinal diseases; however, anti-VEGF drugs may cause the development of chorioretinal atrophy in chronic therapy as they affect the physiological amount of VEGF needed for retinal homeostasis. Hypoxia-inducible factor (HIF) is a transcription factor inducing VEGF expression under hypoxic and other stress conditions. Previously, we demonstrated that HIF was involved with pathological retinal angiogenesis in murine models of oxygen-induced retinopathy (OIR), and pharmacological HIF inhibition prevented retinal neovascularization by reducing an ectopic amount of VEGF. Along with this, we attempted to find novel effective HIF inhibitors. Compounds originally isolated from mushroom-forming fungi were screened for prospective HIF inhibitors utilizing cell lines of 3T3, ARPE-19 and 661W. A murine OIR model was used to examine the anti-angiogenic effects of the compounds. As a result, 2-azahypoxanthine (AHX) showed an inhibitory effect on HIF activation and suppressed Vegf mRNA upregulation under CoCl2-induced pseudo-hypoxic conditions. Oral administration of AHX significantly suppressed retinal neovascular tufts in the OIR model. These data suggest that AHX could be a promising anti-angiogenic agent in retinal neovascularization by inhibiting HIF activation.