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1.
Proc Natl Acad Sci U S A ; 121(19): e2318438121, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38696464

RESUMO

Alternative lengthening of telomeres (ALT) is a telomere maintenance mechanism mediated by break-induced replication, evident in approximately 15% of human cancers. A characteristic feature of ALT cancers is the presence of C-circles, circular single-stranded telomeric DNAs composed of C-rich sequences. Despite the fact that extrachromosomal C-rich single-stranded DNAs (ssDNAs), including C-circles, are unique to ALT cells, their generation process remains undefined. Here, we introduce a method to detect single-stranded telomeric DNA, called 4SET (Strand-Specific Southern-blot for Single-stranded Extrachromosomal Telomeres) assay. Utilizing 4SET, we are able to capture C-rich single-stranded DNAs that are near 200 to 1500 nucleotides in size. Both linear C-rich ssDNAs and C-circles are abundant in the fractions of cytoplasm and nucleoplasm, which supports the idea that linear and circular C-rich ssDNAs are generated concurrently. We also found that C-rich ssDNAs originate during Okazaki fragment processing during lagging strand DNA synthesis. The generation of C-rich ssDNA requires CST-PP (CTC1/STN1/TEN1-PRIMASE-Polymerase alpha) complex-mediated priming of the C-strand DNA synthesis and subsequent excessive strand displacement of the C-rich strand mediated by the DNA Polymerase delta and the BLM helicase. Our work proposes a model for the generation of C-rich ssDNAs and C-circles during ALT-mediated telomere elongation.


Assuntos
DNA de Cadeia Simples , Homeostase do Telômero , Telômero , Telômero/genética , Telômero/metabolismo , Humanos , DNA de Cadeia Simples/metabolismo , DNA de Cadeia Simples/genética , Replicação do DNA , DNA/genética , DNA/metabolismo , DNA Circular/genética , DNA Circular/metabolismo , Southern Blotting , DNA Polimerase III/metabolismo , DNA Polimerase III/genética
2.
Nano Lett ; 24(6): 1882-1890, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38198287

RESUMO

Understanding the spatial organization of membrane proteins is crucial for unraveling key principles in cell biology. The reaction-diffusion model is commonly used to understand biochemical patterning; however, applying reaction-diffusion models to subcellular phenomena is challenging because of the difficulty in measuring protein diffusivity and interaction kinetics in the living cell. In this work, we investigated the self-organization of the plasmalemma vesicle-associated protein (PLVAP), which creates regular arrangements of fenestrated ultrastructures, using single-molecule tracking. We demonstrated that the spatial organization of the ultrastructures is associated with a decrease in the association rate by actin destabilization. We also constructed a reaction-diffusion model that accurately generates a hexagonal array with the same 130 nm spacing as the actual scale and informs the stoichiometry of the ultrastructure, which can be discerned only through electron microscopy. Through this study, we integrated single-molecule experiments and reaction-diffusion modeling to surpass the limitations of static imaging tools and proposed emergent properties of the PLVAP ultrastructure.


Assuntos
Proteínas de Transporte , Proteínas de Membrana , Proteínas de Membrana/metabolismo , Difusão , Modelos Biológicos
3.
BMC Ophthalmol ; 24(1): 199, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38671442

RESUMO

BACKGROUND: Although choroidal thickening was reported as a sign of active inflammation in ocular sarcoidosis, there has been no research on the choroidal changes in non-ocular sarcoidosis (defined as systemic sarcoidosis without overt clinical signs of ocular involvement). Therefore, this study aimed to investigate choroidal structural changes in patients with non-ocular sarcoidosis. METHODS: This retrospective case-control study was conducted at Asan Medical Center, a tertiary referral center. We evaluated 30 eyes with non-ocular sarcoidosis and their age- and spherical equivalent-matched healthy control eyes. The subfoveal choroidal thickness, area ratio (Sattler layer-choriocapillaris complex [SLCC] area to Haller layer [HL] area), and choroidal vascularity index (CVI, luminal area to choroidal area) were analyzed using enhanced depth imaging in optical coherence tomography. Systemic and ocular factors associated with the choroidal thickness were investigated. RESULTS: Compared with the healthy control group, the non-ocular sarcoidosis group had significantly thicker subfoveal choroid (total and all sublayers [SLCC and HL]) and lower area ratio. There were no significant differences in the CVIs at all sublayers between groups. In the non-ocular sarcoidosis group, eyes under oral steroid treatment had thinner choroid than eyes under observation. In the control group, eyes with older age and more myopic spherical equivalent had thinner choroidal thickness. CONCLUSION: Total and all sublayers of the subfoveal choroid were significantly thicker without significant vascularity changes in non-ocular sarcoidosis eyes than in healthy control eyes. The degree of choroidal thickening was disproportionally greater at HL than at SLCC. These characteristic choroidal changes may be the subclinical manifestations in non-ocular sarcoidosis.


Assuntos
Doenças da Coroide , Corioide , Sarcoidose , Tomografia de Coerência Óptica , Humanos , Tomografia de Coerência Óptica/métodos , Estudos Retrospectivos , Masculino , Feminino , Sarcoidose/diagnóstico , Sarcoidose/complicações , Sarcoidose/diagnóstico por imagem , Pessoa de Meia-Idade , Corioide/patologia , Corioide/diagnóstico por imagem , Corioide/irrigação sanguínea , Estudos de Casos e Controles , Doenças da Coroide/diagnóstico , Doenças da Coroide/etiologia , Doenças da Coroide/diagnóstico por imagem , Adulto , Idoso , Acuidade Visual
4.
Semin Cell Dev Biol ; 113: 88-96, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33293233

RESUMO

Overcoming cellular senescence that is induced by telomere shortening is critical in tumorigenesis. A majority of cancers achieve telomere maintenance through telomerase expression. However, a subset of cancers takes an alternate route for elongating telomeres: recombination-based alternative lengthening of telomeres (ALT). Current evidence suggests that break-induced replication (BIR), independent of RAD51, underlies ALT telomere synthesis. However, RAD51-dependent homologous recombination is required for homology search and inter-chromosomal telomere recombination in human ALT cancer cell maintenance. Accumulating evidence suggests that the breakdown of stalled replication forks, the replication stress, induces BIR at telomeres. Nevertheless, ALT research is still in its early stage and a comprehensive view is still unclear. Here, we review the current findings regarding the genesis of ALT, how this recombinant pathway is chosen, the epigenetic regulation of telomeres in ALT, and perspectives for clinical applications with the hope that this overview will generate new questions.


Assuntos
Senescência Celular/genética , Recombinação Genética/genética , Homeostase do Telômero/genética , Humanos
5.
Diabetes Metab Res Rev ; 39(7): e3681, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37382083

RESUMO

AIMS: The association between skeletal muscle mass and diabetes incidence/insulin resistance/glycated hemoglobin (HbA1C) is unknown. The aim of this study was to investigate such association in clinically apparently healthy males and females. METHODS: A cross-sectional study of 372,399 Korean males and females who completed bioelectrical impedance analysis (BIA) in a health-screening programme was performed. Skeletal muscle index was used as an indicator of skeletal muscle mass. Skeletal muscle index (%) [appendicular skeletal muscle mass (kg)/body weight (kg)X100] was estimated using BIA. The study outcomes were diabetes incidence, homoeostasis model assessment of insulin resistance (HOMA-IR), and HbA1C. RESULTS: The mean age of study participants was 38.92 ± 8.54 years. Multiple logistic regression analysis revealed a significant negative association between Skeletal muscle index and diabetes incidence/HOMA-IR/HbA1C after adjusting for various confounding factors. Odds ratios (95% confidence interval (CI)) of diabetes incidence in Q2, Q3, and Q4 compared to the lowest quantile (Q1) were 0.95 (0.85-1.05), 0.88 (0.78-0.99), and 0.79 (0.69-0.9), respectively. Beta coefficients (95% CI) of HOMA-IR in Q2, Q3, and Q3 with Q1 were 0.05 (0.03-0.07), -0.06 (-0.09∼-0.04), and -0.19 (-0.22∼-0.16), respectively. Beta coefficients (95% CI) of HbA1C in Q2, Q3, and Q4 with Q1 were 0.02 (0.01-0.03), -0.001 (-0.01∼0.01), and -0.02 (-0.03∼-0.01), respectively. CONCLUSIONS: This study demonstrated negative associations of skeletal muscle mass with diabetes incidence, insulin resistance, and HbA1C levels in healthy adults.

6.
J Nanobiotechnology ; 21(1): 242, 2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37507708

RESUMO

BACKGROUND: Central serous chorioretinopathy (CSC) is the fourth most prevalent retinal disease leading to age-related macular degeneration (AMD) and retinal atrophy. However, CSC's pathogenesis and therapeutic target need to be better understood. RESULTS: We investigated exosomal microRNA in the aqueous humor of CSC patients using next-generation sequencing (NGS) to identify potential biomarkers associated with CSC pathogenesis. Bioinformatic evaluations and NGS were performed on exosomal miRNAs obtained from AH samples of 62 eyes (42 CSC and 20 controls). For subgroup analysis, patients were divided into treatment responders (CSC-R, 17 eyes) and non-responders (CSC-NR, 25 eyes). To validate the functions of miRNA in CECs, primary cultured-human choroidal endothelial cells (hCEC) of the donor eyes were utilized for in vitro assays. NGS detected 376 miRNAs. Our results showed that patients with CSC had 12 significantly upregulated and 17 downregulated miRNAs compared to controls. miR-184 was significantly upregulated in CSC-R and CSC-NR patients compared to controls and higher in CSC-NR than CSC-R. In vitro assays using primary cultured-human choroidal endothelial cells (hCEC) demonstrated that miR-184 suppressed the proliferation and migration of hCECs. STC2 was identified as a strong candidate for the posttranscriptional down-regulated target gene of miR-184. CONCLUSION: Our findings suggest that exosomal miR-184 may serve as a biomarker reflecting the angiostatic capacity of CEC in patients with CSC.


Assuntos
Coriorretinopatia Serosa Central , MicroRNAs , Humanos , Humor Aquoso , Biomarcadores , Coriorretinopatia Serosa Central/diagnóstico , Coriorretinopatia Serosa Central/genética , Coriorretinopatia Serosa Central/tratamento farmacológico , Células Endoteliais , Angiofluoresceinografia/métodos , MicroRNAs/genética , MicroRNAs/uso terapêutico , Prognóstico
7.
BMC Ophthalmol ; 23(1): 34, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36698088

RESUMO

BACKGROUND: To identify factors associated with microvascular recovery after intravitreal bevacizumab or panretinal photocoagulation (PRP) in diabetic retinopathy (DR). METHODS: We retrospectively reviewed 320 eyes/patients with DR treated with intravitreal bevacizumab and/or PRP. Two consecutive fluorescein angiographies (FAs) of each eye were compared. The number of microaneurysms and the area of capillary non-perfusion were calculated automatically using ImageJ software. Microvascular recovery was defined as a marked reduction in the numbers of microaneurysms (< 20%) or a marked reduction in the area of capillary non-perfusion (< 50%) in 45-degree fields or a complete regression of new vessels in ETDRS 7 standard fields. Baseline FA findings and changes in the ocular and systemic factors were analyzed. RESULTS: Twenty-eight (8.8%) of the 320 total eyes were found to meet the criteria of microvascular recovery after the treatments. Multivariate analysis revealed the presence of diffuse capillary telangiectasis (P = .003) and late disc leaking (P = .007) on baseline FA and a reduction of glycated hemoglobin (P = .005) during the follow-up period were predictive factors of microvascular recovery after the treatments. Although the microvascular recovery group presented with a significant improvement of BCVA after the treatments, the baseline BCVA could not predict the microvascular recovery after the treatments. CONCLUSIONS: Diffuse capillary telangiectasis or late disc leaking on baseline FA and improved glycemic control positively predicted the microvascular recovery after treatments for DR.


Assuntos
Diabetes Mellitus , Retinopatia Diabética , Microaneurisma , Humanos , Bevacizumab/uso terapêutico , Retinopatia Diabética/cirurgia , Retinopatia Diabética/tratamento farmacológico , Inibidores da Angiogênese/uso terapêutico , Estudos Retrospectivos , Fotocoagulação a Laser , Angiofluoresceinografia , Injeções Intravítreas , Tomografia de Coerência Óptica
8.
Sensors (Basel) ; 24(1)2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38202920

RESUMO

Weakly supervised video anomaly detection is a methodology that assesses anomaly levels in individual frames based on labeled video data. Anomaly scores are computed by evaluating the deviation of distances derived from frames in an unbiased state. Weakly supervised video anomaly detection encounters the formidable challenge of false alarms, stemming from various sources, with a major contributor being the inadequate reflection of frame labels during the learning process. Multiple instance learning has been a pivotal solution to this issue in previous studies, necessitating the identification of discernible features between abnormal and normal segments. Simultaneously, it is imperative to identify shared biases within the feature space and cultivate a representative model. In this study, we introduce a novel multiple instance learning framework anchored on a memory unit, which augments features based on memory and effectively bridges the gap between normal and abnormal instances. This augmentation is facilitated through the integration of an multi-head attention feature augmentation module and loss function with a KL divergence and a Gaussian distribution estimation-based approach. The method identifies distinguishable features and secures the inter-instance distance, thus fortifying the distance metrics between abnormal and normal instances approximated by distribution. The contribution of this research involves proposing a novel framework based on MIL for performing WSVAD and presenting an efficient integration strategy during the augmentation process. Extensive experiments were conducted on benchmark datasets XD-Violence and UCF-Crime to substantiate the effectiveness of the proposed model.

9.
J Am Chem Soc ; 144(21): 9217-9221, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35588478

RESUMO

The ternary neptunium(V) (Np(V)) hydroxides Na0.5[NpO2(OH)1.5]·0.5H2O (I) and Na[NpO2(OH)2] (II) were synthesized in aqueous NaOH solutions at T = 80 °C, and their crystal structures were determined to be monoclinic, P21, Z = 2, a = 5.9859(2), b = 10.1932(3), c = 12.1524(4) Å, ß = 98.864(1)°, V = 732.63(4) Å3 for (I) and orthorhombic, P212121, Z = 4, a = 5.856(7), b = 7.621(9), c = 8.174(9) Å, V = 364.8(7) Å3 for (II). By combining the detailed structural information with results from systematic solubility investigations, a comprehensive chemical and thermodynamic model of the Np(V) behavior in NaCl-NaOH solutions was evaluated. The results reveal a great stability of the ternary Na-Np(V)-OH solid phases that significantly enhances the predominance field of the entire Np(V) redox state to high alkalinity.

10.
Circ Res ; 126(6): 767-783, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32078435

RESUMO

RATIONALE: Central nervous system has low vascular permeability by organizing tight junction (TJ) and limiting endothelial transcytosis. While TJ has long been considered to be responsible for vascular barrier in central nervous system, suppressed transcytosis in endothelial cells is now emerging as a complementary mechanism. Whether transcytosis regulation is independent of TJ and its dysregulation dominantly causes diseases associated with edema remain elusive. Dll4 signaling is important for various vascular contexts, but its role in the maintenance of vascular barrier in central nervous system remains unknown. OBJECTIVE: To find a TJ-independent regulatory mechanism selective for transcytosis and identify its dysregulation as a cause of pathological leakage. METHODS AND RESULTS: We studied transcytosis in the adult mouse retina with low vascular permeability and employed a hypertension-induced retinal edema model for its pathological implication. Both antibody-based and genetic inactivation of Dll4 or Notch1 induce hyperpermeability by increasing transcytosis without junctional destabilization in arterial endothelial cells, leading to nonhemorrhagic leakage predominantly in the superficial retinal layer. Endothelial Sox17 deletion represses Dll4 in retinal arteries, phenocopying Dll4 blocking-driven vascular leakage. Ang II (angiotensin II)-induced hypertension represses arterial Sox17 and Dll4, followed by transcytosis-driven retinal edema, which is rescued by a gain of Notch activity. Transcriptomic profiling of retinal endothelial cells suggests that Dll4 blocking activates SREBP1 (sterol regulatory element-binding protein 1)-mediated lipogenic transcription and enriches gene sets favorable for caveolae formation. Profiling also predicts the activation of VEGF (vascular endothelial growth factor) signaling by Dll4 blockade. Inhibition of SREBP1 or VEGF-VEGFR2 (VEGF receptor 2) signaling attenuates both Dll4 blockade-driven and hypertension-induced retinal leakage. CONCLUSIONS: In the retina, Sox17-Dll4-SREBP1 signaling axis controls transcytosis independently of TJ in superficial arteries among heterogeneous regulations for the whole vessels. Uncontrolled transcytosis via dysregulated Dll4 underlies pathological leakage in hypertensive retina and could be a therapeutic target for treating hypertension-associated retinal edema.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Barreira Hematorretiniana/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Retinopatia Hipertensiva/metabolismo , Transcitose , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Artérias/metabolismo , Proteínas de Ligação ao Cálcio/genética , Cavéolas/metabolismo , Células Endoteliais/metabolismo , Proteínas HMGB/metabolismo , Homeostase , Camundongos , Camundongos Endogâmicos C57BL , Receptor Notch1/genética , Receptor Notch1/metabolismo , Fatores de Transcrição SOXF/metabolismo , Transdução de Sinais , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Junções Íntimas/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
11.
Retina ; 42(10): 1939-1949, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-36129267

RESUMO

PURPOSE: The study aimed to evaluate the macular microvasculature of X-linked retinoschisis (XLRS) and identify correlations between vascular changes, structural changes, and functional outcome. METHODS: Genetically confirmed XLRS patients and heathy control subjects underwent complete ophthalmic examination, dilated funduscopic examination, optical coherence tomography, and optical coherence tomography angiography. Schisis distribution, outer plexiform layer discontinuation, photoreceptor layer thickness, and photoreceptor outer segment length were reviewed using optical coherence tomography. Vascular flow density and foveal thickness at foveal and parafoveal area were measured using optical coherence tomography angiography. RESULTS: A total of 17 eyes of 9 XLRS patients and 22 eyes of 11 control subjects were examined from July 2018 to August 2020. Flow density in the deep capillary plexus at foveal and parafoveal area decreased in XLRS patients compared with control subjects (P = 0.014 and 0.001, respectively), whereas foveal avascular zone area and perimeter remarkably increased (P = 0.015 and 0.001, respectively). Although outer and total retinal layers were significantly thicker in XLRS, inner retinal layer was thinner with reduced photoreceptor layer thickness and shortened photoreceptor outer segment length (P < 0.001 and P < 0.001, respectively). Foveal flow loss in deep capillary plexus, foveal avascular zone enlargement, thinner inner retina and photoreceptor layer thickness, and shortened photoreceptor outer segment length correlated with best-corrected visual acuity. CONCLUSION: X-linked retinoschisis eyes exhibit decreased flow density in the deep capillary plexus and variable foveal avascular zone with enlarged perimeter. Structural deterioration of the photoreceptor best reflects the degenerative changes, whereas microvascular alteration shows considerable correlation with functional outcome in XLRS.


Assuntos
Retinosquise , Angiofluoresceinografia/métodos , Fóvea Central , Humanos , Microvasos , Vasos Retinianos/diagnóstico por imagem , Retinosquise/diagnóstico por imagem , Retinosquise/genética , Estudos Retrospectivos , Tomografia de Coerência Óptica/métodos , Acuidade Visual
12.
BMC Ophthalmol ; 21(1): 453, 2021 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-34961529

RESUMO

BACKGROUND: To report a rare case of granular cell tumor invading the retina. CASE PRESENTATION: A 56-year-old female complained of blurred vision for 2 weeks in her left eye. An irregular-shaped retinal mass in the inferonasal and extending to the optic disc accompanied by dense exudation and extensive serous retinal detachment was observed. Several intravitreal bevacizumab injections were ineffective for stabilizing retinal exudation and intraocular pressure (IOP). Vitrectomy was performed to re-attach the retina and obtain a tumor biopsy specimen. Histopathological analysis revealed that the intraocular mass was a granular cell tumor. Immunohistochemical studies demonstrated that the tumor was positive for S100 and CD68, focal positive for neurofilaments, but negative for ERG and HMB-45. Local recurrence and distant metastasis were not found, but visual acuity had worsened to no light perception at the last visit due to uncontrolled intraocular pressure and retinal exudation after the surgery. CONCLUSIONS: Granular cell tumor is a rare benign neoplasm, but it can lead to devastating visual loss if it invades the retina adjacent to the optic nerve head.


Assuntos
Tumor de Células Granulares , Neoplasias da Retina , Feminino , Tumor de Células Granulares/diagnóstico , Tumor de Células Granulares/cirurgia , Humanos , Pessoa de Meia-Idade , Retina , Transtornos da Visão , Vitrectomia
13.
Biochem Biophys Res Commun ; 521(4): 939-946, 2020 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-31718797

RESUMO

Crumbs proteins are transmembrane proteins that regulate cellular apico-basal polarity. Animals carrying mutated crb1 present retinal vascular abnormalities; this mutation is associated with progressive retinal degeneration with intraretinal cystoid fluid collection in humans. This study aimed to evaluate a potential role of crumbs proteins in retinal vascular development and maintenance. We demonstrated that crumbs homologues (CRBs) were differentially expressed and changed dramatically during mouse retinal vascular development. Intravitreal injection of CRB1 and CRB2 siRNA induced delayed development of the deep capillary plexus and premature development of the intermediate capillary plexus, resulting in disrupted vascular integrity. However, microfluidic chip assay using human retinal endothelial cells revealed that CRBs do not directly affect in vitro retinal angiogenesis. CRBs control retinal angiogenesis by regulating neuroglial vascular endothelial growth factor-A (VEGFA) and matrix metalloproteinase-3 expression. These findings demonstrate a pivotal role of CRBs in providing critical neurotrophic support through normal layered vascular network development and maintenance. This implies that preserving CRBs and restoring layered retinal vascular networks could be novel targets for preventing vision-threatening retinal diseases.


Assuntos
Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Vasos Retinianos/crescimento & desenvolvimento , Animais , Animais Recém-Nascidos , Células Cultivadas , Eletrorretinografia , Células Endoteliais , Proteínas do Olho/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Metaloproteinase 3 da Matriz/metabolismo , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Neovascularização Fisiológica/genética , Proteínas do Tecido Nervoso/genética , Retina/citologia , Retina/efeitos dos fármacos , Retina/patologia , Vasos Retinianos/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/farmacologia
14.
Biochem Biophys Res Commun ; 522(1): 240-246, 2020 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-31759628

RESUMO

Fenestrations in choriocapillaris act as a window for molecular transports between the retina and choroid, and is crucial for maintaining visual function. Plasmalemma vesicle-associated protein (PLVAP) is essential for the development of endothelial fenestrations. There is little knowledge about how the choriocapillaris maintains the fenestrated endothelium. This study aimed to evaluate the role of vascular endothelial growth factor-A (VEGFA)-PLVAP axis in the maintenance of choroidal fenestrations using oxygen-induced retinopathy (OIR) model. In C57BL/6 J mice, the mice with OIR on postnatal day 12 (P12) presented thicker endothelium and less fenestration compared to the non-OIR mice. However, the OIR on 17 mice showed thinner endothelium with more fenestration compared to OIR on P12. In vivo angiography demonstrated the presence of hyperpermeable choroidal vessels on P17 in OIR mice. These dramatic changes in choriocapillaris were not observed in the BALB/cJ OIR model. The ultrastructural changes in the choriocapillaris were correlated with temporal variations in the expression of VEGFA and PLVAP. VEGFA stimulated expression of PLVAP in the choroidal endothelial cells. Loss of PLVAP disrupts the polarized structure of the choriocapillaris leading to retinal degeneration. These results indicate that the expression of retinal VEGFA is essential for maintaining the structure and function of choriocapillaris by preserving the endothelial PLVAP.


Assuntos
Corioide/metabolismo , Proteínas de Membrana/metabolismo , Retina/metabolismo , Doenças Retinianas/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Células Cultivadas , Corioide/patologia , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Humanos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Oxigênio/metabolismo , Retina/patologia , Doenças Retinianas/patologia
15.
Int J Mol Sci ; 21(6)2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32245120

RESUMO

Structural alterations of pericytes in microvessels are important features of diabetic retinopathy. Although capillary pericytes had been known not to have α-smooth muscle actin (αSMA), a recent study revealed that a specific fixation method enabled the visualization of αSMA along retinal capillaries. In this study, we applied snap-fixation in wild type and streptozotocin-induced diabetic mice to evaluate the differences in vascular smooth muscle cells of the retina and the choroid. Mice eyeballs were fixed in ice-cold methanol to prevent the depolymerization of filamentous actin. Snap-fixated retina showed αSMA expression in higher-order branches along the capillaries as well as the arterioles and venules, which were not detected by paraformaldehyde fixation. In contrast, most choriocapillaris, except those close to the arterioles, were not covered with αSMA-positive perivascular mural cells. Large choroidal vessels were covered with more αSMA-positive cells in the snap-fixated eyes. Diabetes induced less coverage of αSMA-positive perivascular mural cells overall, but they reached higher-order branches of the retinal capillaries, which was prominent in the aged mice. More αSMA-positive pericytes were observed in the choroid of diabetic mice, but the αSMA-positive expression reduced with aging. This study suggests the potential role of smooth muscle cells in the pathogenesis of age-related diabetic retinopathy and choroidopathy.


Assuntos
Actinas/metabolismo , Corioide/irrigação sanguínea , Corioide/citologia , Retina/citologia , Animais , Capilares/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Fixação de Tecidos
16.
Biochem Biophys Res Commun ; 516(2): 350-356, 2019 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-31208720

RESUMO

Receptor activator of NF-κB ligand (RANKL) is a member of the TNF superfamily. RANKL increases endothelial permeability and induces angiogenesis, suggesting its critical roles in the vasculature. Despite the evidence implicating RANKL in vascular pathology, its role in ischemic retinopathy has not been previously reported. In this study, neonatal mice were exposed to 75% oxygen from postnatal day (P)7 to P12 to induce vaso-obliteration, and then returned to room air from P12 to P17, causing the retina to become hypoxic and inducing vascular endothelial growth factor (VEGF) signaling, which produces pathological neovascularization. On P12, the mice received a single intravitreal injection of control IgG1 or RANK-Fc, and retinas were obtained at P17. On P17, RANKL was expressed strongly and selectively in the neovascular tufts (NVT) area. RANKL colocalized with αSMA or PDGFRß in NVT. However, co-immunostaining revealed that CD31-positive areas were not the same as RANKL, which indicates that RANKL might be produced by retinal pericytes, not endothelial cells. Consistent with this finding, chemical hypoxia upregulated RANKL expression in cultured human retinal pericytes but not in endothelial cells. Treatment with RANK-Fc markedly reduced the NVT area compared to that in mice administered the IgG1 injection. In contrast, the central avascular region of RANKL-Fc retina was comparable to the controls. In addition, we assessed retinal vascular permeability using FITC-labeled dextran. RANK-Fc treated mice displayed decreased vascular leakages compared to those injected with IgG1. Our work supports the use of an RANKL blockade as a potential therapeutic approach against ischemic retinopathies.


Assuntos
Isquemia/patologia , Neovascularização Patológica/patologia , Ligante RANK/antagonistas & inibidores , Doenças Retinianas/patologia , Animais , Animais Recém-Nascidos , Permeabilidade Capilar , Hipóxia Celular , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Isquemia/complicações , Camundongos Endogâmicos C57BL , Neovascularização Patológica/complicações , Pericitos/metabolismo , Ligante RANK/metabolismo , Doenças Retinianas/complicações , Células Ganglionares da Retina/metabolismo
17.
Regul Toxicol Pharmacol ; 106: 7-14, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31009651

RESUMO

This study aimed to determine the safety and tolerability of the subretinal injection of hESC-derived RPE cells at higher doses than the established clinical dose (5 × 104 cells/150 µL) by using minipigs. The hESC-derived RPE cells (60 or 120 × 104 cells/150 µL) were injected in subretinal region, and minipigs were sacrificed at Weeks 4, 8, and 12 post-surgery. Time-course examination was performed by using fundus photography, optical coherence tomography (OCT), histopathology, and fluorescence in situ hybridization (FISH). After surgery, retinal bleb and pigmentation were seen and retinal bleb became smaller gradually. In histopathology, cell clusters consisting of a uniform population of the round to oval cells were seen at the subretinal injection site. In immunohistochemistry, most of the cells were positive for anti-CD3 and CD45 antibodies but negative for anti-human nuclei antibody; transplanted cells were not detectable by DNA probe in FISH assay. Cell clusters were thought to be a host immune response to trauma or transplanted cells. There were no other changes related to subretinal RPE cell injection. These results suggested that subretinal injection of hESC-derived RPE cells (60 and 120 × 104 cells/150 µL) in minipigs is well-tolerated and safe.


Assuntos
Células-Tronco Embrionárias Humanas/citologia , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/transplante , Segurança , Porco Miniatura , Animais , Humanos , Hibridização in Situ Fluorescente , Suínos , Tomografia de Coerência Óptica
18.
Ophthalmologica ; 239(4): 194-204, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29393235

RESUMO

PURPOSE: To evaluate whether early anatomical and visual acuity (VA) responses to intravitreal bevacizumab (IVB) in macular edema secondary to branch retinal vein occlusion (BRVO) are associated with 1-year follow-up outcomes. METHODS: Ninety-nine treatment-naïve patients (99 eyes) with macular edema after BRVO treated with IVB were analyzed retrospectively. All patients received single injection and were followed up with pro re nata regimen for at least 12 months. The relationship between early (1 month) and late (12 months) anatomical (presence/absence of fluid) and functional response (an improvement of <1, 1 to <3, or ≥3 logMAR lines from baseline in best corrected VA, BCVA) was explored. RESULTS: Fifty-eight eyes (58.6%) had absence of fluid at 1 month after the first injection, but 41 eyes (41.4%) did not. Those with absence of fluid at 1 month were more likely to be fluid-free at 12 months (p = 0.010). Thirty-seven (37.4%), 24 (24.2%), and 38 (38.4%) eyes showed an improvement of <1, 1 to <3, and ≥3 lines, respectively, at 1 month after the first injection. Intercohort differences across three response categories in BCVA change from baseline were statistically significant throughout the follow-up. Each group maintained stable VA changes within 1 line during the follow-up after 1 month. CONCLUSION: The early anatomical and functional response was associated with anatomical and functional improvement at 12 months.


Assuntos
Bevacizumab/administração & dosagem , Macula Lutea/patologia , Edema Macular/tratamento farmacológico , Oclusão da Veia Retiniana/complicações , Acuidade Visual , Inibidores da Angiogênese/administração & dosagem , Feminino , Angiofluoresceinografia , Seguimentos , Fundo de Olho , Humanos , Injeções Intravítreas , Edema Macular/etiologia , Edema Macular/fisiopatologia , Masculino , Pessoa de Meia-Idade , Oclusão da Veia Retiniana/diagnóstico , Oclusão da Veia Retiniana/tratamento farmacológico , Estudos Retrospectivos , Tomografia de Coerência Óptica , Resultado do Tratamento
19.
Ophthalmologica ; 237(3): 128-138, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28278507

RESUMO

PURPOSE: The aim of this study was to determine the correlation between the duration of myopic choroidal neovascularization (CNV) and treatment outcome after anti-vascular endothelial growth factor (VEGF) injections. METHODS: We performed a retrospective review of treatment-naïve myopic CNV patients who were treated with anti-VEGF and followed for at least 24 months to identify factors predicting final outcome and recurrence. RESULTS: Among 106 eyes, a shorter duration of CNV was a significant predictor of a better final best-corrected visual acuity, even after controlling for other factors (p = 0.042). When divided into 3 groups according to CNV duration before treatment (<2, 2-8, and 8-24 weeks), the recurrence rate (19, 25, and 52%, respectively; p = 0.006) and number of injections (3.5, 4.0, and 5.5, respectively; p = 0.021) were significantly lower in eyes with a shorter duration of CNV. CONCLUSIONS: Early anti-VEGF treatment of myopic CNV decreased the recurrence rate and number of injections and improved visual outcome.


Assuntos
Bevacizumab/administração & dosagem , Neovascularização de Coroide/tratamento farmacológico , Miopia Degenerativa/complicações , Ranibizumab/administração & dosagem , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual , Inibidores da Angiogênese/administração & dosagem , Neovascularização de Coroide/diagnóstico , Neovascularização de Coroide/etiologia , Feminino , Seguimentos , Humanos , Injeções Intravítreas , Masculino , Pessoa de Meia-Idade , Miopia Degenerativa/diagnóstico , Estudos Retrospectivos , Fatores de Tempo , Tomografia de Coerência Óptica , Resultado do Tratamento
20.
Antimicrob Agents Chemother ; 60(4): 2012-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26824952

RESUMO

Staphylococcus aureusbacteremia (SAB) often leads to ocular infections, including endophthalmitis and chorioretinitis. However, the incidence, risk factors, and outcomes of ocular infections complicated by SAB are largely unknown. We retrospectively analyzed the incidence and risk factors of ocular involvement in a prospective cohort of patients with SAB at a tertiary-care hospital. Ophthalmologists reviewed the fundoscopic findings and classified the ocular infections as endophthalmitis or chorioretinitis. During the 5-year study period, 1,109 patients had SAB, and data for 612 (55%) who underwent ophthalmic examinations within 14 days after SAB onset were analyzed. Of those 612 patients, 56 (9% [95% confidence interval [CI], 7 to 12%]) had ocular involvement, including 15 (2.5%) with endophthalmitis and 41 (6.7%) with chorioretinitis. In a multivariate analysis, infective endocarditis (adjusted odds ratio [aOR], 5.74 [95% CI, 2.25 to 14.64]) and metastatic infection (aOR, 2.38 [95% CI, 1.29 to 4.39]) were independent risk factors for ocular involvement. Of the 47 patients with ocular involvement who could communicate, only 17 (36%) had visual disturbances. Two-thirds of the patients with endophthalmitis (10/15 patients) were treated with intravitreal antibiotics combined with parenteral antibiotics, whereas all of the patients with chorioretinitis were treated only with systemic antibiotics. No patients became blind. Among 42 patients for whom follow-up assessments were available, the ocular lesions improved in 29 (69%) but remained the same in the others. Ocular involvement was independently associated with death within 30 days after SAB onset. Ocular involvement is not uncommon among patients with SAB. Routine ophthalmic examinations should be considered for patients with infective endocarditis or metastatic infections caused by SAB.


Assuntos
Bacteriemia/patologia , Coriorretinite/patologia , Endocardite Bacteriana/patologia , Endoftalmite/patologia , Infecções Estafilocócicas/patologia , Idoso , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Bacteriemia/mortalidade , Coriorretinite/tratamento farmacológico , Coriorretinite/mortalidade , Endocardite Bacteriana/tratamento farmacológico , Endocardite Bacteriana/mortalidade , Endoftalmite/tratamento farmacológico , Endoftalmite/mortalidade , Feminino , Humanos , Injeções Intravenosas , Injeções Intravítreas , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Prospectivos , Fatores de Risco , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/mortalidade , Staphylococcus aureus/patogenicidade , Staphylococcus aureus/fisiologia , Análise de Sobrevida , Centros de Atenção Terciária
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