RESUMEN

The retina transforms light into electrical signals, which are sent to the brain via the optic nerve to form our visual perception. This complex signal processing is performed by the retinal neuron and requires a significant amount of energy. Since neurons are unable to store energy, they must obtain glucose and oxygen from the bloodstream to produce energy to match metabolic needs. This process is called neurovascular coupling (NVC), and it is based on a precise mechanism that is not totally understood. The discovery of fine tubular processes termed tunnelling nanotubes (TNTs) set a new type of cell-to-cell communication. TNTs are extensions of the cellular membrane that allow the transfer of material between connected cells. Recently, they have been reported in the brain and retina of living mice, where they connect pericytes, which are vascular mural cells that regulate vessel diameter. Accordingly, these TNTs were termed interpericyte tunnelling nanotubes (IPTNTs), which showed a vital role in blood delivery and NVC. In this chapter, we review the involvement of TNTs in NVC and discuss their implications in retinal neurodegeneration.

Asunto(s)

Comunicación Celular , Retina , Animales , Humanos , Retina/fisiología , Comunicación Celular/fisiología , Pericitos/fisiología , Nanotubos , Ratones , Acoplamiento Neurovascular/fisiología , Vasos Retinianos/fisiología , Estructuras de la Membrana Celular

RESUMEN

PURPOSE: This study was performed to assess the prevalence of the vascularized foveal zone, including macular-foveal capillaries (MFC) and congenital retinal macrovessels (CRM), and to analyze the structural characteristics of the macular area in patients with MFC. MATERIAL AND METHODS: The first phase of the study evaluated the prevalence of MFC and CRM. Optical coherence tomography angiography (OCT-A) was performed, and OCT-A images of the foveal avascular zone were analyzed. In the second phase, two groups were formed: the MFC group (12 eyes, 9 patients, mean age 43.8±10.7 years) and the control group (18 eyes, 17 patients, mean age 43.0±11.8 years). A comparative analysis was performed assessing central retinal thickness (CRT), thickness of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), and foveal pit depth. RESULTS: MFCs were detected in 45 eyes from a total sample of 1031 eyes of 536 patients. The presence of CRM was recorded in three eyes of three patients. RNFL thickness was significantly higher in the MFC group in the inferior parafoveal sector (26.50 [26.00; 29.50] and 24.50 [21.75; 26.50] µm; p=0.022) and in the foveal zone (15.50 [14.00; 16.00] and 12.00 [11.00; 14.00] µm; p=0.017). Additionally, patients with MFC had a higher thickness of GCL and IPL in the fovea, inferior, nasal, and temporal parafoveal sectors. The depth of the foveal pit was significantly lower in the MFC group compared to the control group (83.0 [77.4; 101.6] and 128.0 [107.5; 147.05] µm; p=0.001). CONCLUSION: The prevalence of MFC was 4.36% (calculated per number of eyes), while the prevalence of CRM - 0.29%. The macular area in patients with MFC had increased thickness of the inner retinal layers and decreased depth of the foveal pit, suggesting potential disruption in the natural process of ganglion cell migration and apoptosis during embryogenesis.

Asunto(s)

Fóvea Central , Vasos Retinianos , Tomografía de Coherencia Óptica , Humanos , Fóvea Central/irrigación sanguínea , Fóvea Central/diagnóstico por imagen , Adulto , Femenino , Masculino , Tomografía de Coherencia Óptica/métodos , Prevalencia , Persona de Mediana Edad , Vasos Retinianos/diagnóstico por imagen , Capilares/diagnóstico por imagen , Capilares/patología , Enfermedades de la Retina/epidemiología , Enfermedades de la Retina/diagnóstico , Enfermedades de la Retina/etiología , Federación de Rusia/epidemiología , Agudeza Visual , Angiografía con Fluoresceína/métodos

RESUMEN

Optical Coherence Tomography Angiography (OCTA) is a crucial tool in the clinical screening of retinal diseases, allowing for accurate 3D imaging of blood vessels through non-invasive scanning. However, the hardware-based approach for acquiring OCTA images presents challenges due to the need for specialized sensors and expensive devices. In this paper, we introduce a novel method called TransPro, which can translate the readily available 3D Optical Coherence Tomography (OCT) images into 3D OCTA images without requiring any additional hardware modifications. Our TransPro method is primarily driven by two novel ideas that have been overlooked by prior work. The first idea is derived from a critical observation that the OCTA projection map is generated by averaging pixel values from its corresponding B-scans along the Z-axis. Hence, we introduce a hybrid architecture incorporating a 3D adversarial generative network and a novel Heuristic Contextual Guidance (HCG) module, which effectively maintains the consistency of the generated OCTA images between 3D volumes and projection maps. The second idea is to improve the vessel quality in the translated OCTA projection maps. As a result, we propose a novel Vessel Promoted Guidance (VPG) module to enhance the attention of network on retinal vessels. Experimental results on two datasets demonstrate that our TransPro outperforms state-of-the-art approaches, with relative improvements around 11.4% in MAE, 2.7% in PSNR, 2% in SSIM, 40% in VDE, and 9.1% in VDC compared to the baseline method. The code is available at: https://github.com/ustlsh/TransPro.

Asunto(s)

Imagenología Tridimensional , Vasos Retinianos , Tomografía de Coherencia Óptica , Tomografía de Coherencia Óptica/métodos , Humanos , Vasos Retinianos/diagnóstico por imagen , Imagenología Tridimensional/métodos , Heurística , Enfermedades de la Retina/diagnóstico por imagen , Algoritmos , Angiografía/métodos

RESUMEN

PURPOSE: To evaluate the findings and the correlation of optical coherence tomography angiography and pattern and flash electroretinography in diabetes mellitus without retinopathy. METHODS: Seventy-six eyes of 38 diabetic patients and age- and gender-matched control subjects were included in the study. The foveal avascular zone (FAZ), whole, foveal, parafoveal and perifoveal vascular densities of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillary plexus (CCP) layers were analyzed using optical coherence tomography angiography (OCTA). The amplitudes and implicit times of P50 and N95 waves of the pattern ERG (pERG) and the amplitudes and implicit times of the scotopic and photopic b-waves and oscillatory potentials (OP) of the flash ERG (fERG) tests were evaluated using the Metrovision brand monpack model device. RESULTS: The mean age of the patients was 59.7 ± 7.9 [range 43-79] years. Eighteen (47%) of the patients were female and 20 (53%) were male. The mean duration of diabetes was 7.45 ± 6.2 [range 1-20] years. No significant difference in FAZ area was found between study subjects and controls. Vascular density (VD) values of the superficial capillary plexus (SCP) layer were significantly lower (whole VD, 44.7 ± 3.3 vs. 46.6 ± 3.2%, p = 0.01, foveal VD 16.8 ± 6.4 vs. 24.9 ± 6.1%, p < 0.01, parafoveal VD 45.6 ± 4.5 vs. 47.1 ± 4.4%, p = 0.27 and perifoveal VD 45.5 ± 3.3 vs. 47.3 ± 3.1%, p = 0.01, respectively) in the diabetic group except the parafoveal area. VD measurements in deep and choriocapillary plexuses did not significantly differ between the groups (p > 0.05). ERG tests revealed significantly lower scotopic b-wave amplitudes (130.2 ± 39.3 µV vs.163.3 ± 47.8 µV, p < 0.01) and photopic b-wave amplitudes (83.2 ± 20.7 µV vs. 99.6 ± 29.4 µV, p < 0.01) in the diabetic patients. The implicit time of the photopic responses was significantly prolonged (28.9 ± 1.3 ms vs. 27.8 ± 2.1 ms, p = 0.01) in the patients. Oscillatory potentials in all components consisting of O1 to O4 and the sum of the OP potentials were lower in the diabetic group than the control subjects (p < 0.001). The P50 and N95 amplitudes and implicit times were comparable between the groups (p > 0.05). Correlation analysis showed a positive correlation between N95 amplitudes in pERG and the superficial vessel densities in OCTA (r = 0.26, p = 0.04). A negative correlation was found between photopic implicit times in fERG and the choriocapillary vessel densities (r=-0.27, p = 0.03). CONCLUSION: OCTA revealed decreased superficial vascular densities with the onset of the metabolic process of diabetes mellitus. As a result of these structural changes, lower scotopic and photopic amplitudes, decreased OP amplitudes, and prolonged implicit times in flash ERG were obtained.

Asunto(s)

Electrorretinografía , Tomografía de Coherencia Óptica , Humanos , Electrorretinografía/métodos , Masculino , Tomografía de Coherencia Óptica/métodos , Femenino , Persona de Mediana Edad , Anciano , Adulto , Angiografía con Fluoresceína/métodos , Retinopatía Diabética/fisiopatología , Retinopatía Diabética/diagnóstico por imagen , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/fisiopatología , Estudios de Casos y Controles , Fóvea Central/diagnóstico por imagen , Fóvea Central/irrigación sanguínea , Fóvea Central/fisiopatología , Diabetes Mellitus/fisiopatología , Diabetes Mellitus/diagnóstico por imagen , Retina/diagnóstico por imagen , Retina/fisiopatología

RESUMEN

Purpose: To assess the correspondence between interdigitation zone (IZ) reflectivity, ellipsoid zone (EZ) loss, inner retinal layer reflectivity, patterns of capillary dilation, and telangiectasia in eyes with early macular telangiectasia type 2 (MacTel). Patients and Methods: Twenty-eight eyes of 22 patients with grade 0-2 MacTel (according to the MacTel project classification) and 28 healthy control eyes were included in this study. Multimodal imaging, including optical coherence tomography (OCT) angiography, adaptive optics flood illumination ophthalmoscopy (AO-FIO) and blue light reflectance (BLR), was performed. The EZ, IZ, and outer plexiform layer (OPL) were analyzed on the structural OCT C-scans. The vascular density (VD) was measured on the binarized and skeletonized angiograms of the superficial vascular plexus and deep capillary complex. The vascular diameter index (VDI) was calculated by dividing the binarized VD by the skeletonized VD. Results: On AO-FIO, cone density in the MacTel zone was significantly lower in MacTel eyes than in controls, even in areas located outside the EZ loss (P < 0.001). A distinctive pattern of IZ reflectivity attenuation extended beyond the area of EZ attenuation. The shape and size of a strong OPL hyper-reflectivity corresponded to the MacTel white area (MacTel zone) seen on BLR. Capillary dilation and rarefaction were colocalized with this area, extending beyond visible telangiectasia. The VDI was higher in MacTel eyes than in controls (P < 0.001). Conclusions: These findings suggest that in early MacTel eyes, photoreceptor signal alteration, OPL hyper-reflectivity, and capillary dilation, potentially associated with Müller cell dysfunction, precede the EZ loss.

Asunto(s)

Angiografía con Fluoresceína , Oftalmoscopía , Telangiectasia Retiniana , Vasos Retinianos , Tomografía de Coherencia Óptica , Humanos , Tomografía de Coherencia Óptica/métodos , Femenino , Telangiectasia Retiniana/diagnóstico , Telangiectasia Retiniana/fisiopatología , Telangiectasia Retiniana/diagnóstico por imagen , Masculino , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/patología , Angiografía con Fluoresceína/métodos , Persona de Mediana Edad , Anciano , Agudeza Visual/fisiología , Fondo de Ojo , Imagen Multimodal , Adulto , Capilares/patología , Capilares/diagnóstico por imagen

RESUMEN

Purpose: Insight into the immune status of the living eye is essential as we seek to understand ocular disease and develop new treatments. The nonhuman primate (NHP) is the gold standard preclinical model for therapeutic development in ophthalmology, owing to the similar visual system and immune landscape in the NHP relative to the human. Here, we demonstrate the utility of phase-contrast adaptive optics scanning light ophthalmoscope (AOSLO) to visualize immune cell dynamics on the cellular scale, label-free in the NHP. Methods: Phase-contrast AOSLO was used to image preselected areas of retinal vasculature in five NHP eyes. Images were registered to correct for eye motion, temporally averaged, and analyzed for immune cell activity. Cell counts, dimensions, velocities, and frequency per vessel were determined manually and compared between retinal arterioles and venules. Based on cell appearance and circularity index, cells were divided into three morphologies: ovoid, semicircular, and flattened. Results: Immune cells were observed migrating along vascular endothelium with and against blood flow. Cell velocity did not significantly differ between morphology or vessel type and was independent of blow flood. Venules had a significantly higher cell frequency than arterioles. A higher proportion of cells resembled "flattened" morphology in arterioles. Based on cell speeds, morphologies, and behaviors, we identified these cells as nonclassical patrolling monocytes (NCPMs). Conclusions: Phase-contrast AOSLO has the potential to reveal the once hidden behaviors of single immune cells in retinal circulation and can do so without the requirement of added contrast agents that may disrupt immune cell behavior.

Asunto(s)

Macaca mulatta , Vasos Retinianos , Animales , Masculino , Oftalmoscopía/métodos , Movimiento Celular/fisiología , Vénulas , Arteriolas , Microscopía de Contraste de Fase , Oftalmoscopios , Macaca fascicularis

RESUMEN

Familial exudative vitreoretinopathy (FEVR) is a severe genetic disorder characterized by incomplete vascularization of the peripheral retina and associated symptoms that can lead to vision loss. However, the underlying genetic causes of approximately 50% of FEVR cases remain unknown. Here, we report two heterozygous variants in calcyphosine-like gene (CAPSL) that is associated with FEVR. Both variants exhibited compromised CAPSL protein expression. Vascular endothelial cell (EC)-specific inactivation of Capsl resulted in delayed radial/vertical vascular progression, compromised endothelial proliferation/migration, recapitulating the human FEVR phenotypes. CAPSL-depleted human retinal microvascular endothelial cells (HRECs) exhibited impaired tube formation, decreased cell proliferation, disrupted cell polarity establishment, and filopodia/lamellipodia formation, as well as disrupted collective cell migration. Transcriptomic and proteomic profiling revealed that CAPSL abolition inhibited the MYC signaling axis, in which the expression of core MYC targeted genes were profoundly decreased. Furthermore, a combined analysis of CAPSL-depleted HRECs and c-MYC-depleted human umbilical vein endothelial cells uncovered similar transcription patterns. Collectively, this study reports a novel FEVR-associated candidate gene, CAPSL, which provides valuable information for genetic counseling of FEVR. This study also reveals that compromised CAPSL function may cause FEVR through MYC axis, shedding light on the potential involvement of MYC signaling in the pathogenesis of FEVR.

Asunto(s)

Vitreorretinopatías Exudativas Familiares , Humanos , Vitreorretinopatías Exudativas Familiares/genética , Células Endoteliales/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Animales , Neovascularización Retiniana/genética , Neovascularización Retiniana/metabolismo , Neovascularización Retiniana/patología , Movimiento Celular/genética , Proliferación Celular/genética , Ratones , Vasos Retinianos/metabolismo , Vasos Retinianos/patología , Masculino , Neovascularización Patológica/genética , Transducción de Señal , Femenino , Angiogénesis

RESUMEN

Diabetic retinopathy is a common yet severe complication of diabetes mellitus and is the leading cause of blindness in middle-aged adults. After years of poorly managed hyperglycemia, complications begin as non-proliferative diabetic retinopathy but can then progress into the proliferative stage marked by neovascularization of the retina. Multiple pathologic mechanisms caused by chronic hyperglycemia damage the retinal vasculature leading to pericyte drop out and the progression of the disease. This review outlines the major pathways of pathogenesis in diabetic retinopathy, highlighting the protective role pericytes play in preserving the blood-retinal barrier. Given the loss of this cell line is a defining feature of the disease, ways in which to prevent pericyte dropout within retinal vasculature is discussed, targeting various pathogenesis pathways of diabetic retinopathy.

Asunto(s)

Barrera Hematorretinal , Retinopatía Diabética , Pericitos , Retinopatía Diabética/patología , Retinopatía Diabética/metabolismo , Pericitos/metabolismo , Pericitos/patología , Humanos , Barrera Hematorretinal/metabolismo , Animales , Vasos Retinianos/patología , Vasos Retinianos/metabolismo

RESUMEN

Diabetic retinopathy is one of the leading causes of blindness around the world. This makes early diagnosis and treatment important in preventing vision loss in a large number of patients. Microaneurysms are the key hallmark of the early stage of the disease, non-proliferative diabetic retinopathy, and can be detected using OCT angiography quickly and non-invasively. Screening tools for non-proliferative diabetic retinopathy using OCT angiography thus have the potential to lead to improved outcomes in patients. We compared different configurations of ensembled U-nets to automatically segment microaneurysms from OCT angiography fundus projections. For this purpose, we created a new database to train and evaluate the U-nets, created by two expert graders in two stages of grading. We present the first U-net neural networks using ensembling for the detection of microaneurysms from OCT angiography en face images from the superficial and deep capillary plexuses in patients with non-proliferative diabetic retinopathy trained on a database labeled by two experts with repeats.

Asunto(s)

Retinopatía Diabética , Microaneurisma , Tomografía de Coherencia Óptica , Retinopatía Diabética/diagnóstico por imagen , Humanos , Microaneurisma/diagnóstico por imagen , Tomografía de Coherencia Óptica/métodos , Redes Neurales de la Computación , Angiografía/métodos , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/patología , Angiografía con Fluoresceína/métodos

RESUMEN

Glaucoma is a group of neurodegenerative diseases that can lead to irreversible blindness. Yet, the progression can be slowed down if diagnosed and treated early enough. Optical coherence tomography angiography (OCTA) can non-invasively provide valuable information about the retinal microcirculation that has shown to be correlated with the onset of the disease. The vessel density (VD) is the most commonly used biomarker to quantify this vascular information. However, different studies showed that there is a great impact of the acquisition area on the performance of the VD to distinguish between glaucoma patients and a healthy control group. It also seems that the separate capillary plexuses are differently affected by the disease and therefore also influence the results. So in this study we investigate the impact of the acquisition area (3 × 3 mm macular scan, 6.44 × 6.4 mm macular scan, 6 × 6 mm optic nerve head (ONH) scan) and the different plexuses on the machine-learning-based distinction between glaucoma patients and healthy controls. The results yielded that the 6 × 6 mm ONH show the best performance over all plexuses. Moreover the deep learning-based approach outperforms the VD as a biomarker on every acquisition area and plexus. In addition to that, it also performs better than traditional biomarkers obtained from the OCT scans that are used in the clinical routine for diagnosis and progression tracking of glaucoma. Consequently, OCTA scans of the ONH might be a useful addition to OCT when studying glaucoma.

Asunto(s)

Aprendizaje Profundo , Glaucoma , Disco Óptico , Tomografía de Coherencia Óptica , Humanos , Tomografía de Coherencia Óptica/métodos , Glaucoma/diagnóstico , Glaucoma/diagnóstico por imagen , Disco Óptico/diagnóstico por imagen , Masculino , Femenino , Persona de Mediana Edad , Vasos Retinianos/diagnóstico por imagen , Anciano , Estudios de Casos y Controles

RESUMEN

This study was intended to investigate the macular vascular and photoreceptor changes for diabetic macular edema (DME) at the early stage. A total of 255 eyes of 134 diabetes mellitus patients were enrolled and underwent an ophthalmological and systemic evaluation in this cross-sectional study. Early DME was characterized by central subfoveal thickness (CST) value between 250 and 325 µm, intact ellipsoid zone, and an external limiting membrane. While non-DME was characterized by CST < 250 µm with normal retinal morphology and structure. Foveal avascular zone (FAZ) area ≤ 0.3 mm2 (P < 0.001, OR = 0.41, 95% CI 0.26-0.67 in the multivariate analysis) and HbA1c level ≤ 8% (P = 0.005, OR = 0.37, 95% CI 0.19-0.74 in multivariate analysis) were significantly associated with a higher risk of early DME. Meanwhile, no significant differences exist in cone parameters between non-DME and early DME eyes. Compared with non-DME eyes, vessel diameter, vessel wall thickness, wall-to-lumen ratio, the cross-sectional area of the vascular wall in the upper side were significantly decreased in the early DME eyes (P = 0.001, P < 0.001, P = 0.005, P = 0.003 respectively). This study suggested a vasospasm or vasoconstriction with limited further photoreceptor impairment at the early stage of DME formation. CST ≥ 250 µm and FAZ ≤ 0.3 mm2 may be the indicator for early DME detection.

Asunto(s)

Retinopatía Diabética , Edema Macular , Vasos Retinianos , Humanos , Edema Macular/patología , Edema Macular/etiología , Edema Macular/diagnóstico por imagen , Masculino , Femenino , Retinopatía Diabética/patología , Retinopatía Diabética/diagnóstico por imagen , Persona de Mediana Edad , Estudios Transversales , Anciano , Vasos Retinianos/patología , Vasos Retinianos/diagnóstico por imagen , Mácula Lútea/patología , Mácula Lútea/diagnóstico por imagen , Tomografía de Coherencia Óptica/métodos , Fóvea Central/patología , Fóvea Central/diagnóstico por imagen

RESUMEN

In patients with Alzheimer's disease (AD) and in animal models, the increased accumulation of amyloid ß (Aß) in retinal blood vessels strongly correlates with brain amyloid deposits and cognitive decline. The accumulation of Aß in blood vessels may result from impaired transcytosis and a dysfunctional ocular glymphatic system in AD. High-dose fish oil (FO) supplementation has been shown to significantly change the expression of major facilitator superfamily domain-containing protein 2a (Mfsd2a), a key regulator of transcytosis, and Aquaporin 4 (Aqp4), an essential component of the glymphatic system in the retinas of WT mice. We examined the expression of Mfsd2a and Aqp4 in the retinas of 4-month-old 5xFAD female mice supplemented with high-dose FO for three weeks. There was a significant increase in Mfsd2a expression in 5xFAD retinas supplemented with FO compared to control 5xFAD mice. Additionally, the increase in Aqp4 expression observed in 4-month-old 5xFAD retinas, indicative of an impaired glymphatic system, was significantly decreased. Simultaneously, Aß accumulation in 5xFAD retinal blood vessels was reduced following FO supplementation. These findings suggest that high-dose FO supplementation could serve as an adjunct in developing new treatments aimed at improving the regulation of transcytosis or the function of the glymphatic system in the AD retina.

Asunto(s)

Enfermedad de Alzheimer , Péptidos beta-Amiloides , Acuaporina 4 , Suplementos Dietéticos , Modelos Animales de Enfermedad , Aceites de Pescado , Ratones Transgénicos , Vasos Retinianos , Animales , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/genética , Acuaporina 4/metabolismo , Acuaporina 4/genética , Péptidos beta-Amiloides/metabolismo , Ratones , Femenino , Vasos Retinianos/metabolismo , Vasos Retinianos/efectos de los fármacos , Aceites de Pescado/farmacología , Aceites de Pescado/administración & dosificación , Simportadores/metabolismo , Simportadores/genética , Humanos

RESUMEN

BACKGROUND: Emerging evidence points to the beneficial role of greenspace exposure in promoting cardiovascular health. Most studies have evaluated such associations with conventional cardiovascular endpoints such as mortality, morbidity, or macrovascular markers. In comparison, the microvasculature, a crucial compartment of the vascular system where early subclinical signs of cardiovascular problems appear, has not been studied in association with greenspace exposure. The current study assessed the association between surrounding greenness and microvascular status, as assessed by retinal vessel diameters. METHODS: This study included a sample of healthy adults (n = 114 and 18-65 years old) residing in three European cities [Antwerp (Belgium), Barcelona (Spain), and London (UK)]. The exposures to greenspace at the home and work/school locations were characterized as average surrounding greenness [normalized difference vegetation index (NDVI)] within buffers of 100 m, 300 m, and 500 m. The central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were calculated from fundus pictures taken at three different time points. We developed linear mixed-effect models to estimate the association of greenspace exposure with indicators of retinal microvasculature, adjusted for relevant individual and area-level covariates. RESULTS: We observed the most robust associations with CRVE. Higher levels of greenspace at work/school were associated with smaller retinal venules [(seasonal NDVI) 300m: 3.85, 95%CI -6.67,-1.03; 500m: 5.11, 95%CI -8.04, -2.18]. Findings for surrounding greenness and CRAE were not conclusive. CONCLUSION: Our study suggests an association of greenspace exposure with better microvascular status, specifically for retinal venules. Future research is needed to confirm our findings across different contextual settings.

Asunto(s)

Microvasos , Vasos Retinianos , Humanos , Masculino , Adulto , Femenino , Persona de Mediana Edad , Bélgica , Anciano , Ciudades , España , Adolescente , Londres , Adulto Joven

RESUMEN

BACKGROUND: We aimed to evaluate microaneurysms (MAs) after treatment with anti-vascular endothelial growth factor (anti-VEGF) therapy to understand causes of chronic edema and anti-VEGF resistance. METHODS: Patients with non-proliferative diabetic retinopathy, with or without macular edema were recruited. Optical coherence tomography angiography (OCTA) MAs-related parameters were observed, including the maximum diameter of overall dimensions, material presence, and flow signal within the lumen. OCTA parameters also included central macular thickness (CMT), foveal avascular zone, superficial and deep capillary plexuses, and non-flow area measurements on the superficial retinal slab. RESULTS: Overall, 48 eyes from 43 patients were evaluated. CMT differed significantly between the diabetic macular edema (DME ) and non-DME (NDME) groups at 1st, 2nd, 3rd, and 6th months of follow-up (P < 0.001; <0.001; 0.003; <0.001, respectively). A total of 55 and 59 MAs were observed in the DME (mean = 99.40 ± 3.18 µm) and NDME (mean maximum diameter = 74.70 ± 2.86 µm) groups at baseline, respectively (significant between-group difference: P < 0.001). Blood flow signal was measurable for 46 (83.6%) and 34 (59.3%) eyes in the DME and NDME groups, respectively (significant between-group difference: P < 0.001). CONCLUSIONS: Compared to the NDME group, the DME group had larger MAs and a higher blood-flow signal ratio. Following anti-VEGF therapy, changes in the diameter of MAs were observed before changes in CMT thickness.

Asunto(s)

Inhibidores de la Angiogénesis , Retinopatía Diabética , Angiografía con Fluoresceína , Inyecciones Intravítreas , Edema Macular , Microaneurisma , Tomografía de Coherencia Óptica , Factor A de Crecimiento Endotelial Vascular , Agudeza Visual , Humanos , Tomografía de Coherencia Óptica/métodos , Retinopatía Diabética/tratamiento farmacológico , Retinopatía Diabética/diagnóstico , Edema Macular/tratamiento farmacológico , Edema Macular/etiología , Edema Macular/diagnóstico por imagen , Edema Macular/diagnóstico , Masculino , Microaneurisma/diagnóstico , Femenino , Persona de Mediana Edad , Inhibidores de la Angiogénesis/uso terapéutico , Angiografía con Fluoresceína/métodos , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Anciano , Ranibizumab/uso terapéutico , Ranibizumab/administración & dosificación , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/patología , Fondo de Ojo , Estudios de Seguimiento

RESUMEN

BACKGROUND: Low-density lipoprotein cholesterol (LDL-C) is acknowledged as an independent risk factor (IRF) for atherosclerotic cardiovascular disease. Nevertheless, studies on the impact of LDL-C on microvasculature are still scarce. The retina, abundant in microvasculature, can now be examined for microvascular alterations through the novel, non-invasive, and quantitative optical coherence tomography angiography (OCTA) technique. METHODS: In this cross-sectional study, 243 patients from the geriatric department were recruited (between December 2022 and December 2023). Individuals were classified into four groups based on their LDL-C levels: Group 1 (≤ 1.8 mmol/L), Group 2 (> 1.8 mmol/L to ≤ 2.6 mmol/L), Group 3 (> 2.6 mmol/L to ≤ 3.4 mmol/L), and Group 4 (> 3.4 mmol/L). The OCTA results including retinal vessel density (VD), foveal avascular zone (FAZ) area, macula thickness, and retinal nerve fiber layer (RNFL) thickness were contrasted across these groups. T-tests, analysis of variance, Welch's tests, or rank-sum tests were employed for statistical comparisons. In cases where significant differences between groups were found, post-hoc multiple comparisons or rank-sum tests were performed for pairwise group comparisons. Spearman's correlation coefficient was employed to perform bivariate correlation analysis to evaluate the relationship between LDL-C levels and various OCTA measurements. Multivariable regression analysis was used to evaluate the association between LDL-C levels and various OCTA measurements. Linear regression analysis or mixed-effects linear models were applied. RESULTS: It was discovered that individuals with LDL-C levels exceeding 2.6 mmol/L (Groups 3 and 4) exhibited reduced VD in the retina, encompassing both the optic disc and macular regions, compared to those with LDL-C levels at or below 2.6 mmol/L (Groups 1 and 2). A negative correlation among LDL-C levels and retinal VD was identified, with r values spanning from - 0.228 to -0.385. Further regression analysis presented ß values between - 0.954 and - 2.378. Additionally, no notable disparities were detected among the groups regarding FAZ area, macular thickness, and RNFL thickness. CONCLUSIONS: The outcomes of this study suggest that elevated LDL-C levels constitute an IRF for decreased VD across the entire retina. TRIAL REGISTRATION: NCT05644548, December 1, 2022.

Asunto(s)

LDL-Colesterol , Vasos Retinianos , Tomografía de Coherencia Óptica , Humanos , Tomografía de Coherencia Óptica/métodos , Masculino , Femenino , Vasos Retinianos/diagnóstico por imagen , LDL-Colesterol/sangre , Anciano , Estudios Transversales , Persona de Mediana Edad , Anciano de 80 o más Años , Mácula Lútea/diagnóstico por imagen , Mácula Lútea/irrigación sanguínea , Factores de Riesgo

RESUMEN

Deep learning plays a pivotal role in retinal blood vessel segmentation for medical diagnosis. Despite their significant efficacy, these techniques face two major challenges. Firstly, they often neglect the severe class imbalance in fundus images, where thin vessels in the foreground are proportionally minimal. Secondly, they are susceptible to poor image quality and blurred vessel edges, resulting in discontinuities or breaks in vascular structures. In response, this paper proposes the Skeleton-guided Multi-scale Dual-coordinate Attention Aggregation (SMDAA) network for retinal vessel segmentation. SMDAA comprises three innovative modules: Dual-coordinate Attention (DCA), Unbalanced Pixel Amplifier (UPA), and Vessel Skeleton Guidance (VSG). DCA, integrating Multi-scale Coordinate Feature Aggregation (MCFA) and Scale Coordinate Attention Decoding (SCAD), meticulously analyzes vessel structures across various scales, adept at capturing intricate details, thereby significantly enhancing segmentation accuracy. To address class imbalance, we introduce UPA, dynamically allocating more attention to misclassified pixels, ensuring precise extraction of thin and small blood vessels. Moreover, to preserve vessel structure continuity, we integrate vessel anatomy and develop the VSG module to connect fragmented vessel segments. Additionally, a Feature-level Contrast (FCL) loss is introduced to capture subtle nuances within the same category, enhancing the fidelity of retinal blood vessel segmentation. Extensive experiments on three public datasets (DRIVE, STARE, and CHASE_DB1) demonstrate superior performance in comparison to current methods. The code is available at https://github.com/wangwxr/SMDAA_NET.

Asunto(s)

Aprendizaje Profundo , Vasos Retinianos , Humanos , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/anatomía & histología , Procesamiento de Imagen Asistido por Computador/métodos , Interpretación de Imagen Asistida por Computador/métodos

RESUMEN

To investigate neurovascular changes; including macular vascular density (VD), thickness of the ganglion cell layer (GCL) and optic nerve head (ONH) parameters in episodic migraine patients. 80 eyes of 40 episodic migraine patients were recruited. Thirty patients having a dominant side of migraine headache were statistically analyzed (5 male and 25 female; mean age 31.67 ± 9.54 years) and compared to 25 eyes of 25 healthy volunteers (5 male and 20 female; mean age of 34.4 ± 12.11 years, p = 0.361). The posterior segment was imaged with Topcon DRI optical coherence tomography (OCT) (Triton Swept source OCT Topcon, Japan), and OCT angiography (OCTA). Comparing the dominant side of migraine patients to controls we found a significant decrease of the VD in the central zone of the superficial and deep capillary plexus (SCP, p = 0.01; DCP, p = 0.004) and an enlarged foveal avascular zone (FAZ, p = 0.054). The GCL thickness was significantly reduced in the central ring (GCL + p = 0.042, GCL + + p = 0.029), as well as the retinal nerve fiber layer (RNFL) thickness in the temporal quadrant (p = 0.021) and border tissue of Elschnig diameter (BTE, p = 0.035). The duration of migraine showed an inverse correlation with SCP in the nasal quadrant (p = 0.016, r = - 0.445) and with all DCP regions [DCP superior (p = 0.004, r = - 0.519), DCP inferior (p = 0.004, r = - 0.519), DCP nasal (p = 0.006, r = - 0.496), DCP temporal (p = 0.005, r = - 0.508), DCP CSF (p < 0.001, r = - 0.634)]. The dominant side compared to the non-dominant side showed a significant deterioration of the VD in the inferior (p = 0.04) and temporal quadrants (p = 0.023); furthermore, a significant decrease in the GCL + + inner ring thickness (p = 0.046). Microvascular damage and consequent structural alterations of the retina and optic nerve head occur in the eyes of episodic migraine patient in association with the lateralization of the headache.

Asunto(s)

Trastornos Migrañosos , Disco Óptico , Tomografía de Coherencia Óptica , Humanos , Masculino , Femenino , Trastornos Migrañosos/patología , Trastornos Migrañosos/diagnóstico por imagen , Trastornos Migrañosos/fisiopatología , Adulto , Disco Óptico/irrigación sanguínea , Disco Óptico/patología , Disco Óptico/diagnóstico por imagen , Tomografía de Coherencia Óptica/métodos , Retina/patología , Retina/diagnóstico por imagen , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/patología , Células Ganglionares de la Retina/patología , Persona de Mediana Edad , Adulto Joven

RESUMEN

There is a lack of knowledge about the effect of flavanols-rich dark chocolate intake on the anatomy and functionality of retinal vessels. The aim of this study prospective, randomized, blind, crossover clinical trial (ClinicalTrials.gov Identifier: NCT05227248, 07/02/2022) was to evaluate the effect of dark-chocolate intake on the functionality and anatomy of the retinal vessels in healthy subjects using dynamic vessel analyzer (DVA) and optical coherence tomography angiography (OCT-A). Twenty eyes of 20 healthy subjects (mean age, 24.4 ± 1.6 years; 12 females) were enrolled. Participants were randomized to consume 20 g of dark chocolate or 7.5 g of milk chocolate. Visual function, DVA and OCT-A parameters were evaluated before chocolate consumption and two hours later. One week later, the same participants were tested before and after consuming the opposite chocolate. Using OCT-A, no differences were disclosed in terms of perfusion density changes after dark-chocolate and milk-chocolate intake analyzing all chorioretinal plexuses (p > 0.09 in all analyses). Using DVA, a significant increase in the arterial dilation percentage after flicker stimulation was disclosed comparing baseline (2.750 ± 2.054%) with values after the dark chocolate intake (4.145 ± 3.055%, p = 0.016). This difference was not disclosed after the milk chocolate intake (p = 0.465). We disclosed that a reasonable amount of flavanols-rich chocolate in healthy subjects has benefic functional short-term effects in retinal vessels measured with DVA. This suggests a potential role of dark chocolate intake on retinal vessels. Further studies with long-term follow-up are warranted to show if the chronic assumption of dark chocolate could play a favorable role in the prevention of retinal diseases.

Asunto(s)

Chocolate , Estudios Cruzados , Vasos Retinianos , Tomografía de Coherencia Óptica , Humanos , Femenino , Masculino , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/fisiología , Adulto , Adulto Joven , Estudios Prospectivos , Voluntarios Sanos

Asunto(s)

Fibrilación Atrial , Humanos , Fibrilación Atrial/complicaciones , Masculino , Femenino , Anciano , Accidente Cerebrovascular/etiología , Vasos Retinianos/patología , Vasos Retinianos/diagnóstico por imagen , Factores de Riesgo , Enfermedades de la Retina/etiología , Enfermedades de la Retina/diagnóstico , Persona de Mediana Edad

RESUMEN

Despite the significant advancements facilitated by previous research in introducing a plethora of retinal biomarkers, there is a lack of research addressing the clinical need for quantifying different biomarkers and prioritizing their importance for guiding clinical decision making in the context of retinal diseases. To address this issue, our study introduces a novel framework for quantifying biomarkers derived from optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images in retinal diseases. We extract 452 feature parameters from five feature types, including local binary patterns (LBP) features of OCT and OCTA, capillary and large vessel features, and the foveal avascular zone (FAZ) feature. Leveraging this extensive feature set, we construct a classification model using a statistically relevant p value for feature selection to predict retinal diseases. We obtain a high accuracy of 0.912 and F1-score of 0.906 in the task of disease classification using this framework. We find that OCT and OCTA's LBP features provide a significant contribution of 77.12% to the significance of biomarkers in predicting retinal diseases, suggesting their potential as latent indicators for clinical diagnosis. This study employs a quantitative analysis framework to identify potential biomarkers for retinal diseases in OCT and OCTA images. Our findings suggest that LBP parameters, skewness and kurtosis values of capillary, the maximum, mean, median, and standard deviation of large vessel, as well as the eccentricity, compactness, flatness, and anisotropy index of FAZ, may serve as significant indicators of retinal conditions.

Asunto(s)

Biomarcadores , Enfermedades de la Retina , Tomografía de Coherencia Óptica , Tomografía de Coherencia Óptica/métodos , Humanos , Enfermedades de la Retina/diagnóstico por imagen , Enfermedades de la Retina/diagnóstico , Enfermedades de la Retina/patología , Retina/diagnóstico por imagen , Retina/patología , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/patología , Algoritmos , Procesamiento de Imagen Asistido por Computador/métodos , Masculino