The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
Eckhard Wolf - One of the best experts on this subject based on the ideXlab platform.
-
retinopathy with central oedema in an ins c94y transgenic pig model of long term diabetes
Diabetologia, 2017Co-Authors: Kristina J H Kleinwort, Barbara Amann, Stefanie M Hauck, Sieglinde Hirmer, Andreas Blutke, Simone Renner, Patrizia B Uhl, Karina Lutterberg, Walter Sekundo, Eckhard WolfAbstract:Diabetic retinopathy is a severe complication of diabetes mellitus that often leads to blindness. Because the pathophysiology of diabetic retinopathy is not fully understood and novel therapeutic interventions require testing, there is a need for reliable animal models that mimic all the complications of diabetic retinopathy. Pig eyes share important anatomical and physiological similarities with human eyes. Previous studies have demonstrated that INS C94Y transgenic pigs develop a stable diabetic phenotype and ocular alterations such as cataracts. The aim of this study was to conduct an in-depth analysis of pathological changes in retinas from INS C94Y pigs exposed to hyperglycaemia for more than 2 years, representing a chronic diabetic condition. Eyes from six INS C94Ypigs and six age-matched control littermates were analysed via histology and immunohistochemistry. For histological analyses of retinal (layer) thickness, sections were stained with H&E or Mallory’s trichrome. For comparison of protein expression patterns and vessel courses, sections were stained with different antibodies in immunohistochemistry. Observed lesions were compared with reported pathologies in human diabetic retinopathy. INS C94Ypigs developed several signs of diabetic retinopathy similar to those seen in humans, such as Intraretinal Microvascular Abnormalities, symptoms of proliferative diabetic retinopathy and central retinal oedema in a region that is cone rich, like the human macula. The INS C94Ypig is an interesting model for studying the pathophysiology of diabetic retinopathy and for testing novel therapeutic strategies.
Ingolf H L Wallow - One of the best experts on this subject based on the ideXlab platform.
-
clinicopathologic correlation of Intraretinal Microvascular Abnormalities
Retina-the Journal of Retinal and Vitreous Diseases, 1997Co-Authors: Pascal D Imesch, Colleen D Bindley, Ingolf H L WallowAbstract:PURPOSE To define the cross-sectional morphology of Intraretinal Microvascular Abnormalities, which previously have been described only in terms of trypsin digestion. MATERIAL/METHODS Fourteen vascular lesions of five patients with diabetic retinopathy were identified on fundus photographs and/or fluorescein angiograms and classified as Intraretinal Microvascular Abnormalities. Eyes of these patients were obtained after the patients' deaths. The period between the time at which the photographs were taken and that at which enucleation was performed was 3-20 months. The duration of autolysis before fixation was 5 hours or less. The embedded tissue was evaluated by light and electron microscopy, and these findings were correlated with the clinical appearance. RESULTS The lesions consisted of multiple, closely spaced, thin-walled vascular lumina with a caliber of 20-70 microns. They were located in the inner retina and surrounded by a wide cuff containing randomly oriented collagen fibers. Endothelial cell nuclei were numerous. Pericyte degeneration and multiplication of the endothelial and pericyte basement membrane had occurred. Endothelial junctions were short, and gaping of junctions was not seen. However, occasional fenestrations were present. CONCLUSION The cross-sectional morphology of Intraretinal Microvascular Abnormalities is consistent with vascular pathology typical for Intraretinal diabetic microangiopathy, but also includes features usually seen in new vessels. This supports the concept that Intraretinal Microvascular Abnormalities have the particular potential for neovascularization.
Caroline R Baumal - One of the best experts on this subject based on the ideXlab platform.
-
distinguishing Intraretinal Microvascular Abnormalities from retinal neovascularization using optical coherence tomography angiography
Retina-the Journal of Retinal and Vitreous Diseases, 2020Co-Authors: Malvika Arya, Osama Sorour, Juhi Chaudhri, Yasin Alibhai, Nadia K Waheed, Jay S Duker, Caroline R BaumalAbstract:PURPOSE With the increasing prevalence of diabetes, fast, noninvasive identification of proliferative diabetic retinopathy (PDR) becomes essential. This study evaluated the utility of optical coherence tomography angiography (OCTA) to characterize Intraretinal Microvascular Abnormalities (IRMA) and retinal neovascularization (NV). METHODS Patients with severe non-PDR or PDR were imaged with fluorescein angiography and widefield swept-source OCTA (Zeiss Plex Elite 9000; Carl Zeiss Meditec, Dublin, CA). Regions suspicious for IRMA or retinal NV were identified and the OCTA, including flow overlay on the co-registered structural optical coherence tomography, and fluorescein angiography images were graded by two masked readers. RESULTS Ninety-six foci of irregular vasculature were analyzed, comprised of 70 IRMA and 26 retinal NV lesions from 14 eyes. Compared with fluorescein angiography, OCTA with flow overlay demonstrated specificity of 99% and sensitivity of 92% in identifying IRMA and NV. Neovascularization differed from IRMA on OCTA by demonstrating supraretinal flow breaching the internal limiting membrane and posterior hyaloid (P < 0.001). Intraretinal Microvascular Abnormalities were distinguished from NV by outpouching of the internal limiting membrane (P = 0.035). Vascular flow was reduced in the presence of fibrosis. CONCLUSION Optical coherence tomography angiography, through flow overlay, has utility to image and differentiate IRMA and NV, which are key features distinguishing severe non-PDR and PDR, respectively. Noninvasive widefield OCTA may be a useful tool to diagnose high-risk diabetic retinopathy eyes.
-
morphological changes in Intraretinal Microvascular Abnormalities after anti vegf therapy visualized on optical coherence tomography angiography
Eye and vision (London England), 2020Co-Authors: Osama Sorour, Caroline R Baumal, Akihiro Ishibazawa, Nihaal Mehta, Keke Liu, Eleni K KonstantinouAbstract:To examine the baseline morphological characteristics and alterations in Intraretinal Microvascular Abnormalities (IRMAs) in response to anti-vascular endothelial growth factor (anti-VEGF) treatment, documented by optical coherence tomography angiography (OCTA) in diabetic eyes. In this retrospective study, IRMAs were evaluated with multimodal imaging (fundus photography, fluorescein angiography, OCTA) in treatment-naive diabetic eyes before and after anti-VEGF treatment for diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR) and compared to diabetic control eyes with similar diabetic retinopathy (DR) severity that did not receive anti-VEGF therapy. The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline, then after anti-VEGF therapy in treated eyes or after observation in control eyes. Characterization of interval changes in an IRMA were based on the following parameters: branching, vessel caliber and area of adjacent capillary non-perfusion. The treated group included 45 IRMA foci from 15 eyes of 11 patients, while the control group included 27 IRMA foci from 15 eyes of 14 patients. Following anti-VEGF treatment, enface OCTA demonstrated that 14 foci of IRMA (31%) demonstrated regression with normalization of appearance of the capillary bed, 20 IRMAs (44%) remained unchanged, six IRMAs (13%) progressed with enlargement or development of new IRMAs and five IRMAs (11%) demonstrated complete obliteration defined as IRMA disappearance with advancing capillary drop-out. In the control group, 17 IRMA (63%) remained stable, 8 IRMAs (29.6%) progressed and 2 experienced total obliteration (7.4%). The difference in rank order between the two groups was statistically significant (p = 0.022). In eyes with DR status post anti-VEGF therapy, foci of IRMAs have a variable course demonstrating one of four possible outcomes: regression, stability, progression or complete obliteration. In contrast, none of the untreated control diabetic eyes demonstrated regression of IRMAs, consistent with known progression of DR severity in high risk eyes. Morphologic evaluation of IRMAs with OCTA may help to monitor changes in retinal blood flow as well as the response to anti-VEGF treatment.
-
evaluation of preretinal neovascularization in proliferative diabetic retinopathy using optical coherence tomography angiography
Ophthalmic Surgery and Lasers, 2016Co-Authors: Bonini Filho, Jay S Duker, Caroline R Baumal, Elias Reichel, Adam H Rogers, Andre J Witkin, Nadia K WaheedAbstract:BACKGROUND AND OBJECTIVE To describe a method for visualizing preretinal neovascularization in proliferative diabetic retinopathy (PDR) using optical coherence tomography angiography (OCTA) and report the findings in the surrounding vasculature. PATIENTS AND METHODS Patients with PDR diagnosed on clinical examination who received OCTA scans using the RTVue XR Avanti (Optovue, Fremont, CA) were evaluated. To visualize preretinal neovascularization, OCT angiograms were segmented to project vasculature above the internal limiting membrane (ILM). OCT angiograms were segmented between the ILM and Bruch's membrane to show adjacent retinal vasculature. RESULTS Thirteen eyes were determined to have preretinal neovascularization in the posterior pole based on OCTA. One OCT angiogram was not of sufficient quality and thus was eliminated from further study. Eleven eyes (92%) had neovascularization adjacent to retinal capillary nonperfusion and six (50%) were adjacent to Intraretinal Microvascular Abnormalities (IRMAs). CONCLUSION OCTA provided high-resolution, depth-resolved blood flow information, allowing for visualization of preretinal neovascularization, IRMA, and adjacent capillary nonperfusion.
Osama Sorour - One of the best experts on this subject based on the ideXlab platform.
-
distinguishing Intraretinal Microvascular Abnormalities from retinal neovascularization using optical coherence tomography angiography
Retina-the Journal of Retinal and Vitreous Diseases, 2020Co-Authors: Malvika Arya, Osama Sorour, Juhi Chaudhri, Yasin Alibhai, Nadia K Waheed, Jay S Duker, Caroline R BaumalAbstract:PURPOSE With the increasing prevalence of diabetes, fast, noninvasive identification of proliferative diabetic retinopathy (PDR) becomes essential. This study evaluated the utility of optical coherence tomography angiography (OCTA) to characterize Intraretinal Microvascular Abnormalities (IRMA) and retinal neovascularization (NV). METHODS Patients with severe non-PDR or PDR were imaged with fluorescein angiography and widefield swept-source OCTA (Zeiss Plex Elite 9000; Carl Zeiss Meditec, Dublin, CA). Regions suspicious for IRMA or retinal NV were identified and the OCTA, including flow overlay on the co-registered structural optical coherence tomography, and fluorescein angiography images were graded by two masked readers. RESULTS Ninety-six foci of irregular vasculature were analyzed, comprised of 70 IRMA and 26 retinal NV lesions from 14 eyes. Compared with fluorescein angiography, OCTA with flow overlay demonstrated specificity of 99% and sensitivity of 92% in identifying IRMA and NV. Neovascularization differed from IRMA on OCTA by demonstrating supraretinal flow breaching the internal limiting membrane and posterior hyaloid (P < 0.001). Intraretinal Microvascular Abnormalities were distinguished from NV by outpouching of the internal limiting membrane (P = 0.035). Vascular flow was reduced in the presence of fibrosis. CONCLUSION Optical coherence tomography angiography, through flow overlay, has utility to image and differentiate IRMA and NV, which are key features distinguishing severe non-PDR and PDR, respectively. Noninvasive widefield OCTA may be a useful tool to diagnose high-risk diabetic retinopathy eyes.
-
morphological changes in Intraretinal Microvascular Abnormalities after anti vegf therapy visualized on optical coherence tomography angiography
Eye and vision (London England), 2020Co-Authors: Osama Sorour, Caroline R Baumal, Akihiro Ishibazawa, Nihaal Mehta, Keke Liu, Eleni K KonstantinouAbstract:To examine the baseline morphological characteristics and alterations in Intraretinal Microvascular Abnormalities (IRMAs) in response to anti-vascular endothelial growth factor (anti-VEGF) treatment, documented by optical coherence tomography angiography (OCTA) in diabetic eyes. In this retrospective study, IRMAs were evaluated with multimodal imaging (fundus photography, fluorescein angiography, OCTA) in treatment-naive diabetic eyes before and after anti-VEGF treatment for diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR) and compared to diabetic control eyes with similar diabetic retinopathy (DR) severity that did not receive anti-VEGF therapy. The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline, then after anti-VEGF therapy in treated eyes or after observation in control eyes. Characterization of interval changes in an IRMA were based on the following parameters: branching, vessel caliber and area of adjacent capillary non-perfusion. The treated group included 45 IRMA foci from 15 eyes of 11 patients, while the control group included 27 IRMA foci from 15 eyes of 14 patients. Following anti-VEGF treatment, enface OCTA demonstrated that 14 foci of IRMA (31%) demonstrated regression with normalization of appearance of the capillary bed, 20 IRMAs (44%) remained unchanged, six IRMAs (13%) progressed with enlargement or development of new IRMAs and five IRMAs (11%) demonstrated complete obliteration defined as IRMA disappearance with advancing capillary drop-out. In the control group, 17 IRMA (63%) remained stable, 8 IRMAs (29.6%) progressed and 2 experienced total obliteration (7.4%). The difference in rank order between the two groups was statistically significant (p = 0.022). In eyes with DR status post anti-VEGF therapy, foci of IRMAs have a variable course demonstrating one of four possible outcomes: regression, stability, progression or complete obliteration. In contrast, none of the untreated control diabetic eyes demonstrated regression of IRMAs, consistent with known progression of DR severity in high risk eyes. Morphologic evaluation of IRMAs with OCTA may help to monitor changes in retinal blood flow as well as the response to anti-VEGF treatment.
Akitoshi Yoshida - One of the best experts on this subject based on the ideXlab platform.
-
a proposed classification of Intraretinal Microvascular Abnormalities in diabetic retinopathy following panretinal photocoagulation
Investigative Ophthalmology & Visual Science, 2020Co-Authors: Akito Shimouchi, Akihiro Ishibazawa, Satoshi Ishiko, Tsuneaki Omae, Tomoko Romase, Yasuo Yanagi, Akitoshi YoshidaAbstract:Purpose To investigate the characteristics of Intraretinal Microvascular Abnormalities (IRMAs) before and after panretinal photocoagulation (PRP) for diabetic retinopathy (DR) by using optical coherence tomography angiography (OCTA). Methods Forty-six eyes of 29 patients with DR were included (26 eyes with severe nonproliferative diabetic retinopathy [SNPDR] and 20 eyes with proliferative diabetic retinopathy [PDR]). En face OCTA images of IRMAs in a 6 × 6-mm area were acquired by using Cirrus 5000 with AngioPlex. The morphological changes in IRMAs were evaluated before and after PRP. The changes in the IRMAs were divided into five subtypes: unchanged; tuft regression; reperfusion; mixed (combined tuft regression/reperfusion); and worsening (new appearance of tuft). Results Unchanged IRMAs were identified in 15 SNPDR eyes and 2 PDR eyes; all neovascularization (NV) had regressed after PRP. Tufts were more frequently observed in the PDR eyes (15/20, 75%) than in the SNPDR eyes (8/26, 31%) (P = 0.003), and two tufts tended to exceed the inner limiting membrane, which showed progression to NV before PRP. The reperfusion phenomenon was observed in 7/26 SNPDR eyes and 4/20 PDR eyes, including the mixed type, and showed two vascular patterns: abnormal (dilated, tortuous, and twisted) and normal vessels. The worsening type was observed in 1/26 SNPDR eye and 2/20 PDR eyes. Conclusions OCTA enabled classification of IRMA into more detailed types. The unchanged and reperfusion types suggested that IRMAs had aspects of remodeling. However, IRMAs with tufts were observed in 75% of the PDR eyes, and the tufts had aspects of NV.