1
|
Böhm EW, Pfeiffer N, Wagner FM, Gericke A. Methods to measure blood flow and vascular reactivity in the retina. Front Med (Lausanne) 2023; 9:1069449. [PMID: 36714119 PMCID: PMC9877427 DOI: 10.3389/fmed.2022.1069449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 12/23/2022] [Indexed: 01/14/2023] Open
Abstract
Disturbances of retinal perfusion are involved in the onset and maintenance of several ocular diseases, including diabetic retinopathy, glaucoma, and retinal vascular occlusion. Hence, knowledge on ocular vascular anatomy and function is highly relevant for basic research studies and for clinical judgment and treatment. The retinal vasculature is composed of the superficial, intermediate, and deep vascular layer. Detection of changes in blood flow and vascular diameter especially in smaller vessels is essential to understand and to analyze vascular diseases. Several methods to evaluate blood flow regulation in the retina have been described so far, but no gold standard has been established. For highly reliable assessment of retinal blood flow, exact determination of vessel diameter is necessary. Several measurement methods have already been reported in humans. But for further analysis of retinal vascular diseases, studies in laboratory animals, including genetically modified mice, are important. As for mice, the small vessel size is challenging requiring devices with high optic resolution. In this review, we recapitulate different methods for retinal blood flow and vessel diameter measurement. Moreover, studies in humans and in experimental animals are described.
Collapse
|
2
|
Dholakia KY, Guevara-Torres A, Feng G, Power D, Schallek J. In Vivo Capillary Structure and Blood Cell Flux in the Normal and Diabetic Mouse Eye. Invest Ophthalmol Vis Sci 2022; 63:18. [PMID: 35138346 PMCID: PMC8842443 DOI: 10.1167/iovs.63.2.18] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Purpose To characterize the early structural and functional changes in the retinal microvasculature in response to hyperglycemia in the Ins2Akita mouse. Methods A custom phase-contrast adaptive optics scanning light ophthalmoscope was used to image retinal capillaries of 9 Ins2Akita positive (hyperglycemic) and 9 Ins2Akita negative (euglycemic) mice from postnatal weeks 5 to 18. A 15 kHz point scan was used to image capillaries and measure red blood cell flux at biweekly intervals; measurements were performed manually. Retinal thickness and fundus photos were captured monthly using a commercial scanning laser ophthalmoscope/optical coherence tomography. Retinal thickness was calculated using a custom algorithm. Blood glucose and weight were tracked throughout the duration of the study. Results Elevated blood glucose (>250 mg/dL) was observed at 4 to 5 weeks of age in Ins2Akita mice and remained elevated throughout the study, whereas euglycemic littermates maintained normal glucose levels. There was no significant difference in red blood cell flux, capillary anatomy, lumen diameter, or occurrence of stalled capillaries between hyperglycemic and euglycemic mice between postnatal weeks 5 and 18. Hyperglycemic mice had a thinner retina than euglycemic littermates (p < 0.001), but retinal thickness did not change with duration of hyperglycemia despite glucose levels that were more than twice times normal. Conclusions In early stages of hyperglycemia, retinal microvasculature structure (lumen diameter, capillary anatomy) and function (red blood cell flux, capillary perfusion) were not impaired despite 3 months of chronically elevated blood glucose. These findings suggest that hyperglycemia alone for 3 months does not alter capillary structure or function in profoundly hyperglycemic mice.
Collapse
Affiliation(s)
- Kosha Y Dholakia
- Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States.,Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Andres Guevara-Torres
- Center for Visual Science, University of Rochester, Rochester, New York, United States.,The Institute of Optics, University of Rochester, Rochester, New York, United States
| | - Guanping Feng
- Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States.,Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Derek Power
- Center for Visual Science, University of Rochester, Rochester, New York, United States.,Flaum Eye Institute, University of Rochester, Rochester, New York, United States
| | - Jesse Schallek
- Center for Visual Science, University of Rochester, Rochester, New York, United States.,Flaum Eye Institute, University of Rochester, Rochester, New York, United States.,Department of Neuroscience, University of Rochester, Rochester, New York, United States
| |
Collapse
|
3
|
Liu G, Wu F, Wu H, Wang Y, Jiang X, Hu P, Tong X. Inactivation of cysteine 674 in the sarcoplasmic/endoplasmic reticulum calcium ATPase 2 causes retinopathy in the mouse. Exp Eye Res 2021; 207:108559. [PMID: 33848522 DOI: 10.1016/j.exer.2021.108559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/01/2021] [Accepted: 03/23/2021] [Indexed: 12/12/2022]
Abstract
Diabetic retinopathy is a multifactorial microvascular complication, and its pathogenesis hasn't been fully elucidated. The irreversible oxidation of cysteine 674 (C674) in the sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) was increased in the type 1 diabetic retinal vasculature. SERCA2 C674S knock-in (SKI) mouse line that half of C674 was replaced by serine 674 (S674) was used to study the effect of C674 inactivation on retinopathy. Compared with wild type (WT) mice, SKI mice had increased number of acellular capillaries and pericyte loss similar to those in type 1 diabetic WT mice. In the retina of SKI mice, pro-apoptotic proteins and intracellular Ca2+-dependent signaling pathways increased, while anti-apoptotic proteins and vessel density decreased. In endothelial cells, C674 inactivation increased the expression of pro-apoptotic proteins, damaged mitochondria, and induced cell apoptosis. These results suggest that a possible mechanism of retinopathy induced by type 1 diabetes is the interruption of calcium homeostasis in the retina by oxidation of C674. C674 is a key to maintain retinal health. Its inactivation can cause retinopathy similar to type 1 diabetes by promoting apoptosis. SERCA2 might be a potential target for the prevention and treatment of diabetic retinopathy.
Collapse
Affiliation(s)
- Gang Liu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China; Henan Key Laboratory of Medical Tissue Regeneration, College of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan, 453003, China
| | - Fuhua Wu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Haixia Wu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Yaping Wang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Xiaoli Jiang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China
| | - Pingping Hu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China.
| | - Xiaoyong Tong
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, 401331, China.
| |
Collapse
|
4
|
Optical coherence tomography angiography in diabetic retinopathy: an updated review. Eye (Lond) 2020; 35:149-161. [PMID: 33099579 DOI: 10.1038/s41433-020-01233-y] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/27/2020] [Accepted: 10/15/2020] [Indexed: 12/17/2022] Open
Abstract
Diabetic retinopathy (DR) is a common microvascular complication of diabetes mellitus. Optical coherence tomography angiography (OCTA) has been developed to visualize the retinal microvasculature and choriocapillaris based on the motion contrast of circulating blood cells. Depth-resolved ability and non-invasive nature of OCTA allow for repeated examinations and visualization of microvasculature at the retinal capillary plexuses and choriocapillaris. OCTA enables quantification of microvascular alterations in the retinal capillary network, in addition to the detection of classical features associated with DR, including microaneurysms, intraretinal microvascular abnormalities, and neovascularization. OCTA has a promising role as an objective tool for quantifying extent of microvascular damage and identify eyes with diabetic macular ischaemia contributed to visual loss. Furthermore, OCTA can identify preclinical microvascular abnormalities preceding the onset of clinically detectable DR. In this review, we focused on the applications of OCTA derived quantitative metrics that are relevant to early detection, staging and progression of DR. Advancement of OCTA technology in clinical research will ultimately lead to enhancement of individualised management of DR and prevention of visual impairment in patients with diabetes.
Collapse
|
5
|
Meyer JH, Marx J, Strack C, Holz FG, Schmitz-Valckenberg S. Imaging of Therapeutic Effects of Anti-Vascular Endothelial Growth Factor Inhibitors by Optical Coherence Tomography Angiography in a Rat Model. Transl Vis Sci Technol 2020; 9:29. [PMID: 32832234 PMCID: PMC7414645 DOI: 10.1167/tvst.9.7.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/24/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose The aim of the study was to investigate optical coherence tomography angiography (OCTA) as a high-resolution in vivo imaging modality for monitoring therapeutic response to different vascular endothelial growth factor inhibitors in the rat model of laser-induced choroidal neovascularization (CNV). Further, OCTA findings were compared with fluorescein angiography (FA) and fluorescence microscopy. Methods Laser treatment at day (D)0 was followed by intravitreal injection of aflibercept, AF564, and NaCl in dark agouti rats. Imaging with OCTA and FA was performed at D2, D7, D14, and D21. OCTA was compared to FA as well as confocal imaged flat mounts and analysis included quantification of CNV area, pixel intensity, vessel density, and number of vessel junctions. Results Within laser lesions, neovascularization were visible especially in deeper retinal layers on OCTA, but not on FA images. Using OCTA, mean CNV area (D21) at the level of the outer nuclear layer (ONL) was 0.017 mm² following aflibercept administration, 0.016 mm² following AF564 and 0.026 mm² following NaCl injection (P = 0.04 and P = 0.03). Similar differences between treatment groups were determined by FA and histology, although the overall CNV area was always larger on FA due to dye leakage (P ≤ 0.0001, all layers). Conclusions Compared to FA, OCTA imaging allows for a more precise and quantitative analysis of new blood vessel formation and therapeutic response to vascular endothelial growth factor (VEGF)-inhibitors, whereas it does not permit assessment of leakage. Translational Relevance These findings suggest that OCTA may be particularly useful for the investigation of new treatment targets in the animal model.
Collapse
Affiliation(s)
- Johanna H Meyer
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Janine Marx
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Claudine Strack
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Steffen Schmitz-Valckenberg
- Department of Ophthalmology, University of Bonn, Bonn, Germany.,John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| |
Collapse
|
6
|
Carroll LS, Uehara H, Fang D, Choi S, Zhang X, Singh M, Sandhu Z, Cummins PM, Curtis TM, Stitt AW, Archer BJ, Ambati BK. Intravitreal AAV2.COMP-Ang1 Attenuates Deep Capillary Plexus Expansion in the Aged Diabetic Mouse Retina. Invest Ophthalmol Vis Sci 2019; 60:2494-2502. [PMID: 31185088 PMCID: PMC6559753 DOI: 10.1167/iovs.18-26182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We determine whether intravitreal angiopoietin-1 combined with the short coiled-coil domain of cartilage oligomeric matrix protein by adeno-associated viral serotype 2 (AAV2.COMP-Ang1) delivery following the onset of vascular damage could rescue or repair damaged vascular beds and attenuate neuronal atrophy and dysfunction in the retinas of aged diabetic mice. Methods AAV2.COMP-Ang1 was bilaterally injected into the vitreous of 6-month-old male Ins2Akita mice. Age-matched controls consisted of uninjected C57BL/6J and Ins2Akita males, and of Ins2Akita males injected with PBS or AAV2.REPORTER (AcGFP or LacZ). Retinal thickness and visual acuity were measured in vivo at baseline and at the 10.5-month endpoint. Ex vivo vascular parameters were measured from retinal flat mounts, and Western blot was used to detect protein expression. Results All three Ins2Akita control groups showed significantly increased deep vascular density at 10.5 months compared to uninjected C57BL/6J retinas (as measured by vessel area, length, lacunarity, and number of junctions). In contrast, deep microvascular density of Ins2Akita retinas treated with AAV2.COMP-Ang1 was more similar to uninjected C57BL/6J retinas for all parameters. However, no significant improvement in retinal thinning or diabetic retinopathy-associated visual loss was found in treated diabetic retinas. Conclusions Deep retinal microvasculature of diabetic Ins2Akita eyes shows late stage changes consistent with disorganized vascular proliferation. We show that intravitreally injected AAV2.COMP-Ang1 blocks this increase in deep microvascularity, even when administered subsequent to development of the first detectable vascular defects. However, improving vascular normalization did not attenuate neuroretinal degeneration or loss of visual acuity. Therefore, additional interventions are required to address neurodegenerative changes that are already underway.
Collapse
Affiliation(s)
- Lara S Carroll
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Hironori Uehara
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Daniel Fang
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Susie Choi
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Xiaohui Zhang
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Malkit Singh
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Zoya Sandhu
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Philip M Cummins
- School of Biotechnology, Dublin City University, Glasnevin, Dublin, Ireland
| | - Tim M Curtis
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, United Kingdom
| | - Alan W Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, United Kingdom
| | - Bonnie J Archer
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Balamurali K Ambati
- Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| |
Collapse
|
7
|
Smith CA, Hooper ML, Chauhan BC. Optical Coherence Tomography Angiography in Mice: Quantitative Analysis After Experimental Models of Retinal Damage. Invest Ophthalmol Vis Sci 2019; 60:1556-1565. [PMID: 30995294 DOI: 10.1167/iovs.18-26441] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We implemented optical coherence tomography angiography (OCT-A) in mice to: (1) develop quantitative parameters from OCT-A images, (2) measure the reproducibility of the parameters, and (3) determine the impact of experimental models of inner and outer retinal damage on OCT-A findings. Methods OCT-A images were acquired with a customized system (Spectralis Multiline OCT2). To assess reproducibility, imaging was performed five times over 1 month. Inner retinal damage was induced with optic nerve transection, crush, or intravitreal N-methyl-d-aspartic acid injection in transgenic mice with fluorescently labeled retinal ganglion cells (RGCs). Light-induced retinal damage was induced in albino mice. Mice were imaged at baseline and serially post injury. Perfusion density, vessel length, and branch points were computed from OCT-A images of the superficial, intermediate, and deep vascular plexuses. Results The range of relative differences measured between sessions across the vascular plexuses were: perfusion density (2.8%-7.0%), vessel length (1.9%-4.1%), and branch points (1.9%-5.0%). In mice with progressive RGC loss, imaged serially and culminating in around 70% loss in the fluorescence signal and 18% loss in inner retinal thickness, there were no measurable changes in any OCT-A parameter up to 4 months post injury that exceeded measurement variability. However, light-induced retinal damage elicited a progressive loss of the deep vascular plexus signal, starting as early as 3 days post injury. Conclusions Vessel length and branch points were generally the most reproducible among the parameters. Injury causing RGC loss in mice did not elicit an early change in the OCT-A signal.
Collapse
Affiliation(s)
- Corey A Smith
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.,Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michele L Hooper
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Balwantray C Chauhan
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.,Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| |
Collapse
|
8
|
Han Y, Shang Q, Yao J, Ji Y. Hydrogen sulfide: a gaseous signaling molecule modulates tissue homeostasis: implications in ophthalmic diseases. Cell Death Dis 2019; 10:293. [PMID: 30926772 PMCID: PMC6441042 DOI: 10.1038/s41419-019-1525-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 02/12/2019] [Accepted: 03/11/2019] [Indexed: 12/14/2022]
Abstract
Hydrogen sulfide (H2S) serves as a gasotransmitter in the regulation of organ development and maintenance of homeostasis in tissues. Its abnormal levels are associated with multiple human diseases, such as neurodegenerative disease, myocardial injury, and ophthalmic diseases. Excessive exposure to H2S could lead to cellular toxicity, orchestrate pathological process, and increase the risk of various diseases. Interestingly, under physiological status, H2S plays a critical role in maintaining cellular physiology and limiting damages to tissues. In mammalian species, the generation of H2S is catalyzed by cystathionine beta-synthase (CBS), cystathionine gamma-lyase (CSE), 3-mercapto-methylthio pyruvate aminotransferase (3MST) and cysteine aminotransferase (CAT). These enzymes are found inside the mammalian eyeballs at different locations. Their aberrant expression and the accumulation of substrates and intermediates can change the level of H2S by orders of magnitude, causing abnormal structures or functions in the eyes. Detailed investigations have demonstrated that H2S donors' administration could regulate intraocular pressure, protect retinal cells, inhibit oxidative stress and alleviate inflammation by modulating the function of intra or extracellular proteins in ocular tissues. Thus, several slow-releasing H2S donors have been shown to be promising drugs for treating multiple diseases. In this review, we discuss the biological function of H2S metabolism and its application in ophthalmic diseases.
Collapse
Affiliation(s)
- Yuyi Han
- Department of Ophthalmology, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, China
| | - Qianwen Shang
- Institutes for Translational Medicine, Soochow University Medical College, Suzhou, China
| | - Jin Yao
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing, China.
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing, China.
| | - Yong Ji
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, China.
| |
Collapse
|