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Wei J, Chen C, Shen Y, Li F, Yiyang S, Liu H. Quantitative evaluation of ocular vascularity and correlation analysis in patients with diabetic retinopathy by SMI and OCTA. BMC Ophthalmol 2024; 24:76. [PMID: 38373920 PMCID: PMC10875800 DOI: 10.1186/s12886-024-03338-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/02/2024] [Indexed: 02/21/2024] Open
Abstract
AIMS To find potential relation between retrobulbar vessels and fundus microvessels and to detect sensitive and effective clinical indicators in predicting the progress of diabetic retinopathy (DR), ocular hemodynamics were measured using superb microvascular imaging (SMI) and ultrawide-field optical coherence tomography angiography (UWF-OCTA). METHODS Observational, cross-sectional study evaluating ocular hemodynamics in patients with DR by SMI (Aplio i900, Canon Medical) and UWF-OCTA (BM-400 K BMizar, Tupai Medical Technology). The peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) of the central retinal artery (CRA), posterior ciliary artery (PCA), and ophthalmic artery (OA) were measured by SMI. UWF-OCTA evaluated the fundus vascular parameters. A correlation analysis was used to determine the correlation between SMI and UWF-OCTA parameters. RESULTS One hundred thirty-nine eyes of 139 diabetic patients were included: 29 without DR (NDR), 36 with mild to moderate nonproliferative DR (M-NPDR), 37 with severe NPDR (S-NPDR), and 37 with proliferative DR (PDR). PSV and EDV of retrobulbar vessels decreased from NDR to S-NPDR while increasing PDR. RI of OA showed a decreasing trend in the progression of DR, but other vessels didn't show the same trend. ROC curve analysis showed that CRAPSV, CRAEDV, PCAEDV, OAPSV, and OAEDV had diagnostic value distinguishing M-NPDR and S-NPDR. The correlation analysis observed a significant association between the SMI parameters of CRA and PCA and UWF-OCTA parameters. CRA hemodynamics were more associated with fundus vascular parameters, especially the retina, in the NDR group than in the M-NPDR group. In contrast, PCA consistently correlated with fundus vascular parameters, especially in the choroid, from the NDR to the M-NPDR group. However, OA showed a poor correlation with OCTA parameters. CONCLUSION The velocity of retrobulbar vessels, mainly the CRA, may serve as a valuable predictor for assessing the progress of DR. The use of SMI in diabetic patients may help identify patients at risk of developing retinopathy.
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Affiliation(s)
- Jin Wei
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 20080, China
- National Clinical Research Center for Eye Diseases, Shanghai, 20080, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, 20080, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, 20080, China
- Shanghai engineering center for precise diagnosis and treatment of eye diseases, Shanghai, 20080, China
| | - Chong Chen
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 20080, China
- National Clinical Research Center for Eye Diseases, Shanghai, 20080, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, 20080, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, 20080, China
- Shanghai engineering center for precise diagnosis and treatment of eye diseases, Shanghai, 20080, China
| | - Yinchen Shen
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 20080, China
- National Clinical Research Center for Eye Diseases, Shanghai, 20080, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, 20080, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, 20080, China
- Shanghai engineering center for precise diagnosis and treatment of eye diseases, Shanghai, 20080, China
| | - Fang Li
- Department of Ultrasound, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 20080, China
| | - Shu Yiyang
- Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065, China
| | - Haiyun Liu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 20080, China.
- National Clinical Research Center for Eye Diseases, Shanghai, 20080, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, 20080, China.
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, 20080, China.
- Shanghai engineering center for precise diagnosis and treatment of eye diseases, Shanghai, 20080, China.
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Yasuda K, Noma H, Mimura T, Nonaka R, Sasaki S, Suganuma N, Shimura M. Effects of Intravitreal Ranibizumab Injection on Peripheral Retinal Microcirculation and Cytokines in Branch Retinal Vein Occlusion with Macular Edema. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1053. [PMID: 37374257 DOI: 10.3390/medicina59061053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/26/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023]
Abstract
Background and Objectives: To investigate peripheral blood flow in retinal vessels and vessel diameters after intravitreal ranibizumab injection (IRI) and the relationship between these parameters and cytokines in branch retinal vein occlusion (BRVO) with macular edema. Materials and Methods: We assessed relative flow volume (RFV) and the width of the main and branch retinal arteries and veins in the occluded and non-occluded regions before and after IRI in 37 patients with BRVO and macular edema. Measurements were made using laser speckle flowgraphy (LSFG). When performing IRI, we obtained samples of aqueous humor and analyzed them using the suspension array method to evaluate vascular endothelial growth factor (VEGF), placental growth factor (PlGF), platelet-derived growth factor (PDGF)-AA, soluble intercellular adhesion molecule (sICAM)-1, monocyte chemoattractant protein 1 (MCP-1), interleukin (IL)-6, IL-8, and interferon-inducible 10-kDa protein (IP-10). Results: In both retinal regions, before and after IRI, the RFV in the main artery and vein showed a significant correlation with the summed RFV in the respective branch vessels 1 and 2. In the occluded region, the RFV in the main vein was significantly negatively correlated with MCP-1, PDGF-AA, IL-6, and IL-8; the RFV in branch vein 1 was significantly negatively correlated with PlGF, MCP-1, IL-6, and IL-8; PDGF-AA was significantly negatively correlated with the width of the main and branch veins; and the RFVs of the main artery and vein decreased significantly from before to 1 month after IRI. Conclusions: Contrary to expectations, the study found that anti-VEGF therapy does not affect RFV in arteries and veins in patients with BRVO and macular edema. Furthermore, retinal blood flow is poor in patients with high MCP-1, IL-6, and IL-8. Finally, high PDGF-AA may result in smaller venous diameters and reduced retinal blood flow.
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Affiliation(s)
- Kanako Yasuda
- Department of Ophthalmology, Hachioji Medical Center, Tokyo Medical University, 1163, Tatemachi, Hachioji, Tokyo 193-0998, Japan
| | - Hidetaka Noma
- Department of Ophthalmology, Hachioji Medical Center, Tokyo Medical University, 1163, Tatemachi, Hachioji, Tokyo 193-0998, Japan
| | - Tatsuya Mimura
- Department of Ophthalmology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8606, Japan
| | - Ryota Nonaka
- Department of Ophthalmology, Hachioji Medical Center, Tokyo Medical University, 1163, Tatemachi, Hachioji, Tokyo 193-0998, Japan
| | - Shotaro Sasaki
- Department of Ophthalmology, Hachioji Medical Center, Tokyo Medical University, 1163, Tatemachi, Hachioji, Tokyo 193-0998, Japan
| | - Noboru Suganuma
- Department of Ophthalmology, Hachioji Medical Center, Tokyo Medical University, 1163, Tatemachi, Hachioji, Tokyo 193-0998, Japan
| | - Masahiko Shimura
- Department of Ophthalmology, Hachioji Medical Center, Tokyo Medical University, 1163, Tatemachi, Hachioji, Tokyo 193-0998, Japan
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Mohite AA, Perais JA, McCullough P, Lois N. Retinal Ischaemia in Diabetic Retinopathy: Understanding and Overcoming a Therapeutic Challenge. J Clin Med 2023; 12:jcm12062406. [PMID: 36983406 PMCID: PMC10056455 DOI: 10.3390/jcm12062406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/07/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
BACKGROUND Retinal ischaemia is present to a greater or lesser extent in all eyes with diabetic retinopathy (DR). Nonetheless, our understanding of its pathogenic mechanisms, risk factors, as well as other characteristics of retinal ischaemia in DR is very limited. To date, there is no treatment to revascularise ischaemic retina. METHODS Review of the literature highlighting the current knowledge on the topic of retinal ischaemia in DR, important observations made, and underlying gaps for which research is needed. RESULTS A very scarce number of clinical studies, mostly cross-sectional, have evaluated specifically retinal ischaemia in DR. Interindividual variability on its natural course and consequences, including the development of its major complications, namely diabetic macular ischaemia and proliferative diabetic retinopathy, have not been investigated. The in situ, surrounding, and distance effect of retinal ischaemia on retinal function and structure and its change over time remains also to be elucidated. Treatments to prevent the development of retinal ischaemia and, importantly, to achieve retinal reperfusion once capillary drop out has ensued, are very much needed and remain to be developed. CONCLUSION Research into retinal ischaemia in diabetes should be a priority to save sight.
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Affiliation(s)
- Ajay A Mohite
- Department of Ophthalmology, Belfast Health and Social Care Trust, Belfast BT12 6BA, UK
| | - Jennifer A Perais
- Welcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Philip McCullough
- Welcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Noemi Lois
- Department of Ophthalmology, Belfast Health and Social Care Trust, Belfast BT12 6BA, UK
- Welcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
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Noh M, Kim Y, Zhang H, Kim H, Bae CR, Lee S, Kwon YG. Oral administration of CU06-1004 attenuates vascular permeability and stabilizes neovascularization in retinal vascular diseases. Eur J Pharmacol 2023; 939:175427. [PMID: 36509133 DOI: 10.1016/j.ejphar.2022.175427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022]
Abstract
Retinal vascular diseases are the leading cause of blindness worldwide. These diseases have common disease mechanisms including vascular endothelial growth factor (VEGF) signaling, hypoxia, and inflammation. Treatment of these diseases with laser therapy, anti-VEGF injections and/or steroids has significantly improved clinical outcomes. However, these strategies do not address the underlying cause of the pathology and may have harmful side effects. Pathological processes that damage retinal vessels result in vascular occlusion and impairment of the barrier properties of retinal endothelial cells, leading to excessive vascular leakage. Therefore, a new therapeutic approach is needed for the treatment of retinal vascular disease. We were able to confirm that oral administration of CU06-1004, an endothelial dysfunction blocker, inhibited retinal vascular leakage induced by vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang2). Interestingly, oral administration of CU06-1004 prevented excessive vascular leakage in the diabetic retinopathy model. In addition, CU06-1004 inhibited angiogenesis and confirmed vascular stabilization in the oxygen-induced retinopathy model and laser-induced CNV model. Taken together, CU06-1004 could be a potential therapeutic agent for the treatment of retinal vascular diseases.
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Affiliation(s)
- Minyoung Noh
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Yeomyeong Kim
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Haiying Zhang
- R&D Department, Curacle Co. Ltd, Seoul, 06694, Republic of Korea
| | - Hyejeong Kim
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Cho-Rong Bae
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Sunghye Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Young-Guen Kwon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea.
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Şimşek S, İşlek A. Diagnostic and predictive value of resistive / pulsatility indices of ophthalmic artery and common carotid artery for the development of diabetic retinopathy. Acta Radiol 2022; 64:1966-1973. [PMID: 36377226 DOI: 10.1177/02841851221137766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Ophthalmic artery resistive index (OA RI) was a controversial parameter to show hemodynamic changes due to diabetic retinopathy (DRP). Purpose To investigate the diagnostic and predictive value of resistive and pulsatility index (RI and PI, respectively) of OA and common carotid artery (CCA) for the development of DRP. Material and Methods A total of 60 patients with diabetes mellitus (DM) type 2 (study group) and 30 healthy participants (control group) were evaluated between January and June 2021 by Doppler ultrasonography (DUS). RI and PI values were compared between groups with a Student’s t-test. Cutoff value, sensitivity, and specificity were calculated for the significant variables with receiver operating characteristic (ROC) analysis. Results In total, there were 20 (22.2%) patients with DM without DRP (DMwoRP), 20 (22.2%) patients in the non-proliferative diabetic retinopathy group (NPDRP), and 20 (22.2%) patients in the proliferative diabetic retinopathy group (PDRP). The mean of CCA RI and OA RI in the PDRP group was significantly higher than in the other three groups ( P < 0.001). The mean of CCA RI and OA RI was significantly higher in the PDRP group than in the NPDRP group, and in the NPDRP group compared to the DMwoRP group. CCA RI and OA RI showed a significantly high correlation (r = 0.849; P < 0.001). Sensitivity was 95% and specificity was 100% for the diagnosis of PDRP for the 0.82 cutoff value of OA RI (AUR = 0.999, 95% confidence interval for AUC = 0.997–0.1000; P < 0.001). Conclusion The OA RI accurately reflects DRP-induced orbital blood flow changes and is a predictive index for DRP prognosis.
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Affiliation(s)
- Sadullah Şimşek
- Department of Radiology, Dicle University, Diyarbakır, Turkey
| | - Akif İşlek
- Otolaryngology-Head & Neck Surgery Clinic, Acıbadem Eskişehir Hospital, Eskişehir, Turkey
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Eshaq RS, Watts MN, Carter PR, Leskova W, Aw TY, Alexander JS, Harris NR. Candesartan Normalizes Changes in Retinal Blood Flow and p22phox in the Diabetic Rat Retina. PATHOPHYSIOLOGY 2021; 28:86-97. [PMID: 35366272 PMCID: PMC8830460 DOI: 10.3390/pathophysiology28010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 11/23/2022] Open
Abstract
Angiotensin II has been implicated in the progression of diabetic retinopathy, which is characterized by altered microvasculature, oxidative stress, and neuronal dysfunction. The signaling induced by angiotensin II can occur not only via receptor-mediated calcium release that causes vascular constriction, but also through a pathway whereby angiotensin II activates NADPH oxidase to elicit the formation of reactive oxygen species (ROS). In the current study, we administered the angiotensin II receptor antagonist candesartan (or vehicle, in untreated animals) in a rat model of type 1 diabetes in which hyperglycemia was induced by injection of streptozotocin (STZ). Eight weeks after the STZ injection, untreated diabetic rats were found to have a significant increase in tissue levels of angiotensin converting enzyme (ACE; p < 0.05) compared to non-diabetic controls, a 33% decrease in retinal blood flow rate (p < 0.001), and a dramatic increase in p22phox (a subunit of the NADPH oxidase). The decrease in retinal blood flow, and the increases in retinal ACE and p22phox in the diabetic rats, were all significantly attenuated (p < 0.05) by the administration of candesartan in drinking water within one week. Neither STZ nor candesartan induced any changes in tissue levels of superoxide dismutase (SOD-1), 4-hydroxynonenal (4-HNE), or nitrotyrosine. We conclude that one additional benefit of candesartan (and other angiotensin II antagonists) may be to normalize retinal blood flow, which may have clinical benefits in diabetic retinopathy.
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Association of changes of retinal vessels diameter with ocular blood flow in eyes with diabetic retinopathy. Sci Rep 2021; 11:4653. [PMID: 33633255 PMCID: PMC7907275 DOI: 10.1038/s41598-021-84067-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/09/2021] [Indexed: 12/25/2022] Open
Abstract
We investigated morphological changes of retinal arteries to determine their association with the blood flow and systemic variables in type 2 diabetes patients. The patients included 47 non-diabetic retinopathy eyes, 36 mild or moderate nonproliferative diabetic retinopathy (M-NPDR) eyes, 22 severe NPDR (S-NPDR) eyes, 32 PDR eyes, and 24 normal eyes as controls. The mean wall to lumen ratio (WLR) measured by adaptive optics camera was significantly higher in the PDR groups than in all of the other groups (all P < 0.001). However, the external diameter of the retinal vessels was not significantly different among the groups. The mean blur rate (MBR)-vessel determined by laser speckle flowgraphy was significantly lower in the PDR group than in the other groups (P < 0.001). The WLR was correlated with MBR-vessel (r = − 0.337, P < 0.001), duration of disease (r = 0.191, P = 0.042), stage of DM (r = 0.643, P < 0.001), systolic blood pressure (r = 0.166, P < 0.037), and presence of systemic hypertension (r = 0.443, P < 0.001). Multiple regression analysis demonstrated that MBR-vessel (β = − 0.389, P < 0.001), presence of systemic hypertension (β = 0.334, P = 0.001), and LDL (β = 0.199, P = 0.045) were independent factors significantly associated with the WLR. The increased retinal vessel wall thickness led to a narrowing of lumen diameter and a decrease in the blood flow in the PDR group.
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Campagnoli TR, Somfai GM, Tian J, DeBuc DC, Smiddy WE. Exploratory study of non-invasive, high-resolution functional macular imaging in subjects with diabetic retinopathy. Int J Ophthalmol 2021; 14:57-63. [PMID: 33469484 DOI: 10.18240/ijo.2021.01.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 09/03/2020] [Indexed: 11/23/2022] Open
Abstract
AIM To evaluate a high-resolution functional imaging device that yields quantitative data regarding macular blood flow and capillary network features in eyes with diabetic retinopathy (DR). METHODS Prospective, cross-sectional comparative case-series in which blood flow velocities (BFVs) and non-invasive capillary perfusion maps (nCPMs) in macular vessels were measured in patients with DR and in healthy controls using the Retinal Functional Imager (RFI) device. RESULTS A total of 27 eyes of 21 subjects were studied [9 eyes nonproliferative diabetic retinopathy (NPDR), 9 eyes proliferative diabetic retinopathy (PDR) and 9 controls]. All diabetic patients were type 2. All patients with NPDR and 5 eyes with PDR also had diabetic macular edema (DME). The NPDR group included eyes with severe (n=3) and moderate NPDR (n=6), and were symptomatic. A significant decrease in venular BFVs was observed in the macular region of PDR eyes when compared to controls (2.61±0.6 mm/s and 2.92±0.72 mm/s in PDR and controls, respectively, P=0.019) as well as PDR eyes with DME compared to NPDR eyes (2.36±0.51 mm/s and 2.94±1.09 mm/s in PDR with DME and NPDR, respectively, P=0.01). CONCLUSION The RFI, a non-invasive imaging tool, provides high-resolution functional imaging of the retinal microvasculature and quantitative measurement of BFVs in visually impaired DR patients. The isolated diminish venular BFVs in PDR eyes compared to healthy eyes and PDR eyes with DME in comparison to NPDR eyes may indicate the possibility of more retinal vein compromise than suspected in advanced DR.
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Affiliation(s)
- Thalmon R Campagnoli
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Gábor Márk Somfai
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.,Department of Ophthalmology, Semmelweis University, Faculty of Medicine, Budapest, Hungary
| | - Jing Tian
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Delia Cabrera DeBuc
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - William E Smiddy
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Retinal Microcirculation and Cytokines as Predictors for Recurrence of Macular Edema after Intravitreal Ranibizumab Injection in Branch Retinal Vein Occlusion. J Clin Med 2020; 10:jcm10010058. [PMID: 33375281 PMCID: PMC7796037 DOI: 10.3390/jcm10010058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
Purpose: To investigate the relationship between retinal blood flow, presence or absence of recurrence of macular edema, and levels of cytokines, after intravitreal ranibizumab injection (IRI) in patients with branch retinal vein occlusion (BRVO). Methods: In 47 patients with BRVO and macular edema, we used laser speckle flowgraphy (LSFG) to measure the relative flow volume (RFV) of the retinal arteries and veins passing through the optic disc in the occluded and non-occluded regions of the retina before and after IRI. Aqueous humor samples were obtained at the time of IRI. Levels of vascular endothelial growth factor (VEGF), soluble VEGF receptor (sVEGFR)-1, sVEGFR-2, placental growth factor (PlGF), platelet-derived growth factor (PDGF)-AA, soluble intercellular adhesion molecule (sICAM)-1, monocyte chemoattractant protein 1 (MCP-1), interleukin (IL)-6, IL-8, IL-12 (p70), IL-13 and interferon-inducible 10-kDa protein (IP-10) were measured by the suspension array method. Patients were categorized into two groups on the basis of whether or not macular edema recurred at 2 months after IRI: the nonrecurrent group, n = 24; and the recurrent group, n = 23. Results: In the veins of the occluded region, RFV showed a significant difference between baseline and 1 month after IRI (p < 0.001) in the recurrent group and the percent change of RFV showed a significant difference between the recurrent and nonrecurrent groups (p = 0.005). Furthermore, we found a significant negative correlation between RFV in the veins of the occluded region and aqueous levels of MCP-1, IL-8 and IP-10 at baseline (p = 0.029, p = 0.035, and p = 0.039, respectively). In the recurrent group, the arteries and veins of the non-occluded and occluded regions showed no significant association between RFV and the aqueous levels of any factors. Conclusions: These findings suggested that a decrease in RFV in the veins of the occluded region might be associated with the recurrence of macular edema and that the recurrence might depend on the change in RFV in the veins of the occluded region rather than the levels of cytokines.
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Kanagaraju V, Divya K, Raajaganesh M, Devanand B. Evaluation of Resistive Index of Orbital Vessels Using Color Doppler Imaging in Patients with Type 2 Diabetes Mellitus. J Med Ultrasound 2020; 29:111-115. [PMID: 34377642 PMCID: PMC8330686 DOI: 10.4103/jmu.jmu_88_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/21/2020] [Accepted: 08/24/2020] [Indexed: 11/04/2022] Open
Abstract
Background Resistive index (RI), derived from color Doppler imaging (CDI), is a marker of vascular resistance used widely in varied clinical settings. The aim of this study was to analyze the association between RIs of the orbital vessels in a pure cohort of type 2 diabetic patients with or without retinopathy using CDI. Methods Fifty patients having type 2 diabetes and 50 age-matched controls were evaluated in this prospective study. Diabetic retinopathy (DR) was diagnosed based on seven-field stereo fundus photography and diabetic patients were divided into two. Patients with no DR (n = 26) were taken as Group 1, while patients with DR (n = 24) were taken as Group 2. CDI was performed and the RIs of the ophthalmic artery (OA), posterior ciliary artery (PCA), central retinal artery (CRA), and central retinal vein (CRV) were measured. Results Significant differences were observed in the mean RI values of all orbital arteries between controls and patients with DR (P < 0.05). Comparison of RI values between controls and Group 1 showed no significant differences. Mean RI values of the PCA and CRA were found to be significantly higher in the patients in Group 2 than in Group 1 (P = 0.03 and P < 0.001, respectively). The duration of diabetes correlated with the mean RI of all the orbital vessels. RI of the CRA was a reliable predictive indicator for DR (P = 0.001). Conclusion RIs of the orbital arteries are significantly higher in patients with DR. RI of the orbital vessels can be a potentially useful biomarker in the early diagnosis and follow-up of patients with DR.
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Affiliation(s)
- Vikrant Kanagaraju
- Department of Radiology, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India
| | - K Divya
- Department of Ophthalmology, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India
| | - M Raajaganesh
- Department of Ophthalmology, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India
| | - B Devanand
- Department of Radiology, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India
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Hein TW, Omae T, Xu W, Yoshida A, Kuo L. Role of Arginase in Selective Impairment of Endothelium-Dependent Nitric Oxide Synthase-Mediated Dilation of Retinal Arterioles during Early Diabetes. Invest Ophthalmol Vis Sci 2020; 61:36. [PMID: 32437549 PMCID: PMC7405695 DOI: 10.1167/iovs.61.5.36] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose Retinal vasomotor activity can be regulated by two major endothelial enzymes, nitric oxide synthase (NOS) and cyclooxygenase (COX). The vascular arginase also consumes a NOS substrate and thus impedes NOS-mediated vasodilation. Diabetes mellitus exhibits vascular complications in the retina with elevated oxidative stress and compromised NOS-mediated vasodilation. However, the underlying molecular mechanisms remain unclear, and the effect of diabetes on COX-mediated vasodilation is unknown. Herein, we examined the relative impact of diabetes on retinal arteriolar dilations to COX and NOS activation and the roles of arginase and superoxide in diabetes-induced vasomotor dysfunction. Methods Retinal arterioles were isolated from streptozocin-induced diabetic pigs (2 weeks of hyperglycemia, 433 ± 27 mg/dL) or age-matched control pigs (97 ± 4 mg/dL). The vasodilations to bradykinin (NOS activator) and histamine (NOS/COX activator) were examined in vitro. Results Retinal arteriolar dilations to histamine and bradykinin were significantly reduced after 2 weeks of diabetes. The NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) attenuated the dilations of control vessels, but not diabetic vessels, to histamine. In the presence of L-NAME and COX inhibitor indomethacin, histamine-induced dilations of control and diabetic vessels were reduced similarly. Treatment of diabetic vessels with arginase inhibitor nor-NOHA, but not superoxide dismutase mimetic TEMPOL, preserved both histamine- and bradykinin-induced dilations in an L-NAME-sensitive manner. Conclusions Arginase, rather than superoxide, impairs endothelium-dependent NOS-mediated dilation of retinal arterioles during diabetes, whereas vasodilation mediated by COX remains intact. Blockade of vascular arginase may improve endothelial function of retinal arterioles during early onset of diabetes.
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Wright WS, Eshaq RS, Lee M, Kaur G, Harris NR. Retinal Physiology and Circulation: Effect of Diabetes. Compr Physiol 2020; 10:933-974. [PMID: 32941691 PMCID: PMC10088460 DOI: 10.1002/cphy.c190021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this article, we present a discussion of diabetes and its complications, including the macrovascular and microvascular effects, with the latter of consequence to the retina. We will discuss the anatomy and physiology of the retina, including aspects of metabolism and mechanisms of oxygenation, with the latter accomplished via a combination of the retinal and choroidal blood circulations. Both of these vasculatures are altered in diabetes, with the retinal circulation intimately involved in the pathology of diabetic retinopathy. The later stages of diabetic retinopathy involve poorly controlled angiogenesis that is of great concern, but in our discussion, we will focus more on several alterations in the retinal circulation occurring earlier in the progression of disease, including reductions in blood flow and a possible redistribution of perfusion that may leave some areas of the retina ischemic and hypoxic. Finally, we include in this article a more recent area of investigation regarding the diabetic retinal vasculature, that is, the alterations to the endothelial surface layer that normally plays a vital role in maintaining physiological functions. © 2020 American Physiological Society. Compr Physiol 10:933-974, 2020.
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Affiliation(s)
- William S Wright
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, South Carolina, USA
| | - Randa S Eshaq
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Minsup Lee
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Gaganpreet Kaur
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Norman R Harris
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
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13
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Qiu X, Wang X, Hong P, Liu M, Wen Q, Chen Q. Retinal blood oxygen saturation and vascular endothelial growth factor-A in early diabetic retinopathy: A protocol for systematic review and meta-analysis. Medicine (Baltimore) 2020; 99:e20562. [PMID: 32541481 PMCID: PMC7302675 DOI: 10.1097/md.0000000000020562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Diabetic retinopathy (DR) remains the most common microvascular complication of diabetes; both its high prevalence and associated high risk of vision loss lead it to the major global health burden. Despite significant research efforts, there still remains much of the underlying pathology not fully understand. In the past studies, inner retinal blood flow disturbances are widely assessed as a potential biomarker of DR. However, the results have been variable and even contradictory. Improved methods to figure out the metabolic disturbances associated with DR are essential. Some research showed that both vascular endothelial growth factor-A and blood oxygen saturation are higher in DR patients and correlated with disease severity. Therefore, we decided to conduct a systematic review and meta-analysis to find out the connection of them and provide robust evidence on the mechanism underlying this connection to help us better understand the pathophysiology behind the hypoxic retina and find better ways to treat DR. METHODS This study will be conducted according to Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. We will do electronic searches from PubMed, EMBASE, Web of Science, Cochrane Library, Wanfang database, CNKI, and VIP database. Two reviewers will screen all the references independently and any disagreement will be solved by the third involvement. All data will be extracted by 2 independent reviewers according to a standardized data extraction sheet. Based on the type of studies, 2 reviewers will independently use different scales to assess the risk of bias. Any disagreements and conflicts will be resolved by discussing it with a third reviewer. We will conduct a random-effects meta-analysis. Individual and pooled odds ratios/relative risks and associated 95% confidence intervals will be calculated as well as between-study heterogeneity. The potential for publication bias will also be evaluated. If possible, we will explore reasons for potential between-study heterogeneity. RESULTS This study is a protocol for systematic review and meta-analysis without results. Associated data analysis will be carried out after the protocol. CONCLUSION The protocol aims to guide a meta-analysis whose purpose is investigating the association between retinal blood oxygen saturation and vascular endothelial growth factors in patients with early DR and trying to find out the mechanism that the changing of retinal oxygen saturation in patients with DR. INPLASY REGISTRATION NUMBER INPLASY202040161.
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Affiliation(s)
- Xianliang Qiu
- School of Clinical Medicine, Hospital of Chengdu University of Traditional Chinese Medicine
| | - Xian Wang
- School of Clinical Medicine, Hospital of Chengdu University of Traditional Chinese Medicine
| | - Peipei Hong
- School of Clinical Medicine, Hospital of Chengdu University of Traditional Chinese Medicine
| | - Min Liu
- School of Clinical Medicine, Hospital of Chengdu University of Traditional Chinese Medicine
| | - Qing Wen
- School of Clinical Medicine, Hospital of Chengdu University of Traditional Chinese Medicine
| | - Qiu Chen
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
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14
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Blindbæk SL, Peto T, Grauslund J. Retinal arteriolar oxygen saturation predicts the need for intravitreal aflibercept in patients with diabetic macular oedema. BMJ Open Ophthalmol 2020; 5:e000382. [PMID: 32524033 PMCID: PMC7259848 DOI: 10.1136/bmjophth-2019-000382] [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: 08/07/2019] [Revised: 10/07/2019] [Accepted: 12/09/2019] [Indexed: 11/25/2022] Open
Abstract
Objective Given the increasing burden of repetitive intravitreal injections in diabetic macular oedema (DMO) treatment, non-invasive markers of treatment outcome are needed. Hence, we aimed to examine retinal oximetry parameters as markers of need for intravitreal aflibercept in patients with DMO. Methods This study was based on data from a 12-month clinical trial including 35 eyes of 25 patients with centre involving DMO. Retinal oximetry, visual acuity (VA) and central retinal thickness (CRT) were performed at baseline (BL). Patients then received 3 monthly injections of aflibercept followed by focal/grid laser photocoagulation. From month 4 (M4) through 12 (M12), patients were followed monthly and additional injections were given pro re nata if criteria of retreatment were met. We evaluated the difference in need for intravitreal aflibercept in groups of eyes with the highest and lowest retinal arteriolar and venular oxygen saturations, respectively. Results From BL-M12, overall VA letter score improved by 8.7 (7.2–10.2). Likewise CRT reduced by 100.7 (68.2–133.3) µm and the mean number of injections was 4.3 (3.8–4.8). Overall retinal arteriolar and venular oxygen saturations were 95.7 (93.0–98.4)% and 62.7 (59.4–65.9)% at BL. Eyes with the highest retinal arteriolar oxygen saturations had significantly more injections between BL and M12 compared with eyes with the lowest retinal arteriolar oxygen saturations (5.0 (4.2–5.8) vs 3.6 (3.1–4.0), p=0.002). Conclusion Higher retinal arteriolar oxygen saturation independently predicted the need for more intravitreal aflibercept during the first year of DMO treatment and may serve as a valuable adjunctive to established procedures for retinal imaging in terms of individualised treatment plans. Trial registration number NCT02554747
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Affiliation(s)
- Søren Leer Blindbæk
- Department of Ophthalmology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,OPEN, Open Patient data Explorative Network, Odense University Hospital, Odense, Denmark
| | - Tunde Peto
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom
| | - Jakob Grauslund
- Department of Ophthalmology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Steno Diabetes Center Odense, Odense, Denmark
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15
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Harris NR, Leskova W, Kaur G, Eshaq RS, Carter PR. Blood flow distribution and the endothelial surface layer in the diabetic retina. Biorheology 2020; 56:181-189. [PMID: 30958328 PMCID: PMC10082436 DOI: 10.3233/bir-180200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetic retinopathy is known as a microvascular complication of hyperglycemia, with a breakdown of the blood-retinal barrier, loss of pericytes, formation of microhemorrhages, early decreases in perfusion and areas of ischemia, with the latter speculated to induce the eventual proliferative, angiogenic phase of the disease. Our animal models of diabetic retinopathy demonstrate similar decreases in retinal blood flow as seen in the early stages of diabetes in humans. Our studies also show an alteration in the retinal distribution of red blood cells, with the deep capillary layer receiving a reduced fraction, and with flow being diverted more towards the superficial vascular layer. Normal red blood cell distribution is dependent on the presence of the endothelial surface layer, specifically the glycocalyx, which has been reported to be partially lost in the diabetic retina of both humans and animals. This review addresses these two phenomena in diabetes: altered perfusion patterns and loss of the glycocalyx, with a possible connection between the two.
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Affiliation(s)
- Norman R Harris
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Wendy Leskova
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Gaganpreet Kaur
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Randa S Eshaq
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Patsy R Carter
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
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16
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Rostamkhani H, Mellati AA, Tabaei BS, Alavi M, Mousavi SN. Association of Serum Zinc and Vitamin A Levels with Severity of Retinopathy in Type 2 Diabetic Patients: a Cross-Sectional Study. Biol Trace Elem Res 2019; 192:123-128. [PMID: 30790120 DOI: 10.1007/s12011-019-01664-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/04/2019] [Indexed: 10/27/2022]
Abstract
Diabetic retinopathy (DR) is a common microvascular disorder which occurs in type 2 diabetes mellitus (T2DM) patients due to chronic hyperglycemia. Previous studies reported that serum zinc (Zn) and vitamin A levels were associated with certain diabetic microvascular complications. However, the relationship between Zn and vitamin A levels with the severity of DR in type 2 diabetic patients is not clear. We aimed to analyze the relationship between serum Zn and vitamin A levels with the severity of DR in T2DM. Sixty T2DM patients were selected from whom attending to the ophthalmology center of hospital from June 2017 and Feb 2018. Patients were categorized as controls, non-proliferative DR (NPDR), and proliferative DR (PDR). Anthropometric, dietary, and physical activity data were gathered. Fasting blood samples were taken to measure biochemical parameters. Serum Zn and vitamin A levels were measured via enzymatic-calorimetric and HPLC methods, respectively. Results showed that serum Zn and vitamin A levels were significantly lower in the PDR group than the controls (p = 0.03 and p = 0.008, respectively). Serum low-density lipoprotein (LDL.C) was significantly higher in the PDR than the control group (p = 0.02). Adjusting for the other variables, increase in serum Zn and vitamin A levels reduced risk of DR by 25.7% and 31.1%, respectively (p = 0.02 and p = 0.007). Higher serum LDL.C increased DR severity by 28.7%, adjusted for the variables (95% CI = 0.002, 0.02; p = 0.01). Lower serum Zn and vitamin A levels, as well as higher LDL.C in the T2DM patients, are related to DR severity.
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Affiliation(s)
- Hadi Rostamkhani
- Department of Clinical Biochemistry, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
- Student Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Ali Awsat Mellati
- Department of Clinical Biochemistry, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Banafsheh Sadat Tabaei
- Department of Clinical Biochemistry, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Mohammadhossein Alavi
- Department of Biothechnology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Seyedeh Neda Mousavi
- Department of Nutrition, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
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17
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Climie RE, Gallo A, Picone DS, Di Lascio N, van Sloten TT, Guala A, Mayer CC, Hametner B, Bruno RM. Measuring the Interaction Between the Macro- and Micro-Vasculature. Front Cardiovasc Med 2019; 6:169. [PMID: 31824963 PMCID: PMC6882776 DOI: 10.3389/fcvm.2019.00169] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/07/2019] [Indexed: 01/09/2023] Open
Abstract
Structural and functional dysfunction in both the macro- and microvasculature are a feature of essential hypertension. In a healthy cardiovascular system, the elastic properties of the large arteries ensure that pulsations in pressure and flow generated by cyclic left ventricular contraction are dampened, so that less pulsatile pressure and flow are delivered at the microvascular level. However, in response to aging, hypertension, and other disease states, arterial stiffening limits the buffering capacity of the elastic arteries, thus exposing the microvasculature to increased pulsatile stress. This is thought to be particularly pertinent to high flow/low resistance organs such as the brain and kidney, which may be sensitive to excess pressure and flow pulsatility, damaging capillary networks, and resulting in target organ damage. In this review, we describe the clinical relevance of the pulsatile interaction between the macro- and microvasculature and summarize current methods for measuring the transmission of pulsatility between the two sites.
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Affiliation(s)
- Rachel E Climie
- INSERM, U970, Paris Cardiovascular Research Center (PARCC), Paris Descartes University, Paris, France.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Menzies Institute for Medical Research, University of Tasmanian, Hobart, TAS, Australia
| | - Antonio Gallo
- Cardiovascular Prevention Unit, Department of Endocrinology and Metabolism, Pitié-Salpêtrière Hospital, Paris, France.,Laboratoire d'imagerie Biomédicale, INSERM 1146 - CNRS 7371, Sorbonne University, Paris, France
| | - Dean S Picone
- Menzies Institute for Medical Research, University of Tasmanian, Hobart, TAS, Australia
| | - Nicole Di Lascio
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Thomas T van Sloten
- INSERM, U970, Paris Cardiovascular Research Center (PARCC), Paris Descartes University, Paris, France.,Cardiovascular Research Institute Maastricht and Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Andrea Guala
- Department of Cardiology, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institute of Research, Barcelona, Spain
| | - Christopher C Mayer
- AIT Austrian Institute of Technology GmbH, Center for Health & Bioresources, Biomedical Systems, Vienna, Austria
| | - Bernhard Hametner
- AIT Austrian Institute of Technology GmbH, Center for Health & Bioresources, Biomedical Systems, Vienna, Austria
| | - Rosa Maria Bruno
- INSERM, U970, Paris Cardiovascular Research Center (PARCC), Paris Descartes University, Paris, France
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18
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Blindbæk SL, Peto T, Grauslund J. Correlation between Diabetic Retinopathy Severity and Oxygen Metabolism in Patients with Diabetic Macular Edema during Treatment with Intravitreal Aflibercept. Ophthalmic Res 2019; 63:106-113. [PMID: 31715608 DOI: 10.1159/000503930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/06/2019] [Indexed: 12/31/2022]
Abstract
PURPOSE To attribute data on changes in diabetic retinopathy (DR) severity during treatment of diabetic macular edema (DME) with vascular endothelial growth factor inhibitors (anti-VEGF), this study aimed to (1) examine the correlation between oxygen saturations in retinal vessels and the number of DR lesions on ultra-wide field color fundus photographs prior to anti-VEGF treatment and (2) compare changes in oxygen saturations in retinal vessels with changes in the number of DR lesions after a loading dose of three monthly intravitreal injections of 2.0 mg of aflibercept. METHODS This 3-month prospective study included 37 eyes of patients with DME and varying severity of peripheral DR lesions. DR lesions were graded on wide field images and retinal oxygen saturations were evaluated by retinal oximetry. Patients were then treated with three monthly intravitreal injections of 2 mg aflibercept and wide field imaging and retinal oximetry were repeated 4 weeks after the last injection. Patients with proliferative DR or previous panretinal photocoagulation were excluded. RESULTS Baseline retinal arteriolar oxygen saturation increased with increasing DR severity and numbers of microaneurysms, hemorrhages, and cotton wool spots (p = 0.03, 0.01, 0.03, and <0.001), while no correlation between the severity of DR lesions and retinal venular oxygen saturation was found. After treatment with intravitreal aflibercept, the severity of DR lesions significantly reduced, while retinal arteriolar and venular oxygen saturation as well as the arteriolar-venular difference remained unchanged (95.5 vs. 95.8%, p = 0.44; 62.9 vs. 64.5%, p = 0.08; 32.5 vs. 31.4%, p = 0.33). CONCLUSION This study demonstrated that structural DR lesions correlate with retinal arteriolar oxygen saturation in patients with DME prior to anti-VEGF treatment and that improvement in the severity of DR lesions can occur without corresponding changes in retinal oxygen metabolism during intravitreal therapy. Our results suggest that DR severity on color fundus photographs should be interpreted with caution once intravitreal therapy is initiated.
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Affiliation(s)
- Søren Leer Blindbæk
- Department of Ophthalmology, Odense University Hospital, Odense, Denmark, .,Department of Clinical Research, University of Southern Denmark, Odense, Denmark, .,OPEN, Odense Patient data Explorative Network, Odense University Hospital, Odense, Denmark,
| | - Tunde Peto
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom
| | - Jakob Grauslund
- Department of Ophthalmology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
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19
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Retinal Blood Velocity and Flow in Early Diabetes and Diabetic Retinopathy Using Adaptive Optics Scanning Laser Ophthalmoscopy. J Clin Med 2019; 8:jcm8081165. [PMID: 31382617 PMCID: PMC6723736 DOI: 10.3390/jcm8081165] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/18/2019] [Accepted: 07/29/2019] [Indexed: 01/13/2023] Open
Abstract
Using adaptive optics scanning laser ophthalmoscopy (AOSLO), we measured retinal blood velocity and flow in healthy control eyes and eyes of diabetic patients with or without retinopathy. This cross-sectional study included 39 eyes of 30 patients with diabetes (DM) with mild non-proliferative diabetic retinopathy (NPDR) or without retinopathy (DM no DR) and 21 eyes of 17 healthy age-matched controls. Participants were imaged with a commercial optical coherence tomography angiography (OCTA) device (RTVue-XR Avanti) and AOSLO device (Apaeros Retinal Imaging System, Boston Micromachines). We analyzed AOSLO-based retinal blood velocity and flow, and OCTA-based vessel density of the superficial (SCP), deep retinal capillary plexus (DCP), and full retina. Retinal blood velocity was significantly higher in eyes with DM no DR and lower in NPDR across all vessel diameters compared to controls. Retinal blood flow was significantly higher in DM no DR and lower in NPDR in vessel diameters up to 60 μm compared to controls. When comparing flow outliers (low-flow DM no DR eyes and high-flow NPDR eyes), we found they had a significantly different retinal vessel density compared to the remaining eyes in the respective groups. Retinal blood velocity and flow is increased in eyes with DM no DR, while these parameters are decreased in eyes with mild NPDR compared to healthy age-matched controls. The similarity of OCTA vessel density among outliers in the two diabetic groups suggests an initial increase followed by progressive decline in blood flow and OCTA vessel density with progression to clinical retinopathy, which warrants further investigation.
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20
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Tayyari F, Khuu L, Sivak JM, Flanagan JG, Singer S, Brent MH, Hudson C. Retinal blood oxygen saturation and aqueous humour biomarkers in early diabetic retinopathy. Acta Ophthalmol 2019; 97:e673-e679. [PMID: 30690929 DOI: 10.1111/aos.14016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 12/06/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE The aim of this study was to assess the relationship between retinal blood oxygen saturation (SO2 ) and specific aqueous humour (AH) concentrations of proangiogenic biomarkers in diabetic patients with nonproliferative diabetic retinopathy (NPDR) and to compare them with those of matched control subjects. METHODS The sample comprised 14 participants with mild-to-moderate NPDR (69.1 ± 6.6 years) and 17 age-matched healthy controls (69.7 ± 6.3 years); all participants were previously scheduled for routine cataract extraction with intraocular lens implantation. Multiplex cytokine analyses of specific biomarkers, including vascular endothelial growth factor A (VEGF-A), angiopoietin2 (Ang2), epidermal growth factor (EGF), hepatocyte growth factor (HGF) and interleukin-8 (IL-8) were performed by BioPlex 200 system. Six non-invasive hyperspectral retinal images were acquired. RESULTS Mean SO2 was significantly higher in both arterioles (94.4 ± 1.9 versus 93.0 ± 1.6) and venules (64.4 ± 5.6 versus 55.9 ± 4.8) of NPDR than in the healthy controls (p < 0.001). AH levels of HGF (p = 0.018), Ang2 (p = 0.005) and IL-8 (p = 0.034) were significantly higher, and EGF (p = 0.030) was significantly lower in NPDR subjects. The study demonstrated a correlation between venular retinal blood oxygen saturation and proangiogenic factors HGF (r = 0.558, p = 0.038), Ang2 (r = 0.556, p = 0.039) and EGF (r = -0.554, p = 0.040), but did not find any correlation for IL-8 (r = 0.330, p = 0.249) even though this biomarker was significantly higher in the diabetic group. CONCLUSION To our knowledge, the present study is the first report considering the association between SO2 and AH concentrations of protein biomarkers in diabetic retinopathy. The biomarkers of interest have been shown to participate in cell death, which may explain higher oxygen saturation in NPDR.
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Affiliation(s)
- Faryan Tayyari
- Retina Research Group School of Optometry and Vision Science University of Waterloo Waterloo Ontario Canada
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
| | - Lee‐Anne Khuu
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
| | - Jeremy M. Sivak
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
| | - John G. Flanagan
- Retina Research Group School of Optometry and Vision Science University of Waterloo Waterloo Ontario Canada
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
| | - Shaun Singer
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
| | - Michael H. Brent
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
| | - Christopher Hudson
- Retina Research Group School of Optometry and Vision Science University of Waterloo Waterloo Ontario Canada
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
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21
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Orduña Ríos M, Noguez Imm R, Hernández Godínez NM, Bautista Cortes AM, López Escalante DD, Liedtke W, Martínez Torres A, Concha L, Thébault S. TRPV4 inhibition prevents increased water diffusion and blood-retina barrier breakdown in the retina of streptozotocin-induced diabetic mice. PLoS One 2019; 14:e0212158. [PMID: 31048895 PMCID: PMC6497373 DOI: 10.1371/journal.pone.0212158] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/09/2019] [Indexed: 01/02/2023] Open
Abstract
A better understanding of the molecular and cellular mechanisms involved in retinal hydro-mineral homeostasis imbalance during diabetic macular edema (DME) is needed to gain insights into retinal (patho-)physiology that will help elaborate innovative therapies with lower health care costs. Transient receptor potential cation channel subfamily vanilloid member 4 (TRPV4) plays an intricate role in homeostatic processes that needs to be deciphered in normal and diabetic retina. Based on previous findings showing that TRPV4 antagonists resolve blood-retina barrier (BRB) breakdown in diabetic rats, we evaluated whether TRPV4 channel inhibition prevents and reverts retinal edema in streptozotocin(STZ)-induced diabetic mice. We assessed retinal edema using common metrics, including retinal morphology/thickness (histology) and BRB integrity (albumin-associated tracer), and also by quantifying water mobility through apparent diffusion coefficient (ADC) measures. ADC was measured by diffusion-weighted magnetic resonance imaging (DW-MRI), acquired ex vivo at 4 weeks after STZ injection in diabetes and control groups. DWI images were also used to assess retinal thickness. TRPV4 was genetically ablated or pharmacologically inhibited as follows: left eyes were used as vehicle control and right eyes were intravitreally injected with TRPV4-selective antagonist GSK2193874, 24 h before the end of the 4 weeks of diabetes. Histological data show that retinal thickness was similar in nondiabetic and diabetic wt groups but increased in diabetic Trpv4-/- mice. In contrast, DWI shows retinal thinning in diabetic wt mice that was absent in diabetic Trpv4-/- mice. Disorganized outer nuclear layer was observed in diabetic wt but not in diabetic Trpv4-/- retinas. We further demonstrate increased water diffusion, increased distances between photoreceptor nuclei, reduced nuclear area in all nuclear layers, and BRB hyperpermeability, in diabetic wt mice, effects that were absent in diabetic Trpv4-/- mice. Retinas of diabetic mice treated with PBS showed increased water diffusion that was not normalized by GSK2193874. ADC maps in nondiabetic Trpv4-/- mouse retinas showed restricted diffusion. Our data provide evidence that water diffusion is increased in diabetic mouse retinas and that TRPV4 function contributes to retinal hydro-mineral homeostasis and structure under control conditions, and to the development of BRB breakdown and increased water diffusion in the retina under diabetes conditions. A single intravitreous injection of TRPV4 antagonist is however not sufficient to revert these alterations in diabetic mouse retinas.
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Affiliation(s)
- Maricruz Orduña Ríos
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Ramsés Noguez Imm
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | | | - Ana María Bautista Cortes
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | | | - Wolfgang Liedtke
- Department of Medicine and Neurobiology, Center for Translational Neuroscience, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Atáulfo Martínez Torres
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Luis Concha
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
| | - Stéphanie Thébault
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Campus UNAM-Juriquilla, Querétaro, México
- * E-mail:
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22
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Agrawal R, Balne PK, Tun SBB, Sia Wey Y, Khandelwal N, Barathi VA. Fluorescent Dye Labeling of Erythrocytes and Leukocytes for Studying the Flow Dynamics in Mouse Retinal Circulation. J Vis Exp 2017. [PMID: 28715402 DOI: 10.3791/55495] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The retinal and choroidal blood flow dynamics may provide insight into the pathophysiology and sequelae of various ocular diseases, such as glaucoma, diabetic retinopathy, age-related macular degeneration (AMD) and other ocular inflammatory conditions. It may also help to monitor the therapeutic responses in the eye. The proper labeling of the blood cells, coupled with live-cell imaging of the labeled cells, allows for the investigation of the flow dynamics in the retinal and choroidal circulation. Here, we describe the standardized protocols of 1.5% indocyanine green (ICG) and 1% sodium fluorescein labeling of mice erythrocytes and leukocytes, respectively. Scanning laser ophthalmoscopy (SLO) was applied to visualize the labeled cells in the retinal circulation of C57BL/6J mice (wild type). Both methods demonstrated distinct fluorescently labeled cells in the mouse retinal circulation. These labeling methods can have wider applications in various ocular disease models.
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Affiliation(s)
- Rupesh Agrawal
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital; Singapore Eye Research Institute (SERI), Singapore National Eye Center; School of Material Science and Engineering, Nanyang Technological University;
| | | | - Sai Bo Bo Tun
- Singapore Eye Research Institute (SERI), Singapore National Eye Center
| | - Yeo Sia Wey
- Singapore Eye Research Institute (SERI), Singapore National Eye Center
| | - Neha Khandelwal
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital
| | - Veluchamy A Barathi
- Singapore Eye Research Institute (SERI), Singapore National Eye Center; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University Health Systems, National University of Singapore; Ophthalmology Academic Clinical Research Program, DUKE-NUS Graduate Medical School;
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Pechauer AD, Hwang TS, Hagag AM, Liu L, Tan O, Zhang X, Parker M, Huang D, Wilson DJ, Jia Y. Assessing total retinal blood flow in diabetic retinopathy using multiplane en face Doppler optical coherence tomography. Br J Ophthalmol 2017; 102:126-130. [PMID: 28495904 DOI: 10.1136/bjophthalmol-2016-310042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/19/2017] [Accepted: 04/23/2017] [Indexed: 01/05/2023]
Abstract
AIM To assess total retinal blood flow (TRBF) in diabetic retinopathy (DR) using multiplane en face Doppler optical coherence tomography (OCT). METHODS A 70 kHz spectral-domain OCT system scanned a 2×2 mm area centred at the optic disc of the eyes with DR and healthy participants. The multiplane en face Doppler OCT algorithm generated a three-dimensional volumetric data set consisting of 195 en face planes. The TRBF was calculated from the maximum flow values of each branching retinal vein at an optimised en face plane. DR severity was graded according to the international clinical classification system. The generalised linear model method was used to compare flow values between DR groups and the control group. RESULTS A total of 71 eyes from 71 participants were included. Ten eyes were excluded due to poor image quality. The within-visit repeatability of scans was 4.1% (coefficient of variation). There was no significant difference in the TRBF between the healthy (46.7±10.2 µL/min) and mild/moderate non-proliferative DR (44.9±12.6 µL/min) groups. The TRBF in severe non-proliferative DR (39.1±12.6 µL/min) and proliferative DR (28.9±8.85 µL/min) groups were significantly lower (p=0.04 and p<0.0001, respectively) than that of the healthy group. TRBF was correlated with DR disease severity (p<0.0001, linear trend test). CONCLUSION The novel multiplane en face Doppler OCT method provided reliable measurements of TRBF in DR eyes. This may be a useful tool in understanding the pathophysiology of DR.
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Affiliation(s)
- Alex D Pechauer
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Thomas S Hwang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Ahmed M Hagag
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Liang Liu
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Ou Tan
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Xinbo Zhang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Maria Parker
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - David J Wilson
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
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Khuu LA, Tayyari F, Sivak JM, Flanagan JG, Singer S, Brent MH, Huang D, Tan O, Hudson C. Aqueous humour concentrations of TGF-β, PLGF and FGF-1 and total retinal blood flow in patients with early non-proliferative diabetic retinopathy. Acta Ophthalmol 2017; 95:e206-e211. [PMID: 27678201 DOI: 10.1111/aos.13230] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 07/11/2016] [Indexed: 12/21/2022]
Abstract
PURPOSE To correlate angiogenic cytokines in the aqueous humour with total retinal blood flow in subjects with type 2 diabetes with non-proliferative diabetic retinopathy (NPDR). METHODS A total of 17 controls and 16 NPDR patients were recruited into the study. Aqueous humour was collected at the start of cataract surgery to assess the concentration of 14 angiogenic cytokines. Aqueous humour was analysed using the suspension array method. Six images were acquired to assess total retinal blood flow (TRBF) using the prototype RTVue™ Doppler Fourier domain optical coherence tomography (Doppler FD-OCT) (Optovue, Inc., Fremont, CA) using a double circular scan protocol, 1 month postsurgery. At the same visit, forearm blood was collected to determine glycosylated haemoglobin (A1c). RESULTS Transforming growth factor beta (TGF-β1, TGF-β2) and PLGF were increased while FGF-1 was reduced in NPDR compared to controls (Bonferroni corrected, p < 0.003 for all). Total retinal blood flow (TRBF) was significantly reduced in the NPDR group compared to controls (33.1 ± 9.9 versus 43.3 ± 5.3 μl/min, p = 0.002). Aqueous FGF-1 significantly correlated with TRBF in the NPDR group (r = 0.71, p = 0.01; r2 = 0.51). In a multiple regression analysis, A1c was found to be a significant predictor of aqueous TGF-β1 and FGF-1 (p = 0.018 and p = 0.020, respectively). CONCLUSION Aqueous angiogenic cytokines (TGF-β1, TGF-β2 and PLGF) were elevated in conjunction with a reduction in TRBF in patients with NPDR compared to controls. Non-invasive measurement of TRBF may be useful for predicting aqueous FGF-1 levels and severity of vasculopathy in DR.
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Affiliation(s)
- Lee-Anne Khuu
- Institute of Medical Science; University of Toronto; Toronto ON Canada
- Vision Science and Ophthalmology; Toronto Western Hospital; Toronto ON Canada
| | - Faryan Tayyari
- School of Optometry and Vision Science; University of Waterloo; Waterloo ON Canada
| | - Jeremy M. Sivak
- Vision Science and Ophthalmology; Toronto Western Hospital; Toronto ON Canada
| | - John G. Flanagan
- Institute of Medical Science; University of Toronto; Toronto ON Canada
- Vision Science and Ophthalmology; Toronto Western Hospital; Toronto ON Canada
| | - Shaun Singer
- Vision Science and Ophthalmology; Toronto Western Hospital; Toronto ON Canada
| | - Michael H. Brent
- Vision Science and Ophthalmology; Toronto Western Hospital; Toronto ON Canada
| | - David Huang
- Casey Eye Institute; Oregon Health and Science University; Portland OR USA
| | - Ou Tan
- Casey Eye Institute; Oregon Health and Science University; Portland OR USA
| | - Christopher Hudson
- Institute of Medical Science; University of Toronto; Toronto ON Canada
- Vision Science and Ophthalmology; Toronto Western Hospital; Toronto ON Canada
- School of Optometry and Vision Science; University of Waterloo; Waterloo ON Canada
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Application of Arterial Spin Labelling in the Assessment of Ocular Tissues. BIOMED RESEARCH INTERNATIONAL 2016; 2016:6240504. [PMID: 27066501 PMCID: PMC4811053 DOI: 10.1155/2016/6240504] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/07/2016] [Indexed: 11/17/2022]
Abstract
Arterial spin labelling (ASL) is a noninvasive magnetic resonance imaging (MRI) modality, capable of measuring blood perfusion without the use of a contrast agent. While ASL implementation for imaging the brain and monitoring cerebral blood flow has been reviewed in depth, the technique is yet to be widely used for ocular tissue imaging. The human retina is a very thin but highly stratified structure and it is also situated close to the surface of the body which is not ideal for MR imaging. Hence, the application of MR imaging and ASL in particular has been very challenging for ocular tissues and retina. That is despite the fact that almost all of retinal pathologies are accompanied by blood perfusion irregularities. In this review article, we have focused on the technical aspects of the ASL and their implications for its optimum adaptation for retinal blood perfusion monitoring. Retinal blood perfusion has been assessed through qualitative or invasive quantitative methods but the prospect of imaging flow using ASL would increase monitoring and assessment of retinal pathologies. The review provides details of ASL application in human ocular blood flow assessment.
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Blair NP, Wanek J, Teng PY, Shahidi M. The effect of intravitreal vascular endothelial growth factor on inner retinal oxygen delivery and metabolism in rats. Exp Eye Res 2015; 143:141-7. [PMID: 26518179 DOI: 10.1016/j.exer.2015.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/15/2015] [Accepted: 09/29/2015] [Indexed: 02/08/2023]
Abstract
Vascular endothelial growth factor (VEGF) is stimulated by hypoxia and plays an important role in pathologic vascular leakage and neovascularization. Increased VEGF may affect inner retinal oxygen delivery (DO2) and oxygen metabolism (MO2), however, quantitative information is lacking. We tested the hypotheses that VEGF increases DO2, but does not alter MO2. In 10 rats, VEGF was injected intravitreally into one eye, whereas balanced salt solution (BSS) was injected into the fellow eye, 24 h prior to imaging. Vessel diameters and blood velocities were determined by red-free and fluorescent microsphere imaging, respectively. Vascular PO2 values were derived by phosphorescence lifetime imaging of an intravascular oxyphor. Retinal blood flow, vascular oxygen content, DO2 and MO2 were calculated. Retinal arterial and venous diameters were larger in VEGF-injected eyes compared to control eyes (P < 0.03), however no significant difference was observed in blood velocity (P = 0.21). Thus, retinal blood flow was greater in VEGF-injected eyes (P = 0.007). Retinal vascular PO2 and oxygen content were similar between control and VEGF-injected eyes (P > 0.11), while the arteriovenous oxygen content difference was marginally lower in VEGF-injected eyes (P = 0.05). DO2 was 950 ± 340 and 1380 ± 650 nL O2/min in control and VEGF-injected eyes, respectively (P = 0.005). MO2 was 440 ± 150 and 490 ± 190 nL O2/min in control and VEGF-injected eyes, respectively (P = 0.31). Intravitreally administered VEGF did not alter MO2 but increased DO2, suggesting VEGF may play an offsetting role in conditions characterized by retinal hypoxia.
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Affiliation(s)
- Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
| | - Justin Wanek
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
| | - Pang-yu Teng
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA; UCLA Radiological Sciences, Suite 650, 924 Westwood Boulevard, Los Angeles, CA 90024, USA.
| | - Mahnaz Shahidi
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
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Hein TW, Rosa RH, Ren Y, Xu W, Kuo L. VEGF Receptor-2-Linked PI3K/Calpain/SIRT1 Activation Mediates Retinal Arteriolar Dilations to VEGF and Shear Stress. Invest Ophthalmol Vis Sci 2015; 56:5381-9. [PMID: 26284543 DOI: 10.1167/iovs15-16950] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Vasomotor responses of retinal arterioles to luminal flow/shear stress and VEGF have a critical role in governing retinal blood flow possibly via nitric oxide synthase (NOS) activation. However, the cellular mechanism for flow-sensitive vasomotor activity in relation to VEGF signaling in retinal arterioles has not been characterized. We used an isolated vessel approach to specifically address this issue. METHODS Porcine retinal arterioles were isolated, cannulated, and pressurized to 55 cm H2O luminal pressure by two independent reservoir systems. Luminal flow was increased stepwise by creating hydrostatic pressure gradients across two reservoirs. Diameter changes and associated signaling mechanisms corresponding to increased flow and VEGF receptor 2 (VEGFR2) activation were assessed using videomicroscopic, pharmacological, and molecular tools. RESULTS Retinal arterioles developed basal tone under zero-flow condition and dilated concentration-dependently to VEGF165. Stepwise increases in flow produced graded vasodilation. Vasodilations to VEGF165 and increased flow were abolished by endothelial removal, and inhibited by pharmacological blockade of VEGFR2, NOS, phosphoinositide 3-kinase (PI3K), calpains, or sirtuin-1 (SIRT1) deacetylase. A VEGF165 antibody blocked vasodilation to VEGF165 but not flow. Immunostaining indicated that VEGFR2 was expressed in the endothelial and smooth muscle layers of retinal arterioles. CONCLUSIONS Ligand-dependent and ligand-independent activation of VEGFR2 in the endothelium mediates NO-dependent dilations of porcine retinal arterioles in response to VEGF165 and luminal flow/shear stress, respectively. It appears that NOS stimulation via PI3K, calpain proteases, and SIRT1-dependent deacetylation downstream from VEGFR2 activation contributes to these vasodilator responses.
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Affiliation(s)
- Travis W Hein
- Department of Surgery Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States 2Department of Ophthalmology, Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple
| | - Robert H Rosa
- Department of Surgery Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States 2Department of Ophthalmology, Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple
| | - Yi Ren
- Department of Surgery Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Wenjuan Xu
- Department of Surgery Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Lih Kuo
- Department of Surgery Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States 2Department of Ophthalmology, Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple
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The progress in understanding and treatment of diabetic retinopathy. Prog Retin Eye Res 2015; 51:156-86. [PMID: 26297071 DOI: 10.1016/j.preteyeres.2015.08.001] [Citation(s) in RCA: 611] [Impact Index Per Article: 67.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy is the most frequently occurring complication of diabetes mellitus and remains a leading cause of vision loss globally. Its aetiology and pathology have been extensively studied for half a century, yet there are disappointingly few therapeutic options. Although some new treatments have been introduced for diabetic macular oedema (DMO) (e.g. intravitreal vascular endothelial growth factor inhibitors ('anti-VEGFs') and new steroids), up to 50% of patients fail to respond. Furthermore, for people with proliferative diabetic retinopathy (PDR), laser photocoagulation remains a mainstay therapy, even though it is an inherently destructive procedure. This review summarises the clinical features of diabetic retinopathy and its risk factors. It describes details of retinal pathology and how advances in our understanding of pathogenesis have led to identification of new therapeutic targets. We emphasise that although there have been significant advances, there is still a pressing need for a better understanding basic mechanisms enable development of reliable and robust means to identify patients at highest risk, and to intervene effectively before vision loss occurs.
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Changes in retinal blood flow in patients with macular edema secondary to branch retinal vein occlusion before and after intravitreal injection of bevacizumab. Retina 2015; 34:2037-43. [PMID: 24896136 DOI: 10.1097/iae.0000000000000172] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the effect of intravitreal bevacizumab (IVB) injections for macular edema secondary to acute branch retinal vein occlusion on the retinal microcirculation. METHODS The study was a prospective, interventional case series. Central macular thickness using spectral-domain optical coherence tomography and retinal blood flow (RBF) in untreated eyes with macular edema secondary to acute branch retinal vein occlusion in occluded (V1) and opposite venules in affected eyes (V2) and the equivalent venules in contralateral eyes (V3), using laser Doppler velocimetry during follow-up and after IVB injection, were measured. RESULTS In 33 eyes with acute branch retinal vein occlusion of <2 months of duration at the first visit, changes in the retinal microcirculation for 1 month was observed; the macular edema improved spontaneously, and the RBF was unchanged in 15 of 33 eyes, and the RBF increased by 23.3% in 18 eyes with persistent macular edema. Twenty-four eyes received an IVB injection (1.25 mg per 0.05 mL). The RBF did not change significantly during follow-up. In 8 of 24 eyes (33%) with improved macular edema 3 months after the treatment, the average RBF values before injection were significantly higher compared with that of eyes with recurrent edema. CONCLUSION One IVB injection might have little effect on the retinal microcirculation in patients with macular edema secondary to acute branch retinal vein occlusion at least 3 months after the injection. However, the increased RBF in the occluded venules before injection might be associated with improved macular edema after the IVB injection.
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Semeraro F, Cancarini A, dell'Omo R, Rezzola S, Romano MR, Costagliola C. Diabetic Retinopathy: Vascular and Inflammatory Disease. J Diabetes Res 2015; 2015:582060. [PMID: 26137497 PMCID: PMC4475523 DOI: 10.1155/2015/582060] [Citation(s) in RCA: 263] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 05/03/2015] [Accepted: 05/13/2015] [Indexed: 02/06/2023] Open
Abstract
Diabetic retinopathy (DR) is the leading cause of visual impairment in the working-age population of the Western world. The pathogenesis of DR is complex and several vascular, inflammatory, and neuronal mechanisms are involved. Inflammation mediates structural and molecular alterations associated with DR. However, the molecular mechanisms underlying the inflammatory pathways associated with DR are not completely characterized. Previous studies indicate that tissue hypoxia and dysregulation of immune responses associated with diabetes mellitus can induce increased expression of numerous vitreous mediators responsible for DR development. Thus, analysis of vitreous humor obtained from diabetic patients has made it possible to identify some of the mediators (cytokines, chemokines, and other factors) responsible for DR pathogenesis. Further studies are needed to better understand the relationship between inflammation and DR. Herein the main vitreous-related factors triggering the occurrence of retinal complication in diabetes are highlighted.
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Affiliation(s)
- F. Semeraro
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - A. Cancarini
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - R. dell'Omo
- Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy
| | - S. Rezzola
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - M. R. Romano
- Department of Neuroscience, Reproductive Sciences and Dentistry, University of Naples, Italy
| | - C. Costagliola
- Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy
- ICRRS Neuromed, Pozzilli, Isernia, Italy
- *C. Costagliola:
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CHOROIDAL THICKNESS CHANGES AFTER DIABETES TYPE 2 AND BLOOD PRESSURE CONTROL IN A HOSPITALIZED SITUATION. Retina 2014; 34:1190-8. [DOI: 10.1097/iae.0000000000000051] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Eshaq RS, Wright WS, Harris NR. Oxygen delivery, consumption, and conversion to reactive oxygen species in experimental models of diabetic retinopathy. Redox Biol 2014; 2:661-6. [PMID: 24936440 PMCID: PMC4052533 DOI: 10.1016/j.redox.2014.04.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 11/30/2022] Open
Abstract
Retinal tissue receives its supply of oxygen from two sources – the retinal and choroidal circulations. Decreases in retinal blood flow occur in the early stages of diabetes, with the eventual development of hypoxia thought to contribute to pathological neovascularization. Oxygen consumption in the retina has been found to decrease in diabetes, possibly due to either a reduction in neuronal metabolism or to cell death. Diabetes also enhances the rate of conversion of oxygen to superoxide in the retina, with experimental evidence suggesting that mitochondrial superoxide not only drives the overall production of reactive oxygen species, but also initiates several pathways leading to retinopathy, including the increased activity of the polyol and hexosamine pathways, increased production of advanced glycation end products and expression of their receptors, and activation of protein kinase C. Diabetes alters oxygen delivery and consumption in the retina. Conversion of oxygen to superoxide increases in the diabetic retina. An initial production of mitochondrial superoxide generates further ROS. ROS have been found to mediate deleterious pathways in the diabetic retina.
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Affiliation(s)
- Randa S Eshaq
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - William S Wright
- Department of Biomedical Sciences, University of South Carolina School of Medicine, Greenville, SC, USA
| | - Norman R Harris
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
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Reply. Retina 2014; 34:e10-1. [DOI: 10.1097/iae.0000000000000152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Wang H, Smith GW, Yang Z, Jiang Y, McCloskey M, Greenberg K, Geisen P, Culp WD, Flannery J, Kafri T, Hammond S, Hartnett ME. Short hairpin RNA-mediated knockdown of VEGFA in Müller cells reduces intravitreal neovascularization in a rat model of retinopathy of prematurity. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 183:964-74. [PMID: 23972394 DOI: 10.1016/j.ajpath.2013.05.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/29/2013] [Accepted: 05/06/2013] [Indexed: 02/08/2023]
Abstract
Vascular endothelial growth factor (VEGF) A is implicated in aberrant angiogenesis and intravitreous neovascularization (IVNV) in retinopathy of prematurity (ROP). However, VEGFA also regulates retinal vascular development and functions as a retinal neural survival factor. By using a relevant ROP model, the 50/10 oxygen-induced retinopathy (OIR) model, we previously found that broad inhibition of VEGFA bioactivity using a neutralizing antibody to rat VEGF significantly reduced IVNV area compared with control IgG but also significantly reduced body weight gain in the pups, suggesting an adverse effect. Therefore, we propose that knockdown of up-regulated VEGFA in cells that overexpress it under pathological conditions would reduce IVNV without affecting physiological retinal vascular development or overall pup growth. Herein, we determined first that the VEGFA mRNA signal was located within the inner nuclear layer corresponding to CRALBP-labeled Müller cells of pups in the 50/10 OIR model. We then developed a lentiviral-delivered miR-30eembedded shRNA against VEGFA that targeted Müller cells. Reduction of VEGFA by lentivector VEGFA-shRNAetargeting Müller cells efficiently reduced 50/10 OIR up-regulated VEGFA and IVNV in the model, without adversely affecting physiological retinal vascular development or pup weight gain. Knockdown of VEGFA in rat Müller cells by lentivector VEGFA-shRNA significantly reduced VEGFR2 phosphorylation in retinal vascular endothelial cells. Our results suggest that targeted knockdown of overexpressed VEGFA in Müller cells safely reduces IVNV in a relevant ROP model.
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Affiliation(s)
- Haibo Wang
- The John A. Moran Eye Center, The University of Utah, Salt Lake City, Utah, USA
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Bhat M, Pouliot M, Couture R, Vaucher E. The kallikrein-kinin system in diabetic retinopathy. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2014; 69:111-43. [PMID: 25130041 DOI: 10.1007/978-3-319-06683-7_5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetic retinopathy (DR) is a major microvascular complication associated with type 1 and type 2 diabetes mellitus, which can lead to visual impairment and blindness. Current treatment strategies for DR are mostly limited to laser therapies, steroids, and anti-VEGF agents, which are often associated with unwanted side effects leading to further complications. Recent evidence suggests that kinins play a primary role in the development of DR through enhanced vascular permeability, leukocytes infiltration, and other inflammatory mechanisms. These deleterious effects are mediated by kinin B1 and B2 receptors, which are expressed in diabetic human and rodent retina. Importantly, kinin B1 receptor is virtually absent in sane tissue, yet it is induced and upregulated in diabetic retina. These peptides belong to the kallikrein-kinin system (KKS), which contains two separate and independent pathways of regulated serine proteases, namely plasma kallikrein (PK) and tissue kallikrein (TK) that are involved in the biosynthesis of bradykinin (BK) and kallidin (Lys-BK), respectively. Hence, ocular inhibition of kallikreins or antagonism of kinin receptors offers new therapeutic avenues in the treatment and management of DR. Herein, we present an overview of the principal features and known inflammatory mechanisms associated with DR along with the current therapeutic approaches and put special emphasis on the KKS as a new and promising therapeutic target due to its link with key pathways directly associated with the development of DR.
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Leskova W, Watts MN, Carter PR, Eshaq RS, Harris NR. Measurement of retinal blood flow rate in diabetic rats: disparity between techniques due to redistribution of flow. Invest Ophthalmol Vis Sci 2013; 54:2992-9. [PMID: 23572104 DOI: 10.1167/iovs.13-11915] [Citation(s) in RCA: 20] [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 Reports of altered retinal blood flow in experimental models of type I diabetes have provided contrasting results, which leads to some confusion as to whether flow is increased or decreased. The purpose of our study was to evaluate early diabetes-induced changes in retinal blood flow in diabetic rats, using two distinctly different methods. METHODS Diabetes was induced by injection of streptozotocin (STZ), and retinal blood flow rate was measured under anesthesia by a microsphere infusion technique, or by an index of flow based on the mean circulation time between arterioles and venules. Measurements in STZ rats were compared to age-matched nondiabetic controls. In addition, the retinal distribution of fluorescently-labeled red blood cells (RBCs) was viewed by confocal microscopy in excised flat mounts. RESULTS Retinal blood flow rate was found to decrease by approximately 33% in the STZ rats compared to controls (P < 0.001) as assessed by the microsphere technique. However, in striking contrast, the mean circulation time through the retina was found to be almost 3× faster in the STZ rats (P < 0.01). This contradiction could be explained by flow redistribution through the superficial vessels of the diabetic retina, with this possibility supported by our observation of significantly fewer RBCs flowing through the deeper capillaries. CONCLUSIONS We conclude that retinal blood flow rate is reduced significantly in the diabetic rat, with a substantial decrease of flow through the capillaries due to shunting of blood through the superficial layer, allowing rapid transit from arterioles to venules.
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Affiliation(s)
- Wendy Leskova
- Louisiana State University Health Sciences Center in Shreveport, Department of Molecular and Cellular Physiology, Shreveport, LA 71130-3932, USA
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Abstract
Diabetic retinopathy remains the most common complication of diabetes mellitus and is a leading cause of visual loss in industrialized nations. The clinicopathology of the diabetic retina has been extensively studied, although the precise pathogenesis and cellular and molecular defects that lead to retinal vascular, neural and glial cell dysfunction remain somewhat elusive. This lack of understanding has seriously limited the therapeutic options available for the ophthalmologist and there is a need to identify the definitive pathways that initiate retinal cell damage and drive progression to overt retinopathy. The present review begins by outlining the natural history of diabetic retinopathy, the clinical features and risk factors. Reviewing the histopathological data from clinical specimens and animal models, the recent paradigm that neuroretinal dysfunction may play an important role in the early development of the disease is discussed. The review then focuses on the molecular pathogenesis of diabetic retinopathy with perspective provided on new advances that have furthered our understanding of the key mechanisms underlying early changes in the diabetic retina. Studies have also emerged in the past year suggesting that defective repair of injured retinal vessels by endothelial progenitor cells may contribute to the pathogenesis of diabetic retinopathy. We assess these findings and discuss how they could eventually lead to new therapeutic options for diabetic retinopathy.
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Vitreous mediators in retinal hypoxic diseases. Mediators Inflamm 2013; 2013:935301. [PMID: 23365490 PMCID: PMC3556845 DOI: 10.1155/2013/935301] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 10/19/2012] [Accepted: 12/01/2012] [Indexed: 12/31/2022] Open
Abstract
The causes of retinal hypoxia are many and varied. Under hypoxic conditions, a variety of soluble factors are secreted into the vitreous cavity including growth factors, cytokines, and chemokines. Cytokines, which usually serve as signals between neighboring cells, are involved in essentially every important biological process, including cell proliferation, inflammation, immunity, migration, fibrosis, tissue repair, and angiogenesis. Cytokines and chemokines are multifunctional mediators that can direct the recruitment of leukocytes to sites of inflammation, promote the process, enhance immune responses, and promote stem cell survival, development, and homeostasis. The modern particle-based flow cytometric analysis is more direct, stable and sensitive than the colorimetric readout of the conventional ELISA but, similar to ELISA, is influenced by vitreous hemorrhage, disruption of the blood-retina barrier, and high serum levels of a specific protein. Finding patterns in the expression of inflammatory cytokines specific to a particular disease can substantially contribute to the understanding of its basic mechanism and to the development of a targeted therapy.
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Brunner S, Binder S. Surgery for Proliferative Diabetic Retinopathy. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00111-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Miao X, Sun W, Miao L, Fu Y, Wang Y, Su G, Liu Q. Zinc and diabetic retinopathy. J Diabetes Res 2013; 2013:425854. [PMID: 23671870 PMCID: PMC3647550 DOI: 10.1155/2013/425854] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 02/08/2013] [Indexed: 02/02/2023] Open
Abstract
Zinc (Zn) is an important nutrient that is involved in various physiological metabolisms. Zn dyshomeostasis is often associated with various pathogeneses of chronic diseases, such as metabolic syndrome, diabetes, and related complications. Zn is present in ocular tissue in high concentrations, particularly in the retina and choroid. Zn deficiencies have been shown to affect ocular development, cataracts, age-related macular degeneration, and even diabetic retinopathy. However, the mechanism by which Zn deficiency increases the prevalence of diabetic retinopathy remains unclear. In addition, due to the negative effect of Zn deficiency on the eye, Zn supplementation should prevent diabetic retinopathy; however, limited available data do not always support this notion. Therefore, the goal of this paper was to summarize these pieces of available information regarding Zn prevention of diabetic retinopathy. Current theories and possible mechanisms underlying the role of Zn in the eye-related diseases are discussed. The possible factors that affect the preventive effect of Zn supplementation on diabetic retinopathy were also discussed.
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Affiliation(s)
- Xiao Miao
- The Second Hospital of Jilin University, Changchun 130021, China
- Department of Ophthalmology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
| | - Weixia Sun
- The First Hospital of Jilin University, Changchun 130021, China
| | - Lining Miao
- The Second Hospital of Jilin University, Changchun 130021, China
| | - Yaowen Fu
- The First Hospital of Jilin University, Changchun 130021, China
| | - Yonggang Wang
- The First Hospital of Jilin University, Changchun 130021, China
| | - Guanfang Su
- The Second Hospital of Jilin University, Changchun 130021, China
- Department of Ophthalmology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
- *Guanfang Su: and
| | - Quan Liu
- The First Hospital of Jilin University, Changchun 130021, China
- Department of Cardiovascular Disease, The First Hospital of Jilin University, Changchun, Jilin 130021, China
- *Quan Liu:
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Hein TW, Potts LB, Xu W, Yuen JZ, Kuo L. Temporal development of retinal arteriolar endothelial dysfunction in porcine type 1 diabetes. Invest Ophthalmol Vis Sci 2012; 53:7943-9. [PMID: 23139282 DOI: 10.1167/iovs.12-11005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Although hyperglycemia is implicated in retinal vascular dysfunction associated with the development of diabetic retinopathy, the temporal influence of hyperglycemia on retinal arteriolar reactivity remains unclear. Development of a large animal model of diabetes relevant to the human retina for evaluation of vascular function is also lacking. Herein, we examined nitric oxide (NO)-mediated dilation and endothelin-1 (ET-1)-induced constriction in retinal arterioles at various time periods in a porcine model of type 1 diabetes. METHODS Retinal arterioles were isolated from streptozocin-induced diabetic pigs (2, 6, and 12 weeks of hyperglycemia, 427 ± 23 mg/dL) and age-matched control pigs (73 ± 4 mg/dL), and then cannulated and pressurized for vasoreactivity study using videomicroscopic techniques. RESULTS Retinal arterioles isolated from control and diabetic pigs developed comparable levels of myogenic tone. The endothelium-dependent NO-mediated vasodilations to bradykinin and stepwise increases in luminal flow were significantly reduced within 2 weeks of hyperglycemia. The inhibitory effect was comparable following 6 and 12 weeks of hyperglycemia. However, the endothelium-independent vasodilation to sodium nitroprusside was unaffected. Constriction of retinal arterioles to ET-1 was unaltered at all time periods of hyperglycemia. CONCLUSIONS Our findings provide the first direct evidence for selective impairment of endothelium-dependent NO-mediated dilation of retinal arterioles within 2 weeks of hyperglycemia in a pig model of diabetes. By contrast, the ability of arteriolar smooth muscle to dilate to NO donor or contract to ET-1 was unaffected throughout the study period. This endothelial vasodilator dysfunction during early diabetes may contribute to development of retinopathy with chronic hyperglycemia.
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Affiliation(s)
- Travis W Hein
- Department of Surgery, Scott & White Memorial Hospital, College of Medicine, Texas A&M Health Science Center, Temple, Texas 76504, USA.
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Arden GB, Sivaprasad S. The pathogenesis of early retinal changes of diabetic retinopathy. Doc Ophthalmol 2012; 124:15-26. [PMID: 22302291 DOI: 10.1007/s10633-011-9305-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 12/14/2011] [Indexed: 01/04/2023]
Abstract
Recent successful trials of antibodies to vascular endothelial growth factor (VEGF) in diabetic retinopathy implicate this cytokine as a major cause of diabetic retinopathy (DR) and diabetic macular oedema (DME). The mechanisms which cause VEGF to be over-expressed to cause the vasculopathy are not entirely clear. This review explores the earliest changes to the retina in DR and the factors that predispose or prevent DR, including sleep apnoea, receptor degenerations laser treatment and VEGF polymorphism. The review also presents the evidence that retinal hypoxia, existing in the earliest stages, causes DR. This hypoxia is much increased by dark adaptation, indicating a new and possibly superior therapy.
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Wright WS, Singh Yadav A, McElhatten RM, Harris NR. Retinal blood flow abnormalities following six months of hyperglycemia in the Ins2(Akita) mouse. Exp Eye Res 2012; 98:9-15. [PMID: 22440813 PMCID: PMC3340465 DOI: 10.1016/j.exer.2012.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 02/13/2012] [Accepted: 03/05/2012] [Indexed: 12/30/2022]
Abstract
The aim of this study was to characterize the microvascular flow abnormalities and oxygenation changes that are present following six months of hyperglycemia in the diabetic Ins2(Akita) mouse. Previous studies have shown decreased retinal blood flow in the first several weeks of hyperglycemia in rodents, similar to the decreases seen in the early stages of human diabetes. However, whether this alteration in the mouse retina continues beyond the initial weeks of diabetes has yet to be determined, as are the potential consequences of the decreased flow on retinal oxygenation. In this study, male Ins2(Akita) and age-matched C57BL/6 (non-diabetic) mice were maintained for a period of six months, at which time intravital microscopy was used to measure retinal blood vessel diameters, blood cell velocity, vascular wall shear rates, blood flow rates, and transient capillary occlusions. In addition, the presence of hypoxia was assessed using the oxygen-sensitive probe pimonidazole. The diabetic retinal microvasculature displayed decreases in red blood cell velocity (30%, p<0.001), shear rate (25%, p<0.01), and flow rate (40%, p<0.001). Moreover, transient capillary stoppages in flow were observed in the diabetic mice, but rarely in the non-diabetic mice. However, no alterations were observed in retinal hypoxia as determined by a pimonidazole assay, suggesting the possibility that the decreases seen in retinal blood flow may be dictated by a decrease in retinal oxygen utilization.
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Affiliation(s)
- William S. Wright
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130
- Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, SC 29303
| | - Amit Singh Yadav
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130
| | - Robert M. McElhatten
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130
| | - Norman R. Harris
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130
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Yadav AS, Harris NR. Effect of tempol on diabetes-induced decreases in retinal blood flow in the mouse. Curr Eye Res 2011; 36:456-61. [PMID: 21501080 DOI: 10.3109/02713683.2011.556300] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE The purpose was to investigate the effect of the superoxide dismutase mimetic tempol on decreases in retinal blood flow that are found in diabetic mice. MATERIALS AND METHODS Streptozotocin (STZ) was injected into male C57BL/6 mice to induce hyperglycemia. One week following the STZ injection, subsets of the mice were given drinking water with or without 1 mM tempol for an additional three weeks. At the end of the four-week protocol, microvascular parameters were quantified via intravital microscopy, and included measurements of retinal diameters, red blood cell (RBC) velocities, blood flow rates, and wall shear rates. RESULTS Diabetes induced ~40-45% decreases in retinal blood flow rate (p < 0.001) four weeks following injection of STZ. The decrease in blood flow rate occurred with decreases in microvascular diameters (D) and RBC velocities (V). The average percentage decrease in velocity was greater than the percentage decrease in diameter and, therefore, wall shear rates (= 8 V/D) were ~25% lower in the diabetics than in the non-diabetics (p < 0.05). A three-week administration of tempol in the STZ mice allowed significantly higher blood flow rates than in the untreated STZ mice, with RBC velocities improved by the antioxidant (p < 0.05 on the venular side). However, tempol provided only moderate (and not statistically significant) improvements in wall shear rates. CONCLUSIONS The antioxidant tempol provides partial improvements in retinal microvascular hemodynamics early in the progression of STZ-induced diabetes in mice.
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Affiliation(s)
- Amit Singh Yadav
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
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CHANGES IN AREAS OF CAPILLARY NONPERFUSION AFTER INTRAVITREAL INJECTION OF BEVACIZUMAB IN EYES WITH BRANCH RETINAL VEIN OCCLUSION. Retina 2011; 31:1068-74. [DOI: 10.1097/iae.0b013e31820c83c2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Mariño C, Ortega M, Barreira N, Penedo MG, Carreira MJ, González F. Algorithm for registration of full Scanning Laser Ophthalmoscope video sequences. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2011; 102:1-16. [PMID: 21269727 DOI: 10.1016/j.cmpb.2010.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 11/04/2010] [Accepted: 12/01/2010] [Indexed: 05/30/2023]
Abstract
Fluorescein angiography is an established technique for examining the functional integrity of the retinal microcirculation for early detection of changes due to retinopathy. This paper describes a new method for the registration of large Scanning Laser Ophthalmoscope sequences (SLO), where the patient has been injected with a fluorescent dye. This allows the measurement of parameters such as the arteriovenous passage time. Due to the long time needed to acquire these sequences, there will inevitably be eye movement, which must be corrected prior to the application of quantitative analysis. The algorithm described here combines mutual information-based registration and landmark-based registration. The former will allow the alignment of the darkest frames of the sequence, where the dye has not still arrived to the retina, because of its ability to work with images without a preprocessing or segmentation, while the latter uses relevant features (the vessels) extracted by means of a robust creaseness operator, to get a very fast and accurate registration. The algorithm only detects rigid transformations but proves to be robust against the slight alterations derived from the eye location perspective during acquisition. Results were validated by expert clinicians.
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Affiliation(s)
- C Mariño
- Dep. Computación, Universidade da Coruña, Spain.
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Modulation of retinal blood flow by kinin B₁ receptor in Streptozotocin-diabetic rats. Exp Eye Res 2011; 92:482-9. [PMID: 21420952 DOI: 10.1016/j.exer.2011.03.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 02/22/2011] [Accepted: 03/08/2011] [Indexed: 11/20/2022]
Abstract
The vasoactive kinin B₁ receptor (B₁R) is overexpressed in the retina of diabetic rats in response to hyperglycemia and oxidative stress. The aim of the present study was to determine whether B₁R could contribute to the early retinal blood flow changes occurring in diabetes. Male Wistar rats were rendered diabetic with a single i.p. injection of Streptozotocin (STZ) and studied 4 days or 6 weeks after diabetes induction. The presence of B₁R in the retina was confirmed by Western blot. The impact of oral administration of the B₁R selective antagonist SSR240612 (10mg/kg) was measured on alteration of retinal perfusion in awake diabetic rats by quantitative autoradiography. Data showed that B₁R was upregulated in the STZ-diabetic retina at 4 days and 6 weeks. Retinal blood flow was not altered in 4-day diabetic rats compared with age-matched controls but was significantly decreased following SSR240612 treatment. In 6-week diabetic rats, retinal blood flow was markedly reduced compared to control rats and SSR240612 did not further decrease the blood flow. These results suggest that B₁R is upregulated in STZ-diabetic retina and has a protective compensatory role on retinal microcirculation at 4 days but not at 6 weeks following diabetes induction.
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Wright WS, McElhatten RM, Messina JE, Harris NR. Hypoxia and the expression of HIF-1alpha and HIF-2alpha in the retina of streptozotocin-injected mice and rats. Exp Eye Res 2009; 90:405-12. [PMID: 20005221 DOI: 10.1016/j.exer.2009.12.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 12/02/2009] [Accepted: 12/02/2009] [Indexed: 12/26/2022]
Abstract
Decreases in retinal blood flow in diabetics could render the retina hypoxic. In mouse and rat models of diabetes, a decrease in retinal blood flow occurs early, within 3-4 weeks of the induction of hyperglycemia, although information is scarce on whether this early decrease in flow induces hypoxia. The purpose of the current study was to determine whether hypoxia-inducible factor (HIF) levels increase following 4 and/or 12 weeks of hyperglycemia in streptozotocin (STZ)-injected mouse (C57BL/6) and rat (Wistar) retinas. Additionally, retinal tissue hypoxia was measured with pimonidazole following 12 weeks of hyperglycemia. These aims were accomplished via immunostaining of cross-sections from enucleated eyes. In mice, staining for HIF-1alpha and HIF-2alpha showed a contrasting pattern, with HIF-1alpha higher in the inner retina than outer, but HIF-2alpha higher in the outer retina than inner. However, in rats, staining for both HIF-1alpha and HIF-2alpha was more intense in the inner retina. The HIF-1alpha staining intensities and patterns were similar between diabetic animals and their non-diabetic counterparts following 4 and 12 weeks of hyperglycemia. The same was true for HIF-2alpha except for a trend toward an increase following 12 weeks of hyperglycemia in mice. Pimonidazole staining showed significant decreases throughout all layers of the central retina and most layers of the peripheral retina of rats (but not mice), following 12 weeks of hyperglycemia. In summary, despite early decreases in flow in rats and mice, retinal HIF-1alpha and HIF-2alpha were not found to be increased, and the extent of hypoxia may even decrease after 12 weeks of hyperglycemia in rats.
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Affiliation(s)
- William S Wright
- Department of Molecular and Cellular Physiology, Louisiana State University, Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
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Clapp C, Thebault S, Jeziorski MC, Martínez De La Escalera G. Peptide hormone regulation of angiogenesis. Physiol Rev 2009; 89:1177-215. [PMID: 19789380 DOI: 10.1152/physrev.00024.2009] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
It is now apparent that regulation of blood vessel growth contributes to the classical actions of hormones on development, growth, and reproduction. Endothelial cells are ideally positioned to respond to hormones, which act in concert with locally produced chemical mediators to regulate their growth, motility, function, and survival. Hormones affect angiogenesis either directly through actions on endothelial cells or indirectly by regulating proangiogenic factors like vascular endothelial growth factor. Importantly, the local microenvironment of endothelial cells can determine the outcome of hormone action on angiogenesis. Members of the growth hormone/prolactin/placental lactogen, the renin-angiotensin, and the kallikrein-kinin systems that exert stimulatory effects on angiogenesis can acquire antiangiogenic properties after undergoing proteolytic cleavage. In view of the opposing effects of hormonal fragments and precursor molecules, the regulation of the proteases responsible for specific protein cleavage represents an efficient mechanism for balancing angiogenesis. This review presents an overview of the actions on angiogenesis of the above-mentioned peptide hormonal families and addresses how specific proteolysis alters the final outcome of these actions in the context of health and disease.
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Affiliation(s)
- Carmen Clapp
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico.
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Abstract
Inner retinal ischaemia is involved in the pathogenesis of major vision-threatening diseases such as retinal vein thrombosis, diabetic retinopathy and retinopathy of prematurity. However, the pathogenesis of inner retinal ischaemia has not been fully elucidated, which represents an impediment to the development and improvement of techniques to prevent and treat these diseases on a rational basis. This paper provides a comprehensive review of current knowledge of the pathophysiology of inner retinal ischaemia, including clinical, anatomical and physiological aspects of disease development. It is suggested that chronic inner retinal ischaemia caused by capillary occlusion may develop secondary to an increase in hydrostatic pressure in the vessels. Further knowledge of the pathophysiology of inner retinal ischaemia can be obtained by identifying the mechanisms that lead to increased hydrostatic pressure in the capillary bed and establishing the structural and functional basis for the different response patterns in the central and peripheral areas of the retina that develop secondary to this increased hydrostatic pressure. Further elucidation of these unknown response patterns requires both in vitro and in vivo studies of retinal vascular pathophysiology. It is conceivable that a more detailed knowledge of these response patterns may help in the design of new treatments for retinal ischaemia and its vision-threatening consequences.
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Affiliation(s)
- Toke Bek
- Department of Ophthalmology, Arhus University Hospital, Arhus, Denmark.
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