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Bek T. Systemic risk factors contribute differently to the development of proliferative diabetic retinopathy and clinically significant macular oedema. Diabetologia 2020; 63:2462-2470. [PMID: 32696115 DOI: 10.1007/s00125-020-05234-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS The purpose of screening for diabetic retinopathy is to detect either of the two sight-threatening complications: proliferative diabetic retinopathy (PDR) or clinically significant diabetic macular oedema (DME). The aim of the study was to evaluate whether systemic risk factors affect the risk of developing these two complications differently. METHODS Survival analysis with death as a competing risk was used to describe the effect of sex, age and time of onset of diabetes, systolic (SBP) and diastolic (DBP) BPs, and the weighted exposure and CV of HbA1c for the development of PDR and DME from all 2773 patients treated for diabetic retinopathy in a defined population from the Aarhus area, Denmark, between 1 July 1994 and 1 July 2019. RESULTS Increasing HbA1c above normal increased the risk of developing both PDR and DME (p < 0.04), and values below normal increased the risk of developing PDR (p < 0.013). Increasing DBP increased the risk of developing both PDR and DME (p < 0.0001), whereas increasing SBP increased the risk of developing DME (p < 0.0001), but not PDR (p > 0.08). The risk of developing PDR increased with decreasing age of onset of diabetes (p < 0.0001), whereas the risk of developing DME was maximal for a known onset of diabetes at about 30 years of age and decreased significantly for both lower and higher ages of onset (p < 0.0001). The risk of developing both PDR and DME was lower in women than in men (p < 0.004) and was reduced with lower variability of repeated HbA1c measurements (p < 0.0001). CONCLUSIONS/INTERPRETATION Systemic risk factors such as metabolic regulation, arterial BP and the age of onset of diabetes contribute differently to the development of PDR and DME. The overall risk of developing treatment-requiring diabetic retinopathy should be calculated from the risks of reaching each of the two complications separately.
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Affiliation(s)
- Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, DK-8200, Aarhus N, Denmark.
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Bek T. Low educational level increases the incidence of vision-threatening diabetic retinopathy. Dan Med J 2020; 67:A03200181. [PMID: 33046211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
INTRODUCTION Diabetic retinopathy is defined as morphological lesions in the retina secondary to diabetes. The lesions may progress to a vision-threatening stage, which is more frequent in men and people with weak personal networks and a low psychosocial status. However, there is limited knowledge about the influence of other socio-economic factors on the development of treatment-requiring diabetic retinopathy. METHODS The number of patients from each postal district in the Aarhus County area who had been treated for diabetic retinopathy in the first eye between 1 July 1994 and 1 July 2019 was acquired. The standard information package "Key figures from postal districts" published 1 October 2019 by Statistics Denmark was used to study differences in treatment rates of diabetic retinopathy among postal districts and to explore to which extent such differences may be explained by population size, age, educational background and income. RESULTS During the study period of 25 years, 2,142 patients with home address in the former Aarhus County were treated for diabetic retinopathy. The treatment rate showed marked geographical variations and was inversely related to educational level, but was not independently related to either population size, age or income. CONCLUSIONS Initiatives aiming to reduce the incidence of treatment-requiring diabetic retinopathy in Danish healthcare should include preventive measures especially adapted to citizens with a low educational background. FUNDNG: none. TRIAL REGISTRATION not relevant.
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Jefsen OH, Petersen LV, Bek T, Østergaard SD. Is Early Blindness Protective of Psychosis or Are We Turning a Blind Eye to the Lack of Statistical Power? Schizophr Bull 2020; 46:1335-1336. [PMID: 32232391 PMCID: PMC7707070 DOI: 10.1093/schbul/sbaa048] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Oskar Hougaard Jefsen
- Psychiatric Research Academy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark,To whom correspondence should be addressed; tel: +45 30112066, e-mail:
| | - Liselotte Vogdrup Petersen
- The National Centre for Register-based Research, Aarhus University, Aarhus, Denmark,The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Aarhus, Denmark,Centre for Integrated Register-Based Research, Aarhus University, Aarhus, Denmark
| | - Toke Bek
- Department of Ophthalmology, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Søren Dinesen Østergaard
- Department of Affective Disorders, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Grauslund J, Andersen N, Andresen J, Flesner P, Haamann P, Heegaard S, Larsen M, Laugesen CS, Schielke K, Skov J, Bek T. Reply: Is automated screening for DR indeed not yet ready as stated by Grauslund et al? Acta Ophthalmol 2020; 98:e258. [PMID: 31536153 DOI: 10.1111/aos.14251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 01/14/2023]
Affiliation(s)
- Jakob Grauslund
- Danish Ophthalmological Society, Copenhagen, Denmark.,Department of Ophthalmology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Nis Andersen
- Danish Ophthalmological Society, Copenhagen, Denmark.,Organization of Danish Ophthalmologists, Copenhagen, Denmark
| | - Jens Andresen
- Danish Ophthalmological Society, Copenhagen, Denmark.,Organization of Danish Ophthalmologists, Copenhagen, Denmark
| | - Per Flesner
- Danish Ophthalmological Society, Copenhagen, Denmark.,Organization of Danish Ophthalmologists, Copenhagen, Denmark
| | - Per Haamann
- Danish Ophthalmological Society, Copenhagen, Denmark.,Organization of Danish Ophthalmologists, Copenhagen, Denmark
| | - Steffen Heegaard
- Danish Ophthalmological Society, Copenhagen, Denmark.,Department of Ophthalmology, Rigshospitalet, Copenhagen, Denmark
| | - Michael Larsen
- Danish Ophthalmological Society, Copenhagen, Denmark.,Department of Ophthalmology, Rigshospitalet, Copenhagen, Denmark
| | - Caroline Schmidt Laugesen
- Danish Ophthalmological Society, Copenhagen, Denmark.,Department of Ophthalmology, Zealand University Hospital Roskilde, Roskilde, Denmark
| | - Katja Schielke
- Danish Ophthalmological Society, Copenhagen, Denmark.,Department of Ophthalmology, Aalborg University Hospital, Aalborg, Denmark
| | - Jesper Skov
- Danish Ophthalmological Society, Copenhagen, Denmark.,Organization of Danish Ophthalmologists, Copenhagen, Denmark
| | - Toke Bek
- Danish Ophthalmological Society, Copenhagen, Denmark.,Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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55
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Affiliation(s)
- Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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56
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Tilma K, Bek T. Dilatation of Retinal Arterioles Induced by Topical Dorzolamide for One Week Is Impaired in Patients with Type 1 Diabetes and Mild Retinopathy. Ophthalmologica 2019; 243:236-242. [DOI: 10.1159/000504178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/15/2019] [Indexed: 11/19/2022]
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Dalby RB, Eskildsen SF, Videbech P, Frandsen J, Mouridsen K, Sørensen L, Jeppesen P, Bek T, Rosenberg R, Østergaard L. Oxygenation differs among white matter hyperintensities, intersected fiber tracts and unaffected white matter. Brain Commun 2019; 1:fcz033. [PMID: 32954272 PMCID: PMC7425421 DOI: 10.1093/braincomms/fcz033] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 08/27/2019] [Accepted: 10/01/2019] [Indexed: 01/15/2023] Open
Abstract
White matter hyperintensities of presumed vascular origin are frequently observed on magnetic resonance imaging in normal aging. They are typically found in cerebral small vessel disease and suspected culprits in the etiology of complex age- and small vessel disease-related conditions, such as late-onset depression. White matter hyperintensities may interfere with surrounding white matter metabolic demands by disrupting fiber tract integrity. Meanwhile, risk factors for small vessel disease are thought to reduce tissue oxygenation, not only by reducing regional blood supply, but also by impairing capillary function. To address white matter oxygen supply–demand balance, we estimated voxel-wise capillary density as an index of resting white matter metabolism, and combined estimates of blood supply and capillary function to calculate white matter oxygen availability. We conducted a cross-sectional study with structural, perfusion- and diffusion-weighted magnetic resonance imaging in 21 patients with late-onset depression and 21 controls. We outlined white matter hyperintensities and used tractography to identify the tracts they intersect. Perfusion data comprised cerebral blood flow, blood volume, mean transit time and relative transit time heterogeneity—the latter a marker of capillary dysfunction. Based on these, white matter oxygenation was calculated as the steady state cerebral metabolic rate of oxygen under the assumption of normal tissue oxygen tension and vice versa. The number, volume and perfusion characteristics of white matter hyperintensities did not differ significantly between groups. Hemodynamic data showed white matter hyperintensities to have lower blood flow and blood volume, but higher relative transit time heterogeneity, than normal-appearing white matter, resulting in either reduced capillary metabolic rate of oxygen or oxygen tension. Intersected tracts showed significantly lower blood flow, blood volume and capillary metabolic rate of oxygen than normal-appearing white matter. Across groups, lower lesion oxygen tension was associated with higher lesion number and volume. Compared with normal-appearing white matter, tissue oxygenation is significantly reduced in white matter hyperintensities as well as the fiber tracts they intersect, independent of parallel late-onset depression. In white matter hyperintensities, reduced microvascular blood volume and concomitant capillary dysfunction indicate a severe oxygen supply–demand imbalance with hypoxic tissue injury. In intersected fiber tracts, parallel reductions in oxygenation and microvascular blood volume are consistent with adaptations to reduced metabolic demands. We speculate, that aging and vascular risk factors impair white matter hyperintensity perfusion and capillary function to create hypoxic tissue injury, which in turn affect the function and metabolic demands of the white matter tracts they disrupt.
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Affiliation(s)
- Rikke B Dalby
- Center of Functionally Integrative Neuroscience & MINDLab, Aarhus University Hospital, 8200 Aarhus C., Denmark.,Centre for Psychiatric Research, Aarhus University Hospital, 8340 Risskov, Denmark.,Department of Neuroradiology, Aarhus University Hospital, 8200 Aarhus N., Denmark
| | - Simon F Eskildsen
- Center of Functionally Integrative Neuroscience & MINDLab, Aarhus University Hospital, 8200 Aarhus C., Denmark
| | - Poul Videbech
- Center for Neuropsychiatric Depression Research, Mental Health Center Glostrup, 2600 Glostrup, Denmark
| | - Jesper Frandsen
- Center of Functionally Integrative Neuroscience & MINDLab, Aarhus University Hospital, 8200 Aarhus C., Denmark
| | - Kim Mouridsen
- Center of Functionally Integrative Neuroscience & MINDLab, Aarhus University Hospital, 8200 Aarhus C., Denmark
| | - Leif Sørensen
- Department of Neuroradiology, Aarhus University Hospital, 8200 Aarhus N., Denmark
| | - Peter Jeppesen
- Department of Ophthalmology, Aarhus University Hospital, 8200 Aarhus N., Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, 8200 Aarhus N., Denmark
| | - Raben Rosenberg
- Centre of Psychiatry Amager, Mental Health Services in the Capital Region of Denmark, 2300 Copenhagen S., Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience & MINDLab, Aarhus University Hospital, 8200 Aarhus C., Denmark.,Department of Neuroradiology, Aarhus University Hospital, 8200 Aarhus N., Denmark
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58
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Jørgensen M, Savran MM, Christakopoulos C, Bek T, Grauslund J, Toft PB, Ziemssen F, Konge L, Sørensen TL, Subhi Y. Development and validation of a multiple-choice questionnaire-based theoretical test in direct ophthalmoscopy. Acta Ophthalmol 2019; 97:700-706. [PMID: 30816642 DOI: 10.1111/aos.14065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 02/02/2019] [Indexed: 12/17/2022]
Abstract
PURPOSE Direct ophthalmoscopy can reveal systemic, neurologic and ophthalmic conditions, but is poorly mastered among young physicians. A theoretical test is needed to measure effect of educational interventions. We developed and gathered validity evidence for a multiple-choice questionnaire (MCQ)-based theoretical test in direct ophthalmoscopy. METHODS The MCQ was developed by interviewing experts. Then, validity evidence was evaluated using Messick's validity framework. Content was ensured by inviting the experts to contribute in a Delphi-like process. Response process was ensured by piloting and by streamlining all instructions. Then, the test was taken by ophthalmologists and by medical students without experience in direct ophthalmoscopy. Results were used to evaluate internal structure (item quality analysis and internal consistency), relations to other variables (correlation of test scores to experience level) and consequences (establishment of pass-fail score and the consequences of its use). RESULTS The first phase of the study yielded 100 MCQs. In second phase, we identified that 60 items fulfilled predefined relevance and item quality requirements. These items demonstrated very high internal consistency (Cronbach's alpha = 0.95), significantly discriminated medical students from specialists (p < 0.001, independent samples t-test) and the established pass-fail score of 50 (83%) correct answers resulted in no false positives (students passing) and no false negatives (specialists failing). A Decision study identified that sampling 15 items suffice for certification. CONCLUSION We developed and validated an MCQ-based theoretical test in direct ophthalmoscopy that enables an evidence-based approach to measuring, evaluating and certifying the theoretical knowledge necessary for direct ophthalmoscopy.
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Affiliation(s)
- Morten Jørgensen
- Department of Ophthalmology Zealand University Hospital Roskilde Denmark
- CAMES – Copenhagen Academy for Medical Education and Simulation Capital Region of Denmark Copenhagen Denmark
- Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Mona Meral Savran
- CAMES – Copenhagen Academy for Medical Education and Simulation Capital Region of Denmark Copenhagen Denmark
- Department of Obstetrics and Gynaecology Copenhagen University Hospital Amager and Hvidovre Hvidovre Denmark
| | | | - Toke Bek
- Department of Ophthalmology Aarhus University Hospital Aarhus Denmark
| | - Jakob Grauslund
- Department of Ophthalmology Odense University Hospital Odense Denmark
- Department of Clinical Research Faculty of Healthy Science University of Southern Denmark Odense Denmark
| | - Peter Bjerre Toft
- Department of Ophthalmology, Rigshospitalet Copenhagen University Hospital Copenhagen Denmark
| | - Focke Ziemssen
- Center for Ophthalmology Eberhard‐Karl University Tübingen Tübingen Germany
| | - Lars Konge
- CAMES – Copenhagen Academy for Medical Education and Simulation Capital Region of Denmark Copenhagen Denmark
- Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Torben Lykke Sørensen
- Department of Ophthalmology Zealand University Hospital Roskilde Denmark
- Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Yousif Subhi
- Department of Ophthalmology Zealand University Hospital Roskilde Denmark
- Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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Petersen L, Bek T. Retinal vasodilatation in the affected eye but reduced pressure autoregulation of both eyes in unilateral Coats' disease. Acta Ophthalmol 2019; 97:679-683. [PMID: 30840364 DOI: 10.1111/aos.14073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 02/02/2019] [Indexed: 11/26/2022]
Abstract
BACKGROUND Coats' disease is characterized by vascular hyperpermeability, oedema and accumulation of exudates related to impairment of retinal vascular function. The background for the development of the disease is unknown, but it is likely that the study of diameter changes of retinal vessels may contribute to understanding the pathophysiology of the disease. METHODS In seven patients with unilateral Coats' disease (mean age = 34.7 years, range: 11-69 years), the baseline diameter and reactivity of retinal vessels during an increase in the arterial blood pressure by isometric exercise and in the metabolism by flicker stimulation were measured on video recordings of the retina obtained with the Dynamic Vessel Analyzer. RESULTS The baseline diameter of retinal vessels was larger in the affected than in the unaffected eyes which was significant for the arterioles (p = 0.02), but not for the venules (p = 0.15). During an increase in the arterial blood pressure induced by isometric exercise, the normal contraction of arterioles was absent in both eyes (p > 0.7), whereas there was a significant dilatation of the venules in the unaffected eyes (p = 0.04). Stimulation with flickering light induced normal dilatation of retinal vessels in both affected and unaffected eyes. CONCLUSION Unilateral Coats' disease is accompanied by vasodilatation in the affected eye but impaired pressure autoregulation in both eyes. A further investigation of the disease should include an elucidation of the background for dilatation of retinal vessels in affected eyes and whether impaired pressure autoregulation can be found in vessels elsewhere in the body.
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Affiliation(s)
- Line Petersen
- Department of Ophthalmology Aarhus University Hospital Aarhus C Denmark
| | - Toke Bek
- Department of Ophthalmology Aarhus University Hospital Aarhus C Denmark
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60
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Freund SS, Stoltz RK, Bek T, Keller J, Baad-Hansen T. [Purtscher's retinopathy as a complication to a cemented resection tumour prosthesis]. Ugeskr Laeger 2019; 181:V02190096. [PMID: 31791468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this case report, a 53-year-old female with a pathological subtrochanteric femur fracture received a cemented resection tumour prosthesis. The patient was post-operatively diagnosed with Purtscher's retinopathy due to fat embolisation. Purtscher's retinopathy has previously been described in trauma patients, however, no previous reports exist with patients treated with prosthesis. No treatment guideline is available. There is a risk of permanent visual impairment, and it is recommended, that patients presenting reduced vision post-operatively are referred to an ophthalmologist without delay for correct diagnosis.
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Petersen L, Bek T. The Oxygen Saturation in Vascular Abnormalities Depends on the Extent of Arteriovenous Shunting in Diabetic Retinopathy. ACTA ACUST UNITED AC 2019; 60:3762-3767. [DOI: 10.1167/iovs.19-27472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Line Petersen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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Baier JM, Funck KL, Petersen L, Vernstrøm L, Knudsen ST, Bek T, Poulsen PL, Laugesen E. Retinal vessel reactivity is not attenuated in patients with type 2 diabetes compared with matched controls and is associated with peripheral endothelial function in controls. J Diabetes Complications 2019; 33:641-647. [PMID: 31270030 DOI: 10.1016/j.jdiacomp.2019.05.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/22/2019] [Accepted: 05/27/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND AIMS Attenuated retinal vasoreactivity in patients with type 2 diabetes preceding diabetic retinopathy development has been proposed to reflect local endothelial dysfunction. Whether retinal vessel reactivity is associated with peripheral endothelial dysfunction and large artery stiffness in patients with type 2 diabetes remains to be elucidated. METHODS Twenty patients with type 2 diabetes without retinopathy and 20 sex- and age matched controls (diabetes duration: 9.9 years (range 6.0;12.4), 40% male, age: 66.5 ± 7.3 (diabetes) and 65.2 ± 7.6 years (controls)) were included. Endothelial function was assessed using EndoPAT. Arterial stiffness was assessed by carotid-femoral pulse wave velocity using the SphygmoCor. Retinal blood supply regulation was examined by retinal arteriolar diameter change during 1) isometric exercise (hand-weight lifting), 2) exposure to flickering lights, and 3) a combined stimulus of 1) + 2) using the Dynamic Vessel Analyzer. RESULTS No significant differences were observed in retinal vessel reactivity in T2DM patients compared to controls. Endothelial function was associated with mean arteriolar diameter change during only the combination intervention, (Beta = 0.033 [0.0013;0.064], p = 0.042) in the overall population of patients and controls. When groups were analyzed separately, the associations was statistically significant only in controls. However, formal test for interaction was not statistically significant, p = 0.40. No association was observed between pulse wave velocity and retinal arteriolar %-diameter change in patients or controls. CONCLUSION Peripheral endothelial function was associated with retinal arteriolar diameter change in the combined sample. The association seemed to be driven primarily by the controls. Our findings indicate that peripheral endothelial function is reflective of endothelial function in the retina mainly in subjects without T2DM, whereas an association in T2DM without retinopathy was not observed. Further studies are needed in T2DM patients with more advanced retinopathy.
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Affiliation(s)
- Jonathan Mathias Baier
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, DK-8200, Denmark.
| | - Kristian Løkke Funck
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, DK-8200, Denmark.
| | - Line Petersen
- Department of Ophthalmology, Aarhus University Hospital, DK-8200, Denmark.
| | - Liv Vernstrøm
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, DK-8200, Denmark.
| | - Søren T Knudsen
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, DK-8200, Denmark.
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, DK-8200, Denmark.
| | - Per Løgstrup Poulsen
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, DK-8200, Denmark.
| | - Esben Laugesen
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, DK-8200, Denmark.
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Abstract
The clinical presentation of the most frequent vision threatening retinal diseases is dominated by lesions indicating that disturbances in retinal blood flow are involved in the pathogenesis of these diseases. The present review describes the experience from a translational strategy pursued to investigate retinal vascular diseases with diabetic retinopathy as the main object. The normal regulation of retinal blood flow is investigated in porcine retinal vessels in vitro and ex vivo. Subsequently, the in vitro findings are translated to clinical studies in normal persons in vivo, and it is investigated whether the mechanisms are disturbed in retinal vascular disease. This is followed by clinical intervention studies on these diseases. The approach has been used to investigate pressure autoregulation, metabolic autoregulation and vasomotion in retinal vessels. The investigations have shown that retinal vascular tone can be regulated by receptor-specific agonists and antagonists to vasoactive compounds such as purines, prostaglandins and nitric oxide synthesis and that the vasoactive effects can be modulated by the concentration and the mode of administration of these compounds. Additionally, it has been shown that retinal precapillary arterioles and capillaries not visible by ophthalmoscopy may play an important role for the pathophysiology of retinal vascular disease and its treatment. Future studies should focus on investigating normal and pathological regulation of retinal blood flow in these smaller vessels.
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Affiliation(s)
- Toke Bek
- Department of Ophthalmology Aarhus University Hospital Aarhus C DK‐8000 Denmark
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El Dabagh Y, Petersen L, Pedersen M, Bek T. Reduced baseline diameter and contraction of peripheral retinal arterioles immediately after remote ischemia in diabetic patients. Graefes Arch Clin Exp Ophthalmol 2019; 257:2095-2101. [PMID: 31273510 DOI: 10.1007/s00417-019-04407-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/24/2019] [Accepted: 06/27/2019] [Indexed: 01/14/2023] Open
Abstract
PURPOSE Remote ischemic conditioning (RIC) implies that transient ischemia in one organ can affect blood flow and protect from ischemia in another remote organ such as the retina. The purpose of the present study was to investigate the effect of RIC on the diameter of retinal arterioles in patients with diabetic retinopathy and whether this effect differs among peripheral and macular vessels. METHODS In twenty type 1 diabetes patients aged 20-31 years, the Dynamic Vessel Analyzer (DVA) was used to measure diameters of peripheral and macular arterioles during rest, isometric exercise, and flicker stimulation. Measurements were obtained before, immediately after, and 1 h after RIC, and were compared to responses obtained from normal persons. RESULTS The reduced baseline diameter (p < 0.009) and contraction of peripheral retinal arterioles during isometric exercise (p = 0.025) observed immediately after RIC in normal persons were absent in the studied diabetic patients. CONCLUSIONS RIC affects the diameter of peripheral but not macular arterioles in normal persons, but the response is abolished in diabetic patients. TRIAL REGISTRATION NCT03906383.
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Affiliation(s)
- Yasmin El Dabagh
- Department of Ophthalmology, Aarhus University Hospital, 8200, Aarhus N, Denmark.
- Comparative Medicine Laboratory, Department of Clinical Medicine, Aarhus University Hospital, 8200, Aarhus N, Denmark.
| | - Line Petersen
- Department of Ophthalmology, Aarhus University Hospital, 8200, Aarhus N, Denmark
| | - Michael Pedersen
- Comparative Medicine Laboratory, Department of Clinical Medicine, Aarhus University Hospital, 8200, Aarhus N, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, 8200, Aarhus N, Denmark
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Dons-Jensen A, Petersen L, Bøtker HE, Bek T. The Diameter of Retinal Arterioles Is Unaffected by Intravascular Administration of the Adenosine A 2A Receptor Agonist Regadenoson in Normal Persons. Biomed Hub 2019; 4:1-10. [PMID: 31993423 PMCID: PMC6985886 DOI: 10.1159/000500563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/14/2019] [Indexed: 12/31/2022] Open
Abstract
Background The neurotransmitter adenosine has been proposed to be involved in the pathogenesis of diabetic retinopathy, which may be due to the vasoactive properties of the compound. Previous studies have shown that adenosine can affect the tone of retinal arterioles in vitro to induce dilatation mediated by A<sub>2A</sub> and A<sub>2B</sub>receptors and constriction mediated by A<sub>1</sub> and A<sub>3</sub> receptors. Purpose To investigate effects of intravenous administration of the adenosine A<sub>2A</sub> receptor agonist regadenoson on the diameter of retinal vessels in vivo. Method The diameter responses of larger retinal arterioles and venules were evaluated using the dynamic vessel analyser in 20 normal persons (age 22–31 years) after intravenous administration of the adenosine A<sub>2A</sub> receptor agonist regadenoson during exposure to systemic normoxia and hypoxia. Results The diameter of retinal arterioles and venules increased significantly during stimulation with flickering light (p < 0.0001). Regadenoson reduced the flicker-induced dilatation of venules during normoxia (p = 0.0006), but otherwise had no effect on vessel diameters (p > 0.08 for all comparisons). Conclusions Intravenous administration of the adenosine A<sub>2A</sub> receptor agonist regadenoson had no significant effect on the diameter of retinal arterioles. Future studies should investigate differential effects of intra- and extravascular administration of adenosine receptor agonists on retinal vessels.
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Affiliation(s)
- Anna Dons-Jensen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Line Petersen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Hans-Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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Simonsen U, Winther AK, Oliván-Viguera A, Comerma-Steffensen S, Köhler R, Bek T. Extracellular l-arginine Enhances Relaxations Induced by Opening of Calcium-Activated SKCa Channels in Porcine Retinal Arteriole. Int J Mol Sci 2019; 20:ijms20082032. [PMID: 31027156 PMCID: PMC6515554 DOI: 10.3390/ijms20082032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 01/27/2023] Open
Abstract
We investigated whether the substrate for nitric oxide (NO) production, extracellular l-arginine, contributes to relaxations induced by activating small (SKCa) conductance Ca2+-activated potassium channels. In endothelial cells, acetylcholine increased 3H-l-arginine uptake, while blocking the SKCa and the intermediate (IKCa) conductance Ca2+-activated potassium channels reduced l-arginine uptake. A blocker of the y+ transporter system, l-lysine also blocked 3H-l-arginine uptake. Immunostaining showed co-localization of endothelial NO synthase (eNOS), SKCa3, and the cationic amino acid transporter (CAT-1) protein of the y+ transporter system in the endothelium. An opener of SKCa channels, cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA) induced large currents in endothelial cells, and concentration-dependently relaxed porcine retinal arterioles. In the presence of l-arginine, concentration-response curves for CyPPA were leftward shifted, an effect unaltered in the presence of low sodium, but blocked by l-lysine in the retinal arterioles. Our findings suggest that SKCa channel activity regulates l-arginine uptake through the y+ transporter system, and we propose that in vasculature affected by endothelial dysfunction, l-arginine administration requires the targeting of additional mechanisms such as SKCa channels to restore endothelium-dependent vasodilatation.
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Affiliation(s)
- Ulf Simonsen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Wilhelm Meyers Allé 4, DK-8000 Aarhus C, Denmark.
| | - Anna K Winther
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Wilhelm Meyers Allé 4, DK-8000 Aarhus C, Denmark.
| | - Aida Oliván-Viguera
- BESICoS group, Aragón Institute of Engineering Research, IIS-Aragón, University of Zaragoza, 50009 Zaragoza, Spain.
| | - Simon Comerma-Steffensen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Wilhelm Meyers Allé 4, DK-8000 Aarhus C, Denmark.
| | - Ralf Köhler
- Aragón Agency for Research and Development (ARAID) at IACS and IIS Aragón, 50009 Zaragoza, Spain.
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, DK-8000 Aarhus C, Denmark.
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Madsen LR, Bek T, Richelsen B. Diabetic retinopathy in people with Type 2 diabetes and obesity treated by Roux-en-Y gastric bypass compared with non-operated controls: with focus on the role of diabetes remission in a cross-sectional and a 6-year follow-up study. Diabet Med 2019; 36:457-464. [PMID: 30537170 DOI: 10.1111/dme.13876] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 12/01/2022]
Abstract
AIM Whether or not Roux-en-Y gastric bypass (RYGB) and the derived metabolic improvements are beneficial to diabetic retinopathy is controversial. We aimed to determine the presence and development of retinopathy in individuals with obesity and Type 2 diabetes treated by RYGB compared with non-operated controls, and to determine the role of diabetes remission. METHODS We graded fundus photography using the Wisconsin Epidemiologic Study of Diabetic Retinopathy in 96 individuals with obesity and Type 2 diabetes treated by RYGB 6 years after surgery compared with 48 non-operated controls. In a subsample, we investigated the development of retinopathy over time. In the secondary analysis, we divided the RYGB group according to diabetes remission. RESULTS RYGB surgery was not statistically associated with less retinopathy [relative risk (RR) 0.82, 95% CI 0.59 to 1.14], when adjusted for diabetes duration, sex, age and BMI. During 5.9 years of follow-up, retinopathy grading in the RYGB group was unchanged, whereas the control group displayed worse grading by 0.69 steps (95% CI 0.18 to 1.19). The RYGB group with diabetes remission (52%) showed a trend towards less retinopathy [adjusted RR (aRR) 0.45; 95% CI 0.19 to 1.06] than controls, and less retinopathy (aRR 0.33; 95% CI 0.11 to 0.94) than the RYGB group without remission in the cross-sectional data. CONCLUSIONS In a cross-sectional setting, individuals with Type 2 diabetes treated by RYGB showed a tendency towards less retinopathy than non-operated controls, in particular diabetes remission following RYGB was associated with less retinopathy. Moreover after 5.9 years, retinopathy in the RYGB group had progressed less than in the control group. (Clinical Trial Registry No: NCT02625649).
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Affiliation(s)
- L R Madsen
- Department of Endocrinology and Internal Medicine, Aarhus University, Aarhus, Denmark
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - T Bek
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - B Richelsen
- Department of Endocrinology and Internal Medicine, Aarhus University, Aarhus, Denmark
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
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68
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Davidsen RS, Hemanth S, Keller SS, Bek T, Hansen O. Evaluation of the capacitive behavior of 3D carbon electrodes for sub-retinal photovoltaic prosthesis. Micro and Nano Engineering 2019. [DOI: 10.1016/j.mne.2019.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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69
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Askou AL, Alsing S, Benckendorff JNE, Holmgaard A, Mikkelsen JG, Aagaard L, Bek T, Corydon TJ. Suppression of Choroidal Neovascularization by AAV-Based Dual-Acting Antiangiogenic Gene Therapy. Mol Ther Nucleic Acids 2019; 16:38-50. [PMID: 30825671 PMCID: PMC6393707 DOI: 10.1016/j.omtn.2019.01.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/28/2019] [Accepted: 01/28/2019] [Indexed: 01/15/2023]
Abstract
Vascular endothelial growth factor A (VEGFA) is involved in the pathogenesis of vasoproliferative retinal diseases, such as exudative age-related macular degeneration (AMD). The objective of this study was to investigate whether dual-acting therapy based on the simultaneous expression of anti-VEGFA microRNAs (miRNAs) and the secreted, antiangiogenic protein pigment endothelial-derived factor (PEDF) delivered by adeno-associated virus (AAV) vectors provides improved protection against choroidal neovascularization (CNV). To investigate this, a multigenic AAV vector allowing retina pigment epithelium (RPE)-specific expression of anti-VEGFA miRNAs and PEDF was engineered. Robust expression of PEDF, driven by the RPE-specific vitelliform macular dystrophy 2 promoter, was observed in human cells and in mouse retina. A significant reduction in CNV was observed in a laser-induced CNV mouse model 57 days post-injection of the AAV5 particles conveying either anti-VEGFA miRNA and PEDF dual therapy or anti-VEGFA miRNA monotherapy. Overall, CNV reduction was most prominent in animals receiving dual-acting therapy. In both cases, the reduction in CNV was accompanied by a significant attenuation of VEGFA. In conclusion, the presented data reveal that gene therapy targeting VEGFA via multigenic AAV vectors displays combined efficacy, suggesting that dual-acting therapy is an important tool in future eye gene therapy for the treatment of neovascular ocular diseases, including AMD.
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Affiliation(s)
- Anne Louise Askou
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Sidsel Alsing
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Andreas Holmgaard
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Lars Aagaard
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark
| | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
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70
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Grauslund J, Andersen N, Andresen J, Flesner P, Haamann P, Heegaard S, Larsen M, Laugesen CS, Schielke K, Skov J, Bek T. Evidence-based Danish guidelines for screening of diabetic retinopathy. Acta Ophthalmol 2018; 96:763-769. [PMID: 30311394 DOI: 10.1111/aos.13936] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/14/2018] [Indexed: 01/06/2023]
Abstract
PURPOSE Diabetic retinopathy (DR) is among the leading causes of visual loss in the working-age population. It is generally accepted that screening of DR is cost-effective and can detect DR before it becomes sight-threatening to allow timely treatment. METHODS A group of retinal specialists was formed by the Danish Ophthalmological Society with the aim to formulate contemporary evidence-based guidelines for screening of DR in order to implement these in the Danish screening system. RESULTS We hereby present evidence for DR-screening regarding (1) classification of DR, (2) examination techniques, (3) screening intervals and (4) automated screening. It is our recommendation that the International Clinical Retinopathy Disease Severity Scale should be used to classify DR. As a minimum, mydriatic two-field disc- and macular-centred images are required. In the case of suspected clinically significant diabetic macular oedema, supplementary optical coherence tomography can increase the diagnostic accuracy. There is solid evidence to support a flexible, individualized screening regimen. In particular, it is possible to prolong screening intervals to 24-48 months for patients with no or mild nonproliferative diabetic retinopathy (NPDR), but it is also possible to use extended intervals of 12-24 months for patients with moderate NPDR given that these are well-regulated regarding glycaemic control (HbA1c ≤ 53 mmol/mol) and blood pressure (≤130/80 mmHg). Automated screening of DR is encouraging but is not ready for implementation at present. CONCLUSION Danish evidenced-based guidelines for screening of DR support high-quality imaging and allow flexible, individualized screening intervals with a potential for extension to patients with low risk of DR progression.
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Affiliation(s)
- Jakob Grauslund
- Danish Ophthalmological Society; Copenhagen Denmark
- Department of Ophthalmology; Odense University Hospital; Odense Denmark
- Department of Clinical Research; University of Southern Denmark; Odense Denmark
| | - Nis Andersen
- Danish Ophthalmological Society; Copenhagen Denmark
- Organization of Danish Ophthalmologists; Copenhagen Denmark
| | - Jens Andresen
- Danish Ophthalmological Society; Copenhagen Denmark
- Organization of Danish Ophthalmologists; Copenhagen Denmark
| | - Per Flesner
- Danish Ophthalmological Society; Copenhagen Denmark
- Organization of Danish Ophthalmologists; Copenhagen Denmark
| | - Per Haamann
- Danish Ophthalmological Society; Copenhagen Denmark
- Organization of Danish Ophthalmologists; Copenhagen Denmark
| | - Steffen Heegaard
- Danish Ophthalmological Society; Copenhagen Denmark
- Department of Ophthalmology; Rigshospitalet-Glostrup; Copenhagen Denmark
| | - Michael Larsen
- Danish Ophthalmological Society; Copenhagen Denmark
- Department of Ophthalmology; Rigshospitalet-Glostrup; Copenhagen Denmark
| | - Caroline Schmidt Laugesen
- Danish Ophthalmological Society; Copenhagen Denmark
- Department of Ophthalmology; Zealand University Hospital Roskilde; Roskilde Denmark
| | - Katja Schielke
- Danish Ophthalmological Society; Copenhagen Denmark
- Department of Ophthalmology; Aalborg University Hospital; Aalborg Denmark
| | - Jesper Skov
- Danish Ophthalmological Society; Copenhagen Denmark
- Organization of Danish Ophthalmologists; Copenhagen Denmark
| | - Toke Bek
- Danish Ophthalmological Society; Copenhagen Denmark
- Department of Ophthalmology; Aarhus University Hospital; Aarhus Denmark
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71
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Jensen PS, Aalkjaer C, Bek T. The vasodilating effect of glucose differs among vessels at different branching level in the porcine retina ex vivo. Exp Eye Res 2018; 179:150-156. [PMID: 30419216 DOI: 10.1016/j.exer.2018.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/16/2018] [Accepted: 11/06/2018] [Indexed: 02/06/2023]
Abstract
Diabetic retinopathy is characterized by retinal lesions related to disturbances in retinal blood flow. The metabolic dysregulation in diabetes involves hyperglycemia which in both clinical and experimental studies has been shown to induce dilatation of larger retinal vessels, which has been suggested to be mediated by nitric oxide (NO). However, the effects of glucose on the diameter of smaller retinal vessels that are the site of development of diabetic retinopathy are unknown. Diameter changes in porcine retinal arterioles, pre-capillary arterioles and capillaries were studied ex vivo during acute changes in intraluminal glucose concentrations that mimicked changes in plasma glucose in diabetic patients. The experiments were repeated during blocking of NO-synthesis. Intravascular application of 2 mM glucose dilated arterioles and capillaries significantly, while 20 mM glucose dilated precapillary arterioles significantly. Intravascular application of 20 mM glucose dilated precapillary arterioles previously exposed to 2 mM glucose, while no significant diameter changes were observed after application of 2 mM glucose in vessels previously exposed to 20 mM glucose. No diameter changes were observed after application of 5.5 mM glucose in vessels previously exposed to both 2 mM and 20 mM glucose in either order. There was no significant difference between the diameter responses in the absence and presence of NO-synthesis blocker. Glucose induced dilatation of porcine precapillary arterioles ex vivo differs from the response in larger arterioles and capillaries, and the response is unaffected by the blocking of NO-synthesis. This may have implications for understanding the pathophysiology of diseases in the retinal microcirculation, such as diabetic retinopathy.
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Affiliation(s)
- Peter Skov Jensen
- Department of Ophthalmology, Aarhus University Hospital, DK-8000, Aarhus C, Denmark.
| | - Christian Aalkjaer
- Department of Biomedicine (physiology), University of Aarhus, DK-8000, Aarhus C, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, DK-8000, Aarhus C, Denmark
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72
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Jakobsen NS, Larsen DA, Bek T. The area of fixation covaries with short-term changes in visual acuity after anti-vascular endothelial growth factor treatment in patients with diabetic macular oedema. Acta Ophthalmol 2018; 96:744-748. [PMID: 29687595 DOI: 10.1111/aos.13773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/04/2018] [Indexed: 12/01/2022]
Abstract
PURPOSE Diabetic maculopathy can be treated with intravitreal injection of vascular endothelial growth factor (VEGF) inhibitors. However, the therapy is not effective in all patients, and it would be desirable to have parameters for differentiating patients who will benefit from treatment from those who will not. Retinal fixation has been shown to be impaired in patients with low visual acuity (VA) secondary to macular disease, but the changes in fixational eye movements after anti-VEGF treatment for diabetic maculopathy have not been investigated. METHODS Retinal fixation was studied in 29 patients with diabetic macular oedema before three monthly anti-VEGF injections, and 1 and 4 months after the last injection. The change in VA was correlated with changes in area, frequency, amplitude and total number of fixational saccades. RESULTS During three monthly injections, best-corrected visual acuity (BCVA) increased from (mean ± SD) 74.0 ± 11.5 Early Treatment Diabetic Retinopathy Study (ETDRS) letters to 78.3 ± 9.8 ETDRS letters, (p = 0.003) and central retinal thickness (CRT) decreased from (mean ± SD) 441.7 ± 107.0 μm to 339.5 ± 74.2 μm, (p = <0.0001), which was followed by the opposite changes after treatment (BCVA reduced nonsignificantly to 77.5 ± 10.4 ETDRS letters (p = 0.06), and CRT increased to 393.0 ± 9.8 μm, p = <0.0001). Both improvement and worsening of BCVA correlated with the fixation area (r2 = 0.28, p = 0.003 and r2 = 0.14, p = 0.045, respectively), but only improvement of BCVA correlated with the frequency (r2 = 0.15, p = 0.037) and total number of saccades (r2 = 0.18, p = 0.02). BCVA showed no correlation with the amplitude and most frequently occurring saccade amplitude. CONCLUSION Fixational eye movements may be used to monitor short-term effects of anti-VEGF treatment on diabetic macular oedema. Future studies should aim at investigating a possible predictive value of fixational eye movements for visual function in the long term.
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Affiliation(s)
| | | | - Toke Bek
- Department of Ophthalmology; Aarhus University Hospital; Aarhus Denmark
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73
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Bek T, Stefánsson E, Hardarson SH. Retinal oxygen saturation is an independent risk factor for the severity of diabetic retinopathy. Br J Ophthalmol 2018; 103:1167-1172. [PMID: 30337331 DOI: 10.1136/bjophthalmol-2018-312764] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 09/11/2018] [Accepted: 09/17/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND The oxygen saturation in larger retinal vessels has been shown to increase with increasing diabetic retinopathy (DR) grade and to help predict the effect of antivascular endothelial growth factor treatment in patients with diabetic maculopathy. However, it is unknown to what extent the increased oxygen saturation co-varies with other risk factors and whether it is an independent risk factor for the severity of DR. METHODS Seven hundred and twenty-two successive patients referred for specialist evaluation of diabetic retinopathy including retinal oximetry were studied. Multiple regression analysis was used to investigate whether oxygen saturation in the larger retinal arterioles and venules contributed to the severity of diabetic retinopathy, independently of gender, age, diabetes duration, diabetes type, body mass index, blood pressure, haemoglobin A1c, visual acuity and central retinal thickness. RESULTS The included parameters could explain less than 15% of the variation in retinopathy grade. Approximately, one-third of the explained variation was related to the retinal oxygen saturation. CONCLUSIONS Prospective studies are needed to evaluate whether retinal oxygen saturation is predictive for the development of diabetic retinopathy and how it interacts with other biomarkers and risk factors over time.
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Affiliation(s)
- Toke Bek
- Departments of Ophthalmology, University of Iceland, Reykjavik, Iceland
| | - Einar Stefánsson
- Departments of Physiology, University of Iceland, Reykjavik, Iceland.,Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Sveinn Hákon Hardarson
- Departments of Physiology, University of Iceland, Reykjavik, Iceland.,Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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74
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Jeppesen SK, Bek T. The Retinal Oxygen Saturation Measured by Dual Wavelength Oximetry in Larger Retinal Vessels is Influenced by the Linear Velocity of the Blood. Curr Eye Res 2018; 44:46-52. [DOI: 10.1080/02713683.2018.1524015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark
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75
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Dale GH, Petersen T, Bacher Svendsen K, Christensen T, Houen G, Bek T. Time to steroid treatment in severe acute optic neuritis. Brain Behav 2018; 8:e01032. [PMID: 29931830 PMCID: PMC6085902 DOI: 10.1002/brb3.1032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 05/26/2018] [Accepted: 05/29/2018] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES Steroid treatment can accelerate visual recovery in patients with optic neuritis (ON), but it is unknown whether the timing of the start of treatment influences the outcome. The main purpose of this observational study was to assess the effect of early onset steroid treatment of ON on visual prognosis and retinal morphology. METHODS Forty-nine patients with acute mild/moderate (n = 21) or severe (n = 28) ON, and an equal number of healthy controls were enrolled. Patients with severe ON either received early onset steroid treatment (initiated within 1 week of presentation with visual loss) (n = 9), late-onset treatment (initiated after 1 week) (n = 13), or no treatment (n = 6). Visual function and retinal morphology was studied after 6 and 12 months. RESULTS All measures of visual function had improved after 6 months (p ≤ 0.03) in the three groups with severe ON. This was not the case for Rayleigh match setting range (SR) in the nontreated group (p = 0.24), or for SR (p = 0.08) and latency to P100 of visual evoked potential (p = 0.08) in the late-onset treated group. After 12 months, further improvement occurred in the nontreated and late-treated groups, but not in the early treated group. Macular retinal nerve fiber layer (mRNFL) and ganglion cell plus inner plexiform layer had decreased significantly (p ≤ 0.001) in all three groups with severe ON after 6 months. After 12 months, only mRNFL had further significantly decreased and only in the late-onset treated group (p = 0.02). CONCLUSION The beneficial effects of early onset steroid treatment of ON is limited to a few months whereas the long-term prognosis is independent of the timing of treatment.
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Affiliation(s)
- Gro Helen Dale
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Thor Petersen
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | | | | | - Gunnar Houen
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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76
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Dale GH, Svendsen KB, Gjelstrup MC, Christensen T, Houen G, Nielsen E, Bek T, Petersen T. Incidence of neuromyelitis optica spectrum disorder in the Central Denmark Region. Acta Neurol Scand 2018; 137:582-588. [PMID: 29359475 DOI: 10.1111/ane.12903] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2018] [Indexed: 01/05/2023]
Abstract
OBJECTIVES Neuromyelitis optica (NMO)/NMO spectrum disorder (NMOSD) may be misdiagnosed as multiple sclerosis. The aim of this study was to (i) to measure AQP4-IgG in patients who fulfilled the clinical and radiological criteria of NMOSD in the Central Denmark Region and (ii) to estimate the incidence of NMOSD in the region, according to both the 2006 Wingerchuk criteria and the 2015 International Panel for NMO Diagnosis criteria. MATERIALS AND METHODS Medical records of all patients diagnosed with a demyelinating disorder in the region from 1 January 2012 to 31 December 2013 were reviewed. Patients were classified as having (i) "NMO" if the 2006 criteria were met, (ii) "NMOSD with AQP4-IgG" or (iii) "NMOSD without/unknown AQP-IgG" if the new 2015 NMOSD criteria were met. Patients with core symptoms were invited to provide a blood sample for AQP4-IgG analysis with an enzyme-linked immunosorbent assay and a cell-based indirect immunofluorescence assay. RESULTS In 191 patients with core symptoms, one met the 2015 NMOSD with AQP4-IgG criteria. Two patients met the 2006 NMO and 2015 NMOSD without/unknown AQP4-IgG criteria. Among 108 patients providing a blood sample, all were seronegative. The estimated incidence of NMO (2006 criteria) and NMOSD (2015 criteria) was 0.08 and 0.12 per 100 000 person-years, respectively. CONCLUSION NMO/NMOSD is a rare disease in the Central Denmark Region, with a considerably lower incidence rate than previously estimated in a neighbouring region.
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Affiliation(s)
- G. H. Dale
- Department of Neurology; Aarhus University Hospital; Aarhus Denmark
- Department of Biomedicine; Aarhus University; Aarhus Denmark
| | - K. B. Svendsen
- Department of Neurology; Aarhus University Hospital; Aarhus Denmark
| | - M. C. Gjelstrup
- Department of Biomedicine; Aarhus University; Aarhus Denmark
| | - T. Christensen
- Department of Biomedicine; Aarhus University; Aarhus Denmark
| | - G. Houen
- Department of Autoimmunology and Biomarkers; Statens Serum Institut; Copenhagen Denmark
| | - E. Nielsen
- Department of Neuroradiology; Aarhus University Hospital; Aarhus Denmark
| | - T. Bek
- Department of Ophthalmology; Aarhus University Hospital; Aarhus Denmark
| | - T. Petersen
- Department of Neurology; Aarhus University Hospital; Aarhus Denmark
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77
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Dale GH, Bacher Svendsen K, Gjelstrup MC, Christensen T, Houen G, Nielsen E, Bek T, Petersen T. Response to "Epidemiology of neuromyelitis optica spectrum disorder''. Acta Neurol Scand 2018; 137:628-629. [PMID: 29732541 DOI: 10.1111/ane.12937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- G H Dale
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - K Bacher Svendsen
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - M C Gjelstrup
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - T Christensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - G Houen
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - E Nielsen
- Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - T Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - T Petersen
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
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78
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Bek T, Klug SE. Age, sex, and type of medication predict the effect of anti-VEGF treatment on central retinal thickness in wet age-related macular degeneration. Clin Ophthalmol 2018; 12:473-479. [PMID: 29563771 PMCID: PMC5848666 DOI: 10.2147/opth.s158760] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Randomized clinical trials studying the effects of VEGF inhibition on wet age-related macular degeneration (wAMD) are designed so that the effects of individually varying risk factors on the treatment response are eliminated. The influence of these risk factors can be studied in large data sets from real-life experience. Patients and methods All 2,255 patients diagnosed with wAMD requiring anti-VEGF treatment in at least one eye over more than 9 years in a defined Danish population with 0.9 million inhabitants were studied. The predictive value of eye laterality, sex, current smoking status, type of anti-VEGF compound, membrane position, membrane type, leakage area, number of injections, number of visits, age, time to follow-up, visual acuity, and central retinal thickness (CRT) at baseline on change in CRT after three monthly injections with anti-VEGF compound followed by treatment pro re nata for up to 12 months was assessed. Results After 12 months, 67 patients had died, 903 had had stable CRT for at least 6 months, and 1,285 patients had not achieved stable CRT. The reduction in CRT was −84.8±118.3 μm, whereas the increase in visual acuity was 2.2±14.7 Early Treatment Diabetic Retinopathy Study letters. The risk factors included contributed to 64% of the variation in CRT reduction. High age and high CRT at baseline predicted high CRT reduction, whereas more injections, treatment with ranibizumab, and male sex predicted a low CRT reduction. Conclusion Age, sex, and type of anti-VEGF medication can be used to plan treatment and inform patients about the expected response of anti-VEGF treatment in wAMD.
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Affiliation(s)
- Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Sidsel Ehlers Klug
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
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79
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Bek T. Is lack of autonomic nerves in retinal vessels a protection from electrical stimulation generated by activity in visual neurons? Acta Ophthalmol 2018; 96:e263. [PMID: 29098795 DOI: 10.1111/aos.13578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Toke Bek
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
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80
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Tranebjærg L, Strenzke N, Lindholm S, Rendtorff ND, Poulsen H, Khandelia H, Kopec W, Lyngbye TJB, Hamel C, Delettre C, Bocquet B, Bille M, Owen HH, Bek T, Jensen H, Østergaard K, Möller C, Luxon L, Carr L, Wilson L, Rajput K, Sirimanna T, Harrop-Griffiths K, Rahman S, Vona B, Doll J, Haaf T, Bartsch O, Rosewich H, Moser T, Bitner-Glindzicz M. Correction to: The CAPOS mutation in ATP1A3 alters Na/K-ATPase function and results in auditory neuropathy which has implications for management. Hum Genet 2018; 137:279-280. [PMID: 29435658 DOI: 10.1007/s00439-018-1870-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The following information was inadvertently omitted in the original publication.
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Affiliation(s)
- Lisbeth Tranebjærg
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet/Bispebjerg, Copenhagen, Denmark. .,Department of Clinical Genetics, The Kennedy Center, Copenhagen University Hospital, Copenhagen, Denmark. .,Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Nicola Strenzke
- Auditory Systems Physiology Group, InnerEarLab, Department of Otolaryngology, University Medical Center, Göttingen, Germany
| | | | - Nanna D Rendtorff
- Department of Clinical Genetics, The Kennedy Center, Copenhagen University Hospital, Copenhagen, Denmark
| | - Hanne Poulsen
- Institute of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Himanshu Khandelia
- MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
| | - Wojciech Kopec
- MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark.,Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | | | - Christian Hamel
- Maladies Sensorielles Genetiques, CHRU, Montpellier, France.,INSERM U1051, Institute for Neurosciences of Montpellier, Montpellier, France.,Universite Montpellier, Montpellier, France
| | - Cecile Delettre
- INSERM U1051, Institute for Neurosciences of Montpellier, Montpellier, France.,Universite Montpellier, Montpellier, France
| | - Beatrice Bocquet
- Maladies Sensorielles Genetiques, CHRU, Montpellier, France.,INSERM U1051, Institute for Neurosciences of Montpellier, Montpellier, France.,Universite Montpellier, Montpellier, France
| | - Michael Bille
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet/Gentofte Hospital, Hellerup, Denmark
| | - Hanne H Owen
- Department of Audiology, Aarhus University Hospital, Aarhus, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Hanne Jensen
- Eye Department Glostrup Hospital, Rigshospitalet, The Kennedy Centre, Glostrup, Denmark
| | - Karen Østergaard
- Department of Neurology, Aarhus University Hospital and University of Aarhus, Aarhus, Denmark
| | - Claes Möller
- Audiological Research Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Linda Luxon
- Department of Neurotology, National Hospital for Neurology, Queen Square, London, WC1N 3BG, UK
| | - Lucinda Carr
- Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK
| | - Louise Wilson
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK
| | - Kaukab Rajput
- Cochlear Implant Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK
| | - Tony Sirimanna
- Department of Audiovestibular Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK
| | | | - Shamima Rahman
- Genetic and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, WC1N 1EH, UK
| | - Barbara Vona
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Julia Doll
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Oliver Bartsch
- University Medical Centre, Institute of Human Genetics, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, Mainz, Germany
| | - Hendrik Rosewich
- Division of Pediatric Neurology, Department of Pediatric and Adolescent Medicine, University Medical Center, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center, Göttingen, Germany
| | - Maria Bitner-Glindzicz
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK. .,Genetic and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, London, WC1N 1EH, UK.
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81
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Askou AL, Alsing S, Holmgaard A, Bek T, Corydon TJ. Dissecting microRNA dysregulation in age-related macular degeneration: new targets for eye gene therapy. Acta Ophthalmol 2018; 96:9-23. [PMID: 28271607 DOI: 10.1111/aos.13407] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/02/2017] [Indexed: 02/06/2023]
Abstract
MicroRNAs (miRNAs) are key regulators of gene expression in humans. Overexpression or depletion of individual miRNAs is associated with human disease. Current knowledge suggests that the retina is influenced by miRNAs and that dysregulation of miRNAs as well as alterations in components of the miRNA biogenesis machinery are involved in retinal diseases, including age-related macular degeneration (AMD). Furthermore, recent studies have indicated that the vitreous has a specific panel of circulating miRNAs and that this panel varies according to the specific pathological stress experienced by the retinal cells. MicroRNA (miRNA) profiling indicates subtype-specific miRNA profiles for late-stage AMD highlighting the importance of proper miRNA regulation in AMD. This review will describe the function of important miRNAs involved in inflammation, oxidative stress and pathological neovascularization, the key molecular mechanisms leading to AMD, and focus on dysregulated miRNAs as potential therapeutic targets in AMD.
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Affiliation(s)
| | - Sidsel Alsing
- Department of Biomedicine; Aarhus University; Aarhus C Denmark
| | | | - Toke Bek
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
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82
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Wong D, Chan YK, Bek T, Wilson I, Stefánsson E. Intraocular currents, Bernoulli's principle and non-drainage scleral buckling for rhegmatogenous retinal detachment. Eye (Lond) 2018; 32:213-221. [PMID: 29350687 DOI: 10.1038/eye.2017.312] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 11/30/2017] [Indexed: 11/09/2022] Open
Abstract
For many years, it is not fully understood how non-drainage scleral buckling surgery brings about spontaneous reattachment of the detached retina when retinal breaks remain open at the end of surgery. Various explanations have been put forward, but none more interesting than the effect of fluid currents associated with eye movements. One such explanation involved the physics of the Bernoulli's principle. Daniel Bernoulli was an eighteenth century Swiss mathematician and he described an equation based on the conservation of energy. The sum of pressure energy, potential energy and kinetic energy remains constant. Bernoulli's equation usually applies to closed system such as the flow of fluid through pipes. When fluid flows through a constriction, the speed of fluid increases, the kinetic energy increases. If there was no change in elevation (potential energy), then the increase in kinetic energy must be accompanied by a decrease in pressure energy. In ophthalmic surgery, the Bernoulli's effect is the basis for venturi pumps that drive vitrectomy and phacoemulsification machines. This essay expounds on how Bernoulli's effect might be relevant to scleral buckling for retinal detachment repair. In the era when vitrectomy is increasing the primary surgical operation for retinal detachment, the pervasive advice is to emphasise the importance of patient adopting head posture and remaining still postoperatively. The exception is non-drainage scleral buckling surgery. Early postoperative mobilisation may be vital to achieve reattachment.
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Affiliation(s)
- D Wong
- Royal Liverpool University Hospital, Liverpool, UK
| | - Y K Chan
- Department of Mechanical Engineering, University of Hong Kong, Hong Kong SAR, China
| | - T Bek
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - I Wilson
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - E Stefánsson
- Landspitali University hospital, University of Iceland, Reykjavík, Iceland
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83
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Stefánsson E, Chan YK, Bek T, Hardarson SH, Wong D, Wilson DI. Laws of physics help explain capillary non-perfusion in diabetic retinopathy. Eye (Lond) 2018; 32:210-212. [PMID: 29350688 DOI: 10.1038/eye.2017.313] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/03/2017] [Indexed: 01/09/2023] Open
Abstract
The purpose is to use laws of physics to elucidate the mechanisms behind capillary non-perfusion in diabetic retinopathy. In diabetic retinopathy, loss of pericytes weakens capillary walls and the vessel dilates. A dilated capillary has reduced resistance to flow, therefore increased flow in that vessel and decreased in adjoining capillaries. A preferential shunt vessel is thus formed from the dilated capillary and the adjacent capillaries become non-perfused. We apply the laws of Laplace and Hagen-Poiseuille to better understand the phenomena that lead to capillary non-perfusion. These laws of physics can give a foundation for physical or mathematical models to further elucidate this field of study. The law of Laplace predicts that a weaker vessel wall will dilate, assuming constant transmural pressure. The Hagen-Poiseuille equation for flow and the Ostwald-de Waele relationship for viscosity predict that a dilated vessel will receive a higher portion of the fluid flow than the adjoining capillaries. Viscosity will decrease in the dilated vessel, furthering the imbalance and resulting in a patch of non-perfused capillaries next to the dilated 'preferential' shunt vessel. Physical principles support or inspire novel hypotheses to explain poorly understood phenomena in ophthalmology. This thesis of pericyte death and capillary remodelling, which was first proposed by Cogan and Kuwabara, already agrees with histological and angiographical observations in diabetic retinopathy. We have shown that it is also supported by classical laws of physics.
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Affiliation(s)
- E Stefánsson
- Landspitali University Hospital, University of Iceland, Reykjavík, Iceland
| | - Y K Chan
- Department of Mechanical Engineering, University of Hong Kong, Hong Kong SAR, China
| | - T Bek
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - S H Hardarson
- Institue of Physiology, University of Iceland, Reykjavik, Iceland
| | - D Wong
- Royal Liverpool University Hospital, Liverpool, UK
| | - D I Wilson
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
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84
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Bek T, Kjaergaard J. The Prognostic Value of Post-Treatment Retinopathy after Panretinal Photocoagulation for Proliferative Diabetic Retinopathy in Type 1 Diabetes. Eur J Ophthalmol 2018; 14:538-42. [PMID: 15638104 DOI: 10.1177/112067210401400614] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To study the prognostic value of post-treatment retinopathy after panretinal laser photocoagulation for proliferative diabetic retinopathy in type 1 diabetes mellitus. Proliferative diabetic retinopathy is treated with panretinal photocoagulation, which significantly reduces the risk of visual loss from this complication. However, no parameters are presently known that can be used to define an optimal control interval after the initial panretinal photocoagulation treatment that ensures enhancement of the treatment in cases where this is needed. METHODS In this retrospective cohort study, 85 eyes from 56 type 1 diabetic patients were identified who had been subjected to panretinal photocoagulation for proliferative diabetic retinopathy before 1990. The patients were divided into two groups: Group 1 had four or fewer microaneurysms only at the first post-treatment examination whereas Group 2 had more retinopathy. RESULTS At the first photographic examination after treatment the eyes in Group 1 had a significantly lower visual acuity (VA) (mean =0.23, range: 0.01-1.00) than the patients in Group 2 (mean=0.48, range: 0.01-1.6). During the follow-up period the VA was further reduced in Group 2 but not in Group 1. Three eyes out of six in Group 1 had improvement of VA from below to above 0.1, whereas 6 eyes out of 12 in Group 2 experienced progression of retinopathy with a consequent worsening of VA to below 0.1 after a mean of 10.8 years (range: 6.8-15.9) after treatment. CONCLUSIONS The severity of post-treatment retinopathy can be used to assess the need for enhancing photocoagulation of proliferative diabetic retinopathy in type 1 diabetes. The interval between post-treatment examinations can be increased to several years when the initial treatment has reduced retinopathy to a minimal level.
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Affiliation(s)
- T Bek
- Department of Ophthalmology, Arhus University Hospital, Arhus- Denmark.
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85
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Askou AL, Benckendorff JNE, Holmgaard A, Storm T, Aagaard L, Bek T, Mikkelsen JG, Corydon TJ. Suppression of Choroidal Neovascularization in Mice by Subretinal Delivery of Multigenic Lentiviral Vectors Encoding Anti-Angiogenic MicroRNAs. Hum Gene Ther Methods 2018; 28:222-233. [PMID: 28817343 DOI: 10.1089/hgtb.2017.079] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Lentivirus-based vectors have been used for the development of potent gene therapies. Here, application of a multigenic lentiviral vector (LV) producing multiple anti-angiogenic microRNAs following subretinal delivery in a laser-induced choroidal neovascularization (CNV) mouse model is presented. This versatile LV, carrying back-to-back RNApolII-driven expression cassettes, enables combined expression of microRNAs targeting vascular endothelial growth factor A (Vegfa) mRNA and fluorescent reporters. In addition, by including a vitelliform macular dystrophy 2 (VMD2) promoter, expression of microRNAs is restricted to the retinal pigment epithelial (RPE) cells. Six days post injection (PI), robust and widespread fluorescent signals of eGFP are already observed in the retina by funduscopy. The eGFP expression peaks at day 21 PI and persists with stable expression for at least 9 months. In parallel, prominent AsRED co-expression, encoded from the VMD2-driven microRNA expression cassette, is evident in retinal sections and flat-mounts, revealing RPE-specific expression of microRNAs. Furthermore, LV-delivered microRNAs targeting the Vegfa gene in RPE cells reduced the size of laser-induced CNV in mice 28 days PI, as a consequence of diminished VEGF levels, suggesting that LVs delivered locally are powerful tools in the development of gene therapy-based strategies for treatment of age-related macular degeneration.
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Affiliation(s)
| | | | | | - Tina Storm
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Lars Aagaard
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Toke Bek
- 2 Department of Ophthalmology, Aarhus University Hospital , Aarhus, Denmark
| | | | - Thomas Juhl Corydon
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark .,2 Department of Ophthalmology, Aarhus University Hospital , Aarhus, Denmark
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86
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Ometto G, Assheton P, Calivá F, Chudzik P, Al-Diri B, Hunter A, Bek T. Spatial distribution of early red lesions is a risk factor for development of vision-threatening diabetic retinopathy. Diabetologia 2017; 60:2361-2367. [PMID: 28884200 PMCID: PMC6449026 DOI: 10.1007/s00125-017-4424-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 07/18/2017] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Diabetic retinopathy is characterised by morphological lesions related to disturbances in retinal blood flow. It has previously been shown that the early development of retinal lesions temporal to the fovea may predict the development of treatment-requiring diabetic maculopathy. The aim of this study was to map accurately the area where lesions could predict progression to vision-threatening retinopathy. METHODS The predictive value of the location of the earliest red lesions representing haemorrhages and/or microaneurysms was studied by comparing their occurrence in a group of individuals later developing vision-threatening diabetic retinopathy with that in a group matched with respect to diabetes type, age, sex and age of onset of diabetes mellitus who did not develop vision-threatening diabetic retinopathy during a similar observation period. RESULTS The probability of progression to vision-threatening diabetic retinopathy was higher in a circular area temporal to the fovea, and the occurrence of the first lesions in this area was predictive of the development of vision-threatening diabetic retinopathy. The calculated peak value showed that the risk of progression was 39.5% higher than the average. There was no significant difference in the early distribution of lesions in participants later developing diabetic maculopathy or proliferative diabetic retinopathy. CONCLUSIONS/INTERPRETATION The location of early red lesions in diabetic retinopathy is predictive of whether or not individuals will later develop vision-threatening diabetic retinopathy. This evidence should be incorporated into risk models used to recommend control intervals in screening programmes for diabetic retinopathy.
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Affiliation(s)
- Giovanni Ometto
- Department of Ophthalmology, Aarhus University Hospital, DK-8000, Aarhus C, Denmark.
| | - Phil Assheton
- Maths and Stats Help Centre, University of Lincoln, Lincoln, UK
| | - Francesco Calivá
- School of Computer Science, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Piotr Chudzik
- School of Computer Science, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Bashir Al-Diri
- School of Computer Science, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Andrew Hunter
- School of Computer Science, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK.
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, DK-8000, Aarhus C, Denmark
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87
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El Dabagh Y, Petersen L, Pedersen M, Bek T. The Diameter of Retinal Vessels Is Affected by Transient Ischemia of the Arm in Normal Persons. Invest Ophthalmol Vis Sci 2017; 58:5263-5269. [PMID: 29049727 DOI: 10.1167/iovs.17-22461] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Remote ischemic conditioning (RIC) implies that transient ischemia in a limb can affect perfusion in a target organ elsewhere in the body. The changes in perfusion can be assumed to be paralleled by changes in the vessel diameters in the target organ. It remains to be elucidated whether the diameter of normal retinal vessels can be used as a marker of RIC in vivo. Methods In 20 normal persons aged 20 to 31 years the Dynamic Vessel Analyzer (DVA) was used to measure the resting diameter and diameter changes during isometric exercise and flicker stimulation before, immediately after, and 1 hour after RIC induced by transient ischemia in the left arm. Results The baseline diameter of retinal venules was reduced nonsignificantly immediately after (P = 0.07) and significantly 1 hour after RIC (P = 0.009), whereas the baseline diameter of arterioles was unaffected by the intervention (P = 0.61). Arterial constriction induced by isometric exercise was significantly reduced immediately after RIC (P = 0.04), but not 1 hour after RIC (P = 0.99). None of the other diameter responses were affected by RIC (P = 0.22 for all comparisons). Conclusions The diameter of retinal vessels might potentially be a marker of ischemic conditioning in the body in general. The effect of RIC on retinal vascular diseases where ischemia is a part of the pathogenesis should be investigated.
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Affiliation(s)
- Yasmin El Dabagh
- Department of Ophthalmology, Aarhus University Hospital, Denmark.,Comparative Medicine Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Denmark
| | - Line Petersen
- Department of Ophthalmology, Aarhus University Hospital, Denmark
| | - Michael Pedersen
- Comparative Medicine Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Denmark
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88
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Holmgaard A, Askou AL, Benckendorff JNE, Thomsen EA, Cai Y, Bek T, Mikkelsen JG, Corydon TJ. In Vivo Knockout of the Vegfa Gene by Lentiviral Delivery of CRISPR/Cas9 in Mouse Retinal Pigment Epithelium Cells. Mol Ther Nucleic Acids 2017; 9:89-99. [PMID: 29246327 PMCID: PMC5626917 DOI: 10.1016/j.omtn.2017.08.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/29/2017] [Accepted: 08/29/2017] [Indexed: 12/26/2022]
Abstract
Virus-based gene therapy by CRISPR/Cas9-mediated genome editing and knockout may provide a new option for treatment of inherited and acquired ocular diseases of the retina. In support of this notion, we show that Streptococcus pyogenes (Sp) Cas9, delivered by lentiviral vectors (LVs), can be used in vivo to selectively ablate the vascular endothelial growth factor A (Vegfa) gene in mice. By generating LVs encoding SpCas9 targeted to Vegfa, and in parallel the fluorescent eGFP marker protein, we demonstrate robust knockout of Vegfa that leads to a significant reduction of VEGFA protein in transduced cells. Three of the designed single-guide RNAs (sgRNAs) induce in vitro indel formation at high frequencies (44%-93%). A single unilateral subretinal injection facilitates RPE-specific localization of the vector and disruption of Vegfa in isolated eGFP+ RPE cells obtained from mice five weeks after LV administration. Notably, sgRNA delivery results in the disruption of Vegfa with an in vivo indel formation efficacy of up to 84%. Sequencing of Vegfa-specific amplicons reveals formation of indels, including 4-bp deletions and 2-bp insertions. Taken together, our data demonstrate the capacity of lentivirus-delivered SpCas9 and sgRNAs as a developing therapeutic path in the treatment of ocular diseases, including age-related macular degeneration.
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Affiliation(s)
- Andreas Holmgaard
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Anne Louise Askou
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | | | - Yujia Cai
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark
| | | | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Ophthalmology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
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89
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Kratholm NM, Jensen PS, Kringelholt S, Simonsen U, Bek T. Activation of Veratridine Sensitive Sodium Channels, But not Electrical Field Stimulation, Dilates Porcine Retinal Arterioles with Preserved Perivascular Tissue. Curr Eye Res 2017; 42:1497-1502. [PMID: 28910154 DOI: 10.1080/02713683.2017.1337156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Disturbances in retinal blood flow are a prominent feature of vision threatening retinal diseases. The regulation of tone in retinal resistance vessels involves the perivascular retinal tissue, but it is unknown to what extent neurons or glial cells contribute to the effect. Therefore, the purpose of the present study was to study the contribution of neurons in the perivascular retina to vascular tone during activation of voltage-gated sodium channels with veratridine and electrical field stimulation (EFS). METHODS Porcine retinal arterioles with and without perivascular tissue were mounted in an isometric myograph system for studying the effects of the voltage-gated sodium channel opener veratridine and EFS on retinal vascular tone. RESULTS Veratridine induced concentration-dependent relaxation of retinal arterioles which was more pronounced in arterioles with preserved perivascular retinal tissue than in isolated vessels. In the presence of this tissue, veratridine-induced relaxation was inhibited by the voltage-gated sodium channel blocker tetrodotoxin and the nitric oxide synthase inhibitor, Nω-Nitro-L-arginine methyl ester (L-NAME), but was unaffected by the inhibition of the cyclo-oxygenase inbitior ibuprofen and by blocking of adenosine receptors with 8-(p-Sulfophenyl)theophylline hydrate (8-PSPT). Electrical field stimulation induced no changes in retinal vascular tone. CONCLUSIONS Sodium channels of neuronal origin are likely to be involved in the regulation of retinal vascular tone. The lack of effect of EFS on retinal vascular tone may be due to the lack of autonomic nerves in the retina.
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Affiliation(s)
- Nils M Kratholm
- a Department of Ophthalmology , Aarhus University Hospital , Aarhus C , Denmark
| | - Peter Skov Jensen
- a Department of Ophthalmology , Aarhus University Hospital , Aarhus C , Denmark
| | - Sidse Kringelholt
- a Department of Ophthalmology , Aarhus University Hospital , Aarhus C , Denmark
| | - Ulf Simonsen
- b Department of Biomedicine (Pharmacology) , University of Aarhus , Aarhus C , Denmark
| | - Toke Bek
- a Department of Ophthalmology , Aarhus University Hospital , Aarhus C , Denmark
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90
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Kudryavtseva O, Aalkjaer C, Bek T. Microelectrode penetration of the wall of porcine retinal arterioles in vitro results in recordings from several cell types. Acta Ophthalmol 2017. [DOI: 10.1111/j.1755-3768.2017.0f069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - C. Aalkjaer
- Biomedicine; Aarhus University; Aarhus Denmark
| | - T. Bek
- Ophthalmology; Aarhus University Hospital; Aarhus Denmark
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91
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Jeppesen S, Bek T. Retinal oximetry in central retinal vein occlusion. Acta Ophthalmol 2017. [DOI: 10.1111/j.1755-3768.2017.01142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- S.K. Jeppesen
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
| | - T. Bek
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
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92
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Bek T. Measurement of retinal blood flow using Doppler OCT in diabetic retinopathy. Acta Ophthalmol 2017. [DOI: 10.1111/j.1755-3768.2017.01141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- T. Bek
- Ophthalmology; Arhus University Hospital; Århus C Denmark
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93
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El Dabagh Y, Petersen L, Pedersen M, Bek T. Remote ischemia affects the diameter of larger retinal vessels in normal persons. Acta Ophthalmol 2017. [DOI: 10.1111/j.1755-3768.2017.01378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Y. El Dabagh
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
| | - L. Petersen
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
| | - M. Pedersen
- Department of Clinical Medicine; Aarhus University Hospital; Aarhus C Denmark
| | - T. Bek
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
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94
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Stefánsson E, Olafsdottir OB, Einarsdottir AB, Eliasdottir TS, Eysteinsson T, Vehmeijer W, Vandewalle E, Bek T, Hardarson SH. Retinal Oximetry Discovers Novel Biomarkers in Retinal and Brain Diseases. ACTA ACUST UNITED AC 2017; 58:BIO227-BIO233. [DOI: 10.1167/iovs.17-21776] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Einar Stefánsson
- University of Iceland, Reykjavik, Iceland 2Landspitali University Hospital, Reykjavik, Iceland
| | - Olof Birna Olafsdottir
- University of Iceland, Reykjavik, Iceland 2Landspitali University Hospital, Reykjavik, Iceland
| | | | | | | | | | - Evelien Vandewalle
- Universitaire ziekenhuizen Leuven–University Hospital of Leuven, Leuven, Belgium 6Katholieke Universiteit Leuven–University of Leuven, Leuven, Belgium
| | - Toke Bek
- Aarhus University Hospital, Aarhus, Denmark
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95
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Abstract
PURPOSE OF REVIEW The diameter of retinal vessels is an important source of information about retinal blood flow and metabolism. The purpose of the present study is to review how diameter changes of retinal vessels contribute to the development of diabetic retinopathy and may be a marker of the prognosis of the disease. RECENT FINDINGS The early stages of diabetic retinopathy are accompanied with dilatation of the diameter of retinal vessels and reduced autoregulation. Diabetic retinopathy also shows regional differences in the macular area and the retinal periphery and accompanying differences in vascular reactivity in these areas. These differences may potentially become an important source of insight into the pathophysiology of the disease in the future. Diabetic retinopathy is accompanied with changes in the diameter regulation of retinal vessels. The potential of newly developed techniques for assessing retinal blood flow and metabolism, such as Doppler techniques, adaptive optics, and retinal oximetry, is promising and may potentially contribute to significant advances in our understanding of diabetic retinopathy which remains a major cause of visual impairment.
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Affiliation(s)
- Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, 8000, Aarhus C, Denmark.
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96
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Just J, Lykkemark S, Nielsen CH, Roshenas AR, Drasbek KR, Petersen SV, Bek T, Kristensen P. Pericyte modulation by a functional antibody obtained by a novel single-cell selection strategy. Microcirculation 2017; 24. [DOI: 10.1111/micc.12365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/21/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Jesper Just
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus C Denmark
- Department of Clinical Medicine; Aarhus University; Aarhus C Denmark
| | - Simon Lykkemark
- Department of Clinical Medicine; Aarhus University; Aarhus C Denmark
- Sino-Danish Centre for Education and Research (SDC); Aarhus C Denmark
| | - Charlotte H. Nielsen
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus C Denmark
| | - Ali R. Roshenas
- Department of Engineering; Aarhus University; Aarhus C Denmark
| | - Kim R. Drasbek
- Department of Clinical Medicine; Aarhus University; Aarhus C Denmark
| | | | - Toke Bek
- Department of Clinical Medicine; Aarhus University; Aarhus C Denmark
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97
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Askou AL, Benckendorff JNE, Holmgaard A, Storm T, Aagaard L, Bek T, Mikkelsen JG, Corydon TJ. Suppression of choroidal neovascularization in mice by subretinal delivery of multigenic lentiviral vectors encoding anti-angiogenic microRNAs. Hum Gene Ther Methods 2017. [DOI: 10.1089/hum.2017.079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Affiliation(s)
| | | | | | - Tina Storm
- Aarhus University, Department of Biomedicine, Aarhus C, Denmark
| | - Lars Aagaard
- Aarhus University, Department of Biomedicine, Aarhus C, Denmark
| | - Toke Bek
- Aarhus University Hospital, Department of Ophthalmology, Aarhus C, Denmark
| | | | - Thomas Juhl Corydon
- Aarhus University, Department of Biomedicine, Wilhelm Meyers Alle, Aarhus C, Denmark, 8000
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98
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Petersen L, Bek T. Post-hypoxic constriction of retinal arterioles is impaired during nitric oxide and cyclo-oxygenase inhibition and in diabetic patients without retinopathy. Graefes Arch Clin Exp Ophthalmol 2017; 255:1965-1971. [DOI: 10.1007/s00417-017-3746-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/23/2017] [Accepted: 07/05/2017] [Indexed: 01/14/2023] Open
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99
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Jakobsen NS, Larsen DA, Bek T. Binocular Fixation Reduces Fixational Eye Movements in the Worst Eye of Patients with Center-Involving Diabetic Macular Edema. Ophthalmic Res 2017; 58:142-149. [PMID: 28683455 DOI: 10.1159/000476038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/25/2017] [Indexed: 11/19/2022]
Abstract
PURPOSE Treatment of diabetic maculopathy with vascular endothelial growth factor inhibitors is in some patients ineffective, and, therefore, parameters predicting visual outcome after treatment should be identified. It has been shown that fixational saccades are increased in patients with reduced visual acuity secondary to diabetic maculopathy, but it is unknown to what extent these saccades in an eye affected by diabetic maculopathy are influenced by the other eye during binocular fixation. METHODS In 57 eyes from 29 diabetic patients with clinically significant macular edema, fixational eye movements were recorded using the iView X™ video-based eye tracker, and quantitative measures of fixation with the worst eye obtained during monocular and binocular fixation were compared. RESULTS Fixational saccades during monocular fixation had a significantly higher frequency (p = 0.005), a larger amplitude (p = 0.03), and involved a larger retinal area (p = 0.02) than during binocular fixation. There was a significant negative correlation (r2 = 0.18, p = 0.02) between visual acuity and the area of fixation during monocular but not during binocular fixation (r2 = 0.007, p = 0.68). CONCLUSION Binocular fixation can reduce the area of fixation and the amplitude of fixational saccades in the worst eye of patients with diabetic maculopathy. Fixational saccades in diabetic maculopathy should be studied during monocular fixation.
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100
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Ometto G, Erlandsen M, Hunter A, Bek T. The role of retinopathy distribution and other lesion types for the definition of examination intervals during screening for diabetic retinopathy. Acta Ophthalmol 2017; 95:400-404. [PMID: 27864877 DOI: 10.1111/aos.13334] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 10/10/2016] [Indexed: 01/19/2023]
Abstract
PURPOSE It has previously been shown that the intervals between screening examinations for diabetic retinopathy can be optimized by including individual risk factors for the development of the disease in the risk assessment. However, in some cases, the risk model calculating the screening interval may recommend a different interval than an experienced clinician. The purpose of this study was to evaluate the influence of factors unrelated to diabetic retinopathy and the distribution of lesions for discrepancies between decisions made by the clinician and the risk model. METHODS Therefore, fundus photographs from 90 screening examinations where the recommendations of the clinician and a risk model had been discrepant were evaluated. Forty features were defined to describe the type and location of the lesions, and classification and ranking techniques were used to assess whether the features could predict the discrepancy between the grader and the risk model. RESULTS Suspicion of tumours, retinal degeneration and vascular diseases other than diabetic retinopathy could explain why the clinician recommended shorter examination intervals than the model. Additionally, the regional distribution of microaneurysms/dot haemorrhages was important for defining a photograph as belonging to the group where both the clinician and the risk model had recommended a short screening interval as opposed to the other decision alternatives. CONCLUSIONS Features unrelated to diabetic retinopathy and the regional distribution of retinal lesions may affect the recommendation of the examination interval during screening for diabetic retinopathy. The development of automated computerized algorithms for extracting information about the type and location of retinal lesions could be expected to further optimize examination intervals during screening for diabetic retinopathy.
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Affiliation(s)
- Giovanni Ometto
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
| | - Mogens Erlandsen
- Section for Biostatistics; Department of Public Health; University of Aarhus; Aarhus C Denmark
| | - Andrew Hunter
- School of Computer Science; University of Lincoln; Lincoln UK
| | - Toke Bek
- Department of Ophthalmology; Aarhus University Hospital; Aarhus C Denmark
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