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Lykke L, Ernst C, Bek T. The vasoactive effects of bradykinin, vasoactive intestinal peptide, calcitonin gene-related peptide and neuropeptide Y depend on the perivascular tissue in porcine retinal arterioles in vitro. Acta Ophthalmol 2024; 102:349-356. [PMID: 37565361 DOI: 10.1111/aos.15742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 06/27/2023] [Accepted: 07/27/2023] [Indexed: 08/12/2023]
Abstract
PURPOSE The retina contains a number of vasoactive neuropeptides and corresponding receptors, but the role of these neuropeptides for tone regulation of retinal arterioles has not been studied in detail. METHODS Porcine arterioles with preserved perivascular retinal tissue were mounted in a wire myograph, and the tone was measured after the addition of increasing concentrations of bradykinin, vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), substance P (SP), calcitonin gene-related peptide (CGRP) and brain natriuretic peptide (BNP). The experiments were performed during inhibition of the synthesis of nitric oxide (NO), prostaglandins and dopamine and were repeated after removal of the perivascular retinal tissue. RESULTS Bradykinin, VIP and CGRP induced significant concentration-dependent dilatation and NPY significant concentration-dependent contraction of the arterioles in the presence of perivascular retinal tissue (p < 0.03 for all comparisons) but not on isolated arterioles. BNP and SP had no effect on vascular tone. The NOS inhibitor L-NAME reduced bradykinin- and VIP-induced relaxation (p < 0.001 for both comparisons), whereas none of the other inhibitors influenced the vasoactive effects of the studied neuropeptides. CONCLUSION The effects of neuropeptides on the tone of retinal arterioles depend on the perivascular retinal tissue and may involve effects other than those mediated by nitric oxide, prostaglandins and adrenergic compounds. Investigation of the mechanisms underlying the vasoactive effect of neuropeptides may be important for understanding and treating retinal diseases where disturbances in retinal flow regulation are involved in the disease pathogenesis.
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Affiliation(s)
- Lise Lykke
- Department of Ophthalmology, Aarhus University Hospital, Aarhus N, Denmark
| | - Charlotte Ernst
- Department of Ophthalmology, Aarhus University Hospital, Aarhus N, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, Aarhus N, Denmark
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2
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Hommer N, Kallab M, Schlatter A, Howorka K, Werkmeister RM, Schmidl D, Schmetterer L, Garhöfer G. Retinal Oxygen Metabolism in Patients With Type 2 Diabetes and Different Stages of Diabetic Retinopathy. Diabetes 2022; 71:2677-2684. [PMID: 36107468 PMCID: PMC9862478 DOI: 10.2337/db22-0219] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 09/11/2022] [Indexed: 02/05/2023]
Abstract
The aim of this cross-sectional study was to assess retinal oxygen metabolism in patients with type 2 diabetes and different stages of nonproliferative diabetic retinopathy (DR) (n = 67) compared with healthy control subjects (n = 20). Thirty-four patients had no DR, 15 had mild DR, and 18 had moderate to severe DR. Retinal oxygen saturation in arteries and veins was measured using the oxygen module of a retinal vessel analyzer. Total retinal blood flow (TRBF) was measured using a custom-built Doppler optical coherence tomography system. Retinal oxygen extraction was calculated from retinal oxygen saturation and TRBF. Arteriovenous difference in oxygen saturation was highest in healthy subjects (34.9 ± 7.5%), followed by patients with no DR (32.5 ± 6.3%) and moderate to severe DR (30.3 ± 6.5%). The lowest values were found in patients with mild DR (27.3 ± 8.0%, P = 0.010 vs. healthy subjects). TRBF tended to be higher in patients with no DR (40.1 ± 9.2 μL/min) and mild DR (41.8 ± 15.0 μL/min) than in healthy subjects (37.2 ± 5.7 μL/min) and patients with moderate to severe DR (34.6 ± 10.4 μL/min). Retinal oxygen extraction was the highest in healthy subjects (2.24 ± 0.57 μL O2/min), followed by patients with no DR (2.14 ± 0.6 μL O2/min), mild DR (1.90 ± 0.77 μL O2/min), and moderate to severe DR (1.78 ± 0.57 μL O2/min, P = 0.040 vs. healthy subjects). These results indicate that retinal oxygen metabolism is altered in patients with type 2 diabetes. Furthermore, retinal oxygen extraction decreases with increasing severity of DR.
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Affiliation(s)
- Nikolaus Hommer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Martin Kallab
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Andreas Schlatter
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Vienna Institute for Research in Ocular Surgery, Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria
| | - Kinga Howorka
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - René M. Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
- Singapore Eye Research Institute-Nanyang Technical University Advanced Ocular Engineering (STANCE), Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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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] [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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4
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Gerhard G, Chua J, Tan B, Wong D, Schmidl D, Schmetterer L. Retinal Neurovascular Coupling in Diabetes. J Clin Med 2020; 9:jcm9092829. [PMID: 32882896 PMCID: PMC7565465 DOI: 10.3390/jcm9092829] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/23/2020] [Accepted: 08/27/2020] [Indexed: 12/15/2022] Open
Abstract
Neurovascular coupling, also termed functional hyperemia, is one of the physiological key mechanisms to adjust blood flow in a neural tissue in response to functional activity. In the retina, increased neural activity, such as that induced by visual stimulation, leads to the dilatation of retinal arterioles, which is accompanied by an immediate increase in retinal and optic nerve head blood flow. According to the current scientific view, functional hyperemia ensures the adequate supply of nutrients and metabolites in response to the increased metabolic demand of the neural tissue. Although the molecular mechanisms behind neurovascular coupling are not yet fully elucidated, there is compelling evidence that this regulation is impaired in a wide variety of neurodegenerative and vascular diseases. In particular, it has been shown that the breakdown of the functional hyperemic response is an early event in patients with diabetes. There is compelling evidence that alterations in neurovascular coupling precede visible signs of diabetic retinopathy. Based on these observations, it has been hypothesized that a breakdown of functional hyperemia may contribute to the retinal complications of diabetes such as diabetic retinopathy or macular edema. The present review summarizes the current evidence of impaired neurovascular coupling in patients with diabetes. In this context, the molecular mechanisms of functional hyperemia in health and disease will be covered. Finally, we will also discuss how neurovascular coupling may in future be used to monitor disease progression or risk stratification.
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Affiliation(s)
- Garhöfer Gerhard
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (G.G.); (D.S.)
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
| | - Bingyao Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
| | - Damon Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (G.G.); (D.S.)
| | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (G.G.); (D.S.)
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
- Institute for Health Technologies, Nanyang Technological University, Singapore 308232, Singapore
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, 1090 Vienna, Austria
- Institute of Molecular and Clinical Ophthalmology, CH-4031 Basel, Switzerland
- Correspondence: ; Tel.: +43-1-40400-29810
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/15/2019] [Indexed: 11/19/2022]
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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] [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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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: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [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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8
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Bek T. Translational research in retinal vascular disease. An approach. Acta Ophthalmol 2019; 97:441-450. [PMID: 30801973 DOI: 10.1111/aos.14045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/12/2019] [Indexed: 12/24/2022]
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] [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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10
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Abstract
Our goal was to examine whether in utero exposure to alcohol impaired reactivity of cerebral arterioles during development. We fed Sprague-Dawley dams a liquid diet with or without alcohol (3% ethanol) for the duration of pregnancy (21-23 days). Around 4-6 weeks after birth, we examined reactivity of cerebral arterioles to eNOS- (ADP) and nNOS-dependent (NMDA) agonists in the offspring. We found that in utero exposure to alcohol attenuated responses of cerebral arterioles to ADP and NMDA, but not to nitroglycerin in rats exposed to alcohol in utero. L-NMMA reduced responses to agonists in control rats, but not in rats exposed to alcohol in utero. Treatment of dams with apocynin for the duration of pregnancy rescued the impairment in reactivity to ADP and NMDA in the offspring. Protein expression of NOX-2 and NOX-4 was increased in alcohol rats compared to control rats. We also found an increase in superoxide levels in the cortex of rats exposed to alcohol in utero. Our findings suggest that in utero exposure to alcohol impairs eNOS and nNOS reactivity of cerebral arterioles via a chronic increase in oxidative stress.
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Affiliation(s)
- Sergio G Cananzi
- 1 Department of Cell Biology and Anatomy, and the Center for Cardiovascular Diseases and Sciences, Louisiana State University Health Science Center-Shreveport, Shreveport, LA, USA
| | - William G Mayhan
- 2 Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, USA
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Opatrilova R, Kubatka P, Caprnda M, Büsselberg D, Krasnik V, Vesely P, Saxena S, Ruia S, Mozos I, Rodrigo L, Kruzliak P, dos Santos KG. Nitric oxide in the pathophysiology of retinopathy: evidences from preclinical and clinical researches. Acta Ophthalmol 2018; 96:222-231. [PMID: 28391624 DOI: 10.1111/aos.13384] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/12/2016] [Indexed: 12/11/2022]
Abstract
Retinopathy is the leading cause of blindness and visual disability in working-aged people. The pathogenesis of retinopathy is an actual and still open query. Alterations contributing to oxidative and nitrosative stress, including elevated nitric oxide and superoxide production, changes in the expression of different isoforms of nitric oxide synthase or endogenous antioxidant system, have been implicated in the mechanisms how this ocular disease develops. In addition, it was documented that renin-angiotensin system has been implicated in the progression of retinopathy. Based on comprehensive preclinical and clinical researches in this area, the role of above-mentioned factors in the pathogenesis of diabetic retinopathy, hypertensive retinopathy and ischaemic proliferative retinopathy is reviewed in this study. Moreover, the genetic susceptibility factors involved in the development of the retinopathy and possible strategies that utilize antioxidants as additive therapy are also highlighted here.
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Affiliation(s)
- Radka Opatrilova
- Department of Chemical Drugs; Faculty of Pharmacy; University of Veterinary and Pharmaceutical Sciences; Brno Czech Republic
| | - Peter Kubatka
- Department of Medical Biology; Jessenius Faculty of Medicine; Comenius University in Bratislava; Martin Slovak Republic
- Division of Oncology; Biomedical Center Martin; Jessenius Faculty of Medicine; Comenius University in Bratislava; Martin Slovak Republic
| | - Martin Caprnda
- 2nd Department of Internal Medicine; Faculty of Pharmacy; Comenius University; Bratislava Slovakia
| | | | - Vladimir Krasnik
- Department of Ophthalmology; Faculty of Medicine; Comenius University; Bratislava Slovakia
| | | | - Sandeep Saxena
- Retina Service; Department of Ophthalmology; King George's Medical University; Lucknow India
| | - Surabhi Ruia
- Retina Service; Department of Ophthalmology; King George's Medical University; Lucknow India
| | - Ioana Mozos
- Department of Functional Sciences; “Victor Babes” University of Medicine and Pharmacy; Timisoara Romania
| | - Luis Rodrigo
- Faculty of Medicine; University of Oviedo; Central University Hospital of Asturias (HUCA); Oviedo Spain
| | - Peter Kruzliak
- Department of Chemical Drugs; Faculty of Pharmacy; University of Veterinary and Pharmaceutical Sciences; Brno Czech Republic
| | - Katia Goncalves dos Santos
- Laboratory of Human Molecular Genetics; Universidade Luterana do Brasil; Canoas Brazil
- Experimental and Molecular Cardiovascular Laboratory; Hospital de Clínicas de Porto Alegre; Porto Alegre Brazil
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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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13
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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] [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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Hein TW, Xu W, Xu X, Kuo L. Acute and Chronic Hyperglycemia Elicit JIP1/JNK-Mediated Endothelial Vasodilator Dysfunction of Retinal Arterioles. Invest Ophthalmol Vis Sci 2017; 57:4333-40. [PMID: 27556216 PMCID: PMC5015966 DOI: 10.1167/iovs.16-19990] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Hyperglycemia, a hallmark of diabetes mellitus, is associated with retinal inflammation and impairment of endothelium-dependent nitric oxide (NO)–mediated dilation of retinal arterioles. However, molecular mechanisms involved in this diminished endothelial vasodilator function remain unclear. We examined whether inflammatory stress-activated kinases, c-Jun N-terminal kinase (JNK) and p38, contribute to retinal arteriolar dysfunction during exposure to acute and chronic hyperglycemia. Methods Retinal arterioles were isolated from streptozocin-induced diabetic pigs (2 weeks; chronic hyperglycemia, 471 ± 23 mg/dL) or age-matched control pigs (euglycemia, 79 ± 5 mg/dL), and then cannulated and pressurized for vasoreactivity study. For acute hyperglycemia study, vessels from nondiabetic pigs were exposed intraluminally to high glucose (25 mM ≈ 450 mg/dL) for 2 hours, and normal glucose (5 mM ≈ 90 mg/dL) served as the control. Results Endothelium-dependent vasodilation to bradykinin was reduced in a similar manner after exposure to acute or chronic hyperglycemia. Administration of NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) nearly abolished vasodilations either in control (euglycemia and normal glucose) or hyperglycemic (acute and chronic) vessels. Treatment of either acute or chronic hyperglycemic vessels with JNK inhibitor SP600125 or JNK-interacting protein-1 (JIP1) inhibitor BI-78D3, but not p38 inhibitor SB203580, preserved bradykinin-induced dilation in an L-NAME–sensitive manner. By contrast, endothelium-independent vasodilation to sodium nitroprusside was unaffected by acute or chronic hyperglycemia. Conclusions Activation of JIP1/JNK signaling in retinal arterioles during exposure to acute or chronic hyperglycemia leads to selective impairment of endothelium-dependent NO-mediated dilation. Therapeutic targeting of the vascular JNK pathway may improve retinal endothelial vasodilator function during early diabetes.
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Affiliation(s)
- Travis W Hein
- Department of Surgery, Baylor Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Wenjuan Xu
- Department of Surgery, Baylor Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Xin Xu
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
| | - Lih Kuo
- Department of Surgery, Baylor Scott & White Eye Institute, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States 2Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, Texas, United States
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Skov Jensen P, Aalkjaer C, Bek T. Differential effects of nitric oxide and cyclo-oxygenase inhibition on the diameter of porcine retinal vessels with different caliber during hypoxia ex vivo. Exp Eye Res 2017; 160:38-44. [PMID: 28395971 DOI: 10.1016/j.exer.2017.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/25/2017] [Accepted: 04/06/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND Hypoxia induced relaxation of larger retinal arterioles has been shown to be mediated by nitric oxide (NO) and cyclo-oxygenase (COX) products both in vivo and in vitro. However, the involvement of smaller retinal vessels in the response is unknown. Therefore, the purpose of the present study was to investigate the effect of blocking the synthesis of NO and COX on hypoxia induced changes in the diameter of smaller porcine retinal vessels at different branching level. METHODS Porcine hemiretinas were mounted in a tissue chamber and were constricted with the prostaglandin agonist U46619. Changes in the diameter of arterioles, pre-capillary arterioles and capillaries were studied during hypoxia, in the presence of the COX inhibitor ibuprofen and the NO synthase inhibitor L-NAME. RESULTS In the presence of L-NAME hypoxia induced dilatation was significantly smaller in arterioles and capillaries than in precapillary arterioles (p < 0.04), whereas in the presence of ibuprofen the dilatation was significantly smaller in capillaries and pre-capillary arterioles than in arterioles (p < 0.04). CONCLUSIONS The mechanisms underlying hypoxia induced dilatation differ among smaller porcine retinal vessels with different caliber ex vivo. This may reflect differences in the responses of retinal vessels to changes in metabolism, and may point to possible targets for pharmacological intervention on the diameter of retinal vessels with different caliber in vivo.
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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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