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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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Daxer B, Radner W, Fischer F, Cocoșilă AL, Ettl A. Aetiology, Diagnosis and Treatment of Arterial Occlusions of the Retina-A Narrative Review. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:526. [PMID: 38674172 PMCID: PMC11052062 DOI: 10.3390/medicina60040526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024]
Abstract
Arterial occlusions of the retina are potentially sight-threatening diseases which often result in profound visual loss. The aim of this narrative review is to provide an overview of the aetiology, discuss major risk factors, describe the management and systemic assessments and evaluate existing therapies. For this review, an extensive literature search in PubMed was performed. Emboli from the heart or the carotid arteries can cause ophthalmic artery occlusion (OAO), central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO). Most patients with arterial occlusions have vascular risk factors such as arterial hypertension, hyperhomocysteinaemia, carotid stenosis and atrial fibrillation, which also increase the risk of cerebral stroke and myocardial infarction. Therapies such as ocular massage, thrombolysis and anterior chamber paracentesis have been suggested but are still equivocal. However, it is evident that retinal artery occlusion should be immediately treated and accompanied by interdisciplinary collaboration, since early diagnosis and the proper treatment of possible risk factors are important to reduce the risk of further damage, recurrences, other vascular diseases and mortality.
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Affiliation(s)
- Barbara Daxer
- Karl Landsteiner University of Health Sciences, Dr. Karl-Dorrek-Straße 30, 3500 Krems, Austria
- Department of Ophthalmology and Orbital Surgery, University Hospital St. Pölten, Dunantplatz 1, 3100 St. Pölten, Austria
| | - Wolfgang Radner
- Karl Landsteiner University of Health Sciences, Dr. Karl-Dorrek-Straße 30, 3500 Krems, Austria
- Department of Ophthalmology and Orbital Surgery, University Hospital St. Pölten, Dunantplatz 1, 3100 St. Pölten, Austria
- Austrian Academy of Ophthalmology, Mollgasse 11, 1180 Vienna, Austria
| | - Florian Fischer
- Karl Landsteiner University of Health Sciences, Dr. Karl-Dorrek-Straße 30, 3500 Krems, Austria
- Department of Ophthalmology and Orbital Surgery, University Hospital St. Pölten, Dunantplatz 1, 3100 St. Pölten, Austria
| | - Andreea-Liliana Cocoșilă
- Faculty of Medicine and Pharmacy, University of Oradea, 1 Decembrie Square 10, 410068 Oradea, Romania
| | - Armin Ettl
- Karl Landsteiner University of Health Sciences, Dr. Karl-Dorrek-Straße 30, 3500 Krems, Austria
- Department of Ophthalmology and Orbital Surgery, University Hospital St. Pölten, Dunantplatz 1, 3100 St. Pölten, Austria
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Križaj D, Cordeiro S, Strauß O. Retinal TRP channels: Cell-type-specific regulators of retinal homeostasis and multimodal integration. Prog Retin Eye Res 2023; 92:101114. [PMID: 36163161 PMCID: PMC9897210 DOI: 10.1016/j.preteyeres.2022.101114] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 02/05/2023]
Abstract
Transient receptor potential (TRP) channels are a widely expressed family of 28 evolutionarily conserved cationic ion channels that operate as primary detectors of chemical and physical stimuli and secondary effectors of metabotropic and ionotropic receptors. In vertebrates, the channels are grouped into six related families: TRPC, TRPV, TRPM, TRPA, TRPML, and TRPP. As sensory transducers, TRP channels are ubiquitously expressed across the body and the CNS, mediating critical functions in mechanosensation, nociception, chemosensing, thermosensing, and phototransduction. This article surveys current knowledge about the expression and function of the TRP family in vertebrate retinas, which, while dedicated to transduction and transmission of visual information, are highly susceptible to non-visual stimuli. Every retinal cell expresses multiple TRP subunits, with recent evidence establishing their critical roles in paradigmatic aspects of vertebrate vision that include TRPM1-dependent transduction of ON bipolar signaling, TRPC6/7-mediated ganglion cell phototransduction, TRP/TRPL phototransduction in Drosophila and TRPV4-dependent osmoregulation, mechanotransduction, and regulation of inner and outer blood-retina barriers. TRP channels tune light-dependent and independent functions of retinal circuits by modulating the intracellular concentration of the 2nd messenger calcium, with emerging evidence implicating specific subunits in the pathogenesis of debilitating diseases such as glaucoma, ocular trauma, diabetic retinopathy, and ischemia. Elucidation of TRP channel involvement in retinal biology will yield rewards in terms of fundamental understanding of vertebrate vision and therapeutic targeting to treat diseases caused by channel dysfunction or over-activation.
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Affiliation(s)
- David Križaj
- Departments of Ophthalmology, Neurobiology, and Bioengineering, University of Utah, Salt Lake City, USA
| | - Soenke Cordeiro
- Institute of Physiology, Faculty of Medicine, Christian-Albrechts-University Kiel, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a Corporate Member of Freie Universität, Humboldt-University, The Berlin Institute of Health, Berlin, Germany.
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FEATURES OF VASCULATURE IN PATIENTS WITH RETINA ARTERIAL MACROANEURYSM USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retina 2023; 43:130-137. [PMID: 36542083 DOI: 10.1097/iae.0000000000003637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/22/2022] [Indexed: 12/24/2022]
Abstract
PURPOSE To assess morphologic characteristics of retinal arterial macroaneurysm (RAM) and their vascular changes using optical coherence tomography angiography (OCTA). METHODS This observational study included 31 eyes of 29 participants diagnosed with RAM based on fundus fluorescein angiography in Tianjin Medical University Eye Hospital. Multimodal imaging modalities, including fundus photography, fluorescein angiography, and OCTA, were used to examine RAMs. The demographic and clinical characteristics of the RAMs were recorded. RESULTS Depending on the fundus fluorescein angiography examination, 40 cases of RAM were confirmed in 29 patients. Twenty-three patients were female (79%), and six patients were male (21%). Two patients had binocular RAM, and four eyes had more than one RAMs. Relying on the OCTA technology, RAMs have four different vascular morphology types (i.e., distended, meshed, malformed, and occult types). In the distended type, round or encircled thrombi caused asymmetrical or symmetrical distention of retinal arteriolar, leading to separate true lumen and false thrombus lumen in RAM. In the meshed type, the meshed or dendritic vascular network around the RAM was likely to be the neovascularization due to the ischemia and hypoxia of the arteriolar wall. Finally, in the malformed and occult type, the RAM usually regressed, and the retinal arterioles were remodeled to distorted or normal arterioles accompanied by capillary degradation. CONCLUSION Relying on the OCTA technology, we found that the RAMs have four different types of vascular morphology. Each group of RAM has different vascular features. The application of OCTA in patients with RAM furthers our understanding of the vasculature of RAMs.
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O’Hare M, Esquiva G, McGahon MK, Hombrebueno JMR, Augustine J, Canning P, Edgar KS, Barabas P, Friedel T, Cincolà P, Henry J, Mayne K, Ferrin H, Stitt AW, Lyons TJ, Brazil DP, Grieve DJ, McGeown JG, Curtis TM. Loss of TRPV2-mediated blood flow autoregulation recapitulates diabetic retinopathy in rats. JCI Insight 2022; 7:e155128. [PMID: 36134661 PMCID: PMC9675469 DOI: 10.1172/jci.insight.155128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 08/10/2022] [Indexed: 11/17/2022] Open
Abstract
Loss of retinal blood flow autoregulation is an early feature of diabetes that precedes the development of clinically recognizable diabetic retinopathy (DR). Retinal blood flow autoregulation is mediated by the myogenic response of the retinal arterial vessels, a process that is initiated by the stretch‑dependent activation of TRPV2 channels on the retinal vascular smooth muscle cells (VSMCs). Here, we show that the impaired myogenic reaction of retinal arterioles from diabetic animals is associated with a complete loss of stretch‑dependent TRPV2 current activity on the retinal VSMCs. This effect could be attributed, in part, to TRPV2 channel downregulation, a phenomenon that was also evident in human retinal VSMCs from diabetic donors. We also demonstrate that TRPV2 heterozygous rats, a nondiabetic model of impaired myogenic reactivity and blood flow autoregulation in the retina, develop a range of microvascular, glial, and neuronal lesions resembling those observed in DR, including neovascular complexes. No overt kidney pathology was observed in these animals. Our data suggest that TRPV2 dysfunction underlies the loss of retinal blood flow autoregulation in diabetes and provide strong support for the hypothesis that autoregulatory deficits are involved in the pathogenesis of DR.
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Affiliation(s)
- Michael O’Hare
- Wellcome-Wolfson Institute for Experimental Medicine and
| | - Gema Esquiva
- Wellcome-Wolfson Institute for Experimental Medicine and
| | - Mary K. McGahon
- Wellcome-Wolfson Institute for Experimental Medicine and
- Centre for Biomedical Sciences Education, Queen’s University Belfast, Belfast, United Kingdom
| | | | - Josy Augustine
- Wellcome-Wolfson Institute for Experimental Medicine and
| | - Paul Canning
- Wellcome-Wolfson Institute for Experimental Medicine and
| | - Kevin S. Edgar
- Wellcome-Wolfson Institute for Experimental Medicine and
| | - Peter Barabas
- Wellcome-Wolfson Institute for Experimental Medicine and
| | - Thomas Friedel
- Wellcome-Wolfson Institute for Experimental Medicine and
| | | | - Jennifer Henry
- Wellcome-Wolfson Institute for Experimental Medicine and
- Centre for Biomedical Sciences Education, Queen’s University Belfast, Belfast, United Kingdom
| | - Katie Mayne
- Wellcome-Wolfson Institute for Experimental Medicine and
- Centre for Biomedical Sciences Education, Queen’s University Belfast, Belfast, United Kingdom
| | - Hannah Ferrin
- Wellcome-Wolfson Institute for Experimental Medicine and
- Centre for Biomedical Sciences Education, Queen’s University Belfast, Belfast, United Kingdom
| | - Alan W. Stitt
- Wellcome-Wolfson Institute for Experimental Medicine and
| | | | | | | | | | - Tim M. Curtis
- Wellcome-Wolfson Institute for Experimental Medicine and
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Streese L, Vaes A, Infanger D, Roth R, Hanssen H. Quantification of Retinal Vessel Myogenic Constriction in Response to Blood Pressure Peaks: Implications for Flicker Light-Induced Dilatation. Front Physiol 2021; 12:608985. [PMID: 33679432 PMCID: PMC7929982 DOI: 10.3389/fphys.2021.608985] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/25/2021] [Indexed: 01/10/2023] Open
Abstract
Background/Aims Flicker-light induced retinal vessel dilatation (FID), a marker of microvascular endothelial function, has been shown to be blunted in sedentary cardiovascular risk patients (SR) as well as healthy physically active individuals (HA). This study aimed to quantify the retinal myogenic response to blood pressure (BP) peaks and its effects on consecutive FID for differentiation of microvascular health. Methods Ten HA and eleven SR with a previously established restriction of arteriolar FID (aFID) (<2.2%) were invited in order to assess BP-induced myogenic constriction following a standardized handgrip task and a consecutive FID. BP was measured beat-to-beat. Results The complete dataset of nine HA (3 female, mean age 65 years) and nine SR (5 female, mean age 61 years) individuals was analyzed. The central retinal arteriolar diameter equivalent (CRAE) was 183 ± 11 μm for HA and 176 ± 20 μm for SR. Initial baseline aFID was 1.6 ± 0.4% in HA and 1.6 ± 0.7% in SR. Systolic (p = 0.334) and diastolic (p = 0.245) BP increase following the handgrip task was in the range of 20–30% and comparable in both groups. BP increase was followed by a significantly higher arteriolar (−2.9 ± 1.3% vs. −1.3 ± 0.6%, p < 0.01) myogenic constriction in HA compared to SR. Moreover, in the consecutive assessment of FID directly after the BP-induced vessel constriction, aFID (4.1 ± 2.0% vs. 1.6 ± 0.9%, p < 0.01) was higher in HA compared to SR. Conclusion Initial baseline aFID was blunted in HA and SR. Retinal myogenic constriction was impaired in SR compared to HA. The consecutive aFID after BP-induced myogenic constriction recovered in HA but remained blunted in SR. Additional assessment of retinal myogenic constriction needs to be considered to improve CV risk stratification and reduce false-positive findings of endothelial dysfunction in otherwise healthy active individuals. Clinical Trial Registration ClinicalTrials.gov: NCT03986892 (https://clinicaltrials.gov/ct2/show/NCT03986892).
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Affiliation(s)
- Lukas Streese
- Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland
| | - Anja Vaes
- Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland
| | - Denis Infanger
- Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland
| | - Ralf Roth
- Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland
| | - Henner Hanssen
- Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland
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