1
|
Biswas A, Choudhury AD, Agrawal S, Bisen AC, Sanap SN, Verma SK, Kumar M, Mishra A, Kumar S, Chauhan M, Bhatta RS. Recent Insights into the Etiopathogenesis of Diabetic Retinopathy and Its Management. J Ocul Pharmacol Ther 2024; 40:13-33. [PMID: 37733327 DOI: 10.1089/jop.2023.0068] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023] Open
Abstract
Purpose: Diabetic retinopathy (DR) is a microvascular retinal disease associated with chronic diabetes mellitus, characterized by the damage of blood vessels in the eye. It is projected to become the leading cause of blindness, given the increasing burden of the diabetic population worldwide. The diagnosis and management of DR pose significant challenges for physicians because of the involvement of multiple biochemical pathways and the complexity of ocular tissues. This review aims to provide a comprehensive understanding of the molecular pathways implicated in the pathogenesis of DR, including the polyo pathway, hexosamine pathway, protein kinase C (PKC), JAK/STAT signaling pathways, and the renin-angiotensin system (RAS). Methods: Academic databases such as PubMed, Scopus, Google Scholar and Web of Science was systematically searched using a carefully constructed search strategy incorporating keywords like "Diabetic Retinopathy," "Molecular Pathways," "Pharmacological Treatments," and "Clinical Trials" to identify relevant literature for the comprehensive review. Results: In addition to activating other inflammatory cascades, these pathways contribute to the generation of oxidative stress within the retina. Furthermore, it aims to explore the existing pharmacotherapy options available for the treatment of DR. In addition to conventional pharmacological therapies such as corticosteroids, antivascular endothelial growth factors, and nonsteroidal anti-inflammatory drugs (NSAIDs), this review highlights the potential of repurposed drugs, phyto-pharmaceuticals, and novel pipeline drugs currently undergoing various stages of clinical trials. Conclusion: Overall, this review serves as a technical exploration of the complex nature of DR, highlighting both established and emerging molecular pathways implicated in its pathogenesis. Furthermore, it delves into the available pharmacological treatments, as well as the promising repurposed drugs, phyto-pharmaceuticals, and novel drugs currently being evaluated in clinical trials, with a focus on their specific mechanisms of action.
Collapse
Affiliation(s)
- Arpon Biswas
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Jawaharlal Nehru University, New Delhi, India
| | - Abhijit Deb Choudhury
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Jawaharlal Nehru University, New Delhi, India
| | - Sristi Agrawal
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Amol Chhatrapati Bisen
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Sachin Nashik Sanap
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Sarvesh Kumar Verma
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Jawaharlal Nehru University, New Delhi, India
| | - Mukesh Kumar
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Jawaharlal Nehru University, New Delhi, India
| | - Anjali Mishra
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Shivansh Kumar
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Mridula Chauhan
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Rabi Sankar Bhatta
- Pharmaceutics and Pharmacokinetic Division, CSIR-Central Drug Research Institute, Lucknow, India
| |
Collapse
|
2
|
Martínez-Alberquilla I, Gasull X, Pérez-Luna P, Seco-Mera R, Ruiz-Alcocer J, Crooke A. Neutrophils and neutrophil extracellular trap components: Emerging biomarkers and therapeutic targets for age-related eye diseases. Ageing Res Rev 2022; 74:101553. [PMID: 34971794 DOI: 10.1016/j.arr.2021.101553] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/17/2021] [Accepted: 12/23/2021] [Indexed: 12/14/2022]
Abstract
Age-related eye diseases, including dry eye, glaucoma, age-related macular degeneration, and diabetic retinopathy, represent a major global health issue based on their increasing prevalence and disabling action. Unraveling the molecular mechanisms underlying these diseases will provide novel opportunities to reduce the burden of age-related eye diseases and improve eye health, contributing to sustainable development goals achievement. The impairment of neutrophil extracellular traps formation/degradation processes seems to be one of these mechanisms. These traps formed by a meshwork of DNA and neutrophil cytosolic granule proteins may exacerbate the inflammatory response promoting chronic inflammation, a pivotal cause of age-related diseases. In this review, we describe current findings that suggest the role of neutrophils and their traps in the pathogenesis of the above-mentioned age-related eye diseases. Furthermore, we discuss why these cells and their constituents could be biomarkers and therapeutic targets for dry eye, glaucoma, age-related macular degeneration, and diabetic retinopathy. We also examine the therapeutic potential of some neutrophil function modulators and provide several recommendations for future research in age-related eye diseases.
Collapse
Affiliation(s)
- Irene Martínez-Alberquilla
- Department of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain; Clinical and Experimental Eye Research Group, UCM 971009, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Xavier Gasull
- Neurophysiology Laboratory, Department of Biomedicine, Medical School, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Patricia Pérez-Luna
- Department of Biochemistry and Molecular Biology, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Rubén Seco-Mera
- Department of Biochemistry and Molecular Biology, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Javier Ruiz-Alcocer
- Department of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain; Clinical and Experimental Eye Research Group, UCM 971009, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Almudena Crooke
- Department of Biochemistry and Molecular Biology, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain; Clinical and Experimental Eye Research Group, UCM 971009, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain.
| |
Collapse
|
3
|
Shivashankar G, Lim JC, Acosta ML. Proinflammatory cytokines trigger biochemical and neurochemical changes in mouse retinal explants exposed to hyperglycemic conditions. Mol Vis 2020; 26:277-290. [PMID: 32300272 PMCID: PMC7155896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 04/09/2020] [Indexed: 12/04/2022] Open
Abstract
PURPOSE Diabetic retinopathy (DR) is one of the most frequent complications of diabetes affecting the retina and eventually causing vision impairment. Emerging evidence suggests that inflammation plays a vital role in DR progression. In this study, we evaluated the early biochemical and neurochemical changes in mouse retinal explants to understand the contribution of proinflammatory cytokines to disease progression. METHODS DR was modeled in vitro by incubating mouse retinal explants in a physiological buffer supplemented with high glucose and the proinflammatory cytokines TNF-α and IL-1β. Key metabolites of retinal energy metabolism, including glucose, lactate, ATP, glutamate, glutamine, and enzymes supporting retinal ATP levels were assessed 40 min after the application of high glucose and proinflammatory cytokines. As retinal energy metabolism is tightly coupled to retinal neurochemistry, we also determined the short-term effect on the amino acid distribution of glutamate, gamma aminobutyric acid (GABA), glutamine, and glycine. RESULTS The results indicated that the combined application of high glucose and proinflammatory cytokines increased retinal glucose, lactate, and ATP levels, and decreased retinal glutamate, without affecting glutamine levels or the enzymes supporting ATP levels. Moreover, we observed a statistically significant increase in ATP and glutamate release. Correspondingly, statistically significant alterations in amino acid distribution were observed in retinal explants coexposed to high glucose and proinflammatory cytokines. CONCLUSIONS These data suggest that short-term exposure to proinflammatory cytokines contributes to the early biochemical and neurochemical changes caused by hyperglycemia, by affecting retinal energy metabolism and amino acid distribution. These data are consistent with the idea that early intervention to prevent inflammation-triggered loss of metabolic homeostasis in patients with diabetes is necessary to prevent DR progression.
Collapse
Affiliation(s)
- Gaganashree Shivashankar
- School of Optometry and Vision Science and New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Julie C. Lim
- Department of Physiology, School of Medical and Health Sciences and New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Monica L. Acosta
- School of Optometry and Vision Science and New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| |
Collapse
|
4
|
Santiago AR, Madeira MH, Boia R, Aires ID, Rodrigues-Neves AC, Santos PF, Ambrósio AF. Keep an eye on adenosine: Its role in retinal inflammation. Pharmacol Ther 2020; 210:107513. [PMID: 32109489 DOI: 10.1016/j.pharmthera.2020.107513] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adenosine is an endogenous purine nucleoside ubiquitously distributed throughout the body that interacts with G protein-coupled receptors, classified in four subtypes: A1R, A2AR, A2BR and A3R. Among the plethora of functions of adenosine, it has been increasingly recognized as a key mediator of the immune response. Neuroinflammation is a feature of chronic neurodegenerative diseases and contributes to the pathophysiology of several retinal degenerative diseases. Animal models of retinal diseases are helping to elucidate the regulatory roles of adenosine receptors in the development and progression of those diseases. Mounting evidence demonstrates that the adenosinergic system is altered in the retina during pathological conditions, compromising retinal physiology. This review focuses on the roles played by adenosine and the elements of the adenosinergic system (receptors, enzymes, transporters) in the neuroinflammatory processes occurring in the retina. An improved understanding of the molecular and cellular mechanisms of the signalling pathways mediated by adenosine underlying the onset and progression of retinal diseases will pave the way towards the identification of new therapeutic approaches.
Collapse
Affiliation(s)
- Ana Raquel Santiago
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
| | - Maria H Madeira
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal
| | - Raquel Boia
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Inês Dinis Aires
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ana Catarina Rodrigues-Neves
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo Fernando Santos
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - António Francisco Ambrósio
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
| |
Collapse
|
5
|
Aires ID, Madeira MH, Boia R, Rodrigues-Neves AC, Martins JM, Ambrósio AF, Santiago AR. Intravitreal injection of adenosine A 2A receptor antagonist reduces neuroinflammation, vascular leakage and cell death in the retina of diabetic mice. Sci Rep 2019; 9:17207. [PMID: 31748653 PMCID: PMC6868354 DOI: 10.1038/s41598-019-53627-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 11/01/2019] [Indexed: 12/20/2022] Open
Abstract
Diabetic retinopathy is a major complication of diabetes mellitus and a leading cause of blindness. The pathogenesis of diabetic retinopathy is accompanied by chronic low-grade inflammation. Evidence shows that the blockade of adenosine A2A receptors (A2AR) affords protection to the retina through the control of microglia-mediated neuroinflammation. Herein, we investigated the therapeutic potential of an antagonist of A2AR in a model of diabetic retinopathy. Type 1 diabetes was induced in 4–5 months old C57BL/6 J mice with a single intraperitoneal injection streptozotocin. Animals were treated one month after the onset of diabetes. The A2AR antagonist was delivered by intravitreal injection once a week for 4 weeks. Microglia reactivity and inflammatory mediators were increased in the retinas of diabetic animals. The treatment with the A2AR antagonist was able to control microglial reactivity and halt neuroinflammation. Furthermore, the A2AR antagonist rescued retinal vascular leakage, attenuated alterations in retinal thickness, decreased retinal cell death and the loss of retinal ganglion cells induced by diabetes. These results demonstrate that intravitreal injection of the A2AR antagonist controls inflammation, affords protection against cell loss and reduces vascular leakage associated with diabetes, which could be envisaged as a therapeutic approach for the early complications of diabetes in the retina.
Collapse
Affiliation(s)
- Inês Dinis Aires
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal
| | - Maria Helena Madeira
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal
| | - Raquel Boia
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal
| | - Ana Catarina Rodrigues-Neves
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal
| | - Joana Margarida Martins
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal
| | - António Francisco Ambrósio
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal
| | - Ana Raquel Santiago
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal. .,CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal. .,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal.
| |
Collapse
|
6
|
Calbiague VM, Vielma AH, Cadiz B, Paquet‐Durand F, Schmachtenberg O. Physiological assessment of high glucose neurotoxicity in mouse and rat retinal explants. J Comp Neurol 2019; 528:989-1002. [DOI: 10.1002/cne.24805] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/09/2019] [Accepted: 10/20/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Víctor M. Calbiague
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
- Programa Doctorado en Ciencias, mención Neurociencias Universidad de Valparaíso Valparaíso Chile
| | - Alex H. Vielma
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
| | - Bárbara Cadiz
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
| | - Francois Paquet‐Durand
- Cell Death Mechanism Group Institute for Ophthalmic Research, University of Tübingen Tübingen Germany
| | - Oliver Schmachtenberg
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
| |
Collapse
|
7
|
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: 0.5] [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.
Collapse
Affiliation(s)
- Toke Bek
- Department of Ophthalmology Aarhus University Hospital Aarhus C DK‐8000 Denmark
| |
Collapse
|
8
|
Borea PA, Gessi S, Merighi S, Vincenzi F, Varani K. Pharmacology of Adenosine Receptors: The State of the Art. Physiol Rev 2018; 98:1591-1625. [PMID: 29848236 DOI: 10.1152/physrev.00049.2017] [Citation(s) in RCA: 496] [Impact Index Per Article: 70.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Adenosine is a ubiquitous endogenous autacoid whose effects are triggered through the enrollment of four G protein-coupled receptors: A1, A2A, A2B, and A3. Due to the rapid generation of adenosine from cellular metabolism, and the widespread distribution of its receptor subtypes in almost all organs and tissues, this nucleoside induces a multitude of physiopathological effects, regulating central nervous, cardiovascular, peripheral, and immune systems. It is becoming clear that the expression patterns of adenosine receptors vary among cell types, lending weight to the idea that they may be both markers of pathologies and useful targets for novel drugs. This review offers an overview of current knowledge on adenosine receptors, including their characteristic structural features, molecular interactions and cellular functions, as well as their essential roles in pain, cancer, and neurodegenerative, inflammatory, and autoimmune diseases. Finally, we highlight the latest findings on molecules capable of targeting adenosine receptors and report which stage of drug development they have reached.
Collapse
Affiliation(s)
- Pier Andrea Borea
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Stefania Gessi
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Stefania Merighi
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Fabrizio Vincenzi
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| | - Katia Varani
- Department of Medical Sciences, University of Ferrara , Ferrara , Italy
| |
Collapse
|
9
|
Beach KM, Hung LF, Arumugam B, Smith EL, Ostrin LA. Adenosine receptor distribution in Rhesus monkey ocular tissue. Exp Eye Res 2018; 174:40-50. [PMID: 29792846 DOI: 10.1016/j.exer.2018.05.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/26/2018] [Accepted: 05/20/2018] [Indexed: 02/06/2023]
Abstract
Adenosine receptor (ADOR) antagonists, such as 7-methylxanthine (7-MX), have been shown to slow myopia progression in humans and animal models. Adenosine receptors are found throughout the body, and regulate the release of neurotransmitters such as dopamine and glutamate. However, the role of adenosine in eye growth is unclear. Evidence suggests that 7-MX increases scleral collagen fibril diameter, hence preventing axial elongation. This study used immunohistochemistry (IHC) and reverse-transcription quantitative polymerase chain reaction (RT-qPCR) to examine the distribution of the four ADORs in the normal monkey eye to help elucidate potential mechanisms of action. Eyes were enucleated from six Rhesus monkeys. Anterior segments and eyecups were separated into components and flash-frozen for RNA extraction or fixed in 4% paraformaldehyde and processed for immunohistochemistry against ADORA1, ADORA2a, ADORA2b, and ADORA3. RNA was reverse-transcribed, and qPCR was performed using custom primers. Relative gene expression was calculated using the ΔΔCt method normalizing to liver expression, and statistical analysis was performed using Relative Expression Software Tool. ADORA1 immunostaining was highest in the iris sphincter muscle, trabecular meshwork, ciliary epithelium, and retinal nerve fiber layer. ADORA2a immunostaining was highest in the corneal epithelium, trabecular meshwork, ciliary epithelium, retinal nerve fiber layer, and scleral fibroblasts. ADORA2b immunostaining was highest in corneal basal epithelium, limbal stem cells, iris sphincter, ciliary muscle, ciliary epithelium, choroid, isolated retinal ganglion cells and scattered scleral fibroblasts. ADORA3 immunostaining was highest in the iris sphincter, ciliary muscle, ciliary epithelium, choroid, isolated retinal ganglion cells, and scleral fibroblasts. Compared to liver mRNA, ADORA1 mRNA was significantly higher in the brain, retina and choroid, and significantly lower in the iris/ciliary body. ADORA2a expression was higher in brain and retina, ADORA2b expression was higher in retina, and ADORA3 was higher in the choroid. In conclusion, immunohistochemistry and RT-qPCR indicated differential patterns of expression of the four adenosine receptors in the ocular tissues of the normal non-human primate. The presence of ADORs in scleral fibroblasts and the choroid may support mechanisms by which ADOR antagonists prevent myopia. The potential effects of ADOR inhibition on both anterior and posterior ocular structures warrant investigation.
Collapse
Affiliation(s)
- Krista M Beach
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Li-Fang Hung
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Baskar Arumugam
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Earl L Smith
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Lisa A Ostrin
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA.
| |
Collapse
|
10
|
Burnstock G. Purinergic Signalling: Therapeutic Developments. Front Pharmacol 2017; 8:661. [PMID: 28993732 PMCID: PMC5622197 DOI: 10.3389/fphar.2017.00661] [Citation(s) in RCA: 282] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/05/2017] [Indexed: 12/15/2022] Open
Abstract
Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990's when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson's disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical SchoolLondon, United Kingdom
- Department of Pharmacology and Therapeutics, The University of Melbourne, MelbourneVIC, Australia
| |
Collapse
|
11
|
Borea PA, Gessi S, Merighi S, Vincenzi F, Varani K. Pathological overproduction: the bad side of adenosine. Br J Pharmacol 2017; 174:1945-1960. [PMID: 28252203 PMCID: PMC6398520 DOI: 10.1111/bph.13763] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 12/12/2022] Open
Abstract
Adenosine is an endogenous ubiquitous purine nucleoside, which is increased by hypoxia, ischaemia and tissue damage and mediates a number of physiopathological effects by interacting with four GPCRs, identified as A1 , A2A , A2B and A3 . Physiological and acutely increased adenosine is mostly associated with beneficial effects that include vasodilatation and a decrease in inflammation. In contrast, chronic overproduction of adenosine occurs in important pathological states, where long-lasting increases in the nucleoside levels are responsible for the bad side of adenosine associated with chronic inflammation, fibrosis and organ damage. In this review, we describe and critically discuss the pathological overproduction of adenosine and analyse when, where and how adenosine exerts its detrimental effects throughout the body.
Collapse
Affiliation(s)
- Pier Andrea Borea
- Department of Medical SciencesUniversity of FerraraFerrara44121Italy
| | - Stefania Gessi
- Department of Medical SciencesUniversity of FerraraFerrara44121Italy
| | - Stefania Merighi
- Department of Medical SciencesUniversity of FerraraFerrara44121Italy
| | - Fabrizio Vincenzi
- Department of Medical SciencesUniversity of FerraraFerrara44121Italy
| | - Katia Varani
- Department of Medical SciencesUniversity of FerraraFerrara44121Italy
| |
Collapse
|
12
|
Stolf AM, Cardoso CC, Acco A. Effects of Silymarin on Diabetes Mellitus Complications: A Review. Phytother Res 2017; 31:366-374. [PMID: 28124457 DOI: 10.1002/ptr.5768] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/16/2016] [Accepted: 12/17/2016] [Indexed: 12/19/2022]
Abstract
Diabetes mellitus is a common metabolic disorder that is caused by a deficit in the production of (type 1) or response to (type 2) insulin. Diabetes mellitus is characterized by a state of chronic hyperglycemia and such symptoms as weight loss, thirst, polyuria, and blurred vision. These disturbances represent one of the major causes of morbidity and mortality nowadays, despite available treatments, such as insulin, insulin secretagogues, insulin sensitizers, and oral hypoglycemic agents. However, many efforts have been made to discover new drugs for diabetes treatment, including medicinal plant extracts. Silymarin is a powder extract of the seeds from Silybum marianum, a plant from the Asteraceae family. The major active ingredients include four isomers: silybin, isosilybin, silychristin, and silydianin. Silymarin is indicated for the treatment of hepatic disorders, such as cirrhosis, chronic hepatitis, and gallstones. Moreover, several studies of other pathologies, including diabetes, sepsis, osteoporosis, arthritis, hypercholesterolemia, cancer, viral infections, and Alzheimer's and Parkinson's diseases, have tested the effects of silymarin and reported promising results. This article reviews data from clinical, in vivo, and in vitro studies on the use of silymarin, with a focus on the complications of diabetes, including nephropathy, neuropathy, healing delays, oxidative stress, hepatotoxicity, and cardiomyopathy. Copyright © 2017 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Aline Maria Stolf
- Department of Pharmacology, Federal University of Paraná, Curitiba, PR, Brazil
| | | | - Alexandra Acco
- Department of Pharmacology, Federal University of Paraná, Curitiba, PR, Brazil
| |
Collapse
|
13
|
Jacobson KA, Civan MM. Ocular Purine Receptors as Drug Targets in the Eye. J Ocul Pharmacol Ther 2016; 32:534-547. [PMID: 27574786 PMCID: PMC5069731 DOI: 10.1089/jop.2016.0090] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/13/2016] [Indexed: 02/06/2023] Open
Abstract
Agonists and antagonists of various subtypes of G protein coupled adenosine receptors (ARs), P2Y receptors (P2YRs), and ATP-gated P2X receptor ion channels (P2XRs) are under consideration as agents for the treatment of ocular diseases, including glaucoma and dry eye. Numerous nucleoside and nonnucleoside modulators of the receptors are available as research tools and potential therapeutic molecules. Three of the 4 subtypes of ARs have been exploited with clinical candidate molecules for treatment of the eye: A1, A2A, and A3. An A1AR agonist is in clinical trials for glaucoma, A2AAR reduces neuroinflammation, A3AR protects retinal ganglion cells from apoptosis, and both A3AR agonists and antagonists had been reported to lower intraocular pressure (IOP). Extracellular concentrations of endogenous nucleotides, including dinucleoside polyphosphates, are increased in pathological states, activating P2Y and P2XRs throughout the eye. P2YR agonists, including P2Y2 and P2Y6, lower IOP. Antagonists of the P2X7R prevent the ATP-induced neuronal apoptosis in the retina. Thus, modulators of the purinome in the eye might be a source of new therapies for ocular diseases.
Collapse
Affiliation(s)
- Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Mortimer M. Civan
- Departments of Physiology and Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| |
Collapse
|