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Wostyn P, Killer HE. Normal-Tension Glaucoma: A Glymphopathy? Eye Brain 2023; 15:37-44. [PMID: 37056720 PMCID: PMC10086217 DOI: 10.2147/eb.s401306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/07/2023] [Indexed: 04/15/2023] Open
Abstract
Glaucoma is one of the main causes of irreversible blindness in the world. The most common form, primary open-angle glaucoma, is an optic neuropathy that is characterized by a progressive loss of retinal ganglion cells and their axons, leading to structural changes in the optic nerve head and associated visual field defects. Elevated intraocular pressure remains the most important modifiable risk factor for primary open-angle glaucoma. However, a significant proportion of patients develop glaucomatous damage in the absence of increased intraocular pressure, a condition known as normal-tension glaucoma (NTG). The pathophysiology underlying NTG remains unclear. Several studies have revealed that vascular and cerebrospinal fluid (CSF) factors may play significant roles in the development of NTG. Vascular failure caused by functional or structural abnormalities, and compartmentation of the optic nerve subarachnoid space with disturbed CSF dynamics have been shown to be associated with NTG. In the present article, based on the concept of the glymphatic system and observations in patients with NTG, we hypothesize that failure of fluid transport via the glymphatic pathway in the optic nerve may be involved in the pathogenesis of some if not many cases of NTG. According to this hypothesis, vascular and CSF factors may share reduced glymphatic transport and perivascular waste clearance in the optic nerve as a final common pathway leading to the development of NTG. In addition, we speculate that some cases of NTG may reflect glymphatic dysfunction in natural brain aging and central nervous system diseases, such as Alzheimer's disease. Clearly, further studies are needed to gain additional insight into the relative contribution of these factors and conditions to reduced glymphatic transport in the optic nerve.
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Affiliation(s)
- Peter Wostyn
- Department of Psychiatry, PC Sint-Amandus, Beernem, Belgium
- Correspondence: Peter Wostyn, Department of Psychiatry, PC Sint-Amandus, Reigerlostraat 10, Beernem, 8730, Belgium, Tel +32-472713719, Fax +32-50-819720, Email
| | - Hanspeter Esriel Killer
- Department of Biomedicine, University of Basel, Basel, Switzerland
- Augenärzte Zentrum Aarau, Aarau, Switzerland
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2
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Lou B, Zeng L, Gao X, Qian X, Li JJ, Gu X, Liu Z, Liu K, Chen X, Lin X, Zhang F. A single-cell transcriptomic atlas of the human ciliary body. Cell Mol Life Sci 2022; 79:528. [PMID: 36163311 PMCID: PMC9512889 DOI: 10.1007/s00018-022-04559-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/08/2022] [Accepted: 09/12/2022] [Indexed: 12/02/2022]
Abstract
The ciliary body critically contributes to the ocular physiology with multiple responsibilities in the production of aqueous humor, vision accommodation and intraocular immunity. Comparatively little work, however, has revealed the single-cell molecular taxonomy of the human ciliary body required for studying these functionalities. In this study, we report a comprehensive atlas of the cellular and molecular components of human ciliary body as well as their interactions using single-cell RNA sequencing (scRNAseq). Cluster analysis of the transcriptome of 14,563 individual ciliary cells from the eyes of 3 human donors identified 14 distinct cell types, including the ciliary epithelium, smooth muscle, vascular endothelial cell, immune cell and other stromal cell populations. Cell-type discriminative gene markers were also revealed. Unique gene expression patterns essential for ciliary epithelium-mediated aqueous humor inflow and ciliary smooth muscle contractility were identified. Importantly, we discovered the transitional states that probably contribute to the transition of ciliary macrophage into retina microglia and verified no lymphatics in the ciliary body. Moreover, the utilization of CellPhoneDB allowed us to systemically infer cell–cell interactions among diverse ciliary cells including those that potentially participate in the pathogenesis of glaucoma and uveitis. Altogether, these new findings provide insights into the regulation of intraocular pressure, accommodation reflex and immune homeostasis under physiological and pathological conditions.
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Affiliation(s)
- Bingsheng Lou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Lei Zeng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xinbo Gao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xiaobing Qian
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Jing Jing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xinyu Gu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Zheng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Keli Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xun Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xiaofeng Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China.
| | - Feng Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China.
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3
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The essential role of N6-methyladenosine RNA methylation in complex eye diseases. Genes Dis 2022; 10:505-520. [DOI: 10.1016/j.gendis.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/29/2022] [Accepted: 05/08/2022] [Indexed: 11/20/2022] Open
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4
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Hanna J, Yücel YH, Zhou X, Kim N, Irving H, Gupta N. Beta-adrenergic glaucoma drugs reduce lymphatic clearance from the eye: A sequential photoacoustic imaging study. Exp Eye Res 2021; 212:108775. [PMID: 34599970 DOI: 10.1016/j.exer.2021.108775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 09/05/2021] [Accepted: 09/24/2021] [Indexed: 11/20/2022]
Abstract
Our study aims to determine whether the beta-adrenergic system is involved in the regulation of lymphatic drainage from the eye. For this purpose, we assessed the effect of 2 topical beta-adrenergic blockers, timolol and betaxolol, commonly used as glaucoma drugs, on lymphatic clearance of albumin from the aqueous humor to neck lymph nodes. Adult mice were treated with either topical timolol, a non-selective β-blocker, 0.5% (n = 8), or topical betaxolol, a selective β1-adrenergic blocker, 0.5% (n = 6) twice daily for 14 days and compared to respective control groups (n = 5 and n = 7). Changes in lymphatic clearance from the eye were assessed using a quantitative in vivo photoacoustic imaging approach. In all subjects, right eye and neck lymph nodes were longitudinally assessed by sequential photoacoustic imaging just prior to near-infrared dye injection into the anterior chamber of the eye, and 20 min, 2 and 4 h after injection. Repeat measurements of mean pixel intensities (MPIs) of right eyes and nodes were performed at all timepoints. The areas under the curves (AUC) were calculated and the AUC of the treated-group was compared to that of controls using the Mann-Whitney U test. The slopes of MPI of each region of interest over time were compared using the linear mixed model after adjusting for IOP decrease after treatment and other parameters such as sex and body weight. In the timolol-treated group, right neck nodes showed significant decrease in AUC signal intensity compared with controls (P = 0.003), and significant decrease in slope of MPI compared with controls (P = 0.0025). In the betaxolol-treated group, right neck nodes showed significant decrease in AUC signal intensity compared with controls (P = 0.02), and significant decrease in slope of MPI compared with controls (P = 0.0069). Topical treatment with timolol and betaxolol reduced lymphatic clearance of albumin from the aqueous humor to the neck lymph nodes. This finding may be relevant for the management of secondary glaucomas and inflammatory eye disease in which the clearance of accumulated proteins and antigen from the eye is important to disease recovery and sight protection. This study suggests that the beta-adrenergic system plays a role in the regulation of lymphatic clearance from the eye.
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Affiliation(s)
- Joseph Hanna
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute of St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Yeni H Yücel
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute of St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Physics, Faculty of Science, Ryerson University, Toronto, Ontario, Canada; Faculty of Engineering and Architectural Science, Ryerson University, Toronto, Ontario, Canada; Institute of Biomedical Engineering, Science and Technology (iBEST), St. Michael's Hospital, Ryerson University, Toronto, Ontario, Canada
| | - Xun Zhou
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute of St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Nayeon Kim
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute of St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Hyacinth Irving
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute of St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Neeru Gupta
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute of St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Ontario, Canada; Glaucoma and Nerve Protection Unit, St. Michael's Hospital, Toronto, Ontario, Canada.
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5
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Lymphatics in Eye Fluid Homeostasis: Minor Contributors or Significant Actors? BIOLOGY 2021; 10:biology10070582. [PMID: 34201989 PMCID: PMC8301034 DOI: 10.3390/biology10070582] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023]
Abstract
Lymphatic vessels exert major effects on the maintenance of interstitial fluid homeostasis, immune cell trafficking, lipid absorption, tumor progression and metastasis. Recently, novel functional roles for the lymphatic vasculature have emerged, which can be associated with pathological situations. Among them, lymphatics have been proposed to participate in eye aqueous humor drainage, with potential consequences on intraocular pressure, a main risk factor for progression of glaucoma disease. In this review, after the description of eye fluid dynamics, we provide an update on the data concerning the distribution of ocular lymphatics. Particular attention is given to the results of investigations allowing the three dimensional visualization of the ocular surface vasculature, and to the molecular mechanisms that have been characterized to regulate ocular lymphatic vessel development. The studies concerning the potential role of lymphatics in aqueous humor outflow are reported and discussed. We also considered the novel studies mentioning the existence of an ocular glymphatic system which may have, in connection with lymphatics, important repercussions in retinal clearance and in diseases affecting the eye posterior segment. Some remaining unsolved questions and new directions to explore are proposed to improve the knowledge about both lymphatic and glymphatic system interactions with eye fluid homeostasis.
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6
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Dubin A, Freeman KS, Charles J, Ammar DA, Ehrhart EJ. Pilot study supporting the existence of novel lymphatic channels within the canine anterior uveal tract using Lyve-1 and CD31. Vet Ophthalmol 2021; 24:354-360. [PMID: 33977630 DOI: 10.1111/vop.12893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 04/03/2021] [Accepted: 04/05/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To demonstrate the existence of lymphatics in the canine anterior uvea using lymphatic-specific markers Lyve-1, Prox-1, and podoplanin, the endothelial cell marker CD31, and basement membrane matrix marker collagen IV. DESIGN Prospective Study. ANIMALS Eight normal globes from animals euthanized for unrelated health problems. PROCEDURES Sagittally cut serial sections of six normal canine eyes were immunofluorescence double-stained with Lyve-1 and CD31 and single-stained with colorimetric Prox-1 and collagen IV. Three serial sections from 2 additional eyes were cut in the coronal plane at the level of the ciliary body and immunofluorescence double-stained with Lyve-1 and CD31 to map lymphatic channel distribution. Lymphatics from normal canine lymph nodes were used for validation of podoplanin. RESULTS Four of 6 of the sagitally sectioned eyes had Lyve-1-positive lymphatic-like structures that were distinct from CD31-positive blood vessels in the iris base and ciliary body. Both of the coronally sectioned globes had Lyve-1-positive lymphatic-like structures in the ciliary body. The location of these structures was evaluated and found to be diffusely present circumferentially around the ciliary body. CONCLUSION AND CLINICAL RELEVANCE These results support the existence of lymphatic channels in the anterior uveal tract of the canine eye. This could indicate the presence of a novel uveolymphatic outflow pathway, which may play a role in aqueous humor outflow. Future studies are needed to confirm the existence and elucidate the role of this proposed uveolymphatic outflow pathway and potentially develop novel treatment options for managing glaucoma.
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Affiliation(s)
- Alexis Dubin
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Kate S Freeman
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Joseph Charles
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - David A Ammar
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Eugene J Ehrhart
- Ethos Discovery, San Diego, CA, USA.,Ethos Veterinary Health, Woburn, MA, USA
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7
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Nur İH, Saçmacı Ş, Orhan İ, Perez W, Testereci H. Morphological analysis of aqueous humor drainage using QD nanoparticles and indocyanine green. Microsc Res Tech 2020; 83:1032-1044. [PMID: 32445617 DOI: 10.1002/jemt.23494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/07/2020] [Accepted: 03/28/2020] [Indexed: 11/06/2022]
Abstract
This study represents the first morphological description of the lymphatic drainage of the ciliary body in vivo by comparative hyperspectral fluorescence imaging techniques of Quantum Qdot655 (QD) nanoparticles and indocyanine green (ICG). A volume of 1.25 μl of QD was injected into the left anterior camera of all rats. Similarly,1.25 μl of ICG diluted at a ratio of one-fourth with physiological saline solution was injected into the right anterior camera of all rats. The thickness of the skin in the mandibular area, connective tissue, and the depth of the mandibular lymph node (MLN) made image retrieval difficult. For QD, 302 nm UV excitation and 605 nm fluorescence peak emission were applied. The detection of QD and ICG used in this study in the MLNs is definitive evidence that aqueous humor (AH) follows a uveolymphatic pathway. Scanning electron microscope and the energy dispersive X-ray analyzer spectrum were used to examine both the Schlemm's canal and the MLN. For the first time, the QD was detected in the cortex of MLN. The QCM analysis of both QD-AH and ICG-AH was used to determine whether there was any interaction between them. This comparative study shows the importance of experimental animal modeling in pharmacological studies regarding eye research and drugs. In a female rat, the signal was taken from the parotid lymph node with QD injections.
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Affiliation(s)
- İsmail Hakkı Nur
- Department of Anatomy, Faculty of Veterinary Medicine, Erciyes University, Kayseri, Turkey
| | - Şerife Saçmacı
- Department of Chemistry, Science Faculty, Erciyes University, Kayseri, Turkey
| | - İmdat Orhan
- Department of Anatomy, Faculty of Veterinary Medicine, Erciyes University, Kayseri, Turkey
| | - William Perez
- Área de Anatomía, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay
| | - Haluk Testereci
- Department of Medical Biochemistry, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey
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8
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Yücel YH, Cheng F, Cardinell K, Zhou X, Irving H, Gupta N. Age-related decline of lymphatic drainage from the eye: A noninvasive in vivo photoacoustic tomography study. Exp Eye Res 2020; 194:108029. [PMID: 32251650 DOI: 10.1016/j.exer.2020.108029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/11/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023]
Abstract
We aim to determine whether lymphatic drainage from the eye changes with age. Using quantitative photoacoustic tomography, groups of young and older mice were studied in the live state. 10 CD-1 mice of 2-3 months (5M/5F) were studied in addition to 13 older mice of 12-13 months (6M/7F). In each of 23 mice, near-infrared tracer (a near-infrared dye, QC-1 conjugated with Bovine Serum Albumin) was injected into the right eye, and imaging of ipsilateral cervical lymph nodes was performed with laser pulses at 11 different wavelengths prior to and 20 min, 2, 4 and 6 h after injection. Mean pixel intensities (MPIs) of nodes were calculated at each imaging session. The areas under the curves (AUC) were calculated for both groups of mice and compared using the t-test. The slopes of MPI of each region of interest were compared using the linear mixed model before and after adjusting for sex, body weight and intraocular pressure of the right eye. The mean intraocular pressure of right eyes before injection was similar in older and younger groups (12.77 ± 2.01 mmHg and 12.90 ± 2.38 mmHg, respectively; p = 0.888). In each mouse, the photoacoustic signal was detected in the right cervical lymph nodes at the 2-h time point following tracer injection into the right eye. At the 4 and 6 h imaging times, a steady increase of tracer signal was observed. Areas under the curve in the right cervical nodes were decreased significantly in older mice compared to younger mice (p = 0.007). The slopes of MPI in the nodes were significantly decreased in old mice compared to young mice both before and after adjusting for sex, body weight and intraocular pressure of the right eye (p = 0.003). In conclusion, lymphatic drainage from the eye is significantly reduced in older eyes. This finding suggests that impaired lymphatic clearance of aqueous humor, proteins and antigens from the eye may contribute to age-related disease of the eye such as glaucoma and inflammatory eye disease.
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Affiliation(s)
- Yeni H Yücel
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine & Pathobiology, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Ophthalmic Pathology Laboratory, University of Toronto, Toronto, Ontario, Canada; Department of Physics, Faculty of Science, Ryerson University, Toronto, Ontario, Canada; Institute of Biomedical Engineering, Science and Technology (iBEST), St. Michael's Hospital, Ryerson University, Toronto, Ontario, Canada; Department of Mechanical Engineering, Faculty of Engineering and Architectural Science, Ryerson University, Toronto, Ontario, Canada.
| | - Fang Cheng
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Ophthalmology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Kirsten Cardinell
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Physics, Faculty of Science, Ryerson University, Toronto, Ontario, Canada
| | - Xun Zhou
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Hyacinth Irving
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Neeru Gupta
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine & Pathobiology, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
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Deng W, Liu C, Parra C, Sims JR, Faiq MA, Sainulabdeen A, Song H, Chan KC. Quantitative imaging of the clearance systems in the eye and the brain. Quant Imaging Med Surg 2020; 10:1-14. [PMID: 31956524 DOI: 10.21037/qims.2019.11.18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Wenyu Deng
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA
| | - Crystal Liu
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA
| | - Carlos Parra
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA
| | - Jeffrey R Sims
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA
| | - Muneeb A Faiq
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA
| | - Anoop Sainulabdeen
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA
| | - Hana Song
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA
| | - Kevin C Chan
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA.,Department of Radiology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA.,Neuroscience Institute, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, USA.,Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, USA
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10
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How many aqueous humor outflow pathways are there? Surv Ophthalmol 2019; 65:144-170. [PMID: 31622628 DOI: 10.1016/j.survophthal.2019.10.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 09/29/2019] [Accepted: 10/04/2019] [Indexed: 12/31/2022]
Abstract
The aqueous humor (AH) outflow pathways definition is still matter of intense debate. To date, the differentiation between conventional (trabecular meshwork) and unconventional (uveoscleral) pathways is widely accepted, distinguishing the different impact of the intraocular pressure on the AH outflow rate. Although the conventional route is recognized to host the main sites for intraocular pressure regulation, the unconventional pathway, with its great potential for AH resorption, seems to act as a sort of relief valve, especially when the trabecular resistance rises. Recent evidence demonstrates the presence of lymphatic channels in the eye and proposes that they may participate in the overall AH drainage and intraocular pressure regulation, in a presumably adaptive fashion. For this reason, the uveolymphatic route is increasingly thought to play an important role in the ocular hydrodynamic system physiology. As a result of the unconventional pathway characteristics, hydrodynamic disorders do not develop until the adaptive routes cannot successfully counterbalance the increased AH outflow resistance. When their adaptive mechanisms fail, glaucoma occurs. Our review deals with the standard and newly discovered AH outflow routes, with particular attention to the importance they may have in opening new therapeutic strategies in the treatment of ocular hypertension and glaucoma.
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11
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Yücel YH, Cardinell K, Khattak S, Zhou X, Lapinski M, Cheng F, Gupta N. Active Lymphatic Drainage From the Eye Measured by Noninvasive Photoacoustic Imaging of Near-Infrared Nanoparticles. Invest Ophthalmol Vis Sci 2019; 59:2699-2707. [PMID: 29860456 DOI: 10.1167/iovs.17-22850] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To visualize and quantify lymphatic drainage of aqueous humor from the eye to cervical lymph nodes in the dynamic state. Methods A near-infrared tracer was injected into the right eye anterior chamber of 10 mice under general anesthesia. Mice were imaged with photoacoustic tomography before and 20 minutes, 2, 4, and 6 hours after injection. Tracer signal intensity was measured in both eyes and right and left neck lymph nodes at every time point and signal intensity slopes were calculated. Slope differences between right and left eyes and right and left nodes were compared using paired t-test. Neck nodes were examined with fluorescence optical imaging and histologically for the presence of tracer. Results Following right eye intracameral injection of tracer, an exponential decrease in tracer signal was observed from 20 minutes to 6 hours in all mice. Slope differences of the signal intensity between right and left eyes were significant (P < 0.001). Simultaneously, increasing tracer signal was observed in the right neck node from 20 minutes to 6 hours. Slope differences of the signal intensity between right and left neck nodes were significant (P = 0.0051). Ex vivo optical fluorescence imaging and histopathologic examination of neck nodes confirmed tracer presence within submandibular nodes. Conclusions Active lymphatic drainage of aqueous from the eye to cervical lymph nodes was measured noninvasively by photoacoustic imaging of near-infrared nanoparticles. This unique in vivo assay may help to uncover novel drugs that target alternative outflow routes to lower IOP in glaucoma and may provide new insights into lymphatic drainage in eye health and disease.
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Affiliation(s)
- Yeni H Yücel
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine & Pathobiology, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Physics, Faculty of Science, Ryerson University, Toronto, Ontario, Canada.,Institute of Biomedical Engineering, Science and Technology (iBEST), St. Michael's Hospital, Ryerson University, Toronto, Ontario, Canada.,Department of Mechanical Engineering, Faculty of Engineering and Architectural Science, Ryerson University, Toronto, Ontario, Canada
| | - Kirsten Cardinell
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Physics, Faculty of Science, Ryerson University, Toronto, Ontario, Canada
| | - Shireen Khattak
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine & Pathobiology, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Xun Zhou
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Michael Lapinski
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Fang Cheng
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Neeru Gupta
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine & Pathobiology, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Glaucoma Unit, St. Michael's Hospital, Toronto, Ontario, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
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12
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Kasper M, Gabriel D, Möller M, Bauer D, Wildschütz L, Courthion H, Rodriguez-Aller M, Busch M, Böhm MRR, Loser K, Thanos S, Gurny R, Heiligenhaus A. Cyclosporine A-Loaded Nanocarriers for Topical Treatment of Murine Experimental Autoimmune Uveoretinitis. Mol Pharm 2018; 15:2539-2547. [PMID: 29912566 DOI: 10.1021/acs.molpharmaceut.8b00014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study, tissue distribution and the therapeutic effect of topically applied cyclosporine A (CsA)-loaded methoxy-poly(ethylene-glycol)-hexyl substituted poly(lactic acid) (mPEGhexPLA) nanocarriers (ApidSOL) on experimental autoimmune uveitis (EAU) were investigated. The CsA-loaded mPEGhexPLA nanocarrier was tolerated well locally and showed no signs of immediate toxicity after repeated topical application in mice with EAU. Upon unilateral CsA treatment, CsA accumulated predominantly in the corneal and sclera-choroidal tissue of the treated eye and in lymph nodes (LN). This regimen reduced EAU severity in treated eyes compared to PBS-treated controls. This improvement was accompanied by reduced T-cell count, T-cell proliferation, and IL-2 secretion of cells from ipsilateral LN. In conclusion, topical treatment with CsA-loaded mPEGhexPLA nanocarriers significantly improves the outcome of EAU.
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Affiliation(s)
- Maren Kasper
- Department of Ophthalmology and Ophtha-Lab , St. Franziskus Hospital , Münster 48145 , Germany
| | | | - Michael Möller
- School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva 1221 , Switzerland
| | - Dirk Bauer
- Department of Ophthalmology and Ophtha-Lab , St. Franziskus Hospital , Münster 48145 , Germany
| | - Lena Wildschütz
- Department of Ophthalmology and Ophtha-Lab , St. Franziskus Hospital , Münster 48145 , Germany
| | | | - Marta Rodriguez-Aller
- School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva 1221 , Switzerland
| | - Martin Busch
- Department of Ophthalmology and Ophtha-Lab , St. Franziskus Hospital , Münster 48145 , Germany
| | - Michael R R Böhm
- Department of Ophthalmology, Clinic for Diseases of the Anterior Segments of the Eyes , Essen University Hospital , Essen 45147 , Germany
| | | | | | - Robert Gurny
- Apidel SA , Geneva 1201 , Switzerland.,School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva 1221 , Switzerland
| | - Arnd Heiligenhaus
- Department of Ophthalmology and Ophtha-Lab , St. Franziskus Hospital , Münster 48145 , Germany.,University of Duisburg-Essen , Essen 47057 , Germany
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13
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Tomczyk-Socha M, Turno-Kręcicka A. A Novel Uveolymphatic Drainage Pathway-Possible New Target for Glaucoma Treatment. Lymphat Res Biol 2017; 15:360-363. [PMID: 29077522 DOI: 10.1089/lrb.2017.0019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Glaucoma is a heterogeneous group of ophthalmic diseases leading to irreversible damage to the optic nerve. While the overall mechanism responsible for glaucoma remains obscure, the most important risk factor is elevated intraocular pressure. The current therapies, whether pharmacological or surgical, are primarily symptomatic with the aim to lower the intraocular pressure (IOP). Poorer response to treatment is associated, for example, with pseudoexfoliation glaucoma, which is determined by blocking the trabecular meshwork (TM) both by pigment grains and the pseudoexfoliation material. It was thought that aqueous humor is drained from the eye by two main pathways: conventional outflow through the TM and Schlemm's canal; and unconventional outflow through the ciliary body through uveal tissue. In 2009 Yucel et al. described and proved the presence of a third pathway for aqueous humor drainage using two specific lymphatic markers: podoplanin, and lymphatic vessel endothelial hyaluronan receptor-1 to identify lymphatic channels in the human ciliary body. The discovery identifies a novel target for IOP-lowering therapies. The most promising group are prostaglandins, which are widely prescribed for glaucoma patients. An intriguing new possibility in glaucoma therapy is using ANGPT agonist. It is still not known if the lymphatic drainage in glaucoma is decreased or dysfunctional and whether lymphatic stimulation can help in removing the improperly accumulated substances, as is seen in pseudoexfoliation glaucoma. However, this new target for glaucoma treatment appears very promising.
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14
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Abstract
The choroid is part of the uveal tract and is a heavily vascularized bed that also contains connective tissue and melanin pigment. Given the role of the choroidal vasculature in the blood supply of the anterior laminar and prelaminar regions of the optic nerve head, the peripapillary choroid might be a relevant target for investigation in patients with glaucoma. The purpose of this paper is to critically review the current understanding of potential role of the choroid in the pathogenesis of glaucomatous damage.
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15
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Johnson M, McLaren JW, Overby DR. Unconventional aqueous humor outflow: A review. Exp Eye Res 2017; 158:94-111. [PMID: 26850315 PMCID: PMC4970980 DOI: 10.1016/j.exer.2016.01.017] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 01/04/2016] [Accepted: 01/26/2016] [Indexed: 11/17/2022]
Abstract
Aqueous humor flows out of the eye primarily through the conventional outflow pathway that includes the trabecular meshwork and Schlemm's canal. However, a fraction of aqueous humor passes through an alternative or 'unconventional' route that includes the ciliary muscle, supraciliary and suprachoroidal spaces. From there, unconventional outflow may drain through two pathways: a uveoscleral pathway where aqueous drains across the sclera to be resorbed by orbital vessels, and a uveovortex pathway where aqueous humor enters the choroid to drain through the vortex veins. We review the anatomy, physiology and pharmacology of these pathways. We also discuss methods to determine unconventional outflow rate, including direct techniques that use radioactive or fluorescent tracers recovered from tissues in the unconventional pathway and indirect methods that estimate unconventional outflow based on total outflow over a range of pressures. Indirect methods are subject to a number of assumptions and generally give poor agreement with tracer measurements. We review the variety of animal models that have been used to study conventional and unconventional outflow. The mouse appears to be a promising model because it captures several aspects of conventional and unconventional outflow dynamics common to humans, although questions remain regarding the magnitude of unconventional outflow in mice. Finally, we review future directions. There is a clear need to develop improved methods for measuring unconventional outflow in both animals and humans.
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Affiliation(s)
- Mark Johnson
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA; Department of Ophthalmology, Northwestern University, Chicago, IL, USA.
| | - Jay W McLaren
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, England, UK
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16
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Wostyn P, Killer HE, De Deyn PP. Glymphatic stasis at the site of the lamina cribrosa as a potential mechanism underlying open-angle glaucoma. Clin Exp Ophthalmol 2017; 45:539-547. [PMID: 28129671 DOI: 10.1111/ceo.12915] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 12/08/2016] [Accepted: 01/04/2017] [Indexed: 12/31/2022]
Abstract
The underlying pathophysiology of primary open-angle glaucoma remains unclear, but the lamina cribrosa seems to be the primary site of injury, and raised intraocular pressure is a major risk factor. In recent years, a decreased intracranial pressure, leading to an abnormally high trans-lamina cribrosa pressure difference, has gained interest as a new risk factor for glaucoma. New research now lends support to the hypothesis that a paravascular transport system is present in the eye analogous to the recently discovered 'glymphatic system' in the brain, which is a functional waste clearance pathway that promotes elimination of interstitial solutes, including β-amyloid, from the brain along paravascular channels. Given that β-amyloid has been reported to increase by chronic elevation of intraocular pressure in glaucomatous animal models and to cause retinal ganglion cell death, the discovery of a paravascular clearance system in the eye may provide powerful new insights into the pathophysiology of primary open-angle glaucoma. In this review, we provide a new conceptual framework for understanding the pathogenesis of primary open-angle glaucoma, present supporting preliminary data from our own post-mortem study and hypothesize that the disease may result from restriction of normal glymphatic flow at the level of the lamina cribrosa owing to a low intracranial pressure and/or a high trans-lamina cribrosa pressure gradient. If confirmed, this viewpoint could offer new perspectives for the development of novel diagnostic and therapeutic strategies for this devastating disorder.
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Affiliation(s)
- Peter Wostyn
- Department of Psychiatry, PC Sint-Amandus, Beernem, Belgium
| | | | - Peter Paul De Deyn
- Laboratory of Neurochemistry and Behavior. Institute Born-Bunge, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Department of Neurology and Memory Clinic, Middelheim General Hospital (ZNA), Antwerp, Belgium.,Department of Neurology and Alzheimer Research Center, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
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17
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Yucel Y, Gupta N. Lymphatic drainage from the eye: A new target for therapy. PROGRESS IN BRAIN RESEARCH 2015; 220:185-98. [PMID: 26497791 DOI: 10.1016/bs.pbr.2015.07.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lowering intraocular pressure (IOP) has been central to glaucoma care for over a century. In order to prevent sight loss from disease, there has been considerable focus on medical and surgical methods to improve fluid drainage from the eye. In spite of this, our understanding of exactly how aqueous humor leaves the eye is not complete. Recently, lymphatic vessels have been discovered in the human uvea, with studies showing lymphatic fluid outflow in several models, in addition to evidence for their pharmacological enhancement. The presence of a lymphatic outflow system points to an exciting, expanded understanding of how fluid and particulate materials such as proteins move out of the eye, and how IOP may be regulated. We coin the term "uveolymphatic pathway"-to reflect a comprehensive and compelling new target for glaucoma and an exciting opportunity for future investigations to better understand the eye in health and disease.
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Affiliation(s)
- Yeni Yucel
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada; Ophthalmic Pathology Laboratory, University of Toronto, St. Michael's Hospital, Toronto, ON, Canada; Faculty of Engineering & Architectural Science, Ryerson University, Toronto, ON, Canada.
| | - Neeru Gupta
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada; Glaucoma and Nerve Protection Unit, St. Michael's Hospital, Toronto, ON, Canada
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18
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Rasmussen CA, Kaufman PL. Exciting directions in glaucoma. Can J Ophthalmol 2015; 49:534-43. [PMID: 25433744 DOI: 10.1016/j.jcjo.2014.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/13/2014] [Indexed: 01/15/2023]
Abstract
Glaucoma is a complex, life-long disease that requires an individualized, multifaceted approach to treatment. Most patients will be started on topical ocular hypotensive eyedrop therapy, and over time multiple classes of drugs will be needed to control their intraocular pressure. The search for drugs with novel mechanisms of action, to treat those who do not achieve adequate intraocular pressure control with, or become refractory to, current therapeutics, is ongoing, as is the search for more efficient, targeted drug delivery methods. Gene-transfer and stem-cell applications for glaucoma therapeutics are moving forward. Advances in imaging technologies improve our understanding of glaucoma pathophysiology and enable more refined patient evaluation and monitoring, improving patient outcomes.
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Affiliation(s)
- Carol A Rasmussen
- Department of Ophthalmology & Visual Sciences, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA..
| | - Paul L Kaufman
- Department of Ophthalmology & Visual Sciences, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA
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19
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Schmidl D, Schmetterer L, Garhöfer G, Popa-Cherecheanu A. Pharmacotherapy of glaucoma. J Ocul Pharmacol Ther 2015; 31:63-77. [PMID: 25587905 PMCID: PMC4346603 DOI: 10.1089/jop.2014.0067] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 10/31/2014] [Indexed: 12/25/2022] Open
Abstract
Glaucoma is a group of diseases involving the optic nerve and associated structures, which is characterized by progressive visual field loss and typical changes of the optic nerve head (ONH). The only known treatment of the disease is reduction of intraocular pressure (IOP), which has been shown to reduce glaucoma progression in a variety of large-scale clinical trials. Nowadays, a relatively wide array of topical antiglaucoma drugs is available, including prostaglandin analogues, carbonic anhydrase inhibitors, beta-receptor antagonists, adrenergic agonists, and parasympathomimetics. In clinical routine, this allows for individualized treatment taking risk factors, efficacy, and safety into account. A major challenge is related to adherence to therapy. Sustained release devices may help minimize this problem but are not yet available for clinical routine use. Another hope arises from non-IOP-related treatment concepts. In recent years, much knowledge has been gained regarding the molecular mechanisms that underlie the disease process in glaucoma. This also strengthens the hope that glaucoma therapy beyond IOP lowering will become available. Implementing this concept with clinical trials remains, however, a challenge.
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Affiliation(s)
- 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
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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20
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Thomson BR, Heinen S, Jeansson M, Ghosh AK, Fatima A, Sung HK, Onay T, Chen H, Yamaguchi S, Economides AN, Flenniken A, Gale NW, Hong YK, Fawzi A, Liu X, Kume T, Quaggin SE. A lymphatic defect causes ocular hypertension and glaucoma in mice. J Clin Invest 2014; 124:4320-4. [PMID: 25202984 DOI: 10.1172/jci77162] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/31/2014] [Indexed: 01/11/2023] Open
Abstract
Glaucoma is a leading cause of blindness, afflicting more than 60 million people worldwide. Increased intraocular pressure (IOP) due to impaired aqueous humor drainage is a major risk factor for the development of glaucoma. Here, we demonstrated that genetic disruption of the angiopoietin/TIE2 (ANGPT/TIE2) signaling pathway results in high IOP, buphthalmos, and classic features of glaucoma, including retinal ganglion degeneration and vision loss. Eyes from mice with induced deletion of Angpt1 and Angpt2 (A1A2Flox(WB) mice) lacked drainage pathways in the corneal limbus, including Schlemm's canal and lymphatic capillaries, which share expression of the PROX1, VEGFR3, and FOXC family of transcription factors. VEGFR3 and FOXCs have been linked to lymphatic disorders in patients, and FOXC1 has been linked to glaucoma. In contrast to blood endothelium, in which ANGPT2 is an antagonist of ANGPT1, we have shown that both ligands cooperate to regulate TIE2 in the lymphatic network of the eye. While A1A2Flox(WB) mice developed high IOP and glaucoma, expression of ANGPT1 or ANGPT2 alone was sufficient for ocular drainage. Furthermore, we demonstrated that loss of FOXC2 from lymphatics results in TIE2 downregulation, suggesting a mechanism for ocular defects in patients with FOXC mutations. These data reveal a pathogenetic and molecular basis for glaucoma and demonstrate the importance of angiopoietin ligand cooperation in the lymphatic endothelium.
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21
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Lee ES, Rasmussen CA, Filla MS, Slauson SR, Kolb AW, Peters DM, Kaufman PL, Gabelt BT, Brandt CR. Prospects for lentiviral vector mediated prostaglandin F synthase gene delivery in monkey eyes in vivo. Curr Eye Res 2014; 39:859-70. [PMID: 24559478 DOI: 10.3109/02713683.2014.884593] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Currently, the most effective outflow drugs approved for clinical use are prostaglandin F2α analogues, but these require daily topical self-dosing and have various intraocular, ocular surface and extraocular side effects. Lentiviral vector-mediated delivery of the prostaglandin F synthase (PGFS) gene, resulting in long-term reduction of intraocular pressure (IOP), may eliminate off-target tissue effects and the need for daily topical PGF2α self-administration. Lentiviral vector-mediated delivery of the PGFS gene to the anterior segment has been achieved in cats and non-human primates. Although these results are encouraging, our studies have identified a number of challenges that need to be overcome for prostaglandin gene therapy to be translated into the clinic. Using examples from our work in non-human primates, where we were able to achieve a significant reduction in IOP (2 mm Hg) for 5 months after delivery of the cDNA for bovine PGF synthase, we identify and discuss these issues and consider several possible solutions.
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Affiliation(s)
- Eun Suk Lee
- Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine , Seoul , Korea
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22
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Wiggans KT, Skorupski KA, Reilly CM, Frazier SA, Dubielzig RR, Maggs DJ. Presumed solitary intraocular or conjunctival lymphoma in dogs and cats: 9 cases (1985–2013). J Am Vet Med Assoc 2014; 244:460-70. [DOI: 10.2460/javma.244.4.460] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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Yucel YH, Gupta N, Kagan DB, Khan AM, Navajas EV, Jin YP. Author reply: To PMID 23062649. Ophthalmology 2013; 120:e42-3. [PMID: 23823515 DOI: 10.1016/j.ophtha.2013.03.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 03/27/2013] [Indexed: 10/26/2022] Open
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24
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Tam ALC, Gupta N, Zhang Z, Yücel YH. Latanoprost Stimulates Ocular Lymphatic Drainage: An In Vivo Nanotracer Study. Transl Vis Sci Technol 2013; 2:3. [PMID: 24049723 DOI: 10.1167/tvst.2.5.3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Accepted: 05/31/2013] [Indexed: 10/26/2022] Open
Abstract
PURPOSE Ocular lymphatics have been recently shown to contribute to aqueous humor outflow. It is not yet known whether lymphatic outflow can be stimulated by pharmacological agents. Here we determine whether latanoprost, a prostaglandin F2 alpha analog commonly used to lower IOP to treat glaucoma, increases lymphatic drainage from the eye. METHODS Lymphatic drainage in mice was assessed in vivo, in 11 latanoprost-treated and 11 control animals using hyperspectral imaging at multiple times following quantum dot (QD) injection into the eye. QD signal intensity was also measured in tissue sections using hyperspectral imaging. RESULTS In the latanoprost-treated group, lymphatic drainage rate into the submandibular lymph node was increased compared with controls (1.23 ± 1.06 hours-1 vs. 0.30 ± 0.17 hours-1, mean ± SD, P < 0.02). Total QD signal intensity in the submandibular lymph node was greater in the latanoprost-treated group compared with controls (10.55 ± 1.12 vs. 9.48 ± 1.24, log scale, P < 0.05). CONCLUSIONS This is the first evidence that latanoprost increases lymphatic drainage from the eye. The pharmacological manipulation of this newly identified lymphatic outflow pathway may be relevant to treatments aimed at lowering intraocular pressure in glaucoma. TRANSLATIONAL RELEVANCE This is the first evidence that a prostaglandin drug widely prescribed for glaucoma, enhances lymphatic drainage from the eye. The pharmacological stimulation of this newly identified outflow pathway may be highly relevant to treatments aimed at lowering IOP to prevent blindness from glaucoma.
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Affiliation(s)
- Alex L C Tam
- Department of Ophthalmology and Vision Sciences, University of Toronto, Canada ; Keenan Research Centre at the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
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25
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Tezel G. Immune regulation toward immunomodulation for neuroprotection in glaucoma. Curr Opin Pharmacol 2012; 13:23-31. [PMID: 23084793 DOI: 10.1016/j.coph.2012.09.013] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 09/19/2012] [Accepted: 09/21/2012] [Indexed: 01/04/2023]
Abstract
Although the immune system functions to preserve and restore tissue homeostasis, accumulating risk factors, prolonged glial activation, and sustained release of pro-inflammatory mediators in glaucoma may lead to a failure in the regulation of stress-induced immune response, and innate immune cells, autoreactive T cells, autoantibodies, and excess complement attack may exhibit potent stimuli that harm retinal ganglion cell somas, axons, and synapses. Identification of the cellular and molecular components of immune response pathways can provide immunomodulatory treatment strategies to attenuate neuroinflammation, protect neural tissue from collateral injury, and enhance endogenous recovery processes. This review highlights the current knowledge of molecular mechanisms regulating neuroinflammation in glaucoma.
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Affiliation(s)
- Gülgün Tezel
- Departments of Ophthalmology & Visual Sciences and Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, KY, USA.
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