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Strohmaier CA, Wanderer D, Zhang X, Zhang HF, Strohmaier S, Weinreb RN, Huang AS. Lack of Correlation Between Segmental Trabecular Meshwork Pigmentation and Angiographically Determined Outflow in Ex Vivo Human Eyes. J Glaucoma 2024; 33:355-360. [PMID: 37851964 PMCID: PMC10995104 DOI: 10.1097/ijg.0000000000002318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/18/2023] [Indexed: 10/20/2023]
Abstract
PRCIS Trabecular meshwork (TM) pigmentation is not correlated with angiographically determined aqueous humor outflow (AHO) in an ex vivo perfusion model using human eyes. PURPOSE To evaluate whether segmental TM pigmentation is correlated to segmental AHO in human eyes. METHODS Postmortem human eyes were acquired, and anterior segments were dissected. TM pigmentation was photographed 360-degrees around the eye. The anterior segments were then mounted onto a perfusion apparatus and perfused with Dulbecco's phosphate buffered saline (DPBS) until a stabile baseline outflow facility was achieved. Aqueous angiography (AHO angiography) was performed using fluorescein (2%), and segmental AHO was documented around the limbus using an angiographic camera (Spectralis HRA+OCT). Circumferential and nasal TM pigmentation were compared with respective angiographic outflow imaging using a Pearson correlation analysis. RESULTS Segmental TM pigment distribution and segmental AHO were seen. TM pigment was statistically greatest in the inferior quadrant. AHO angiographic outflow was numerically greatest in the nasal quadrant, but this was not statistically significant. No statistically significant correlation was observed (r=-0.083, P =0.06) between segmental TM pigmentation and segmental AHO angiographic signal. Analyzing just the nasal quadrant, a significant weak negative correlation was found (r=-0.296, P =0.001). DISCUSSION Segmental TM pigmentation circumferentially around the eye is not a good proxy for segmental AHO circumferentially around the eye and should not be used to guide trabecular minimally invasive glaucoma surgeries.
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Affiliation(s)
- Clemens A. Strohmaier
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
- Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austria
| | - Daniel Wanderer
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
| | - Xiaowei Zhang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Susanne Strohmaier
- Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria
| | - Robert N. Weinreb
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
| | - Alex S. Huang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, CA, USA
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Faralli JA, Filla MS, Yang YF, Sun YY, Johns K, Keller KE, Peters DM. Digital spatial profiling of segmental outflow regions in trabecular meshwork reveals a role for ADAM15. PLoS One 2024; 19:e0298802. [PMID: 38394161 PMCID: PMC10889904 DOI: 10.1371/journal.pone.0298802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
In this study we used a spatial transcriptomics approach to identify genes specifically associated with either high or low outflow regions in the trabecular meshwork (TM) that could potentially affect aqueous humor outflow in vivo. High and low outflow regions were identified and isolated from organ cultured human anterior segments perfused with fluorescently-labeled 200 nm FluoSpheres. The NanoString GeoMx Digital Spatial Profiler (DSP) platform was then used to identified genes in the paraffin embedded tissue sections from within those regions. These transcriptome analyses revealed that 16 genes were statistically upregulated in high outflow regions and 57 genes were statistically downregulated in high outflow regions when compared to low outflow regions. Gene ontology enrichment analysis indicated that the top three biological categories of these differentially expressed genes were ECM/cell adhesion, signal transduction, and transcription. The ECM/cell adhesion genes that showed the largest differential expression (Log2FC ±1.5) were ADAM15, BGN, LDB3, and CRKL. ADAM15, which is a metalloproteinase that can bind integrins, was upregulated in high outflow regions, while the proteoglycan BGN and two genes associated with integrin signaling (LDB3, and CRKL) were downregulated. Immunolabeling studies supported the differential expression of ADAM15 and showed that it was specifically upregulated in high outflow regions along the inner wall of Schlemm's canal and in the juxtacanalicular (JCT) region of the TM. In addition to these genes, the studies showed that genes for decorin, a small leucine-rich proteoglycan, and the α8 integrin subunit were enriched in high outflow regions. These studies identify several novel genes that could be involved in segmental outflow, thus demonstrating that digital spatial profiling could be a useful approach for understanding segmental flow through the TM. Furthermore, this study suggests that changes in the expression of genes involved in regulating the activity and/or organization of the ECM and integrins in the TM are likely to be key players in segmental outflow.
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Affiliation(s)
- Jennifer A. Faralli
- Departments of Pathology & Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Mark S. Filla
- Departments of Pathology & Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Yong-Feng Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Ying Ying Sun
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Kassidy Johns
- Departments of Pathology & Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Kate E. Keller
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Donna M. Peters
- Departments of Pathology & Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
- Ophthalmology & Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States of America
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Strohmaier CA, Wanderer D, Zhang X, Agarwal D, Toomey CB, Wahlin K, Zhang HF, Stamer WD, Weinreb RN, McDonnell FS, Huang AS. Greater Outflow Facility Increase After Targeted Trabecular Bypass in Angiographically Determined Low-low Regions. Ophthalmol Glaucoma 2023; 6:570-579. [PMID: 37348815 PMCID: PMC10917462 DOI: 10.1016/j.ogla.2023.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/31/2023] [Accepted: 06/14/2023] [Indexed: 06/24/2023]
Abstract
PURPOSE To investigate the impact of trabecular bypass surgery targeted to angiographically determined high- vs. low-aqueous humor outflow areas on outflow facility (C) and intraocular pressure (IOP). DESIGN Ex vivo comparative study. SUBJECTS Postmortem ex vivo porcine and human eyes. METHODS Porcine (n = 14) and human (n = 13) whole globes were acquired. In both species, anterior segments were dissected, mounted onto a perfusion chamber, and perfused using Dulbecco's phosphate buffered solution containing glucose in a constant flow paradigm to achieve a stable baseline. Fluorescein was perfused into the anterior chamber and used to identify baseline segmental high- and low-flow regions of the conventional outflow pathways. The anterior segments were divided into 2 groups, and a 5 mm needle goniotomy was performed in either a high- or low-flow area. Subsequently, C and IOP were quantitatively reassessed and compared between surgery in baseline "high-flow" and "low-flow" region eyes followed by indocyanine green angiography. MAIN OUTCOME MEASURES Outflow facility. RESULTS In all eyes, high- and low-flow segments could be identified. Performing a 5-mm goniotomy increased outflow facility to a variable extent depending on baseline flow status. In the porcine high-flow group, C increased from 0.31 ± 0.09 to 0.39 ± 0.09 μL/mmHg/min (P = 0.12). In the porcine low-flow group, C increased from 0.29 ± 0.03 to 0.56 ± 0.10 μL/mmHg/min (P < 0.001). In the human high-flow group, C increased from 0.38 ± 0.20 to 0.41 ± 0.20 μL/mmHg/min (P = 0.02). In the human low-flow group, C increased from 0.25 ± 0.11 to 0.32 ± 0.11 μL/mmHg/min (<0.001). There was statistically significant greater increase in C for eyes where surgery was targeted to baseline low-flow regions in both porcine (0.07 ± 0.09 vs. 0.27 ± 0.13, P = 0.007 μL/mmHg/min, high vs low flow) and human eyes (0.03 ± 0.03 vs. 0.07 ± 0.02, P = 0.03 μL/mmHg/min, high vs. low flow). CONCLUSIONS Targeting surgery to low-flow areas of the trabecular meshwork yields higher overall facility increase and IOP reduction compared to surgery in high-flow areas. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Clemens A Strohmaier
- Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austria; The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California.
| | - Daniel Wanderer
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Xiaowei Zhang
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Devansh Agarwal
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Christopher B Toomey
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Karl Wahlin
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - W Daniel Stamer
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Robert N Weinreb
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
| | | | - Alex S Huang
- The Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California
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Strohmaier CA, McDonnell FS, Zhang X, Wanderer D, Stamer WD, Weinreb RN, Huang AS. Differences in Outflow Facility Between Angiographically Identified High- Versus Low-Flow Regions of the Conventional Outflow Pathways in Porcine Eyes. Invest Ophthalmol Vis Sci 2023; 64:29. [PMID: 36939719 PMCID: PMC10043501 DOI: 10.1167/iovs.64.3.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023] Open
Abstract
Purpose To investigate differences in outflow facility between angiographically determined high- and low-flow segments of the conventional outflow pathway in porcine eyes. Methods Porcine anterior segments (n = 14) were mounted in a perfusion chamber and perfused using Dulbecco's phosphate buffered solution with glucose. Fluorescein angiography was performed to determine high- and low-flow regions of the conventional outflow pathways. The trabecular meshwork (TM) was occluded using cyanoacrylate glue, except for residual 5-mm TM areas that were either high or low flow at baseline, designating these eyes as "residual high-flow" or "residual low-flow" eyes. Subsequently, outflow was quantitatively reassessed and compared between residual high-flow and residual low-flow eyes followed by indocyanine green angiography. Results Fluorescein aqueous angiography demonstrated high-flow and low-flow regions. Baseline outflow facilities were 0.320 ± 0.08 and 0.328 ± 0.10 µL/min/mmHg (P = 0.676) in residual high-flow and residual low-flow eyes before TM occlusion, respectively. After partial trabecular meshwork occlusion, outflow facility decreased to 0.209 ± 0.07 µL/min/mmHg (-32.66% ± 19.53%) and 0.114 ± 0.08 µL/min/mmHg (-66.57% ± 23.08%) in residual high- and low-flow eyes (P = 0.035), respectively. There was a significant difference in the resulting IOP increase (P = 0.034). Conclusions Angiographically determined high- and low-flow regions in the conventional outflow pathways differ in their segmental outflow facility; thus, there is an uneven distribution of local outflow facility across different parts of the TM.
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Affiliation(s)
- Clemens A Strohmaier
- Department of Ophthalmology and Optometry, Kepler University Hospital, Johannes Kepler University, Linz, Austria
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Fiona S McDonnell
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Xiaowei Zhang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Daniel Wanderer
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Robert N Weinreb
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
| | - Alex S Huang
- Hamilton Glaucoma Center, The Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, California, United States
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Segmental outflow dynamics in the trabecular meshwork of living mice. Exp Eye Res 2022; 225:109285. [PMID: 36273576 DOI: 10.1016/j.exer.2022.109285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 12/29/2022]
Abstract
Aqueous humour does not drain uniformly through the trabecular meshwork (TM), but rather follows non-uniform or "segmental" routes. In this study, we examined whether segmental outflow patterns in the TM change over time in living mice and whether such changes are affected by age. Segmental outflow patterns were labelled by constant-pressure infusion of fluorescent tracer microparticles into the anterior chamber of anesthetised C57BL/6J mice at 3 or 8 months of age. Two different tracer colours were infused at separate time points with an interval of Δt = 0, 2, 7 or 14 days. In a separate experiment, one tracer was infused in vivo while the second tracer was infused ex vivo after 2 days. The spatial relationship between the two tracer patterns was analysed using the Pearson's correlation coefficient, r. In 3-month-old mice, there was a time-dependent decay in r, which was near unity at Δt = 0 and near zero at Δt = 14 days. In 8-month-old mice, r remained elevated for 14 days. Segmental outflow patterns measured in young mice ex vivo were not significantly different from those measured in vivo after accounting for the expected changes over 2 days. Therefore, segmental outflow patterns are not static in the TM but redistribute over time, achieving near complete loss of correlation by 2 weeks in young healthy mice. There is an age-related decline in the rate at which segmental outflow patterns redistribute in the TM. Further research is needed to understand the dynamic factors controlling segmental outflow.
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Du R, Xin C, Xu J, Hu J, Wang H, Wang N, Johnstone M. Pulsatile Trabecular Meshwork Motion: An Indicator of Intraocular Pressure Control in Primary Open-Angle Glaucoma. J Clin Med 2022; 11:jcm11102696. [PMID: 35628823 PMCID: PMC9142929 DOI: 10.3390/jcm11102696] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/27/2022] [Accepted: 04/13/2022] [Indexed: 01/03/2023] Open
Abstract
(1) Background: To investigate the value of pulsatile trabecular meshwork (TM) motion in predicting the diurnal intraocular pressure (IOP) fluctuation of primary open-angle glaucoma (POAG). (2) Methods: This cross-sectional study recruited 20 normal patients and 30 patients with POAG. Of the POAG group, 20 had stable diurnal IOP and 10 had high IOP fluctuation. A clinical prototype phase-sensitive optical coherence tomography (PhS-OCT) model was used to measure TM pulsatile motion with maximum velocity (MV) and cumulative displacement (CDisp). (3) Results: MV and CDisp were higher in the external region in both normal and POAG patients. All MV and CDisp reduced significantly in the POAG group (p < 0.001). In the POAG group, except MV in the external region (p = 0.085), MV and CDisp in the nasal area were significantly higher than those in the temporal area (p < 0.05). The MV and CDisp in the external region in the nasal area of POAG patients with high IOP fluctuation were much lower than those with stable IOP (pEMV3 = 0.031, pECDisp3 < 0.001); (4) Conclusions: Pulsatile TM motion reduced in POAG patients relevant to the level of diurnal IOP fluctuation. This study presents the segmental variance of TM stiffness in human living eyes and suggests the clinical potential of the measurement of pulsatile TM motion with PhS-OCT for the evaluation of diurnal IOP fluctuation.
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Affiliation(s)
- Rong Du
- Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; (R.D.); (J.H.); (H.W.); (N.W.)
| | - Chen Xin
- Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; (R.D.); (J.H.); (H.W.); (N.W.)
- Correspondence:
| | - Jingjiang Xu
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China;
| | - Jianping Hu
- Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; (R.D.); (J.H.); (H.W.); (N.W.)
| | - Huaizhou Wang
- Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; (R.D.); (J.H.); (H.W.); (N.W.)
| | - Ningli Wang
- Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; (R.D.); (J.H.); (H.W.); (N.W.)
| | - Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA;
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Lee JY, Akiyama G, Saraswathy S, Xie X, Pan X, Hong YK, Huang AS. Aqueous humour outflow imaging: seeing is believing. Eye (Lond) 2020; 35:202-215. [PMID: 33060830 DOI: 10.1038/s41433-020-01215-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/27/2020] [Accepted: 09/29/2020] [Indexed: 12/22/2022] Open
Abstract
Elevated intraocular pressure (IOP) is the primary risk factor for blindness in glaucoma. IOP is determined by many factors including aqueous humour production and aqueous humour outflow (AHO), where AHO disturbance represents the primary cause of increased IOP. With the recent development of new IOP lowering drugs and Minimally Invasive Glaucoma Surgeries (MIGS), renewed interest has arisen in shedding light on not only how but where AHO is occurring for the trabecular/conventional, uveoscleral/unconventional, and subconjunctival outflow pathways. Historical studies critical to understanding outflow anatomy will be presented, leading to the development of modern imaging methods. New biological behaviours uncovered by modern imaging methods will be discussed with relevance to glaucoma therapies emphasized.
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Affiliation(s)
- Jong Yeon Lee
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Department of Ophthalmology, Gachon University, College of Medicine, Gil Medical Center, Incheon, Korea
| | - Goichi Akiyama
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Jikei School of Medicine, Tokyo, Japan.,Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Sindhu Saraswathy
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Xiaobin Xie
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaojing Pan
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Qindao Eye Hospital of Shandong First Medical University, Shandong Eye Institute, Qindao, China
| | - Young-Kwon Hong
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Alex S Huang
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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