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Iqbal MI, Osman F. Advancing Glaucoma Care in Bangladesh With Minimally Invasive Glaucoma Surgery. Cureus 2024; 16:e60905. [PMID: 38910641 PMCID: PMC11193159 DOI: 10.7759/cureus.60905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2024] [Indexed: 06/25/2024] Open
Abstract
Minimally invasive glaucoma surgery (MIGS) is a cutting-edge approach to treating glaucoma that provides a range of techniques and technology to reduce intraocular pressure (IOP). An 80-year-old man with visually significant cataracts and primary open-angle glaucoma (POAG) underwent combined cataract surgery and TrabEx+ (MicroSurgical Technology, Washington, United States) in his left eye, a unique type of MIGS, as we described in this study. Over the one-year follow-up, this patient showed improved visual function with well-controlled IOP without anti-glaucoma medications.
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Affiliation(s)
- Md Iftekher Iqbal
- Ophthalmology, Bangladesh Eye Hospital, Dhaka, BGD
- Glaucoma, Ispahani Islamia Eye Institute and Hospital, Dhaka, BGD
| | - Fariah Osman
- Ophthalmology, Ispahani Islamia Eye Institute and Hospital, Dhaka, BGD
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2
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Oltmann J, Morell M, Dakroub M, Verma-Fuehring R, Hillenkamp J, Loewen N. VEGF-A-induced changes in distal outflow tract structure and function. Graefes Arch Clin Exp Ophthalmol 2024; 262:537-543. [PMID: 37831170 PMCID: PMC10844149 DOI: 10.1007/s00417-023-06252-5] [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: 03/13/2023] [Revised: 08/17/2023] [Accepted: 09/08/2023] [Indexed: 10/14/2023] Open
Abstract
PURPOSE To investigate changes in distal outflow tract vessels caused by VEGF-A and their impact on outflow. METHODS We compared VEGF-A perfused porcine anterior segments with and without trabecular meshwork (TM) to control eyes. In the first experiment (n=48), we analyzed live changes of the outflow tract with spectral-domain optical coherence tomography (SD-OCT) over 3 h and reconstructed them in 3D. In a second experiment (n=32), we measured the intraocular pressure (IOP) variation in response to VEGF-A over 48 h and computed the outflow facility. RESULTS VEGF-A increased the vessel volume of the distal outflow tract by 16.8±10.6% while control eyes remained unchanged (0.5±6.8%). Volume changes occurred within the first 100 min before plateauing at 140 min. VEGF-A enhanced the outflow facility in eyes without TM by 38.6±25.5% at 24 h as compared to controls (p<0.05). CONCLUSION VEGF-A dilated vessels of the distal outflow tract and increased the outflow facility even after TM removal, pointing to a regulatory mechanism independent of proximal structures.
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Affiliation(s)
- Jannis Oltmann
- Department of Ophthalmology, University Hospital Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany
| | - Mark Morell
- Department of Ophthalmology, University Hospital Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany
| | - Mohamad Dakroub
- Department of Ophthalmology, University Hospital Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany
| | - Raoul Verma-Fuehring
- Department of Ophthalmology, University Hospital Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany
| | - Jost Hillenkamp
- Department of Ophthalmology, University Hospital Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany
| | - Nils Loewen
- Department of Ophthalmology, University Hospital Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany.
- ARTEMIS Eye Centers of Frankfurt, Hanauer Landstr. 147, 60314, Frankfurt, Germany.
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Dakroub M, Verma-Fuehring R, Strzalkowska A, Hillenkamp J, Yousef YA, Loewen NA. Coarsened Exact Matching of Excisional to Plasma-ablative Ab Interno Trabeculectomy. J Curr Glaucoma Pract 2023; 17:9-14. [PMID: 37228309 PMCID: PMC10203335 DOI: 10.5005/jp-journals-10078-1384] [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: 12/16/2021] [Accepted: 11/29/2022] [Indexed: 05/27/2023] Open
Abstract
Aim To compare ab interno trabeculectomy by trabecular meshwork (TM) excision to plasma-mediated ablation in primary open-angle glaucoma (POAG) patients. Methods Retrospectively collected data of TrabEx+ (TEx) (n = 56) and Trabectome (T) (n = 99) patients were compared by coarsened exact matching to reduce confounding and matched based on baseline intraocular pressure (IOP) and age. The primary outcomes were IOP and the number of glaucoma medications. Complications and the need for additional glaucoma surgery were assessed. Patients were followed for up to 1 year. Results A total of 53 TEx could be matched to T. Baseline IOP was 16.5 ± 4.6 mm Hg in both; age was 73.7 ± 8.8 and 71.5 ± 9.9 years in TEx and T, respectively. TEx was taking more medications than T (p < 0.001). IOP was reduced to 14.8 ± 4.3 in TEx and to 13.4 ± 3.4 in T at 6 months, and to 14.9 ± 6.0 (p = 0.13) in TEx and to 14.1 ± 3.8 mm Hg (all p < 0.05) in T at 12 months. Medications were reduced at both 6 and 12 months (p < 0.05). No differences were seen between TEx and T at 6 and 12 months. In TEx, only one serious complication occurred, and two patients required further glaucoma surgery. Conclusion Although both groups had a baseline IOP considered low for ab interno trabeculectomy, IOP and medications were reduced further at 6 and 12 months. IOP reduction did not reach significance in TEx at 12 months. The intergroup comparison did not reveal any significant differences. Both had a low complication rate. Clinical significance This study investigated subtle differences between a plasma-ablative device, the T, and an excisional device, the TEx, by applying coarsened exact matching. IOP and medications were reduced in both groups at 6 and 12 months, although IOP reduction did not reach significance in TEx at 12 months. The intergroup comparison did not reveal any significant differences, with both devices having a low complication rate. How to cite this article Dakroub M, Verma-Fuehring R, Strzalkowska A, et al. Coarsened Exact Matching of Excisional to Plasma-ablative Ab Interno Trabeculectomy. J Curr Glaucoma Pract 2023;17(1):9-14.
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Affiliation(s)
- Mohamad Dakroub
- Department of Ophthalmology, University Eye Hospital of Wuerzburg, Wuerzburg, Germany
| | - Raoul Verma-Fuehring
- Department of Ophthalmology, University Eye Hospital of Wuerzburg, Wuerzburg, Germany
| | - Alicja Strzalkowska
- Department of Ophthalmology, University Eye Hospital of Wuerzburg, Wuerzburg, Germany
| | - Jost Hillenkamp
- Department of Ophthalmology, University Eye Hospital of Wuerzburg, Wuerzburg, Germany
| | - Yousef Al Yousef
- Department of Ophthalmology, University Eye Hospital of Wuerzburg, Wuerzburg, Germany
| | - Nils A Loewen
- Department of Ophthalmology, University Eye Hospital of Wuerzburg, Wuerzburg, Germany; Artemis Eye Centers of Frankfurt, Hanauer Landstraße, Frankfurt, Germany
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Trabeculopuncture as a predictive test of distal outflow resistance in canal-based surgery. Sci Rep 2022; 12:10584. [PMID: 35732782 PMCID: PMC9218089 DOI: 10.1038/s41598-022-13990-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 05/31/2022] [Indexed: 11/16/2022] Open
Abstract
We investigated whether trabeculopuncture (TP) could detect distal outflow resistance to predict the outcome of canal-based glaucoma surgery such as ab interno trabeculectomy (AIT). These procedures have a high utilization in open angle glaucoma, but fail in eyes with an unidentified distal outflow resistance. We assigned 81 porcine eyes to two groups: trial (n = 42) and control (n = 39). At 24 h, four YAG-laser trabeculopunctures were placed nasally, followed by a 180° AIT at the same site at 48 h. The proportion of TP responders between both AIT groups was compared. Histology and outflow canalograms were determined. Both post-TP and post-AIT IOPs were lower than baseline IOP (p = 0.015 and p < 0.01, respectively). The success rates of TP and AIT were 69% and 85.7%, respectively. Sensitivity and specificity values of TP as predictive test for AIT success were 77.7% and 83.3%, respectively. The positive and negative predictive values were 96.6% and 38.5%, respectively. We conclude that a 10% reduction in IOP after TP can be used as a predictor for the success (> 20% IOP decrease) of 180° AIT in porcine eyes.
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Ramjiani V, Mudhar HS, Julian T, Auger G. Sampling trabecular meshwork using TrabEx. BMC Ophthalmol 2021; 21:138. [PMID: 33740938 PMCID: PMC7980329 DOI: 10.1186/s12886-021-01895-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 03/08/2021] [Indexed: 11/10/2022] Open
Abstract
Background To report sampling of the trabecular meshwork using the TrabEx+ (MicroSurgical Technology, Redmond, Washington, USA) device in ab interno trabeculectomy. Specifically, this series focusses upon preservation of the trabecular meshwork architecture for assessment of glaucomatous features using common histopathological techniques. Patients This series features six glaucomatous eyes undergoing TrabEx+ with or without cataract surgery. Three patients had primary open angle glaucoma and the remaining had pigment dispersion glaucoma, ocular hypertension or uveitic glaucoma. Four eyes had simultaneous cataract surgery. Methods Trabecular meshwork was excised using the TrabEx+ device and retrieved using vitreoretinal forceps. The samples were then processed into formalin-fixed paraffin-embedded 4 micron tissue segments and stained with haematoxylin and eosin, periodic acid–Schiff and elastin Van Gieson. Collagen IV was labelled using immunohistochemistry for the purpose of identifying the basement membrane of trabecular beams. Results Presence of trabecular meshwork was confirmed in five of the six samples taken. One of six samples consisted of blood only, but this was expected following early termination of the procedure due to patient restlessness. In the five positive cases trabecular beams with associated trabecular meshwork cells were identified on hematoxylin-eosin and periodic acid–Schiff staining. The beams retained their lamellar structure. The basement membrane underlying the trabecular cells was evident in three specimens, whilst two specimens were of insufficient size for collagen IV labelling. Conclusions This case series illustrates that TrabEx+ can be utilised to successfully retrieve trabecular meshwork samples with sufficient architectural perseveration of the tissue to enable histopathological and laboratory analysis.
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Affiliation(s)
- Vipul Ramjiani
- Department of Ophthalmology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Glossop Rd, England, S10 2JF, Sheffield, UK.
| | - Hardeep-Singh Mudhar
- National Specialist Ophthalmic Pathology Service (NSOPS), Dept of Histopathology-E-Floor, Royal Hallamshire Hospital, Glossop Rd, England, S10 2JF, Sheffield, UK
| | - Thomas Julian
- Department of Ophthalmology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Glossop Rd, England, S10 2JF, Sheffield, UK.,The University of Sheffield, Broomhall, England, S10 2TG, Sheffield, UK
| | - Graham Auger
- Department of Ophthalmology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Glossop Rd, England, S10 2JF, Sheffield, UK
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Konopińska J, Lewczuk K, Jabłońska J, Mariak Z, Rękas M. Microinvasive Glaucoma Surgery: A Review of Schlemm's Canal-Based Procedures. Clin Ophthalmol 2021; 15:1109-1118. [PMID: 33737802 PMCID: PMC7961128 DOI: 10.2147/opth.s293702] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 02/18/2021] [Indexed: 12/12/2022] Open
Abstract
Microinvasive glaucoma surgery has gained popularity over the past decade. It can be performed using three different mechanisms. In the present review, we focused on Schlemm’s canal (SC)-based surgery, which increases aqueous humor (AH) outflow into the aqueous veins by either removal of the trabecular meshwork (TM) or an increase in the tension in the TM. In primary open-angle glaucoma (POAG), the TM is the most likely region for increased AH outflow resistance. Theoretically, removal of the TM can improve the AH outflow; hence, glaucoma specialists focus on microsurgical dissection of the TM. In this review, we analyzed the available literature to examine SC-related microsurgical modalities based on the histopathological proofs of the localization of resistance of the AH outflow. First, we considered the role, anatomy, and physiology of the TM and SC. We referred to studies that describe the mechanisms and potential pathways, related to increased intraocular pressure in the POAG, that are targeted using the SC-related microsurgical interventions. Next, we took a closer look at the gonioscopic tools necessary for an ab-interno approach and explored incision canal surgery: ab-interno trabeculectomy using different instrumentation (Trabectome®, Kahook Dual Blade) and variations of the technique. Thereafter, we discussed ab-interno canaloplasty, explaining the technique and reviewing its effectiveness. Finally, we presented the scope for future research in the field. Although the iStent also targets SC by bypassing it, this device has been reviewed extensively elsewhere.
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Affiliation(s)
- Joanna Konopińska
- Department of Ophthalmology, Medical University of Bialystok, Białystok, Poland
| | - Katarzyna Lewczuk
- Department of Ophthalmology, Military Institute of Medicine, Warsaw, Poland
| | - Joanna Jabłońska
- Department of Ophthalmology, Military Institute of Medicine, Warsaw, Poland
| | - Zofia Mariak
- Department of Ophthalmology, Medical University of Bialystok, Białystok, Poland
| | - Marek Rękas
- Department of Ophthalmology, Military Institute of Medicine, Warsaw, Poland
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Primary outcomes of combined cataract extraction technique with Ab-Interno trabeculectomy and endoscopic Cyclophotocoagulation in patients with primary open angle Glaucoma. BMC Ophthalmol 2020; 20:406. [PMID: 33036581 PMCID: PMC7545548 DOI: 10.1186/s12886-020-01643-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 09/10/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glaucoma surgery have been developed to lower intraocular pressure in a less invasive manner than traditional glaucoma surgery. The purpose of this article is to determine the outcome of using combined phacoemulsification technique, ab-interno trabeculectomy dual blade and endoscopic cyclophotocoagulation (ECP) surgeries in patients with primary open angle glaucoma. METHODS A retrospective case series was performed on 27 consecutive eyes with both primary open-angle glaucoma (POAG) and cataract; each eye was treated with combined phacoemulsification, ab-interno trabeculectomy-Kahook Dual Blade and Endocyclophotocoagulation at Instituto de ojos Oftalmosalud, Lima, Peru, between April 2017 and May 2017. INCLUSION CRITERIA 1) Patients with uncontrolled mild to advanced POAG (according to Glaucoma Grading Scale HODAPP) 2) cataract condition 3) treatment with two or more glaucoma medications due to rapid progression in the visual fields (at least two in a short period of time). Intraocular pressure (IOP), best corrected visual acuity (BCVA) logMAR and number of glaucoma medications were recorded prior to the study, at day 1, week 1, and 1,3,6 and 9 months after surgery. Primary outcome measure was surgical success defined in terms of IOP < 14 mmHg either with no medications (complete success) or with medications (qualified success). RESULTS A total of 27 eyes from 27 patients were included. The mean basal IOP was 17.0 ± 3.7 mmHg and postoperatively was 11.6 ± 1.9 mmHg and 11.4 ± 1.8 mmHg (P < 0.001) at 6 and 9 months respectively. Glaucoma medications decreased from 1.9 ± 1.4 to 0.56 ± 1.05 at 9 month follow-ups (P < 0.001). Preoperative best corrected visual acuity (BCVA) showed and improvement from 0.4 ± 0.4 LogMAR to 0.2 ± 0.4 logMAR at 9 months. The main complication was blood reflux intra-operatively (66.7%), which resolved without re-operation. The mean IOP was reduced by 32.9% from baseline and the surgical success was 92,6%, (complete success 70,3% and qualified success 29,6%) at 9 months. CONCLUSIONS In patients with POAG, combined treatment with phacoemulsification, ab-interno trabeculectomy and endoscopic cyclophotocoagulation effectively reduced IOP and glaucoma medication dependence.
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Chen S, Waxman S, Wang C, Atta S, Loewen R, Loewen NA. Dose-dependent effects of netarsudil, a Rho-kinase inhibitor, on the distal outflow tract. Graefes Arch Clin Exp Ophthalmol 2020; 258:1211-1216. [PMID: 32372330 PMCID: PMC7237522 DOI: 10.1007/s00417-020-04691-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/24/2020] [Accepted: 04/07/2020] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To characterize the effects of netarsudil on the aqueous humor outflow tract distal to the trabecular meshwork (TM). We hypothesized that netarsudil increases outflow facility in eyes with and without circumferential ab interno trabeculectomy (AIT) that removes the TM. METHODS Sixty-four porcine anterior segment cultures were randomly assigned to groups with (n = 32) and without circumferential AIT (n = 32). Cultures were exposed to 0.1, 1, and 10 μM netarsudil (N = 8 eyes per concentration). For each concentration, IOP and vessel diameters were compared with their respective pretreatment baselines. Outflow tract vessel diameters were assessed by spectral-domain optical coherence tomography (SDOCT) and rendered in 4D (XYZ time series). RESULTS Netarsudil at 1 μM reduced IOP both in eyes with TM (- 0.60 ± 0.24 mmHg, p = 0.01) and in eyes without TM (- 1.79 ± 0.42 mmHg, p < 0.01). At this concentration, vessels of the distal outflow tract dilated by 72%. However, at 0.1 μM netarsudil elevated IOP in eyes with TM (1.59 ± 0.36 mmHg, p < 0.001) as well as in eyes without TM (0.23 ± 0.32 mmHg, p < 0.001). Vessels of the distal outflow tract constricted by 31%. Similarly, netarsudil at a concentration of 10 μM elevated IOP both in eyes with TM (1.91 ± 0.193, p < 0.001) and in eyes without TM (3.65 ± 0.86 mmHg, p < 0.001). At this concentration, outflow tract vessels constricted by 27%. CONCLUSION In the porcine anterior segment culture, the dose-dependent IOP changes caused by netarsudil matched the diameter changes of distal outflow tract vessels. Hyper- and hypotensive properties of netarsudil persisted after TM removal.
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Affiliation(s)
- Si Chen
- Department of Ophthalmology, University of Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Department of Ophthalmology, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Chao Wang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Department of Ophthalmology, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Sarah Atta
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ralitsa Loewen
- Department of Ophthalmology, University of Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nils A Loewen
- Department of Ophthalmology, University of Würzburg, Josef-Schneider-Straße 11, 97080, Würzburg, Germany. .,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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Wang C, Dang Y, Shah P, Esfandiari H, Hong Y, Loewen RT, Waxman S, Atta S, Xia X, Loewen NA. Intraocular pressure reduction in a pigmentary glaucoma model by Goniotome Ab interno trabeculectomy. PLoS One 2020; 15:e0231360. [PMID: 32298335 PMCID: PMC7162452 DOI: 10.1371/journal.pone.0231360] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/21/2020] [Indexed: 01/08/2023] Open
Abstract
PURPOSE To investigate whether microsurgical excision of trabecular meshwork (TM) in an ex vivo pigmentary glaucoma model can normalize the hypertensive phenotype. METHODS Eight eyes of a porcine pigmentary glaucoma model underwent 90° of microsurgical TM excision with an aspirating dual-blade (Goniotome (G)). 24 hours later, additional 90° of TM were removed. Anterior segments with sham surgeries served as the control (C). Outflow facility and intraocular pressure (IOP) were analyzed. Histology with hematoxylin and eosin (H&E) was obtained. RESULTS After the first 90° TM excision, IOP was significantly lower in G (10.2±2.4 mmHg, n = 7) than C (20.0±2.0mmHg, n = 8, P<0.01). Outflow facility in G (0.38±0.07 μl/min/mmHg) was higher than C (0.16±0.02 μl/min/mmHg, P<0.01). After the second 90° TM excision, IOP in G (6.46±0.81 mmHg, n = 7) was significantly lower than C (20.3±1.7 mmHg, n = 8, P<0.001), while the outflow facility in G (0.50±0.05 μl/min/mmHg, n = 7) was higher than C (0.16±0.01 μl/min/mmHg, n = 8, P<0.001). Compared to the first excision, excision of an additional 90° did not change of IOP (P = 0.20) or outflow facility (P = 0.17) further. CONCLUSIONS Excision of 90° of TM in a pigmentary glaucoma model using an aspirating dual-blade decreased IOP and increased outflow facility.
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Affiliation(s)
- Chao Wang
- Department of Ophthalmology, University of Würzburg, Würzburg, Germany
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Yalong Dang
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Priyal Shah
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Hamed Esfandiari
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Ying Hong
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Ralitsa T. Loewen
- Department of Ophthalmology, University of Würzburg, Würzburg, Germany
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Sarah Atta
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Xiaobo Xia
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Nils A. Loewen
- Department of Ophthalmology, University of Würzburg, Würzburg, Germany
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Waxman S, Wang C, Dang Y, Hong Y, Esfandiari H, Shah P, Lathrop KL, Loewen RT, Loewen NA. Structure-Function Changes of the Porcine Distal Outflow Tract in Response to Nitric Oxide. Invest Ophthalmol Vis Sci 2019; 59:4886-4895. [PMID: 30347083 PMCID: PMC6181305 DOI: 10.1167/iovs.18-24943] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Purpose To correlate outflow function and outflow tract vessel diameter changes induced by nitric oxide (NO). Methods In a porcine anterior segment perfusion model, the effects of a nitric oxide donor (100 μM DETA-NO) on outflow facility were compared with controls (n = 8 per group) with trabecular meshwork (TM) and after circumferential ab interno trabeculectomy (AIT). Outflow structures were assessed with spectral-domain optical coherence tomography (SD-OCT) before and after NO, or an NO synthase inhibitor (100 μM L-NAME) and the vasoconstrictor, endothelin-1 (100 pg/mL ET-1). Scans were processed with a custom macroscript and aligned for automated reslicing and quantification of cross-sectional outflow tract areas (CSA). Results The facility increased after DETA-NO (Δ of 0.189 ± 0.081 μL/min·mm Hg, P = 0.034) and AIT (Δ of 0.251 ± 0.094 μL/min·mm Hg, P = 0.009), respectively. Even after AIT, DETA-NO increased the facility by 61.5% (Δ of 0.190 ± 0.074 μL/min·mm Hg, P = 0.023) and CSA by 13.9% (P < 0.001). L-NAME + ET-1 decreased CSA by -8.6% (P < 0.001). NO increased the diameter of focal constrictions 5.0 ± 3.8-fold. Conclusions NO can dilate vessels of the distal outflow tract and increase outflow facility in a TM-independent fashion. There are short, focally constricting vessel sections that display large diameter changes and may have a substantial impact on outflow.
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Affiliation(s)
- Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Chao Wang
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States.,Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yalong Dang
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Ying Hong
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States.,Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Hamed Esfandiari
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Priyal Shah
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Kira L Lathrop
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Ralitsa T Loewen
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Nils A Loewen
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
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11
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Waxman S, Loewen RT, Dang Y, Watkins SC, Watson AM, Loewen NA. High-Resolution, Three-Dimensional Reconstruction of the Outflow Tract Demonstrates Segmental Differences in Cleared Eyes. Invest Ophthalmol Vis Sci 2019; 59:2371-2380. [PMID: 29847643 PMCID: PMC5939687 DOI: 10.1167/iovs.17-23075] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Purpose The rate of conventional aqueous humor outflow is the highest nasally. We hypothesized that this is reflected in regionally different outflow structures and analyzed the entire limbus by high-resolution, full-thickness ribbon-scanning confocal microscopy (RSCM). Methods We perfused pig eyes by anterior chamber cannulation with eight lectin-fluorophore conjugates, followed by optical clearance with benzyl alcohol benzyl benzoate (BABB). RSCM and advanced analysis software (Imaris) were used to reconstruct a three-dimensional (3D), whole-specimen rendering of the perilimbal outflow structures. We performed morphometric analyses of the outflow tract from the level of the trabecular meshwork (TM) to the scleral vascular plexus (SVP). Results Except for pigmented structures, BABB cleared the entire eye. Rhodamine-conjugated Glycine max agglutinin (soybean [SBA]) labeled the outflow tract evenly and retained fluorescence for months. RSCM produced terabyte-sized files allowing for in silico dissection of outflow tract vessels at a high resolution and in 3D. Networks of interconnected lumens were traced from the TM to downstream drainage structures. The collector channel (CC) volumes were 10 times smaller than the receiving SVP vessels, the largest of which were in the inferior limbus. Proximal CC diameters were up to four times the size of distal diameters and more elliptical at their proximal ends. The largest CCs were found in the superonasal and inferonasal quadrants where the highest outflow occurs. Conclusion RSCM of cleared eyes enabled high-resolution, volumetric analysis of the outflow tract. The proximal structures had greater diameters nasally, whereas the SVP was larger in the inferior limbus.
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Affiliation(s)
- Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Ralitsa T Loewen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Yalong Dang
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Simon C Watkins
- Center for Biologic Imaging and the Department of Cellular Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Alan M Watson
- Center for Biologic Imaging and the Department of Cellular Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Nils A Loewen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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12
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Abstract
The Kahook Dual Blade (New World Medical, Rancho Cucamonga, CA, USA) is a novel goniotomy instrument for opening Schlemm's canal. Performing the procedure is comparable to the Trabectome (Neomedix, Tustin, CA, USA) under gonioscopic control with the major difference that the trabeculectomy is created by a dual blade instead of electroablation. The currently available clinical data are limited to a small number of retrospective studies with ≤1 year of follow-up. Based on these data and in line with the author's personal experience, the Kahook Dual Blade seems comparable to the Trabectome regarding effectiveness as well as intraoperative and postoperative complications, such as intraocular pressure (IOP) elevation and hyphema.
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13
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Dang Y, Wang C, Shah P, Waxman S, Loewen RT, Hong Y, Esfandiari H, Loewen NA. Outflow enhancement by three different ab interno trabeculectomy procedures in a porcine anterior segment model. Graefes Arch Clin Exp Ophthalmol 2018; 256:1305-1312. [PMID: 29721662 PMCID: PMC7804591 DOI: 10.1007/s00417-018-3990-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/29/2018] [Accepted: 04/11/2018] [Indexed: 12/11/2022] Open
Abstract
PURPOSE To evaluate three different microincisional ab interno trabeculectomy procedures in a porcine eye perfusion model. METHODS In perfused porcine anterior segments, 90° of trabecular meshwork (TM) was ablated using the Trabectome (T; n = 8), Goniotome (G; n = 8), or Kahook device (K; n = 8). After 24 h, additional 90° of TM was removed. Intraocular pressure (IOP) and outflow facility were measured at 5 and 10 μl/min perfusion to simulate an elevated IOP. Structure and function were assessed with canalograms and histology. RESULTS At 5 μl/min infusion rate, T resulted in a greater IOP reduction than G or K from baseline (76.12% decrease versus 48.19% and 47.96%, P = 0.013). IOP reduction between G and K was similar (P = 0.420). Removing another 90° of TM caused an additional IOP reduction only in T and G but not in K. Similarly, T resulted in the largest increase in outflow facility at 5 μl/min compared with G and K (first ablation, 3.41 times increase versus 1.95 and 1.87; second ablation, 4.60 versus 2.50 and 1.74) with similar results at 10 μl/min (first ablation, 3.28 versus 2.29 and 1.90 (P = 0.001); second ablation, 4.10 versus 3.01 and 2.01 (P = 0.001)). Canalograms indicated circumferential flow beyond the ablation endpoints. CONCLUSIONS T, G, and K significantly increased the outflow facility. In this model, T had a larger effect than G and K.
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Affiliation(s)
- Yalong Dang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA
| | - Chao Wang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Priyal Shah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA
| | - Ralitsa T Loewen
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA
| | - Ying Hong
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA
| | - Hamed Esfandiari
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA
| | - Nils A Loewen
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop St, Suite 819, Pittsburgh, PA, 15213, USA.
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14
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Dang YL, Wang X, Dai WW, Huang P, Loewen NA, Zhang C. Two-year outcomes of ab interno trabeculectomy with the Trabectome for Chinese primary open angle glaucoma: a retrospective multicenter study. Int J Ophthalmol 2018; 11:945-950. [PMID: 29977805 DOI: 10.18240/ijo.2018.06.08] [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: 12/18/2017] [Accepted: 04/28/2018] [Indexed: 11/23/2022] Open
Abstract
AIM To evaluate the 2-year efficacy and safety of ab interno trabeculectomy with the Trabectome in Chinese primary open angle glaucoma (POAG) patients. METHODS This was a multicenter, retrospective, observational study and included POAG patients with or without visually-significant cataracts. The Chinese patients were enrolled from three glaucoma centers and a group of comparable Japanese POAG patients was analyzed from our international Trabectome database. The patients received Trabectome or a combined surgery with phacoemulsification and intraocular lens implantation. The primary outcome was intraocular pressure (IOP) reduction. Secondary outcomes included reduction of glaucoma medications, surgical complications, and success at 2y. Success was defined as: 1) IOP≤21 mm Hg and at least 20% IOP reduction from baseline after 3mo at any two consecutive visits; 2) no additional glaucoma surgery required. RESULTS A total of 42 Chinese POAG patients from three glaucoma centers were enrolled. Twelve patients underwent Trabectome surgery combined with phacoemulsification and intraocular lens implantation while the remainder underwent Trabectome surgery alone. Thirteen patients had a history of failed glaucoma surgery and were considered as complicated cases. In China data, the mean preoperative IOP was 21.4±1.23 mm Hg. The Trabectome lowered IOP to 17.9±1.8 mm Hg at 2y (P=0.05). The number of glaucoma medications also decreased significantly from a baseline of 2.0±0.9 to 1.1±0.8 at 2y post-surgery (P=0.04). The overall 2-year success rate was 78%, with patients undergoing combined surgery having a higher success rate compared with those undergoing Trabectome surgery alone (100% vs 76%). In Japan data, the mean preoperative IOP was 20.8±7.7 mm Hg. The Trabectome lowered IOP to 12.20±2.0 mm Hg at 2y. The number of glaucoma medications also decreased significantly from a baseline of 2.1±0.9 to 3.4±0.6 at 2y post-surgery. In all patients, no major complications were seen. CONCLUSION Surgery with the Trabectome appears to be an efficient and safe procedure in Chinese POAG patients in the long-term.
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Affiliation(s)
- Ya-Long Dang
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China.,Beijing Key Laboratory of Restoration of Damaged Optic Nerve, Peking University Third Hospital, Beijing 100191, China.,Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.,Department of Ophthalmology, Sanmenxia Central Hospital, Sanmenxia 472000, Henan Province, China
| | - Xiao Wang
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China
| | - Wan-Wei Dai
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China.,Beijing Key Laboratory of Restoration of Damaged Optic Nerve, Peking University Third Hospital, Beijing 100191, China.,Institution of Population Research, Peking University, Beijing 100191, China
| | - Ping Huang
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China
| | - Nils A Loewen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Chun Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China.,Beijing Key Laboratory of Restoration of Damaged Optic Nerve, Peking University Third Hospital, Beijing 100191, China
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Dang Y, Waxman S, Wang C, Loewen RT, Sun M, Loewen NA. A porcine ex vivo model of pigmentary glaucoma. Sci Rep 2018; 8:5468. [PMID: 29615741 PMCID: PMC5882895 DOI: 10.1038/s41598-018-23861-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 03/16/2018] [Indexed: 11/11/2022] Open
Abstract
Pigment dispersion can lead to pigmentary glaucoma, a poorly understood condition of younger myopic eyes with fluctuating high intraocular pressure. It has been difficult to investigate its pathogenesis without a model similar to human eyes in size and behavior. Here we present a porcine ex vivo model that recreates several features of pigmentary glaucoma, including intraocular hypertension, accumulation of pigment in the trabecular meshwork, and declining phagocytosis. We found that trabecular meshwork cells regulate outflow, form actin stress fibers, and have a decreased phagocytic activity. Gene expression microarrays and a pathway analysis of TM monolayers as well as ex vivo anterior segment perfusion cultures indicated that RhoA plays a central role in regulating the cytoskeleton, motility, and phagocytosis in the trabecular meshwork, providing new insights and targets to investigate in pigmentary glaucoma.
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Affiliation(s)
- Yalong Dang
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America
| | - Susannah Waxman
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America
| | - Chao Wang
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
| | - Ralitsa T Loewen
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America
| | - Ming Sun
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America
| | - Nils A Loewen
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America.
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16
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Dang YL, Cen YJ, Hong Y, Huang P, Wang NL, Wang C, Zhang C. Safety and Efficiency of Trabectome-mediated Trabecular Meshwork Ablation for Chinese Glaucoma Patients: A Two-year, Retrospective, Multicentre Study. Chin Med J (Engl) 2018; 131:420-425. [PMID: 29451146 PMCID: PMC5830826 DOI: 10.4103/0366-6999.225050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND The aim of the study was to evaluate the long-term safety and efficacy of the Trabectome for Chinese glaucoma patients. METHODS This was a multicenter, retrospective, observational study. Glaucoma patients, except those with neovascular glaucoma, with/without a visually significant cataract were enrolled. The patients received Trabectome or a combined surgery with phacoemulsification and intraocular lens implantation. The primary outcome evaluation was a reduction in intraocular pressure (IOP), and the secondary outcomes were a reduction in glaucoma medication, the 2-year success percentages, and complications. Success was defined as an IOP <21 mmHg and at least a 20% IOP reduction from baseline after 3 months for any two consecutive visits, without additional glaucoma surgery. The data were processed using the R Stats Package version 3.0.0. The Wilcoxon test was used to compare the postoperative IOP and the number of glaucoma medications with baselines. The Kaplan-Meier test was used to calculate the 2-year success percentage. The risk factors related to Trabectome failure were determined by logistic regression. RESULTS A total of 120 glaucoma patients were enrolled. The Trabectome efficiently reduced the IOP from a baseline of 22.8 ± 1.34 mmHg to 17.6 ± 0.96 mmHg, and the use of glaucoma medications from 2.2 ± 0.17 mmHg to 1.4 ± 0.21 in a 2-year follow-up (both, P < 0.01). The overall success percentage was 80%. No risk factor related to Trabectome failure was identified. No vision-threatening complication was observed. Ten patients, who required secondary glaucoma surgery, all reached the target IOP. CONCLUSIONS In a 2-year follow-up, Trabectome was an efficient and safe procedure for Chinese glaucoma patients.
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Affiliation(s)
- Ya-Long Dang
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China
| | - Yu-Jie Cen
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China
| | - Ying Hong
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China
| | - Ping Huang
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China
| | - Ning-Li Wang
- Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing 100005, China
| | - Chao Wang
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Chun Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China
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17
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Esfandiari H, Pakravan M, Loewen NA, Yaseri M. Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy. F1000Res 2017; 6:1898. [PMID: 29333242 PMCID: PMC5747341 DOI: 10.12688/f1000research.12904.2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/12/2017] [Indexed: 11/20/2022] Open
Abstract
Background: To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP) on the success rate of trabeculectomy. Methods: In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS). Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC). Results: The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911). IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively.) The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971) with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91%) and a specificity of 87.5% (95% CI: 53 to 98%). Conclusions: IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy. An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.
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Affiliation(s)
- Hamed Esfandiari
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mohammad Pakravan
- Ophthalmic Epidemiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nils A Loewen
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mehdi Yaseri
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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18
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Dang Y, Waxman S, Wang C, Jensen A, Loewen RT, Bilonick RA, Loewen NA. Freeze-thaw decellularization of the trabecular meshwork in an ex vivo eye perfusion model. PeerJ 2017; 5:e3629. [PMID: 28828244 PMCID: PMC5560227 DOI: 10.7717/peerj.3629] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/10/2017] [Indexed: 12/13/2022] Open
Abstract
Objective The trabecular meshwork (TM) is the primary substrate of outflow resistance in glaucomatous eyes. Repopulating diseased TM with fresh, functional TM cells might be a viable therapeutic approach. Decellularized TM scaffolds have previously been produced by ablating cells with suicide gene therapy or saponin, which risks incomplete cell removal or dissolution of the extracellular matrix, respectively. We hypothesized that improved trabecular meshwork cell ablation would result from freeze-thaw cycles compared to chemical treatment. Materials and Methods We obtained 24 porcine eyes from a local abattoir, dissected and mounted them in an anterior segment perfusion within two hours of sacrifice. Intraocular pressure (IOP) was recorded continuously by a pressure transducer system. After 72 h of IOP stabilization, eight eyes were assigned to freeze-thaw (F) ablation (−80 °C × 2), to 0.02% saponin (S) treatment, or the control group (C), respectively. The TM was transduced with an eGFP expressing feline immunodeficiency viral (FIV) vector and tracked via fluorescent microscopy to confirm ablation. Following treatment, the eyes were perfused with standard tissue culture media for 180 h. TM histology was assessed by hematoxylin and eosin staining. TM viability was evaluated by a calcein AM/propidium iodide (PI) assay. The TM extracellular matrix was stained with Picro Sirius Red. We measured IOP and modeled it with a linear mixed effects model using a B-spline function of time with five degrees of freedom. Results F and S experienced a similar IOP reduction of 30% from baseline (P = 0.64). IOP reduction of about 30% occurred in F within 24 h and in S within 48 h. Live visualization of eGFP demonstrated that F conferred a complete ablation of all TM cells and only a partial ablation in S. Histological analysis and Picro Sirius staining confirmed that no TM cells survived in F while the extracellular matrix remained. The viability assay showed very low PI and no calcein staining in F in contrast to many PI-labeled, dead TM cells and calcein-labeled viable TM cells in S. Conclusion We developed a rapid TM ablation method that uses cyclic freezing that is free of biological or chemical agents and able to produce a decellularized TM scaffold with preserved TM extracellular matrix in an organotypic perfusion culture.
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Affiliation(s)
- Yalong Dang
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PAUnited States of America
| | - Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PAUnited States of America
| | - Chao Wang
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PAUnited States of America.,Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
| | - Adrianna Jensen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PAUnited States of America
| | - Ralitsa T Loewen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PAUnited States of America
| | - Richard A Bilonick
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PAUnited States of America
| | - Nils A Loewen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PAUnited States of America
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