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Sun MT, Cotton RM, Charoenkijkajorn C, Garcia-Sanchez J, Dalal R, Xia X, Lin JH, Singh K, Goldberg JL, Liu WW. Evaluation of Verteporfin as a Novel Antifibrotic Agent in a Rabbit Model of Glaucoma Filtration Surgery: A Pilot Study. Ophthalmol Sci 2024; 4:100448. [PMID: 38261964 PMCID: PMC10797546 DOI: 10.1016/j.xops.2023.100448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/20/2023] [Accepted: 12/04/2023] [Indexed: 01/25/2024]
Abstract
Purpose Verteporfin is a benzoporphyrin derivative which is Food and Drug Administration-approved for treatment of choroidal neovascularization in conjunction with photodynamic therapy. It has been shown to prevent fibrosis and scar formation in several organs and represents a promising novel antifibrotic agent for glaucoma surgery. The goal of this study is to determine the effect of verteporfin on wound healing after glaucoma filtration surgery. Design Preclinical study using a rabbit model of glaucoma filtration surgery. Subjects Eight New Zealand white rabbits underwent glaucoma filtration surgery in both eyes. Methods Eyes were randomized into 4 study groups to receive a postoperative subconjunctival injection of 1 mg/mL verteporfin (n = 4), 0.4 mg/mL mitomycin C (MMC; n = 4), 0.4 mg/mL MMC + 1 mg/mL verteporfin (n = 4), or balanced salt solution (BSS) control (n = 4). Bleb survival, vascularity, and morphology were graded using a standard scale over a 30-day period, and intraocular pressure (IOP) was monitored. At 30 days postoperative or surgical failure, histology was performed to evaluate for inflammation, local toxicity, and scarring. Main Outcome Measures The primary outcome measure was bleb survival. Secondary outcome measures were IOP, bleb morphology, and bleb histology. Results Compared to BSS control blebs, verteporfin-treated blebs demonstrated a trend toward increased surgical survival (mean 9.8 vs. 7.3 days, log rank P = 0.08). Mitomycin C-treated blebs survived significantly longer than verteporfin-treated blebs (log rank P = 0.009), with all but 1 MMC-treated bleb still surviving at postoperative day 30. There were no significant differences in survival between blebs treated with combination verteporfin + MMC and MMC alone. Mitomycin C-treated blebs were less vascular than verteporfin-treated blebs (mean vascularity score 0.3 ± 0.5 for MMC vs. 1.0 ± 0.0 for verteporfin, P < 0.01). Bleb histology did not reveal any significant toxicity in verteporfin-treated eyes. There were no significant differences in inflammation or scarring across groups. Conclusions Although verteporfin remained inferior to MMC with regard to surgical survival, there was a trend toward increased survival compared with BSS control and it had an excellent safety profile. Further studies with variations in verteporfin dosage and/or application frequency are needed to assess whether this may be a useful adjunct to glaucoma surgery. Financial Disclosures Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Michelle T. Sun
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Renee M. Cotton
- Department of Comparative Medicine, Stanford University, Palo Alto, California
| | - Chaow Charoenkijkajorn
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Julian Garcia-Sanchez
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Roopa Dalal
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Xin Xia
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Jonathan H. Lin
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Kuldev Singh
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Jeffrey L. Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - Wendy W. Liu
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
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Bhuckory MB, Monkongpitukkul N, Shin A, Goldstein AK, Jensen N, Shah SV, Pham-Howard D, Butt E, Dalal R, Galambos L, Mathieson K, Kamins T, Palanker D. Enhancing Prosthetic Vision by Upgrade of a Subretinal Photovoltaic Implant in situ. bioRxiv 2024:2024.04.15.589465. [PMID: 38659843 PMCID: PMC11042236 DOI: 10.1101/2024.04.15.589465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
In patients with atrophic age-related macular degeneration, subretinal photovoltaic implant (PRIMA) provided visual acuity up to 20/440, matching its 100μm pixels size. Next-generation implants with smaller pixels should significantly improve the acuity. This study in rats evaluates removal of a subretinal implant, replacement with a newer device, and the resulting grating acuity in-vivo. Six weeks after the initial implantation with planar and 3-dimensional devices, the retina was re-detached, and the devices were successfully removed. Histology demonstrated a preserved inner nuclear layer. Re-implantation of new devices into the same location demonstrated retinal re-attachment to a new implant. New devices with 22μm pixels increased the grating acuity from the 100μm capability of PRIMA implants to 28μm, reaching the limit of natural resolution in rats. Reimplanted devices exhibited the same stimulation threshold as for the first implantation of the same implants in a control group. This study demonstrates the feasibility of safely upgrading the subretinal photovoltaic implants to improve prosthetic visual acuity.
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Affiliation(s)
- Mohajeet B Bhuckory
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94303, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Nicharee Monkongpitukkul
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Faculty of Medicine, Prince of Songkla University, Thailand
| | - Andrew Shin
- Department of Material Science, Stanford University, Stanford, CA, USA
| | | | - Nathan Jensen
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Sarthak V Shah
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Davis Pham-Howard
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94303, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Emma Butt
- Department of Physics, University of Strathclyde, Glasgow, Scotland, UK
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Ludwig Galambos
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94303, USA
| | - Keith Mathieson
- Department of Physics, University of Strathclyde, Glasgow, Scotland, UK
| | - Theodore Kamins
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94303, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
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3
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Heng K, Young BK, Li B, Nies AD, Xia X, Wen RR, Dalal R, Bramblett GT, Holt AW, Cleland JM, Harris JN, Wu AY, Goldberg JL. BDNF and cAMP are neuroprotective in a porcine model of traumatic optic neuropathy. JCI Insight 2024; 9:e172935. [PMID: 38194296 DOI: 10.1172/jci.insight.172935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 12/28/2023] [Indexed: 01/10/2024] Open
Abstract
Traumatic optic neuropathy (TON) is a devastating condition that can occur after blunt or penetrating trauma to the head, leading to visual impairment or blindness. Despite these debilitating effects, no clinically available therapeutic targets neuroprotection or promotes axon regeneration in this or any optic neuropathy. Limited data in large-animal models are a major obstacle to advancing treatments toward clinical therapeutics. To address this issue, we refined a surgical model of TON in Yucatan minipigs. First, we validated the model by demonstrating visual impairment by flash visual-evoked potential and retinal ganglion cell degeneration and death. Next, we developed and optimized a delivery method and nontoxic dosing of intravitreal brain-derived neurotrophic factor (BDNF) and cAMP. Finally, we showed that intravitreal injection of BDNF and cAMP rescued visual function and protected against retinal ganglion cell death and optic nerve axon degeneration. Together these data in a preclinical large-animal model advance our understanding of and ability to model TON and further identify and develop candidate clinical therapeutics.
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Affiliation(s)
- Kathleen Heng
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
- Neurosciences Interdepartmental Program, Stanford University, Stanford, California, USA
| | - Brent K Young
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
| | - BaoXiang Li
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
| | - Ashley D Nies
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
| | - Xin Xia
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
| | - Runxia R Wen
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
| | - Roopa Dalal
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
| | | | - Andrew W Holt
- United States Army Institute of Surgical Research, Fort Sam Houston, Texas, USA
| | - Jeffery M Cleland
- Department of Optometry, University of the Incarnate Word, San Antonio, Texas, USA
| | - Jason N Harris
- United States Army Institute of Surgical Research, Fort Sam Houston, Texas, USA
| | - Albert Y Wu
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, School of Medicine, and
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4
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Cameron EG, Nahmou M, Toth AB, Heo L, Tanasa B, Dalal R, Yan W, Nallagatla P, Xia X, Hay S, Knasel C, Stiles TL, Douglas C, Atkins M, Sun C, Ashouri M, Bian M, Chang KC, Russano K, Shah S, Woodworth MB, Galvao J, Nair RV, Kapiloff MS, Goldberg JL. A molecular switch for neuroprotective astrocyte reactivity. Nature 2024; 626:574-582. [PMID: 38086421 DOI: 10.1038/s41586-023-06935-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 12/05/2023] [Indexed: 01/27/2024]
Abstract
The intrinsic mechanisms that regulate neurotoxic versus neuroprotective astrocyte phenotypes and their effects on central nervous system degeneration and repair remain poorly understood. Here we show that injured white matter astrocytes differentiate into two distinct C3-positive and C3-negative reactive populations, previously simplified as neurotoxic (A1) and neuroprotective (A2)1,2, which can be further subdivided into unique subpopulations defined by proliferation and differential gene expression signatures. We find the balance of neurotoxic versus neuroprotective astrocytes is regulated by discrete pools of compartmented cyclic adenosine monophosphate derived from soluble adenylyl cyclase and show that proliferating neuroprotective astrocytes inhibit microglial activation and downstream neurotoxic astrocyte differentiation to promote retinal ganglion cell survival. Finally, we report a new, therapeutically tractable viral vector to specifically target optic nerve head astrocytes and show that raising nuclear or depleting cytoplasmic cyclic AMP in reactive astrocytes inhibits deleterious microglial or macrophage cell activation and promotes retinal ganglion cell survival after optic nerve injury. Thus, soluble adenylyl cyclase and compartmented, nuclear- and cytoplasmic-localized cyclic adenosine monophosphate in reactive astrocytes act as a molecular switch for neuroprotective astrocyte reactivity that can be targeted to inhibit microglial activation and neurotoxic astrocyte differentiation to therapeutic effect. These data expand on and define new reactive astrocyte subtypes and represent a step towards the development of gliotherapeutics for the treatment of glaucoma and other optic neuropathies.
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Affiliation(s)
- Evan G Cameron
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
| | - Michael Nahmou
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Anna B Toth
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Lyong Heo
- Stanford Center for Genomics and Personalized Medicine, Stanford University, Palo Alto, CA, USA
| | - Bogdan Tanasa
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Roopa Dalal
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Wenjun Yan
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Pratima Nallagatla
- Stanford Center for Genomics and Personalized Medicine, Stanford University, Palo Alto, CA, USA
| | - Xin Xia
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Sarah Hay
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Cara Knasel
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | | | | | - Melissa Atkins
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Catalina Sun
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Masoumeh Ashouri
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Minjuan Bian
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Kun-Che Chang
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Kristina Russano
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Sahil Shah
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
- University of California, San Diego, La Jolla, CA, USA
| | - Mollie B Woodworth
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Joana Galvao
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Ramesh V Nair
- Stanford Center for Genomics and Personalized Medicine, Stanford University, Palo Alto, CA, USA
| | - Michael S Kapiloff
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
- Department of Medicine and Stanford Cardiovascular Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Jeffrey L Goldberg
- Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
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5
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Zhu Y, Garcia-Sanchez J, Dalal R, Sun Y, Kapiloff MS, Goldberg JL, Liu WW. Differential expression of PIEZO1 and PIEZO2 mechanosensitive channels in ocular tissues implicates diverse functional roles. Exp Eye Res 2023; 236:109675. [PMID: 37820892 PMCID: PMC10843266 DOI: 10.1016/j.exer.2023.109675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/08/2023] [Accepted: 10/08/2023] [Indexed: 10/13/2023]
Abstract
PIEZO1 and PIEZO2 are mechanosensitive ion channels that regulate many important physiological processes including vascular blood flow, touch, and proprioception. As the eye is subject to mechanical stress and is highly perfused, these channels may play important roles in ocular function and intraocular pressure regulation. PIEZO channel expression in the eye has not been well defined, in part due to difficulties in validating available antibodies against PIEZO1 and PIEZO2 in ocular tissues. It is also unclear if PIEZO1 and PIEZO2 are differentially expressed. To address these questions, we used single-molecule fluorescence in situ hybridization (smFISH) together with transgenic reporter mice expressing PIEZO fusion proteins under the control of their endogenous promoters to compare the expression and localization of PIEZO1 and PIEZO2 in mouse ocular tissues relevant to glaucoma. We detected both PIEZO1 and PIEZO2 expression in the trabecular meshwork, ciliary body, and in the ganglion cell layer (GCL) of the retina. Piezo1 mRNA was more abundantly expressed than Piezo2 mRNA in these ocular tissues. Piezo1 but not Piezo2 mRNA was detected in the inner nuclear layer and outer nuclear layer of the retina. Our results suggest that PIEZO1 and PIEZO2 are differentially expressed and may have distinct roles as mechanosensors in glaucoma-relevant ocular tissues.
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Affiliation(s)
- Ying Zhu
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Julian Garcia-Sanchez
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Roopa Dalal
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yang Sun
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Michael S Kapiloff
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Wendy W Liu
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
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6
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Liu P, Chen W, Jiang H, Huang H, Liu L, Fang F, Li L, Feng X, Liu D, Dalal R, Sun Y, Jafar-Nejad P, Ling K, Rigo F, Ye J, Hu Y. Differential effects of SARM1 inhibition in traumatic glaucoma and EAE optic neuropathies. Mol Ther Nucleic Acids 2023; 32:13-27. [PMID: 36950280 PMCID: PMC10025007 DOI: 10.1016/j.omtn.2023.02.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/23/2023] [Indexed: 03/03/2023]
Abstract
Optic neuropathy is a group of optic nerve (ON) diseases with progressive degeneration of ON and retinal ganglion cells (RGCs). The lack of neuroprotective treatments is a central challenge for this leading cause of irreversible blindness. SARM1 (sterile α and TIR motif-containing protein 1) has intrinsic nicotinamide adenine dinucleotide (NAD+) hydrolase activity that causes axon degeneration by degrading axonal NAD+ significantly after activation by axon injury. SARM1 deletion is neuroprotective in many, but not all, neurodegenerative disease models. Here, we compare two therapy strategies for SARM1 inhibition, antisense oligonucleotide (ASO) and CRISPR, with germline SARM1 deletion in the neuroprotection of three optic neuropathy mouse models. This study reveals that, similar to germline SARM1 knockout in every cell, local retinal SARM1 ASO delivery and adeno-associated virus (AAV)-mediated RGC-specific CRISPR knockdown of SARM1 provide comparable neuroprotection to both RGC somata and axons in the silicone oil-induced ocular hypertension (SOHU) glaucoma model but only protect RGC axons, not somata, after traumatic ON injury. Surprisingly, neither of these two therapy strategies of SARM1 inhibition nor SARM1 germline knockout (KO) benefits RGC or ON survival in the experimental autoimmune encephalomyelitis (EAE)/optic neuritis model. Our studies therefore suggest that SARM1 inhibition by local ASO delivery or AAV-mediated CRISPR is a promising neuroprotective gene therapy strategy for traumatic and glaucomatous optic neuropathies but not for demyelinating optic neuritis.
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Affiliation(s)
- Pingting Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Wei Chen
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Haowen Jiang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Liping Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Fang Fang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Xue Feng
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Dong Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | | | - Karen Ling
- Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Jiangbin Ye
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
- Corresponding author: Yang Hu, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA.
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7
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Rangel B, Mesentier-Louro LA, Lowe LL, Shariati AM, Dalal R, Imventarza JA, Liao YJ. Upregulation of retinal VEGF and connexin 43 in murine nonarteritic anterior ischemic optic neuropathy induced with 577 nm laser. Exp Eye Res 2022; 225:109139. [PMID: 35691373 PMCID: PMC10870834 DOI: 10.1016/j.exer.2022.109139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/08/2022] [Accepted: 06/01/2022] [Indexed: 12/29/2022]
Abstract
Nonarteritic anterior ischemic optic neuropathy (NAION) is a common acute optic neuropathy and cause of irreversible vision loss in those older than 50 years of age. There is currently no effective treatment for NAION and the biological mechanisms leading to neuronal loss are not fully understood. Promising novel targets include glial cells activation and intercellular communication mediated by molecules such as gap junction protein Connexin 43 (Cx43), which modulate neuronal fate in central nervous system disorders. In this study, we investigated retinal glial changes and neuronal loss following a novel NAION animal model using a 577 nm yellow laser. We induced unilateral photochemical thrombosis using rose bengal at the optic nerve head vasculature in adult C57BL/6 mice using a 577 nm laser and performed morphometric analysis of the retinal structure using serial in vivo optical coherence tomography (OCT) and histology for glial and neuronal markers. One day after experimental NAION, in acute phase, OCT imaging revealed peripapillary thickening of the retinal ganglion cell complex (GCC, baseline: 79.5 ± 1.0 μm, n = 8; NAION: 93.0 ± 2.5 μm, n = 8, P < 0.01) and total retina (baseline: 202.9 ± 2.4 μm, n = 8; NAION: 228.1 ± 6.8 μm, n = 8, P < 0.01). Twenty-one days after ischemia, at a chronic phase, there was significant GCC thinning (baseline 78.3 ± 2.1 μm, n = 6; NAION: 72.2 ± 1.9 μm, n = 5, P < 0.05), mimicking human disease. Examination of molecular changes in the retina one day after ischemia revealed that NAION induced a significant increase in retinal VEGF levels (control: 2319 ± 195, n = 5; NAION: 4549 ± 683 gray mean value, n = 5, P < 0.05), which highly correlated with retinal thickness (r = 0.89, P < 0.05). NAION also led to significant increase in mRNA level for Cx43 (Gj1a) at day 1 (control: 1.291 ± 0.38; NAION: 3.360 ± 0.58 puncta/mm2, n = 5, P < 0.05), but not of glial fibrillary acidic protein (Gfap) at the same time (control: 2,800 ± 0.59; NAION: 4,690 ± 0.90 puncta/mm2 n = 5, P = 0.19). Retinal ganglion cell loss at day 21 was confirmed by a 30% decrease in Brn3a+ cells (control: 2,844 ± 235; NAION: 2,001 ± 264 cells/mm2, n = 4, P < 0.05). We described a novel protocol of NAION induction by photochemical thrombosis using a 577 nm laser, leading to retinal edema and VEGF increase at day 1 and RGCs loss at day 21 after injury, consistent with the pathophysiology of human NAION. Early changes in glial cells intercommunication revealed by increased Cx43+ gap junctions are consistent with a retinal glial role in mediating cell-to-cell signaling after an ischemic insult. Our study demonstrates an early glial response in a novel NAION animal model and reveals glial intercommunication molecules such as Cx43 as a promising therapeutic target in acute NAION.
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Affiliation(s)
- Barbara Rangel
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, 94303, USA
| | | | - Lauryn L Lowe
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, 94303, USA
| | - Ali Mohammad Shariati
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, 94303, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, 94303, USA
| | - Joel A Imventarza
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, 94303, USA
| | - Yaping Joyce Liao
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, 94303, USA; Department of Neurology, Stanford University School of Medicine, Stanford, CA, 94304, USA.
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8
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Liu P, Huang H, Fang F, Liu L, Li L, Feng X, Chen W, Dalal R, Sun Y, Hu Y. Neuronal NMNAT2 Overexpression Does Not Achieve Significant Neuroprotection in Experimental Autoimmune Encephalomyelitis/Optic Neuritis. Front Cell Neurosci 2021; 15:754651. [PMID: 34707482 PMCID: PMC8542903 DOI: 10.3389/fncel.2021.754651] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/10/2021] [Indexed: 11/20/2022] Open
Abstract
Optic neuritis, inflammation, and demyelination of the optic nerve (ON), is one of the most common clinical manifestations of multiple sclerosis; affected patients suffer persistent visual symptoms due to ON degeneration and secondary retinal ganglion cell (RGC) death. The mouse experimental autoimmune encephalomyelitis (EAE) model replicates optic neuritis and significant RGC soma and axon loss. Nicotinamide mononucleotide adenylyltransferases (NMNATs) are NAD+-synthetic enzymes that have been shown to be essential for axon integrity, activation of which significantly delays axonal Wallerian degeneration. NMNAT2, which is enriched in axons, has been proposed as a promising therapeutic target for axon injury-induced neurodegeneration. We therefore investigated whether activation of NMNAT2 can be used as a gene therapy strategy for neuroprotection in EAE/optic neuritis. To avoid the confounding effects in inflammatory cells, which play important roles in EAE initiation and progression, we used an RGC-specific promoter to drive the expression of the long half-life NMNAT2 mutant in mouse RGCs in vivo. However, optical coherence tomography in vivo retina imaging did not reveal significant protection of the ganglion cell complex, and visual function assays, pattern electroretinography, and optokinetic response also showed no improvement in mice with NMNAT2 overexpression. Postmortem histological analysis of retina wholemounts and semithin sections of ON confirmed the in vivo results: NMNAT2 activation in RGCs does not provide significant neuroprotection of RGCs in EAE/optic neuritis. Our studies suggest that a different degenerative mechanism than Wallerian degeneration is involved in autoimmune inflammatory axonopathy and that NMNAT2 may not be a major contributor to this mechanism.
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Affiliation(s)
- Pingting Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Fang Fang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States.,Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Liang Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Xue Feng
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Wei Chen
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
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9
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Affiliation(s)
- R Dalal
- Stockport NHS Foundation Trust, UK
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10
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Fang F, Zhang J, Zhuang P, Liu P, Li L, Huang H, Webber HC, Xu Y, Liu L, Dalal R, Sun Y, Hu Y. Chronic mild and acute severe glaucomatous neurodegeneration derived from silicone oil-induced ocular hypertension. Sci Rep 2021; 11:9052. [PMID: 33907301 PMCID: PMC8079709 DOI: 10.1038/s41598-021-88690-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 04/15/2021] [Indexed: 11/15/2022] Open
Abstract
Recently, we established silicone oil-induced ocular hypertension (SOHU) mouse model with significant glaucomatous neurodegeneration. Here we characterize two additional variations of this model that simulate two distinct glaucoma types. The first is a chronic model produced by high frequency (HF) pupillary dilation after SO-induced pupillary block, which shows sustained moderate IOP elevation and corresponding slow, mild glaucomatous neurodegeneration. We also demonstrate that although SO removal quickly returns IOP to normal, the glaucomatous neurodegeneration continues to advance to a similar degree as in the HF group without SO removal. The second, an acute model created by no pupillary dilation (ND), shows a greatly elevated IOP and severe inner retina degeneration at an early time point. Therefore, by a straightforward dilation scheme, we extend our original SOHU model to recapitulate phenotypes of two major glaucoma forms, which will be invaluable for selecting neuroprotectants and elucidating their molecular mechanisms.
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Affiliation(s)
- Fang Fang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - Jie Zhang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Pei Zhuang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Pingting Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Hannah C Webber
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Yangfan Xu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Liang Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA.
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11
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Mesentier-Louro LA, Rangel B, Stell L, Shariati MA, Dalal R, Nathan A, Yuan K, de Jesus Perez V, Liao YJ. Hypoxia-induced inflammation: Profiling the first 24-hour posthypoxic plasma and central nervous system changes. PLoS One 2021; 16:e0246681. [PMID: 33661927 PMCID: PMC7932147 DOI: 10.1371/journal.pone.0246681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/22/2021] [Indexed: 11/18/2022] Open
Abstract
Central nervous system and visual dysfunction is an unfortunate consequence of systemic hypoxia in the setting of cardiopulmonary disease, including infection with SARS-CoV-2, high-altitude cerebral edema and retinopathy and other conditions. Hypoxia-induced inflammatory signaling may lead to retinal inflammation, gliosis and visual disturbances. We investigated the consequences of systemic hypoxia using serial retinal optical coherence tomography and by assessing the earliest changes within 24h after hypoxia by measuring a proteomics panel of 39 cytokines, chemokines and growth factors in the plasma and retina, as well as using retinal histology. We induced severe systemic hypoxia in adult C57BL/6 mice using a hypoxia chamber (10% O2) for 1 week and rapidly assessed measurements within 1h compared with 18h after hypoxia. Optical coherence tomography revealed retinal tissue edema at 18h after hypoxia. Hierarchical clustering of plasma and retinal immune molecules revealed obvious segregation of the 1h posthypoxia group away from that of controls. One hour after hypoxia, there were 10 significantly increased molecules in plasma and 4 in retina. Interleukin-1β and vascular endothelial growth factor were increased in both tissues. Concomitantly, there was significantly increased aquaporin-4, decreased Kir4.1, and increased gliosis in retinal histology. In summary, the immediate posthypoxic period is characterized by molecular changes consistent with systemic and retinal inflammation and retinal glial changes important in water transport, leading to tissue edema. This posthypoxic inflammation rapidly improves within 24h, consistent with the typically mild and transient visual disturbance in hypoxia, such as in high-altitude retinopathy. Given hypoxia increases risk of vision loss, more studies in at-risk patients, such as plasma immune profiling and in vivo retinal imaging, are needed in order to identify novel diagnostic or prognostic biomarkers of visual impairment in systemic hypoxia.
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Affiliation(s)
- Louise A. Mesentier-Louro
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Barbara Rangel
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Laurel Stell
- Department of Biomedical Data Science, Stanford University, School of Medicine, Stanford, California, United States of America
| | - M. Ali Shariati
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Abinaya Nathan
- Department of Pulmonary Medicine, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Ke Yuan
- Divisions of Pulmonary Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Vinicio de Jesus Perez
- Department of Pulmonary Medicine, Stanford University, School of Medicine, Stanford, California, United States of America
| | - Yaping Joyce Liao
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, California, United States of America
- Department of Neurology, Stanford University, School of Medicine, Stanford, California, United States of America
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12
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Yaddanapudi L, Dalal R, Agnihotri SB. Positive deviance in child malnutrition of urban poor of Mumbai, India: A longitudinal analysis. Eur J Public Health 2020. [DOI: 10.1093/eurpub/ckaa166.987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Maharashtra has the largest share of urban population in India (13.5%) and is home to the largest slums. Malnutrition rates in these settlements are very high due to insufficient feeding, poverty, poor water quality and sanitation. The Foundation for Mother and Child Health (FMCH) has been working on reducing malnutrition in the urban slums of Mumbai for about 14 years now. Longitudinal data (2014-2019) collected by them was used in this analysis.
Objectives
To analyze the nutritional status of children before and after the intervention of FMCH and identify underlying factors associated with positive deviance in them.
Methods
NFHS-4 urban data of the lowest wealth quintile was used to analyze nutritional status of urban poor in India. Primary data of 4634 children (age 0-5) from the slums of Mumbai was analyzed for nutritional status during baseline and end line using ENA software. Descriptive statistical methods and binary logistic regression model were applied on selected 1583 cases using SPSS.
Results
Malnutrition rates in these children were lesser than national averages until 2 years of age. From baseline to end line, 48% reduction was observed in wasting within the first 6 months of age. Binary logistic regression reveals that age at registration (Odds ratio, OR = 0.94, p-value=0.04) and area of residence (p-value=0.00) are two most significant factors contributing to positive deviance in the child's nutritional status. Another univariate logistic regression on categorized breastfeeding score reveals that a higher score results in higher odds (OR = 1.561, p-value=0.01) of positive deviance in nutritional status of the child.
Conclusions
Since the strategy in each area is different, the most successful strategy is thus identified. The importance of early identification and intervention for effective tackling of malnutrition is highlighted through this analysis. Also, the role of effective breastfeeding techniques has emerged to be extremely significant.
Key messages
Impacting over 4000 children, the right nutrition in the first 1000 days and regular monitoring resulted in almost 50% reduction in wasting. Effective breastfeeding techniques were found to be extremely significant in the improvement of child's nutritional status.
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Affiliation(s)
- L Yaddanapudi
- Centre for Technology Alternatives for Rural Areas, Indian Institute of Technology Bombay, Mumbai, India
| | - R Dalal
- Centre for Technology Alternatives for Rural Areas, Indian Institute of Technology Bombay, Mumbai, India
| | - S B Agnihotri
- Centre for Technology Alternatives for Rural Areas, Indian Institute of Technology Bombay, Mumbai, India
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13
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Mesentier-Louro LA, Shariati MA, Dalal R, Camargo A, Kumar V, Shamskhou EA, de Jesus Perez V, Liao YJ. Systemic hypoxia led to little retinal neuronal loss and dramatic optic nerve glial response. Exp Eye Res 2020; 193:107957. [PMID: 32032627 PMCID: PMC7673281 DOI: 10.1016/j.exer.2020.107957] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/19/2019] [Accepted: 02/03/2020] [Indexed: 01/23/2023]
Abstract
Vision loss is a devastating consequence of systemic hypoxia, but the cellular mechanisms are unclear. We investigated the impact of acute hypoxia in the retina and optic nerve. We induced systemic hypoxia (10% O2) in 6-8w mice for 48 h and performed in vivo imaging using optical coherence tomography (OCT) at baseline and after 48 h to analyze structural changes in the retina and optic nerve. We analyzed glial cellular and molecular changes by histology and immunofluorescence and the impact of pretreatment with 4-phenylbutyric acid (4-PBA) in oligodendroglia survival. After 48 h hypoxia, we found no change in ganglion cell complex thickness and no loss of retinal ganglion cells. Despite this, there was significantly increased expression of CCAAT-enhancer-binding protein homologous protein (CHOP), a marker of endoplasmic reticulum stress, in the retina and optic nerve. In addition, hypoxia induced obvious increase of GFAP expression in the anterior optic nerve, where it co-localized with CHOP, and significant loss of Olig2+ oligodendrocytes. Pretreatment with 4-PBA, which has been shown to reduce endoplasmic reticulum stress, rescued total Olig2+ oligodendrocytes and increased the pool of mature (CC-1+) but not of immature (PDGFRa+) oligodendrocytes. Consistent with a selective vulnerability of the retina and optic nerve in hypoxia, the most striking changes in the 48 h murine model of hypoxia were in glial cells in the optic nerve, including increased CHOP expression in the astrocytes and loss of oligodendrocytes. Our data support a model where glial dysfunction is among the earliest events in systemic hypoxia - suggesting that glia may be a novel target in treatment of hypoxia.
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Affiliation(s)
| | - Mohammed Ali Shariati
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, CA, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, CA, USA
| | - Alexandra Camargo
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, CA, USA
| | - Varun Kumar
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, CA, USA
| | - Elya Ali Shamskhou
- Department of Pulmonary Medicine, Stanford University, School of Medicine, Stanford, CA, USA
| | - Vinicio de Jesus Perez
- Department of Pulmonary Medicine, Stanford University, School of Medicine, Stanford, CA, USA
| | - Yaping Joyce Liao
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, CA, USA; Department of Neurology, Stanford University, School of Medicine, Stanford, CA, USA.
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14
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Xia X, Atkins M, Dalal R, Kuzmenko O, Chang KC, Sun CB, Benatti CA, Rak DJ, Nahmou M, Kunzevitzky NJ, Goldberg JL. Magnetic Human Corneal Endothelial Cell Transplant: Delivery, Retention, and Short-Term Efficacy. Invest Ophthalmol Vis Sci 2019; 60:2438-2448. [PMID: 31158276 PMCID: PMC6546151 DOI: 10.1167/iovs.18-26001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Purpose Corneal endothelial dysfunction leads to corneal edema, pain, and vision loss. Adequate animal models are needed to study the safety and efficacy of novel cell therapies as an alternative to corneal transplantation. Methods Primary human corneal endothelial cells (HCECs) were isolated from cadaveric donor corneas, expanded in vitro, transduced to express green fluorescent protein (GFP), loaded with superparamagnetic nanoparticles, and injected into the anterior chamber of adult rabbits immediately after endothelial cell or Descemet's membrane stripping. The same volume of balanced salt solution plus (BSS+) was injected in control eyes. We compared different models for inducing corneal edema in rabbits, and examined the ability of transplanted HCECs to reduce corneal edema over time by measuring central corneal thickness and tracking corneal clarity. GFP-positive donor cells were tracked in vivo using optical coherence tomography (OCT) fluorescence angiography module, and the transplanted cells were confirmed by human nuclei immunostaining. Results Magnetic HCECs integrated onto the recipient corneas with intact Descemet's membrane, and donor identity was confirmed by GFP expression and immunostaining for human nuclei marker. Donor HCECs formed a monolayer on the posterior corneal surface and expressed HCEC functional markers of tight junction formation. No GFP-positive cells were observed in the trabecular meshwork or on the iris, and intraocular pressure remained stable through the length of the study. Conclusions Our results demonstrate magnetic cell-based therapy efficiently delivers HCECs to restore corneal transparency without detectable toxicity or adverse effect on intraocular pressure. Magnetic delivery of HCECs may enhance corneal function and should be explored further for human therapies.
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Affiliation(s)
- Xin Xia
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Melissa Atkins
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Roopa Dalal
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Olga Kuzmenko
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Kun-Che Chang
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Catalina B Sun
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - C Andres Benatti
- Shiley Eye Center, University of California, San Diego, La Jolla, California, United States
| | - Dillon J Rak
- Shiley Eye Center, University of California, San Diego, La Jolla, California, United States
| | - Michael Nahmou
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States
| | - Noelia J Kunzevitzky
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States.,Shiley Eye Center, University of California, San Diego, La Jolla, California, United States.,Emmecell, Menlo Park, California, United States
| | - Jeffrey L Goldberg
- Byers Eye Institute and Spencer Center for Vision Research, Department of Ophthalmology, Stanford University, Palo Alto, California, United States.,Shiley Eye Center, University of California, San Diego, La Jolla, California, United States
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15
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Kossler AL, Brinton M, Patel ZM, Dalal R, Ta CN, Palanker D. Chronic Electrical Stimulation for Tear Secretion: Lacrimal vs. anterior ethmoid nerve. Ocul Surf 2019; 17:822-827. [PMID: 31476515 DOI: 10.1016/j.jtos.2019.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/06/2019] [Accepted: 08/29/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE To evaluate and compare the effect of lacrimal nerve stimulation (LNS) and anterior ethmoid nerve stimulation (AENS) on aqueous tear secretion, and tissue condition following chronic implantation. METHODS A neurostimulator was implanted in rabbits adjacent to the (1) lacrimal nerve, and (2) anterior ethmoid nerve. Tear volume was measured with Schirmer test strips after stimulation (2.3-2.8 mA pulses at 30 Hz for 3-5 min), and scores were compared to sham stimulation. Lacrimal gland and nasal septal tissue were evaluated histologically after chronic stimulation (2 weeks-7 months). RESULTS LNS increases tear volume by 32% above sham (p < 0.05, n = 5), compared with 133% for AENS (p ≤ 0.01, n = 6). AENS also significantly increases tear secretion in the fellow, non-stimulated eye (p ≤ 0.01, n = 6), as expected from the tearing reflex pathway. Histologically, chronic LNS is well tolerated by surrounding tissues while chronic AENS results in nasal mucosal fibrosis and implant extrusion within 3 weeks. CONCLUSIONS AENS is significantly more effective than LNS at enhancing aqueous tear secretion, including the fellow eye. The lacrimal implant is well tolerated, while the nasal implant requires further design optimization to improve tolerability.
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Affiliation(s)
- Andrea L Kossler
- Department of Ophthalmology, Stanford University, Stanford, CA, USA.
| | - Mark Brinton
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
| | - Zara M Patel
- Department of Otolaryngology, Stanford University, Stanford, CA, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Christopher N Ta
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Daniel Palanker
- Department of Ophthalmology, Stanford University, Stanford, CA, USA; Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
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16
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Kang S, Lorach H, Bhuckory MB, Quan Y, Dalal R, Palanker D. Retinal Laser Therapy Preserves Photoreceptors in a Rodent Model of MERTK-Related Retinitis Pigmentosa. Transl Vis Sci Technol 2019; 8:19. [PMID: 31402999 PMCID: PMC6685484 DOI: 10.1167/tvst.8.4.19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/07/2019] [Indexed: 01/14/2023] Open
Abstract
Purpose We investigated the effects of various retinal laser therapies on preservation of the photoreceptors in an animal model of Mer tyrosine kinase receptor (MERTK)-related retinitis pigmentosa (RP). These modalities included photocoagulation with various pattern densities, selective RPE therapy (SRT), and nondamaging retinal therapy (NRT). Methods Laser treatments were performed on right eyes of RCS rats, using one of three laser modalities. For photocoagulation, six pattern densities (spot spacings of 0.5, 1, 1.5, 3, 4, and 5 spot diameters) were delivered in 19-day-old animals, prior to the onset of photoreceptor degeneration, to determine the optimal treatment density for the best preservation of photoreceptors. The left eye was used as control. Rats were monitored for 6 months after treatment using electroretinography, optical coherence tomography, and histology. Results Photocoagulation resulted in long-term preservation of photoreceptors, manifested morphologically and functionally, with the extent of the benefit dependent on the laser pattern density. Eyes treated with a 1.5 spot size spacing showed the best morphologic and functional preservation during the 6-month follow-up. SRT-treated eyes exhibited short-term morphologic preservation, but no functional benefit. NRT-treated eyes did not show any observable preservation benefit from the treatment. Conclusions In a rodent model of MERTK-related RP, pattern photocoagulation of about 15% of the photoreceptors (1.5 spot diameter spacing) provides long-term preservation of photoreceptors in the treatment area. Translational Relevance Availability of retinal lasers in ophthalmic practice enables rapid translation of our study to clinical testing and may help preserve the sight in patients with photoreceptor degeneration.
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Affiliation(s)
- Seungbum Kang
- Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Henri Lorach
- Hansen Experimental Physics Laboratory, Stanford University, CA, USA.,Department of Ophthalmology, Stanford University, CA, USA
| | - Mohajeet B Bhuckory
- Hansen Experimental Physics Laboratory, Stanford University, CA, USA.,Department of Ophthalmology, Stanford University, CA, USA
| | - Yi Quan
- Department of Ophthalmology, Stanford University, CA, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, CA, USA
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, CA, USA.,Department of Ophthalmology, Stanford University, CA, USA
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17
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Flores T, Huang T, Bhuckory M, Ho E, Chen Z, Dalal R, Galambos L, Kamins T, Mathieson K, Palanker D. Honeycomb-shaped electro-neural interface enables cellular-scale pixels in subretinal prosthesis. Sci Rep 2019; 9:10657. [PMID: 31337815 PMCID: PMC6650428 DOI: 10.1038/s41598-019-47082-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 07/10/2019] [Indexed: 11/08/2022] Open
Abstract
High-resolution visual prostheses require small, densely packed pixels, but limited penetration depth of the electric field formed by a planar electrode array constrains such miniaturization. We present a novel honeycomb configuration of an electrode array with vertically separated active and return electrodes designed to leverage migration of retinal cells into voids in the subretinal space. Insulating walls surrounding each pixel decouple the field penetration depth from the pixel width by aligning the electric field vertically, enabling a decrease of the pixel size down to cellular dimensions. We demonstrate that inner retinal cells migrate into the 25 μm deep honeycomb wells as narrow as 18 μm, resulting in more than half of these cells residing within the electrode cavities. Immune response to honeycombs is comparable to that with planar arrays. Modeled stimulation threshold current density with honeycombs does not increase substantially with reduced pixel size, unlike quadratic increase with planar arrays. This 3-D electrode configuration may enable functional restoration of central vision with acuity better than 20/100 for millions of patients suffering from age-related macular degeneration.
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Affiliation(s)
- Thomas Flores
- Department of Applied Physics, Stanford University, Stanford, CA, USA.
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA.
| | - Tiffany Huang
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Mohajeet Bhuckory
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Elton Ho
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Zhijie Chen
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Ludwig Galambos
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Theodore Kamins
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Keith Mathieson
- Institute of Photonics, University of Strathclyde, Glasgow, Scotland, UK
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
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18
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Lorach H, Kang S, Bhuckory MB, Trouillet A, Dalal R, Marmor M, Palanker D. Transplantation of Mature Photoreceptors in Rodents With Retinal Degeneration. Transl Vis Sci Technol 2019; 8:30. [PMID: 31171997 PMCID: PMC6543858 DOI: 10.1167/tvst.8.3.30] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 04/01/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose To demonstrate survival and integration of mature photoreceptors transplanted with the retinal pigment epithelium (RPE). Methods Full-thickness retina with attached RPE was harvested from healthy adult rats. Grafts were implanted into two rat models of retinal degeneration, Royal College of Surgeons (RCS) and S334ter-3. Survival of the host and transplanted retina was monitored using optical coherence tomography (OCT) for up to 6 months. The retinal structure and synaptogenesis between the host and transplant was assessed by histology and immunohistochemistry. Results OCT and histology demonstrated a well-preserved photoreceptor layer with inner and outer segments, while the inner retinal layers of the transplant largely disappeared. Grafts, including RPE, survived better than without and the transplanted RPE appeared as a monolayer integrated with the native one. Synaptogenesis was observed through sprouting of new dendrites from the host bipolar cells and synaptic connections forming with cells of the transplant. However, in many samples, a glial fibrillary acidic protein–positive membrane separated the host retina and the graft. Conclusions Presence of RPE in the graft improved the survival of transplanted photoreceptors. Functional integration between the transplant and the host retina is likely to be further enhanced if formation of a glial seal could be prevented. Transplantation of the mature photoreceptors with RPE may be a practical approach to restoration of sight in retinal degeneration. Translational Relevance This approach to restoration of sight in patients with photoreceptor degeneration can be rapidly advanced to clinical testing. In patients with central scotoma, autologous transplantation of the peripheral retina can be an option.
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Affiliation(s)
- Henri Lorach
- Hansen Experimental Physics Laboratory, Stanford University, CA, USA
| | - Seungbum Kang
- Hansen Experimental Physics Laboratory, Stanford University, CA, USA.,Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Mohajeet B Bhuckory
- Hansen Experimental Physics Laboratory, Stanford University, CA, USA.,Department of Ophthalmology, Stanford University, CA, USA
| | - Alix Trouillet
- Department of Otolaryngology, Stanford University, CA, USA
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, CA, USA
| | - Michael Marmor
- Department of Ophthalmology, Stanford University, CA, USA
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, CA, USA.,Department of Ophthalmology, Stanford University, CA, USA
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19
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Zhang J, Li L, Huang H, Fang F, Webber HC, Zhuang P, Liu L, Dalal R, Tang PH, Mahajan VB, Sun Y, Li S, Zhang M, Goldberg JL, Hu Y. Silicone oil-induced ocular hypertension and glaucomatous neurodegeneration in mouse. eLife 2019; 8:45881. [PMID: 31090540 PMCID: PMC6533060 DOI: 10.7554/elife.45881] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/14/2019] [Indexed: 02/06/2023] Open
Abstract
Understanding the molecular mechanism of glaucoma and development of neuroprotectants is significantly hindered by the lack of a reliable animal model that accurately recapitulates human glaucoma. Here, we sought to develop a mouse model for the secondary glaucoma that is often observed in humans after silicone oil (SO) blocks the pupil or migrates into the anterior chamber following vitreoretinal surgery. We observed significant intraocular pressure (IOP) elevation after intracameral injection of SO, and that SO removal allows IOP to return quickly to normal. This simple, inducible and reversible mouse ocular hypertension model shows dynamic changes of visual function that correlate with progressive retinal ganglion cell (RGC) loss and axon degeneration. It may be applicable with only minor modifications to a range of animal species in which it will generate stable, robust IOP elevation and significant neurodegeneration that will facilitate selection of neuroprotectants and investigating the pathogenesis of ocular hypertension-induced glaucoma.
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Affiliation(s)
- Jie Zhang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Tongji Medical College, Union Hospital, Huazhong University of Science & Technology, Wuhan, China
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Fang Fang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hannah C Webber
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Pei Zhuang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Liang Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Peter H Tang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Veterans Affairs Palo Alto Health Care, Palo Alto, United States
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Veterans Affairs Palo Alto Health Care, Palo Alto, United States
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Veterans Affairs Palo Alto Health Care, Palo Alto, United States
| | - Shaohua Li
- Department of Ophthalmology, Tongji Medical College, Union Hospital, Huazhong University of Science & Technology, Wuhan, China
| | - Mingchang Zhang
- Department of Ophthalmology, Tongji Medical College, Union Hospital, Huazhong University of Science & Technology, Wuhan, China
| | - Jeffrey L Goldberg
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
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Yoshino T, Siena S, Dalal R, Okuda Y, Yamamoto E, Grothey A. A multicenter, multicohort, phase II study of trastuzumab deruxtecan (DS-8201a) in subjects with HER2-expressing metastatic colorectal cancer. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy431.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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21
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Shitara K, Bang YJ, Sakai D, Yasui H, Kawaguchi Y, Sugihara M, Saito K, Dalal R, Yamaguchi K. A randomized, phase II, multicenter, open-label study of trastuzumab deruxtecan (DS-8201a) in subjects with HER2-expressing gastric cancer. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy432.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Lorach H, Kang S, Dalal R, Bhuckory MB, Quan Y, Palanker D. Long-term Rescue of Photoreceptors in a Rodent Model of Retinitis Pigmentosa Associated with MERTK Mutation. Sci Rep 2018; 8:11312. [PMID: 30054542 PMCID: PMC6063887 DOI: 10.1038/s41598-018-29631-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 07/13/2018] [Indexed: 02/07/2023] Open
Abstract
MERTK mutation reduces the ability of retinal pigment epithelial (RPE) cells to phagocytize the photoreceptor outer segments, which leads to accumulation of debris separating photoreceptors from RPE cells, resulting in their degeneration and loss of vision. In a rat model of Retinitis Pigmentosa due to MERTK mutation, we demonstrate that surgical removal of debris performed when about half of photoreceptors are lost (P38), allows the remaining photoreceptor cells to renew their outer segments and survive for at least 6 months - 3 times longer than in untreated eyes. In another set of experiments, patterned laser photocoagulation was performed before the debris formation (P19-25) to destroy a fraction of photoreceptors and thereby reduce the phagocytic load of shed outer segment fragments. This treatment also delayed the degeneration of the remaining photoreceptors. Both approaches were assessed functionally and morphologically, using electroretinography, optical coherence tomography, and histology. The long-term preservation of photoreceptors we observed indicates that MERTK-related form of inherited retinal degeneration, which has currently no cure, could be amenable to laser therapy or subretinal surgery, to extend the visual function, potentially for life.
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Affiliation(s)
- H Lorach
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA.
| | - S Kang
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
- Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - R Dalal
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - M B Bhuckory
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - Y Quan
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
| | - D Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, USA
- Department of Ophthalmology, Stanford University, Stanford, CA, USA
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Yoshino T, Siena S, Dalal R, Okuda Y, Yamamoto E, Grothey A. A multicenter, multicohort, phase 2 study of trastuzumab deruxtecan (DS-8201a) in subjects with HER2-expressing metastatic colorectal cancer - Trial in progress. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy151.294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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24
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Flores T, Lei X, Huang T, Lorach H, Dalal R, Galambos L, Kamins T, Mathieson K, Palanker D. Optimization of pillar electrodes in subretinal prosthesis for enhanced proximity to target neurons. J Neural Eng 2018; 15:036011. [PMID: 29388561 DOI: 10.1088/1741-2552/aaac39] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE High-resolution prosthetic vision requires dense stimulating arrays with small electrodes. However, such miniaturization reduces electrode capacitance and penetration of electric field into tissue. We evaluate potential solutions to these problems with subretinal implants based on utilization of pillar electrodes. APPROACH To study integration of three-dimensional (3D) implants with retinal tissue, we fabricated arrays with varying pillar diameter, pitch, and height, and implanted beneath the degenerate retina in rats (Royal College of Surgeons, RCS). Tissue integration was evaluated six weeks post-op using histology and whole-mount confocal fluorescence imaging. The electric field generated by various electrode configurations was calculated in COMSOL, and stimulation thresholds assessed using a model of network-mediated retinal response. MAIN RESULTS Retinal tissue migrated into the space between pillars with no visible gliosis in 90% of implanted arrays. Pillars with 10 μm height reached the middle of the inner nuclear layer (INL), while 22 μm pillars reached the upper portion of the INL. Electroplated pillars with dome-shaped caps increase the active electrode surface area. Selective deposition of sputtered iridium oxide onto the cap ensures localization of the current injection to the pillar top, obviating the need to insulate the pillar sidewall. According to computational model, pillars having a cathodic return electrode above the INL and active anodic ring electrode at the surface of the implant would enable six times lower stimulation threshold, compared to planar arrays with circumferential return, but suffer from greater cross-talk between the neighboring pixels. SIGNIFICANCE 3D electrodes in subretinal prostheses help reduce electrode-tissue separation and decrease stimulation thresholds to enable smaller pixels, and thereby improve visual acuity of prosthetic vision.
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Affiliation(s)
- Thomas Flores
- Department of Applied Physics, Stanford University, Stanford, CA, United States of America
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25
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Wang J, Quan Y, Dalal R, Palanker D. Comparison of Continuous-Wave and Micropulse Modulation in Retinal Laser Therapy. Invest Ophthalmol Vis Sci 2017; 58:4722-4732. [PMID: 28910825 DOI: 10.1167/iovs.17-21610] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Recent progress in retinal laser therapy has centered upon using thermal stress below damage threshold or selective destruction of targeted tissue layers as a stimulus for retinal repair. Temporal modulation, including micropulse, is thought to increase the selectivity of laser treatment, but has not been carefully analyzed. We measure and model the tissue response to continuous-wave (CW) and micropulse laser to evaluate the advantages and drawbacks of temporal modulation. Methods Thresholds of ophthalmoscopic visibility, which indicates damage to photoreceptors, and fluorescein angiography (FA), indicating damage to retinal pigment epithelium (RPE), were measured with 577-nm laser in rabbits for duty cycles ranging from 3% to 100% (CW) and pulse envelopes of 20 and 200 ms. Heat shock protein (HSP) expression was measured in rats. Thresholds were compared to a computational model of tissue response based on the Arrhenius integral. Results Damage to photoreceptors was defined by average power, regardless of the duty cycle, as predicted by the model. The average power for FA threshold was lower with 5% duty cycle than with CW laser by 22 ± 15% for 200-ms and 35 ± 21.5% for 20-ms envelopes, demonstrating some heat localization to RPE. The ratio of RPE damage threshold to HSP expression threshold was 1.30 ± 0.15 and 1.39 ± 0.11 for 20 ms at 5% duty cycle and CW, respectively. Conclusions Micropulse modulation with sufficiently short envelope and duty cycle can help reduce the spread of heat from the light-absorbing RPE and choroid. However, this localization does not benefit nondamaging retinal laser therapy, which is intended to avoid any cell death.
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Affiliation(s)
- Jenny Wang
- Department of Applied Physics, Stanford University, Stanford, California, United States
| | - Yi Quan
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Daniel Palanker
- Department of Ophthalmology, Stanford University, Stanford, California, United States.,Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States
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Wainberg Z, Jalal S, Muro K, Yoon H, Garrido M, Golan T, Doi T, Catenacci D, Geva R, Ku G, Bleeker J, Bang YJ, Hara H, Chung H, Savage M, Wang J, Koshiji M, Dalal R, Fuchs C. KEYNOTE-059 Update: Efficacy and safety of pembrolizumab alone or in combination with chemotherapy in patients with advanced gastric or gastroesophageal (G/GEJ) cancer. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx440.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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27
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Si P, Sen D, Dutta R, Yousefi S, Dalal R, Winetraub Y, Liba O, de la Zerda A. In Vivo Molecular Optical Coherence Tomography of Lymphatic Vessel Endothelial Hyaluronan Receptors. Sci Rep 2017; 7:1086. [PMID: 28439123 PMCID: PMC5430649 DOI: 10.1038/s41598-017-01172-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/22/2017] [Indexed: 01/29/2023] Open
Abstract
Optical Coherence Tomography (OCT) imaging of living subjects offers increased depth of penetration while maintaining high spatial resolution when compared to other optical microscopy techniques. However, since most protein biomarkers do not exhibit inherent contrast detectable by OCT, exogenous contrast agents must be employed for imaging specific cellular biomarkers of interest. While a number of OCT contrast agents have been previously studied, demonstrations of molecular targeting with such agents in live animals have been historically challenging and notably limited in success. Here we demonstrate for the first time that microbeads (µBs) can be used as contrast agents to target cellular biomarkers in lymphatic vessels and can be detected by OCT using a phase variance algorithm. This molecular OCT method enables in vivo imaging of the expression profiles of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), a biomarker that plays crucial roles in inflammation and tumor metastasis. In vivo OCT imaging of LVYE-1 showed that the biomarker was significantly down-regulated during inflammation induced by acute contact hypersensitivity (CHS). Our work demonstrated a powerful molecular imaging tool that can be used for high resolution studies of lymphatic function and dynamics in models of inflammation, tumor development, and other lymphatic diseases.
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Affiliation(s)
- Peng Si
- Molecular Imaging Program at Stanford, Stanford, California, 94305, USA.,Department of Structural Biology, 299 Campus Drive West, Stanford, California, 94305, USA
| | - Debasish Sen
- Molecular Imaging Program at Stanford, Stanford, California, 94305, USA.,Department of Structural Biology, 299 Campus Drive West, Stanford, California, 94305, USA
| | - Rebecca Dutta
- Molecular Imaging Program at Stanford, Stanford, California, 94305, USA.,Department of Structural Biology, 299 Campus Drive West, Stanford, California, 94305, USA
| | - Siavash Yousefi
- Molecular Imaging Program at Stanford, Stanford, California, 94305, USA.,Department of Radiation Oncology, 875 Blake Wilbur Drive, Stanford, California, 94305, USA
| | - Roopa Dalal
- Department of Ophthalmology, 2452 Watson Ct, Stanford, California, 94303, USA
| | - Yonatan Winetraub
- Molecular Imaging Program at Stanford, Stanford, California, 94305, USA.,Department of Structural Biology, 299 Campus Drive West, Stanford, California, 94305, USA.,Bio-X Program, Stanford University, Stanford, California, 94305, USA
| | - Orly Liba
- Molecular Imaging Program at Stanford, Stanford, California, 94305, USA.,Department of Structural Biology, 299 Campus Drive West, Stanford, California, 94305, USA.,Department of Electrical Engineering, 350 Serra Mall, Stanford, California, 94305, USA.,Bio-X Program, Stanford University, Stanford, California, 94305, USA
| | - Adam de la Zerda
- Molecular Imaging Program at Stanford, Stanford, California, 94305, USA. .,Department of Structural Biology, 299 Campus Drive West, Stanford, California, 94305, USA. .,Department of Electrical Engineering, 350 Serra Mall, Stanford, California, 94305, USA. .,Bio-X Program, Stanford University, Stanford, California, 94305, USA.
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Reck M, Garon EB, Juan O, Nadal E, Lee P, Dalal R, Liu J, He S, Treat JA, Nakagawa K. Multizentrische, randomisierte Doppelblindstudie mit Erlotinib plus Ramucirumab oder plus Plazebo bei metastasiertem nichtkleinzelligen Lungenkarzinom (NCSLC) mit EGFR-Mutation. Pneumologie 2017. [DOI: 10.1055/s-0037-1598342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- M Reck
- Lungenclinic Großhansdorf, Airway Research Center North (Arcn), Member of the German Center for Lung Research (Dzl)
| | - EB Garon
- Ucla Medical Center, Santa Monica, Ca
| | - O Juan
- Hospital Universitario La Fe, Valencia
| | - E Nadal
- Institut Catala D'oncologia, L'hospitalet, Barcelona
| | - P Lee
- Eli Lilly and Company, Bridgewater
| | - R Dalal
- Ex-Employee, Eli Lilly and Company, Bridgewater
| | - J Liu
- Eli Lilly and Company, Indianapolis
| | - S He
- Eli Lilly and Company, Indianapolis
| | - JA Treat
- Eli Lilly and Company, Indianapolis
| | - K Nakagawa
- Kinki University School of Medicine, Osaka
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SoRelle ED, Liba O, Campbell JL, Dalal R, Zavaleta CL, de la Zerda A. A hyperspectral method to assay the microphysiological fates of nanomaterials in histological samples. eLife 2016; 5. [PMID: 27536877 PMCID: PMC5042654 DOI: 10.7554/elife.16352] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/16/2016] [Indexed: 12/11/2022] Open
Abstract
Nanoparticles are used extensively as biomedical imaging probes and potential therapeutic agents. As new particles are developed and tested in vivo, it is critical to characterize their biodistribution profiles. We demonstrate a new method that uses adaptive algorithms for the analysis of hyperspectral dark-field images to study the interactions between tissues and administered nanoparticles. This non-destructive technique quantitatively identifies particles in ex vivo tissue sections and enables detailed observations of accumulation patterns arising from organ-specific clearance mechanisms, particle size, and the molecular specificity of nanoparticle surface coatings. Unlike nanoparticle uptake studies with electron microscopy, this method is tractable for imaging large fields of view. Adaptive hyperspectral image analysis achieves excellent detection sensitivity and specificity and is capable of identifying single nanoparticles. Using this method, we collected the first data on the sub-organ distribution of several types of gold nanoparticles in mice and observed localization patterns in tumors. DOI:http://dx.doi.org/10.7554/eLife.16352.001 Metallic elements like gold and silver can be made into particles that are one thousand times smaller than the width of a human hair. Researchers can create these “nanoparticles” in different sizes and shapes that exhibit unique properties. For example, gold can be made into rod-shaped particles that interact with infrared light. Other nanoparticles can be loaded with drug molecules and designed to bind to cancer cells. As a result, nanoparticles have been explored for use in a variety of biomedical imaging and therapy applications. However, we must fully understand how the nanoparticles bind to the cancer cells and how the body tolerates these nanoparticles before they can be used in humans. Experiments that explore where nanoparticles accumulate in the body are typically called biodistribution studies. However, current techniques for studying biodistribution cannot simultaneously measure the uptake of particles into organs and reveal the fine structures inside the organs that interact with the particles. SoRelle, Liba et al. aimed to address this problem by developing a new biodistribution technique called HSM-AD (short for hyperspectral microscopy with adaptive detection). This new technique combines a relatively recent method called hyperspectral dark-field microscopy, which can identify nanoparticles from their unique optical signatures, with versatile computer algorithms to detect nanoparticles. HSM-AD is more sensitive than previously developed biodistribution techniques, and SoRelle, Liba et al. used it to produce highly detailed maps of nanoparticle uptake patterns in the organs of mice. These maps provide new insights into how cells and tissues in the body handle different nanoparticles. Moreover, HSM-AD was able to distinguish nanoparticles with unique shapes by their distinct optical signatures. Further experiments show that HSM-AD can reveal interactions between human tumor cells and nanoparticles specifically designed to target those cells. HSM-AD will be a useful resource for researchers studying the effect of nanoparticles on the human body. Future studies will use this technique to explore which nanoparticles have the potential to be developed for medical uses. DOI:http://dx.doi.org/10.7554/eLife.16352.002
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Affiliation(s)
- Elliott D SoRelle
- Molecular Imaging Program at Stanford, Stanford University, Stanford, United States.,Bio-X Program, Stanford University, Stanford, United States.,Biophysics Program, Stanford University, Stanford, United States.,Department of Structural Biology, Stanford University, Stanford, United States
| | - Orly Liba
- Molecular Imaging Program at Stanford, Stanford University, Stanford, United States.,Bio-X Program, Stanford University, Stanford, United States.,Department of Structural Biology, Stanford University, Stanford, United States.,Department of Electrical Engineering, Stanford University, Stanford, United States
| | - Jos L Campbell
- Molecular Imaging Program at Stanford, Stanford University, Stanford, United States.,Department of Radiology, Stanford University, Stanford, United States
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, United States
| | - Cristina L Zavaleta
- Molecular Imaging Program at Stanford, Stanford University, Stanford, United States.,Department of Radiology, Stanford University, Stanford, United States
| | - Adam de la Zerda
- Molecular Imaging Program at Stanford, Stanford University, Stanford, United States.,Bio-X Program, Stanford University, Stanford, United States.,Biophysics Program, Stanford University, Stanford, United States.,Department of Structural Biology, Stanford University, Stanford, United States.,Department of Electrical Engineering, Stanford University, Stanford, United States
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Sen D, SoRelle ED, Liba O, Dalal R, Paulus YM, Kim TW, Moshfeghi DM, de la Zerda A. High-resolution contrast-enhanced optical coherence tomography in mice retinae. J Biomed Opt 2016; 21:66002. [PMID: 27264492 PMCID: PMC4893203 DOI: 10.1117/1.jbo.21.6.066002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 05/02/2016] [Indexed: 05/14/2023]
Abstract
Optical coherence tomography (OCT) is a noninvasive interferometric imaging modality providing anatomical information at depths of millimeters and a resolution of micrometers. Conventional OCT images limit our knowledge to anatomical structures alone, without any contrast enhancement. Therefore, here we have, for the first time, optimized an OCT-based contrast-enhanced imaging system for imaging single cells and blood vessels in vivo inside the living mouse retina at subnanomolar sensitivity. We used bioconjugated gold nanorods (GNRs) as exogenous OCT contrast agents. Specifically, we used anti-mouse CD45 coated GNRs to label mouse leukocytes and mPEG-coated GNRs to determine sensitivity of GNR detection in vivo inside mice retinae. We corroborated OCT observations with hyperspectral dark-field microscopy of formalin-fixed histological sections. Our results show that mouse leukocytes that otherwise do not produce OCT contrast can be labeled with GNRs leading to significant OCT intensity equivalent to a 0.5 nM GNR solution. Furthermore, GNRs injected intravenously can be detected inside retinal blood vessels at a sensitivity of ∼0.5 nM, and GNR-labeled cells injected intravenously can be detected inside retinal capillaries by enhanced OCT contrast. We envision the unprecedented resolution and sensitivity of functionalized GNRs coupled with OCT to be adopted for longitudinal studies of retinal disorders.
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Affiliation(s)
- Debasish Sen
- Stanford University, Department of Structural Biology, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Molecular Imaging Program at Stanford, 299 Campus Drive, Stanford, California 94305, United States
| | - Elliott D. SoRelle
- Stanford University, Department of Structural Biology, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Biophysics Program, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Department of Electrical Engineering, 299 Campus Drive, Stanford, California 94305, United States
| | - Orly Liba
- Stanford University, Department of Structural Biology, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Molecular Imaging Program at Stanford, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Department of Electrical Engineering, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Bio-X Program, 299 Campus Drive, Stanford, California, 94305, United States
| | - Roopa Dalal
- Stanford University, Department of Ophthalmology, 300 Pasteur Drive, Palo Alto, California 94304, United States
| | - Yannis M. Paulus
- Stanford University, Department of Structural Biology, 299 Campus Drive, Stanford, California 94305, United States
| | - Tae-Wan Kim
- Stanford University, Department of Structural Biology, 299 Campus Drive, Stanford, California 94305, United States
| | - Darius M. Moshfeghi
- Stanford University, Bio-X Program, 299 Campus Drive, Stanford, California, 94305, United States
- Stanford University, Department of Ophthalmology, Stanford Byers Eye Institute, 2452 Watson Court, Palo Alto, California 94303, United States
| | - Adam de la Zerda
- Stanford University, Department of Structural Biology, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Molecular Imaging Program at Stanford, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Biophysics Program, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Department of Electrical Engineering, 299 Campus Drive, Stanford, California 94305, United States
- Stanford University, Bio-X Program, 299 Campus Drive, Stanford, California, 94305, United States
- Address all correspondence to: Adam de la Zerda, E-mail:
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31
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Lavinsky D, Wang J, Huie P, Dalal R, Lee SJ, Lee DY, Palanker D. Nondamaging Retinal Laser Therapy: Rationale and Applications to the Macula. Invest Ophthalmol Vis Sci 2016; 57:2488-500. [PMID: 27159441 PMCID: PMC5995023 DOI: 10.1167/iovs.15-18981] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/25/2016] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Retinal photocoagulation and nondamaging laser therapy are used for treatment of macular disorders, without understanding of the response mechanism and with no rationale for dosimetry. To establish a proper titration algorithm, we measured the range of tissue response and damage threshold. We then evaluated safety and efficacy of nondamaging retinal therapy (NRT) based on this algorithm for chronic central serous chorioretinopathy (CSCR) and macular telangiectasia (MacTel). METHODS Retinal response to laser treatment below damage threshold was assessed in pigmented rabbits by expression of the heat shock protein HSP70 and glial fibrillary acidic protein (GFAP). Energy was adjusted relative to visible titration using the Endpoint Management (EpM) algorithm. In clinical studies, 21 eyes with CSCR and 10 eyes with MacTel were treated at 30% EpM energy with high spot density (0.25-diameter spacing). Visual acuity, retinal and choroidal thickness, and subretinal fluid were monitored for 1 year. RESULTS At 25% EpM energy and higher, HSP70 was expressed acutely in RPE, and GFAP upregulation in Müller cells was observed at 1 month. Damage appeared starting at 40% setting. Subretinal fluid resolved completely in 81% and partially in 19% of the CSCR patients, and visual acuity improved by 12 ± 3 letters. Lacunae in the majority of MacTel patients decreased while preserving the retinal thickness, and vision improved by 10 letters. CONCLUSIONS Heat shock protein expression in response to hyperthermia helps define the therapeutic window for NRT. Lack of tissue damage enables high-density treatment to boost clinical efficacy, therapy in the fovea, and retreatments to manage chronic diseases.
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Affiliation(s)
- Daniel Lavinsky
- Department of Ophthalmology, Federal University Rio Grande do Sul, Porto Alegre, Brazil
| | - Jenny Wang
- Department of Applied Physics, Stanford University, Stanford, California, United States
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States
| | - Philip Huie
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Seung Jun Lee
- Department of Ophthalmology, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Kangwon National University, Chuncheon, South Korea
| | - Dae Yeong Lee
- Department of Ophthalmology, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Gachon University Gil Medical Center, Incheon, South Korea
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Stanford University, Stanford, California, United States
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Lorach H, Lei X, Galambos L, Kamins T, Mathieson K, Dalal R, Huie P, Harris J, Palanker D. Interactions of Prosthetic and Natural Vision in Animals With Local Retinal Degeneration. Invest Ophthalmol Vis Sci 2016; 56:7444-50. [PMID: 26618643 DOI: 10.1167/iovs.15-17521] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE Prosthetic restoration of partial sensory loss leads to interactions between artificial and natural inputs. Ideally, the rehabilitation should allow perceptual fusion of the two modalities. Here we studied the interactions between normal and prosthetic vision in a rodent model of local retinal degeneration. METHODS Implantation of a photovoltaic array in the subretinal space of normally sighted rats induced local degeneration of the photoreceptors above the chip, and the inner retinal neurons in this area were electrically stimulated by the photovoltaic implant powered by near-infrared (NIR) light. We studied prosthetic and natural visually evoked potentials (VEP) in response to simultaneous stimulation by NIR and visible light patterns. RESULTS We demonstrate that electrical and natural VEPs summed linearly in the visual cortex, and both responses decreased under brighter ambient light. Responses to visible light flashes increased over 3 orders of magnitude of contrast (flash/background), while for electrical stimulation the contrast range was limited to 1 order of magnitude. The maximum amplitude of the prosthetic VEP was three times lower than the maximum response to a visible flash over the same area on the retina. CONCLUSIONS Ambient light affects prosthetic responses, albeit much less than responses to visible stimuli. Prosthetic representation of contrast in the visual scene can be encoded, to a limited extent, by the appropriately calibrated stimulus intensity, which also depends on the ambient light conditions. Such calibration will be important for patients combining central prosthetic vision with natural peripheral sight, such as in age-related macular degeneration.
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Affiliation(s)
- Henri Lorach
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Xin Lei
- Department of Electrical Engineering, Stanford University, Stanford, California, United States
| | - Ludwig Galambos
- Department of Electrical Engineering, Stanford University, Stanford, California, United States
| | - Theodore Kamins
- Department of Electrical Engineering, Stanford University, Stanford, California, United States
| | - Keith Mathieson
- Institute of Photonics, University of Strathclyde, Glasgow, Scotland, United Kingdom
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Philip Huie
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - James Harris
- Department of Electrical Engineering, Stanford University, Stanford, California, United States
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
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Lorach H, Wang J, Lee DY, Dalal R, Huie P, Palanker D. Retinal safety of near infrared radiation in photovoltaic restoration of sight. Biomed Opt Express 2016; 7:13-21. [PMID: 26819813 PMCID: PMC4722897 DOI: 10.1364/boe.7.000013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 05/25/2023]
Abstract
Photovoltaic restoration of sight requires intense near-infrared light to effectively stimulate retinal neurons. We assess the retinal safety of such radiation with and without the retinal implant. Retinal damage threshold was determined in pigmented rabbits exposed to 880nm laser radiation. The 50% probability (ED50) of retinal damage during 100s exposures with 1.2mm diameter beam occurred at 175mW, corresponding to a modeled temperature rise of 12.5°C. With the implant, the same temperature was reached at 78mW, close to the experimental ED50 of 71mW. In typical use conditions, the retinal temperature rise is not expected to exceed 0.43°C, well within the safety limits for chronic use.
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Affiliation(s)
- H. Lorach
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - J. Wang
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - D. Y. Lee
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Gachon University, Gil Medical Center, Incheon, 21565, South Korea
| | - R. Dalal
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - P. Huie
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - D. Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
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Lorach H, Kung J, Beier C, Mandel Y, Dalal R, Huie P, Wang J, Lee S, Sher A, Jones BW, Palanker D. Development of Animal Models of Local Retinal Degeneration. Invest Ophthalmol Vis Sci 2015. [PMID: 26207299 DOI: 10.1167/iovs.14-16011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Development of nongenetic animal models of local retinal degeneration is essential for studies of retinal pathologies, such as chronic retinal detachment or age-related macular degeneration. We present two different methods to induce a highly localized retinal degeneration with precise onset time, that can be applied to a broad range of species in laboratory use. METHODS A 30-μm thin polymer sheet was implanted subretinally in wild-type (WT) rats. The effects of chronic retinal separation from the RPE were studied using histology and immunohistochemistry. Another approach is applicable to species with avascular retina, such as rabbits, where the photoreceptors and RPE were thermally ablated over large areas, using a high power scanning laser. RESULTS Photoreceptors above the subretinal implant in rats degenerated over time, with 80% of the outer nuclear layer disappearing within a month, and the rest by 3 months. Similar loss was obtained by selective photocoagulation with a scanning laser. Cells in the inner nuclear layer and ganglion cell layer were preserved in both cases. However, there were signs of rewiring and decrease in the size of the bipolar cell terminals in the damaged areas. CONCLUSIONS Both methods induce highly reproducible degeneration of photoreceptors over a defined area, with complete preservation of the inner retinal neurons during the 3-month follow-up. They provide a reliable platform for studies of local retinal degeneration and development of therapeutic strategies in a wide variety of species.
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Affiliation(s)
- Henri Lorach
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States 3Institut de la Vision, Paris, France
| | - Jennifer Kung
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Corinne Beier
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California, United States
| | - Yossi Mandel
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 5Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Philip Huie
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Jenny Wang
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Seungjun Lee
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Alexander Sher
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California, United States
| | - Bryan William Jones
- Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States 2Department of Ophthalmology, Stanford University, Stanford, California, United States
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Wang J, Chung JL, Schuele G, Vankov A, Dalal R, Wiltberger M, Palanker D. Safety of cornea and iris in ocular surgery with 355-nm lasers. J Biomed Opt 2015; 20:095005. [PMID: 26359809 DOI: 10.1117/1.jbo.20.9.095005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/03/2015] [Indexed: 06/05/2023]
Abstract
A recent study showed that 355-nm nanosecond lasers cut cornea with similar precision to infrared femtosecond lasers. However, use of ultraviolet wavelength requires precise assessment of ocular safety to determine the range of possible ophthalmic applications. In this study, the 355-nm nanosecond laser was evaluated for corneal and iris damage in rabbit, porcine, and human donor eyes as determined by minimum visible lesion (MVL) observation, live/dead staining of the endothelium, and apoptosis assay. Single-pulse damage to the iris was evaluated on porcine eyes using live/dead staining. In live rabbits, the cumulative median effective dose (ED50) for corneal damage was 231 J/cm2, as seen by lesion observation. Appearance of endothelial damage in live/dead staining or apoptosis occurred at higher radiant exposure of 287 J/cm2. On enucleated rabbit and porcine corneas, ED50 was 87 and 52 J/cm2, respectively, by MVL, and 241 and 160 J/cm2 for endothelial damage. In human eyes, ED50 for MVL was 110 J/cm2 and endothelial damage at 453 J/cm2. Single-pulse iris damage occurred at ED 50 of 208 mJ/cm2. These values determine the energy permitted for surgical patterns and can guide development of ophthalmic laser systems. Lower damage threshold in corneas of enucleated eyes versus live rabbits is noted for future safety evaluation.
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Affiliation(s)
- Jenny Wang
- Stanford University, Department of Applied Physics, 452 Lomita Mall, Stanford, California 94305, United States
| | - Jae Lim Chung
- Stanford University, Department of Ophthalmology, 452 Lomita Mall, Stanford, California 94305, United StatescKonyang University, Kim's Eye Hospital, Department of Ophthalmology, 136 Yeongshin-ro, Youngdeungpo-gu, Seoul 150-034, Republic of Korea
| | - Georg Schuele
- Abbott Medical Optics, 1310 Moffett Park Drive, Sunnyvale, California 94089, United States
| | - Alexander Vankov
- Abbott Medical Optics, 1310 Moffett Park Drive, Sunnyvale, California 94089, United States
| | - Roopa Dalal
- Stanford University, Department of Ophthalmology, 452 Lomita Mall, Stanford, California 94305, United States
| | - Michael Wiltberger
- Abbott Medical Optics, 1310 Moffett Park Drive, Sunnyvale, California 94089, United States
| | - Daniel Palanker
- Stanford University, Department of Ophthalmology, 452 Lomita Mall, Stanford, California 94305, United StateseStanford University, Hansen Experimental Physics Laboratory, 452 Lomita Mall, Stanford, California 94305, United States
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Zheng LL, Vanchinathan V, Dalal R, Noolandi J, Waters DJ, Hartmann L, Cochran JR, Frank CW, Yu CQ, Ta CN. Biocompatibility of poly(ethylene glycol) and poly(acrylic acid) interpenetrating network hydrogel by intrastromal implantation in rabbit cornea. J Biomed Mater Res A 2015; 103:3157-65. [PMID: 25778285 DOI: 10.1002/jbm.a.35453] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/24/2015] [Accepted: 03/09/2015] [Indexed: 11/08/2022]
Abstract
We evaluated the biocompatibility of a poly(ethylene glycol) and poly(acrylic acid) (PEG/PAA) interpenetrating network hydrogel designed for artificial cornea in a rabbit model. PEG/PAA hydrogel measuring 6 mm in diameter was implanted in the corneal stroma of twelve rabbits. Stromal flaps were created with a microkeratome. Randomly, six rabbits were assigned to bear the implant for 2 months, two rabbits for 6 months, two rabbits for 9 months, one rabbit for 12 months, and one rabbit for 16 months. Rabbits were evaluated monthly. After the assigned period, eyes were enucleated, and corneas were processed for histology and immunohistochemistry. There were clear corneas in three of six rabbits that had implantation of hydrogel for 2 months. In the six rabbits with implant for 6 months or longer, the corneas remained clear in four. There was a high rate of epithelial defect and corneal thinning in these six rabbits. One planned 9-month rabbit developed extrusion of implant at 4 months. The cornea remained clear in the 16-month rabbit but histology revealed epithelial in-growth. Intrastromal implantation of PEG/PAA resulted in a high rate of long-term complications.
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Affiliation(s)
- Luo Luo Zheng
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California.,Department of Bioengineering, Stanford University School of Engineering, Stanford, California
| | - Vijay Vanchinathan
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Roopa Dalal
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Jaan Noolandi
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Dale J Waters
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, California
| | - Laura Hartmann
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, California
| | - Jennifer R Cochran
- Department of Bioengineering, Stanford University School of Engineering, Stanford, California
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, California
| | - Charles Q Yu
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Christopher N Ta
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
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Lorach H, Goetz G, Mandel Y, Lei X, Galambos L, Kamins TI, Mathieson K, Huie P, Dalal R, Harris JS, Palanker D. Performance of photovoltaic arrays in-vivo and characteristics of prosthetic vision in animals with retinal degeneration. Vision Res 2014; 111:142-8. [PMID: 25255990 DOI: 10.1016/j.visres.2014.09.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/11/2014] [Accepted: 09/15/2014] [Indexed: 11/19/2022]
Abstract
Loss of photoreceptors during retinal degeneration leads to blindness, but information can be reintroduced into the visual system using electrical stimulation of the remaining retinal neurons. Subretinal photovoltaic arrays convert pulsed illumination into pulsed electric current to stimulate the inner retinal neurons. Since required irradiance exceeds the natural luminance levels, an invisible near-infrared (915 nm) light is used to avoid photophobic effects. We characterized the thresholds and dynamic range of cortical responses to prosthetic stimulation with arrays of various pixel sizes and with different number of photodiodes. Stimulation thresholds for devices with 140 μm pixels were approximately half those of 70 μm pixels, and with both pixel sizes, thresholds were lower with 2 diodes than with 3 diodes per pixel. In all cases these thresholds were more than two orders of magnitude below the ocular safety limit. At high stimulation frequencies (>20 Hz), the cortical response exhibited flicker fusion. Over one order of magnitude of dynamic range could be achieved by varying either pulse duration or irradiance. However, contrast sensitivity was very limited. Cortical responses could be detected even with only a few illuminated pixels. Finally, we demonstrate that recording of the corneal electric potential in response to patterned illumination of the subretinal arrays allows monitoring the current produced by each pixel, and thereby assessing the changes in the implant performance over time.
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Affiliation(s)
- Henri Lorach
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA; Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA; Institut de la Vision, Paris 75012, France.
| | - Georges Goetz
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Yossi Mandel
- Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, 5290002, Israel
| | - Xin Lei
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Ludwig Galambos
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - Theodore I Kamins
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Keith Mathieson
- Institute of Photonics, University of Strathclyde, Scotland, UK
| | - Philip Huie
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA; Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - Roopa Dalal
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA; Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - James S Harris
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA; Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
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Mandel Y, Manivanh R, Dalal R, Huie P, Wang J, Brinton M, Palanker D. Vasoconstriction by electrical stimulation: new approach to control of non-compressible hemorrhage. Sci Rep 2014; 3:2111. [PMID: 23828130 PMCID: PMC3701318 DOI: 10.1038/srep02111] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 06/07/2013] [Indexed: 12/18/2022] Open
Abstract
Non-compressible hemorrhage is the most common preventable cause of death on battlefield and in civilian traumatic injuries. We report the use of microsecond pulses of electric current to induce rapid constriction in femoral and mesenteric arteries and veins in rats. Electrically-induced vasoconstriction could be induced in seconds while blood vessels dilated back to their original size within minutes after stimulation. At higher settings, a blood clotting formed, leading to complete and permanent occlusion of the vessels. The latter regime dramatically decreased the bleeding rate in the injured femoral and mesenteric arteries, with a complete hemorrhage arrest achieved within seconds. The average blood loss from the treated femoral artery during the first minute after injury was about 7 times less than that of a non-treated control. This new treatment modality offers a promising approach to non-damaging control of bleeding during surgery, and to efficient hemorrhage arrest in trauma patients.
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Affiliation(s)
- Yossi Mandel
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA.
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Abstract
Noncompressible hemorrhage is currently the most common cause of preventable death in battlefield and in civilian trauma injuries. Tourniquets, specialized wound dressings, and hemorrhage-inhibiting biomaterials are not sufficiently effective in arrest of noncompressible hemorrhage and often cause collateral tissue damage. An effective, easy-to-use, portable device is needed to reduce blood loss in trauma patients immediately following injury and to maintain hemorrhage control up to several hours-until the injured is evacuated to a medical facility. We developed a miniature electrical stimulator to induce vascular constriction and, thereby, reduce hemorrhage. Vasoconstriction of the rat femoral arteries and veins was studied with pulse durations in the range of 1 μs to 10 ms and repetition rate of 10 Hz. Pulse amplitude of 20 V, duration of 1 ms, and repetition rate of 10 Hz were found sufficient to induce rapid constriction down to 31 ± 2% of the initial diameter, which could be maintained throughout a two-hour treatment. Within one minute following treatment termination the artery dilated back to 88 ± 3% of the initial diameter, providing rapid restoration of blood perfusion. Histology indicated no damage to the vessel wall and endothelium seven days after stimulation. The same treatment reduced the blood loss following complete femoral artery resection by 68 ± 11%, compared to untreated vessels. Very low power consumption during stimulation (<10 mW per 1.6 mm electrode) allows miniaturization of the stimulator for portable battery-powered operation in the field to control the blood loss following vascular trauma.
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Bhatia S, Spector S, Dalal R, Echenique A, Narayanan G. Is antibiotic prophylaxis necessary for percutaneous radiofrequency ablation of hepatocellular carcinoma. J Vasc Interv Radiol 2014. [DOI: 10.1016/j.jvir.2013.12.487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Ho JK, Stanford MP, Shariati MA, Dalal R, Liao YJ. Optical coherence tomography study of experimental anterior ischemic optic neuropathy and histologic confirmation. Invest Ophthalmol Vis Sci 2013; 54:5981-8. [PMID: 23887804 DOI: 10.1167/iovs.13-12419] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
PURPOSE The optic nerve is part of the central nervous system, and interruption of this pathway due to ischemia typically results in optic atrophy and loss of retinal ganglion cells. In this study, we assessed in vivo retinal changes following murine anterior ischemic optic neuropathy (AION) by using spectral-domain optical coherence tomography (SD-OCT) and compared these anatomic measurements to that of histology. METHODS We induced ischemia at the optic disc via laser-activated photochemical thrombosis, performed serial SD-OCT and manual segmentation of the retinal layers to measure the ganglion cell complex (GCC) and total retinal thickness, and correlated these measurements with that of histology. RESULTS There was impaired perfusion and leakage at the optic disc on fluorescein angiography immediately after AION and severe swelling and distortion of the peripapillary retina on day-1. We used SD-OCT to quantify the changes in retinal thickness following experimental AION, which revealed significant thickening of the GCC on day-1 after ischemia followed by gradual thinning that plateaued by week-3. Thickness of the peripapillary sensory retina was also increased on day-1 and thinned chronically. This pattern of acute retinal swelling and chronic thinning on SD-OCT correlated well with changes seen in histology and corresponded to loss of retinal ganglion layer cells after ischemia. CONCLUSIONS This was a serial SD-OCT quantification of acute and chronic changes following experimental AION, which revealed changes in the GCC similar to that of human AION, but over a time frame of weeks rather than months.
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Affiliation(s)
- Joyce K Ho
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, California, USA
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Farooqui N, Myung D, Koh W, Masek M, Dalal R, Carrasco MR, Noolandi J, Frank CW, Ta CN. Histological Processing of pH-Sensitive Hydrogels Used in Corneal Implant Applications. J Histotechnol 2013. [DOI: 10.1179/his.2007.30.3.157] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Lavinsky D, Chalberg TW, Mandel Y, Huie P, Dalal R, Marmor M, Palanker D. Modulation of Transgene Expression in Retinal Gene Therapy by Selective Laser Treatment. ACTA ACUST UNITED AC 2013; 54:1873-80. [DOI: 10.1167/iovs.12-10933] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
| | | | - Yossi Mandel
- From the Department of Ophthalmology and the 2Hansen Experimental Physics Laboratory, Stanford University, Stanford, California; the
| | - Philip Huie
- From the Department of Ophthalmology and the 2Hansen Experimental Physics Laboratory, Stanford University, Stanford, California; the
| | - Roopa Dalal
- From the Department of Ophthalmology and the
| | | | - Daniel Palanker
- From the Department of Ophthalmology and the 2Hansen Experimental Physics Laboratory, Stanford University, Stanford, California; the
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Majzner R, Jin Z, Van de Ven C, Duffy D, Dalal R, Ricci A, Radhakrishnan K, Harrison L, Cairo M. Pulmonary Function (PF) After Stem Cell Transplant (SCT) Is Significantly Better in Children and Adolescents Who Receive Reduced Toxicity Conditioning (RTC) Versus Myeloablative Conditioning (MAC) and Significantly Decreased in Those Who Develop Chronic GVHD (cGVHD). Biol Blood Marrow Transplant 2012. [DOI: 10.1016/j.bbmt.2011.12.291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Deshpande P, Vadwai V, Shetty A, Dalal R, Soman R, Rodrigues C. No NDM-1 carriage in healthy persons from Mumbai: reassuring for now. J Antimicrob Chemother 2012; 67:1046-7. [DOI: 10.1093/jac/dkr580] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Affiliation(s)
- Young Sun
- Department of Ophthalmology, Room A-157, 300 Pasteur Dr, Stanford University School of Medicine, Palo Alto, CA 94305, USA
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Abstract
Neglected fracture dislocations of ankle are rare in western countries. Failure to achieve anatomic reduction is associated with a poor prognosis. We present a case of a patient with a neglected Weber B fracture of the fibula with postero-lateral subluxation of the ankle. In theatre, the subluxation could not be reduced, and a posterior and lateral soft tissue release was performed. Granulation tissue was removed from the medial gutter. The fibular fracture was reduced and fixed with a six-hole dynamic compression plate. Post-operative radiographs was satisfactory and the patient was followed up for 12 months with full range of movement and function of the joint. In our case, correction was not obtained by osteotomy of the lateral malleolus alone, and medial and posterior soft tissue release was required. This was due to disruption of the deltoid ligament and posterior tibiofibular ligament and the associated scar tissue. Previous studies have shown that, if anatomic reduction is achieved, results with delayed surgery can be as good as those obtained with immediate surgery. Surgically correcting an old fracture dislocation is a difficult undertaking due to soft-tissue contractures and malunited fractures. It is important to preserve as much soft tissue attachments and periosteum to prevent avascular necrosis.
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Affiliation(s)
- W S Khan
- Department of orthopaedics & trauma, Stepping hill hospital, Stockport, UK
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Abstract
A 41 year old man presented with pain and numbness affecting the lateral aspect of his foot after a steroid injection for plantar fasciitis. Examination confirmed numbness and motor impairment of the lateral plantar nerve. The findings were confirmed by electromyographic studies. The anatomy of the lateral plantar nerve and correct technique for injection to treat plantar fasciitis are discussed.
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Affiliation(s)
- D M Snow
- Stepping Hill Hospital, Stockport, UK.
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Molnar FE, Yellachich D, Leng T, Agurto R, Quiroz H, Dalal R, Huie P, Noolandi J, Blumenkranz MS, Marmor MF, Fishman HA. Behavioural difference of vascularized and non-vascularized retina after subretinal implantation of cellulose acetate membrane. J Vis 2004. [DOI: 10.1167/4.11.70] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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50
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Greco NJ, Tonon G, Chen W, Luo X, Dalal R, Jamieson GA. Novel structurally altered P(2X1) receptor is preferentially activated by adenosine diphosphate in platelets and megakaryocytic cells. Blood 2001; 98:100-7. [PMID: 11418468 DOI: 10.1182/blood.v98.1.100] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Experimental and clinical data suggest the presence of multiple types of adenosine diphosphate (ADP) receptors, one coupled to ligand-gated cation channels (P(2X)) and others coupled to G-protein-coupled (P(2Y)) receptors. This report identifies cDNA for a structurally altered P(2X1)-like receptor in megakaryocytic cell lines (Dami and CMK 11-5) and platelets that, when transfected into nonresponsive 1321 cells, confers a specific sensitivity to ADP with the pharmacologic rank order of ADP > > ATP > > > alpha,beta-methylene-ATP as measured by Ca(++) influx. This receptor (P(2X1del)) contains a deletion of 17 amino acids (PALLREAENFTLFIKNS) that includes an NFT consensus sequence for N-linked glycosylation. Glycosylated forms of the P(2X1del) and P(2X1wt) receptors were indistinguishable electrophoretically by Western blot or by immunoprecipitation using available antihuman and antirat antibodies. These results indicate that the expression of the P(2X1del) receptor results in an influx of Ca(++) induced by ADP. Expression of P(2X1del) receptor homomeric subunits is sufficient to express a receptor preferentially activated by ADP and suggests that this altered form, alone or in combination with P(2X1wt) receptors, is a component of an ADP-activated ion channel.
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MESH Headings
- Adenosine Diphosphate/pharmacology
- Blood Platelets/metabolism
- Calcium Signaling/drug effects
- Dose-Response Relationship, Drug
- Humans
- Megakaryocytes/metabolism
- Polymerase Chain Reaction
- Receptors, Purinergic/drug effects
- Receptors, Purinergic/genetics
- Receptors, Purinergic/metabolism
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2X
- Sequence Homology, Nucleic Acid
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- N J Greco
- Platelet Biology and the Product Development Departments, American Red Cross, Rockville, MD, USA.
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