Publications

2020

Valdes L, Bispo P, Sobrin L. Application of Metagenomic Sequencing in the Diagnosis of Infectious Uveitis. Semin Ophthalmol. 2020;:1–4.
: to summarize the origin and very recent history of the use of metagenomic sequencing for the diagnosis of infectious uveitis, convey the technique as described by one of the primary institutions experimenting with the technology, and present recent successful applications of the technology as well as potential advantages and pitfalls compared to other current diagnostic tools.: review of peer-reviewed literature concerning metagenomic sequencing for the diagnosis of infectious uveitis.: compared to existing diagnostic methods, metagenomic deep sequencing is a sensitive, unbiased, and comprehensive technique with great potential for diagnosing the causative pathogens of cases of infectious uveitis. However, many issues remain to be addressed in the process of developing this technology, including but not limited to the potentially overwhelming amount of information generated, definition of diagnostic thresholds, demonstration of validity, contamination, and cost.
Steinberg E, Fluksman A, Zemmour C, Tischenko K, Karsch-Bluman A, Brill-Karniely Y, Birsner A, D’Amato R, Benny O. Low dose amiodarone reduces tumor growth and angiogenesis. Sci Rep. 2020;10(1):18034.
Amiodarone is an anti-arrhythmic drug that was approved by the US Food and Drug Administration (FDA) in 1985. Pre-clinical studies suggest that Amiodarone induces cytotoxicity in several types of cancer cells, thus making it a potential candidate for use as an anti-cancer treatment. However, it is also known to cause a variety of severe side effects. We hypothesized that in addition to the cytotoxic effects observed in cancer cells Amiodarone also has an indirect effect on angiogensis, a key factor in the tumor microenvironment. In this study, we examined Amiodarone's effects on a murine tumor model comprised of U-87 MG glioblastoma multiforme (GBM) cells, known to form highly vascularized tumors. We performed several in vitro assays using tumor and endothelial cells, along with in vivo assays utilizing three murine models. Low dose Amiodarone markedly reduced the size of GBM xenograft tumors and displayed a strong anti-angiogenic effect, suggesting dual cancer fighting properties. Our findings lay the ground for further research of Amiodarone as a possible clinical agent that, used in safe doses, maintains its dual properties while averting the drug's harmful side effects.
Jacob A, Brun L, Gil PJ, Ménard L, Bouzelha M, Broucque F, Roblin A, Vandenberghe L, Adjali O, Robin C, François A, Blouin V, Penaud-Budloo M, Ayuso E. Homologous Recombination Offers Advantages Over Transposition-Based Systems to Generate Recombinant Baculovirus for Adeno-Associated Viral Vector Production. Biotechnol J. 2020;:e2000014.
Viral vectors have a great potential for gene delivery, but manufacturing at a pharmaceutical scale is a big challenge for the industry. The baculovirus-insect cell system is one of the most scalable platforms to produce clinical-grade recombinant Adeno-Associated Virus (rAAV) vectors. The standard procedure to generate recombinant baculovirus is based on Tn7 transposition which is time-consuming and still suffers technical constraints. Moreover, werecently showed that baculoviral sequences adjacent to the AAV ITRs are preferentially encapsidated into the rAAV vector particles. This observation raised concerns about safety for clinical applications due to the presence of bacterial and antibiotic resistance coding sequences with a Tn7-mediated system for the construction of baculoviruses reagents. Here, weinvestigated a faster and safer method based on homologous recombination (HR). First, weconfirmed the functionality of the inserted cassette and the absence of undesirable genes into HR-derived baculoviral genomes. Strikingly, wefound that the exogenous cassette showed increased stability over passages when using the HR system. Finally, wetested these materials to produce rAAV vectors. The baculoviruses originated from both systems lead to high rAAV vector genome yields, with the advantage of the HR system being exempted from undesirable bacterial genes which provides an additional level of safety for the manufacturing of rAAV vectors. Overall, this study highlights the importance of the upstream process and starting biologic materials to generate safer rAAV biotherapeutic products. This article is protected by copyright. All rights reserved.
On the occasion of being awarded the Prentice Medal, I was asked to summarize my translational journey. Here I describe the process of becoming a low-vision rehabilitation clinician and researcher, frustrated by the unavailability of effective treatments for some conditions. This led to decades of working to understand patients' needs and the complexities and subtleties of their visual systems and conditions. It was followed by many iterations of developing vision aids and the techniques needed to objectively evaluate their benefit. I specifically address one path: the invention and development of peripheral prisms to expand the visual fields of patients with homonymous hemianopia, leading to our latest multiperiscopic prism (mirror-based design) with its clear 45° field-of-view image shift.
Ramier A, Eltony A, Chen Y, Clouser F, Birkenfeld J, Watts A, Yun SH. In vivo measurement of shear modulus of the human cornea using optical coherence elastography. Sci Rep. 2020;10(1):17366.
Corneal stiffness plays a critical role in shaping the cornea with respect to intraocular pressure and physical interventions. However, it remains difficult to measure the mechanical properties noninvasively. Here, we report the first measurement of shear modulus in human corneas in vivo using optical coherence elastography (OCE) based on surface elastic waves. In a pilot study of 12 healthy subjects aged between 25 and 67, the Rayleigh-wave speed was 7.86 ± 0.75 m/s, corresponding to a shear modulus of 72 ± 14 kPa. Our data reveal two unexpected trends: no correlation was found between the wave speed and IOP between 13-18 mmHg, and shear modulus decreases with age (- 0.32 ± 0.17 m/s per decade). We propose that shear stiffness is governed by the interfibrillar matrix, whereas tensile strength is dominated by collagen fibrils. Rayleigh-wave OCE may prove useful for clinical diagnosis, refractive surgeries, and treatment monitoring.
Shire D, Gingerich M, Wong P, Skvarla M, Cogan S, Chen J, Wang W, Rizzo J. Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis. Micromachines (Basel). 2020;11(10).
We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School's teaching hospital, the Massachusetts Eye and Ear-and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.
BACKGROUND: Glaucoma is one of the leading causes of blindness worldwide. Treatment is still largely targeted at lowering intraocular pressure. Intraocular pressures can be lowered through a variety of topical medications, lasers and incisional surgeries. There are currently several classes of topical medications available in the US that are aimed at lowering intraocular pressure through a variety of different mechanisms. Additionally, there have been numerous different formulations and fixed-dose combination medications that offer greatly expanded treatment options over the last several years. The wide variety of topical medications aim to address the issues with compliance, effectiveness and side effect profile that vary among each individual patient and disease.  Purpose: Three new topical medications, netarsudil 0.02%, latanoprostene bunod 0.24% and fixed-dose combination netarsudil 0.02% - latanoprost 0.005% have been approved in the US market to treat glaucoma. This review article will summarize the studies looking at their effectiveness and side effect profiles and discuss their utilization in the treatment of glaucoma. Additionally, we will briefly discuss future directions of research in topical glaucoma medications. CONCLUSION: Three new topical glaucoma medications offer additional treatment options for patient with glaucoma. Further research is needed to better understand the utility of sustained release formulations in the treatment of glaucoma.
Agranat J, Douglas V, Douglas KA, Miller J. A guarded light pipe for direct visualization during primary scleral buckling on the Ngenuity platform. Int J Retina Vitreous. 2020;6:42.
Background: Visualization during scleral buckling is traditionally achieved via indirect ophthalmoscopy. Recent advances have utilized the surgical microscope and a 25 gauge cannula-based endoillumination system, also known as a Chandelier lighting system. This report details an improved approach using a guarded 25 or 27 gauge light pipe and the Ngenuity digital three dimensional platform. Methods: A standard Alcon light pipe is modified with a silicone guard to expose only 5 mm of the tip of the light pipe. The guard is created from the silicone that is already opened to secure the ends of the encircling band most often employed sleeve (e.g. 70, 270). This guarded light pipe is then inserted into the cannula as an alternative to a Chandelier lighting system. Results: This is a technical report of a surgical visualization technique using a three dimensional digital visualization platform with a modified handheld vitrectomy light pipe. Conclusion: The utilization of a guarded light pipe for visualization during primary scleral buckling is a promising, effective, and efficient technique. The three dimensional digital display allows for better educational impact and surgical communication with trainees and ancillary members of the surgical team.
Park E, Tsikata E, Lee JJ, Shieh E, Braaf B, Vakoc B, Bouma B, Boer J, Chen T. Artifact Rates for 2D Retinal Nerve Fiber Layer Thickness Versus 3D Neuroretinal Rim Thickness Using Spectral-Domain Optical Coherence Tomography. Transl Vis Sci Technol. 2020;9(10):10.
Purpose: To compare the rates of clinically significant artifacts for two-dimensional peripapillary retinal nerve fiber layer (RNFL) thickness versus three-dimensional (3D) neuroretinal rim thickness using spectral-domain optical coherence tomography (SD-OCT). Methods: Only one eye per patient was used for analysis of 120 glaucoma patients and 114 normal patients. For RNFL scans and optic nerve scans, 15 artifact types were calculated per B-scan and per eye. Neuroretinal rim tissue was quantified by the minimum distance band (MDB). Global MDB neuroretinal rim thicknesses were calculated before and after manual deletion of B-scans with artifacts and subsequent automated interpolation. A clinically significant artifact was defined as one requiring manual correction or repeat scanning. Results: Among glaucomatous eyes, artifact rates per B-scan were significantly more common in RNFL scans (61.7%, 74 of 120) compared to B-scans in neuroretinal rim volume scans (20.9%, 1423 of 6820) (95% confidence interval [CI], 31.6-50.0; < 0.0001). For clinically significant artifact rates per eye, optic nerve scans had significantly fewer artifacts (15.8% of glaucomatous eyes, 13.2% of normal eyes) compared to RNFL scans (61.7% of glaucomatous eyes, 25.4% of normal eyes) (glaucoma group: 95% CI, 34.1-57.5, < 0.0001; normal group: 95% CI, 1.3-23.3, = 0.03). Conclusions: Compared to the most commonly used RNFL thickness scans, optic nerve volume scans less frequently require manual correction or repeat scanning to obtain accurate measurements. Translational Relevance: This paper illustrates the potential for 3D OCT algorithms to improve in vivo imaging in glaucoma.