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Ramos MF, Schafer KA, Sorden SD. Introduction to Special Issue on Ocular Pathology and Drug Development. Toxicol Pathol 2021; 49:417-418. [PMID: 33397210 DOI: 10.1177/0192623320986558] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dysfunction of the visual system remains a leading cause of human disability worldwide. Preclinical studies are a key component of efforts to develop drugs and devices to ameliorate visual impairment. Although new opportunities for the delivery of targeted ocular therapeutics have been created, clinical success has been confounded by unique challenges of drug development for the eye. This Special Issue brings together a broad range of articles that augment our current understanding of the visual system and highlight methods for assessing ocular toxicity and some of the current challenges in ocular drug development. Topics addressed include the anatomy, developmental anatomy, and/or immunobiology of the visual system and associated lymphoid tissues; animal models; methods for assessing ocular toxicity; spontaneous background and procedure-related microscopic findings and common artifacts in histologic sections of ocular tissues; and novel ocular drug delivery systems.
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Affiliation(s)
| | | | - Steven D Sorden
- Covance Laboratories Inc., Madison, WI, USA. Sorden is now with SDS Pathology, LLC, Fort Collins, Colorado, USA
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Abstract
Mucosa-associated lymphoid tissue (MALT) of special senses is poorly described and can be confused with nonspecific mononuclear cell infiltrates and tertiary lymphoid structures (TLS). In the eye, MALT consists mostly of conjunctiva-associated lymphoid tissue (CALT) and lacrimal drainage-associated lymphoid tissue (LDALT). In humans, CALT and LDALT are important components of the normal eye-associated lymphoid tissue (EALT), but EALT is less frequently described in ocular tissues of animals. The EALT are acquired postnatally in preferential mucosal sites, expand with antigenic exposure, form well-developed lymphoid follicles, and are reported to senesce. Lymphoid follicles that are induced concurrently with chronic inflammation are more appropriately considered TLS but must be differentiated from inflammation in MALT. Less understood is the etiology for formation of lymphoid tissue aggregates in the ciliary body, limbus, or choroid of healthy eyes in animals and humans. In the healthy eustachian tube and middle ear of animals and humans, MALT may be present but is infrequently described. Concurrent with otitis media, lymphoid follicles in the eustachian tube are probably expanded MALT, but lymphoid follicles in the middle ear may be TLS. The purpose of this comparative review is to familiarize toxicologic pathologists with MALT in the special senses and to provide considerations for differentiating and reporting eye and ear MALT from immune or inflammatory cell infiltrates or inflammation in nonclinical studies, and the circumstances for reporting TLS in compartments of the eye and ear.
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Lafond JF, Shimoji M, Ramaswamy B, Shukoor MI, Malik P, Shapiro B, Depireux DA. Middle Ear Histopathology Following Magnetic Delivery to the Cochlea of Prednisolone-loaded Iron Oxide Nanoparticles in Rats. Toxicol Pathol 2017; 46:101-106. [PMID: 28992726 DOI: 10.1177/0192623317732028] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Delivery of therapy to the cochlea is a challenge and limits the efficacy of therapies meant to treat hearing loss, reverse tinnitus, and protect hearing from chemotherapy regimens. Magnetic injection is a technique that uses magnetic fields to inject nanoparticles from the middle ear into the cochlea, where they can then elute therapy to treat hearing disorders. To evaluate the safety of this treatment in the middle ear, 30 rats were subdivided into 6 groups and treated by single or multiple intratympanic injections of saline, prednisolone, nanoparticles, or nanoparticles loaded with prednisolone. A specially designed magnet array was used to magnetically inject the particles from the middle ear to the cochlea. Treatment began at study day 0, and animals were euthanized on study day 2, 30, or 90. Temporal bones were collected and prepared for histopathological examination. Intratympanic administration of magnetic nanoparticles and/or prednisolone resulted in minimal to mild inflammatory changes in all treated groups. The incidence and severity of the inflammatory changes observed appeared slightly increased in animals administered nanoparticles, with or without prednisolone, when compared to animals administered prednisolone alone. At study day 90, there was partial reversibility of the findings noted at study day 2 and 30. Repeat administration did not appear to cause greater inflammatory changes.
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Affiliation(s)
| | | | - Bharath Ramaswamy
- 3 Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | | | - Pulkit Malik
- 3 Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | - Benjamin Shapiro
- 2 Otomagnetics, LLC, Rockville, Maryland, USA.,3 Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA.,4 Institute for Systems Research (ISR), University of Maryland, College Park, Maryland, USA
| | - Didier A Depireux
- 2 Otomagnetics, LLC, Rockville, Maryland, USA.,3 Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA.,4 Institute for Systems Research (ISR), University of Maryland, College Park, Maryland, USA.,5 Department of Otorhinolaryngology/Head and Neck Surgery, University of Maryland, Baltimore, Maryland, USA
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