Publications

2020

Liu Z, Xu J, Ma Q, Zhang X, Yang Q, Wang L, Cao Y, Xu Z, Tawfik A, Sun Y, Weintraub N, Fulton D, Hong M, Dong Z, Smith L, Caldwell R, Sodhi A, Huo Y. Glycolysis links reciprocal activation of myeloid cells and endothelial cells in the retinal angiogenic niche. Sci Transl Med. 2020;12(555).
The coordination of metabolic signals among different cellular components in pathological retinal angiogenesis is poorly understood. Here, we showed that in the pathological angiogenic vascular niche, retinal myeloid cells, particularly macrophages/microglia that are spatially adjacent to endothelial cells (ECs), are highly glycolytic. We refer to these macrophages/microglia that exhibit a unique angiogenic phenotype with increased expression of both M1 and M2 markers and enhanced production of both proinflammatory and proangiogenic cytokines as pathological retinal angiogenesis-associated glycolytic macrophages/microglia (PRAGMs). The phenotype of PRAGMs was recapitulated in bone marrow-derived macrophages or retinal microglia stimulated by lactate that was produced by hypoxic retinal ECs. Knockout of 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase (; for rodents), a glycolytic activator in myeloid cells, impaired the ability of macrophages/microglia to acquire an angiogenic phenotype, rendering them unable to promote EC proliferation and sprouting and pathological neovascularization in a mouse model of oxygen-induced proliferative retinopathy. Mechanistically, hyperglycolytic macrophages/microglia produced large amount of acetyl-coenzyme A, leading to histone acetylation and PRAGM-related gene induction, thus reprogramming macrophages/microglia into an angiogenic phenotype. These findings reveal a critical role of glycolytic metabolites as initiators of reciprocal activation of macrophages/microglia and ECs in the retinal angiogenic niche and suggest that strategies targeting the metabolic communication between these cell types may be efficacious in the treatment of pathological retinal angiogenesis.
Maleki A, Ueberroth J, Manhapra A, Walsh M, Asgari S, Chang P, Anesi S, Foster S. Fixed-Luminance and Multi-Luminance Flicker Electroretinography Parameters in Patients with Early Active Birdshot Chorioretinopathy. Ocul Immunol Inflamm. 2020;:1–7.
Purpose To evaluate the parameters of the Fixed-Luminance and Multi-Luminance flicker electroretinography protocol among patients with early active birdshot chorioretinopathy. Methods Fixed-Luminance magnitude, Fixed-Luminance phase, Multi-Luminance magnitude area under the curve, and Multi-Luminance phase area under the curve parameters were compared between early active birdshot chorioretinopathy patients and an age-matched control group. Results There was no statistically significant difference between the Fixed-Luminance flicker magnitude ( = .6), the Fixed-Luminance flicker phase ( = .9), and the Multi-Luminance flicker phase area under the curve ( = .55) when each was compared to the normal population; however, the difference between the mean Multi-Luminance flicker magnitude area under the curve in our patients and the healthy control group was statistically significant. ( = .003) Conclusions Multi-Luminance flicker magnitude area under the curve has been shown to be significantly different from the normal population in the early active course of the disease. Abbreviations BSCR: birdshot chorioretinopathy; cd: Cadmium; ERG: Electroretinography; FA: Fluorescein angiography; FL-: Fixed-luminance; HVF: Humphrey visual field; Hz: Hertz; ICG: Indocyanine green; m: Square meter; ML-: Multi-luminance; ms: millisecond; SITA: Swedish interactive thresholding algorithm; SWAP: Short wave-length automated perimetry.
Martínez-Carrasco R, Argüeso P, Fini E. Dynasore protects ocular surface mucosal epithelia subjected to oxidative stress by maintaining UPR and calcium homeostasis. Free Radic Biol Med. 2020;160:57–66.
The mucosal epithelia of the ocular surface protect against external threats to the eye. Using a model of human stratified corneal epithelial cells with mucosal differentiation, we previously demonstrated that a small molecule inhibitor of dynamin GTPases, dynasore, prevents damage to cells and their transcellular barriers when subjected to oxidative stress. Investigating mechanisms, we now report the novel finding that dynasore acts by maintaining Ca homeostasis, thereby inhibiting the PERK branch of the unfolded protein response (UPR) that promotes cell death. Dynasore was found to protect mitochondria by preventing mitochondrial permeability transition pore opening (mPTP), but, unlike reports using other systems, this was not mediated by dynamin family member DRP1. Necrostatin-1, an inhibitor of RIPK1 and lytic forms of programmed cell death, also inhibited mPTP opening and further protected the plasma membrane barrier. Significantly, necrostatin-1 did not protect the mucosal barrier. Oxidative stress increased mRNA for sXBP1, a marker of the IRE1 branch of the UPR, and CHOP, a marker of the PERK branch. It also stimulated phosphorylation of eIF2α, the upstream regulator of CHOP, as well as an increase in intracellular Ca. Dynasore selectively inhibited the increase in PERK branch markers, and also prevented the increase intracellular Ca in response to oxidative stress. The increase in PERK branch markers were also inhibited when cells were treated with the cell permeable Ca chelator, BAPTA-AM. To our knowledge, this is the first time that dynasore has been shown to have an effect on the UPR and suggests therapeutic applications.
Zucker C, Bernstein P, Schalek R, Lichtman J, Dowling J. A connectomics approach to understanding a retinal disease. Proc Natl Acad Sci U S A. 2020;117(31):18780–18787.
Macular telangiectasia type 2 (MacTel), a late-onset macular degeneration, has been linked to a loss in the retina of Müller glial cells and the amino acid serine, synthesized by the Müller cells. The disease is confined mainly to a central retinal region called the MacTel zone. We have used electron microscopic connectomics techniques, optimized for disease analysis, to study the retina from a 48-y-old woman suffering from MacTel. The major observations made were specific changes in mitochondrial structure within and outside the MacTel zone that were present in all retinal cell types. We also identified an abrupt boundary of the MacTel zone that coincides with the loss of Müller cells and macular pigment. Since Müller cells synthesize retinal serine, we propose that a deficiency of serine, required for mitochondrial maintenance, causes mitochondrial changes that underlie MacTel development.
Testi I, Agrawal R, Mahajan S, Agarwal A, Gunasekeran DV, Raje D, Aggarwal K, Murthy S, Westcott M, Chee SP, McCluskey P, Ho SL, Teoh S, Cimino L, Biswas J, Narain S, Agarwal M, Mahendradas P, Khairallah M, Jones N, Tugal-Tutkun I, Babu K, Basu S, Carreño E, Lee R, Al-Dhibi H, Bodaghi B, Invernizzi A, Goldstein D, Herbort C, Barisani-Asenbauer T, González-López J, Androudi S, Bansal R, Moharana B, Esposti SD, Tasiopoulou A, Nadarajah S, Agarwal M, Abraham S, Vala R, Singh R, Sharma A, Sharma K, Zierhut M, Kon OM, Cunningham E, Kempen J, Nguyen QD, Pavesio C, Gupta V. The Collaborative Ocular Tuberculosis Study (COTS)-1: A Multinational Descriptive Review of Tubercular Uveitis in Paediatric Population. Ocul Immunol Inflamm. 2020;:1–7.
PURPOSE: To examine disease profile of tubercular uveitis (TBU) in Paediatric population. METHODS: Among 945 patients of the retrospective multinational study by the Collaborative Ocular Tuberculosis Study (COTS)-1, 29 Paediatric patients diagnosed with TBU were analyzed. RESULTS: Mean age of disease presentation was 12.8 (range 4-18 years), with predominance of males (n = 14/20; 70.0%) and Asian ethnicity (n = 25/29; 86.2%). Posterior uveitis (n = 14/28; 50%) was the most frequent uveitis phenotype, with choroidal involvement occurring in 64.7% (n = 11/17). Incidence of optic disc edema and macular edema was higher in children (n = 8/18; 44.4% and n = 5/18; 27.8%, respectively) than in adults (n = 160/942; 16.9% and n = 135/942; 14.3%, respectively). Comparison of optic disc edema between subgroups showed a significant difference (). All patients received oral corticosteroids, most of them with antitubercular therapy. Treatment failure developed in 4.8% (n = 1/21). CONCLUSIONS: Children have a more severe inflammatory response to the disease, and an intensive anti-inflammatory therapeutic regimen is required to achieve a positive treatment outcome.
A normally sighted person can see a grating of 30 cycles per degree or higher, but spatial frequencies needed for motion perception are much lower than that. It is unknown for natural images with a wide spectrum how all the visible spatial frequencies contribute to motion speed perception. In this work, we studied the effect of spatial frequency content on motion speed estimation for sequences of natural and stochastic pixel images by simulating different visual conditions, including normal vision, low vision (low-pass filtering), and complementary vision (high-pass filtering at the same cutoff frequencies of the corresponding low-vision conditions) conditions. Speed was computed using a biological motion energy-based computational model. In natural sequences, there was no difference in speed estimation error between normal vision and low vision conditions, but it was significantly higher for complementary vision conditions (containing only high-frequency components) at higher speeds. In stochastic sequences that had a flat frequency distribution, the error in normal vision condition was significantly larger compared with low vision conditions at high speeds. On the contrary, such a detrimental effect on speed estimation accuracy was not found for low spatial frequencies. The simulation results were consistent with the motion direction detection task performed by human observers viewing stochastic sequences. Together, these results (i) reiterate the importance of low frequencies in motion perception, and (ii) indicate that high frequencies may be detrimental for speed estimation when low frequency content is weak or not present.
Singer M, Marchal F, Angelos P, Bernet V, Boucai L, Buchholzer S, Burkey B, Eisele D, Erkul E, Faure F, Freitag S, Gillespie MB, Harrell RM, Hartl D, Haymart M, Leffert J, Mandel S, Miller B, Morris J, Pearce E, Rahmati R, Ryan W, Schaitkin B, Schlumberger M, Stack B, Van Nostrand D, Wong KK, Randolph G. Salivary and lacrimal dysfunction after radioactive iodine for differentiated thyroid cancer: American Head and Neck Society Endocrine Surgery Section and Salivary Gland Section joint multidisciplinary clinical consensus statement of otolaryngology, ophth. Head Neck. 2020;
BACKGROUND: Postoperative radioactive iodine (RAI) administration is widely utilized in patients with differentiated thyroid cancer. While beneficial in select patients, it is critical to recognize the potential negative sequelae of this treatment. The prevention, diagnosis, and management of the salivary and lacrimal complications of RAI exposure are addressed in this consensus statement. METHODS: A multidisciplinary panel of experts was convened under the auspices of the American Head and Neck Society Endocrine Surgery and Salivary Gland Sections. Following a comprehensive literature review to assess the current best evidence, this group developed six relevant consensus recommendations. RESULTS: Consensus recommendations on RAI were made in the areas of patient assessment, optimal utilization, complication prevention, and complication management. CONCLUSION: Salivary and lacrimal complications secondary to RAI exposure are common and need to be weighed when considering its use. The recommendations included in this statement provide direction for approaches to minimize and manage these complications.
Singh RB, Sinha S, Saini C, Elbasiony E, Thakur S, Agarwal A. Recent advances in the management of non-infectious posterior uveitis. Int Ophthalmol. 2020;40(11):3187–3207.
PURPOSE: To review the current regimens and novel therapeutic modalities in various stages of research and development for the management of non-infectious posterior uveitis (NIPU). METHODS: We performed a thorough review of current literature using PubMed, Google Scholar and Clinicaltrials.gov to identify the published literature about the available therapeutics and novel drugs/therapies in different stages of clinical trials. RESULTS: The current management regimen for non-infectious posterior uveitis includes corticosteroids, immunomodulatory therapies and anti-metabolites. However, NIPU requires long-term management for efficacious remission of the disease and to prevent disease relapse. Long-term safety issues associated with steroids have led to efforts to develop novel therapeutic agents including biological response modulators and immunosuppressants. The current therapeutic agents in various stages of development include calcineurin inhibitors, biologic response modifiers and a more a comprehensive modalities like ocular gene therapy as well as novel drug delivery mechanisms for higher bioavailability to the target tissues, with minimal systemic effects. CONCLUSION: Novel efficacious therapeutic modalities under development will help overcome the challenges associated with the traditional therapeutic agents.
Moein HR, Akhlaq A, Dieckmann G, Abbouda A, Pondelis N, Salem Z, Müller R, Cruzat A, Cavalcanti B, Jamali A, Hamrah P. Visualization of micro-neuromas by using in vivo confocal microscopy: An objective biomarker for the diagnosis of neuropathic corneal pain?. Ocul Surf. 2020;
PURPOSE: The diagnosis of neuropathic corneal pain (NCP) is challenging, as it is often difficult to differentiate from conventional dry eye disease (DED). In addition to eye pain, NCP can present with similar signs and symptoms of DED. The purpose of this study is to find an objective diagnostic sign to identify patients with NCP, using in vivo confocal microscopy (IVCM). METHODS: This was a comparative, retrospective, case-control study. Patients with clinical diagnosis of NCP (n = 25), DED (n = 30), and age and sex-matched healthy controls (n = 16), who underwent corneal imaging with IVCM (HRT3/RCM) were included. Central corneal IVCM scans were analyzed by 2 masked observers for nerve density and number, presence of micro-neuromas (terminal enlargements of subbasal corneal nerve) and/or nerve beading (bead-like formation along the nerves), and dendritiform cell (DC) density. RESULTS: There was a decrease in total nerve density in both NCP (14.14 ± 1.03 mm/mm) and DED patients (12.86 ± 1.04 mm/mm), as compared to normal controls (23.90 ± 0.92 mm/mm; p < 0.001). However, total nerve density was not statistically different between NCP and DED patients (p = 0.63). Presence of nerve beading was not significantly different between patients and normal controls (p = 0.15). Interestingly, micro-neuromas were observed in all patients with NCP, while they were not present in any of the patients with DED (sensitivity and specificity of 100%). DC density was increased significantly in both NCP (71.89 ± 16.91 cells/mm) and DED patients (111.5 ± 23.86 cells/mm), as compared to normal controls (24.81 ± 4.48 cells/mm (Colloca et al., 2017) [2]; p < 0.05). However, there was no significant difference in DC density between DED and NCP patients (p = 0.31). CONCLUSION: IVCM may be used as an adjunct diagnostic tool for the diagnosis of NCP in the presence of neuropathic symptoms. Micro-neuromas may serve as a sensitive and specific biomarker for the diagnosis of NCP.