276 results on '"Demetrios G Vavvas"'
Search Results
252. Metabolomic-derived endotypes of age-related macular degeneration (AMD): a step towards identification of disease subgroups
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Kevin Mendez, Ines Lains, Rachel S. Kelly, João Gil, Rufino Silva, John Miller, Demetrios G. Vavvas, Ivana Kim, Joan Miller, Liming Liang, Jessica A. Lasky-Su, and Deeba Husain
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Age-related macular degeneration ,AMD ,Metabolomics ,Endotyping ,Metabo-endotypes ,Medicine ,Science - Abstract
Abstract Age-related macular degeneration (AMD) is a leading cause of blindness worldwide, with a complex pathophysiology and phenotypic diversity. Here, we apply Similarity Network Fusion (SNF) to cluster AMD patients into putative metabolomics-derived endotypes. Using a discovery cohort of 163 AMD patients from Boston, US, and a validation cohort of 214 patients from Coimbra, Portugal, we identified four distinct metabolomics-derived endotypes with varying retinal structural and functional characteristics, confirmed across both cohorts. Patients clustered into Endotype 1 exhibited a milder form of AMD and were characterized by low levels of amino acids in specific metabolic pathways. Meanwhile, patients clustered into both Endotype 3 and 4 were associated with more severe AMD and exhibited low levels of fatty acid metabolites and elevated levels of sphingomyelins and fatty acid metabolites, respectively. These preliminary findings indicate that metabolomics-derived endotyping may offer a refined strategy for categorizing AMD patients based on their specific pathophysiological underpinnings, rather than relying solely on traditional observational clinical indicators.
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- 2024
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253. Structure-based network analysis predicts pathogenic variants in human proteins associated with inherited retinal disease
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Blake M. Hauser, Yuyang Luo, Anusha Nathan, Ahmad Al-Moujahed, Demetrios G. Vavvas, Jason Comander, Eric A. Pierce, Emily M. Place, Kinga M. Bujakowska, Gaurav D. Gaiha, and Elizabeth J. Rossin
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Medicine ,Genetics ,QH426-470 - Abstract
Abstract Advances in gene sequencing technologies have accelerated the identification of genetic variants, but better tools are needed to understand which are causal of disease. This would be particularly useful in fields where gene therapy is a potential therapeutic modality for a disease-causing variant such as inherited retinal disease (IRD). Here, we apply structure-based network analysis (SBNA), which has been successfully utilized to identify variant-constrained amino acid residues in viral proteins, to identify residues that may cause IRD if subject to missense mutation. SBNA is based entirely on structural first principles and is not fit to specific outcome data, which makes it distinct from other contemporary missense prediction tools. In 4 well-studied human disease-associated proteins (BRCA1, HRAS, PTEN, and ERK2) with high-quality structural data, we find that SBNA scores correlate strongly with deep mutagenesis data. When applied to 47 IRD genes with available high-quality crystal structure data, SBNA scores reliably identified disease-causing variants according to phenotype definitions from the ClinVar database. Finally, we applied this approach to 63 patients at Massachusetts Eye and Ear (MEE) with IRD but for whom no genetic cause had been identified. Untrained models built using SBNA scores and BLOSUM62 scores for IRD-associated genes successfully predicted the pathogenicity of novel variants (AUC = 0.851), allowing us to identify likely causative disease variants in 40 IRD patients. Model performance was further augmented by incorporating orthogonal data from EVE scores (AUC = 0.927), which are based on evolutionary multiple sequence alignments. In conclusion, SBNA can used to successfully identify variants as causal of disease in human proteins and may help predict variants causative of IRD in an unbiased fashion.
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- 2024
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254. Exercise diminishes the activity of acetyl-CoA carboxylase in human muscle
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Asish K. Saha, Erik A. Richter, Bente Kiens, Jens R. Daugaard, Lee A. Witters, Martin E. Young, Sven Asp, Ki-Han Kim, David J. Dean, Demetrios G. Vavvas, and Neil B. Ruderman
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Adult ,Male ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Physical Exertion ,Physical exercise ,Oxygen Consumption ,Reference Values ,Internal medicine ,Internal Medicine ,medicine ,Animals ,Humans ,Citrates ,Muscle, Skeletal ,Respiratory exchange ratio ,Beta oxidation ,Chemistry ,Acetyl-CoA carboxylase ,Skeletal muscle ,Metabolism ,Carbohydrate ,Rats ,Malonyl Coenzyme A ,Kinetics ,Endocrinology ,medicine.anatomical_structure ,Exercise intensity ,Acetyl-CoA Carboxylase - Abstract
Studies in rats suggest that increases in fatty acid oxidation in skeletal muscle during exercise are related to the phosphorylation and inhibition of acetyl-CoA carboxylase (ACC), and secondary to this, a decrease in the concentration of malonyl-CoA. Studies in human muscle have not revealed a consistent decrease in the concentration of malonyl-CoA during exercise; however, measurements of ACC activity have not been reported. Thus, whether the same mechanism operates in human muscle in response to physical activity remains uncertain. To investigate this question, ACC was immunoprecipitated from muscle of human volunteers and its activity assayed in the same individual at rest and after one-legged knee-extensor exercise at 60, 85, and 100% of knee extensor VO2max. ACC activity was diminished by 50-75% during exercise with the magnitude of the decrease generally paralleling exercise intensity. Treatment of the immunoprecipitated enzyme with protein phosphatase 2A restored activity to resting values, suggesting the decrease in activity was due to phosphorylation. The measurement of malonyl-CoA in the muscles revealed that its concentration is 1/10 of that in rats, and that it is diminished (12-17%) during the higher-intensity exercises. The respiratory exchange ratio increased with increasing exercise intensity from 0.84 +/- 0.02 at 60% to 0.99 0.04 at 100% VO2max. Calculated rates of whole-body fatty acid oxidation were 121 mg/min at rest and 258 +/- 35, 264 +/- 63, and 174 +/- 76 mg/min at 60, 85, and 100% VO2max, respectively. The results show that ACC activity, and to a lesser extent malonyl-CoA concentration, in human skeletal muscle decrease during exercise. Although these changes may contribute to the increases in fat oxidation from rest to exercise, they do not appear to explain the shift from mixed fuel to predominantly carbohydrate utilization when exercise intensity is increased.
255. Inhibitory effect of aminoimidazole carboxamide ribonucleotide (AICAR) on endotoxin-induced uveitis in rats
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Yuki Morizane, Joan W. Miller, Demetrios G. Vavvas, Maki Kayama, Jun Suzuki, Lucia Sobrin, Kimio Takeuchi, A. Manola, and Yusuke Murakami
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Adenosine monophosphate ,Lipopolysaccharides ,Male ,Salmonella typhimurium ,Chemokine ,Lipopolysaccharide ,Anterior Chamber ,CD14 ,Blotting, Western ,AICA ribonucleotide ,Anti-Inflammatory Agents ,Lipopolysaccharide Receptors ,Enzyme-Linked Immunosorbent Assay ,Pharmacology ,Peripheral blood mononuclear cell ,Retina ,Aqueous Humor ,chemistry.chemical_compound ,medicine ,Animals ,RNA, Messenger ,Chemokine CCL2 ,biology ,Reverse Transcriptase Polymerase Chain Reaction ,Tumor Necrosis Factor-alpha ,Monocyte ,NF-kappa B ,Ribonucleotides ,Aminoimidazole Carboxamide ,Intercellular Adhesion Molecule-1 ,Uveitis, Anterior ,eye diseases ,Rats ,Disease Models, Animal ,medicine.anatomical_structure ,chemistry ,Rats, Inbred Lew ,biology.protein ,Tumor necrosis factor alpha ,sense organs ,Injections, Intraperitoneal - Abstract
PURPOSE. To investigate the anti-inflammatory effect of aminoimidazole carboxamide ribonucleotide (AICAR), an analog of adenosine monophosphate (AMP), in endotoxin-induced uveitis (EIU). METHODS. EIU was induced by subcutaneous injection of lipopolysaccharide (LPS) (200 μg) in Lewis rats. AICAR (50 mg/kg, intraperitoneally) was given 6 hours prior and at the same time as LPS injection. Clinical uveitis scores, number of anterior chamber (AC) infiltrating cells, anterior chamber protein concentration, retinal vessel leukocyte adhesion, and protein leakage were measured 24 hours later. Protein levels of C-C chemokine ligand-2 (CCL-2)/monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-α (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) in aqueous humor and retina and nuclear translocation of nuclear factor-κB (NF-κB) in the retina were determined by enzyme-linked immunosorbent assay (ELISA). Both mRNA and protein levels of CD14 in peripheral blood mononuclear cells were also measured. RESULTS. AICAR treatment significantly reduced EIU clinical severity as well as inflammatory cell infiltration and protein concentration in aqueous humor. Similarly, the number of retinal vessel-adherent leukocytes and protein leakage were decreased by AICAR treatment. Protein levels of TNF-α, CCL-2/MCP-1, and ICAM-1 in aqueous humor and CCL-2/MCP-1 and ICAM-1 levels in retina were suppressed with AICAR treatment. AICAR also reduced NF-κB translocation and CD14 expression. CONCLUSIONS. AICAR reduces systemic LPS susceptibility and attenuates intraocular inflammation in a rat EIU model by limiting infiltration of leukocytes, suppressing inflammatory mediators, and inhibiting the NF-κB pathway.
256. Enhanced depth imaging optical coherence tomography in age-related macular degeneration
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Demetrios G. Vavvas, Dimitra Skondra, and Thanos D. Papakostas
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genetic structures ,Optics ,Optical coherence tomography ,Geographic Atrophy ,Age related ,medicine ,Humans ,medicine.diagnostic_test ,Choroid ,business.industry ,Organ Size ,General Medicine ,Macular degeneration ,medicine.disease ,eye diseases ,Ophthalmology ,medicine.anatomical_structure ,Wet Macular Degeneration ,sense organs ,Tomography ,Imaging technique ,Enhanced depth imaging ,business ,Tomography, Optical Coherence ,Biomedical engineering - Abstract
Imaging of the choroidal layer has been limited with the conventional commercial SD-OCTs. Enhanced depth imaging optical coherence tomography (EDI-OCT) is a modification of the standard spectral-domain OCT (SD-OCT) technique that enables better non-invasive imaging of the choroid. This review contains an introduction of EDI imaging technique and principles and summarizes the findings of EDI-OCT imaging in age-related macular degeneration.
257. Peripheral monocytes and neutrophils promote photoreceptor cell death in an experimental retinal detachment model
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Daniel E. Maidana, Lucia Gonzalez-Buendia, Sara Pastor-Puente, Afsar Naqvi, Eleftherios Paschalis, Andrius Kazlauskas, Joan W. Miller, and Demetrios G. Vavvas
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Cytology ,QH573-671 - Abstract
Abstract Photoreceptor cell death and immune cell infiltration are two major events that contribute to retinal degeneration. However, the relationship between these two events has not been well delineated, primarily because of an inadequate understanding of the immunological processes involved in photoreceptor degeneration, especially that of peripheral leukocytes that infiltrate the subretinal space and retinal tissues. In this work, we characterized the role of leukocyte infiltration within the detached retina. We observed that CD45+ CD11b+ Ly6G+ neutrophils and CD45+ CD11b+ Ly6G− Ly6C+ monocytes are the predominant peripheral immune cell populations that infiltrate the retinal and subretinal space after detachment. Selective depletion of monocytes or neutrophils using cell-specific targeting is neuroprotective for photoreceptors. These results indicate that peripheral innate immune cells contribute to photoreceptor degeneration, and targeting these immune cell populations could be therapeutic during retinal detachment.
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- 2023
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258. Retraction Note: Verteporfin-induced formation of protein cross-linked oligomers and high molecular weight complexes is mediated by light and leads to cell toxicity
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Eleni K. Konstantinou, Shoji Notomi, Cassandra Kosmidou, Katarzyna Brodowska, Ahmad Al-Moujahed, Fotini Nicolaou, Pavlina Tsoka, Evangelos Gragoudas, Joan W. Miller, Lucy H. Young, and Demetrios G. Vavvas
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Medicine ,Science - Published
- 2024
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259. Early recurrence of macular schisis in X-linked retinoschisis treated with vitrectomy for rhegmatogenous retinal detachment under silicone oil: case report and brief literature review
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Panagiotis Stavrakas, Foteini Tsapardoni, Efthymios Karmiris, Ioannis Iatropoulos, Konstantinos Kounas, Spyridon Lygeros, Vassilios Kozobolis, and Demetrios G. Vavvas
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Ophthalmology ,RE1-994 - Abstract
X-linked retinoschisis (XLRS) is an inherited retinal degeneration affecting males, characterized by splitting of the retinal layers. We herein present the outcomes of surgical treatment in a case of XLRS complicated by rhegmatogenous retinal detachment (RRD). A 22-year-old male presented to the emergency department due to decreased visual acuity and visual field defect in his left eye Oculus Sinister (OS) of 1 week duration. The patient reported an early onset retinal degeneration and decreased visual acuity in both eyes since childhood in his past ocular history. Upon presentation, best corrected visual acuity (BCVA) was 6/30 on the right eye Oculus Dexter (OD) and 6/120 OS. Fundus examination revealed areas of peripheral retinal schisis, and the characteristic spoke wheel pattern on the macula of both eyes. In OS, a temporal RRD involving the macula was identified. The patient underwent surgical treatment with pars plana vitrectomy with internal limiting membrane (ILM) peeling, endolaser, and silicone oil (SO) tamponade. BCVA in OS improved to 6/60 and schistic cavities resolution was observed in the immediate postoperative period. The patient’s BCVA further improved to 6/19 at 1 month, as foveal anatomy showed relative improvement. However, there was a rapid reappearance of schisis spaces in the macular area at this point, which was also followed by progressive deterioration of foveal schisis by 3 months post-operatively. The resorption and recurrence of lamellar macular schisis changes after ILM peel and presence of SO, highlights that although XLRS findings can temporarily improve upon surgical intervention, the pathogenetic mechanisms contributing to disease phenotype remain to be elucidated.
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- 2024
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260. Systemic Dyslipidemia in Age-related Macular Degeneration
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Brandon Li, Deborah Goss, Joan W. Miller, MD, Jonathan B. Lin, MD, PhD, and Demetrios G. Vavvas, MD, PhD
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Age-related macular degeneration ,Lipids ,Meta-analysis ,Cholesterol ,Ophthalmology ,RE1-994 - Abstract
Topic: Though lipid and cholesterol dyshomeostasis is thought to contribute to the pathogenesis of age-related macular degeneration (AMD), there is no consensus regarding which elements of systemic lipid homeostasis are perturbed in AMD. In this systematic review and meta-analysis, an update to that performed by Wang et al in 2016, we characterized serum lipoprotein profiles in patients with AMD and its various stages. Clinical Relevance: These findings may identify novel therapeutic approaches for AMD, a leading cause of blindness among older adults in the industrialized world. Methods: We used MEDLINE, Embase, and Web of Science to identify articles from database inception to May 2022 that reported blood/serum levels of lipid subspecies (triglycerides [TGs], total cholesterol [TC], low-density lipoprotein [LDL], and high-density lipoprotein [HDL]) in patients with AMD compared with controls. We meta-analyzed the data by generating multilevel random-effects models using restricted maximum likelihood estimation. Results: Our updated meta-analysis included 56 studies, almost 3 times as many studies as the 2016 meta-analysis with a total of 308 188 participants. There were no significant differences in serum TG, TC, LDL, or HDL between patients with AMD and non-AMD controls. Given significant heterogeneity, we performed subanalyses specifically in patients with early to intermediate nonexudative AMD, advanced nonexudative AMD, and advanced exudative AMD. Compared with non-AMD controls, patients with early to intermediate nonexudative AMD had significantly lower serum TG (standardized mean difference [SMD]: −0.03; 95% confidence interval [95% CI]: −0.06 to −0.01) and higher serum HDL (SMD: 0.07; 95% CI: 0.04–0.11). Patients with advanced exudative AMD had significantly higher serum LDL (SMD: 0.33; 95% CI: 0.04–0.62) compared with non-AMD controls. There were no other significant differences identified. Conclusion: We found that there is significant heterogeneity in systemic lipoproteins in patients with AMD compared with non-AMD controls. The specific pattern of lipid dyshomeostasis appeared to be distinct based on AMD stage. These findings highlight both the underlying heterogeneity of AMD as well as the presence of distinct pathophysiological mechanisms involved at different stages or subtypes of AMD and may inform the development of novel therapeutic approaches. Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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- 2024
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261. UVA induces retinal photoreceptor cell death via receptor interacting protein 3 kinase mediated necroptosis
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Zhen Yu, Victor S. M. C. Correa, Nikolaos E. Efstathiou, Henar Albertos-Arranz, Xiaohong Chen, Kenji Ishihara, Yasuhiro Iesato, Toshio Narimatsu, Dimitrios Ntentakis, and Demetrios G. Vavvas
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Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 ,Cytology ,QH573-671 - Abstract
Abstract Ultraviolet light A (UVA) is the only UV light that reaches the retina and can cause indirect damage to DNA via absorption of photons by non-DNA chromophores. Previous studies demonstrate that UVA generates reactive oxygen species (ROS) and leads to programmed cell death. Programmed cell death (PCD) has been implicated in numerous ophthalmologic diseases. Here, we investigated receptor interacting protein 1 and 3 (RIPK1 and RIPK3) kinases, key signaling molecules of PCD, in UVA-induced photoreceptor injury using in vitro and ex vivo models. UVA irradiation activated RIPK3 but not RIPK1 and mediated necroptosis through MLKL that lie downstream of RIPK3 and induced apoptosis through increased oxidative stress. Moreover, RIPK3 but not RIPK1 inhibition suppresses UVA-induced cell death along with the downregulation of MLKL and attenuates the levels of oxidative stress and DNA fragmentation. In conclusion, these results identify RIPK3, not RIPK1, as a critical regulator of UVA-induced necroptosis cell death in photoreceptors and highlight RIPK3 potential as a neuroprotective target.
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- 2022
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262. Receptor interacting protein 3 kinase, not 1 kinase, through MLKL-mediated necroptosis is involved in UVA-induced corneal endothelium cell death
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Zhen Yu, Nikolaos E. Efstathiou, Victor S. M. C. Correa, Xiaohong Chen, Kenji Ishihara, Yasuhiro Iesato, Toshio Narimatsu, Dimitrios Ntentakis, Yanyun Chen, and Demetrios G. Vavvas
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Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 ,Cytology ,QH573-671 - Abstract
Abstract Ultraviolet (UV) is one of the most energetic radiations in the solar spectrum that can result in various tissue injury disorders. Previous studies demonstrated that UVA, which represents 95% of incident photovoltaic radiation, induces corneal endothelial cells (CECs) death. Programmed cell death (PCD) has been implicated in numerous ophthalmologic diseases. Here, we investigated receptor-interacting protein 3 kinase (RIPK3), a key signaling molecule of PCD, in UVA-induced injury using a short-term corneal endothelium (CE) culture model. UVA irradiation activated RIPK3 and mediated necroptosis both in mouse CE and primary human CECs (pHCECs). UVA irradiation was associated with upregulation of key necroptotic molecules (DAI, TRIF, and MLKL) that lie downstream of RIPK3. Moreover, RIPK3 inhibition or silencing in primary corneal endothelial cells suppresses UVA-induced cell death, along with downregulation of MLKL in pHCECs. In addition, genetic inhibition or knockout of RIPK3 in mice (RIPK3K51A and RIPK3−/− mice) similarly attenuates cell death and the levels of necroptosis in ex vivo UVA irradiation experiments. In conclusion, these results identify RIPK3, not RIPK1, as a critical regulator of UVA-induced cell death in CE and indicate its potential as a future protective target.
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- 2021
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263. Local photoreceptor cell death differences in the murine model of retinal detachment
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Daniel E. Maidana, Lucia Gonzalez-Buendia, Joan W. Miller, and Demetrios G. Vavvas
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Medicine ,Science - Abstract
Abstract To investigate local cell death differences in the attached and detached retina at different regions in a murine experimental retinal detachment model. Subretinal injection of sodium hyaluronate was performed in eight-week-old C57BL/6J mice. Retinal regions of interest were defined in relation to their distance from the peak of the retinal detachment, as follows: (1) attached central; (2) attached paracentral; (3) detached apex; and (4) detached base. At day 0, the outer nuclear layer cell count for the attached central, attached paracentral, detached apex, and detached base was 1247.60 ± 64.62, 1157.80 ± 163.33, 1264.00 ± 150.7, and 1013.80 ± 67.16 cells, respectively. There were significant differences between the detached base vs. attached central, and between detached base vs. detached apex at day 0. The detached apex region displayed a significant and progressive cell count reduction from day 0 to 14. In contrast, the detached base region did not show progressive retinal degeneration in this model. Moreover, only the detached apex region had a significant and progressive cell death rate compared to baseline. Immediate confounding changes with dramatic differences in cell death rates are present across regions of the detached retina. We speculate that mechanical and regional differences in the bullous detached retina can modify the rate of cell death in this model.
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- 2021
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264. Opposing Roles of Blood-Borne Monocytes and Tissue-Resident Macrophages in Limbal Stem Cell Damage after Ocular Injury
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Chengxin Zhou, Fengyang Lei, Mirja Mittermaier, Bruce Ksander, Reza Dana, Claes H. Dohlman, Demetrios G. Vavvas, James Chodosh, and Eleftherios I. Paschalis
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limbal stem cell deficiency ,cornea ,epithelium ,macrophages ,monocytes ,inflammation ,Cytology ,QH573-671 - Abstract
Limbal stem cell (LSC) deficiency is a frequent and severe complication after chemical injury to the eye. Previous studies have assumed this is mediated directly by the caustic agent. Here we show that LSC damage occurs through immune cell mediators, even without direct injury to LSCs. In particular, pH elevation in the anterior chamber (AC) causes acute uveal stress, the release of inflammatory cytokines at the basal limbal tissue, and subsequent LSC damage and death. Peripheral C-C chemokine receptor type 2 positive/CX3C motif chemokine receptor 1 negative (CCR2+ CX3CR1−) monocytes are the key mediators of LSC damage through the upregulation of tumor necrosis factor-alpha (TNF-α) at the limbus. In contrast to peripherally derived monocytes, CX3CR1+ CCR2− tissue-resident macrophages have a protective role, and their depletion prior to injury exacerbates LSC loss and increases LSC vulnerability to TNF-α-mediated apoptosis independently of CCR2+ cell infiltration into the tissue. Consistently, repopulation of the tissue by new resident macrophages not only restores the protective M2-like phenotype of macrophages but also suppresses LSC loss after exposure to inflammatory signals. These findings may have clinical implications in patients with LSC loss after chemical burns or due to other inflammatory conditions.
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- 2023
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265. Sustained Inhibition of VEGF and TNF-α Achieves Multi-Ocular Protection and Prevents Formation of Blood Vessels after Severe Ocular Trauma
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Chengxin Zhou, Fengyang Lei, Jyoti Sharma, Pui-Chuen Hui, Natalie Wolkow, Claes H. Dohlman, Demetrios G. Vavvas, James Chodosh, and Eleftherios I. Paschalis
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cornea ,retina ,injury ,biologics ,VEFG ,TNF ,Pharmacy and materia medica ,RS1-441 - Abstract
Purpose: This study aimed to develop a clinically feasible and practical therapy for multi-ocular protection following ocular injury by using a thermosensitive drug delivery system (DDS) for sustained delivery of TNF-α and VEGF inhibitors to the eye. Methods: A thermosensitive, biodegradable hydrogel DDS (PLGA-PEG-PLGA triblock polymer) loaded with 0.7 mg of adalimumab and 1.4 mg of aflibercept was injected subconjunctivally into Dutch-belted pigmented rabbits after corneal alkali injury. Control rabbits received 2 mg of IgG-loaded DDS or 1.4 mg of aflibercept-loaded DDS. Animals were followed for 3 months and assessed for tolerability and prevention of corneal neovascularization (NV), improvement of corneal re-epithelialization, inhibition of retinal ganglion cell (RGC) and optic nerve axon loss, and inhibition of immune cell infiltration into the cornea. Drug-release kinetics was assessed in vivo using an aqueous humor protein analysis. Results: A single subconjunctival administration of dual anti-TNF-α/anti-VEGF DDS achieved a sustained 3-month delivery of antibodies to the anterior chamber, iris, ciliary body, and retina. Administration after corneal alkali burn suppressed CD45+ immune cell infiltration into the cornea, completely inhibited cornea NV for 3 months, accelerated corneal re-epithelialization and wound healing, and prevented RGC and optic nerve axon loss at 3 months. In contrast, anti-VEGF alone or IgG DDS treatment led to persistent corneal epithelial defect (combined: + immune cells into the cornea (combined: 28 ± 20; anti-VEGF: 730 ± 178; anti-IgG: 360 ± 186, cells/section), and significant loss of RGCs (combined: 2.7%; anti-VEGF: 63%; IgG: 45%) and optic nerve axons at 3 months. The aqueous humor protein analysis showed first-order release kinetics without adverse effects at the injection site. Conclusions: Concomitant inhibition of TNF-α and VEGF prevents corneal neovascularization and ameliorates subsequent irreversible damage to the retina and optic nerve after severe ocular injury. A single subconjunctival administration of this therapy, using a biodegradable, slow-release thermosensitive DDS, achieved the sustained elution of therapeutic levels of antibodies to all ocular tissues for 3 months. This therapeutic approach has the potential to dramatically improve the outcomes of severe ocular injuries in patients and improve the therapeutic outcomes in patients with retinal vascular diseases.
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- 2023
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266. Genomic-Metabolomic Associations Support the Role of LIPC and Glycerophospholipids in Age-Related Macular Degeneration
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Ines Lains, MD, PhD, Shujian Zhu, MSc, Xikun Han, PhD, Wonil Chung, PhD, Qianyu Yuan, PhD, Rachel S. Kelly, PhD, Joao Q. Gil, MD, Raviv Katz, BSc, Archana Nigalye, MD, Ivana K. Kim, MD, John B. Miller, MD, Isabel M. Carreira, PhD, Rufino Silva, MD, PhD, Demetrios G. Vavvas, MD, PhD, Joan W. Miller, MD, Jessica Lasky-Su, ScD, Liming Liang, PhD, and Deeba Husain, MD
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AMD ,Genetics ,Metabolomic-genomic associations ,Metabolomics ,Ophthalmology ,RE1-994 - Abstract
Purpose: Large-scale genome-wide association studies (GWAS) have reported important single nucleotide polymorphisms (SNPs) with significant associations with age-related macular degeneration (AMD). However, their role in disease development remains elusive. This study aimed to assess SNP–metabolite associations (i.e., metabolite quantitative trait loci [met-QTL]) and to provide insights into the biological mechanisms of AMD risk SNPs. Design: Cross-sectional multicenter study (Boston, Massachusetts, and Coimbra, Portugal). Participants: Patients with AMD (n = 388) and control participants (n = 98) without any vitreoretinal disease (> 50 years). Methods: Age-related macular degeneration grading was performed using color fundus photographs according to the Age-Related Eye Disease Study classification scheme. Fasting blood samples were collected and evaluated with mass spectrometry for metabolomic profiling and Illumina OmniExpress for SNPs profiling. Analyses of met-QTL of endogenous metabolites were conducted using linear regression models adjusted for age, gender, smoking, 10 metabolite principal components (PCs), and 10 SNP PCs. Additionally, we analyzed the cumulative effect of AMD risk SNPs on plasma metabolites by generating genetic risk scores and assessing their associations with metabolites using linear regression models, accounting for the same covariates. Modeling was performed first for each cohort, and then combined by meta-analysis. Multiple comparisons were accounted for using the false discovery rate (FDR). Main Outcome Measures: Plasma metabolite levels associated with AMD risk SNPs. Results: After quality control, data for 544 plasma metabolites were included. Meta-analysis of data from all individuals (AMD patients and control participants) identified 28 significant met-QTL (β = 0.016–0.083; FDR q-value < 1.14 × 10–2), which corresponded to 5 metabolites and 2 genes: ASPM and LIPC. Polymorphisms in the LIPC gene were associated with phosphatidylethanolamine metabolites, which are glycerophospholipids, and polymorphisms in the ASPM gene with branched-chain amino acids. Similar results were observed when considering only patients with AMD. Genetic risk score–metabolite associations further supported a global impact of AMD risk SNPs on the plasma metabolome. Conclusions: This study demonstrated that genomic–metabolomic associations can provide insights into the biological relevance of AMD risk SNPs. In particular, our results support that the LIPC gene and the glycerophospholipid metabolic pathway may play an important role in AMD, thus offering new potential therapeutic targets for this disease.
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- 2021
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267. Incidence of Endophthalmitis after Intravitreal Anti-Vascular Endothelial Growth Factor Injections in an Operating Room in China
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Yanyun Chen, Wenbin Wei, Demetrios G. Vavvas, Feng Zhang, Haicheng She, Haiying Zhou, Lei Li, Yao Huang, Dimitrios P. Ntentakis, and Xiangyu Shi
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Ophthalmology ,RE1-994 - Abstract
Purpose. To evaluate the rate of presumed endophthalmitis (EO) after intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections performed in an operating room (OR) under sterile conditions in mainland China. Methods. Retrospective single-center study between September 2012 and December 2017 at Beijing Tongren Eye Center, Beijing, China. Intravitreal injection database was reviewed. All anti-VEGF injections were performed using a standardized sterile technique in an OR. Injection protocols included antibiotics for 3 days pre-injection, topical 5% povidone-iodine rinsing before the procedure, and post-injection antibiotics for 3 days. Results. A total of 37,830 intravitreal injections were performed at Beijing Tongren Eye Center. Three cases were managed as presumed EO (0.0079%). Positive cultures were documented in 2 of 3 cases. EO incidence following ranibizumab and conbercept administration was 0.0088% (3 in 33,930) and 0% (0 in 3,900), respectively. No significant difference was detected between the two drugs (P=0.745). Conclusions. Very low EO rates were seen in mainland China using a standardized sterile technique in an OR. However, EO could not be completely avoided.
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- 2020
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268. Verteporfin inhibits growth of human glioma in vitro without light activation
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Ahmad Al-Moujahed, Katarzyna Brodowska, Tomasz P. Stryjewski, Nikolaos E. Efstathiou, Ioannis Vasilikos, Joanna Cichy, Joan W. Miller, Evangelos Gragoudas, and Demetrios G. Vavvas
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Medicine ,Science - Abstract
Abstract Verteporfin (VP), a light-activated drug used in photodynamic therapy for the treatment of choroidal neovascular membranes, has also been shown to be an effective inhibitor of malignant cells. Recently, studies have demonstrated that, even without photo-activation, VP may still inhibit certain tumor cell lines, including ovarian cancer, hepatocarcinoma and retinoblastoma, through the inhibition of the YAP-TEAD complex. In this study, we examined the effects of VP without light activation on human glioma cell lines (LN229 and SNB19). Through western blot analysis, we identified that human glioma cells that were exposed to VP without light activation demonstrated a downregulation of YAP-TEAD-associated downstream signaling molecules, including c-myc, axl, CTGF, cyr61 and survivin and upregulation of the tumor growth inhibitor molecule p38 MAPK. In addition, we observed that expression of VEGFA and the pluripotent marker Oct-4 were also decreased. Verteporfin did not alter the Akt survival pathway or the mTor pathway but there was a modest increase in LC3-IIB, a marker of autophagosome biogenesis. This study suggests that verteporfin should be further explored as an adjuvant therapy for the treatment of glioblastoma.
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- 2017
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269. Atorvastatin Promotes Phagocytosis and Attenuates Pro-Inflammatory Response in Human Retinal Pigment Epithelial Cells
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Bo Tian, Ahmad Al-Moujahed, Peggy Bouzika, Yijun Hu, Shoji Notomi, Pavlina Tsoka, Joan W. Miller, Haijiang Lin, and Demetrios G. Vavvas
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Medicine ,Science - Abstract
Abstract Phagocytosis of daily shed photoreceptor outer segments is an important function of the retinal pigment epithelium (RPE) and it is essential for retinal homeostasis. RPE dysfunction, especially impairment of its phagocytic ability, plays an essential role in the pathogenesis of age-related macular degeneration (AMD). Statins, or HMG CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase inhibitors, are drugs with multiple properties that have been extensively used to treat hyperlipidemia. However, their effect on RPE cells has not been fully elucidated. Here we report that high dose atorvastatin increased the phagocytic function of ARPE-19 cells, as well as rescue the cells from the phagocytic dysfunction induced by cholesterol crystals and oxidized low-density lipoproteins (ox-LDL), potentially by increasing the cellular membrane fluidity. Similar effects were observed when evaluating two other hydrophobic statins, lovastatin and simvastatin. Furthermore, atorvastatin was able to block the induction of interleukins IL-6 and IL-8 triggered by pathologic stimuli relevant to AMD, such as cholesterol crystals and ox-LDL. Our study shows that statins, a well-tolerated class of drugs with rare serious adverse effects, help preserve the phagocytic function of the RPE while also exhibiting anti-inflammatory properties. Both characteristics make statins a potential effective medication for the prevention and treatment of AMD.
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- 2017
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270. RETRACTED ARTICLE: Verteporfin-induced formation of protein cross-linked oligomers and high molecular weight complexes is mediated by light and leads to cell toxicity
- Author
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Eleni K. Konstantinou, Shoji Notomi, Cassandra Kosmidou, Katarzyna Brodowska, Ahmad Al-Moujahed, Fotini Nicolaou, Pavlina Tsoka, Evangelos Gragoudas, Joan W. Miller, Lucy H. Young, and Demetrios G. Vavvas
- Subjects
Medicine ,Science - Abstract
Abstract Verteporfin (VP) was first used in Photodynamic therapy, where a non-thermal laser light (689 nm) in the presence of oxygen activates the drug to produce highly reactive oxygen radicals, resulting in local cell and tissue damage. However, it has also been shown that Verteporfin can have non-photoactivated effects such as interference with the YAP-TEAD complex of the HIPPO pathway, resulting in growth inhibition of several neoplasias. More recently, it was proposed that, another non-light mediated effect of VP is the formation of cross-linked oligomers and high molecular weight protein complexes (HMWC) that are hypothesized to interfere with autophagy and cell growth. Here, in a series of experiments, using human uveal melanoma cells (MEL 270), human embryonic kidney cells (HEK) and breast cancer cells (MCF7) we showed that Verteporfin-induced HMWC require the presence of light. Furthermore, we showed that the mechanism of this cross-linking, which involves both singlet oxygen and radical generation, can occur very efficiently even after lysis of the cells, if the lysate is not protected from ambient light. This work offers a better understanding regarding VP’s mechanisms of action and suggests caution when one studies the non-light mediated actions of this drug.
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- 2017
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271. Receptor interacting protein kinase 3 (RIP3) regulates iPSCs generation through modulating cell cycle progression genes
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Ahmad Al-Moujahed, Bo Tian, Nikolaos E. Efstathiou, Eleni K. Konstantinou, Mien Hoang, Haijiang Lin, Joan W. Miller, and Demetrios G. Vavvas
- Subjects
Biology (General) ,QH301-705.5 - Abstract
The molecular mechanisms involved in induced pluripotent stem cells (iPSCs) generation are poorly understood. The cell death machinery of apoptosis-inducing caspases have been shown to facilitate the process of iPSCs reprogramming. However, the effect of other cell death processes, such as programmed necrosis (necroptosis), on iPSCs induction has not been studied. In this study, we investigated the role of receptor-interacting protein kinase 3 (RIP3), an essential regulator of necroptosis, in reprogramming mouse embryonic fibroblast cells (MEFs) into iPSCs. RIP3 was found to be upregulated in iPSCs compared to MEFs. Deletion of RIP3 dramatically suppressed the reprogramming of iPSCs (~82%). RNA-seq analysis and qRT-PCR showed that RIP3 KO MEFs expressed lower levels of genes that control cell cycle progression and cell division and higher levels of extracellular matrix-regulating genes. The growth rate of RIP3 KO MEFs was significantly slower than WT MEFs. These findings can partially explain the inhibitory effects of RIP3 deletion on iPSCs generation and show for the first time that the necroptosis kinase RIP3 plays an important role in iPSC reprogramming. In contrast to RIP3, the kinase and scaffolding functions of RIPK1 appeared to have distinct effects on reprogramming. Keywords: Reprogramming, Programmed necrosis, Necroptosis, Cell death, RIPK3, RIPK, RIP
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- 2019
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272. Association of Human Plasma Metabolomics with Delayed Dark Adaptation in Age-Related Macular Degeneration
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Kevin M. Mendez, Janice Kim, Inês Laíns, Archana Nigalye, Raviv Katz, Shrinivas Pundik, Ivana K. Kim, Liming Liang, Demetrios G. Vavvas, John B. Miller, Joan W. Miller, Jessica A. Lasky-Su, and Deeba Husain
- Subjects
age-related macular degeneration ,dark adaptation ,rod-intercept time ,area under the dark adaption curve ,metabolomics ,mass spectrometry ,Microbiology ,QR1-502 - Abstract
The purpose of this study was to analyze the association between plasma metabolite levels and dark adaptation (DA) in age-related macular degeneration (AMD). This was a cross-sectional study including patients with AMD (early, intermediate, and late) and control subjects older than 50 years without any vitreoretinal disease. Fasting blood samples were collected and used for metabolomic profiling with ultra-performance liquid chromatography–mass spectrometry (LC-MS). Patients were also tested with the AdaptDx (MacuLogix, Middletown, PA, USA) DA extended protocol (20 min). Two measures of dark adaptation were calculated and used: rod-intercept time (RIT) and area under the dark adaptation curve (AUDAC). Associations between dark adaption and metabolite levels were tested using multilevel mixed-effects linear modelling, adjusting for age, gender, body mass index (BMI), smoking, race, AMD stage, and Age-Related Eye Disease Study (AREDS) formulation supplementation. We included a total of 71 subjects: 53 with AMD (13 early AMD, 31 intermediate AMD, and 9 late AMD) and 18 controls. Our results revealed that fatty acid-related lipids and amino acids related to glutamate and leucine, isoleucine and valine metabolism were associated with RIT (p < 0.01). Similar results were found when AUDAC was used as the outcome. Fatty acid-related lipids and amino acids are associated with DA, thus suggesting that oxidative stress and mitochondrial dysfunction likely play a role in AMD and visual impairment in this condition.
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- 2021
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273. Regression of Some High-risk Features of Age-related Macular Degeneration (AMD) in Patients Receiving Intensive Statin Treatment
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Demetrios G. Vavvas, Anthony B. Daniels, Zoi G. Kapsala, Jeremy W. Goldfarb, Emmanuel Ganotakis, John I. Loewenstein, Lucy H. Young, Evangelos S. Gragoudas, Dean Eliott, Ivana K. Kim, Miltiadis K. Tsilimbaris, and Joan W. Miller
- Subjects
AMD ,Statins ,High-dose ,Reversal ,Soft-drusen ,Vision gain ,Medicine ,Medicine (General) ,R5-920 - Abstract
Importance: Age-related macular degeneration (AMD) remains the leading cause of blindness in developed countries, and affects more than 150 million worldwide. Despite effective anti-angiogenic therapies for the less prevalent neovascular form of AMD, treatments are lacking for the more prevalent dry form. Similarities in risk factors and pathogenesis between AMD and atherosclerosis have led investigators to study the effects of statins on AMD incidence and progression with mixed results. A limitation of these studies has been the heterogeneity of AMD disease and the lack of standardization in statin dosage. Objective: We were interested in studying the effects of high-dose statins, similar to those showing regression of atherosclerotic plaques, in AMD. Design: Pilot multicenter open-label prospective clinical study of 26 patients with diagnosis of AMD and the presence of many large, soft drusenoid deposits. Patients received 80 mg of atorvastatin daily and were monitored at baseline and every 3 months with complete ophthalmologic exam, best corrected visual acuity (VA), fundus photographs, optical coherence tomography (OCT), and blood work (AST, ALT, CPK, total cholesterol, TSH, creatinine, as well as a pregnancy test for premenopausal women). Results: Twenty-three subjects completed a minimum follow-up of 12 months. High-dose atorvastatin resulted in regression of drusen deposits associated with vision gain (+3.3 letters, p = 0.06) in 10 patients. No subjects progressed to advanced neovascular AMD. Conclusions: High-dose statins may result in resolution of drusenoid pigment epithelial detachments (PEDs) and improvement in VA, without atrophy or neovascularization in a high-risk subgroup of AMD patients. Confirmation from larger studies is warranted.
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- 2016
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274. Human Plasma Metabolomics in Age-Related Macular Degeneration: Meta-Analysis of Two Cohorts
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Inês Laíns, Wonil Chung, Rachel S. Kelly, João Gil, Marco Marques, Patrícia Barreto, Joaquim N. Murta, Ivana K. Kim, Demetrios G. Vavvas, John B. Miller, Rufino Silva, Jessica Lasky-Su, Liming Liang, Joan W. Miller, and Deeba Husain
- Subjects
age-related macular degeneration ,metabolomics ,mass spectrometry ,Microbiology ,QR1-502 - Abstract
The pathogenesis of age-related macular degeneration (AMD), a leading cause of blindness worldwide, remains only partially understood. This has led to the current lack of accessible and reliable biofluid biomarkers for diagnosis and prognosis, and absence of treatments for dry AMD. This study aimed to assess the plasma metabolomic profiles of AMD and its severity stages with the ultimate goal of contributing to addressing these needs. We recruited two cohorts: Boston, United States (n = 196) and Coimbra, Portugal (n = 295). Fasting blood samples were analyzed using ultra-high performance liquid chromatography mass spectrometry. For each cohort, we compared plasma metabolites of AMD patients versus controls (logistic regression), and across disease stages (permutation-based cumulative logistic regression considering both eyes). Meta-analyses were then used to combine results from the two cohorts. Our results revealed that 28 metabolites differed significantly between AMD patients versus controls (false discovery rate (FDR) q-value: 4.1 × 10−2−1.8 × 10−5), and 67 across disease stages (FDR q-value: 4.5 × 10−2−1.7 × 10−4). Pathway analysis showed significant enrichment of glycerophospholipid, purine, taurine and hypotaurine, and nitrogen metabolism (p-value ≤ 0.04). In conclusion, our findings support that AMD patients present distinct plasma metabolomic profiles, which vary with disease severity. This work contributes to the understanding of AMD pathophysiology, and can be the basis of future biomarkers and precision medicine for this blinding condition.
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- 2019
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275. Optic Disk Pit with Sudden Central Visual Field Scotoma
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Nikol Panou and Demetrios G. Vavvas
- Subjects
Ophthalmology ,RE1-994 - Abstract
Purpose. To describe a case of optic disk pit (ODP) with sudden central visual field scotoma. Methods. A 49-year-old woman presented, reporting sudden painless central visual field loss 3 months prior to presentation. Neuroophthalmologic, systematic, and laboratory evaluation and full imaging processes were performed. Results. Fundoscopy and color photography demonstrated an optic disk pit inferotemporally. Perimetry identified central visual field horizontal scotoma. OCT revealed absence of serous retinal detachment, but disclosed inner retina thinning corresponding to the area of the visual field loss. Fluorescein angiography demonstrated delay in the cilioretinal arteries and also disclosed a relative delay in the perfusion of an arterial branch off the inferior retinal arcade. Clinical and laboratory evaluations were negative for any related pathology. Conclusion. Sudden central visual field scotoma in patients with ODP may be associated with delayed vascular filling of CRA and retinal arterioles within the optic disc anomaly region.
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- 2016
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276. Mechanisms of Inflammation in Proliferative Vitreoretinopathy: From Bench to Bedside
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Stavros N. Moysidis, Aristomenis Thanos, and Demetrios G. Vavvas
- Subjects
Pathology ,RB1-214 - Abstract
Proliferative vitreoretinopathy (PVR) is a vision-threatening disease and a common complication of surgery to correct rhegmatogenous retinal detachment (RRD). Several models of the pathogenesis of this disease have been described with some of these models focusing on the role of inflammatory cells and other models focusing on the role of growth factors and cytokines in the vitreous which come into contact with intraretinal and retinal pigment epithelial cells. New experiments have shed light on the pathogenesis of PVR and offer promising avenues for clinical intervention before PVR develops. One such target is the indirect pathway of activation of platelet-derived growth factor receptor alpha (PDGRα), which plays an important role in PVR. Clinical trials assessing the efficacy of 5-fluorouracil (5-FU) and low-molecular-weight heparin (LMWH), daunorubicin, and 13-cis-retinoic acid, among other therapies, have yielded mixed results. Here we review inflammatory and other mechanisms involved in the pathogenesis of PVR, we highlight important clinical trials, and we discuss how findings at the bench have the potential to be translated to the bedside.
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- 2012
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