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Nguyen Y, Rudd Zhong Manis J, Ronczkowski NM, Bui T, Oxenrider A, Jadeja RN, Thounaojam MC. Unveiling the gut-eye axis: how microbial metabolites influence ocular health and disease. Front Med (Lausanne) 2024; 11:1377186. [PMID: 38799150 PMCID: PMC11122920 DOI: 10.3389/fmed.2024.1377186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/19/2024] [Indexed: 05/29/2024] Open
Abstract
The intricate interplay between the gut microbiota and ocular health has surpassed conventional medical beliefs, fundamentally reshaping our understanding of organ interconnectivity. This review investigates into the intricate relationship between gut microbiota-derived metabolites and their consequential impact on ocular health and disease pathogenesis. By examining the role of specific metabolites, such as short-chain fatty acids (SCFAs) like butyrate and bile acids (BAs), herein we elucidate their significant contributions to ocular pathologies, thought-provoking the traditional belief of organ sterility, particularly in the field of ophthalmology. Highlighting the dynamic nature of the gut microbiota and its profound influence on ocular health, this review underlines the necessity of comprehending the complex workings of the gut-eye axis, an emerging field of science ready for further exploration and scrutiny. While acknowledging the therapeutic promise in manipulating the gut microbiome and its metabolites, the available literature advocates for a targeted, precise approach. Instead of broad interventions, it emphasizes the potential of exploiting specific microbiome-related metabolites as a focused strategy. This targeted approach compared to a precision tool rather than a broad-spectrum solution, aims to explore the therapeutic applications of microbiome-related metabolites in the context of various retinal diseases. By proposing a nuanced strategy targeted at specific microbial metabolites, this review suggests that addressing specific deficiencies or imbalances through microbiome-related metabolites might yield expedited and pronounced outcomes in systemic health, extending to the eye. This focused strategy holds the potential in bypassing the irregularity associated with manipulating microbes themselves, paving a more efficient pathway toward desired outcomes in optimizing gut health and its implications for retinal diseases.
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Affiliation(s)
- Yvonne Nguyen
- Mercer University School of Medicine, Macon, GA, United States
| | | | | | - Tommy Bui
- Departments of Cellular Biology and Anatomy, Augusta University, Augusta, GA, United States
| | - Allston Oxenrider
- Departments of Cellular Biology and Anatomy, Augusta University, Augusta, GA, United States
| | - Ravirajsinh N. Jadeja
- Biochemistry and Molecular Biology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Menaka C. Thounaojam
- Departments of Cellular Biology and Anatomy, Augusta University, Augusta, GA, United States
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Ionescu CM, Kovacevic B, Jones MA, Wagle SR, Foster T, Mikov M, Mooranian A, Al-Salami H. Probucol-Ursodeoxycholic Acid Otic Formulations: Stability and In Vitro Assessments for Hearing Loss Treatment. J Pharm Sci 2024:S0022-3549(24)00159-X. [PMID: 38734207 DOI: 10.1016/j.xphs.2024.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024]
Abstract
Targeted drug delivery is an ongoing aspect of scientific research that is expanding through the design of micro- and nanoparticles. In this paper, we focus on spray dried microparticles as carriers for a repurposed lipophilic antioxidant (probucol). We characterise the microparticles and quantify probucol prior to assessing cytotoxicity on both control and cisplatin treated hair cells (known as House Ear Institute-Organ of Corti 1; HEI-OC1). The addition of water-soluble polymers to 2% β-cyclodextrin resulted in a stable probucol formulation. Ursodeoxycholic acid (UDCA) used as formulation excipient increases probucol miscibility and microparticle drug content. Formulation characterisations reveals spray drying results in spherical UDCA-drug microparticles with a mean size distribution of ∼5-12 μm. Probucol microparticles show stable short-term storage conditions accounting for only ∼10% loss over seven days. By mimicking cell culture conditions, both UDCA-probucol (67%) and probucol only (82%) microparticles show drug release in the initial two hours. Furthermore, probucol formulations with or without UDCA preserve cell viability and reduce cisplatin-induced oxidative stress. Mitochondrial bioenergetics results in lower basal respiration and non-mitochondrial respiration, with higher maximal respiration, spare capacity, ATP production and proton leak within cisplatin challenged UDCA-probucol groups. Overall, we present a facile method for incorporating lipophilic antioxidant carriers in polymer-based particles that are tolerated by HEI-OC1 cells and show stable drug release, sufficient in reducing cisplatin-induced reactive oxygen species accumulation.
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Affiliation(s)
- Corina M Ionescu
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia, Australia
| | - Bozica Kovacevic
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia, Australia
| | - Melissa A Jones
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia, Australia
| | - Susbin R Wagle
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia, Australia
| | - Thomas Foster
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia, Australia
| | - Momir Mikov
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Armin Mooranian
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia, Australia; School of Pharmacy, University of Otago, Dunedin, Otago, New Zealand.
| | - Hani Al-Salami
- The Biotechnology and Drug Development Research Laboratory, Curtin Medical School & Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia, Australia; Medical School, University of Western Australia, Perth, Western Australia, Australia.
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Takase K, Yokota H, Ohno A, Watanabe M, Kushiyama A, Kushiyama S, Yamagami S, Nagaoka T. A pilot study of diabetic retinopathy in a porcine model of maturity onset diabetes of the young type 3 (MODY3). Exp Eye Res 2023; 227:109379. [PMID: 36608813 DOI: 10.1016/j.exer.2022.109379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 01/05/2023]
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness in the working population. Because novel therapeutic intervention require testing, there is an urgent need for reliable animal models that faithfully replicate DR. Pig eyes have many similarities to human eyes anatomically and physiologically. Thus, attempts have been made to establish porcine models of DR by surgical, pharmaceutical or genetical induction of insulin deficiency, and dietary intervention. A previous study reported a transgenic pig model of maturity onset diabetes of the young type 3 (MODY3) developed signs of severe DR such as hemorrhage and proliferative tissue at the surface of the retina. However, the course of development of DR has not been studied in detail in this model. The purpose of this study was to investigate the early phase of DR in a MODY3. MODY3 and wild-type (WT) pigs underwent fundus photography and fluorescein angiogram (FA) before they developed cataracts. Animals were euthanized at age 1, 4, 7, and 10 months. Whole-mount retina and 10-μm thick paraffinized sections were stained with isolectin B4, and vessel density was determined by MATLAB software. At 4 and 7 months, retinal arterioles were immediately cannulated, and vasomotor action was measured by incubation with bradykinin and sodium nitroprusside. In the MODY3 pigs, fasting blood sugar levels gradually increased up to 500 mg/dL. Vascular tortuosity and yellowish spindle-shaped lesions were confirmed in MODY3 pigs at the age of 7 months; however, no microaneurysms were detected on FA. Compared with age-matched WT pigs, MODY3 pigs showed a significant decrease in blood vessel density in the intermediate and deep vascular plexus at 4 and 7 months of age and a slight decrease in capillary density in the superficial vascular plexus at 7 months of age. In MODY3 pigs, electron microscopy revealed thickening of the capillary basement membrane and leukostasis in the major blood vessels at 10 months of age. Bradykinin-induced dilation of retinal arterioles was diminished in MODY3 pigs as early as 7 months of age. Within 1 year after birth, MODY3 pigs show all typical early vascular lesions of diabetes except for microaneurysm formation. This pilot study suggests that the MODY3 pigs may serve as a suitable DR model to test effects of newly developed compounds on DR.
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Affiliation(s)
- Koyo Takase
- Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
| | - Harumasa Yokota
- Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan.
| | - Akira Ohno
- Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
| | - Masahisa Watanabe
- Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
| | - Akifumi Kushiyama
- Department of Pharmacotherapy, Meiji Pharmaceutical University, Kiyose, Tokyo, 204-8588, Japan
| | - Sakura Kushiyama
- Division of Life Science, Department of Nursing, National College of Nursing, Kiyose, Tokyo, 204-8575, Japan
| | - Satoru Yamagami
- Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
| | - Taiji Nagaoka
- Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
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Glycine-Conjugated Bile Acids Protect RPE Tight Junctions against Oxidative Stress and Inhibit Choroidal Endothelial Cell Angiogenesis In Vitro. Biomolecules 2021; 11:biom11050626. [PMID: 33922434 PMCID: PMC8146504 DOI: 10.3390/biom11050626] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/15/2021] [Accepted: 04/21/2021] [Indexed: 02/07/2023] Open
Abstract
We previously demonstrated that the bile acid taurocholic acid (TCA) inhibits features of age-related macular degeneration (AMD) in vitro. The purpose of this study was to determine if the glycine-conjugated bile acids glycocholic acid (GCA), glycodeoxycholic acid (GDCA), and glycoursodeoxycholic acid (GUDCA) can protect retinal pigment epithelial (RPE) cells against oxidative damage and inhibit vascular endothelial growth factor (VEGF)-induced angiogenesis in choroidal endothelial cells (CECs). Paraquat was used to induce oxidative stress and disrupt tight junctions in HRPEpiC primary human RPE cells. Tight junctions were assessed via transepithelial electrical resistance and ZO-1 immunofluorescence. GCA and GUDCA protected RPE tight junctions against oxidative damage at concentrations of 100–500 µM, and GDCA protected tight junctions at 10–500 µM. Angiogenesis was induced with VEGF in RF/6A macaque CECs and evaluated with cell proliferation, cell migration, and tube formation assays. GCA inhibited VEGF-induced CEC migration at 50–500 µM and tube formation at 10–500 µM. GUDCA inhibited VEGF-induced CEC migration at 100–500 µM and tube formation at 50–500 µM. GDCA had no effect on VEGF-induced angiogenesis. None of the three bile acids significantly inhibited VEGF-induced CEC proliferation. These results suggest glycine-conjugated bile acids may be protective against both atrophic and neovascular AMD.
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Win A, Delgado A, Jadeja RN, Martin PM, Bartoli M, Thounaojam MC. Pharmacological and Metabolic Significance of Bile Acids in Retinal Diseases. Biomolecules 2021; 11:biom11020292. [PMID: 33669313 PMCID: PMC7920062 DOI: 10.3390/biom11020292] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/10/2021] [Accepted: 02/13/2021] [Indexed: 12/21/2022] Open
Abstract
Bile acids (BAs) are amphipathic sterols primarily synthesized from cholesterol in the liver and released in the intestinal lumen upon food intake. BAs play important roles in micellination of dietary lipids, stimulating bile flow, promoting biliary phospholipid secretion, and regulating cholesterol synthesis and elimination. Emerging evidence, however, suggests that, aside from their conventional biological function, BAs are also important signaling molecules and therapeutic tools. In the last decade, the therapeutic applications of BAs in the treatment of ocular diseases have gained great interest. Despite the identification of BA synthesis, metabolism, and recycling in ocular tissues, much remains unknown with regards to their biological significance in the eye. Additionally, as gut microbiota directly affects the quality of circulating BAs, their analysis could derive important information on changes occurring in this microenvironment. This review aims at providing an overview of BA metabolism and biological function with a focus on their potential therapeutic and diagnostic use for retinal diseases.
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Affiliation(s)
- Alice Win
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; (A.W.); (A.D.); (P.M.M.); (M.B.)
| | - Amanda Delgado
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; (A.W.); (A.D.); (P.M.M.); (M.B.)
| | - Ravirajsinh N. Jadeja
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
- James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Pamela M. Martin
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; (A.W.); (A.D.); (P.M.M.); (M.B.)
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
- James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Manuela Bartoli
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; (A.W.); (A.D.); (P.M.M.); (M.B.)
- James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Menaka C. Thounaojam
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; (A.W.); (A.D.); (P.M.M.); (M.B.)
- James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Correspondence: ; Tel.: +706-721-9163 or +706-721-7910; Fax: +706-721-9799
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