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Wu J, Jo DH, Fruttiger M, Kim JH. Cone cell dysfunction attenuates retinal neovascularization in oxygen-induced retinopathy mouse model. J Neurosci Res 2024; 102:e25316. [PMID: 38415926 DOI: 10.1002/jnr.25316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/21/2024] [Accepted: 02/19/2024] [Indexed: 02/29/2024]
Abstract
Aberrant neovascularization is the most common feature in retinopathy of prematurity (ROP), which leads to the retinal detachment and visual defects in neonates with a low gestational age eventually. Understanding the regulation of inappropriate angiogenic signaling benefits individuals at-risk. Recently, neural activity originating from the specific neural activity has been considered to contribute to retinal angiogenesis. Here, we explored the impact of cone cell dysfunction on oxygen-induced retinopathy (OIR), a mouse model commonly employed to understand retinal diseases associated with abnormal blood vessel growth, using the Gnat2cpfl3 (cone photoreceptor function loss-3) strain of mice (regardless of the sex), which is known for its inherent cone cell dysfunction. We found that the retinal avascular area, hypoxic area, and neovascular area were significantly attenuated in Gnat2cpfl3 OIR mice compared to those in C57BL/6 OIR mice. Moreover, the HIF-1α/VEGF axis was also reduced in Gnat2cpfl3 OIR mice. Collectively, our results indicated that cone cell dysfunction, as observed in Gnat2cpfl3 OIR mice, leads to attenuated retinal neovascularization. This finding suggests that retinal neural activity may precede and potentially influence the onset of pathological neovascularization.
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Affiliation(s)
- Jun Wu
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong Hyun Jo
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Marcus Fruttiger
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Global Excellence Center for Gene & Cell Therapy (GEC-GCT), Seoul National University Hospital, Seoul, Republic of Korea
- Institute of Reproductive Medicine and Population, Seoul National University College of Medicine, Seoul, Republic of Korea
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2
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Harman JC, Pivodic A, Nilsson AK, Boeck M, Yagi H, Neilsen K, Ko M, Yang J, Kinter M, Hellström A, Fu Z. Postnatal hyperglycemia alters amino acid profile in retinas (model of Phase I ROP). iScience 2023; 26:108021. [PMID: 37841591 PMCID: PMC10568433 DOI: 10.1016/j.isci.2023.108021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/03/2023] [Accepted: 09/19/2023] [Indexed: 10/17/2023] Open
Abstract
Nutritional deprivation occurring in most preterm infants postnatally can induce hyperglycemia, a significant and independent risk factor for suppressing physiological retinal vascularization (Phase I retinopathy of prematurity (ROP)), leading to compensatory but pathological neovascularization. Amino acid supplementation reduces retinal neovascularization in mice. Little is known about amino acid contribution to Phase I ROP. In mice modeling hyperglycemia-associated Phase I ROP, we found significant changes in retinal amino acids (including most decreased L-leucine, L-isoleucine, and L-valine). Parenteral L-isoleucine suppressed physiological retinal vascularization. In premature infants, severe ROP was associated with a higher mean intake of parenteral versus enteral amino acids in the first two weeks of life after adjustment for treatment group, gestational age at birth, birth weight, and sex. The number of days with parenteral amino acids support independently predicted severe ROP. Further understanding and modulating amino acids may help improve nutritional intervention and prevent Phase I ROP.
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Affiliation(s)
- Jarrod C. Harman
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Aldina Pivodic
- The Sahlgrenska Centre for Pediatric Ophthalmology Research, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anders K. Nilsson
- The Sahlgrenska Centre for Pediatric Ophthalmology Research, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Myriam Boeck
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Hitomi Yagi
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Ophthalmology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Katherine Neilsen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Minji Ko
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jay Yang
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Michael Kinter
- Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Ann Hellström
- The Sahlgrenska Centre for Pediatric Ophthalmology Research, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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3
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Abstract
Retinopathy of prematurity (ROP) is a complex disease involving development of the neural retina, ocular circulations, and other organ systems of the premature infant. The external stresses of the ex utero environment also influence the pathophysiology of ROP through interactions among retinal neural, vascular, and glial cells. There is variability among individual infants and presentations of the disease throughout the world, making ROP challenging to study. The methods used include representative animal models, cell culture, and clinical studies. This article describes the impact of maternal-fetal interactions; stresses that the preterm infant experiences; and biologic pathways of interest, including growth factor effects and cell-cell interactions, on the complex pathophysiology of ROP phenotypes in developed and emerging countries.
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Liu J, Tsang JKW, Fung FKC, Chung SK, Fu Z, Lo ACY. Retinal microglia protect against vascular damage in a mouse model of retinopathy of prematurity. Front Pharmacol 2022; 13:945130. [PMID: 36059936 PMCID: PMC9431881 DOI: 10.3389/fphar.2022.945130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/11/2022] [Indexed: 11/25/2022] Open
Abstract
Retinopathy of prematurity (ROP) is a common cause of blindness in preterm babies. As a hypoxia-induced eye disease characterized by neovascularization, its association with retinal microglia has been noted but not well documented. We performed a comprehensive analysis of retinal microglia and retinal vessels in mouse oxygen-induced retinopathy (OIR), an animal model of ROP. In combination with a pharmacological inhibitory strategy, the role of retinal microglia in vascular network maintenance was investigated. Postnatal day (P) 7 C57BL/6J mouse pups with their nursing mother were exposed to 75% oxygen for 5 days to induce OIR. Age-matched room air-treated pups served as controls. On P12, P17, P21, P25, and P30, retinal microglia and vessels were visualized and quantified based on their location and activation status. Their relationship with retinal vessels was also analyzed. On P5 or P12, retinal microglia inhibition was achieved by intravitreal injection of liposomes containing clodronate (CLD); retinal vasculature and microglia were examined in P12 and P17 OIR retinae. The number of retinal microglia was increased in the superficial areas of OIR retinae on P12, P17, P21, P25, and P30, and most of them displayed an amoeboid (activated) morphology. The increased retinal microglia were associated with increased superficial retinal vessels in OIR retinae. The number of retinal microglia in deep retinal areas of OIR retinae also increased from P17 to P30 with a ramified morphology, which was not associated with reduced retinal vessels. Intravitreal injection of liposomes-CLD caused a significant reduction in retinal microglia. Loss of retinal microglia before hyperoxia treatment resulted in increased vessel obliteration on P12 and subsequent neovascularization on P17 in OIR retinae. Meanwhile, loss of retinal microglia immediately after hyperoxia treatment on P12 also led to more neovascularization in P17 OIR retinae. Our data showed that activated microglia were strongly associated with vascular abnormalities upon OIR. Retinal microglial activation continued throughout OIR and lasted until after retinal vessel recovery. Pharmacological inhibition of retinal microglia in either hyperoxic or hypoxic stage of OIR exacerbated retinal vascular consequences. These results suggested that retinal microglia may play a protective role in retinal vasculature maintenance in the OIR process.
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Affiliation(s)
- Jin Liu
- Department of Ophthalmology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Jessica Kwan Wun Tsang
- Department of Ophthalmology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Frederic Khe Cheong Fung
- Department of Ophthalmology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Sookja Kim Chung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- *Correspondence: Zhongjie Fu, ; Amy Cheuk Yin Lo,
| | - Amy Cheuk Yin Lo
- Department of Ophthalmology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
- *Correspondence: Zhongjie Fu, ; Amy Cheuk Yin Lo,
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5
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Fu Z, Yan W, Chen CT, Nilsson AK, Bull E, Allen W, Yang J, Ko M, SanGiovanni JP, Akula JD, Talukdar S, Hellström A, Smith LEH. Omega-3/Omega-6 Long-Chain Fatty Acid Imbalance in Phase I Retinopathy of Prematurity. Nutrients 2022; 14:1333. [PMID: 35405946 PMCID: PMC9002570 DOI: 10.3390/nu14071333] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 11/17/2022] Open
Abstract
There is a gap in understanding the effect of the essential ω-3 and ω-6 long-chain polyunsaturated fatty acids (LCPUFA) on Phase I retinopathy of prematurity (ROP), which precipitates proliferative ROP. Postnatal hyperglycemia contributes to Phase I ROP by delaying retinal vascularization. In mouse neonates with hyperglycemia-associated Phase I retinopathy, dietary ω-3 (vs. ω-6 LCPUFA) supplementation promoted retinal vessel development. However, ω-6 (vs. ω-3 LCPUFA) was also developmentally essential, promoting neuronal growth and metabolism as suggested by a strong metabolic shift in almost all types of retinal neuronal and glial cells identified with single-cell transcriptomics. Loss of adiponectin (APN) in mice (mimicking the low APN levels in Phase I ROP) decreased LCPUFA levels (including ω-3 and ω-6) in retinas under normoglycemic and hyperglycemic conditions. ω-3 (vs. ω-6) LCPUFA activated the APN pathway by increasing the circulating APN levels and inducing expression of the retinal APN receptor. Our findings suggested that both ω-3 and ω-6 LCPUFA are crucial in protecting against retinal neurovascular dysfunction in a Phase I ROP model; adequate ω-6 LCPUFA levels must be maintained in addition to ω-3 supplementation to prevent retinopathy. Activation of the APN pathway may further enhance the ω-3 and ω-6 LCPUFA's protection against ROP.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (E.B.); (W.A.); (J.Y.); (M.K.); (J.D.A.)
| | - Wenjun Yan
- Center for Brain Science, Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA;
| | - Chuck T. Chen
- Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD 20814, USA;
| | - Anders K. Nilsson
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 412 96 Gothenburg, Sweden; (A.K.N.); (A.H.)
| | - Edward Bull
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (E.B.); (W.A.); (J.Y.); (M.K.); (J.D.A.)
| | - William Allen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (E.B.); (W.A.); (J.Y.); (M.K.); (J.D.A.)
| | - Jay Yang
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (E.B.); (W.A.); (J.Y.); (M.K.); (J.D.A.)
| | - Minji Ko
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (E.B.); (W.A.); (J.Y.); (M.K.); (J.D.A.)
| | - John Paul SanGiovanni
- BIO5 Institute, Department of Nutritional Sciences, The University of Arizona, Tucson, AZ 85721, USA;
| | - James D. Akula
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (E.B.); (W.A.); (J.Y.); (M.K.); (J.D.A.)
| | - Saswata Talukdar
- Cardiometabolic Diseases, Merck Research Laboratories, Boston, MA 02115, USA;
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 412 96 Gothenburg, Sweden; (A.K.N.); (A.H.)
| | - Lois E. H. Smith
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (E.B.); (W.A.); (J.Y.); (M.K.); (J.D.A.)
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Tomita Y, Usui-Ouchi A, Nilsson AK, Yang J, Ko M, Hellström A, Fu Z. Metabolism in Retinopathy of Prematurity. Life (Basel) 2021; 11:life11111119. [PMID: 34832995 PMCID: PMC8620873 DOI: 10.3390/life11111119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/11/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
Retinopathy of prematurity is defined as retinal abnormalities that occur during development as a consequence of disturbed oxygen conditions and nutrient supply after preterm birth. Both neuronal maturation and retinal vascularization are impaired, leading to the compensatory but uncontrolled retinal neovessel growth. Current therapeutic interventions target the hypoxia-induced neovessels but negatively impact retinal neurons and normal vessels. Emerging evidence suggests that metabolic disturbance is a significant and underexplored risk factor in the disease pathogenesis. Hyperglycemia and dyslipidemia correlate with the retinal neurovascular dysfunction in infants born prematurely. Nutritional and hormonal supplementation relieve metabolic stress and improve retinal maturation. Here we focus on the mechanisms through which metabolism is involved in preterm-birth-related retinal disorder from clinical and experimental investigations. We will review and discuss potential therapeutic targets through the restoration of metabolic responses to prevent disease development and progression.
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Affiliation(s)
- Yohei Tomita
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
| | - Ayumi Usui-Ouchi
- Department of Ophthalmology, Juntendo University Urayasu Hospital, Chiba 279-0021, Japan;
| | - Anders K. Nilsson
- Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 413 19 Gothenburg, Sweden; (A.K.N.); (A.H.)
| | - Jay Yang
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
| | - Minji Ko
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
| | - Ann Hellström
- Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 413 19 Gothenburg, Sweden; (A.K.N.); (A.H.)
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
- Correspondence:
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7
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Fu Z, Qiu C, Cagnone G, Tomita Y, Huang S, Cakir B, Kotoda Y, Allen W, Bull E, Akula JD, Joyal JS, Hellström A, Talukdar S, Smith LEH. Retinal glial remodeling by FGF21 preserves retinal function during photoreceptor degeneration. iScience 2021; 24:102376. [PMID: 33937726 PMCID: PMC8079476 DOI: 10.1016/j.isci.2021.102376] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/13/2021] [Accepted: 03/25/2021] [Indexed: 12/18/2022] Open
Abstract
The group of retinal degenerations, retinitis pigmentosa (RP), comprises more than 150 genetic abnormalities affecting photoreceptors. Finding degenerative pathways common to all genetic abnormalities may allow general treatment such as neuroprotection. Neuroprotection may include enhancing the function of cells that directly support photoreceptors, retinal pigment epithelial cells, and Müller glia. Treatment with fibroblast growth factor 21 (FGF21), a neuroprotectant, from postnatal week 4-10, during rod and cone loss in P23H mice (an RP model) with retinal degeneration, preserved photoreceptor function and normalized Müller glial cell morphology. Single-cell transcriptomics of retinal cells showed that FGF21 receptor Fgfr1 was specifically expressed in Müller glia/astrocytes. Of all retinal cells, FGF21 predominantly affected genes in Müller glia/astrocytes with increased expression of axon development and synapse formation pathway genes. Therefore, enhancing retinal glial axon and synapse formation with neurons may preserve retinal function in RP and may suggest a general therapeutic approach for retinal degenerative diseases.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,The Manton Center for Orphan Disease, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Chenxi Qiu
- Department of Medicine, Division of Translational Therapeutics, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Gael Cagnone
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Qc H3A 0C4, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Qc H3A 0C4, Canada
| | - Yohei Tomita
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Shuo Huang
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Bertan Cakir
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yumi Kotoda
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - William Allen
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Edward Bull
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - James D Akula
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jean-Sébastien Joyal
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Qc H3A 0C4, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Qc H3A 0C4, Canada
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg 405 30, Sweden
| | - Saswata Talukdar
- Cardiometabolic Diseases, Merck Research Laboratories, 33 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Genc AM, Makia MS, Sinha T, Conley SM, Al-Ubaidi MR, Naash MI. Elimination of a Retinal Riboflavin Binding Protein Exacerbates Degeneration in a Model of Cone-Rod Dystrophy. Invest Ophthalmol Vis Sci 2021; 61:17. [PMID: 32516403 PMCID: PMC7415289 DOI: 10.1167/iovs.61.6.17] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose Riboflavin and its cofactors are essential for cellular energy generation, responses to oxidative stress, and overall homeostasis. Retbindin is a novel retina-specific riboflavin binding protein essential for the maintenance of retinal flavin levels, but its function remains poorly understood. To further elucidate the function of retbindin in retinal health and disease, we evaluated its role in retinal degeneration in a cone-rod dystrophy model associated with the R172W mutation in the photoreceptor tetraspanin Prph2. Methods We performed structural, functional, and biochemical characterization of R172W-Prph2 mice with and without retbindin (Rtbdn-/-/Prph2R172W). Results Retbindin is significantly upregulated during degeneration in the R172W model, suggesting that retbindin plays a protective role in retinal degenerative diseases. This hypothesis was supported by our findings that R172W mice lacking retbindin (Rtbdn-/-/Prph2R172W) exhibit functional and structural defects in rods and cones that are significantly worse than in controls. Retinal flavin levels were also altered in the Rtbdn-/-/Prph2R172W retina. However, in contrast to the Rtbdn-/- retina which has reduced flavin levels compared to wild-type, Rtbdn-/-/Prph2R172W retinas exhibited elevated levels of riboflavin and the flavin cofactor FMN. Conclusions These results indicate that retbindin plays a protective role during retinal degeneration, but that its function is more complex than previously thought, and suggest a possible role for retbindin in protecting the retina from phototoxicity associated with unbound flavins. This study highlights the essential role of precisely regulated homeostatic mechanisms in photoreceptors, and shows that disruption of this metabolic balance can contribute to the degenerative process associated with other cellular defects.
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Fu Z, Sun Y, Cakir B, Tomita Y, Huang S, Wang Z, Liu CH, S. Cho S, Britton W, S. Kern T, Antonetti DA, Hellström A, E.H. Smith L. Targeting Neurovascular Interaction in Retinal Disorders. Int J Mol Sci 2020; 21:E1503. [PMID: 32098361 PMCID: PMC7073081 DOI: 10.3390/ijms21041503] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/13/2020] [Accepted: 02/21/2020] [Indexed: 02/07/2023] Open
Abstract
The tightly structured neural retina has a unique vascular network comprised of three interconnected plexuses in the inner retina (and choroid for outer retina), which provide oxygen and nutrients to neurons to maintain normal function. Clinical and experimental evidence suggests that neuronal metabolic needs control both normal retinal vascular development and pathological aberrant vascular growth. Particularly, photoreceptors, with the highest density of mitochondria in the body, regulate retinal vascular development by modulating angiogenic and inflammatory factors. Photoreceptor metabolic dysfunction, oxidative stress, and inflammation may cause adaptive but ultimately pathological retinal vascular responses, leading to blindness. Here we focus on the factors involved in neurovascular interactions, which are potential therapeutic targets to decrease energy demand and/or to increase energy production for neovascular retinal disorders.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
- Manton Center for Orphan Disease, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Ye Sun
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - Bertan Cakir
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - Yohei Tomita
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - Shuo Huang
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - Zhongxiao Wang
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - Chi-Hsiu Liu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - Steve S. Cho
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - William Britton
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
| | - Timothy S. Kern
- Center for Translational Vision Research, Gavin Herbert Eye Institute, Irvine, CA 92697, USA;
| | - David A. Antonetti
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA;
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Göteborg, Sweden;
| | - Lois E.H. Smith
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Z.F.); (Y.S.); (B.C.); (Y.T.); (S.H.); (Z.W.); (C.-H.L.); (S.S.C.); (W.B.)
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10
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Fu Z, Chen CT, Cagnone G, Heckel E, Sun Y, Cakir B, Tomita Y, Huang S, Li Q, Britton W, Cho SS, Kern TS, Hellström A, Joyal JS, Smith LE. Dyslipidemia in retinal metabolic disorders. EMBO Mol Med 2019; 11:e10473. [PMID: 31486227 PMCID: PMC6783651 DOI: 10.15252/emmm.201910473] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/10/2019] [Accepted: 08/15/2019] [Indexed: 12/24/2022] Open
Abstract
The light‐sensitive photoreceptors in the retina are extremely metabolically demanding and have the highest density of mitochondria of any cell in the body. Both physiological and pathological retinal vascular growth and regression are controlled by photoreceptor energy demands. It is critical to understand the energy demands of photoreceptors and fuel sources supplying them to understand neurovascular diseases. Retinas are very rich in lipids, which are continuously recycled as lipid‐rich photoreceptor outer segments are shed and reformed and dietary intake of lipids modulates retinal lipid composition. Lipids (as well as glucose) are fuel substrates for photoreceptor mitochondria. Dyslipidemia contributes to the development and progression of retinal dysfunction in many eye diseases. Here, we review photoreceptor energy demands with a focus on lipid metabolism in retinal neurovascular disorders.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA.,Manton Center for Orphan Disease, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Chuck T Chen
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Gael Cagnone
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Emilie Heckel
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Ye Sun
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Bertan Cakir
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Yohei Tomita
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Shuo Huang
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Qian Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - William Britton
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Steve S Cho
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Timothy S Kern
- Center for Translational Vision Research, Gavin Herbert Eye Institute, Irvine, CA, USA
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Jean-Sébastien Joyal
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Lois Eh Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
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11
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Bowl W, Lorenz B, Stieger K, Schweinfurth S, Holve K, Andrassi-Darida M. Fundus-Controlled Dark Adaptometry in Young Children Without and With Spontaneously Regressed Retinopathy of Prematurity. Transl Vis Sci Technol 2019; 8:62. [PMID: 31293816 PMCID: PMC6602151 DOI: 10.1167/tvst.8.3.62] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 03/20/2019] [Indexed: 02/01/2023] Open
Abstract
Purpose We correlate dark adaptation course with foveal morphologic alterations in preterm and term-born children using a modified fundus-controlled perimeter and spectral domain–optical coherence tomography (SD-OCT) imaging. Methods We performed fundus-controlled chromatic dark adaptometry in premature children aged 6 to 13 years without retinopathy of prematurity (no-ROP; n = 61) and with spontaneously regressed ROP (sr-ROP, n = 29), and in 11 age-matched term-born children. The degree of macular developmental arrest (MDA), defined as a disproportion of the outer nuclear layer to inner retinal layers in the fovea (ONL+/IRL-ratio), was analyzed with the DiOCTA tool in SD-OCT scans. Results Children with MDA showed a flatter dark adaptation course progression with a significant rod-mediated sensitivity recovery delay (0.0113 vs. 0.0253 dB/s; P < 0.001). Preterm-born children with regular foveal morphology reached the final rod-mediated dark-adapted threshold at 12 minutes after bleach at 18.8 dB, compared to after 18.7 minutes at 17.6 dB in children with MDA (no significant difference in final threshold; P = 0.773). The cone-mediated dark adaptation progression showed a significant lower final threshold in children with MDA (6.0 vs. 8.1 dB; P = 0.004). Conclusions Changes in dark adaptation were seen in the presence of MDA observed in premature children in the no-ROP and sr-ROP groups. MDA in former premature children is associated with functional deficits of cone and rod photoreceptor visual pathways. Translational Relevance Morphologic alterations in the central retina of premature children, evident in SD-OCT, are associated with long-term functional deficits in the rod and cone pathways, particularly evident in the rod dark adaptation course measured at 12° eccentricity. This indicates a more widespread retinal functional pathology not limited to the fovea, but occurring together with foveal alterations best defined as MDA.
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Affiliation(s)
- Wadim Bowl
- Department of Ophthalmology, Justus-Liebig-University, Giessen, Germany
| | - Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig-University, Giessen, Germany
| | - Knut Stieger
- Department of Ophthalmology, Justus-Liebig-University, Giessen, Germany
| | | | - Kerstin Holve
- Department of Ophthalmology, Justus-Liebig-University, Giessen, Germany
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12
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Xu W, Wu Y, Hu Z, Sun L, Dou G, Zhang Z, Wang H, Guo C, Wang Y. Exosomes from Microglia Attenuate Photoreceptor Injury and Neovascularization in an Animal Model of Retinopathy of Prematurity. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 16:778-790. [PMID: 31163320 PMCID: PMC6545376 DOI: 10.1016/j.omtn.2019.04.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 12/11/2022]
Abstract
The role of microglia in the pathophysiology of ischemic retinal diseases has been studied extensively. Exosomes from microglial cells exert protective effects during several nervous system diseases, but their roles in hypoxia-induced retinopathy remain unclear. In our study, exosomes derived from microglial cells were injected into the vitreous body of mice with oxygen-induced retinopathy (OIR). Results showed that exosome-treated OIR mice exhibited smaller avascular areas and fewer neovascular tufts in addition to decreased vascular endothelial growth factor (VEGF) and transforming growth factor β (TGF-β) expression. Moreover, photoreceptor apoptosis was suppressed by exosome injection. Mechanistically, exosomes from microglial cells were incorporated into photoreceptors in vitro and inhibited the inositol-requiring enzyme 1α (IRE1α)-X-box binding protein 1 (XBP1) cascade, which contributes to hypoxia-induced photoreceptor apoptosis. Furthermore, the exosomes also downregulated the mRNA and protein levels of VEGF and TGF-β in hypoxia-exposed photoreceptors. A microRNA assay showed that microRNA-24-3p (miR-24-3p) levels were extremely high in exosomes from microglial cells, suggesting that this could be the key molecule that inhibits the hypoxia-induced expression of IRE1α in photoreceptors. These findings delineate a novel exosome-mediated mechanism of microglial cell-photoreceptor crosstalk that facilitates normal angiogenesis and visual function in OIR mice; thus, our results also suggest a potential therapeutic approach for retinopathy of prematurity.
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Affiliation(s)
- Wenqin Xu
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Ying Wu
- Department of Thyroid, Breast and Vascular Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zhicha Hu
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Lijuan Sun
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Guorui Dou
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zifeng Zhang
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Haiyang Wang
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Changmei Guo
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yusheng Wang
- Department of Ophthalmology, Eye Institute of China PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
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13
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Fu Z, Löfqvist CA, Liegl R, Wang Z, Sun Y, Gong Y, Liu CH, Meng SS, Burnim SB, Arellano I, Chouinard MT, Duran R, Poblete A, Cho SS, Akula JD, Kinter M, Ley D, Pupp IH, Talukdar S, Hellström A, Smith LE. Photoreceptor glucose metabolism determines normal retinal vascular growth. EMBO Mol Med 2019; 10:76-90. [PMID: 29180355 PMCID: PMC5760850 DOI: 10.15252/emmm.201707966] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The neural cells and factors determining normal vascular growth are not well defined even though vision‐threatening neovessel growth, a major cause of blindness in retinopathy of prematurity (ROP) (and diabetic retinopathy), is driven by delayed normal vascular growth. We here examined whether hyperglycemia and low adiponectin (APN) levels delayed normal retinal vascularization, driven primarily by dysregulated photoreceptor metabolism. In premature infants, low APN levels correlated with hyperglycemia and delayed retinal vascular formation. Experimentally in a neonatal mouse model of postnatal hyperglycemia modeling early ROP, hyperglycemia caused photoreceptor dysfunction and delayed neurovascular maturation associated with changes in the APN pathway; recombinant mouse APN or APN receptor agonist AdipoRon treatment normalized vascular growth. APN deficiency decreased retinal mitochondrial metabolic enzyme levels particularly in photoreceptors, suppressed retinal vascular development, and decreased photoreceptor platelet‐derived growth factor (Pdgfb). APN pathway activation reversed these effects. Blockade of mitochondrial respiration abolished AdipoRon‐induced Pdgfb increase in photoreceptors. Photoreceptor knockdown of Pdgfb delayed retinal vascular formation. Stimulation of the APN pathway might prevent hyperglycemia‐associated retinal abnormalities and suppress phase I ROP in premature infants.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Chatarina A Löfqvist
- Section for Ophthalmology, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Raffael Liegl
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Zhongxiao Wang
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ye Sun
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Yan Gong
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Chi-Hsiu Liu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Steven S Meng
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Samuel B Burnim
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ivana Arellano
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Rubi Duran
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexander Poblete
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Steve S Cho
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - James D Akula
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael Kinter
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - David Ley
- Pediatrics, Department of Clinical Sciences, Skåne University Hospital and University of Lund, Lund, Sweden
| | - Ingrid Hansen Pupp
- Pediatrics, Department of Clinical Sciences, Skåne University Hospital and University of Lund, Lund, Sweden
| | | | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Lois Eh Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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14
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Hansen RM, Moskowitz A, Akula JD, Fulton AB. The neural retina in retinopathy of prematurity. Prog Retin Eye Res 2017; 56:32-57. [PMID: 27671171 PMCID: PMC5237602 DOI: 10.1016/j.preteyeres.2016.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/15/2016] [Accepted: 09/20/2016] [Indexed: 12/26/2022]
Abstract
Retinopathy of prematurity (ROP) is a neurovascular disease that affects prematurely born infants and is known to have significant long term effects on vision. We conducted the studies described herein not only to learn more about vision but also about the pathogenesis of ROP. The coincidence of ROP onset and rapid developmental elongation of the rod photoreceptor outer segments motivated us to consider the role of the rods in this disease. We used noninvasive electroretinographic (ERG), psychophysical, and retinal imaging procedures to study the function and structure of the neurosensory retina. Rod photoreceptor and post-receptor responses are significantly altered years after the preterm days during which ROP is an active disease. The alterations include persistent rod dysfunction, and evidence of compensatory remodeling of the post-receptor retina is found in ERG responses to full-field stimuli and in psychophysical thresholds that probe small retinal regions. In the central retina, both Mild and Severe ROP delay maturation of parafoveal scotopic thresholds and are associated with attenuation of cone mediated multifocal ERG responses, significant thickening of post-receptor retinal laminae, and dysmorphic cone photoreceptors. These results have implications for vision and control of eye growth and refractive development and suggest future research directions. These results also lead to a proposal for noninvasive management using light that may add to the currently invasive therapeutic armamentarium against ROP.
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Affiliation(s)
- Ronald M Hansen
- Department of Ophthalmology, Children's Hospital and Harvard Medical School, 300 Longwood Ave., Boston, MA 02115-5737, USA.
| | - Anne Moskowitz
- Department of Ophthalmology, Children's Hospital and Harvard Medical School, 300 Longwood Ave., Boston, MA 02115-5737, USA.
| | - James D Akula
- Department of Ophthalmology, Children's Hospital and Harvard Medical School, 300 Longwood Ave., Boston, MA 02115-5737, USA.
| | - Anne B Fulton
- Department of Ophthalmology, Children's Hospital and Harvard Medical School, 300 Longwood Ave., Boston, MA 02115-5737, USA.
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15
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Moskowitz A, Hansen RM, Fulton AB. Retinal, visual, and refractive development in retinopathy of prematurity. Eye Brain 2016; 8:103-111. [PMID: 28539805 PMCID: PMC5398748 DOI: 10.2147/eb.s95021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The pivotal role of the neurosensory retina in retinopathy of prematurity (ROP) disease processes has been amply demonstrated in rat models. We have hypothesized that analogous cellular processes are operative in human ROP and have evaluated these presumptions in a series on non-invasive investigations of the photoreceptor and post-receptor peripheral and central retina in infants and children. Key results are slowed kinetics of phototransduction and deficits in photoreceptor sensitivity that persist years after ROP has completely resolved based on clinical criteria. On the other hand, deficits in post-receptor sensitivity are present in infancy regardless of the severity of the ROP but are not present in older children if the ROP was so mild that it never required treatment and resolved without a clinical trace. Accompanying the persistent deficits in photoreceptor sensitivity, there is increased receptive field size and thickening of the post-receptor retinal laminae in the peripheral retina of ROP subjects. In the late maturing central retina, which mediates visual acuity, attenuation of multifocal electroretinogram activity in the post-receptor retina led us to the discovery of a shallow foveal pit and significant thickening of the post-receptor retinal laminae in the macular region; this is most likely due to failure of the normal centrifugal movement of the post-receptor cells during foveal development. As for refractive development, myopia, at times high, is more common in ROP subjects than in control subjects, in accord with refractive findings in other populations of former preterms. This information about the neurosensory retina enhances understanding of vision in patients with a history of ROP, and taken as a whole, raises the possibility that the neurosensory retina is a target for therapeutic intervention.
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Affiliation(s)
- Anne Moskowitz
- Department of Ophthalmology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Ronald M Hansen
- Department of Ophthalmology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Anne B Fulton
- Department of Ophthalmology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
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16
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Akula JD, Noonan ER, Di Nardo A, Favazza TL, Zhang N, Sahin M, Hansen RM, Fulton AB. Vigabatrin can enhance electroretinographic responses in pigmented and albino rats. Doc Ophthalmol 2015; 131:1-11. [PMID: 25761928 DOI: 10.1007/s10633-015-9491-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/23/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the effects of the antiepileptic medication vigabatrin (VGB) on the retina of pigmented rats. METHODS Scotopic and photopic electroretinograms were recorded from dark- and light-adapted Long-Evans (pigmented) and Sprague Dawley (albino) rats administered, daily, 52-55 injections of 250 mg·kg(-1)·day(-1) VGB or 25-26 injections of 500 mg·kg(-1)·day(-1) VGB, or a corresponding number of sham injections. Sensitivity and saturated amplitude of the rod photoresponse (S, Rm(P3)) and postreceptor response (1/σ, Vm) were derived, as were sensitivity and amplitude of the cone-mediated postreceptor response (1/σ(cone), Vm(cone)). The oscillatory potentials and responses to a series of flickering lights (6.25, 12.5, 25 and 50 Hz) were studied in the time and frequency domains. A subset of rats' eyes was harvested for Western blotting or histology. RESULTS Of the parameters derived from dark-adapted ERG responses, in both pigmented and albino rats, VGB repeatedly and reliably enhanced electroretinographic parameters; no significant ERG deficits were noted. No significant alterations were observed in ER/oxidative stress or in the Akt cell death/survival pathway. There were migrations of photoreceptor nuclei toward the RPE and outgrowths of bipolar cell dendrites into the outer nuclear layer in VGB-treated rats; these were never observed in sham-treated animals. CONCLUSIONS Although VGB is associated with retinal dysfunction in patients and VGB toxicity has been demonstrated by other laboratories in the albino rat, in our pigmented and albino rats, VGB did not induce deficits in, but rather enhanced, retinal function. Nonetheless, retinal neuronal dysplasia was observed.
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17
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Querques G, Rosenfeld PJ, Cavallero E, Borrelli E, Corvi F, Querques L, Bandello FM, Zarbin MA. Treatment of Dry Age-Related Macular Degeneration. Ophthalmic Res 2014; 52:107-15. [DOI: 10.1159/000363187] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 04/12/2014] [Indexed: 11/19/2022]
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18
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Kang-Mieler JJ, Osswald CR, Mieler WF. Advances in ocular drug delivery: emphasis on the posterior segment. Expert Opin Drug Deliv 2014; 11:1647-60. [PMID: 24975820 DOI: 10.1517/17425247.2014.935338] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Recent advances in pharmacological therapies to treat ocular diseases such as glaucoma, age-related macular degeneration, diabetic macular edema and retinal vascular occlusions have greatly improved the prognosis for these diseases. Due to these advances in pharmacological therapy, there is a great deal of interest in minimally invasive delivery methods, which has generated rapid developments in the field of ocular drug delivery. AREAS COVERED This review will summarize currently available and recent developments for ocular drug delivery to both the anterior and posterior segments. Modes of delivery, including topical, systemic, transcleral/periocular and intravitreal, will be discussed and corresponding examples will be given. This review will highlight the advantages and disadvantages of each mode of delivery and discuss strategies to address these issues. EXPERT OPINION An ideal therapy should maintain effective levels of drug for the intended duration of treatment following a single application, yet a significant number of months of therapy may be required. There are numerous approaches under investigation to improve treatment options. From the use of novel biomaterial implants and depots for sustained release, to prodrug formations, to iontophoresis to improve drug delivery, the main emphasis will continue to be placed on less invasive, longer acting, sustained release formulations in the treatment of numerous ocular disorders.
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Affiliation(s)
- Jennifer J Kang-Mieler
- Illinois Institute of Technology, Department of Biomedical Engineering , Chicago, IL 60616 , USA
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19
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Narayanan SP, Xu Z, Putluri N, Sreekumar A, Lemtalsi T, Caldwell RW, Caldwell RB. Arginase 2 deficiency reduces hyperoxia-mediated retinal neurodegeneration through the regulation of polyamine metabolism. Cell Death Dis 2014; 5:e1075. [PMID: 24556690 PMCID: PMC3944241 DOI: 10.1038/cddis.2014.23] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 12/27/2013] [Accepted: 01/07/2014] [Indexed: 11/16/2022]
Abstract
Hyperoxia treatment has been known to induce neuronal and glial death in the developing central nervous system. Retinopathy of prematurity (ROP) is a devastating disease in premature infants and a major cause of childhood vision impairment. Studies indicate that, in addition to vascular injury, retinal neurons are also affected in ROP. Using an oxygen-induced retinopathy (OIR) mouse model for ROP, we have previously shown that deletion of the arginase 2 (A2) significantly reduced neuro-glial injury and improved retinal function. In the current study, we investigated the mechanism of A2 deficiency-mediated neuroprotection in the OIR retina. Hyperoxia treatment has been known to induce neuronal death in neonates. During the hyperoxia phase of OIR, a significant increase in the number of apoptotic cells was observed in the wild-type (WT) OIR retina compared with A2-deficient OIR. Mass spectrometric analysis showed alterations in polyamine metabolism in WT OIR retina. Further, increased expression level of spermine oxidase was observed in WT OIR retina, suggesting increased oxidation of polyamines in OIR retina. These changes were minimal in A2-deficient OIR retina. Treatment using the polyamine oxidase inhibitor, N, N'-bis (2, 3-butadienyl)-1, 4-butanediamine dihydrochloride, significantly improved neuronal survival during OIR treatment. Our data suggest that retinal arginase is involved in the hyperoxia-induced neuronal degeneration in the OIR model, through the regulation of polyamine metabolism.
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Affiliation(s)
- S P Narayanan
- Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA
- Vascular Biology Center, Georgia Regents University, Augusta, GA, USA
- Department of Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA, USA
| | - Z Xu
- Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA
- Vascular Biology Center, Georgia Regents University, Augusta, GA, USA
| | - N Putluri
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - A Sreekumar
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - T Lemtalsi
- Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA
- Vascular Biology Center, Georgia Regents University, Augusta, GA, USA
| | - R W Caldwell
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA, USA
| | - R B Caldwell
- Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA
- Vascular Biology Center, Georgia Regents University, Augusta, GA, USA
- Department of Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA, USA
- Charlie Norwood VA Medical Center, Augusta, GA, USA
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20
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Zhang N, Favazza TL, Baglieri AM, Benador IY, Noonan ER, Fulton AB, Hansen RM, Iuvone PM, Akula JD. The rat with oxygen-induced retinopathy is myopic with low retinal dopamine. Invest Ophthalmol Vis Sci 2013; 54:8275-84. [PMID: 24168993 DOI: 10.1167/iovs.13-12544] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
PURPOSE Dopamine (DA) is a neurotransmitter implicated both in modulating neural retinal signals and in eye growth. Therefore, it may participate in the pathogenesis of the most common clinical sequelae of retinopathy of prematurity (ROP), visual dysfunction and myopia. Paradoxically, in ROP myopia the eye is usually small. The eye of the rat with oxygen-induced retinopathy (OIR) is characterized by retinal dysfunction and short axial length. There have been several investigations of the early maturation of DA in rat retina, but little at older ages, and not in the OIR rat. Therefore, DA, retinal function, and refractive state were investigated in the OIR rat. METHODS In one set of rats, the development of dopaminergic (DAergic) networks was evaluated in retinal cross-sections from rats aged 14 to 120 days using antibodies against tyrosine hydroxylase (TH, the rate-limiting enzyme in the biosynthesis of DA). In another set of rats, retinoscopy was used to evaluate spherical equivalent (SE), electoretinography (ERG) was used to evaluate retinal function, and high-pressure liquid chromatography (HPLC) was used to evaluate retinal contents of DA, its precursor levodopamine (DOPA), and its primary metabolite 3,4-dihydroxyphenylacetic acid (DOPAC). RESULTS The normally rapid postnatal ramification of DAergic neurons was disrupted in OIR rats. Retinoscopy revealed that OIR rats were relatively myopic. In the same eyes, ERG confirmed retinal dysfunction in OIR. HPLC of those eyes' retinae confirmed low DA. Regression analysis indicated that DA metabolism (evaluated by the ratio of DOPAC to DA) was an important additional predictor of myopia beyond OIR. CONCLUSIONS The OIR rat is the first known animal model of myopia in which the eye is smaller than normal. Dopamine may modulate, or fail to modulate, neural activity in the OIR eye, and thus contribute to this peculiar myopia.
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Affiliation(s)
- Nan Zhang
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts
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21
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Narayanan SP, Rojas M, Suwanpradid J, Toque HA, Caldwell RW, Caldwell RB. Arginase in retinopathy. Prog Retin Eye Res 2013; 36:260-80. [PMID: 23830845 PMCID: PMC3759622 DOI: 10.1016/j.preteyeres.2013.06.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/14/2013] [Accepted: 06/25/2013] [Indexed: 12/12/2022]
Abstract
Ischemic retinopathies, such as diabetic retinopathy (DR), retinopathy of prematurity and retinal vein occlusion are a major cause of blindness in developed nations worldwide. Each of these conditions is associated with early neurovascular dysfunction. However, conventional therapies target clinically significant macula edema or neovascularization, which occur much later. Intra-ocular injections of anti-VEGF show promise in reducing retinal edema, but the effects are usually transient and the need for repeated injections increases the risk of intraocular infection. Laser photocoagulation can control pathological neovascularization, but may impair vision and in some patients the retinopathy continues to progress. Moreover, neither treatment targets early stage disease or promotes repair. This review examines the potential role of the ureahydrolase enzyme arginase as a therapeutic target for the treatment of ischemic retinopathy. Arginase metabolizes l-arginine to form proline, polyamines and glutamate. Excessive arginase activity reduces the l-arginine supply for nitric oxide synthase (NOS), causing it to become uncoupled and produce superoxide and less NO. Superoxide and NO react and form the toxic oxidant peroxynitrite. The catabolic products of polyamine oxidation and glutamate can induce more oxidative stress and DNA damage, both of which can cause cellular injury. Studies indicate that neurovascular injury during retinopathy is associated with increased arginase expression/activity, decreased NO, polyamine oxidation, formation of superoxide and peroxynitrite and dysfunction and injury of both vascular and neural cells. Furthermore, data indicate that the cytosolic isoform arginase I (AI) is involved in hyperglycemia-induced dysfunction and injury of vascular endothelial cells whereas the mitochondrial isoform arginase II (AII) is involved in neurovascular dysfunction and death following hyperoxia exposure. Thus, we postulate that activation of the arginase pathway causes neurovascular injury by uncoupling NOS and inducing polyamine oxidation and glutamate formation, thereby reducing NO and increasing oxidative stress, all of which contribute to the retinopathic process.
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Affiliation(s)
- S. Priya Narayanan
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Modesto Rojas
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Jutamas Suwanpradid
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Haroldo A. Toque
- Department of Pharmacology & Toxicology, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - R. William Caldwell
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Department of Pharmacology & Toxicology, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Ruth B. Caldwell
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- VA Medical Center, One Freedom Way, Augusta, GA, USA
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Next-generation sequencing analysis of gene regulation in the rat model of retinopathy of prematurity. Doc Ophthalmol 2013; 127:13-31. [PMID: 23775346 DOI: 10.1007/s10633-013-9396-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 06/03/2013] [Indexed: 01/01/2023]
Abstract
PURPOSE The purpose of this study was to identify the genes, biochemical signaling pathways, and biological themes involved in the pathogenesis of retinopathy of prematurity (ROP). METHODS Next-generation sequencing (NGS) was performed on the RNA transcriptome of rats with the Penn et al. (Pediatr Res 36:724-731, 1994) oxygen-induced retinopathy model of ROP at the height of vascular abnormality, postnatal day (P) 19, and normalized to age-matched, room-air-reared littermate controls. Eight custom-developed pathways with potential relevance to known ROP sequelae were evaluated for significant regulation in ROP: The three major Wnt signaling pathways, canonical, planar cell polarity (PCP), and Wnt/Ca(2+); two signaling pathways mediated by the Rho GTPases RhoA and Cdc42, which are, respectively, thought to intersect with canonical and non-canonical Wnt signaling; nitric oxide signaling pathways mediated by two nitric oxide synthase (NOS) enzymes, neuronal (nNOS) and endothelial (eNOS); and the retinoic acid (RA) signaling pathway. Regulation of other biological pathways and themes was detected by gene ontology using the Kyoto Encyclopedia of Genes and Genomes and the NIH's Database for Annotation, Visualization, and Integrated Discovery's GO terms databases. RESULTS Canonical Wnt signaling was found to be regulated, but the non-canonical PCP and Wnt/Ca(2+) pathways were not. Nitric oxide signaling, as measured by the activation of nNOS and eNOS, was also regulated, as was RA signaling. Biological themes related to protein translation (ribosomes), neural signaling, inflammation and immunity, cell cycle, and cell death were (among others) highly regulated in ROP rats. CONCLUSIONS These several genes and pathways identified by NGS might provide novel targets for intervention in ROP.
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Alterations of the tunica vasculosa lentis in the rat model of retinopathy of prematurity. Doc Ophthalmol 2013; 127:3-11. [PMID: 23748796 DOI: 10.1007/s10633-013-9392-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/22/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE To study the relationship between retinal and tunica vasculosa lentis (TVL) disease in retinopathy of prematurity (ROP). Although the clinical hallmark of ROP is abnormal retinal blood vessels, the vessels of the anterior segment, including the TVL, are also altered. METHODS ROP was induced in Long-Evans pigmented and Sprague Dawley albino rats; room-air-reared (RAR) rats served as controls. Then, fluorescein angiographic images of the TVL and retinal vessels were serially obtained with a scanning laser ophthalmoscope near the height of retinal vascular disease, ~20 days of age, and again at 30 and 64 days of age. Additionally, electroretinograms (ERGs) were obtained prior to the first imaging session. The TVL images were analyzed for percent coverage of the posterior lens. The tortuosity of the retinal arterioles was determined using Retinal Image multiScale Analysis (Gelman et al. in Invest Ophthalmol Vis Sci 46:4734-4738, 2005). RESULTS In the youngest ROP rats, the TVL was dense, while in RAR rats, it was relatively sparse. By 30 days, the TVL in RAR rats had almost fully regressed, while in ROP rats, it was still pronounced. By the final test age, the TVL had completely regressed in both ROP and RAR rats. In parallel, the tortuous retinal arterioles in ROP rats resolved with increasing age. ERG components indicating postreceptoral dysfunction, the b-wave, and oscillatory potentials were attenuated in ROP rats. CONCLUSIONS These findings underscore the retinal vascular abnormalities and, for the first time, show abnormal anterior segment vasculature in the rat model of ROP. There is delayed regression of the TVL in the rat model of ROP. This demonstrates that ROP is a disease of the whole eye.
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Blom JJ, Giove TJ, Favazza TL, Akula JD, Eldred WD. Inhibition of the adrenomedullin/nitric oxide signaling pathway in early diabetic retinopathy. J Ocul Biol Dis Infor 2012; 4:70-82. [PMID: 23316263 DOI: 10.1007/s12177-011-9072-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/05/2011] [Indexed: 12/18/2022] Open
Abstract
The nitric oxide (NO) signaling pathway is integrally involved in visual processing and changes in the NO pathway are measurable in eyes of diabetic patients. The small peptide adrenomedullin (ADM) can activate a signaling pathway to increase the enzyme activity of neuronal nitric oxide synthase (nNOS). ADM levels are elevated in eyes of diabetic patients and therefore, ADM may play a role in the pathology of diabetic retinopathy. The goal of this research was to test the effects of inhibiting the ADM/NO signaling pathway in early diabetic retinopathy. Inhibition of this pathway decreased NO production in high-glucose retinal cultures. Treating diabetic mice with the PKC β inhibitor ruboxistaurin for 5 weeks lowered ADM mRNA levels and ADM-like immunoreactivity and preserved retinal function as assessed by electroretinography. The results of this study indicate that inhibiting the ADM/NO signaling pathway prevents neuronal pathology and functional losses in early diabetic retinopathy.
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Affiliation(s)
- Jan J Blom
- Department of Biology, Boston University, Boston, MA USA
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Narayanan SP, Suwanpradid J, Saul A, Xu Z, Still A, Caldwell RW, Caldwell RB. Arginase 2 deletion reduces neuro-glial injury and improves retinal function in a model of retinopathy of prematurity. PLoS One 2011; 6:e22460. [PMID: 21811615 PMCID: PMC3141070 DOI: 10.1371/journal.pone.0022460] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 06/26/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Retinopathy of prematurity (ROP) is a major cause of vision impairment in low birth weight infants. While previous work has focused on defining the mechanisms of vascular injury leading to retinal neovascularization, recent studies show that neurons are also affected. This study was undertaken to determine the role of the mitochondrial arginine/ornithine regulating enzyme arginase 2 (A2) in retinal neuro-glial cell injury in the mouse model of ROP. METHODS AND FINDINGS Studies were performed using wild type (WT) and A2 knockout (A2-/-) mice exposed to Oxygen Induced Retinopathy (OIR). Neuronal injury and apoptosis were assessed using immunohistochemistry, TUNEL (terminal deoxynucleotidyl transferase dUTP nick end) labeling and Western blotting. Electroretinography (ERG) was used to assess retinal function. Neuro-glial injury in WT ROP mice was evident by TUNEL labeling, retinal thinning, decreases in number of rod bipolar cells and glial cell activation as compared with room air controls. Significant reduction in numbers of TUNEL positive cells, inhibition of retinal thinning, preservation of the rod bipolar cells and prevention of glial activation were observed in the A2-/- retinas. Retinal function was markedly impaired in the WT OIR mice as shown by decreases in amplitude of the b-wave of the ERG. This defect was significantly reduced in A2-/- mice. Levels of the pro-apoptotic proteins p53, cleaved caspase 9, cytochrome C and the mitochondrial protein Bim were markedly increased in WT OIR retinas compared to controls, whereas the pro-survival Mitochondrial protein BCL-xl was reduced. These alterations were largely blocked in the A2-/- OIR retina. CONCLUSIONS Our data implicate A2 in neurodegeneration during ROP. Deletion of A2 significantly improves neuronal survival and function, possibly through the regulation of mitochondrial membrane permeability mediated apoptosis during retinal ischemia. These molecular events are associated with decreased activation of glial cells, suggesting a rescue effect on macroglia as well.
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Affiliation(s)
- Subhadra P. Narayanan
- Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Department of Cellular Biology and Anatomy, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Jutamas Suwanpradid
- Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Alan Saul
- Department of Ophthalmology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Zhimin Xu
- Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Amber Still
- Department of Ophthalmology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Robert W. Caldwell
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Ruth B. Caldwell
- Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Department of Cellular Biology and Anatomy, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Department of Ophthalmology, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Charlie Norwood VA Medical Center, Augusta, Georgia, United States of America
- * E-mail:
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Bibliography. Neonatology and perinatology. Current world literature. Curr Opin Pediatr 2011; 23:253-7. [PMID: 21412083 DOI: 10.1097/mop.0b013e3283454167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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