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Wesson T, Zhang L, Morrison RA, Brookes S, Calcagno H, Finnegan P, Voytik-Harbin S, Halum S. Tissue-Engineered Implant for Hemilaryngectomy Reconstruction with Recurrent Laryngeal Nerve Injury. Laryngoscope 2024. [PMID: 38989732 DOI: 10.1002/lary.31616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/04/2024] [Accepted: 06/14/2024] [Indexed: 07/12/2024]
Abstract
OBJECTIVE Laryngeal cancer resections often require excision of portions of the larynx along with sacrifice of the ipsilateral recurrent laryngeal nerve (RLN). In such cases, there are no reconstructive options that reliably restore laryngeal function, rendering patients with severe functional impairment. To address this unmet clinical need, we extend our evaluation of a 3-implant mucosal, muscle, cartilage reconstruction approach aimed at promoting functional laryngeal restoration in a porcine hemilaryngectomy model with ipsilateral RLN transection. METHODS Six Yucatan mini-pigs underwent full-thickness hemilaryngectomies with RLN transection followed by transmural reconstruction using fabricated collagen polymeric mucosal, muscle, and cartilage replacements. To determine the effect of adding therapeutic cell populations, subsets of animals received collagen muscle implants containing motor-endplate-expressing muscle progenitor cells (MEEs) and/or collagen cartilage implants containing adipose stem cell (ASC)-derived chondrocyte-like cells. Acoustic vocalization and laryngeal electromyography (L-EMG) provided functional assessments and histopathological analysis with immunostaining was used to characterize the tissue response. RESULTS Five of six animals survived the 4-week postoperative period with weight gain, airway maintenance, and audible phonation. No tracheostomy or feeding tube was required. Gross and histological assessments of all animals revealed implant integration and regenerative remodeling of airway mucosa epithelium, muscle, and cartilage in the absence of a material-mediated foreign body reaction or biodegradation. Early voice and L-EMG data were suggestive of positive functional outcomes. CONCLUSION Laryngeal reconstruction with collagen polymeric mucosa, muscle, and cartilage replacements may provide effective restoration of function after hemilaryngectomy with RLN transection. Future preclinical studies should focus on long-term functional outcomes. LEVEL OF EVIDENCE NA Laryngoscope, 2024.
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Affiliation(s)
- Troy Wesson
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana, U.S.A
| | - Lujuan Zhang
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana, U.S.A
| | - Rachel A Morrison
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, U.S.A
| | - Sarah Brookes
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, U.S.A
| | - Haley Calcagno
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana, U.S.A
| | - Patrick Finnegan
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana, U.S.A
| | - Sherry Voytik-Harbin
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, U.S.A
| | - Stacey Halum
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana, U.S.A
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana, U.S.A
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Zhang W, Kaser-Eichberger A, Fan W, Platzl C, Schrödl F, Heindl LM. The structure and function of the human choroid. Ann Anat 2024; 254:152239. [PMID: 38432349 DOI: 10.1016/j.aanat.2024.152239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/05/2024]
Abstract
In this manuscript, the structure of the human choroid is reviewed with emphasis of the macro- and microscopic anatomy including Bruch's membrane, choriocapillaris, Sattler's and Haller's layer, and the suprachoroid. We here discuss the development of the choroid, as well as the question of choroidal lymphatics, and further the neuronal control of this tissue, as well as the pathologic angiogenesis. Wherever possible, functional aspects of the various structures are included and reviewed.
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Affiliation(s)
- Weina Zhang
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Alexandra Kaser-Eichberger
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology -Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Wanlin Fan
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Christian Platzl
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology -Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Falk Schrödl
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology -Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Ludwig M Heindl
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
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3
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Mullin NK, Voigt AP, Flamme-Wiese MJ, Liu X, Riker MJ, Varzavand K, Stone EM, Tucker BA, Mullins RF. Multimodal single-cell analysis of nonrandom heteroplasmy distribution in human retinal mitochondrial disease. JCI Insight 2023; 8:e165937. [PMID: 37289546 PMCID: PMC10443808 DOI: 10.1172/jci.insight.165937] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 06/02/2023] [Indexed: 06/10/2023] Open
Abstract
Variants within the high copy number mitochondrial genome (mtDNA) can disrupt organelle function and lead to severe multisystem disease. The wide range of manifestations observed in patients with mitochondrial disease results from varying fractions of abnormal mtDNA molecules in different cells and tissues, a phenomenon termed heteroplasmy. However, the landscape of heteroplasmy across cell types within tissues and its influence on phenotype expression in affected patients remains largely unexplored. Here, we identify nonrandom distribution of a pathogenic mtDNA variant across a complex tissue using single-cell RNA-Seq, mitochondrial single-cell ATAC sequencing, and multimodal single-cell sequencing. We profiled the transcriptome, chromatin accessibility state, and heteroplasmy in cells from the eyes of a patient with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and from healthy control donors. Utilizing the retina as a model for complex multilineage tissues, we found that the proportion of the pathogenic m.3243A>G allele was neither evenly nor randomly distributed across diverse cell types. All neuroectoderm-derived neural cells exhibited a high percentage of the mutant variant. However, a subset of mesoderm-derived lineage, namely the vasculature of the choroid, was near homoplasmic for the WT allele. Gene expression and chromatin accessibility profiles of cell types with high and low proportions of m.3243A>G implicate mTOR signaling in the cellular response to heteroplasmy. We further found by multimodal single-cell sequencing of retinal pigment epithelial cells that a high proportion of the pathogenic mtDNA variant was associated with transcriptionally and morphologically abnormal cells. Together, these findings show the nonrandom nature of mitochondrial variant partitioning in human mitochondrial disease and underscore its implications for mitochondrial disease pathogenesis and treatment.
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Affiliation(s)
- Nathaniel K. Mullin
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
- Medical Scientist Training Program, University of Iowa, Iowa City, Iowa, USA
| | - Andrew P. Voigt
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
- Medical Scientist Training Program, University of Iowa, Iowa City, Iowa, USA
| | - Miles J. Flamme-Wiese
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
| | - Xiuying Liu
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
| | - Megan J. Riker
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
| | - Katayoun Varzavand
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
| | - Edwin M. Stone
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
| | - Budd A. Tucker
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
| | - Robert F. Mullins
- University of Iowa Institute for Vision Research, Iowa City, Iowa, USA
- Department of Ophthalmology and Visual Sciences and
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Quantitative analysis of choroidal vasculature in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography angiography. Sci Rep 2022; 12:18427. [PMID: 36319689 PMCID: PMC9626581 DOI: 10.1038/s41598-022-23389-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 10/31/2022] [Indexed: 11/17/2022] Open
Abstract
We aimed to quantitatively compare the choroid blood flow and choroid thickness at the periphery among eyes with central serous chorioretinopathy (CSC), fellow eyes and healthy eyes using ultra-widefield swept-source optical coherence tomography angiography (UWF SS-OCTA). Retrospective analysis of 49 patients with CSC (98 eyes, including unaffected fellow eyes) and 49 age and sex matched controls were included. We obtained 3-dimensional data of vertical 20 mm × horizontal 24 mm × scan depth 6 mm, comprising 9 subfields (superotemporal, upper, superonasal, temporal, central, nasal, inferotemporal, lower, inferonasal regions). CSC eyes presented with greater density of large-vessel choroidal layer in all the 9 subfields compared with controls. Compared with normal eyes, CSC eyes had greater choroidal thickness (superotemporal, upper, superonasal, temporal, central, nasal, inferotemporal, and inferonasal subfields) and choroidal volume (superotemporal, upper, superonasal, temporal, central, and nasal subfields). Compared with control eyes, the choriocapillaris density in the superotemporal, inferotemporal and inferonasal subfields was greater in patients with CSC. Our study may provide further evidence for the congestion of vortex vein in the pathogenesis of CSC. UWF SS-OCTA can be used to evaluate the abnormalities of the choroidal structures even at the periphery in eyes with CSC.
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Liu P, Lavine JA, Fawzi A, Quaggin SE, Thomson BR. Angiopoietin-1 Is Required for Vortex Vein and Choriocapillaris Development in Mice. Arterioscler Thromb Vasc Biol 2022; 42:1413-1427. [PMID: 36172864 PMCID: PMC9613622 DOI: 10.1161/atvbaha.122.318151] [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: 03/22/2022] [Accepted: 09/16/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND The choroidal vasculature, including the choriocapillaris and vortex veins, is essential for providing nutrients to the metabolically demanding photoreceptors and retinal pigment epithelium. Choroidal vascular dysfunction leads to vision loss and is associated with age-related macular degeneration and the poorly understood pachychoroid diseases including central serous chorioretinopathy and polypoidal choroidal vasculopathy that are characterized by formation of dilated pachyvessels throughout the choroid. METHODS Using neural crest-specific Angpt1 knockout mice, we show that Angiopoietin 1, a ligand of the endothelial receptor TEK (also known as Tie2) is essential for choriocapillaris development and vortex vein patterning. RESULTS Lacking choroidal ANGPT1, neural crest-specific Angpt1 knockout eyes exhibited marked choriocapillaris attenuation and 50% reduction in number of vortex veins, with only 2 vortex veins present in the majority of eyes. Shortly after birth, dilated choroidal vessels resembling human pachyvessels were observed extending from the remaining vortex veins and displacing the choriocapillaris, leading to retinal pigment epithelium dysfunction and subretinal neovascularization similar to that seen in pachychoroid disease. CONCLUSIONS Together, these findings identify a new role for ANGPT1 in ocular vascular development and demonstrate a clear link between vortex vein dysfunction, pachyvessel formation, and disease.
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Affiliation(s)
- Pan Liu
- Section of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago IL, USA
- Feinberg Cardiovascular and Renal Research Inst. Chicago, IL, USA
| | - Jeremy A. Lavine
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Amani Fawzi
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Susan E Quaggin
- Section of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago IL, USA
- Feinberg Cardiovascular and Renal Research Inst. Chicago, IL, USA
| | - Benjamin R. Thomson
- Feinberg Cardiovascular and Renal Research Inst. Chicago, IL, USA
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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6
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Enyong EN, Gurley JM, De Ieso ML, Stamer WD, Elliott MH. Caveolar and non-Caveolar Caveolin-1 in ocular homeostasis and disease. Prog Retin Eye Res 2022; 91:101094. [PMID: 35729002 PMCID: PMC9669151 DOI: 10.1016/j.preteyeres.2022.101094] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/03/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022]
Abstract
Caveolae, specialized plasma membrane invaginations present in most cell types, play important roles in multiple cellular processes including cell signaling, lipid uptake and metabolism, endocytosis and mechanotransduction. They are found in almost all cell types but most abundant in endothelial cells, adipocytes and fibroblasts. Caveolin-1 (Cav1), the signature structural protein of caveolae was the first protein associated with caveolae, and in association with Cavin1/PTRF is required for caveolae formation. Genetic ablation of either Cav1 or Cavin1/PTRF downregulates expression of the other resulting in loss of caveolae. Studies using Cav1-deficient mouse models have implicated caveolae with human diseases such as cardiomyopathies, lipodystrophies, diabetes and muscular dystrophies. While caveolins and caveolae are extensively studied in extra-ocular settings, their contributions to ocular function and disease pathogenesis are just beginning to be appreciated. Several putative caveolin/caveolae functions are relevant to the eye and Cav1 is highly expressed in retinal vascular and choroidal endothelium, Müller glia, the retinal pigment epithelium (RPE), and the Schlemm's canal endothelium and trabecular meshwork cells. Variants at the CAV1/2 gene locus are associated with risk of primary open angle glaucoma and the high risk HTRA1 variant for age-related macular degeneration is thought to exert its effect through regulation of Cav1 expression. Caveolins also play important roles in modulating retinal neuroinflammation and blood retinal barrier permeability. In this article, we describe the current state of caveolin/caveolae research in the context of ocular function and pathophysiology. Finally, we discuss new evidence showing that retinal Cav1 exists and functions outside caveolae.
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Affiliation(s)
- Eric N Enyong
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jami M Gurley
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael L De Ieso
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC, USA
| | - W Daniel Stamer
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC, USA
| | - Michael H Elliott
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Ophthalmology, Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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7
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Plastino F, Pesce NA, André H. MicroRNAs and the HIF/VEGF axis in ocular neovascular diseases. Acta Ophthalmol 2021; 99:e1255-e1262. [PMID: 33729690 DOI: 10.1111/aos.14845] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/18/2021] [Accepted: 02/23/2021] [Indexed: 12/28/2022]
Abstract
Ocular neovascular diseases, such as proliferative diabetic retinopathy, retinopathy of prematurity and neovascular age-related macular degeneration, are the leading causes of visual impairment worldwide. The hypoxia-inducible factors and vascular endothelial growth factors are key molecular promoters of ocular neovascularization. Moreover, the role of microRNAs as regulators of angiogenesis has been expanding, particularly hypoxia-associated microRNA; hypoxamiRs. This review provides a summary of hypoxamiRs that directly and specifically target HIF1A and VEGF mRNAs, thus critically involved in the regulation of ocular neovascular pathologies. The discussed microRNAs highlight putative diagnostic markers and therapeutic agents in choroidal and retinal angiogenic diseases, including proliferative diabetic retinopathy, retinopathy of prematurity and neovascular age-related macular degeneration.
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Affiliation(s)
- Flavia Plastino
- Department of Clinical Neurosciences Division of Eye and Vision St. Erik Eye Hospital Karolinska Institutet Stockholm Sweden
| | - Noemi Anna Pesce
- Department of Clinical Neurosciences Division of Eye and Vision St. Erik Eye Hospital Karolinska Institutet Stockholm Sweden
| | - Helder André
- Department of Clinical Neurosciences Division of Eye and Vision St. Erik Eye Hospital Karolinska Institutet Stockholm Sweden
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Lejoyeux R, Benillouche J, Ong J, Errera MH, Rossi EA, Singh SR, Dansingani KK, da Silva S, Sinha D, Sahel JA, Freund KB, Sadda SR, Lutty GA, Chhablani J. Choriocapillaris: Fundamentals and advancements. Prog Retin Eye Res 2021; 87:100997. [PMID: 34293477 DOI: 10.1016/j.preteyeres.2021.100997] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/02/2021] [Accepted: 07/13/2021] [Indexed: 12/19/2022]
Abstract
The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.
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Affiliation(s)
| | | | - Joshua Ong
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Marie-Hélène Errera
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ethan A Rossi
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
| | - Sumit R Singh
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, San Diego, CA, USA
| | - Kunal K Dansingani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Susana da Silva
- Department of Ophthalmology and Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - José-Alain Sahel
- Rothschild Foundation, 75019, Paris, France; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France
| | - K Bailey Freund
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, NY, USA; Vitreous Retina Macula Consultants of New York, New York, NY, USA; Department of Ophthalmology, New York University of Medicine, New York, NY, USA; Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA
| | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, 90033, USA; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gerard A Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, 21287, USA
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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Gama Sosa MA, De Gasperi R, Perez GM, Hof PR, Elder GA. Hemovasculogenic origin of blood vessels in the developing mouse brain. J Comp Neurol 2021; 529:340-366. [PMID: 32415669 DOI: 10.1002/cne.24951] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 05/05/2020] [Accepted: 05/08/2020] [Indexed: 01/20/2023]
Abstract
Vascular structures in the developing brain are thought to form via angiogenesis from preformed blood vessels in the cephalic mesenchyme. Immunohistochemical studies of developing mouse brain from E10.5 to E13.5 revealed the presence of avascular blood islands of primitive erythroid cells expressing hemangioblast markers (Flk1, Tal1/Scl1, platelet endothelial cell adhesion molecule 1, vascular endothelial-cadherin, and CD34) and an endothelial marker recognized by Griffonia simplicifolia isolectin B4 (IB4) in the cephalic mesenchyme. These cells formed a perineural vascular plexus from which angiogenic sprouts originated and penetrated the neuroepithelium. In addition, avascular isolated cells expressing primitive erythroid, hemangioblast and endothelial makers were visible in the neuroepithelium where they generated vasculogenic and hemogenic foci. From E10.5 to E13.5, these vasculogenic foci were a source of new blood vessel formation in the developing brain. In vitro, cultured E13.5 brain endothelial cells contained hemogenic endothelial cells capable of generating erythroid cells. Similar cells were present in primary cultures of dissociated cells from E10.5 embryonic head. Our results provide new evidence that the brain vasculature, like that of the yolk sac and the eye choriocapillaris and hyaloid vascular systems, develops at least in part via hemovasculogenesis, a process in which vasculogenesis and hematopoiesis occur simultaneously.
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Affiliation(s)
- Miguel A Gama Sosa
- General Medical Research Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Rita De Gasperi
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
| | - Gissel M Perez
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
| | - Patrick R Hof
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Gregory A Elder
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Neurology Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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10
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Edwards M, Lutty GA. Bruch's Membrane and the Choroid in Age-Related Macular Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1256:89-119. [PMID: 33847999 DOI: 10.1007/978-3-030-66014-7_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A healthy choroidal vasculature is necessary to support the retinal pigment epithelium (RPE) and photoreceptors, because there is a mutualistic symbiotic relationship between the components of the photoreceptor/retinal pigment epithelium (RPE)/Bruch's membrane (BrMb)/choriocapillaris (CC) complex. This relationship is compromised in age-related macular degeneration (AMD) by the dysfunction or death of the choroidal vasculature. This chapter will provide a basic description of the human Bruch's membrane and choroidal anatomy and physiology and how they change in AMD.The choriocapillaris is the lobular, fenestrated capillary system of choroid. It lies immediately posterior to the pentalaminar Bruch's membrane (BrMb). The blood supply for this system is the intermediate blood vessels of Sattler's layer and the large blood vessels in Haller's layer.In geographic atrophy (GA), an advanced form of dry AMD, large confluent drusen form on BrMb, and hyperpigmentation (presumably dysfunction in RPE) appears to be the initial insult. The resorption of these drusen and loss of RPE (hypopigmentation) can be predictive for progression of GA. The death and dysfunction of CC and photoreceptors appear to be secondary events to loss in RPE. The loss of choroidal vasculature may be the initial insult in neovascular AMD (nAMD). We have observed a loss of CC with an intact RPE monolayer in nAMD, by making RPE hypoxic. These hypoxic cells then produce angiogenic substances like vascular endothelial growth factor (VEGF), which stimulate growth of new vessels from CC, resulting in choroidal neovascularization (CNV). Reduction in blood supply to the CC, often stenosis of intermediate and large blood vessels, is associated with CC loss.The polymorphisms in the complement system components are associated with AMD. In addition, the environment of the CC, basement membrane and intercapillary septa, is a proinflammatory milieu with accumulation of proinflammatory molecules like CRP and complement components during AMD. In this toxic milieu, CC die or become dysfunctional even early in AMD. The loss of CC might be a stimulus for drusen formation since the disposal system for retinal debris and exocytosed material from RPE would be limited. Ultimately, the photoreceptors die of lack of nutrients, leakage of serum components from the neovascularization, and scar formation.Therefore, the mutualistic symbiotic relationship of the photoreceptor/RPE/BrMb/CC complex is lost in both forms of AMD. Loss of this functionally integrated relationship results in death and dysfunction of all of the components in the complex.
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Affiliation(s)
- Malia Edwards
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Gerard A Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, USA.
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11
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Single-cell RNA sequencing in vision research: Insights into human retinal health and disease. Prog Retin Eye Res 2020; 83:100934. [PMID: 33383180 DOI: 10.1016/j.preteyeres.2020.100934] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/27/2020] [Accepted: 12/01/2020] [Indexed: 01/03/2023]
Abstract
Gene expression provides valuable insight into cell function. As such, vision researchers have frequently employed gene expression studies to better understand retinal physiology and disease. With the advent of single-cell RNA sequencing, expression experiments provide an unparalleled resolution of information. Instead of studying aggregated gene expression across all cells in a heterogenous tissue, single-cell technology maps RNA to an individual cell, which facilitates grouping of retinal and choroidal cell types for further study. Single-cell RNA sequencing has been quickly adopted by both basic and translational vision researchers, and single-cell level gene expression has been studied in the visual systems of animal models, retinal organoids, and primary human retina, RPE, and choroid. These experiments have generated detailed atlases of gene expression and identified new retinal cell types. Likewise, single-cell RNA sequencing investigations have characterized how gene expression changes in the setting of many retinal diseases, including how choroidal endothelial cells are altered in age-related macular degeneration. In addition, this technology has allowed vision researchers to discover drivers of retinal development and model rare retinal diseases with induced pluripotent stem cells. In this review, we will overview the growing number of single-cell RNA sequencing studies in the field of vision research. We will summarize experimental considerations for designing single-cell RNA sequencing experiments and highlight important advancements in retinal, RPE, choroidal, and retinal organoid biology driven by this technology. Finally, we generalize these findings to genes involved in retinal degeneration and outline the future of single-cell expression experiments in studying retinal disease.
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Single-cell transcriptomics of the human retinal pigment epithelium and choroid in health and macular degeneration. Proc Natl Acad Sci U S A 2019; 116:24100-24107. [PMID: 31712411 PMCID: PMC6883845 DOI: 10.1073/pnas.1914143116] [Citation(s) in RCA: 205] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The retinal pigment epithelium and the choroid are complex tissues whose dysfunction can lead to irreversible visual loss. In this study, single-cell RNA sequencing of both of these tissues was performed to characterize gene expression patterns specific to the retinal pigment epithelium and all major choroidal cell populations. Unique gene expression signatures of arterial, venous, and choriocapillaris vascular beds within the choroid were identified. RGCC, a gene that responds to complement and has been shown to induce endothelial apoptosis, was specifically expressed in choriocapillaris endothelial cells. This study provides potential insight into the molecular mechanisms of choroidal vascular disease and its contribution to age-related macular degeneration. The human retinal pigment epithelium (RPE) and choroid are complex tissues that provide crucial support to the retina. Disease affecting either of these supportive tissues can lead to irreversible blindness in the setting of age-related macular degeneration. In this study, single-cell RNA sequencing was performed on macular and peripheral regions of RPE-choroid from 7 human donor eyes in 2 independent experiments. In the first experiment, total RPE/choroid preparations were evaluated and expression profiles specific to RPE and major choroidal cell populations were identified. As choroidal endothelial cells represent a minority of the total RPE/choroidal cell population but are strongly implicated in age-related macular degeneration (AMD) pathogenesis, a second single-cell RNA-sequencing experiment was performed using endothelial cells enriched by magnetic separation. In this second study, we identified gene expression signatures along the choroidal vascular tree, classifying the transcriptome of human choriocapillaris, arterial, and venous endothelial cells. We found that the choriocapillaris highly and specifically expresses the regulator of cell cycle gene (RGCC), a gene that responds to complement activation and induces apoptosis in endothelial cells. In addition, RGCC was the most up-regulated choriocapillaris gene in a donor diagnosed with AMD. These results provide a characterization of the human RPE and choriocapillaris transcriptome, offering potential insight into the mechanisms of choriocapillaris response to complement injury and choroidal vascular disease in age-related macular degeneration.
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Abstract
The retina is one of the most metabolically active tissues in the body, consuming high levels of oxygen and nutrients. A well-organized ocular vascular system adapts to meet the metabolic requirements of the retina to ensure visual function. Pathological conditions affect growth of the blood vessels in the eye. Understanding the neuronal biological processes that govern retinal vascular development is of interest for translational researchers and clinicians to develop preventive and interventional therapeutics for vascular eye diseases that address early drivers of abnormal vascular growth. This review summarizes the current knowledge of the cellular and molecular processes governing both physiological and pathological retinal vascular development, which is dependent on the interaction among retinal cell populations, including neurons, glia, immune cells, and vascular endothelial cells. We also review animal models currently used for studying retinal vascular development.
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Affiliation(s)
- Ye Sun
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts 02115, USA;
| | - Lois E H Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts 02115, USA;
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Galloway CA, Dalvi S, Shadforth AMA, Suzuki S, Wilson M, Kuai D, Hashim A, MacDonald LA, Gamm DM, Harkin DG, Singh R. Characterization of Human iPSC-RPE on a Prosthetic Bruch's Membrane Manufactured From Silk Fibroin. Invest Ophthalmol Vis Sci 2019; 59:2792-2800. [PMID: 30025113 PMCID: PMC5989661 DOI: 10.1167/iovs.17-23157] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Purpose RPE cell transplantation as a potential treatment for AMD has been extensively investigated; however, in AMD, ultrastructural damage affects both the RPE and its underlying matrix support, the Bruch's membrane (BrM). An RPE monolayer supported by a surrogate scaffold could thus provide a more effective approach to cell-based therapy for AMD. Toward this goal, we aimed to establish a functional human induced pluripotent stem cell-derived (hiPSC)-RPE monolayer on a Bombyx mori silk fibroin (BMSF) scaffold. Methods RPE differentiated from five distinct hiPSC lines were cultured on BMSF membrane coated with extracellular matrix (ECM, COL1), and either regular tissue culture plastic or Transwell coated with ECM (LAM-TCP). Morphologic, gene and protein expression, and functional characteristics of the hiPSC-RPE cultured on different membranes were compared in longitudinal experiments spanning 1 day to ≥3 months. Results The hiPSC-RPE monolayers on ECM-coated BMSF and TCP could be maintained in culture for ≥3 months and displayed RPE-characteristic morphology, pigmentation, polarity, and expression of RPE signature genes and proteins. Furthermore, hiPSC-RPE on both ECM-coated BMSF and TCP displayed robust expression and secretion of several basement membrane proteins. Importantly, hiPSC-RPE cells on COL1-BMSF and LAM-TCP showed similar efficacy in the phagocytosis and degradation of photoreceptor outer segments. Conclusions A biomaterial scaffold manufactured from silk fibroin supports the maturation and long-term survival of a functional hiPSC-RPE monolayer. This has significant implications for both in vitro disease modeling and in vivo cell replacement therapy.
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Affiliation(s)
- Chad A Galloway
- Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, New York, United States.,Department of Biomedical Genetics, University of Rochester, Rochester, New York, United States
| | - Sonal Dalvi
- Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, New York, United States.,Department of Biomedical Genetics, University of Rochester, Rochester, New York, United States
| | - Audra M A Shadforth
- Queensland Eye Institute, South Brisbane, Queensland, Australia.,School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Shuko Suzuki
- Queensland Eye Institute, South Brisbane, Queensland, Australia
| | - Molly Wilson
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States
| | - David Kuai
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States
| | - Ali Hashim
- Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, New York, United States.,Department of Biomedical Genetics, University of Rochester, Rochester, New York, United States
| | - Leslie A MacDonald
- Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, New York, United States.,Department of Biomedical Genetics, University of Rochester, Rochester, New York, United States
| | - David M Gamm
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States.,Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States.,McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States
| | - Damien G Harkin
- Queensland Eye Institute, South Brisbane, Queensland, Australia.,School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Ruchira Singh
- Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, New York, United States.,Department of Biomedical Genetics, University of Rochester, Rochester, New York, United States.,Center for Visual Science, University of Rochester, Rochester, New York, United States.,Univeristy of Rochester Stem Cell and Regenerative Medicine Institute, Rochester, New York, United States
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Lutty GA, McLeod DS. Development of the hyaloid, choroidal and retinal vasculatures in the fetal human eye. Prog Retin Eye Res 2018; 62:58-76. [PMID: 29081352 PMCID: PMC5776052 DOI: 10.1016/j.preteyeres.2017.10.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/03/2017] [Accepted: 10/09/2017] [Indexed: 01/06/2023]
Abstract
The development of the ocular vasculatures is perfectly synchronized to provide the nutritional and oxygen requirements of the forming human eye. The fetal vasculature of vitreous, which includes the hyaloid vasculature, vasa hyaloidea propria, and tunica vasculosa lentis, initially develops around 4-6 weeks gestation (WG) by hemo-vasculogenesis (development of blood and blood vessels from a common progenitor, the hemangioblast). This transient fetal vasculature expands around 12 WG by angiogenesis (budding from primordial vessels) and remains until a retinal vasculature begins to form. The fetal vasculature then regresses by apoptosis with the assistance of macrophages/hyalocytes. The human choroidal vasculature also forms by a similar process and will supply nutrients and oxygen to outer retina. This lobular vasculature develops in a dense collagenous tissue juxtaposed with a cell constitutively producing vascular endothelial growth factor (VEGF), the retinal pigment epithelium. This epithelial/endothelial relationship is critical in maintaining the function of this vasculature throughout life and maintaining it's fenestrated state. The lobular capillary system (choriocapillaris) develops first by hemo-vasculogenesis and then the intermediate choroidal blood vessels form by angiogenesis, budding from the choriocapillaris. The human retinal vasculature is the last to develop. It develops by vasculogenesis, assembly of CXCR4+/CD39+ angioblasts or vascular progenitors perhaps using Muller cell Notch1 or axonal neuropilinin-1 for guidance of semaphorin 3A-expressing angioblasts. The fovea never develops a retinal vasculature, which is probably due to the foveal avascular zone area of retina expressing high levels of antiangiogenic factors. From these studies, it is apparent that development of the mouse ocular vasculatures is not representative of the development of the human fetal, choroidal and retinal vasculatures.
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Affiliation(s)
- Gerard A Lutty
- Wilmer Ophthalmological Institute, Baltimore, MD 21287, United States.
| | - D Scott McLeod
- Wilmer Ophthalmological Institute, Baltimore, MD 21287, United States
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16
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McLeod DS, Bhutto I, Edwards MM, Gedam M, Baldeosingh R, Lutty GA. Mast Cell-Derived Tryptase in Geographic Atrophy. Invest Ophthalmol Vis Sci 2017; 58:5887-5896. [PMID: 29164232 PMCID: PMC5699534 DOI: 10.1167/iovs.17-22989] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 10/14/2017] [Indexed: 11/25/2022] Open
Abstract
Purpose Our previous study demonstrated significantly more degranulating mast cells (MCs) in choroids from subjects with age-related macular degeneration compared to aged controls. This study examined the immunolocalization of tryptase, the most abundant MC secretory granule-derived serine protease, in aged control eyes and eyes with geographic atrophy (GA). Methods Postmortem human eyes with and without GA were obtained from the National Disease Research Interchange. Tissue was fixed, cryopreserved, sectioned, and immunostained with a monoclonal antibody against tryptase. Sections were imaged on a Zeiss 710 Confocal Microscope. Results In the posterior pole of all aged control eyes, tryptase was confined to choroidal MCs, which were located primarily in Sattler's layer. In eyes with GA, many MCs were located in the inner choroid near choriocapillaris and Bruch's membrane (BM). Tryptase was found not only in MCs but also diffusely around them in stroma, suggesting they had degranulated. In contrast with aged control eyes, eyes with GA also had strong tryptase staining in BM. Tryptase was observed within BM in regions of RPE atrophy, at the border of atrophy, and extending well into the nonatrophic region. Conclusions Our results demonstrate that tryptase, released during choroidal MC degranulation, binds to BM in GA in advance of RPE atrophy. Tryptase activates MMPs that can degrade extracellular matrix (ECM) and basement membrane components found in BM. ECM modifications are likely to have a profound effect on the function and health of RPE and choroidal thinning in GA.
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Affiliation(s)
- D. Scott McLeod
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States
| | - Imran Bhutto
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States
| | - Malia M. Edwards
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States
| | - Manasee Gedam
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States
| | - Rajkumar Baldeosingh
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States
| | - Gerard A. Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States
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Chirco KR, Sohn EH, Stone EM, Tucker BA, Mullins RF. Structural and molecular changes in the aging choroid: implications for age-related macular degeneration. Eye (Lond) 2017; 31:10-25. [PMID: 27716746 PMCID: PMC5233940 DOI: 10.1038/eye.2016.216] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/06/2016] [Indexed: 12/27/2022] Open
Abstract
Age-related macular degeneration (AMD) is a devastating disease-causing vision loss in millions of people around the world. In advanced stages of disease, death of photoreceptor cells, retinal pigment epithelial cells, and choroidal endothelial cells (CECs) are common. Loss of endothelial cells of the choriocapillaris is one of the earliest detectable events in AMD, and, because the outer retina relies on the choriocapillaris for metabolic support, this loss may be the trigger for progression to more advanced stages. Here we highlight evidence for loss of CECs, including changes to vascular density within the choriocapillaris, altered abundance of CEC markers, and changes to overall thickness of the choroid. Furthermore, we review the key components and functions of the choroid, as well as Bruch's membrane, both of which are vital for healthy vision. We discuss changes to the structure and molecular composition of these tissues, many of which develop with age and may contribute to AMD pathogenesis. For example, a crucial event that occurs in the aging choriocapillaris is accumulation of the membrane attack complex, which may result in complement-mediated CEC lysis, and may be a primary cause for AMD-associated choriocapillaris degeneration. The actions of elevated monomeric C-reactive protein in the choriocapillaris in at-risk individuals may also contribute to the inflammatory environment in the choroid and promote disease progression. Finally, we discuss the progress that has been made in the development of AMD therapies, with a focus on cell replacement.
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Affiliation(s)
- K R Chirco
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, IA, USA
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA
| | - E H Sohn
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, IA, USA
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA
| | - E M Stone
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, IA, USA
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA
| | - B A Tucker
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, IA, USA
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA
| | - R F Mullins
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, Iowa City, IA, USA
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA
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Nakanishi M, Grebe R, Bhutto IA, Edwards M, McLeod DS, Lutty GA. Albumen Transport to Bruch's Membrane and RPE by Choriocapillaris Caveolae. Invest Ophthalmol Vis Sci 2016; 57:2213-24. [PMID: 27116549 PMCID: PMC4849865 DOI: 10.1167/iovs.15-17934] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PURPOSE The choriocapillaris (CC), the capillary network of the choroid, is positioned adjacent to Bruch's membrane (BM) and the RPE. The aim of this study was to clarify the mechanism(s) for transport of serum albumen from CC lumen to RPE. METHODS Alexa647 conjugated to BSA (BSA-A647) or PBS was administrated via the femoral vein to young and aged wild-type (WT; C57BL/6J) mice and Caveolin-1 knockout mice (Cav1(-/-)). Mice were perfused with PBS and killed at 30 minutes, 1 hour, and 4 hours after injection. Eyecups were cryopreserved, and cryosections were analyzed on a Zeiss 710 confocal microscope. Bovine serum albumin conjugated to gold nanoparticles (BSA-GNP) was administrated through the left common carotid artery. Mice were perfused with PBS and killed at 30 minutes after injection. Eyecups were embedded after fixation, and 70-nm-thick sections were analyzed on a Hitachi H7600 transmission electron microscope. RESULTS In eyes of WT young mice, BSA-A647 was transported to the RPE at 30 minutes and diffused to the photoreceptor layer by 1 hour. In contrast, most BSA-A647 was found in the CC in Cav1(-/-) eyes. The majority of BSA-GNP found in the CC of young WT mice was on the luminal side in caveolae at 30 minutes after injection. In aged WT mice, BSA-GNPs were found in defective tight junctions between endothelial cells and appeared trapped at the diaphragm of fenestrations. CONCLUSIONS Normally, CC carefully regulates transport system of BSA from lumen to BM by caveolae-mediated transcytosis; however, endothelium cells of aged control WT mice have leaky tight junctions and lacked regulated BSA transport.
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Hu Y, Li M, Göthert JR, Gomez RA, Sequeira-Lopez MLS. Hemovascular Progenitors in the Kidney Require Sphingosine-1-Phosphate Receptor 1 for Vascular Development. J Am Soc Nephrol 2015; 27:1984-95. [PMID: 26534925 DOI: 10.1681/asn.2015060610] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/03/2015] [Indexed: 02/05/2023] Open
Abstract
The close relationship between endothelial and hematopoietic precursors during early development of the vascular system suggested the possibility of a common yet elusive precursor for both cell types. Whether similar or related progenitors for endothelial and hematopoietic cells are present during organogenesis is unclear. Using inducible transgenic mice that specifically label endothelial and hematopoietic precursors, we performed fate-tracing studies combined with colony-forming assays and crosstransplantation studies. We identified a progenitor, marked by the expression of helix-loop-helix transcription factor stem cell leukemia (SCL/Tal1). During organogenesis of the kidney, SCL/Tal1(+) progenitors gave rise to endothelium and blood precursors with multipotential colony-forming capacity. Furthermore, appropriate morphogenesis of the kidney vasculature, including glomerular capillary development, arterial mural cell coating, and lymphatic vessel development, required sphingosine 1-phosphate (S1P) signaling via the G protein-coupled S1P receptor 1 in these progenitors. Overall, these results show that SCL/Tal1(+) progenitors with hemogenic capacity originate and differentiate within the early embryonic kidney by hemovasculogenesis (the concomitant formation of blood and vessels) and underscore the importance of the S1P pathway in vascular development.
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Affiliation(s)
- Yan Hu
- Department of Pediatrics and Department of Biology, University of Virginia, Charlottesville, Virginia; and
| | | | - Joachim R Göthert
- Department of Hematology, West German Cancer Center, University Hospital Essen, Essen, Germany
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Whitmore SS, Sohn EH, Chirco KR, Drack AV, Stone EM, Tucker BA, Mullins RF. Complement activation and choriocapillaris loss in early AMD: implications for pathophysiology and therapy. Prog Retin Eye Res 2015; 45:1-29. [PMID: 25486088 PMCID: PMC4339497 DOI: 10.1016/j.preteyeres.2014.11.005] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 11/19/2014] [Accepted: 11/25/2014] [Indexed: 12/24/2022]
Abstract
Age-related macular degeneration (AMD) is a common and devastating disease that can result in severe visual dysfunction. Over the last decade, great progress has been made in identifying genetic variants that contribute to AMD, many of which lie in genes involved in the complement cascade. In this review we discuss the significance of complement activation in AMD, particularly with respect to the formation of the membrane attack complex in the aging choriocapillaris. We review the clinical, histological and biochemical data that indicate that vascular loss in the choroid occurs very early in the pathogenesis of AMD, and discuss the potential impact of vascular dropout on the retinal pigment epithelium, Bruch's membrane and the photoreceptor cells. Finally, we present a hypothesis for the pathogenesis of early AMD and consider the implications of this model on the development of new therapies.
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Affiliation(s)
- S Scott Whitmore
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Elliott H Sohn
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Kathleen R Chirco
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Arlene V Drack
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Edwin M Stone
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Budd A Tucker
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
| | - Robert F Mullins
- The Stephen A. Wynn Institute for Vision Research, The University of Iowa, United States; Department of Ophthalmology and Visual Sciences, The University of Iowa, United States
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McLeod DS, Hasegawa T, Baba T, Grebe R, Galtier d'Auriac I, Merges C, Edwards M, Lutty GA. From blood islands to blood vessels: morphologic observations and expression of key molecules during hyaloid vascular system development. Invest Ophthalmol Vis Sci 2012; 53:7912-27. [PMID: 23092923 DOI: 10.1167/iovs.12-10140] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE The mode of development of the human hyaloid vascular system (HVS) remains unclear. Early studies suggested that these blood vessels formed by vasculogenesis, while the current concept seems to favor angiogenesis as the mode of development. We examined embryonic and fetal human HVS using a variety of techniques to gain new insights into formation of this vasculature. METHODS Embryonic and fetal human eyes from 5.5 to 12 weeks gestation (WG) were prepared for immunohistochemical analysis or for light and electron microscopy. Immunolabeling of sections with a panel of antibodies directed at growth factors, transcription factors, and hematopoietic stem cell markers was employed. RESULTS Light microscopic examination revealed free blood islands (BI) in the embryonic vitreous cavity (5.5-7 WG). Giemsa stain revealed that BI were aggregates of mesenchymal cells and primitive nucleated erythroblasts. Free cells were also observed. Immunolabeling demonstrated that BI were composed of mesenchymal cells that expressed hemangioblast markers (CD31, CD34, C-kit, CXCR4, Runx1, and VEGFR2), erythroblasts that expressed embryonic hemoglobin (Hb-ε), and cells that expressed both. Few cells were proliferating as determined by lack of Ki67 antigen. As development progressed (12 WG), blood vessels became more mature structurally with pericyte investment and basement membrane formation. Concomitantly, Hb-ε and CXCR4 expression was down-regulated and von Willebrand factor expression was increased with the formation of Weibel-Palade bodies. CONCLUSIONS Our results support the view that the human HVS, like the choriocapillaris, develops by hemo-vasculogenesis, the process by which vasculogenesis, erythropoiesis, and hematopoiesis occur simultaneously from common precursors, hemangioblasts.
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Kur J, Newman EA, Chan-Ling T. Cellular and physiological mechanisms underlying blood flow regulation in the retina and choroid in health and disease. Prog Retin Eye Res 2012; 31:377-406. [PMID: 22580107 DOI: 10.1016/j.preteyeres.2012.04.004] [Citation(s) in RCA: 448] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/17/2012] [Accepted: 04/22/2012] [Indexed: 02/06/2023]
Abstract
We review the cellular and physiological mechanisms responsible for the regulation of blood flow in the retina and choroid in health and disease. Due to the intrinsic light sensitivity of the retina and the direct visual accessibility of fundus blood vessels, the eye offers unique opportunities for the non-invasive investigation of mechanisms of blood flow regulation. The ability of the retinal vasculature to regulate its blood flow is contrasted with the far more restricted ability of the choroidal circulation to regulate its blood flow by virtue of the absence of glial cells, the markedly reduced pericyte ensheathment of the choroidal vasculature, and the lack of intermediate filaments in choroidal pericytes. We review the cellular and molecular components of the neurovascular unit in the retina and choroid, techniques for monitoring retinal and choroidal blood flow, responses of the retinal and choroidal circulation to light stimulation, the role of capillaries, astrocytes and pericytes in regulating blood flow, putative signaling mechanisms mediating neurovascular coupling in the retina, and changes that occur in the retinal and choroidal circulation during diabetic retinopathy, age-related macular degeneration, glaucoma, and Alzheimer's disease. We close by discussing issues that remain to be explored.
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Affiliation(s)
- Joanna Kur
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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McLeod DS, Baba T, Bhutto IA, Lutty GA. Co-expression of endothelial and neuronal nitric oxide synthases in the developing vasculatures of the human fetal eye. Graefes Arch Clin Exp Ophthalmol 2012; 250:839-48. [PMID: 22411126 DOI: 10.1007/s00417-012-1969-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/15/2012] [Accepted: 02/10/2012] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Nitric oxide (NO) is a multifunctional gaseous molecule that regulates various physiological functions in both neuronal and non-neuronal cells. NO is synthesized by nitric oxide synthases (NOSs), of which three isoforms have been identified. Neuronal NOS (nNOS) and endothelial NOS (eNOS) constitutively produce low levels of NO as a cell-signaling molecule in response to an increase in intracellular calcium concentration. Recent data have revealed a predominant role of eNOS in both angiogenesis and vasculogenesis. METHODS The immunohistochemical localization of nNOS and eNOS was investigated during embryonic and fetal ocular vascular development from 7 to 21 weeks gestation (WG) on sections of cryopreserved tissue. RESULTS eNOS was confined to endothelial cells of developing vessels at all ages studied. nNOS was prominent in nuclei of vascular endothelial and smooth muscle cells in the fetal vasculature of vitreous and choriocapillaris. nNOS was also prominent in the nuclei of CXCR4(+) progenitors in the inner retina and inner neuroblastic layer. CONCLUSIONS These findings demonstrate co-expression of n- and eNOS isoforms in different compartments of vasoformative cells during development. Nuclear nNOS was present in vascular and nonvascular progenitors as well as endothelial cells and pericytes. This suggests that nNOS may play a role in the transcription regulatory systems in endothelial cells and pericytes during ocular hemo-vasculogenesis, vasculogenesis, and angiogenesis.
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Affiliation(s)
- D Scott McLeod
- Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, M041 Smith Research Building, 400 North Broadway, Baltimore, MD 21287, USA
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Baba T, McLeod DS, Edwards MM, Merges C, Sen T, Sinha D, Lutty GA. VEGF 165 b in the developing vasculatures of the fetal human eye. Dev Dyn 2012; 241:595-607. [PMID: 22275161 DOI: 10.1002/dvdy.23743] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2012] [Indexed: 12/19/2022] Open
Abstract
VEGF(165) b is an anti-angiogenic form of VEGF(165) produced by alternative splicing. The localization of pro-angiogenic VEGF(165) and anti-angiogenic VEGF(165) b was investigated during development of the vasculatures in fetal human eyes from 7 to 21 weeks gestation (WG). The fetal vasculature of vitreous, which includes tunica vasculosa lentis (TVL), had moderate VEGF(165) immunoreactivity at 7WG and very little VEGF(165) b. Both forms were elevated at 12WG. VEGF(165) then decreased around 17WG when the TVL regresses but VEGF(165) b remained elevated. In choroid, VEGF(165) was present in forming choriocapillaris (CC) and retinal pigment epithelium (RPE) at 7WG while VEGF165b was present in CC and mesenchymal precursors within the choroidal stroma. By 21WG, both forms were elevated in RPE and choroidal blood vessels but VEGF(165) b was apical and VEGF(165) basal in RPE. Diffuse VEGF(165) immunoreactivity was prominent in 12WG innermost retina where blood vessels will form while VEGF(165) b was present in most CXCR4(+) progenitors in the inner neuroblastic layer and migrating angioblasts in the putative nerve fiber layer. By 21WG, VEGF(165) was present in nerve fibers and VEGF(165) b in the inner Muller cell process. The localization of VEGF(165) b was distinctly different from VEGF(165) both spatially and temporally and it was often associated with nucleus in progenitors.
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Affiliation(s)
- Takayuki Baba
- Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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Wary KK, Kohler EE, Chatterjee I. Focal adhesion kinase regulation of neovascularization. Microvasc Res 2012; 83:64-70. [PMID: 21616084 PMCID: PMC3186864 DOI: 10.1016/j.mvr.2011.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/04/2011] [Accepted: 05/06/2011] [Indexed: 11/22/2022]
Abstract
In this review, we discuss the role of focal adhesion kinase (FAK), an intracellular tyrosine kinase, in endothelial cells in relation to neovascularization. Genetic and in vitro studies have identified critical factors, receptor systems, and their intracellular signaling components that regulate the neovasculogenic phenotypes of endothelial cells. Among these factors, FAK appears to regulate several aspects of endothelial cellular behavior, including migration, survival, cytoskeletal organization, as well as cell proliferation. Upon adhesion of endothelial cells to extracellular matrix (ECM) ligands, integrins cluster on the plane of plasma-membrane, while cytoplasmic domains of integrins interact with cytoskeletal proteins and signaling molecules including FAK. However, FAK not only serves as a critical component of integrin signaling, but is also a downstream element of the VEGF/VEGF-receptor and other ligand-receptor systems that regulate neovascularization. A complete understanding of FAK-mediated neovascularization, therefore, should address the molecular and cellular mechanisms that regulate the biology of FAK. Continued research on FAK may, therefore, yield novel therapies to improve treatment modalities for the pathological neovascularization associated with diseases.
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Affiliation(s)
- Kishore K Wary
- Department of Pharmacology, University of Illinois, 835 S. Wolcott, Room E403, Mail code 868, Chicago, IL 60612, USA.
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Lama1 mutations lead to vitreoretinal blood vessel formation, persistence of fetal vasculature, and epiretinal membrane formation in mice. BMC DEVELOPMENTAL BIOLOGY 2011; 11:60. [PMID: 21999428 PMCID: PMC3215647 DOI: 10.1186/1471-213x-11-60] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 10/14/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND Valuable insights into the complex process of retinal vascular development can be gained using models with abnormal retinal vasculature. Two such models are the recently described mouse lines with mutations in Lama1, an important component of the retinal internal limiting membrane (ILM). These mutants have a persistence of the fetal vasculature of vitreous (FVV) but lack a primary retinal vascular plexus. The present study provides a detailed analysis of astrocyte and vascular development in these Lama1 mutants. RESULTS Although astrocytes and blood vessels initially migrate into Lama1 mutant retinas, both traverse the peripapillary ILM into the vitreous by P3. Once in the vitreous, blood vessels anastomose with vessels of the vasa hyaloidea propria, part of the FVV, and eventually re-enter the retina where they dive to form the inner and outer retinal capillary networks. Astrocytes continue proliferating within the vitreous to form a dense mesh that resembles epiretinal membranes associated with persistent fetal vasculature and proliferative vitreoretinopathy. CONCLUSIONS Lama1 and a fully intact ILM are required for normal retinal vascular development. Mutations in Lama1 allow developing retinal vessels to enter the vitreous where they anastomose with vessels of the hyaloid system which persist and expand. Together, these vessels branch into the retina to form fairly normal inner retinal vascular capillary plexi. The Lama1 mutants described in this report are potential models for studying the human conditions persistent fetal vasculature and proliferative vitreoretinopathy.
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Ebrahem Q, Qi JH, Sugimoto M, Ali M, Sears JE, Cutler A, Khokha R, Vasanji A, Anand-Apte B. Increased neovascularization in mice lacking tissue inhibitor of metalloproteinases-3. Invest Ophthalmol Vis Sci 2011; 52:6117-23. [PMID: 21282576 DOI: 10.1167/iovs.10-5899] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Tissue inhibitor of metalloproteinases-3 (TIMP-3) is a matrix-bound inhibitor of matrix metalloproteinases (MMPs). The authors have previously determined a novel function of TIMP-3 to inhibit vascular endothelial growth factor (VEGF)-mediated angiogenesis. Here, the authors examined the in vivo angiogenic phenotype of ocular vessels in mice deficient in TIMP-3. METHODS VEGF-mediated corneal neovascularization and laser-induced choroidal neovascularization (CNV) were examined in TIMP-3-null mice. The effects of the absence of TIMP-3 on the phosphorylation status of the VEGF-receptor-2 (VEGFR-2) and the downstream signaling pathways were evaluated biochemically. In addition, the activation state of MMPs in the retina of TIMP-3-deficient mice was examined by in situ zymography. RESULTS The results of these studies determine an accentuation of pathologic VEGF-mediated angiogenesis in the cornea and laser-induced CNV in mice lacking TIMP-3. In the absence of the MMP inhibitor, pathophysiological changes were observed in the choroidal vasculature concomitantly with an increase in gelatinolytic activity. These results suggest that an imbalance of extracellular matrix homeostasis, together with a loss of an angiogenesis inhibitor, can prime vascular beds to be more responsive to an angiogenic stimulus. CONCLUSIONS In light of the recent studies suggesting that genetic variants near TIMP-3 influence susceptibility to age-related macular degeneration, these results imply that TIMP-3 may regulate the development of the choroidal vasculature and is a likely contributor to increased susceptibility to choroidal neovascularization.
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Affiliation(s)
- Quteba Ebrahem
- Department of Ophthalmology, Cole Eye Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195, USA
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Evidence of hematopoietic differentiation, vasculogenesis and angiogenesis in the formation of human choroidal blood vessels. Exp Eye Res 2011; 92:361-76. [PMID: 21354137 DOI: 10.1016/j.exer.2011.02.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 12/01/2010] [Accepted: 02/15/2011] [Indexed: 11/20/2022]
Abstract
Human fetal eyes 8-40 weeks gestation (WG) were examined using markers to hematopoietic stem cells (HSC), vascular precursor cells (VPC), monocytes/macrophages and endothelial cells (EC). Electron microscopy and bromo-deoxyuridene labeling were undertaken to confirm the existence of solid vascular cords and to demonstrate vasculogenesis and angiogenesis in developing choroidal tissue. Our results demonstrated that the earliest incipient choroid consisted of vimentin(+) mesenchymal precursor cells which downregulated vimentin expression with maturation. Our observations lead us to conclude that these vimentin(-)/CD34(+)/CD44(+)/CD133(+) HSCs then differentiated into three distinct lineages: single isolated CD34(-)/CD39(+) VPCs that formed solid vascular cords which lumenized and became lined with CD34(+) vascular ECs; CD34(--+)/CD14(+)/CD68(+) monocytes that differentiated into tissue macrophages; and CD133(+)/CD34(--+)/α-smooth muscle actin(+) mural precursor cells that matured into smooth muscle cells and pericytes. Blood vessel formation occurred throughout the whole choroid simultaneously, indicative of in situ differentiation. Vasculogenesis, as evidenced by lumenization of solid vascular cords, was responsible for the formation of the entire choroidal area with angiogenesis, in all three layers of the choroid, only adding to vascular density. These results suggest that formation of the human choroid involves three processes: HSC differentiation, vasculogenesis and angiogenesis. Since vasculogenesis takes place independently of VEGF(165), further insights regarding the molecular mechanisms of vasculogenesis are required to better inform future treatments of choroidal neovascularization.
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Lutty GA, Hasegawa T, Baba T, Grebe R, Bhutto I, McLeod DS. Development of the human choriocapillaris. Eye (Lond) 2010; 24:408-15. [PMID: 20075975 PMCID: PMC4848024 DOI: 10.1038/eye.2009.318] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Vasculogenesis and/or angiogenesis are thought to be the major mechanisms for new vessel formation during development. A third mechanism, haemo-vasculogenesis, has been described in which blood vessel and blood cells (haematopoiesis (expression of CD34(+)) and erythropoiesis (presence of epsilon chain of haemoglobin or Hb-epsilon(+))) differentiate from a common precursor, the haemangioblast. This review describes the mechanism(s) for development of human choroidal vascular from 6 until 22 weeks gestation (WG). Endothelial cell or EC (CD31, CD34, CD39, VEGFR-2) and angioblast (CD39, VEGFR-2) markers were present in choriocapillaris (CC) by 7 WG through 22 WG. From 6 to 8 WG, many erythroblasts (nucleated Hb-epsilon(+) RBCs) were observed in the CC layer. Erythroblasts (Hb-epsilon(+)) were also positive for CD34, CD31, and/or VEGFR-2. Proliferation of vascular cells (Ki67+), suggesting angiogenesis, was not observed until 12 WG. TEM analysis demonstrated that CC was structurally immature even at 11 WG: no basement membrane, absence of pericytes, and poorly formed lumens that were filled with filopodia. Contiguous fenestrations and significant PV-1 (protein in diaphragms of fenestrations) were not observed until 21-22 WG. Smooth muscle actin was prominent at 20 WG and the maturation of pericytes was confirmed by TEM. Therefore, the embryonic CC appears to form initially by haemo-vasculogenesis (Hb-epsilon(+)/CD31(+) cells), whereas angiogenesis (CD34(+)/Ki67(+)) appears to be the mode of intermediate and large choroidal vessel development later in the foetus. Contiguous fenestrations, mature pericytes, and EC basal lamina occur late in development, around 22 WG, which coincides with photoreceptors developing inner segments.
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Affiliation(s)
- G A Lutty
- Department of Ophthalmology, Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD 21287-9115, USA.
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Mancini ML, Terzic A, Conley BA, Oxburgh LH, Nicola T, Vary CPH. Endoglin plays distinct roles in vascular smooth muscle cell recruitment and regulation of arteriovenous identity during angiogenesis. Dev Dyn 2010; 238:2479-93. [PMID: 19705428 DOI: 10.1002/dvdy.22066] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Blood vessel formation is a multi-step process. Endoglin is a TGFbeta coreceptor required for angiogenesis. Endoglin null embryos exhibit a loss of arteriovenous identity and defective vascular smooth muscle cell (vSMC) recruitment. Haploinsufficiency of endoglin results in Hereditary Hemorrhagic Telangiectasia (HHT), characterized by a loss of arteriovenous identity and aberrant vSMC incorporation in fragile vessels. We explored a cell-autonomous role for endoglin in endothelial and vSMCs during angiogenesis by conditionally activating endoglin expression in wild type or endoglin null embryos using either smooth muscle (SM22alphacre) or endothelial cell (Tie2cre) promoters to partially rescue vSMC recruitment to the dorsal aorta. Examination of endoglin null embryos revealed ectopic arterial expression of the venous-specific marker COUPTFII. Endoglin re-expression in endothelial cells restored normal COUPTFII expression. These results suggested that endoglin plays distinct and cell-autonomous roles in vSMC recruitment and arteriovenous specification via COUPTFII in angiogenesis that may contribute to HHT.
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Affiliation(s)
- Maria L Mancini
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, USA
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Baba T, Grebe R, Hasegawa T, Bhutto I, Merges C, McLeod DS, Lutty GA. Maturation of the fetal human choriocapillaris. Invest Ophthalmol Vis Sci 2009; 50:3503-11. [PMID: 19264887 DOI: 10.1167/iovs.08-2614] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to examine the structural and functional maturation of the choriocapillaris (CC) and to determine when fenestrations form, the capillaries are invested with pericytes, and the endothelial cells (ECs) became functional. METHODS Immunohistochemistry was performed on cryopreserved sections of embryonic/fetal human eyes from 7 to 22 weeks' gestation (WG), using antibodies against PAL-E, PV-1 (fenestrations), carbonic anhydrase IV (CA IV), eNOS, and alpha-smooth muscle actin (alphaSMA) and NG2 (two pericyte markers) and the EC marker (CD31). Alkaline phosphatase (APase) enzymatic activity was demonstrated by enzyme histochemistry. Transmission electron microscopy (TEM) was performed on eyes at 11, 14, 16, and 22 WG. Adult human eyes were used as the positive control. RESULTS All EC markers were present in the CC by 7 WG. PAL-E, CA IV, and eNOS immunoreactivities and APase activity were present in the CC by 7 to 9 WG. TEM analysis demonstrated how structurally immature this vasculature was, even at 11 WG: no basement membrane, absence of pericytes, and poorly formed lumens that were filled with filopodia. The few fenestrations that were observed were often present within the luminal space in the filopodia. Contiguous fenestrations and significant PV-1 were not observed until 21 to 22 WG. alphaSMA was prominent at 22 WG, and the maturation of pericytes was confirmed by TEM. CONCLUSIONS It appears that ECs and their precursors express enzymes present in adult CC well before they are structurally mature. Although ECs make tight junctions early in development, contiguous fenestrations and mature pericytes occur much later in development.
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Affiliation(s)
- Takayuki Baba
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland 21287-9115, USA
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Hasegawa T, McLeod DS, Prow T, Merges C, Grebe R, Lutty GA. Vascular precursors in developing human retina. Invest Ophthalmol Vis Sci 2008; 49:2178-92. [PMID: 18436851 DOI: 10.1167/iovs.07-0632] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Prior investigation has demonstrated that angioblasts are present in the inner retinas of human embryos and fetuses and that they differentiate and organize to form the primordial retinal vasculature. The purpose of this study was to characterize these angioblasts further and examine ligands that might control their migration and differentiation. METHODS Immunohistochemistry was used to localize stroma-derived factor-1 (SDF-1), its receptor CXCR4, stem cell factor (SCF), and its receptor c-Kit on sections obtained from human eyes at from 6 to 23 weeks' gestation (WG). Coexpression of CD39 (marker for retinal angioblasts and endothelial cells) and CXCR4 or c-Kit was investigated by confocal microscopy. RESULTS SDF-1 was prominent in inner retina with the greatest reaction product near the internal limiting membrane (ILM). SCF immunoreactivity was also confined to the inner retina and increased significantly between 7 and 12 WG. The level of both ligands declined by 22 WG. A layer of CXCR4(+) and c-Kit(+) precursors, some of which coexpressed CD39, existed in the inner retina from 7 to 12 WG. With migration, c-Kit was downregulated, whereas CD39(+) cells continued to express CXCR4 as they formed cords. With canalization, CXCR4 expression was downregulated. CONCLUSIONS Embryonic human retina has a pool of precursors (CXCR4(+) and c-Kit(+)) that enlarged centrifugally during fetal development. From this pool emerges angioblasts, which migrate anteriorly into the nerve fiber layer where SDF-1 and SCF levels are highest. c-Kit expression declines with apparent migration, and CXCR4 expression declines with canalization of new vessels. Both SCF and SDF-1 are associated with the differentiation of retinal precursors into angioblasts and their migration to sites of vessel assembly.
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Affiliation(s)
- Takuya Hasegawa
- Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Sundin OH, Dharmaraj S, Bhutto IA, Hasegawa T, McLeod DS, Merges CA, Silval ED, Maumenee IH, Lutty GA. Developmental basis of nanophthalmos: MFRP Is required for both prenatal ocular growth and postnatal emmetropization. Ophthalmic Genet 2008; 29:1-9. [PMID: 18363166 DOI: 10.1080/13816810701651241] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Nanophthalmos is a genetic disorder characterized by very small, hyperopic eyes that are without gross structural defects. Recessive nanophthalmos is caused by severe mutations in the MFRP gene, which encodes a Frizzled-related transmembrane protein that is selectively expressed in the retinal pigment epithelium (RPE) and ciliary body. RESULTS For two MFRP -/- adults, we have obtained records of refraction that begin in early childhood. At the age of 6 months, one patient's eyes already had a refractive error of +12.25 D, and over the next 20 years this slowly increased to +17.50 D. Adults homozygous for null mutations in MFRP have eyes with axial lengths shorter than those of normal newborns. Furthermore, the unusually high curvature of their corneas is consistent with eyes that had been smaller than normal during late fetal development. MFRP protein was first detected at 14 weeks of gestation, when it was restricted to the posterior pole RPE. By 20 weeks gestation, MFRP expression had spread laterally, and was found throughout the RPE. MFRP protein was detected in both posterior and lateral RPE of the adult eye. CONCLUSIONS Embryonic function of the MFRP gene appears necessary for the eye to reach its full size at birth. Its onset of expression in the RPE during mid-gestation suggests that MFRP does not participate in early formation of the optic cup, and is consistent with a role in later growth and development of the eye. Patients without MFRP gene function exhibit no correction of refractive error during childhood, which suggests that this gene is essential for emmetropization, a complex process by which vision regulates axial growth of the eye.
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Affiliation(s)
- Olof H Sundin
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-92889, USA.
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Blei F. Literature watch. Dellinger, MT, RJ Hunter, et al. (2007). Chy-3 mice are Vegfc haploinsufficient and exhibit defective dermal superficial to deep lymphatic transition and dermal lymphatic hypoplasia. Dev Dyn 236:2346-2355. Lymphat Res Biol 2007; 5:203-4. [PMID: 18035938 DOI: 10.1089/lrb.2007.5308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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