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Barhaiya RK, Kumar P. Histology, histochemistry and ultrastructure of cornea of domestic pigs (Sus scrofa domesticus). Anat Histol Embryol 2024; 53:e13068. [PMID: 38837763 DOI: 10.1111/ahe.13068] [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: 10/10/2023] [Revised: 05/21/2024] [Accepted: 05/27/2024] [Indexed: 06/07/2024]
Abstract
A comprehensive light and ultrastructural examination of the cornea in Domestic Pigs (Sus scrofa domesticus) revealed four distinct layers: the anterior epithelium, corneal stroma, Descemet's membrane and endothelium. Although Bowman's layer was not distinctly identified through histology, histochemical analysis indicated the presence of a rudimentary Bowman's layer, possibly vestigial from evolution. Scanning electron microscopy of the outer corneal surface unveiled two cell types, characterized by micro-projections, with light cells exhibiting shorter, thicker projections compared to dark cells. Examination of the inner surface via scanning electron microscopy demonstrated an endothelial layer devoid of cilia and microvilli, yet faint round to oval elevations were observed, potentially representing cell nuclei. Transmission electron microscopy unveiled that basal cells of the anterior epithelium closely adhered to the basement membrane, featuring half desmosomes along the basal surface. These basal cells extensively interconnected through interdigitations and a few desmosomes. The superficial cell layer consisted of a few rows of closely attached flat cells, forming a leak-proof layer with zona occludens. The outermost cells of this layer displayed fine projections to enhance the surface area, facilitating tear film distribution. At lower magnification, Transmission electron microscopy of the corneal stroma revealed alternating light and dark bands, with light bands representing transverse sections of collagen fibril lamellae and dark bands corresponding to longitudinal or oblique sections. Spindle-shaped keratocytes (fibroblasts) were identified as the primary stromal cells, intermingled between the lamellae, and featured long processes in close contact with neighbouring keratocytes. Overall, the histomorphology of the pig cornea resembles that of the human cornea except indistinct Bowman's membrane. This detailed understanding of the normal corneal structure in pigs hold great significance for biomedical research, providing a valuable reference for studies involving this animal model.
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Affiliation(s)
- Rakesh Kumar Barhaiya
- Department of Veterinary Anatomy, College of Veterinary Science and Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur, India
| | - Pawan Kumar
- Department of Veterinary Anatomy, College of Veterinary Science, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, India
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McCall MA. Pig Models in Retinal Research and Retinal Disease. Cold Spring Harb Perspect Med 2024; 14:a041296. [PMID: 37553210 PMCID: PMC10982707 DOI: 10.1101/cshperspect.a041296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
The pig has been used as a large animal model in biomedical research for many years and its use continues to increase because induced mutations phenocopy several inherited human diseases. In addition, they are continuous breeders, can be propagated by artificial insemination, have large litter sizes (on the order of mice), and can be genetically manipulated using all of the techniques that are currently available in mice. The pioneering work of Petters and colleagues set the stage for the use of the pig as a model of inherited retinal disease. In the last 10 years, the pig has become a model of choice where specific disease-causing mutations that are not phenocopied in rodents need to be studied and therapeutic approaches explored. The pig is not only used for retinal eye disease but also for the study of the cornea and lens. This review attempts to show how broad the use of the pig has become and how it has contributed to the assessment of treatments for eye disease. In the last 10 years, there have been several reviews that included the use of the pig in biomedical research (see body of the review) that included information about retinal disease. None directly discuss the use of the pig as an animal model for retinal diseases, including inherited diseases, where a single genetic mutation has been identified or for multifactorial diseases such as glaucoma and diabetic retinopathy. Although the pig is used to explore diseases of the cornea and lens, this review focuses on how and why the pig, as a large animal model, is useful for research in neural retinal disease and its treatment.
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Affiliation(s)
- Maureen A McCall
- Departments of Ophthalmology & Visual Sciences and Anatomical Sciences & Neurobiology, University of Louisville, Louisville, Kentucky 40202, USA
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Wang X, Shakeel A, Salih AE, Vurivi H, Daoud S, Desidery L, Khan RL, Shibru MG, Ali ZM, Butt H, Chan V, Corridon PR. A scalable corneal xenograft platform: simultaneous opportunities for tissue engineering and circular economic sustainability by repurposing slaughterhouse waste. Front Bioeng Biotechnol 2023; 11:1133122. [PMID: 37180037 PMCID: PMC10168539 DOI: 10.3389/fbioe.2023.1133122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 04/17/2023] [Indexed: 05/15/2023] Open
Abstract
Introduction: Corneal disease is a leading cause of blindness globally that stems from various etiologies. High-throughput platforms that can generate substantial quantities of corneal grafts will be invaluable in addressing the existing global demand for keratoplasty. Slaughterhouses generate substantial quantities of underutilized biological waste that can be repurposed to reduce current environmentally unfriendly practices. Such efforts to support sustainability can simultaneously drive the development of bioartificial keratoprostheses. Methods: Scores of discarded eyes from the prominent Arabian sheep breeds in our surrounding region of the United Arab Emirates (UAE) were repurposed to generate native and acellular corneal keratoprostheses. Acellular corneal scaffolds were created using a whole-eye immersion/agitation-based decellularization technique with a widely available, eco-friendly, and inexpensive 4% zwitterionic biosurfactant solution (Ecover, Malle, Belgium). Conventional approaches like DNA quantification, ECM fibril organization, scaffold dimensions, ocular transparency and transmittance, surface tension measurements, and Fourier-transform infrared (FTIR) spectroscopy were used to examine corneal scaffold composition. Results: Using this high-throughput system, we effectively removed over 95% of the native DNA from native corneas while retaining the innate microarchitecture that supported substantial light transmission (over 70%) after reversing opacity, a well-established hallmark of decellularization and long-term native corneal storage, with glycerol. FTIR data revealed the absence of spectral peaks in the frequency range 2849 cm-1 to 3075 cm-1, indicating the effective removal of the residual biosurfactant post-decellularization. Surface tension studies confirmed the FTIR data by capturing the surfactant's progressive and effectual removal through tension measurements ranging from approximately 35 mN/m for the 4% decellularizing agent to 70 mN/m for elutes highlighting the effective removal of the detergent. Discussion: To our knowledge, this is the first dataset to be generated outlining a platform that can produce dozens of ovine acellular corneal scaffolds that effectively preserve ocular transparency, transmittance, and ECM components using an eco-friendly surfactant. Analogously, decellularization technologies can support corneal regeneration with attributes comparable to native xenografts. Thus, this study presents a simplified, inexpensive, and scalable high-throughput corneal xenograft platform to support tissue engineering, regenerative medicine, and circular economic sustainability.
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Affiliation(s)
- Xinyu Wang
- Biomedical Engineering and Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi, United Arab Emirates
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Adeeba Shakeel
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Ahmed E. Salih
- Department of Mechanical Engineering, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Hema Vurivi
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Sayel Daoud
- Anatomical Pathology Laboratory, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Luca Desidery
- Department of Civil Infrastructure and Environmental Engineering, College of Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Raheema L. Khan
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Meklit G. Shibru
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Zehara M. Ali
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Haider Butt
- Department of Mechanical Engineering, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Vincent Chan
- Biomedical Engineering and Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Peter R. Corridon
- Biomedical Engineering and Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi, United Arab Emirates
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
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Dan Cosnita AR, Raica M, Sava MP, Cimpean AM. Gene Expression Profile of Vascular Endothelial Growth Factors (VEGFs) and Platelet-derived Growth Factors (PDGFs) in the Normal Cornea. In Vivo 2021; 35:805-813. [PMID: 33622873 DOI: 10.21873/invivo.12321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 11/26/2020] [Accepted: 12/03/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM Angiogenic growth factors expression is not known in the normal cornea. The aim was to study corneal gene expression profile of VEGF and PDGF pathways influencing the avascular state of cornea. MATERIALS AND METHODS cDNA synthesis was performed from mRNA extracted from five fresh pig corneas followed by cDNA synthesis and analysis of VEGF and PDGF pathways by TaqMan Array gene expression profile. RESULTS Normal pig cornea lacks VEGFR2 and VEGFR3 gene expression. MK2 and AKT1 genes were significantly overexpressed (p=0.000684, p=0.050995, respectively). Six PDGF pathway genes were overexpressed: TIAM1 (p=0.047), PIK3CA (p=0.00005), IKBKG (p=0.000006), PAK4 (p=0.034), RAC1 (p=0.000006 and PTGS2, p=0.00375). PDGF A was up-regulated, but not with a statistical significance (p=0.79911), while PDGFRα was down-regulated and PDGFRβ was not expressed. CONCLUSION Normal cornea avascularity is given by growth factor receptors down-regulation. Rapid corneal neovascularisation is induced by activation of the main angiogenic growth factors that induce angiogenic cascade and vessel recruitment.
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Affiliation(s)
- Andrei Radu Dan Cosnita
- Department IX, Surgery I/Ophthalmology, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania
| | - Marius Raica
- Department of Microscopic Morphology/Histology, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania.,Angiogenesis Research Center, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania
| | - Mihai Poenaru Sava
- Department IX, Surgery I/Ophthalmology, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania
| | - Anca Maria Cimpean
- Department of Microscopic Morphology/Histology, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania; .,Angiogenesis Research Center, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania
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Isidan A, Liu S, Li P, Lashmet M, Smith LJ, Hara H, Cooper DKC, Ekser B. Decellularization methods for developing porcine corneal xenografts and future perspectives. Xenotransplantation 2019; 26:e12564. [PMID: 31659811 DOI: 10.1111/xen.12564] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/11/2019] [Accepted: 10/13/2019] [Indexed: 12/23/2022]
Abstract
Corneal transplantation is the only option to cure corneal opacities. However, there is an imbalance between supply and demand of corneal tissues in the world. To solve the problem of corneal shortage, corneal xenotransplantation studies have been implemented in the past years using porcine corneas. The corneal xenografts could come from (a) wild-type pigs, (b) genetically engineered pigs, (c) decellularized porcine corneas, and (d) decellularized porcine corneas that are recellularized with human corneal cells, eventually with patients' own cells, as in all type of xenografts. All approaches except, the former would reduce or mitigate recipient immune responses. Although several techniques in decellularization have been reported, there is still no standardized protocol for the complete decellularization of corneal tissue. Herein, we reviewed different decellularization methods for porcine corneas based on the mechanism of action, decellularization efficacy, biocompatibility, and the undesirable effects on corneal ultrastructure. We compared 9 decellularization methods including: (a) sodium dodecyl sulfate, (b) triton x-100, (c) hypertonic saline, (d) human serum with electrophoresis, (e) high hydrostatic pressure, (f) freeze-thaw, (h) nitrogen gas, (h) phospholipase A2 , and (i) glycerol with chemical crosslinking methods. It appears that combined methods could be more useful to perform efficient corneal decellularization.
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Affiliation(s)
- Abdulkadir Isidan
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Shaohui Liu
- Department of Ophthalmology, Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ping Li
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Matthew Lashmet
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Lester J Smith
- Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.,3D Bioprinting Core, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Burcin Ekser
- Transplant Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
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