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Marine Chondroitin Sulfate and Its Potential Applications
Published in Se-Kwon Kim, Marine Biochemistry, 2023
A porous collagen/glycosaminoglycan-based scaffold seeded with stromal keratocytes and then epithelial and endothelial cells was used to imitate the corneal extracellular matrix. The collagen-chondroitin sulfate scaffold is an excellent substrate for the creation of artificial corneas due to its capacity to sustain long-term culture, lifespan and handling qualities, which make it appropriate for pharmacotoxicological and drug safety testing. This technology may be developed into a full-thickness man-made cornea by integrating non-transforming human endothelial cells, which is a step toward a substitute for corneal transplantation (Vrana et al., 2008).
Therapeutic Approach in Fungal Keratitis
Published in Mahendra Rai, Marcelo Luís Occhiutto, Mycotic Keratitis, 2019
Victoria Díaz-Tome, María Teresa-Rodríguez Ares, Rubén Varela-Fernández, Rosario Touriño-Peralba, Miguel González-Barcia, Laura Martínez-Pérez, María Jesús Lamas, Francisco J. Otero-Espinar, Anxo Fernández-Ferreiro
Steroids role in the fungal keratitis treatment remains controversial (Nada et al. 2017). Some authors have described that early use of topical steroids for infectious keratitis helps reduce neovascularization, scarring and pain. Activated immune cells release cytokines, collagenases and growth factors, leading to keratocytes apoptosis and collagen destruction. Viable corneal keratocytes are transformed into activated fibroblasts, which restore the tissue defects by irregularly depositing collagen and the extracellular matrix. This causes opacification or haze during the scarring process.
Special Senses
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Kenneth A. Schafer, Oliver C. Turner, Richard A. Altschuler
The corneal endothelium is a single layer of flat, hexagonal, mesenchymal cells joined apically by tight junctions and have a Na/K ATP-dependent pump in the cell membrane to maintain stromal deturgescence (Baroody et al. 1987; Doughty 1994; Joyce 2003). Endothelial cell density is variable among species and within the cornea (less dense in the superior cornea than in the inferior cornea). Endothelial cells decrease in number with age. Humans, nonhuman primates, and cats have little or no regenerative capacity and undergo repair by cell sliding (migration) and individual cell enlargement. Dogs have some regenerative capacity, but repair is still mostly due to cell sliding. The endothelial cells of rabbits can divide and form multinucleated cells. Trauma to the corneal endothelium may allow proliferation of keratocytes with the formation of a fibrous membrane on the inner surface of the cornea (retrocorneal membrane) (Jakobiec and Bhat 2010; Sherrard and Rycroft 1967).
Hyperosmolar Potassium Inhibits Corneal Myofibroblast Transformation and Prevent Corneal Scar
Published in Current Eye Research, 2023
Kai Liao, Zekai Cui, Zhijie Wang, Yu Peng, Shibo Tang, Jiansu Chen
Corneal transparency mainly depends on its organizational structure, which involves a highly ordered arrangement of collagen fibers.1,2 Normally, keratocytes are quiescent in the corneal stroma. However, they can differentiate into corneal fibroblasts (CFs) and myofibroblasts in response to different external stimulation, including trauma, infection, and inflammation.3,4 Previous studies have demonstrated that corneal myofibroblasts play an essential role during the process of corneal fibrosis.5,6 Corneal myofibroblasts can reportedly produce excessive amounts of collagen I, leading to the distortion of tissue architecture.3,7 Consequently, inhibiting corneal myofibroblast transformation to prevent corneal fibrosis has become the focus of many studies.
Effects of 1,25 and 24,25 Vitamin D on Corneal Fibroblast VDR and Vitamin D Metabolizing and Catabolizing Enzymes
Published in Current Eye Research, 2021
Xiaowen Lu, Zhong Chen, Mitchell A. Watsky
Extra-hepatic and extra-renal tissue-specific local production of vitamin D has been demonstrated in a number of tissues.23 Our lab has previously demonstrated that corneal epithelium, which is directly exposed to the sun in the same manner as the skin, has the enzymatic components and ability to generate and activate vitamin D. The vitamin D receptor (VDR), CYP24A1, CYP27B1, and five different vitamin D metabolites have all been detected in the cornea and anterior segment.24,25 To our knowledge, there have been no published studies examining vitamin D metabolism in corneal keratocytes. Quiescent keratocytes constitute the primary cell type of the corneal stroma and occupy approximately 3% of its volume.26 Corneal keratocytes are involved in the synthesis of collagens, proteoglycans, growth factors and related proteins, and are the primary cell type involved in the corneal stroma wound repair process. A number of protein and lipid-associated growth factors have been shown to influence these processes in keratocytes. The presence and activity of the VDR and vitamin D-associated metabolic enzymes have not been studied in corneal keratocytes.
IL-1α Modulates IFN-γ-Induced Production of CXCL9/MIG during Herpes Simplex Virus Type-1 Corneal Infection
Published in Current Eye Research, 2021
S. Armstrong, M. Arroyo, K. Decker-Pulice, M. Lane, M. Mckinney, S. J. Molesworth-Kenyon
In this manuscript, we provide new data which expands on the role of IL-1α during the corneal inflammatory response during HSV-1 infection. We demonstrate that IL-1α can differentially modulate the effect of IFN-γ stimulation of corneal cells and neutrophils, leading to the control over MIG expression. Corneal tissue is demonstrated to require the presence of both IL-1α and IFN-γ to produce maximum levels of MIG. These findings are in line with in vitro studies on human corneal keratocytes.31 However, we observed the greatest modulatory effect by IL-1α to be on neutrophils, with IL-1α demonstrating suppression of IFN-γ-induced MIG production. Production of IP-10, was not regulated by IL-1α in our study, providing further evidence for the differential regulation of the two chemokines.