Jennifer Jane McGhee
University of Auckland
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Featured researches published by Jennifer Jane McGhee.
Investigative Ophthalmology & Visual Science | 2012
Christina N Grupcheva; Wilda Laux; Ilva D. Rupenthal; Jennifer Jane McGhee; Charles Nj McGhee; Colin R. Green
PURPOSE Gap junctions play a major role in corneal wound healing. This study used reproducible models of corneal wound healing to evaluate the effect of a gap junction channel modulator, connexin43 (Cx43) antisense oligodeoxynucleotides (AsODN), on corneal healing dynamics. METHODS A mechanical scrape wound model was used to evaluate Cx43 AsODN penetration and initial wound reepithelialization 12 hours postsurgery. Thereafter, detailed analyses of corneal edema, inflammation, and healing were performed in an excimer laser surface ablation model. In vivo confocal microscopy determined clinical parameters (edema, haze) and cellular changes (stromal hypercellularity, reepithelialization), whereas histology and immunohistochemistry were used to quantify stromal edema, inflammation, and reepithelialization. RESULTS Cx43 AsODN penetrated through the hydrophilic stroma where the epithelium had been removed and accumulated in the basal epithelium close to the wound edge. Twelve hours after scrape wounding, Cx43 AsODN-treated eyes showed a significant reduction in wound area compared with the vehicle alone (1.59±0.37 and 2.29±0.58 mm2, respectively, P<0.01). After excimer laser ablation, stromal edema and inflammation were reduced, with endothelial structures being clearly visible, and reepithelialization rates were again increased in Cx43 AsODN-treated eyes. Histologic analysis confirmed reduced edema in the central wound site and at the periphery of treated corneas (P<0.05), whereas immunohistochemistry showed lower Cx43 levels (P<0.05), reduced myofibroblast activation, and improved epithelial basal lamina deposition in antisense-treated wounds (P<0.01). CONCLUSIONS Application of Cx43 AsODN to the cornea reduces stromal edema and inflammation, promoting faster wound closure and a more uniform repair of the epithelial basal lamina after laser ablation.
Cornea | 2011
Chuan-Yuan Ally Chang; Jennifer Jane McGhee; Colin R. Green; Trevor Sherwin
Purpose: The limbus of the cornea is said to be the niche for limbal stem cells (LSCs) and the primary source of corneal epithelial maintenance. Previously, we aimed to have shown that central human epithelial cells are capable of corneal regeneration after wounding. In this study, we aimed to investigate whether central epithelial cells in human corneas have LSC properties. Methods: Human corneal epithelial cells were separated from the central cornea and the limbus. Isolated cells were collected for sphere-forming assay, and spheres formed subsequently were analyzed using immunohistochemistry. Fluorescence-activated cell sorting (FACS) was also used to analyze epithelial cells from central cornea, limbal rim, older donors, younger donors, and dissociated spheres. These analyses were based on cell size and Hoechst 33342 dye efflux ability, and side populations and non-side populations were isolated for colony growth measurement and sphere-forming assay. Results: Human central and limbal epithelial cells were capable of forming spheres, in a 1:2 ratio, that were positive for p63 immunolabeling. In FACS, central and limbal epithelial cells showed no significant difference in cell size and dye efflux ability. There were almost 10 times more large cells with good dye efflux ability from younger donors than from older donors, and the gated side population showed more than 4 times faster rate of colony growth than the non-side population. Dissociated sphere cells, however, did not follow a similar pattern to tissue-derived cells using FACS analysis. In these, there were more than twice as many large cells than small cells with good dye efflux ability. Conclusions: Both limbal and central epithelial cells are capable of forming spheres in cultures that have stem cell properties. Central and limbal epithelial cells cannot be differentiated using FACS, but younger donor tissues give rise to greater numbers of large cells with high dye efflux. Therefore, results indicate that human central corneal epithelium contains cells with stem/progenitor properties, and these stem properties decline with age.
Journal of Cataract and Refractive Surgery | 2002
Nisha Sachdev; Charles Nj McGhee; Jennifer P. Craig; Kathryn H. Weed; Jennifer Jane McGhee
This case reports an association between 2 uncommon flap complications in 1 eye related to epithelial toxicity and subsequent epithelial defect secondary to prolonged intraoperative exposure to topical anesthesia. A patient had hyperopic laser in situ keratomileusis (LASIK) for the correction of +2.75 +1.75 x 70 in the left eye. Because of the patients anxiety and movement, additional topical local anesthesia was used and the flap remained reflected for 5 minutes. Immediately postsurgery, a toxic appearance was noted in the epithelium of the LASIK flap; 24 hours later, a large central epithelial defect was identified. Three days post- LASIK, the epithelial defect had healed but diffuse lamellar keratitis was noted in the interface, particularly underlying the location of the original epithelial defect. Over 6 weeks, a self-limiting epithelial ingrowth developed in the inferior interface. Fourteen months post-LASIK, the uncorrected visual acuity was 6/9 with a residual refraction of +0.50 +0.50 x 90.
Clinical and Experimental Ophthalmology | 2012
Damien G. Harkin; Andrew Apel; Nick Di Girolamo; Stephanie Watson; Karl David Brown; Mark Daniell; Jennifer Jane McGhee; Charles Nj McGhee
Cultured limbal tissue transplants have become widely used over the last decade as a treatment for limbal stem cell deficiency (LSCD). While the number of patients afflicted with LSCD in Australia and New Zealand is considered to be relatively low, the impact of this disease on quality of life is so severe that the potential efficacy of cultured transplants has necessitated investigation. We presently review the basic biology and experimental strategies associated with the use of cultured limbal tissue transplants in Australia and New Zealand. In doing so, we aim to encourage informed discussion on the issues required to advance the use of cultured limbal transplants in Australia and New Zealand. Moreover, we propose that a collaborative network could be established to maintain access to the technology in conjunction with a number of other existing and emerging treatments for eye diseases.
Clinical and Experimental Ophthalmology | 2011
Simon Dean; Alex Petty; Simon Swift; Jennifer Jane McGhee; Anant Sharma; Sunil Shah; Jennifer P. Craig
Background: A prototype solid‐state Ultraviolet‐C (UVC) LED device may be useful in the treatment of corneal microbial infections, as UVC is commonly used for eradicating bacteria, fungi and viruses in other settings. This study assessed the efficacy of 265 nm UVC from this LED, on four different bacterial strains, and investigated the consequences of corresponding exposures on human corneal epithelial cells in vitro.
Cell Biology International | 2013
Jinny J. Yoon; Ellen F. Wang; Salim Ismail; Jennifer Jane McGhee; Trevor Sherwin
Sphere‐forming cells from peripheral cornea represent a potential source of progenitor cells for treatment of corneal degenerative diseases. Control of cellular repopulation on transplantable substrates is important to prevent uncontrolled growth in unfavourable directions. The coordination of cellular outgrowth may be in response to environmental cues and/or cellular signals from other spheres. To investigate this, cell migration patterns were observed following placement of spheres on an adhesive surface. Human peripheral corneal cells were maintained using a sphere‐forming assay and their behaviour on collagen substrate recorded by time‐lapse imaging. Immunocytochemistry and proliferation assays were used to detect protein expression and cell division. Proliferation assays showed that spheres formed by a combination of cell division and aggregation. Cell division continued within spheres for up to 4 months and was up‐regulated when exposed to differentiation medium and collagen substrate. The spheres expressed both epithelial and stromal cell markers. When exposed to collagen; (1) 25% of the spheres showed spontaneous polarised outgrowth. (2) One sphere initially showed polarised outgrowth followed by collective migration with discrete morphological changes to form leading and trailing compartments. (3) A sphere which did not show polarised outgrowth was also capable of collective migration using cell protrusion and retraction. (4) Active recruitment of cells into spheres was observed. (5) Placement of spheres in close proximity led to production of a cell exclusion area adjacent to spheres. Thus peripheral corneal cell spheres are dynamic entities capable of developing polarity and modifying migration in response to their environment.
Stem Cell Research & Therapy | 2016
Jeremy John Mathan; Salim Ismail; Jennifer Jane McGhee; Charles N.J. McGhee; Trevor Sherwin
BackgroundThe limbus forms the outer rim of the cornea at the corneoscleral junction and harbours a population of stem cells for corneal maintenance. Injuries to the limbus, through disease or accidents such as chemical injuries or burns, may lead to significant visual impairment due to depletion of the native stem cells of the tissue.MethodsSphere-forming cells were isolated from peripheral cornea for potential use as transplantable elements for limbal stem cell repopulation and limbal reconstruction. Immunocytochemistry, live cell imaging and quantitative PCR were used to characterize spheres and elucidate activity post implantation into human cadaveric corneal tissue.ResultsSpheres stained positively for stem cell markers ∆NP63α, ABCG2 and ABCB5 as well as the basal limbal marker and putative niche marker, notch 1. In addition, spheres also stained positively for markers of corneal cells, vimentin, keratin 3, keratocan and laminin, indicating a heterogeneous mix of stromal and epithelial-origin cells. Upon implantation into decellularized corneoscleral tissue, 3D, polarized and radially orientated cell migration with cell proliferation was observed. Cells migrated out from the spheres and repopulated the entire corneal surface over 14 days. Post-implantation analysis revealed qualitative evidence of stem, stromal and epithelial cell markers while quantitative PCR showed a quantitative reduction in keratocan and laminin expression indicative of an enhanced progenitor cell response. Proliferation, quantified by PCNA expression, significantly increased at 4 days subsequently followed by a decrease at day 7 post implantation.ConclusionThese observations suggest great promise for the potential of peripheral corneal spheres as transplantable units for corneal repair, targeting ocular surface regeneration and stem cell repopulation.
Experimental Cell Research | 2014
Carol Ann Greene; C.-Y. Chang; Cameron J. Fraser; Dasha Nelidova; Jing A. Chen; Angela Lim; Alex Brebner; Jennifer Jane McGhee; Trevor Sherwin; Colin R. Green
Cells thought to be stem cells isolated from the cornea of the eye have been shown to exhibit neurogenic potential. We set out to uncover the identity and location of these cells within the cornea and to elucidate their neuronal protein and gene expression profile during the process of switching to a neuron-like cell. Here we report that every cell of the adult human and rat corneal stroma is capable of differentiating into a neuron-like cell when treated with neurogenic differentiation specifying growth factors. Furthermore, the expression of genes regulating neurogenesis and mature neuronal structure and function was increased. The switch from a corneal stromal cell to a neuron-like cell was also shown to occur in vivo in intact corneas of living rats. Our results clearly indicate that lineage specifying growth factors can affect changes in the protein and gene expression profiles of adult cells, suggesting that possibly many adult cell populations can be made to switch into another type of mature cell by simply modifying the growth factor environment.
Cell Biology International | 2015
Stephanie U. Huang; Jinny J. Yoon; Salim Ismail; Jennifer Jane McGhee; Trevor Sherwin
The cornea is the initial refractive interface of the eye. Its transparency is critical for clear vision and is maintained by stem cells which also act to repair injury inflicted by external insults, such as chemical and thermal burns. Damage to the epithelium compromises its clarity and can reduce or eliminate the stem cell population, diminishing the ability for self‐repair. This condition has been termed “limbal stem cell deficiency”; severe cases can lead to corneal blindness. Sphere‐forming cells isolated from peripheral cornea are a potential source of stem and progenitor cells for corneal repair. When provided with appropriate substrate, these spheres have the ability to adhere and for cells to migrate outwards akin to that of their natural environment. Direct compression injury and remote scratch injury experiments were conducted on the sphere cells to gauge their wound healing capacity. Measures of proliferation, differentiation, and migration were assessed by immunohistochemical detection of EdU incorporation, α‐smooth muscle actin expression and confocal image analysis, respectively. Both modes of injury were observed to draw responses from the spheres indicating wound healing processes. Direct wounding induced a rapid, but transient increase in expression of α‐SMA, a marker of corneal myofibroblasts, followed by a proliferative and increasing migratory response. The spheres were observed to respond to remote injury as entire units, with no directional response seen for targeted repair over the scratch injury area. These results give strength to the future use of these peripheral corneal spheres as transplantable units for the regeneration of corneal tissue.
Archive | 2017
Trevor Sherwin; Salim Ismail; I-Ping Loh; Jennifer Jane McGhee
Histopathology has long been used to confirm the diagnosis of keratoconus and to determine the extent of disease progression in tissue post-corneal transplant. We examine here how modern advances in histopathology have informed the pathology of the condition and describe how the technique of immunohistochemistry, in particular, has enabled researchers to describe pathology down to the protein and molecular level. This chapter examines how this information has been used to decipher clues towards understanding the pathogenesis of keratoconus.