Ocular Tissue Engineering
Doctor Fred Chen is a Senior Lecturer at the University of Western Australia and he established the Ocular Tissue Engineering Laboratory at Lion Eye Institute in 2010. Fred has gained international recognition in the field of retinal clinical trials endpoint analysis, retinal pigment epithelium (RPE) transplantation and stem cells. Through his doctoral thesis (http://discovery.ucl.ac.uk/1318070/), “RPE transplantation in retinal diseases”, he has developed and validated new methods of analyzing functional and anatomical outcomes of clinical retinal cell therapy. This work has led to the first phase I trial of RPE sheet transplantation in the UK.
His group is currently exploring autologous cell sources for retinal preservation and regeneration, and new methods of deriving induced pluripotent stem cells for retinal differentiation. In parallel with his stem cell work, Fred’s group also conducts clinical research to validate new diagnostic retinal imaging tools and develop software to measure disease progression in macular degeneration and retinal dystrophy. He is a principle investigator for several observational studies in visual acuity and microperimetry reliability, long-term outcomes of anti-VEGF therapy, blindness rate in Western Australia, early detection of toxic retinopathy and phenotype-genotype correlations in macular degenerations and inherited retinal diseases http://irdregister.org.au/). He is also the lead investigator for novel laser and new drug treatments for drusen, geographic atrophy and neovascular macular degeneration.
His collaborators include Murdoch University, Edith Cowan University, Curtin University, Ear Science Institute Australia, Queensland Eye Institute, Queensland University of Technology, Flinders University, Save Sight Institute, University of Sydney, Centre for Eye Research Australia, University of Melbourne, Moorfields Eye Hospital and University College of London.
- Dedifferentiation of human limbal stem cells to pluripotency
The human corneoscleral limbus contains multipotent stem cells that can be isolated and cultured for clinical applications, such as the treatment of limbal stem cell deficiency. Studies in rodents have shown that stem cells in the limbus can be induced to form floating neurospheres in the presence of the BMP receptor antagonist Noggin and that these neurospheres can be further dedifferentiated to pluripotency using conditioned media. Limbal neurospheres (LiNS) express three (SOX2, KLF4 and C-MYC) of the four transcription factors identified as being sufficient for reprogramming cells to pluripotency, lacking only Oct4, the master pluripotency gene. The induction of Oct-4 expression in rodent LiNS by microenvironmental signals suggests close similarities between the LiNS transcriptome and that of pluripotent stem cells. Although results from our lab and others have described the induction of LiNS from human limbal tissue, the induction of pluripotency from primary human LiNS has not yet been reported. Our project aims to examine the effects of microenvironmental factors on pluripotent gene expression in human LiNS.
- Production of Retinal Pigment Epithelium by Cellular Reprogramming
Since the development of the induced-pluripotent-stem (iPS) stem cell reprogramming technique by Yamanaka in 2006, the field of cellular reprogramming has progressed rapidly and the principle of using exogenous transcription factors to control cell fate has been widely studied in the context of inducing pluripotency. Recent developments, such as the replacement of retroviral transgene delivery with the use of synthetic mRNA to achieve reprogramming factor expression, have begun to address the technical obstacles that remain between the new method and its implementation in a clinical setting. The primary aim of this project is the production of retinal pigment epithelium (RPE) using exogenous transcription factors delivered as synthetic mRNA. RPE dysfunction is a major contributor to retinal disease, including age-related macular disease, and transplantation of healthy RPE has been shown to improve visual function in human patients. RPE patches are currently being developed using human embryonic stem (hES) cell cultures, however, immunological and ethical concerns limit the suitability of these cells for clinical application. To address these concerns, this project aims to evaluate a number of donor cell populations for reprogramming potential, including umbilical cord blood, towards the end of identifying the most suitable cells for tissue engineering applications.
- Western Australia Retinal Degeneration study
This is a prospective cohort study of patients with inherited retinal disease and various forms of macular degeneration (age-related, myopic, inflammatory, vascular etc.). Patients donate blood and skin tissue sample for detection of autoantibodies and stem cell disease modelling. Six monthly reviews with multimodal retinal imaging provide invaluable clinical information on disease progression rate. Optical coherence tomography, fundus autofluorescence, widefield photography, AO imaging and microperimetry are performed at each clinic visit. Undergraduate and postgraduate students and junior doctors can contribute to this project through patient recruitment, retinal imaging and image analysis to measure disease progression rates. Numerous genetically characterised fibroblast cell lines are available for Honours, Masters and PhD program in disease modelling and drug therapy development. There are also opportunities for exploring genotype-phenotype correlations of rare inherited retinal diseases. The Miocevich Retina Fellow is closely involved in the coordination of this cohort study.
- High resolution retinal cell imaging
We are exploring the clinical utility of high resolution cone photoreceptor imaging device: rtx AO camera. Through this device, individual cone cells can be visualised and counted throughout the macular region (central 20° × 20° area of the retina). Each image frame covers 4° × 4° area of the retina. We have a large AO image library of healthy controls and patients with retinal diseases (colour vision deficit, laser injury, drug toxicity, inflammatory eye disease, inherited retinal disease and macular degeneration). Undergraduate and postgraduate students and junior doctors can be involved in developing new methods of images processing and analysis. Variables such as cone density and Nyquist frequency are measured at retinal loci determined by cartesian and polar coordinate systems.
- Optical coherence tomography and angiography
Blood vessels imaging typically requires a contrast dye. A new technology in optical coherence tomography (OCT) now enables blood vessels to be visualised without the use of chemical dye injected into the vein. This technique, OCT angiography (OCTA), is now available commercially and is used in routine clinics. Lions Eye Institute had the first OCTA device in Australia and is leading research in this area. We are interested in validation of images acquired through OCTA and its use as clinical trials endpoint for diseases such as diabetic retinopathy and macular degeneration. Undergraduate and postgraduate students and junior doctors can be involved in collecting patient images and data analysis. Our goal is to develop faster OCTA device and more accurate image analysis software to minimise motion and segmentation artefacts, which are major limitations in the current commercial systems.
- Microperimetry for measuring disease progression
The most commonly used method to measure vision is visual acuity. However, this technique only measures the function of central point (fovea) of the central portion of the retina (macula). Patients with diseases that spare the fovea will not show impairment of visual acuity until late in the disease process. Therefore a better method of monitoring the central region of the retina is required for many types of macular diseases. Microperimetry combines a fundus tracking camera with visual field test. Lions Eye Institute is the first clinic in Australia to be using microperimetry and the only clinic with 4 microperimeters. We have a large library of microperimetry data from healthy subjects and patients with various eye diseases (including inherited retinal disease, macular degeneration, ocular injury, drug toxicity, inflammatory eye disease, myopic degeneration and glaucoma). Undergraduate and postgraduate students and junior doctors can be involved in performing microperimetry examinations and data analysis of longitudinal changes in microperimetry measurements.
- Anti-retinal antibody biomarkers in degenerative retinal diseases
Auto-antibodies against retinal protein are commonly found in patients with retinal diseases. There is much uncertainty in the interpretation of results of anti-retinal autoantibody (ARA) tests due to overlaps in clinical syndromes and antibody profiles across different disease processes. Our projects aims to characterise ARAs in healthy controls and patients with macular degeneration, genetically characterised inherited retinal diseases and autoimmune retinopathy. Autoantigens will be identified using protein microarrays and ARA profile will be correlated with genotype, phenotype and disease progression.