Research topics

• Retinal degenerative and vascular diseases, including age-related macular degeneration, diabetic retinopathy and retinitis pigmentosa.  
•  Ocular drug delivery, in particular, topical drug delivery for retinal degenerative and angiogenic diseases.  

Research statement

My research has been focused on the role of inflammation in the pathogenesis of retinal degenerative and angiogenic diseases, including age-related macular degeneration (AMD), diabetic retinopathy (DR) and Retinitis Pigmentosa (RP). Although AMD, DR and RP are not classical inflammatory diseases, inflammation is known to play an important role in the initiation and progression of the diseases. We aim to understand how inflammation contributes to the aetiology of these diseases and to identify targets for therapeutic intervention.

Main research activities

1) Inflammation in DR: We are interested in how diabetes affects immune cells and why the immune response to diabetes-mediated retinal injury becomes detrimental in DR. During diabetes, abnormal glucose metabolism can affect the development and function of immune cells (Xu and Chen. Diabetic retinopathy and dysregulated innate immunity. Vision Research. 2017;139:39-46). We have found that prolonged high glucose environment sensitises macrophages to inflammatory stimuli, but reduces the defence function of macrophages (Pavlou, et al. Sustained high glucose exposure sensitizes macrophage responses to cytokine stimuli but reduces their phagocytic activity.BMC Immunology. 2018; Vol. 19:24).  

2) The role of Muller cell in retinal neurovascular unit: The blood-retinal barrier (BRB) is essential for retinal immune privilege. The functional integrity of BRB is maintained by the retinal neurovascular unit. Muller cell, the principal glia spanning almost the entire retina, is an important component of the neurovascular unit. We aim to understand the regulatory role of Muller cells in the neurovascular unit and BRB, and how the regulation is altered in diseases such as DR and AMD. Our group has recently established a mouse Muller cell line (Augustine, et al.  Characterization of a spontaneously immortalized murine Müller glial cell line QMMuC-1. IOVS 2018; Vol. 59, No. 3. pp. 1666-1674), which provides a valuable tool for studying the pathophysiology of Muller cells.    

3) Topical drug delivery for the treatment of retinal diseases: Due to the distinct anatomy of human eyes, it has been very difficult for topically applied drug to reach the posterior segment of the eyes. Teamed with collaborators in University of Birmingham, we have demonstrated that a cell penetrating peptide can aid drugs to the posterior segment of the eyes when applied topically (de Cogan, et al.  Topical Delivery of Anti-VEGF Drugs to the Ocular Posterior Segment Using Cell-Penetrating Peptides. IOVS 2017; Vol. 58, No. 5. pp. 2578-2590).