Research issue
Eye diseases such as diabetic retinopathy and age-related macular degeneration are caused by abnormal leakage from existing blood vessels, and new blood vessel formation in the back of the eye, resulting in damage to areas necessary for clear vision.
However, the way the diseases progress is not fully understood as many factors are involved. Current treatments are not completely successful and are also limited in their ability to reverse the damage caused. Treatments also involve injection of a drug into to eye regularly over a long period of time, increasing the risk of complications and infections.
What we are doing about...
1. Age-Related Macular Degeneration (AMD)
Genes Involved in Variations in Neovascular Disease
The cells which form blood vessels (endothelial cells) can be found all over the body; however, depending on where they are found they can be very different.
We have shown that even in the eye in different tissue layers of the eye, the endothelial cells are very different, as indicated by their different gene expression. This may explain why the neovascular diseases are specific to different locations in the body.
We are continuing to study the different genes expressed to increase our understanding of ocular neovascular diseases and targeting of different treatments to different diseases.
Angiogenic Factors in AMD
An increase in factors which increase blood vessel formation (angiogenic factors) at the back of the eye causes neovascularisation in AMD. The main growth factor involved in angiogenesis is called VEGF.
However, this very complex response depends on many angiogenic factors which is why blocking VEGF alone is not a completely successful treatment.
We are studying the responses of endothelial cells to other factors in order to better understand the process of neovascularisation in the eye and development new and better treatments for the future.
Role of Inflammation in AMD
The damage caused by swelling (inflammation) at the back of the eye is known to be a risk factor in the development of AMD.
We are investigating the role of the innate immune system (toll-like receptors) in the development of AMD and as a possible treatment target for the future.
2. Diabetic Retinopathy
Blood Vessel Leakage in Diabetic Retinopathy
Nearly all people with diabetes will eventually have eye complications due to the disease. The main cause of actual vision loss is diabetic retinopathy is the build up of fluid (Oedema) caused by leakage from increased permeability of existing vessels or the new blood vessels formed.
We are studying the cause of this leakage and the efficacy of current and experimental treatments in to order to develop better future treatments.
3. Other Ocular Neovascular Diseases
Our research can be applied to many other neovascular diseases, particularly in other areas of the eye. In collaboration with other research groups we are also do research into blood vessel formation in wound healing and into corneal neovascularisation.
Low Vision Rehabilitation
At the back of the eye there is an ideal place (macula) for the light to hit in order to create the clearest image. When this area is damaged beyond repair a patient can start naturally using another area to see, although not as clearly, and if training is given, a better area can be used.
We are studying the use of a new piece of equipment in order to get the best possible vision for these patients.
Outcomes
*Saker, S., *Stewart, E.A., Browning, A.C., Allen, C.L., Amoaku, W.M. 2014. The Effect of Hyperglycaemia on Permeability and the Expression of Junctional Complex Molecules in Human Retinal and Choroidal Endothelial Cells. Experimental Eye Research 121, 161-167.
Amoaku, W., S. Blakeney, M. Freeman, R. Gale, R. Johnston, S.P. Kelly, B. McLaughlan, D. Sahu, and D. Varma. 2012. Action on AMD. Optimising patient management: act now to ensure current and continual delivery of best possible patient care. Eye (Lond) 26 Suppl 1:S2-21.
Browning, A.C., E.P. Halligan, E.A. Stewart, D.C. Swan, R. Dove, G.J. Samaranayake, and W.M. Amoaku. 2012. Comparative gene expression profiling of human umbilical vein endothelial cells and ocular vascular endothelial cells. Br J Ophthalmol 96:128-132.
Stewart, E.A., G.J. Samaranayake, A.C. Browning, A. Hopkinson, and W.M. Amoaku. 2011. Comparison of choroidal and retinal endothelial cells: Characteristics and response to VEGF isoforms and anti-VEGF treatments. Experimental Eye Research 93:761-766.
Wei, R., E.A. Stewart, and W.M. Amoaku. 2013. Suitability of endogenous reference genes for gene expression studies with human intraocular endothelial cells. BMC Res Notes 6:46.
Winfried Amoaku is involved in many multi-centre clinical trials for the treatment of age-related macular degeneration, diabetic macular oedema and retinal vein occlusion.
The ocular neovascularisation group is partially supported by research grants from Novartis and Allergan.
Links
- Royal National Institute of Blind People - Age-related Macular Degeneration (AMD)
- Diabetes UK - Your eyes and diabetes