November 10, 2005 Source: University of Calgary:
http://www.ucalgary.ca/news/nov05/retina-release.html Scientists uncover how retina responds to genetic damage Findings open up new avenues of investigation
into vision conditions and disease Torben Bech-Hansen, PhD, the Roy and Joan Allen Professor in Sight Research, Faculty of Medicine, University of Calgary, and colleagues at U of C and Dalhousie University, have published a study in Human Molecular Genetics that pinpoints the specific place in the retina where vision problems begin. "In this study, we use genetics to investigate how the synapses in the eye help nerve cells to communicate," says Bech-Hansen. "Damage to the retina looks the same under the microscope, whether it is the result of physical trauma – a detached retina – or a specific genetic mutation. Our hope is that these findings will lead to the exploration of treatments for vision problems such as near-sightedness, and night blindness." When the research team "turned off" the mouse gene known to cause night blindness in humans, scientists found that synapses between specific nerve cells were lost so that they could no longer communicate with each other. "People with night blindness have an altered ERG – electroretinogram – and so do the mice that we studied," says Bech-Hansen. "This finding should help us to translate what we found in the laboratory into the clinic." The study finds that a calcium channel protein plays a key role in how nerve cells function, presenting an opportunity to study how the retina responds to genetic and physical injuries. "The calcium channels are flags that we can follow, and are likely to lead us beyond the retina into other parts of the nervous system affected by human disease," says Bech-Hansen. "This is the first research to demonstrate that a structural defect exists between photoreceptors and other neurons in the mutated retina. These abnormal connections are undoubtedly the root cause of the loss of transmission of the signal to the other neurons in the retina, the optic nerve, and the visual cortex," says Dr. Richard Weleber, professor of ophthalmology, and molecular and medical genetics, Casey Eye Institute, Oregon Health & Science University. "This gives us a new vantage point from which to study the function of the retina – something that could lead to new treatment strategies for our patients." This research was supported by the Canadian Foundation Fighting Blindness, the Canadian Institutes of Health Research, the I.D. Bebensee Foundation, the Lions’ Sight Centre in U of C’s Faculty of Medicine, and the Alberta Children’s Hospital Foundation. For more information: Torben Bech-Hansen, PhD, 403.220.8387, ntbech@ucalgary.ca __________ Karen Thomas,
Director, Media Relations
403.220.2431
| 