Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Potential drug therapy for diabetic retinopathy under study

09.11.2010
One drug's startling ability to restore retinal health in the eyes of diabetic mice has researchers wanting to learn more about how it works and whether it might do the same for people.

"We want to know if this drug has the potential to block the visual devastation that can occur with diabetes," said Dr. Sylvia Smith, retinal cell biologist and co-director of the Vision Discovery Institute at the Medical College of Georgia. "That means we need to know more about how and when it is effective."

Diabetic retinopathy, the leading cause of blindness in working-age Americans, results from the destruction of the retina, a thin layer at the back of the eyeball that converts lights to signals that the brain can interpret as images. The retina, which deals with daily assaults from the sun and other external forces, is slowly injured by the high glucose levels of diabetes then further injured when it grows more blood vessels in an attempt to get more blood and oxygen to dying cells.

At least in the early stage of diabetes in mice, MCG researchers appear to have interrupted the first wave of cell destruction with the drug (+)- pentazocine – known for its pain-relieving power – by reducing cell stress. A new $1.5 million grant from the National Eye Institute will enable scientists to test their cell stress theory and fill in missing pieces about how and when the drug works.

Smith and her colleagues have evidence that oxidative stress, believed to be a key player in the cell damage resulting from diabetes, increases the binding of sigma receptors to BiP, a stress protein. Sigma receptors are believed to help cells cope with stress.

While some results of the union are unclear, it is clear that in the mice, (+)- pentazocine reduces binding between the two to a more usual, non-stressed level and restores the typically well-stratified retina to a more healthy state. Smith termed the result "phenomenal" when it was published in Investigative Ophthalmology & Visual Science in 2008. In fact, subsequent research has shown, (+)- pentazocine improves the look of the multi-layer retina in a healthy mouse.

"We know (+)- pentazocine binds to sigma receptors, but one of the things we don't know is if the binding blocks or promotes sigma receptor action," Smith said. Working with Dr. Eric Zorilla at The Scripps Research Institute in California, Smith now has mice with sigma receptors deleted that will help her better determine their role and how (+)- pentazocine intervenes.

Dr. Alan Saul, MCG electrophysiologist skilled in measuring the response of the retina to light, is helping her objectively measure the impact on mouse vision. Much like an EEG measures the electrical activity of the brain, Saul, a faculty member in the MCG Department of Ophthalmology, helps measure the electrical response of the retina – which is part of the brain – to light as an objective vision test to accompany the more common vision chart.

Without a mouse vision chart, it's hard to be certain that a better-looking retina translates to better vision, Smith said. In fact, Saul has seen it go both ways in patients: an eye exam indicates good vision while the retinal test shows differently, and vice versa. "You are surprised a lot of the time," Saul said. In fact, they are beginning to find some surprises in mice with a related problem. Diabetes essentially doubles the glaucoma risk and as their mice with glaucoma reach the equivalent of their 20s and 30s in human years. Saul's electrical exams show early changes in their optic nerves – which extend from the retina to the brain – even though they look normal on microscopic exam.

To help fill in the knowledge gaps, the scientists are inducing diabetes in the mice missing sigma receptors, comparing them to healthy mice and applying non-diabetic stressors to the sigma receptor knockouts. They suspect that other stressors, including age, also cause retinal damage.

Goals include determining if retinal appearance improves as a result of the interaction between the sigma receptors and (+)- pentazocine and consequent reduction of cell stress. To help explore the therapeutic potential, they also want to see whether the drug is effective if given later in the disease process. In their earlier studies, the drug was given immediately after mice became diabetic, an unlikely stage of diagnosis for most human diabetics.

"If we can get answers to these questions we'll know better whether (+)- pentazocine has the potential to help patients, which is our ultimate goal," Smith said.

To help prevent progression of diabetic retinopathy, patients are encouraged to control glucose and cholesterol levels as well as blood pressure. Laser treatment can help destroy excessive blood vessels that hinder vision and reduce swelling often associated with the condition.

Toni Baker | EurekAlert!
Further information:
http://www.mcg.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>