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 Real-time feedback helps save energy and water
08.02.2017 | Otto-Friedrich-Universität Bamberg

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>