UCSB makes important advances in studies of retinal detachment

December 14, 2004

(Santa Barbara, Calif.) -- Scientists at the University of California, Santa Barbara's Neuroscience Research Institute are reporting significant advances in their studies of retinal detachment:In the January 2005 issue of Investigative Ophthalmology and Visual Science, the international team of scientists describes changes that occur in detached human retinas. In this study, Steven K. Fisher, professor of molecular, cellular and developmental biology, and Geoffrey P. Lewis, research scientist, headed the UCSB effort, collaborating with colleagues at the Moorfields Eye Hospital and the Institute of Ophthalmology at University College London.

Understanding the "glial" response is a key aspect of this study.

Glial cells are known as the "supporting cells" of the nervous system. The central nervous system (CNS) consists of both neurons and glial cells. Glial cells actually outnumber neurons in the CNS but their functions are poorly understood. It is known that glial cells surround neurons, hold them in place and supply nutrients to neurons. They insulate neurons from each other and also destroy and remove dead neurons.

The reaction of the glial cells to retinal detachment is critical to the success of surgery to correct retinal detachment. The glial response is part of an important medical condition called "proliferative vitreoretinopathy" (PVR). This condition is characterized by the growth of glial cells on the surface of the retina. In response to unknown stimuli, these cells begin to contract and can cause the retina to tear or re-detach. In humans, PVR is the most common cause of failure of retinal reattachment surgery. It occurs in five to 10 percent of all cases.

Essentially the glial cells form scar tissue in PVR. Scar tissue in one location causes the re-detachment of the retina, in another it blocks the regeneration of neurons and vision does not return. According to this and earlier studies, the data indicate that glial cell remodeling can play a clear role in the return of good vision following successful reattachment surgery. What has been a surprising new result in all of the recent studies is the extent of neuronal remodeling that occurs during the time the retina is detached.

"The structural remodeling of retinal neurons in animals following detachment has been assumed to alter synaptic connections between nerve cells and in doing so have an effect on visual outcome including reduced visual acuity or changes in color vision," said Lewis. Photoreceptors in the eyes are among the most highly metabolic cells in the body, using more energy than any others. Because of this, the UCSB researchers decided to test the use of extra oxygen to help maintain the cells after a retinal detachment. First reported by the UCSB researchers in 1999, the therapy has proved remarkably effective and is now being used by some ophthalmologists prior to surgery. Recently the UCSB team reported refinements of these results.

Normal room air has about 21 percent oxygen. In these first studies, the effects of oxygen were examined under "ideal" conditions. That is, oxygen therapy at 70 percent was begun immediately after creating a retinal detachment. However, these ideal conditions would not likely be encountered in a clinical situation because it would not be possible to administer oxygen to human patients immediately after a retinal detachment occurs.

Therefore, a new study was undertaken in which elevated oxygen was administered 24 hours after creating a detachment, thus more closely mimicking conditions commonly encountered in human patients. The results were published by the UCSB scientists in American Journal of Ophthalmology last summer. In this case, neuronal cell death and nerve cell remodeling was greatly reduced by comparison to the animals breathing normal room air, although the glial cell response was less affected than in the experiments with delivery of immediate elevated oxygen.

Assuming that it is desirable to reduce cell death and prevent the remodeling of nerve cells in detachment patients, the simple administration of elevated oxygen between the time of diagnosis and surgical repair may result in more rapid and improved recovery after reattachment surgery. Future research will include determining the effectiveness of this hyperoxia therapy when administered both before and after reattachment surgery, and methods for better inhibition of the undesirable cellular effects that lead to PVR.

This research has broad implications since the cell types involved (neurons and glia) are the same as those in the brain and spinal cord. The UCSB effort is one of a handful of research labs in the world that are studying retinal detachment in this way. The work at UCSB is unique in that the researchers have specialized using high resolution microscopy techniques to precisely map changes in protein expression and morphology in the cells.
-end-
NOTE: Steven Fisher is available at 805-893-3637, or by e-mail at fisher@lifesci.ucsb.edu
Geoff Lewis can be reached at 805-893-3611, or by e-mail at g_lewis@lifesci.ucsb.edu

University of California - Santa Barbara

Related Neurons Articles from Brightsurf:

Paying attention to the neurons behind our alertness
The neurons of layer 6 - the deepest layer of the cortex - were examined by researchers from the Okinawa Institute of Science and Technology Graduate University to uncover how they react to sensory stimulation in different behavioral states.

Trying to listen to the signal from neurons
Toyohashi University of Technology has developed a coaxial cable-inspired needle-electrode.

A mechanical way to stimulate neurons
Magnetic nanodiscs can be activated by an external magnetic field, providing a research tool for studying neural responses.

Extraordinary regeneration of neurons in zebrafish
Biologists from the University of Bayreuth have discovered a uniquely rapid form of regeneration in injured neurons and their function in the central nervous system of zebrafish.

Dopamine neurons mull over your options
Researchers at the University of Tsukuba have found that dopamine neurons in the brain can represent the decision-making process when making economic choices.

Neurons thrive even when malnourished
When animal, insect or human embryos grow in a malnourished environment, their developing nervous systems get first pick of any available nutrients so that new neurons can be made.

The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.

Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.

How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.

A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.

Read More: Neurons News and Neurons Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.