When the light-sensitive layer from inside the back of the eye detaches, a “black curtain descends” and patients are left almost instantly blind. Even after visiting a retina specialist to fix the retinal detachment (RD), the patient’s trouble may be far from over.
Proliferative vitreoretinopathy (PVR) is the most common complication after a repaired RD. PVR is scar tissue that develops within the eye. It occurs in 5-10% of RD patients.
Vision loss may also persist if the macula is affected by the RD.
Colleen Cebulla, MD, PhD, an OSU retina specialist, is trying to find out why these scars form and what can be done to prevent them. She is also studying ways to protect the damaged retina. Dr. Cebulla was awarded a National Institutes of Health funded KL2 Grant through The OSU Center for Clinical & Translational Science. She chose to develop animal models to study which proteins are important for RD and PVR. When they are identified, they can potentially be targeted for clinical therapy.
Proteins are the machinery of cells and tissue. They provide structural support, defense against germs, and a host of other functions. Utilizing proteomics (the large-scale study of proteins, particularly their structures and functions), Dr. Cebulla is trying to find the protein or proteins that initiate scarring.
“I first developed a mouse model and used iTRAQ labels to individually label all the different samples,” said Dr. Cebulla. “That way, we could look at which proteins are increased or decreased in the retina during early PVR versus late PVR, compared to normal retina.”
iTRAQ (Isobaric Tags for Relative and Absolute Quantitation of protein) is a mass spectrometry technique used to quantify proteins from different sources in a single experiment. For proteomic studies, the tissue is isolated, then the protein is isolated from that tissue. Once the proteins are isolated, they are divided into smaller fragments that are labeled with iTRAQ tags, so that each different condition has a different tag. This way, the relative amounts of specific proteins from each different iTRAQ group can be determined.
“In my group of early PVR, I can see that I numerous proteins are increased compared to the control retina,” said Dr. Cebulla.
In collaboration with Andy Fischer, PhD in OSU Neuroscience, Dr. Cebulla has also developed a chicken retinal detachment model that has many more similarities to humans and has a larger eye than a mouse eye.
“The human retina has a lot of cone photo receptors and that’s what helps us see color vision,” said Dr. Cebulla. “It is especially important for our central vision. Other animals do not have that.”
“Right now, there is no pharmacologic treatment for PVR or the vision loss from detachment of the macula,” said Dr. Cebulla. “This animal model will allow us to study potential therapies for PVR or protective treatments for photoreceptors. This research is helping us to make critical connections in the lab that may ultimately translate into patient care and that’s a connection I wouldn’t miss for the world.”
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