The human body is complex. The division of medical practice into subspecialties, focusing on the intricacies of a single organ or organ system, is one way health care has evolved to handle this fact. This solution, however, has its limits. And as medical research has progressed, the pendulum has begun to swing the other way—toward emphasizing the similarities between organ systems and the connections between specialties.
Such a shift makes sense to Mira M. Sachdeva, M.D., Ph.D., who recently joined Wilmer’s Retina Division. As a retina specialist, Sachdeva sees these connections every day. “You’re literally looking at part of the brain by looking into the eye. The retina is an extension of the brain,” she explains. To that end, she recently began a research project under the mentorship of a neurologist at Johns Hopkins, Ted M. Dawson, M.D., Ph.D.—“a world expert in neurodegenerative diseases, specifically Parkinson’s,” says Sachdeva.
Why is a retina specialist interested in Parkinson’s disease? The mitochondria.
Frequently referred to as the “powerhouses” of the cell, mitochondria break down nutrients (fats, sugars, proteins) taken in by the cell and combine these with oxygen to create energy-rich molecules. “I’m interested in how mitochondrial metabolism in the retina affects cell survival and how abnormalities in this can lead to cell death and loss of retinal tissue,” says Sachdeva. “Even though the specific layer of the retina involved may differ, retinal neuronal death is essentially the endpoint of many retinal diseases, including macular degeneration and diabetic retinopathy. My goal is to identify new strategies to protect retinal neurons.”
Mitochondrial dysfunction plays a critical role in Parkinson’s disease as well, which is where Dawson’s research comes into play. “Dr. Dawson studies pathways of mitochondrial function in the dopamine-producing neurons in the brain that, when perturbed, contribute to neurodegeneration in Parkinson’s disease,” says Sachdeva. “I’m starting to look at whether there are parallel pathways in the retina that contribute to retinal neurodegeneration in diabetes.”
She thinks this line of inquiry could complement the existing focus of diabetic retinopathy research and treatment—which is on retinal blood vessels. Abnormalities in the retinal blood vessels are the diagnostic hallmark of the disease, Sachdeva says. And current treatments for diabetic retinopathy, such as antivascular endothelial growth factor (anti-VEGF), target those blood vessels.
“But there’s more and more evidence coming out that even before you see changes in blood vessels in patients with diabetes, you can see loss of retinal neurons. No one knows what causes this early retinal neurodegeneration in diabetes,” she says. “And if we could target another pathway and even another cell type, we might be able to prevent vision loss further. It’s exciting.”