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Jennifer K. Sun, M.D.

Dr. Sun is an Investigator in the Section on Vascular Biology, an ophthalmologist in Beetham Eye Institute at Joslin and an Assistant Professor at Harvard Medical School. Dr. Sun received her medical degree from Harvard Medical School and completed postdoctoral training in ophthalmology and vitreoretinal surgery at the Massachusetts Eye and Ear Infirmary. She is a Co-Investigator on seven national clinical trials, including two trials of protein kinase C-beta inhibition in the context of macular edema.

Apart from its poetic aspects, the eye gives us a literal window into the systemic effects of diabetes, a portal for noninvasively monitoring the changes that occur over time in patients with diabetes. Dr. Sun uses ophthalmologic techniques to peer through this window in the search for early markers of the neuropathic and vascular complications of diabetes, with the ultimate goal of improving visual outcomes in patients with diabetes.

In collaboration with George King, M.D., Head of the Section on Vascular Biology and Director of Research, Dr. Sun is analyzing data from the 50-Year Medalist cohort, a population of patients who have lived with diabetes for 50 years or more. Her studies of the ocular health of these patients show that a high percentage retain very good vision even this long after diagnosis; 63 percent are still 20/20, and the majority have none, or only mild retinopathy. Dr. Sun is closely examining a range of data from the patients in this cohort in the hope of identifying genetic or biochemical markers that correlate with good long-term ophthalmologic outcomes and could be therapeutically targeted in patients with diabetes who have early-stage vision complications.

Changes in the electrical signaling of the retina can be the first hint of developing retinopathy. Dr. Sun is using a technique called multifocal electroretinography (ERG) to measure the signals produced by different regions of the retina in response to light stimulation. By correlating ERG measurements with those of retinal blood flow, Dr. Sun aims to develop an algorithm that can help identify patients at high risk of developing diabetic retinopathy. This work extends beyond the ophthalmologic, as ERG changes, which are suggestive of peripheral nervous function as a whole, can also be the first sign of progressive peripheral neuropathy. Patients whose ERG readings show cause for concern can then be closely monitored and protected from complications like diabetic ulcers and other manifestations of the peripheral neuropathy associated with a long history of diabetes.

Dr. Sun is also engaged in clinical research on ways to promote better visual outcomes for people diagnosed with macular edema—swelling of the retina due to blood vessel leakage and the primary cause of vision loss in diabetes. Her research portfolio in this area includes work on direct intravitreal injection of anti-inflammatory steroids (to reduce the swelling), the use of vitrectomy (a surgical procedure in which the fluid between the lens and the retina is completely replaced) and the use of protein kinase C-beta (PKC-beta) inhibitors. Together with her mentor, Lloyd Paul Aiello, M.D., Ph.D., Head of the Section on Eye Research and Chair of several trials on PKC-beta inhibition, and other collaborators across the country, Dr. Sun is evaluating an oral PKC-beta blocking agent that may help slow or prevent macular edema or proliferative diabetic retinopathy. The development of this agent has been hailed as one of the only examples of a rationally designed treatment for diabetic complications based on meticulous clinical and biological studies of the disease processes fueled by diabetes.

Selected References
Sun JK, Miller JW. Medical treatment of choroidal neovascularization secondary to age-related macular degeneration. Int Ophthalmol Clin 45:115-132, 2005.

Sun JK, Arroyo JG. Adjunctive therapies for proliferative vitreoretinopathy. Int Ophthalmol Clin 44:1-10, 2004.

Sun JK, Iwata T, Zigler JS Jr, Carper DA. Differential gene expression in male and female rat lenses undergoing cataract induction by transforming growth factor-ß(TGF-ß). Exp Eye Res 70:169-181, 2000.

Carper DA, Sun JK, Iwata T, Zigler JS Jr, Ibaraki N, Lin LR, Reddy V. Oxidative stress induces differential gene expression in a human lens epithelial cell line. Invest Ophthamol Vis Sci 40:400-406, 1999.

Coll GE, Chang S, Sun J, Wieland MR, Berrocal MH. Perfluorocarbon liquid in the management of retinal detachment with proliferative vitreoretinopathy. Ophthamology 102:630-638, 1995.

Page last updated: October 21, 2014