Abstract
Purpose :
An abnormal accumulation of unfolded or misfolded proteins, known as ER stress, can lead to apoptosis or autophagy. The GRP78, a member of the heat-shock protein 70 family, is a widely used ER stress marker protein. In this study, we explored the glucose-regulated protein 78 (GRP78) in aqueous humor of patients with diabetic macular edema (DME).
Methods :
We enrolled eyes with a macula thickness > 300 µm due to DME. We measured the concentrations of GRP78, Interleukin (IL) -1β, IL-2, IL-8, IL-10, IL-17, placental growth factor, and vascular endothelial growth factor (VEGF) in the aqueous humor of 66 naïve DME patients. All patients underwent a ophthalmic and systemic examinations at initial visit. We also evaluated changes in the central subfield thickness (CST) and BCVA at the 1 month visit after three consecutive monthly intravitreal bevacizumab (IVB) injections. Systemic and ocular factors associated with aqueous GRP78 levels were identified.
Results :
GRP78 levels were associated with the VEGF levels and the duration of diabetes (p = 0.016 and p = 0.037, respectively). However, no statistical significance was observed between GRP78 levels and other systemic or ocular factors. The aqueous levels of interleukins and responsiveness of IVB injection in DME also had no correlation with the GRP78 levels in aqueous humor.
Conclusions :
We showed that there is a correlation between GRP78 and VEGF levels in aqueous humor. However, GRP78 levels were not associated with the responsiveness of anti-VEGF or inflammatory biomarkers in DME patients.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.