Retinol binding protein 3 as biomarker for diabetic retinopathy
Letter to the Editor

Retinol binding protein 3 as biomarker for diabetic retinopathy

Ward Fickweiler1,2, Lloyd P. Aiello1,2,3, Jennifer K. Sun1,2,3, George L. King1,3,4

1Research Division, 2Beetham Eye Institute, Joslin Diabetes Center, Boston, MA, USA; 3Department of Ophthalmology, 4Department of Medicine, Harvard Medical School, Boston, MA, USA

Correspondence to: George L. King, MD. Research Division, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA. Email:

Provenance: This is an invited article commissioned by the Section Editor Dr. Wan Wang (Medical Technology School, Xuzhou Medical University, Xuzhou, China).

Response to: Rusciano D, Bagnoli P. RBP3: a possible prognostic marker and therapeutic target in diabetic retinopathy. Ann Transl Med 2019. doi: 10.21037/atm.2019.09.133

Submitted Oct 01, 2019. Accepted for publication Oct 22, 2019.

doi: 10.21037/atm.2019.10.95

We thank Dr. Rusciano and Dr. Bagnoli for their interest in our article “Retinol binding protein 3 is increased in the retina of patients with diabetes resistant to diabetic retinopathy” (1). Our article identified the first neuroretinal selective protein to act on retinal vasculature, suggesting numerous therapeutic and diagnostic possibilities. Several reports have suggested potential circulatory biomarkers which may be associated with severity of diabetic retinopathy (DR) (2-10). However, a major limiting factor in those studies is that the expression of those factors is not limited to the retina and are generally primarily expressed in other tissues. Thus, the circulating levels of those factors do not specifically represent retinal changes. However, RBP3 is very selectively expressed in the photoreceptors of the retina, with only very minor expression in the pineal gland. With the development of a highly sensitive and selective ELISA, we can measure RBP3 in the vitreous and accessible human fluids including the serum. Future studies are needed to elucidate the utility of circulating RBP3 levels as a biomarker for the severity or potential progression of DR.




Conflicts of Interest: The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.


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Cite this article as: Fickweiler W, Aiello LP, Sun JK, King GL. Retinol binding protein 3 as biomarker for diabetic retinopathy. Ann Transl Med 2019;7(22):706. doi: 10.21037/atm.2019.10.95