Abstract
Purpose :
Insulin like Growth Factor-1 (IGF-1) is known to be a non-oxygen-regulated growth factor that contributes to normal retinal vessel growth and also to vascular disruption and neovascularization in ROP patients.The purpose of this study was to characterize the expression of IGF-1 in the retina of a patient with ROP (Case 1) and compare it to a case of ROP treated with Ranibizumab (Case 2), a case of a premature infant without ROP (Case 3) and a case of an infant without history of ROP or prematurity (Case 4).
Methods :
The eyes of the deceased infants were removed post mortem and were sent to the Florida Lions Ocular Pathology Laboratory where they were processed. Infants from cases 1 to 3 died of causes related to their prematurity. Infant from Case 4 was found unresponsive by his caretaker. In addition to the regular H&E and PAS stains performed, immunofluorescence was done using an anti-IGF-1 antibody (abcam). IRB/Ethics Committee approval from the University of Miami, Miller School of Medicine was obtained for this study.
Results :
All cases except for Case 4 disclosed positive IGF-1 staining. Positive staining was present in all layers of the retina in the posterior pole and in the NFL, inner nuclear layer, photoreceptors and the spindle-shaped cell population at the vanguard in Case 1. This case demonstrated weaker staining at the demarcation line and avascular retina, when compared to Case 2. Case 1 and Case 2 demonstrated similar staining patterns for IGF-1 within the neural retina at the posterior pole. Case 3 disclosed positive but weak expression of IGF-1 within all layers of the retina.
Conclusions :
Less IGF-1 staining was observed within the retina of Case 3 and Case 1. These findings are consistent with what has been described in different studies and models regarding the changes in the blood levels of IGF-1 in utero, at premature birth, early and later phases of ROP, as well as ROP after treatment. The different expression patterns shown, may suggest that IGF-1 plays a relevant role in the pathophysiology of ROP and could represent a future target for treatment. To our knowledge, no studies have described the expression and distribution of this factor within the neural retina of patients with ROP.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.