Altered concentrations of soluble CD163 in the vitreous of patients with proliferative diabetic retinopathy after vitrectomy

Abstract

Purpose : We recently reported that CD163, a specific marker for M2 macrophages, is involved in the formation of preretinal fibrovascular membranes present in eyes with proliferative diabetic retinopathy (PDR). The purpose of this study was to determine whether the vitreal concentration of soluble CD163 (sCD163) is altered after vitrectomy in eyes with PDR.

Methods : Vitreous samples were obtained from 262 eyes of 214 patients with PDR and 79 eyes of 79 patients with macular hole (MH) as control just prior to pars plana vitrectomy. We also collected vitreous samples from 50 eyes of patients with PDR before vitrectomy without IOL implantation and the same eyes during secondary IOL implantation approximately 6 month after the initial vitrectomy when the activity of retinopathy had calmed down (successful group). Additionally, vitreous samples were collected during both initial and the second vitrectomy from 15 eyes of PDR patients who required a re-operation (unsuccessful group). The levels of sCD163 were measured by sandwich enzyme linked immunosorbent assay.

Results : The mean vitreous concentrations of sCD163 in the samples collected before vitrectomy were significantly higher in patients with PDR than MH patients (53.49 and 6.07 pg/mL, respectively: P < 0.01). In the successful group, the levels of sCD163 in the vitreous of eyes with PDR collected at the time of the IOL implantation was significantly lower than that collected before the initial vitrectomy (7.74 and 30.88 pg/mL, respectively : P < 0.01). In contrast, sCD163 was elevated at the time of second vitrectomy compared to the initial vitrectomy in the unsuccessful group (115.79 and 32.65 pg/mL, respectively: P < 0.01). Among the patients who required re-operation, the mean vitreous levels of sCD163 in eyes with severe fibrous proliferation was higher than in those with slight or no fibrous proliferation (172.78 and 57.24 pg/mL, respectively: P < 0.05).

Conclusions : The elevated levels of sCD163 may represent M2 macrophage-dependent fibrous proliferations after unsuccessful vitrectomy.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.