Prostanoids in the vitreous of diabetic and nondiabetic human eyes with retinal detachment

We measured prostaglandin E₂ (PGE₂) and prostacyclin levels in the vitreous bodies of 5 eyes of patients with diabetic retinopathy complicated by rhegmatogenous retinal detachment (RRD) and compared them with the corresponding levels in 9 nondiabetic eyes with the same condition as well as with 10 control eyes of deceased patients with no known ocular pathology. We also studied the effect of surgical retinal reattachment on vitreal PGE₂ and prostacyclin levels in 4 eyes. Vitreal samples from both nondiabetic and diabetic eyes with RRD were obtained during vitrectomy, while samples from deceased subjects (controls) were obtained 2-6 h after death. Vitreal PGE₂ and prostacyclin levels in the control eyes approximated plasma levels (79.9 ± 20.5 and 124.5 ± 38.5 pg/ml, means ± SD, respectively), while RRD in the nondiabetic eyes was associated with increased levels of both PGE₂ and prostacyclin (3,170 ± 3,024 and 467 ± 283 pg/ml, respectively). In the diabetic eyes with diabetic retinopathy complicated by RRD, all of which underwent retinal photocoagulation, PGE₂ and prostacyclin levels were 2-4 times lower than those of the nondiabetic eyes with detached retina. Following surgical retinal reattachment, vitreal levels of both components in diabetics and nondiabetics showed a reduction suggesting that the surgical procedure for obtaining vitreal samples was not the cause for elevated prostaglandin levels in the eyes with detached retina. We showed that RRD is associated with an excessive accumulation of PGE₂ and prostacyclin in the vitreous, which is higher in nondiabetic than in diabetic eyes, indicating that diabetic retinopathy in laser-treated eyes might lead to reduced vitreal levels of these metabolites.