Lipocalin-like prostaglandin D synthase in subretinal fluid of detached retinas in humans

BACKGROUND: The presence of lipocalin-like prostaglandin D synthase (L-PGDS), a dominantly brain derived protein in the cerebrospinal fluid (CSF) with a low concentration in serum, in the subretinal fluid (SRF) of detached retinas, has not been reported. L-PGDS has been demonstrated in the ciliary body and the retinal pigment epithelium in rats. METHODS: SRF was sampled during surgery (scleral buckling) of rhegmatogenous retinal detachments in 20 eyes. Biochemical and nephelometric analysis for L-PGDS concentration were performed. Albumin concentrations were determined in the same samples. RESULTS: L-PGDS concentrations in SRF (mean 18.9 mg/L +/- 14.8 mg/L) were markedly higher than the normal L-PGDS concentration in serum (>0.55 mg/L) and appears to decrease with the duration of the retinal detachment (P = 0.0064). CONCLUSIONS: As the subretinal space is not accessible in attached retinas there are no data on normal levels of L-PGDS in the subretinal space. The L-PGDS concentrations measured in the SRF of detached retinas are on average 34 times higher than normal L-PGDS serum concentration and about in the range of normal L-PGDS CSF concentration (15.3 mg/L). As the concentrations of L-PGDS exceed normal serum levels, a choriocapillary transudation is highly improbable as the source of L-PGDS in SRF of detached retinas.