Lysosomal enzymes in subretinal fluid

Abstract

Samples of subretinal fluid (SRF) from patients with primary rhegmatogeneous retinal detachment of various duration were studied using standard enzymologic techniques. The protein content in SRF increased with the duration of detachment. The activities of lysosomal enzymes in SRF, which were acid phosphatase, beta-glucuronidase, and cathepsin D, also increased with the duration of detachment. Especially cathepsin D, which was not detected in serum, was present in SRF. The activity of a nonlysosomal enzyme, i. e., lactic dehydrogenase, which was used as a marker of cell disruption and of serum transudation was the same as that of serum. Because lysosomal enzymes are known to be able to degrade cells and tissues, the enzymologic analysis of SRF contributes to our understanding of the pathology of primary rhegmatogeneous retinal detachment.

Proteome profiling of vitreoretinal diseases by cluster analysis

“…For instance, CTSD was observed in Müller cells, ganglion cells and RPE cells of physiological retina [59,60], and the expression of CTSD correlated with age-related changes of the retina [61]. Finally, CTSD levels are high in SRF from patients with RRD [62]. Here, we demonstrate that CTSD was expressed significantly higher in SRF from patients with RRD than in NPDR, PDR, or PVR.…”

“…In the RRD and PVR samples, in comparison to the NPDR and PDR samples, there were significantly higher levels of PEDF, CLU, CTSD, and TTR detected. All of these proteins were reported to exist in RPE cells or glial cells that play an important role in pathogenesis of RRD and PVR [53][54][55][56][57][58][59][60][61][62][63][64], eloquently exhibiting the breakdown of retinal integrity and the flowing in of subretinal fluids into the vitreous samples.…”

iTRAQ Quantitative Proteomic Analysis of Vitreous from Patients with Retinal Detachment

“…The RPE is the main responsible for the phagocytosis of photoreceptor outer segments and by its consecutive lysosomal degradation [ 55 , 56 ]. Lysosomal proteins were previously found augmented in the vitreous and subretinal fluid, and their levels were related to RRD duration [ 57 , 58 ]. More recently, higher expression levels of cathepsin D were found in vitreous from patients with PVR [ 14 , 21 ], confirming our results.…”

“…So, it was suggested that the increase of lysosomal digestion is a later event in RD, contributing to the photoreceptor degeneration and inflammation [ 57 ]. Also, considering the role of vitreous liquefaction in RD onset [ 3 , 4 , 7 ], it has been suggested that lysosomal enzymes, mainly cathepsin D, may be involved in the degradation of glycosaminoglycans, and collagen molecules, of rod outer segments and RHO [ 55 , 58 , 59 ]. Finally, increased cathepsin A activity in the subretinal fluid was associated with retinal degradation in RD [ 59 ].…”