To investigate the molecular composition of subretinal fluid (SRF) in central serous chorioretinopathy (CSCR) and rhegmatogenous retinal detachment (RRD) using proteomics and metabolomics.
SRF was obtained from one patient with severe nonresolving bullous CSCR requiring surgical subretinal fibrin removal, and two patients with long-standing RRD. Proteins were trypsin-digested, labeled with Tandem-Mass-Tag and fractionated according to their isoelectric point for identification and quantification by tandem mass spectrometry. Independently, metabolites were extracted on cold methanol/ethanol, and identified by untargeted ultra-high performance liquid chromatography and high-resolution mass spectrometry. Bioinformatics analyses were conducted.
In total, 291 proteins and 651 metabolites were identified in SRF samples. Compared with RRD, 128 proteins (77 downregulated; 51 upregulated) and 76 metabolites (43 downregulated; 33 upregulated) differed in the SRF from CSCR. Protein and metabolites notably deregulated in CSCR were related to glycolysis/gluconeogenesis, inflammation (including serum amyloid P component, versican), alternative complement pathway (complement factor H and complement factor H-related protein), cellular adhesion, biliary acid metabolism (farnesoid X receptor/retinoid X receptor), and gluco- and mineralocorticoid systems (aldosterone, angiotensin, and corticosteroid-binding globulin).
Proteomics and metabolomics can be performed on SRF. A unique SRF sample from CSCR exhibited a distinct molecular profile compared with RRD.
This first comparative multiomics analysis of SRF improved the understanding of CSCR and RRD pathophysiology. It identified pathways potentially involved in the better photoreceptor preservation in CSCR, suggesting neuroprotective targets that will require additional confirmation.