Tear proteome in uveitis

Abstract

AbstractPurposeUveitis represents the fourth commonest cause of legal blindness in adult patients. Analysis of tear fluid proteins in acute anterior uveitis (AAU) patients could represent a novel diagnostic modality. This study aimed at detecting potential tear fluid biomarkers in patients with AAU and bacterial keratitis (BK).MethodsFourteen patients with unilateral AAU, seven patients with bacterial keratitis (BK) and 14 healthy age‐ and sex‐matched control subjects were included. Tear fluid samples were obtained by inserting two Schirmer’s test strips behind the lower eyelid of each eye for five minutes without anesthesia. Proteins were then identified by liquid chromatography tandem mass spectrometry. Pooled tear fluid samples from healthy controls were compared with samples from AAU and BK patients, respectively. Ingenuity Pathway Analysis (IPA) was used to explore biological function.ResultsA relative protein level was obtained for 235 proteins in AAU patients and 198 proteins in BK patients, while using healthy control subjects as reference. In AAU patients, nine proteins were at least two‐fold up‐regulated, whereas in BK patients, 12 proteins were up‐regulated more than two‐fold. None of the top ten upregulated proteins in AAU and BK overlapped. The top canonical pathway identified by IPA was ‘Acute Phase Response Signaling’ in AAU and ‘LXR/RXR activation’ in BK. Top upstream activated regulators included peroxisome proliferator activated receptor delta in AAU and interleukin 6 in BK.ConclusionsTear fluid protein analysis represents a promising diagnostic modality for ocular inflammatory diseases and demonstrate differentially expressed proteins in acute anterior uveitis and bacterial keratitis.