Purpose
To compare the salivary proteomic profile of diabetic patients in different stages of diabetic retinopathy, to discover potential diagnostic or prognostic markers for diabetic retinopathy and to study the association oral health and diabetic retinopathy
Methods
The proteomic profiles of three pooled unstimulated whole saliva samples from 15 diabetic patients with no diabetic retinopathy (NoDR), 15 patients with non-proliferative diabetic retinopathy (NPDR) and 15 patients with proliferative diabetic retinopathy (PDR) were analyzed by using LC-MS/MS (Liquid chromatography-mass spectrometry/mass spectrometry, Orbitrap fusion tribrid mass spectrometer)
Results
315 proteins were identified in our study and 119 of them were differentially expressed. Among the 119 proteins, one protein (metalloproteinase inhibitor 1) was up-regulated proportional to the severity of DR; two proteins (peroxiredoxin-1 and unconventional myosin-IXb isoform 2) were down regulated in NPDR and were not detected in PDR. The discovery of unconventional myosin-IXb isoform 2 in saliva was a novel finding as it has not been reported in saliva. A group of proteins (116 proteins) were significantly up-regulated in PDR group but were down-regulated or not detected in NPDR compared to NoDR group.
Conclusions
Saliva is a potential body fluid to investigate the pathogenesis and pathophysiology of diabetic retinopathy and discover possible diagnostic and prognostic biomarker of diabetic retinopathy. Proteomic analysis is a useful method for this discovery study.