VISICORT partner Dr Thierry Le Bihan leads the proteomics group at the University of Edinburgh’s SynthSys Laboratory. His team are developing protocols for profiling proteins contained in biological samples from corneal transplant recipients enrolled into VISICORT’s bio-sampling project from five leading European Ophthalmology centres. He comments here on the unique promise (and challenges) of performing proteomic analyses on samples of tears.
Considering all biological fluids as a source of potential markers, tears are quite an attractive option as they are easily obtained by non-invasive methods compared to other types of fluids. Although tears remain a relatively complex and challenging fluid, their analysis is not as difficult as plasma or other fluids which contain a large number of highly abundant proteins. However, one of the obvious difficulties with using tears is related to the amount of fluid sample that can be obtained. There are an increasing number of proteomics studies of tears which have quickly evolved from the generation of list of proteins and method development which were published earlier (De Souza et al., 2007, Genome Biology 2006, 7:R72, doi:10.1186/gb-2006-7-8-r72).
Lei Zhou is one of the most dedicated researchers in the field of tears proteomics and is senior author of the research team that recently published an interesting method to quantify 47 proteins using a high-resolution, multiple reaction monitoring, MS-based assay (Tong et al, 2015, doi: 10.1016/j.jprot.2014.12.002). We have also seen more clinical studies of an ophthalmologic nature being performed of late. Li et al, (2014; Sci rep doi:10.1038/srep05772) published a valuable clinical study of Sjögren syndrome patients with dry eye syndrome. Other researchers have also begun to explore conditions which are beyond the ophthalmology scope such as Lebrecht et al., (2009; Cancer Genomics Proteomics. 2009 6(3):177-82) which is based on a SELDI approach to identify potential biomarkers for breast cancer in tears. Analysis of tears for proteomics is among the most recent of all bodily fluids. With mass spectrometry instruments becoming more sensitive, and in combination with other “omics” strategies, I am convinced that the use of tears as a source of potential biomarkers will expand significantly in the years to come.