Abstract
Presentation Description :
The “metabolome” is defined as the mixture of all small molecule compounds detected in a tissue or biofluid. The components can be metabolites generated by metabolic pathways operating within the lens as well as compounds from clinical therapeutic treatments, personal hygiene/cosmetics, food and other local environmental sources. The metabolome offers a window into the physiology of the lens since in this tissue gene transcription is limited to outermost regions of the lens. Besides lens tissue, one must also consider the aqueous humor that bathes the lens, the vitreous humor and tears. The metabolome is measured by either proton nuclear magnetic resonance (NMR) or mass spectrometry in combination with separation methods such as gas chromatography (GC-MS), liquid chromatography (LC-MS) and capillary electrophoresis (CE-MS). Several metabolomics studies have been reported on the lens. NMR has the advantage that it is quantitative, reproducible and non-destructive, but is limited to the number of metabolites that can be measured; in contrast, LC-MS is several orders of magnitude more sensitive, can detect thousands of metabolites, but requires individualized methods to generate quantitative data. Recovery of the metabolome is an important issue. Magic-angle spinning NMR permits the in situ study of the metabolome of the lens without the need for extraction. Since the lens and surrounding tissues/fluids have distinct morphological zones, the distributions of components of the metabolome represent critical physiological information. Imaging mass spectrometry (IMS) of the lens (often as a frozen section of the entire eye) allows for the localization of small molecules throughout the eye. Although the methods for processing metabolomics data using statistical and pathway analysis are well developed, a recurring feature of LC-MS and IMS is the presence of ion features that cannot be attributable to known compounds.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.