Here is a way of doing protocols for metabolomics:
One of the primary roles of adipose tissue is to store energy in the form of triglycerides. These are hydrolysed during periods of fasting within the body to release free fatty acids and monoacylglycerides. However, in order to function as a cell, adipocytes also require phospholipids for cell membranes around the cell and intracellular organelles. Furthermore, in obesity or other states where the storage capacity of adipocytes may be exceeded , reactive lipid species such as lyso-phospholipids and diacylglycerides can be detected within adipose tissue. Such lipid species may be responsible for the development of insulin resistance within adipose tissue as part of lipotoxicity .
Recently there has been increased interest in both brown adipose tissue and the browning of white adipose tissue as a potential target for treating type 2 diabetes, obesity, dyslipidaemia and atherosclerosis [3,4]. In both tissues fatty acid oxidation can be stimulated by either physiological or pharmacological interventions. In order to oxidize fatty acids they must be first transported across the inner mitochondrial membrane across the carnitine shuttle.
Furthermore, adipocytes are not the only cell type in adipose tissue. Macrophages play an important role in adipose tissue inflammation, and potentially may cause insulin resistance in this tissue. This activation is in part brought about by the production of eicosanoids.
This chapter deals with a series of lipidomic methods for the profiling of different lipid species important for understanding adipose tissue biology. These tools use both gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS) to profile the lipidome in both adipose tissue and adipocytes. While there are a variety of analytical methods used to profile lipids using mass spectrometry in the literature the methods detailed here should provide a good starting place for the development of new mass spectrometry method, and all have been validated for adipose tissue.