The research project, the first of its kind, is called LIPID MAPS (Lipid Metabolites and Pathways Strategy). It identified and measured 588 lipid species under eight categories. These types of fat provide energy, build cell walls and acting as signaling molecules.
“One of the things that was very useful was that we’ve never done an analysis of human plasma before, so we were able to develop methodologies, [which] helped us discover new lipids that were previously unknown in human plasma,” research associate Aaron Armando said.
With the help of 12 laboratories at nine universities, medical research institutes and companies, UCSD researchers put together profiles that include the genes, structures and functions in body systems, processes and diseases.
“Using our methods that looked for much more than previously known, we were able to find and quantify more lipids than [has] ever been previously done,” Armando said. “[By creating this lipidome, it’s] not only having those reference standards but also increasing the knowledge of lipids in plasma.”
The 588 are only a minimum for the number of lipid species. The upper limit of species has not been determined yet, but it is estimated that it will reach in the ten thousands.
The number was based on a new human plasma reference material, which was put together by gathering plasma samples from 100 individuals who underwent overnight fasting. These individuals were between 40 and 50 years of age and their ethnicities and gender were representative of the U.S. population.
The project provides information, research data and tools on lipid metabolism and the role of lipids in health and risks like diabetes, stroke and cancer.
The UCSD team focused on compiling 107 profiles of fatty acyls — which are one of the most fundamental categories of lipids — that include fatty acids and eicosanoids.
Fatty acids — considered good fats used for energy — help in digesting cholesterol in the arteries and regulating blood pressure. In addition, they can signal molecules in diseases.
Eicosanoids are hormones that play large roles in the immune system, acting as messengers in the central nervous system for processes like fevers, inflammations or regulation of blood pressure.
Researchers said the challenge in mapping lipids is their abundance and diversity compared to other basic molecules, like sugars and amino acids that are limited to certain types and variations.
Before compiling the lipidome, not much was done to gather knowledge about lipids.
“Normally, when you get your blood drawn, the doctor looks at things like cholesterol and triglycerides, but there hasn’t been anything really established for most of the other lipids,” Armando said. “It’s never been done to the diversity that we’ve done it.”
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