New analytical technique uncovers >100 fatty acids

Researchers have uncovered 103 new unsaturated fatty acids in human-derived samples, doubling the number of these fundamental building blocks of life previously reported in human blood plasma. The discovery was made possible via a new analytical technique that was developed at Queensland University of Technology (QUT) and described in the journal Nature Communications.

Fatty acids form the lipids essential for life. While some lipids form cell membranes, others are present naturally as triglycerides in body fat and the waxes on our hair and skin. As explained by QUT’s Professor Stephen Blanksby, the human body makes its own fatty acids but also takes up fatty acids from food that are then modified to make them fit for purpose.

“Lipids play many roles in the body — some form cell membranes, others are precursors for signalling molecules that regulate how the body copes with inflammation and the resolution of inflammation,” Blanksby said.

“This means changes in fatty acids and other lipids (complex fats made from fatty acids) in the body can provide critical clues for health and disease.

“We know that blood tests report on lipids like cholesterol and triglycerides that are linked to our health status. With further research, these new molecules could provide critical information about our bodies’ responses to diet or disease.”

QUT researchers recently developed advanced analytical technology to probe the human lipidome (all lipids in a cell) more deeply than was previously possible. Dr Jan Philipp Menzel, a postdoctoral fellow at QUT, said the technology involved a combination of liquid chromatography with a mass spectrometer modified to enable a gas-phase reaction with ozone that broke down the carbon–carbon double bonds in unsaturated fatty acids. He then developed custom software to trawl the complex datasets the team obtained to identify the novel lipids.

“It was an innovative approach that allowed us to characterise the structure of unsaturated fatty acids,” Menzel said.

“Using this process we studied human blood plasma, cancer cells and vernix caseosa — a white layer covering newborns — and found new and different fatty acids in each.

“Some of the newly found fatty acids may not originate from human metabolism but are likely present in blood plasma, for example, after being consumed in food, whereas most fatty acids found in vernix caseosa are likely to be a product of human metabolism.

“Some of our results show the same trends established in several recent publications and add to the body of evidence that fatty acid metabolism is an important aspect of the metabolism of cancer cells,” he added.

According to Menzel, it will take a concerted effort by many scientists to unravel the full biological significance of all the fatty acids that were identified in the study. “For example,” he said, “some new omega-3 fatty acids found in vernix caseosa have unusual patterns of double bonds.

“The exact structure of a biomolecule determines its biological function, a principle used extensively in biochemistry and biomedical research. Finding biomolecules with new structures (here, differences in the position of double bonds along a fatty acid chain) could be a first step towards studying new metabolic pathways or even develop diagnostic methods or treatments.”

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