High-Speed, In Vivo Raman Technique Pinpoints Cholesterol

A new high-speed spectroscopy technique that can pinpoint where cells store cholesterol could be used to study obesity and diabetes.

Researchers at Purdue University used hyperspectral-stimulated Raman-scattering microscopy to map lipid metabolism in living C. elegans roundworms.

Ordinarily, cells have to be processed before they can be analyzed, which rules out studying living cells. Meanwhile, conventional Raman microscopes may take hours to get results. But the new method can be used on living specimens and works at high speed, enabling researchers to measure changes in real time in live animals.

Researchers used hyperspectral-stimulated Raman-scattering microscopy to map lipid metabolism in C. elegans. Courtesy of Ji-Xin Cheng/Purdue University.

“The advantage of being able to observe what is happening in real time in a live tissue is that you can follow the same cell over time, just like following the same person over time to track a patient's health,” said professor Dr. Ji-Xin Cheng.

Examining the vibrational “fingerprints” of molecules within the worm showed that cholesterol is stored in lysosome-related organelles, compartments inside intestinal cells containing digestive enzymes. The approach makes it possible to quantify not only the storage of cholesterol, a type of lipid, but also the desaturation and oxidation of lipids, which may reduce the ability of cells to use insulin.

“Now we can answer the important questions of how lipid stores change in response to diet and age,” said professor Dr. Heidi A. Tissenbaum.

The work was funded by the National Institutes of Health and the William Randolph Hearst Foundation.

The research was published in Angewandte Chemie (doi: 10.1002/anie.201406029).

For more information, visit www.purdue.edu.