In mammals, most lipids, such as fatty acids and cholesterol, are absorbed into the body via the small intestine. The complexity of the cells and fluids that inhabit this organ make it very difficult to study in a laboratory setting. The goal of the Farber lab is to better understand the cell and molecular biology of lipids within digestive organs by exploiting the many unique attributes of the clear zebrafish larva to visualize lipid uptake and processing in real time. Given their utmost necessity for proper cellular function, it is not surprising that defects in lipid metabolism underlie a number of human diseases, including obesity, diabetes, and atherosclerosis.
The Farber lab has developed an approach using larval zebrafish to visualize lipid uptake and processing in live intestinal enterocytes at the subcellular level. They developed a high-fat diet and used fluorescent lipids to track lipid processing within the absorptive cells of the intestine.
Among their findings, they confirmed that a fatty acid called oleic acid can greatly increase the uptake of dietary cholesterol. The researchers also found that in the presence of an abundance of dietary triacyglycerides, absorbed fatty acids were rapidly stored as lipid droplets. In contrast, cholesterol was stored in special structures, called endosomes, which are distinct from lipid droplets in zebrafish intestines.