Discovering the mechanism of dietary fat absorption in small intestines

Lacteal is a lymphatic vessel present in the intestinal villi of our small intestines and facilitates in the absorption of dietary fats. Recently, a group of researchers from Korea Advanced Institute of Science and Technology (KAIST) has published an article in Nature Communications, emphasizing the importance of stromal cells in lacteal function and regulation.

The research team discovered that stromal cells, a connective tissue cells of an organ, produce a type of protein called YAP/TAZ. Not only do they produce YAP/TAZ proteins, but the stromal cells are also essential in regulating the transportation of digested fats from the villi via lacteals. According to the study, YAP/TAZ proteins react to physical stimulation and regulates cell differentiation and division, affecting organ growth.

The team created a mouse model to identify lacteal function in response to the amount of YAP/TAZ proteins produced from nearby stromal cells. When YAP/TAZ protein were overproduced, there also was an increase in the production of a growth factor called VEGF-C. This consequently led to abnormal proliferation of lacteals. Furthermore, excessive proliferation of lacteal caused a significant decrease in the ability to absorb dietary fats.

Interestingly, depletion of YAP/TAZ proteins also caused a decline in the ability to absorb dietary fats from the small intestines. These findings underline the idea that production of VEGF-C growth factor is essential for lacteals to function normally.

Moreover, the research team also discovered that physical intestinal activity regulates the production of YAP/TAZ, consequently affecting the production of VEGF-C. Therefore, contraction and relaxation of small intestines act as a crucial factor in maintaining the function and shape of lacteals.

Interference in the uptake and break down of dietary fats can lead to increased weight, obesity, and other metabolic diseases. The research team hopes to further unravel the mechanism of lacteals and the interaction between the lymphatic capillaries and nearby stromal cells.

Seon Pyo Hong et al. Distinct fibroblast subsets regulate lacteal integrity through YAP/TAZ-induced VEGF-C in intestinal villi. Nature Communications. 2020