A new lymphatic human brain cell type has been discovered by University of Queensland scientists who were spurred on in their research by studying tropical freshwater zebrafish. The lymphatic system plays a vital part in the immune system and is part of the circulatory system. However, the brain is the only organ in the human body without a lymphatic system, so the scientists asked why these cells are lymphatic in nature. They observed that the cells appear to be the zebrafish version of cells described in humans called “mato” or lipid laden cells, which clear fats and lipids from the system, and suggested that equivalent cells may surround and protect the human brain from a build-up of cellular waste. Their research focus now is to investigate how the newly discovered cells function in humans and how they might be controlled with existing drugs to better understand and treat neurological diseases such as stroke and dementia.