Researchers at the National Institutes of Health have confirmed the existence of a drainage system in the human brain.
“We literally watched people’s brains drain fluid into these vessels,” said Dr. Daniel S. Reich a researcher at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and the senior author of the study. “We hope that our results provide new insights to a variety of neurological disorders.”
Reich explained that his research team discovered the brain had vessels that are part of the body’s lymphatic system. The lymphatic system is designed to drain waste and fight infections by distributing white blood cells to various parts of the body.
“What we saw was a network of small vessels that are sitting inside the protective membrane of the brain,” Reich said. “They ran alongside blood vessels and our method did not allow us to follow them into the neck which is where they drain but we were able to verify their presence in a human being.”
Prior to the release of the study, Reich said the medical community had seen a similar system in the brain of a mouse through MRI-imaging techniques. He explained hearing of a mouse study at a conference motivated his research team to look for a similar system in the human brain.
The study selected five healthy individuals for brain imaging. The participants were injected with a magnetic dye designed to light up blood vessels when scanned with an MRI machine. The dye is also used in brain imaging to visualize the extent of diseases such as multiple sclerosis.
“For this particular study we were developing a method so we wanted to look at healthy people,” Reich said. “If we didn’t see anything in about five people, then we were barking up the wrong tree.”
Reich said two major limitations affected the conclusions of his findings.
“The first is that we didn’t study any disease process in particular, and second, the ability to image the function of these vessels or their potential dysfunction in disease,” he said. “Our work was focused on structure not function.”
The discovery, according to Reich, has the potential to make significant contributions to studying brain-related diseases.
“The connection between the brain and immune system of the body intuitively has to be important for the development of disease,” Reich said. “We’re hopeful that the work we’ve done will open the possibility of studying that in detail.”
“These results could fundamentally change the way we think about how the brain and immune system interrelate,” said Dr. Walter J. Koroshetz, director of NINDS.