The brain floats in a sea of cerebrospinal fluid (CSF) that protects it from injury. It supplies nutrients and removes waste products. Disturbances in normal fluid flow are associated with neurological disorders such as Alzheimer’s disease and hydrocephalus. A condition in which there is too much fluid in the brain.
CSF is essential for the development and function of the central nervous system.
Researchers at Washington University School of Medicine in St. Louis have developed a new technique to track fluid circulation patterns in the brain. They found in rodents that the fluid flows to areas critical to normal brain development and function. The scientists also found that circulation appears abnormal in young rats with hydrocephalus, a condition associated with cognitive impairment in children.
These findings are published online in Nature Communication. They suggest that the fluid that washes around the brain is known as cerebrospinal fluid. It may play an underappreciated role in normal brain development and neurodevelopmental disorders.
Jennifer Strahle, MD, associate professor of neurosurgery, pediatrics and orthopedic surgery, said: “Disrupted CSF dynamics may be responsible for the brain developmental changes we see in children with hydrocephalus and other brain developmental disorders.”
A pediatric neurosurgeon Strahle said: “Our next steps are to understand why the CSF flows specifically to these neurons and what molecules in the CSF are transported to these areas. Growth factors in the CSF may interact with these specific neuron populations to mediate development, and disrupt these interactions. can lead to different disease outcomes.”
The scientist also said: “The idea that CSF can regulate neuronal function and brain development is not well understood.”
Hydrocephalus often leads to cognitive dysfunction that persists after the excess fluid has been successfully drained. The disrupted CSF dynamics in these functional brain regions may ultimately affect brain development. Normalizing CSF flow in these areas is one possible approach to mitigating developmental problems. It’s an exciting field and they’re just beginning to understand the many functions of CSF.
They treat children with hydrocephalus at St. Louis Children’s Hospital. “A range of neurological disorders in young children, including hydrocephalus, are associated with developmental delays. In many of these disorders, the underlying cause of developmental delay is unknown. It is possible that in some cases there is an altered function of the areas of the brain through which cerebrospinal fluid circulates.”
Strahle, Shelei Pan, an undergraduate student, and her colleagues developed an X-ray imaging technique using gold nanoparticles to visualize the brain’s circulation patterns in microscopic detail. Using this method, they showed in young mice and rats that cerebrospinal fluid enters the brain through small channels, mainly at the base of the brain, a pathway not seen in adults. In addition, they found that CSF flows to specific functional areas of the brain.
Further experiments showed that hydrocephalus decreases CSF flow to specific neuron groups. Strahle and colleagues studied a form of hydrocephalus in some premature babies. Premature babies often have cerebral hemorrhages around birth that can lead to hydrocephalus and developmental delays.
Strahle and her team have initiated a process in young rats that is similar to that in premature babies. After three days, the tiny channels that carry CSF from the outer surface of the brain to the center were smaller and shorter, and blood flow to 15 of the 24 neuron clusters was significantly reduced.
“These functional areas contain specific collections of cells, many of which are groups, and they are connected to important anatomical structures of the brain that are still developing.”
- Jennifer M. Strahle, Pan, et al. Gold nanoparticle-enhanced rodent X-ray microtomography reveals region-specific cerebrospinal fluid circulation in the brain. Nature communication. DOI: 10.1038/s41467-023-36083-1