Macquarie University, NSW 2109
With generous support from the Brain Foundation, researchers at Macquarie University's Medical School have been undertaking novel research relating to the flow of cerebrospinal fluid.
The brain and spinal cord are bathed in a liquid called cerebrospinal fluid (CSF). CSF is vital to mechanical protection of the central nervous system, as well as to the normal complex function of the brain and spinal cord. It is known that CSF enters the spinal cord and brain where it helps to maintain a constant biochemical environment for precise function of brain and spinal cord cells.
Despite the critical role of CSF in some of the body’s most important functions, there is only a rudimentary understanding of CSF circulation, especially in the spinal cord. If fluid can enter, then it must also drain out of the spinal cord.
Although recent research has identified the role of blood vessels in mediating this transport of fluid, many of the details have yet to be clarified. For example, there is still controversy as to the exact arrangement of anatomical compartments around small penetrating blood vessels in which fluid exchange is thought to occur. Forces such as respiration and heart pulsations are thought to be important drivers of fluid flow around and within the spinal cord, but this is another nascent area of research.
Our laboratory group has recently demonstrated for the first time that respiratory generated pressures are the dominant drivers of spinal CSF flow and fluid entry into the spinal cord. Cardiac pulsations contribute to a lesser extent but are the principal forces in helping fluid drain from the spinal cord. At the microscopic level, we characterised the hyperdynamic movement of fluid using novel, sophisticated imaging techniques. The next step was to examine CSF flow in disease states.
Conditions like spinal cord injury and syringomyelia are related to abnormalities in fluid flow. In syringomyelia, there is an abnormal collection of fluid within the spinal cord that expands and damages the nerve fibres, leading to pain, paralysis, and sometimes, death. It is the endpoint of various conditions such as herniation of the brain through the base of the skull (Chiari malformation), spinal cord injuries and tumours, and spina bifida. Although it carries tremendous disability, treatment is often unsatisfactory, which is rooted in an incomplete understanding of how syringomyelia forms.
The research outcomes achieved so far suggest that breathing influences CSF flow. This is significant in conditions such as spinal cord injury and syringomyelia whereby breathing is often impaired. It is hoped that the results of this study will give us insight into how breathing, as well as blood pressure and heart rate, influence CSF flow. People with spinal cord injury and syringomyelia often experience cardiovascular dysfunction, causing changes in blood pressure. The results of this study will provide the first indication of whether these changes could influence fluid accumulation in the spinal cord. If so, this would suggest that these variables should be addressed clinically.
The funding from the Brain Foundation has enabled a project to be completed for a Master of Research student, which has yielded some interesting results. Another Master of Research student is continuing the project, investigating the effect of blood pressure on CSF flow in the presence of a spinal pathology. It is anticipated that the entire project will be completed in early 2024.
We thank the Brain Foundation for their support in funding this research.