Ohio State Researchers Develop First In Vitro and Ex Vivo Models of Human Arachnoid Granulations
Team at Ohio State Achieves IH Research Milestone
January 1, 2006—Researchers at Ohio State University in Columbus, Ohio recently announced that they’ve successfully grown cells from human arachnoid granulations in the brain and have created the first in vitro and ex vivo models of cerebrospinal fluid (CSF) outflow. These cells, known as pia-arachnoid cells or “cap cells,” are located at the top of the arachnoid granulations and are thought to control the uni-directional CSF flow through the arachnoid granulations. The project is being led by Dr. Steven Katz and Dr. Deborah Gryzbowski, who are also members of IHRF’s Scientific Advisory Team.
The Gryzbowski/Katz research team at Ohio State focused on growing cap cells in their lab to create the first CSF outflow in vitro model. Using donated brain tissue collected at autopsy, samples were transferred to cell culture plates, where cell growth occurred in seven to ten days. The newly grown cap cells were checked for certain proteins to determine if the cultured cells identically mimicked cap cells found in humans. The cultured cap cells were also grown on a special filter membrane designed to measure hydraulic conductivity. The cells were perfused at a fixed pressure and their hydraulic conductivity was successfully measured, indicating a successful in vitro model, as well.
Future studies of the CSF outflow in vitro model’s hydraulic conductivity will test a variety of different conditions including increased fluid pressure and the effect of Vitamin A.
The ex vivo model incorporates the entire arachnoid granulation structure, rather than only using cap cells in perfusion studies. The role of whole tissue perfusion of the human arachnoid membrane—in other words, how CSF flows through this structure—was key in this study since it is a major component of the blood-CSF barrier and can provide insight into the mechanism that triggers idiopathic intracranial hypertension. No previous work has been done on whole tissue perfusion of human arachnoid granulations.
By measuring CSF outflow through the arachnoid granulations and micro villi simultaneously, the researchers will be able to observe interaction among all cell types, thereby gaining a better understanding of the physiology.
Plans for future study include the topological examination of different sections of the arachnoid granulations; elevated pressure perfusions runs; the use of microparticles to determine where and how much of the fluid is perfusing across the membranes; and the staining of tissue for the proteins which control water movement (aquaporins).