Conrad E. Johanson, Ph.D., Director of Neurosurgery Research Interests

For nearly twenty-five years, the National Institute of Neurological Disorders and Stroke has funded Professor Johanson’s research on the ontogeny, pharmacology, and pathophysiology of the blood-brain barrier and the cerebrospinal fluid. He and his colleagues have been studying the influence of growth factors and neuropeptides on brain development and repair after the onset of hydrocephalus, ischemia, and Alzheimer’s disease.

Using an acute stroke model in rats, Dr. Johanson’s research team has shown that the transport and permeability properties of the choroid plexus determine hippocampal well-being. After transient forebrain ischemia, damage to choroid epithelial cells impairs nearby brain regions, such as the hippocampus, until the blood-CSF barrier and CSF flow recover. To understand how this occurs, the research team is evaluating the neuroprotective effects of growth factors on the choroid plexus-CSF-hippocampus system.

To study congenital hydrocephalus, Drs. Johanson and Duncan are using mutational rat models. Specifically, they are examining the molecular expression of the Na-K-Cl transporter, a key factor in CSF dynamics. With Drs. Paul McMillan and Tien Nguyen, they are doing post-translational analyses of glycoprotein expression in the brains of transgenic and diabetic animals. Ultimately, they hope to uncover the physiological and neuroendocrine causes of ventriculomegaly and compromised CSF reabsorption.

Studies show that CSF circulation worsens in Alzheimer’s disease and other dementias. Consequently, Dr. Johanson, in collaboration with Dr. Stopa’s laboratory, is assessing blood-brain barrier permeability and CSF composition in transgenic animal models of Alzheimer’s disease and normal pressure hydrocephalus. Recent funding is allowing them to further characterize ways to stabilize the interstitial fluid and prevent neuronal degeneration. Dr. Johanson would like to link basic information about CSF volume, pressure, and composition to medical problems that attend various types of neurodegenerations.