Hydrocephalus patients suffer from long-term deficits in both neurologic function and overall quality of life. Current treatments in the field, most of which involve diversion of cerebrospinal fluid (CSF) with shunts, recurrently fail. Despite our efforts for 60 years, shunts still have the highest failure rate of any neurological device: 98% of all shunts fail after ten years. This failure rate is the dominant contributor to the $2 billion-per- year cost that hydrocephalus incurs on our health care system. Shunts fail after becoming obstructed with attaching glia, creating a substrate for more glia or other cells and tissues (e.g. choroid plexus) to secondarily bind and block the flow of CSF through the shunt. Since glial attachment is a primary mechanism for shunt failure, we need to prevent it by inhibiting surface interactions with proteins, astrocytes, and microglia. Tethered liquid perfluorocarbon (TLP) coatings stably adheres a thin, inert liquid perfluorocarbon layer that prevents protein and cell attachment and subsequent activation. Previously developed solid surface coatings, even solid perfluorocarbon coatings, allow for some level of surface attachment and activation, which eventually leads to recruitment of thrombotic proteins and inflammatory cells. The omniphobic liquid surface repels hydrophilic and hydrophobic proteins, preventing recruitment and downstream cascades from initiating on the surface and leading to clogging. Based on our preliminary data which shows stability, low neurotoxicity, decreased protein adsorption, cell attachment, blood pooling, and tissue response, this is a top candidate to reduce shunt failure rate. In our first approach, we refine our coating technology to develop a durable and uniform coating. We measure initial surface characteristics, test durability under high flow rates and following purposeful scratching and bending, and assess the impact any free-floating TLP coating may have on shunt functionality.
Our second aim begins to biologically analyze these relationships in a 3D culture system, designed and validated specifically to incorporate the shunt environment. By using quantitative immunofluorescence to identify attachment, activation, migration, proliferation, and binding strength, we will begin to understand the mechanisms of obstruction with and without the TLP coating. In this way, we can use these data to make specific hypotheses-driven design changes. Finally, in our third approach, we will test toxicity in the brain and systemically by inserting TLP coated shunts into the rodent brain. This Phase I project sets FreeFlow apart from others with its novel TLP coating that will reduce shunt failure. This project will set the stage for Phase II pre-clinical trials.
Hydrocephalus patients have a severely diminished quality of life and suffer from long- term neurologic deficits because of the inevitable failure of shunts used to treat. In this project, our team of engineers, neurosurgeons, chemists, and biological experts will develop a stable and uniform coating that reduces glial cell attachment in a clinically significant way, while also identifying how it works in order to maximize impact. By studying efficacy and mechanism of action in a 3D cell culture model, and safety in an in vivo model, we embrace a multi- disciplinary approach that will provide a better understanding and a new, modified shunt, that can be tested in pre-clinical trials.
