SBIR-STTR Award

This project will develop a working in vitro blood-brain barrier model with endothelial cells isolated from human brain microvasculature. This model will allow rapid assessment of the efficacy of drug delivery systems designed to bring pharmaceutically useful compounds to the brain parenchyma. Observed species differences in brain capillary endothelial cells-potential targets for delivery molecules-provide the rationale for developing a model based on human cells. Phase I efforts will first aim to develop techniques to isolate, culture, and characterize brain capillary endothelial cells from fresh human tissue. Once cultures are set up, efforts will be directed toward determining conditions that induce or maintain blood-brain barrier-associated properties in these cells in vitro. These characteristics include expression of appropriate biochemical markers and transport proteins. Cells will be grown on porous membranes or solid substrates. Efforts to optimize the barrier will involve examining a variety of culture conditions, including the presence of astrocytes or their products.Awardee's statement ofthe potential commercial applications of the research: Disorders of the central nervous system comprise a large pharmaceutical market estimated at $3.5 billion in the United States and $6.5 billion worldwide. Penetration of the blood-brain barrier is tantamount to effective drug-based treatment of such illnesses. Presently, poor penetration or complete lack of penetration limits effective treatment and use of certain therapeutics. An in vitro human blood-brain barrier will provide a rapid screen of potential drug delivery systems to the brain.National Institute of Neurological Disorders and Stroke (NINDS)

The availability of pharmaceutical to combat neurological disorders is limited by the existence of the blood-brain barrier (BBB), a protective vascular system preventing most blood-borne molecules from entering the brain. Methods to transport drugs across the BBB would therefore be of enormous therapeutic and commercial value. The long-term goal of this project is to develop an in vitro model for the human BBB to serve as an experimental system for the discovery and evaluation of strategies for drug delivery to the brain. This model will consist of human brain microvascular endothelial cell cultures expressing BBB-associated properties. Phase i feasibility studies, in which these cells were isolated and grown on porous substrata, led to preliminary identification of culture conditions inducing the cell monolayer to restrict solute diffusion. Building upon these data, the development of an in vitro human BBB will continue in Phase II. The first aim will be to define the optimal culture environment for the in vitro human BBB, by screening culture components to identify those that promote the most restrictive cell monolayer. Once one or more culture conditions have been chosen, further studies will characterize the in vitro human BBB by testing it for several properties exhibited by the authentic BBB. These will include BBB-associated proteins, detected with immunological and functional assays, tight junctions, examined by electron microscopy, and specific transport systems that, in vivo, allow the brain to receive essential nutrients. These studies, by addressing the extent to which the in vitro human BBB mimics the BBB in vivo, should facilitate research, in Phase III and beyond, to apply this model as an experimental system for the design and testing of innovative drug delivery systems that circumvent the BBB