This Small Business Innovation Research Phase I project addresses the unmet medical need to non-invasively obtain sufficient numbers of fetal cells for prenatal diagnosis of chromosomal abnormalities and genetic diseases. Currently, the invasive procedures of amniocentesis or chorionic villus sampling are used to physically remove fetal cells from amniotic fluid or placenta for prenatal genetic analysis. These invasive procedures carry significant risk to both mother and fetus. The overall goal of the proposed project is to develop technology to isolate and expand fetal trophoblast cells from maternal peripheral blood for non-invasive prenatal diagnostics. Fetal trophoblast cells are present in insufficient numbers in maternal peripheral blood for direct use in existing commercial prenatal diagnostic tests. The technical challenge that will be addressed in this proposal is to exploit the natural characteristics of fetal trophoblast cells to selectively expand them in culture by modifying culture conditions to obtain a sufficiently high concentration of fetal trophoblasts for prenatal diagnostic testing. The proposed Phase I project will deliver groundbreaking advances in isolation and expansion of fetal trophoblast cells necessary for innovative development of a device and technology for microfluidic isolation and expansion of fetal trophoblasts from maternal peripheral blood for non-invasive prenatal diagnostics.
The broader impact/commercial potential of this project is that our innovative technology will replace the current invasive methods of fetal cell collection for prenatal diagnosis of genetic disease. With our technology, fetal cell collection can be performed non-invasively in the first trimester, thus permitting earlier diagnosis of genetic disease which, in turn, will provide for better care of the mother and unborn infant. Our technology provides the simplest, most direct, and most cost-effective approach available for obtaining fetal cells. Approximately 300,000 women have an invasive amniocentesis or chorionic villus sampling procedure performed to collect fetal cells for screening for chromosomal abnormalities. After initial introduction of our technology, later market penetration will permit this technology to replace current pre-screening blood tests, a current available market of approximately 2.5 million patients per year in the US alone. Potential market size for our technology is approximately $1.4 billion per year. Several clinical diagnostics companies have expressed interest in purchasing a microfluidic separation device that can capture fetal cells of sufficient number and purity from maternal peripheral blood. Clinical diagnostics labs would use the captured fetal cells in their downstream genetic analyses.
Our company, Parsortix, Inc has developed technology that enables very fine separation of cells. Since cell separation and examination is important in medicine, it follows that our technology can be used to create medical tools. One way in which we are doing this concerns amniocentesis in pregnancy. In some pregnancies, the fetus may be at risk of genetic disease and, in such cases, the only way for doctors and parents to be certain is to test a small sample of fetal tissue. However, this is currently only possible by inserting a needle through the mother’s side and into the placenta; a procedure (amniocentesis) that is unpleasant and risks injury to the fetus. We are working on a way to obtain fetal cells without this discomfort and risk of amniocentesis. It happens that, as part of its development, a very small number of cells from the fetus find their way into the mother’s blood, and doing medical tests on a blood sample is much easier and less intrusive than an invasive process like amniocentesis. So, potentially, the tests for fetal disease might be performed on cells isolated from blood. The difficulty with this, however, is that the fetal cells are extremely rare and are hard to isolate from the huge mass of blood cells. Parsortix has developed a simple to use device that enables cells to be separated on the basis of their size and how compressible they are. When blood is passed through it the cells encounter a series of "steps" that result in the size of channels they pass through becoming progressively smaller. Many of the blood cells pass straight through the device and are eliminated, but a small proportion have a combination of size and compressibility that leads to them being held fast at particular points along the direction of flow in the cassette (in other words they are captured) – and this includes fetal cells when the blood sample is from an expectant mother. Parsortix had demonstrated that we can isolate and identify blood borne fetal cells in this way, and this generated the potential for a new, non-invasive technique that might replace amniocentesis. A concern, though, was that because the number of isolated cells is very small (because they are so rare), it might be difficult to do perform the required diagnostic techniques on them. The National Science Foundation helped us by funding research to determine the feasibility of a possible approach to enrich fetal cells captured in our device by purifying them further from residual blood cells that remain, then attempting to make them proliferate so their numbers increase. The main technique we attempted to use was cell migration. The fetal cells sometimes travel within other tissues, and this characteristic can be used experimentally by having the cells cross through a thin porous barrier (a membrane). We were able to induce this behavior, but found that it was not unique enough to work well in enriching the fetal cells – some of the blood cells also crossed the membrane. Nevertheless, we were able to show that fetal cells remain alive after they have encountered the treatment needed to make them cross the membrane, and thus have potential to proliferate in culture. In addition, though the migration approach did not provide exactly the solution we hoped for in improving our fetal cell isolation technique, the information and new capability we have obtained during this NSF project is likely to help us in another medical application. This other application is isolation of Circulating Tumor Cells (CTC) – cells from cancers that find their way into the patient’s blood and are believed to have great potential for diagnosis of the disease and making decisions regarding its treatment. Once again, these are rare, but our device is able to isolate them and enable their identification and analysis, and we are developing new products intended to make CTC analysis accessible and useful to physicians. Our NSF project has therefore provided crucial guidance on which techniques that will be practical and impractical for improving isolation and diagnosis of fetal cells using our technology, thereby bringing non-invasive fetal diagnosis closer. And it has contributed to our more recent development of products that will improve diagnosis and management in cancer, with real potential to improve the prospects of cancer patients.
