March 27, 2006
Watching New Blood Vessels Grow Using Engineered Viral Nanoparticles
Working with a virus that infects black-eyed peas, a team of investigators at The Scripps Research Institute has developed a nanoscale probe that provides a high-resolution map of blood vessels in a living animal. More importantly for cancer researchers, these same particles can also track angiogenesis, or new blood vessel growth, triggered by tumors.
Reporting its work in the journal Nature Medicine, a research team headed by Heidi Stuhlmann, Ph.D., and Marianne Manchester, Ph.D., developed chemical methods for attaching between 70 and 120 molecules of a fluorescent dye to the surface of cowpea mosaic virus (CPMV). The large number of dye molecules create an “exceptionally bright” nanoparticle that is easily tracked in the body using a standard fluorescence imaging device.
When injected into adult mice, the labeled viral nanoparticles appeared to bind preferentially to the surface of blood vessels, both large and small. The researchers found that none of the particles escaped the blood system for up to 72 hours after injection, though the particles were taken up by the endothelial cells that line all blood vessels and capillaries. The investigators also noted that they observed no side effects associated with administration of the viral nanoparticles.
Because the nanoparticles are taken in by endothelial cells, the researchers decided to see if these optical probes could be used to track new blood vessel growth over time. In fact, the investigators demonstrated that they could follow the growth of new blood vessels triggered by tumor. As a result, these nanoparticles could provide a new tool for cancer researchers studying the early stages of tumor growth, which requires angiogenesis, and perhaps for clinical oncologists who wish to determine if anticancer therapy is stopping new blood vessel generation.
This work, which was supported in part by the National Cancer Institute, is detailed in a paper titled, “Viral nanoparticles as tools for intravital vascular imaging.” Investigators from the Università degli Studi Magna Graecia di Catanzaro, in Cantazaro, Italy, also participated in this study. An abstract of this paper is available through PubMed.