Researchers Optically Clear Blood Clots to Study Their Structure and Pathogenesis

These days blood clots are often successfully removed from the body using minimally invasive catheter-based tools. They are then summarily discarded, but researchers at the University of Pennsylvania, University of California, Riverside, and University of Notre Dame have developed an investigative non-clinical imaging technique that allows the study of the removed clots to better understand their formation and how they come to be.

This so-called “optical clearing” technique makes clots easier to see through, allowing for up to a millimeter of penetration of light into a clot. Previous capabilities only permitted about .02 of a millimeter of penetration, which did not allow for any comprehensive study of the internal structure of clots without breaking them up first.

Clots are difficult to image because they are rich with heme, a compound that includes iron in its recipe. To make clots easier to peer through, the researchers are able to remove heme from a clot while keeping everything else intact, including the clots 3D structure.

They are now able to clear a blood clot, up to a millimeter in depth, within about a day. Following, various methods, including using fluorescent markers, can be employed to peer into the clot. The team already studied a number of clots and discovered that red blood cells change their shape when compressed inside a clot and end up squeezing tightly against each other without changing the density of the cells in a given volume.

Here’s a video of a composite image of red blood cells (green) and fibrin network (orange) of a cleared mouse clot made with pre-labeled reconstituted blood that was imaged with a two-photon confocal microscope (water 25X objective, 4x magnification, z-stack obtained with 1 micron intervals from the clot surface to 748 microns deep). (Credit: Jeremiah J. Zartman, University of Notre Dame):

Study in Biomedical Optics Express: Whole blood clot optical clearing for nondestructive 3D imaging and quantitative analysis…

Via: The Optical Society…