New tech holds tissue still for cellular imaging

UCSF researchers are able to hold a mouse's lung tissue still long enough to image individual cells, which could help them see how cells respond to injury and disease, according to their report.

Motion can present major challenges in photography in general, not to mention with medical imaging techniques such as MRIs. But a new method using simple suction appears to stabilize living lung tissue without disrupting normal organ function long enough to image the live interactions of living cells, including immune response to injury.

Lung cells, highlighted in green, are photographed using a cell-stabilization method of gentle suction and fast photography. E. Thornton and M. Looney

With more than 20 articles about microscopy under their belts, researchers at the University of California at San Francisco publish their latest findings in this month's issue of Nature.

"The nature of disease is complex, so if scientists can observe in real-time what's happening in tumors or immune responses as they occur, we can find new ways to intervene," says senior author Max Krummel, associate professor of pathology whose lab developed the new technique.

Using microscopes custom-built in their own lab, the researchers turned to their own light-based hi-res imaging technique--using infrared-pulsed lasers--to penetrate deep into tissue layers and observe immune cells in lymph nodes as small as a micron in diameter.

This time, in an attempt to see living lung tissue in mice, they built a device that applied a "gentle" amount of suction to the surface of the region they wanted to view. Their super-fast imaging took 30 photos a second, giving them a view of cellular behavior that had previously been too blurry to be useful.

"As a result of achieving video-rate imaging of events within the lung, we've shown how the immune system behaves during normal function and how tissues are affected in acute lung injury," says Mark R. Looney, coauthor of the paper and assistant professor in medicine. "For other disease processes in other organs, we hope to define how collections of cells participate and how they're organized."

Next up? The group plans to further tweak their suction device so that it is small enough to enable them to image live tissue biopsies.