Therapies aimed at replacing damaged cells with a fresh, healthy batch hold immense promise—but there remains one major sticking point: once you have injected new, healthy cells into the patient, how do you track them and how do you ensure they do the job for which they were designed?
Unfortunately, there’s no easy solution. The problem of tracking the movement of cells during cell therapy is that it’s hard to stay on their trail they enter the body. They can get mixed up with other, native cells, and in order to test whether the therapy is working, doctors often have to rely on taking tissue samples.
But now, scientists at the University of California, San Diego School of Medicine and the University of Pittsburgh have devised an ingenious way to keep tabs on where cells go post injection. Their findings, reported last week in the journal Magnetic Resonance in Medicine, stand to help researchers identify whether cells are arriving at the correct destination.
The research team, lead by UCSD Radiology Professor Dr. Eric Ahrens, developed something called a periflourocarbon (PFC) tracer in conjunction with MRI technology. Testing this new technology in patients receiving immune cell therapy for colorectal cancer, the team found that they were better able to track the movement of the cells than with traditional methods.
“This is the first human PFC cell tracking agent, which is a new way to do MRI cell tracking,” said Ahrens in a news release. “It’s the first example of a clinical MRI agent designed specifically for cell tracking.”
They tagged these cells with atoms of fluorine, a compound that normally occurs at extremely low levels. After tagging the immune cells, the researchers could then see where they went after being injected. Importantly, the team found that more than one-half of the implanted cells left the injection site and headed towards the colon. This finding marks the first time this process had been so readily visible.
Ahrens explained the technology’s potential implications:
“The imaging agent technology has been shown to be able to tag any cell type that is of interest. It is a platform imaging technology for a wide range of diseases and applications.”
A non-invasive cell tracking solution could serve as not only as an attractive alternative to the current method of tissue sampling, it could even help fast-track through regulatory hurdles new stem cell-based therapies. According to Ahrens:
“For example, new stem cell therapies can be slow to obtain regulatory approvals in part because it is difficult, if not impossible, with current approaches to verify survival and location of transplanted cells…. Tools that allow the investigator to gain a ‘richer’ data set from individual patients mean it may be possible to reduce patient numbers enrolled in a trial, thus reducing total trial cost.”
What are the ways scientists see stem cells in the body? Check out our Spotlight Video on Magnetic Particle Imaging.