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Piotr Walczak on Visualizing Stem Cell Treatments


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Piotr Walczak on Visualizing Stem Cell Treatments

Interviewed by Rachel Butch

Piotr Walczak on Visualizing Stem Cell Treatments
Piotr Walczak is an associate professor of radiology and radiological science. He develops noninvasive imaging techniques to monitor stem cell therapies for neurological disorders, particularly those that affect the protective myelin sheath around nerves. 

What topics do you investigate? 

Walczak: My group focuses on regenerative medicine and developing therapies for brain diseases through imaging. We transplant stem cells into our test animals and use powerful imaging techniques that allow us to see the cells, follow them and monitor their effects in live animals. 
For this, we mainly use MRI and bioluminescence. For MRI, we label the cells with nanoparticles so that when they are transplanted, we can see if and where the cells integrate in a living brain. For bioluminescence, we take a gene from fireflies — the one that allows them to flash their lights at night — and insert it into mammalian stem cells. When the cells are transplanted, we can pick up that luminescent signal using a special camera. This allows us to see whether the transplanted cells are alive and growing or if they were rejected by the body.  
testimg Piotr Walczak (middle) with postdocs students and colleagues.
Animal studies with stem cells are very complex. It often takes a very long time to see therapeutic effects after cell transplantation; in some models, it may take a year to see results. With the new techniques, you can tell at any given time if the transplanted cells are alive and whether they are working. This allows for much more efficient experiments. 

What is the outlook for stem cell therapies to repair brain injury in humans?

Walczak: Our work here is all in animal models. However, people have done stem cell therapies in humans for neurological diseases, including stroke, Parkinson’s disease and Lou Gehrig's disease. These clinical studies were all in phase I, which measures safety. They do appear to be safe, but in terms of efficacy, the effects are small, if any, indicating that more preclinical work needs to be done. The problem is that these early clinical trials were based on studies in rodent models. Translating these treatments, which have had spectacular success in mice, to humans failed. Clearly, we need better, more clinically relevant models to incorporate into the translational pipeline. To address this problem, my group is now performing studies in large animals, including pigs and dogs. 

How did you become interested in this field? 

Walczak: I loved biology when I was a kid. It was fascinating to me how the body works, and I wanted to understand that. I went to medical school in Poland. I never saw myself as the typical practicing clinician seeing patients every day, but I knew medicine is what I love and that it would open up a lot of opportunities for my career. When we studied neurology toward the end of medical school, I was fascinated by the discipline, but it was frustrating to me that there were so few therapeutic options we could offer patients. So I decided to focus on research in neurology — I wanted to develop something new. 

What are you most excited about? 

Walczak: There are many other fields in which regenerative medicine approaches apply, and neuro-oncology is one I am particularly excited about. Right now, many brain tumors cannot be removed because it would inflict too much damage on the patient’s brain tissue. But we could use more aggressive therapies if we had the tools to repair the damage using stem cells. I’m working to create a program where stem cell biologists, neuro-oncologists and neurosurgeons would work together to explore solutions to this problem.