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Using light, not surgery, for biopsies

Offering a noninvasive tool that gauges the health of potential donor organs.

Using light, not surgery, for biopsies by Laura L. Hunt

Only a small number of human lungs available for transplant are accepted by surgeons.

“Thousands of patients die waiting for a suitable organ that can support life, and we have limited means to assess whether a [donor] organ is irreversibly damaged,” says Robert Love, M.D., a professor of surgery at the Medical College of Wisconsin (MCW).

The assessment process relies heavily on how the organs look externally.

The change in the tissue’s metabolism is the key to assessing the extent of injury, Ranji says, and that’s exactly what her technology delivers.

Mahsa Ranji, a UWM assistant professor of electrical engineering, has developed a method that could dramatically increase the number of organs deemed usable for transplants. Called “optical biopsy,” it gives doctors a noninvasive tool that gauges the metabolic health of tissue.“Before now, the only way to see whether tissue is injured is through surgical biopsy,” says Ranji. “The main idea behind optical biopsy is to follow the metabolic state of the tissue through a catheter over time.”

Mahsa Ranji tests her optical biopsy technology on lung tissue of an animal model in this experiment at the Medical College of Wisconsin.

Mahsa Ranji tests her optical biopsy technology on lung tissue of an animal model in this experiment at the Medical College of Wisconsin.

The change in the tissue’s metabolism is the key to assessing the extent of injury, she adds, and that’s exactly what her technology delivers.

“It is important because the gold standard now is a snapshot at the end point of an event,” she says. “You don’t have the story of what happened to the tissue at the beginning or in the middle.”

Ranji’s patented technology works by exciting certain proteins in living tissue that glow when they absorb blue and ultraviolet (UV) light. Since a catheter remains in contact with the tissue, drugs can also be administered while monitoring the efficacy of any treatments.

“We are interested in providing a deeper look at the mitochondria, the energy centers of the cells,” she says.  “The intensity of the glow corresponds to the health of the tissue.”

Doctoral student Zahra Ghanian has been working on a related diagnostic tool created in Ranji’s lab – one that can extract markers of tissue damage on a cellular level.

Ghanian gathers visual biomarkers of the level of oxidative changes in cells – clues that the tissue is injured. Then she writes a computer program that takes all the markers into account in determining the extent of damage.

In a process called segmentation, Ghanian can comb through images of retina cells, for example, to create the required data to use as diagnostic markers of diabetic retinopathy.

“This gives you a picture of cells in the retina, indicating the number, kind and how they are distributed,” says Ghanian. “When the ratio of one kind of cell to another kind rises, it means the disease is progressing. This is one of the earliest signs of diabetic retinopathy that we can quantify.”

The work of Ghanian and Ranji exemplifies the advantage of locating UWM researchers at Innovation Campus in Wauwatosa: It brings biomedical research much closer to the regional medical complex where partnerships like those with Ranji’s lab can help accelerate discovery and support students.

In fact, part of Ranji’s lab will be among five research labs that occupy the new Innovation Accelerator at Innovation Campus when it is completed this spring. (Read about the others at “A new home for innovation.”)

Ranji has partnered on the lung transplant project with Elizabeth Jacobs, M.D., MCW associate dean of research and associate chief of staff for research at the Zablocki VA Medical Center. Testing of the optical biopsy system has already begun with human organs in experiments with Jacobs and Love.

“If we need to do an experiment at MCW that needs animal models, we are right there. These experiments are expensive, time-consuming and involve a lot of people,” Ranji says. “So the proximity will help.”

She believes it will lead to more opportunities to work with medical professionals, allowing graduate students to see firsthand how the instrumentation they build is used on the patient-care side.