Louisiana State University: LSU Mechanical Engineering Professor Studies Tissue-Freezing Processes

Press release from Louisiana State University:

September 8, 2021

BATON ROUGE, LA – For most Americans, four hours equates to half a workday or an afternoon
of binge-watching TV. But for 106,764 women, men, and children waiting for an organ
transplant, those 240 minutes are a matter of life and death.

Four hours is all the time an organ transplant recipient has to fly or drive to where
a new organ awaits and for surgery to begin. Some don’t make it in time, and others
die waiting for a life-changing phone call that never comes.

Wanting to give every organ transplant recipient a greater chance at life, LSU Mechanical
Engineering Professor Ram Devireddy is researching different cooling rates for organs
so that they remain viable longer and could even be frozen and transported across
the world.

“My research is trying to understand how freezing affects biological systems,” he
said. “We currently don’t have measurement methods to figure out what is happening
to tissues when we freeze them fast. This information will tell us how to best store
organs.”

According to Devireddy, the number of organ donors is not the problem; it’s getting
the perfect match to the recipient. Freezing organs would enable a longer time for
transport if an organ is the right match for a recipient more than four hours away.

“That’s the holy grail,” he said. “As engineers, we’re trying to see how best to do
this in a rational matter.”

Tissue damage can occur whether you freeze organs fast or slow. The trick is finding
just the right amount of cooling time that keeps the tissue viable. Most tissue damage
occurs when it’s cooled from -2°C to -40°C in a matter of seconds to minutes. The
optimal approach is to freeze in such a way that the damage is minimized.

“Different organs require different cooling rates,” Devireddy said. “The liver has
similar tissue throughout, whereas the heart has multiple cell types. Each cell is
going to behave slightly different under temperature stress. Imagine 100 kids on a
bus, and each student must travel at a certain speed to reach home safe and sound,
but the bus can only travel at one speed. How do you find a common agreeable speed
to minimize the damage to all students on the bus?”

Devireddy, whose research is funded by a $432,803 grant from the National Institute
of Health, is using a combination of two techniques—one based on microfabricated thermocouples
and another using calorimetry–to closely study tissues under temperature stress.

“Under a microscope, we can control how fast the temperature changes on the glass
and make measurements during freezing of optically transparent cells, but we can’t
do the same thing with tissues because light doesn’t go through tissues, which are
opaque,” he said. “That’s why we are developing new techniques to study fast-freezing
processes in tissues.”

Though Devireddy has years of research left on this topic, he has jumpstarted an idea
that could save many lives and even spur researchers to study other parts, such as
thawing an organ, which is just as problematic as freezing one.

“This research is just one challenge,” he said. “It’s part of a bigger picture.”

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Contact: Libby Haydel

Communications Specialist

ehaydel1@lsu.edu

225-578-4840

This press release was produced by Louisiana State University. The views expressed here are the author’s own.