Giancarlo Lopez-Martinez, a North Dakota State research assistant professor of biological science, presented his research on hormesis and its potential benefits for Parkinson’s and Alzheimer’s patients at NDSU Friday, Nov. 16.
Lopez-Martinez, who studies the effects of environmental stress on animals, is a comparative stress physiologist. The title of his presentation was “Hormesis: When Environmental Stress Improves Organismal Performance and Fitness.”
According to the U.S. National Library of Medicine and the National Institutes of Health, “Hormesis refers to a biphasic dose-response to an environmental agent characterized by a low dose stimulation or beneficial effect and a high dose inhibitory or toxic effect.”
Lopez-Martinez began his research first with an idea in Antarctica thinking about environmental stress. Environmental stress is any biotic or abiotic change that results in negative consequences toward performance or fitness, according to Lopez-Martinez.
“I started to think stress is good, for a lack of better words,” Lopez-Martinez said. ‘It embodies the evolutionary spirit.”
Lopez-Martinez began his work studying environmental stress and its effects in development, lifespan, senescence and reproductive output. He studies environmental stresses like temperature (high and low), water (overhydration and dehydration), changes in radiation (ultraviolet, gamma and X-rays) and changes in oxidative stress.
“Oxidative stress is just an imbalance,” Lopez-Martinez said. “However, there are two imbalances: an imbalance with a lot of ROS (reaction oxygen species), but the other type of imbalance is just the opposite, and that is what got me thinking that stress is good.”
Oxidized stress occurs from ROS formation, which refers to incomplete and partial oxidation of oxygen. The oxidative imbalance is between ROS and antioxidants negatively impacts organismal performance when ROS is disproportionally generated during periods of stress, according to Lopez-Martinez.
“My interest is what is the positive role in oxidative stress,” Lopez-Martinez said. “To induce oxidative stress, I used radiation.”
The radiation strips electrons from gaseous oxygen, which results in direct disruption of biomolecules, such as severe bond breakage damage and death, and generation of free radicals, such as ROS, which also leads to chronic damage and death.
“But if you lower your amount of radiation and make it so tiny when you’re actually not breaking any bonds: no damage in DNA, no damage in sugar and no damage in lipids,” Lopez-Martinez said.
What Lopez-Martinez and his team did for their experiment was take male flies, radiated half of them and put both the radiated and non-radiated flies in a container. Next, they placed female flies in the same container and recorded the number of male flies with and without radiation that the female flies mated with.
“About 75 percent of the time the females picked the flies that were not radiated,” Lopez-Martinez said. “(The female fly) knows that the radiated males are poor quality, and that’s because animals have this way of signaling and presenting that they have good genes.”
They concluded from this experiment that mating success is decreased by oxidative stress. Furthermore, they investigated how to use hormesis to boost performance in flies.
“Hormesis is the term we give to biphasic response,” Lopez-Martinez said. “The biphasic response is detrimental at high doses, but beneficial at low doses.”
Lopez-Martinez then investigated the cross tolerance of oxidative and radiative stress. He then decided to focus on hypoxia-reperfusion response.
Again working with flies, after one hour of radiation and no oxygen, the flies survived. What they found was hormesis prevents damage and improves performance, and X-ray hormesis has translational to therapy potential for Parkinson’s and Alzheimer’s disease.