Hurricane Maria hit Puerto Rico in 2017 causing over $100 billion in damage, killing over 3,000 people and traumatizing many more. But that was not all: it also accelerated the aging process of rhesus macaque monkeys living in the area.
A new study of these macaques found that the trauma aged the monkeys by an average of 2 years, which is about 7 to 8 years of the human lifespan. “Our results suggest that the experience of an extreme hurricane is associated with alterations in immune cell gene regulation, similar to aging, potentially accelerating some aspects of the aging process,” the authors wrote.
“While everyone ages, we do not all age at the same rate, and our lived experiences, both negative and positive, can alter this rate of aging. A negative life experience, surviving an extreme event, can lead to chronic inflammation and the early onset of certain age-related diseases, such as heart disease,” said Noah Snyder-Mackler of Arizona State University, co-author of a new study published in Proceedings of the National Academy of Sciences.
Researchers seek to understand the long-term psychological and physical effects of extreme weather events on people by studying macaques, which are closely related and can reveal how humans react.
Rhesus macaques were introduced to the island of Cayo Santiago, less than a mile from Puerto Rico, in 1938. Now naturalized, the 1,800 free-roaming monkeys have long been studied by scientists to sift through their links to humans, including their health and aging process.
Although disease development may differ even among people of the same chronological age, those who have had extremely adverse experiences are at greater risk of developing heart disease that is more common in older age. It is not known how traumatic experiences promote disease.
The authors believe that extreme adversity effectively ages the body. People can differ in their biological age, as measured by molecular landmarks in our immune system, genes, and physiology.
“From this study, we measured molecular changes associated with aging, including disruptions in protein folding genes, greater expression of inflammatory immune cell marker genes, and older biological aging,” the study said. study co-author Marina Watowich.
“Our results suggest that differences in immune cell gene expression in individuals exposed to an extreme natural disaster were in many ways similar to the effects of the natural aging process,” Snyder-Mackler said. “We also observed evidence of accelerated biological aging in samples collected after animals experienced Hurricane Maria.”
The researchers found evidence in the macaques’ immune cells that the aging of the immune system had accelerated. “On average, the monkeys that experienced the hurricane had immune gene expression profiles that aged an additional 2 years, or about 7-8 years of [a] human lifespan,” Watowich said.
Severe weather events can harm the health of those who survive them, they say. Immune cell gene regulation may explain how natural disasters drive the onset and progression of age-related diseases, Watowich said.
In blood samples, the researchers found that 4% of monkey genes expressed in immune cells had been altered by the storm. In addition, there was higher expression of genes involved in inflammation, while genes expressing protein translation and protein folding/folding, adaptive immune response, and T cells were also affected.
Heat shock genes, essential for making proteins in cells, were also deleted. Some saw their activity reduced by two after the hurricane. These are also implicated in Alzheimer’s disease and cardiovascular disease.
The researchers also found a distinct link between trauma and gene expression in which the effect of the storm resembled the effect of an aged immune system. Snyder-Mackler noted that genes involved in inflammation changed in macaques that survived the storm, which then looked like older apes.
“Together, this may imply more inflammatory activity in animals after [a] storm, similar to what we see in older people,” Snyder-Mackler said.
Not all monkeys are alike, researchers say, and some age faster than others. The scientists concluded that environmental factors influenced the results. Macaques resemble humans in behavior and physiology. As with people, mutual support is essential for survival. Monkeys with better social support were more likely to survive with less trauma than those without, the researchers hypothesized. This is a possibility they will explore further.
The researchers hope their study will lead to a better understanding of aging and better mitigation of the effects of natural disasters.
Edited by Siân Speakman and Kristen Butler