Oxygen deficiency increases mouse lifespan by 50 percent, will it work in humans?
Oxygen supports almost all life on Earth but for the first time, a study from the researchers at Harvard University’s Mootha Lab, and Massachusetts General Hospital (MGH) suggests that oxygen deficiency (hypoxia) can increase the lifespan of mammals.
“It has been known for about 20 years that chronic continuous hypoxia extends the time to senescence in cultured cells and extends the lifespan in yeast, worms, and fruit flies. Our study is the first to test oxygen restriction in a mammalian model of aging in the laboratory,” Robert Rogers, lead researcher and a physician at MGH, told Interesting Engineering (IE).
The study authors tested a mouse model in oxygen-deficient conditions similar to those found at Mount Everest base camp (at an altitude of 5,000 meters). They noticed that hypoxia increased the lifespan of the animal by a whopping 50 percent.
So can hypoxia also increase the human lifespan?
During the study, the researchers performed an experiment on a mouse model that lacked the Ercc1 protein. This is a useful model of aging because it has a shortened lifespan of less than six months. It is due to the Ercc1 deficiency, it accumulates physiological and biochemical features of aging across all organs at an accelerated pace.
They kept the mouse in an environment with only 11 percent oxygen and compared its lifespan with mice that lived in normal conditions (21 percent oxygen). Surprisingly, the animal model in the low-oxygen atmosphere managed to stay alive for 23.6 weeks, but the average lifespan of mice living in normal conditions turned out to be only 15.7 weeks.
Hypoxia enabled the mouse model to live 50 percent longer. When asked if the technique could also work in humans, Rogers argued that it will be too early to predict if oxygen restriction could increase lifespan in humans and other mammals. This is because the molecular mechanism by which hypoxia extended the lifespan in the mouse is still unknown.
Hypoxia-linked anti-aging
Interestingly, apart from the current study, there are several past research works that suggest that living in environments where there is a lower oxygen concentration might increase the median lifespan and reduce the burden of age-related diseases in humans.
For instance, “an experiment from the 1960s and 1970s in which soldiers of the Indian Army were assigned to serve 3 years at very high altitudes (> 3 miles) and their incidence of the common age-related diseases like diabetes, hypertension, and heart disease were much lower than their similar comrades serving at sea level,” said Rogers.
Another solid example that hints at hypoxia-associated anti-aging is the mole rat. It is the longest-living rodent known for its ability to resist age-related disorders. Interestingly, mole rats inhabit and spend most of their time in burrows having hypoxic conditions.
The researchers suggest that although the abovementioned examples indicate a possible link between hypoxia and increased lifespan, there is no evidence that confirms this connection.
Oxygen restriction may analogously operate via a multitude of mechanisms that impact many cellular processes and systemic physiology. According to the study authors, it is important to first understand these mechanisms before associating hypoxia and anti-aging.
Rogers told IE, “It will take many studies to fully define the potential uses of oxygen restriction in wildtype aging and to understand the molecular mechanisms through which it might be beneficial. We view this initial report as laying the foundation for this important line of future research.”
The study is published in the journal PLoS Biology.