Aging leaves no one behind, but humans all experience the process differently, based on genetics and lifestyle factors.
Conversely, dolphins used by the U.S. Navy exist in a fairly uniform set of conditions – diet and habitat are roughly the same for all individuals. Because these aquatic mammals experience aging in a manner similar to humans, marine dolphins were recently selected as the subjects of a new long-term study. The distant future goal: Slow down the process of human aging.
The results of this study were published in the journal on Monday Procedures of the National Academy of Sciences.
In dolphins, four key traits demonstrate how graying appears in the blood, the research team reports. Scientists took blood samples from 144 dolphins over 25 years at home to markers relevant to human health. The findings demonstrate the difference between slow and accelerated aging between individuals in the same population.
Lead study author Stephanie Venn-Watson is the co-founder and CEO of life sciences company Epitracker.
“While it has long been believed that some people age faster than others, it has been difficult to prove that people are actually older at different rates,” says Venn-Watson Inverse.
Venn-Watson and colleagues identified four biomarkers in dolphin blood that help measure the rate of aging:
- Hemoglobin – An iron-containing protein that transports oxygen into red blood cells; decreases with age
- The lymphocytes – immune cells; decrease with age
- Platelets – Cell fragments involved in blood clotting
- Alkaline phosphatase – An enzyme used to detect liver and bone disease
“Based on these indexes, we were able to confirm the presence of both slow and accelerated grazing dolphins,” says Venn-Watson. In other words, they measure what a steep versus a slow graying process looks like.
Hemoglobin and lymphocytes, for example, decrease with age, Venn-Watson explains. Taken together, this puts older dolphins (and humans) at greater risk for anemia and serious infections. Dolphins that earn faster pose an even greater risk.
The finding “supports that significant, non-environmental drivers of aging can be identified, and thus, can be addressed even to bear aging. ”
With humans and wild dolphins, the aging process is slowed down by environmental or lifestyle factors. In humans, this includes socioeconomic status and chronic medication. In contrast, U.S. Navy dolphins, which are trained for missions such as retrieving equipment and detecting underwater mines, live in similar conditions. This enabled researchers to isolate aging patterns without environmental conditions.
“Importantly, we were able to clearly distinguish slow and accelerated aging of dolphins, despite the fact that all dolphins in the population shared the same diet, health care and oceanic environment,” says Venn-Watson. The finding “supports that significant, non-environmental drivers of aging can be identified, and thus may be aimed at delaying aging itself.”
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That idea could inform human medicine in the future, and potentially the development of therapies that slow down the process of human aging.
Most aging research in animals includes those with short lifespans, such as worms, flies and mice. By studying dolphins, Venn-Watson says she hopes to learn how long-lived animals, like humans, reach their older ages in the first place – and “how can we use these mechanisms to help humans and dolphins live longer and healthier to live. ”
Dolphins are a particularly useful model for studying human aging because they can be affected by aging-related conditions such as high cholesterol, chronic inflammation, and even Alzheimer’s disease.
“These agreements support that dolphins and humans share similar mechanisms with aging,” says Venn-Watson.
Now, with this study, scientists have evidence of slow and accelerated aging in dolphins. This could ultimately help researchers to direct and slow down the aging process in humans.
“We hope our study can help physicians and longevity researchers prioritize clinically relevant indices in older people, including declining hemoglobin and lymphocytes,” says Venn-Watson, “to not only prevent and treat anemia and reduce immunity, but eventually to help delay aggravation as well. “
Abstract: Although it is thought that humans age at different rates, a lack of robust longitudinal human studies with consensus biomarkers intended to capture aging rates has a bearing on the extent to which individuals differ in their rate of aging. Because bottlenose mammalian dolphins are long-lived animals that develop comorbidities of aging similar to humans, we analyzed data from a well-controlled, 25-y longitudinal cohort of 144 U.S. marine dolphins living in the same oceanic environment are. Our analysis focused on 44 clinically relevant hematological and clinical chemical measures included during routine blood draws during the life periods of the dolphins. Using stepwise regression and general linear models that include correlations between measures obtained on individual dolphins, we demonstrate that dolphins, in a manner similar to humans, display independent and linear age-related decreases in four of these measures: hemoglobin, alkaline phosphatase, platelets, and lymphocytes. Using linear regressions and covariance analyzes with post hoc Tukey – Kramer tests to compare slopes (ie, linear age-related rates) of our four biomarkers with aging rates among 34 individual dolphins that range from 10 y to 40 y old, we identify slow and accelerated agers and distinct subgroups that were more or less likely to develop anemia and lymphopenia. This study successfully documents differences in aging over the lives of individuals with long lives in a controlled environment. Our study suggests that non-environmental factors influencing allergy biomarkers, including declining hemoglobin and anemia, may be targeted to slow the effects of aging in a compelling model of human biology.
