How data from Navy dolphins are filling the information gap
Popularized by television and film, humans have long had an affinity toward dolphins. The sleek, intelligent mammals are fan favorites at water shows as they flip, tumble and pirouette their way to applause. Theatrics aside, TGen Distinguished Professor Dr. Nicholas Schork finds dolphins — in particular bottlenose dolphins — interesting for what they may offer scientifically toward understanding the biology of aging.
The results of a recent study by Dr. Schork, in collaboration with colleagues at Epitracker (a private research firm) and the United States Navy, lead to a publication in the Proceedings of the National Academy of Sciences that could help scientists develop a more in-depth knowledge of, and perhaps delay, the aging process and decrease chronic conditions associated with growing old.
Dolphins are one of the very few natural animal models for studying certain aspects of human physiology that cause or result from disease or injury. Dolphins can, for example, exhibit signs consistent with nonalcoholic fatty liver disease (which is present in as many as 25% of the population globally) and Alzheimer’s disease, the most common form of neurodegenerative disease in humans.
To reach their conclusions, the scientists pored over 25 years’ worth of data collected by the U.S. Navy on 144 dolphins — known as Navy dolphins — that received meticulous care throughout their lives; having undergone dozens of precision tests on a strict schedule to help ensure their health and wellbeing. These health data included 44 clinically relevant measurements on 5,889 biological routine samples collected throughout the dolphins’ lifetimes.
“The results from the dolphin population analysis are directly translatable into human biology and will now empower us to identify how aging rates vary in humans and — someday — let us all age gracefully,” said Dr. Schork, who directs TGen’s Quantitative Medicine & Systems Biology Division and serves as Scientific Director for the National Institute on Aging’s Longevity Consortium.
It has long been believed that there are factors influencing why some humans and mammals age faster than others, and identifying those factors requires a data set that has been difficult to develop in species closely related to humans — one that is sufficiently large, robust, longitudinal in nature, and collected in a well-controlled population over lifetimes. The nature of the Navy dolphins’ shared environment created a perfect setting to generate unparalleled longitudinal health data using easily measured biomarkers that identified slow and accelerated aging in dolphins.
“The study highlights how biological differences between dolphins, living in the same natural ocean environment and receiving routine medical examinations under the care of the U.S. Navy, may inform new approaches to slow processes associated with human aging,” said Dr. Schork.
The scientists theorized that because the Navy dolphins all share the same aquatic environment, food and healthcare, other factors must exist that explain why some Navy dolphins live longer than others. They found answers through biomarkers, biological beacons that serve as an indicator of a certain disease state or some other physiological condition of an organism.
Navy dolphins, which on average live 50 percent longer than wild dolphins, consumed a controlled and well-maintained fish diet and received ongoing health monitoring and medical care.
Dr. Schork and colleagues tapped into this wealth of data, using dolphin biomarkers to identify trends that are likely to be very similar in people, in hopes of finding new ways to slow the degradative processes associated with aging.
The scientists identified four key biomarkers associated with accelerated aging. Some dolphins exhibited declines in these biomarkers as they aged, while others exhibited none. Two of these biomarkers, which already are used in assessing older people, decreased linearly with age: hemoglobin, used to detect anemia; and lymphocytes, used to detect immunosenescence, or weakened immunity.
Importantly, while some dolphins had declines in these clinical biomarkers as they aged, including declines leading to clinical anemia and immunosenescence, others had no declines during the same aging timeframe.
“Amazingly, this work all started with the sole intent of continually improving the health and welfare of dolphins,” said Stephanie Venn-Watson, D.V.M., M.P.H., co-founder and CEO of Epitracker and Seraphina Therapeutics. “The fact that our work is resulting in groundbreaking approaches to delay aging and improve health for both dolphins and humans is a dream come true.”