Dolphins can help understand human disease

Dolphins are the first natural model for study human diabetes, opening the possibility of finding treatment against the disease responsible for 5% of annual deaths worldwide.

"Dolphins, like humans, are mammals and their diet consists mostly of fish and seafood we consume," said Carolyn Sotka from agency National Oceanic and Atmospheric Administration (NOAA) at the annual conference of the American Association for the Advancement of Science (AAAS) held from February 18 to 22 in San Diego (California).

These whales are constantly exposed to environmental threats in the ocean as some highly toxic algae that produces domoic acid or pollutants such as PCBs (polychlorinated biphenyls), banned in the U.S. since the 70s.

The similarities between dolphins and humans make these animal "ecological and physiological sentinels, that warn us of health risks give us insights into how we can improve our health," the specialist says.

Dolphins are thus the first natural model for study of human diabetes, opening the possibility for discovery of treatments against the disease responsible for 5% of deaths worldwide per year, according to a study.

This research reveals that bottlenose dolphins, the species most known, may at any time get into a physiological state resembling diabetes.

This mechanism probably results from the diet of these whales very rich in protein and low in carbohydrates.

"As humans consume food rich in proteins to control their diabetes, the dolphins seem to have developed a condition similar to diabetes to help maintain a diet rich in proteins," says Stephanie Venn-Watson, veterinary doctor, Director of Research clinics in the National Marine Mammal Foundation (NMMF).

"The fact that humans and dolphins have both big brain requiring high levels of glucose in the blood could explain why two different species have evolved physiological mechanism similar to metabolize sugar," she says. The researcher notes that the dolphin genome has been sequenced for comparisons with the human genome.

Other evidence collected during this study indicate that dolphins may also have chronic disease similar to humans related to diabetes such as insulin resistance with hemochromatosis (excessive iron levels in the blood) or kidney calcification.

Finally scientists believe that humans have developed a resistance to insulin during the last glacial period to maintain a minimum level of glucose in the blood.

Similarly, the dolphins have acquired the same resistance to insulin when they went to live in the ocean about 55 million years ago.

A further research of the University of Florida filed Thursday in San Diego shows that dolphins are infected as human papillomavirus that does not seem to cause them cancer of the cervix as in humans.

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