Blind Cave Fish Beat Back Diabetes Symptoms That Would Kill People
[Editor's note: This story was updated on Sept. 22, 2017, to state that geneticist Cliff Tabin's remarks were made as part of his scientific talk.]
For months fish that live in dark caves in Mexico go without food. They have gone far longer—millennia—without light, evolving to lose their eyes and skin pigments.
Now researchers have discovered these strange creatures have another oddity. To survive their food-scarce environment, the fish have evolved extreme ways of turning nutrients into energy. These features create symptoms like large blood sugar swings that, in humans, are precursors of type 2 diabetes. But in the fish these changes are adaptations, not a disease. These cave fish lead long and healthy lives.
Understanding how the fish remain healthy in spite of these ominous symptoms may lead to new therapeutic approaches for treating diabetes in people, notes Cliff Tabin, a geneticist at Harvard Medical School. Tabin identified these features and described them last month at a meeting of the Pan-American Society for Evolutionary Developmental Biology in Calgary. And he and his colleagues are beginning to get clues about how cave fish pull off this feat.
In humans and other mammals one of the first signs of type 2 diabetes risk is poor control of blood sugar (glucose). This happens because cells resist insulin, the hormone that signals cells to take in glucose from the bloodstream. If the problems continue, they progress into full-blown diabetes characterized by blood glucose levels of 140 milligrams per deciliter or higher, organ failure, leaky blood vessels, damage Continue reading