A new study reveals that certain bat species can survive and thrive with blood sugar levels that would be fatal to humans. This discovery could open new avenues for understanding and treating diabetes.
Researchers from the Stowers Institute for Medical Research have uncovered remarkable adaptations in Neotropical leaf-nosed bats that allow them to process sugar in ways never before seen in mammals. The study, published in Nature Ecology and Evolution on August 28, 2024, reports the highest naturally occurring blood sugar concentrations ever observed in mammals.
Jasmin Camacho, Ph.D., co-first author of the study, states, “Our study reports blood sugar levels that are the highest we have ever seen in nature—what would be lethal, coma-inducing levels for mammals, but not for bats. We are seeing a new trait we didn’t know was possible.”
Sugar-Loving Bats: A Natural Experiment in Evolution
Over the past 30 million years, Neotropical leaf-nosed bats have evolved from insect-eaters to species with diverse diets including fruits, nectar, and even blood. This dietary diversity makes them an ideal subject for studying how animals adapt to different food sources.
The research team conducted fieldwork in Central America, South America, and the Caribbean, performing glucose tolerance tests on nearly 200 wild-caught bats across 29 species. They measured blood sugar concentrations after feeding the bats one of three types of sugars associated with different diets.
“We saw various ways sugar is assimilated—absorbed, stored and used in the body—and how this process has become specialized due to different diets,” explained Andrea Bernal-Rivera, co-first author of the study.
Extreme Adaptations for Sugar Processing
The study revealed a spectrum of adaptations for maintaining blood sugar levels, known as glucose homeostasis. These adaptations range from changes in intestinal anatomy to genetic alterations in proteins that transport sugar from blood to cells.
Fruit bats, for instance, have fine-tuned their insulin signaling pathway to lower blood sugar efficiently. Nectar bats, on the other hand, can tolerate extremely high blood glucose levels, similar to those seen in uncontrolled diabetes in humans. Surprisingly, their glucose regulation doesn’t seem to depend on insulin.
While the exact mechanism nectar bats use to manage glucose is still under investigation, the researchers found some intriguing clues:
- Bats with sugar-rich diets have longer intestines and intestinal cells with greater surface areas for nutrient absorption.
- Nectar bats continuously express a gene responsible for sugar transport, a trait also observed in hummingbirds.
Why It Matters
This research has significant implications for human health, particularly in understanding and potentially treating diabetes. By studying how bats have evolved to handle extreme blood sugar levels, scientists may uncover new strategies for managing glucose in humans.
Nadav Ahituv, Ph.D., a bioengineering and genetics professor at the University of California, San Francisco, who was not involved in the study, commented on its potential impact: “The datasets will fuel future research that aims to differentiate mammalian dietary differences and could progress the development of novel therapeutics for a variety of metabolic diseases in humans.”
Future Directions and Challenges
While this study provides valuable insights, several questions remain:
- How exactly do nectar bats regulate their blood sugar without relying on insulin?
- Can the adaptations observed in bats be safely replicated or mimicked in humans?
- What are the long-term effects of consistently high blood sugar levels on bat physiology?
As researchers continue to explore these questions, they may unlock new approaches to treating diabetes and other metabolic disorders. However, translating findings from bats to humans will require extensive further research and careful consideration of the ethical implications.
