The findings are published in the Feb. 24 online edition of The FASEB Journal, a publication of the Federation of American Societies of Experimental Biology.
Corresponding study author, Jane J. Kim is an assistant professor in the UCSD Department of Pediatrics and a member of the Pediatric Diabetes Research Center and Rady Children's Hospital-San Diego, a research and teaching affiliate of the UCSD School of Medicine. Kim said the findings represent the first documented evidence linking the sugar production to insulin and glucose metabolism problems associated with diabetes.
"It opens up a new perspective in understanding the causes of diabetes," said Kim. "Given the global epidemic of obesity and diabetes, we think that these findings suggest that evolutionary changes may have influenced our metabolism and perhaps increased our risk of the disease."
Type 2 diabetes is caused by both genetic and environmental factors, such as a fatty diet and lack of exercise, that result in progressively dysfunctional pancreatic beta cells, elevated blood sugar levels due to insulin resistance and eventual health complications, sometimes fatally so. Diabetes is an expanding problem, nationally and globally. In the United States, more than 25 million adults and children – almost nine percent of the population – have diabetes, according to the American Diabetes Association. Another 79 million Americans are estimated to be prediabetic. Worldwide, roughly 285 million people are believed to have the disease.
Sialic acids are sugar molecules found on the surfaces of all animal cells, where they act as vital contact points for interaction with other cells and with their surrounding environment. Virtually all mammals produce two types: N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc).
Humans are the exception. For reasons lost in the mists of evolution, a mutation in a gene called CMAH occurred 2 to 3 million years ago, inactivating an enzyme in humans that catalyzes production of Neu5Gc by adding a single oxygen atom to Neu5Ac.
Researchers compared two groups of mice: one with a functional CMAH gene, the other with an altered CMAH gene similar to the human mutation. Both groups of mice were fed a high-fat diet. Mice in both groups became obese and developed insulin resistance. However, only mice with the CMAH gene mutation experienced pancreatic beta cell failure – the cells that make and release insulin, a hormone that controls blood sugar levels.
Kim said the findings help refine understanding of why obese humans appear to be particularly vulnerable to type 2 diabetes, and also suggest that current animal models used to study diabetes may not accurately mirror the human condition. In clinical terms, she said further research to determine how sialic acid composition affects pancreatic beta cell function may reveal new strategies to preserve the cells, improve insulin production and prevent diabetes.
Co-authors of the study are Sarah Kavaler and Alice Jih, UCSD Department of Pediatrics and Rady Children's Hospital-San Diego; Hidetaka Morinaga and WuQuiang Fan, UCSD Department of Medicine; Maria Hedlund and Ajit Varki, UCSD departments of Medicine, Cellular and Molecular Medicine and UCSD Glycobiology Research and Training Center.
Funding support was provided by the National Institutes of Health.
Scott LaFee | EurekAlert!
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences