Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Poor prenatal nutrition permanently damages function of insulin-producing cells in the pancreas

25.02.2005


Scientists at Joslin Diabetes Center have discovered one reason why infants with low birth weight have a high potential of developing type 2 diabetes later in life. In studies of mice, the researchers found that poor prenatal nutrition impairs the pancreas’s ability to later secrete enough insulin in response to blood glucose.



"The bottom line is that if you don’t have delivery of enough nutrients from the mother to the baby, the baby’s pancreatic cells will be programmed abnormally," said principal investigator Mary-Elizabeth Patti, M.D., Assistant Investigator in Joslin’s Research Section on Cellular and Molecular Physiology and Assistant Professor of Medicine at Harvard Medical School. "The effect doesn’t show up until later on -- usually not until adolescence or adulthood.

"Many people believe we don’t have much of a prenatal nourishment problem in the United States," she added. "But poor nutrition of a developing baby can occur in many ways other than inadequate nutrition of the mother. It also can occur with abnormal development of the placenta and its blood vessels, or high blood pressure, which damages vessels." In addition, many other factors can result in intrauterine growth restriction and low birth weight.


The Joslin study, published in the March edition of Diabetes, reinforces what scientists have known from previous studies in humans: Infants with low birth weight -- typically defined as under five and one-half pounds -- have a higher risk for developing type 2 diabetes.

To understand the reason, the researchers designed a series of experiments. Using ordinary mice that were not inbred or genetically altered in any way, they mated females with males, dating the day of their pregnancy, which lasts three weeks. They separated the mothers into two groups. The control group ate as much chow as they wanted during the entire pregnancy. The other group also was fully nourished during the first two weeks but undernourished during the third week, restricted to only half the amount. It had a dramatic effect. At birth, their babies weighed 23 percent less than the control group.

After delivery, all babies nursed and all mothers ate a full diet. "By the time the babies were weaned, at three weeks, the low-birth-weight group had caught up with the others, something we see in human babies too," said Dr. Patti. "They looked and acted the same. There was nothing outwardly different about them." The two groups of offspring ate the same chow diet, maintained a similar weight, and neither group was allowed to become overweight, eliminating this common risk factor for diabetes. The only difference was that the mothers had been fed differently during the final week.

As the young mice matured, the researchers tested their blood glucose (sugar) after meals. At age 2 months, the results were similar between the two groups. But over time, differences began to unfold. When 4 months old (comparable to human adolescence), the low-birth-weight babies began showing higher levels of blood glucose. "By 6 months, these levels had spiked abnormally, to 500 mg/dl -- the equivalent of serious, full-blown diabetes in humans," Dr. Patti said.

In type 1 diabetes, the pancreas cannot make the hormone insulin at all; about 1 million Americans must control this form by taking insulin injections. In type 2 -- a disorder affecting an estimated 18 million Americans -- the pancreas doesn’t make enough insulin or the body’s cells develop a resistance to its effect. Without insulin, glucose cannot get into cells to provide energy.

Normally, insulin levels rise or drop in response to glucose levels, keeping everything in balance. But diabetes is a complex metabolic disorder with numerous players such as high levels of blood glucose, cholesterol and other lipids. "The challenge is to figure out which factors are a primary cause of diabetes and which are a consequence, said Dr. Patti. "In our study, we needed to find out what was happening in these mice, before they got the problem."

Their insulin levels provided a clue. In the prenatally undernourished mice, the insulin secretion stayed about the same, regardless of the glucose level in the bloodstream. "That surprised us," Dr. Patti said. "The problem was not insulin resistance. It had something to do with insulin secretion." By contrast, babies who are born overweight (greater than 8 pounds) have higher risk of insulin resistance, not a secretion problem. Something different was happening in the experiment’s low-birth-weight mice.

Did prenatal undernourishment cause the pancreas to not fully develop? The researchers found no difference in pancreas size or numbers of pancreatic beta cells, which produce insulin.

But cultures of the beta cells revealed the answer: the undernourished mice had an abnormal way of responding to glucose. "They were somehow ’programmed’ to secrete a limited amount of insulin later in life, no matter what signal they got from glucose," Dr. Patti said. "The impairment was permanent. It couldn’t be corrected even when the body caught up to normal weight."

Because studies of mice generally are good predictors of human biology, the Joslin study has important implications. "People and their doctors need to understand that prenatal undernourishment makes a person permanently at higher risk for developing diabetes, so prenatal care is important," Dr. Patti said. "Moreover, if someone was born with low weight, they need to pay special attention to prevention tactics, including exercise and weight control to minimize insulin resistance -- the other major factor involved in triggering type 2 diabetes.

"In particular, someone who was a low-birth-weight baby can compound the risk of developing diabetes by becoming overweight," she added. "The stage is set in two ways: low insulin production coupled with resistance to insulin -- a double whammy."

Other researchers involved in the Joslin study included co-authors Jose C. Jimenez-Chillaron, Ph.D., Marcelino Hernandez-Valencia, M.D.; also Carolyn Reamer, Simon Fisher, M.D., Ph.D., Allison Joszi, Ph.D., Michael Hirshman, Aysin Oge, M.D., Shana Walrond, Roberta Przybyla, Carol N. Boozer, D.Sc., of St. Luke’s-Roosevelt Hospital Center in New York, and Laurie Goodyear, Ph.D., head of the Section on Metabolism at Joslin. The research was funded by the American Diabetes Association and the Adler Foundation.

Marjorie Dwyer | EurekAlert!
Further information:
http://www.joslin.harvard.edu

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>