The study may help explain why roughly 5 percent of women develop diabetes temporarily while pregnant, a condition called gestational diabetes. That condition is a leading cause of birth defects and can predispose the child to develop diabetes later in life.
"The basis of gestational diabetes has been a black box," said Seung Kim, MD, PhD, associate professor of developmental biology and senior author on the study. The results will be published in the Nov. 2 issue of the journal Science.
The protein Kim and his colleagues studied, called menin, was already known to have a role in preventing cancer in the pancreas and other organs. When menin is present it blocks the growth of pancreatic cells and, in that way, prevents cancer.
However, cells of the hormone-producing part of the pancreas, called the islets, need to grow in pregnant women or when people gain weight as a way of providing enough insulin for the burgeoning supply of cells. The increase in pancreas islet cells provides the additional insulin needed for the cells of the body to take up sugar from the blood. After a pregnant woman delivers her child, the pancreatic islets return to their original size.
According to Kim's work in mice, the pancreas accomplishes that adaptive growth by producing less menin during pregnancy. With less of the brake present, the pancreatic islet cells can divide, and this growth provides the additional insulin. Within a week after delivery the menin levels in the mice were back up to normal and the pancreatic islets began shrinking to their original size.
When Kim and postdoctoral scholar Satyajit Karnik, PhD, first author of the study, created mice that produce too much menin, the islets couldn't grow sufficiently during pregnancy and the mice ended up with gestational diabetes.
"This suggests that there is an internal code for controlling pancreatic islet growth, a code we intend to crack," Kim said. That code appears to be regulated partly by the level of menin.
Kim's group also showed that a natural way of regulating the amount of menin present in the pancreas is through a hormone called prolactin, which is abundant in pregnant women. Other researchers had previously shown that prolactin during pregnancy stimulates the islet cells to start dividing, but how it accomplished this stimulation was unclear.
Kim and Karnik suspected menin might be the link other researchers had been looking for. To test that idea, they gave prolactin to nonpregnant mice. As predicted, menin levels dropped and the pancreas increased in size, mimicking what is seen during pregnancy.
Kim said that although most of this research relates to menin regulation during pregnancy, similar forces may be at work in obese adults with diabetes. He and Karnik found that obese mice have less menin in the pancreas than mice at a normal weight. That finding suggests that menin may have a central role in obesity-related diabetes as well.
Kim said prolactin may be just one way of regulating menin levels and as a result regulating pancreatic growth. Other hormones may be involved in increasing or decreasing menin in nonpregnant adults.
Understanding the mechanisms of regulating menin should lead to new ways of growing islets for transplantation into people with type-1 diabetes and could lead to new treatments for diabetes in pregnant women or obese adults, Kim said.
Gestational diabetes, which is on the rise nationwide, is becoming more recognized as a significant risk to mothers and their babies. Sen. Hillary Rodham Clinton, D-NY, recently cosponsored a bill aimed at devoting more funding to understanding, preventing and treating the disease.
Amy Adams | EurekAlert!
Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society
127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Power and Electrical Engineering
18.01.2017 | Materials Sciences
18.01.2017 | Life Sciences