The findings shed light on how cholesterol is transported through the cells of the body and suggest a possible therapeutic target for Niemann-Pick type C disease (NP-C), an inherited neurodegenerative disorder characterized by abnormally high cholesterol levels in every organ.
“What we’ve shown is that very quickly after administration of this compound, the huge pool of cholesterol that has just been accumulating in the cells is suddenly released and metabolized normally,” said Dr. John Dietschy, professor of internal medicine at UT Southwestern and senior author of the study appearing online this week and in an upcoming issue of the Proceedings of the National Academy of Sciences. “With just one dose, you excrete a large portion of this pool of cholesterol.”
Cholesterol in the body comes from dietary sources and is also made by the body itself. It is essential for many biological processes, including the construction and maintenance of cell membranes. Cholesterol normally is transported through cells and is excreted by the body.
People with Niemann-Pick type C have a genetic mutation that causes excessive amounts of cholesterol to accumulate in compartments within cells called lysosomes. This cholesterol accumulation leads to liver disease, neurodegeneration and dementia. There is no specific level at which cholesterol levels become abnormal, but the vast majority of children diagnosed with NP-C die before they are 20 years old and many before age 10. Late onset of neurological symptoms such as clumsiness, mild retardation and delayed development of fine motor skills can lead to longer life spans, but few people diagnosed with NP-C reach age 40.
In the current research, researchers injected a single dose of a cholesterol-binding agent known as CYCLO into 7-day-old mice with the Niemann-Pick mutation. Shortly after administration, the mice that received CYCLO began to process cholesterol just as their healthy counterparts did. After 49 days, the mice treated with a single injection continued to show substantially lower tissue cholesterol levels than the untreated mice, as well as improved liver function and decreased eurodegeneration.
Dr. Dietschy, who has been studying cholesterol metabolism for nearly 50 years, cautioned that the findings in no way represent a Niemann-Pick disease cure.
“The key idea is that we appear to have overcome the transport defect in the lysosome that is brought about by the genetic defect or mutation,” Dr. Dietschy said. “We do not yet understand what is happening at the molecular level, but it is clear that this compound somehow overcomes the genetic defect that causes individuals to accumulate cholesterol.”
The next step in Dr. Dietschy’s investigation is to determine the concentration of CYCLO needed to trigger the cholesterol’s release. Researchers also hope to determine in animals the additional lifespan CYCLO administration provides, as well as how long the drug’s affects lasts.
“By treating at seven days, we eliminated approximately one-third of the accumulated cholesterol almost immediately,” Dr. Dietschy said. “Now we want to see what happens if we give it every week. Can we maintain low cholesterol levels? That’s what we’re looking at now.”
Other UT Southwestern researchers involved in the research were Dr. Benny Liu, lead author of the study and postdoctoral researcher in internal medicine; Dr. Stephen Turley, professor of internal medicine; Dr. Dennis Burns, professor of pathology; Anna Miller, student research assistant; and Dr. Joyce Repa, assistant professor of physiology.
The work was funded by the U.S. Public Health Service, the Harry S. Moss Heart Trust, the Ara Parseghian Medical Research Foundation and the Dana’s Angels Research Trust.
Visit http://www.utsouthwestern.org/digestive to learn more about clinical services in digestive disorders, including liver disease, at UT Southwestern. Visit http://www.utsouthwestern.org/pediatrics to learn more about UT Southwestern’s pediatrics clinical services.
Dr. John Dietschy -- http://www.utsouthwestern.edu/findfac/professional/0,2356,11822,00.html
Kristen Holland Shear | Newswise Science News
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy