Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Simulated Mars Mission Reveals Body’s Sodium Rhythms

09.01.2013
Clinical pharmacologist Jens Titze, M.D., knew he had a one-of-a-kind scientific opportunity: the Russians were going to simulate a flight to Mars, and he was invited to study the participating cosmonauts.

Titze, now an associate professor of Medicine at Vanderbilt University, wanted to explore long-term sodium balance in humans. He didn’t believe the textbook view – that the salt we eat is rapidly excreted in urine to maintain relatively constant body sodium levels. The “Mars500” simulation gave him the chance to keep salt intake constant and monitor urine sodium levels in humans over a long period of time.

Now, in the Jan. 8 issue of Cell Metabolism, Titze and his colleagues report that – in contrast to the prevailing dogma – sodium levels fluctuate rhythmically with 7-day and monthly cycles. The findings, which demonstrate that sodium is stored in the body, have implications for blood pressure control, hypertension and salt-associated cardiovascular risk.

Titze’s interest in sodium balance was sparked by human space flight simulation studies he conducted in the 1990s that showed rhythmic variations in sodium urine excretion.

“It was so clear to me that sodium must be stored in the body, but no one wanted to hear about that because it was so different from the textbook view,” he said.

He and his team persisted with animal studies and demonstrated that the skin stores sodium and that the immune system regulates sodium release from the skin.

In 2005, planning began for Mars500 – a collaboration between Russia, the European Union and China to prepare for manned spaceflight to Mars. Mars500 was conducted at a research facility in Moscow between 2007 and 2011 in three phases: a 15-day phase to test the equipment, a 105-day phase, and a 520-day phase to simulate a full-length manned mission.

Crews of healthy male cosmonauts volunteered to live and work in an enclosed habitat of sealed interconnecting modules, as if they were on an international space station.

Titze and his colleagues organized the food for the mission and secured commitments from the participants to consume all of the food and to collect all urine each day. They studied twelve men: six for the full 105-day phase of the program, and six for the first 205 days of the 520-day phase.

“It was the participants’ stamina to precisely adhere to the daily menu plans and to accurately collect their urine for months that allowed scientific discovery,” Titze said.

The researchers found that nearly all (95 percent) of the ingested salt was excreted in the urine, but not on a daily basis. Instead, at constant salt intake, sodium excretion fluctuated with a weekly rhythm, resulting in sodium storage. The levels of the hormones aldosterone (a regulator of sodium excretion) and cortisol (no known major role in sodium balance) also fluctuated weekly.

Changes in total body sodium levels fluctuated on monthly and longer cycles, Titze said. Sodium storage on this longer cycle was independent of salt intake and did not include weight gain, supporting the idea that sodium is stored without accompanying increases in water.

The findings suggest that current medical practice and studies that rely on 24-hour urine samples to determine salt intake are not accurate, he said.

“We understand now that there are 7-day and monthly sodium clocks that are ticking, so a one-day snapshot shouldn’t be used to determine salt intake.”

Using newly developed magnetic resonance imaging (MRI) technologies to view sodium, Titze and his colleagues have found that humans store sodium in skin (as they found in their animal studies) and in muscle.

The investigators suspect that genes related to the circadian “clock” genes, which regulate daily rhythms, may be involved in sodium storage and release.

“We find these long rhythms of sodium storage in the body particularly intriguing,” Titze said. “The observations open up entirely new avenues for research.”

The studies were supported by grants from the German Federal Ministry for Economics and Technology/DLR Forschung unter Weltraumbedingungen and the Interdisciplinary Center for Clinical Research at Friedrich-Alexander-University, Erlangen-Nürnberg, Germany. Food products were donated by a number of organizations.

Craig Boerner | Newswise
Further information:
http://www.vanderbilt.edu

More articles from Health and Medicine:

nachricht Organ-on-a-chip mimics heart's biomechanical properties
23.02.2017 | Vanderbilt University

nachricht Researchers identify cause of hereditary skeletal muscle disorder
22.02.2017 | Klinikum der Universität München

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

NASA eyes Pineapple Express soaking California

24.02.2017 | Earth Sciences

New gene for atrazine resistance identified in waterhemp

24.02.2017 | Agricultural and Forestry Science

New Mechanisms of Gene Inactivation may prevent Aging and Cancer

24.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>