News The space medicine thread

[Soheil_Esy]

What happens to your brain on the way to Mars

Cosmic rays could cause brain damage to Mars astronauts

May 01, 2015

No one assumed traveling to Mars would be a particularly safe task, with space debris and supply shortages weighing on the minds of those brave enough to leave Earth. But another danger has now been revealed – cosmic rays which threaten brain damage.

According to neuroscientists, the rays that permeate space can change the structure of neurons in the brain after long periods of exposure. This can result in dimensia-like impairments.

In a study funded by NASA, mice exposed to highly energetic charged particles – such as those found in galactic cosmic rays – showed declines in cognition and damage to neurons and the synapses where nerve impulses are sent and received.

According to Charles Limoli, a University of California-Irvine radiation oncology professor, humans would “without a doubt” face the same issues as the mice, because the particles in cosmic rays can travel through spacecraft and into astronauts' bodies.

“Astronauts may incur cognitive impairments that lead to performance decrements, confusion, increased anxiety and longer-term problems with cognitive health,” said Limoli, whose study appears in the journal Science Advances.

He added that this could leave astronauts less able to respond to situations and solve problems – an issue that could become life-threatening in an emergency situation.

It's a risk that those of us on Earth don't have to worry about – because the planet is protected by its magnetosphere.

The mice were genetically altered to have green fluorescent neurons to aid with analysis. They were exposed to the rays at NASA's Space Radiation Laboratory at the Brookhaven National Laboratory in New York, and analyzed six weeks later.

In addition to changes in the neurons and synapses, the mice showed decreased performance in learning and memory tests. They also lacked curiosity and were slow-moving when participating in experiments involving toys placed in a box with them.

The findings come as NASA continues to develop the capability to send astronauts to an asteroid by 2025 and Mars in the 2030s.

According to NASA spokeswoman Stephanie Schierholz, a Mars mission would take at least 2.5 years: a six-month journey there, at least an 18-month stay on the planet, and a six-month flight back.

Although humans cannot fully escape the harmful rays, Limoli says it may be possible to develop spacecraft with areas of increased shielding.

Other options are also in development, including medicines that could help protect the brain from cosmic rays.

http://rt.com/news/254989-brain-damage-mars-astronauts/

 

[Soheil_Esy]

Spaceflight may increase susceptibility to inflammatory bowel disease

5-Aug-2015

New research in The FASEB Journal suggests that during weightlessness, the microbiome of mouse intestines undergoes changes that render the gut prone to inflammation

Here's the summary of a new research report appearing in the August 2015 issue of The FASEB Journal: Prolonged spaceflight may give you a nasty case of diarrhea. Specifically, when mice were subjected to simulated spaceflight conditions, the balance of bacteria and the function of immune cells in the gut changed, leading to increased bowel inflammation.

"Our study provides useful insights on the cross-regulation of the mucosal immune system, epithelial barrier and commensal bacteria not only in humans in spaceflight or analog, but also in humans on earth that undergo various stresses," said Qing Ge, Ph.D., study author from the Department of Immunology at Peking University Health Science Center in Peking, Beijing.

To make their discovery, Ge and colleagues used four groups of mice. The first and third groups were suspended for 14 days by the tail at a 15 degree head-down tilt with their hindlimbs suspended. Access to food and water was ensured using both water bottles and gel packs and food distributed around the floor of the cage. Animals demonstrated no adverse effects or pronounced weight loss. The second and fourth groups were normal. Starting from day seven, the third and the fourth groups were fed with three percent dextran sulfate sodium dissolved in drinking water to induce inflammatory bowel disease whereas the first and the second groups received plain water. Compared to the second ground control group, the first group with hindlimb suspension revealed altered composition of intestinal bacteria, decreased regulatory T cells, increased neutrophils, and imbalance of pro- and anti-inflammatory cytokines in the colon tissues. The third group with hindlimb suspension had more severe pathology of inflammatory bowel disease when compared to the fourth control group. This includes more weight loss, more severe rectal bleeding and tissue damage and increased death rate in the hindlimb suspended mice after colitis induction.

"We already know that a trip to Mars and back may well have serious, possibly permanent, effects on the bodies of the astronauts," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Now we learn that the hidden passengers on that mission--the bacteria their gut--will be affected as well. This lends further credence to the fact that life on Earth, including the microbiome, evolved under gravity and needs it to thrive."

http://www.eurekalert.org/pub_releases/2015-08/foas-smi080515.php

Simulated microgravity disrupts intestinal homeostasis and increases colitis susceptibility

August 2015

Pingping Li*,1, Junxiu Shi*,1, Peng Zhang†,1, Ke Wang*, Jinglong Li‡, Hongju Liu†, Yu Zhou*, Xi Xu*, Jie Hao*, Xiuyuan Sun*, Xuewen Pang*, Yan Li*, Hounan Wu§, Xiaoping Chen†,2 and Qing Ge*,2

Author Affiliations

*Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, and §Peking University Medical and Health Analytical Center, Peking University Health Sciences Center, Beijing, China; †State Key Laboratory of Space Medicine Fundamentals and Application, Chinese Astronaut Research and Training Center, Beijing, China; and ‡College of Life Sciences and Key Laboratory of Modern Teaching Technology, Shaanxi Normal University, Xian, China

↵2Correspondence: Q.G., Dept. of Immunology, School of Basic Medical Sciences, Peking University Health Sciences Center, 38 Xue Yuan Rd., Beijing, 100191, P. R. China. E-mail: [email protected]; X.C., Chinese Astronaut Research and Training Center, Beijing, 100094, P. R. China. E-mail: [email protected]

↵1 These authors contributed equally to this work.



Abstract

The immune systems can be altered by spaceflight in many aspects, but microgravity-related mucosal immune changes and its clinical significance have not been well studied. The purpose of this study was to investigate whether simulated microgravity influences the intestinal homeostasis and increases the susceptibility to colon inflammation. The hindlimb unloading (HU) mouse model was used to simulate the microgravity condition. Three percent dextran sulfate sodium (DSS) was given to mice to induce colitis. Compared to ground control (Ctrl) mice, the HU ones revealed an impaired intestinal homeostasis and increased susceptibility to DSS-induced colitis. This includes an early-onset, 4-fold expansion of segmented filamentous bacteria (SFB), more than 2-fold decrease in regulatory T (Treg) cell numbers and IL-10 production, ∼2-fold increase in colonic IL-1β expression, 2-fold increase in circulating neutrophils, and colonic neutrophil infiltration. The application of antibiotics ameliorated the Treg and IL-10 reductions but did not significantly dampen neutrophilia and elevated expression of colonic IL-1β. These results indicate that the intestinal microflora and innate immune system both respond to simulated microgravity and together, contribute to the proinflammatory shift in the gut microenvironment. The data also emphasize the necessity for evaluating the susceptibility to inflammatory bowel diseases (IBDs) in distant space travels.—Li, P., Shi, J., Zhang, P., Wang, K., Li, J., Liu, H., Zhou, Y., Xu, X., Hao, J., Sun, X., Pang, X., Li, Y., Wu, H., Chen, X., Ge, Q. Simulated microgravity disrupts intestinal homeostasis and increases colitis susceptibility.

http://www.fasebj.org/content/29/8/3263.abstract

 

[RGClark]

I favor shortened travel times for manned Mars missions to limit the health effects on long periods in space. However, Robert Zubrin has critiqued this particular study here:

Debunking the invalid claims of a space radiation paper.
by Robert Zubrin
Monday, May 11, 2015
http://www.thespacereview.com/article/2749/1

His primary complaint was that the rate of the dosage in this study was millions of times more intense than on an actual Mars mission. That is, the mice were given the large amounts of radiation over seconds where on a Mars mission it would be over years.

Bob Clark

 

[Soheil_Esy]

Long-Duration Spaceflight Increases Depth Ambiguity of Reversible Perspective Figures

October 29, 2015

Astronauts’ brains begin to process visual information differently as they become acclimated to a weightless environment, a new study published in PLoS One reports.

Optical illusions made up of line drawings that can be seen in two different ways, for example a chair that can be seen either facing towards or away from you, are known as “reversible perspective figures.” Studying how people see these figures sheds light on how the human brain takes two-dimensional images from the eyes and puts them together to see in three dimensions.

When people look at these illusions, what they see tends to switch back and forth between the two possible visual interpretations, but one of these views is typically dominant and is seen about 70 percent of the time. This is thought to occur because of the way the brain interprets cues about visual depth. Because the ground is usually closer to us than the sky or ceiling, the brain is more prepared to see lower parts of the drawing as closer, making it easier to see the picture in one way than the other.

A new study, led by Gilles Clément of the Lyon Neuroscience Research Center, studied how astronauts saw these illusions to find out how prolonged weightlessness affects human depth perception. Six astronauts living on the International Space Station were tested on their vision of four reversible perspective figure optical illusions, viewing the figures on a screen and reporting each time their vision switched between the two possible interpretations. The astronauts were tested three times before leaving Earth, four times while in space for a period of up to six months, and another three times after returning.

Reversible perspective figures: a man’s face or old woman begging (left); a Spartan soldier head and helmet or a golfer swinging (right).

Before going into space, the astronauts’ perception of the figures was the same as other people’s, with the dominant interpretation being seen about 70 percent of the time. Once they were in space, the astronauts’ perceptions began to change gradually over time. Instead of seeing one interpretation most of the time, they began to see both possibilities roughly equally. Their vision remained the same immediately after they returned to Earth, but after nine months they had returned to seeing one interpretation of the figure dominantly over the other.

According to the study authors, these results reveal that “depth is not so much the direct result of certain specifiable stimulus cues as it is a mental construction.” The brain pieces together information on visual depth based partly on experience with the environment. In an environment with gravity, this experience tells us that objects in the lower part of the field of vision are probably closer than those in the upper part. For someone who is weightless, the upper field of vision is just as likely to be close as the lower part, giving the brain fewer clues to depth.

In addition to advancing our understanding of how three dimensional vision is processed by the brain, these insights may help future astronauts combat “space fog,” the sense of confusion and disorientation reported after spending time in a weightless environment.

http://www.psypost.org/2015/10/perc...ltered-in-astronauts-during-spaceflight-38867

---------- Post added at 09:51 ---------- Previous post was at 08:01 ----------

Risk of Spaceflight-Induced Intracranial Hypertension/Vision Alterations

07/30/15 04:18:21 PM

2015

Vision changes have been found in approximately 20% of astronauts returning from lengthy International Space Station missions. These changes are thought to be a result of the increase in intracranial pressure brought on by microgravity's characteristic headward fluid shift. Characterized as visual impairment/intracranial pressure, the changes include papilledema (swelling of the optic nerve), globe flattening, choroidal folds, "cotton wool" spots, thickening of the optic nerve, and decreased visual acuity. Since the exact cause of the impairment is undetermined and the long-term consequences remain unknown, Visual Impairment/Intracranial Pressure has been deemed a new human spaceflight risk for astronauts.

Globe Flattening and Optic Nerve Sheath Distension. The above and following images relate to 10 cases identified (of 34 long duration crew) with inflight visual changes and pre-to-postflight refractive changes. Elevated Intracranial Pressure measured postflight in 4 cases.

Optic Disc Edema (swelling).

Choroidal Folds: Parallel grooves in the posterior pole.

Vision Distortion Cotton "wool" spots.

Hyperopic Shifts Up to +1.75 diopters.


http://www.usra.edu/news/features/2012/vision/

Risk Rating

ISS-12 Partially Controlled
Lunar Partially Controlled
Deep Space Journey Uncontrolled
Planetary Uncontrolled

Risk Statement

Given that the microgravity environment causes cephalad fluid shift in astronauts, there is a probability that astronauts will have intracranial hypertension (IHT) to some degree, and if left untreated, could lead to deleterious health effects.

Context

Astronauts on long duration ISS missions have experienced increased intracranial pressure (as measured post flight), ophthalmic anatomical changes and visual performance decrements of varying degrees. Presently, these symptoms have manifested themselves as changes in eye structure such as optic disc edema, globe flattening, choroidal folds, cotton wool spots (CWS), increased retinal nerve fiber layer and/or decreased near vision along with post mission spinal opening pressures ranging between 21 - 28.5 cm H2O for symptomatic astronauts. Present pre, in and post flight data indicate that after approximately 6 months of space flight, 15 of 21 US crewmembers that have been evaluated have shown symptoms of Spaceflight-Induced Intracranial Hypertension (SIIH). The cases are graded based on the criteria in the Spaceflight-Induced Intracranial Hypertension Clinical Practice Guideline. The symptoms considered are refractive change, presences of globe flattening, choroidal folds, cotton wool spots (CWS) and/or increased retinal nerve fiber layer along with the severity of optic disc edema (using the Frisen Scale). Prevalence to date have shown a rate of 71% of those tested with a 24% rate for the most severe classes (3 and 4).

- A preliminary occupational surveillance trial performed on space shuttle astronauts showed changes to the optic nerve diameter, Optical Coherence Tomography (OCT) parameters and visual acuity, even after the short 14 day mission. Although the crewmembers did not complain of fulminant changes in vision, and optic disc edema and choroidal folds were not present, it was apparent on MRIs that changes were occurring but had not reached a particular threshold to cause significant visual disturbance.

- Over 300 postflight questionnaires documented that approximately 29% and 60% of astronauts on short and long-duration missions, respectively, experienced a degradation in distant and near visual acuity.

- Some of these vision changes and elevated ICP have remained unresolved years after flight. The mechanisms that cause Intracranial Hypertension (IHT) in microgravity are not known, and the processes by which eye structure changes occur as a result of IHT are not clearly understood. The impact of multiple missions or of cumulative time in space is not yet established, but suggest a dose response. Greater understanding of the mechanisms for IHT and eye structure changes is necessary to understand and mitigate the hazard and treat the resultant conditions.


https://humanresearchroadmap.nasa.gov/risks/risk.aspx?i=105

 

[Soheil_Esy]

I favor shortened travel times for manned Mars missions to limit the health effects on long periods in space.

Bob Clark

Why the best Mars colonists could come from places like Iran and China


December 15, 2015


NASA is now hiring astronauts for trips to space and Mars that would blast them with radiation, but Crave's Eric Mack learns that some corners of the world already get a similar treatment.

On Monday, NASA officially opened an application window for the next generation of American astronauts it hopes to send to the International Space Station, lunar orbit and eventually to Mars. But to find the best candidates for dealing with the harsh levels of radiation in space and on the Red Planet, the agency may want to consider looking beyond the borders of the United States for applicants.

One of the biggest challenges in sending astronauts into deep space or setting up a base on Mars is dealing with the radiation from the cosmic rays that our sun and other stars send flying around the universe. Earth's atmosphere and magnetic field deflect the worst of this radiation, but Mars has no substantial magnetic field, which has in turn allowed much of its atmosphere to be lost to space over the millennia.

Spacecraft can be equipped with radioactive shielding to some extent, and a base on Mars could also be constructed essentially underground, using several meters of Martian soil to provide radiation protection on par with Earth's atmosphere (this is what Mars One hopes to do). But when it comes to roaming around the surface of Mars in a spacesuit or in a rover, there's no real practical way for those astronauts to avoid some big doses of radiation in the process.


When I attended the New Worlds conference earlier in 2015, there was a discussion of the challenge that cosmic radiation presents for space exploration, and there were some pretty far-fetched possible solutions, like genetically engineering astronauts in the future to handle more radiation.

But I was more intrigued by one partial solution that was mentioned in passing and only half-seriously -- to consider astronaut candidates who are already used to dealing with more exposure to radiation than most of the rest of us.

For years now, scientists have been studying residents of Ramsar, a town in northern Iran that is believed to have the highest levels of naturally occurring background radiation for an inhabited area. Levels up to 80 times the world average (PDF) have been measured in town, yet studies of the few thousand people living in the area show rates of lung cancer are actually below average. In fact, research shows that a gene responsible for the production of white blood cells and so-called "natural killer cells" that attack tumors was more strongly expressed among the population.


In other words, there may be no need to engage in controversial "editing" of human genetics to create radiation-resistant astronauts because there might already be good prospects in a few corners of the world.

Besides Ramsar, the beaches near Guarapari, Brazil, also exhibit very high levels of natural radiation. People in Yangjiang, China, live with radiation levels three times the world average but have below-average cancer levels, and the story is the same in Karunagappally, India.

Unfortunately, none of the people from these areas would be eligible for the program NASA is now hiring for -- the agency is only looking for American applicants. So who in the United States might be best suited for withstanding the most cosmic radiation?


As it turns out, I think it might be me. According to the US Nuclear Regulatory Commission and the National Radiation Map, Colorado -- where my family has hailed from for generations -- has some of the highest levels of background radiation in the country thanks to the high altitude and naturally occurring radioactive elements working their way up from the Earth.


Today, I'm actually about 50 miles south of the Colorado border, but I'm living at a higher elevation than Denver, and previous reporting has taught me that radon levels are actually quite high in the neighborhood as well.

Unfortunately, I am quite content just writing about space exploration and have no interest in ever leaving this planet myself. (As witness our CraveCast episode, Who wants to die on Mars?) Besides, some of my neighbors -- who have lived with this region's natural radiation for many more generations than my family has -- would probably make better candidates.

So if NASA is unwilling to change its eligibility requirements to consider candidates from northern Iran, perhaps the organization ought to consider sending a recruiter to Taos Pueblo in northern New Mexico instead.

February 28, 2002

http://ecolo.org/documents/documents_in_english/ramsar-natural-radioactivity/hbra.jpg
High Background Radiation Areas Around the World.
Numbers given are in mSv/year.
Figure adapted from Health Research Foundation, Kyoto, Japan, with permission.
http://ecolo.org/documents/documents_in_english/ramsar-natural-radioactivity/ramsar.html

http://www.wmsym.org/archives/2002/proceedings/10/434.pdf

http://www.cnet.com/news/why-the-best-mars-colonists-could-come-from-places-like-iran-and-brazil/

 

[Belcher]

Spaceflight may increase susceptibility to inflammatory bowel disease

5-Aug-2015

New research in The FASEB Journal suggests that during weightlessness, the microbiome of mouse intestines undergoes changes that render the gut prone to inflammation

Here's the summary of a new research report appearing in the August 2015 issue of The FASEB Journal: Prolonged spaceflight may give you a nasty case of diarrhea. Specifically, when mice were subjected to simulated spaceflight conditions, the balance of bacteria and the function of immune cells in the gut changed, leading to increased bowel inflammation.

"Our study provides useful insights on the cross-regulation of the mucosal immune system, epithelial barrier and commensal bacteria not only in humans in spaceflight or analog, but also in humans on earth that undergo various stresses," said Qing Ge, Ph.D., study author from the Department of Immunology at Peking University Health Science Center in Peking, Beijing.

To make their discovery, Ge and colleagues used four groups of mice. The first and third groups were suspended for 14 days by the tail at a 15 degree head-down tilt with their hindlimbs suspended. Access to food and water was ensured using both water bottles and gel packs and food distributed around the floor of the cage. Animals demonstrated no adverse effects or pronounced weight loss. The second and fourth groups were normal. Starting from day seven, the third and the fourth groups were fed with three percent dextran sulfate sodium dissolved in drinking water to induce inflammatory bowel disease whereas the first and the second groups received plain water. Compared to the second ground control group, the first group with hindlimb suspension revealed altered composition of intestinal bacteria, decreased regulatory T cells, increased neutrophils, and imbalance of pro- and anti-inflammatory cytokines in the colon tissues. The third group with hindlimb suspension had more severe pathology of inflammatory bowel disease when compared to the fourth control group. This includes more weight loss, more severe rectal bleeding and tissue damage and increased death rate in the hindlimb suspended mice after colitis induction.

"We already know that a trip to Mars and back may well have serious, possibly permanent, effects on the bodies of the astronauts," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Now we learn that the hidden passengers on that mission--the bacteria their gut--will be affected as well. This lends further credence to the fact that life on Earth, including the microbiome, evolved under gravity and needs it to thrive."

http://www.wordsiseek.com/

Had a great time reading the whole thread.

 

[Soheil_Esy]

Fungi on Mars?

Published: 9:26pm, 7 May, 2021

David Flannery, lecturer of Earth and planetary sciences at the Queensland University of Technology and a member of the Nasa Mars 2020 mission science team, said
...
because the surface is not habitable for life,” Flannery said.
...
“The reason for that is the soil is toxic. The surface is bathed in deadly radiation all the time.

https://www.scmp.com/news/china/science/article/3132711/fungi-mars-researchers-claim-signs-life-red-planet
​

In this regard, Serge Brunier's Bahman 22 commentary on the
French television :

"It is simply impossible for humans to survive a trip to Mars and settle there due to the most deadly radiations.
In a nutshell, Mars is Fukushima plus Chernobyl."

https://archive.ph/rX5Qq/0e6e51a40e5767d7750f684632361ee035afab6f/scr.png ; http://web.archive.org/web/20210421105624/https://twitter.com/10943_Brunier/status/962341396995854336 ; https://archive.ph/rX5Qq
▲ 1. Si vous avez aimé, ou détesté, notre prestation sur LCI à propos de la Falcon Heavy et Elon Musk, on remet ça demain avec Xavier Pasco sur BFMTV entre 14 h 10 et 14 h 30. 10 Feb 2018

He campaigns for an exploration of the Solar System through unmanned spacecraft, but fights against crewed spaceflight.[1]

Serge Brunier - Wikipedia

en.wikipedia.org

 

[N_Molson]

Serge Brunier

News reporter and writer with a strong interest in astronomy.

Not a scientific.