NASA Kelly twins study shows harsh effects of space flight and a brutal return to Earth

https://www.washingtonpost.com/scie...rsh-effects-space-flight-brutal-return-earth/

 

Two of the ten scientists on this project are from Stanford.
http://med.stanford.edu/gbsc/nasa-twins.html

One of them Mike Snyder is involved in the multi-omics work on ME/CFS at Stanford (Fereshteh Jahaniani leading the project is on his staff) as well as a recent scientific board member of OMF. He is also the chair of Genetics at Stanford, so a very important ally.

For those interested Mike Snyder did a series of 8 videos to explain multi-omics for NASA

NASA’s Twins Study Explores Space Through You: Videos Highlight Omics
https://www.nasa.gov/cont…/exploring-space-through-you-omics

Omics Video Miniseries:

1 Introduction to Omics: 360 Degree View of You
2 Genomics: Genome, The Long and Winding Road
3 Transcriptomics: Releasing the Messengers
4 Proteomics: Proteins at Work
5 Epigenomics: Your Epigenome and Environment
6 Metabolomics: You Are What You Eat
7 Microbiomics: The Living World In and On You
8 Omics: Advancing Personalized Medicine from Space to Earth

 

There are several factors in this research effort which either match or differentiate problems of astronauts and ME/CFS patients. One strong similarity is orthostatic intolerance due to inactivity. Astronauts show this so strongly on return that some have needed to be carried when first back in a one-gee environment. Another is reactivation of herpes viruses, though this stays below the threshold usually set for diagnosing active herpes infections, unless you go looking for evidence. A third similarity is the parallels between physical deterioration and cognitive impairment.

Differences: 1) all astronauts pass rigorous physical and psychological screening, and don't fly unless they are in excellent condition; 2) even low-Earth orbits below the Van Allen belts are subject to increased radiation exposure, which you do see in pilots and crew of jet aircraft, but not in patients; 3) nobody doubts that astronauts are motivated to return to good physical performance.

Even with all the normal explanations removed, it still takes something like a year to recover from prolonged spaceflight in microgravity ("zero gee"). A few weeks of graded exercise therapy would not do. There are also signs that immune system activation takes place both on entry into the space environment and on return to Earth surface environment. You might explain the first by low-level radiation exposure, which is known to increase immune activation in the short term, but this fails badly to explain activation on return.

What definitely does change is circulatory function, particularly venous return to the heart, which is mostly driven by contractions of leg muscles and tiny valves in veins. No matter how large arterial pressure changes may be, very little of this will make it through capillaries to move venous blood. In this sense people in microgravity environments resemble those in the study by David Systrom's group who had measurable low ventricular filling pressures. Problems on return to Earth would be a natural result of atrophy of this function.

Now I'm going to go out on a limb and speculate on something that seems obvious from a physics perspective. Immune cells aren't very good at swimming. They depend on blood circulation to move them to distant parts of the body and back to communicate with other immune cells. The time to respond to an immune challenge and the efficiency with which a system produces the specific response needed, where it is needed, is obviously dependent on the rate of transport. If I were thinking in terms of a system of differential equations describing immune performance, when we know that specialized cells do quite a bit of communication with other specialized cells, not necessarily of the same type, I would expect circulatory function to be a major factor in immune health. In cases of heart failure this is matched by clinical observations.

ME/CFS patients regularly have cardiac output in the same range as patients with heart failure, but mainly when upright, which is seldom measured. This is not counted as heart failure because these patients can recover by lying down, which is not true of patients with true heart failure.

I'm postulating that this episodic impairment of circulatory function also affects immune function, which can lead to reactivated viral infections and misdirected immune responses.

 

This is not quite accurate. Astronauts do exercise while at ISS. If I remember well, 1-2 hour/ day

 

@Milo

Interesting point, but you should check on what they mean by exercise, and how it affects the physiological changes they experience in microgravity.

Unless you are really severely affected I'm guessing you use your legs for more than 2 hours a day. At Earth gravity it is really hard to avoid constantly exercising muscles associated with upright posture and control of blood pressure and circulation while upright. To get the same effect in microgravity, simply for testing purposes, the astronaut in this study had to use the equivalent of a negative g-suit, a low pressure device that operated on his lower body. Most astronauts don't do this. The exercise they get is different from the kind of exercise anyone living on Earth experiences daily, even if we don't consider it a separate activity with a name, and some parts of their bodies are way underused. Note the way fluids are redistributed in people in microgravity.

Aside: I wonder if some of us experience such changes, leading to mysterious sinus problems and headaches. Unfortunately, doctors are not in the habit of measuring fluid distribution in patients.

On Earth we have a constant battle against gravity which most people are able to overlook. Not us. Most species are better adapted than humans are because they've been in their current normal posture longer. As speculation, I'd guess that human inventions like chairs and beds would appear unusual to other intelligent species. We won't know until we meet some. I keep hoping to run into one intelligent species some day, since I'm not sure I've ever seen one.

 

What I want to emphasize in connection with this topic is that the people affected are not subject to any of the putative causes of ME/CFS, yet they can take a year or more to recover.

There are measurable changes in expression of genes and activation of viral infections, as well as basic physiological functions concerning cardiac output, baryreflex sensitivity and fluid distribution. NASA is running new studies of the effects of being bedbound on healthy volunteers, because of gaps in studies done back before human astronauts were first sent into space.

If we haven't understood what happens to healthy people in this situation, how on Earth do we expect to understand what happens to people recovering from infections or immune challenges?

Added: in all the above I somehow missed mentioning metabolomics entirely. This is not because metabolic diseases are unknown or extremely rare. All of us know people who are diabetic. Most studies of metabolism have been done on athletes, and often elite athletes. Except for diseases where the dysfunction results in signs like sugar in urine most people with defects in metabolism have been ignored until they end up in hospitals. From the standpoint of medical science we simply don't understand what is going on in most people who are exercise intolerant.

When I first learned about CPET results that showed a decline on consecutive days of testing I was astonished that this had not appeared in the literature earlier. The equipment required is not unusual. When I discussed this with people who worked in hospitals that had such gear, I was told "Oh yes, we see that fairly regularly, but doctors tell us it doesn't mean anything except that patients are very deconditioned." How to correct this is left as an exercise for the patient. (Pun intended.)