Shoot for the Moon: Its Surface Contains a Pot of Gold
An astronaut standing on the Moon.
Here's a riddle: What do the Moon, nuclear weapons, clean energy of the future, terrorism, and lung disease all have in common?
One goal of India's upcoming space probe is to locate deposits of helium-3 that are worth trillions of dollars.
The answer is helium-3, a gas that's extremely rare on Earth but 100 million times more abundant on the Moon. This past October, the Lockheed Martin corporation announced a concept for a lunar landing craft that may return humans to the Moon in the coming decade, and yesterday China successfully landed the Change-4 probe on the far side of the Moon. Landing inside the Moon's deepest crater, the Chinese achieved a first in space exploration history.
Meanwhile, later this month, India's Chandrayaan-2 space probe will also land on the lunar surface. One of its goals is to locate deposits of helium-3 that are worth trillions of dollars, because it could be a fuel for nuclear fusion energy to generate electricity or propel a rocket.
The standard way that nuclear engineers are trying to achieve sustainable fusion uses fuels that are more plentiful on Earth: deuterium and tritium. But MIT researchers have found that adding small amounts of helium-3 to the mix could make it much more efficient, and thus a viable energy source much sooner that once thought.
Even if fusion is proven practical tomorrow, any kind of nuclear energy involves long waits for power plant construction measured in decades. However, mining helium-3 could be useful now, because of its non-energy applications. A major one is its ability to detect neutrons coming from plutonium that could be used in terrorist attacks. Here's how it works: a small amount of helium-3 is contained within a forensic instrument. When a neutron hits an atom of helium-3, the reaction produces tritium, a proton, and an electrical charge, alerting investigators to the possibility that plutonium is nearby.
Ironically, as global concern about a potential for hidden nuclear material increased in the early 2000s, so did the supply of helium-3 on Earth. That's because helium-3 comes from the decay of tritium, used in thermonuclear warheads (H-bombs). Thousands of such weapons have been dismantled from U.S. and Russian arsenals, making helium-3 available for plutonium detection, research, and other applications--including in the world of healthcare.
Helium-3 can help doctors diagnose lung diseases, since it enables imaging of the lungs in real time.
Helium-3 dramatically improves the ability of doctors to image the lungs in a range of diseases including asthma, chronic obstructive pulmonary disease and emphysema, cystic fibrosis, and bronchopulmonary dysplasia, which happens particularly in premature infants. Specifically, helium-3 is useful in magnetic resonance imaging (MRI), a procedure that creates images from within the body for diagnostic purposes.
But while a standard MRI allows doctors to visualize parts of the body like the heart or brain, it's useless for seeing the lungs. Because lungs are filled with air, which is much less dense than water or fat, effectively no signals are produced that would enable imaging.
To compensate for this problem, a patient can inhale gas that is hyperpolarized –meaning enhanced with special procedures so that the magnetic resonance signals from the lungs are finally readable. This gas is safe to breathe when mixed with enough oxygen to support life. Helium-3 is one such gas that can be hyperpolarized; since it produces such a strong signal, the MRI can literally see the air inside the lungs and in all of the airways, revealing intricate details of the bronchopulmonary tree. And it can do this in real time
The capability to show anatomic details of the lungs and airways, and the ability to display functional imaging as a patient breathes, makes helium-3 MRI far better than the standard method of testing lung function. Called spirometry, this method tells physicians how the lungs function overall, but does not home in on particular areas that may be causing a problem. Plus, spirometry requires patients to follow instructions and hold their breath, so it is not great for testing young children with pulmonary disease.
In recent years, the cost of helium-3 on Earth has skyrocketed.
Over the past several years, researchers have been developing MRI for lung testing using other hyperpolarized gases. The main alternative to helium-3 is xenon-129. Over the years, researchers have learned to overcome certain disadvantages of the latter, such as its potential to put patients to sleep. Since helium-3 provides the strongest signal, though, it is still the best gas for MRI studies in many lung conditions.
But the supply of helium-3 on Earth has been decreasing in recent years, due to the declining rate of dismantling of warheads, just as the Department of Homeland Security has required more and more of the gas for neutron detection. As a result, the cost of the gas has skyrocketed. Less is available now for medical uses – unless, of course, we begin mining it on the moon.
The question is: Are the benefits worth the 239,000-mile trip?
The Cellular Secrets of “Young Blood” Are Starting to Be Unlocked
Fabrisia Ambrosio (center) surrounded by her lab staff.
The quest for an elixir to restore youthful health and vigor is common to most cultures and has prompted much scientific research. About a decade ago, Stanford scientists stitched together the blood circulatory systems of old and young mice in a practice called parabiosis. It seemed to rejuvenate the aged animals and spawned vampirish urban legends of Hollywood luminaries and tech billionaires paying big bucks for healthy young blood to put into their own aging arteries in the hope of reversing or at least forestalling the aging process.
It was “kind of creepy” and also inspiring to Fabrisia Ambrosio, then thousands of miles away and near the start of her own research career into the processes of aging. Her lab is at the University of Pittsburgh but on this cold January morning I am speaking with her via Zoom as she visits with family near her native Sao Paulo, Brazil. A gleaming white high rise condo and a lush tropical jungle split the view behind her, and the summer beach is just a few blocks away.
Ambrosio possesses the joy of a kid on Christmas morning who can't wait to see what’s inside the wrapping. “I’ve always had a love for research, my father was a physicist," she says, but interest in the human body pulled her toward biology as her education progressed in the U.S. and Canada.
Back in Pittsburgh, her lab first extended the work of others in aging by using the simpler process of injecting young blood into the tail vein of old mice and found that the skeletal muscles of the animals “displayed an enhanced capacity to regenerate.” But what was causing this improvement?
When Ambrosio injected old mice with young blood depleted of EVs, the regenerative effect practically disappeared.
The next step was to remove the extracellular vesicles (EVs) from blood. EVs are small particles of cells composed of a membrane and often a cargo inside that lipid envelope. Initially many scientists thought that EVs were simply taking out the garbage that cells no longer needed, but they would learn that one cell's trash could be another cell's treasure.
Metabolites, mRNA, and myriad other signaling molecules inside the EV can function as a complex network by which cells communicate with others both near and far. These cargoes can up and down-regulate gene expression, affecting cell activity and potentially the entire body. EVs are present in humans, the bacteria that live in and on us, even in plants; they likely communicate across all forms of life.
Being inside the EV membrane protects cargo from enzymes and other factors in the blood that can degrade it, says Kenneth Witwer, a researcher at Johns Hopkins University and program chair of the International Society for Extracellular Vesicles. The receptors on the surface of the EV provide clues to the type of cell from which it originated and the cell receptors to which it might later bind and affect.
When Ambrosio injected old mice with young blood depleted of EVs, the regenerative effect practically disappeared; purified EVs alone were enough to do the job. The team also looked at muscle cell gene expression after injections of saline, young blood, and EV-depleted young blood and found significant differences. She believes this means that the major effect of enhanced regenerative capacity was coming from the EVs, though free floating proteins within the blood may also contribute something to the effect.
One such protein, called klotho, is of great interest to researchers studying aging. The name was borrowed from the Fates of Greek mythology, which consists of three sisters; Klotho spins the thread of life that her sisters measure and cut. Ambrosio had earlier shown that supplementing klotho could enhance regenerative capacity in old animals. But as with most proteins, klotho is fragile, rapidly degrading in body fluids, or when frozen and thawed. She suspected that klotho could survive better as cargo enclosed within the membrane of an EV and shielded from degradation.
So she went looking for klotho inside the EVs they had isolated. Advanced imaging technology revealed that young EVs contained abundant levels of klotho mRNAs, but the number of those proteins was much lower in EVs from old mice. Ambrosio wrote in her most recent paper, published in December in Nature Aging. She also found that the stressors associated with aging reduced the communications capacity of EVs in muscle tissue and that could be only partially restored with young blood.
Researchers still don't understand how klotho functions at the cellular level, but they may not need to know that. Perhaps learning how to increase its production, or using synthetic biology to generate more copies of klotho mRNA, or adding cell receptors to better direct EVs to specific aging tissue will be sufficient to reap the anti-aging benefits.
“Very, very preliminary data from our lab has demonstrated that exercise may be altering klotho transcripts within aged extracellular vesicles" for the better Ambrosio teases. But we already know that exercise is good for us; understanding the cellular mechanism behind that isn't likely to provide additional motivation to get up off the couch. Many of us want a prescription, a pill that is easy to take, to slow our aging.
Ambrosio hopes that others will build upon the basic research from her lab, and that pharmaceutical companies will be able to translate and develop it into products that can pass through FDA review and help ameliorate the diseases of aging.
Podcast: Should Scientific Controversies Be Silenced?
The recent Joe Rogan/Spotify controversy prompts the consideration of tough questions about expertise, trust, gatekeepers, and dissent.
The "Making Sense of Science" podcast features interviews with leading medical and scientific experts about the latest developments and the big ethical and societal questions they raise. This monthly podcast is hosted by journalist Kira Peikoff, founding editor of the award-winning science outlet Leaps.org.
The recent Joe Rogan/Spotify backlash over the misinformation presented in his recent episode on the Covid-19 vaccines raises some difficult and important bioethical questions for society: How can people know which experts to trust? What should big tech gatekeepers do about false claims promoted on their platforms? How should the scientific establishment respond to heterodox viewpoints from experts who disagree with the consensus? When is silencing of dissent merited, and when is it problematic? Journalist Kira Peikoff asks infectious disease physician and pandemic scholar Dr. Amesh Adalja to weigh in.
Dr. Amesh Adalja, Senior Scholar, Johns Hopkins Center for Health Security and an infectious disease physician
Listen to the Episode
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.