The Cellular Secrets of “Young Blood” Are Starting to Be Unlocked
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.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Here are the promising studies covered in this week's Friday Five, featuring interviews with Dr. David Spiegel, associate chair of psychiatry and behavioral sciences at Stanford, and Dr. Filip Swirski, professor of medicine and cardiology at the Icahn School of Medicine at Mount Sinai.
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Here are the promising studies covered in this week's Friday Five, featuring interviews with Dr. David Spiegel, associate chair of psychiatry and behavioral sciences at Stanford, and Dr. Filip Swirski, professor of medicine and cardiology at the Icahn School of Medicine at Mount Sinai.
- Breathing this way cuts down on anxiety*
- Could your fasting regimen make you sick?
- This type of job makes men more virile
- 3D printed hearts could save your life
- Yet another potential benefit of metformin
* This video with Dr. Andrew Huberman of Stanford shows exactly how to do the breathing practice.
This podcast originally aired on March 3, 2023.
Breakthrough drones deliver breast milk in rural Uruguay
Until three months ago, nurse Leopoldina Castelli used to send bottles of breast milk to nourish babies in the remote areas of Tacuarembó, in northern Uruguay, by way of ambulances or military trucks. That is, if the vehicles were available and the roads were passable, which wasn’t always the case. Now, five days per week, she stands by a runway at the hospital, located in Tacuarembó’s capital, watching a drone take off and disappear from view, carrying the milk to clinics that serve the babies’ families.
The drones can fly as far as 62 miles. Long distances and rough roads are no obstacles. The babies, whose mothers struggle to produce sufficient milk and cannot afford formula, now receive ample supplies for healthy growth. “Today we provided nourishment to a significantly larger number of children, and this is something that deeply moves me,” Castelli says.
About two decades ago, the Tacuarembó hospital established its own milk bank, supported by donations from mothers across Tacuarembó. Over the years, the bank has provided milk to infants immediately after birth. It's helped drive a “significant and sustained” decrease in infant mortality, says the hospital director, Ciro Ferreira.
But these children need breast milk throughout their first six months, if not longer, to prevent malnutrition and other illnesses that are prevalent in rural Tacuarembó. Ground transport isn't quick or reliable enough to meet this goal. It can take several hours, during which the milk may spoil due to a lack of refrigeration.
The battery-powered drones have been the difference-maker. The project to develop them, financed by the UNICEF Innovation Fund, is the first of its kind in Latin America. To Castelli, it's nothing short of a revolution. Tacuarembó Hospital, along with three rural clinics in the most impoverished part of Uruguay, are its leaders.
"This marks the first occasion when the public health system has been directly impacted [by our technology]," says Sebastián Macías, the CEO and co-founder of Cielum, an engineer at the University Republic, which collaborated on the technology with a Uruguayan company called Cielum and a Swiss company, Rigitech.
The drone can achieve a top speed of up to 68 miles per hour, is capable of flying in light rain, and can withstand winds of up to 30 miles per hour at a maximum altitude of 120 meters.
"We have succeeded in embracing the mothers from rural areas who were previously slipping through the cracks of the system," says Ferreira, the hospital director. He envisions an expansion of the service so it can improve health for children in other rural areas.
Nurses load the drone for breast milk delivery.
Sebastián Macías - Cielum
The star aircraft
The drone, which costs approximately $70,000, was specifically designed for the transportation of biological materials. Constructed from carbon fiber, it's three meters wide, two meters long and weighs 42 pounds when fully loaded. Additionally, it is equipped with a ballistic parachute to ensure a safe descent in case the technology fails in midair. Furthermore, it can achieve a top speed of 68 miles per hour, fly in light rain, and withstand winds of 30 miles per hour at a height of 120 meters.
Inside, the drones feature three refrigerated compartments that maintain a stable temperature and adhere to the United Nations’ standards for transporting perishable products. These compartments accommodate four gallons or 6.5 pounds of cargo. According to Macías, that's more than sufficient to carry a week’s worth of milk for one infant on just two flights, or 3.3 pounds of blood samples collected in a rural clinic.
“From an energy perspective, it serves as an efficient mode of transportation and helps reduce the carbon emissions associated with using an ambulance,” said Macías. Plus, the ambulance can remain available in the town.
Macías, who has led software development for the drone, and three other technicians have been trained to operate it. They ensure that the drone stays on course, monitor weather conditions and implement emergency changes when needed. The software displays the in-flight positions of the drones in relation to other aircraft. All agricultural planes in the region receive notification about the drone's flight path, departure and arrival times, and current location.
The future: doubling the drone's reach
Forty-five days after its inaugural flight, the drone is now making five flights per week. It serves two routes: 34 miles to Curtina and 31 miles to Tambores. The drone reaches Curtina in 50 minutes while ambulances take double that time, partly due to the subpar road conditions. Pueblo Ansina, located 40 miles from the state capital, will soon be introduced as the third destination.
Overall, the drone’s schedule is expected to become much busier, with plans to accomplish 20 weekly flights by the end of October and over 30 in 2024. Given the drone’s speed, Macías is contemplating using it to transport cancer medications as well.
“When it comes to using drones to save lives, for us, the sky is not the limit," says Ciro Ferreira, Tacuarembó hospital director.
In future trips to clinics in San Gregorio de Polanco and Caraguatá, the drone will be pushed to the limit. At these locations, a battery change will be necessary, but it's worth it. The route will cover up to 10 rural Tacuarembó clinics plus one hospital outside Tacuarembó, in Rivera, close to the border with Brazil. Currently, because of a shortage of ambulances, the delivery of pasteurized breast milk to Rivera only occurs every 15 days.
“The expansion to Rivera will include 100,000 more inhabitants, doubling the healthcare reach,” said Ferreira, the director of the Tacuarembó Hospital. In itself, Ferreira's hospital serves the medical needs of 500,000 people as one of the largest in Uruguay's interior.
Alejandro Del Estal, an aeronautical engineer at Rigitech, traveled from Europe to Tacuarembó to oversee the construction of the vertiports – the defined areas that can support drones’ take-off and landing – and the first flights. He pointed out that once the flight network between hospitals and rural polyclinics is complete in Uruguay, it will rank among the five most extensive drone routes in the world for any activity, including healthcare and commercial uses.
Cielum is already working on the long-term sustainability of the project. The aim is to have more drones operating in other rural regions in the western and northern parts of the country. The company has received inquiries from Argentina and Colombia, but, as Macías pointed out, they are exercising caution when making commitments. Expansion will depend on the development of each country’s regulations for airspace use.
For Ferreira, the advantages in Uruguay are evident: "This approach enables us to bridge the geographical gap, enhance healthcare accessibility, and reduce the time required for diagnosing and treating rural inhabitants, all without the necessity of them traveling to the hospital,” he says. "When it comes to using drones to save lives, for us, the sky is not the limit."