Scientists have been running controlled anti-aging and rejuvenationtests for a century—but on rodents, not people. (Photo:Shutterstock)

In 2016, a tiny startup announced an experiment that seemedequal parts medieval sorcery and science fiction: It would injectolder people with the blood plasma of young donors in a bid toslow aging.

For three years, Ambrosia Chief Executive Officer Jesse Karmazincharged patients $8,000 to infuse one liter of plasma as part of anunorthodox, crowd-funded clinical trial. Karmazin promisedextraordinary results—going so far as to proclaim in mediainterviews that his treatment “comes pretty close” to immortality.

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Last week, the U.S. Food and Drug Administration poured coldwater on his improbable dream. The regulator, echoing individualmedical experts, issued a warning saying the treatment's benefitsare unproven and that the practice could be harmful.

“We're concerned that some patients are being preyed upon byunscrupulous actors touting treatments of plasma from young donorsas cures and remedies,” the FDA said, without naming any companiesor individuals. Ambrosia—named after the mythical food thatconferred immortality on Greek gods—announced soon after that itwas ceasing all treatments.

Karmazin hasn't responded to repeated requests for comment sincethe FDA announcement. Last month, as he planned to open infusionclinics in New York and elsewhere, he explained to Bloomberg theprovenance of his startup and his hopes for success. But now thatthe federal government has gotten involved, his dream may insteadseem like a cautionary tale—one in which America's perpetualobsessions of youth and technology joined together for onefantastical, and ultimately doomed, moment.

New territory?

Testing whether young plasma can breathe new life into olderpatients is fairly unremarkable in the medical world. Scientistshave been running controlled anti-aging and rejuvenation tests fora century—but on rodents, not people.

For 150 years, scientists have been stitching together old miceand young mice to allow their blood to pump through each other'sveins. The practice, called parabiosis, often resulted in lab ratscontracting infections and dying, and in the 1970s it was largelydiscarded. But advances over the past 15 years have revived thetechnique. Nowadays, parabiosis pairs are sniffing around cages inuniversity laboratories across America.

Some studies purport to show the blood of young mice havingrejuvenated the aging organs of older mice, making them stronger,smarter and healthier. It has even made their fur shinier, otherresearchers have claimed.

Dr. Gurpreet Baht of Duke University's Molecular PhysiologyInstitute said he is working with four parabiosis pairs hepersonally sewed together. He said his research found that freshblood circulation made the older mice's blood cells “really actyoung again,” even healing bone fractures faster than normal. Buthe was dismissive when it came to claims related to humans.

“We're still at the level of mouse models,” Baht said. “I don'tthink the information is out there for humans. Humans are morecomplicated.”

In 2014, Dr. Saul Villeda of the University of California, SanFrancisco, led a study in which the blood plasma of three-month oldmice was injected into 18-month-old mice (a mouse's lifespan isabout 2 years). Villeda said the older mice performed significantlybetter after the infusion. But experts regularly emphasize that, inmedical testing, mice and humans are decidedly not the same.

Karmazin had just graduated from Stanford University MedicalSchool around the time Villeda's study was published. Originallyfrom Palm Beach Gardens, Florida, Karmazin said he had long beeninterested in the “often overlooked” field of aging.

While observing a blood transfusion in an emergency room,Karmazin said he had his “eureka moment.”

“I was thinking about the [mice] research and it just occurredto me, like 'wow, transfusions are the same thing for humans,'” hesaid. Karmazin said he dropped out half-way through his residencyand founded Ambrosia. On the company's website, he wrote:“Experiments in mice called parabiosis provided the inspiration todeliver treatments with young plasma.”

Karmazin, 34, wasn't able to practice medicine because he hadn'tcompleted his residency. Instead, he said he partnered withphysicians in California and Florida who agreed to perform plasmainfusions at their own clinics. Karmazin said he provided them withplasma from donors under the age of 25, purchased from bloodbanks.

In his interview with Bloomberg, Karmazin said he had treated150 patients. Their blood was tested in the days before thetreatment and one month after it, allowing a comparison ofbiomarkers. He said he found precancerous cells and amyloids, whichindicate Alzheimer's, had fallen by up to 20 percentpost-treatment. He provided no evidence to support the claim.

Karmazin said plasma recipients with Alzheimer's were “doingtheir finances again” and others with “severe heart disease” wereable to run up stairs. He didn't provide any evidence for thoseclaims, either. Karmazin said he planned to publish the resultsonce they were peer-reviewed, but didn't say where, or who wasdoing the reviewing.

One 62-year-old from southern California said in a telephoneinterview arranged by Karmazin that he had been receiving infusionsfor more than a year. He is only the second person to speakpublicly about his treatment by Ambrosia. The man, a mathematicianwho requested anonymity to protect his medical privacy, said amotorcycle accident in 2011 had left him partially paralyzed. Afterthe infusions, he said he could sleep through the night again andgenerally felt better.

Of mice and men

Leading researchers in the regenerative medicine fieldstrenuously reject Ambrosia's premise.

“Those [mice] studies don't provide a scientific basis for whatAmbrosia is offering,” said Dr. Amy Wagers, co-chairof the Harvard Department of Stem Cell and RegenerativeBiology. Parabiosis conjoins an entire organ system, whereas plasmainfusion is just one element, she said.

“The research we are doing can be sensationalized,” saidVilleda, of the University of California. “In order to avoid hoaxstudies we need appropriate clinical trials.”

Such trials are completed in controlled environments andgoverned in part by federal guidelines. Companies must meet a setof standards before making any health claims. However, Karmazindidn't need the FDA to approve his trial because he was offering apre-approved procedure—a basic blood infusion—as an off-labeltreatment. Still, he sought approval from the Institute ofRegenerative and Cellular Medicine's Institutional Review Board(IRB), an independent group which determines whether a study onhuman subjects is ethical.

Dr. Barbara Krutchkoff, co-chair of the institute's IRB and aconsultant in biomedical studies, said in an interview that shesigned off on Karamzin's study because it was a medically approvedprocedure and “nothing out of the ordinary.”

“People have done weird things over the years to think theycould become younger and this was not the weirdest,” she said,adding that she's faced her own critics for the decision. “They'vesaid 'who do you think you are allowing him to do this?'”

“Some people spend $8,000 to go to the Super Bowl,” Krutchkoffsaid. “If you want to spend $8,000 to get a young person's bloodtransfusion and it feels good, then why the hell not?” Overall, shesaid, the treatment is “no more dangerous than walking across thestreet.”

The possibility of human longevity has been a popular hobby inSilicon Valley. Billionaire tech entrepreneurs such as Peter Thiel,Y Combinator president Sam Altman and Tesla CEO Elon Musk have beenpouring money into bio-engineering startups. The tech industry'sdesire to cheat death was even lampooned in a 2017 episode of HBO's“Silicon Valley.” It showcased human-to-human parabiosis, with ayoung “blood boy” directly transfusing his blood into a wealthy,aging recipient.

Despite the obvious appetite for holy grail startups, whenKarmazin came knocking, venture capital firms didn't answer. “It'sbeen somewhat difficult to raise money,” he said. “I've talked witha number of potential investors, but we haven't raised money atthis point.” He blamed it on people being “squeamish” aboutblood.

As 2019 began, Karmazin said he was excited for the future. Hedescribed plans to open a clinic in New York because it's an“affluent place where people can afford it,” and possibly Texas andOhio soon after.

Then the FDA weighed in.

In their warning, FDA Commissioner Scott Gottlieb and PeterMarks, head of the agency's biologics center, wrote they had becomeaware of people “charging thousands of dollars for infusions thatare unproven and not guided by evidence from adequate andwell-controlled trials.”

“We will consider taking regulatory and enforcement actionsagainst companies that abuse the trust of patients and endangertheir health with uncontrolled manufacturing conditions or bypromoting so-called 'treatments' that haven't been proven safe oreffective for any use,” the regulator said. Hours later, theAmbrosia website was updated to say: “In compliance with the FDAannouncement issued Feb. 19, 2019, we have ceased patienttreatments.”

Premature conclusions

Karmazin hasn't made any public statements since. Krutchkoffsaid Karmazin told her that he was going to “put everything onhold.”

This comes as a relief to Dr. Irina Conboy, a rejuvenationresearcher at the University of California, Berkeley. She saidshe's had concerns about Ambrosia for years. Plasma infusion isonly reserved for life-threatening situations, Conboy said, becauseit can trigger serious side effects, such as allergic reactions,circulatory overload, lung injury and infectious diseasetransmission.

In 2016, she published a paper on mice-to-mice bloodtransfusions. She said Karmazin called her office, leaving avoicemail message to say how much he enjoyed her researchand that it fell into line with the treatment he was providing atAmbrosia. In the message, she said he asked if they couldwork together. Conboy said she never returned his call.

For Conboy, the most frustrating part of the Ambrosia saga isthat it tarnishes the area of regenerative medicine, where she saidscientists are on the brink of ground-breaking discoveries thatcould truly help ailing elderly patients.

“Do not inject yourself with blood,” she said. “Wait a couple ofyears until we have a safe and rational treatment based onscience.”

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