For $8,000, a startup called Ambrosia plans to sell transfusions of young blood for anti-aging purposes.

Another longevity company called Alkahest is also focused on blood. But it's taking a very different approach.

Instead of opening up a clinic to perform transfusions of young blood, Alkahest researchers aim to develop drugs for age-related diseases which are inspired by their work with plasma.

Blood gets a bad rap.

The idea of sharing blood with another person for anything other than a life-saving procedure makes a lot of people squeamish. That's probably why, shortly after word got out that a startup called Ambrosia aimed to sell transfusions of blood from young people to help older people fend off aging, people began to freak out.

Some likened the procedure to the activity of vampires (who, for the record, drink — not transfuse — blood). Others simply said it "raised questions."

Read more: A controversial startup that charges $8,000 to fill your veins with young blood is opening its first clinic

It turns out, though, that there's some solid science behind the idea of studying blood — if not necessarily for linking the bodies of older and younger volunteers, then for identifying key proteins that change with age and could be further tested in drug candidates.

A startup called Alkahest is focused on this kind of work. Alkahest scientists are also studying the potential benefits of an advanced type of blood transfusion in publicly documented clinical trials for age-related diseases including Alzheimer's and Parkinson's, but it is not looking to open up a clinic or connect the bodies of young and older people.

"There have been some really hilarious representations of this, where people get conjoined in order to provide some regenerating activity, but that's not doable," Alkahest CEO and ex-Genentech neuroscientist Karoly Nikolich told Business Insider at a meeting during the J.P. Morgan Healthcare Conference.

In fact, while the science of rejuvenating an older organism by connecting its veins to a younger one is foundational to Alkahest's research, it has little to do with the majority of work it's doing now, Nikolich said.

How linking the veins of an old and a young mouse jump started a quest for longevity

In early experiments in mice and humans, Alkahest founder and Stanford professor Tony Wyss-Coray found that swapping old blood for young blood appeared to provide some limited cognitive benefits to the older organism. China Photos/Getty

Founded in 2014 by Tony Wyss-Coray, the codirector of the Alzheimer’s research center at Stanford University Medical School, Alkahest has received funding from the Michael J. Fox Foundation, which focuses on developing treatments for Parkinson's, as well as from the Hong Kong-based biotech fund Nan Fung Life Sciences and the Spanish pharmaceutical company Grifols. More than a third of Alkahest's management team hail from biotech giant Genentech.

In early experiments in mice, Wyss-Coray used a technique called parabiosis to learn that swapping old blood plasma for young blood plasma appeared to provide some limited cognitive benefits to the older organism. The 150-year-old surgical technique involves exchanging the blood of two living organisms; its name comes from the Greek words para, or "beside," and bio, or "life."

After Wyss-Coray's mouse experiments, he and a team of Alkahest researchers took a big leap and in 2017 completed a month-long study in which they transfused a standard unit of blood plasma from young and healthy human volunteers into nine older adults with mild-to-moderate Alzheimer's disease.

Their results were published this month in the journal JAMA Neurology. Because the study was small and short, the authors were fairly limited in drawing conclusions about what kind of benefits the plasma offered. They wrote that the "treatment was safe, well tolerated, and feasible," and that the findings should be explored further in larger trials.

In the interview with Business Insider, Nikolich described some observed cognitive boons in the older study participants, as tested by a standard screening tool called the Mini-Mental State Examination. Those benefits included an improved sense of self and recognition of one's environment and location, he said.

Read more: Researchers whose work inspired a controversial young blood startup warn that the procedure they're offering is dangerous

Working with blood plasma presents serious challenges. Exchanging the liquid between individuals requires an experienced clinician who must run several complicated and time-consuming tests to ensure there are no serious ill effects. To get the right mixture of plasma for a single recipient, as many as 10 donors may be required.

So although the company is still analyzing the potential benefits of plasma in people with Alzheimer's and Parkinson's, its researchers are also studying drug candidates that don't involve plasma at all.

'The goodies go down and the bad actors go up'

By running thousands of tests on the blood plasma from 18-70 year old donors, Alkahest researchers identified roughly 1,000 proteins that appeared to change with age. Antony Jones/Getty One of the projects that Alkahest researchers are most enthusiastic about involves an oral drug for age-related macular degeneration, a leading cause of vision loss in people over 50.

To identify the central therapeutic ingredient in that drug, Alkahest scientists did years of research on blood plasma in partnership with Spanish pharmaceutical company Grifols. The company also funds a big portion of Alkahest's work in plasma and in 2015 gave Alkahest $50 million, Nikolich said.

Subscribe to Dispensed, our weekly newsletter on pharma, biotech, and healthcare.

After running thousands of tests on plasma that Grifols had collected from 18-70 year old donors, Alkahest researchers identified roughly 1,000 proteins that appeared to change with age. The proteins linked with positive effects seemed to fade away over time, while the proteins tied with negative effects (like vision loss) built up with age.

"Unfortunately the goodies go down and the bad actors go up," said Nikolich.

Testing an eye drug that's based on blood research

Based on that work, Alkahest researchers homed in on a protein that appeared to provide benefits to people with age-related macular degeneration, or AMD. Using that protein, they developed a drug called AKST-4290 which is currently in the second phase of clinical research. Nikolich said that Alkahest plans to launch several larger studies of the drug in people with AMD as well as with Parkinson's later this year.

AMD damages a tiny round area that's part of the eye region responsible for letting us see objects straight ahead. The current standard of care for AMD involves injecting medicine into the eye with a small needle. Although the procedure isn't typically painful, it's inconvenient and can be expensive — especially in places with limited resources such as in many parts of the developing world.

"An oral molecule for AMD would be fantastic," Elizabeth Jeffords, Alkahest's chief commercial and strategy officer and the former vice president of Genentech's ophthalmology franchise, told Business Insider.

Having spent more than a decade at the biotech giant, Jeffords said she found it frustrating that people weren't treating Alkahest as a serious biotech company and were instead focusing on the blood factor.

"We're looking at plasma proteins, and just like any other target in biotech, they're proteins," Jeffords said.