Human Trials of Plasma Exchange

Animal experiments demonstrating the anti-aging effects of exchanging young blood plasma for old have been prominent in the last two months. Several groups are saying it’s time to translate their findings into human trials. But I’ve recently learned that others have been doing this for several years. What can we learn from their results to guide the next steps in experimentation?

I had never heard of Grifols, the Spanish pharmaceutical company that is the world’s largest supplier of albumin. Since 2005, Grifols has been quietly funding world leaders in plasma exchange research in humans. Albutein® is their brand-name solution of human albumin.

Last month, the first results of the Grifol’s AMBAR trial were released. (AMBAR stands for Alzheimer’s Modulation BAlbumin Replacement). It was a much larger-scale phase 2.5 trial, with 496 subjects recruited from sites in Spain and USA, and treated for 14 months. A single treatment consisted of removing 2.5 to 3 litres of blood (more than half the body’s inventory) and replacing it with Albutein. Patients began with 6 weekly treatments, and thereafter there were 12 monthly smaller plasma replacements (0.7 litres), again with Albutein.

Subjects were evaluated with two standard measures, one of cognitive ability and the other of ability to function independently. Most subjects got worse over the year, as AD is a progressive disease. But treated subjects progressed less than half as fast as sham-treated controls. There was enough variation among individuals that even this strong difference in averages was only marginally statistically significant.

Subjects were categorized as “mild” to “moderate” in their cognitive loss. “Moderate” subjects responded a little better than “mild”, within statistical limits.

In the Conboy paper which I recently reviewed, albumin was considered to be just a passive replacement of proteins that every mammal needs. Albumin was replaced in the blood because when harmful signaling proteins were diluted out of the blood, albumin was removed along with it. The body needs the albumin, while the protein signals were doing damage. Henced they replaced the albumin.

But in AMBAR, albumin is considered an active part of the therapy.

[P]lasma albumin from AD patients is more glycated and nitrotyrosinated than plasma from healthy subjects, reducing its ability to inhibit Aβ aggregation Grifols theorized that replacing AD patients’ albumin with therapeutic-grade albumin should overcome this problem. Further, therapeutic-grade albumin should more effectively bind plasma Aβ and sequester it than plasma albumin from AD patients. Albumin may protect neurons by additional mechanisms, including anti-oxidant and anti-inflammatory activities.  [review, referencing  this primary source].

In one branch of the AMBAR program, ¼ of subjects also received intravenous immunoglobulin (IVIG). This consists of antibodies which identify challenges to which the immune system can respond. Grifols has a proprietary IG product called Flebogamma®. The AMBAR trial was unable to detect a benefit from IVIG.

Plasma exchange has a long history for treatment of auto-immune disorders. Some of the diseases of old age are related to autoimmunity (e.g., diabetes, arthritis, chronic inflammation). Older persons have a higher generalized autoimmunity, but a lower incidence of explicitly autoimmune diseases. Presumably, there are antibodies to self that accumulate in the bloodstream with age, and in recent years this has been related to leaky gut disorders. It makes sense to me that blood dilution would be a downstream or stop-gap treatment for autoimmunity, but that better approaches would be directed at the source of the offending antibodies.

Dobri Kiprov was a co-author of the Conboys’ plasma dilution paper. Kiprov’s clinic has been a site in the AMBAR trials, with experience in plasma exchange going back 20 years. Kripov has studied plasma exchange for a variety of diseases. In these treatments, a patient’s blood is removed and separated. The patient’s own red and white blood are returned to him, but his plasma is replace with saline, albumin, and possibly other ingredients. When I spoke to him, he described work which is soon to be published in Alzheimer’s and Dementia involving a proprietary added ingredient in these plasma transfusions. Benefits last at least 6 months, he said, which suggests that there is some epigenetic re-programming of the cellular sources of blood constituents.

Kiprov claims that patients who receive frozen blood plasma for a variety of reasons have fewer adverse reactions when they receive plasma from young donors (18-24) compared to middle-aged donors (35-45). He has seen patients’ immune systems improve, and arthritis symptoms decrease. He’s eager to see formal trials proceed for these conditions (but someone has to fund them).

The bottom line

As a treatment for AD, these results are not impressive. Patients were already quite disabled, and the results were essentially to prolong their end-of-life institutional existence. There are no effective drugs for AD, so compared to any pharmaceutical, AMBAR looks good. But compare these results to Bredesen’s RECODE program, which aims to improve cognition, and in some cases has returned people to productivity from a non-functional state. RECODE works better the earlier you start it, whereas preliminary results suggests that AMBAR is more effective in late stages.

Inflammation is a driver of all the diseases of old age. Pro-inflammatory signals (cytokines) in the blood were among the elements diluted by AMBAR, and it may be that reduction in inflammation fully accounts for the program’s successes.

As a proof of principle, the results are quite informative. A benefit was demonstrated from plasma exchange in humans for the first time. Subjects did not become dramatically younger, despite much more dilution than in the Conboy mouse experiments (reviewed in this space earlier this month). They suggest that simple dilution as pioneered by the Conboys in mice might be effective in slowing senescence but not reducing biological age.

Two plasma exchange doctors were kind enough to help me with this column. I’m grateful to David Haase (TX) and Dobri Kiprov (CA) for offering background and providing direction to my readings.

Suppression of Chloroquine is Scandalous

It’s hardly newsworthy that medical science is distorted by money. But last week, a case arose that is so blatant, so extreme, and so suspiciously criminal that it should become a rallying point for all of us interested in reform. It involves the two best-respected medical journals in the world, and a finding that immediately affected the lives of thousands of patients around the globe. Two papers purported to be derived from a large, worldwide database, but they were quietly withdrawn when the data was requested by outside reviewers, and none could be produced. Where is the outrage? Where is the passion for reform?

Hydroxychloroquine is a cheap, out-of-patent drug that literally millions of travelers have been using for 65 years for prevention of malaria. It is also taken on a daily basis by hundreds of thousands of lupus patients. Its safety profile and side-effects are well established. Front-line doctors in Wuhan told us early that, in combination with zinc, it was the most effective COVID treatment they knew. It had previously been used with success during the SARS epidemic of 2003. European doctors reported anecdotal success with chloroquine/zinc, and it became standard treatment in France, the Netherlands, and elsewhere [review]. There were about 70 ongoing clinical trials before the two articles appeared.

HCQ has been discouraged by Anthony Fauci and segments of the American medical establishment, and I have wondered if they were compromised by their investments. Fauci is associated, ideologically and financially, with vaccines. The primary competitor for HCQ is Remdesivir, belonging to Gilead Sciences, and selling for $1,000 per dose. Billions of dollars have already been invested in developing a COVID vaccine. That COVID seems to be treatable and that the pandemic is fading with the spring weather is welcome news for world health, but it is devastating for investors in Gilead, Moderna, AstraZeneca, and 20 other companies that are racing to produce a COVID vaccine.

Last month, the two most prestigious medical journals in the world reported large studies by prominent researchers, based on a large COVID data set from Asia, Europe, and America. The lead author is from Harvard’s Brigham and Women’s teaching hospital. Here is the Lancet article, claiming that hydroxychloroquine is worse than useless. The data appear to show that people treated with HCQ are dying at 3 times the rate of other, similar patients. Here is the New England Journal article, which analyzes comorbidities but does not mention HCQ.

The Lancet paper had been duly peer-reviewed and rushed into print by editors. But seasoned researchers in the field immediately smelled that something must be wrong. How could this huge database of patients exist, crossing four continents and going back to the earliest days of the virus, when no one thought the records would be valuable? How could comparable conditions be established in hospitals from Capetown to Beijing to New York? And how could a drug in use for 65 years have such powerful lethal side-effects that no one had previously identified?

Questioned and challenged to produce the data behind the study, the authors quickly retracted the paper and refused further comment.

“Dr. Desai declined a request from The Times to be put in contact with a hospital or health care facility that provided its data to Surgisphere. He did not respond to inquiries after the retractions.” NYTimes

Nirav Desai is a physician and researcher from Surgisphere, a small Chicago company that claimed to have compiled the impressive database. Both retracted studies were led by Mandeep R. Mehra, a widely published and highly regarded professor of medicine at Harvard, who may end up being the fall guy for this scandal.

But no one is investigating Surgisphere as the source of a criminal fraud. No one is holding the Lancet journal or its editors or reviewers to account. Certainly no one is questioning the broad system funding and publishing the medical research on which the practice of Western medicine is based. To their credit, Science Magazine published this article, hinting at a scandal and beginning to ask the right questions.

This is happening at a time when the medical establishment is making the largest demands ever on our beliefs and our behaviors. We are locked down based on the computer simulation of a compromised researcher, who also did not document the basis of his computation, and whose predictions have proved spectacularly inflated. Why did we trust him, when he had cried wolf twice previously (EbolaAvian flu)? The liberal-intellectual press and the science journals speak with a unified voice. denouncing anyone who questions vaccines as ‘anti-science’. Every article in Wikipedia and every Google search is plastered with a message that tells us to trust the CDC. The head of Youtube goes on the air to explain why anyone who disagrees with the WHO must have their videos removed.

The largest of the studies evaluating HCQ were discontinued after the Lancet article raised the probability that the studies might be putting lives of experimental subjects at risk. Now they are being re-started, but a fresh scandal has arisen. Dr Meryl Nass has investigated details of the “Soldarity” and “Recovery” trials. She reports that these trials plan to use dosages that are at least 4 times larger than necessary, dosages that have been found to be unsafe in the past, in fact fatal to a few percent of sensitive patients. She does not mention that the trials are leaving out zinc supplementation, which doctors everywhere report to be an essential part of the treatment protocol. The studies have indirect ties to vaccine manufacturers, through the WHO and through the Gates Foundation.

It appears on its face that these trials are designed to fail, and will kill experimental subjects on the way to “proving” that HCQ is an ineffective treatment. These suspicions can only be amplified by an announcement today from FDA that chloroquine cannot be used for COVID cases. This intrusion into physician autonomy is unprecedented. For as long as FDA has existed, its policy has been to permit physicians to freely prescribe drugs off-label for any condition where the individual physician feels it might be useful.

The institutions in which Americans and Europeans have entrusted their health have betrayed our trust. There are narrow implications for the future of HCQ and treatment of COVID, and then there are broader implications about the need for overhauling the profit incentives in medical research.

Narrow perspective

For those of who dare to look beyond our own noses, a concerted campaign to discredit a good, cheap treatment for COVID is a hint that might help us make sense of the bizarre global events of the last five months. This is a real virus, a real pandemic, but it is being exploited for a political agenda far larger than the effects of the disease itself.

  • Why have death rates been consistently overestimated in public reports?
  • Why have hospitals been incentivized to over-report COVID deaths, and to treat patients with ventilators that don’t seem to be helping?
  • Why has CDC failed to recommend simple, inexpensive prevention measures (vitamin D, zinc, immune-enhancing herbs, special measures for nursing homes)?
  • Why have our government agencies encouraged shortcutting of safety tests in “warp-speed” vaccine development, while discrediting simple, cheap treatments (intravenous vitamin C, chloroquine/zinc, Artemisia) that work in other countries?
  • Why has COVID become cause for bailouts of the financial sector that have little to do with the disease, while working families and small businesses have been forced into bankruptcy?

Many geneticists, including two Nobel laureates, cite evidence that COVID seems to be man-made, the product of genetic engineering (excellent technical summary). But this idea is off the table for discussion, censored by both the scientific community and by the mainstream press (original articlesanitized rewrite). Could it be that the same powerful forces benefiting from the lockdown and social control have power to censor both the scientific establishment and the popular press? These may seem wild speculations, but perhaps they are justified by wild events.

The rules we are asked to follow have been maximally destructive to our economy, our institutions, and our culture, while providing far less life-saving benefit than simpler strategies. Maybe the cultural and social isolation were intended to serve a different purpose than the protection of public health.

Broad perspective

“Two major study retractions in one month have left researchers wondering if the peer review process is broken.” NYTimes

The Times calls them “big blunders” but this is far too charitable. A big blunder is when you publish an article without noticing that a plus sign is really a minus. But when you fail to notice that the database of patient cases you are analyzing doesn’t exist, that is a fraud and not a blunder.

We like to think that medical practice is following medical research as the tail follows the dog. But look at the two economies$3.5 trillion per year in health care revenues in America vs an NSF budget of only $8 billion spread over every kind of science. It may be too much to expect the dog to wag the tail when the tail is 500 times larger than the dog.

Meanwhile, medical consumers are voting with their feet. People flock to dietary supplements ($35 billion/year), acupuncturists, chiropractors, and alternative healers. 40% of Americans think that non-standard approaches to cancer are more likely to cure them than chemotherapy and radiation, while most of the purveyors of those alternatives have been driven overseas by aggressive FDA “oversight”.

If the medical science establishment wishes to regain the trust of the American public, they will have to demonstrate that the health of individual patients weighs more heavily in their calculations than the profit motive.

Out With the Old Blood

There is great promise in 2020 that we might be able to make our bodies young without having to explicitly repair molecular damage, but just by changing the signaling environment.

Do we need to add signals that say “young” or remove signals that say “old”?

Does infusion of biochemical signals from young blood plasma rejuvenate tissues of an old animal? Or are there dissolved signal proteins in old animals that must be removed?

For a decade, Irena and Mike Conboy have been telling us removal of bad actors is more important. But just last month, Harold Katcher reported spectacular success by infusing a plasma fraction while taking away nothing. Then, last week, the Conboys came back with a demonstration of the rejuvenating power of simple dilution. [Link to their new paper]

Dilution procedure

They simply replaced half of the blood plasma in 2-year-old mice with a saline solution containing 5% albumin. What is albumin? Blood plasma is chock full of dissolved proteins, about 10% by weight. About half of these are termed albumin. Albumin is the generic portion. It doesn’t change through the lifetime. It doesn’t carry information by itself. But albumin transports nutrients and minerals through the body.

The Conboys took care to show that albumin has no rejuvenation power on its own, and had nothing to do with their experimental results. Rather, they had to replenish albumin in diluting blood, because the animals would be sickened if half their albumin were removed. Replacing the albumin in a transfusion is akin to replacing the volume of water or maintaining the salinity.

In preparation for this experiment, the Conboys have invested years in miniaturizing the technology for blood transfusions, so that mice can be subjected to the same procedures that are commonplace in human hospitals.


The Conboy lab replaced 50% of mouse blood plasma. They got spectacular results with a single treatment, based on a lucky guess. They have not yet experimented with 30% or 70%. They don’t know yet how long the treatment will last and how often it needs to be repeated.

Evidence of rejuvenation

As with previous papers from the Conboy lab, the group focused on repair and stem cell activity as evidence of a more youthful state. Three separate tissue samples were taken from liver, muscle, and brain.

“Muscle repair was improved, fibrosis was attenuated, and inhibition of myogenic proliferation was switched to enhancement; liver adiposity and fibrosis were reduced; and hippocampal neurogenesis was increased.”

  • They measured nerve growth factors in the brain, and detected a more robust response, typical of young mice
  • They lacerated muscles and showed repair rates typical of much younger animals
  • They examined microscope slides of liver tissue, and showed that it is less fatty and striated than is typical of older mice

Figure 2. Rejuvenation of adult myogenesis, and albumin-independent effects of TPE. One day after the NBE, muscle was injured at two sites per TA by cardiotoxin; 5 days later muscle was isolated and cryosectioned at 10 µm. (A) Representative H&E and eMyHC IF images of the injury site. Scale bar = 50 µm. (B) Regenerative index: the number of centrally nucleated myofibers per total nuclei. OO vs.ONBE p = 0.000001, YY vs ONBE non-significant p = 0.4014; Fibrotic index: white devoid of myofibers areas. OO vs ONBE p = 0.000048, YY vs YNBE non-significant p = 0.1712. Minimal Feret diameter of eMyHC+ myofibers is normalized to the mean of YY [9]. OO vs. ONBE p=3.04346E-05, YY vs. YNBE p=0.009. Data-points are TA injury sites of 4-5 YNBE and 5 ONBE animals. Young and Old levels (detailed in Supplementary Figure 1) are dashed lines. Representative images for YY versus YNBE cohorts are shown in Supplementary Figure 6. (C) Automated microscopy quantification of HSA dose response, as fold difference in BrdU+ cells from OPTI-MEM alone (0 HSA). There was no enhancement of myogenic proliferation at 1-16% HSA. N=6. (D) Meta-Express quantification of BrdU+ cells by automated high throughput microscopy for myoblasts cultured with 4% PreTPE versus PostTPE serum and (E) for these cells cultured with 4% of each: PreTPE serum + HSA or PostTPE serum + HSA. Significant increase in BrdU positive cells is detected in every subject 1, 2, 3, and 4 for TPE-treated serum (p=0.011, <0.0001, <0.0001, 0.0039, respectively), as well as for TPE-treated serum when 4%HSA is present (p<0.0001, <0.0001, <0.0001, =0.009 respectively). N=6. (F) Scatter plot with Means and SEM of all Pre-TPE, Post-TPE, +/- HSA cohorts shows significant improvement in proliferation in Pre TPE as compared to and Post TPE cohorts (p*=0.033), as well as Pre+HSA and Post+HSA cohorts (p*=0.0116). In contrast, no significant change was observed when comparing Pre with Pre+HSA (p=0.744) or Post with Post+HSA (p=0.9733). N=4 subjects X 6 independent assays for each, at each condition. (G) Representative BrdU IF and Hoechst staining in sub-regions of one of the 9 sites that were captured by the automated microscopy. Blood serum from old individuals diminished myogenic cell proliferation with very few BrdU+ cells being visible (illustrated by one positive cell in Pre-TPE and arrowhead pointing to the corresponding nucleus); TPE abrogated this inhibition but HSA did not have a discernable effect.

What’s missing? They did not test any measures of physical or cognitive performance at the level of the organism.

  • Evidence of behavioral changes (learning and memory, endurance, strength)
  • Inflammatory markers
  • Blood lipids
  • Methylation clock (Horvath, UCLA) or proteomic clock (Lehallier, Stanford)

Some of this is planned for future research. Mike and Irina plan to submit tissue samples for analysis by the Horvath mouse methylation clock.


I am a committed enthusiast for the methylation and proteomic clocks that are the best surrogates we have for aging. These technologies can tell us whether anti-aging interventions have been effective without having to wait for animals (or humans) to die before reporting results. But the Conboys still regard these technologies as unproven, and they bristle at the word “clock”.  The closest they come is to catalog the entire proteome of treated mice, comparing it to untreated young and old mice.

Multi-dimensional t-SNE analyses and Heatmapping of these data revealed that the ONBE proteome became significantly different from OO and regained some similarities to the YY proteome. Supplementary Figure 4 confirms the statistical significance of this comparative proteomics through Power Analysis, and shows the YY vs. OO Heatmap, where the age-specific differences are less pronounced than those between OO vs. ONBE, again emphasizing the robust effect of NBE on the molecular composition of the systemic milieu.

Translation: As controls, they had mice that underwent plasma exchange with mice of similar age. YY were young, positive controls, and OO were old, negative controls. Treated mice were ONBE=”Old—Neutral Blood Exchange”. Rather than relying on “clock” algorithms that compute an age from the proteome, they compared the entire proteomes of test animals with those of old and young animals, and foud that they resembled the young animals more closely.

Aging and epigenetics

I was an early advocate of the theory that aging is driven primarily by changes in epigenetics. Other proponents include JohnsonRando, and Horvath. This theory is now mainstream, though its acceptance is far from universal. (The main reason people have difficulty with the idea is the question, “why would the body evolve to destroy itself?” I present a comprehensive answer in my popular book and my academic book.)

On the face of it, the new Conboy result is powerful evidence for the epigenetic theory. They have shown that there are proteins in the blood that actively retard growth and healing. Remove half theses proteins and the animals are able to grow youthful tissues and to heal better. The obvious conclusion is that, with age, there are signaling changes in the blood that weaken the animal and inhibit repair.

There are, however, other ways to interpret the changes. Aubrey de Grey has said (personal communication)

“When everything in the blood except the cells and the albumin is replaced by water, the body will definitely respond by synthesising and secreting everything that it detects a shortage of, whereas the bad stuff will not be so rapidly replaced, since by and large it was only there in the first place as a result of impaired excretion/degradation.”

The Conboys don’t embrace the programmed aging perspective, but neither is their understanding of what they see the same as Aubrey’s. The way Irina explained it to me is that the age of the biological of the body is simply a measure of how much damage has accumulated, but that cycles of epigenetics and catalysis are self-reinforcing.

“Epigenetic, mRNA, and protein are steps of one process, regulation of gene expression. And none of these steps are permanent they all actively and constantly respond to cell environment &mdash; tissue and systemic milieu…With aging there is a drift which is re-calibrated by a number of rejuvenation approaches…When an auto-inductive age-elevated ligand is diluted, it cannot activate its own receptor and induce its own mRNA, so ligand levels diminish to their younger states for prolonged time.”

The Conboys theorize that these harmful proteins are part of a positive feedback loop, in other words, a cycle that is self-sustaining

epigenetic state ⇒ gene expression ⇒ translation to circulating proteins ⇒ feedback that alters the epigenetic state

With age, the body has slipped into a dysfunctional, self-sustaining cycle, and with the shock of disruption, they are able to nudge it back into a more robust and youthful cycle, also self-sustaining.

Figure 6. Model of the dilution effect in resetting of circulatory proteome. System: A induces itself (A, red), and C (blue); A represses B (green), C represses A. A dilution of an age-elevated protein (A, at D1: initial dilution event), breaks the autoinduction and diminishes the levels of A (event 1, red arrow); the secondary target of A (B, at event 2 green arrow), then becomes de-repressed and elevated (B induces B is postulated); the attenuator of A (C, at event 3 blue arrow), has a time-delay (TD) of being diminished, as it is intracellular and was not immediately diluted, and some protein levels persist even after the lower induction of C by A. C decreases (no longer induced by A), and a re-boot of A results in the re-induction of C by A (event 4 blue arrow) leading to the secondary decrease of A signaling intensity/autoinduction, and a secondary upward wave of B (events 5 red arrow and 6 green arrow, respectively). alpha = 0.01, kc = 0.01, beta = 0.05, epsilon = 0.1, ka = 0.1. Protein removal rates from system: removalA = 0.01, removalB = 0.1, removalC = 0.01, Initial values: initialA = 1000, initialB = 400, initialC. = 700

For me, the surprising thing in Irina’s account is that there is no hysteresis in this system. The reprogramming responds to changes in the blood levels of signals within minutes. It is difficult for such a system to be homeostatic. I wonder how that can be. Life is all about homeostasis, and intuitively, we all imagine that negative feedback loops are more common than positive feedback loops. (Negative feedback loops lead to homeostasis; positive feedback loops lead to runaway, exponential change.)

Is there a clock somewhere? Is the brain special?

In the Conboy view, signals in the blood are emitted from all over the body, and not especially from the hypothalamus. If brain tissue responds in a seemingly exceptional way to proteins in the blood, it is because of selective passage of those proteins by the blood-brain barrier.

The authors remind us that in past parabiosis experiments (where blood is exchanged between old and young mice), the brain tissue of the young mice grew older but brains of the old mice didn’t get younger. This was an indication that brain aging is caused by affirmative action of “bad actors” in the plasma, and that these are able to penetrate the blood-brain barrier. This observation was part of the inspiration for the current experiments.

The corresponding procedure in humans is already FDA approved

Therapeutic Plasma Exchange (TPE) is a well-established medical procedure, and has already been performed on an experimental basis by co-author Dobri Kiprov. There is anecotal history of suggestive results, which I will write about in my next post.

Comparison with Katcher’s Elixir

This week’s announcement from the Conboys and last month’s preprint from Katcher/Horvath come from the same school of thought: that aging is coordinated through the body by signal molecules in the blood. Both demonstrated dramatic rejuvenation in rodents based on a short-term intervention, and both have plans for commercialization and human trials to begin ASAP.

So it is curious that in other ways, the programs of Katcher and Conboy are so different.

  • While both approaches are rooted in differing compositions of blood plasma between young and old, the Conboys focus exclusively on removing species that are inhibiting youthful regeneration, while Katcher’s approach is to add back the proteins that formerly kept the animal young.
  • The Conboys have fully disclosed all aspects of their experimental protocol, whereas the content of Katcher’s elixir remains a trade secret.
  • Katcher is on the fringe of academic research, and the Conboys’ lab is at one of the premier academic institutions in the world.
  • Katcher is a year further along, having experimented with different dosages and timings. Neither Katcher nor the Conboy lab has yet demonstrated life extension.
  • The Conboys demonstrate rejuvenation with wound healing, tissue structure, and renewal of nerve growth. Katcher’s claim is based on physiology (especially inflammation), cognitive performance, and methylation clock algorithms.
  • In fact, Katcher regards restoration of youthful methylation patterns as the best evidence he could offer for rejuvenation (I agree), while the Conboys are reserving judgment about the importance of methylation, and bristle at the language of a methylation “clock”.
  • Katcher understands the effects of plasma transfusions in terms of a broad theory (which I support). Aging is an epigenetic program, governed and enforced by a “clock” that operates via a feedback loop between circulating proteins that govern gene expression and gene expression that generate those proteins. The Conboys recognize they are working this feedback loop (their Fig 6) but they resist the theory that it is the essential cause of aging.

My guess is that a combination of their two approaches will be necessary for full remediation of aging, and that a combination of their resources, credibility, theoretical foundations, and contacts would be a transformative event for medical science, for biotech industry, and for biological theory. It is my fervent hope that Katcher and the Conboys might work together.