CRISPR in your Future

CRISPR is a two-year old technology developed at Berkeley, Harvard Stem Cell Inst and elsewhere, that is making genetic engineering faster, simpler, and more accurate in the lab.  Last year, they figured out how to insert and delete genes.  This year there are methods for repressing and perhaps promoting genes (epigenetically, without modifying the genome) using CRISPR-derived technology.  Enthusiasts say they will soon be able to turn genes on and off at will.  It is my belief (I’m not alone) that aging is controlled largely by epigenetics—what genes are turned on, when, and where.  Rapid progress is being made identifying the genes that need to be promoted and the genes that need to be repressed to restore an older person to younger gene expression.  It may be that by the time we are ready with this knowledge, CRISPR will be ready to implement it in living patients. The biggest question mark at this early stage is delivery.  How do you get the CRISPR protein/RNA complex into the cell nucleus?  

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The first generation of genetic engineering was turned to therapeutic use by means of genetically-modified viruses.  Viruses already know how to drill their way into a cell wall, find their way into the nucleus, then copy their own DNA into the chromosomes that they find there.  For therapeutic applications, first a replacement for a defective gene is added to the viral DNA, so that when the virus copies itself into the host DNA, the therapeutic gene will be copied along with it.  Second, the virus is denatured, crippled so that it has a limited lifetime in the host, and won’t keep multiplying at the host’s expense.  (The host is the patient.)

First-generation gene therapies are crude in that there is no ability to control where in the genome the therapeutic gene is inserted, or to turn it on or off.  Adenoviruses replaced the lentiviruses used in early trials because at least they insert the gene in the same place on the same chromosome. Results have been mixed, unexpected side-effects are common, and gene therapies have been considered only for patients with life-threatening conditions.  Nevertheless, there are about 2,000 clinical trials currently approved world-wide.

Zinc finger nucleases and TALEN are second-generation technology.  These are enzymes that contain a protein-based portion which can be engineered to bind to a specific segment of DNA, plus a snipper enzyme that cleaves DNA (both strands) where it binds.  Potentially, a gene can then be removed or inserted.  The principal disadvantages are that they are time-consuming and therefore expensive.  It is not easy to engineer a protein that reliably binds to a particular target stretch of DNA.

CRISPR technology is a candidate for third-generation gene therapy, based on a DNA-splicing protein that evolved in bacteria as a defense against invading viruses.  Viruses (bacteriophages) can infect bacteria and insert their own viral genes into the bacteria’s genome.  CRISPR-associated system protein (called Cas9 enzyme) splices the DNA at just the right place to remove the virus, restoring the integrity of the bacterial DNA.

This nifty defense evolved in bacteria and archaea, but not in animals or plants.  Now, researchers have figured out how to lift the Cas9 enzyme and the template that guides it, modify the template at will, and inject it into the cell of a human or lab animal.

(The acronym stands for Clustered Regulary-Interspaced Short Palindromic Repeats.  What that means, and why there should be little palindromes spread through bacterial DNA are questions for another day, because they don’t really help understand how CRISPR works, its potential and its limitations.)

The big new advantage is in the Guide RNA (gRNA), which can easily be sequenced to match (as a complement) any short stretch of DNA in the genome of a human or test animal.  The Cas9 splicing enzyme then finds the spot that matches the complement of the gRNA, and that’s were it does its job.  Curiously, the gRNA is not targeted as reliably as zinc finger or TALEN, and occasionally latches on to a stretch of DNA that is a near-match, so a gene can be inserted or a chromosome cleaved at the wrong place. One solution to this problem that is being tried is to prepare two gRNAs for the same stretch of two strands of the double helix, and to modify the Cas enzyme so that it only cleaves the DNA if both strands are struck simultaneously.

 

CRISPRi

CRISPR techniques can be adapted for epigenetic control, not cleaving a gene at all, not modifying the DNA permanently, but silencing a gene that we may wish to turn off.  (The “i” is for “interference” and the acronym is intended to be reminiscent of RNAi, or RNA interference, which is another second-generation technology, useful for silencing genes only.)  With CRISPRi, tags are attached to the DNA at a target location such that they interfere with transcription of a gene in progress.  Potentially, CRISPR can be adapted to promote genes as well, but this is more challenging.  It is in the promise of full epigenetic control that the most exciting applications lie, in my opinion.

 

Delivery

This is one of the big issues remaining before CRISPR technology can become a useful therapy. So far, it has been used on cells in culture. It has also been delivered intravenously at high pressure to lab mice, but the therapy only reaches a small proportion of cells.  It can be micro-injected into the cell nucleus, but this is practical only for experiments, one cell at a time.  CRISPR kits are being sold as plasmids, which is their original progeny in bacteria.  Plasmids are small loops of DNA, commonly exchanged by bacteria, but foreign to animal and plant cells.  There are papers describing adenovirus applications that combine with CRISPR to offer both control and penetration, and these are so far in early demonstration stages.

 

Active and Inactive DNA

Sewing thread is made of multiple, tiny fibers twisted together.  The twisted structure has an integrity of its own, but it’s liable to become tangled and knotted, so we keep it wound neatly on a spool until we need it.  The cell does the same thing with its DNA.  The twisted structure is the double helix.  And the DNA strand is so long that it’s liable to become tangled.  (We have about a 6-foot length of DNA in every cell, stored in a nucleus that is less than a thousandth of an inch across.)  The spools are protein molecules called histones, and threads of DNA are wound around them for orderly storage.  Each chromosome is a continuous thread of DNA, and there are many spools along its length.  At any given time, some parts of the thread are open and available, while other parts are tightly-spooled and hidden from chemical activity. Tightly-spooled DNA is called heterochromatin, and it is inactive, not available to be transcribed into proteins.  Unspooled DNA is euchromatin, and this is the active form of DNA, ready to be transcribed.

So what happens if a CRISPR unit (a Cas enzyme) comes along that is targeted to a part of the DNA that’s tightly wound up as heterochromatin?  Not much happens.  The CRISPR process is much less efficient on euchromatin compared to heterochromatin.  Imagine a reader scanning through a book looking for a particular phrase.  The process is much more likely to work if the book is open.  This is another challenge for realizing the potential of CRISPR.

 

Which genes to turn on and turn off?

I wrote a series of blog posts on this question last year.

Hormones that we lose as we age include melatonin, thyroxine, DHEA and (recently announced) GDF11

Hormones that are overexpressed, and we need to repress or block include NFκB, TGF-β and (recently announced) JAK/STAT signals

 

The Right Technology for Anti-Aging Remedies

I’m not ready to have my genes replaced, thank you very much.  I think that there are genes that are associated with longevity, and several together might add a decade or more to life expectancy.  But replacing genes is permanent, and it’s based on a technology fraught with unexpected side-effects.  Besides, my body already knows how to be young.  When it was young, it had the same genes it had now, but the epigenetics—the set of genes turned on and off was somewhat different.  I’m willing to bet that restoring a young epigenetic state to my same old genes will make me young, and that’s why I’m pumped about the CRISPR technology.

 

Read more:

Fore-Cas-t from The Scientist
Kurzweil AI on CRISPR gene therapy
Cas9 as a Versatile Tool for Engineering Biology
Comparison of Zinc Finger, TALEN, and CRISPR
Adenoviral vector delivery ofRNA-guided CRISPR
CRISPR-Cas systems for editing, regulating and targeting genomes
CRISPRi explained at a technical level
On-line discussion of speculating about use of CRISPR as a gene promoter

pf button CRISPR in your Future

Sleep and Longevity

Good quality sleep, 6-8 hours per night but not more, is statistically associated with longevity.  Is there a causal connection?  Experiments with rats and data from people doing shift work suggests that yes, there is. But how to get good sleep, and even what good sleep means varies widely from one person to the next.  Different people need more or less sleep, and different sleep schedules can work with different job schedules and life styles.  Regularity is important, and changing sleep patterns from day to day is not good for you.  Melatonin supplements can be an aid to regular sleep, and melatonin is itself a longevity hormone.  If you are one of those people who wakes after a few hours in bed, you need not fight with your body to sleep through the night.  A scheduled period of waking in the middle of the night can be part of a regular daily cycle, and you may find the midnight time is especially good for inspirational or creative activities.

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George was my partner in piano duets and also my buddy in all things concerning health and longevity.  We did yoga and meditation, jogged and cycled and gently competed, never for speed.  We discovered caloric restriction and got skinny together in the mid-1990s.  George worked nights as engineer at a TV station, and didn’t like to sleep during the day.  Some evenings he caught a couple of hours of sleep before reporting for work, some evenings he would just catch a few winks duing his midnight “lunch” break.  A few weeks past his 60th birthday, George fell asleep in front of his TV and never woke up.

I’ve learned to take sleep seriously as a longevity factor.  Just what to do about it isn’t so clear.  (And yes, TV viewing is a mortality risk independent of lack of exercise.)

Sleeping more than 8 hours per night adds 20% to mortality risk, and sleeping less than 6 hours adds 10% [ref].  The added mortality is not associated with any particular disease.

“Shift work [ref] and chronic jet-lag [ref] reduce mental acuity and increase the risk of a number of medical problems including cancer, digestive diseases including peptic ulcers, and sleep disorders.” [ref]

For some people, sleeping in total darkness helps to maintain continuous sleep.  Light is a strong trigger for depressing melatonin, and some researchers say that even the light that gets through the eyelids reduces melatonin in the blood.  Sunlight or bright blue light can help with morning wakefulness, again in some people more than others.

Melatonin is a natural hormone, available inexpensively without prescription, and used by many people to regulate sleep.  In our natural circadian rhythm, melatonin in the blood peaks at bedtime, and makes us feel sleepy.  Conversely, disappearance of melatonin from the blood precedes waking in the mornoing.  You can try melatonin at bedtime to help get to sleep, or if you’re one of those people who wakes after a few hours in bed, you can try melatonin in the middle of the night.  Mice that are given daily melatonin live longer [ref, ref].  Experiment with the dosage.  ½ mg or 1 mg is plenty for most people, and some people find that too large a dose makes them groggy the next day.  Caution: Melatonin can exacerbate sleep apnea in some people.

From WebMD:

Magnesium apparently plays a key role with sleep. Research has shown that even a marginal lack of it can prevent the brain from settling down at night. You can get magnesium from food. Good sources include green leafy vegetables, wheat germ, pumpkin seeds, and almonds. Check with your doctor before taking magnesium supplements.  Magnesium can interact with many different medications, and too much of it can cause serious health issues.”

Narcotics and alcohol can help you fall asleep, but I think they’re a bad idea, likely to make you sleepy during the day, and need more sleep in the long run.  Not recommended.  I advise avoiding even the new generation of sleep medications (Ambien, Rozerem, etc).

Caffeine can interfere with sleep if taken late in the day, and even if you take it early in the day it might it might not help your energy level in the long run.  Coffee consumption is not associated with increased mortality risk, and may even have a modest longevity benefit [ref].  But habitual consumption of caffeine causes the body to reset to a lower energy level (classic addiction response).  So I use caffeine sparingly, when I’m speaking or writing and I want to assure an enhanced level of alterness and verbal fluency, and I remain sensitive and responsive to very small hits of caffeine.

Finish eating about 3 hours before bedtime, so digestion doesn’t interfere with sleep.  A longer period of fasting before bedtime may be fine, if you are not kept awake by hunger.

 

Apnea

Fifteen years ago, I had no idea that I was stopping breathing frequently during the night until my wife noticed and alerted me.  Sleep apnea is the most common sleep disorder in the world, and increases in prevalence with age.  Statistics are soft because there are more cases unrecognized than on record.

I went in to a clinic, and spent a night there, wired up to a machine that monitored my breathing and heart rate.  I was incredulous when the doctor told me that through the parts of the night when I was asleep, I was in a 3-minute cycle, holding my breath until the CO2 buildup woke me up, gasping as I awoke, gradually calming my breathing, falling back asleep, and beginning the cycle all over.  I didn’t remember any of this, and demanded to see the recording, before I was convinced.

Much later, with focused attention as I was napping during the day, I could observe myself falling into a pattern of holding the breath until I awoke in a panic.  Apnea left me tired sometimes during the day, with occasional bouts of narcolepsy.

Long term risks of apnea include heart disease, stroke and loss of brain cells.  It’s not the oxygen deprivation that is the problem, but the re-oxygenation afterward that causes the damage.

Apnea is a mortality risk, apparently independent of obesity, with which it is strongly associated.  Fat in the neck can cause constriction of the air passage, making it more likely to collapse.  This is “obstructive sleep apnea”.  There is another flavor, “central sleep apnea”, which is unrelated to obesity or the size of the air passage, but comes instead from a failure of the autonomic nervous system.

The standard treatment for apnea, a cash cow for thousands of sleep clinics, is the CPAP machine (continuous positive air pressure), a face mask and pump that pushes air into the lungs.  Many people are helped by CPAP and find it worth the inconvenience and discomfort.  Many more can’t tolerate the CPAP.  (For me, the CPAP made my apnea worse, since I was failing to exhale, rather than to inhale which is more common.  Negative pressure “CNAP” or “INAP” (intermittent negative air pressure) machines do not exist—the acronyms are my own invention.

There are straps that hold the mouth closed and mouthguards that pull the lower teeth out in front of the top teeth.  There are suction devices that pull the tongue out of the mouth (while holding the mouth open enough so you can’t bite your tongue).  There is a surgically-implanted electrical device that stimulates the tongue to push forward at the appropriate point in the breathing cycle.  All of these work for some people.

Further out therapies for apnea include Buteyko breathing, orofacial myofunctional therapy, and singing melismas The latter even has some data behind it.

I’ve kept my apnea under control by re-training myself not to sleep on my back.  It helps, but is not a complete solution.

Tension and anxiety

Some sleep problems are extensions of day problems—anxiety, depression, ennui, overstimulation, work pressures.  These are often better addressed by life changes than by therapies.  But relaxation practices can help: yoga asanas and breathing, meditation, biofeedback, heart rhythm coherence, Alexander technique, martial arts.  Vigorous exercise and time outdoors helps with every aspect of health, longevity, mood, relationships, productivity, creativity…and sleep, too.

Learning to relax has benefits that go well beyond improved sleep.  Many people find that through self-hypnosis or mental relaxation, yoga or meditation techniques, they can relax at night and feel fully rested even on nights when sleep may be elusive.  These same techniques are good for the “power nap”, when a brief submersion of 10-30 minutes can precipitate a boost in alertness, productivity and good humor.

 

Two-phase Sleep

In 1979, I was fortunate to be acquainted with Bryn Beorse, then in the last year of his life, but productive, healthy and quietly charismatic at age 84.  I knew him as a UC Berkeley engineering prof and lifelong advocate of renewable energy from the ocean.  But he was also an unlikely guru, with a small but loving following of meditators and Sufi practitioners.  Bryn told me that his habit and practice was to awake about 1AM and do an hour or two of Sufi exercises and meditations before returning to sleep out the night.  This and other things he said made a lasting impression on me.

Much more recently, I have learned how common it is for people to sleep in 3-4 hour cycles rather than 6-8 hours.  Some say that before the Industrial Revolution, bi-phasic sleep was part of the culture.  A period of wakefulness in the middle of the night is part of the body’s natural rythm for many of us, and if it is so for you, I suggest you might adapt to it rather than fight it.  Use the waking period for something nourishing, sustaining and relaxing.  Yoga or meditation are ideal.  You can read something inspirational, practice singing or playing music, listen to music that contributes to your wellbeing.  For some, it can be a creative time, writing or painting or composing, but I don’t recommend using the time to extend your work day or answer emails.  Creative play is an alternative, but video games less than optimal.  When you feel the first wave of sleepiness return, don’t hesitate to go back to bed.

It’s not so common in America, but through much of Asia and South Europe, mid-day siesta is part of the culture.  People sleep less at night, and nap after lunch.  The right to a two-hour lunch break is written into the Chinese constitution.

Some studies show that sleeping twice a day is more efficient than sleeping once, but the decision will be based on your metabolism and your daily schedule.

 

Bottom line advice

I encourage you to experiment, with the goal of finding a schedule that works best for you.  Check magnesium levels, especially if you have muscle twitches.  Don’t hesitate to take melatonin at bedtime, but avoid sleeping pills.  The body’s biorhythm adapts to a regular pattern, and disruption of that rhythm can be costly.  Good sleep contributes to everything you value about life (as well as its length): alertness, creativity, patience and good humor, productivity, enjoyment and a depth of wellbeing that comes from connecting the inner and the outer life.

pf button Sleep and Longevity

Transfusing Youth: the epigenetic aging clock hypothesis is about to be tested

Just this past Spring, Tony Wyss-Coray of Stanford demonstrated that infusions of blood plasma from young mice can make old mice grow new brain tissue.  Others have demonstrated benefits for muscle and liver health. The old mice are healthier, smarter, better healers for the infusion of hormones and dissolved factors (not blood cells) from the younger mice.  Leapfrogging over years of animal tests and investigations, Wyss-Coray is about to test plasma infusions in people.  

(I’m grateful to Adrian Crisan and a reader who identifies himself only as “Quandry” for alerting me to this story.  This is not what I had planned to write about today, but I’m pumped.)

 

I have argued that much of our age-state may be coded in gene expression—the choice of which genes are active and which are idle.  We go through life with the same 46 chromosomes we got from our parents, the same DNA, the same genes.  But different genes are turned on and off  in different tissues, at different ages.  This is “epigenetics”, and it determines everything about a cell’s behaviors and activities.

The epigenetic state of a chromosome is programmed by several different kinds of decorations to the DNA.  The decorations include methylation, acetylation, and states of tight-winding and unwinding of DNA about molecular spindles called histones.

Does epigentics also determine age?  In other words, would a young person whose DNA state was epigenetically re-programmed to look like an old person’s actually become old?  Could the body of an old person fix itself up to look like that of a young person if its DNA was reprogrammed?  I think it’s a good bet that this will work.

A separate question is whether it works by a local or a whole-body mechanism.  Does changing the epigenetic programming of a single cell make that one cell younger, or does it contribute to a hormone environment that makes the whole body a tiny bit younger?  DNA expression creates proteins that do the cell’s work at home within the cell, and others that circulate through the body as signals, commonly known as “hormones”.  Hormones can affect the decoration of DNA, changing the epigenetics.  But hormones are also a product of epigenetics.  Cause, effect, and cause and effect.  Perhaps this is the basis of a clock, a biological clock that can time development, maturity, puberty and aging.  It’s an idea I find intriguing.

Up until Sunday, I thought that this idea would be explored at a leisurely pace, indirectly as a result of research with a different conceptual basis.  I was delighted to learn from this New Scientist article of trials soon to begin that will test to what extent young hormones can make a person young.  Here is an interview with Wyss-Coray that contains more details.

History of Parabiosis and Plasma Transfusions

About ten years ago, Tom Rando and several students at Stanford picked up and rejuvenated an experimental paradigm that had been used and abandoned in the past.  They sewed together a young mouse and an old mouse so that they shared a common blood supply.  [See my previous blog, and another].  Of course, the arrangement was hard on both mice, and they didn’t live long.  But they lived long enough to determine that the older mouse was receiving benefits from the younger blood:  faster healing, tissues that looked younger under the microscope, enhanced growth of new nerve and muscle cells.

There were many directions to take this research:

  • What were the blood factors that gave the benefit?  (Not just beneficial blood factors, but others as well that we have too much of as we age.)
  • What tissues and processes are affected?
  • Aside from the surgery, what are the costs and risks?
  • The big question: does the youthful blood profile have the power to reprogram cells epigenetically, so that the body remains in a youthful state and produces its own youthful blood profile?

 

Wyss-Coray’s Bold Experiment

Plasma transfusions are old technology.  Donor blood is separated centrifugally (apheresis) into cells and liquid (plasma) and the cells are returned to the donor’s body.  Because there are no cells, there is no issue of blood type compatibility or immune attack.  A lot of the usual regulatory hurdles are avoided, and Phase I safety studies are bypassed.

This is a small trial, less than 20 Alzheimer’s patients, conducted at Stanford but privately funded by Alkahest, Inc.  (I can’t find a web site for them.  Perhaps they are very new.)  It sounds from the article as though they plan on only one transfusion for each patient.  They will measure cognitive performance sensitively, and hope to see a bump in a few days, perhaps lasting a few weeks or months.

If it is true that they’re planning only one transfusion, this is disappointing.  I’m tempted to say something stronger than “disappointing”, like “what could they be thinking?”  They’re not giving these patients new brain cells, after all.  They’re signaling the body in a way that is likely to stimulate growth of new cells and offer other benefits as well.  But this could take weeks or months, and require a youthful hormonal environment that is sustained over that time.  If I were designing the experiment, I would opt for 10 weekly transfusions to 2 patients, rather than a single transfusion for each of 20 patients.

 

The Future of Blood Factors

I predict that Wyss-Coray’s experiment will work marginally or not at all without repeated treatments.  I hope they see enough success to warrant extended trials in a follow-up.  I think that with ongoing treatment, it has the potential to work spectacularly well, and that over a few months’ time we will see patients becoming younger in a number of ways.  If this happens, it will precipitate a rush of interest and new research in the area.  Patients, too, will be clamoring for treatments.  Old people will feel an entitlement to the blood plasma of young donors.

We will quickly run out of donors.  The best thing that could come from this is an intensive effort to test different components of the blood that vary with age.  I predict that the optimum blood environment will be obtained by re-balancing components.  rather than just adding a few magic ingredients.  Some hormones will have to be dialed up, others dialed down in order to make old blood young.  We may hope that there are just a handful of important factors, and not many hundreds or thousands.  It will not be terribly difficult to create the recipe once we know which hormones are the important ones and how much to add or remove.

 

pf button Transfusing Youth: 
the epigenetic aging clock hypothesis is about to be tested

Notes from Rejuvenation Biotech Conference

San Jose Aug 21-23

Herbal Telomerase Activators

As far as I know, Product B is the best commercial telomerase activation product.  (For background read this blog entry.  All currently available telomerase activators are inadequate, and they may have only nominal effect – we don’t know.)  Product B is manufactured by Isagenix, based on cell culture testing at Sierra Sciences.  Sierra screened hundreds of herbal products, reporting their results to Isagenix in black-box mode, blind to what they were testing.

I now believe that the lowest-level ingredients in Product B (last on the list) are more potent than the highest-level ingredients (first on the list).  For the last nine months, I have been supplementing with the first four herbal ingredients in Product B: Silymarin, Ashwagandha, Horny Goat Weed and Bacopa.  I plan to look into the last six ingredients:  Boswellia, Maca, Hawthorn, Harada, Shilajit and Chia seed extract.    Complete list of ingredients here.

Note that there are no extracts of astragalus in Product B.  I have contradictory information about whether cycloastragenol is a telomerase activator.

 

CRISPR

George Church of Harvard’s Stem Cell Institute led the conference off with a summary of progress in CRISPR technology.  I had never heard of CRISPR until last year.  As of last year, it was a way to gain more control in genetic engineering.  A protein could be engineered to seek out and bind to a specific spot on a specific chromosome, so that the experimenter could now specify where in the gene would be inserted.

Well, that was so last year.  Now the protein has been replaced with an RNA sequence that can be specified as an exact complement to the particular region of DNA that is targeted.  Easier, and more reliable.  And – this is the biggest news of the conference – CRISPR can now be married to a gene promoter or repressor, so that particular genes can be turned on and off using CRISPR.  This is possible not just in cells but in living organisms, potentially in you and me.

It is my belief that aging is controlled to a great extent by gene expression.  Young gene expression creates a young body.  Our bodies know how to be young, if we instruct them to do so.  Well, we now have the language to tell the body to be young.  We also have a good selection of genes to start with, genes for hormones that we have too little or too much of as we age.  What are we waiting for.

A questioner asked George about interaction with “chromatin state”.  In any given cell, at any given time, some of the DNA is unwrapped and available for expression, called euchromatin, while the rest, called heterochromatin, is spooled around protein spindles (histones).  George indicated that the CRISPR technique works a lot better on euchromatin than on heterochromatin, as we would expect, but that it works some even on heterochromatin, and we’re learning rapidly.

CRISPR is a very new technology, still in the explosive stage of development, and I promise to write a full post about it soon.

 

Ecological consequences of longevity

Caleb Finch, who wrote the book on genetics of aging more than 20 years ago, still carries an encyclopedic knowledge of research in the field.  At RB2014, he placed aging and anti-aging in the context of human imact on the environment and environmental impact on humans.  Anti-aging leads to population growth, unless we can couple it with reduced fertility.  Population growth leads to habitat loss, species extinctions, and loss of biodiversity.  Population density also contributes to pollution, which can accelerate aging.  Particulate pollution, associated with diesel engines especially, accelerates amyloid deposits and cognitive decline.  Air pollution also exacerbates heart disease. Alzheimer’s Disease has been increasing steadily the last 40 years as heart disease has been in decline.

 

Cell Signals

I learned from Judith Campisi that senescent cells send out signals that potentiate cancer, and from Evan Snyder that stem cells send out signals that promote growth and health of cells nearby.  Yea, stem cells!  Boo, senescent cells!  Only recently, it had been thought that senescent cells were merely slackers, no longer able to perform their function, but it turns out that they emit signals that have a negative systemic effect as well.  Only recently, it had been thought that healthy stem cells were able to repair and rebuild damaged tissue, but it turns out that they emit signals that have a positive systemic effect as well.  These are global signaling properties that are just coming into focus.

 

GDF11

Brock Reeve of Harvard Stem Cell Institute gave us an update on recent work on the signal protein called GDF11 (for Growth Differentiation Factor), which circulates in the blood.  We have less GDF11 as we get older.  Just this spring, two article came out in Science which demonstrate that GDF11 can stimulate growth of new neurons and muscles.  Last year, it had been reported that GDF11 also can reverse damage to aged hearts.  It may be impractical to administer GDF11 intravenously as a systemic rejuvenating factor, but the race is on to discover promoter treatments that enhance expression of our native GDF11 gene.

Skepticism from the conference organizer

I found it ironic that Aubrey de Grey, whose SENS Foundation sponsoted the conference, expressed skepticism about this whole approach to aging.  He sees aging as a matter of accumulated damage rather than perverse signaling, and he imagines that epigenetic changes that happen with age are actually evolved for the body’s benefit.  He distinguished systematic epigenetic shifts with age, which he thinks are beneficial, from random epigenetic drift, which he thinks is detrimental.

Stem cell therapy for heart disease

Linda Marban of Capricor Inc in Los Angeles reported on research to cells from the patient himself, treat them in vitro to turn them into stem cells, grow the stem cells in a petri dish, and then inject them into the patient’s heart, where they can repair damaged tissue.  The technology was described several years ago in this Nature article.

 

Stem cells to treat Parkinson’s Disease

Stephen Minger reported on the potential for applying this same technique to teat Parkinson’s Disease.  Foetal stem cells have already been used with some success, though, of course, they tend to be rejected by the patient’s immune system.  Using induced pluripotent stem cells (IPS cells) derived fromt the patient’s own cells should solve this problem.  It is now known that the brain already contains stem cells, and that in cases of stroke and brain traum, stem cells migrate to the site of the damage and activate to repair the damage.  Minger speculates that new nerve cells might be routinely required in order to form new memories.

OVERALL, I had the impression that there are now significant anti-aging technologies poised to move out of the lab and into testing and marketing.  Funding issues, marketing, regulation and logistics will impose frustrating delays.

 

pf button Notes from Rejuvenation Biotech Conference

FDA Questions an Aspirin a Day.   I Question FDA.

For 25 years, daily aspirin for people over 50 has been standard advice from the medical profession.  A few weeks ago, the FDA changed its tune, and now recommends daily aspirin only after your first heart attack.  I’m sticking with the classic advice.  Aspirin is an anti-inflammatory with benefits that include lower risk of dementia and some cancers.  The overall reduction in death and disease adds the equivalent of about 2 years of life. Though aspirin causes stomach irritation in some people, you will know quickly if you are one of them, and can try a different NSAID.

What changed?  What were they thinking?  Although the FDA policy change has been widely publicized and there are several new consumer information pages, I have been able to get no information from them about the primary literature on which they relied.

Reading between the lines, I find hints that the decision was based narrowly on the benefit of avoiding fatal heart attacks vs the cost of stomach bleeding and ulcers.  I see no evidence they considered the benefits of aspirin in lowering cancer risk or Alzheimer’s risk.  And I suspect that in evaluating the heart benefits, they were looking only at the anti-coagulent effect (short-term) and not the anti-inflammatory effect (long-term).  (I wrote about the difference last year.)

According to Robert Temple, M.D., deputy director for clinical science at the Food and Drug Administration (FDA), one thing is certain: You should use daily aspirin therapy only after first talking to your health care professional, who can weigh the benefits and risks.
–  FDA Consumer Updates

If “one thing is certain,” it is that this advice is motivated by legal and not medical considerations.  How many of us are lucky enough to have a family doctor or GP who keeps up with the literature and drills into the statistics? If today’s doctor had time for such things, his employer would jack up his patient load.

Without seeing the basis for the decision, I can think of only two reasons they might lean in this direction.  First, there is a tendency toward “natural medicine”, or trusting the body, or erring on the side of non-intervention.  I have argued that this is appropriate in young patients, but that you can’t “trust the body” with respect to diseases of old age.  The body is not trying to optimize health; it is programmed to die; so there should be no presumption against intervention.  Second is the really cynical possibility that aspirin is not a money-maker for anyone, and damping aspirin prescriptions will increase pharmaceutical profits on statins and other expensive drugs.

Dr Mercola devoted a column to the FDA decision last week.  While I respect Dr Mercola and frequently look to him for ideas and leads, I think that in this case he has made a mistake.  He lists seven of the studies with worst outcomes, and I don’t think he characterizes them fairly.  I can only guess that Mercola has fallen for the natural anti-aging fallacy.

Study Mercola’s take-home My reading of the same article
American Heart Journal 2004 (WASH) Patients receiving aspirin treatment showed the worst cardiac outcomes, especially heart failure This study compared short-term results only for aspirin compared to more powerful anti-coagulants that are too dangerous to use long-term. All subjects had had a previous heart attack. Differences among the groups were insignificant due to small study size.
New England Journal of Medicine2005 Ten-year study at Harvard involving nearly 40,000 womenfound no fewer heart attacks or cardiovascular deaths among women receiving aspirin therapy Actually, there were 9% fewer heart attacks among women taking aspirin, but this was not statistically significant because the subjects were primarily younger women, so there were few heart attacks in either group.
British Medical Journal 2009 Aspirin therapy for diabetics produced no benefit in preventing cardiovascular events In a meta-analysis of 6 studies, aspirin produced a 10% reduction in heart attacks, but it was not significant because of sample size.
Pharmacoepidemiological Drug Safety 2009 Swedish researchers studying individuals with diabetes found no clear benefit for aspirin, but did note it can increase the risk of serious bleeding Younger diabetic patients who took aspirin had so many deaths from bleeding that it exceeded the benefits in terms of heart disease. For older diabetic patients, the lives saved from heart disease exceeded lives lost to bleeding.
Journal of the American Medical Association 2010 Scottish study found that aspirin did not help prevent heart attacks or strokes in healthy, asymptomatic individuals with a high risk of heart disease 6% reduction in deaths from all causes was not significant because of small sample size.
Journal of the American College of Cardiology 2010 Patients taking aspirin showed a higher risk for recurrent heart attack and associated heart problems My interpretation is that subjects taking aspirin had their first heart attack 4 years later than others, and as a result their second heart attack was more likely.
Expert Opinions in Pharmacotherapy 2010 British meta-analysis of 7374 diabetics concluded that aspirin does not lower heart attack risk 4% reduction in mortality and 10% reduction in heart attacks was not significant because of small sample size.

 

Results from more positive studies

There have been many studies with positive outcomes.

This meta-analysis 2002  covered 287 studies with 135,000 total patients, and overall cardiovascular risk reduction was found in the range 30%, with 17% reduction in mortality.

This meta-analysis (2003) covered 9 studies of Alzheimer’s disease, and found among subjects who had been taking NSAIDs more than 2 years, the risk was down 73%.  That is not a misprint,  Among subjects taking aspirin, the risk of Alzheimer’s was only ¼ as big.

This meta-analysis (2012) looked at cancer risk and found 25% fewer cancer cases, 15% lower cancer mortality with aspirin.

Just this week, Nicholas Bakalar, writing in the NYTimes reported on a new meta-analysis:

The analysis, published online in Annals of Oncology, found strong evidence that aspirin reduced the risk for colorectal cancer, and good evidence that it also reduced the risk for esophageal and stomach cancers. There were smaller or more variable effects for protection against breast, prostate and lung cancers.

They also found that long-term use was required. In controlled trials, there was no benefit until at least three years of use, and mortality was reduced only after five years. A “baby aspirin” of 75 to 81 milligrams was sufficient, and there was no evidence that larger doses provided added benefit.

 

Bleeding as a side-effect

A small number of patients have trouble with bleeding and upset stomach, and it is easily determined whether you are among those.  If so, stop taking aspirin.  The number of heart attacks and cancer cases prevented may also be a small number, but there is no way to know in advance, and I say, if the aspirin isn’t hurting you, take your chances.

 

History – How did we get here?

Use of willow bark to relieve pain goes back at least to the Egyptians 3,000 years ago. Native American shamans used willow for fevers and headaches.  The aspirin molecule was first isolated in the mid-19th century, and synthesized (by Bayer) before 1900.  It became the world’s largest-selling analgesic, and has been so ever since.

In the 1960s, biochemical knowledge was still rudimentary, and heart attacks were conceived as a plumbing problem.  Arteries to the heart become clogged and blood flow is impeded.  Doctors knew that the clogging was exacerbated by the tendency of blood to clot around the fatty deposits that were causing occlusion.  So it seemed that anti-coagulants (blood thinners) should lessen the risk of heart disease in the short term.  Aspirin was known to be a blood thinner, and assumed to be safe based on its long history.

Beginning in 1971, Peter Elwood and John O’Brien began the first trial of aspirin to see if it would reduce the risk of heart attacks.  Early results were positive, indicating a short-term benefit.  Early adopters were taking daily aspirin in the 1970s and as experience accumulated, statistics made a convincing case that they were having fewer heart attacks.  By the late 1980s, use of daily aspirin to lower risk of heart disease became a standard medical recommendation.

The justification for daily aspirin at the time was based entirely on statistics.  It was assumed that the benefit came from aspirin’s anti-coagulant activity.  “Inflammaging” was still in the future, but the idea that heart disease was associated with inflammation in the artery wall was just being explored.

It is only in the last fifteen years that perception of how aspirin works has shifted.  Aspirin is an anti-inflammatory agent, the prototypical non-steroid anti-inflammatory drug (NSAID).  Inflammation is associated not just with heart attacks and ischemic stroke, but also with cancer, arthritis and Alzheimer’s disease.  Daily aspirin is associated with lower incidence of all these diseases.

The long-term effects of anti-coagulants on heart attack risk proved to be complicated.  But anti-inflammatory action is the most reliable strategy we have at present for reducing risk, not just of heart disease but of all the diseases of old age.  Because of shakey ideas about blood-thinning and heart attacks, millions of people were advised to take daily aspirin.  Decades later, it was discovered that these people had lower rates of heart disease, dementia, stroke, and cancer, because of the fortuitous happenstance that aspirin is also an anti-inflammatory agent.

Incidentally, all of the five anti-inflammatory agents I listed are also blood thinners (aspirin, ibuprofen, naproxen, fish oil, curcumin).  I don’t know enough biochemistry to understand why the two should be related.

 

Is aspirin better than other anti-inflammatory supplements?

Comparison with ibuprofen and naproxen has been done, but asking only a limited set of questions.  Compared to ibuprofen, aspirin is a little more likely to irritate the digestive tract, but less likely to damage the liver.  Compared to naproxen, aspirin is not as strong, but safer.  I have not seen a comparison with fish oil or curcumin.

It should be possible to define a strength of anti-inflammatory effect, and compare different agents, but I have never seen even that done.  Of course, what we would like to see is controlled, long-term human epidemiological studies comparing effects of all five anti-inflammatory agents on four major disease outcomes (cancer, heart attacks, stroke and Alzheimer’s).  Data does not yet exist for such a study.

 

Why is there so much difference from one study to the next?

Studies of aspirin are not unusual in this regard.  This is a great unanswered question, not just in epidemiology but all through the life sciences.  Even after accounting for placebo effect and biases in perspective from one investigator to the next and differences among sample populations, there is a lot more disparity in outcomes than we can explain.  That’s life.

 

My advice

My bottom line is that most people over 50 can benefit from daily aspirin or ibuprofen, as it lowers risk of cancer, dementia, and arthritis as well as heart disease and stroke.  Diabetes patients might start a few years later. I would suggest that if you have stomach or bleeding issues with aspirin, you will know it, and stop taking it.  If you have a family history of hemorrhagic stroke, don’t mess with aspirin at all.

 

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Love, Death, and Oxytocin

Oxytocin, the “love hormone”, is one of those blood factors that we have less of as we age. A recent study connects loss of oxytocin with frailty and loss of muscle mass in old age. Could it be that oxytocin is the biochemical mediator that signals the body to live longer in response to loving connections and caring behaviors?

 

The body knows how to be young.  It had no trouble being young X years ago.  Now the body is choosing to be old, slowing down its repair and re-building functions, gradually destroying itself with inflammation, eliminating nerve and muscle cells via apoptosis.  In doing this, the body is following hormonal signals that circulate in the blood.  If the hormonal signals say, “old”, then the body is old; and if the hormonal signals say “young”, then the body will respond appropriately.

This is my premise about what aging is, how it works, and how it can be addressed medically.  (Not everyone thinks this way ─ but you already know that.)  I call it the “epigenetic theory of aging”, and I’ve blogged about it here and written more technically here.  Last summer, I listed some of the hormones that we don’t have enough of in old age, and some that we have too much of.

 

Oxytocin is a Stem Cell Signal

Oxytocin levels decline with age, and this summer, there was an article in Nature suggesting that it may be one of those signals that help to keep us young.  Aging mice with extra oxytocin retained muscle mass that was lost by mice of similar age as their oxytocin naturally declined. Oxytocin signals the muscle stem cells (aka satellite cells) to actively divide and make more muscle cells.  The study’s authors note, however, that the satellite cell receptor for oxytocin also declines with age, so that the problem of muscle loss is really compounded, and may need to be addressed at both ends.

The reduction in muscle mass in humans starts in the third decade of life and accelerates after the fifth decade, resulting in a decrease in strength and agility. Muscle ageing is characterized by a deficiency in muscle regeneration after injury and by muscle atrophy associated with altered muscle function, defined as sarcopenia. The limiting step in muscle regeneration after injury is the activation of the muscle stem cells, or satellite cells…Satellite cells from old muscle are intrinsically able to repair damaged muscle, but are reversibly inhibited by the aged niche, yet can be quickly rescued for productive tissue repair by a number of experimental methods, including heterochronic parabiosis. While the rejuvenating effects of heterochronic parabiosis have been observed in several tissues such as muscle, brain, liver, pancreas and heart the molecular mechanisms are not fully understood and…to date, few circulating molecules decreasing with age have been identified to be responsible for skeletal muscle ageing.

 

Other roles of oxytocin

Oxytocin is known for several other functions.  It suppresses our fear and protectiveness. Delivered intraveinously to women in labor (as Pitocin) it helps to strengthen contractions.  It is also thought to be related to bonding between parent and child, between lover and lover.  In popular literature, it is referred to as “the love hormone”, with some justification.  But it doesn’t necessarily make us feel good or improve our judgment; rather it shifts our feelings in the direction of more trusting, less self-protectiveness, more caring, with results that can be good or bad depending on circumstances.

Oxytocin is released in the body in response to physical touching and especially during sexual orgasm.  Massage often triggers oxytocin.

 

What is “heterochronic parabiosis”?

The research comes from the lab of Irina and Mike Conboy, who have pioneered work in “heterochronic parabiosis”.  This is an experimental setup in which an old mouse and a young mouse are joined surgically, like Siamese twins.  It has been noted that the admixture of young blood promotes wound healing and nerve growth in the older mouse.  This raises the promise of a possible path toward rejuvenation, but the experimental technique must be refined in order to answer the obvious questions

  • Can the old mouse be rejuvenated in general, systemic ways?
  • Is its life expectancy affected by addition of young blood?
  • What are the blood factors reponsible for the effect?

The Conboys are already well into the next phase,

  • designing ways to infuse blood into a mouse without the trauma of Siamese surgery, and
  • separating different hormones in the blood so they can be tested individually and in combination.

They and other researchers have concluded that it is not the red blood cells or the white blood cells, but rather the blood plasma that carries the benefit.  Blood plasma contains many dissolved hormones, sourced from all the body’s internal secretion organs.  Some are up-regulated with age, and some are down-regulated.  The hypothesis is that there is not one magic hormone that makes us young, but rather it is the quantitative balance of various hormones that signals the age state of the body.

 

You heard it first on the Aging Matters blog

I’m going to go out on a limb and suggest a theoretical hypothesis that might help to inspire and direct future research:  It is well-established that social connectivity is a predictor of longevity in humans.  But the mechanism is unknown by which social factors affect individual life span.  Perhaps oxytocin plays an intermediary role, signaling the body in response to social connection, and promoting longevity.

There is a whole branch of aging literature relating social factors to aging and mortality.  People who are more connected have lower death rates.  Sexual activity, too, has been linked to longevity, especially in men.  Married women and especially men have lower mortality rates than un-married or divorced people. People with regular volunteer activities have lower mortality rates than people who devote all their energy to pleasing themselves, after adjusting for health and mobility factors.  More money is associated with longer life, and independently, careers with more responsibility lend to longevity [British Whitehall Study].

In all these areas, it is especially difficult to disentangle cause from effect. You can’t very well randomly assign people to two groups and ask the first group to make passionate love with a standardized partner twice a week, while the second group gets equivalent exercise from walking.  Even more difficult would be to conceal from the experimental subjects (until the experiment was over) to which group they had been assigned.

In this context, understanding biochemical mediators can help to guide research and design experiments.  We should be working toward an integrated view of human health that looks upon chemistry and behavior as two lenses for viewing one underlying reality.

 

Oxytocin’s uses, present and future

Here is Dr Sahelian’s page on oxytocin.

Oxytocin has long been available as an intravenous medication used for women in labor.  More recently, there is a nasal spray that is finding intriguing applications for autism.  Experimental use of oxytocin for enhanced intimacy or sexual experience has had mixed results.  Whether it can find a role in longevity treatment is something we should know within a few years.

We look forward to the day when we can self-administer convenient doses of oxytocin and maybe enhance oxy-receptors as well.  Until then, I guess we’ll just have to make do with massages and orgasms.

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Adapt or Die => Die Sooner to Adapt Faster

In the long run, the ability of a species to evolve is more important than anything else in determining its competitive success.  This is true almost by definition: given enough time, the ability to adapt and improve will overtake any initial disadvantage.

But evolutionary theory these last 50 years has been quite skeptical of “in the long run”.  If it is driven to extinction because of a competitive disadvantage in the short run, then what matters if it has the potential to improve, eventually?

This has everything to do with aging.  A population with aging has more diversity and a faster turnover compared to a similar population in which death is only due to famine, predators, disease, etc.  So – in theory – a population with aging evolves more rapidly than a population that doesn’t age.  But “the long run” can be thousands of lifetimes, and in the meantime those individuals that die early (of aging) are at a competitive disadvantage compared to those who continue to live, and have that much more time in which to produce offspring.

Can an aging population resist invasion (by longer-lived competitors) and cohere long enough that its superior rate of adaptation turns into a decisive advantage?  This is the question that has been at the center of my research the last dozen years.  On the one hand, there is abundant evidence that aging is no accident, that it has evolved via natural selection that explicitly favors aging.  On the other hand, the theoretical argument casts doubt on the scenario where aging is selected on this basis.

The best resolution I have been able to find for this paradox is that aging has been able to evolve on this basis, and it is because the short-term advantage of unrestrained reproduction has been held in check by a different, faster-acting evolutionary principle than evolvability. Unrestrained reproduction leads to population overshoot, population crash, and extinction. This is a powerful, fast-acting evolutionary force, and populations have had to adapt by tempering individual competitiveness.  This has created an environment in which the long-term advantage of aging is relevent, and aging as a population-level adaptation can thrive on this basis.

Here is a press release for an article of mine that will appear next month in American Naturalist, demonstrating mathematically how aging might be able to evolve, despite its individual cost, based on increased evolvability at the population level.  (The cartoon is by my daughter, Maddy Ballard.)

DinoCartoon32 Adapt or Die => Die Sooner to Adapt Faster

Young Orville was given to flights of fancy, and seemed to show no interest in securing a future.

Among members of the educated public, two views of aging predominate: One is that living things wear out like machines, suffering damage that accumulates over time. The other is that aging and death are programmed into the genes to assure space in the niche for the next generation to grow up.

But both these theories were discredited more than 100 years ago. As to the first, physicists say, “That’s not the way entropy works.” Concerning the second, evolutionary biologists will tell you, “That’s not the way natural selection works.”

So among specialists in evolutionary theory, there is a third theory: Aging did not evolve directly, but rode the coattails of genes that promote fertility early in life. In this paper, two physicists challenge the evolutionists, with a model that demonstrates how “making room for the next generation” might be a viable selection mechanism after all.

Of course, the fact that the model works this way does not imply that nature works this way. But the authors argue that their model explains recent genetic data much better than the standard theory, which was formulated before the modern science of genetics.

“Many genes that cause aging have now been identified in a number of species grown in the lab,” says Josh Mitteldorf, the paper’s lead author. “Most of these genes have nothing to do with fertility,” contradicting the mainstream evolutionary theory. “Some of these aging genes have ancient roots, going back to the first protozoa, a billion years ago. Any trait that has stuck around so long must have an adaptive function.”

“Aging is a classic case of a conflict between the individual and the community,” says author André Martins. “Going back to the 1960s, the evolutionists have a belief that in such conflicts, it is always the individual interest that prevails. Our model shows otherwise.” In recent years, computer models have played a central role in the rehabilitation of “group selection”, and both the authors have previously published computer models in which aging is able to evolve because the group benefit trumps the individual cost. Read the Article

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