Tag Archives: circadian rhythm

Epigenetics & Circadian Biology: Prader-Willi

I came across a recent study on a mouse model of Angelman Syndrome (an epigenetic disorder), and wasn’t surprised to learn there’s a strong circadian component to it.  Epigenetics are one of the main ways circadian rhythms are programmed.

In this case, the circadian connection is more direct.

Angelman Syndrome (AS): you inherit 2 pairs of each gene, one from Mom and one from Dad.  In some cases, one of the copies is silenced via epigenetics and you’re basically just hoping the other one is in good shape.  In the genetically relevant region in AS, the paternal copy is silenced and the maternal copy does all the heavy lifting, but in AS, the maternal copy is mutated or absent, so none of the genes in this region are expressed.

Interestingly, scientists found that one of the genes, Ube3a (an ubiquitin ligase), is involved in regulating Bmal1, a core circadian gene (Shi et al., 2015) . And mice with a silenced paternal Ube3a and mutant maternal Ube3a exhibit many of the same circadian symptoms of children with AS. They don’t mimic all of the symptoms as there are many other genes in this region.  But both show circadian abnormalities.

Prader-Willi Syndrome (PWS) is the epigenetic opposite: same region of DNA, but silenced maternal copy and mutant or absent paternal copy. This disorder is characterized by massive obesity and low muscle mass (among other things).

Prader-Willi

While reading about this disorder, I was taken aback with how the obesity was explained.

“Insatiable appetite” (Laurance et al., 1981), although from what I can gather, these children would develop massive obesity even if they were fed cardboard.  Some studies even showed no change in food intake and/or energy expenditure (eg, Schoeller et al., 1988), which led some researchers to publish entire papers about how these children must be lying and/or stealing food (eg, Page et al., 1983) .

Further, other researchers even explained their obesity was due to an inability to vomit (Butler et al., 2007).

THEY’RE OBESE BECAUSE THEY’RE NOT BULEMIC.

AYFKM?

When these kids gain weight, it’s nearly all fat mass; when they lose weight, it’s nearly all muscle [shoulda been a BIG hint]… this even led some researchers (who detected no change in fat mass after significant weight loss) to conclude that their techniques to assess body composition must not be valid in this population because: surely, they must’ve lost some fat mass like normal people do.

THEY FAILED TO CONSIDER THIS IS AN EXTREME CIRCADIAN MISMATCH DISORDER IN NUTRIENT PARTITIONING

It was actually painful to read: these kids are being accused of stealing food and not vomiting because that’s the only way to explain it.

NO IT’S NOT, SCIENCE.

They can be forced into losing fat while maintaining some muscle with an extreme protein-sparing modified fast (eg, Bistrian et al., 1977)…

A few research groups have considered the possibility it’s a hormonal disorder, and some fairly long-term studies with GH replacement have shown promising results (eg, Carrel et al., 1999).

Prader-Willi Food Pyramid. Wait, wut? O_o

Prader-Willi Food Pyramid.
Wait, wut?
O_o

Some have even speculated involvement of leptin (eg, Cento et al., 1999), although this hasn’t been followed-up on.

Disclaimer: I don’t know the cure or best treatment modality for Prader-Willi, although given the strong circadian component in its sister condition, Angelman’s Syndrome, I strongly believe this avenue should be explored (in combination with the seemingly necessary hormonal corrections, which have been the only successful interventions yet).  “Diet” doesn’t work; these kids aren’t obese because they’re stealing food or failing to vomit.  Interventions strictly targeting CICO have massively failed this population.

Side note: in the Angelman Syndrome mouse model, *unsilencing* the paternal copy worked… maybe the same could work in PWS (and/or other forms of obesity)…?

Evidence supporting potential circadian-related treatment modalities for PWS:

A Prader-Willi locus IncRNA cloud modulates diurnal genes and energy expenditure (Powell et al., 2013)

Symptoms of Prader-Willi associated with interference in circadian, metabolic genes.

Magel2, a Prader-Willi syndrome candidate gene, modulates the activities of circadian rhythm proteins in cultured cells (Devos et al., 2011)

Circadian fluctuation of plasma melatonin in Prader-Willi’s syndrome and obesity (Willig et al., 1986)

And the connection with LIGHT:

Artificial light at night: melatonin as a mediator between the environment and the epigenome (Haim and Zubidat, 2015)

Circadian behavior is light re-programmed by plastic DNA methylation (Azzi et al., 2014)

PWS is much worse than just nutrient partitioning (seriously, just spend a few minutes on any Prader-Willi support forum or this; maybe it is an appetite disorder, but given the data on weight gain [mostly fat mass] and weight loss [mostly muscle mass], it seems far more likely a circadian disorder of nutrient partitioning),
but that component jumped out at me; more specifically, despite the only positive results coming from non-dietary interventions, researchers were still all “#CICO.”

“Lean meat, sugar-free Jello, and skim milk”
FFS

Circadian biology, hormone replacement [where appropriate], and figure out if any specific diets help.  PMSF/CR doesn’t work unless “refrigerators and cabinet pantries are locked shut.”

Maybe this applies to other forms of obesity, too.
Maybe.

For personalized health consulting services: drlagakos@gmail.com.

Check out my Patreon campaign! Join the community of over 300 members for up-to-date information about a variety of topics in the health & optimizing wellness space. At 5 bucks a month, can’t beat it!

Affiliate linksKetoLogic for keto-friendly shakes, creamers, snacks, etc. And get 15% off your ketone measuring supplies HERE.

Still looking for a pair of hot blue blockers? TrueDark is offering 10% off HERE and Spectra479 is offering 15% off HERE. If you have no idea what I’m talking about, read this then this.

Join Binance and get some cryptoassets or download Honeyminer and get some Bitcoins for free

20% off some delish stocks and broths from Kettle and Fire HERE

If you want the benefits of  ‘shrooms but don’t like eating them, Real Mushrooms makes great extracts. 10% off with coupon code LAGAKOS. I recommend Lion’s Mane for the brain and Reishi for everything else

Join Earn.com with this link.

Start your OWN Patreon campaign!

calories proper

“Insulin Dynamics”

This one has a bit for everyone.

 

Relationship of Insulin Dynamics to Body Composition and Resting Energy Expenditure Following Weight Loss (Hron et al., 2015)

 

I think study was actually done a few years ago, originally published here (blogged about here), and re-analyzed through the eyes of Chris Gardner.  I think. (But it doesn’t really matter as the study design appears to be identical.)

 

Experiment: give someone an oral glucose tolerance test (75 grams glucose) and measure insulin 30 minutes later.  Some people secrete more insulin than others (a marker of insulin resistance); these people also have a lower metabolic rate after weight loss = increased propensity for weight regain.  However, if these people follow a low carbohydrate diet, then the reduction in metabolic rate is attenuated.  Some people who don’t secrete a lot of insulin after a glucose load may do better in the long-run with a lower fat diet.

 

Continue reading

Some nuances of Intermittent Fasting

Intermittent fasting (IF) is not a universal panacea, regardless of whether you’re not eating anything at all for a few days each week/month or just restricting your feeding window to a few hours per day.

Some protocols, eg, 20h fasting every second day, significantly improve insulin sensitivity in adipose tissue (Halberg et al., 2005). This is expected to make fat gain easier, and while this wasn’t meant to be a study on body composition per se…

 

body composition

 

After just a few weeks, things weren’t changing in a good way (NS).

 

Continue reading

Ketosis is a hack: here’s why

There are multiple distinct flavors of diabetes/obesity, as evidenced by the fact that some people have: 1) impaired glucose tolerance (but normal fasting glucose); 2) others have impaired fasting glucose (but normal glucose tolerance); and 3) others have both.  This means there isn’t a linear relationship between these phenomena*.  There are also: 4) obese patients with normal glucose metabolism; and 5) lean patients with type 2 diabetes.

*I think the great Dr. Kraft may have missed some of the nuances here.

There is not 100% overlap among these, suggesting [confirming] distinct diabetes/obesity phenotypes (and probably causes & best treatments).

 

 

midnightsun

 

Continue reading

Dawn PheNOMNOMNOM

Many pre-diabetic, diabetic, and insulin resistant people have used the low carbohydrate diet to successfully manage their blood glucose levels.  It just plain works.  FACT (P<0.05).

However, a small subset of this population fails to achieve normal fasting glucose.  This is likely due, in part, to a type of circadian mismatch induced by aberrant meal timing and excess exposure to artificial light at night.  For an extensive list of citations supporting the former, see “Afternoon Diabetes;” stay tuned for evidence of the latter.  In brief, a combination of delaying food intake for as long as possible after waking in the morning (“skipping breakfast”) and consuming most calories at night = no bueno.  These behaviors can also promote a circadian mismatch and phase delay.  Hint: eat when the sun is up; sleep when it is down.

 

Continue reading

Artificial light regulates fat mass: no bueno.

“despite not eating more or moving less”

We’ve seen this time and time again: LIGHT IS A DRUG.

 

above quote is extrapolated from this rodent study: “Prolonged daily light exposure increases body fat mass through attenuation of brown adipose tissue activity.”

 

Artificial light impacts nearly every biological system, and it doesn’t even take very much to have an appreciable effect (think: checking your smart phone or watching a television show on your iPad in bed at night).  In this study, adding 4 hours to the usual 12 hours of light slammed the autonomic nervous system, disrupting sympathetic input into brown adipose leading to a significant increase in body fat  “despite not eating more or moving less.”

 

Continue reading

LIGHT, Leptin, and Environmental Mismatch

For a long time, the melanocortin system was basically thought to control the color of skin and hair.  It still does, and many redheads are redheaded due to polymorphisms in one of the melanocortin receptors.

Fast forward to 2015: to make a long story short, melanocortins are HUGE players in circadian biology.

 

POMC ACTH a-MSH

 

Brief background (also see figure above):

Fed state -> high leptin -> a-MSH -> MC4R (the receptor for a-MSH) = satiety, energy production, fertility, etc.

Fasted state -> low leptin -> AgRP blocks MC4R = hunger, energy conservation, etc.

MC4R polymorphisms in humans are associated with obesity.  Melanotan II causes skin darkening (marketed as “photoprotection” [no bueno, imo]), enhanced libido, and appetite suppression.

 

Continue reading

Circadian Disruption Impairs Survival in the Wild

…just read that huge disasters, ranging from Exxon Valdez to Chernobyl, may have been due, in part, to ignorance of basic principles of circadian rhythms.  Gravitas.

 

circadian rhythms

Continue reading

Meal timing and peripheral circadian clocks

More on why breakfast in the morning, with light onset is important to avoid circadian desynchrony.

FOOD is excellent at entraining peripheral circadian clocks: if you restrict animals to one meal per day, their peripheral circadian clocks rapidly become entrained to this, regardless of when the meal is administered (Hirao et al., 2010):

 

zeitgeber entraining

ZT0 = “zeitgeber time 0,” or “lights on.” pZT indicates a phase shift coinciding almost exactly with meal timing. Mice normally eat at night, but this doesn’t stop their peripheral clocks from entraining to the day time if that’s when their fed.

This study took it to the next level: they fed 2 meals per day, varying in size, time of day, and duration between meals in almost every conceivable combination.  Actually, it was a quite epic study… some poor grad students working, literally, around the clock, for months…

Continue reading

Entraining Central and Peripheral Circadian Rhythms

“Desynchronization between the central and peripheral clocks by, for instance, altered timing of food intake, can lead to uncoupling of peripheral clocks from the central pacemaker and is, in humans, related to the development of metabolic disorders, including obesity and type 2 diabetes.”

If you haven’t been following along, a few papers came out recently which dissect this aspect of circadian rhythms — setting the central vs. peripheral clocks.

In brief (1):  Central rhythms are set, in part, by a “light-entrainable oscillator (LEO),” located in the brain.  In this case, the zeitgeber is LIGHT.

Peripheral rhythms are controlled both by the brain, and the “food-entrainable oscillator (FEO),” which is reflected in just about every tissue in the body – and is differentially regulated in most tissues. In this case, the zeitgeber is FOOD.

In brief (2):  Bright light in the morning starts the LEO, and one readout is “dim-light melatonin onset (DLMO),” or melatonin secretion in the evening. Note the importance of timing (bright light *in the morning*) – if bright light occurs later in the day, DLMO is blunted: no bueno.

Morning bright light and breakfast (FEO) kickstart peripheral circadian rhythms, and one readout is diurnal regulation of known circadian genes in the periphery.  This happens differently (almost predictably) in different tissues: liver, a tissue which is highly involved in the processing of food, is rapidly entrained by food intake, whereas lung is slower.

Starting the central pacemarker with bright light in the morning but skimping on the peripheral pacemaker by skipping breakfast represents a circadian mismatch: Afternoon Diabetes? Central and peripheral circadian rhythms work together.  Bright light and breakfast in the morning.

Continue reading