Maintaining muscle function in to old age

An aside: Public Service announcement. I seem to have a lot of Faceache/book friend requests coming through at the moment. Once upon a time I accepted all friend request and have read some interesting posts as a result. But I don't use Faceache for anything technical. The occasional orchid picture or flat water paddling snap is about it. So now I don't accept friend requests unless I know the person. There's nothing Hyperlipid-ish in my FB posts and the algorisms bury the social stuff I'd like to see if I have too many friends. Sorry if it seems rude, it's not meant to be but there is no way round it. End of Public Service announcement.

Back to the post:

The start of the current gross stupidity of lockdown-2 seems to have vanished in to the haze of the past. I can't remember when I last went bouldering, pre-idiocity. I guess it was some time last December. In the dim and distant past of lockdown-1 the climbing wall was completely reset but during the current period of enforced sarcopaenia only small areas were changed, so I got the chance to see how well I fared on some familiar routes after months of enforced idleness.

Pretty well. Endurance was a bit down and finger strength was laughable but on routes with big chunky handholds going up the main competition wall my bulk muscle seems to cope remarkably well.

On which subject I was interested in this paper put up on Faceache by Jay Wortman

The ketogenic diet preserves skeletal muscle with aging in mice

which is strong in it bias-confirming ability, bearing in mind that the keto mice were not exactly spending hours a day in the gym. It's the same group that produced this study

A ketogenic diet extends longevity and healthspan in adult mice

which is also exactly what you want to hear if you are an old bloke like me with young kids.

But I never blogged about the original paper. It has a certain flaw, common to both papers, which made me slightly cautious. The paper is best described as one of those "think about it" studies. Here are the diets used for both:

and here are the survival curves

The first problem is that there is no mention of gas chromatography. We have no idea of what the PUFA content of the lard was and the lard makes up something over 80% of the calories of the ketogenic diet.

In a deeply ketogenic diet such as F3666 it doesn't matter what the PUFA content is and the lard content is relatively low anyway. But for a rodent diet supplying 10%of calories as protein and maybe 20-25% of calories as PUFA it might matter. It mattered in these papers:

"During this one month [ie the lead-in at 12 months of age] period, food intake was measured to determine the daily food intake required by these animals. At 12 months of age, mice were randomly placed on one of three diets: control, low-carbohydrate diet (LCD), or ketogenic diet (KD). The control diet contained (% of total kcal) 18% protein, 65% carbohydrate, and 17% fat. The LCD contained 20% protein, 10% carbohydrate, and 70% fat. The KD contained 10% protein, <1% carbohydrate, and 89% fat. For the longevity study, food intake was set at 11.9 kcal/day, and decreased to 11.2 kcal/day after weight gain was observed during the first weeks of the study."

The studies combined a ketogenic diet with calorie restriction. Calorie restriction is a known longevity promoter. Duh. And keto didn't maintain a normal weight.

Lard can contain anything from almost no PUFA up to more than 30% PUFA, depending on what the pig was fed on and how adulterated the lard has been with cheap vegetable oils.

So these ketogenic mice had to be on a calorie restricted diet because otherwise they gained weight. They were on a diet containing around 20%-ish of calories from linoleic acid. If they felt a hypo in the middle of the light period they would have eaten to correct the hypo. Pathological insulin sensitivity. Or just the loss calories in to adipocytes without a hypo would generate simple hunger to off set those calories lost in to fat calls, ie weight gain.

Of course it's just a rodent study and maybe people would be different.

Or, more likely, maybe not.

As a more general point it's also worth noting that the improvement is in the median lifespan, not peak longevity. The first mouse to die was in the keto group, the last in the low carb group. Median does not mean an intervention is invariably perfect for all individuals.

But it's as good as we have at the moment.

Peter

The ginger paradox (6) Reward

Edit: The capitalisation of Reward is sarcasm. End edit.

Corn oil is very Rewarding™ for rodents. These people are working hard at the mechanism:

Sham feeding corn oil increases accumbens dopamine in the rat

so let's not assume that Reward is some airy fairy concept, it's fully physiological. How Rewarding corn oil is in rodents is beautifully illustrated by the paper I  discussed recently in which mice, when given the choice, voluntarily consumed pure corn oil until it comprised roughly 84% of the total calories in their diet. Of pure fat.  Without training of any sort. This is the paper:

Voluntary corn oil ingestion increases energy expenditure and interscapular UCP1 expression through the sympathetic nerve in C57BL/6 mice

So of course the mice became obese. Okay, I'm making that bit up. Massive consumption of Rewarding corn oil does not make mice obese. They eat a little extra, admittedly, but that is because the metabolic effect of an 84% corn oil diet is to instigate uncoupling. A quirk of the biochemistry of linoleic acid, uncoupling proteins and rodent brown adipose tissue means that a certain amount of energy is wasted as heat, so the mice have to consume a little more corn oil to make up for this loss. A few extra total calories were consumed without any extra weight gain.

Metabolism + extra heat production = an extra amount of food has to be is eaten to maintain normal weight.

Simple.

Going on to look at mechanisms of Reward, this study 

Increased Levels of Extracellular Dopamine in the Nucleus Accumbens and Amygdala of Rats by Ingesting a Low Concentration of a Long-Chain Fatty Acid

found that the Reward of corn oil is neuronal, it comes from local metabolism of the oil on the tongue using a lingual lipase so that a tiny concentration of FFAs is sensed by receptors in the mouth and nerve signalling from here drives the dopamine release in the brain. You can bypass the lipase on the tongue by adding as little as 1% unesterified linoleic acid to mineral oil which mimics the approximate amount of FFAs provided as a stimulus from the more normal corn oil/lipase process.

To make it absolutely clear:

Mineral oil carrying 1% of free linoliec acid is as Rewarding as 100% neat corn oil because both provide roughly the same FFA drive to the sensory cells. You can measure the dopamine release in the rodent brain. It's the same because the sensory cells on the tongue see the same concentration of FFAs.

I have a thought experiment.

What if one group of mice/rats were given chow plus access to neat corn oil and another group of mice were given chow plus access to mineral oil with 1% free linoleic acid added?

The oils are equally Rewarding.

Would the mice consume the oils in equal amounts because both are equally Rewarding?

If the oils were consumed in equal amounts would the mineral oil mice lose weight?

Or would they eat extra chow?

My bet is that if you ran such a study for eight weeks the mice with access to the mineral oil wouldn't touch it with a barge pole. It might release dopamine in the nucleus accumbens but it's not going to do much to fuel metabolism. That would need chow. Maybe there might be some recreational flavoured mineral oil consumption but I think that would pale quite rapidly.

Oooooooh! They might develop Reward Resistance! Like leptin resistance but dumber.

Reward is the refuge of researchers who consider obesity is caused by eating in excess of your metabolic needs.

A more sensible view of obesity is that it results from a metabolically mediated loss of calories in to adipocytes which then requires more calories to be eaten to meet normal metabolic needs. In the same way as orlistat requires over eating to compensate for fat loss via faeces, so "fake" corn oil (1% linoleic acid in mineral oil) would require extra chow to make up for the lack of calories in that highly Rewarding fake oil. And why feeding D12492 means rodents have to consume extra D12492 because they lose calories in their adipocytes.


Just to summarise: high Reward food makes you fat only if its metabolism result in energy sequestration in to adipocytes. 

Real corn oil at 84% of calories is not obesogenic because it does't sequester calories in to fat cells. I don't care how Rewarding it is. Nor does metabolism care.

Peter

Surwit diet and derivatives (4)

I've been interested in the Surwit diet for years. It's a fascinating diet, high in saturated fat, low in PUFA yet undoubtedly obesogenic.

It's an interesting paradox to think about. As occasionally happens I found a non related paper which gives some suggestion of the mechanism. Here it is:

Characterizing the effects of saturated fatty acids on insulin signaling and ceramide and diacylglycerol accumulation in 3T3-L1 adipocytes and C2C12 myotubes

The paper uses adipocyte-like 3T3-L1 cells or muscle-like C2C12 myotubes. The 3T3-L1 cells might be worth another post in future, today is about the myotubes.

They looked at many things, but most interesting are the data on the ability of insulin to promote the storage of glucose in glycogen granules. I, being me, would look at this as a surrogate for un-measured lipid storage as lipid droplets in muscle cells. One of the cardinal rules of ectopic lipid deposition research is to never, ever suggest that myocyte lipid droplets might be enlarged by insulin signalling. They will be. Just like glycogen granules are enlarged by insulin.

So, practicalities. The myotubes were prepared in "low glucose" DMEM which is probably code for 5mmol/l, ie a normal physiological glucose concentration. To this medium was added a fatty acid at 0.75mmol/l, ie moderate fasting levels. Cells were incubated for 16 hours and then treated with supra-maximal insulin.

They noted that elevated pure palmitate is utterly harmless to cells in culture with normal glucose levels:

"Under these conditions, no signs of cell death were observed"

which certainly is not the case using 25mmol/l of glucose!

Here are the gels they obtained:

The top row, highlighted in red, is demonstrating the presence of phosphorylated (activated) Akt, a core insulin signalling step. We are comparing P-Akt under insulin and 5mmol/l glucose with that under insulin and 5mmol/l glucose plus 0.75mmol/l palmitate. It's clear that insulin signalling is markedly blunted by palmitate. If we look at the dashed oval we can see that the P-Akt band under oleate is comparable to that of the control.

The same applies to the level of phosphorylated glycogen synthase kinase 3 beta, a key enzyme in activating glycogen formation and outlined in blue. P-MAPK is irrelevant today but, again, might be interesting in the future.

Convincingly, palmitate causes insulin resistance and oleate doesn't. Bear in mind that this is a highly constrained experiment to make a specific point. These is no mention of ROS generation but it is worth looking at this from the Protons/ROS viewpoint.

Palmitate has an FADH2:NADH ratio of 0.484

Oleate has an F:N ratio of 0.457

In this experiment conditions are carefully controlled to give us an all or nothing response, almost like switch. The switch trips somewhere between an F:N of 0.484 and 0.457. Insulin resistant vs insulin sensitive. No double bonds vs one double bond.

It is possible to adjust the F:N ratio by smaller amounts than by adding a double bond simply by altering the length of a saturated fat. If we consider myristic acid the F:N ratio is 0.482 and for lauric acid it is 0.478.

The paper went on to look at insulin signalling using these fats and here are the gels they obtained:

At the extreme left is the control without insulin, next is control with supra-maximal insulin but no fatty acid, then rest of the bands have the indicated fatty acids added, all at 0.75mmol/l. I've put in the red line to divide insulin sensitive from insulin resistant results. Everything to the left of the line causes no insulin resistance, to the right significant insulin resistance. The switch is between myritic acid and palmitic acid, F:N 0.482 and 0.484.

I would expect C10 capric acid to be insulin signal facilitating and probably C8 caprylic acid too, although its strongly ketogenic effect and partial conversion to palmitate might make that less predictable.

Coconut oil is primarily medium chain triglycerides with F:N ratios on the insulin sensitising side of the switch. Formulating a high fat diet out of insulin sensitising fats combined with an insulogenic carbohydrate load seems like a good recipe for obesity.

It's always worth reiterating that there is no "switch" as such, there is a general integration of information about energy status and demand using ROS which can be pushed towards lipid storage or use depending on particular inputs. The F:N ratio looks like a switch in a very simple model asking a very simple yes-no question. But that's still useful information for understanding the Surwit diet.

Peter

The complete and unifying explanation of human evolution

Miki Ben-dor has a new post on his blog

The complete and unifying explanation of human evolution

If you've not read his blog before, now would be a good time to start.

Peter

The ginger paradox (5) and some speculation

TLDR: If resisting insulin is rendered impossible due to very, very high PUFA diets then mitochondria resort to uncoupling.

This paper 

Synergy of fatty acid and reactive alkenal activation of proton conductance through uncoupling protein 1 in mitochondria

reiterated the well known essentiality of FFAs for the activation of UCP-1 and added in the significant role of reactive alkenyl species. In more common parlance that would be lipid peroxides, primarily those derived from linoleic acid. I thought about it in this post.

This is the next step, which I specifically went looking for because this is how I think life should be organised. It is a perfect example of me having a huge bias, knowing what I want, and going looking for it. You have been warned.

Superoxide activates mitochondrial uncoupling proteins

It is utterly clear that UCPs in general suppress ROS generation and that some members of the family are not being used for thermogenesis at all, more likely for prevention of the generation of supra-physiological levels of ROS.

We have an interesting situation where PUFAs, the prime pathology of which is their failure to generate adequate ROS, are also extremely effective at facilitating uncoupling, which needs significant ROS generation to happen. Where does this superoxide come from?

This is the core question.  

Warning: I think step f) is the one I have least evidence for. Life is like that sometimes.

Okay. The story so far:

Caloric ingress in to a cell is controlled to an appropriate level while calories are freely available by limiting insulin signalling.

Insulin signalling is curtailed by driving electrons in reverse through complex I to generate superoxide and hydrogen peroxide which disable/limit said insulin signalling.

This reverse electron transport rises in direct proportion of FADH2 supplied compared to the amount of NADH.

The presence of double bonds in fatty acids limits FADH2 generation, limited FADH2 generation limits the control of insulin facilitated caloric ingress and continued insulin signalling diverts calories in to storage.

I have to accept that not all excess calories will be stored, some will continue to enter the electron transport chain as both NADH and FADH2. If electrons enter the electron transport chain when there is a low (relative) demand for ATP then

a) mitochondria membrane potential will rise, a direct consequence of the inability to limit electrons entering the ETC through complex I and multiple FADH2 entrance points. Protons are pumped but not used

b) the cytochrome C pool will become progressively more reduced, limiting it's ability to accept electrons from complex III

c) electrons will be transported through the cytochrome b centre of complex III back on to the CoQ couple

d) these electrons will replace those absent as a result of double bond containing fatty acid oxidation and will restore superoxide production

e) superoxide production, under these circumstances, is being facilitated only at the cost of high membrane potential secondary to low ATP synthase activity in parallel to excess calorie storage

f) if the double bond content of the lipids providing input to the CoQ couple from beta oxidation is very, very high then the need for negative feedback through complex III will be very, very high as well and will be associated with an excessively high membrane potential

g) the answer to excess membrane potential is uncoupling

h) superoxide positively regulates the activity of UCP-1 as do superoxide derivatives of LA

i) uncoupling allows the flow of electrons down the electron transport chain and lowers membrane potential, it immediately stops reverse electron transport/superoxide generation and converts the excess calories entering the cell in to heat, water and carbon dioxide

Summary:

Normally regulated calorie ingress to a cell occurs when linoleic acid is low.

Excess ingress from LA is dealt with by diversion to storage, leading to obesity.

Marked excess is dealt with by uncoupling which does not "require" obesity.

There are no hard boundaries between the above conditions, there simply appears to be an inverse "U" shaped curve in response to the content of linoleic acid in the diet. Such curves are common in nature.

A few last thoughts:

Simply looking at the experimental data the situation appears to be that including linoleic acid at levels between somewhere just under 10% up to somewhere in the high 20%s will facilitate excess insulin action and excess lipid storage. As we increase the supply of linoleic acid through the 30%s and in to the 40% region of calories then uncoupling becomes the primary molecular solution to a progressively more intractable problem.

It is worth pointing out that in a given mitochondrion there are lots of CoQ/CoQH2 molecules, lots of beta oxidation sites and, while the calculation of FADH2:NADH is useful for insight as to how RET works for a single fatty acid molecule, the mitochondria are integrating lots of FADH2 production sources, lots of NADH sources and are continuously monitoring the membrane potential (which is an integration of energy input/need) as well as the redox state of the CoQ couple.

What happens on a whole organism basis is also an integration of all of these effects. The mechanism for weight loss in high PUFA diets is both comprehensible and plausible.

The studies are real, the data are real.

Personally I still wouldn't go there, but understanding them is key. 

Peter

The ginger paradox (4)

Here we go with ad-lib corn oil.

Voluntary corn oil ingestion increases energy expenditure and interscapular UCP1 expression through the sympathetic nerve in C57BL/6 mice

Mice were either offered chow from a hopper or chow from a hopper with the option of corn oil from a drinker bottle in addition. They like corn oil.

The mice with access to corn oil ate more calories than those without:

but most calories weren't from chow, top line is grams of chow only, bottom line the weight of chow eaten when there is access to ad lib corn oil:

We can look at the total amount of corn oil consumed:

Assuming 9kcal/g we can now reverse engineer that to 16kcal of corn oil a day as part of a total daily intake of 19kcal. So that's 84% of calories from corn oil. As 55% of this 84% is linoleic acid that gives 46% of calories as LA. Well in to the weight loss range of intake noted for high LA safflower oil, in fact that's verging on a self selected ketogenic diet, which complicates matters a little.  With 16% of calories from chow this will also be rather low in protein, though far from zero carb. Just look at the RER if they have access to corn oil, the black circles. Yes, these mice really are oxidising lipid and very little else, but also bear in mind that exactly the same effect could be obtained with safflower oil under far from ketogenic/low protein conditions. Here are the RERs:

Anyhoo. What was the end result? These are the body weights at the end of the eight week trial:

More calories, more oxygen consumption, same body weight.

This looks like a generic property of linoleic acid in exactly the same way as weight gain is at lower levels. The Jacobs study rats were around 24%, on the border between obesogenic and weight limiting effects, on the obesity side.

To get weight loss you need to go higher with the LA.

Just before I finish and post some speculation about mechanisms it's clear from the rest of this study that uncoupling is the answer to the paradox. In modern mice this is mediated through UCP-1 within the interscapular brown adipose tissue, as the paper went to considerable lengths to demonstrate.

This is the current level of development in the modern evolutionary terms of rodents. It's a sophisticaled high level system which will overlay the insulin system which will overlay the ROS system. It is perfectly possible to make a case for why this high level system is advantageous by thinking about the underlying ROS system.

I'll have a discuss about that in the next post.

This series is looking at body weight. Using an approach to normalise body weight which involves the incorporation of markedly unsaturated lipids in to the inner mitochondrial membrane does not strike me as a sensible thing to do. Might be a technique for looking good in your coffin.

Peter

The ginger paradox (3)

Here is the next step. Mice this time.

Prevention of diet-induced obesity by safflower oil: insights at the levels of PPARa, Orexin, and Ghrelin gene expression of adipocytes in mice

The basic study design was that mice were fed a control diet, a safflower oil based diet or a lard based diet for an initial 10 weeks. At 10 weeks half of the lard fed mice were switched to the safflower oil based diet and feeding continued for another 10 weeks.

Here are the diets

They measured the linoleic acid content by gas chromatography. That is very, very good. We can rough out the LA content of the control diet at around 5% of calories as LA, the lard diet at 11% of calories as LA and the high safflower oil diet at around 38% LA.

Here's what happened to the weights

As expected the lard mice became overweight by 10 weeks. Putting them on to 38% of calories as LA returned their weight to that of control mice or that of mice fed 38% LA safflower throughout the full 20 weeks.

This is not an isolated study showing the benefits of safflower oil, but it's one of the better ones. I find it impressive. It has to be understood.

Towards the end of the discussion in this paper the authors cite another gem which completely contradicts their own findings while providing more insight:

"These results are different to the study that the rats fed on 30% safflower oil and mice fed with 20% safflower oil showed significantly higher body weight, white adipose tissue weight, serum leptin, and hepatic PPARa mRNA expression [28]."

The paper they cite is this one:

Changes in liver PPARa mRNA expression in response to two levels of high-safflower-oil diets correlate with changes in adiposity and serum leptin in rats and mice

Here are the diets

Wow! Have you spotted it? Thats right. More excellent gas chromatography and suddenly you find out that "safflower oil" and "safflower oil" can be very, very different oils. This batch of safflower oil was 24.1% LA. In the highest fat diet we are looking at 24.1% of the 53.68% of fat calories as LA. That's 13% of calories as LA, bang in the middle of the obesogenic range. That's very different from the 38% which corrects obesity...

It must be sad trying to understand your own results and those of rival labs without the Protons/ROS hypothesis to fall back on. Must be awful.

Currently I don't think there is anything special about safflower oil. I think it is an effect the linoleic acid at very high dose rates. You should, theoretically, be able to do the same with corn oil. Sadly most of the corn oil based high fat diets aim to get in to the sweet spot of 10-20% of calories as LA. They want obesity after all.

If we are trying to generate diets with 40% or more of total calories from linoleic acid it will be much easier with safflower oil at 75% LA than using corn oil at 55% LA.

Interestingly mice appear to rather like corn oil. Let's look at a free choice feeding study next. Chow as pellets or corn oil from a liquid feeder bottle. Let the mice decide how much of each... And see if they get fat.

Peter

The ginger paradox (2)

Here is ref 17 from the previous post

Effect of short-term dietary fat on cell growth in rat gastrointestinal mucosa and pancreas

Here are the diets by weight of ingredients

and here are the relevant weights after four weeks on the diets

I think it's unarguable that the weight gains are only trivially different between the three groups. It becomes clearer when you look at lard in terms of linoleic acid level as opposed to accepting that it is "saturated fat". Modern lard is around 12% linoleic acid. It might have been a little higher or lower in the 1980s depending on how much adulteration with cheap seed oils the manufacture could get away with in those days or what the pigs were fed on 40 years ago. Lets go with 12% to include the splash of corn oil thrown in.

The control diet is reported as 16.8% total calories as fat and both high fat diets as 52% of calories from fat.

That makes the control diet around 9% linoleic acid, the lard diet 12% linoleic acid and the corn oil diet around 28%.

At 9% LA the control diet is already obesogenic. The lard diet is a bit worse but not in a different ball park, much as I would expect. The fascinating one is the lack of excess weight in the corn oil group, the group with the diet used by the Cairo study as their obesogenic one.

The easy part is to assume that all of the diets in the Jacobs paper are obesogeic, as is the corn oil diet used in the Cairo study. All of these rats gained about 150-180g. The control diet in Cairo was unspecified chow. If it contained 4% or less of linoleic acid we have a plausible explanation for the low weight gain in that control group. We just have to explain why the rats in Jacobs' paper on 12% LA weighed about the same as those on 28% LA.

This is very important to me. There are a series of papers using very high LA diets, especially Safflower oil based, which show minimal obesogenic effects and even the ability to partially reverse lard derived obesity. Something I have been thinking about for years.

Peter

The ginger paradox

For odd reasons I was looking for papers on orlistat, in particular for rodent papers about the drug which might demonstrate effects relevant to the Protons/ROS hypothesis.

Rodent reports seem to divide up in to those which use an intermittent oral dosing regime vs those which incorporate the drug in to food as a fixed component of the ration. It became clear that if you mix orlistat with the ration you can exactly titrate the amount of lipase inhibitor to the dose of fat administered and include this with every meal and every snack, whatever the size and whenever consumed. This latter has no bearing on the real life use of the drug where it is given three times daily to establish a background inhibition of enteric lipases and people have to judge their fat intake in relation to how far they are from the nearest toilet and if they are carrying spare underwear. Not the most successful or pleasant drug for weight loss per unit grief and it doesn't seem to work very well.

Of course unpredictable bowel function doesn't matter to a lab rat, it's not wearing underwear and it can pooh whenever it likes, wherever it likes because it lives in a mesh floored cage.

There is remarkably little in the rodent literature on orlistat alone for obesity control and mostly you have to look at drug or supplement trials where orlistat was used as the control/usual care group. In these trials it is usual to use intermittent oral dosing rather than admixture to the food because intermittent oral dosing doesn't work very well. If you have an ineffective but conventionally accepted drug that then provides an ideal comparator to show your intervention does something good.

Aside: Just think of metaclopramide. It was/is a standard antinausea/antiemetic for post op use. It is ineffective, dreadful stuff but it's licensed. Which makes it ideal as a "standard therapy" against which to compare a lovely modern drug such as maropitant or ondansetron. You know the latter are going to beat metaclopramide  hands down because metaclopramide is little better than placebo and makes you feel crap. Study design is important and this shows in the methods section. End aside.

However some trials do use the effective food admixture method. I found an innocent little study from 2013 which did just this:

Comparative evaluation of the efficacy of ginger and orlistat on obesity management, pancreatic lipase and liver peroxisomal catalase enzyme in male albino rats

It feels like a throwback to the 1950s. They generated their intervention (ground ginger, 5% by weight of the diet) by going to the local market in Cairo and buying some ginger, peeling it, washing it, mincing it and air drying it before milling it in to a fine flour to incorporate in to the diet. The comparator intervention was orlistat which they bought as capsules to be opened and incorporated in to the ration in a similar manner to the ginger.

The bottom line is that their ginger worked rather well compared to an unmodified high fat diet but sadly (for the ginger) the orlistat was incredibly effective, far more so than the ginger. This is why I got interested in the study. Not only did the rats on orlistat fail to grow, they had a marked increase in food intake. They ate a ton of high fat food yet put on remarkably little weight. There is no information provided about bowel function but I guess the rats on orlistat didn't wear underwear and they lived their lives metaphorically sitting on the loo. Certainly whenever they ate anything. Which was as often as possible.

The basic premise to orlistat is that if you take a drug which blocks fat absorption you decrease the functional "calories-in" so lose weight. Which is, of course, bollocks. What would actually happen is that you would eat more. You cannot fool your metabolism. You either eat more to meet your needs or you slow your metabolism to match your available calories. You feel cold, move as little as possible and dream about food. Most people would eat more.

This is what happened

Chow rats gained 60g, high fat fed rats gained 130g, orlistat treated high fat fed rats gained 7g. Seven grams. These rats did not want to be slim. They are not heading for the beach in a bikini. That low weight gain is malabsorption in action.

It causes hyperphagia because that is the only way the rats can even try to meet their caloric needs.

The implication of this study is that malabsorption makes you thin. That could be CICO. But orlistat malabsorption might also block linoleic acid absorption. That this might actually be true in real live people to facilitate a little genuine fat loss is where I was heading, but I lost interest when I tracked back through ref 17 to find that the high fat diet cited in this study is not obesogenic! Ref 17 as mentioned in:

"Group (2) G2: (High fat diet), rats of this group fed high fat diet (The diet contain 30% corn oil) according to Jacobs17"

A diet composed of 30% corn oil by weight, around 26% of calories from linoleic acid, is not obesogenic, in rats under the supervision of Jacobs.

Yet it clearly is obesogenic in Cairo.

Now that is interesting. These are thing which fascinate me. Ref 17 is next.

Peter

Butter vs peanut butter

I like this study, it's the one I always call "The Spanish Study" in my head:

Distinctive postprandial modulation of β cell function and insulin sensitivity by dietary fats: monounsaturated compared with saturated fatty acids

It was specifically designed to show that fat raised insulin and that saturated fat was particularly bad in this role.

It produced this graph:

Let's imagine the group leader has sketched out in advance the above graph or something like it which he wants the PhD student to aim for as their results.

Group Leader: How are you going to generate these graphs?

PhD student: Well, seems like a pot of yogurt, a slice of bread, some plain pasta and a dose of each type of fat might work...

Sadly life is not quite that simple. The insulinogenic components would need to be chosen to produce a small but measurable insulin response. Not so small as to be undetectable but not so large as to tax the pancreas or overwhelm the effect sought. Then there had to be enough fat to augment insulin secretion and generate the appropriate resistance to that signal, within the normal physiological range of pancreatic function. So the amount of fat would have to be very carefully adjusted to give an ideal amplification of the carbohydrate/protein insulin signal. In the end it turned out to be necessary to adjust the quantities of food directly to the body surface area of the participants, not a fixed meal and not even calories merely adjusted to bodyweight. The use of body surface area is normal for calculating doses for various highly toxic treatments such as chemotherapy because dosing has to be as precise as possible in this instance. Turns out this dose/surface area was needed to correctly dose the fat (50g/m2) and pasta (30g/m2) to illustrate the double bond/ROS effect. The yogurt and plain bread got a free pass.

But they did all of this successfully, got the "down" on saturated fat and polished the halo of olive oil. 

I'm both impressed and grateful.

Now let's go back in time to the 1980s and look at this study:

Concurrent ingestion of fat and reduction in starch content impairs carbohydrate tolerance to subsequent meals

The agenda in this study is to show that fat blunts insulin response to carbohydrate ingestion but causes delayed insulin resistance during the following meal. They threw in a butter group and a peanut butter group. Here are their results, I've chopped off the right hand end about the follow on meal as it's not relevant here:

We can also ignore the 2 X WB line which was just 480kcal of bread with a smear of cottage cheese. The lower two lines are bread alone  vs the same dose of bread with some fat. Both fat sources produced results which were indistinguishable so were combined. The insulin response is exactly the same with or without fat, saturated or unsaturated.. 

How do you reconcile the two studies?

This second one used a fixed calorie meal with 50g of carbohydrate and 25g of protein. Fat provided around 25g for each meal.

The dose of insulinogenic substrate was well over half of the calories in the meal, the fat well under half. The total gross insulin response was to the bread, not the fat. The amount of fat was insufficient to make any detectable difference to that insulin response.

Just compare the insulin values achieved in each study, the Spanish study use a fat-free insulinogenic stimulus raising insulin from 50pmol/l up to about 70pmol/l. The bread meal raised insulin from around 70pmol/l (10mU/l) to around 400pmol/l (60mU/l), even without any added fat! There is no scope for picking up any effect of the fat, let alone from the nature of the fat. The bread effect was approaching maximal, even though it didn't quite max out the pancreas as much as the double bread meal did.

Ultimately you design your study around the result you want to generate. Sometimes it's easier than others.

The Spanish study was remarkably cleverly done but looks like they had to work hard to get the results they wanted. I still like it, even though I markedly disagree with their interpretation of the findings.

Peter

Israel is doing really well for COVID-19 vaccination

Israel has missed out on submitting data to EUROMOMO for week 13 of this year. During week 12 they recorded a marked, unique, increase in all cause mortality in their over 65 year olds, almost all of whom are now fully vaccinated against COVID-19 with the Pfizer vaccine.

These people do not appear to have died of COVID. It seems to be mostly cardiac problems which don't seem to be particularly well defined. Translated from a Hebrew newspaper via Google as a specialist saying "We are now witnessing a murky wave of heart attacks."

The now-outdated week 12 data are presented on-line by a group called Swiss Policy Research. I have no idea of their affiliations, politics or agenda and, frankly, I don't care. The graph certainly looks like a EUROMOMO graph and Israel has not, as of today, submitted their week 13 data.

Of course these data are provisional and, of course, numbers of deaths in week 13 might be really low but the Israelis just haven't gotten around to submitting the numbers yet. Maybe they're too busy partying in celebration of their vaccine success. EDIT Or Passover! END EDIT

I'm uncomfortable about ADE with these vaccines. I'm concerned about triggering auto-immune diseases. I've not really considered the thrombogenic/disseminated intravascular coagulation potential but it's also there to worry about.

The European Medicines Agency is responsible for the authorisation of SARS-CoV-2 vaccines in Europe.

Doctors For COVID Ethics are currently in discussion with the head of the EMA with a view to starting a prosecution of EMA for crimes against humanity relating to these vaccines. The physiology and immunology which they cite as being relevant (and as yet un-assessed by the EMA) make a very interesting case.

I personally am very, very cautious about yielding to the coercive pressure to accept such a vaccine here. Coercion is becoming a part of reality in the UK. These vaccines are absolutely experimental in their technology, have never before been licensed anywhere in the world and will provide no benefit for the vast majority of the recipients. The sooner the legal cases actually begin the better. Sadly a victory in Europe would not get we folks in the UK out from under the Boris Johnson jackboot.

As always: If you are at risk of dying from COVID-19, take the vaccine. If you are not, think hard about it.

Peter

More musing about vaccines

We vets vaccinate dogs against infectious canine hepatitis. Many, many years ago we used a live vaccine derived from the adeno-1 virus, unless the animal was a sight hound, Salukis or Borzois being particular concerns. For these we had a less effective/convenient inactivated vaccine (not sure which adenovirus strain this came from) because sight hounds (no pun) were particularly prone to blindness with the live attenuated A-1 vaccine. As the manufacturers of the A-1 vaccine stated, from memory, it "may cause corneal oedema which is usually transient".

If you translate that in to real terms it comes out as "can cause blindness which can be permanent".

Woe betide you if your boss found you had inadvertently picked up the wrong vaccine vial for a sight hound. Obviously, not all sight hounds went blind after the A-1 live vaccine.

The whole problem disappeared with the advent of the A-2 live vaccine (which we love), free from the corneal side effect, so I doubt kiddie vets are even aware that blindness was a predictable problem following a routine vaccination if you (and your patient) were unlucky. The modern A-2 vaccine is so effective I doubt we ever see infectious canine hepatitis nowadays but I recall seeing transient corneal oedema in at least one clinical viral hepatitis case in my early days.

I am one of those selfish people who is intending to defer my SARS-CoV-2 vaccination. The Queen does not approve. 

Why should I be so selfish? Many reasons, but the main one is an uncomfortable feeling about how m-RNA vaccines work. As I understand it, you inject a section of m-RNA enclosed in a vesicle which is muscle absorbed. The m-RNA is used by normal ribosomes to generate viral spike protein which is presented to the immune system on the surface of the muscle cells affected. The immune system sees the protein and responds as to the virus. You become immune. The residual m-RNA is fairly rapidly degraded and disappears until you get your next dose. I stand to be corrected if I am misunderstanding this.

I have no idea whether muscles infected with the field virus express spike protein on their surface. I suppose they might. Or they might not.

Does anyone think that expressing a viral spike protein on muscle cells will only generate an immune response to only that spike protein? Or, in the immune melee which results from muscle expressing an highly immunogenic foreign protein, would an immune response to other components of muscle surface occur?

How might you recognise such a response?

Myalgia perhaps?

Would it be better or worse the second time you played this game?

What would happen if you had already recovered from the field virus and so were very primed to effectively attack anything looking remotely like a SARS-CoV-2 virus surface protein?

So many questions.

Myalgia is common after vaccination, worse after the second dose and worse still if given to someone who has previously recovered from the field virus infection.

Heart muscle is not skeletal muscle. It probably "looks" different to the immune system. But it's not completely different. I, personally and just for myself, am not comfortable with making antibodies which might precipitate an attack on my myocardium. Which might not occur. Or, if it did, might be temporary. Or not. I remember the live A-1 adenovirus vaccine. This is just one of the problems of being as old as I am but still remembering my clinical experiences from the early 1980s.

So. Does myocarditis occur in the aftermath of SARS-CoV-2 m-RNA vaccination? Of course not. Do you have any concept of how much money is involved in these vaccines?

This is just from twitter so can be ignored if you wish:

https://twitter.com/AlexBerenson/status/1369017958345891840

I have no ideal who the tweeter is and I don't read Hebrew, so I have no way of following this up.

But I note that the Queen's recently vaccinated hubby has been passed around from hospital to hospital and has gravitated to being managed by cardiologists for his mystery illness. He's very elderly so this is probably just random chance and nothing to do with any vaccine.

The first Swine Flu pandemic vaccination program was halted in 1976 due to worries about Guillain-Barré syndrome from the vaccine. The same happened in the second Swine Flu pandemic of 2009-10 when narcolepsy halted that vaccination program.

The m-RNA vaccine will obviously be problem free.

I'm so selfish.

Peter

BTW, each person should assess their own risk from the virus vs their concern re the vaccine. Personally I consider my risk from the virus is very low so am un-enthused at any risk from the vaccine. Certainly for the next couple of years. It remains to be seen how much coercive pressure is going to be applied nation-wide and especially to myself to get vaccinated. I've ignored six invitations so far.

A chat with David Gornoski

Okay. Head briefly above water for a few minutes!

I had a chat with David Gornoski last week (or rather it was the week before, things are a little hectic here). You can find it at

https://aneighborschoice.com/peter-dobromylskyj-interview-how-obesity-is-fueled-by-omega-6-seed-oils/

and on Youtube here

David had emailed me after a number of people he'd already interviewed had mentioned the Protons/ROS hypothesis and Hyperlipid, so mostly I was trying to to get across the where the key concepts came from. I guess I rabbited on a lot about about the four main papers which shaped the idea. Then we wandered away on to more general things.

I think the microphone works!

Peter

Just an announcement

The World Nutrition Summit is coming soon as a virtual meeting based in South Africa. The organisers kindly asked for a presentation based around the ROS hypothesis of obesity. I haven’t tried to make it particularly user friendly, Mike Eades has already done that, this is more of a brief whirlwind tour of the many technical papers which went to make up the Protons thread and spawned the idea.

Thee's a lot more information from the Nutrition Foundation here.

I bought a microphone.

Peter

Hall and CICO part 3

Okay, this is the image I missed on my first read through the results/methods of Hall's latest offering:

I have to apologise for failing to pick this up possibly because I would never read the discussion or conclusion of a Hall paper. My interest in what Hall thinks is distinctly limited. The image shows a delay in the onset of fat mass loss with LC which then proceeds at a remarkably similar rate to the fat loss in the LF group.

But clearly, the changes in fat mass under LC trend upwards (ns) initially before trending downwards, (also ns) compared to fat mass at initiation of the diet.

As David Ludwig has pointed out, appetite suppression on LC can be delayed and shows most reliably from 2 weeks onwards. This might well be related to the rising levels of ketone bodies providing enhanced energy availability as ketosis develops using the concept outlined here:

Effects of Dietary Carbohydrate Content on Circulating Metabolic Fuel Availability in the Postprandial State

This brings to mind a very short term study from some time ago looking at ketogenic diets based around saturated vs polyunsaturated fats.

Differential Metabolic Effects of Saturated Versus Polyunsaturated Fats in Ketogenic Diets

Both diets were individualised to be weight maintaining, so we can say nothing about spontaneous food intake (ie appetite, ie weight/fat mass changes). The main point of interest is the very right hand end of Figure 1:

which shows calculated insulin sensitivity. Under high PUFA intake insulin sensitivity, after an overnight fast, is clearly enhanced.

We have no information about the FFA levels so assessing the "blood energy content" is impossible for either diet. However we can look at the relative changes in glucose vs beta hydroxybutyrate (BHB). They look to be reciprocal, but this is simply an artefact of percentage change.

Glucose drops by 10% from normal fasting levels in the PUFA group, measured as 79.2mg/dl, a sizeable number. Ketones in the PUFA group rise by 10% over the same period. But this is 10% of 1.34mg/dl, a vanishingly small amount, physiologically. There is no ability for this modest rise in BHB to offset the fall in glucose. The energy content of ketone bodies and glucose are approximately equal, per gram. Free fatty acids would be the unknown confounder.

That study looked at high (10% energy) vs very high (42% energy) from PUFA intakes, both under modest ketogenic conditions.

Hall's study looked at a mildly ketogenic diet with around 15% of energy from linoleic acid, a pathologically high intake, in comparison to a carbohydrate based diet deriving around 3% of calories from linoleic acid, ie a physiological linoleic acid intake. 

Linoleic acid at 3% of calories, ie very low, will have no blunting effect on the ability to limit caloric ingress in to adipocytes ("loss") in the peak-absorptive period (so will not generate the need to eat more food to offset this loss in to adipocytes) and will not facilitate pathological insulin sensitivity to allow hypoglycaemia in the post-absorptive period (with subsequent hunger).

I think we can sum Hall's study up in the words of the abstract section:

"One participant withdrew due to hypoglycemia during the low-carbohydrate diet."

translated as

"One participant withdrew due to hypoglycemia during the high-polyunsaturated fatty acid diet."

The other participants had to (spontaneously) eat more to successfully avoid these problems during the first week. 

The effect diminished through the second week of the study as ketones rose further to compensate for the hypoglycaemic effect of excess PUFA.

Peter

Hall and CICO part 2

I have to say that I have enormous respect for Tucker Goodrich's self restraint in not commenting further on the single largest confounder in the latest Hall study:

Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake

which starts its abstract with:

"The carbohydrate–insulin model of obesity posits that high-carbohydrate diets lead to excess insulin secretion, thereby promoting fat accumulation and increasing energy intake."

If the simplest CIM model of obesity was correct then eating a diet which raised insulin, like this:

to a peak of 120microU/ml and kept it elevated for three hours, should result in marked sequestration of lipid in to adipocytes with subsequent weight gain.

It doesn't.

The question is how this occurs.

Over the years I have had a couple of attempts to understand "carbosis", which this low fat group appears to be demonstrating. None of my attempts have been particularly satisfying from the metabolic point of view. Let's try again.

In the immediate aftermath of the low fat test meal glycolysis is very active. This is facilitated by the elevated insulin translocating GLUT4s to the cell surface, which will facilitate the ingress of glucose.

Insulin will also facilitate the ingress of FFAs via CD36 translocation to the cell membrane but, at the same time, insulin will simultaneously lower FFAs:

With plasma FFAs at around 0.1mM it doesn't matter very much how many CD36 receptors are present on the cell surface, fatty acid oxidation will be a limited source of both NADH and FADH2 supply to the electron transport chain.

In addition to facilitating glucose ingress in to cells, insulin also drives the activation of the pyruvate dehydrogenase complex. This increases the translocation of pyruvate via its proton gradient coupled transporter in to mitochondria and ensures its metabolism to acetyl-CoA.

Glycolysis to pyruvate generates two molecules of cytoplasmic NADH for each molecule of glucose utilised. Much of this NADH will be reconverted to NAD+ by the malate-aspartate shuttle, passing the electrons to generate NADH within the mitochondria. If the rate of generation of NADH exceeds the capacity of the malate-aspartate shuttle, cytoplasmic NADH levels will rise and, secondary to this, the level of lactate will rise to resupply NAD+, using lactate dehydrogenase.

We can get an idea of how much the cytoplasmic NADH levels rise from the output of lactate in to the bloodstream of the study subjects after the low fat test meal. Like this:

I find a post prandial lactate of just under 3mM quite impressive. I would suggest that the NADH:NAD+ ratio is high.

So the next question is, what might an elevated cytoplasmic NADH level do to the glycerophosphate shuttle?

If we assume that high cytoplasmic NADH activates the glycerophosphate shuttle we will have the transfer of electrons from cytoplasmic NADH to the intra-enzymic FAD of the mitochondrial component of the glycerophosphate shuttle, mitochondrial glycerol-3-phosphate dehydrogenase.

From here the input is from the outer surface of the inner mitochondrial membrane directly on to the CoQ couple. From the mitochondrial point of view, that cytoplasmic NADH never arrives (it should have entered using the malate-aspartate shuttle). Instead it is "seen" as an FADH2 input, with all of the implications that has related to the FADH2:NADH ratio intrinsic to the Protons thread.

Under the influence of insulin there is clearly a great deal of cytoplasmic NADH generated from glycolysis and it is this action of insulin which must be limited to avoid excessive caloric ingress.

With glucose at 120mg/dl (sorry for the quaint units):

and insulin at 120microU/ml there are lots of calories entering cells. With FFAs at or below 0.1mM they will not be a significant source of either NADH or FADH2.

Fatty acids are out of the equation. So the signal for cellular satiety, driven by ROS, is going to come from the rising FADH2:NADH ratio generated by the glycerophosphate shuttle converting NADH to FADH2.

Ultimately the sensing of a cellular "satiety" level of substrate ingress will be signalled the generation of high-physiological levels of superoxide and hydrogen peroxide, facilitated by the glycerophosphate shuttle. I won't mention negative feedback from complex III but it will contribute too.

What will not be involved to any significant degree is beta oxidation. FFAs are low at the time of peak calorie availability/storage. And of those FFAs there will be very, very little linoleic acid.

A very low fat diet side steps the problems caused by linoleic acid failing to allow satiety-facilitating levels of ROS to be generated. Linoleic acid is simply out of the equation, what little there is of it from the diet being squirrelled away in adipocytes during the period of peak calorie availability. It is simply not there to interfere when cellular satiety is being successfully signalled.

Couple that with the fact that the low fat meal plans provided a linoleic acid supply limited to 3% of calories, it is quite easy to see how a group of 20 slightly chunky young Americans (BMI 27ish, 32% body fat, not the Arnie look for the slightly high BMI!) might be suffering from chronic linoleic acid toxicity. Dropping to 3% energy from linoleic acid is going to be markedly less fattening than the level which might be found in any version of the SAD.

Low fat is synonymous with low linoleic acid. High carbohydrate/high insulin has its own satiety mechanism, more dependent on the glycerophosphate shuttle, which is impervious to small amounts of linoleic acid. And with a diet of 2000kcal supplying LA at 3.1g/1000kcal, then just over 6g/day is not a lot to worry about.

I'll stop here to keep it simple. Obviously the tendency to normalise weight in the low carb period is directly related to low insulin, facilitating lipolysis. Once insulin is low enough, ie once carbohydrate intake is low enough, then linoleic acid, even at a total of around 40g/d (as was eaten during the LC phase), becomes unimportant.

EDIT, missed the lack of fat loss on LC! I guess 40g/d of linoleic acid with low but not basal insulin is too much! The is an update on this here. END EDIT.

Until you get just a little bit of carb creep of course... As carbohydrate and associated insulin rises then that approximately 13% of calories as LA is going to facilitate weight regain with a vengeance.

Peter

Hall and CICO again

I have no free time at the moment so no real chance for blogging. Apologies for the undoubtedly multiple typos and grammatical errors in this hastily written post.

Raphi and I had a chat which is up on Youtube here

Peter & Raphael talk about fatty acids, mitochondria, the origins of life, covid, vaccines & keto

and I also picked this thread up on twitter, again via Raphi

https://twitter.com/DaveKeto/status/1352389424714113024

which sums up why I don't do twitter. To join this discussion would take weeks of careful thought and reference trail following. However this review (DO NOT download it from SciHub!!!!!! Or if you do, make a donation. I didn't say that) came out of it:

Free Fatty Acids and Insulin Secretion in Humans

which has a core, absolutely correct statement:

"In fact, they [FFAs] increase insulin precisely to the degree needed to compensate for the fatty acid–induced insulin resistance."

After that it's all about ROS and double bonds, a concept which Boden (who sounds a really interesting chap) lacked at the time. The basic CIM (Carbohydrate Insulin Model) of obesity is undoubtedly incomplete and, nowadays, is a straw man for people like Hall to use to facilitate career enhancement. As in

Effect of a plant-based, low-fat diet versus ananimal-based, ketogenic diet on ad libitum energy intake

Note: There are buzz-words even in the title of this paper which make me uncomfortable!

As Raphi and I discussed, studies do not arrive out of the blue. Hall knew exactly how to set this latest CIM "destroying" study up. The rival camp (Ludwig's group are current torch bearers here) have pointed out that in short term studies that CICO applies quite well. In longer term studies (over two weeks, and yes, of course Hall knows this) low carb has a significant ameliorating effect on the fall in metabolic rate associated with caloric reduction/restriction. As in:

Do Lower-Carbohydrate Diets Increase Total Energy Expenditure? An Updated and Reanalyzed Meta-Analysis of 29 Controlled-Feeding Studies

People may recall I've looked at Hall vs Ludwig in the past. Of the two camps I personally favour the one with the most honest approach to the data. My thanks to David Ludwig for updating me on this latest interchange within the on-going process.

Anyhoo, time to get the children's breakfasts and keep working on the house before the builder arrives on Monday, while working towards various deadlines off blog.

Peter

ROS (01) Insulins are ubiquitous in eukaryotes

I've had this paper lying around for years:

Role of Insulin-Induced Reactive Oxygen Species in the Insulin Signaling Pathway

Figure 4, shown below, sums up why it interests me

Brief aside: The role of glucose in generating ROS from mitochondria is, to me, extremely dubious. It certainly can occur but it needs the activation of the glycerophosphate shuttle, which doesn't get a mention. But the GPS is how we convert cytoplasmic NADH in to mitochondrially inputted FADH2, with ROS generation resulting from the raised FADH2:NADH ratio intrinsic to this conversion acting on the CoQ couple. It will apply in the presence of insulin, not isolated hyperglycaemia. If you slog through the refs trail (not good) you need to realise FBS = insulin/IGF-1. Also few people even think of fatty acids in this respect, a serious omission. Enough of mitochondria, back to the cytoplasm. End aside.

It's worth pointing out that the insulin receptor is thought to act as a G-protein coupled receptor which signals to an NADPH oxidase (probably NOX4) using a specific G protein. The NADPH oxidase generates H2O2 extracellularly (this becomes important in future posts) which re-enters the cell (some papers suggest there is a specific transporter) to oxidise cysteines on protein tyrosine phosphatases, disabling these enzymes. Without PTPases maintaining the suppression of insulin signalling both the insulin receptor and insulin receptor substrates autophosphorylate and so signalling takes off.

That's all pretty straightforward and is verging on textbook.

Nothing happens without ROS generation.

This led me down a rabbit hole, thinking about how primordial insulin signalling might be and how primordial the ROS generation might be. Is insulin core, with ROS as a second messenger? People may have noticed that the most basic signalling is what interests me.

How far back does insulin go? If we have a look at this review

Insulin-like signaling within and beyond metazoans

we can see that there is a recognisable insulin like receptor stemming from the common ancestor leading to both ourselves and sponges. That's pretty far back, marked by the blue lineage arrows in Figure 1 from the review:

Insulin signalling is thought to be present in most, but not quite all, metazoans (blue circle).

The review looks at the evidence for insulin signalling in yeasts, plants and a ciliated protozoan.

Sacchromyces has no suggestion of an insulin receptor. However it responds to exogenous human insulin with a response remarkably recognisable as the response of human cells to insulin.

Plants are more straightforward. They produce an insulin-like cysteine rich peptide which interacts with an insulin-like receptor to induce the effects typically seen in mammalian cells under insulin. In fact using this peptide on adipocytes produces exactly the same effects as human insulin.

Neither the "plant insulin" nor its receptor have anything in common with metazoan insulin/receptor protein amino acid sequences.

Except they have common "shape".  They are immuno-related. They look similar enough (shape/charge distribution) that they can be recognised by the same binding antibody.

Exactly the same findings are duplicatable in the ciliate protozoan T pyriformis as for the Sacchromyces yeast.

So. Different insulin-like hormones, different receptors. Genetically completely unrelated, but causing the cell to respond in the same way.

The simplest answer is convergent evolution, as suggested in the review. I think this is correct. But there is a deeply insightful comment towards the end of the discussion. Almost insightful enough, but ever so slightly not quite there:

"The convergent evolution of ligand-receptor pairs alone cannot explain however the biochemical similarities in the intracellular response to insulin observed outside metazoans, as illustrated above. One way to overcome this seeming inconsistency is by considering that independently evolved upstream components of pathways devoted to processing environmental information may have been tied to evolutionary conserved core metabolic and cellular growth signaling networks".

The most obvious metabolic signalling molecules which adjust core metabolic function and cell growth are the ROS.

Metazoans, plants, yeasts, protozoa; all will use ROS signals to control metabolism and growth. This is the evolutionary conserved process on to which various environmentally responsive ligands and receptors have been co-opted to respond. On at least four separate occasions. My opinion.

A eukaryote is a derivative of a bacterium living inside an archaeon. Information about archaea is remarkably thin on the ground. I expect them to use ROS. Bacteria are more rewarding once you turn to Pubmed.

Perhaps bacteria are where we should be looking to find the origin of the primordial ROS signal.

Peter

Where the UK is heading perhaps (or not)

From January 13th 2021, early in Lockdown 3, UK.

This is Dr Mary Ramsay, head of immunisation for PHE (Public Health England, UK government). She is reiterating exactly the manifesto of the Great Barrington Declaration. I think it was April 2020 that I heard Prof Sunetra Gupta first advocate this concept. Now, in the early days of Lockdown 3, suddenly there is a voice of reason from a government department. It's echoing Vallance/Whitty from March 2020, before they both had all of their immunology knowledge, presumably with most of the rest of their brain function (sarcasm warning again) removed, sometime during Lockdown 1.

Here it is! (I can't see any way to embed and preserve Dr Ramsay's interview clip), it's in a Great Barrington Declaration tweet here

https://twitter.com/gbdeclaration/status/1349483284632375299

This is the text from the tweet because I always worry tweets may be ephemeral:

"Head of Immunisation for @PHE_uk -Dr Ramsey announced to the Science & Technology Committee that England may follow a focused protection strategy, where protection is given to the vulnerable and the disease is allowed to circulate among the young where its not causing much harm."

The text is true to the verbal narrative in the short clip.

While I'm on the subject of brain removals, people may be aware that daily COVID-19 deaths are currently exceeding those in the spring epidemic in the UK.

at a time when all-cause mortality is absolutely normal for the time of year, as mentioned in the last two posts. As in:

April was something exceptional. If anyone thinks December is in any way comparable to April you can head to the Funny Farm now. That's you, Prof Whitty.

Current COVID-19 death "data" are being used as an excuse for our government, particularly Matt Hancock (the UK Health Minister), to personally incite supermarket store managers to bully and harass people with mask exemptions into wearing masks in-store, if they want to buy food to eat. Apparently further measures are under consideration, god only knows what they will be.

Disgust is too mild a word.

I wonder whether Dr Ramsay will last at PHE? Perhaps the Guardian could run a hatchet job on her.

Peter

Just an update

Here is the right hand end of the graph from the last post, showing the partially adjusted all cause mortality for the UK in week 52:

Clearly the down tick at the end is the result of PHE struggling to adjust for the incomplete data from a week with a bank holiday followed by a week with two bank holidays. Paperwork, such as registering deaths, tends not to get done at weekends or on bank holidays.

So, theoretically, we could have had any of the red dashed line corrections:

EDIT We now have the 2021 week 2 report with more delayed registrations included. Looks like all cause mortality is now on a par with 2017/18. Still watching...

END EDIT

What happened when the majority (most, though not all, comes through within a week) of data were added in? On the 7th of January an update was posted so here is the original graph directly alongside the new graph. Again, ignore the downstroke:

If anyone is struggling to see the difference I've circled the important areas in red:

To put the current situation in to perspective I've pulled the curve from the last years during which we had a significant winter flu epidemic, 2017/18:

and just to make it even clearer, here's a line to show peak all cause mortality from 2017/18 vs end of Dec 2020:

It's also worth noting, again on a terribly parochial UK basis, that the winter peak in all cause mortality is almost always at the end of the first week of January. As in now, though the numbers will take a week or two to fully come in. This year may be typical, it may not. So far it's typical.

I have absolutely no doubt whatsoever that work in the ITUs (which are busy but not full, on a national basis) is hell at the moment. In hot-spots, worse. Given the level of barrier nursing needed, staff shortages because people are not allowed back to work until they eventually become PCR-ve (which can take months), social distancing within wards etc life must be awful and exhausting. 

I absolutely stand ready to accept that there is a catastrophe ongoing at the moment. It is quite possible that this winter's peak deaths will exceed that of 2017/18.

So far it hasn't.

I would suggest that the Guardian and the BBC may not be the most reliable sources of information about the current situation in the UK.

Just sayin'.

Peter

Another (as so often!) addendum:

Here are the ITU admissions for COVID-19 from ICNARC (which I consider to be unbiased reporting) up until just before Christmas:

which looks pretty grim, despite UK ITUs being at under 100% occupancy. But these are just COVID-19 patients. I don't have a similar curve for non-COVID-19 patients, but I do have this graph which includes both groups (and the rest of England), should they go on to die:

The last column is too low in both death categories due to delayed reporting, as always.

It's quite clear that for every death from COVID-19 there is nearly one less death from anything else. It could be that the virus is so lethal it is impossible to die quickly enough from anything else before it gets you.

Or it could be that managing to get a SARS-CoV-2 PCR-ve death certificate is becoming harder and harder to achieve in a hospital setting when PCRs are still being run to 45 cycles during a winter of endemic COVID-19.