Hyperlipid by Petro Dobromylskyj
28 March 2020You need to get calories from somewhere, should it be from carbohydrate or fat?
This paper is from Hughes and Gottschling
An early age increase in vacuolar pH limits mitochondrial function and lifespan in yeast
It got a mention in the blog back in 2012 when it was freshly published. The group have gone on to study yeasts, ageing and the lysosome-like vacuole of yeasts. Their core finding is that vacuolar pH controls mitochondrial "health" which controls ageing, at least in their model.
The group has been very busy and earlier this year this paper was published from Hughes' lab:
Cysteine Toxicity Drives Age-Related Mitochondrial Decline by Altering Iron Homeostasis
The paper describes a very long series (way too many to detail here) of experiments aimed at adjusting vacuolar pH upwards and downwards and observing the effect on the survival of mother yeast cells through repeated cell divisions (replicative age rather than chronological age, there are arguments about which matters most).
Bottom line: Acidifying vacuolar pH extends lifespan, reducing its acidity shortens it.
Why should that be?
Their next series of experiments demonstrated that cysteine toxicity was the driver of early mitochondrial functional decline secondary to loss of vacuolar acidity. Cysteine is normally harmless and essential for life. Your cells love it, just so long as it is within the vacuole (or lysosome in humans), not in the cytoplasm. It's kept there by a vacuolar amino acid transporter driven by the vacuole proton gradient. The pH gradient is generated using a vacuolar vATP-ase to pump protons from the cytoplasm in to the vacuole, using ATP. It's related to the mitochondrial ATP synthase but normally runs in reverse.
If, on a long term basis, vacuolar pH rises (ie the vATP-ase fails), cysteine is released from the vacuole in to the cytoplasm where it auto-oxidises, generating much too much hydrogen peroxide. This reacts with the iron-sulphur clusters of complex I and many other crucial enzymes in the mitochondria. In old age cysteine becomes toxic through vacuolar failure.
I've been interested in this for some time because Barja and Sinclair have both intimated that they are tending to avoid animal proteins in favour of low cysteine/methionine plant proteins. Cysteine is the cellular executioner when vacuole pH rises during the old age of yeasts or lysosomal pH rises in ageing mammalian cells. It's interesting because methionine restriction (which reduces cysteine levels) appears to core to the longevity promotion seen with caloric restriction or protein restriction in mice fed on crapinabag.
You have to wonder whether we are looking at this the wrong way round. What if crapinanbag, based on starch and sucrose, causes early onset lysosomal failure which can be ameliorated by removing the cysteine, which is the cellular execution mechanism?
This would make methionine restriction's longevity extension rather specific to glucose based metabolism. My biases would tend to favour this point of view. There's no data, yet.
As an aside:
Now, I have speculated that both influenza and corona viruses need anabolic processes generated by mTOR activation. This requires acute acidification of the lysosome. Blocking acute lysosomal acidification is one technique currently being investigated for treating the life threatening pneumonia which develops in susceptible individuals during the current COVID-19 pandemic. There are suggestions that chloroquine, a suppressor of lysosomal acidification, might be an effective treatment. My guess is because it blocks anabolism.
There is probably a fine line between suppressing anabolism and releasing a mitochondrial-executing concentration of cysteine.
Neither Hughes nor Gottschling were considering therapeutic inhibition of vacuolar acidification as a stratagem for anything. They were more interested in avoiding long term loss of vacuolar acidity to delay mitochondrial function decline. But blunting anabolism without causing catastrophic cysteine release is a current anti-viral/anti-neoplastic therapeutic target.
You can see that the drug chloroquine a) might work and b) might be very toxic in overdose.
It does currently appear that it might work but we should never forget that "clinical experience is no guarantee of therapeutic efficacy".
However it would be great if it really did work.
Adult Respiratory Distress Syndrome is topical at the moment. In the comments to the last post I wondered whether omega six fatty acids, especially linoleic acid, might be a driver of ARDS, which is one of the most intractable ITU problems in response to major infection/trauma/inflammatory insults.
Tucker came up with this abstract
Plasma fatty acid changes and increased lipid peroxidation in patients with adult respiratory distress syndrome
and I peeked at the related papers to find this gem:
An increase in serum C18 unsaturated free fatty acids as a predictor of the development of acute respiratory distress syndrome
Again, only an abstract and mostly describing a pilot study. But here is the critical statement:
"Increases in unsaturated serum acyl chain ratios differentiate between healthy and seriously iII patients, and identify those patients likely to develop ARDS".
That is, the more linoleic (and oleic) acid you have as FFAs in your bloodstream, relative to my beloved palmitic acid, the more likely you are to develop ARDS. Which carries a high risk of death.
That was 1996. The work will have been done before that, so we have known that linoileic acid is bad news for well over 20 years.
If you are a Standard American on the Standard American Diet, or anyone else in the world poisoned by a cardiologist-promoted PUFA based diet, any weight loss through illness will release significant amounts of linoleic acid from your adipocytes. That might just trigger ARDS in the aftermath of a viral pneumonia.
There's a lot of it about.
BTW Steve Cooksey has a rather nice post up citing a lot of the refs featuring how to maintain an effective innate immune system, so as to avoid the viral pneumonia in the first place. It's a good read.
This press release, from 2013, surfaced on twitter (embarrassingly I have again lost the tweeter due a hat tip for this. Mea culpa. Found him, it was resurfaced/retweeted by Guðmundur Jóhannsson).
Glucose: Potential new target for combating annual seasonal flu
which summarises this paper:
Glycolytic control of vacuolar-type ATPase activity: a mechanism to regulate influenza viral infection.
Over the last few weeks I happen to have been immersed in vacuoles/lysosomes, cysteine toxicity, longevity and yeasts. Oh, and mTORC1, which is deeply associated with lysosomes. So I'm in a mindset of how lysosomes/mTOR control longevity/anabolism.
Anyhoo. Influenza A virus uses lysosomes to maximise its survival. My prediction is that it activates mTOR to induce a marked anabolic state and hijacks that anabolic state to generate lots and lots of influenza A virus particles. It will do that, much as a cancer cell might, by aerobic glycolysis working on the basis that glycolysis, while inefficient, is very, very fast at generating ATP compared to OxPhos. This would suggest that the free availability of glucose secondary to hyperglycaemia (or increased access of glucose to the cytoplasm secondary to hyperinsulinaemia) will increase the success of the influenza virus, as found in Kohio's paper.
Which brings us to anabolism and glycolysis. Not only does aerobic glycolysis supply ATP for anabolism faster than OxPhos can but it also supplies phosphoenolpyruvate for amino acid synthesis, plus other anabolic substrates come from glucose via assorted pathways.
However for every glucose molecule which generates a pair of 1-3 bisphosphoglycerate molecules two NAD+ are consumed. If these glycerate molecules are used for anabolism via phosphoenolpyruvate they will not restore the NAD+ balance by converting to lactate. The basic story is in
Cell surface oxygen consumption (2)
Cell surface oxygen consumption (3)
with an introduction to the concept in
Cell surface oxygen consumption (1)
The glycerophosphate shuttle won't do the job because this too is limited to the speed of OxPhos. Cell surface oxygen consumption does fit the bill for rapid restoration of NAD+.
So. Does influenza virus drive cell surface oxygen consumption to facilitate anabolism at a speed fast enough to keep it one step ahead of the innate immune system?
I don't know.
But another standard (primarily rodent) model RNA virus certainly does.
Oxygen uptake associated with Sendai-virus-stimulated chemiluminescence in rat thymocytes contains a significant non-mitochondrial component
I think this will be a basic feature of rapid anabolism, be that viral or neoplasia related.
Will hyperglycaemia and/or hyperinsulinaemia facilitate viral directed anabolism under infection by another, more topical novel human RNA virus?
Personally, I'm not planning on finding out the hard way when I get around to catching the current bug.
It came up in conversation with Ally as part of the Paleo Canteen podcast that I like coffee but that it doesn't like me.
Over the years before LC my coffee ingestion had stabilised at around 7 or 8 mugs per day. That's quite a lot. At the time I started on LC I did Atkins induction and cold turkey-ed from all methyl xanthines. The headache was tolerable, especially as I knew exactly why it was there and that it would be gone by about seven days in, which it was. The need for an evening stimulant also disappeared because I no longer fell asleep during the hyperinsulinaemic phase of the post prandial period.
For which I was infamous.
Over the years I have reintroduced coffee a couple of times but stopped it again due to either minor lower GI upsets or worsening of either low back pain or finger arthritis.
I had done a desultory Pubmed search to see if there was any evidence for clear cut, lectin induced GI damage from coffee which might explain my own signs. When the penny dropped that coffee "beans" were actually seeds rather than legume-like beans I sort of gave up hunting.
So I was avoiding coffee and expected to do so long term. My issue was that I quite like the jittery restlessness which comes from an acute large dose.
In the aftermath of chatting to Ally I received an e-mail for Mason about Dr Paul Mason, his local Dr in Sydney. I have a lot of time for Dr Mason and I really enjoyed his lecture from the 2019 Carnivory.com conference.
It turns out that Dr Mason is pretty sure there is a lectin in coffee. Not only that but the lectin is heat labile.
If you boil your coffee for 10 minutes you appear to pretty well destroy the lectin.
I can boil down a double strength cafetiere of coffee to the volume and bitterness of a double espresso in 10 minutes.
The caffeine is still there and absolutely produces the desired pharmacological effect.
For myself, drinking two or three double espressos per day produces tachyphilaxis to the caffeine within a week or two. Withdrawal is mild and sensitivity is pretty well restored within about 4-5 days. I have no interest in using caffeine to blunt caffeine withdrawal, so coffee is probably a weekend treat.
Plant poison, undoubtedly. Contains disgusting antioxidants too, no doubt. At the moment I feel that there is an acceptable trade-off.
For those who enjoy confirmation bias and worm studies:
Lifespan Extension Induced by Caffeine in Caenorhabditis elegans is Partially Dependent on Adenosine Signaling
Over the past few weeks I've been looking for papers where Barja's group might have run longevity experiments. This does not seem to have been their forte. They have done lots of observational comparative studies looking at long vs short lived species and lots of interventions to modify mitochondrial membrane lipid composition but no hard-core lifespan measuring studies that I can find.
So Barja threw in the rather off comment about avoiding "excessive intake of animal proteins and fats typical of western diets" in his review without obvious direct testing of these variables on lifespan.
I have to leave the mechanism of calorie restriction, aka protein restriction, aka methionine restriction for another day.
What we can do today is to look at Barja's dreaded animal fats. Like lard.
The data are, sadly, only available from CRON fed mice. This is the study:
The Influence of Dietary Fat Source on Life Span in Calorie Restricted Mice
Diets had their fat source modified thus and also had their calories restricted by 40%:
"The modified AIN-93G diets (% of total kcal) each contained 20.3% protein, 63.8% carbohydrate, and 15.9% fat. Soybean oil was the dietary fat in the control group (standard AIN-93G diet). The dietary fats for the CR groups were soybean oil (high in n-6 fatty acids, 55% linoleic acid, Super Store Industries, Lathrop, CA), lard (high in monounsaturated and saturated fatty acids, ConAgra Foods, Omaha, NE) and fish oil (high in n-3 PUFAs, 18% eicosapentaenoic acid, 12% docosahexaenoic acid, Jedwards International, Inc., Quincy, MA). To meet linoleic acid requirements, the fish oil diet contained 1% (w/w) soybean oil".
Here are the survival curves:
The left hand curve of green circles is from (nearly) ad-lib feeding of crapinabag. The yellow squares showing best survival are from feeding the dreaded animal fats from lard, combined with CRON. The fish oil group, full of EPA and DHA, did worst of the three CRON groups with soy oil being intermediate.
I think beef dripping would have done better than lard and beef suet even better still, but then I would think that.