Tuesday, July 23, 2019

On belief structures in lipidology (2) KODA-CP

Altavista put up an excellent link to an article describing an AI algorithm capable of mining pubmed abstracts and coming up with gold. The exact opposite of modern meta-analysis (repeat after me: the meta-analysis of dross is dross). And the AI algorithm could use old data to predict recent discoveries! Sadly, the university I graduated from is currently teaching final year vet students that any publication over five years old is unimportant/can be ignored. The end of science. Alt was prompted to share his gem following this link put up by Hap:

C‐reactive protein promotes atherosclerosis by increasing LDL transcytosis across endothelial cells

Which is worth thinking about (and ignoring). Unless anyone thinks that LDL transcytosis across human umbilical vein derived endothelial cells (HUVECs) in culture resembles the process of arteriosclerosis, I think we can safely ignore this aspect of the modelling in the paper. Just ask yourself how severe is venous arteriosclerosis, with or without C-reactive protein. And the cells in the model die if you expose them to anything greater than 35mg/ld LDLc! But it brings up the apoE-/- mouse, a truly fascinating subject.

The apoE-/- mouse is also a model. They develop hyperlipidaemia and rapidly progressive "arteriosclerosis". Obviously, the apoE-/- lipid particles, which lack their apoE attachment protein, work their way (using active transcytosis of course) through the endothelium of blood vessels and cause cholesterol to accumulate in the subendothelial space and... Well. It's a pretty neat evolutionary dead end, if you believe it.

The apoE-/- model tells us more than anyone could ever want to know about apoE-/- mice. I've just spent some considerable time on Pubmed and SciHub trying to find out if there is any sort of full blown apoE-/- syndrome in humans. Not apoE2/E2 etc, more like no apoE at all. Zero. Zilch. Like the mice.

No luck finding it so far.

EDIT Yay, Adam found it

Effects of the absence of apolipoprotein e on lipoproteins, neurocognitive function, and retinal function

No suggestion of CVD. Just shows how important adding over 1% by weight of dried (oxidised) egg yolk to the diet to generate the "model" might be!


But apoE-/- mice are interesting in their own right. They really do accumulate lipids on their arterial linings in a manner exuberant enough to make a lipidologist wet their knickers. None of this messing about with the non-lipid intimal thickening so characteristic of real human arteriosclerosis. Lipids, lots of them, just "invade" the arterial walls and stick. Right there, pretty well on the surface.


Every now and then you trip over an interesting paper, in this case about why apoE-/- mice really have vascular problems. Here's one:

TLR2 Plays a Key Role in Platelet Hyperreactivity and Accelerated Thrombosis Associated with Hyperlipidemia

The paper is long and complex and very, very clever. As per usual. And less than five years old.

Here is the scene-setter from the discussion

"Patients with enhanced platelet reactivity are at increased risk for cardiovascular events.4, 37–39 Enhanced platelet reactivity is associated with chronic and acute inflammation, infections, diabetes, and a number of pathophysiological states related to dyslipidemia, including atherosclerosis, diabetes, and metabolic syndrome". My italics.

The mechanism appears to be through CD36, a multifunctional scavenger-type receptor present on most cells but here they are looking at platelets:

"Previously we have linked platelet hyperreactivity in dyslipidemia to accumulation in circulation of specific oxidized phospholipids, oxPC-CD36, which activate platelets via the scavenger receptor CD36"

The "previously" citation is to:

Phosphoproteomic Analysis of Platelets Activated by Pro-Thrombotic Oxidized Phospholipids and Thrombin

which introduces us to KODA-CP, or to put it more elegantly 9-keto-12-oxo-10-dodecenoic-phosphatidyl choline. This was just one of the more effective CD36 activators of the many lipid products present in oxidised lipoproteins.

So. Hyperlipidaemia facilitates the generation of KODA-CP which activates CD36, which activates TLR2, which makes platelets super sticky.

KODA-CP must have linoleic acid or arachidonic acid as part of its parent molecule.

The platelets stick. In apoE-/- mice enough of them stick to form massive aggregates on the arterial surface that look a bit like late stage lipid infiltrated arteriosclerosis plaques. It's a model.

BTW, platelets carry apoB labeled lipoproteins, among the many physiologically appropriate contents of their cytoplasmic granules (link below). Under the more normal generation of arterial intimal hyperplasia which precedes pathology I consider this lipid will simply be used for normal repair/hyperplasia processes. But there is nothing physiological about apoE-/- mice. They look like they should stick a ton of platelets to any damaged vascular wall, with more apoB labels than any-(mouse)-body knows what to do with. Given enough omega 6 PUFA to generate the KODA-CP.

Apart from the cardiologist derived omega 6 PUFA (another link below), did you notice the core involvement of the CD36 receptor? CD36 also facilitates free fatty acid uptake in to many cells. It is stored within cells and translocates to the cell surface, a bit like GLUT4 proteins, when needed. Stored in the cell, translocated when needed.

What controls CD36 translocation to the cell surface?

Insulin, of course (another post there).

Just thought you might like to know.


Let's just summarise. Lacking the apoE protein limits the utilisation of lipoproteins, much as having a fully non functional LDL receptor does in familial hypercholesterolaemia. This increases the concentration of lipoprotein particles in the circulation.

Applying the Dunning-Kruger effect to lipidology: Lots of LDLc particles = lots of invasion. QED. That's been it for the last 50 years. I don't thing many lipidologists every get past this obvious, unarguable, simple fallacy. Oh, also core to lipid "therapy" has been, and still is, giving corn oil to lower the LDLc count.

In reality the elevated lipoproteins are a marker of reduced utilisation and are associated with an increased residency time in the circulation. Given lipids based on palmitic, stearic or oleic acids I don't think that would matter.

Given lipids filled with linoleic acid, the essential precursor of KODA-CP, you will get a progressive rise in KODA-CP associated with increasing persistence of the lipoproteins. The more KODA-CP the more activation of platelets via CD36/TLR2 (and undoubtedly other pathways) and the stickier the platelets become.

Given the pathological intake of linoleic acid promoted by cardiologists and lipidologists working under their cholesterophobic hypothesis it seems perfectly possible that seed oils (and insulin) may well be drivers of the platelet adhesion which is core to the vascular damage in apoE-/- mice. Platelets even carry apoB100 labeled lipoproteins in their cytoplasmic granules which allows us to immuno-stain lipid accumulations with this LDLc implicating flag.

Given lipoproteins which lack apoE on their surface, accumulation of KODA-CP, hyperreactive platelets and a surfeit of insulin we are in a position to understand how the apoE-/- mouse works. Which is cool for those of us who like to understand things.

How much of this applies to actual human arteriosclerosis? Increasing platelet stickiness will amplify the normal response to arterial injury. I think this may be real. The rest is just a very extreme, rather bad model.

Most models, like this one, are usually useless.

Is it conceivable that cardiological dietary advice represents the exact opposite of the correct approach? That it would actively worsen the problem it is aiming to ameliorate?

Yep. But we knew that anyway.

Increasing linoleic acid in the diet is undoubtedly a facilitator of the generation of KODA-CP and the activation of the subsequent cascade goes a long way to explain the Sydney Diet Heart Study and the Minnesota Coronary Experiment. People died. From corn oil.

I'll stop now.

Some helpful links that didn't integrate neatly in to the text.

Effects of saturated and polyunsaturated fat diets on the chemical composition and metabolism of low density lipoproteins in man (1980, written on papyrus)

Apolipoprotein B release from activated human platelets (1986, probably on parchment, safe to ignore).


bill said...

Even people on our side ("LCHF is good") are
getting it wrong:


See his cartoon at about 14:00

Peter said...

bill, yes, there are lots of variations. The bottom line is LC helps many problems, best not be too critical of people who see different shades of grey... Plenty to criticise among the detractors.


Bob said...

Hi, bill,

I watched the Paul Mason video and really found it very refreshing. Lots of the material has been here on Hyperlipid (for example, Lipoprotein(a) is oxidised cholesterol and Statins proportionately increase serum oxidised ldl). It's the first time I've seen some of these concepts discussed in a video.

If you read Peter Attia's long discourse on cholesterol, you'll see he mentions endothelial damage as part and parcel of the "LDL infiltration" of the artery wall. Same with Dr Spencer Nadolsky's article on Dave Feldman's website (Nadolsky follows Dayspring and Attia) as well Dr Mason in the video. They tend to gloss over it, but it's definitely mentioned. To his credit, Dr Mason blamed hyperglycemia. Probably simplistic, but still...Of course, Dr Kendrick has written at length on the endothelium on his blog, and he is no fan of LDL infiltration unless possibly it's Lp(a) patching a hole.

So I don't hold that one image against Dr Mason. He seems to be no fan of statins to keep the cholesterol down. We need more like him. Many more.

Geta said...

They used HUVEC instead of HUAEC?? I did load of cell assays myself, so I understand the need to save money. HUAEC are like double the price of HUVEC. They use what is available or borrow in exchange for authorship. But this? Plain stupid. Or maybe they did, and did not publish it. Just as common.


Passthecream said...

I wonder what that AI would make of the high levels of cognitive dissonance you find in the abstracts of lipid related papers? Probably would develop a severe Artificial Neurosis and start comfort binging on obesity research.

Peter said...

Geta, yes. But it is arteriosclerosis research...

Pass, yes materials science may be less confounded than nutrition. Maybe, maybe I'm innocent re superconductor design arguments!


karl said...

"Is it conceivable that cardiological dietary advice represents the exact opposite of the correct approach?"

Sadly, yes... They have blood on their hands from my point of view as a CAD patient.

I was just told I might consider a new-non-statin cholesterol lowering drug - sadly for the practitioner I pointed out the in the drug trials there were more deaths in the intervention group. (Deaths are a pesky statistic - hard to fudge the numbers). When I pointed out this detail - I was greeted with you poor old fool look.. facts don't matter.. The ungrounded narrative lives on - we have the zombie of the cholesterol-as-the cause kept alive by parroted narratives...

I am quite willing to accept that there are not effective treatments at this time - just stop this nonsense..

Passthecream said...

Karl, there may very well be effective treatments hiding in plain sight but with all of the zombie theories lurching about no-one is spending much time or effort looking at them. It's the medical equivalent if the politician's dogwhistle technique. Eg ' look out, there's a dangerous saturated fat, better take this flamethrower to keep it away.' Etc. You get the picture. It's all based on stupid fears and superstitions.

karl said...

@ Passthecream

It is even worse - Statins kill - someone with CAD gets a prescription of statins he is told will help ( possibly a bit true - perhaps a NO relaxing arteries effect - but very little help).

What if he was told instead, that there was not a good drug - but by keeping ones postprandial down to 110 - and regular intensive exercise (doing squats equal to ones weight 3x a week - running sprints to the point of being uncomfortably out of breath) actually does make a meaningful difference.

But if one swallows the narrative with the pill - how likely is the motivation for the exercise? - It is just to easy to think that the close to worthless pill is going to do it.

So my take is that statins kill by demotivating people from doing interventions that I estimate are about 1000x more effective.

Ran into this paper the other day:

And yes - you are right - this bogus theory - parroted about - keeps research money tied up that could be used to find new interventions.

If you look at the premise of the LDL kills world - it is based a a rather weak correlation - but correlations do not prove cause and effect - and even if you accept the linkage - what if the arrow of causation is backwards? What if the body is busy repairing damaged arteries and thus increases cholesterol? - just like in burn patients? (Or did the high cholesterol cause the burns?) And in spite of the annoying fact that ALL the other cholesterol lowering drugs don't work why do they still run blood tests??? Logic dictates that it must be a different effect that matters.

So much of medicine is based on weak correlations - but in biology everything interacts - claiming that X going up causes Y takes much more - but these correlations plus a bit of ego give rise to some narrative - birthing ungrounded narratives that circulate until they are 'common knowledge'

I suspect that about 50% of 'common knowledge' is wrong to some extent - and perhaps a further 10% is in the "not even wrong" category. Not just coronary medicine is based on Swiss cheese foundations.. it is everywhere.. They are still doing modern day versions of tobacco enemas.. blowing smoke .. The gap between what is in good research papers and the practice of medicine is huge.

Passthecream said...

110% enthusiastically agree and would add that Statins are not simply demotivating in the same way as the fiction of placebo but actively work to prevent those useful hands-on lifestyle changes. I was foolish enough to be convinced to take statins for a brief while until I found that I could turn the weird new problems i had off and on again by stopping and starting taking them. Zombie pills --> bin.

Passthecream said...

Karl, just when you think it couldn't get more ridiculous than blowing smoke up your ... ahem, there is this to consider.


As Spike used to say 'Halt! Who goes there, friend or enema?'

bill said...

Here's Ivor Cummins talking about how LDL
gets through the vessel wall. Again, on
our side, but completely mistaken:


altavista said...

Off-topic Peter, but want to know your commentary on this, please

Esp. Table S1 under Supporting information

Peter said...

Hi all, back from vacation.

bill, no time yet, I'll give it a listen when I can. Ultimately no two thinkers will agree on absolutely everything. So be it. No problemo.

alt, absolutely spot on. Anyone basing their diet on 40% of calories from corn oil need not expect to stay healthy. You have to giggle as to whether the mechanism might have been low LDLc. Probably not as mice are mice and do their own lipids. But 13-HODE, now there's a corn oil derivative...


altavista said...

How would the low LDL trigger it? Is there a post somewhere?
Care to speculate on the mechanism? Why would the intervention group insulin be double?
I was coming to terms that the culprit is excess fat around the pancreas from all the glucose, but corn oil?

Peter said...

alt, the neatest was a statin trial but there are others. Of course you can find studies which show no association too...



LeenaS said...

"How would the low LDL trigger it? Is there a post somewhere?"
If LDL particle size decreases, as via oxidising, it is a bad thing.
This seems to happen easily with high PUFA seed oils, which are oxidising, and which do remain a very long time in circulation, unlike saturated ones. Polyunsaturated oil = fragile oil = reactive oil.