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Showing posts with label ends. Show all posts
Showing posts with label ends. Show all posts

Tuesday, August 2, 2011

Palmitic acid: the horror never ends

Chris forwarded me a link to this study. Read about inflammasones in tissue culture and quake. Here is the relevant line:

"These findings provide insights into the association of inflammation, diet and T2D."

It gets even better. Here is the best line from the press release:

"These results support the idea that inflammation plays a role in chronic disease," says Ting. "The simple message is to avoid fatty foods as much as possible."

OK, you take isolated cells, bathe them in 2mmol palmitic acid and they become unhappy. This is supposed to have something to do with eating a high fat diet?????

Just for fun I'm going, in my head, to eat some (gasp, horror) palmitic acid. Please don't do this at home, you probably don't want to inflame your inflammasomes.

I'm looking through my refrigerator for some palmitic acid but I notice that all there is in my fridge is Food. Bugger. What comes closest? Maybe butter??? Butter is undoubtedly Food, but it does have rather a lot of palmitic acid. Let's give it a try.

Half a pound of butter, here I come. Mmmmmmm. Nice. Yummie.

Now let's measure my blood palmitic acid levels . OOOOOh, post prandial triglycerides are up! Right on, I'm gonna die, some time soon. But what about the acid, the pamitic acid?

Ah, FFAs are also up up up. Success! 500, 600, 700, yes, 800micromol/l. If I really am in luck I might make that 2000micomol/l hit and drop right in to the inflammasome mediated diabetes zone. You know, that palmitic acid trip to nowhere.

Oh, but except for feeling a bit nauseous from all that butter in one go, I feel fine. Perhaps because I don't really have 2mmol/l palmitate in my blood stream after all. Double bugger. It seems like there is major, like MAJOR, contamination of my blood palmitate with oleate. Some is from the butter, some is from my own bloody liver cocking up the experiment. Using delta 9 desaturase to drop the occasional double bond in to long chain saturated fats ensures normal physiology.

Now, if I wasn't such a cheapskate I'd shell out the ackers to see if Ting et al used mixes of palmitate and oleate as well as either fatty acid in isolation. We know from the abstract that oleate does not inflame your inflammasomes... But I am a cheapskate, so I won't. Instead I'll go to this study:

"Low concentrations of oleate (0.1mM) completely inhibited palmitate-induced oxidative stress, SAPK activation, and apoptosis."

That's it, one tenth of one millimole of oleate completely negates the adverse effects of isolated palmitate.

Maybe check this one:

"Oleate alone did not cause mtROS generation and mtDNA damage, and its addition to palmitate prevented palmitate-induced mtDNA damage, increased total ATP levels and cell viability, and prevented palmitate-induced apoptosis and inhibition of insulin-stimulated Akt (Ser(473)) phosphorylation."

I could go on. No one, ever, at any time, has 2mmol/l of isolated palmitate in their bloodstream. A whiff of oleate is completely protective against the evil intentions of a researcher with a block of palmitate when viewed from the bottom of a test tube. It's called physiology. We are evolved to work this way. Knock out delta 9 desaturase and things become quite fun, but that's another story!

Citing the existing literature doesn't get you a Nature publication. Nor does it allow you to write press releases of utter stupidity to support low fat eating while simultaneously keeping yourself off the dole.

Peter

Palmitic acid: the horror never ends addendum

Okay, Victoria sent me the full pdf.

This group used 0.2mmol/l or 0.5mmol/l palmitate conjugated to bovine serum albumin. All other fatty acids were completely excluded. No semblance of physiological mixtures were involved.

But guess what, they had a living mouse model too!

Now you have to be wondering exactly how they managed to get a mouse to have 0.5mmol/l of palmitate in its bloodstream, to the exclusion of all other fatty acids, during a glucose tolerance test. After all, their test tube model used pure palmitate, surely they used the same conditions in their mice? This is a Nature paper after all.

How did they perform this near miracle? Well the methods section (when you finally find it tacked on to the end of the paper, an afterthought down beyond the references) doesn't mention any attempt to measure live mouse fatty acids at all. They didn't. WTF, this got published in Nature!

The diet used was good old commercial 5TJN. When I downloaded the composition pdf from the Test Diet website to my laptop it said I'd already downloaded it some time before..... It's popular!

Here's the link, it won't embed:

www.testdiet.com/PDF/5TJN.pdf

How much sugar would you like with your Crisco? Remember, always ask for your favourite lipotoxin by name...

NO NO NO.

JUST SAY NO.

Say no to Crisco.

As so often happens, this paper details feats of molecular and cellular manipulation of breathtaking complexity. How can anyone be capable of doing this and yet be so stupid? Awesome!

Peter

And it gets worse. The stats were done on "Prism 5.0 for Macintosh". OMG they're Mac users. It shouldn't be allowed. Their laptops should be confiscated forthwith. Now. I'll have them please.

Palmitic acid: the horror never ends speculation

Back in her PhD days my wife attended a seminar presented by a visiting researcher on some aspect of the inflammatory cascade. It was very technical and focused around the interaction of a certain ligand with its receptor at some critical juncture in whatever process they had devoted the last n years of their life to studying.

The ligand was all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid. No one in the room had any idea what this stuff was, certainly not the extremely intelligent presenter, other than as a molecular key to a molecular lock. It's a stock lab reagent purchased in research grade purity from any one of a number of suppliers. You could equally order cervonic acid.

At the level of reductionism these people can work at there is no need to be aware that all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid is available in gel caps from Holland and Barrett or is present in the nearest can of sardines as the more familiar DHA.

So imagine you are some newbie PhD student. You walk in to the lab and are handed a reading list a mile long. The lab has certain research lines you are going to slot in to, particularly focused around inflammasome activation by fatty acids. You got the post because you had picked up extensive experience with cell culture and inflammation research based around both endotoxin and asbestos, plus a track record of multiple Nature publications from your undergraduate work.

The lab you walk in to has cells in culture which go ballistic on exposure to utterly physiological concentrations of palmitic acid. At least six widely differing cell types behave in exactly the same way. This looks like a generic effect and puts palmitic acid up there with asbestos as a proinflammatory agent. You switch to Flora that very lunch time, and spread it thinly too.

The lab also has an animal house in the basement. The rats are either fed a standard lab chow or a red coloured greasy type of pellet oozing fat. The lab techs feed and water the ratties. Your job is to compare molecular aspects of white blood cell inflammasome activation as the high fat rats get fatter over the weeks. Once a fortnight someone brings you a blood sample to work with but, apart from that, you will never see the rats again...

What do you question? EVERYONE knows that eating fat makes you fat. Fat is fat. Do you give a monkey's about EXACTLY what is in the pellets which stain the tech's hands red when they do the feeding? It's a standard obesogenic high fat diet from www.testdiets.com. All obesity research uses it or something similar...

Would you sit down and work out whether the hydrogen atoms on either side of the central double bond of one type of fatty acid in one constituent of the 5TJN are aligned on the same side or on opposite sides of the bond? You know, cis vs trans configuration...

It's sloppy. It's possible. People will really be able stand up and say, as Ting does:

"The simple message is to avoid fatty foods as much as possible."

They probably have no doubts. They believe. It's complete bollocks of course. But I have this concept of how things work...

Peter

Sunday, July 31, 2011

Making ends meet

Not the kind of foods I would recommend, but still an amazing mother. She feeds a family of 6 with 4 dollars a week.