Low carbohydrate, high protein and ApoE-/- mice

OK, here's the hot abstract from back in 2007.

And here's the press release from 2009, I've put the text up on my odds and sods blog as press releases don't last for ever on the net. The paragraphs are a bit chewed up but you can get the gist OK.

Cardiologists are impatient people. If they want to study aortic aneurisms they tend to do things like placing a balloon in the aorta via the femoral artery, inflating it and then pulling. Down the aorta, with the balloon inflated. Or they might go in there surgically, cross clamp the aorta in two places, perfuse the isolated section of aorta with some unpleasant chemical, then set all back to normal and try out the latest drug for aneurism treatment on the preparation. The prime requirement is the suspension of disbelief that the "model" has anything to do with human senile dissecting aortic aneurisms. It doesn't.

Obviously the cholesterol fed Syrian hamster is a great model for arteriosclerosis, but it's boring. There's nothing sexy about feeding a herbivore cholesterol. Sexy needs genetically modified mammals to make it happen.

So you want a mouse to get atheroma? Well, they don't. Feed them mouse chow and they get arterial damage and fibrosis all right, but not nice big juicy cholesterol filled plaque. What to do? Delete a gene.

One offspring from the impatience of cardiologists is the apoE-/- mouse. This mouse is a genetic cripple who's ability to process fat has been severely damaged. There are a very, very, very small number of people in the world who are homozygous for defective apoE. They are functionally apoE-/-. Nature does not allow this commonly. Contrast it with FH where there are hundreds of different types of FH, ie breaking your LDL receptor gene is easily done and evolution has not attempted to conserve it particularly highly.

Feeding a high fat diet to apoE-/- mice is bad news for the mice. Until anyone gives us the full text of the paper we'll have no idea of exactly what they fed to the mice but, ultimately, they broke the mice first. Actually, if Dr Murray is anything to go by, even the full text won't tell us much about what they fed the mice!

If you are apoE -/- I wish you luck. Statistically, you're not. Neither is the cardiologist, Dr Rosenzweig, who gave up his LC diet on the basis of this study. But then, he thinks the transgenic apoE-/- mouse is a model for human arteriosclerosis.

Peter

EDIT: OK, I now have the full text (thanks H) and here is the total information supplied in the methods section about the diets:

"Male pups were placed on one of the three study diets 1 week after weaning: standard chow diet (Harlan Teklad #2018 rodent chow), high-fat ‘Western’ diet (Harlan Teklad # 88137) and a custom-ordered low-carbohydrate diet manufactured to our specifications (Harlan Teklad)."

That's it. It is traditional to give enough information in the methods section to allow another group to repeat your protocol. If the problems in these mice are NOT from being apoE-/- then Foo et all are to be congratulated on developing a diet to produce more problems than the Western or Cafeteria diet, but they ain't telling anyone how to do it! No answer from Murray on the same query.

Prompt reply from Dr Rosenzweig with the table of diet compostion, just asking now about the Ca modification and if it involves PO4 changes