Now, recently Steve Sepel responded to our Basic Cholesterol 101; had a lot
of questions. One of the key ones though is interesting discussion: Dr. Brewer,
most people know or have heard the terms LDL and HDL but what are the real
differences between these low and high density lipoproteins? I've had done some
videos on the differences between LDL and HDL; I'll sort of skim through that
and then get into ApoA1 and ApoB. You see, ApoA1 is the proteins that
you find in HDL; ApoB is the protein that you find in LDL, VLDL, ILDL and
chylomicrons. I threw out a lot of names there, let's go back and simplify: HDL
just stands for high density lipoprotein. Why is it higher density than LDL which
is low-density lipoprotein and for sure higher density than VLDL which is very
low density lipoprotein? By the way, ideal is intermediate density lipoprotein (ILDL) it's
density between LDL and VLDL (very low density) - So, why do we separate the
cholesterol families and values out that way?
Well, here's why: Well, we can because we can. We start measuring it and looking at
it and what we found is that these HDL - as they increase in the - in the blood
testing, the patient tends to be healthier; with less heart attack
experience and less plaque. In fact, you may have seen from the Framingham
studies that HDL appears to be far more important and far more helpful than LDL
is (in terms of danger) This fractionation demonstration - also, it
includes the VLDL that I mentioned. The LDL, HDL, chylomicrons that I mentioned
which are huge, big, fluffy items that are full of cholesterol - and this sdLDL
which is small dense LDLs. Those are the dangerous ones. And Lp(a); I've got
several videos on Lp(a) - a genetic variation of
LDL; and it's got those kringle repeats forming a little hook that we think may
cause some of the problems. Now, we used to say that small dense LDL was the most
dangerous because it could slip through injured or around injured into most
cells. Recent research shows that SD - oxidized as small dense LDL actually is
transported through that intima layer. So, again, a little bit of a change didn't
change the vast majority of what we know but, again, creates some more opportunity
on understanding this. Just briefly, I've shown this a couple of times in
different cholesterol tests videos. This is that Lp(a) which - this is Brad
Bale. Brad has a cartoonist somewhere in his family and got the cartoonist to
do this video. The point behind this image is
this skinny guy (LDL) - bad cholesterol - saying "Why do I get all the attention?"
and his point here is a good one. His point is that you know there's some
other guys out there that are a bigger risk like - especially Lp(a) and
small dense LDL; covered a couple of items and helped put us into perspective
in terms of looking at the lipoproteins. One other quick point: what is a
lipoprotein? I've covered this, in case you haven't seen my other videos - just a
quick reminder: lipoproteins are proteins that are used to form microscopic
particles. So, when we eat a salad that has olive oil dressing, or a hamburger
that has fats in it, or avocado oil, or any type of animal or plant fat that -
those fats and oils don't form a big glob in our blood which is over 95%
water; everybody knows oil and water don't mix.
And what happens if you have big globs like this - the medical term for a big
glob is an embolus; and an embolus can - it gets stuck in the artery and cuts off
blood supply. That happens with like high speed wrecks where you
get multiple bones broken or it can happen with surgery as well, which is
also just a type of trauma. So, again, the body makes these proteins and these
proteins form microscopic pockets. This is the protein shell (a cholesterol ester
shell) and the protein that helps form that shell - the fats or oils are inside
that packet; same thing with HDL. Now, what's the difference? As usual, I have to
apologize for my visuals. This was a great picture but it's not that high
resolution. But the point here is: There are different proteins for the HDL and
LDL components. HDL has its higher density for two reasons: No. 1 - It's
got less fat, and No. 2 - it's got higher protein concentration. So that's
why HDL is measured as higher density. And that's also why these are both
called - all of these populations are called lipo (which means fat or oil)
proteins (which means protein) They're packets that are made up by the body's
protein which is made to encapsulate microscopic amounts of fats and oils
that are transferred by the blood. Now, what does "apo" mean? Well, let's go back
first and let's show this. You may notice - here's the point: ApoA1 - all of the
"good cholesterol" or the HDL family is made up of one type of protein - the
LDL families and the other "bad cholesterol families" are made up of
ApoB; so there are tests - laboratory tests which will show the difference between
ApoA and ApoB. Again, what does "Apo" mean? let's break down this - So this is a big
word. Again, like many other medical and Latin root words, you just get one
component of a word added to another - or suffix - and another prefix - and another
suffix; "Apo" means from or related to; or completing or part of. "Lipo" means fat or
oil. And "protein" - we all know what that means.
Lipos, fats, oils, cholesterol, triglycerides, fatty acids, protein - we
know what protein means; So, an "apolipoprotein" is a protein that allows our
blood to transport fats and oils safely. It is the protein part of a lipoprotein.
So, if you go back to this image, take away the rest of the lipid part and
leave the protein alone. That's apolipoprotein. Same thing here, under the
LDL, take away all of the cholesterol, lipids, fats, and oils, and just leave the
protein itself - and you get apolipoprotein B. As we said -
Apolipoprotein B is used in VLDL (the very low-density lipoproteins) intermittent
density lipoproteins, low-density lipoproteins, and chylomicrons;
Apolipoprotein A is used in HDL "the good cholesterol" ApoA1 is found in HDL
particles; its cardioprotective. It helps clear cholesterol away from arteries
that reverse transportation that you may have heard of. It's protective of
dementia as well. So, ApoA1 "Milano" is something that was discovered. They found
that people that had a certain type of ApoA1 in this area of Italy, actually
very near Milan, turned out to live to 80 to 100 years. They traced it back
to an individual near Milan a couple of hundred years ago. His name was Giovanni
Pomarelli and his descendants, people that trace back to him, tend to have a
very long lifestyle - I mean a very long life, given the fact that we're talking
about HDL here. Again, hopefully, it helps you understand that HDL is very
important to longevity. Now, there are people that have another variation of
ApoA1 - it's called E164X. They have big increases in premature
cardiovascular disease. If you take people that are - that have E164X of the
ApoA1 version of the ApoA1, they a significant plaque in their - all their
arteries in their mid-30s, mid-40s. So, again, significant thing to know about.
You can also look at the ApoB/ApoA1 ratio. That doesn't require fasting.
it's not affected by triglyceride levels. A high ratio may occur with a normal LDL
but demonstrate previously unrecognized risk. Moderate risk on ApoB or ApoA1
for men is 0.70-0.90 and for women, it's 0.60-0.80
Here's the ranges for those numbers. So, I hope this has been helpful.
Basically, what we looked at was a little bit deeper version of Apolipoprotein
I don't think that I covered what the labs look like. Those are the -
that's the simple part You get labs in there, show Apolipoprotein A1 and Apo-
lipoprotein B; and most of the labs that I get will also show Apolipoprotein A; but
you have to - usually, have to order that. If you've made it this far, thank you for
your interest. We're going to have a - an event: PrevMed only. Heart attack, stroke and
Prevention. Conference is November 8th and 9th at the University of Louisville
Conference Center. Hope to see you there.