Cholesterol: Role in vascular disease

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The word cholesterol seems to evoke a negative reaction, but cholesterol is actually functional. Cholesterol is a waxy lipid. The specific chemistry and molecular structure is here:http://www.heart-disease-bypass-surgery.com/data/molecular/m15.htm

I am writing from memory and so correct me if I am wrong about the following functions, as their may be me more:

1.) Cholesterols insulate nerver fibers
2.) HDL cholesterol protects the interior coating of arterial walls
3.) Cholesterol plays a role in cell wall maintainence
4.) Cholesterol helps maintain body fat, and so it is therefore functional
in relation to fat function (insulation, energy stores, protection of organs)

The negative conotations around cholesterol are come from damage done by the low density sort of Cholesterol. LDL (Low density lipoprotien.) these are packaged by flabby livers, or they are the unfortunate products of poor genes, and how they play a role in the packaging of lipoprotiens. Which is which? Find out. ( Getting a fasting lipid profile. See your family history, and make some changes in life style, and then recheck your cholesterol and lipid profiles. )

LDL in higher concentrations in the blood damages the inner layer of arteries.
If the cholesterols could be visualized this way,it would help to understand the differences in Cholesterols. Think of LDL as like a ping pong ball with spikes on it, like a Knight's mace. And HDL, (High density Lipo Protein) as like a normal round smooth ping pong ball.

Using this analogy we can see how high concentrations of LDL with high total cholesterol and low HDl can do damage over time. The LDLS scrape that cells that make up the arterial lumen walls and cause inflamation. It is the spikey part doing it. This damage causes white cells, called "macrophages." to move into the area, d they gobble up the LDLS as though they were foriegn objects. They can become so engorged that they explode leaving displaced muscle cells buldging into the lumen of the artery. Over time, multiple areas buldge out, leaving a narrower space for blood flow. Then plaques build up on the surface of these buldges. Add to that, as we age, the muscle walls become less elastic. They don't expand as they once did. (Now you know one mechanism of high blood pressure.)
A stable blood volume is now pumped through a more tortorous, narrow, and less elastic aretery.

In time we get a narrow occluded less elastic vessel carrying blood cells and platelets under higher pressure. Secondary to this evolving occlusion and less elasticity we have a recipe for disaster. One that could occur in any area of the body, a clot in the coronary, carotid, or peripheral vessel. (Are you at risk? Have a look at your legs if you are male and over 40, are they hairy, or ghostly white and hairless?. If it's the later see your doc,you have peripheral vascular diesease. But, don't panic, you are not alone. (Go to the beach and watch the hordes of men, fifty years or older with hairless legs.)

How does a clot lead to emergency?
It is a series of cascading events:

Disruption in blood vessels causes platelets to aggrigate to the area, to plug up the damage. Platlets and red cells smashing into this occluded area under much higher pressure, release tissue thromboplastin,which activates other clotting mechanisms. So, we get a clot. With clot formation we have partial or total occlusion, resulting in anoxia occuring in the tissues fed by that artery, ones are distal to the clot. In the heart, clot formation in the spaghetti like vessels that feed it (coronary arteries) leads to heart attack, in the carotids, it's a stroke, as the brain is now compromised. In the periphery, it is arterial thrombosis. A clot that forms in the periphery can break lose and end up in the lung, that is a pulmonary embolism. A potentially lethal event.

In general there is no way to avoid this process. It happens to us all as we age. But, we can reduce the rate at which it occurs. This can be done by lowering cholesterol levels and/or changing the ratio of HDL/LDL and by reducing cardiac risk factors. (These will be defined below.)

Normal cholesterol is < 200 mg/dl on fasting. My cholesterol is 150. It seems fairly stable at that level. But my LDL is not so hot, 40 mg/dl. I am age 60. It would be ideal if it were higher, 50 mg/dl. It would not be a good profile if my cholesterol fasting was 250.

But of interest is the fact that there are people who have very high cholesterol but they also have very high HDL, and they don't seem to develop coronary artery disease as quickly as in some cultures (some provinces of northern Italy were studied.)

This is because the HDL removes high serum LDL and directs it to the liver to be broken down.
LDL doesn't float so well in the blood, it is packaged poorly by the liver. It's sharp edges rip up the artery walls in high concentration.
LDL can be lowered by raising the metabolic rate in the liver. Livers can get flabby, and one way to package more HDL is to excercise. Smoking raises LDL and since I quit, my LDL has risen from 35.
But my cholesterol has always been low. (There isn't much cholesterol to be removed or much there to do damage. But I am not immune to this process, nobody is...) Some of what accounts for higher cholesterol is genetically determinded. Also Cholesterol isn't in the blood only because it is ingested.
Cholesterol is manufactured in multiple sites in the body from fat. eleven of them.

Therefore, lowering fat intake as well as lowering dietary cholesterol is part of the cholesterol lowering battle. (in particular partially hydrogentated oils used to fry foods, trans fats. )

Atheriosclerosis and Arteriolsclerosis are the two medical terms of relevance. The first is the build up of plaques along the interior artery walls. The second is the hardening of the ateries that results from scaring and age related processes...the loss of elasticity can lead to hypertension (high blood pressure.)
there are multiple causes of high blood pressure, and sometimes they are additive...meaning several
processes may be involved at once. For example: High renin output from the adrenal medula, causes contriction of blood vessels.

Blood pressure is a cardiac risk factor. The overall cardiac risk high or low, depends on a good idea of your baseline blood pressure. (By the way, have you doc take a few pressures. Many readings could be "reactive blood pressure" from anxiety. Chill out. Think about water falls, or a leave falling from a high tree. Make sure you are relaxed when the reading is taken. We don't want to see how your blood pressure is - when you are spooked. If there was lion in the room, you'd be abnormal if it didn't go off the map.)

If it is baseline high, it must be lowered. This is accomplished by dealing with separate issues that contribute to elevated pressure: disease states (ex: renal function), obesity and aterial damage. Medication is one treatment. Depending on the mechanism, a thiazide (water pill) calcium channel blocker (opens coronary arteries) or beta blocker ( decreases the effect of epinepherine from increasing heart rate too much.) Sometimes combinations are used.

Here are the controlable factors contributing to cardiac risk

1. Smoking (have to quit)
2. high blood pressure (medications and weight loss, managing stress)
3. high blood cholesterol (diet excercise and lowered fat intake, less cholesterol from food sources, if necessary medications)
4. Diabetes (early diagnosis, and proper treatment. This disease accelerates damage to arteries)
5. Being overweight or obese (10 percent of the world population is over weight. Taking in less calories than are burned. This is the only answer to weight loss. In general though we need more protein and less carbohydrate in our diet.
6 Compensate for sedentary lifesyles: .
We type away at computers and push buttons and sit on our duffs.
Few of us get up every morning to slop the hogs and plow the south forty.
And so, do we need a huge breakfast, of eggs, bacon and home fries?

6. Physical inactivity (30 min of low impact excercise per day, decreases risk: even walking helps. Get outside, and get off of the computer, your dog wants a good long walk. He will enjoy it, and so will your vessels.)

After fifteen minutes of low impact excercise, such as with a brisk walk, you stop burning sugar, and start breaking down fat. The muscles in you legs are the fat burning machines, using them in low impact excercise for 30 minutes per day, will begin to break down fat. This conversion of sugar to fat as a source of energey occurs after 10 to fifteen minutes of movement. A walk or a run or some aerobic form of excercise should be as regular a habit, as hygienge is...

We can't stop the aging process, and we can't alter our genes, but whether aging proceeds fast or slow, can be affected by maintaining weight. When changes are made, don't simply make them, monitor the effect - is the HDL/LDL ratio lower or high?

Factors that cannot be controlled involve:
family history of early onset vascular disease
heart attack and stroke. These can be compensated for by managing the lifestyle aspects already mentioned and with medications.

But, when doing this, you need to have a feed back mechanism. Ask you doctor to check your cholesterol before and after changes are made, cholesterol should be checked with total lipids and specialized tests that determine increased cardiac risk such as: hs CRP, Lp (a) and Lp -PLA-2
Diabetics should get regular HgbA1 C to monitor how effective glucose management is, as this test is an indicator of control over time. Regular checks are especially important when dietary changes are made. You want to know if the changes you make are working. Higher fiber in the diet, also, has been shown to lower serum cholesterol. Those prone to high LDL, and High cholesterol, can change the ratio, and the total cholesterol, and thus slow the damage to arteries.


Here are some informative pages on this subject:
http://www.cardioconsult.com/RiskFactors/
www.dietaryfiberfood.com/cholesterol-high-avoid.php
(Eating red meat is eating too much cholesterol. But, surprisingly one of the major components of arterial plaques, is poly unsaturated fats, trans fatty acids, and cholesterol esters, only 20 percent is
sat fat.

Overall, don't worry too much. Living, in time, is invariably hazardous to your health. But we can take some control and responsibilty for our health: as we are not always victims of disease. Simple changes go a long way. Fried food, should be a treat not a staple, this would apply to fast food as well. It is recommended that before starting any excercise program you get a stress test, if you have a family history of cardiovascular disease. The dog doesn't need one.