Pathogenesis of the atherosclerotic plaque and atherothrombosis

Coronary artery disease, the most frequent killer of middle aged males and lately rising numbers of females, has been a bane on mankind as it kills many unsuspecting important members of our workforce, many at the prime of their lives, leaving behind many families without their most important breadwinner.

It is therefore obvious that much work has been done to understand this disease and hopefully lead to better therapy and more importantly, to better prevention so that hopefully we can wipe out this deadly disease ( surely not in my lifetime, maybe in the next decade or two.

1. What is atherosclerosis, arteriosclerosis or arteriolosclerosis?

Arteriosclerosis is derived from the Greek word arteria, meaning artery, and sclerosis meaning hardening. -osis in Greek means a disease condition.

All the 3 terms may be used interchangeably, depending on the context. They mean the same.

When I teach, I usually like to draw my students' attention to how medical terms are derived from, so that they can better understand the context and thus remember the meaning better ( hopefully ).

So we are talking about hardening of arteries. Arteries of the body, the heart, the brain, the kidneys, the liver, the arms, the legs and even the small arterioles of the eye.

All these arteries when they age, they harden. They harden as they allow lipids, particularly cholesterol, to accumulate below the inner lining ( sub-intimal ) lining of the wall of the artery (the artery wall have 3 layers, viz intima, media, adventitia ).  Besides age, some disease conditions can also cause arteries to harden. Diseases like hypertension ( constant elevated blood pressure or tension, pounding the artery wall ), cigarette smoking, diabetes mellitus, and some genetic diseases can cause premature arteriosclerosis. 

2. How does arteriosclerosis form?

In this disease, the medical community put the cart before the horse. I suspect that there was this problem of people dying from heart attacks in the 50's and some saw the opportunity to make some money. Dr Ancel Keys, published the "Seven Countries Study", which basically showed the correlation between lifestyle, diet and heart attack rates and strokes in seven countries. Surely we all know now that CORRELATION IS NOT CAUSATION. Nonetheless "Fats. Cholesterol, Diets" Stigma has stuck since then, making some Pharma billions of dollars since the 60s till today. Cholesterol is bad, cholesterol kills, and bad cholesterol is the mantra for selling cholesterol-lowering pills for all and sundry regardless of of their benefits and harmful side effects.

What then are the facts?

We have to thank Dr Peter Libby and his team at Mass Gen Hosp. ( Boston ) for much of our current understanding. 

It is obvious that God gave us Cholesterol to help us, not to harm us. Cholesterol form the basis for all our tissues, cell membranes, sex hormones and our "stress hormones". Without a healthy level of cholesterol humans cannot survive and be "human". 

However, it is true that in some people, cholesterol ( particularly oxidized LDL-Cholesterol ) can accumulate just below the inner lining of our arteries, causing the artery lumen to be narrowed and so limiting blood flow, and be severely consequential, if this should occur, in arteries to vital organs. 

Besides risk factors that promote the adhesion of LDL-Cholesterol in the arterial intimal wall of patients at risk, to promote the initial phase of arteriosclerosis, there is also the important element of inflammation and inflammatory molecules and their important role in promoting arteriosclerosis as well as muting or damping down arteriosclerosis.

What is more important to emphasize is that artery blockages do not kill. They only cause warning chest pains which make us seek medical attention and so treatment. What kills is the inflammatory process that causes a vulnerable plaque and subsequent plaque rupture. which causes atherothrombosis and a heart attack. That can kill. Dr Ancel Keys and Pharma, had no inkling about this for 30 years while they promoted the "Cholesterol scare" and profited. 

Diseased arteries and blockages per se, do not kill. A blood clot on the blockage may kill.

IT IS ATHEROTHROMBOSIS ( a blood clot on the arteriosclerotic plaque ) THAT KILLS, NOT ATHEROSCLEROSIS.

And of course, medical science has never evaluated the importance of happiness as a means of lessening inflammation, and thereby lessening the risk of athero-thromosis?  

Be happy always is a good philosophy

Next blog coming soon. The Management of hypertension. What we got wrong for 3 centuries