Essential for life

Everyone talks about cholesterol, the good one and the bad one that causes clogging of the arteries, but very few people know the vital role of cholesterol in the human body. Cholesterol is present in all the cells of the body. It is an essential element in the composition of the cell membrane (external layer of the cell), as it plays a major role in its integrity and function.

It is also involved in the manufacturing of hormones, in our defense system against infections and in digestion (bile).

We all manufacture cholesterol

How can it be so important and have such a dangerous potential at the same time?

It is all about balance and the quantity of cholesterol in the blood. Every day, our body makes cholesterol in the liver; it is called endogenous cholesterol. The quantity produced varies from one person to another. We have a manufacturing “regulator”.  The setting of this regulator is genetically predetermined.

We eat cholesterol

The other source of cholesterol comes from food, it is called exogenous cholesterol. It is absorbed by the bowels and it is directed to the liver.

Transported in the circulation in ‘’taxis”

Absorbed and manufactured cholesterol is released into the blood circulation via carriers or ‘’ taxis ‘’. The good ‘’ taxi' ‘or good cholesterol is called HDL, the bad ‘’ taxi’ ‘or bad cholesterol is called LDL.

Bad cholesterol, LDL, transports cholesterol from the liver to the cells of the human body. Cholesterol in excess in circulation is brought back to the liver for its elimination by the good cholesterol, HDL.

Streaks in the artery

Even at young age, the transport of cholesterol starts to leave streaks on the wall of our arteries. With time and age, these streaks thicken in the walls of our arteries and may form plaques.

Formation of the cholesterol plaques

Plaque formation starts with the deposit of the bad cholesterol on the thin interior layer of the blood vessel, the intima. It is absorbed and stored in the muscular layer of the vessel, the media.

Its presence produces inflammation.

The presence of cholesterol in the media creates inflammation. It is grabbed by the macrophages, cells known to clean the body. They fill with cholesterol and then become trapped in the wall of the vessel. One can imagine them as large cells filled with scum.  When they die, they release their contents, which create even more inflammation, and then the cycle is repeated.

Accumulation raises the intima

The accumulation of cholesterol raises the intima and creates plaques. Like a pimple, the plaque surface is stretched and becomes fragile.  The inflammation caused by the presence of cholesterol in the walls of the arteries also activates the repair mechanisms of our body. This lead to fibrosis (thickening), which make plaques more rigid and firm. With time, calcium deposits may also appear.  can appear.

These plaques will increase in number and in size according to the excess of bad cholesterol (LDL).

LDL “taxis” are bad too

The bad cholesterol “taxis” (LDL) also contribute to plaque formation. Like pollution caused by our cars on the roads, certain proteins that are parts of the “taxis” also produce inflammation.  

Researchers are currently interested in these proteins, with the goal of finding a medication that could to reduce their number and thus have a beneficial impact on cardiovascular health.

What are the causes for LDL excess ?

Generally speaking, excess of bad cholesterol (LDL) comes from:

• Bad dietary habits, especially ingestion of saturated fat
• Predispositions (genetic, risk factors)
• Certain diseases (kidney and thyroid)

Reduction of the bad cholesterol is possible

The reduction of the bad cholesterol (LDL) can be done by following two principles:

1.Better lifestyle

• Balanced diet, low in saturated fat
• Regular physical activity
• Weight loss or maintenance of target weight

2.Medication

If improvement in lifestyle is insufficient to reduce the bad cholesterol (LDL) and if there is predisposition (risk factors) to coronary artery disease, a medication may be used. In the presence of coronary artery disease, the use of medication may be necessary.

Next chapiter: Understand the cholesterol screening