Hypercholesterolemia (Alterations in cholesterol and other fats)

Fats are an important part of our diet. Most of the fats that we ingest with our diet are called triglycerides and, to a lesser extent, cholesterol and phospholipids. All these fats will be absorbed in the small intestine and later used to form the membranes of all the cells in our body (cholesterol and phospholipids), manufacture hormones and bile (cholesterol), serve as fuel in our adipose tissue and in our muscle (triglycerides), and activate blood clotting (phospholipids).

In addition to their origin in the food we eat, the fats in our body are also produced in the liver (cholesterol and triglycerides); This happens when we are not eating or in situations of prolonged fasting.

However, these fats cannot circulate as such in the blood. Let us remember that if we pour water and oil into a glass, both substances do not come together but remain separate ("rejected"). The same would happen if we put a few drops of fat in the blood (which is basically water). For this reason, fats circulate in our blood "protected" by a protein covering that serves as a shield and allows this "fat" to reach all tissues to carry out the functions to which we have referred before. The set of protein and fat that it carries is called lipoprotein.

There are different lipoproteins, LDL and HDL being the best known, but not the only ones. The importance of these two lipoproteins lies in their association with blood cholesterol levels and their close relationship with the onset of cardiovascular disease. The cholesterol carried by LDL is distributed from the liver and reaches all tissues and is also deposited in the arterial wall; it is associated with an increased risk of atherosclerosis and cardiovascular disease, which is why it is popularly known as "bad" cholesterol. While HDL transport excess cholesterol from the arterial wall and from body tissues to the liver to eliminate or reuse it; HDL protects us against the onset of atherosclerosis and cardiovascular disease, which is why the cholesterol transported by HDL is known as "good" cholesterol. Although from a scientific point of view, "bad" cholesterol is essential for life, like water or oxygen; It is only "bad" if it is in excessive amounts in our body.

Other lipoproteins carry triglycerides; this is the case of chylomicrons and VLDL. Its function is to transport triglycerides to muscle and adipose tissues where they are to be consumed or stored until they are used.

Once used, fats are eliminated from the body or reused, and they do so mainly through the liver.

If a person has, for example, an inability to eliminate cholesterol, by doing a blood test we will see that their cholesterol levels are very high. The same if, for example, your intestine absorbs a large amount of cholesterol. At other times, what is elevated in the blood are triglycerides. And a third situation is when the cholesterol numbers are low. Finally, we can find a combination of these situations.

We know all these alterations globally as dyslipidemia, which will result in an alteration in the concentrations or levels of fats in the blood. When the levels of cholesterol in the blood are high we speak of hypercholesterolemia. When triglyceride levels are high we speak of hypertriglyceridemia. And when there is a combination of both, we speak of mixed dyslipidemia. We will also consider a low HDL cholesterol or hypoalphalipoproteinemia.

Hypercholesterolemia is the increase in the level of cholesterol in the blood above the values ​​considered normal. When we speak of hypercholesteroleromy we refer, by default, to the cholesterol that is included in the LDL or "bad" cholesterol. We establish normal cholesterol values ​​(total cholesterol) below 200 mg / dL (= 5.2 mmol / L). Normal LDL cholesterol values ​​will be defined according to the cardiovascular risk of that individual. There is no LDL cholesterol level in the blood below which the individual is fully protected from suffering from cardiovascular disease. In an individual in whom there are other risk factors for cardiovascular disease (for example, diabetes, hypertension, or smoking), lower levels of LDL cholesterol may be more harmful than in another individual without those same risk factors. In general, then, the higher an individual's risk, the lower the LDL cholesterol level should be. In epidemiological terms and in terms of cardiovascular risk reduction, it would be ideal if our LDL cholesterol were always below 130 mg / dL (= 3.4 mmol / L).

Hypertriglyceridemia is an increase in the level of triglycerides in the blood above the values ​​considered normal. As for cholesterol, there is no borderline figure for normality. But based on the associated cardiovascular risk, we establish as normal values ​​having triglycerides below 150 mg / dL (= 1.7 mmol / L); and from a point of view of the risk of suffering from pancreatitis, triglyceride values ​​should never exceed 400 mg / dL (= 4.5 mmol / L).

Hypoalphalipoproteinemia is the decrease in HDL cholesterol in the blood. Studies indicate that normal values ​​for HDL cholesterol are figures above 40 mg / dL (= 1.0 mmol / L).

How is it produced?

The causes of abnormalities in the concentrations of these fats are divided into two large groups: on the one hand, the so-called primary causes, which include alterations in certain genes that control the absorption, manufacturing and elimination pathways of fats. ; and, on the other hand, what we call secondary causes because they are dyslipidemia secondary to the presence of certain diseases, drug use or poor lifestyle habits such as smoking, alcoholism, sedentary lifestyle or obesity. In some individuals, both types of alterations may be present.

In what situations or diseases is LDL cholesterol increased?

The genetic disease that most frequently causes an increase in cholesterol is familial hypercholesterolemia, which is due to a mutation in the gene that codes for the hepatic LDL receptor, so that LDL cannot be eliminated from the bloodstream. Another genetic entity that also prevents LDL from being removed from the blood is familial apolipoprotein B100 deficiency. Among the secondary or non-genetic causes, blood cholesterol may be elevated by the consumption of a diet rich in fats of animal origin, by the consumption of some drugs (for example, certain diuretics) and by the presence of a disease thyroid (hypothyroidism), kidney (naphrotic syndrome) or liver (cholestasis).

In what situations or diseases are triglycerides increased?

Lifestyle factors such as alcohol consumption and diets rich in bakery products can lead to increased triglycerides in the blood. Certain diseases such as type 2 diabetes mellitus, obesity, chronic kidney failure and hepatitis are also secondary causes of increased triglycerides. The same as some drugs such as estrogens, beta-blockers, resins, and retinoic acid. Pregnant women can also have high levels of triglycerides in the blood. Genetic causes that increase triglycerides are less common, and among them we must mention the lack of a protein that breaks down VLDL called lipoprotein lipase, or combined familial hyperlipidaemia.

In what situations or diseases are cholesterol and triglycerides increased?

Among the primary or genetic causes are combined familial hyperlipidemia (where increases in cholesterol can also appear without an increase in triglycerides and increases in triglycerides without an increase in cholesterol) and type III hyperlipidemia (where there is always an increase in cholesterol and triglycerides). Secondary causes include any combination of those that cause an increase in cholesterol and those that cause an increase in triglycerides.

In what situations or diseases is HDL cholesterol lowered?

There are genetic causes due to mutations in certain genes that encode critical proteins in the synthesis and elimination of HDL, for example, familial hypoalphalipoproteinemia (common) or Tangier disease (rare). The secondary causes that lower HDL cholesterol are a diet rich in bakery products and refined sugars, obesity, type 2 diabetes mellitus, and smoking.

Symptoms

Cholesterol (both "good" and "bad" cholesterol) itself does not cause symptoms. An individual may have high levels of LDL cholesterol and surely those figures do not cause any symptoms, not even a simple headache. However, these high numbers will gradually damage the wall of your arteries (the arteries that carry blood to the heart, the arteries that carry blood to the legs, the arteries in the neck that carry blood to the brain, the aorta artery, the arteries that carry blood to the kidney and other arteries) until finally causing an obstruction to the passage of blood through those organs, or also a severe weakening of the artery wall (aneurysm). Depending on the location of the clogged arteries, the patient may have heart disease (angina pectoris, myocardial infarction or heart failure), cerebral thrombosis, chronic kidney failure, arterial disease of the lower extremities (intermittent claudication, gangrene), or abdominal aneurysm.

Cholesterol is also deposited in other tissues, such as the skin, eyelids, and tendons, and we call them xanthomas; or in the cornea, and constitutes the so-called corneal arch. In these cases, the accumulation of cholesterol only produces aesthetic problems.

HDL cholesterol, when it is low, does not cause symptoms either, but it will not be enough to eliminate cholesterol from the blood circulation and thus it will contribute to the aforementioned cardiovascular phenomena.

Moderately high triglycerides also do not cause symptoms, but they help accelerate the onset of cardiovascular problems. However, high or very high levels of triglycerides must be considered, since they are the cause of acute pancreatitis, that is, an acute inflammation of the pancreas that can be fatal. In this case the symptoms are severe abdominal pain that develops within a few hours.

Diagnosis

The diagnosis of hypercholesterolemia, hypertriglyceridaemia or hypoalphalipoproteinemia can only be made with a blood test. The presence of a cardiovascular disease or xanthomas in an individual will make us suspect it but rarely diagnose it and, much less, know the exact levels of cholesterol and triglycerides. The basic analysis consists of the fasting determination of total cholesterol, HDL cholesterol and triglycerides. If triglycerides are below 400 mg / dL, LDL cholesterol can be calculated using a simple mathematical formula. In the case of elevated triglycerides, the presence of chylomicrons in the blood should be investigated.

This way we will be able to know if the individual we serve has an alteration of blood fats and of what type is said alteration. In addition, the doctor will have performed a physical examination to look for xanthomas, corneal arch, and vascular murmurs. He will also be questioned about the family history of obesity, dyslipidemia, diabetes, hypertension, cardiovascular diseases already present or the presence of xanthomas; and a personal questioning on the same points, also including aspects such as menopause (in women), smoking, alcohol intake, diet and exercise, and the presence of some cardiovascular disease.

From an academic point of view, the analyzes should be repeated to confirm the anomalies found and take advantage of to make some other determination such as the function of the thyroid and the kidney and the liver if they were not available.

Treatment

The main objective is to avoid the onset of cardiovascular disease and its complications. In some cases the goal is also the prevention of pancreatitis. To do this, we must achieve blood fat values ​​and that these figures remain stable and sustained. But the figures to be reached should not be based only on the isolated value of cholesterol or triglycerides, but also on the presence of other risk factors, accompanying diseases such as diabetes, suffering from cardiovascular or kidney diseases, etc.

The correction of any disorder of cholesterol and triglycerides (regardless of the numerical values) involves changes in the eating pattern and physical activity and smoking cessation, to which may be added drugs and other measures that the doctor consider appropriate.

Currently there are several effective and well-tolerated drugs. The choice of drug must take into account the characteristics of the individual. The main drugs used to treat cholesterol and triglyceride disorders are statins, ezetimibe, resins, nicotinic acid, fibrates, and omega-3 fatty acids. Many patients require the use of several of these medications to obtain adequate control. of fats.

Precautionary measures

Conclusions.

Fats are a very important part of our life and our body incorporates them from food or manufactures them through the liver.

The problem arises when we have more of these fats in our blood than we need and they get deposited in the arteries and clog them. We can only detect high fat figures with a blood test. And in these cases we must put in place the mechanisms to reduce them and thus reduce the risk of cardiovascular disease and pancreatitis.