Lipoprotein

The role of lipoproteins in the body

Lipoproteins are complexes of proteinsProteins are high-molecular organic substances consisting of alpha-amino acids linked in a chain by a peptide bond. In living organisms, the amino acid composition of proteins is determined by the genetic code. During synthesis, 20 standard amino acids are used in most cases. Many combinations of them determine the great diversity of properties of protein molecules. Proteins play a key role in the immune response and can perform transport, storage, catalytic, structural, and receptor functions. Proteins are an important part of the nutrition of animals and humans. The main sources of proteins are meat, poultry, fish, milk, nuts, legumes, and grains. (apolipoproteins) and lipidsthat transport fats (cholesterol, triglycerides) in the blood. They are divided into several types, each of which performs its own function:

1. The main types of lipoproteins

2. The main functions of lipoproteins

• Transport of fats (cholesterol and triglycerides) to cells.
• Maintaining the structure of cell membranes.
• Synthesis of hormonesHormones are biologically active substances that are produced by specialized cells or glands (such as endocrine glands) and regulate various physiological processes in the body. They act as chemical signals that are transmitted through the bloodstream to organs and tissues to control and coordinate a wide range of functions, including metabolism, growth and development, reproduction, mood, and more. Examples include insulin, testosterone, estrogen, and adrenaline. (steroid, sex, vitamin D).
• Participation in immune responses.

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Blood lipoprotein values (according to ESC/EAS 2023 recommendations)

Type	Composition	Function
Chylomicrons	Triglycerides (85-90%)	Transport dietary fats from the intestines to tissues
VLDL	Triglycerides (50-70%)	Deliver fats from the liver to tissues
LDL	Cholesterol (45-50%)	“Bad cholesterol” – transports cholesterol to blood vessels
HDL	Proteins (50%) + Cholesterol (20%)	“Good cholesterol” – removes excess cholesterol from blood vessels

Note:

• For people with diabetes, CHD, and atherosclerosis , the target LDL is < 1.8 mmol/l.
• LP (a) is a separate risk indicator, normally < 50 mg / dl.

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Lipoprotein deficiency (hypolipoproteinemia)

Reasons:

• Genetic disorders (abetalipoproteinemia, Tangier’s disease).
• Fasting, cachexia (cancer, anorexia).
• Severe liver diseases (cirrhosis).

Symptoms:

• Malabsorption of fats (steatorrhea – fatty stools).
• Lack of fat-soluble vitamins (A, D, E, K).
• Neurological problems (loss of coordination, decreased vision).
• Developmental delay in children.

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Excess lipoproteins (hyperlipoproteinemia)

Reasons:

• Poor nutrition (excess saturated fat, trans fat).
• Genetics (familial hypercholesterolemia).
• Hypothyroidism, diabetes, and obesity.
• Kidney diseases, alcoholism.

Symptoms:

• Atherosclerosis (heart pain, lameness, strokes).
• Xanthomas (fatty plaques on the skin, eyelids).
• Lipoid arch of the cornea (white rim around the iris).
• Pancreatitis (with triglycerides > 10 mmol / l).

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How to normalize the level of lipoproteins?

With elevated LDL/triglycerides:

• Diet: less animal fat, more fiber (vegetables, oatmeal).
• Sports: 150 min / week of aerobic exercise.
• Medications: statins (rosuvastatin), fibrates (fenofibrate).

With low HDL:

• Omega-3 fatty acids(fish oil, flaxseed oil).
• Smoking cessation.
• Moderate consumption of red wine (in consultation with your doctor).

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When should I get tested?

• After 40 years – once in 5 years (if there are no risks).
• For obesity, diabetes, and hypertension – annually.
• If relatives have early heart attacks/strokes.

Important: The doctor should interpret the lipidogram taking into account age, gender and concomitant diseases!