Lipoprotein( a) - Causes, symptoms and treatment. MF.

Lipoprotein( a) is a substance consisting of a protein and lipid part and is the main transport form of lipids in the body. It is synthesized in the liver and lipid composition practically does not differ from low-density lipoproteins, however, it contains more protein.

Preparation forResearch :

Material for the study of serum. Blood is collected from the vein into a vacuum tube, immediately after taking it to the laboratory.

Preparation of the patient - fasting for 12 hours, exclude hormones, nicotinic acid, phenytoin.

Reference values ​​of the content of lipoprotein( a) [LP( a)] in blood serum - 0-30 mg / dl.

LP( a) consists of apo( a), which is inherently glycoprotein and covalently linked to apo-B100.LP( a) has a significant structural similarity with plasminogen. LP( a) is larger than LDL, but has a higher density compared to them and has an electrophoretic mobility of pre-β-LP.On lipid composition, LP( a) does not differ from LDL, but protein in LP( a) is greater. LP( a) is synthesized in the liver. All modern immunochemical methods for determining LP( a) in fact reveal a protein - apo( a).

Increased concentration of lipoprotein( a) in serum is a risk factor for the development of IHD.According to the literature, the average content of apo( a) in the blood of patients with ischemic heart disease is 12 mg / dl. In 2/3 of the patients, the development of atherosclerosis depends on the presence of elevated concentrations of lipoprotein( a) in the blood. A close correlation was found between the concentration of lipoprotein( a) in serum and the development of IHD.Epidemiological studies have shown that in individuals with normal cholesterol concentration, but with an elevated level of lipoprotein( a)( above 30 mg / dl), the risk of developing coronary heart disease is at least 2 times higher. The risk increases by 8 times, if the concentrations of LDL and LP( a) are simultaneously increased. Myocardial infarction develops 4 times more often in young people, to which the content of apo( a) exceeds 48 mg / dl. In patients with obliterating atherosclerosis, the content of apo( a) is also increased.

The concentration of LP( a) in the blood increases after surgical operations, in patients with oncological diseases, in diabetes mellitus, acute phase of rheumatism.

The similarity of the structure of apo( a) and acute phase proteins makes it possible to treat it as a specific acute phase protein in destructive atherosclerotic processes in the vascular wall. Definition of LP( a) - an evaluation test for the activity of the atherosclerotic process. Its content in the blood correlates with the area of ​​atheromatous lesion of the aorta, the level of hyperglycemia, the time of blood clotting and markers of excretory excretory renal function. Arterial hypertension in atherosclerosis is often combined with an increase in the concentration of lipoprotein( a) in the blood.

The concentration of LP( a) in the blood is genetically determined, and currently there are no drugs that reduce it. In this regard, the only strategy for treating patients with elevated concentrations of LP( a) is to eliminate all other risk factors for IHD( smoking, overweight, hypertension, high LDL concentration).

Currently, there is a clear correlation between the concentration of total cholesterol in the blood and the mortality from cardiovascular disease. When the cholesterol level in the blood is below 200 mg / dL( 5.2 mmol / l), the risk of developing atherosclerosis is the least. If the LDL-C concentration in the blood is below 100 mg / dL( 2.59 mmol / L), heart damage occurs very rarely. An increase in LDL-cholesterol above 100 mg / dl is noted when eating foods rich in animal fats and cholesterol. Malnutrition, smoking and hypertension are synergistic factors that increase the risk of coronary heart disease. The combination of one of these factors with any other for about 10 years accelerates the development of a critical degree of coronary atherosclerosis. Reducing the concentration of total cholesterol in the blood and increasing HDL-cholesterol reduces the rate of progression of atherosclerosis. Reducing the concentration of total cholesterol in the blood by 10% leads to a reduction in mortality from heart disease by 20%.An increase in HDL-CI concentration of 1 mg / dl( 0.03 mmol / L) reduces the risk of coronary pathology by 2-3% in men and women. In addition, regardless of the total cholesterol in the blood( including more than 5.2 mmol / l), the inverse relationship between the content of HDL-C and the frequency of cardiac pathology remains. Concentrations of HDL-C( less than 1.3 mmol / l) and triglycerides in the blood are independent prognostic indicators of the probability of death from coronary heart disease. Therefore, the content of HDL-XC should be considered a more accurate prognostic indicator for mortality from coronary artery disease than the concentration of total cholesterol.

Laboratory test - Detected pathology
TG + XC-50%
TG + XC + HDL-XC - 57%
TG + XC + HDL-XC + apo-A 72%
TG + XC + HDL-XC + apo-A, + apo-B - 92%
TG + XC + HDL-XC + apo-A, + apo-B + LP( a) - Up to 100%

The following aspects should be considered in clinical practice.

• Reducing the concentration of LDL-C and increasing the concentration of HDL-cholesterol reduces the incidence of atherosclerosis.
• The ratio of "total cholesterol / HDL-cholesterol" is normally 3.4, to 75-89 years it rises to 4.7;the ratio 3.5 is considered optimal, and for 5 and more the risk of CHD is significantly increased.
• The lipid profile is directly related to the dominance of testosterone in men and estrogens in women.
• The concentration of LP( a) in serum reflects the activity of the atherosclerotic process.
• Excessive nutrition, obesity, smoking and low physical activity have an adverse effect on the lipid profile.
• Correction of lipid disorders should provide for not only a decrease in cholesterol concentration, but also normalization of the unfavorable lipid profile.
• Weight loss and physical exercise increase the concentration of HDL in the blood, and LDL-C and triglycerides - reduce.
• The development of atherosclerosis begins at a young age, so its manifestation at later stages of life can be prevented, leading a healthy lifestyle from a young age.

The optimal cholesterol-lipoprotein profile provides the next level of serum levels.

• Total cholesterol is less than 200 mg / dl( 5.2 mmol / l).
• HDL-XC - more than 50 mg / dl( 1.3 mmol / l).
• LDL-XC - less than 130 mg / dL( 3.4 mmol / l).
• Triglycerides are less than 250 mg / dL( 2.3 mmol / L).

Elevated levels of lipoprotein( a) in the blood are associated with a high risk of developing coronary heart disease, as it promotes the progression of atherosclerosis with the formation of plaques in the coronary vessels. In addition, there is always a high level of lipoprotein( a) in patients with obliterating atherosclerosis of the arteries of the lower extremities, atherosclerotic lesions of the cerebral vessels. Of the other conditions in which the content of this indicator is increased, it should be noted diabetes, some oncological diseases, and also the first days after surgery( in this case, lipoprotein( a) reacts like a protein of the acute phase of inflammation).

A decrease in the amount of lipoprotein( a) is usually observed in hyperthyroidism( increased synthesis of thyroid hormones), severe liver disease with signs of liver failure, prolonged starvation and cachexia( exhaustion), malabsorption syndrome( intestinal absorption disorder due to various causes).