- a group of substances that are heterogeneous in chemical structure and physico-chemical properties. In blood serum, they are mainly represented by fatty acids, triglycerides, cholesterol and phospholipids.

Triglycerides are the main form of lipid storage in adipose tissue and lipid transport in the blood. The study of triglyceride levels is necessary to determine the type of hyperlipoproteinemia and assess the risk of developing cardiovascular diseases.

Cholesterol performs the most important functions: it is part of cell membranes, is a precursor of bile acids, steroid hormones and vitamin D, and acts as an antioxidant. About 10% of the Russian population have elevated blood cholesterol levels. This condition is asymptomatic and can lead to serious diseases (atherosclerotic vascular disease, coronary heart disease).

Lipids are insoluble in water, therefore they are transported by blood serum in combination with proteins. Complexes of lipids + protein are called lipoproteins. Proteins involved in lipid transport are called apoproteins.

Several classes are present in the blood serum lipoproteins: chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL).

Each lipoprotein fraction has its own function. synthesized in the liver, carry mainly triglycerides. They play an important role in atherogenesis. Low density lipoproteins (LDL) rich in cholesterol, deliver cholesterol to peripheral tissues. VLDL and LDL levels contribute to the deposition of cholesterol in the vessel wall and are considered atherogenic factors. High density lipoproteins (HDL) participate in the reverse transport of cholesterol from tissues, taking it from overloaded tissue cells and transferring it to the liver, which “utilizes” and removes it from the body. A high level of HDL is considered as an anti-atherogenic factor (protects the body from atherosclerosis).

The role of cholesterol and the risk of developing atherosclerosis depends on which fractions of lipoproteins it is included in. To assess the ratio of atherogenic and antiatherogenic lipoproteins, atherogenic index.

Apolipoproteins are proteins that are located on the surface of lipoproteins.

Apolipoprotein A (ApoA protein) is the main protein component of lipoproteins (HDL), transporting cholesterol from cells of peripheral tissues to the liver.

Apolipoprotein B (ApoB protein) is part of lipoproteins that transport lipids to peripheral tissues.

Measurement of the concentration of apolipoprotein A and apolipoprotein B in the blood serum provides the most accurate and unambiguous determination of the ratio of atherogenic and antiatherogenic properties of lipoproteins, which is estimated as the risk of developing atherosclerotic vascular lesions and coronary heart disease over the next five years.

In research lipid profile includes the following indicators: cholesterol, triglycerides, VLDL, LDL, HDL, atherogenic coefficient, cholesterol / triglyceride ratio, glucose. This profile provides complete information about lipid metabolism, allows you to determine the risks of developing atherosclerotic vascular lesions, coronary heart disease, identify the presence of dyslipoproteinemia and type it, and, if necessary, choose the right lipid-lowering therapy.

Indications

Increasing concentrationcholesterol has diagnostic value in primary familial hyperlipidemias (hereditary forms of the disease); pregnancy, hypothyroidism, nephrotic syndrome, obstructive liver diseases, pancreatic diseases (chronic pancreatitis, malignant neoplasms), diabetes mellitus.

Decreased concentrationcholesterol has diagnostic value in liver diseases (cirrhosis, hepatitis), starvation, sepsis, hyperthyroidism, megaloblastic anemia.

Increasing concentrationtriglycerides has diagnostic value in primary hyperlipidemias (hereditary forms of the disease); obesity, excessive consumption of carbohydrates, alcoholism, diabetes mellitus, hypothyroidism, nephrotic syndrome, chronic renal failure, gout, acute and chronic pancreatitis.

Decreased concentrationtriglycerides has diagnostic value in hypolipoproteinemia, hyperthyroidism, malabsorption syndrome.

Very low density lipoproteins (VLDL) used to diagnose dyslipidemia (IIb, III, IV and V types). High concentrations of VLDL in blood serum indirectly reflect the atherogenic properties of serum.

Increasing concentrationlow density lipoprotein (LDL) has diagnostic value in primary hypercholesterolemia, dyslipoproteinemia (IIa and IIb types); with obesity, obstructive jaundice, nephrotic syndrome, diabetes mellitus, hypothyroidism. Determining the level of LDL is necessary for the appointment of long-term treatment, the purpose of which is to reduce the concentration of lipids.

Increasing concentration has diagnostic value in liver cirrhosis, alcoholism.

Decreased concentrationhigh density lipoprotein (HDL) has diagnostic value in hypertriglyceridemia, atherosclerosis, nephrotic syndrome, diabetes mellitus, acute infections, obesity, smoking.

Level detection apolipoprotein A indicated for early risk assessment of coronary heart disease; identification of patients with a hereditary predisposition to atherosclerosis at a relatively young age; monitoring treatment with lipid-lowering drugs.

Increasing concentrationapolipoprotein A has diagnostic value in diseases of the liver, pregnancy.

Decreased concentrationapolipoprotein A has diagnostic value in nephrotic syndrome, chronic renal failure, triglyceridemia, cholestasis, sepsis.

Diagnostic valueapolipoprotein B- the most accurate indicator of the risk of developing cardiovascular diseases, is also the most adequate indicator of the effectiveness of statin therapy.

Increasing concentrationapolipoprotein B has diagnostic value in dyslipoproteinemias (IIa, IIb, IV and V types), coronary heart disease, diabetes mellitus, hypothyroidism, nephrotic syndrome, liver diseases, Itsenko-Cushing's syndrome, porphyria.

Decreased concentrationapolipoprotein B has diagnostic value in hyperthyroidism, malabsorption syndrome, chronic anemia, inflammatory diseases of the joints, multiple myeloma.

Methodology

The determination is carried out on a biochemical analyzer "Architect 8000".

Preparation

to the study of the lipid profile (cholesterol, triglycerides, HDL-C, LDL-C, Apo-proteins of lipoproteins (Apo A1 and Apo-B)

It is necessary to refrain from physical activity, alcohol, smoking and drugs, changes in diet for at least two weeks before blood sampling.

Blood is taken only on an empty stomach, 12-14 hours after the last meal.

It is advisable to take the morning medication after taking blood (if possible).

The following procedures should not be performed before donating blood: injections, punctures, general body massage, endoscopy, biopsy, ECG, X-ray examination, especially with the introduction of a contrast agent, dialysis.

If, nevertheless, there was a slight physical activity, you need to rest for at least 15 minutes before donating blood.

Lipid testing is not carried out in infectious diseases, since there is a decrease in the level of total cholesterol and HDL-C, regardless of the type of infectious agent, the clinical condition of the patient. The lipid profile should only be checked after the patient has fully recovered.

It is very important that these recommendations are strictly observed, since only in this case reliable results of the blood test will be obtained.

Lipids are chemically diverse substances that have a number of common physical, physicochemical and biological properties. They are characterized by the ability to dissolve in ether, chloroform, other fatty solvents and only slightly (and not always) in water, and also form the main structural component of living cells together with proteins and carbohydrates. The inherent properties of lipids are determined by the characteristic features of the structure of their molecules.

The role of lipids in the body is very diverse. Some of them serve as a form of deposition (triacylglycerols, TG) and transport (free fatty acids - FFA) of substances, during the decay of which a large amount of energy is released, ...
others are the most important structural components of cell membranes (free cholesterol and phospholipids). Lipids are involved in the processes of thermoregulation, protection of vital organs (for example, kidneys) from mechanical influences (injuries), protein loss, in creating elasticity of the skin, protecting them from excessive moisture removal.

Some of the lipids are biologically active substances that have the properties of modulators of hormonal influence (prostaglandins) and vitamins (fatty polyunsaturated acids). Moreover, lipids promote the absorption of fat-soluble vitamins A, D, E, K; act as antioxidants (vitamins A, E), largely regulating the process of free-radical oxidation of physiologically important compounds; determine the permeability of cell membranes in relation to ions and organic compounds.

Lipids serve as precursors for a number of steroids with a pronounced biological effect - bile acids, vitamins of group D, sex hormones, hormones of the adrenal cortex.

The concept of "total lipids" of plasma includes neutral fats (triacylglycerols), their phosphorylated derivatives (phospholipids), free and ester-bound cholesterol, glycolipids, non-esterified (free) fatty acids.

Clinical and diagnostic significance of determining the level of total lipids in blood plasma (serum)

The norm is 4.0-8.0 g / l.

Hyperlipidemia (hyperlipemia) - an increase in the concentration of total plasma lipids as a physiological phenomenon can be observed 1.5 hours after a meal. Alimentary hyperlipemia is more pronounced, the lower the level of lipids in the patient's blood on an empty stomach.

The concentration of lipids in the blood changes in a number of pathological conditions. So, in patients with diabetes, along with hyperglycemia, there is a pronounced hyperlipemia (often up to 10.0-20.0 g / l). With nephrotic syndrome, especially lipoid nephrosis, the content of lipids in the blood can reach even higher figures - 10.0-50.0 g / l.

Hyperlipemia is a constant phenomenon in patients with biliary cirrhosis of the liver and in patients with acute hepatitis (especially in the icteric period). Elevated blood lipids are usually found in individuals suffering from acute or chronic nephritis, especially if the disease is accompanied by edema (due to the accumulation of plasma LDL and VLDL).

The pathophysiological mechanisms that cause shifts in the content of all fractions of total lipids determine, to a greater or lesser extent, a pronounced change in the concentration of its constituent subfractions: cholesterol, total phospholipids and triacylglycerols.

Clinical and diagnostic significance of the study of cholesterol (CS) in serum (plasma) of blood

The study of the level of cholesterol in the serum (plasma) of the blood does not provide accurate diagnostic information about a specific disease, but only reflects the pathology of lipid metabolism in the body.

According to epidemiological studies, the upper level of cholesterol in the blood plasma of practically healthy people aged 20-29 years is 5.17 mmol/l.

In blood plasma, cholesterol is found mainly in the composition of LDL and VLDL, and 60-70% of it is in the form of esters (bound cholesterol), and 30-40% is in the form of free, non-esterified cholesterol. Bound and free cholesterol make up the amount of total cholesterol.

A high risk of developing coronary atherosclerosis in people aged 30-39 and older than 40 years occurs at cholesterol levels exceeding 5.20 and 5.70 mmol / l, respectively.

Hypercholesterolemia is the most proven risk factor for coronary atherosclerosis. This has been confirmed by numerous epidemiological and clinical studies that have established a link between hypercholesterolemia and coronary atherosclerosis, the incidence of coronary artery disease and myocardial infarction.

The highest level of cholesterol is observed in genetic disorders in the metabolism of LP: familial homo- and heterozygous hypercholesterolemia, familial combined hyperlipidemia, polygenic hypercholesterolemia.

In a number of pathological conditions, secondary hypercholesterolemia develops. . It is observed in liver diseases, kidney damage, malignant tumors of the pancreas and prostate, gout, coronary artery disease, acute myocardial infarction, hypertension, endocrine disorders, chronic alcoholism, type I glycogenosis, obesity (in 50-80% of cases).

A decrease in plasma cholesterol levels is observed in patients with malnutrition, with damage to the central nervous system, mental retardation, chronic insufficiency of the cardiovascular system, cachexia, hyperthyroidism, acute infectious diseases, acute pancreatitis, acute purulent-inflammatory processes in soft tissues, febrile conditions, pulmonary tuberculosis, pneumonia, respiratory sarcoidosis, bronchitis, anemia, hemolytic jaundice, acute hepatitis, malignant liver tumors, rheumatism.

The determination of the fractional composition of blood plasma cholesterol and its individual lipoproteins (primarily HDL) has become of great diagnostic importance for judging the functional state of the liver. According to modern ideas, the esterification of free cholesterol to HDL is carried out in blood plasma due to the enzyme lecithin-cholesterol acyltransferase, which is formed in the liver (this is an organ-specific liver enzyme). The activator of this enzyme is one of the main components of HDL - apo - Al, which is constantly synthesized in the liver.

Albumin, also produced by hepatocytes, serves as a nonspecific activator of the plasma cholesterol esterification system. This process primarily reflects the functional state of the liver. If normally the coefficient of cholesterol esterification (i.e. the ratio of the content of ester-bound cholesterol to total) is 0.6-0.8 (or 60-80%), then in acute hepatitis, exacerbation of chronic hepatitis, cirrhosis of the liver, obstructive jaundice, and also chronic alcoholism, it decreases. A sharp decrease in the severity of the process of cholesterol esterification indicates a lack of liver function.

Clinical and diagnostic significance of concentration studies

total phospholipids in serum.

Phospholipids (PL) are a group of lipids containing, in addition to phosphoric acid (as an essential component), an alcohol (usually glycerol), fatty acid residues, and nitrogenous bases. Depending on the nature of the alcohol, PL is subdivided into phosphoglycerides, phosphosphingosines, and phosphoinositides.

The level of total PL (lipid phosphorus) in the blood serum (plasma) is increased in patients with primary and secondary hyperlipoproteinemia types IIa and IIb. This increase is most pronounced in type I glycogenosis, cholestasis, obstructive jaundice, alcoholic and biliary cirrhosis, viral hepatitis (mild course), renal coma, posthemorrhagic anemia, chronic pancreatitis, severe diabetes mellitus, nephrotic syndrome.

For the diagnosis of a number of diseases, it is more informative to study the fractional composition of blood serum phospholipids. For this purpose, thin-layer lipid chromatography methods have been widely used in recent years.

Composition and properties of blood plasma lipoproteins

Almost all plasma lipids are associated with proteins, which gives them good water solubility. These lipid-protein complexes are commonly referred to as lipoproteins.

According to the modern concept, lipoproteins are high-molecular water-soluble particles, which are complexes of proteins (apoproteins) and lipids formed by weak, non-covalent bonds, in which polar lipids (PL, CXC) and proteins (“apo”) make up the surface hydrophilic monomolecular layer surrounding and protecting the internal phase (consisting mainly of ECS, TG) from water.

In other words, LP are peculiar globules, inside of which there is a fat drop, a core (formed mainly by non-polar compounds, mainly triacylglycerols and cholesterol esters), delimited from water by a surface layer of protein, phospholipids and free cholesterol.

The physical features of lipoproteins (their size, molecular weight, density), as well as the manifestations of physicochemical, chemical and biological properties, largely depend, on the one hand, on the ratio between the protein and lipid components of these particles, on the other hand, on the composition of the protein and lipid components, i.e. their nature.

The largest particles, consisting of 98% lipids and a very small (about 2%) proportion of protein, are chylomicrons (XM). They are formed in the cells of the mucous membrane of the small intestine and are a transport form for neutral dietary fats, i.e. exogenous TG.

Table 7.3 Composition and some properties of blood serum lipoproteins

If exogenous TG are transferred into the blood by chylomicrons, then the transport form endogenous TG are VLDL. Their formation is a protective reaction of the body, aimed at preventing fatty infiltration, and subsequently liver dystrophy.

The dimensions of VLDL are, on average, 10 times smaller than the size of XM (individual particles of VLDL are 30-40 times smaller than the particles of XM). They contain 90% of lipids, among which more than half of the content is TG. 10% of total plasma cholesterol is carried by VLDL. Due to the content of a large amount of TG VLDL, an insignificant density is detected (less than 1.0). Determined that LDL and VLDL contain 2/3 (60%) of the total cholesterol plasma, while 1/3 is accounted for by HDL.

HDL- the most dense lipid-protein complexes, since the protein content in them is about 50% of the particle mass. Their lipid component consists half of phospholipids, half of cholesterol, mainly ester-bound. HDL is also constantly formed in the liver and partly in the intestine, as well as in the blood plasma as a result of the “degradation” of VLDL.

If LDL and VLDL deliver cholesterol from the liver to other tissues(peripheral), including vascular wall, That HDL transport cholesterol from cell membranes (primarily the vascular wall) to the liver. In the liver, it goes to the formation of bile acids. In accordance with such participation in cholesterol metabolism, VLDL and themselves LDL are called atherogenic, A HDL– antiatherogenic drugs. Atherogenicity refers to the ability of lipid-protein complexes to introduce (transfer) free cholesterol contained in LP into tissues.

HDL compete for cell membrane receptors with LDL, thereby counteracting the utilization of atherogenic lipoproteins. Since the surface monolayer of HDL contains a large amount of phospholipids, favorable conditions are created at the point of contact of the particle with the outer membrane of the endothelial, smooth muscle, and any other cell for the transfer of excess free cholesterol to HDL.

However, the latter is retained in the surface monolayer of HDL only for a very short time, since it undergoes esterification with the participation of the LCAT enzyme. The formed ECS, being a non-polar substance, moves into the internal lipid phase, freeing vacancies for repeating the act of capturing a new CXC molecule from the cell membrane. From here: the higher the activity of LCAT, the more effective the anti-atherogenic effect of HDL, which are considered as LCAT activators.

If the balance between the influx of lipids (cholesterol) into the vascular wall and their outflow from it is disturbed, conditions can be created for the formation of lipoidosis, the most famous manifestation of which is atherosclerosis.

In accordance with the ABC nomenclature of lipoproteins, primary and secondary lipoproteins are distinguished. Primary LPs are formed by any one apoprotein by chemical nature. They can conditionally be classified as LDL, which contain about 95% of apoprotein-B. All the rest are secondary lipoproteins, which are associated complexes of apoproteins.

Normally, approximately 70% of plasma cholesterol is in the composition of "atherogenic" LDL and VLDL, while about 30% circulates in the composition of "anti-atherogenic" HDL. With this ratio in the vascular wall (and other tissues), the balance of the rates of inflow and outflow of cholesterol is maintained. This determines the numerical value cholesterol coefficient atherogenicity, which, with the indicated lipoprotein distribution of total cholesterol 2,33 (70/30).

According to the results of mass, epidemiological observations, at a concentration of total cholesterol in plasma of 5.2 mmol/l, a zero balance of cholesterol in the vascular wall is maintained. An increase in the level of total cholesterol in the blood plasma of more than 5.2 mmol / l leads to its gradual deposition in the vessels, and at a concentration of 4.16-4.68 mmol / l, a negative balance of cholesterol in the vascular wall is observed. The level of total plasma (serum) cholesterol in excess of 5.2 mmol / l is considered pathological.

Table 7.4 Scale for assessing the likelihood of developing coronary artery disease and other manifestations of atherosclerosis

For the differential diagnosis of coronary artery disease, another indicator is used - cholesterol coefficient of atherogenicity . It can be calculated using the formula: LDL Cholesterol + VLDL Cholesterol / HDL Cholesterol.

More commonly used in clinical practice Klimov coefficient, which is calculated as follows: Total cholesterol - HDL cholesterol / HDL cholesterol. In healthy people, the Klimov coefficient Not exceeds "3", the higher this coefficient, the higher the risk of developing coronary artery disease.

The system "lipid peroxidation - antioxidant defense of the body"

In recent years, interest in the clinical aspects of the study of the process of free radical lipid peroxidation has increased immeasurably. This is largely due to the fact that a defect in this link of metabolism can significantly reduce the body's resistance to the effects of adverse factors of the external and internal environment on it, as well as create prerequisites for the formation, accelerated development and aggravation of the severity of the course of various diseases of vital organs: lungs, heart , liver, kidneys, etc. A characteristic feature of this so-called free radical pathology is membrane damage, which is why it is also called membrane pathology.

The deterioration of the ecological situation noted in recent years, associated with prolonged exposure to ionizing radiation on people, progressive pollution of the air basin with dust particles, exhaust gases and other toxic substances, as well as soil and water with nitrites and nitrates, chemicalization of various industries, smoking, and alcohol abuse have led to to the fact that under the influence of radioactive contamination and foreign substances in large quantities began to form very reactive substances that significantly disrupt the course of metabolic processes. Common to all these substances is the presence of unpaired electrons in their molecules, which makes it possible to classify these intermediates among the so-called free radicals (SR).

Free radicals are particles that differ from ordinary ones in that in the electron layer of one of their atoms in the outer orbital there are not two mutually holding each other electrons that make this orbital filled, but only one.

When the outer orbital of an atom or molecule is filled with two electrons, a particle of a substance acquires a more or less pronounced chemical stability, while if there is only one electron in the orbital, due to its influence - the uncompensated magnetic moment and the high mobility of the electron within the molecule - the chemical activity of the substance increases sharply.

SR can be formed by splitting off a hydrogen atom (ion) from a molecule, as well as by adding (incomplete reduction) or donating (incomplete oxidation) one of the electrons. It follows that free radicals can be either electrically neutral particles or particles that carry a negative or positive charge.

One of the most widespread free radicals in the body is the product of incomplete reduction of the oxygen molecule - superoxide anion radical (O 2 -). It is constantly formed with the participation of special enzyme systems in the cells of many pathogenic bacteria, blood leukocytes, macrophages, alveolocytes, cells of the intestinal mucosa, which have an enzyme system that produces this superoxide oxygen radical anion. Mitochondria make a great contribution to the synthesis of O 2 - as a result of the "draining" of part of the electrons from the mitochondrial chain and transferring them directly to molecular oxygen. This process is significantly activated in conditions of hyperoxia (hyperbaric oxygenation), which explains the toxic effect of oxygen.

Two lipid peroxidation pathways:

1) non-enzymatic, ascorbate dependent, activated by metal ions of variable valence; since in the process of oxidation Fe ++ turns into Fe +++, its continuation requires the reduction (with the participation of ascorbic acid) of ferrous oxide to ferrous;

2) enzymatic, NADP H-dependent, carried out with the participation of NADP H-dependent microsomal dioxygenase, generating O — 2 .

Lipid peroxidation proceeds along the first pathway in all membranes, along the second - only in the endoplasmic reticulum. To date, other special enzymes are also known (cytochrome P-450, lipoxygenases, xanthine oxidases) that form free radicals and activate lipid peroxidation in microsomes. (microsomal oxidation), other cell organelles with the participation of NADP·H, pyrophosphate and ferrous iron as cofactors. With hypoxia-induced decrease in pO 2 in tissues, xanthine dehydrogenase is converted to xanthine oxidase. In parallel with this process, another one is activated - the conversion of ATP into hypoxanthine and xanthine. Xanthine oxidase acts on xanthine to form superoxide anion radicals of oxygen. This process is observed not only during hypoxia, but also during inflammation, accompanied by stimulation of phagocytosis and activation of the hexose monophosphate shunt in leukocytes.

Antioxidant systems

The described process would develop uncontrollably if there were no substances (enzymes and non-enzymes) in the cellular elements of tissues that counteract its course. They became known as antioxidants.

Non-enzymatic free radical oxidation inhibitors are natural antioxidants - alpha-tocopherol, steroid hormones, thyroxine, phospholipids, cholesterol, retinol, ascorbic acid.

Basic natural antioxidant alpha-tocopherol is found not only in plasma, but also in red blood cells. It is believed that the molecules alpha tocopherol, are built into the lipid layer of the erythrocyte membrane (as well as all other cell membranes of the body), protect unsaturated fatty acids of phospholipids from peroxidation. Preservation of the structure of cell membranes largely determines their functional activity.

The most common of the antioxidants is alpha-tocopherol (vitamin E), containing in plasma and in plasma cell membranes, retinol (vitamin A), ascorbic acid, some enzymes like superoxide dismutase (SOD) erythrocytes and other tissues ceruloplasmin(destroying superoxide anion radicals of oxygen in blood plasma), glutathione peroxidase, glutathione reductase, catalase etc., influencing the content of lipid peroxidation products.

With a sufficiently high content of alpha-tocopherol in the body, only a small amount of LPO products are formed, which are involved in the regulation of many physiological processes, including: cell division, ion transport, cell membrane renewal, in the biosynthesis of hormones, prostaglandins, in the implementation of oxidative phosphorylation. A decrease in the content of this antioxidant in tissues (causing a weakening of the body's antioxidant defense) leads to the fact that lipid peroxidation products begin to produce a pathological effect instead of a physiological one.

Pathological conditions, characterized increased formation of free radicals and activation of lipid peroxidation, may be independent, in many respects similar in pathobiochemical and clinical manifestations of the disease ( beriberi E, radiation injury, some chemical poisoning). At the same time, the initiation of free-radical lipid oxidation plays an important role in formation of various somatic diseases associated with damage to internal organs.

LPO products formed in excess cause a violation of not only lipid interactions in biomembranes, but also their protein component - due to binding to amine groups, which leads to a violation of the protein-lipid relationship. As a result, the accessibility of the hydrophobic layer of the membrane to phospholipases and proteolytic enzymes is increased. This enhances the processes of proteolysis and, in particular, the breakdown of lipoprotein proteins (phospholipids).

Free radical oxidation causes a change in elastic fibers, initiates fibroplastic processes and aging collagen. At the same time, the membranes of erythrocyte cells and arterial endothelium are the most vulnerable, since they, having a relatively high content of easily oxidized phospholipids, come into contact with a relatively high concentration of oxygen. Destruction of the elastic layer of the parenchyma of the liver, kidneys, lungs and blood vessels entails fibrosis, including pneumofibrosis(with inflammatory diseases of the lungs), atherosclerosis and calcification.

There is no doubt about the pathogenetic role LPO activation in the formation of disorders in the body during chronic stress.

A close correlation was found between the accumulation of lipid peroxidation products in the tissues of vital organs, plasma and erythrocytes, which makes it possible to use blood to judge the intensity of free radical lipid oxidation in other tissues.

The pathogenetic role of lipid peroxidation in the formation of atherosclerosis and coronary heart disease, diabetes mellitus, malignant neoplasms, hepatitis, cholecystitis, burn disease, pulmonary tuberculosis, bronchitis, and nonspecific pneumonia has been proven.

The establishment of LPO activation in a number of diseases of internal organs was the basis for the use of antioxidants of various nature for therapeutic purposes.

Their use gives a positive effect in chronic coronary heart disease, tuberculosis (also causing the elimination of adverse reactions to antibacterial drugs: streptomycin, etc.), many other diseases, as well as chemotherapy of malignant tumors.

Antioxidants are increasingly being used to prevent the consequences of exposure to certain toxic substances, to alleviate the "spring weakness" syndrome (due to the intensification of lipid peroxidation, as it is believed), to prevent and treat atherosclerosis, and many other diseases.

Apples, wheat germ, wheat flour, potatoes, and beans are relatively high in alpha-tocopherol.

To diagnose pathological conditions and evaluate the effectiveness of the treatment, it is customary to determine the content of primary (diene conjugates), secondary (malonic dialdehyde) and final (Schiff bases) LPO products in plasma and erythrocytes. In some cases, the activity of antioxidant defense enzymes is studied: SOD, ceruloplasmin, glutathione reductase, glutathione peroxidase and catalase. Integral test for assessing LPO is determination of the permeability of erythrocyte membranes or the osmotic stability of erythrocytes.

It should be noted that pathological conditions characterized by increased formation of free radicals and activation of lipid peroxidation can be:

1) an independent disease with a characteristic clinical picture, such as beriberi E, radiation injury, some chemical poisoning;

2) somatic diseases associated with damage to internal organs. These include, first of all: chronic ischemic heart disease, diabetes mellitus, malignant neoplasms, inflammatory lung diseases (tuberculosis, nonspecific inflammatory processes in the lungs), liver disease, cholecystitis, burn disease, gastric ulcer and duodenal ulcer.

It should be borne in mind that the use of a number of well-known drugs (streptomycin, tubazide, etc.) in the course of chemotherapy for pulmonary tuberculosis and other diseases can in itself cause activation of lipid peroxidation, and, consequently, aggravation of the severity of the course of diseases.

Determination of blood lipid profile indicators is necessary for the diagnosis, treatment and prevention of cardiovascular diseases. The most important mechanism for the development of such a pathology is the formation of atherosclerotic plaques on the inner wall of the vessels. Plaques are accumulations of fat-containing compounds (cholesterol and triglycerides) and fibrin. The higher the concentration of lipids in the blood, the more likely the appearance of atherosclerosis. Therefore, it is necessary to systematically take a blood test for lipids (lipidogram), this will help to identify deviations of fat metabolism from the norm in a timely manner.

Lipidogram - a study that determines the level of lipids of various fractions

Atherosclerosis is dangerous with a high probability of developing complications - stroke, myocardial infarction, gangrene of the lower extremities. These diseases often end in disability of the patient, and in some cases, death.

Role of lipids

Lipid functions:

• Structural. Glycolipids, phospholipids, cholesterol are the most important components of cell membranes.
• Thermal insulation and protective. Excess fats are deposited in the subcutaneous fat, reducing heat loss and protecting internal organs. If necessary, the lipid reserve is used by the body for energy and simple compounds.
• Regulatory. Cholesterol is necessary for the synthesis of steroid hormones of the adrenal glands, sex hormones, vitamin D, bile acids, is part of the myelin sheaths of the brain, and is needed for the normal functioning of serotonin receptors.

Lipidogram

A lipidogram can be prescribed by a doctor both if an existing pathology is suspected, or for preventive purposes, for example, during a medical examination. It includes several indicators that allow you to fully assess the state of fat metabolism in the body.

Lipidogram indicators:

• Total cholesterol (OH). This is the most important indicator of the lipid spectrum of the blood, it includes free cholesterol, as well as cholesterol contained in lipoproteins and associated with fatty acids. A significant part of cholesterol is synthesized by the liver, intestines, gonads, only 1/5 of the OH comes from food. With normally functioning mechanisms of lipid metabolism, a small deficiency or excess of cholesterol from food is compensated by an increase or decrease in its synthesis in the body. Therefore, hypercholesterolemia is most often caused not by excessive intake of cholesterol from foods, but by a failure of the fat metabolism process.
• High density lipoproteins (HDL). This indicator has an inverse relationship with the likelihood of developing atherosclerosis - an elevated HDL level is considered an anti-atherogenic factor. HDL transport cholesterol to the liver, where it is utilized. Women have higher HDL levels than men.
• Low density lipoproteins (LDL). LDL carries cholesterol from the liver to the tissues, otherwise known as "bad" cholesterol. This is due to the fact that LDL can form atherosclerotic plaques that narrow the lumen of blood vessels.

This is what an LDL particle looks like

• Very low density lipoproteins (VLDL). The main function of this group of particles, heterogeneous in size and composition, is the transport of triglycerides from the liver to tissues. A high concentration of VLDL in the blood leads to clouding of the serum (chylosis), and the possibility of atherosclerotic plaques also increases, especially in patients with diabetes mellitus and kidney pathologies.
• Triglycerides (TG). Like cholesterol, triglycerides are transported through the bloodstream as part of lipoproteins. Therefore, an increase in the concentration of TG in the blood is always accompanied by an increase in cholesterol levels. Triglycerides are considered the main source of energy for cells.
• Atherogenic coefficient. It allows you to assess the risk of developing vascular pathology and is a kind of outcome of the lipid profile. To determine the indicator, you need to know the value of OH and HDL.

Atherogenic coefficient \u003d (OH - HDL) / HDL

Optimal blood lipid profile values

It should be borne in mind that the value of the measured indicators may vary depending on the units of measurement, the methodology for conducting the analysis. Normal values ​​also vary depending on the age of the patient, the above figures are averaged for persons 20-30 years old. The norm of cholesterol and LDL in men after 30 years tends to increase. In women, the indicators increase sharply with the onset of menopause, this is due to the cessation of the anti-atherogenic activity of the ovaries. Deciphering the lipidogram must be carried out by a specialist, taking into account the individual characteristics of a person.

The study of blood lipid levels may be prescribed by a doctor to diagnose dyslipidemia, assess the likelihood of developing atherosclerosis, in some chronic diseases (diabetes mellitus, kidney and liver diseases, thyroid gland), and also as a screening study for early detection of individuals with abnormal lipid profiles from the norm .

The doctor gives the patient a referral for a lipidogram

Study preparation

Lipidogram values ​​can fluctuate not only depending on the gender and age of the subject, but also on the impact on the body of various external and internal factors. To minimize the likelihood of an unreliable result, you must adhere to several rules:

1. Donate blood should be strictly in the morning on an empty stomach, in the evening of the previous day, a light dietary dinner is recommended.
2. Do not smoke or drink alcohol on the eve of the study.
3. 2-3 days before donating blood, avoid stressful situations and intense physical exertion.
4. Refuse to use all medications and dietary supplements, except for vital ones.

Methodology

There are several methods for laboratory assessment of the lipid profile. In medical laboratories, analysis can be carried out manually or using automatic analyzers. The advantage of an automated measurement system is the minimum risk of erroneous results, the speed of obtaining an analysis, and the high accuracy of the study.

The analysis requires the patient's venous blood serum. Blood is taken into a vacuum tube using a syringe or vacutainer. To avoid the formation of a clot, the blood tube should be inverted several times, then centrifuged to obtain serum. The sample can be stored in the refrigerator for 5 days.

Taking blood for lipid profile

Currently, blood lipids can be measured without leaving home. To do this, you need to purchase a portable biochemical analyzer that allows you to assess the level of total cholesterol in the blood or several indicators at once in a matter of minutes. For research, you need a drop of capillary blood, it is applied to the test strip. The test strip is impregnated with a special composition, for each indicator it has its own. The results are read automatically after inserting the strip into the device. Due to the small size of the analyzer, the ability to operate on batteries, it is convenient to use it at home and take it with you on a trip. Therefore, persons with a predisposition to cardiovascular diseases are advised to have it at home.

Interpretation of results

The most ideal result of the analysis for the patient will be a laboratory conclusion that there are no deviations from the norm. In this case, a person can not be afraid for the state of his circulatory system - the risk of atherosclerosis is practically absent.

Unfortunately, this is not always the case. Sometimes the doctor, after reviewing the laboratory data, makes a conclusion about the presence of hypercholesterolemia. What it is? Hypercholesterolemia - an increase in the concentration of total cholesterol in the blood above normal values, while there is a high risk of developing atherosclerosis and related diseases. This condition may be due to a number of reasons:

• Heredity. Science knows cases of familial hypercholesterolemia (FH), in such a situation, a defective gene responsible for lipid metabolism is inherited. In patients, a constantly elevated level of TC and LDL is observed, the disease is especially severe in the homozygous form of FH. In such patients, early onset of coronary artery disease (at the age of 5-10 years) is noted, in the absence of proper treatment, the prognosis is unfavorable and in most cases ends in death before reaching 30 years of age.
• Chronic diseases. Elevated cholesterol levels are observed in diabetes mellitus, hypothyroidism, kidney and liver pathology, due to lipid metabolism disorders due to these diseases.

For patients with diabetes, it is important to constantly monitor cholesterol levels.

• Wrong nutrition. Prolonged abuse of fast food, fatty, salty foods leads to obesity, while, as a rule, there is a deviation in lipid levels from the norm.
• Bad habits. Alcoholism and smoking lead to failures in the mechanism of fat metabolism, as a result of which the lipid profile increases.

With hypercholesterolemia, it is necessary to follow a diet with a restriction of fat and salt, but in no case should you completely refuse all foods rich in cholesterol. Only mayonnaise, fast food and all foods containing trans fats should be excluded from the diet. But eggs, cheese, meat, sour cream must be present on the table, you just need to choose products with a lower percentage of fat. Also in the diet it is important to have greens, vegetables, cereals, nuts, seafood. The vitamins and minerals contained in them perfectly help to stabilize lipid metabolism.

An important condition for the normalization of cholesterol is also the rejection of bad habits. Good for the body and constant physical activity.

In the event that a healthy lifestyle in combination with a diet has not led to a decrease in cholesterol, it is necessary to prescribe an appropriate drug treatment.

Drug treatment of hypercholesterolemia includes the appointment of statins

Sometimes specialists are faced with a decrease in cholesterol levels - hypocholesterolemia. Most often, this condition is due to insufficient intake of cholesterol from food. Fat deficiency is especially dangerous for children, in such a situation there will be a lag in physical and mental development, cholesterol is vital for a growing body. In adults, hypocholesteremia leads to a violation of the emotional state due to malfunctions of the nervous system, problems with reproductive function, decreased immunity, etc.

A change in the blood lipid profile inevitably affects the work of the whole organism as a whole, therefore it is important to systematically monitor the indicators of fat metabolism for timely treatment and prevention.