Bile acids in the blood. Drugs that affect bile acid levels

bile acids I Bile acids (synonym: cholic acids, cholic acids, cholenic acids)

organic acids that are part of bile and are the end products of cholesterol metabolism; play important role in the processes of digestion and absorption of fats; contribute to the growth and functioning of normal intestinal microflora.

Bile acids are derivatives of C 23 H 39 COOH cholanic acid, in the molecule of which hydroxyl groups are attached to the ring structure. The main fatty acids found in human bile (Bile) are (3α, 7α, 12α-trioxy-5β-cholanic acid), (. 3α, 7α-dioxy-5β-cholanic acid) and (3α, 12α-dioxy -5β-cholanic acid). In much smaller amounts in bile, stereoisomers of holena and deoxycholic acids were found - allocholic, ursodeoxycholic and lithocholic (3α-manooxy-5β-cholanic) acids. Cholic and chenodeoxycholic acids - the so-called primary fatty acids - are formed in the liver during the oxidation of Cholesterol a , and deoxycholic and lithocholic acids are formed from primary fatty acids in the intestine under the influence of enzymes of microorganisms of the intestinal microflora. Quantity ratio cholic, chenodeoxycholic and deoxycholic acids and bile is normally 1:1:0.6.

In gallbladder bile. to. are present mainly in the form of paired compounds - conjugates. As a result of conjugation of fatty acids with the amino acid glycine, glycocholic or glycochenodeoxycholic acids are formed. When conjugated Zh. to. with taurine (2-aminoethane-sulfonic acid C 2 H 7 O 3 N 5), a product of the degradation of cysteine, taurocholic or taurodeoxycholic acids are formed. The conjugation of Zh. to. includes the stages of formation - esters of Zh. to. and the connection of the molecule of Zh. to. with glycine or taurine through an amide bond with the participation of the lysosomal enzyme acyltransferase. The ratio of glycine and taurine conjugates of fatty acids in bile, which averages 3:1, may vary depending on the composition of the food and the hormonal status of the body. The relative content of glycine conjugates of fatty acids in bile increases with the predominance of carbohydrates in food, with diseases accompanied by protein deficiency, reduced function thyroid gland, and the content of taurine conjugates increases with a high-protein diet and under the influence of cortico steroid hormones.

In hepatic bile, fatty acids are found in the form of bile salts (cholates, or choleates) of potassium and sodium, which explains alkaline reaction hepatic bile. In the intestines, salts of fatty acids provide emulsification of fat and stabilization of the resulting fat emulsion, and also activate pancreatic lipase, shifting the optimum of its activity to the pH range characteristic of the contents of the duodenum.

One of the main functions of fatty acids is the transfer of lipids in the aquatic environment, which is provided due to the detergent properties of fatty acids (see Detergents) , those. them to form a micellar solution of lipids in an aqueous medium. In the liver, with the participation of Zh. to., micelles are formed, in the form of which secreted by the liver are transferred to in a homogeneous solution, i.e. in bile. Due to the detergent properties of fatty acids, stable micelles are formed in the intestines, containing products of the breakdown of fats by lipase, phospholipids, fat-soluble and ensuring the transfer of these components to the suction surface of the intestinal epithelium. In the intestines (mainly in ileum) Zh. to. are absorbed into, with blood they return again to and are again secreted as part of bile (the so-called portal-biliary circulation of Zh. to.), therefore, 85-90% of the total amount of bile acids contained in bile are Zh. to . absorbed in the intestines. Portal-biliary circulation Zh. to. contributes to the fact that the conjugates Zh. to. are easily absorbed in the intestine, tk. they are water soluble. The total number of fatty acids involved in metabolism in humans is 2.8-3.5 G, and the number of revolutions of the F. to. per day is 5-6. In the intestines, 10-15% of the total amount of bile acids undergoes cleavage under the action of enzymes of microorganisms of the intestinal microflora, and degradation products of the fatty acids are excreted with feces. F. to. in the composition of bile and the transformation of F. to. in the intestine play an important role in digestion (Digestion) and the exchange of Cholesterol a .

Normally, in the urine of a person, Zh. to. are not found. On early stages obstructive jaundice and acute pancreatitis small amounts of fatty acids appear in the urine. In the blood, the content and composition of fatty acids changes with diseases of the liver and gallbladder, which makes it possible to use these data in diagnostic purposes. The accumulation of gallbladder in the blood is noted in lesions of the liver parenchyma and obstruction of the outflow of bile. An increase in the content of fatty acids in the blood has a damaging effect on liver cells, causes bradycardia and arterial hypotension, erythrocytes, violation of blood coagulation processes and a decrease in ESR. With an increase in the concentration of Zh. to. in the blood, the appearance of skin itching is characteristic.

With cholecystitis, the content of fatty acids in gallbladder bile is significantly reduced due to a decrease in their formation in the liver and increased absorption of fatty acids in the mucous membrane of the gallbladder.

Zh. to. have a strong choleretic action, which leads to their inclusion in choleretic agents and also stimulate intestinal motility. Their bacteriostatic and anti-inflammatory action explains positive effect at topical application bile for the treatment of arthritis. By production of preparations of steroid hormones Zh. to. use as an initial product.

II Bile acids (acida cholica)

organic acids that are part of bile and are hydroxylated derivatives of cholanic acid; play an important role in the digestion and absorption of lipids, are the end product of cholesterol metabolism.

1. Small medical encyclopedia. - M.: Medical Encyclopedia. 1991-96 2. First health care. - M.: Great Russian Encyclopedia. 1994 3. encyclopedic Dictionary medical terms. - M.: Soviet Encyclopedia. - 1982-1984.

See what "Bile acids" are in other dictionaries:

Bile acids (synonyms: bile acids, cholic acids, cholic acids, cholenic acids) are monocarboxylic hydroxy acids from the class of steroids. Bile acids are derivatives of cholanic acid C23H39COOH, characterized in that to ... Wikipedia

bile acids- View fatty acids, secreted by the liver, providing emulsification of fats Biotechnology topics EN bile acid … Technical Translator's Handbook

Steroid monocarboxylic acids, derivatives of cholanic acid, formed in the liver of humans and animals and excreted with bile in duodenum. In a liver Zh. to. are formed mainly from Cholesterol. J. to., ... ...

BILE ACIDS- bile acids, a group of steroid acids (derivatives of cholanic acid), which are part of bile, are formed in the liver cells. Mammalian fatty acids include cholic, deoxycholic, chenodeoxycholic, and lithocholic acids, which are in the bile ... ...

- (synonyms: bile acids, cholic acids, cholic acids, cholenic acids) monocarboxylic hydroxy acids from the class of steroids. Bile acids are derivatives of cholanic acid C23H39COOH, characterized in that to its ring ... ... Wikipedia

Bile, bile (lat. bilis, other Greek. χολή) yellow, brown or greenish, bitter in taste, having a specific smell, secreted by the liver and accumulated in the gallbladder liquid ... Wikipedia

- (from other Greek ἀντι against, lat. acidus sour) drugs intended for the treatment of acid-dependent diseases of the gastrointestinal tract by neutralizing hydrochloric acid, which is part of ... ... Wikipedia

Various antacids Antacids (from Greek ἀντἰ against, Latin acidus sour) drugs intended for the treatment of acid-related diseases of the gastrointestinal tract by neutralizing the hydrochloric acid included ... Wikipedia

FAT METABOLISM- fat metabolism, a set of processes of transformation of neutral fats (triglycerides) in the body of humans and animals. J. o. consists of the following stages: the breakdown of fats that have entered the body with food and their absorption in the gastrointestinal tract; … Veterinary Encyclopedic Dictionary

A secret continuously produced by the glandular cells of the liver of vertebrates and humans. The liver of an adult person secretes up to 1.2 liters per day; in some diseases, there may be an increase or decrease in the formation of Zh. ... ... Great Soviet Encyclopedia

Bile acids- monocarboxylic hydroxy acids from the class of steroids, derivatives of cholanic acid C 23 H 39 COOH. Synonyms: bile acids, cholic acids, cholic acids or cholenic acids.

The main types of bile acids circulating in the human body are the so-called primary bile acids , which are primarily produced by the liver, cholic and chenodeoxycholic, as well as secondary formed from primary bile acids in the colon under the action of intestinal microflora: deoxycholic, lithocholic, allocholic and ursodeoxycholic. Of the secondary acids in the enterohepatic circulation, only deoxycholic acid, which is absorbed into the blood and then secreted by the liver as part of bile, participates in a noticeable amount. In the bile of the human gallbladder, bile acids are in the form of conjugates of cholic, deoxycholic and chenodeoxycholic acids with glycine and taurine: glycocholic, glycodeoxycholic, glycochenodeoxycholic, taurocholic, taurodeoxycholic and taurochenodeoxycholic acids - compounds also called paired acids. Different mammals have different sets of bile acids.

Bile acids in drugs

Bile acids, chenodeoxycholic and ursodeoxycholic are the basis of drugs used in the treatment of diseases of the gallbladder. IN Lately ursodeoxycholic acid recognized effective tool in the treatment of bile reflux.

In April 2015, the FDA approved the use of Kybella for non-surgical treatment double chins, active substance which is synthetic deoxycholic acid.

At the end of May 2016, the FDA approved the use of obeticholic acid Ocaliva for the treatment of primary biliary cholangitis in adults.

Metabolism of bile acids with the participation of intestinal microflora

Bile acids and diseases of the esophagus

In addition to hydrochloric acid and pepsin, secreted in the stomach, the components of the duodenal contents can have a damaging effect on the mucous membrane of the esophagus when it enters it: bile acids, lysolecithin and trypsin.

Of these, the role of bile acids, which, apparently, plays a major role in the pathogenesis of damage to the esophagus in duodenogastric esophageal reflux, is the most well studied. It has been established that conjugated bile acids (primarily taurine conjugates) and lysolecithin have a more pronounced damaging effect on the esophageal mucosa at acidic pH, which determines their synergism with hydrochloric acid in the pathogenesis of esophagitis. Unconjugated bile acids and trypsin are more toxic at neutral and slightly alkaline pH, i.e., their damaging effect in the presence of duodenogastroesophageal reflux increases against the background of drug suppression of acid reflux. The toxicity of unconjugated bile acids is mainly due to their ionized forms, which more easily penetrate the mucosa of the esophagus. These data may explain the lack of an adequate clinical response to monotherapy with antisecretory drugs in 15-20% of patients. Moreover, long-term maintenance of esophageal pH close to neutral values can act as a pathogenetic factor in metaplasia and epithelial dysplasia (Bueverov A.O., Lapina T.L.).

In the treatment of esophagitis caused by refluxes in which bile is present, it is recommended, in addition to inhibitors proton pump concurrently prescribe ursodeoxycholic acid preparations. Their use is justified by the fact that under its influence the bile acids contained in the refluxate pass into a water-soluble form, which irritates the mucous membrane of the stomach and esophagus to a lesser extent. Ursodeoxycholic acid has the ability to change the pool of bile acids from toxic to non-toxic. During treatment with ursodeoxycholic acid, in most cases, symptoms such as bitter belching, abdominal discomfort, and vomiting of bile disappear or become less intense. Recent studies have shown that with bile reflux, the dose of 500 mg per day should be considered optimal, dividing it into 2 doses. The duration of the course of treatment is at least 2 months (Chernyavsky V.V.).

Over the past few decades, many new information about bile and its acids. In this regard, it became necessary to revise and expand ideas about their significance for the life of the human body.

The role of bile acids. General information

The rapid development and improvement of research methods has made it possible to study bile acids in more detail. For example, now there is a clearer understanding of metabolism, their interaction with proteins, lipids, pigments and their content in tissues and fluids. Information has been confirmed indicating that bile acids are of great importance not only for normal functioning gastrointestinal tract. These compounds are involved in many processes in the body. It is also important that, thanks to the use of the latest research methods, it was possible to most accurately determine how bile acids behave in the blood, as well as how they affect respiratory system. Among other things, the compounds affect some parts of the central nervous system. Their importance in intracellular and external membrane processes has been proven. This is due to the fact that bile acids act as surfactants in internal environment organism.

Historical facts

This type chemical compounds discovered by the scientist Strecker in the middle of the 19th century. He managed to find out that bile has two. The first of them contains sulfur. The second also contains this substance, but has a completely different formula. In the process of splitting these chemical compounds, cholic acid is formed. As a result of the transformation of the first compound mentioned above, glycerol is formed. At the same time, another bile acid forms a completely different substance. It's called taurine. As a result, the original two compounds were given names with the same names as the produced substances. This is how tauro- and glycocholic acid appeared, respectively. This discovery of the scientist gave a new impetus to the study of this class of chemical compounds.

Bile acid sequestrants

These substances are a group of drugs that have a hypolipidemic effect on the human body. IN last years they have been actively used to lower blood cholesterol levels. This has significantly reduced the risk of various cardiovascular pathologies And coronary disease. On this moment V modern medicine widely used by another group more effective drugs. These are statins. They are used much more often due to the smaller number side effects. At the present time, bile acid sequestrants are used less and less. Sometimes they are used exclusively in the framework of complex and auxiliary treatment.

Detailed information

The steroid class includes monocarbaic hydroxy acids. They are active and poorly soluble in water. These acids result from the processing of cholesterol by the liver. In mammals, they consist of 24 carbon atoms. The composition of the dominant bile compounds in different types animals is different. These types form taucholic and glycolic acids in the body. Chenodeoxycholic and cholic compounds belong to the class of primary compounds. How are they formed? In this process, liver biochemistry matters. Primary compounds arise from the synthesis of cholesterol. Next, the conjugation process takes place together with taurine or glycine. These types of acids are then secreted into the bile. Lithocholic and deoxycholic substances are part of the secondary compounds. They are formed in the large intestine from primary acids under the influence of local bacteria. The rate of absorption of deoxycholic compounds is much higher than that of lithocholic compounds. Other secondary bile acids occur in very small amounts. For example, ursodeoxycholic acid is one of them. If chronic cholestasis occurs, then these compounds are present in huge number. The normal ratio of these substances is 3:1. While with cholestasis, the content of bile acids is considerably exceeded. Micelles are aggregates of their molecules. They are formed only when the concentration of these compounds in aqueous solution exceeds the limit. This is due to the fact that bile acids are surfactants.

Features of cholesterol

This substance is poorly soluble in water. The rate of solubility of cholesterol in bile depends on the ratio of lipid concentration, as well as the molar concentration of lecithin and acids. Mixed micelles arise only when the normal proportion of all these elements is maintained. They contain cholesterol. The precipitation of its crystals is carried out under the condition of violation of this ratio. acids are not limited to removing cholesterol from the body. They promote the absorption of fats in the intestines. Micelles are also formed during this process.

Connection traffic

One of the main conditions for the formation of bile is the active movement of acids. These compounds play an important role in the transport of electrolytes and water in the small and large intestines. They are solid powders. Their melting point is quite high. They have a bitter taste. Bile acids are poorly soluble in water, while alkaline and alcohol solutions- Fine. These compounds are derivatives of cholanic acid. All such acids occur exclusively in cholesterol hepatocytes.

Influence

The most important among all acidic compounds are salts. This is due to a number of properties of these products. For example, they are more polar than salts of free bile acids, have small size limiting concentration of micellar formation and are secreted faster. The liver is sole body capable of converting cholesterol into special cholanic acids. This is due to the fact that the enzymes that take part in conjugation are contained in hepatocytes. The change in their activity is directly dependent on the composition and rate of fluctuations of the bile acids of the liver. The synthesis process is regulated by a mechanism. This means that the intensity this phenomenon is in relation to the current of secondary bile acids in the liver. The rate of their synthesis in the human body is quite low - from two hundred to three hundred milligrams per day.

Main goals

Bile acids have a wide range of uses. IN human body they mainly carry out the synthesis of cholesterol and affect the absorption of fats from the intestines. In addition, the compounds are involved in the regulation of bile secretion and bile formation. These substances also have a strong influence on the process of digestion and absorption of lipids. Their compounds are collected in the small intestine. The process occurs under the influence of monoglycerides and free fatty acids, which are on the surface of fatty deposits. In this case, a thin film is formed, which prevents the connection of small drops of fat into larger ones. Due to this, a strong decrease occurs. This leads to the formation of micellar solutions. They, in turn, facilitate the action of pancreatic lipase. With the help of a fatty reaction, it breaks them down into glycerol, which is then absorbed by the intestinal wall. Bile acids combine with fatty acids that do not dissolve in water and form choleic acids. These compounds are easily broken down and quickly absorbed by the villi of the upper part. small intestine. Choleic acids are converted into micelles. Then they are absorbed into the cells, while easily overcoming their membranes.

Information was received from the most latest research in this area. They prove that the relationship between fatty and bile acids in the cell breaks down. The first ones are final result lipid absorption. The latter - through the portal vein penetrate the liver and blood.

Bile acids are products of cholesterol metabolism. This indicator may indicate the presence of liver disease. Main indications for use: viral hepatitis, alcohol and drug lesion liver, liver tumors, cirrhosis, cholestasis (bile stasis). Bile acids - facilitate the digestion of fats. They are highly effective detergents. After synthesis in the liver, they are concentrated in gallbladder, making up the main component of bile.

Bile acids are substances of a steroid nature. They are synthesized in the liver from cholesterol, then they are excreted in the bile, concentrating several times, and enter the intestine. About 90% of the bile acids are reabsorbed from the intestine and enter the intrahepatic circulation, and are again excreted in the bile. Human bile mainly contains cholic, deoxycholic and chenodeoxycholic acids. Bile also contains small amounts of lithocholic, allocholic and urodeoxycholic acids - stereoisomers of cholic and chenodeoxycholic acids. Most bile acids are bound (conjugated) to glycine or taurine. Bile acids are present in bile in a conjugated form, i.e. in the form of glycocholic, glycodeoxycholic, glycochenodeoxycholic (about 2/3 - 4/5 of all bile acids) or taurocholic, taurodeoxycholic and taurochenodeoxycholic (about 1/5 - 1/3 of all bile acids) acids. The most powerful emulsifying effect on fats is exerted by bile salts that enter the duodenum in the form of sodium salts. Bile salts dramatically reduce the surface tension on the fat/water surface, so that they not only facilitate the emulsification of fats, but also stabilize the emulsion that has already formed. The essence of emulsification is that the interaction of fats and bile acids creates big square contact of fat with the aqueous phase, where the enzymes are located, thus a better breakdown of fats occurs. It should be explained to the patient that the study will assess the condition of the liver. You should warn him that for the study it is necessary to take a blood sample, and inform who and when will take blood from a vein. The patient is warned about possible unpleasant sensations during the imposition of a tourniquet on the arm and puncture of the vein. Fasting is required for 12 hours prior to sampling. The attending physician and the laboratory assistant should be aware of the patient taking drugs that may affect the result of the study. If necessary, these drugs are canceled. After puncture, the veins draw blood into an empty tube or with a gel. The puncture site is pressed down with a cotton ball until the bleeding stops. When a hematoma forms at the puncture site, warm compresses are prescribed. Hemolysis of a blood sample. Cyclosporine. Isoniazid. Methotrexate. Rifampin. Fusidic acid. cholestyramine. Estimate functional state liver. Viral hepatitis. Alcohol defeat liver. Cirrhosis. cholestasis. primary hepatoma. Drug-induced damage to the liver. Cystofibrosis. neonatal hepatitis syndrome. Atresia biliary tract. Cystic fibrosis. Acute cholecystitis.

Bile acids are products of cholesterol metabolism. This indicator may indicate the presence of liver disease. The main indications for use: viral hepatitis, alcoholic and drug damage to the liver, liver tumors, cirrhosis, cholestasis (bile stasis).

Bile acids - facilitate the digestion of fats. They are highly effective detergents. After synthesis in the liver, they are concentrated in the gallbladder, constituting the main component of bile.

Bile acids are present in bile in a conjugated form, i.e. in the form of glycocholic, glycodeoxycholic, glycochenodeoxycholic (about 2/3 - 4/5 of all bile acids) or taurocholic, taurodeoxycholic and taurochenodeoxycholic (about 1/5 - 1/3 of all bile acids) acids. The most powerful emulsifying effect on fats is exerted by bile salts that enter the duodenum in the form of sodium salts. Bile salts dramatically reduce the surface tension on the fat/water surface, so that they not only facilitate the emulsification of fats, but also stabilize the emulsion that has already formed. The essence of emulsification lies in the fact that the interaction of fats and bile acids creates a large area of contact between the fat and the aqueous phase, where the enzymes are located, thus there is a better breakdown of fats.

Bile acids, which are important components bile, synthesized directly in the liver from cholesterol. During meals, the bile that accumulates in the gallbladder is released into the intestines. In the process of digestion, it accelerates the breakdown and absorption of fats, and also helps to preserve healthy microflora. Subsequently, 90% of the bile acids enter the bloodstream, from where they are again taken by the liver.

A blood test that measures the amount of bile acids is important way diagnostics of development various diseases. The obtained data allow to correctly establish the diagnosis and prescribe the correct course of treatment. The following main organic acids that make up bile are distinguished:

Holeva - 38%.
Chenodeoxycholic - 34%.
Deoxycholic - 28%.
Lithocholium - 2%.

What is this analysis

To test the blood for the content of these substances, a unified enzymatic-colorimetric method is used. It is noteworthy that normative indicators at healthy people even after meals change slightly.

Therefore, any deviation from the norm indicates pathologies of the liver and a violation of the outflow of bile. The study does not require a lot of time. Test results can be obtained within an hour after blood sampling.

When is an analysis ordered?

The biochemical analysis may be prescribed by a doctor if there is any suspicion of a malfunction in the functions of the liver. This is due to the fact that the amount of bile acids in the blood increases even with slightly pronounced pathologies. So, the level of these substances always increases with cholestasis, which is observed against the background of a variety of liver diseases.

In order to assess the effectiveness of the prescribed therapy, the study is prescribed in the treatment of diseases in the field of gastroenterology and hepatology. Particularly in people suffering from chronic hepatitis C, decline earlier high performance is the determining factor for a positive prognosis.

The amount of bile acids in blood plasma is also an important marker in obstetrics, since this method can be used to diagnose intrahepatic cholestasis in pregnant women. The study is indicated in the presence of the following obvious symptoms:

Enlargement of the liver.
The occurrence of dryness skin and itching.
When unexplained loss weight.
Frequent stools and skin rashes.

How to prepare for the analysis

A sample is being taken for research. venous blood. To obtain reliable results analysis before donating blood, a person must refuse to eat for at least 9-10 hours.

During the same period, it is forbidden to use alcoholic drinks and sweet juices. It is also important that you do not smoke and remain calm for several hours before blood sampling. Optimal time for the analysis - from 7.30 to 11.30.

Permissible analysis standards

Normal values are in the range of 1.25-3.41 mcg/dL (2.5-6.8 mmol/L). When the bile acids in the blood correspond to them, this is evidence of optimal cholesterol metabolism. Upon confirmation normal indicators In the course of the study, the following diseases can be excluded:

Subhepatic jaundice.
Alcohol intoxication.
Hepatitis.
Cystic fibrosis.
Acute cholecystitis.
Congenital pathologies of the bile ducts.

Deviation of results from the norm

An increase in the level of bile acids clearly indicates impaired liver function, which is often accompanied by other symptoms, such as:

Itching of the skin.
Slow heart rate.
Decreased blood pressure.

In addition, along with an increase in the amount of bile acids, other blood parameters also change, namely:

The level of hemoglobin decreases.
Decreased ESR.
Blood clotting is impaired.
There is a failure in the hemostasis system.

A significant increase in the amount of bile acids is observed with the development of such diseases:

mechanical jaundice.
Cirrhosis of the liver.
Alcohol intoxication.
Viral hepatitis;

The amount of bile acids always increases with cholestasis. This condition is associated with a violation of the outflow of bile due to blockage of the ducts. I can provoke cholestasis not only serious illness, but also different medical preparations which are used to treat a variety of diseases.

During pregnancy slight increase the amount of bile acids is considered natural due to changes hormonal background and other physiological changes in the body. But exceeding the norm by more than 4 times indicates the development of cholestasis in the expectant mother.

The amount of bile acids decreases with cholecystitis. This is due to the fact that during inflammation of the walls of the gallbladder, these substances are synthesized in the liver in a smaller amount. Another reason for the decrease in bile acids can be long-term use medications, which were prescribed to improve cholesterol metabolism.

A blood test for the amount of bile acids is always used in combination with other diagnostic methods. To correct physiological deviations, it is necessary to revise the diet. It is also important to maintain sufficient physical activity to prevent excess weight gain.