Biochemistry of blood: increased alanine aminotransferase
Mar 07, 2018
Investigation of the activity of a number of biological molecules has long been a standard for the diagnosis of a number of pathologies. For example, an increase in alanine aminotransferase serves as a marker for the pathologies of some internal organs.
Brief description of alanine aminotransferase
Alanine aminotransferase( abbreviated as ALAT) is an enzyme involved in the metabolism of most amino acids. Not only those molecules that come from outside. The enzyme can take an active part in the transformation of the amino acid residues of its own protein molecules.
The features of the alanine aminotransferase function, at one time, made it possible to classify it as a type of transferase - a carrier of functional groups from one molecule to another. Therefore, initially it was considered: ALT is located in the liver. Then it was believed that this body is the only one where most of the metabolic processes take place. But a few decades ago, evidence was found for the presence of aminotransferase in the cells of many organs. By the degree and decrease of its concentration, the following series can be set.
- Liver. The concentration of aminotransferase here is several times greater than in other organs.
- The lungs and other organs have approximately the same number of enzymes.
The main purpose of aminotransferase is the transfer of amine groups between amino acids and ketones. And since these reactions occur intracellularly and do not imply the destruction of carrier enzymes, the alanine aminotransferase rate does not exceed 0.1 millimol per milliliter of blood. In international units, this figure is no more than 40 units. But the norm in children depends on age. This mainly applies to the first year of life.
At birth, the aminotransferase is slightly above 25 units. In the first 2 days it rises to 50 and for the first half of the year reaches 60 units. Then comes its gradual decline. By 6-7 years, enzymes become no more than 29 units. These norms last up to 12-14 years. And only by the age of 18-20 alanine aminotransferase takes the usual norms of an adult. The same indicators should be with
Reasons for increasing the enzyme
Such relatively low rates are associated with two factors.
- The enzyme enters the bloodstream only when the cells are destroyed. And the rate of their lysis in the liver, myocardium and kidneys is very low.
- Even in the presence of aminotransferase, the biochemical analysis of blood determines only the active fractions of the enzyme. And as you know - alanine aminotransferase has the greatest functional activity.
From this follows a simple explanation of the importance of the enzyme for the laboratory diagnosis of a number of pathological processes. The larger the number, the more cells were destroyed. Therefore, the causes of increased alanine aminotransferase are directly related to the liver, as the organ with the most active enzymes.
- Hepatitis viral etiology.
- Infectious mononucleosis.
- Diseases of the biliary tract: cholestasis, cholangitis.
- Heart failure of various etiologies with right ventricular dysfunction. This leads to stagnation of a large range of blood circulation, including the development of portal hypertension.
- Toxic hepatitis. Caused by exposure to ethanol, trichlorethylene, carbon tetrachloride, certain poisons and heavy metal salts.
- Metabolic disorders of the liver. This includes, first of all, fatty hepatosis. It is caused by a metabolic disorder in the liver.
- Use of certain medications. In the first place is paracetamol. Of great importance are antibacterial preparations of groups of cephalosporins, sulfanilamides.
In addition to alanine aminotransferase, ALT is higher than normal in certain pathologies of the cardiovascular system. This is myocardial infarction and thromboembolism of the pulmonary arteries. But here it is necessary to take into account the fact that the increase in transferase is much lower. This is largely due to both its low activity and the predominance of aspartate-aminotransferase.
Principles of therapy for aminotransferase enhancement
Regardless of the cause, treatment with elevated alanine aminotransferase primarily involves exposure to the cause of its occurrence. That is, the leading importance is etiotropic therapy
- Elimination of the cause of cell destruction.
- Deceleration and the maximum possible stop of cell destruction.
The choice of drugs and techniques for eliminating the cause, it is also determined. In viral hepatitis, antiviral drugs are considered to be paramount. In case of toxic damage to the liver - methods of detoxification therapy. Disturbances of hepatocytes on the background of heart failure imply mandatory correction of cardiovascular pathology.
As for symptomatic agents, they are indicated in all cases of liver damage. With the only difference is that the dose depends on the severity of this damage. So if the processes of inflammation are sufficiently pronounced and / or predominate over the damage, glucocorticosteroids are prescribed. For the opposite situation, different hepatoprotectors are used: heptral, ursosan, liv-52, etc.
Without the use of hepatic pathology treatments, it is impossible to decide how to reduce the content of aminotransferases. Therefore, in the case of high numbers of transaminases, adequate etiotropic treatment is needed, not folk methods or any "special" diet.
Lowering of aminotransferase: the cause and principles of treatment
The situation in which alanine aminotransferase is lowered is much less common. Since the complete absence of an enzyme in the blood means a profound violation of the exchange of amino acids. This certainly affects the overall metabolism. Such patients often seek medical help for other diseases and the identification of a complete absence of aminotransferases by many doctors is either not perceived: there are more important violations.
The most common decrease in alanine aminotransferase is caused by the following situations.
- Alimentary reasons. Lack of vitamin B6.Because his molecule takes an active part in the synthesis of transaminase. Absolute inadequacy of the enzyme is observed here - it is simply not synthesized in sufficient quantity.
- Dialysis. It is characterized by relative deficiency of the enzyme. The formation of the enzyme is at a sufficient level. But during the process of plasma ultrafiltration, many molecules are removed from the blood during the hemodialysis session. This fate bears upon the aminotransferase.
- Hepatic failure and cirrhosis. Deficiency of the enzyme is caused by a decrease in the number of cells that produce it.
Approaches to therapy in these situations are slightly different from those with high enzyme numbers. So in the case of aminotransferase deficiency against dialysis, no treatment is required. Here there is only a relative deficit and it does not in any way affect the intracellular activity of the enzymes.
Two other situations require certain measures. If the deficiency is caused by nutritional factors, the only true strategy of therapy is an additional increased intake of pyridoxine( vitamin B6).
With the development of liver failure, treatment is similar to situations where there is an increase in alanine aminotransferase. That is, such patients should be assigned hepatoprotective therapy: treatment that slows down the destruction of liver cells and affects its pathology.Like the article? Share with friends and acquaintances: