What is the elastase?
definition
An elastase is the active form of an enzyme that arises from the so-called proenzyme or zymogen proelastase through limited proteolysis. This means that by splitting off some amino acids, the inactive form is converted into the active form.
Elastase is an enzyme that can break the peptide bond between two amino acids in the middle of a protein using water. The protein elastin is one of the typical substrates that are split. Overall, there are several forms of elastase. There is granulocyte elastase, which is found in certain immune cells, pancreatic elastase, which is produced by the pancreas, and other lesser-known forms.
Task and function of elastase
Depending on the type, elastase has different tasks. The most common form of elastase, pancreatic elastase, which is produced by the pancreas, plays an important role in digestion. The enzyme is responsible for part of the digestion of proteins that are ingested with food. The pancreatic elastase breaks down the amino acid chain like other enzymes that serve to digest proteins.
It is not opened from the ends, but works within the chain. It is therefore one of the endopeptidases. This splits proteins into several amino acid sequences, each of which is only a few amino acids in length. This means that they are subsequently broken down into individual amino acids by further enzymes, which occur in large numbers, and these can easily pass through the mucous membrane of the small intestine into the bloodstream. The enzymes that break down the chain of amino acids from the ends are called exopeptidases.
In addition to its action in the intestine, the enzyme elastase can take on other tasks in the body, some of which are also harmful to the body. When certain diseases occur, elastase can occur in the area of the lungs and break down the structural protein elastin. This structural protein is responsible, among other things, for the elasticity of the lungs, which can lead to functional restrictions if it is broken down.
In addition to pancreatic elastase, leukocyte elastase, also called granulocyte elastase, is a widespread form of the enzyme. This occurs in special cells of the immune system, the granulocytes, and is particularly important in the defense against microorganisms.
Without adequate regulatory mechanisms, the function of elastase would last long enough, which would have negative effects on the human body. The elastase could break down the body's own proteins, which would then lose their function. This is the reason why the human body makes inhibitors that can decrease and cancel the activity of elastase. These are used, for example, in pancreatic elastase while the secretion from the pancreas is still in the ducts. The inhibitors prevent activation too early, so that the body's own tissue does not digest.
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What is an elastase inhibitor?
An elastase inhibitor is a protein that reduces the activity of elastase. Thus, to a lesser extent, the elastase is able to split and break down the amino acid chains of proteins. Elastase inhibitors belong to the group of proteinase inhibitors that are widely distributed in the body and made in many organs. Like elastase inhibitors, they decrease the activity of enzymes that break down proteins.
This is an important protective mechanism of the body to prevent an excessive reaction. Elastase inhibitors are contained in the secretion of the pancreas, for example, and prevent the elastase from being activated too early in the pancreatic ducts so that the body cannot be digested.
Where is the elastase formed?
Depending on the type of elastase, it is produced in different tissues. The most common variant, pancreatic elastase, is produced in the exocrine part of the pancreas, the part whose secretion flows through ducts into the duodenum of the small intestine.
Granulocyte elastase plays a role in the immune reaction and occurs in special immune cells called granulocytes. Production takes place in these cells. Since these cells move with the blood through the body and often pass into the tissue, they cannot be assigned to any specific organ with regard to the production of elastase.
In addition to these two known forms of elastase, there are other variants, some of which are also produced in immune cells and some in other tissues.
What is the elastase test?
The elastase test is a procedure that measures the amount of elastase that is excreted in the stool. The amount of pancreatic elastase is always observed here. This test procedure is used to determine the performance of the exocrine part of the pancreas. The test procedure is based on the fact that after the active pancreatic elastase has been secreted into the intestine, the amount of active elastase present in the pancreas remains constant. This means that the elastase performs its task as an enzyme, but is not used up in the process. This allows a direct, linear relationship to the synthesis performance of the exocrine pancreas to be made from the amount of pancreatic elastase determined in the stool.
This test is very sensitive, which means that even small deviations can be detected quickly and reliably, provided a reference value is available. Furthermore, the synthesis capacity of the exocrine pancreas is relatively constant in healthy people, which is why changes are noticed very quickly here. In addition, the elastase test has a high specificity, which means that a positive test result indicates a disease of the pancreas with relative certainty. If the elastase test shows decreased values, this can indicate various diseases.
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What are the normal elastase values?
The amount of pancreatic elastase in adults should be above 200 µg / g in the stool.
The amount of pancreatic elastase in the blood serum should be below 3.5 µg / ml.
In the pancreas, the amount should be between 0.16 g / l and 0.45 g / l.
As with all laboratory values, there are no generally valid values that determine health or illness. On the one hand, the absolute values of a laboratory parameter, such as the elastase value, are subject to physiological fluctuations in every person. This means that a lowered value can be pathological in one person, while it is completely normal in another person. In addition, the standard values are determined differently depending on the laboratory, which is why the stated values of the laboratory should be observed in case of doubt.
What happens when the elastase is low?
Digestion is disturbed if the production of pancreatic elastase is reduced. Since elastase breaks down food proteins into smaller fragments, these are more difficult to absorb in the following sections of the intestine. Diarrhea can also increase. Furthermore, it is possible that not only the exocrine part of the pancreas is affected by an insufficiency with reduced production of proteins for digestion, but also the endocrine part of the pancreas, which is responsible, among other things, for blood sugar regulation, a lack of production of hormones having. This can often lead to disturbances in the blood sugar level. The therapy is based on the failed functions.
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What are the causes of a decreased elastase value?
The reasons for a reduced elastase value in the stool can be varied. If a lower value has been determined, this definitely requires further clarification, as very serious causes are possible in some cases.
Pancreatic cancer is more common. Functional tissue of the pancreas is replaced by non-functional tumor tissue.
Furthermore, a narrowing of the duct of the pancreas can lead to reduced values. This narrowing can have several causes such as gallstones. As untreated, your own body tissue can digest, you should intervene immediately.
Other reasons for a low elastase level can be chronic inflammation of the pancreas, so-called chronic pancreatitis, a cyst, pancreatic insufficiency or cystic fibrosis.
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- Pancreatic cancer
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What can increase elastase levels?
Elevated elastase levels are usually not found in the stool, but in the blood. This leads to an increased transfer into the blood, which can have several reasons.
With acute inflammation of the pancreas or an attack of chronic pancreatitis, the blood vessels become more permeable, allowing elastase to enter the blood.
In addition, if the pancreatic outflow is disturbed, a backflow with increased pressure can occur, which enables the elastase to pass into the blood vessels. Severe liver disease, gallstone disease or pancreatic cancer can be responsible for the backlog.
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What is leukocyte elastase?
The leukocyte elastase is also known as granulocyte elastase because it occurs and is formed in the granulocytes. Like pancreatic elastase, leukocyte elastase also cleaves compounds of amino acids in a protein. As a result of an immune response, the granulocytes, also known as phagocytes, take harmful objects such as bacteria into the cell and begin to do so Dismantling these objects. The so-called leukocyte elastase is effective here. Since this elastase is only unspecifically effective, damage to the body's own tissue also occurs, which is to be prevented by the formation of elastase inhibitors.
What does elastase do to the lungs?
Elastase also occurs in the lungs in the context of some diseases.
If there is a lack of elastase inhibitors such as alpha-1-antitrypsin, it can lead to increased activity of elastase in the lungs. Here, like everywhere else in the body, elastase breaks down proteins, but this affects the body's own tissue in the lungs. Structural proteins such as elastin, which are largely responsible for the elasticity of the lungs, are mainly attacked. This leads to massive damage to the lung tissue, which inevitably restricts lung function.
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