Isoenzymes of alkaline phosphatase

General Information

Alkaline phosphatase in serum

It is used: in the diagnostics of pathologies of the liver, bones, intestines and parathyroid glands.

Alkaline phosphatase (ALP) isoenzymes are classified into several groups, depending on the organ in which they are synthesized. These are: liver, kidney, bones, intestine, parathyroid glands, placenta and others.

The serum nitrogen phosphatase activity is the sum of the activities of the nitrogen phosphatase isoenzymes in these tissues.

Serum nitrogen phosphatase activity is an especially important marker for evaluating the state of the hepatobiliary and bone systems.

Tutephosphatase is an important bone marker because it is synthesized by bone cells and indicates increased activity of osteoblasts in diseases such as Paget's disease, rickets, osteomalacia, fractures, bone tumors.

A moderate increase in alkaline phosphatase can be observed in Hodgkin's disease, congestive heart failure, ulcerative colitis, regional enteritis, bacterial diseases of the abdominal cavity.

Total alkaline phosphatase

Total alkaline phosphatase is a combination of alkaline phosphatase synthesized by all tissues. Its half-life in serum is 17 days.

An increase in total alkaline phosphatase (3 times, compared to the norm) is observed in extrahepatic obstruction of the bile ducts (in the case of suffocation with stones or pancreatic head tumor). The higher the degree of obstruction, the higher the level of alkaline phosphatase. Simultaneous increase of alkaline phosphatase (ALP) and gammaglutamyltransferase (GGT) is a sure sign of liver damage.

In bone pathologies, the highest ALP activity is observed in Paget's disease, which is associated with an imbalance between osteoblasts and osteoclasts. In osteoporosis, osteomalacia and rickets, a moderate increase in sodium phosphatase is observed.

Primary and secondary hyperparathyroidism are associated with moderate elevations of alkaline phosphatase. Higher activity may indicate the involvement of bone processes.

A moderate increase in alkaline phosphatase is also seen in children with acceleration of bone growth.

A moderate increase in alkaline phosphatase is observed in the third trimester of pregnancy, and the enzyme is mainly of placental origin.

Isoenzymes of alkaline phosphatase

Liver Nitrogen phosphatase is one of the isoenzymes synthesized in the biliary endothelium. It is sensitive to biliary tract obstruction and in response to increased concentration of bile acids, hepatic alkaline phosphatase synthesis is also activated.

An isolated increase in liver alkaline phosphatase indicates infiltrative diseases of the liver, such as: primary tumors, abscess, granuloma, amyloidosis, primary or sclerosing cholangitis, acquired immunodeficiency syndrome, cholangitis associated with Ig G4 and others. In patients with sepsis, elevated ALP concentrations may be associated with progression of secondary sclerosing cholangitis to cirrhosis.

 Liver alkaline phosphatase 1AP isoenzyme An increase in activity is observed in non-malignant liver pathologies (cholestasis, viral hepatitis, other biliary pathologies). It is also increased in liver metastases and lymphomas of malignant tumors of the lung and digestive tract.

Liver alkaline phosphatase 2AP isoenzyme The increase is observed during cirrhosis and viral hepatitis, as well as during liver metastasis of breast, liver, lung, prostate, digestive tract tumors.

Enzyme levels may remain high for up to 1 week after the liver obstruction is resolved.

Alkaline phosphatase non-hepatic Forms include bone, intestinal, kidney and placenta isoenzymes. An increase in its concentration is observed in bone diseases, osteoblastic tumors, small intestine obstruction and normal pregnancy.

bone  Alkaline phosphatase isoenzymes are elevated in osteoblastic bone tumors (Paget's disease). A particularly high concentration of nitrogen phosphatase is characteristic of osteogenic carcinomas.

intestinal Isoenzyme activity may increase in patients with liver cirrhosis and inflammatory bowel disease.

Placental An increase in nitrogen phosphatase isoenzyme, together with carcino-placental antigen, is observed in various oncological diseases.