P3NP (PIIINP) ELISA

Procollagen type III

is synthesized in fibroblasts as a biosynthetic precursor of collagen type III, and then released. The propeptides are split off in the extracellular space during the conversion into collagen. The N-terminal propeptide (PIIINP; MW 45000) is formed during this process in equimolar proportions to collagen type III and enters the circulation. Bloodstream levels of PIIINP can therefore be used as a measurement of collagen III synthesis.

2.1. Clinical significance of quantitative procollagen III N-terminal peptide determination
The main collagens found in the connective tissue of the liver are types I and III. If, as a result of pathological conditions, there is active proliferation of connective tissue (fibrosis) in the liver, increasing amounts of procollagen III N-terminal peptide are formed. The transformation of functioning liver tissue into connective tissue is detectable by means of the raised bloodstream procollagen III N-terminal peptide level. This is, for instance, the case in:

- alcoholic or virus induced forms of liver fibrosis and cirrhosis
- cases of nonalcoholic steatohepatitis (NASH)

Also, the European S3 Guidelines on the systemic treatment of psoriasis vulgaris recommend that PIIINP measurements be included in laboratory controls to monitor the risk of liver fibrosis in psoriasis patients receiving methotrexate.

2.2. Pathological values
Pathological conditions affecting the liver, which are associated with active proliferation of connective tissue, give rise to raised serum PIIINP values. Therefore, the transformation of functioning liver tissue into connective tissue can be detected by measuring P3NP in the serum. According to the degree of severity of the disease, PIIINP in the serum is raised in chronic active hepatitis, fibrosis and cirrhosis of the liver. Levels in chronic persistent hepatitis are generally in the normal range; procollagen III peptide may be raised in degeneration of the liver. In acute hepatitis procollagen III peptide in the serum is also raised. There are, however, other conditions in which PIIINP is raised without a detectable change in the liver (e.g.pulmonary fibrosis, rheumatic disorders, myocardial infarction, acromegaly, multiple trauma). The diagnostic importance is in monitoring the course of the disease. There is a good correlation with histological findings in fibrosis and cirrhosis.

Distributed by TECAN-IBL International GmbH