N-terminal propeptide of procollagen type III (PIIINP) and methotrexate

Last edited 02/2021 and last reviewed 02/2021

In patients with psoriasis on methotrexate, measurement of procollagen III N-terminal peptide is advised as an indicator of hepatic fibrosis, although this is usually performed in secondarycare (1,2)

What is procollagen III N-terminal peptide?

  • process of liver fibrosis is assumed to be caused by the excess production of extracellular matrix (ECM) in hepatic stellate cells (HSCs) (3,4)
  • the increase of ECM deposited fragments in the Disse's space leads to liver injury
    • largest component of the ECM is collagen
    • in the liver type III collagen mainly occurs
  • during the synthesis of type III collagen, the N-terminal propeptide of procollagen type III (PIIINP) is detached from procollagen type III
    • (5)
    • so the fibrogenesis results in release of ECM fragments into the blood
      • quantity of propeptide of procollagen type III can be a direct indicator of collagen synthesis and its deposition in the extracellular space
      • increased amount of propeptide of type III procollagen may indicate the transformation of normal liver tissue into connective tissue (1,2,3,4)

Notes (6):

  • PIIINP is not a liver-specific marker
    • increased concentrations of PIIINP have also been other conditions associated with abnormal production of collagen
      • for example congestive heart failure, hypertension, coronary heart disease and pulmonary fibrosis

Reference:

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methotrexate