Evidence for age-related differences in human fibrinogen

Area of Science:

• Biochemistry
• Hematology
• Pediatrics

Background:

• Fibrinogen exists in a 'fetal' form in neonates, characterized by increased sialic acid and altered functional properties compared to adult fibrinogen.
• The transition of 'fetal' fibrinogen to the adult form and its physiological significance throughout childhood remain largely uncharacterized.

Purpose of the Study:

• To investigate the persistence of 'fetal' fibrinogen characteristics in a 'childhood' form from infancy to adulthood.
• To determine the functional activity and molecular weight differences of fibrinogen across various age groups.

Main Methods:

• Comparative analysis of fibrinogen concentration and functional activity in neonates, children, and adults.
• Assessment of the molecular weight of the Aα fibrinogen chain using techniques like SDS-PAGE.

Main Results:

• Neonatal fibrinogen concentration is decreased but functionally comparable to adult levels.
• Fibrinogen in neonates and children (3 days to 11-16 years) exhibits functionally higher activity than adult fibrinogen, despite lower concentrations.
• The Aα fibrinogen chain shows a consistently higher molecular weight (up to 1500 Da) in neonates and children compared to adults, indicating age-specific posttranslational modifications.

Conclusions:

• Fibrinogen exhibits age-specific molecular and functional differences from infancy through adulthood.
• These age-related variations in fibrinogen may contribute to a protective mechanism against excessive polymerization and proteolysis, explaining the thromboprotective state observed in neonates and children.