Factors affecting gamma-chain multimer formation in cross-linked fibrin

Area of Science:

• Biochemistry
• Hematology
• Molecular Biology

Background:

• Fibrin cross-linking by factor XIIIa is crucial for blood clot stability.
• Plasmic digests of cross-linked fibrin yield multimolecular D fragments, including D dimers, trimers, and tetramers.
• These fragments arise from cross-linked gamma chains (gamma dimers, trimers, tetramers) via epsilon-amino-gamma-glutamyllysine bonds.

Purpose of the Study:

• To investigate factors influencing the formation of D trimers and D tetramers.
• To analyze the dynamics of gamma-chain cross-linking in fibrin under various conditions.

Main Methods:

• Analysis of D-fragment content in plasmic digests of cross-linked fibrin.
• Sampling of digests after complete gamma-chain monomer consumption.
• Varying factor XIII concentration, cross-linking time, CaCl2 concentration, and ionic strength (NaCl).

Main Results:

• D trimers and D tetramers increased with higher factor XIII, longer cross-linking time, and increased CaCl2 concentration.
• Higher ionic strength (NaCl) decreased D trimer and tetramer formation, an effect reversible by CaCl2.
• Clots from recalcified plasma showed increased D trimers and tetramers with longer incubation times.

Conclusions:

• Gamma-trimer and gamma-tetramer formation is a dynamic physiological process.
• Factor XIII concentration, cross-linking duration, CaCl2, and ionic strength modulate the extent of gamma-chain cross-linking.
• These findings provide insights into the structural dynamics of stable blood clots.