Age-related changes in factor VII proteolysis in vivo

Area of Science:

• Biochemistry
• Hematology
• Gerontology

Background:

• Previous studies linked higher proteolysed factor VII and thrombin-antithrombin III levels to post-operative deep vein thrombosis (DVT) in patients over 40.
• The relationship between age, factor VII proteolysis, and DVT risk in post-operative patients remained unclear.

Purpose of the Study:

• To investigate age-related changes in coagulation factors: total factor VII protein, factor VII zymogen, factor VIIa, tissue factor pathway inhibitor, thrombin-antithrombin III, and prothrombin fragment 1 + 2.
• To explore the correlations between these parameters in normal plasma.
• To determine if age influences factor VII proteolysis and its association with DVT risk.

Main Methods:

• Measured concentrations of total factor VII protein, factor VII zymogen, factor VIIa, tissue factor pathway inhibitor, thrombin-antithrombin III, and prothrombin fragment 1 + 2 in plasma samples.
• Analyzed age-related trends in these coagulation parameters.
• Employed linear regression analysis to assess correlations between specific factors, particularly factor VIIa and prothrombin fragment 1 + 2.

Main Results:

• Statistically significant increases in most measured parameters, except thrombin-antithrombin III, were observed with increasing age.
• Significant differences in total factor VII protein and factor VII zymogen (indicating in vivo proteolysis) were found only in individuals over 40.
• A significant positive correlation was identified between plasma factor VIIa and prothrombin fragment 1 + 2 concentrations.

Conclusions:

• Elevated plasma factor VIIa in individuals over 40 suggests less regulated tissue factor activity and increased thrombin generation.
• This heightened thrombin production is hypothesized to contribute to the increased risk of post-operative thrombosis in older adults.
• Age is a significant factor influencing coagulation dynamics and DVT risk.