Abstract:
During aging, changes in vasculature, haemostasis
and endothelium, including alterations of platelets,
coagulation and fibrinolytic factors, occur. Research has also
reported that healthy, aged individuals have heightened coagulation
enzyme activity, accompanied by signs of enhanced
formation of fibrin and secondary hyperfibrinolysis. It is now
believed that the impaired fibrinolytic potential in old age
results in a condition that has previously been described as a
systemic state of ‘‘thrombotic preparedness’’. This state is
far out of proportion to the physiological needs of the person.
In the current research we investigate whether this apparent
changed thrombotic profile in healthy aged individuals (over
the age of 75), is evident in their platelet and fibrin network
ultrastructure, when compared to healthy individuals under
25 years. The main differences among young and older individuals
were found in the fibrin network ultrastructure. It is
concluded that with age, major fibers seem to become thinner
and more sparsely arranged and that minor, thin fibers dominate
it the coagulum, forming a fine netlike structure. At
irregular intervals in the coagulum, thicker, fibrin fiber lattices
are present; this is not found in healthy individuals. This
might be due to the previously suggested enhanced fibrin
formation and heightened coagulation enzyme activity. Here
we therefore provide ultrastructural evidence for the thrombotic
preparedness previously suggested after studying biochemistry
of fibrinolysis and coagulation factors in the
elderly.
