title: Activated protein C correlates inversely with thrombin levels in resting healthy individuals.
abstract: To study whether the circulating anticoagulant, activated protein C (APC), could be a regulator of thrombin activity in basal physiological conditions, fibrinopeptide A and activated protein C levels were determined in samples from 40 healthy individuals. There was a significant inverse correlation between the fibrinopeptide A and APC levels (Spearman rank correlation R = -0.487; P = 0.0023). Because of well-known mechanisms by which decreasing APC levels could cause increased thrombin formation, we suggest that APC may downregulate thrombin activity in subjects with normal protein C levels. Regulation of thrombin formation in health is likely significant for maintaining vascular patency but its molecular mechanisms are poorly understood. The current data suggest that a single physiological anticoagulant, namely APC, may be a significant regulator of procoagulant thrombin activity.
authors.affiliation: Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Fernández
authors.forename: J
authors.initials: J
authors.lastname: Petäjä
authors.forename: A
authors.initials: A
authors.lastname: Gruber
authors.forename: J H
authors.initials: JH
authors.lastname: Griffin
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011486:Protein C / Q000502:physiology*; D012146:Rest / Q000502:physiology; D013917:Thrombin / Q000502:physiology*
chemical_list: D011486:Protein C; D013917:Thrombin