6-ketoprostaglandin-f1-alpha and Venous-Insufficiency

Nineteen patients with symptoms of chronic venous insufficiency (CVI) were treated with 13-week cycles of intermittent pneumatic compression (IPC) during 2 h sessions twice weekly, with most treatments at home. At study completion, quantitative subjective scores for total symptomatology were improved in 16/19 patients (84%). Enhancement of fibrinolytic potential in vivo was detected in 86% of observations on specimens from CVI patients over 2 h of IPC, with accelerated euglobulin clot lysis times (ELT) noted within 15 min of initiating compression. The enhanced fibrinolytic potential was attributed to increased urokinase plasminogen activator (u-PA), probably released from perturbed endothelial cells by IPC. Significant decreases in total t-PA antigen (mass concentration) but not t-PA activity, were produced by IPC in CVI patients only (P = 0.0001), with greater effects noted in the non-anticoagulated versus the anticoagulated cohort. Plasminogen activator inhibitor type 1 (PAI-1) levels rose rapidly after IPC only in the controls and non-anticoagulated CVI patients. PAI-1 decreased in those receiving anticoagulation. No platelet perturbation was detected during IPC by measuring levels of beta-thromboglobulin or the thromboxane A2 metabolite, 11-dehydrothromboxane B2; however, significant (P < 0.003) decreases in plasma prostacyclin (PGI2) levels (measured as the stable 6-ketoprostaglandin F-1-alpha-metabolite) were observed after 15 min of IPC in non-anticoagulated CVI patients only. There was no evidence of increased thrombin generation by IPC, determined by urinary excretion of fibrinopeptide A and prothrombin fragment 1. Concurrent anticoagulation appears to mediate more favorable biochemical alterations in CVI, although subjective improvement did not correlate with anticoagulation. The mechanism(s) by which these physiologic changes compliment the mechanical effects of IPC remain to be elucidated and will require adequately controlled and powered studies.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Aged; beta-Thromboglobulin; Chronic Disease; Female; Fibrinolysis; Humans; Male; Middle Aged; Platelet Activation; Pressure; Thrombophlebitis; Tissue Plasminogen Activator; Venous Insufficiency

The role of aspirin on tissue plasminogen activator (t-PA) release was studied in rats after experimental venous occlusion. For this purpose, we developed a new experimental model which combines a vascular perfusion system (isolated rat hindquarters) with vascular stimulation, namely the application of venous stasis. Application of venous stasis for 30 min induced the release of t-PA from the vascular endothelium into the perfusate (from 0.19 +/- 0.05 to 0.39 +/- 0.05 UI/ml), reaching a peak 90 s after reperfusion. Aspirin administered to rats 60 min before the experiments (100 mg/kg i.v.), or dissolved in Tyrode solution (100 microM), suppressed 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) synthesis (0.38 +/- 0.09 in control and < 0.01 and 0.15 +/- 0.09 ng/ml, respectively, in aspirin-treated groups) but did not prevent the increase in fibrinolytic activity after venous occlusion (from 0.20 +/- 0.04 to 0.38 +/- 0.06 and from 0.07 +/- 0.03 to 0.27 +/- 0.03 IU/ml, respectively, in the aspirin-treated group). Our results suggest that the increase in fibrinolytic activity after experimental venous occlusion in isolated rat hindlegs is modulated by mechanism(s) other than the cyclooxygenase pathway in the vascular wall.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Aspirin; Disease Models, Animal; Endothelium, Vascular; Fibrinolysis; Hindlimb; Ligation; Male; Perfusion; Rats; Tissue Plasminogen Activator; Veins; Venous Insufficiency