Leukocyte activation in patients with venous insufficiency

Purpose: Cell activation may play an important role in the production of ve nous insufficiency, just as leukocytes participate in the cause of venous u lcer. If activated, monocytes observed on venous endothelium can migrate in to the venous wall and produce toxic metabolites and free oxygen radicals t hat may participate in valve destruction and venous wall weakening. At pres ent, it remains uncertain to what degree leukocytes are actually activated in patients. This study was designed to explore the level of activation and to examine whether patient plasma contains an activator that lends to leuk ocyte activation of unstimulated naive leukocytes from volunteers without v enous insufficiency disease. Methods: Twenty-one patients (4 men, 17 women), who ranged in age from 34 t o 69 years (mean age, 53.2 years), with chronic venous disease were compare d with 16 healthy control volunteers (4 men, 12 women), who ranged in age f rom 18 to 65 years (mean age, 48.4 years). ALL the patients underwent evalu ation with Doppler ultrasound scanning and were classified with the CEAP sc ore.(1) Nearly all the patients who smoked or were hypertensive were exclud ed. The blood types (ABO and Rh) of the controls were matched to the study group. Isolates of patient whole blood, plasma, or leukocytes were incubate d with isolates of control whole blood, plasma, or leukocytes to separate a ctual activation from spontaneously observed activation. The granulocyte ac tivation was measured with nitroblue tetrazolium (NBT) reduction and quanti tation of granulocyte pseudopod formation. Hydrogen peroxide production in patient plasma was measured with a recently developed electrode method. Results: Leukocytes from healthy blood and patient plasma had significantly higher NET-positive,granulocyte counts than either patient blood, healthy blood, or patient blood incubated in healthy plasma. In a comparison of pat ient groups across the CEAP classes, the NET-positive granulocyte counts we re significantly greater in classes 4, 5, and 6 than in classes 2 and 3 (P <.001). Pseudopod formation was significantly greater in mixtures of granul ocytes in healthy blood and patient plasma than in all other groups. There was no difference in the level of pseudopod formation in control leukocytes incubated with patient plasma in patients across the CEAP spectrum. The pa tient plasma produced significantly higher hydrogen peroxide values than di d the controls. Conclusion: These results suggest that patient plasma may contain an activa ting factor for granulocytes. The finding that activated neutrophils were f ewer in number in patient whole blood than in healthy blood incubated in pa tient plasma could suggest that activated neutrophils in patients with chro nic venous insufficiency might be crapped in the peripheral circulation. It is unknown what factors in the plasma might induce activation of naive neu trophils, but such activators could possibly be important in the pathogenes is of primary venous dysfunction and the development of chronic venous insu fficiency.