Neutrophil Activation in Experimental Venous Hypertension

Abstract

Objective: To investigate the white cell trapping hypothesis of venous ulceration by measuring plasma lactoferrin as a marker of neutrophil degranulation in normal volunteers in two experimental models of venous hypertension. Design: A prospective study of volunteers with no history or clinical evidence of venous disease. Setting: The Middlesex Hospital Vascular Laboratory, Mortimer Street, London WIN 8AA, UK. Patients: Volunteers within the Middlesex Hospital Vascular Laboratory with no history or clinical findings of venous or arterial disease, no other systemic disease, on no medication known to alter white cell activity, and with no recent infection. Interventions: Venous blood was taken from cannulae in both feet and the right arm for a neutrophil count and Plasma lactoferrin, measured using an ELISA, during application of a tourniquet to 80 mmHG for 30 min to the right leg while supine, 5 min after release of tourniquet, and then during a 30 min period of standing. Results: During application of a tourniquet to the right leg there was a significant rise in plasma lactoferrin and in lactoferrin corrected for the neutrophil count ( p < 0.05, Wilcoxon). In the unoccluded leg, although Plasma lactoferrin rose, this was not significant when corrected for the rise in neutrophil count. After standing for 30 min, the lactoferrin and neutrophil count increased in all three limbs; corrected lactoferrin showed a significant increase in the legs ( p < 0.02), though not in the arm. Conclusion: Increased neutrolphil degranulation occurs during periods of short-term venous hypertension in normal volunteers, in keeping with the white cell trapping hypothesis.