Vitamin C modifies the cardiovascular and microvascular responses to cigarette smoke inhalation in man

Both neutrophil margination and increases in the non-invasively assessed pa rameter, isovolumetric venous congestion cuff pressure (Pv(i)), are symptom atic of some inflammatory diseases. Neutrophil margination occurs primarily , though not exclusively, at the post-capillary endothelial surface. The lo cal haemodynamic changes resulting from margination may be responsible for the observed increases in Pv(i). Smoke inhalation has been shown in animal studies to cause an increase in post-capillary neutrophil margination by me chanisms that can be blocked by oral vitamin C administration. We looked fo r indices of a relationship between margination and Pv(i) in man, using cig arette smoke inhalation as a pathophysiological challenge. We also examined the effect of prophylactic vitamin C on the response. Smoke inhalation was associated with highly significant increases in both Pv(i) and heart rate. After vitamin C pre-treatment, no increase in Pv(i) was observed in respon se to the smoke inhalation; however, whilst heart rate still increased sign ificantly, the duration of this response was attenuated. The results sugges t that vitamin C affords protection against some of the cardiovascular and microvascular changes associated with cigarette smoke inhalation in man. Th ey also support the notion that noninvasive assessment of changes in Pv(i) may provide a measurable index of systemic changes in inflammatory conditio ns.