Reduced angiotensin converting enzyme plasma activity in scleroderma. A marker of endothelial injury?

Decreased levels of angiotensin converting enzyme plasma activity were found in systemic sclerosis. No relationship with clinical characteristics of the disease and increased von Willebrand factor antigen concentration (a widely accepted marker of endothelial injury) were statistically demonstrated. An inverse relationship between the reduced activity of the enzyme and erythrocyte sedimentation rate was detected (r = 0.410, p less than 0.05). We hypothesize that in systemic sclerosis, angiotensin converting enzyme activity might be affected by a decrease in endothelial production or by interference of circulating factors. Further studies are needed to determine if angiotensin converting enzyme activity could be used as a marker of endothelial injury in scleroderma.