Oxidative stress in chronic liver disease: relationship between peripheral and hepatic measurements.

Introduction: Oxidative stress plays an important role in the pathogenesis of many liver diseases. Investigators often measure markers of oxidative stress in peripheral veins as a reflection of hepatic oxidative stress as it is not always feasible to measure oxidative stress in liver tissue. However, it is unknown whether markers of oxidative stress measured from peripheral sites accurately reflect hepatic tissue oxidative stress. The aim of this study is to examine the relationship of oxidative stress marker among hepatic tissue, hepatic and peripheral veins and urine.

Methods: Malondialdehyde (MDA), a marker of oxidative stress was measured in hepatic vein, peripheral vein and urine samples from 26 consecutive patients undergoing transjugular liver procedures. In 19 patients undergoing liver biopsies, we measured MDA by immunohistochemical staining of paraffin-embedded liver tissue.

Results: Peripheral venous MDA levels showed significant correlation with hepatic venous MDA levels (r = 0.62, P = 0.02), but they did not correlate with hepatic tissue MDA content (r = 0.22, P = 0.4). Hepatic venous MDA levels did not correlate with hepatic tissue MDA content (r = -0.01, P = 0.9). Subgroup analysis of patients without portal hypertension showed a positive correlation between hepatic venous and hepatic tissue MDA levels, but this was not statistically significant (r = 0.45, P = 0.22). Urinary MDA did not correlate with MDA from any other sampling location.

Conclusion: Oxidative stress measured from the peripheral venous samples is poorly reflective of hepatic tissue oxidative stress. Hepatic venous sampling might be suitable for assessing hepatic tissue oxidative stress in patients without portal hypertension, but a larger study is needed to examine this possibility.