Humic acid-mediated oxidative damages to human erythrocytes: A possible mechanism leading to anemia in Blackfoot disease

Humic acid (HA) has been proposed as a factor that causes Blackfoot disease , an endemic peripheral vascular disease prevailing in the southwest coast of Taiwan. However, the relationship between HA and anemia associated with Blackfoot disease remains unclear. In this study, we showed that HA imposed damages on human red blood cells (RBCs),which were manifested as reduction in deformability of RBCs and hemolysis. At concentrations ranging from 10 to 100 mu g/ml, HA caused lipid peroxidation in a dose-dependent manner. Su ch changes were accompanied by a depletion of glutathione and a reduction i n activities of the antioxidant enzymes including catalase, superoxide dism utase, and glucose-6-phosphate dehydrogenase. These results indicate that H A initiates oxidative stress on RBCs and results in their dysfunction. Cons istent with our previous findings, the present study supports the notion th at HA plays an important role in the pathogenesis of Blackfoot disease. (C) 1999 Elsevier Science Inc.