Reaction of Human Endothelial Cells to Bovine Hemoglobin Solutions and Tumor Necrosis Factor

Abstract

Human umbilical vein endothelial cells (HUVEC) were incubated for 24 hours with 0.1mM or 0.3 mM of: [A] unmodified (U) Hb-Fe^IIO₂; [B] UHb-Fe^III; [C] UHb-F^IV-OH; [D] polymerized low molecular weight Hb(< 400 kDa); [E] polymerized high molecular weight Hb(< 1,020 kDa); [F] polymerized low molecular weight Hb + Endoioxin (2.5 EU/mL); [G] rTNFα 100 pg/mL; [H] rTNFα 400 pg/mL; [I] rTNFα 800 pg/mL. The medium of the incubation was tested for LDH (index of cell injury), and for cytokines GM-CSF and IL-1α released by the cells. The data suggests that oxidation status of the iron in the Hb molecule and concentration of Hb play an important role in causing EC injury. The highest toxicity was observed when EC were incubated with 0.1mM of UHb-Fe^IV-OH (ferryl-Hb) and no toxicity with 0.3 mM of Hb-Fe^III (ferric-Hb). The direct stimulation of EC by Hb for the production of IL-1 was limited, related only to high molecular weight Hb polymers or to Hb+E, however GM-CSF expression was increased by almost all Hb forms. TNF induced dose-related injury (R² = 0.986), and dose-related release of IL-1 (R² = 0.977). A different EC reaction was observed on the release of GM-CSF. Intermediate levels of TNF (400 pg/mL) increased the expression of this cytokine, while high levels (800 pg/mL) blocked its release.