Role of Human Polymorphonuclear Neutrophils in Endothelial Cell Damage Induced by Shiga Toxin-1 and Inflammatory Agents.

LANDONI, V; NEGROTTO, S; D’ATRI, P; RAMOS, V; FERNANDEZ, G; PALERMO, M; SCHATTNER, M; ISTURIZ, M

Sydney, Australia

Congreso; XX ISTH Congress; 2005

The Hemolytic Uremic Syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia and acute renal failure. Typically, HUS develops in young children as a vascular disease followed by bloody diarrhea. HUS is generally caused by gram-negative with serotype of Escherichia coli producing Shiga toxins (Stx). It has been suggested that Stx is necessary but not sufficient to induce endothelial damage, it is also required inflammatory agents. In addition, neutrophil leukocytosis correlates with poor prognosis, although it is not clear if this is an epiphenomenon or is a necessary element for the development of renal damage. Considering this, the aim of this work is to determine the importance of neutrophils (PMN) in the endothelial damage induced by Stx-1 and inflammatory agents like LPS, TNF-alpha and IL-1 beta. Human umbilical vein cord cells (HUVEC) were incubated for 24 h with inflammatory stimulus and STx-1 (5ng/ml). Then, cells were washed, and the PMN added. The citotoxic effects on the endothelium were evaluated after 24 h by microscopy after staining the cells. Results are expressed as damage percentage respected to controls ± SD: LPS + Stx: 43±3, Stx + PMN: 45±6, LPS + Stx + PMN: 95±4. Similar results were obtained with TNF-alpha and IL-1 beta. These results suggest that inflammatory agents are necessary but not sufficient to induce significant Stx-1 dependent endothelial toxicity. The presence of PMN is required to obtain the maximal damage. This fact may explain the correlation between the poor prognosis in HUS and the augmented PMN counts.