Clinical improvement of sepsis by extracorporeal centrifugal leukocyte apheresis in a porcine model

BACKGROUND: Extracorporeal blood purification therapies targeting removal of the downstream products of the inflammatory cascade in sepsis have failed to improve mortality. As an upstream process of the inflammatory cascade, activated white blood cells should be a potential therapeutic target for sepsis, and the effect of removing such cells by extracorporeal centrifugal leukocytapheresis (LCAP) is worth considering. METHODS: Fourteen peritonitis-induced septic pigs were randomly assigned to receive a sham operation (control group, n = 7) or one session of LCAP at 12 h after sepsis induction (treatment group, n = 7). Samples from peripheral blood at various time-points and from LCAP collection were tested. All pigs were euthanized at 48 h, and lung, kidney, liver and spleen tissues were obtained for histopathological examination. RESULTS: Two pigs died in accidents before the induction of sepsis, and 12 pigs were finally included for the statistical analysis. A significant clinical improvement was present in the treatment group relative to the control group in terms of the mean arterial blood pressure (MAP), oxygen tension (PaO(2)), lactic acid level, oxygenation index (PaO(2)/FiO(2)), and carbon dioxide tension (PaCO(2), P < 0.05). Flow cytometry tests showed that a mixture of B cells, dendritic cells, T helper cells, cytotoxic T cells, monocytes and neutrophils were removed from the circulation by LCAP, resulting in sepsis-induced change trends in the control cells; these change trends were all flattened in the treatment group, although nonsignificantly. CONCLUSIONS: LCAP may exert a wide-spectrum and bidirectional immunomodulatory effect on sepsis, accompanied by improvements in hemodynamics and oxygenation status.