FTY720 application following isolated warm liver ischemia improves long-term survival and organ protection in a mouse model.

BACKGROUND: Ischemia-reperfusion-Injury (I/RI) is a common complication in transplant-, liver-, and heart surgery. The I/RI is mediated and aggravated by different types of leukocytes such as lymphocytes, monocytes, and neutrophil granulocytes, with consecutive enlargement of the expression of adhesion molecules. This study shows an organ-protective effect of an intraoperative FTY720 administration following warm liver ischemia (Pringle's maneuver). METHODS: Male c57BL6/J mice (n = 46, body weight [BW] 25 to 30 g) were used. Either FTY720 (1 mg/kg BW), steroids (5 mg/kg BW), or physiological saline solution was administered intraperitoneally. Liver-ischemia was applied for 30 minutes with subsequent follow-up for 48 hours. At termination, all surviving animals were sacrificed. The impact of the drugs administered on long-term survival, time of death, and development of blood T-lymphocyte concentration was determined. Follow-up of T-lymphocyte concentration in peripheral blood was examined throughout FACS-analysis. RESULTS: Following 30 minutes of ischemia, FTY720, but not steroid or vehicle treatment, showed a significant protective effect on long-term survival. FACS-analysis showed significant T-lymphocyte depletion in peripheral blood following FTY720 but not steroids or vehicle treatment. CONCLUSION: The improved long-term survival following FTY720 application shown in this study might be due to a protective effect of FTY720 in prevention of I/RI. This might be mediated by the T-lymphocyte depletion shown in the FACS-analysis.

FTY720 for treatment of ischemia-reperfusion injury following complete renal ischemia; impact on long-term survival and T-lymphocyte tissue infiltration.

BACKGROUND: Organ dysfunction due to ischemia-reperfusion (I/R) injury is a common problem in transplant, liver, trauma, and heart surgery. I/R injury is mediated by upregulated expression of endothelial cell surface adhesion molecules and subsequent adhesion and activation of circulating leukocytes. The purpose of this study was to evaluate the effect of an intraoperative administration of FTY720 in an animal model with controlled bilateral warm kidney ischemia compared to steroids or placebo application. METHODS: Male C57BL6/J mice (n = 72, weight 25 to 30 g) were exposed to 30 minutes of bilateral kidney ischemia and followed by a 48 hour observation period. FTY720 (1 mg/kg body weight [BW]), steroids (5 mg/kg BW), or saline solution were administered. In addition, a sham-operated control group was included. At the termination of the experiments, all surviving animals were humanely killed. The impact of the various drugs on overall animal survival, timing of death, peripheral T-cell count, and T-lymphocyte infiltration in the kidneys was determined. RESULTS: Following bilateral kidney I/R injury, FTY720 was associated with a significant improved animal survival (85.7%) compared with steroids (50%) or controls (42.4%). FACS analysis showed significant T-lymphocyte depletion in peripheral blood in the FTY720 but not in the other groups. T-lymphocyte tissue concentration in liver and kidney tissue did not show statistically significant differences following FTY720, steroid, or saline treatment. CONCLUSION: FTY720, when administered intraoperatively, improved survival significantly in mice submitted to bilateral kidney ischemia but did not have any significant impact on the parenchymal T-lymphocyte infiltration in the ischemic organ.

FTY720 for treatment of ischemia-reperfusion injury following complete renal ischemia in C57/BL6 mice.

BACKGROUND: Organ dysfunction followed by single-organ or even multiorgan failure due to ischemia-reperfusion injury (I/RI) is a common problem in liver and heart transplantation. Various approaches had been attempted to prevent this I/RI. One is the administration of FTY720, a synthetic structural analogue of sphingosine, which induces T-lymphocyte homing with consecutive lymphopenia. The purpose of this study was to evaluate the effect of intraoperative FTY720 administration following controlled bilateral kidney ischemia in comparison to steroid or placebo application. METHODS: Male c57BL6/J mice (n = 115; body weight 25 to 30 g) received either FTY720 (1 mg/kg body weight) or steroids or saline solution. Ischemia was applied for 30 or 60 minutes with subsequent follow-up for 48 hours. At termination all surviving animals were sacrificed. RESULTS: Following 30 minutes of ischemia, FTY720, but neither steroid nor vehicle treatment showed significant protective effects on long-term survival after controlled bilateral warm kidney ischemia. Fluorescein-activated cell sorting (FACS) analysis showed a significant T-lymphocyte depletion in peripheral blood after FTY720 treatment, which was not observed after steroid or vehicle treatment. CONCLUSION: The improved long-term survival shown in this study might be due to a protective effect of FTY720 to prevent I/RI, which may be mediated by the lymphocyte depletion shown in the FACS analysis.

Filtration of malignant cells: tumour cell depletion in an ex vivo model using a leukocyte adhesion filter.

The clinical use of leukocyte adhesion filters is based on differentiated depletion of blood cells, although most of the mechanisms of filtration are still unclear. There is also evidence that leukocyte adhesion filters can remove disseminated tumour cells from patients' blood. The following proves this observation and consists of three parts: in the first part we analysed the depletion capacity of the LeucotrapWB filter medium (Pall) in an employed small-scale model for the cell line HT29 (colorectal origin) in phosphate-buffered saline (PBS) solution. A depletion rate of more than 99.6% for HT29 cells was seen. In the second part of the study, samples of whole blood were spiked with HT29 cells in a similar setting, showing comparable results. In the last part, defined cell suspensions of various human primary tumours were admixed to whole blood samples and afterwards filtrated in a scale-up model. Again, a nearly complete tumour cell reduction was seen after filtration. Results show a significant tumour cell reduction and, for most cases, a complete depletion of tumour cells independently from quality and origin of the tumour tissue. These experiments and further investigation are supposed to help to reduce the risk of dissemination of tumour cells in patients undergoing oncological surgery.

Feasibility of veno-venous bypass surgery using leukocyte adhesion filters during abdominal surgery in a porcine model.

During oncologic surgery, manipulation of tumour tissue is almost unpreventable; liver resection even carries a higher risk of tumour cell dissemination into venous blood. Under in vitro conditions, a tumour cell reducing effect of some leukocyte adhesion filter systems has been shown. In a preclinical porcine model, these filters were used as integrated parts of a veno-venous bypass system used for liver surgery, run by a biopump. Practicability, handling and safety aspects of the filter system were analysed; the system was easy and safe to handle, and treated animals survived without any complications. For the future, effectiveness of the tumour cell depletion has to be examined in further experimental and clinical studies.