Protection afforded by pyruvate during acute rejection of small-bowel allografts is mediated by inhibition of oxygen-free radicals and cytolytic activity (perforin and granzyme-B mRNA expression) in activated leukocytes

Intravital Imaging of Thrombosis Models in Mice

Intravital microscopy is a powerful tool to study thrombosis in real time. The kinetics of thrombus formation and progression in vivo is studied after inflicting damage to the endothelium through mechanical, chemical, or laser injury. Mouse models of atherosclerosis are also used to induce thrombus formation. Vessels of different sizes and from different vascular beds such as carotid artery or vena cava, mesenteric or cremaster arterioles, can be targeted. Using fluorescent dyes, antibodies, or reporter mouse strains allows to visualize key cells and factors mediating the thrombotic processes. Here, we review the latest literature on using intravital microscopy to study thrombosis as well as thromboinflammation following transient middle cerebral artery occlusion, infection-induced immunothrombosis, and liver ischemia reperfusion.

Pyruvate in organ transplantation

Pyruvate (PY) is a 3-carbon compound present in human tissues and physiologically used by cells as an energetic substrate in anaerobic conditions. In the last few years, we have successfully used PY to protect small bowel (SB), liver, and kidneys from ischemia/reperfusion injury in several experimental models. Although the mechanism of protection is not fully clarified, we have shown increased tissue levels of adenosine triphosphate (ATP) during ischemia. This suggests that providing supra-physiologic concentrations of PY during anaerobic glycolysis might enable the cells to remain viable during prolonged hypoxia. Furthermore, mechanisms such as direct inhibition of oxygen free radical formation, abrogation of neutrophilic infiltration and reduced up-regulation of adhesion molecules have also been documented in these studies. In light of these findings, we evaluated the efficacy of PY in organ preservation and transplantation. We demonstrated a protective effect on intestinal preservation injury and during acute rejection. Oral PY treatment induced immunologic changes in rejecting allograft, inhibiting perforin and granzyme-b expression and leukocytic infiltration. Protection was also documented on livers after prolonged hypothermic preservation using a PY based preservation solution. Additionally, isolated pancreatic islets were cultured in PY enriched media and maintained viable for up to 120 days followed by in vitro testing and transplantation revealing a well preserved function. All these findings suggest that PY is a potentially beneficial nutrient in patients undergoing organ transplantation and that future clinical application of PY in this field should be encouraged.