The second generation of Carolina Rinse,solution II,improves graft survival following orthotopic liver transplantation in the rat by preventing reperfusion injury

Carolina Rinse solution was designed to minimize reperfusion injury following orthotopic liver transplantation. Carolina Rinse blocks reperfusion-induced endothelial cell killing, diminishes postoperative enzyme release and improves survival dramatically. Adenosine and mildly acidotic pH were identified as key components. Here we report results with a simplified formulation, Carolina Rinse H, which contains extracellular inorganic ions similar to Ringer's solution, adenosine, as well as antioxidants and radical scavengers (allopurinol, glutathione and desferrioxamine). In this study, 44 rat livers were explanted and stored for 12 h in University of Wisconsin (UW) cold storage solution (non-survival conditions). Control livers were rinsed with 15 ml cold Ringer's solution just prior to completion of implantation surgery. In this control group, average 30-day survival was poor (8%). However, survival was increased to around 60% when grafts were rinsed with Carolina Rinse II. Survival was not improved significantly by rinsing the graft with Ringer's solution containing antioxidants and radical scavengers with adenosine omitted (about 30%). Peak SGOT values of nearly 3000 U/l, measured 1–3 days postoperatively in the Ringer's rinse control group, were decreased 4- to 5-fold both by Carolina Rinse II and by Ringer's solution containing antioxidants. On the other hand, the addition of adenosine to Ringer's solution improved survival (around 60%) but did not decrease the postoperative elevation of serum enzymes significantly. Thus, it appears that adenosine was necessary for optimal survival whereas antioxidants and radical scavengers were needed to prevent injury to the transplanted graft. These data were consistent with the hypothesis that at least two mechanisms, one involving the liver and a second one non-hepatic, are responsible for post-transplant patho-physiology. Carolina Rinse II also reduced the postoperative elevation in serum enzymes 2- to 3-fold in livers stored under survival conditions (e. g., for 8 h in UW solution). This study demonstrated convincingly that a very simple rinse solution, Carolina Rinse II, improved survival significantly and minimized graft injury following orthotopic liver transplantation.     

Warm Carolina rinse solution prevents graft failure from storage injury after orthotopic rat liver transplantation with arterialization

An injury to nonparenchymal cells, characterized by loss of viability of sinusoidal endothelial cells and activation of Kupffer cells, occurs after reperfusion of livers stored for transplantation. Recently, a new solution, Carolina rinse solution, was shown to prevent reperfusion injury to endothelial cells in vitro almost completely and to improve graft survival after orthotopic rat liver transplantation (ORLT) without arterialization. ORLT with arterialization permits longer cold storage of donor livers and more closely models human surgery. Therefore, we evaluated the effects of Carolina rinse solution on graft survival after ORLT with arterialization in syngeneic Lewis rats. Just prior to implantation, donor livers stored in University of Wisconsin (UW) solution were rinsed with 30 ml of Ringer's solution, saline, or Carolina rinse solution at 1°–4°C. In livers stored for 15 h and rinsed with Ringer's or saline solution, long-term graft survival was only 8%. Using Carolina rinse solution containing 1 mmol and 200 mol adenosine per liter, graft survival improved to 40% and 80%, respectively. Graft survival did not improve when using Carolina rinse solution with adenosine omitted or Ringer's solution containing 200 mol adenosine per liter. Livers were also rinsed with Carolina rinse solution containing 200 mol adenosine per liter at 28°–30°C rather than at 1°–4°C. With warm Carolina rinse solution, survival improved further to 100%, 80%, and 50% after 15, 18, and 21 h of storage. After 18 h of storage, light and electron microscopy demonstrated marked denudation of the sinusoidal lining and activation of Kupffer cells in grafts rinsed with Ringer's solution. Use of Carolina rinse solution greatly improved endothelial structure but did not reduce Kupffer cell activation. In conclusion, these findings show that Carolina rinse solution substantially improves graft survival after ORLT with arterialization. Adenosine and warm temperature are important factors contributing to efficacy. A mechanism of protection appears to be prevention of reperfusion-induced endothelial cell injury.     

Effects of warm Carolina rinse on microvascular reperfusion injury in rat liver transplantation

Abstract Recently, it has been demonstrated that the use of both cold Carolina rinse (CR, 4°C) as well as warm Ringer's lactate (RL, 37°C) attenuates microvascular perfusion failure and leukocyte (WBC) accumulation in liver grafts. The aim of this study was to analyse in vivo whether warming of CR can also lead to a reduction in microvascular reperfusion injury in rat liver transplantation. Syngeneic orthotopic liver transplantation, including arterial reconstruction, was performed in male Lewis rats (180–300 g). Livers were stored in University of Wisconsin (UW) solution for 24 h and rinsed with 15 ml CR which was either cold 4 °C ( n = 7) or warm 37 °C ( n = 8) prior to reperfusion. Hepatic microcirculation and WBC accumulation were assessed by intra-vital fluorescence microscopy, and graft function was determined by analysis of bile flow during the 90-min reperfusion period. Warm CR yielded significantly ( P < 0.01) improved sinusoidal perfusion when compared with cold CR; however, the extent of WBC adherence in both sinusoids and postsinusoidal venules did not vary between the groups. In addition, bile flow was slightly increased after warm CR. We conclude that after 24 h of cold storage in UW solution, warming of CR may offer additional benefit in the prevention of microcirculatory reperfusion injury without affecting WBC accumulation.     

Reperfusion injury to endothelial cells after cold storage of rat livers: protection by mildly acidic pH and lack of protection by antioxidants

Lethal reperfusion injury to sinusoidal endothelial cells occurs after cold ischemic storage of livers and may be responsible for liver graft failure from storage injury. Here, we evaluated potential mechanisms underlying this reperfusion injury. In rat livers stored in Euro-Collins solution for 24 h and reperfused with Krebs-Henseleit bicarbonate buffer, nonparenchymal cell killing showed periportal predominance as assessed by nuclear staining with trypan blue. In livers reperfused in the retrograde direction, the lobular distribution of cell killing was reversed, indicating that cell killing was more rapid in oxygenrich upstream regions. However, antioxidants, including allopurinol, desferrioxamine, catalase, superoxide dismutase, superoxide dismutase plus catalase, and U74006F, did not reduce cell killing. Similarly, reperfusion with anoxic buffer did not prevent lethal injury. Antioxidants and anoxic reperfusion also did not improve cell viability in livers stored in UW solution. Nevertheless, superoxide generation, as identified by formazan formation from nitroblue tetrazolium, was increased in Kupffer cells after lives storage and reperfusion as compared to unstored livers. Acidification of the reperfusion buffer from pH 7.4 to pH 7.15 reduced overall nonparenchymal cell killing from about 40% to 10%. Moreover, a pH gradient developed across the liver lobule during reperfusion with the effluent 0.2–0.4 pH units more acidic than the influent. This intralobular pH gradient appears to account for the relative sparing of cells in more acidic downstream regions of the lobule. Lower temperatures of reperfusion also reduced lethal injury. In conclusion, Kupffer cells generated superoxide after perfusion of stored rat livers, but formation of oxygen free radicals did not appear to contribute to lethal reperfusion injury to endothelial cells. Rather, mildly acidotic pH was protective against lethal injury. Thus, hydrogen ion concentration may be a critical determinant of reperfusion injury to sinusoidal endothelial cells.     

小鼠肝动脉重建对长时间冷保存移植肝存活率的影响

研究小鼠肝动脉重建(hepatic arterial reconstruction,HAR)对长时间冷保存移植肝存活率的影响.方法 同系雄性C57BL/6小鼠68只,分为冷保存时间(cold preservation time,CPT) 1 h组、CPT 4 h组、CPT 8 h组、CPT 16 h组、CPT 16 h+HAR组(供、受体小鼠各一半).小鼠供肝经门静脉灌注4℃ UW液后保存.肝脏移植采用缝合法(肝上下腔静脉)和袖套法 (门静脉、肝下下腔静脉) 吻合,胆管采用内支架管重建法.小鼠HAR采用含供体肝动脉的腹主动脉与受体腹主动脉端侧吻合的方法.观察术后5组受体小鼠移植肝的存活时间,用组织学检查肝细胞损伤情况,用免疫组织化学法观察肝细胞再生功能.结果 CPT 1 h、4 h、8 h组受体术后12 d移植物的存活率分别为7/7、10/10、9/9.CPT 16 h组除1例小鼠存活外,其余均在移植术后36 h内死亡,存活率为10%(1/10),CPT 16 h+HAR组受体90%(9/10)存活,两组存活率相比,差异有统计学意义(P<0.01).CPT 1 h、4 h组的移植物组织损伤程度轻,CPT 8 h 组的移植物组织损伤程度较前两组严重,但肝细胞再生活跃.CRT 16 h组的移植肝组织表现为广泛肝细胞空泡变性、坏死,肝细胞再生不明显.CPT 16 h+HAR组仅有轻度的肝窦淤血,肝细胞空泡变性、坏死改变,肝细胞再生活跃.结论 HAR可提高长时间冷保存移植肝的存活率.     

Improved microcirculation by low‐viscosity histidine– tryptophan–ketoglutarate graft flush and subsequent cold storage in University of Wisconsin solution: results of an orthotopic rat liver transplantation model

As previously shown in a model of isolated rat liver perfusion, the combined use of an initial graft flush with low‐viscosity histidine–tryptophan–ketoglutarate (HTK) solution followed by cold storage in University of Wisconsin (UW) solution markedly improved the preservation during an extended cold storage period. In this study, we aimed to transfer our results into an in vivo model of orthotopic rat liver transplantation, and to elucidate the potential mechanism of the improved preservation by focusing on the hepatic microcirculation. Livers were harvested from male Wistar rats. Aortic perfusion with a pressure of 100 cm H₂O was performed with either UW (group UW) or HTK (groups UW and HTK_UW), followed by additional back‐table perfusion with UW (group HTK_UW). After 20‐h cold storage at 4 °C, livers were orthotopically transplanted with reconstructing the hepatic artery. As measured by bile flow and liver enzymes, HTK flush followed by UW storage was superior compared to single use of either UW or HTK solution. The hepatic microcirculation was significantly improved, as shown by the increased percentage of reperfused sinusoids and reduced sinusoidal leucostasis. HTK and UW effectively reduce ischaemia‐reperfusion injury after liver transplantation. By combining the comparative advantages of both solutions, a cumulative effect resulting in an improved preservation was shown. Thus, this mechanism improves microcirculatory reperfusion.