Multiple short-term and long-term complications might occur after liver transplantation. In the early stage after liver transplantation, the incidence of multidrug-resistant bacteria is likely to cause different types of infection, one of which is intestinal flora imbalance. In the recent decade, a series of studies have demonstrated that intestinal flora plays an important role in maintaining intestinal homeostasis. Intestinal flora may interact with other organs via multiple patterns. Among which, gut-liver axis is one of the most critical channels for regulating microenvironment of the host. Changes in the quantity and composition of intestinal flora could lead to intestinal flora imbalance. In both local and systemic systems, extensive interaction exists between intestinal flora and immune system. In this article, the risk factors of intestinal flora imbalance after liver transplantation, influence of intestinal flora imbalance on liver transplant recipients and relevant treatment strategies were reviewed.

Objective To analyze the relative indicators associated with warm ischemia time (WIT).Methods We established the porcine donor after cardiac death (DCD) model and monitored biochemical parameters (glucose,lactate,pyruvate,glycerol,and glutamate) changes of porcine livers at different WIT by microdialysis technique.The pathological changes were also observed during different WIT by HE staining.Results As the extension of WIT,the morphology injury of the graft aggravated:glucose and pyruvate levels slightly declined in the early stage,and then increased with WIT entension;glycerol levels increased with WIT entension;lactate levels and lactate/pyruvate ratio increased significantly after 20 min of WIT.The expression of lactate and lactate/pyruvate ratio were increased with the prolonged WIT.Pearson correlation analysis of all factors with liver ischemia time and liver pathological injury degree (P＜0.05) showed the obvious correlation between lactate,lactate/pyruvic acid ratio with liver ischemia time and liver pathological injury degree,and of positive correlation (P＜0.001,and correlation coefficients were 0.682 and 0.453 respectively).The ROC curve analysis revealed that the area under the curve was 0.950 for lactate,and 0.885 for pyruvate,respectively.When the critical value of lactic acid was 2.3736,the sensitivity was 90％ and specificity was 95％.When the critical value of lactate/pyruvate ratio was 0.0257,the sensitivity was 80％ and specificity was 83％.Conclusion The level of lactic acid and lactate/pyruvate ratio are significantly related to the WIT.These factors may be used as a predictor of donor liver warm ischemia injury.Reference range of these indicators needs further discussion based on larger sample research.

Objective To summarize the practice experience of establishing a stable abdominal heart transplantation model combined with tail vein injection in mice. Methods In the preliminary experiment, 50 pairs of donor and recipient Kunming mice received isotransplantation, 40 pairs of donor and recipient C57BL/6J mice underwent isotransplantation. In the formal experiment, 10 pairs of donor and recipient C57BL/6J mice received isotransplantation, 30 pairs of Balb/c mice as the donor and C57BL/6J mice as the recipient received allotransplantation. The time of each step of the heart transplantation (including harvesting and dressing of the donor heart, vascular anastomosis of the recipient, etc.) was recorded. The duration of transplanted heart beat and the survival time of the recipient was observed daily after operation. The time required for tail vein injection in the transplanted mice was recorded. Pathological examination of the transplanted heart was performed at 30 d after isotransplantation (n=5) and 7 d after allotransplantation (n=5). Results In the formal experiment, the success rate of heart transplantation was 90%. The harvesting and dressing time of donor heart was (13.9±0.6) min. The cold ischemia time of the recipient was (14.2±1.2) min. The vascular anastomosis time was (34.2±3.1) min. The total operation time was (86.6±5.4) min. Postoperatively, the transplanted heart of the mice undergoing isotransplantation survived longer than 100 d. Pathological examination at postoperative 30 d demonstrated only a slight amount of inflammatory cell infiltration. The survival time of the mice receiving allotransplantation was (7.2±0.5) d due to rejection reaction. At postoperative 7 d, pathological examination showed a large quantity of inflammatory cells infiltrating into the myocardium, manifested with acute cellular rejection. The success rate reached 90% after over 200 times of tail vein injection. Conclusions In this study, a stable mouse abdominal heart transplantation model is successfully established. The mouse models in the preliminary experiment can be utilized for tail vein injection.