Effect of cold-ischemia time on nuclear factor-κB activation and inflammatory response in graft after orthotopic liver transplantation in rats

Risk factors for postreperfusion syndrome during living donor liver transplantation in paediatric patients with biliary atresia: a retrospective analysis

BACKGROUND

Living donor liver transplantation (LT) is the main treatment for paediatric biliary atresia (BA) in Asia. During LT, a series of haemodynamic changes often occur during LT reperfusion, which is called postreperfusion syndrome (PRS), and PRS is related to a prolonged postoperative hospital stay, delayed recovery of graft function and increased mortality. To reduce adverse reactions after paediatric living donor LT (LDLT), our study's objectives were to ascertain the incidence of PRS and analyse possible risk factors for PRS.

METHODS

With the approval of the Ethics Committee of our hospital, the clinical data of 304 paediatric patients who underwent LDLT from January 2020 to December 2021 were analysed retrospectively. According to the presence or absence of PRS, the paediatric patients were divided into the non-PRS group and the PRS group. Independent risk factors of PRS were analysed using logistic regression analysis.

RESULTS

PRS occurred in 132 recipients (43.4%). The peak values of AST (816 (507-1625) vs 678 (449-1107), p=0.016) and ALT (675 (415-1402) vs 545 (389-885), p=0.015) during the first 5 days after LDLT in paediatric patients with PRS were significantly higher than those in the non-PRS group. Meanwhile, the paediatric patients in the PRS group had longer intensive care unit stays and hospital stays, as well as lower 1-year survival rates. Graft cold ischaemic time (CIT) ≥90 min (OR (95% CI)=5.205 (3.094 to 8.754)) and a temperature <36°C immediately before reperfusion (OR (95% CI)=2.973 (1.669 to 5.295)) are independent risk factors for PRS.

CONCLUSIONS

The occurrence of hypothermia (<36.0℃) in children immediately before reperfusion and graft CIT≥90 min are independent risk factors for PRS. PRS was closely related to the postoperative adverse outcomes of paediatric patients.

Role of Fractalkine-CX3CR1 Axis in Acute Rejection of Mouse Heart Allografts Subjected to Ischemia Reperfusion Injury

Transplantation outcomes are affected by the increase in rejection associated with ischemia reperfusion injury (IRI). Fractalkine (FKN), a chemokine for recruitment of CX3CR1⁺ leukocytes, contributes to the pathogenesis of various inflammatory diseases. Herein, we evaluated the importance of the FKN-CX3CR1 axis during IRI-related rejections using a mouse heterotopic heart transplantation model. FKN expression and graft survival was compared between wild-type C57BL/6 recipients transplanted with BALB/c hearts preserved for 8 (WT-IRI) and 0.5 h (WT-control) at 4°C. Graft survival of WT-IRI was shorter than that of WT-control. FKN was expressed on the vascular endothelium in WT-IRI allografts, but minimally in WT-control. The role of the FKN-CX3CR1 axis in IRI-related rejection was directly investigated using the transplant model with CX3CR1-deficient recipients (CX3CR1 KO-IRI) or treatment with anti-mouse FKN monoclonal antibodies. Graft survival of CX3CR1 KO-IRI was longer than that of WT-IRI; antibody treatment prolonged graft survival. The contribution of CX3CR1⁺ monocytes to IRI-related rejection was evaluated by adoptive transfer to CX3CR1 KO-IRI. Adoptive transfer of CX3CR1⁺ monocytes attenuated the effect of prolonged graft survival in CX3CR1 KO-IRI. Overall, the FKN-CX3CR1 axis plays a major role during IRI-related rejection; its blockade has the potential to improve the outcomes of deceased donor transplantation.

Post reperfusion syndrome during liver transplantation: From pathophysiology to therapy and preventive strategies

This review aims at evaluating the existing evidence regarding post reperfusion syndrome, providing a description of the pathophysiologic mechanisms involved and possible management and preventive strategies. A PubMed search was conducted using the MeSH database, “Reperfusion” AND “liver transplantation” were the combined MeSH headings; EMBASE and the Cochrane library were also searched using the same terms. 52 relevant studies and one ongoing trial were found. The concept of post reperfusion syndrome has evolved through years to a multisystemic disorder. The implications of the main organ, recipient and procedure related factors in the genesis of this complex syndrome are discussed in the text as the novel pharmacologic and technical approaches to reduce its incidence. However the available evidence about risk factors, physiopathology and preventive measures is still confusing, the presence of two main definitions and the numerosity of possible confounding factors greatly complicates the interpretation of the studies.

Postreperfusion syndrome during liver transplantation

As surgical and graft preservation techniques have improved and immunosuppressive drugs have advanced, liver transplantation (LT) is now considered the gold standard for treating patients with end-stage liver disease worldwide. However, despite the improved survival following LT, severe hemodynamic disturbances during LT remain a serious issue for the anesthesiologist. The greatest hemodynamic disturbance is postreperfusion syndrome (PRS), which occurs at reperfusion of the donated liver after unclamping of the portal vein. PRS is characterized by marked decreases in mean arterial pressure and systemic vascular resistance, and moderate increases in pulmonary arterial pressure and central venous pressure. The underlying pathophysiological mechanisms of PRS are complex. Moreover, risk factors associated with PRS are not fully understood. Rapid and appropriate treatment with vasopressors, volume replacement, or venesection must be provided depending on the cause of the hemodynamic disturbance when hemodynamic instability becomes profound after reperfusion. The negative effects of PRS on postoperative early morbidity and mortality are clear, but the effect of PRS on postoperative long-term mortality remains a matter of debate.

Postreperfusion syndrome during liver transplantation for cirrhosis: outcome and predictors

During orthotopic liver transplantation (OLT), a marked decrease in blood pressure following unclamping of the portal vein and liver reperfusion is frequently observed and is termed postreperfusion syndrome (PRS). The predictive factors and clinical consequences of PRS are not fully understood. The goal of this study was to identify predictors of PRS and morbidity/mortality associated with its occurrence during OLT in patients with cirrhosis. During a 3-year period, all consecutive OLT procedures performed in patients with cirrhosis were studied. Exclusion criteria were OLT for acute liver failure, early retransplantation, combined liver/kidney transplantation, and living-donor related transplantation. PRS was defined as a decrease in the mean arterial pressure of more than 30% of the value observed in the anhepatic stage, for more than 1 minute during the first 5 minutes after reperfusion of the graft. Transplantation was performed with preservation of the inferior vena cava with or without temporary portocaval shunt. Associations between PRS and donor and recipient demographic data, recipient operative and postoperative outcomes were tested with bivariate statistics. Independent predictors of PRS were determined in multivariable logistic regression analysis. Of the 75 patients included in the study, 20 patients (25%) developed PRS. In a multivariable analysis, absence of a portocaval shunt [odds ratio (95% confidence interval) = 4.42 (1.18-17.6)] and duration of cold ischemia [odds ratio (95% confidence interval) = 1.34 (1.07-1.72)] were independent predictors of PRS. Patients who experienced PRS displayed more postoperative renal failure and lower early (<15 days after OLT) survival (80% versus 96%; P = 0.04). In conclusion, the absence of portocaval shunt and the duration of cold ischemia were independent predictors of intraoperative PRS. PRS was associated with significant adverse postoperative outcome. These results provide realistic clinical targets to improve patient outcome after OLT for cirrhosis.

Role of NF-kappaB as effector of IPC in donor livers before liver transplantation in rats

The objective of this study was to investigate the effect of ischemic preconditioning (IPC) on NF-kappaB activity during reperfusion early after liver transplantation in rats.

METHODS

Male Sprague-Dawley (SD) rats were used as donors and recipients of orthotopic liver transplantations. The donor liver was stored 2 hours in Ringer's solution at 4 degrees C preimplantation. IPC was performed by clamping of the portal vein and hepatic artery of the donor for 10 minutes followed by reperfusion for 10 minutes before harvesting. At 1, 2, 4, and 6 hours after portal vein reperfusion, graft samples were obtained to determine hepatic levels of NF-kappaB activity, tumor necrosis factor (TNF)-alpha and intercellular adhesion molecule (ICAM)-1. Blood samples were obtained to measure serum alanine aminotransferase (ALT) and lactate dehydrogenase (LDH).

RESULTS

After liver transplantation without IPC, serum levels of ALT and LDH increased significantly compared with the sham-operated group. Among the IPC group, serum ALT and LDH decreased significantly. NF-kappaB activity in the graft increased within 6 hours after transplantation. Among the IPC group, NF-kappaB activity was significantly attenuated. Hepatic levels of TNF-alpha and ICAM-1 were significantly elevated in the non-IP group but both were reduced in the IPC group.

CONCLUSION

IPC downregulated TNF-alpha and ICAM-1 expression in the graft, most likely through decreased NF-kappaB activation, and attenuated neutrophil infiltration after reperfusion.