Perioperative cytokines during orthotopic liver transplantation without venovenous bypass

The effects of venovenous bypass use in liver transplantation with piggyback technique: a propensity score-weighted analysis

Venovenous bypass (VVB) use during liver transplantation (LT) is notably variable among the centres and it is actually restricted to surgically complex cases, severely unstable recipients or grafts from high-risk donors. Historically, VVB was associated with the classical LT with caval cross clamping, while not much is known about the safety of this technique applied to piggyback LT. This retrospective observational study evaluated the effects of VVB applied to piggyback LT on mortality, hospital outcomes, postoperative graft and other organ dysfunction. We retrospectively collected data about recipient status, surgical complexity and graft quality of all the piggyback LTs performed at the Transplant Unit of IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy, from January 2012 to December 2022. A propensity score (PS) was built taking into account the variables possibly associated with either VVB choice and the investigated outcomes with the average treatment overlap method. PS-weighted general linear models (GLMs) were developed to investigate the adjusted effect of VVB use on the selected outcomes. The final analysis included 874 LT cases, of whom 74 (8.5%) underwent VVB. The effective sample sizes after PS-weighting were 280.2 and 64.3 patients in the no-VVB and VVB groups, respectively. PS-weighted GLMs did not show any differences regarding hospital and graft-related outcomes. However, significantly higher odds ratios for serum creatinine > 2 mg/dL and AKIN stage 2 or 3 during the first 24 h after ICU admission together with a higher renal replacement therapy need during ICU stay were reported for VVB exposure in the weighted analyses. This study suggests similar mortality and length of stay but a higher risk for postoperative acute kidney injury in patients undergoing piggyback LT with VVB.

Pathophysiologic Implications of Cytokines Secretion during Liver Transplantation Surgery

We introduce the following issues of the cytokines secretion during liver transplantation surgery in this review article; 1) the aspect of cytokines secretion during liver transplantation surgery, 2) the evidences of association of cytokines concentration with post-transplantation graft survival, 3) a variety of factors that may influence the secretion of cytokines during liver transplantation, 4) pro-inflammatory and anti-inflammatory cytokine balance during the surgery, and 5) the issues of T helper 1 and T helper 2, and T helper 17 and regulatory T cell signature cytokines secretion and their ratio during liver transplantation surgery. Primary failure of the liver is associated with the secondary dysfunction of virtually all other organ systems, including the cardiovascular, pulmonary, renal, coagulation and central nervous systems. In addition, liver transplantation surgery itself is a major surgical procedure with accompanying life-threatening hemorrhage, massive transfusion, clamping and unclamping of great vessels and resulting ischemia-reperfusion injury and cardiovascular instability. Both the underlying liver failure and the surgical events act as stressors and promote the secretion of various cytokines. So it is clinically important to understand above issues regarding the cytokines secretion during liver transplantation surgery. As cytokines secretion has clear relationship with post-transplantation clinical outcomes, future study directions for artificially manipulating cytokines secretion is also suggested for enhancing outcomes of the patients.

Inferior graft survival of hepatitis B core positive grafts is not influenced by post-transplant hepatitis B infection in liver recipients--5-year single-center experience

Nonoptimal liver grafts, and among them organs from anti-HBc+ donors, are increasingly used for liver transplantation. In this retrospective study including 1065 adult liver transplantations performed between 1977 and 2012, we analyzed long-term patient and graft survival and occurrence of HBV infection. A total of 52 (5.1%) patients received an anti-HBc+ graft. The 10-year graft and patient survival of these recipients were 50.9% and 59.0% compared to 72.0% and 76.5% (P = 0.001; P = 0.004) of patients receiving anti-HBc- grafts, respectively. Cox regression model showed that high urgency allocation (P = 0.003), recipient age (P = 0.027), anti-HCV+ recipients (P = 0.005), and anti-HBc+ organs (P = 0.048) are associated with decreased graft survival. Thirteen of 52 (25.0%) patients receiving anti-HBc+ grafts developed post-transplant HBV infection within a mean of 2.8 years. In this study, antiviral prophylaxis did not have significant impact on HBV infection, but long-term survival (P = 0.008). Development of post-transplant HBV infection did not affect adjusted 10-year graft survival (100% vs. 100%; P = 1). Anti-HBc+ liver grafts can be transplanted with reasonable but inferior long-term patient and graft survival. The inferior graft survival is not, however, related with post-transplant HBV infection as long as early diagnosis and treatment take place.

Alterations of Endothelial Glycocalyx During Orthotopic Liver Transplantation in Patients With End-Stage Liver Disease

BACKGROUND

Endothelial glycocalyx participates in the maintenance of vascular integrity, and its perturbations cause capillary leakage, loss of vascular responsiveness, and enhanced adhesion of leukocytes and platelets. We hypothesized that marked shedding of the glycocalyx core protein, syndecan-1, occurs in end-stage liver disease (ESLD) and that it increases during orthotopic liver transplantation (OLT). We further evaluated the effects of general anesthesia on glycocalyx shedding and its association with acute kidney injury (AKI) after OLT.

PATIENTS AND METHODS

Thirty consecutive liver transplant recipients were enrolled in this prospective study. Ten healthy volunteers served as a control. Acute kidney injury was defined by Acute Kidney Injury Network criteria.

RESULTS

Plasma syndecan-1 was significantly higher in ESLD patients than in healthy volunteers (74.3 ± 59.9 vs 10.7 ± 9.4 ng/mL), and it further increased significantly after reperfusion (74.3 ± 59.9 vs 312.6 ± 114.8 ng/mL). The type of general anesthesia had no significant effect on syndecan-1. Syndecan-1 was significantly higher during the entire study in patients with posttransplant AKI stage 2 or 3 compared to patients with AKI stage 0 or 1. The area under the curve of the receiver operating characteristics curve of syndecane-1 to predict AKI stage 2 or 3 within 48 hours after reperfusion was 0.76 (95% confidence interval, 0.57-0.89, P = 0.005).

CONCLUSIONS

Patients with ESLD suffer from glycocalyx alterations, and ischemia-reperfusion injury during OLT further exacerbates its damage. Despite a higher incidence of AKI in patients with elevated syndecan-1, it is not helpful to predict de novo AKI. Volatile anesthetics did not attenuate glycocalyx shedding in human OLT.

Cytokine response to ischemia/reperfusion injury in an ex vivo perfused porcine liver model

BACKGROUND

We evaluated the degree of inflammatory response after ischemia/reperfusion injury by an extracorporeal normothermic autologous hemoperfusion of porcine livers.

MATERIALS AND METHODS

Livers explanted from 7 pigs were perfused extracorporeally at 39 degrees C with autologous blood. Serum samples were obtained hourly until 6 hours from the beginning of reperfusion and assayed for 9 different cytokines.

RESULTS

Significant elevations in interleukin 6 (IL-6) and IL-8 were noted following reperfusion (P < .001), with both demonstrating an increase which followed a sigmoid curve; other cytokines that were assessed showed no significant change.

CONCLUSIONS

The ex vivo model excludes the liver from the influence of external systemic factors such as hormones, the autonomic nervous system, and other regulatory molecules produced elsewhere in the body, allowing the response to the ischemia/reperfusion injury to be studied in isolation and in considerable detail. Although this study examined a relatively short period, the increases in only IL-6 and IL-8 suggested that these are important molecules in the early phase after reperfusion.

Factors influencing the concentration of cytokines during liver transplantation

Not only does the underlying disease that requires surgery constitute a significant stress to the human body, but also the surgery itself serves as a stressor. Cytokine secretion is activated in response to the surgical stress during liver transplantation. We examined 44 patients to compare cytokine levels, according to the underlying diseases causing liver failure (viral hepatitis vs alcoholic hepatitis), examining whether the values differed according to the model for end-stage liver disease (MELD) score [high (≥20) vs low (<20)]. Pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)1β, and IL-6 and anti-inflammatory cytokines IL-4 and IL-10 were quantified using sandwich enzyme- linked immunoassays at three times: (1) after inducing anesthesia, (2) 60 minutes after the start of the anhepatic period, and (3) 60 minutes after reperfusion. No difference in the level of any cytokine measured in our study was detected at any time point between the viral and the alcoholic hepatitis groups. Among the high MELD group, IL-1β and IL-4 contents were higher than in the low MELD group at all time points (P < .05). IL-10 concentrations at time 1 and TNF-α at time 2 were higher among the high MELD group (P < .05). In conclusion, the severity of the inflammatory and stress reactions expressed as cytokine concentrations did not differ according to the underlying liver disease, but did associate with the MELD score.

Association of IL-6 promoter and IFN-γ gene polymorphisms with acute rejection of liver transplantation

Liver transplantation is one of the most important therapies for end-stage liver diseases and is associated with major problems including infections and acute rejection. The outcome of transplantation can be determined by immune responses as a key role in response to the graft. Inflammatory and anti-inflammatory mediators especially cytokines influence the graft microenvironment. Th1 and Th2 immune responses in contrast to regulatory responses cause acute rejection or help graft survival. In this study, we evaluated the gene polymorphisms of IL-6 G-174C, TGF-β T + 869C, IL-4 C-590T, and IFN-γ T + 874A cytokines in liver transplant patients. ARMS-PCR method was used to characterize IL-6 G-174C, TGF-β T + 869C and IFN-γ T + 874A polymorphisms and PCR-RFLP using AvaII restriction enzyme was done for IL-4 C-590T characterization in 70 liver transplant patients. Acute rejection episodes were diagnosed according to standard criteria. The analysis of the results showed that IL-6-174 GG genotype ( P = 0.009, OR = 4.333, 95% CI = 1.043-18.000), IL-6-174G allele (P = 0.011, OR = 5.273, 95% CI = 1.454-19.127) was more frequent and IFN-γ +874 TT genotype was less frequent (P = 0.043, OR = 0.143, 95% CI = 0.0118-1.190) in acute rejection than in non-rejection patients. TGF-β T + 869C and IL-4 C-590T frequencies were not significantly different (P > 0.05). According to the results, it can be conclude that IL-6 G-174C and IFN-γ T + 874A gene polymorphisms have predictive values for acute rejection after liver transplantation. High producer genotype of IL-6 is a genetic risk factor and IFN-γ is a protective factor for acute rejection development.

The clinical relevance of the anhepatic phase during liver transplantation

This study assesses the relation between the anhepatic phase duration and the outcome after liver transplantation. Of 645 patients who underwent transplantation between 1994 and 2006, 194 were recipients of consecutive adult primary piggyback liver transplants using heart-beating donors. The anhepatic phase was defined as the time from the physical removal of the liver from the recipient to recirculation of the graft. Other noted study variables were the cold and warm ischemia times, donor and recipient age, donor and recipient body mass index, perioperative red blood cell (RBC) transfusion, indication for transplantation, and Model for End-Stage Liver Disease score. The primary outcome parameter was graft dysfunction, which was defined as either primary nonfunction or initial poor function according to the Ploeg-Maring criteria. The median anhepatic phase was 71 minutes (37-321 minutes). Graft dysfunction occurred in 27 patients (14%). Logistic regression analysis showed an anhepatic phase over 100 minutes [odds ratio (OR), 4.28], a recipient body mass index over 25 kg/m(2) (OR, 3.21), and perioperative RBC transfusion (OR, 3.04) to be independently significant predictive factors for graft dysfunction. One-year patient survival in patients with graft dysfunction was 67% versus 92% in patients without graft dysfunction (P < 0.001). A direct relation between the anhepatic phase duration and patient survival could, however, not be established. In conclusion, this study shows that liver transplant patients with an anhepatic phase over 100 minutes have a higher incidence of graft dysfunction. Patients with graft dysfunction have significantly worse 1-year patient survival.