Role of nitric oxide in liver transplantation: Should it be routinely used?

Intraoperative Low-Dose Dexmedetomidine Administration Associated with Reduced Hepatic Ischemia-Reperfusion Injury in Pediatric Deceased Liver Transplantation: A Retrospective Cohort Study

Background

Dexmedetomidine (DEX) attenuates hepatic ischemia-reperfusion injury (HIRI) in adult liver transplantation (LT), but its effects on postoperative liver graft function in pediatric LT remain unclear. We sought to investigate whether intraoperative DEX administration was associated with improved liver graft function in pediatric LT recipients. It was hypothesized that DEX administration was associated with reduced HIRI and improved liver graft function.

Material/Methods

From November 2015 to May 2020, 54 deceased pediatric LT recipients were categorized into a control group and a DEX group. Intraoperatively, the DEX group received an additional infusion of DEX at 0.4 μg/kg/h from incision to the end of the operation in comparison with the control group. Preoperative, intraoperative, and postoperative data were reviewed. Postoperative liver enzyme levels and HIRI severity were assessed and compared. Independent risk factors for HIRI were determined by multivariate logistic regression analysis using a stepwise forward conditional method.

Results

We enrolled 28 and 26 patients in the DEX and control groups, respectively. Patients in the DEX group exhibited a reduced incidence of moderate-to-severe HIRI (88.5% vs 60.7%, P=0.020) and decreased level of serum alanine aminotransferase (median [interquartile range]: 407 [230–826] vs 714 [527–1492] IU/L, P=0.048) compared with the controls. Binary logistic analysis revealed that longer cold ischemia time (odds ratio [OR]=1.006; 95% confidence interval [CI]=1.000–1.013; P=0.044) and intraoperative DEX use (OR=0.198; 95% CI=0.045–0.878; P=0.033) were independent predictors for moderate-to-severe HIRI.

Conclusions

Intraoperative low-dose DEX administration was associated with a lower incidence of moderate-to-severe HIRI in pediatric deceased LT. However, further studies are needed to confirm our results and elucidate the underlying mechanisms.

Anesthesia for Combined Heart and Liver Transplantation

A heart or liver transplantation procedure performed in isolation itself presents multiple challenges for the perioperative team. Accordingly, combining both transplants yields a vastly more complicated surgery, with many unique multisystem and multidisciplinary considerations. Although combined heart and liver transplantations are being performed with increasing frequency, nationwide experience is relatively limited at most institutions. The aim of this review is to discuss the perioperative challenges presented to the anesthesiology teams and provide evidence-based guidance for the management of these daunting procedures.

Glycocalyx Preservation and NO Production in Fatty Livers-The Protective Role of High Molecular Polyethylene Glycol in Cold Ischemia Injury

Improving the protection of marginal liver grafts during static cold storage is a major hurdle to increase the donor pool of organs. The endothelium glycocalyx quality of preservation influences future inflammatory and oxidative responses. One cellular pathway responsible for the formation of nitric oxide by endothelial cells is dependent on the stimulation of proteoglycans present in the glycocalyx. We investigated the impact of the glycocalyx preservation in static cold storage of fatty liver preserved in different preservation solutions on the endothelium-mediated production of NO. Zucker fatty rat livers were preserved 24 h in static cold storage in either Institut Georges Lopez-1 (IGL-1) (n = 10), IGL-0 (i.e., without PEG35) (n = 5) or Histidine-Tryptophan-Ketoglutarate (HTK) (n = 10) preservation solutions before being processed for analysis. For Sham group (n = 5), the fatty livers were immediately analyzed after procurement. The level of transaminases and nitrites/nitrates were measured in the washing perfusate. Glycocalyx proteins expressions, Syndecan-1, glypican-1 and heparan sulfate (HS), were determined in the tissue (ELISA). Steatotic livers preserved 24 h in IGL-1 preservation solution have a significant lower level of transaminases (aspartate aminotransferase (AST), alanine aminotransferase (ALT)) and less histological damages than steatotic livers preserved 24 h with HTK (p = 0.0152). The syndecan-1 is significantly better preserved in IGL-1 group compared to HTK (p < 0.0001) and we observed the same tendency compared to IGL-0. No significant differences were observed with glypican-1. HS expression in HTK group was significantly higher compared to the three other groups. HS level in IGL-1 was even lower than IGL-0 (p = 0.0005) which was similar to Sham group. The better protection of the glycocalyx proteins in IGL-1 group was correlated with a higher production of NO than HTK (p = 0.0055) or IGL-0 (p = 0.0433). IGL-1 protective mechanisms through the formation of NO could be due to its better protective effects on the glycocalyx during SCS compared to other preservation solutions. This beneficial effect could involve the preservation state of syndecan-1 and the internalization of HS.