Hyperbaric oxygen therapy reduces the severity of ischaemia, preservation and reperfusion injury in a rat model of liver transplantation

Hemoglobin-Based Oxygen Carriers: Potential Applications in Solid Organ Preservation

Ameliorating graft injury induced by ischemia and hypoxia, expanding the donor pool, and improving graft quality and recipient prognosis are still goals pursued by the transplant community. The preservation of organs during this process from donor to recipient is critical to the prognosis of both the graft and the recipient. At present, static cold storage, which is most widely used in clinical practice, not only reduces cell metabolism and oxygen demand through low temperature but also prevents cell edema and resists apoptosis through the application of traditional preservation solutions, but these do not improve hypoxia and increase oxygenation of the donor organ. In recent years, improving the ischemia and hypoxia of grafts during preservation and repairing the quality of marginal donor organs have been of great concern. Hemoglobin-based oxygen carriers (HBOCs) are “made of” natural hemoglobins that were originally developed as blood substitutes but have been extended to a variety of hypoxic clinical situations due to their ability to release oxygen. Compared with traditional preservation protocols, the addition of HBOCs to traditional preservation protocols provides more oxygen to organs to meet their energy metabolic needs, prolong preservation time, reduce ischemia–reperfusion injury to grafts, improve graft quality, and even increase the number of transplantable donors. The focus of the present study was to review the potential applications of HBOCs in solid organ preservation and provide new approaches to understanding the mechanism of the promising strategies for organ preservation.

Influence of intraoperative oxygen content on early postoperative graft dysfunction in living donor liver transplantation: A STROBE-compliant retrospective observational study

The aim of the present study was to investigate the role of intraoperative oxygen content on the development of early allograft dysfunction (EAD) in patients undergoing living donor liver transplantation (LDLT).This retrospective review included 452 adult patients who underwent elective LDLT. Our study population was classified into 2 groups: EAD and non-EAD. Arterial blood gas analysis was routinely performed 3 times during surgery: during the preanhepatic phase (ie, immediately after anesthetic induction); during the anhepatic phase (ie, at the onset of hepatic venous anastomosis); and during the neohepatic phase (ie, 1 hour after graft reperfusion). Arterial oxygen content (milliliters per deciliters) was derived using the following equation: (1.34 × hemoglobin [gram per deciliters] × SaO2 [%] × 0.01) + (0.0031 × PaO2 [mmHg]).The incidence of EAD occurrence was 13.1% (n = 59). Although oxygen contents at the preanhepatic phase were comparable between the 2 groups, the oxygen contents at the anhepatic and neohepatic phases were lower in the EAD group than in the non-EAD group. Patients with postoperative EAD had lower oxygen content immediately before and continuously after graft reperfusion, compared to patients without postoperative EAD. After the preanhepatic phase, oxygen content decreased in the EAD group but increased in the non-EAD group. The oxygen content and prevalence of normal oxygen content gradually increased during surgery in the non-EAD group, but not in the EAD group. Multivariable analysis revealed that oxygen content during the anhepatic phase and higher preoperative CRP levels were factors independently associated with the occurrence of EAD (area under the receiver-operating characteristic curve: 0.754; 95% confidence interval: 0.681-0.826; P < .001 in the model). Postoperatively, patients with EAD had a longer duration of hospitalization, higher incidences of acute kidney injury and infection, and experienced higher rates of patient mortality, compared to patients without EAD.Lower arterial oxygen concentration may negatively impact the functional recovery of the graft after LDLT, despite preserved hepatic vascular flow. Before graft reperfusion, the levels of oxygen content components, such as hemoglobin content, PaO2, and SaO2, should be regularly assessed and carefully maintained to ensure proper oxygen delivery into transplanted liver grafts.

Hyperbaric Oxygen Therapy in Liver Diseases

Hyperbaric oxygen therapy (HBOT) is an efficient therapeutic option to improve progress of lots of diseases especially hypoxia-related injuries, and has been clinically established as a wide-used therapy for patients with carbon monoxide poisoning, decompression sickness, arterial gas embolism, problematic wound, and so on. In the liver, most studies positively evaluated HBOT as a potential therapeutic option for liver transplantation, acute liver injury, nonalcoholic steatohepatitis, fibrosis and cancer, especially for hepatic artery thrombosis. This might mainly attribute to the anti-oxidation and anti-inflammation of HBOT. However, some controversies are existed, possibly due to hyperbaric oxygen toxicity. This review summarizes the current understandings of the role of HBOT in liver diseases and hepatic regeneration. Future understanding of HBOT in clinical trials and its in-depth mechanisms may contribute to the development of this novel adjuvant strategy for clinical therapy of liver diseases.

Application of hyperbaric oxygen in liver transplantation

In recent years, hyperbaric oxygen (HBO) has been used in the treatment of a lot of diseases such as decompression sickness, arterial gas embolism, carbon dioxide poisoning, soft tissue infection, refractory osteomyelitis, and problematic wound, but little is known about its application in liver transplantation. Although several studies have been conducted to investigate the protective effects of HBO on liver transplantation and liver preservation, there are still some controversies on this issue, especially its immunomodulatory effect. In this short review, we briefly summarize the findings supporting the application of HBO during liver transplantation (including donors and recipients).

Key Points in Establishing a Model of Mouse Liver Transplantation

The explosion of interest in research into the mouse genome and immune system has meant that the mouse orthotopic liver transplantation (MOLT) model has become a popular means of studying transplantation immunity, organ preservation, ischemia-reperfusion injury, and surgical techniques, among others. Although numerous modifications and refinements of surgical techniques have simplified the operation, the relatively short duration of postoperative survival after MOLT remains an obstacle to longer-term follow-up studies. Here, we summarize the scientific basis of MOLT and our experience improving and refining the model in six key areas: anesthesia, operative technique, perfusion and preservation of the liver, cuff technique, anhepatic time, and the value of rearterialization for the liver graft. We also compare the characteristics of different surgical techniques, and give recommendations for the best means of tailoring technique to the objectives of a study. In doing so, we aim to assist other investigators in establishing and perfecting the MOLT model in their routine research practice.

Successful treatment for sorafenib-induced liver dysfunction: a report of case with liver biopsy

Sorafenib is an oral multikinase inhibitor with anti-proliferative and anti-angiogenic effects and is used worldwide for the treatment of advanced or metastatic hepatocellular carcinoma (HCC). While the significant survival benefit of sorafenib in patients with advanced HCC was demonstrated, various treatment-related adverse events might happen. Of them, the incidence of drug-related severe liver dysfunction rarely occurs (<1 %) but is one of the serious adverse events by sorafenib. The authors highlight the case of a 71-year-old man with metastatic HCC with sorafenib-related fatal liver dysfunction (T-Bil 28.6 mg/dL, AST 1611 IU/L, ALT 1098 IU/L) 2 months later even without either intrahepatic viable HCC or hepatitis B virus (HBV) reactivation. Then, the liver dysfunction was improved following aggressive treatment using hyperbaric oxygen. A liver biopsy demonstrated cholestasis, degeneration, and necrosis in hepatocytes with lymphocyte infiltration. Thus, sorafenib rarely can induce liver dysfunction characterized by cholestatic and hepatocellular injury types, and it could be a fatal event. Clinicians should pay attention to any increase in the liver enzymes in these patients.

Hyperbaric oxygen therapy reduces the severity of ischaemia, preservation and reperfusion injury in a rat model of liver transplantation

BACKGROUND

  Approaches to increase organ availability for orthotopic liver transplantation (OLT) often result in the procurement of marginal livers that are more susceptible to ischaemia, preservation and reperfusion injury (IPRI).

METHODS

  The effects of post-OLT hyperbaric oxygen (HBO) therapy on IPRI in a syngeneic rat OLT model were examined at various time-points. The effects of IPRI and HBO on hepatocyte necrosis, apoptosis, proliferation, and sinusoidal morphology and ultrastructure were assessed.

RESULTS

  Post-OLT HBO therapy significantly reduced the severity of IPRI; both apoptosis [at 12 h: 6.4 ± 0.4% in controls vs. 1.6 ± 0.7% in the HBO treatment group (p < 0.001); at 48 h: 2.4 ± 0.2% in controls vs. 0.4 ± 0.1% in the HBO treatment group (p < 0.001)] and necrosis [at 12 h: 18.7 ± 1.8% in controls vs. 2.4 ± 0.4% in the HBO treatment group (p < 0.001); at 48 h: 8.5 ± 1.3% in controls vs. 3.4 ± 0.9% in the HBO treatment group (P= 0.019)] were decreased. Serum alanine transaminase was reduced [at 12 h: 1068 ± 920 IU/l in controls vs. 370 ± 63 IU/l in the HBO treatment group (P= 0.030); at 48 h: 573 ± 261 IU/l in controls vs. 160 ± 10 IU/l in the HBO treatment group (P= 0.029)]. Treatment with HBO also promoted liver regeneration [proliferation at 12 h: 4.5 ± 0.1% in controls vs. 1.0 ± 0.3% in the HBO treatment group (p < 0.001); at 48 h: 8.6 ± 0.7% in controls vs. 2.9 ± 0.2% in the HBO treatment group (p < 0.01)] and improved sinusoidal diameter and microvascular density index.

CONCLUSIONS

  Hyperbaric oxygen therapy has persistent positive effects post-OLT that may potentially transfer into clinical practice.