Delayed rearterialization unlikely leads to nonanastomotic stricture but causes temporary injury on bile duct after liver transplantation

Prognostic Factors for Non-anastomotic Biliary Strictures Following Adult Liver Transplantation: A Systematic Review and Meta-Analysis

INTRODUCTION

The development of non-anastomotic biliary strictures (NAS) following orthotopic adult liver transplantation (OLT) is associated with significant morbidity. We performed a systematic review and meta-analysis to identify all prognostic factors for the development of NAS.

METHODS

A systematic review was conducted following preferred reporting items for systematic reviews and meta-analyses (PRISMA) and the meta-analysis of observational studies in epidemiology (MOOSE) guidelines. We used the Newcastle-Ottawa scale to assess the quality of the included studies. Using the random-effects model, we calculated the weighted pooled odds ratios (OR), mean differences (MD), hazard ratios (HR), and 95% confidence intervals (CI) of the risk factors.

RESULTS

Based on 19 international studies that included a total of 8269 adult LT patients, we calculated an 8% overall incidence of NAS. In this study, 7 potential prognostic factors were associated with a statistically significant hazard ratio for NAS in pooled analyses including (1) DCD donors compared to DBD donors (2) PSC as an indication for a liver transplant (3) Roux-en-Y bile duct reconstruction compared to duct-to-duct reconstruction (4) hepatic artery thrombosis (5) longer cold ischemia time (6) longer warm ischemia time (7) and total operative times.

CONCLUSION

In this systematic review and meta-analysis, we identified 7 prognostic factors for the development of NAS following OLT. These findings might lay the groundwork for development of diagnostic algorithms to better risk stratify patients at risk for development of NAS.

Protective mechanisms and current clinical evidence of hypothermic oxygenated machine perfusion (HOPE) in preventing post-transplant cholangiopathy

The development of cholangiopathies after liver transplantation impacts on the quality and duration of graft and patient survival, contributing to higher costs as numerous interventions are required to treat strictures and infections at the biliary tree. Prolonged donor warm ischaemia time in combination with additional cold storage are key risk factors for the development of biliary strictures. Based on this, the clinical implementation of dynamic preservation strategies is a current hot topic in the field of donation after circulatory death (DCD) liver transplantation. Despite various retrospective studies reporting promising results, also regarding biliary complications, there are only a few randomised-controlled trials on machine perfusion. Recently, the group from Groningen has published the first randomised-controlled trial on hypothermic oxygenated perfusion (HOPE), demonstrating a significant reduction of symptomatic ischaemic cholangiopathies with the use of a short period of HOPE before DCD liver implantation. The most likely mechanism for this important effect, also shown in several experimental studies, is based on mitochondrial reprogramming under hypothermic aerobic conditions, e.g. exposure to oxygen in the cold, with a controlled and slow metabolism of ischaemically accumulated succinate and simultaneous ATP replenishment. This unique feature prevents mitochondrial oxidative injury and further downstream tissue inflammation. HOPE treatment therefore supports livers by protecting them from ischaemia-reperfusion injury (IRI), and thereby also prevents the development of post-transplant biliary injury. With reduced IRI-associated inflammation, recipients are also protected from activation of the innate immune system, with less acute rejections seen after HOPE.

Effect of HSP27 and Cofilin in the injury of hypoxia/reoxygenation on hepatocyte membrane F-actin microfilaments

Hypoxia-reoxygenation (H/R) injury hepatocyte models were established to simulate the ischemia/reperfusion injury of transplanted organ. Through the study of the molecular mechanism of H/R on the F-actin damage of the liver cytomembrane, the mechanism of F-actin damage induced by ischemia and reperfusion was studied from the level of cell and molecule.The hypoxic environment of cells in vitro was simulated by chemical hypoxia agent CoCl2. Liver cells were detected by MTT, H/R group was subdivided into 3 subgroups: H/R 2, 4, and 6 h. Changes of cell shape and the growth state, apoptosis, ultrastructural changes, and the changes in F-actin microfilament content were observed. Heat shock protein 27 (HSP27), Cofilin, and F-actin gene and protein levels were determined by real-time polymerase chain reaction and western blot assay, respectively.Cells showed circular adherence growth under normal circumstances, while the spindle cells and shedding cells were significantly increased in H/R groups. Apoptosis cells in H/R group were increased significantly with the extension of hypoxia time. The number of endoplasmic reticulum was decreased significantly in the H/R group, the mitochondrion hydropic was degenerated and the glycogen was disappeared. The F-actin fibers in the H/R group were disordered, the morphology of the fibers was obviously decreased, and the fluorescence staining decreased obviously (P < .05). The transcription and expression levels of HSP27, Cofilin, and F-actin were significantly lower than those in the control group (P < .05).These results demonstrate that H/R can affect the correct assembly of F-actin microfilaments and weakens the normal cycle of F-actin microfilaments through inhibiting the protein expression and gene transcription of HSP27 and Cofilin in hepatocytes, thereby changing the skeleton of F-actin microfilaments.