Chronic kidney disease: a major concern in liver transplantation in the XXI century

Excess Risk of Major Adverse Cardiovascular and Kidney Events after Acute Kidney Injury following Living Donor Liver Transplantation

Acute kidney injury (AKI) is a well-known risk factor for major adverse kidney events (MAKE) and major adverse cardiovascular events (MACE) in nontransplant settings. However, the association between AKI after liver transplantation (LT) and MACE/MAKE is not established. A retrospective cohort analysis including 512 LT recipients was conducted. The incidence of post-LT AKI was 35.0% (n = 179). In total, 13 patients (2.5%) developed de novo coronary artery disease (CAD), 3 patients (0.6%) diagnosed with heart failure (HF), and 11 patients (2.1%) had stroke. The post-LT AKI group showed a higher incidence of CAD and HF than the no post-LT AKI group (4.5% versus 1.5%, p = 0.042; 1.7% versus 0%, p = 0.018; respectively), while there was no significant difference in the stroke events (2.8% versus 1.8%, p = 0.461). Through Cox regression analysis, history of cardiovascular disease (HR 6.51, 95% CI 2.43–17.46), post-LT AKI (HR 3.06, 95% CI 1.39–6.75), and pre-LT diabetes (HR 2.37, 95% CI 1.09–5.17) were identified as independent predictors of MACE; pre-LT chronic kidney disease (HR 9.54, 95% CI 3.49–26.10), pre-LT diabetes (HR 3.51, 95% CI 1.25–9.86), and post-LT AKI (HR 6.76, 95% CI 2.19–20.91) were risk factors for end-stage renal disease. Post-LT AKI is predictive for the development of MACE and MAKE.

Adult liver transplantation: UK clinical guideline - part 2: surgery and post-operation

Survival rates for patients following liver transplantation exceed 90% at 12 months and approach 70% at 10 years. Part 1 of this guideline has dealt with all aspects of liver transplantation up to the point of placement on the waiting list. Part 2 explains the organ allocation process, organ donation and organ type and how this influences the choice of recipient. After organ allocation, the transplant surgery and the critical early post-operative period are, of necessity, confined to the liver transplant unit. However, patients will eventually return to their referring secondary care centre with a requirement for ongoing supervision. Part 2 of this guideline concerns three key areas of post liver transplantation care for the non-transplant specialist: (1) overseeing immunosuppression, including interactions and adherence; (2) the transplanted organ and how to initiate investigation of organ dysfunction; and (3) careful oversight of other organ systems, including optimising renal function, cardiovascular health and the psychosocial impact. The crucial significance of this holistic approach becomes more obvious as time passes from the transplant, when patients should expect the responsibility for managing the increasing number of non-liver consequences to lie with primary and secondary care.

Blood-Bile Barrier: Morphology, Regulation, and Pathophysiology

The term blood-bile barrier (BBlB) refers to the physical structure within a hepatic lobule that compartmentalizes and hence segregates sinusoidal blood from canalicular bile. Thus, this barrier provides physiological protection in the liver, shielding the hepatocytes from bile toxicity and restricting the mixing of blood and bile. BBlB is primarily composed of tight junctions; however, adherens junction, desmosomes, gap junctions, and hepatocyte bile transporters also contribute to the barrier function of the BBlB. Recent findings also suggest that disruption of BBlB is associated with major hepatic diseases characterized by cholestasis and aberrations in BBlB thus may be a hallmark of many chronic liver diseases. Several molecular signaling pathways have now been shown to play a role in regulating the structure and function and eventually contribute to regulation of the BBlB function within the liver. In this review, we will discuss the structure and function of the BBlB, summarize the methods to assess the integrity and function of BBlB, discuss the role of BBlB in liver pathophysiology, and finally, discuss the mechanisms of BBlB regulation. Collectively, this review will demonstrate the significance of the BBlB in both liver homeostasis and hepatic dysfunction.

Dysregulated Bile Transporters and Impaired Tight Junctions During Chronic Liver Injury in Mice

BACKGROUND & AIMS

Liver fibrosis, hepatocellular necrosis, inflammation, and proliferation of liver progenitor cells are features of chronic liver injury. Mouse models have been used to study the end-stage pathophysiology of chronic liver injury. However, little is known about differences in the mechanisms of liver injury among different mouse models because of our inability to visualize the progression of liver injury in vivo in mice. We developed a method to visualize bile transport and blood-bile barrier (BBlB) integrity in live mice.

METHODS

C57BL/6 mice were fed a choline-deficient, ethionine-supplemented (CDE) diet or a diet containing 0.1% 3,5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC) for up to 4 weeks to induce chronic liver injury. We used quantitative liver intravital microscopy (qLIM) for real-time assessment of bile transport and BBlB integrity in the intact livers of the live mice fed the CDE, DDC, or chow (control) diets. Liver tissues were collected from mice and analyzed by histology, immunohistochemistry, real-time polymerase chain reaction, and immunoblots.

RESULTS

Mice with liver injury induced by a CDE or a DDC diet had breaches in the BBlB and impaired bile secretion, observed by qLIM compared with control mice. Impaired bile secretion was associated with reduced expression of several tight-junction proteins (claudins 3, 5, and 7) and bile transporters (NTCP, OATP1, BSEP, ABCG5, and ABCG8). A prolonged (2-week) CDE, but not DDC, diet led to re-expression of tight junction proteins and bile transporters, concomitant with the reestablishment of BBlB integrity and bile secretion.

CONCLUSIONS

We used qLIM to study chronic liver injury, induced by a choline-deficient or DDC diet, in mice. Progression of chronic liver injury was accompanied by loss of bile transporters and tight junction proteins.

New concepts in acute-on-chronic liver failure: Implications for liver transplantation

Acute-on-chronic liver failure (ACLF) is a recently defined syndrome that occurs frequently in patients with cirrhosis and is associated with a poor short-term prognosis. Currently, management of patients with ACLF is mainly supportive. Despite medical progress, this syndrome frequently leads to multiorgan failure, sepsis, and, ultimately, death. The results of attempts to use liver transplantation (LT) to manage this critical condition have been poorly reported but are promising. Currently, selection criteria of ACLF patients for LT, instructions for prioritization on the waiting list, and objective indicators for removal of ACLF patients from the waiting list in cases of clinical deterioration are poorly defined. Before potential changes can be implemented into decisional algorithms, their effects, either on the benefits to individual patients or on global transplant outcomes, should be carefully evaluated using objective longterm endpoints that take into account ethical considerations concerning LT. Liver Transplantation 23 234-243 2017 AASLD.

Metabolic syndrome and non-alcoholic fatty liver disease after liver or kidney transplantation

Transplantation is a definitive treatment option for patients with end-stage liver disease, and for some patients with acute liver failure, hepatocellular carcinoma or end-stage renal disease. Long-term post-transplantation complications have become an important medical issue, and cardiovascular diseases (CVD) are now the leading cause of mortality in liver or kidney transplant recipients. The increased prevalence of metabolic syndrome (MS) likely plays a role in the high incidence of post-transplantation CVD. MS and its hepatic manifestation, non-alcoholic fatty liver disease (NAFLD), are prevalent among the general population and in pre- and post-transplantation settings. MS components are associated with recurrent or de novo NAFLD in transplant recipients, potentially influencing post-transplantation survival. Moreover, recent data reveal an important association between NAFLD and risk of incident of chronic kidney disease (CKD). Therefore, NAFLD identification could represent an additional clinical feature for improving the stratification of liver and kidney transplant recipients with regards to risks of CVD, CKD and renal allograft dysfunction. All MS components are potentially modifiable; therefore, it is crucial that hepatologists, nephrologists and primary care physicians become more engaged in managing post-transplantation metabolic complications. The present review discusses the recent clinical evidence regarding the importance of MS and its components after liver and kidney transplantation, as well as the link between MS and NAFLD after liver and kidney transplantation.