Expansion of hepatic progenitor cell in fatty liver graft after living donor liver transplantation

Rapamycin Upregulates Connective Tissue Growth Factor Expression in Hepatic Progenitor Cells Through TGF-β-Smad2 Dependent Signaling

Rapamycin (sirolimus) is a mTOR kinase inhibitor and is widely used as an immunosuppressive drug to prevent graft rejection in organ transplantation currently. However, some recent investigations have reported that it had profibrotic effect in the progression of organ fibrosis, and its precise role in the liver fibrosis is still poorly understood. Here we showed that rapamycin upregulated connective tissue growth factor (CTGF) expression at the transcriptional level in hepatic progenitor cells (HPCs). Using lentivirus-mediated small hairpin RNA (shRNA) we demonstrated that knockdown of mTOR, Raptor, or Rictor mimicked the effect of rapamycin treatment. Mechanistically, inhibition of mTOR activity with rapamycin resulted in a hyperactive PI3K-Akt pathway, whereas this activation inhibited the expression of CTGF in HPCs. Besides, rapamycin activated the TGF-β-Smad signaling, and TGF-β receptor type I (TGFβRI) serine/threonine kinase inhibitors completely blocked the effects of rapamycin on HPCs. Moreover, Smad2 was involved in the induction of CTGF through rapamycin-activated TGF-β-Smad signaling as knockdown completely blocked CTGF induction, while knockdown of Smad4 expression partially inhibited induction, whereas Smad3 knockdown had no effect. Rapamycin also induced ROS generation and latent TGF-β activation which contributed to TGF-β-Smad signaling. In conclusion, this study demonstrates that rapamycin upregulates CTGF in HPCs and suggests that rapamycin has potential fibrotic effect in liver.

Feasibility of using marginal liver grafts in living donor liver transplantation

Liver transplantation (LT) is one of the most effective treatments for end-stage liver disease caused by related risk factors when liver resection is contraindicated. Additionally, despite the decrease in the prevalence of hepatitis B virus (HBV) over the past two decades, the absolute number of HBsAg-positive people has increased, leading to an increase in HBV-related liver cirrhosis and hepatocellular carcinoma. Consequently, a large demand exists for LT. While the wait time for patients on the donor list is, to some degree, shorter due to the development of living donor liver transplantation (LDLT), there is still a shortage of liver grafts. Furthermore, recipients often suffer from emergent conditions, such as liver dysfunction or even hepatic encephalopathy, which can lead to a limited choice in grafts. To expand the pool of available liver grafts, one option is the use of organs that were previously considered “unusable” by many, which are often labeled “marginal” organs. Many previous studies have reported on the possibilities of using marginal grafts in orthotopic LT; however, there is still a lack of discussion on this topic, especially regarding the feasibility of using marginal grafts in LDLT. Therefore, the present review aimed to summarize the feasibility of using marginal liver grafts for LDLT and discuss the possibility of expanding the application of these grafts.

Expression of hepatic progenitor cell markers in acute cellular rejection of liver allografts-An immunohistochemical study

BACKGROUND

Hepatic progenitor cells (HPC) are induced following liver injury to facilitate regeneration. Acute cellular rejection (ACR) is a common complication after liver transplantation as a result of immune-mediated liver injury. In this study, we characterized HPC phenotype in liver allograft biopsy with ACR. We also explored the correlation between expression HPC immunophenotype and clinicopathological parameters.

METHODS

Forty-four liver allograft biopsies performed between 2008 and 2016 in a single center with histologically proven ACR were examined for immunohistochemical expression of HPC markers CK19 and Sox9. The number of positive-staining cells was assessed and correlated with clinicopathological features by statistical analysis.

RESULTS

HPC phenotype expression as denoted by CK19 and Sox9 staining was detected in the liver tissue with ACR. The numbers of CK19+ and Sox9+ cells were positively correlated. A larger number of CK19+ cells were associated with higher serum aspartate aminotransferase (AST) level at biopsy. By histological rejection score, a larger number of Sox9+ cells were associated with a higher score of bile duct damage.

CONCLUSION

Expression HPC markers were correlated with clinical and histological parameters in ACR. Expression of each individual marker may be more tightly associated with a particular component of the ACR process.

Hemodynamic measurements in a sheep model with a hollow fiber artificial kidney containing modified cellulose

HFAK-RC caused pronounced leukopenia, increase in TXB2 levels in plasma and hemodynamic pressure changes as a reflection of complement activation during EC in sheep. In contrast no increase in TXB2 levels and no changes in hemodynamics are observed with HFAK-MC. The leukopenia and granulocytopenia in the latter is much less pronounced and probably reflects the phenomenon "frustrated phagocytosis".