Maternal obesity increases the risk of hepatocellular carcinoma through the transmission of an altered gut microbiome.

Background & Aims: Emerging evidence suggests that maternal obesity negatively impacts the health of offspring. Additionally, obesity is a risk factor for hepatocellular carcinoma (HCC). Our study aims to investigate the impact of maternal obesity on the risk for HCC development in offspring and elucidate the underlying transmission mechanisms. Methods: Female mice were fed either a high-fat diet (HFD) or a normal diet (ND). All offspring received a ND after weaning. We studied liver histology and tumor load in a N-diethylnitrosamine (DEN)-induced HCC mouse model. Results: Maternal obesity induced a distinguishable shift in gut microbial composition. At 40 weeks, female offspring of HFD-fed mothers (HFD offspring) were more likely to develop steatosis (9.43% vs. 3.09%, p = 0.0023) and fibrosis (3.75% vs. 2.70%, p = 0.039), as well as exhibiting an increased number of inflammatory infiltrates (4.8 vs. 1.0, p = 0.018) and higher expression of genes involved in fibrosis and inflammation, compared to offspring of ND-fed mothers (ND offspring). A higher proportion of HFD offspring developed liver tumors after DEN induction (79.8% vs. 37.5%, p = 0.0084) with a higher mean tumor volume (234 vs. 3 µm3, p = 0.0041). HFD offspring had a significantly less diverse microbiota than ND offspring (Shannon index 2.56 vs. 2.92, p = 0.0089), which was rescued through co-housing. In the principal component analysis, the microbiota profile of co-housed animals clustered together, regardless of maternal diet. Co-housing of HFD offspring with ND offspring normalized their tumor load. Conclusions: Maternal obesity increases female offspring's susceptibility to HCC. The transmission of an altered gut microbiome plays an important role in this predisposition. Impact and implications: The worldwide incidence of obesity is constantly rising, with more and more children born to obese mothers. In this study, we investigate the impact of maternal diet on gut microbiome composition and its role in liver cancer development in offspring. We found that mice born to mothers with a high-fat diet inherited a less diverse gut microbiome, presented chronic liver injury and an increased risk of developing liver cancer. Co-housing offspring from normal diet- and high-fat diet-fed mothers restored the gut microbiome and, remarkably, normalized the risk of developing liver cancer. The implementation of microbial screening and restoration of microbial diversity holds promise in helping to identify and treat individuals at risk to prevent harm for future generations.

Portosystemic shunting prevents hepatocellular carcinoma in non-alcoholic fatty liver disease mouse models.

BACKGROUND AND AIMS: Non-alcoholic fatty liver disease (NAFLD) is one of the leading cause of hepatocellular carcinoma (HCC). This association is supported by the translocation of bacteria products into the portal system, which acts on the liver through the gut-liver axis. We hypothesize that portosystemic shunting can disrupt this relationship, and prevent NAFLD-associated HCC. METHODS: HCC carcinogenesis was tested in C57BL/6 mice fed a high-fat high-sucrose diet (HFD) and injected with diethylnitrosamine (DEN) at two weeks of age, and in double transgenic LAP-tTA and TRE-MYC (LAP-Myc) mice fed a methionine-choline-deficient diet. Portosystemic shunts were established by transposing the spleen to the sub-cutaneous tissue at eight weeks of age. RESULTS: Spleen transposition led to a consistent deviation of part of the portal flow and a significant decrease in portal pressure. It was associated with a decrease in the number of HCC in both models. This effect was supported by the presence of less severe liver steatosis after 40 weeks, and lower expression levels of liver fatty acid synthase. Also, shunted mice exhibited lower liver oxygen levels, a key factor in preventing HCC as confirmed by the development of less HCCs in mice with hepatic artery ligation. CONCLUSIONS: The present data show that portosystemic shunting prevents NAFLD-associated HCC, utilizing two independent mouse models. This effect is supported by the development of less steatosis, and a restored liver oxygen level. Portal pressure modulation and shunting deserve further exploration as potential prevention/treatment options for NAFLD and HCC.

Anti-CD122 antibody restores specific CD8+ T cell response in nonalcoholic steatohepatitis and prevents hepatocellular carcinoma growth.

Nonalcoholic steatohepatitis (NASH) can lead to hepatocellular carcinoma (HCC). Although immunotherapy is used as first-line treatment for advanced HCC, the impact of NASH on anticancer immunity is only partially characterized. We assessed the tumor-specific T cell immune response in the context of NASH. In a mouse model of NASH, we observed an expansion of the CD44+CXCR6+PD-1+CD8+ T cells in the liver. After intra-hepatic injection of RIL-175-LV-OVA-GFP HCC cells, NASH mice had a higher percentage of peripheral OVA-specific CD8+ T cells than control mice, but these cells did not prevent HCC growth. In the tumor, the expression of PD-1 on OVA-specific CD44+CXCR6+CD8+ cells was higher in NASH mice suggesting lowered immune activity. Treating mice with an anti-CD122 antibody, which reduced the number of CXCR6+PD-1+ cells, we restored OVA-specific CD8 activity, and reduced HCC growth compared to untreated NASH mice. Human dataset confirmed that NASH-affected livers, NASH tissues adjacent to HCC and HCC in patients with NASH exhibited gene expression patterns supporting mouse observations. Our findings demonstrate the immune system fails to prevent HCC growth in NASH, primarily linked to a higher representation of CD44+CXCR6+PD-1+CD8+ T cells. Treatment with an anti-CD122 antibody reduces the number of these cells and prevents HCC growth.

The impact of short-term machine perfusion on the risk of cancer recurrence after rat liver transplantation with donors after circulatory death.

Hypothermic and normothermic ex vivo liver perfusions promote organ recovery after donation after circulatory death (DCD). We tested whether these perfusions can reduce the risk of hepatocellular carcinoma (HCC) recurrence in a 1h-DCD syngeneic transplantation model, using Fischer F344 rats. DCD grafts were machine perfused for 2h with hypothermic perfusion (HOPE) or normothermic perfusion (NORMO), and transplanted. After reperfusion, we injected HCC cells into the vena porta. On day 28 after transplantation, we assessed tumour volumes by MRI. Control rats included transplantations with Fresh and non-perfused DCD livers. We observed apoptotic-necrotic hepatocyte foci in all DCD grafts, which were more visible than in the Fresh liver grafts. Normothermic perfusion allowed a faster post-transplant recovery, with lower day 1 levels of transaminases compared with the other DCD. Overall, survival was similar in all four groups and all animals developed HCCs. Total tumor volume was lower in the Fresh liver recipients compared to the DCD and DCD+HOPE recipients. Volumes in DCD+NORMO recipients were not significantly different from those in the Fresh group. This experiment confirms that ischemia/reperfusion injury promotes HCC cell engraftment/growth after DCD liver transplantation. Using the present extreme 1h ischemia model, both hypothermic and normothermic perfusions were not effective in reducing this risk.

Effects of remote ischaemic preconditioning on intraportal islet transplantation in a rat model.

Remote ischaemic preconditioning (RIPC), which is the intermittent interruption of blood flow to a site distant from the target organ, is known to improve solid organ resistance to ischaemia-reperfusion injury. This procedure could be of interest in islet transplantation to mitigate hypoxia-related loss of islet mass after isolation and transplantation. Islets isolated from control or RIPC donors were analyzed for yield, metabolic activity, gene expression and high mobility group box-1 (HMGB1) content. Syngeneic marginal mass transplantation was performed in four streptozotocin-induced diabetic groups: control, RIPC in donor only, RIPC in recipient only, and RIPC in donor and recipient. Islets isolated from RIPC donors had an increased yield of 20% after 24 h of culture compared to control donors (P = 0.007), linked to less cell death (P = 0.08), decreased expression of hypoxia-related genes (Hif1a P = 0.04; IRP94 P = 0.008), and increased intra-cellular (P = 0.04) and nuclear HMGB1. The use of RIPC in recipients only did not allow for reversal of diabetes, with increased serum HMGB1 at day 1; the three other groups demonstrated significantly better outcomes. Performing RIPC in the donors increases islet yield and resistance to hypoxia. Validation is needed, but this strategy could help to decrease the number of donors per islet recipient.

Efficient nonarterialized mouse liver transplantation using 3-dimensional-printed instruments.

Because of the wide availability of genetically modified animals, mouse orthotopic liver transplantation is often preferred over rat liver transplantation. We present a simplified mouse liver transplantation technique and compare transplantation outcomes with versus without hepatic artery anastomosis. Instruments for liver implantation were designed and printed with a 3-dimensional (3D) printer. The suprahepatic vena cava anastomosis was performed with a 10-0 running suture. The vena porta and infrahepatic vena cava were joined on extraluminal cuffs, using the 3D-printed device for spatial alignment and stabilization. The hepatic artery was reconstructed in half of the recipients using intraluminal stents. Liver function tests (3, 7, and 28 days) and histology (7 and 28 days) were assessed after transplantation. We performed 22 consecutive syngeneic C57BL/6 mouse orthotopic liver transplantations. The median portal clamping time was 12.5 ± 1.5 minutes. The survival rate at 4 weeks was 100% for both arterialized and nonarterialized recipients (n = 7, 4 recipients of each group being killed for early histology at day 7). Liver function tests at 3, 7, and 28 days were similar between arterialized versus nonarterialized groups. Liver parenchyma demonstrated only irrelevant abnormalities in both groups. The proposed device allows for a shorter clamping time compared with the published literature. Using this technique, the artery does not need to be anastomosed, with no impact on graft and recipient outcomes. The device is available for 3D printing. Liver Transplantation 22 1688-1696 2016 AASLD.