Axon guidance genes control hepatic artery development.

Earlier data on liver development demonstrated that morphogenesis of the bile duct, portal mesenchyme and hepatic artery is interdependent, yet how this interdependency is orchestrated remains unknown. Here, using 2D and 3D imaging, we first describe how portal mesenchymal cells become organised to form hepatic arteries. Next, we examined intercellular signalling active during portal area development and found that axon guidance genes are dynamically expressed in developing bile ducts and portal mesenchyme. Using tissue-specific gene inactivation in mice, we show that the repulsive guidance molecule BMP co-receptor A (RGMA)/neogenin (NEO1) receptor/ligand pair is dispensable for portal area development, but that deficient roundabout 2 (ROBO2)/SLIT2 signalling in the portal mesenchyme causes reduced maturation of the vascular smooth muscle cells that form the tunica media of the hepatic artery. This arterial anomaly does not impact liver function in homeostatic conditions, but is associated with significant tissular damage following partial hepatectomy. In conclusion, our work identifies new players in development of the liver vasculature in health and liver regeneration.

Vascular damage and excessive proliferation compromise liver function after extended hepatectomy in mice.

BACKGROUND AND AIMS: Surgical resection remains the gold standard for liver tumor treatment, yet the emergence of postoperative liver failure, known as the small-for-size syndrome (SFSS), poses a significant challenge. The activation of hypoxia sensors in an SFSS liver remnant initiated early angiogenesis, improving the vascular architecture, safeguarding against liver failure, and reducing mortality. The study aimed to elucidate vascular remodeling mechanisms in SFSS and their impact on hepatocyte function and subsequent liver failure. APPROACH AND RESULTS: Mice underwent extended partial hepatectomy to induce SFSS, with a subset exposed to hypoxia immediately after surgery. Hypoxia bolstered posthepatectomy survival rates. The early proliferation of liver sinusoidal cells, coupled with recruitment of putative endothelial progenitor cells, increased vascular density, improved lobular perfusion, and limited hemorrhagic events in the regenerating liver under hypoxia. Administration of granulocyte colony-stimulating factor in hepatectomized mice mimicked the effects of hypoxia on vascular remodeling and endothelial progenitor cell recruitment but failed to rescue survival. Compared to normoxia, hypoxia favored hepatocyte function over proliferation, promoting functional preservation in the regenerating remnant. Injection of Adeno-associated virus serotype 8-thyroxine-binding globulin-hepatocyte nuclear factor 4 alpha virus for hepatocyte-specific overexpression of hepatocyte nuclear factor 4 alpha, the master regulator of hepatocyte function, enforced functionality in proliferating hepatocytes but did not rescue survival. The combination of hepatocyte nuclear factor 4 alpha overexpression and granulocyte colony-stimulating factor treatment rescued survival after SFSS-setting hepatectomy. CONCLUSIONS: In summary, SFSS arises from an imbalance and desynchronized interplay between functional regeneration and vascular restructuring. To improve survival following SFSS hepatectomy, it is essential to adopt a 2-pronged strategy aimed at preserving the function of proliferating parenchymal cells and simultaneously attenuating vascular damage.

Liver regeneration after portal and hepatic vein embolization improves overall survival compared with portal vein embolization alone: mid-term survival analysis of the multicentre DRAGON 0 cohort.

BACKGROUND: The purpose of this study was to compare 3-year overall survival after simultaneous portal (PVE) and hepatic vein (HVE) embolization versus PVE alone in patients undergoing liver resection for primary and secondary cancers of the liver. METHODS: In this multicentre retrospective study, all DRAGON 0 centres provided 3-year follow-up data for all patients who had PVE/HVE or PVE, and were included in DRAGON 0 between 2016 and 2019. Kaplan-Meier analysis was undertaken to assess 3-year overall and recurrence/progression-free survival. Factors affecting survival were evaluated using univariable and multivariable Cox regression analyses. RESULTS: In total, 199 patients were included from 7 centres, of whom 39 underwent PVE/HVE and 160 PVE alone. Groups differed in median age (P = 0.008). As reported previously, PVE/HVE resulted in a significantly higher resection rate than PVE alone (92 versus 68%; P = 0.007). Three-year overall survival was significantly higher in the PVE/HVE group (median survival not reached after 36 months versus 20 months after PVE; P = 0.004). Univariable and multivariable analyses identified PVE/HVE as an independent predictor of survival (univariable HR 0.46, 95% c.i. 0.27 to 0.76; P = 0.003). CONCLUSION: Overall survival after PVE/HVE is substantially longer than that after PVE alone in patients with primary and secondary liver tumours.

Effective multimodal management of a giant adrenocortical carcinoma.

BACKGROUND: Adrenocortical carcinoma is a rare and aggressive tumour. The only curative treatment is surgery with negative margins. In most series, the average lesion size ranges from 5.5 to 15 cm. METHODS: We report the case of a 27-year-old female with hyperandrogenism and Cushing syndrome due to a right adrenocortical carcinoma of 19.7 cm. RESULTS: The tumour abutting on liver and vena cava and the presence two nodules in liver required extensive surgery including a right posterior sectionectomy and an en bloc resection of the adrenal mass together with the right kidney and the gallbladder. The vena cava was also resected with a reconstruction using a pericardial patch since it was invaded on its border. Pathological examination confirmed an adrenocortical carcinoma, with tumour invasion of vessels, tumour capsule, vena cava and two metastases in the liver (pT4N0M1). All margins were negative. Three months after surgery, two lung nodules, cardio-phrenic and internal mammary adenomegalies were noticed on a PET/CT scan, justifying the initiation of chemotherapy, alongside with mitotane. After a 10-month follow-up, CT scan was stable excepted for a lung nodule growing from 4 to 7 mm. Targeted stereotaxic radiotherapy was then administered. Twenty-two months after surgery, the patient has improved considerably and all signs of hyperandrogenism and Cushing syndrome have resolved. CONCLUSION: This case of adrenocortical carcinoma illustrates one of the largest tumours among those reported. It demonstrates the feasibility and effectiveness of a multimodal approach in its treatment even if it is giant and at high risk.

Selective HIF stabilization alleviates hepatocellular steatosis and ballooning in a rodent model of 70% liver resection.

BACKGROUND: Small-for-size syndrome (SFSS) looms over patients needing liver resection or living-donor transplantation. Hypoxia has been shown to be crucial for the successful outcome of liver resection in the very early postoperative phase. While poorly acceptable as such in real-world clinical practice, hypoxia responses can still be simulated by pharmacologically raising levels of its transducers, the hypoxia-inducible factors (HIFs). We aimed to assess the potential role of a selective inhibitor of HIF degradation in 70% hepatectomy (70%Hx). METHODS: In a pilot study, we tested the required dose of roxadustat to stabilize liver HIF1α. We then performed 70%Hx in 8-week-old male Lewis rats and administered 25 mg/kg of roxadustat (RXD25) at the end of the procedure. Regeneration was assessed: ki67 and 5-ethynyl-2'-deoxyuridine (EdU) immunofluorescent labeling, and histological parameters. We also assessed liver function via a blood panel and functional gadoxetate-enhanced magnetic resonance imaging (MRI), up to 47 h after the procedure. Metabolic results were analyzed by means of RNA sequencing (RNAseq). RESULTS: Roxadustat effectively increased early HIF1α transactivity. Liver function did not appear to be improved nor liver regeneration to be accelerated by the experimental compound. However, treated livers showed a mitigation in hepatocellular steatosis and ballooning, known markers of cellular stress after liver resection. RNAseq confirmed that roxadustat unexpectedly increases lipid breakdown and cellular respiration. CONCLUSIONS: Selective HIF stabilization did not result in an enhanced liver function after standard liver resection, but it induced interesting metabolic changes that are worth studying for their possible role in extended liver resections and fatty liver diseases.

Critical Role of LSEC in Post-Hepatectomy Liver Regeneration and Failure.

Liver sinusoids are lined by liver sinusoidal endothelial cells (LSEC), which represent approximately 15 to 20% of the liver cells, but only 3% of the total liver volume. LSEC have unique functions, such as fluid filtration, blood vessel tone modulation, blood clotting, inflammatory cell recruitment, and metabolite and hormone trafficking. Different subtypes of liver endothelial cells are also known to control liver zonation and hepatocyte function. Here, we have reviewed the origin of LSEC, the different subtypes identified in the liver, as well as their renewal during homeostasis. The liver has the exceptional ability to regenerate from small remnants. The past decades have seen increasing awareness in the role of non-parenchymal cells in liver regeneration despite not being the most represented population. While a lot of knowledge has emerged, clarification is needed regarding the role of LSEC in sensing shear stress and on their participation in the inductive phase of regeneration by priming the hepatocytes and delivering mitogenic factors. It is also unclear if bone marrow-derived LSEC participate in the proliferative phase of liver regeneration. Similarly, data are scarce as to LSEC having a role in the termination phase of the regeneration process. Here, we review what is known about the interaction between LSEC and other liver cells during the different phases of liver regeneration. We next explain extended hepatectomy and small liver transplantation, which lead to "small for size syndrome" (SFSS), a lethal liver failure. SFSS is linked to endothelial denudation, necrosis, and lobular disturbance. Using the knowledge learned from partial hepatectomy studies on LSEC, we expose several techniques that are, or could be, used to avoid the "small for size syndrome" after extended hepatectomy or small liver transplantation.

Associating liver partition and portal vein ligation for staged hepatectomy: establishment of an animal model with insufficient liver remnant.

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) allows extended hepatectomy in patients with an extremely small future liver remnant (FLR). Current rodent models of ALPPS do not include resection resulting in insufficient-for-survival FLR, or they do incorporate liver mass reduction prior to ALPPS. Differences in FLR volume and surgical procedures could bias our understanding of physiological and hemodynamic mechanisms. We aimed to establish a rat ALPPS model with minimal FLR without prior parenchymal resection. In rodents, the left median lobe (LML) represents 10% of total liver. Partial hepatectomy (PHx) sparing LML and pericaval parenchyma represents our reference 87% resection. The first step in the procedure is either portal vein ligation (PVL) corresponding to ligation of all but the LML portal branches, or PVL with transection between the left and right median lobe segments (PVLT), and is defined as ALPPS stage-1. Second, ligated lobes were removed: PVL-PHx represents a conventional 2-stage hepatectomy, while PVLT followed by PHx is a strict reproduction of human ALPPS. In Group A, liver hypertrophy was analyzed after PVL (n = 38), PVLT (n = 47), T (n = 10), and sham (n = 10); In group B, mortality and FLR hypertrophy was assessed after PHx (n = 42), Sham-PHx (n = 6), PVL-PHx (n = 37), and PVLT-PHx (n = 45). In group A, PVLT induced rapid FLR hypertrophy compared to PVL (p < 0,05). Hepatocyte proliferation was higher in PVLT remnants (p < 0,05). In group B, PHx had a 5-day mortality rate of 84%. Sham operation prior to PHx did not improve survival (p = 0.23). In both groups, major fatalities occurred within 48 h after resection. PVL or PVLT prior to PHx reduced mortality to 33.3% (p = 0,007) or 25% (p = 0.0002) respectively, with no difference between the 2 two-stage procedures (p = 0.6). 7-day FLR hypertrophy was higher after the PVLT-PHx compared to PVL-PHx and PHx (p = 0.024). Our model reproduces human ALPPS with FLR that is insufficient for survival without liver resection prior to the stage-1 procedure. It offers an appropriate model for analyzing the mechanisms driving survival rescue and increased hypertrophy.

Hypoxia protects the liver from Small For Size Syndrome: A lesson learned from the associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) procedure in rats.

Portal hyperperfusion and "dearterialization" of the liver remnant are the main pathogenic mechanisms for Small For Size syndrome (SFSS). Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) induces rapid remnant hypertrophy. We hypothesized a similar increase in portal pressure/flow into the future liver remnant in ALPPS and SFSS-setting hepatectomies. In a rodent model, ALPPS was compared to SFSS-setting hepatectomy. We assessed mortality, remnant hypertrophy, hepatocyte proliferation, portal and hepatic artery flow, hypoxia-induced response, and liver sinusoidal morphology. SFSS-hepatectomy rats were subjected to local (hepatic artery ligation) or systemic (Dimethyloxalylglycine) hypoxia. ALLPS prevented mortality in SFSS-setting hepatectomies. Portal hyperperfusion per liver mass was similar in ALLPS and SFSS. Compared to SFSS, efficient arterial perfusion of the remnant was significantly lower in ALPPS causing pronounced hypoxia confirmed by pimonidazole immunostaining, activation of hypoxia sensors and upregulation of neo-angiogenic genes. Liver sinusoids, larger in ALPPS, collapsed in SFSS. Induction of hypoxia in SFSS reduced mortality. Hypoxia had no impact on hepatocyte proliferation but contributed to the integrity of sinusoidal morphology. ALPPS hemodynamically differ from SFSS by a much lower arterial flow in ALPPS's FLR. We show that the ensuing hypoxic response is essential for the function of the regenerating liver by preserving sinusoidal morphology.

The practice of laparoscopic liver surgery in Belgium: a national survey.

BACKGROUND: Laparoscopic liver surgery (LLS) gained popularity bringing several advantages including decreased morbidity and reduction of length of hospital stay compared to open. METHODS: To understand practice and evolution of LLS in Belgium, a 20-questions survey was sent to all members of the Royal Belgian Society for Surgery, the Belgian Section of Hepato-Pancreatic and Biliary Surgery and the Belgian Group for Endoscopic Surgery. RESULTS: Thirty-seven surgical units representing 61 surgeons performing LLS in Belgium responded: 50% from regional hospitals, 28% from university and 22% from peripheral hospitals. Replies from high volume centers (>50 liver-surgery/year) were 19%. More than 25% of liver procedures were performed laparoscopically in 35% of centers. LLS is adopted since more than 15-years in 14.5% of centers with an increasing rate reported in 59%. Low relevance of LLS in the hospital organization (26.5%) and lack of time in surgical schedules (12%) or of specific training (9%) are the main barriers for further diffusion. More than 80% of the responders agreed to participate to a national prospective registry. CONCLUSION: LLS is mainly performed in experienced HPB units with an increasing interest in peripheral centers. A prospective national registry will be useful by providing real data in terms of indications, morbidity and overall evolution.

Incidence and Prognosis of Biliary Tract and Gallbladder Cancers in a Belgian Academic Hospital.

BACKGROUND: Biliary tract and gallbladder cancers are rare tumors with a poor prognosis (except the ampulla type). The evolution of hepatobiliary cancer incidence varies widely around the world. According to the Belgian Cancer Registry, the number of hepatobiliary cancers has increased every year since 2004. MATERIALS AND METHODS: This retrospective study included patients diagnosed with cholangiocarcinoma, ampulla cancer, or gallbladder cancer at the university hospital, CHU UCL, Godinne site, in Namur, Belgium, between 1997 and 2017. The evolution of cancer incidence was evaluated with the Mann-Kendall method, by analyzing 7 consecutive 3-year periods. We calculated survival with the Kaplan-Meier method, and we determined prognostic factors with the log-rank test and Cox models. RESULTS: Between 1997 and 2017, we included 128 patients that were newly diagnosed in our center. According to the Mann-Kendall test, the evolution of the incidence of these cancers in our hospital increased significantly over the study period (Sen's slope = 7; p = 0.003). The 1-year overall survival was 53.0 ± 4.7%. Poor prognostic factors included age, cancer stage, local cancer extension, and metastatic disease. The independent prognostic factors of survival were age (p = 0.002), ampulla cancer (p < 0.001), and metastatic disease (p < 0.001). CONCLUSIONS: We found that the incidence of biliary tract and gallbladder cancers increased over a period of 20 years in our center. Further investigations are needed to determine the reasons for this increase. Although new therapies are emerging, the prognosis remains poor for these cancers. Determining risk factors might promote the development of preventive approaches.

Impact of biological agents on the prevalence of chemotherapy associated liver injury (CALI): Multicentric study of patients operated for colorectal liver metastases.

BACKGROUND: The prevalence of chemotherapy associated liver injuries (CALI), especially SOS (sinusoidal obstruction syndrome) and NRH (nodular regenerative hyperplasia) might be reduced since the introduction of routine use of biological agents with chemotherapy in colorectal liver metastases (CRLM). METHODS: One hundred patients with CRLM having undergone at least one liver segment resection were prospectively included, and chemotherapy data recorded. Specimens were reviewed by a single pathologist and CALI were described. Prevalence of CALI was compared to our previous experience published in 2013. NRH diagnosis was performed on reticulin special stain, by contrast to our previous study. Postoperative outcome was analysed. RESULTS: Bevacizumab was more frequently administrated in patients of the present study: 53/100 (53%) compared to 20/151 (13%), p < 0.0001. Overall, in the present series, SOS was only observed in 28/100 (28%) patients compared to 116/151 (77%) in 2013 (p < 0.001). When looking specifically to patients receiving Bevacizumab with Folfox, we observed a reduced SOS prevalence compared to Folfox alone (p = 0.008). A higher prevalence of NRH was found in the present study, related to increased detection accuracy, but in patients receiving Bevacizumab in association with Folfox, this prevalence was also reduced compared to Folfox alone (p = 0.03). Both SOS and NRH were associated with severe complications (p = 0.008 and p = 0.005, respectively) and postoperative liver insufficiency (p < 0.001 and p < 0.01, respectively). CONCLUSIONS: The routine use of Bevacizumab in association with Folfox significantly reduced CALI prevalence, in turn linked to severe postoperative complications.

Laparoscopic ultrasonography as an alternative to intraoperative cholangiography during laparoscopic cholecystectomy.

AIM: To assess the role of laparoscopic ultrasound (LUS) as a substitute for intraoperative cholangiography (IOC) during cholecystectomy. METHODS: We present a MEDLINE and PubMed literature search, having used the key-words "laparoscopic intraoperative ultrasound" and "laparoscopic cholecystectomy". All relevant English language publications from 2000 to 2016 were identified, with data extracted for the role of LUS in the anatomical delineation of the biliary tract, detection of common bile duct stones (CBDS), prevention or early detection of biliary duct injury (BDI), and incidental findings during laparoscopic cholecystectomy. Data for the role of LUS vs IOC in complex situations (i.e., inflammatory disease/fibrosis) were specifically analyzed. RESULTS: We report data from eighteen reports, 13 prospective non-randomized trials, 5 retrospective trials, and two meta-analyses assessing diagnostic accuracy, with one analysis also assessing costs, duration of the examination, and anatomical mapping. Overall, LUS was shown to provide highly sensitive mapping of the extra-pancreatic biliary anatomy in 92%-100% of patients, with more difficulty encountered in delineation of the intra-pancreatic segment of the biliary tract (73.8%-98%). Identification of vascular and biliary variations has been documented in two studies. Although inflammatory disease hampered accuracy, LUS was still advantageous vs IOC in patients with obscured anatomy. LUS can be performed before any dissection and repeated at will to guide the surgeon especially when hilar mapping is difficult due to fibrosis and inflammation. In two studies LUS prevented conversion in 91% of patients with difficult scenarios. Considering CBDS detection, LUS sensitivity and specificity were 76%-100% and 96.2%-100%, respectively. LUS allowed the diagnosis/treatment of incidental findings of adjacent organs. No valuable data for BDI prevention or detection could be retrieved, even if no BDI was documented in the reports analyzed. Literature analysis proved LUS as a safe, quick, non-irradiating, cost-effective technique, which is comparatively well known although largely under-utilized, probably due to the perception of a difficult learning curve. CONCLUSION: We highlight the advantages and limitations of laparoscopic ultrasound during cholecystectomy, and underline its value in difficult scenarios when the anatomy is obscured.