Metallic Stents for Hepatic Venous Outflow Obstruction After Living-Donor Liver Transplantation and their Therapeutic Effects.

BACKGROUND: Living-donor liver transplantation (LDLT) is established as a standard therapy for end-stage liver disease; however, vessel reconstruction is more demanding due to the short length and small size of the available structures compared with deceased-donor whole liver transplantation. Interventional radiology (IR) has become the first-line treatment for vascular complications after LDLT. Hepatic venous outflow obstruction (HVOO) is a life-threatening complication after LDLT. The aim of this study of 592 adult-to-adult LDLT cases was to investigate the safety and efficacy of stent implantation for HVOO after LDLT. METHODS: Records of patients who developed HVOO requiring any treatment were collected with special reference to the metallic stent implantation. There were 232 left-side grafts and 360 right-side grafts. Sixteen cases developed HVOO after LDLT with an incidence rate of 2.7%, 5 with a left liver graft (2%), and 11 with a right-side graft (3%). The IR was attempted for 14 cases; among those, 8 cases were treated by stent implantation. RESULTS: The technical success rate of the initial stent implantation was 100%. The pressure gradient at the stenotic site significantly improved from 12.2 (range, 10.9-20.4 cm H2O) to 3.9 cm H2O (range, 1.4-8.2 cm H2O; P = .03). The volume of the congested graft liver decreased significantly from 1448 (range, 788-2170 mL) to 1265 mL (range, 748-1665 mL; P = .01), and the serum albumin level improved significantly from 3.3 (range, 1.7-3.7 g/dL) to 3.7 g/dL (range, 2.9-4.1 g/dL; P = .02). No procedure-related complication was noted, and the long-term stent patency was 100%. CONCLUSION: Metallic stent implantation for stenotic venous anastomosis after LDLT is a safe and effective treatment.

Two-step artificial intelligence algorithm for liver segmentation automates anatomic virtual hepatectomy.

BACKGROUND: Anatomic virtual hepatectomy with precise liver segmentation for hemilivers, sectors, or Couinaud's segments using conventional three-dimensional simulation is not automated and artificial intelligence (AI)-based algorithms have not yet been applied. METHODS: Computed tomography data of 174 living-donor candidates for liver transplantation (training data) were used for developing a new two-step AI algorithm to automate liver segmentation that was validated in another 51 donors (validation data). The Pure-AI (no human intervention) and ground truth (GT, full human intervention) data groups were compared. RESULTS: In the Pure-AI group, the median Dice coefficients of the right and left hemilivers were highly similar, 0.95 and 0.92, respectively; sectors, posterior to lateral: 0.86-0.92, and Couinaud's segments 1-8: 0.71-0.89. Labeling of the first-order branch as hemiliver, right or left portal vein perfectly matched; 92.8% of the second-order (sectors); 91.6% of third-order (segments) matched between the Pure-AI and GT data. CONCLUSIONS: The two-step AI algorithm for liver segmentation automates anatomic virtual hepatectomy. The AI-based algorithm correctly divided all hemilivers, and more than 90% of the sectors and segments.

Conditional recurrence analysis of intrahepatic cholangiocarcinoma: Changes in recurrence rate and survival after recurrence resection by disease-free interval.

AIM: The prognosis of patients with resected intrahepatic cholangiocarcinoma (ICC) is still unsatisfactory, with a high recurrence rate. We aimed to evaluate risks of recurrence changing over time and the survival benefit of resection for recurrent ICC. METHODS: This study included patients who underwent hepatectomy for ICC during 1995-2020. Risk factors for recurrence-free survival (RFS) in patients undergoing initial resection and overall survival (OS) in patients who developed recurrence after initial resection were analyzed. Conditional cumulative incidence of recurrence was assessed. RESULTS: A total of 169 patients were included in the study and 114 patients (67.5%) developed recurrence. Cumulative analyses showed that the 5-year recurrence rate was 69.3% at the time of initial resection but decreased to 24.8% in patients free from recurrence at 2 years after initial resection and 2.6% in patients free from recurrence at 4 years. Re-resection was carried out in 26 (22.8%) of 114 patients who developed recurrence. Multivariable Cox proportional hazards model analysis indicated re-resection (hazard ratio [HR] 0.19; 95% confidence interval [CI] 0.11-0.40, p < 0.001), microvascular invasion (MVI) (HR 2.39; 95% CI 1.05-5.40, p = 0.037), and disease-free interval (months) (HR 0.97; 95% CI 0.95-1.00, p = 0.067) were significantly associated with longer OS after recurrence. CONCLUSIONS: Although the rate of recurrence remains high, conditional cumulative recurrence rate analysis showed that the rate of recurrence decreased by disease-free interval. Resection of recurrent ICC was associated with improved OS, particularly among patients with longer disease-free interval and absence of MVI after initial hepatectomy.

Improving the sensitivity of liver tumor classification in ultrasound images via a power-law shot noise model.

Power laws have been observed in various fields and help us understand natural phenomena. Power laws have also been observed in ultrasound images. This study used the power spectrum of the signal identified from the reflected ultrasound signal observed in ultrasonography based on the power-law shot noise (PLSN) model. The power spectrum follows a power law, which has a scaling factor that depends on the characteristics of the tissue in the region where the ultrasound wave propagates. To distinguish between a tumor and blood vessels in the liver, we propose a classification model that includes a scaling factor based on ResNet, a deep learning model for image classification. In a task to classify 6 types of tissue - a tumor, the inferior vena cava, the descending aorta, the Gleason sheath, the hepatic vein, and small blood vessels - tumor sensitivity increased 3.8% and the F-score for a tumor improved 2% while precision was maintained. The scaling factor obtained using the PLSN model was validated for classification of liver tumors.

Assessment of liver function-related mRNA expression and fluorescence imaging in outflow-obstructed regions in rats.

PURPOSE: The liver function in outflow-obstructed regions is reportedly impaired; however, the functional decrease has not been quantitatively assessed. We therefore evaluated the uptake of indocyanine green (ICG) into hepatocytes and the mRNA expression associated with the liver function in outflow-obstructed regions using rat models. METHODS: A total of 20 rats with the ligation of the right median hepatic vein to induce outflow obstruction were studied. Five rats each were grouped by the time of re-laparotomy, and the fluorescence intensity (FI) values of ICG. The mRNA expression, including that of Albumin, Cytochrome P450 (Cyp) 1a2, Cyp3a1, Cyp7a1, and Gamma-glutamylcysteine synthetase, in outflow-obstructed (mRNAOut-Ob) and non-outflow-obstructed (mRNANon) regions was assessed. RESULTS: Microscopic fluorescence imaging showed that the FI values were significantly lower in outflow-obstructed regions than in non-outflow-obstructed regions at 12 h, 24 h, and 3 days after ligation of the hepatic vein. The mRNAOut-Ob/mRNANon ratios decreased to approximately 30% at 12 h after the outflow obstruction and increased to approximately 70-80% at 7 days. CONCLUSIONS: The liver function in outflow-obstructed regions was impaired in terms of the uptake of ICG and the mRNA expression. Our findings may help estimate the postoperative functional remnant liver volume by considering the decrease in the liver function in outflow-obstructed regions.

Venous invasion and lymphatic invasion are correlated with the postoperative prognosis of pancreatic neuroendocrine neoplasm.

BACKGROUND: To determine treatment strategies corresponding to a wide range of pancreatic neuroendocrine neoplasms staging, easier-to-use and detailed prognostic classification is required. METHODS: Patients with pancreatic neuroendocrine neoplasms who underwent curative-intent surgery at the University of Tokyo Hospital between 2000 and 2018 were retrospectively reviewed. The presence or absence of venous and lymphatic invasion was assessed. Multivariable analysis was performed to identify the risk factors of shorter overall survival and recurrence-free survival. Patients were classified into the following 3 groups: a lymphovascular invasion 0 group, whereby both venous and lymphatic invasion were negative; an lymphovascular invasion 1 group, where either of the 2 was positive; and an lymphovascular invasion 2 group, where both were positive. The survival curves and recurrence patterns of the 3 groups were compared. RESULTS: Eighty-nine patients were analyzed. Multivariable analysis revealed that lymphatic invasion and Ki-67 index (≥ 3.0%) were independent prognostic factors of recurrence-free survival (hazard ratio: 5.2 and 3.6). Fifty-three patients were classified as lymphovascular invasion 0, 26 as lymphovascular invasion 1, and 10 as lymphovascular invasion 2. The recurrence-free survival curves of the 3 groups were significantly stratified (10-year recurrence-free survival: 89.1% in lymphovascular invasion 0, 57.1% in lymphovascular invasion 1, and 18.3% in lymphovascular invasion 2). Five-year cumulative liver and lymph node metastasis of lymphovascular invasion 0, lymphovascular invasion 1, and lymphovascular invasion 2 were well stratified at 0% and 3.8%, 15.8% and 23.1%, and 33.3% and 70.0%, respectively. CONCLUSION: Postoperative prognosis of resected pancreatic neuroendocrine neoplasms could be finely classified by venous invasion and lymphatic invasion. Management after curative-intent surgery for pancreatic neuroendocrine neoplasms may be changed by this new classification.

Automated liver tumor detection in abdominal ultrasonography with a modified faster region-based convolutional neural networks (Faster R-CNN) architecture.

Background: Although diagnostic ultrasound can non-invasively capture the image of abdominal viscera, diagnosis of the continuous ultrasound liver images to detect a liver tumor effectively and to determine whether the detected is benign or malignant is nontrivial. In order to minimize the gaps in diagnostic accuracy depending on doctor's proficiency, we built an automated system to support the ultrasonography of liver tumors by employing deep learning technologies. Methods: We constructed a neural network model for the automated detection of tumor tissues and blood vessels from the sequential liver ultrasound images. Faster region-based convolutional neural networks (Faster R-CNN) is employed as a base model for the object detection, which can output the detection results in 4 frames per second and enable the system to be particularly suitable for the real time ultrasonography. Moreover, we proposed a new neural network architecture feeding both the current and previous images into Faster R-CNN. For training the models, intraoperative ultrasound images obtained from one hepatocellular carcinoma (HCC) patient were used. The obtained image was a multifaceted observation of the liver and includes one HCC and some blood vessels. We labeled 91 images with the help of a liver specialist. We compared the tumor detection performance of the plain Faster R-CNN model with that of the proposed model. Results: We find that both the models performed well in detecting HCC and blood vessels, after training with 400 epochs using Adam. However, the mean precision of our model reaches 0.549, which is 0.019 better than that of the plain Faster R-CNN, and the mean sensitivity of our model about HCC reaches 0.623±0.385 for 30 scenes of sequential liver ultrasound images, which is also 0.146 better than that of the plain Faster R-CNN model. Conclusions: The comparison between the proposed model and the plain Faster R-CNN model shows that we achieved better accuracy in tumor detection, in terms of the mean precision as well as the mean sensitivity, with the proposed model.

Optimal tumor numbers in surgical candidates for multiple hepatocellular carcinomas.

BACKGROUND: According to the American Association for the Study of Liver Diseases guidelines, liver resection is not recommended for multiple hepatocellular carcinomas, although it is performed in Asian countries, including Japan. However, the maximum number, location, and recurrence types of tumors have not been reported in detail. METHODS: This retrospective study analyzed data for 1,170 patients who underwent surgical resection for hepatocellular carcinoma between October 2002 and December 2020 in a Japanese tertiary care hospital. Statistical analysis was performed to compare the surgical short-term and long-term outcomes among patients with >3 tumors and those with ≤3 tumors. RESULTS: This study of patients who underwent liver resection identified 775 who had a single tumor and compared overall survival rates with 477 who had multiple hepatocellular carcinomas: 242 had 2 hepatocellular carcinomas, 79 had 3 hepatocellular carcinomas, and 74 had >3 hepatocellular carcinomas. The median survival times based on the number of tumors were 9.74 years for a single tumor, 6.36 years for 2 tumors, 7.21 years for 3 tumors, 3.31 years for 4 tumors, and 3.48 years for 5 tumors. The median survival time was significantly worse in patients with >3 tumors than in those with 3 tumors (P < .0001). Concerning the type of treatments for recurrence, the patients who underwent surgical treatment had significantly better survival after recurrence than patients who underwent other treatments (8.32 vs 3.19 years; P < .001). CONCLUSION: The overall survival after liver resection was significantly worse for patients with >3 tumors than for those with <3 tumors. However, liver resection can be recommended for patients with 2 or 3 hepatocellular carcinomas because an acceptable median survival (>5 years) can be expected.

The impact of the covalently closed circular DNA level on recurrence of hepatocellular carcinoma after initial hepatectomy: an analysis of patients with resolved hepatitis B virus infection.

BACKGROUND: We assessed whether or not covalently closed circular DNA (cccDNA) levels in the background liver influence the recurrence of hepatocellular carcinoma (HCC) in patients with resolved hepatitis B virus (HBV) infection. METHODS: Among 425 patients who underwent initial hepatectomy for HCC between 2010 and 2018, a retrospective review was performed in 44 with resolved HBV infection. The clinicopathologic characteristics were analyzed for correlation with tumor recurrence. The HBV cccDNA levels were tested via a droplet digital polymerase chain reaction assay. RESULTS: HBV cccDNA was detected in 27 of 44 patients (61%), and the median level was 1.0 copies/1000 ng (range, 0-931.3 copies/1000 ng). Anti-HBc ≥8.9 S/CO was associated with cccDNA detection (odds ratio, 11.08; 95% confidence interval [95% CI], 2.48-49.46; P = 0.002). Twenty-eight patients (64%) developed HCC recurrence after hepatectomy. The overall 3- and 5-year recurrence-free survival rates were 45.7% and 34.3%, respectively.19 HBV cccDNA levels was not significantly associated with HCC recurrence, while the presence of multiple tumors was an independent risk fact or (hazard ratio, 6.53; 95% CI, 2.48-17.19; P < 0.001. CONCLUSION: HBV cccDNA levels did not influence HCC recurrence after hepatectomy. Anti-HBc levels may be used as a surrogate marker for cccDNA.

Conversion surgery after preoperative therapy for advanced hepatocellular carcinoma in the era of molecular targeted therapy and immune checkpoint inhibitors.

BACKGROUND: Optimal strategies for advanced hepatocellular carcinoma (HCC) tumors, such as those with vascular tumor thrombus and those with extrahepatic metastases are unclear. METHODS: A literature review was conducted focusing on conversion surgery for HCC after molecular targeted therapy and therapy using immune checkpoint inhibitors. RESULTS: Upfront surgical resection of advanced HCC tumors has been challenged at some institutions because of lack of promising therapeutic options. Preoperative transcatheter arterial chemoembolization, hepatic arterial infusion chemotherapy, and radiotherapy in patients with unresectable HCC were developed to improve long-term outcome, but the results were not promising. Nonetheless, the recent advent of molecular targeted therapies and immune check-point inhibitors, enabling frequent tumor responses, has accelerated the use of conversion surgery after these therapies in patients with initially unresectable HCC. Increasing numbers of conversion surgeries after lenvatinib therapy has been reported, and the first prospective clinical trial assessing conversion surgery after lenvatinib therapy in initially unresectable HCC has been commenced. Furthermore, the superiority of combination therapy using atezolizumab and bevacizumab over sorafenib, a conventional first-line drug for unresectable HCC, in terms of overall survival and tumor response has been demonstrated, and the use of this regimen alongside conversion surgery is expected in addition to lenvatinib. CONCLUSION: The literature demonstrated the feasibility of conversion surgery after systemic therapy. Further clinical investigation of surgery after systemic therapy for advanced HCC may be undertaken by clearly distinguishing the tumor status as technically unresectable or oncologically unresectable but technically resectable.

Efficacy and Safety of Lenvatinib for the Treatment of Recurrent Hepatocellular Carcinoma After Living Donor Liver Transplantation: A Report of Two Cases.

BACKGROUND/AIM: Recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) is one of the main causes of death after LT, and patient prognosis is reportedly poor. Herein, we report two cases of unresectable HCC recurrences after living donor LT that were treated effectively and safely with lenvatinib. CASE REPORT: Both cases underwent LT for HCC beyond the Milan criteria. About 2 years following LT, HCC recurrences were found and resected. However, unresectable 2nd-recurrences were found several months after surgery. In the first case, a complete response was maintained for 12 months with transarterial chemoembolization and lenvatinib. In the second case, a partial response was maintained for 5 months with lenvatinib. Severe adverse events were not observed in either case. CONCLUSION: The presently reported cases suggest that lenvatinib might be effective for the treatment of unresectable HCC recurrence after LT.

Risk factors for hepatitis B virus recurrence after living donor liver transplantation: A 22-year experience at a single center.

The factors associated with hepatitis B virus (HBV) recurrence after living donor liver transplantation (LDLT) have not been fully clarified. The aim of this study was to determine the risk factors associated with HBV recurrence after LDLT. From January 1996 to December 2018, a total of 609 LDLT operations were performed at our center. A retrospective review was performed of 70 patients (male, n = 59; female, n = 11; median age = 54 years) who underwent LDLT for HBV-related liver disease. The virologic and biochemical data, tumor burden, antiviral and immunosuppressive therapy were evaluated and compared between the HBV recurrence and non-recurrence groups. Eleven of 70 patients (16%) developed post-LDLT HBV recurrence. The overall actuarial rates of HBV recurrence at 1, 3, 5, 10, and 20 years were 0%, 13%, 16.7%, 18.8%, and 18.8%, respectively. The median interval between LDLT and HBV recurrence was 57 months (range, 18-124 months). Based on the univariate and multivariate analyses, a serum HBV DNA level of ≥ 4 log copies/mL (hazard ratio [HR], 4.861; 95% confidence interval [95% CI], 1.172-20.165; P = 0.029), and hepatocellular carcinoma (HCC) beyond the Milan criteria (HR, 10.083; 95% CI, 2.749-36.982; P < 0.001) were independent risk factors for HBV recurrence after LDLT. In LDLT patients, high pre-LT HBV DNA levels and HCC beyond the Milan criteria were risk factors for HBV recurrence. With the current expansion of the LT criteria for HCC, we should remain cautious regarding the risk of HBV recurrence, particularly in these groups.

Hepatitis B virus recurrence after living donor liver transplantation of anti-HBc-positive grafts: A 22-year experience at a single center.

The use of hepatitis B core antibody (anti-HBc)-positive grafts is one strategy for expanding the donor pool for liver transplantation (LT). The aim of this study was to determine the risk factors associated with hepatitis B virus (HBV) recurrence after living donor LT (LDLT) of anti-HBc-positive grafts. From January 1996 to December 2018, a total of 609 LDLT procedures were performed at our center. A retrospective review was performed for 31 patients (23 males and 8 females; median age = 47 years) who underwent LDLT for HBV-unrelated liver disease from anti-HBc-positive donors. The factors associated with HBV recurrence were evaluated and compared between the HBV recurrence and non-recurrence groups. The median follow-up period after LT was 135 months (range, 6-273 months). Four of 31 patients (12.9%) developed post-LT HBV recurrence. All four cases were HBV-naïve patients (anti-HBc-negative and Hepatitis B surface antibody-negative). The median interval between LDLT and HBV recurrence was 42 months (range, 20-51). The overall actuarial rates of HBV recurrence at 1, 3, 5, 10, and 20 years were 0%, 7.2%, 15.7%, 15.7%, and 15.7%, respectively. Although there were no significant differences between the HBV recurrence and non-recurrence groups, HBV recurrence tended to occur in HBV-naïve recipients (P = 0.093). HBV-naïve status may contribute to HBV recurrence after LDLT for HBV-unrelated liver disease from anti-HBc-positive donors. Careful monitoring for serological HBV markers is needed, particularly in this group.

Delivery of pancreatic digestive enzymes into the gastrointestinal tract by pancreatic exocrine tissue transplant.

Exocrine pancreatic insufficiency, caused by disease-induced loss of pancreatic exocrine cells, may be treated through regenerative stem cell technologies that facilitate the production of pancreatic exocrine cells from induced pluripotent stem cells (iPSCs). However, delivering the digestive enzymes produced in the transplanted cells to the gastrointestinal tract remains a challenge. To generate an allogenic transplantation rat model, minced pancreas was transplanted into the gastric submucosal space with ablation of muscularis mucosa. In the allogenic transplantation, transplanted pancreatic cells were engrafted. Elevated amylase was detected in gastric juice, while transplanted cells disappeared through auto-digestion when the muscularis mucosa was not eliminated. Human iPSCs were differentiated into pancreatic exocrine cells by stage-specific treatment with growth factors and chemical compounds, and the differentiated pancreatic cells were implanted into the gastric submucosal space of nude rats. The transplanted cells were engrafted, and amylase was detected in the gastric juice in some cases. These findings suggest that transplantation of pancreatic exocrine cells into the gastric submucosal space with muscularis mucosa elimination will contribute to a regenerative approach for pancreatic exocrine insufficiency.

Optimal diagnostic method using multidetector-row computed tomography for predicting lymph node metastasis in colorectal cancer.

BACKGROUND: Prediction of nodal involvement in colorectal cancer is an important aspect of preoperative workup to determine the necessity of preoperative treatment and the adequate extent of lymphadenectomy during surgery. This study aimed to investigate newer multidetector-row computed tomography (MDCT) findings for better predicting lymph node (LN) metastasis in colorectal cancer. METHODS: Seventy patients were enrolled in this study; all underwent MDCT prior to surgery and upfront curative resection for colorectal cancer. LNs with a short-axis diameter (SAD) ≥ 4 mm were identified on MDCT images, and the following measures were recorded by two radiologists independently: two-dimensional (2D) SAD, 2D long-axis diameter (LAD), 2D ratio of SAD to LAD, 2D CT attenuation value, three-dimensional (3D) SAD, 3D LAD, 3D SAD to LAD ratio, 3D CT attenuation value, LN volume, and presence of extranodal neoplastic spread (ENS), as defined by indistinct nodal margin, irregular capsular enhancement, or infiltration into adjacent structures. RESULTS: Forty-six patients presented 173 LNs with a SAD ≥ 4 mm, while 24 patients exhibited pathologically confirmed LN metastases. Receiver operating characteristic analysis revealed that 2D LAD was the most sensitive measure for LN metastases with an area under the curve of 0.752 (cut-off value, 7.05 mm). When combined with CT findings indicating ENS, 2D LAD (> or ≤ 7 mm) showed enhanced predictive power for LN metastases (area under the curve, 0.846; p < 0.001). CONCLUSIONS: LAD in axial MDCT imaging is the most sensitive measure for predicting colorectal LN metastases, especially when MDCT findings of ENS are observed.

Production of pancreatic progenitor cells from human induced pluripotent stem cells using a three-dimensional suspension bioreactor system.

Islet replacement is a promising strategy for the treatment of patients with type 1 diabetes and patients who have undergone total pancreatectomy. Recent progress in cellular reprogramming technology may allow the transplantation of a patient's own pancreatic cells. Although many studies have reported the differentiation of pancreatic progenitor cells from mouse and human pluripotent stem cells (PSCs), obtaining sufficient cell numbers for clinical applications remains problematic. Here, we describe the mass production of human pancreatic progenitor cells from human induced (i)PSCs using a three-dimensional suspension bioreactor system. Bioreactor culture of cells with stage-specific provision of growth factors and small compounds for 17 days produced approximately 1.6  × â€…108  cells/100 ml vessel in a single batch. About 95% of cells expressed pancreatic and duodenal homeobox factor 1, and 22% co-expressed the transcription factor NKX6.1. Furthermore, culture of pancreatic progenitor cells for an additional 2 weeks yielded mature pancreatic cells, including C-peptide-, glucagon- and trypsin-expressing cell populations. Moreover, differentiated ß-cells secreted insulin in response to increased glucose in vitro. These findings suggest that a three-dimensional suspension culture system can generate human pancreatic progenitor cells from human iPSCs. Further optimization of culture conditions should provide sufficient functional islet cells for transplantation therapy. Copyright © 2017 John Wiley & Sons, Ltd.