What is the crux of successful living-donor liver transplantation for recipients aged 70 and beyond?

Aim: There is limited evidence regarding the feasibility of living-donor liver transplantation (LDLT) for patients aged over 70. The aims of this study were to assess postoperative outcomes in elderly recipients and to ascertain the potential feasibility and acceptability of LDLT. Methods: Data were collected from 762 recipients, including 26 in the elderly group (aged ≥70) and 736 in the younger group (aged <70), and reviewed even by propensity score matching (PSM). Results: No significant differences were observed in the frequency of postoperative complications between the two groups. Additionally, both groups exhibited a comparable 30-day mortality rate after LDLT (3.9% in both) and similar hospital stays (36 days vs. 40 days). The 1-, 3-, and 5-year graft survival rates in the elderly group were 92.0%, which was comparable to those in the younger group (p = 0.517), as confirmed by PSM. Notably, all donors for elderly patients were the children of the recipients, with an average age of 41.6 years, and grafts from donors aged ≥50 years were not utilized, signifying the use of high-quality grafts. Our inclusion criterion for elderly recipients was strictly defined as an ECOG-PS score of 0-2, which played a pivotal role in achieving favorable postoperative outcomes. Conclusion: LDLT can be performed safely for elderly patients aged 70 years or older, provided they have a preserved PS and receive high-quality grafts from younger donors, inevitably all children of elderly recipients. This approach yields acceptable long-term outcomes. Consequently, age alone should not serve as an absolute contraindication for LDLT.

A Decade of Liver Transplantation in the United States: Drivers of Discard and Underutilization.

Background: Organ shortage remains a major challenge for the field of transplantation. Maximizing utilization and minimizing discard of available organs is crucial to reduce waitlist times. Our aim was to investigate the landscape of liver recovery, discard over the past decade in the United States, and identify areas to reduce organ discard. Methods: This study used the Scientific Registry of Transplant Recipients United Network for Organ Sharing database to analyze the rates and associated reasons of discarded organs from 2010 to 2021. All deceased donors were evaluated, and data were analyzed by organ type, year, and region. Organ disposition was analyzed by year and region. Donor demographics and liver biopsy data were also analyzed. Results: The volume of liver transplantation increased steadily, with a 44% increase from 2010 to 2021. Donation after circulatory death transplantation increased by 239%, comprising 10.6% of transplants in 2021, yet discard rates remained high at 30% for this donor subset. For all donor types, the liver discard rate has remained stable around 10% despite a 74% increase in available donors. Seventy percent of liver discards were attributed to organ factors, with biopsy findings accounting for 40% of all discards. Of livers that were biopsied, 70% had macrosteatosis of <30%. Conclusions: Analysis of trends in transplantation and discard allow for identifying areas of underutilization. Donation after circulatory death livers have expanded the pool of transplanted livers but remain discarded at high rates. Significant differences remain in discard rates between geographic regions. We identify several areas to lower the discard rates. The expanding role of machine perfusion may allow for utilization of previously discarded organs.

Improved outcomes of liver resection for hepatitis C-related hepatocellular carcinoma after the introduction of direct-acting antiviral therapy.

BACKGROUND: Assess impact of direct-acting antivirals introduction on outcomes after liver resection for hepatocellular carcinoma. METHODS: 391 patients (1991-2021) treated with resection for hepatocellular carcinoma on Hepatitis C background were divided according to receiving Hepatitis C treatment, treatment type, achievement of sustained virological response (SVR), time of resection pre- (Era 1, 1991-2011) and post-direct acting antivirals introduction (Era 2, 2012-2021). Survival was estimated with Kaplan-Meier curves, Cox regression analysis performed to identify survival predictors. RESULTS: Majority of patients had single lesion (67.8%), diameter >2 cm in 60.6%, no evidence of macroscopic vascular invasion on imaging. Pathology showed vascular invasion in 69.6% of patients, 76.5% microvascular. Recurrence developed in 247 patients (63.2%). 194 patients (49.6%) achieved SVR. Overall survival at 1-, 3-, 5-years was 94.6%, 85.7%, 78.8% for patients who achieved SVR, 80.1%, 48.1%, 29.9% in those who did not (p < 0.001). 220 patients (56.3%) were in Era 1, 171 (43.7%) in Era 2. Survival at 1-, 3-, 5-years was 76.1%, 49%, 36% in Era 1, 94.5%, 82.5%, 70.3% in Era 2 (p < 0.001). SVR was an independent predictor of survival on multiple Cox Regression analysis. CONCLUSION: While many aspects of HCC management have evolved, SVR following direct-acting antivirals independently improves HCC resection outcomes.

Validation of Japanese indication criteria for deceased donor liver transplantation for hepatocellular carcinoma: Analysis of US national registry data.

AIM: The Japanese indication criteria for liver transplantation (LT) for hepatocellular carcinoma (HCC) have been updated based on living donor LT data to include either the Milan criteria (MC) or the 5-5-500 rule, which requires a nodule size of ≤5 cm, ≤5 nodules, and an alpha-fetoprotein (AFP) level ≤500 ng/mL. We aimed to validate the 5-5-500 rule and the MC for deceased donor LT (DDLT). METHODS: Using national registry data from the United States from 2010 to 2014, we separated DDLT patients into four groups based on the MC and the 5-5-500 rule. The AFP values were stratified into categories: ≤100, 101-300, 301-500, and >500 ng/mL. RESULTS: The 5-year survival rate was significantly lower for patients in the groups within MC/beyond 5-5-500 (56.3%) or beyond MC/5-5-500 (60.7%) than for patients in the groups within MC/5-5-500 (76.2%) and beyond MC/within 5-5-500 (72.3%) (p < 0.01). Hepatocellular carcinoma recurrence at 5 years was highest for the within MC/beyond 5-5-500 (25.4%) group, followed by the beyond MC/within 5-5-500 (13.1%), beyond MC/5-5-500 (9.6%), and within MC/5-5-500 (7.4%) groups. The stratified 5-year survival rates after DDLT were 76.5%, 72.4%, 58.4%, and 55.6% in the AFP ≤100, 101-300, 301-500, and >500 categories, respectively (p < 0.01). CONCLUSION: The 5-5-500 rule guides the appropriate selection of patients with HCC for DDLT. Patients with AFP levels from 300 to 500 ng/mL had inferior outcomes even when they met the 5-5-500 rule, so further investigation is needed to guide their treatment.

Impact of albumin-lymphocyte-platelet-C-reactive protein index as a prognostic indicator of hepatocellular carcinoma after resection: Associated with nuclear factor erythroid 2-related factor 2.

AIM: To investigate the prognostic value of the preoperative albumin-lymphocyte-platelet-C-reactive protein (ALPC) index in patients with hepatocellular carcinoma (HCC) undergoing curative hepatectomy. We also evaluated the relationship between the ALPC index and the phosphorylated nuclear factor erythroid 2-related factor 2 (p-Nrf2) levels. METHODS: Data were analyzed retrospectively from 256 patients who underwent resection for HCC. For cross-validation, patients were divided into the training and testing cohort. We assessed eight combinations of inflammatory markers for predictive value for recurrence. We examined the associations of the ALPC index with recurrence-free survival and overall survival in univariate and multivariate analyses (Cox proportional hazards model). Immunohistochemical staining of p-Nrf2 was performed on tumor samples of 317 patients who underwent hepatic resection for HCC. RESULTS: A high preoperative ALPC index correlated with a high serum albumin concentration, small tumor size, low rate of poor differentiation, solitary tumor, early Barcelona Clinic Liver Cancer stage, and low rate of microscopic intrahepatic metastasis in the training dataset. A high preoperative ALPC index correlated with a high serum albumin concentration, high serum alpha-fetoprotein concentration, small tumor size, a low rate of poor differentiation and a low rate of microscopic intrahepatic metastasis in the testing dataset. A higher preoperative ALPC index was an independent predictor of longer recurrence-free survival and overall survival in the training and testing datasets. A high ALPC index was associated with negative p-Nrf2 expression in HCC tumor cells. CONCLUSIONS: We showed that a high ALPC index was an independent prognostic factor for patients with HCC undergoing curative hepatic resection.

The learning curve of liver procurement from donation after circulatory death donor.

PURPOSE: This study aimed to evaluate the learning curve for donation after circulatory death (DCD) liver procurement. METHODS: DCD liver procurements performed by a single surgeon (n = 36) were separated into two phases: the learning and established phases. RESULTS: A cumulative sum analysis using the operative donor warm ischemia time (oWIT) and donor hepatectomy time (dHT) showed that ten and seven cases, respectively, were needed for stable surgical procedures. The established phase (n = 26, since Case 11) was likely to have a shorter oWIT (p = 0.06; 7.5 min vs. 9 min) and dHT (p = 0.09; 32 min vs. 37 min) than the learning phase. While the hospital stay was significantly shorter and donor age was older in the established phase (p = 0.04 and p < 0.01; 12 days vs. 41 days and 38 years vs. 24 years, respectively), the incidence rates of post-transplant complications such as early allograft dysfunction (p = 0.74) and vascular complications (p = 0.53) were similar. CONCLUSIONS: The learning curve for DCD liver procurement demonstrated that 10 cases were required to establish these techniques. The oWIT and dHT for DCD liver procurement can represent markers of operative efficiency.

Breaking distance barriers in liver transplantation: Risk factors and outcomes of long-distance liver grafts.

BACKGROUND: Long-distance-traveling liver grafts in liver transplantation present challenges due to prolonged cold ischemic time and increased risk of ischemia-reperfusion injury. We identified long-distance-traveling liver graft donor and recipient characteristics and risk factors associated with long-distance-traveling liver graft use. METHODS: We conducted a retrospective analysis of data from donor liver transplantation patients registered from 2014 to 2020 in the United Network for Organ Sharing registry database. Donor, recipient, and transplant factors of graft survival were compared between short-travel grafts and long-distance-traveling liver grafts (traveled >500 miles). RESULTS: During the study period, 28,265 patients received a donation after brainstem death liver transplantation and 3,250 a donation after circulatory death liver transplantation. The long-distance-traveling liver graft rate was 6.2% in donation after brainstem death liver transplantation and 7.1% in donation after circulatory death liver transplantation. The 90-day graft survival rates were significantly worse for long-distance-traveling liver grafts (donation after brainstem death: 95.7% vs 94.5%, donation after circulatory death: 94.5% vs 93.9%). The 3-year graft survival rates were similar for long-distance-traveling liver grafts (donation after brainstem death: 85.5% vs 85.1%, donation after circulatory death: 81.0% vs 80.4%). Cubic spline regression analyses revealed that travel distance did not linearly worsen the prognosis of 3-year graft survival. On the other hand, younger donor age, lower donor body mass index, and shorter cold ischemic time mitigated the negative impact of 90-day graft survival in long-distance-traveling liver grafts. CONCLUSION: The use of long-distance-traveling liver grafts negatively impacts 90-day graft survival but not 3-year graft survival. Moreover, long-distance-traveling liver grafts are more feasible with appropriate donor and recipient factors offsetting the extended cold ischemic time. Mechanical perfusion can improve long-distance-traveling liver graft use. Enhanced collaboration between organ procurement organizations and transplant centers and optimized transportation systems are essential for increasing long-distance-traveling liver graft use, ultimately expanding the donor pool.

Outcomes of Simultaneous Heart and Kidney Transplantation.

BACKGROUND: Simultaneous heart-kidney transplantation has been increasingly performed in end-stage heart failure patients with concurrent kidney dysfunction despite limited evidence supporting its indications and utility. OBJECTIVES: The purpose of this study was to investigate the effects and utility of simultaneously implanted kidney allografts with various degrees of kidney dysfunction during heart transplantation. METHODS: Using the United Network for Organ Sharing registry, long-term mortality was compared in recipients with kidney dysfunction who underwent heart-kidney transplantation (n = 1,124) vs isolated heart transplantation (n = 12,415) in the United States between 2005 and 2018. In heart-kidney recipients, contralateral kidney recipients were compared for allograft loss. Multivariable Cox regression was used for risk adjustment. RESULTS: Long-term mortality was lower among heart-kidney recipients than among heart-alone recipients when recipients were on dialysis (26.7% vs 38.6% at 5 years; HR: 0.72; 95% CI: 0.58-0.89) or had a glomerular filtration rate (GFR) of <30 mL/min/1.73 m2 (19.3% vs 32.4%; HR: 0.62; 95% CI: 0.46-0.82) and GFR of 30 to 45 mL/min/1.73 m2 (16.2% vs 24.3%; HR: 0.68; 95% CI: 0.48-0.97) but not in GFR of 45 to 60 mL/min/1.73 m2. Interaction analysis showed that the mortality benefit of heart-kidney transplantation continued up to GFR 40 mL/min/1.73 m2. The incidence of kidney allograft loss was higher among heart-kidney recipients than among contralateral kidney recipients (14.7% vs 4.5% at 1 year; HR: 1.7; 95% CI: 1.4-2.1). CONCLUSIONS: Heart-kidney transplantation relative to heart transplantation alone provided superior survival for dialysis-dependent recipients and non-dialysis-dependent recipients up to a GFR of approximately 40 mL/min/1.73 m2 but at the cost of almost twice the risk of kidney allograft loss than contralateral kidney allograft recipients.

The Importance of Segment 4 Anatomy on Outcomes Following Living Donor Left Lateral Segmentectomy.

BACKGROUND: During left lateral section (LLS) resection for live liver donation, the vascular inflow and the bile drainage of segment 4 (S4) are compromised. We investigated the long-term changes of S4 after donation and their potential prognostic impact on living liver donors. MATERIALS AND METHODS: This was a retrospective analysis of 42 consecutive left lateral (LLS, S2/3) liver resections for living donation. RESULTS: There were 25 female and 17 male donors. Median age was 33 y and median body mass index was 26. Median LLS, S2/3, volume was 262 cc, and median sS4 volume was 160 cc. Complications were encountered in three donors (7%). An independent extrahepatic S4 artery (S4A) (with a proximal left heptic artery or a right hepatic artery origin) was identified in 41% of the donors. Ligation of the independent S4A was not associated with the rate of post resection liver dysfunction, complications, or the degree of S4 atrophy. Having a dominant S4 portal triad pedicle feeding the right anterior sectors, segment 5/8, of the liver was associated with increased parenchymal damage as evidenced by a higher peak of alanine aminotransferase but was not associated with postoperative complications. The median degree of atrophy of S4 at 1 y post donation as noted on imaging was 66%. The presence of a dominant S4 portal triad pedicle and the peak alanine aminotransferase early postoperatively were both predictors of the degree of S4 atrophy post donation. CONCLUSIONS: The presence of an independent S4A or dominant S4 portal triad pedicle feeding the liver right anterior sectors, segment 5/8, should not be a contraindication for left lateral segment living donation.

Radiological and pathological assessment with EOB-MRI after Y90 radiation lobectomy prior to liver resection for hepatocellular carcinoma.

BACKGROUND: Radiation lobectomy (RL) utilizes Yttrium-90 (Y90) radioembolization for achieving tumor control and inducing contralateral lobe hypertrophy. Our objective was to evaluate the chronological changes occurring radiologically and histopathologically after Y90 RL. METHODS: We retrospectively reviewed 22 patients with chronic liver disease who underwent Y90 RL prior to planned liver resection for hepatocellular carcinoma. Gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) enhanced magnetic resonance imaging (EOB-MRI) was performed every 3 months. RESULTS: Future liver remnant volume (FLRV) significantly increased up to 9 months after Y90 RL. Gd-EOB-DTPA uptake in the treated lobe experienced a 40% reduction in enhancement ratio (ER) during ensuing first 3 months, and never recovered. The reduced ER in the non-tumoral parenchyma was significantly correlated with increased FLRV and FLR (r = 0.41 and r = 0.35, respectively; both p < 0.01). Histopathological evaluation of non-tumor liver tissue found features of sinusoidal obstruction syndrome as an early change after Y90 RL (median 5.7 months) and parenchymal collapse as a late change (mean 11 months). DISCUSSION: The reduced uptake of Gd-EOB-DTPA at 3 months post Y90 RL correlates with a significant increase in FLRV prior to liver resection. EOB-MRI evaluation at 3 months can guide future plan of action after Y90 RL.

Recurrent Intrahepatic Cholangiocarcinoma - Review.

Intrahepatic cholangiocarcinoma (ICC) is the second-most common primary liver malignancy after hepatocellular carcinoma. While surgical resection with negative margin is the only curative treatment, ICC has very high rate of recurrence, up to 60-70% after curative resection. We reviewed the current data available on risk factors for ICC recurrence, recurrence pattern (location and timing), treatment options, and future directions. The risk factors for recurrence include elevated preoperative CA19-9, presence of liver cirrhosis, nodal metastasis, positive margins, and vascular invasion. Understanding different recurrence patterns, timing course, and risk factors for early recurrence is important to tailor postoperative surveillance and select treatment strategies including systemic or locoregional therapy. Re-resection can be considered for a selected patient population at experienced centers, and can yield long-term survival. ICC remains a dismal disease given the high likelihood of recurrence. Advances in our understanding of the genomic landscape of ICC are beginning to identify targetable alterations in ICC in subsets of patients that allow for personalized treatment.

A comparative study of portal vein embolization versus radiation lobectomy with Yttrium-90 micropheres in preparation for liver resection for initially unresectable hepatocellular carcinoma.

BACKGROUND: Portal vein embolization before liver resection is considered the therapy of choice for patients with inadequate future liver remnants. The concept of radioembolization with Yttrium-90 to achieve the same goal has limited data. METHODS: We retrospectively compared patients who underwent portal vein embolization and Yttrium-90 lobectomy before resection of hepatocellular carcinoma in patients with chronic liver disease. RESULTS: Seventy-three patients underwent portal vein embolization and 22 patients underwent Yttrium-90. Forty-seven percent of patients before portal vein embolization required additional procedures for tumor control, and 27% of patients after Yttrium-90 required additional procedure to mainly induce further hypertrophy. Both therapies achieved the goal of future liver remnants >40%, but the degree of hypertrophy was significantly higher in Yttrium-90 patients (63% for Yttrium-90, 36% for portal vein embolization, P < .01). Tumor response was significantly better with Yttrium-90, achieving complete response in 50% of patients. Resectability rate was higher after portal vein embolization (85% for portal vein embolization, 64% for Yttrium-90, P = .03). Tumor progression was the most common reason precluding surgery. Complete tumor control was the reason not to pursue surgery in 18% of patients after Yttrium-90. CONCLUSION: Both preoperative portal vein embolization and Yttrium-90, increases liver resectability rates by inducing hypertrophy of future liver remnants in patients with hepatocellular carcinoma and chronic liver disease. Yttrium-90 lobectomy achieved better tumor control and provided more time to assess therapy response, optimizing the indication for surgery.

Surgical Treatments of Hepatobiliary Cancers.

Hepatobiliary cancers which include hepatocellular carcinoma (HCC) and biliary tract cancers (i.e., cholangiocarcinoma and gallbladder carcinoma) are associated with significant morbidity and mortality based on the stage of the disease at presentation. With improved screening for hepatobiliary malignancies in patients with risk factors and with widespread use of laparoscopic cholecystectomy, hepatobiliary malignancies, including incidental diagnosis of gallbladder carcinoma, are on the rise. Definitive treatment of hepatobiliary malignancies include surgical resection, ablation, and liver transplantation. However, management of these cancers is challenging due to the complex hepatobiliary anatomy and the need for meticulous perioperative management especially in patients with advanced liver disease. The management and prognosis of hepatobiliary malignancies vary widely based on the stage of presentation, with surgical options providing the possibility of definitive cure in patients presenting with early-stage disease. Surgical resection for HCC results in good outcomes if performed in ideal candidates. For patients with early HCC who are not candidates for surgical resection, ablation and liver transplantation should be considered. Similarly, surgical resection is also the definitive treatment for biliary tract cancers, and liver transplantation can be curative in selected patients with perihilar cholangiocarcinoma after neoadjuvant chemoradiotherapy. The role of routine adjuvant chemotherapy and radiotherapy is not clearly established, but adjuvant therapies can offer better outcomes in patients with advanced disease at presentation. Outcomes of surgical management of hepatobiliary cancers seem to be improving. Given the complex decision-making process involved, multidisciplinary evaluation is essential to provide and coordinate the best treatments for these patients.

Living Donor Nephrectomy Using a Right Malrotated Kidney: A Case Report.

A 46-year-old woman was approved as a living kidney donor in our center for paired donation working with the National Kidney Registry. The imaging revealed a malrotated right kidney with the hilum oriented cephalad. We selected that kidney for donation, and an uneventful laparoscopic donor nephrectomy was performed. To our knowledge, this is the first case of laparoscopic living donor nephrectomy using a sagittally malrotated kidney.

Mac-2 binding protein glycan isomer (M2BPGi) is a new serum biomarker for assessing liver fibrosis: more than a biomarker of liver fibrosis.

Assessing liver fibrosis is important for predicting the efficacy of antiviral therapy and patient prognosis. Liver biopsy is the gold standard for diagnosing liver fibrosis, despite its invasiveness and problematic diagnostic accuracy. Although noninvasive techniques to assess liver fibrosis are becoming important, reliable serum surrogate markers are not available. A glycoproteomics study aimed at identifying such markers discovered Mac 2-Binding Protein Gylcan Isomer (M2BPGi), which is a reliable marker for assessing liver fibrosis in patients with viral hepatitis and other fibrotic liver diseases such as primary biliary cholangitis, biliary atresia, autoimmune hepatitis, and nonalcoholic fatty liver disease. M2BPGi predicts the development of hepatocellular carcinoma (HCC) in patients infected with hepatitis B and C as well as the prognosis of liver cirrhosis in those with HCC after therapy. The unique features of M2BPGi are as follows: (1) cut-off values differ for the same stages of fibrosis according to the cause of fibrosis; and (2) M2BPGi levels rapidly decrease after patients achieve a sustained antiviral response to hepatitis C virus. These observations cannot be explained if M2BPGi levels reflect the amount of fibrotic tissue. Hepatic stellate cells (HSCs) secrete M2BPGi, which may serve as a messenger between HSCs and Kupffer cells via Mac-2 (galectin 3) that is expressed in Kupffer cells during fibrosis progression. Here we show that M2BPGi is a surrogate marker for assessing HSC activation. These findings may reveal the roles of HSCs in extrahepatic fibrotic disease progression.

Altered Expression of Hippo Signaling Pathway Molecules in Intrahepatic Cholangiocarcinoma.

OBJECTIVE: MOB1, a core component of the Hippo signaling pathway, suppresses cell proliferation, and MOB1 liver conditional knockout mice develop intrahepatic cholangiocarcinoma (ICC). However, its clinical significance in human ICC has not been established. The aim of this study was to characterize protein levels and the role of Hippo and TGF pathways in ICCs. METHODS: The protein levels of yes-associated protein 1 (YAP1), MOB1, Smad2, and TGFß2 in 88 ICC cases were analyzed. Protein level was graded by a scoring system; then, the clinicopathological factors, including prognosis, were analyzed based on protein level. RESULTS: Nuclear overexpression of YAP1 was seen in 28 cases (31.8%), and it was significantly associated with a poor overall survival rate (p = 0.01). MOB1 expression decreased in 42 cases (47.7%) and was associated with a poor overall survival rate (p = 0.02). SMAD2 nuclear localization was significantly correlated with a high YAP1 level independent of TGFß2. Multivariate analysis revealed that a high YAP1 level, a low MOB1 level, and lymphatic permeation were independent risk factors for overall survival. CONCLUSIONS: These results showed that key components of the Hippo signaling pathway are aberrantly expressed and associated with the malignant potential of human ICC.

Hepatic stellate cells secreting WFA+ -M2BP: Its role in biological interactions with Kupffer cells.

BACKGROUND AND AIM: Hepatic stellate cells (HSCs) play a central role in hepatic fibrosis and are regulated by Kupffer cells (KCs). Wisteria floribunda agglutinin-positive Mac-2 binding protein (WFA+ -M2BP) was recently identified as a serum marker for hepatic fibrosis. Although WFA+ -M2BP was identified as a ligand of Mac-2, the function of WFA+ -M2BP in hepatic fibrosis remains unclear. METHODS: Liver specimens were obtained from five patients with cirrhosis, five with chronic hepatitis, and five without hepatic fibrosis. WFA+ -M2BP kinetics were evaluated histologically and in subpopulations of liver cells such as HSCs, KCs, endothelial cells, biliary epithelial cells, and hepatocytes in in vitro culture. The function of WFA+ -M2BP in activated HSCs was evaluated using immunoblot analysis. RESULTS: Numbers of WFA+ -M2BP-positive cells in liver tissues increased with fibrosis stage. There were significant differences in WFA+ -M2BP levels between fibrosis stages F0 and F1-2 (P = 0.012) and between fibrosis stages F1-2 and F3-4 (P < 0.001). HSCs were the source of WFA+ -M2BP secretion in in vitro cultures of liver cells, as determined by sandwich immunoassay. Cells of the human HSC line LX-2 also secreted WFA+ -M2BP. Histologically, tissue sections showed that WFA+ -M2BP was located in Mac-2-expressing KCs. In vitro assays showed that exogenous WFA+ -M2BP stimulation enhanced Mac-2 expression in KCs and that HSCs co-cultured with KCs increased α-smooth muscle actin expression. Finally, Mac-2-depleted KCs with short interfering RNA had reduced α-smooth muscle actin expression following co-culturing with HSCs. CONCLUSIONS: WFA+ -M2BP from HSCs induces Mac-2 expression in KCs, which in turn activates HSCs to be fibrogenic.

Hydrophobic bile acids suppress expression of AE2 in biliary epithelial cells and induce bile duct inflammation in primary biliary cholangitis.

Understanding the mechanisms of chronic inflammation in primary biliary cholangitis (PBC) is essential for successful treatment. Earlier work has demonstrated that patients with PBC have reduced expression of the anion exchanger 2 (AE2) on biliary epithelial cells (BEC) and deletion of AE2 gene has led to a PBC-like disorder in mice. To directly address the role of AE2 in preventing PBC pathogenesis, we took advantage of our ability to isolate human BEC and autologous splenic mononuclear cells (SMC). We studied the influence of hydrophobic bile acids, in particular, glycochenodeoxycholic acid (GCDC), on AE2 expression in BEC and the subsequent impact on the phenotypes of BEC and local inflammatory responses. We demonstrate herein that GCDC reduces AE2 expression in BEC through induction of reactive oxygen species (ROS), which enhances senescence of BEC. In addition, a reduction of AE2 levels by either GCDC or another AE2 inhibitor upregulates expression of CD40 and HLA-DR as well as production of IL-6, IL-8 and CXCL10 from BEC in response to toll like receptor ligands, an effect suppressed by inhibition of ROS. Importantly, reduced AE2 expression enhances the migration of autologous splenic mononuclear cells (SMC) towards BEC. In conclusion, our data highlight a key functional role of AE2 in the maintenance of the normal physiology of BEC and the pathogenic consequences of reduced AE2 expression, including abnormal intrinsic characteristics of BEC and their production of signal molecules that lead to the chronic inflammatory responses in small bile ducts.