Protein arginine methyl transferase 1- and Jumonji C domain-containing protein 6-dependent arginine methylation regulate hepatocyte nuclear factor 4 alpha expression and hepatocyte proliferation in mice.

Alcohol is a well-established risk factor for hepatocellular carcinoma (HCC), but the mechanisms by which it promotes liver cancer are not well understood. Several studies have shown that cellular protein arginine methylation is inhibited by alcohol. Arginine methylation is controlled by the reciprocal activity of protein arginine methyltransferases, primarily protein arginine methyl transferase 1 (PRMT1), and a demethylase Jumonji C domain-containing protein 6 (JMJD6). The aim of this study was to explore the role of arginine methylation changes in alcohol pathogenesis. We found that PRMT1 activity is inhibited in livers of mice fed with alcohol compared to pair-fed mice. Using hepatocyte-specific PRMT1 knockout mice, we identified that loss of PRMT1 results in enhanced hepatocyte proliferation and a 33% increase in liver size. This increased hepatocyte proliferation was associated with reduced expression of hepatocyte nuclear factor 4 alpha (Hnf4α), an important regulator of liver tumorigenesis. We found that PRMT1 regulates Hnf4α expression directly through arginine methylation at the (Hnf4α) promoter. In the absence of PRMT1, JMJD6 can demethylate the Hnf4α promoter and suppress its expression. We were able to restore Hnf4α expression and abolish the increase in hepatocyte proliferation by knockdown of JMJD6 in PRMT1 knockout mice. Knockdown of JMJD6 in alcohol-fed mice similarly increased Hnf4α expression. We then examined whether loss of arginine methylation might play a role in alcohol-associated liver cancers. We examined 25 human HCC specimens and found a strong correlation (R = 0.8; P < 0.01) between arginine methylation levels and Hnf4α expression in these specimens, suggesting that the above mechanism is relevant in patients. CONCLUSION: Taken together, these data suggest that PRMT1 inhibition, such as induced by alcohol, may result in epigenetic changes leading to loss of Hnf4α. This effect may contribute to alcohol's ability to promote liver tumors. (Hepatology 2018;67:1109-1126).

Arginine methylation regulates c-Myc-dependent transcription by altering promoter recruitment of the acetyltransferase p300.

Protein arginine methyltransferase 1 (PRMT1) is an essential enzyme controlling about 85% of the total cellular arginine methylation in proteins. We have shown previously that PRMT1 is an important regulator of innate immune responses and that it is required for M2 macrophage differentiation. c-Myc is a transcription factor that is critical in regulating cell proliferation and also regulates the M2 transcriptional program in macrophages. Here, we sought to determine whether c-Myc in myeloid cells is regulated by PRMT1-dependent arginine methylation. We found that PRMT1 activity was necessary for c-Myc binding to the acetyltransferase p300. PRMT1 inhibition decreased p300 recruitment to c-Myc target promoters and increased histone deacetylase 1 (HDAC1) recruitment, thereby decreasing transcription at these sites. Moreover, PRMT1 inhibition blocked c-Myc-mediated induction of several of its target genes, including peroxisome proliferator-activated receptor γ (PPARG) and mannose receptor C-type 1 (MRC1), suggesting that PRMT1 is necessary for c-Myc function in M2 macrophage differentiation. Of note, in primary human blood monocytes, p300-c-Myc binding was strongly correlated with PRMT1 expression, and in liver sections, PRMT1, c-Myc, and M2 macrophage levels were strongly correlated with each other. Both PRMT1 levels and M2 macrophage numbers were significantly lower in livers from individuals with a history of spontaneous bacterial peritonitis, known to have defective cellular immunity. In conclusion, our findings demonstrate that PRMT1 is an important regulator of c-Myc function in myeloid cells. PRMT1 loss in individuals with cirrhosis may contribute to their immune defects.

Abundance of Phase 1 and 2 Drug-Metabolizing Enzymes in Alcoholic and Hepatitis C Cirrhotic Livers: A Quantitative Targeted Proteomics Study.

To predict the impact of liver cirrhosis on hepatic drug clearance using physiologically based pharmacokinetic (PBPK) modeling, we compared the protein abundance of various phase 1 and phase 2 drug-metabolizing enzymes (DMEs) in S9 fractions of alcoholic (n = 27) or hepatitis C (HCV, n = 30) cirrhotic versus noncirrhotic (control) livers (n = 25). The S9 total protein content was significantly lower in alcoholic or HCV cirrhotic versus control livers (i.e., 38.3 ± 8.3, 32.3 ± 12.8, vs. 51.1 ± 20.7 mg/g liver, respectively). In general, alcoholic cirrhosis was associated with a larger decrease in the DME abundance than HCV cirrhosis; however, only the abundance of UGT1A4, alcohol dehydrogenase (ADH)1A, and ADH1B was significantly lower in alcoholic versus HCV cirrhotic livers. When normalized to per gram of tissue, the abundance of nine DMEs (UGT1A6, UGT1A4, CYP3A4, UGT2B7, CYP1A2, ADH1A, ADH1B, aldehyde oxidase (AOX)1, and carboxylesterase (CES)1) in alcoholic cirrhosis and five DMEs (UGT1A6, UGT1A4, CYP3A4, UGT2B7, and CYP1A2) in HCV cirrhosis was <25% of that in control livers. The abundance of most DMEs in cirrhotic livers was 25% to 50% of control livers. CES2 abundance was not affected by cirrhosis. Integration of UGT2B7 abundance in cirrhotic livers into the liver cirrhosis (Child Pugh C) model of Simcyp improved the prediction of zidovudine and morphine PK in subjects with Child Pugh C liver cirrhosis. These data demonstrate that protein abundance data, combined with PBPK modeling and simulation, can be a powerful tool to predict drug disposition in special populations.

Functional coupling of ATP-binding cassette transporter Abcb6 to cytochrome P450 expression and activity in liver.

Although endogenous mechanisms that negatively regulate cytochrome P450 (P450) monooxygenases in response to physiological and pathophysiological signals are not well understood, they are thought to result from alterations in the level of endogenous metabolites, involved in maintaining homeostasis. Here we show that homeostatic changes in hepatic metabolite profile in Abcb6 (mitochondrial ATP-binding cassette transporter B6) deficiency results in suppression of a specific subset of hepatic P450 activity. Abcb6 null mice are more susceptible to pentobarbital-induced sleep and zoxazolamine-induced paralysis, secondary to decreased expression and activity of Cyp3a11 and Cyp2b10. The knock-out mice also show decrease in both basal and xeno-inducible expression and activity of a subset of hepatic P450s that appear to be related to changes in hepatic metabolite profile. These data, together with the observation that liver extracts from Abcb6-deficient mice suppress P450 expression in human primary hepatocytes, suggest that this mouse model may provide an opportunity to understand the physiological signals and the mechanisms involved in negative regulation of P450s.

Transporter Expression in Liver Tissue from Subjects with Alcoholic or Hepatitis C Cirrhosis Quantified by Targeted Quantitative Proteomics.

Although data are available on the change of expression/activity of drug-metabolizing enzymes in liver cirrhosis patients, corresponding data on transporter protein expression are not available. Therefore, using quantitative targeted proteomics, we compared our previous data on noncirrhotic control livers (n = 36) with the protein expression of major hepatobiliary transporters, breast cancer resistance protein (BCRP), bile salt export pump (BSEP), multidrug and toxin extrusion protein 1 (MATE1), multidrug resistance-associated protein (MRP)2, MRP3, MRP4, sodium taurocholate-cotransporting polypeptide (NTCP), organic anion-transporting polypeptides (OATP)1B1, 1B3, 2B1, organic cation transporter 1 (OCT1), and P-glycoprotein (P-gp) in alcoholic (n = 27) and hepatitis C cirrhosis (n = 30) livers. Compared with control livers, the yield of membrane protein from alcoholic and hepatitis C cirrhosis livers was significantly reduced by 56 and 67%, respectively. The impact of liver cirrhosis on transporter protein expression was transporter-dependent. Generally, reduced protein expression (per gram of liver) was found in alcoholic cirrhosis livers versus control livers, with the exception that the expression of MRP3 was increased, whereas no change was observed for MATE1, MRP2, OATP2B1, and P-gp. In contrast, the impact of hepatitis C cirrhosis on protein expression of transporters (per gram of liver) was diverse, showing an increase (MATE1), decrease (BSEP, MRP2, NTCP, OATP1B3, OCT1, and P-gp), or no change (BCRP, MRP3, OATP1B1, and 2B1). The expression of hepatobiliary transporter protein differed in different diseases (alcoholic versus hepatitis C cirrhosis). Finally, incorporation of protein expression of OATP1B1 in alcoholic cirrhosis into the Simcyp physiologically based pharmacokinetics cirrhosis module improved prediction of the disposition of repaglinide in liver cirrhosis patients. These transporter expression data will be useful in the future to predict transporter-mediated drug disposition in liver cirrhosis patients.

Mitochondrial protein adducts formation and mitochondrial dysfunction during N-acetyl-m-aminophenol (AMAP)-induced hepatotoxicity in primary human hepatocytes.

3'-Hydroxyacetanilide orN-acetyl-meta-aminophenol (AMAP) is generally regarded as a non-hepatotoxic analog of acetaminophen (APAP). Previous studies demonstrated the absence of toxicity after AMAP in mice, hamsters, primary mouse hepatocytes and several cell lines. In contrast, experiments with liver slices suggested that it may be toxic to human hepatocytes; however, the mechanism of toxicity is unclear. To explore this,we treated primary human hepatocytes (PHH) with AMAP or APAP for up to 48 h and measured several parameters to assess metabolism and injury. Although less toxic than APAP, AMAP dose-dependently triggered cell death in PHH as indicated by alanine aminotransferase (ALT) release and propidium iodide (PI) staining. Similar to APAP, AMAP also significantly depleted glutathione (GSH) in PHH and caused mitochondrial damage as indicated by glutamate dehydrogenase (GDH) release and the JC-1 assay. However, unlike APAP, AMAP treatment did not cause relevant c-jun-N-terminal kinase (JNK) activation in the cytosol or phospho-JNK translocation to mitochondria. To compare, AMAP toxicity was assessed in primary mouse hepatocytes (PMH). No cytotoxicity was observed as indicated by the lack of lactate dehydrogenase release and no PI staining. Furthermore, there was no GSH depletion or mitochondrial dysfunction after AMAP treatment in PMH. Immunoblotting for arylated proteins suggested that AMAP treatment caused extensive mitochondrial protein adduct formation in PHH but not in PMH. In conclusion, AMAP is hepatotoxic in PHH and the mechanism involves the formation of mitochondrial protein adducts and mitochondrial dysfunction.

Bile acid-induced necrosis in primary human hepatocytes and in patients with obstructive cholestasis.

Accumulation of bile acids is a major mediator of cholestatic liver injury. Recent studies indicate bile acid composition between humans and rodents is dramatically different, as humans have a higher percent of glycine conjugated bile acids and increased chenodeoxycholate content, which increases the hydrophobicity index of bile acids. This increase may lead to direct toxicity that kills hepatocytes, and promotes inflammation. To address this issue, this study assessed how pathophysiological concentrations of bile acids measured in cholestatic patients affected primary human hepatocytes. Individual bile acid levels were determined in serum and bile by UPLC/QTOFMS in patients with extrahepatic cholestasis with, or without, concurrent increases in serum transaminases. Bile acid levels increased in serum of patients with liver injury, while biliary levels decreased, implicating infarction of the biliary tracts. To assess bile acid-induced toxicity in man, primary human hepatocytes were treated with relevant concentrations, derived from patient data, of the model bile acid glycochenodeoxycholic acid (GCDC). Treatment with GCDC resulted in necrosis with no increase in apoptotic parameters. This was recapitulated by treatment with biliary bile acid concentrations, but not serum concentrations. Marked elevations in serum full-length cytokeratin-18, high mobility group box 1 protein (HMGB1), and acetylated HMGB1 confirmed inflammatory necrosis in injured patients; only modest elevations in caspase-cleaved cytokeratin-18 were observed. These data suggest human hepatocytes are more resistant to human-relevant bile acids than rodent hepatocytes, and die through necrosis when exposed to bile acids. These mechanisms of cholestasis in humans are fundamentally different to mechanisms observed in rodent models.

Mechanisms of acetaminophen-induced cell death in primary human hepatocytes.

UNLABELLED: Acetaminophen (APAP) overdose is the most prevalent cause of drug-induced liver injury in western countries. Numerous studies have been conducted to investigate the mechanisms of injury after APAP overdose in various animal models; however, the importance of these mechanisms for humans remains unclear. Here we investigated APAP hepatotoxicity using freshly isolated primary human hepatocytes (PHH) from either donor livers or liver resections. PHH were exposed to 5mM, 10mM or 20mM APAP over a period of 48 h and multiple parameters were assessed. APAP dose-dependently induced significant hepatocyte necrosis starting from 24h, which correlated with the clinical onset of human liver injury after APAP overdose. Interestingly, cellular glutathione was depleted rapidly during the first 3h. APAP also resulted in early formation of APAP-protein adducts (measured in whole cell lysate and in mitochondria) and mitochondrial dysfunction, indicated by the loss of mitochondrial membrane potential after 12h. Furthermore, APAP time-dependently triggered c-Jun N-terminal kinase (JNK) activation in the cytosol and translocation of phospho-JNK to the mitochondria. Both co-treatment and post-treatment (3h) with the JNK inhibitor SP600125 reduced JNK activation and significantly attenuated cell death at 24h and 48h after APAP. The clinical antidote N-acetylcysteine offered almost complete protection even if administered 6h after APAP and a partial protection when given at 15 h. CONCLUSION: These data highlight important mechanistic events in APAP toxicity in PHH and indicate a critical role of JNK in the progression of injury after APAP in humans. The JNK pathway may represent a therapeutic target in the clinic.

Combined transmesenteric and transhepatic recanalization of chronic portal and mesenteric vein occlusion to treat bleeding duodenal varices.

Two patients presented with bleeding duodenal varices secondary to mesenteric and portal vein chronic occlusion. After a failed transhepatic recanalization, a combined transmesenteric and transhepatic approach was used to recanalize the chronic portal and mesenteric venous obstruction. The occluded segment was treated with transmesenteric stent placement in one patient and stent placement and coil embolization of varices in the second patient. Follow-up imaging and endoscopy showed decompression of the duodenal varices in both patients and absence of further bleeding episodes.

Novel immunosuppressive strategies for composite tissue allografts.

PURPOSE OF REVIEW: Vascularized composite tissue allografts (CTAs) provide excellent restorative options for patients with limb loss and other deformities. Acute rejection remains common with CTA and immunosuppression is used in an attempt to prevent rejection. This has created ethical debates regarding the use of intensive immunosuppression for a nonlife-saving procedure. This highlights the need for newer immunosuppressive strategies for CTA, which are described in this review. RECENT FINDINGS: Recent studies have looked into immunomodulation and tolerance to decrease toxicity of immunosuppression. Both strategies have had some success but have their own limitations. Although immunomodulation and decrease in immunosuppression decreases toxicity, it has been associated with higher rates of rejection. Induction of tolerance has achieved some initial success, but the initial conditioning regimens are associated with significant morbidity. SUMMARY: Although recent advancements have been made in the immunosuppressive strategies in CTA, the ideal immunosuppression strategy with low toxicity and infection risk but with the ability to prevent acute and chronic rejection is yet to be discovered.

Liver Transplant Costs and Activity After United Network for Organ Sharing Allocation Policy Changes.

Importance: A new liver allocation policy was implemented by United Network for Organ Sharing (UNOS) in February 2020 with the stated intent of improving access to liver transplant (LT). There are growing concerns nationally regarding the implications this new system may have on LT costs, as well as access to a chance for LT, which have not been captured at a multicenter level. Objective: To characterize LT volume and cost changes across the US and within specific center groups and demographics after the policy implementation. Design, Setting, and Participants: This cross-sectional study collected and reviewed LT volume from multiple centers across the US and cost data with attention to 8 specific center demographics. Two separate 12-month eras were compared, before and after the new UNOS allocation policy: March 4, 2019, to March 4, 2020, and March 5, 2020, to March 5, 2021. Data analysis was performed from May to December 2022. Main Outcomes and Measures: Center volume, changes in cost. Results: A total of 22 of 68 centers responded comparing 1948 LTs before the policy change and 1837 LTs postpolicy, resulting in a 6% volume decrease. Transplants using local donations after brain death decreased 54% (P < .001) while imported donations after brain death increased 133% (P = .003). Imported fly-outs and dry runs increased 163% (median, 19; range, 1-75, vs 50, range, 2-91; P = .009) and 33% (median, 3; range, 0-16, vs 7, range, 0-24; P = .02). Overall hospital costs increased 10.9% to a total of $46 360 176 (P = .94) for participating centers. There was a 77% fly-out cost increase postpolicy ($10 600 234; P = .03). On subanalysis, centers with decreased LT volume postpolicy observed higher overall hospital costs ($41 720 365; P = .048), and specifically, a 122% cost increase for liver imports ($6 508 480; P = .002). Transplant centers from low-income states showed a significant increase in hospital (12%) and import (94%) costs. Centers serving populations with larger proportions of racial and ethnic minority candidates and specifically Black candidates significantly increased costs by more than 90% for imported livers, fly-outs, and dry runs despite lower LT volume. Similarly, costs increased significantly (>100%) for fly-outs and dry runs in centers from worse-performing health systems. Conclusions and Relevance: Based on this large multicenter effort and contrary to current assumptions, the new liver distribution system appears to place a disproportionate burden on populations of the current LT community who already experience disparities in health care. The continuous allocation policies being promoted by UNOS could make the situation even worse.

Development, management, and resolution of biliary complications after living and deceased donor liver transplantation: a report from the adult-to-adult living donor liver transplantation cohort study consortium.

Adult recipients of living donor liver transplantation (LDLT) have a higher incidence of biliary complications than recipients of deceased donor liver transplantation (DDLT). Our objective was to define the intensity of the interventions and the time to resolution after the diagnosis of biliary complications after liver transplantation. We analyzed the management and resolution of posttransplant biliary complications and investigated the comparative effectiveness of interventions in LDLT and DDLT recipients. For the analysis of biliary complications (leaks or strictures), we used a retrospective cohort of patients who underwent liver transplantation at 8 centers between 1998 and 2006 (median follow-up from onset=4.7 years). The numbers, procedure types, and times to resolution were compared for LDLT and DDLT recipients. Posttransplant biliary complications occurred in 47 of the 189 DDLT recipients (25%) and in 141 of the 356 LDLT recipients (40%). Biliary leaks constituted 38% of the post-DDLT biliary complications (n=18) and 65% of the post-LDLT biliary complications (n=91). The median times to first biliary complications were similar for DDLT and LDLT (11 versus 14 days for leaks, P=0.63; 69 versus 107 days for strictures, P=0.34). Overall, 1225 diagnostic and therapeutic procedures, including reoperation and retransplantation, were performed (6.5±5.4 per recipient; 5.5±3.6 for DDLT versus 6.8±5.8 for LDLT, P=0.52). The median number of months to the resolution of a biliary complication (i.e., a tube-, stent-, and drain-free status) did not significantly differ between the DDLT and LDLT groups for leaks (2.3 versus 1.3 months, P=0.29) or strictures (4.9 versus 2.3 months, P=0.61). Although the incidence of biliary complications is higher after LDLT versus DDLT, the treatment requirements and the time to resolution after the development of a biliary complication are similar for LDLT and DDLT recipients.

Transjugular intrahepatic portosystemic shunts in liver transplant recipients: technical analysis and clinical outcome.

OBJECTIVE: The purpose of this study is to compare the technical success of transjugular intrahepatic portosystemic shunt (TIPS) in transplanted versus nontransplanted livers and to assess the clinical outcome of TIPS in liver transplant recipients. MATERIALS AND METHODS: A retrospective audit of patients receiving a TIPS was performed in two institutions during 1996-2009. The technical success of the TIPS was compared for transplanted versus nontransplanted livers. Clinical success was defined as graft survival longer than 1 month with improvement in symptoms. The cohort was divided into grafts that survived less than 3 months versus 3 months or more. The model for end-stage liver disease (MELD) scores and portosystemic gradients before and after TIPS creation were evaluated for predictive value for graft survival. The TIPS stent type, MELD scores and portosystemic gradients before and after TIPS creation, and causes of liver disease were evaluated for their predictive value for ascites response after TIPS creation. RESULTS: Thirty-nine TIPS in transplanted livers were found, representing 5.5% (39/715) of all TIPS procedures performed and 2.0% (39/1992) of all liver transplant recipients. Ninety percent of TIPS in transplanted livers had ascites. The median time from transplant to creation of the TIPS was 29 months (2-127 months). The median MELD score was 16 before and 22 after the TIPS procedure. The technical success rates for TIPS were 97% (38/39) in transplanted livers versus 97% (657/676) in nontransplanted livers (p = 1.00). Intent-to-treat clinical success rates were 36% for all indications versus 31% for ascites only. There were no predictors for ascites response. Six-, 12-, and 24-month graft survival rates were 43%, 32%, and 22%, respectively. One-year graft survival for a MELD score less than 17 versus a score of 17 or higher was 54% versus 8%, respectively (p < 0.05). CONCLUSION: Transplantation does not pose a technical challenge to TIPS creation. One third of patients have a favorable outcome. MELD score is the only predictor of graft survival.

Self expandable metal stents for anastomotic stricture following liver transplant.

BACKGROUND: Endoscopic treatment for biliary strictures with plastic stent placement has been used widely. The use of covered self-expandable metal stents (CSEMS) has been reported in anastomotic strictures post liver transplant. The aim of this study was to evaluate the efficacy of different CSEMS in these subjects. METHODS: A total of 55 patients with anastomotic stricture received CSEMS, which were removed after 3-4 months. There were 19 patients in group A (partially covered SEMS), 21 patients in group B (fully covered SEMS with fins) and 15 patients in group C (fully covered SEMS with flared ends). Technical success, stricture resolution, follows up, and complications were documented. RESULTS: CSEMS were successfully deployed in all 55 cases. There was no evidence of significant difference with regards to stricture resolution (14 [74%] vs. 15 [71%] vs. 9 [60%] p=0.6630, df=2) or complications between groups. Stent-related complications were as follows: three in group A (2 migration, 1 occlusion), five in group B (4 occlusions, 1 migration), and one proximal migration in group C (p=0.3894, df=2). Three cases required surgery (hepatico-jejunostomy) due to refractory strictures. CONCLUSIONS: The observed clinical success rate of CSEMS (70.4%) proved to be below the reported one for multiple plastic stents, while no significant differences between CSEMS types were observed.

Impact of stem cell marker expression on recurrence of TACE-treated hepatocellular carcinoma post liver transplantation.

BACKGROUND: Liver transplantation is the most effective therapy for cirrhosis-associated hepatocellular carcinoma (HCC) but its utility is limited by post-transplant tumor recurrence. Use of the Milan, size-based criteria, has reduced recurrence rate to less than 10% but many patients remain ineligible. Reduction of tumor size with local therapies has been used to "downstage" patients to allow them to qualify for transplantation, but the optimal criteria to predict tumor recurrence in these latter patients has not been established. The existence of a progenitor cell population, sometimes called cancer stem cells (CSCs), has been proposed to be one mechanism accounting for the chemotherapy resistance and recurrence of hepatocellular carcinoma. The aim of this study was to determine if transcatheter arterial chemoemolization (TACE) treated tumors have increased CSC marker expression and whether these markers could be used to predict tumor recurrence. METHODS: Formalin fixed specimens were obtained from 39 HCC liver explants (23 with no treatment and 16 after TACE). Immunohistochemical staining was performed for EpCAM, CD44, CD90, and CD133. Staining for each marker was scored 0-3 by evaluating the number and intensity of positive tumor cells in 5 hpf of tumor in each specimen. RESULTS: TACE treated tumors displayed greater necrosis and fibrosis than non-TACE treated samples but there were no differences in morphology between the viable tumor cells of both groups. In TACE treated specimens, the staining of both EpCAM and CD133 was greater than in non-TACE specimens but CD44 and CD90 were the same. In the TACE group, the presence of high EpCAM staining was associated with tumor recurrence. Four of ten EpCAM high patients recurred while 0 of 6 EpCAM low patients recurred (P = 0.040). None of the other markers predicted recurrence. CONCLUSION: High pre-transplant EpCAM staining predicted HCC recurrence. This suggests that the abundance of tumor cells with a CSC phenotype may be a critical factor in the likelihood of tumor recurrence in patients receiving liver transplantation after TACE.

Elderly recipients of hepatitis C positive renal allografts can quickly develop liver disease.

Our institution explored using allografts from donors with Hepatitis C virus (HCV) for elderly renal transplantation (RT). Thirteen HCV- elderly recipients were transplanted with HCV+ allografts (eD+/R-) between January 2003 and April 2009. Ninety HCV- elderly recipients of HCV- allografts (eD-/R-), eight HCV+ recipients of HCV+ allografts (D+/R+) and thirteen HCV+ recipients of HCV- allografts (D-/R+) were also transplanted. Median follow-up was 1.5 (range 0.8-5) years. Seven eD+/R- developed a positive HCV viral load and six had elevated liver transaminases with evidence of hepatitis on biopsy. Overall, eD+/R- survival was 46% while the eD-/R- survival was 85% (P = 0.003). Seven eD+/R- died during follow-up. Causes included multi-organ failure and sepsis (n = 4), cancer (n = 1), failure-to-thrive (n = 1) and surgical complications (n = 1). One eD+/R- died from causes directly related to HCV infection. In conclusion, multiple eD+/R- quickly developed HCV-related liver disease and infections were a frequent cause of morbidity and mortality.

Prevalence, presentation, and endovascular management of hemodynamically or clinically significant arterio-portal fistulae in living and cadaveric donor liver transplant recipients.

PURPOSE: To compare the prevalence (cadaveric vs. living donor transplants), clinical features, and the effectiveness of endovascular management of significant arterio-portal fistulae (APF) in liver transplant recipients. METHODS: A retrospective audit of liver transplant recipients in two institutions was performed (1996-2009). Significant APF were included and were defined as symptomatic and/or hemodynamically significant (causing graft dysfunction and/or having abnormal Doppler findings in the portal vein). Patients with significant APF were evaluated for presenting symptoms, imaging features, size/branch order portal vein involvement, and effectiveness of the endovascular management (coil embolization). RESULTS: Four significant APF were found in 1992 (0.2%) liver transplants. Two were symptomatic and two were asymptomatic but were hemodynamically significant with liver function test abnormalities. All four APF were found in cadaveric donor graft recipients (0.23%, N = 4/1753) and none in 239 living donor graft recipients. However, there was no statistical difference between cadaveric and living donor graft recipients (p = 1.0, odds ratio = 1.23). Coil embolization was technically and clinically successful in all 4 without complications and causing normalization of the abnormal Doppler findings. CONCLUSION: Significant APF are a rare diagnosis (0.2% of transplants). Coil embolization is a safe and effective treatment option for APF in transplants.

Metabolic Impact of MKP-2 Upregulation in Obesity Promotes Insulin Resistance and Fatty Liver Disease.

The mechanisms connecting obesity with type 2 diabetes, insulin resistance, nonalcoholic fatty liver disease, and cardiovascular diseases remain incompletely understood. The function of MAPK phosphatase-2 (MKP-2), a type 1 dual-specific phosphatase (DUSP) in whole-body metabolism, and how this contributes to the development of diet-induced obesity, type 2 diabetes (T2D), and insulin resistance is largely unknown. We investigated the physiological contribution of MKP-2 in whole-body metabolism and whether MKP-2 is altered in obesity and human fatty liver disease using MKP-2 knockout mice models and human liver tissue derived from fatty liver disease patients. We demonstrate that, for the first time, MKP-2 expression was upregulated in liver tissue in humans with obesity and fatty liver disease and in insulin-responsive tissues in mice with obesity. MKP-2-deficient mice have enhanced p38 MAPK, JNK, and ERK activities in insulin-responsive tissues compared with wild-type mice. MKP-2 deficiency in mice protects against diet-induced obesity and hepatic steatosis and was accompanied by improved glucose homeostasis and insulin sensitivity. Mkp-2-/- mice are resistant to diet-induced obesity owing to reduced food intake and associated lower respiratory exchange ratio. This was associated with enhanced circulating insulin-like growth factor-1 (IGF-1) and stromal cell-derived factor 1 (SDF-1) levels in Mkp-2-/- mice. PTEN, a negative regulator of Akt, was downregulated in livers of Mkp-2-/- mice, resulting in enhanced Akt activity consistent with increased insulin sensitivity. These studies identify a novel role for MKP-2 in the regulation of systemic metabolism and pathophysiology of obesity-induced insulin resistance and fatty liver disease.

Liver allografts from hepatitis C positive donors can offer good outcomes in hepatitis C positive recipients: a US National Transplant Registry analysis.

Organ donors are screened for the hepatitis C antibody (anti-HCV) and those with positive tests can be used under extended criteria donation. However, there is still a question of long-term organ viability. The aim of this study was to assess the long-term outcomes of anti-HCV positive (HCV+) liver grafts. The US Organ Procurement and Transplantation Network Scientific Registry was reviewed for the period from April 1994 to February 6, 2008 and 56,275 liver transplantations were analyzed. In total, there were 19,496 HCV+ recipients and 934 HCV+ donors. Patient and graft survival were assessed accounting for both donor and recipient anti-HCV status. Multivariable proportional hazards survival models were developed to adjust for factors known to affect post-transplant survival. With anti-HCV negative (HCV-) recipient/HCV- donor as the reference, the adjusted hazard ratio for death was similar for HCV+ recipient/HCV- donor compared with HCV+ recipient/HCV+ donor (1.176 vs. 1.165, P = 0.91). Our results suggest that HCV+ liver donors do not subject the HCV+ recipient to an increased risk for death over the HCV- donor, keeping in mind that careful donor and recipient selection is critical for the proper use of these extended criteria donors.

Liver transplantation for T3 lesions has higher waiting list mortality but similar survival compared to T1 and T2 lesions.

BACKGROUND: Restrictive staging criteria for liver transplant (LT) patients with HCC in the U.S. have resulted in favorable long-term recurrence-free survival, but these criteria exclude a subgroup of patients who, despite tumor size beyond T2 stage, demonstrate an acceptable outcome. The aim of this study was to assess the waiting list and post-transplant mortality of patients with HCC tumors greater than Milan T2 stage. METHODS: The U.S. OPTN standard transplant dataset was analyzed for patients with a diagnosis of HCC who were listed for liver transplantation between February 2002 and 2008. Those patients with Milan T3 stage tumors were compared to patients with T1 and T2 lesions. Multivariate survival models were developed to investigate independent predictors of death or tumor recurrence post-transplant. RESULTS: 7,391 patients with HCC were identified. 351 (4.75%) had T3 lesions. Compared to non-T3 patients, total tumor burden was greater and total alpha-fetoprotein (AFP) was higher in the T3 patients. T3 patients also were more likely to receive pretransplant locoregional therapy. There were no significant differences between T3 patients and non-T3 patients in demographic variables or physiologic MELD score at the time of transplant, waiting time, or donor risk index. Waiting list mortality was increased for T3 patients compared to non-T3 and tumor progression while waiting was higher. Independent predictors of waiting list mortality included physiologic MELD score at the time of listing, total tumor burden, and serum AFP. There was significant regional variation in the utilization of exceptions for T3 patients and UNOS regions 4, 9, and 10 performed a higher percentage of their transplants in T3 patients compared to other regions. There was no difference in post transplant survival between T3 and non-T3 patients. Independent predictors of post-transplant mortality included physiologic MELD score at the time of transplant, recipient age, and donor risk index. In patients with T3 tumors, total tumor burden was not an independent predictor of post transplant survival. CONCLUSIONS: Patients who are listed for liver transplantation with Milan stage T3 HCC have higher waiting list mortality but have similar post-transplant survival compared to patients with T1 and T2 HCC.