Signaling through the interleukin-4 and interleukin-13 receptor complexes regulates cholangiocyte TMEM16A expression and biliary secretion.

TMEM16A is a Ca2+-activated Cl- channel in the apical membrane of biliary epithelial cells, known as cholangiocytes, which contributes importantly to ductular bile formation. Whereas cholangiocyte TMEM16A activity is regulated by extracellular ATP-binding membrane purinergic receptors, channel expression is regulated by interleukin-4 (IL-4) through an unknown mechanism. Therefore, the aim of the present study was to identify the signaling pathways involved in TMEM16A expression and cholangiocyte secretion. Studies were performed in polarized normal rat cholangiocyte monolayers, human Mz-Cha-1 biliary cells, and cholangiocytes isolated from murine liver tissue. The results demonstrate that all the biliary models expressed the IL-4Rα/IL-13Rα1 receptor complex. Incubation of cholangiocytes with either IL-13 or IL-4 increased the expression of TMEM16A protein, which was associated with an increase in the magnitude of Ca2+-activated Cl- currents in response to ATP in single cells and the short-circuit current response in polarized monolayers. The IL-4- and IL-13-mediated increase in TMEM16A expression was also associated with an increase in STAT6 phosphorylation. Specific inhibition of JAK-3 inhibited the increase in TMEM16A expression and the IL-4-mediated increase in ATP-stimulated currents, whereas inhibition of STAT6 inhibited both IL-4- and IL-13-mediated increases in TMEM16A expression and ATP-stimulated secretion. These studies demonstrate that the cytokines IL-13 and IL-4 regulate the expression and function of biliary TMEM16A channels through a signaling pathway involving STAT6. Identification of this regulatory pathway provides new insight into biliary secretion and suggests new targets to enhance bile formation in the treatment of cholestatic liver disorders.NEW & NOTEWORTHY The Ca2+-activated Cl- channel transmembrane member 16A (TMEM16A) has emerged as an important regulator of biliary secretion and hence, ductular bile formation. The present studies represent the initial description of the regulation of TMEM16A expression in biliary epithelium. Identification of this regulatory pathway involving the IL-4 and IL-13 receptor complex and JAK-3 and STAT-6 signaling provides new insight into biliary secretion and suggests new therapeutic targets to enhance bile formation in the treatment of cholestatic liver disorders.

The Synthetic Triterpenoid RTA 405 (CDDO-EA) Halts Progression of Liver Fibrosis and Reduces Hepatocellular Carcinoma Size Resulting in Increased Survival in an Experimental Model of Chronic Liver Injury.

UNLABELLED: Patients with cirrhosis have an increased risk of developing liver cancer and a higher rate of mortality. Cirrhosis currently has no known cure, and patients may benefit from new agents aimed at alleviating their complications and slowing down the rate of disease progression. Therefore, the effects of the orally bioavailable synthetic triterpenoid 2-cyano-3,12-dioxooleana- 1,9(11)-dien-28-oate-ethyl amide (CDDO-EA, RTA 405), which has potent antioxidative and antiinflammatory properties, was evaluated in a chronic carbon tetrachloride (CCl(4))-induced model of liver cirrhosis and hepatocellular carcinoma (HCC). Mice were injected with CCl(4) (to induce fibrosis and cirrhosis) or placebo biweekly for 12 weeks followed by CDDO-EA in the diet for 18 weeks with continued biweekly injections of CCl(4). Chronic CCl(4) administration resulted in cirrhosis, ascites, and HCC formation, associated with increased serum transforming growth factor-ß1, hepatic hydroxyproline content, and increased serum bilirubin. CDDO-EA, whose administration commenced after establishment of liver fibrosis, decreased liver fibrosis progression, serum bilirubin, ascites, and HCC formation and markedly increased overall survival. CDDO-EA also attenuated -TNFα (tumor necrosis factor-α), α-SMA (alpha smooth muscle actin), augmented -IL-10 levels, and improved histologic and serologic markers of fibrosis. CONCLUSIONS: CDDO-EA mitigates the progression of liver fibrosis induced by chronic CCl(4) administration, which is associated with the induction of antifibrogenic genes and suppression of profibrogenic genes.

Changes in Morbidity and Abortion Care in Ethiopia After Legal Reform: National Results from 2008 and 2014.

CONTEXT: In Ethiopia, liberalization of the abortion law in 2005 led to changes in abortion services. It is important to examine how levels and types of abortion care-i.e., legal abortion and treatment of abortion complications-changed over time. METHODS: Between December 2013 and May 2014, data were collected on symptoms, procedures and treatment from 5,604 women who sought abortion care at a sample of 439 public and private health facilities; the sample did not include lower-level private facilities-some of which provide abortion care-to maintain comparability with the sample from a 2008 study. These data were combined with monitoring data from 105,806 women treated in 74 nongovernmental organization facilities in 2013. Descriptive analyses were conducted and annual estimates were calculated to compare the numbers and types of abortion care services provided in 2008 and 2014. RESULTS: The estimated annual number of women seeking a legal abortion in the types of facilities sampled increased from 158,000 in 2008 to 220,000 in 2014, and the estimated number presenting for postabortion care increased from 58,000 to 125,000. The proportion of abortion care provided in the public sector increased from 36% to 56% nationally. The proportion of women presenting for postabortion care who had severe complications rose from 7% to 11%, the share of all abortion procedures accounted for by medical abortion increased from 0% to 36%, and the proportion of abortion care provided by midlevel health workers increased from 48% to 83%. Most women received postabortion contraception. CONCLUSIONS: Ethiopia has made substantial progress in expanding comprehensive abortion care; however, eradication of morbidity from unsafe abortion has not yet been achieved.

The Estimated Incidence of Induced Abortion in Ethiopia, 2014: Changes in the Provision of Services Since 2008.

CONTEXT: In 2005, Ethiopia's parliament amended the penal code to expand the circumstances in which abortion is legal. Although the country has expanded access to abortion and postabortion care, the last estimates of abortion incidence date from 2008. METHODS: Data were collected in 2014 from a nationally representative sample of 822 facilities that provide abortion or postabortion care, and from 82 key informants knowledgeable about abortion services in Ethiopia. The Abortion Incidence Complications Methodology and the Prospective Morbidity Methodology were used to estimate the incidence of abortion in Ethiopia and assess trends since 2008. RESULTS: An estimated 620,300 induced abortions were performed in Ethiopia in 2014. The annual abortion rate was 28 per 1,000 women aged 15-49, an increase from 22 per 1,000 in 2008, and was highest in urban regions (Addis Ababa, Dire Dawa and Harari). Between 2008 and 2014, the proportion of abortions occurring in facilities rose from 27% to 53%, and the number of such abortions increased substantially; nonetheless, an estimated 294,100 abortions occurred outside of health facilities in 2014. The number of women receiving treatment for complications from induced abortion nearly doubled between 2008 and 2014, from 52,600 to 103,600. Thirty-eight percent of pregnancies were unintended in 2014, a slight decline from 42% in 2008. CONCLUSIONS: Although the increases in the number of women obtaining legal abortions and postabortion care are consistent with improvements in women's access to health care, a substantial number of abortions continue to occur outside of health facilities, a reality that must be addressed.

The role of intrahepatic CD3+/CD4-/CD8- double negative T (DN T) cells in enhanced acetaminophen toxicity.

UNLABELLED: The role of the immune system, specifically NK, NKT and CD3 cells, in acetaminophen (APAP) induced liver injury remains inconsistently defined. In the present study, wild type (C57BL/6J) mice and granzyme B deficient (GrB -/-) mice were treated with acetaminophen to assess the role of the immune system in acute liver injury. Doses of acetaminophen that induced sub lethal liver injury in wild type mice unexpectedly produced fatal hepatotoxicity in granzyme B deficient (GrB -/-) mice. Analysis revealed that GrB -/- mice had an increased population of intrahepatic CD3 (+), CD4 (-), and CD8 (-) lymphocytes expressing the CD69 activation marker and Fas ligand. Depletion of these cells in the GrB -/- and wild type mice made them less susceptible to APAP injury, while depletion of NK1.1 (+) cells or both CD4 (+) and CD8 (+) T cells failed to provide the same hepatoprotection. Transfer of the GrB -/- IHLs further exacerbated liver injury and increased mortality in wild type mice but not in LRP/LPR mice, lacking fas expression. CONCLUSIONS: Acetaminophen toxicity is enhanced by the presence of activated, FasL expressing intrahepatic CD3 (+), CD4 (-), CD8 (-), NK1.1 (-) T cells. Depletion of these cells from GrB -/- mice and wild type mice greatly reduces mortality and improves the course of liver injury recovery.

Predictors of liver transplant eligibility for patients with hepatocellular carcinoma in a safety net hospital.

BACKGROUND: Liver transplantation for patients with hepatocellular carcinoma (HCC) affords excellent long-term survival but is limited to patients with early stage tumors. Predictors for orthotopic liver transplantation eligibility are not well defined for patients in a safety-net hospital system. AIMS: To clarify the clinical presentation of HCC and define predictors for early stage disease in a racially diverse safety-net hospital system. METHODS: We retrospectively reviewed records of patients with HCC presenting to a large urban county hospital between January 1998 and October 2007. Logistic regression analysis was used to find predictors of OLT eligibility. RESULTS: Of the 266 patients with HCC, 62% had multiple tumors, 47% had portal vein thrombosis and only 22% were potential liver transplant candidates based on Milan criteria. Male gender (OR 0.33; 95% CI 0.17-0.65) and AFP levels > 20 ng/mL (OR 0.22; 95% CI 0.11-0.45) were negative predictors of liver transplant eligibility. Age, race, and underlying viral liver disease were not significant predictors of early tumor stage. CONCLUSIONS: A minority of HCC patients in a safety-net hospital are eligible for liver transplant at the time of diagnosis. Men have more advanced tumors at presentation, which may be related to more aggressive tumor biology or differential rates of HCC surveillance.

Susceptibility to acetaminophen (APAP) toxicity unexpectedly is decreased during acute viral hepatitis in mice.

Acetaminophen (APAP) hepatotoxicity results from cytochrome P450 metabolism of APAP to the toxic metabolite, n-acetyl-benzoquinone imine (NAPQI), which reacts with cysteinyl residues to form APAP adducts and initiates cell injury. As APAP is commonly used during viral illnesses there has been concern that APAP injury may be additive to that of viral hepatitis, leading physicians to advise against its use in such patients; this has not been investigated experimentally. We infected C57BL/6 male mice with replication-deficient adenovirus to produce moderately severe acute viral hepatitis and observed that APAP doses that were hepatotoxic or lethal in control mice produced neither death nor additional increase in serum ALT when administered to infected mice at the peak of virus-induced liver injury. Moreover, the concentration of hepatic APAP-protein adducts formed in these mice was only 10% that in control mice. Protection from APAP hepatotoxicity also was observed earlier in the course of infection, prior to the peak virus-induced ALT rise. Hepatic glutathione limits APAP-protein adduct formation but glutathione levels were similar in control and infected mice. Cyp1a2 (E.C. 1.14.14.1) and Cyp2e1 (E.C. 1.14.13.n7) mRNA expression decreased by 3 days post-infection and hepatic Cyp2e1 protein levels were reduced almost 90% at 7 days, when adduct formation was maximally inhibited. In vitro, hepatocytes from virally infected mice also were resistant to APAP-induced injury but sensitive to NAPQI. Rather than potentiating APAP-induced liver injury, acute viral hepatitis in this model resulted in selective down-regulation of APAP metabolizing P450s in liver and decreased the risk of APAP hepatotoxicity.

Granzyme C supports efficient CTL-mediated killing late in primary alloimmune responses.

It is well established that granzymes A and B play a role in CTL killing of target cells by the perforin-dependent granule exocytosis pathway. The functions of multiple additional granzymes expressed in CTL are less well defined. In the present studies, CTL generated from mice deficient in dipeptidyl peptidase 1 (DPP1) were used to investigate the contribution of granzyme C to CTL killing of allogeneic target cells. DPP1 is required for activation of granzymes A and B by proteolytic removal of their N-terminal dipeptide prodomains while a significant portion of granzyme C is processed normally in the absence of DPP1. Cytotoxicity of DPP1(-/-) CTL generated in early (5-day) MLC in vitro and in peritoneal exudate cells 5 days after initial allogeneic sensitization in vivo was significantly impaired compared with wild-type CTL. Following 3 days of restimulation with fresh allogeneic stimulators however, cytotoxicity of these DPP1(-/-) effector cells was comparable to that of wild-type CTL. Killing mediated by DPP1(-/-) CTL following restimulation was rapid, perforin dependent, Fas independent and associated with early mitochondrial injury, phosphatidyl serine externalization, and DNA degradation, implicating a granzyme-dependent apoptotic pathway. The increased cytotoxicity of DPP1(-/-) CTL following restimulation coincided with increased expression of granzyme C. Moreover, small interfering RNA inhibition of granzyme C expression during restimulation significantly decreased cytotoxicity of DPP1(-/-) but not wild-type CTL. These results indicate that during late primary alloimmune responses, granzyme C can support CTL-mediated killing by the granule exocytosis pathway in the absence of functional granzymes A or B.

Prediction of clinical outcomes in primary biliary cirrhosis by serum enhanced liver fibrosis assay.

UNLABELLED: Primary biliary cirrhosis (PBC) is sometimes diagnosed based on a positive antimitochondrial antibody in the appropriate clinical setting without a liver biopsy. Although a liver biopsy can assess the extent of liver fibrosis and provide prognostic information, serum fibrosis markers avoid biopsy complications and sampling error and provide results as a continuous variable, which may be more precise than categorical histological stages. The current study was undertaken to evaluate serum fibrosis markers as predictors of clinical progression in a large cohort of PBC patients. Serial liver biopsy specimens and serum samples were collected every 2 years in 161 PBC subjects for a median of 7.3 years. Clinical progression was defined as development of one or more of the following events: varices, variceal bleed, ascites, encephalopathy, liver transplantation, or liver-related death. Serum hyaluronic acid, tissue inhibitor of metalloproteinase 1, and procollagen III aminopeptide were measured and entered into the previously validated enhanced liver fibrosis (ELF) algorithm. The ability of ELF, histological fibrosis, bilirubin, Model for End-Stage Liver Disease (MELD), and Mayo Risk Score to differentiate between individuals who would experience a clinical event from those who would not was evaluated at different time points. Event-free survival was significantly lower in those with high baseline ELF. Each 1-point increase in ELF was associated with a threefold increase in future complications. The prognostic performance of all tests was similar when performed close to the time of the first event. However, at earlier times in the disease process (4 and 6 years before the first event), the prognostic performance of ELF was significantly better than MELD or Mayo R score. CONCLUSION: The ELF algorithm is a highly accurate noninvasive measure of PBC disease severity that provides useful long-term prognostic information.

Intrahepatic lymphocyte expression of dipeptidyl peptidase I-processed granzyme B and perforin induces hepatocyte expression of serine proteinase inhibitor 6 (Serpinb9/SPI-6).

Human proteinase inhibitor 9 (PI-9/serpinB9) and the murine ortholog, serine proteinase inhibitor 6 (SPI-6/serpinb9) are members of a family of intracellular serine proteinase inhibitors (serpins). PI-9 and SPI-6 expression in immune-privileged cells, APCs, and CTLs protects these cells against the actions of granzyme B, and when expressed in tumor cells or virally infected hepatocytes, confers resistance to killing by CTL and NK cells. The present studies were designed to assess the existence of any correlation between granzyme B activity in intrahepatic lymphocytes and induction of hepatic SPI-6 expression. To this end, SPI-6, PI-9, and serpinB9 homolog expression was examined in response to IFN-alpha treatment and during in vivo adenoviral infection of the liver. SPI-6 mRNA expression increased 10- to 100-fold in the liver after IFN-alpha stimulation and during the course of viral infection, whereas no significant up-regulation of SPI-8 and <5-fold increases in other PI-9/serpinB9 homolog mRNAs was observed. Increased SPI-6 gene expression during viral infection correlated with influxes of NK cells and CTL. Moreover, IFN-alpha-induced up-regulation of hepatocyte SPI-6 mRNA expression was not observed in NK cell-depleted mice. Additional experiments using genetically altered mice either deficient in perforin or unable to process or express granzyme B indicated that SPI-6 is selectively up-regulated in hepatocytes in response to infiltration of the liver by NK cells that express perforin and enzymatically active granzyme B.

The role of serpinb9/serine protease inhibitor 6 in preventing granzyme B-dependent hepatotoxicity.

UNLABELLED: Virally infected hepatocytes are resistant to cytotoxic lymphocyte killing by perforin-dependent and granzyme-dependent effector mechanisms. The present studies were designed to examine the role of serine protease inhibitor 6 (SPI-6) in limiting granzyme B-dependent cytotoxic effector mechanisms in the liver. SPI-6-specific small interfering RNA (siRNA) administration to C57Bl/6J (B6) mice elicited transient alanine aminotransferase (ALT) elevations that were not observed in either granzyme B-deficient B6 (B6.gzmb(-/-)) or natural killer (NK) cell-depleted B6 mice. When SPI-6 expression was abolished by siRNA administration at the time of infection with a recombinant, replication-deficient adenovirus [E1-deleted adenovirus encoding beta-galactosidase (AdCMV-LacZ)], earlier and dramatically increased, and earlier ALT elevations were observed in wild-type B6 but not in B6.gzmb(-/-) or NK cell-depleted mice. When a 3-fold higher dose of AdCMV-LacZ was administered to B6 mice, the coadministration of SPI-6 siRNA resulted in the early onset of lethal, acute liver failure. Of note, the accelerated clearance of AdCMV-LacZ was observed in recipients of SPI-6 siRNA. CONCLUSION: These results indicate that the regulated expression of SPI-6 in hepatocytes during viral infection or following noninfectious causes of liver injury protects hepatocytes against excessively vigorous granzyme B-dependent killing but may also delay immune clearance of virally infected hepatocytes.

Sertraline as a first-line treatment for cholestatic pruritus.

UNLABELLED: Pruritus is frequently the most debilitating symptom of cholestatic liver diseases. Moreover, existing therapies are often ineffective. Recent small, retrospective case series reports suggest that serotonin reuptake inhibitors can improve pruritus. This study was undertaken to establish the dose of sertraline and to evaluate its efficacy for cholestatic pruritus. Twenty one subjects with chronic pruritus due to liver disease (including primary biliary cirrhosis, primary sclerosing cholangitis, chronic hepatitis C, and postnecrotic cirrhosis) initially underwent an open-label, dose escalation to determine the dose with optimal efficacy and tolerability. After a washout period, 12 of the subjects entered a randomized, double-blind, placebo-controlled trial. Participants quantified their pruritus using a 0-10 visual analog scale, and pruritus was assessed for distribution, timing, degree of disability, and physical evidence of scratching. The optimum sertraline dose (75-100 mg/day) was well tolerated. In the controlled portion of the study, itch scores improved in patients taking sertraline, but worsened in patients taking placebo (P=0.009). Changes in itch distribution, duration, direction, and physical evidence of scratching paralleled changes in the visual analog pruritus score. CONCLUSION: Sertraline seems to be an effective, well-tolerated treatment for pruritus due to chronic liver disease. These results suggest that serotonergic pathways are important in the perception of itch.