Investigating potential confounding by indication when considering the association between proton pump inhibitor use, infection, hepatic encephalopathy and mortality in hospitalised decompensated cirrhosis: a post-hoc analysis of the ATTIRE trial.

Background: Proton pump inhibitors (PPIs) are commonly prescribed to prevent and treat upper gastrointestinal ulceration and bleeding. Studies have identified increased incidence of spontaneous bacterial peritonitis and hepatic encephalopathy (HE) in cirrhosis patients taking PPIs. However, results are conflicting, and as PPIs are prescribed for variceal bleeding, a major risk factor for infection and HE, it is challenging to discern whether these associations are causal. Methods: In this post-hoc analysis of the ATTIRE trial, we pooled all patient data to investigate the effects of PPI use on clinical outcomes. ATTIRE was a multicentre, open-label, randomised trial of targeted 20% human albumin solution (HAS) daily infusions versus standard care involving 777 adults with decompensated cirrhosis hospitalised with acute complications and albumin <30 g/L. Study recruitment was between Jan 25, 2016, and June 28, 2019, at 35 hospitals across England, Scotland, and Wales. Key exclusion criteria were advanced hepatocellular carcinoma with life expectancy <8 weeks and patients receiving palliative care. In ATTIRE, patients were grouped by PPI use at trial entry. We studied infection and HE at baseline and incidence of hospital acquired infection, new onset HE, renal dysfunction and mortality. We attempted with propensity score matching to account for differences in disease severity. Findings: Overall PPI use at baseline was not associated with increased incidence of infection, renal dysfunction or mortality, but was associated with significantly increased incidence of grade III/IV HE during hospital stay (P = 0.011). This was only significant for those taking intravenous PPIs and these patients had >10 times the incidence of variceal bleeding and near double the 28-day mortality compared to non-PPI patients. However, propensity score matching was not possible as there was such a strong selection of patients for PPI use, that we could not find sufficient non-PPI patients to match to. We found no impact of PPI use on plasma markers of bacterial translocation, infection or systemic inflammation. Interpretations: Our real-world data from a completed randomised trial show that PPIs are widely prescribed in the UK and judicious use appears safe in patients hospitalised with decompensated cirrhosis. However, patients prescribed PPIs had fundamentally different phenotypes to those not prescribed PPIs, a form of confounding by indication, which should be strongly considered when interpreting studies and making recommendations about their use. Funding: Wellcome Trust and Department of Health and Social Care.

An update on the management of cholestatic liver diseases.

Cholestatic liver diseases are a challenging spectrum of conditions arising from damage to bile ducts, leading to build-up of bile acids and inflammatory processes that cause injury to cholangiocytes and hepatocytes. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the two most common cholestatic disorders. In this review we detail the latest guidelines for the diagnosis and management of patients with these two conditions.

Analysis of Endoscopic Radiofrequency Ablation of Biliary Malignant Strictures in Pancreatic Cancer Suggests Potential Survival Benefit.

BACKGROUND: Pancreatic carcinoma is often inoperable, carries a poor prognosis, and is commonly complicated by malignant biliary obstruction. Phase I/II studies have demonstrated good safety and early stent patency using endoscopic biliary radiofrequency ablation (RFA) as an adjunct to self-expanding metal stent (SEMS) insertion for biliary decompression. AIM: To analyze the clinical efficacy of endobiliary RFA. METHODS: Retrospective case-control analysis was carried out for 23 patients with surgically unresectable pancreatic carcinoma and malignant biliary obstruction undergoing endoscopic RFA and SEMS insertion and 46 controls (SEMS insertion alone) in a single tertiary care center. Controls were stringently matched for age, sex, metastases, ASA/comorbidities. Survival, morbidity, and stent patency rates were assessed. RESULTS: RFA and control groups were closely matched-ASA 2.35 ± 0.65 versus 2.54 ± 0.50, p = 0.086; metastases 9/23 (39.1%) versus 18/46 (39.1%), p = 0.800; chemotherapy 16/23 (69.6%) versus 24/46 (52.2%), p = 0.203. Median survival in RFA group was 226 days (IQR 140-526 days) versus 123.5 days (IQR 44-328 days) in controls (p = 0.010). RFA was independently predictive of survival at 90 days (OR 21.07, 95% CI 1.45-306.64, p = 0.026) and 180 days (OR 4.48, 95% CI 1.04-19.30, p = 0.044) in multivariate analysis. SEMS patency rates were equivalent in both groups. RFA was well tolerated with minimal side effects. CONCLUSIONS: Endoscopic RFA is a safe and efficacious adjunctive treatment in patients with advanced pancreatic malignancy and biliary obstruction and may confer early survival benefit. Randomized prospective clinical trials of this new modality are mandated.

Assessment of bone mineral density in tenofovir-treated patients with chronic hepatitis B: can the fracture risk assessment tool identify those at greatest risk?

BACKGROUND: Tenofovir disoproxil fumarate (TDF) is an established nucleotide analogue in the treatment of chronic hepatitis B. Bone mineral density loss has been described in TDF-treated patients with human immunodeficiency virus infection, but limited data exist for patients with chronic hepatitis B. Dual X-ray absorptiometry (DEXA) was used to determine bone mineral density changes in TDF-exposed patients. We evaluated the accuracy of the Fracture Risk Assessment Tool (FRAX) as an alternative to DEXA in clinical practice. METHODS: A total of 170 patients were studied: 122 were exposed to TDF, and 48 were controls. All patients underwent DEXA, and demographic details were recorded. FRAX scores (before and after DEXA) were calculated. RESULTS: TDF was associated with a lower hip T score (P = .02). On univariate and multivariate analysis, advancing age, smoking, lower body mass index, and TDF exposure were independent predictors of low bone mineral density. In addition, the pre-DEXA FRAX score was an accurate predictor of the post-DEXA FRAX treatment recommendation (100% sensitivity and 83% specificity), area under the curve 0.93 (95% CI, .87-.97, P < .001). CONCLUSIONS: TDF-treated patients with chronic hepatitis B have reduced bone mineral density, but the reduction is limited to 1 anatomical site. Age and advanced liver disease are additional contributing factors, underlining the importance of multifactorial fracture risk assessment. FRAX can accurately identify those at greatest risk of osteoporotic fracture.

Proteinase activated receptor 1 mediated fibrosis in a mouse model of liver injury: a role for bone marrow derived macrophages.

Liver fibrosis results from the co-ordinated actions of myofibroblasts and macrophages, a proportion of which are of bone marrow origin. The functional effect of such bone marrow-derived cells on liver fibrosis is unclear. We examine whether changing bone marrow genotype can down-regulate the liver's fibrotic response to injury and investigate mechanisms involved. Proteinase activated receptor 1 (PAR1) is up-regulated in fibrotic liver disease in humans, and deficiency of PAR1 is associated with reduced liver fibrosis in rodent models. In this study, recipient mice received bone marrow transplantation from PAR1-deficient or wild-type donors prior to carbon tetrachloride-induced liver fibrosis. Bone marrow transplantation alone from PAR1-deficient mice was able to confer significant reductions in hepatic collagen content and activated myofibroblast expansion on wild-type recipients. This effect was associated with a decrease in hepatic scar-associated macrophages and a reduction in macrophage recruitment from the bone marrow. In vitro, PAR1 signalling on bone marrow-derived macrophages directly induced their chemotaxis but did not stimulate proliferation. These data suggest that the bone marrow can modulate the fibrotic response of the liver to recurrent injury. PAR1 signalling can contribute to this response by mechanisms that include the regulation of macrophage recruitment.

Diagnostic and therapeutic utility of single-operator peroral cholangioscopy for indeterminate biliary lesions and bile duct stones.

BACKGROUND AND AIM: We aimed to evaluate the diagnostic utility of single-operator peroral cholangioscopy (SOC) for indeterminate biliary lesions and its usefulness in electrohydraulic lithotripsy (EHL) of biliary stones not amenable to conventional endoscopic therapy. PATIENTS AND METHODS: All patients undergoing SpyGlass SOC in four UK tertiary centres between 2008 and 2010 were retrospectively enrolled. Patients were followed up until death or the last clinic visit until May 2011. The operating characteristics of SOC for detecting malignant lesions and the stone clearance rate after SOC-guided EHL were calculated. RESULTS: A total of 165 patients underwent 179 SOC procedures. Sixty-six percent were referred for indeterminate biliary strictures, 13% for filling defects and 21% for SOC-guided EHL. Cannulation with the SOC system was successful in 95% but visualization was inadequate in 13%. Primary sclerosing cholangitis was a risk factor for failed cannulation and conscious sedation (vs. general anaesthesia) for inadequate visualization (P<0.05). The accuracy of SOC for diagnosing malignant lesions was 87%. SOC-guided biopsies were adequate in 72%. Obtaining at least four versus less than four biopsy specimens resulted more often in adequate samples (90 vs. 64%, P=0.037). Complete stone clearance could be achieved in 73% of patients. The adverse event rate was 9.6%. Cholangitis was the most common event (56%, one fatal). CONCLUSION: SOC is useful for the differential diagnosis of indeterminate biliary lesions and the treatment of 'difficult' biliary stones. The adequacy of SOC-guided biopsies is related to the number of specimens obtained. Primary sclerosing cholangitis is related to failed cannulation with the SOC system, whereas general anaesthesia is related to adequate visualization.

Bone marrow-derived cells contribute to cerulein-induced pancreatic fibrosis in the mouse.

Bone marrow (BM) cells may transdifferentiate into circulating fibrocytes and myofibroblasts in organ fibrosis. In this study, we investigated the contribution and functional roles of BM-derived cells in murine cerulein-induced pancreatic fibrosis. C57/BL6 female mice wild-type (WT) or Col 1α1(r/r) male BM transplant, received supraphysiological doses of cerulein to induce pancreatic fibrosis. The CD45(+)Col 1(+) fibrocytes isolated from peripheral blood (PB) and pancreatic tissue were examined by in situ hybridization for Y chromosome detection. The number of BM-derived myofibroblasts, the degree of Sirius red staining and the levels of Col 1α1 mRNA were quantified. The Y chromosome was detected in the nuclei of PB CD45(+)Col 1(+) fibrocytes, confirming that circulating fibrocytes can be derived from BM. Co-expression of α-smooth muscle actin illustrated that fibrocytes can differentiate into myofibroblasts. The number of BM-derived myofibroblasts, degree of collagen deposition and pro-collagen I mRNA expression were higher in the mice that received Col 1α1(r/r) BM, (cells that produce mutated, collagenase-resistant collagen) compared to WT BM, indicating that the genotype of BM cells can alter the degree of pancreatic fibrosis. Our data indicate that CD45(+)Col 1(+) fibrocytes in the PB can be BM-derived, functionally contributing to cerulein-induced pancreatic fibrosis in mice by differentiating into myofibroblasts.

Remodelling of extracellular matrix is a requirement for the hepatic progenitor cell response.

BACKGROUND AND METHODS: In advanced liver damage, hepatic regeneration can occur through proliferation of a resident hepatic progenitor cell (HPC) population. HPCs are located within a designated niche in close association with myofibroblasts and bone marrow (BM) derived macrophages. Extra-cellular matrix (ECM) laminin invariably surrounds HPCs, but the functional requirement of this matrix-cell association is untested in vivo. Using the collagen Iα1((r/r)) mouse (r/r), which produces mutated collagen I resistant to matrix metalloproteinase degradation and has an exaggerated fibrotic response to liver injury, we test the relationship between collagen degradation, laminin deposition, and the HPC response. RESULTS: Chronic fibrotic carbon tetrachloride (CCl4) injury can induce a florid HPC response associated with dense laminin deposition. In the recovery phase after chronic CCl4 injury, r/r mice have a markedly attenuated HPC response compared to wild-types, together with persistence of collagen I and failure to deposit ECM laminin. Similar results were found in r/r mice given the choline-deficient ethionine supplemented diet, another model of the HPC response. In cross-over sex-mismatched BM transplantation (BMT) experiments between r/r mice and wild-types, the blunted HPC response of r/r mice was not rescued by wild-type BMT and likewise not conferred on to wild-type recipients by r/r BMT, demonstrating that the attenuated HPC response in r/r mice is a property intrinsic to the liver. CONCLUSION: Failure of ECM remodelling after chronic fibrotic liver injury hinders the ability of the liver to activate HPCs. Laminin-progenitor cell interactions within the HPC niche are a critical for HPC mediated regeneration.