Andrew J. Bathgate

Dense fine-mapping study identifies new susceptibility loci for primary biliary cirrhosis

We genotyped 2,861 cases of primary biliary cirrhosis (PBC) from the UK PBC Consortium and 8,514 UK population controls across 196,524 variants within 186 known autoimmune risk loci. We identified 3 loci newly associated with PBC (at P < 5 × 10−8), increasing the number of known susceptibility loci to 25. The most associated variant at 19p12 is a low-frequency nonsynonymous SNP in TYK2, further implicating JAK-STAT and cytokine signaling in disease pathogenesis. An additional five loci contained nonsynonymous variants in high linkage disequilibrium (LD; r2 > 0.8) with the most associated variant at the locus. We found multiple independent common, low-frequency and rare variant association signals at five loci. Of the 26 independent non–human leukocyte antigen (HLA) signals tagged on the Immunochip, 15 have SNPs in B-lymphoblastoid open chromatin regions in high LD (r2 > 0.8) with the most associated variant. This study shows how data from dense fine-mapping arrays coupled with functional genomic data can be used to identify candidate causal variants for functional follow-up.

The effect of polymorphisms in tumor necrosis factor-alpha, interleukin-10, and transforming growth factor-beta1 genes in acute hepatic allograft rejection.

BACKGROUND The occurrence of acute rejection in orthotopic liver transplantation is unpredictable. The role of cytokines in the process of rejection is not entirely clear. We investigated polymorphisms in the genes encoding tumor necrosis factor (TNF)-alpha, interleukin (IL)-10, and transforming growth factor (TGF)-beta1, which affect the amount of cytokine produced in vitro, in a liver transplant population to determine any association with acute rejection. METHOD DNA was extracted from whole blood of liver transplant patients. After amplification with polymerase chain reactions, the polymorphisms at TNF-alpha -308, IL-10 -1082, and TGF-beta1 +869 and +915 were determined using sequence-specific oligonucleotide probes. Acute cellular rejection was a clinical and histological diagnosis. RESULTS Acute cellular rejection requiring treatment occurred in 68 (48%) of 144 patients. Acute cellular rejection was significantly associated with the TNF-alpha -308 A/A genotype (P<0.02). There was no significant association with either IL-10 or TGF-beta1 polymorphisms in acute rejection. CONCLUSION Patients with a homozygous TNF-alpha -308 genotype A/A are more likely to suffer from acute cellular rejection after liver transplantation.

The systemic inflammatory response syndrome is predictive of renal dysfunction in patients with non-paracetamol-induced acute liver failure

Background: Although renal dysfunction is a common complication of acute liver failure (ALF) with significant prognostic implications, the pathophysiological mechanisms remain unclear. The current hypothesis suggests that the renal dysfunction may mirror the hepatorenal syndrome of cirrhosis. However, ALF has distinct clinical characteristics and the circulatory derangement may be more comparable with sepsis. Objectives: To examine the relationship between the systemic inflammatory response syndrome (SIRS) and renal dysfunction in ALF, and to identify additional risk factors for renal dysfunction. Methods: A single-centre retrospective study of 308 patients with ALF was carried out. Renal dysfunction was defined according to the RIFLE criteria for acute kidney injury. Results: 67% of patients developed renal dysfunction. On univariate analysis, renal dysfunction patients were more likely to be hypothermic (p = 0.010), had a faster heart rate (p<0.001), a higher white cell count (p = 0.001) and a lower PaCO2 (p = 0.033). 78% of renal dysfunction patients and 53% of non-renal dysfunction patients had SIRS (p<0.001). On multivariate analysis, the risk factors for renal dysfunction were age (p = 0.024), fulfilled Kings College Hospital prognostic criteria (p<0.001), hypotension (p<0.001), paracetamol-induced ALF (p<0.001), infection (p = 0.077) and SIRS (p = 0.017). SIRS remained an independent predictor of renal dysfunction in the subgroup of patients with non-paracetamol-induced ALF (n = 91, p = 0.001). In contrast, in patients with paracetamol-induced ALF (n = 217), no relationship between SIRS and renal dysfunction was demonstrated (p = 0.373). Conclusion: SIRS is strongly associated with the development of renal dysfunction in patients with non-paracetamol-induced ALF. It is proposed that the systemic inflammatory cascade plays a key role in its pathogenesis.

The UK-PBC risk scores: Derivation and validation of a scoring system for long-term prediction of end-stage liver disease in primary biliary cholangitis

The biochemical response to ursodeoxycholic acid (UDCA)—so‐called “treatment response”—strongly predicts long‐term outcome in primary biliary cholangitis (PBC). Several long‐term prognostic models based solely on the treatment response have been developed that are widely used to risk stratify PBC patients and guide their management. However, they do not take other prognostic variables into account, such as the stage of the liver disease. We sought to improve existing long‐term prognostic models of PBC using data from the UK‐PBC Research Cohort. We performed Coxs proportional hazards regression analysis of diverse explanatory variables in a derivation cohort of 1,916 UDCA‐treated participants. We used nonautomatic backward selection to derive the best‐fitting Cox model, from which we derived a multivariable fractional polynomial model. We combined linear predictors and baseline survivor functions in equations to score the risk of a liver transplant or liver‐related death occurring within 5, 10, or 15 years. We validated these risk scores in an independent cohort of 1,249 UDCA‐treated participants. The best‐fitting model consisted of the baseline albumin and platelet count, as well as the bilirubin, transaminases, and alkaline phosphatase, after 12 months of UDCA. In the validation cohort, the 5‐, 10‐, and 15‐year risk scores were highly accurate (areas under the curve: >0.90). Conclusions: The prognosis of PBC patients can be accurately evaluated using the UK‐PBC risk scores. They may be used to identify high‐risk patients for closer monitoring and second‐line therapies, as well as low‐risk patients who could potentially be followed up in primary care. (Hepatology 2016;63:930–950)

Impact of primary biliary cirrhosis on perceived quality of life: The UK-PBC national study†‡§

Primary biliary cirrhosis (PBC) has a complex clinical phenotype, with debate about the extent and specificity of frequently described systemic symptoms such as fatigue. The aim of this study was to use a national patient cohort of 2,353 patients recruited from all clinical centers in the UK to explore the impact of disease on perceived life quality. Clinical data regarding diagnosis, therapy, and biochemical status were collected and have been reported previously. Detailed symptom phenotyping using recognized and validated symptom assessment tools including the PBC‐40 was also undertaken and is reported here. Perception of poor quality of life and impaired health status was common in PBC patients (35% and 46%, respectively) and more common than in an age‐matched and sex‐matched community control group (6% and 15%, P < 0.0001 for both). Fatigue and symptoms of social dysfunction were associated with impaired perceived quality of life using multivariate analysis. Fatigue was the symptom with the greatest impact. Depression was a significant factor, but appeared to be a manifestation of complex symptom burden rather than a primary event. Fatigue had its greatest impact on perceived quality of life when accompanied by symptoms of social dysfunction, suggesting that maintenance of social networks is critical for minimizing the impact of fatigue. Conclusion: The symptom burden in PBC, which is unrelated to disease severity or ursodeoxycholic acid response, is significant and complex and results in significant quality of life deficit. The complexity of symptom burden, and its lack of relation to disease severity and treatment response, suggest that specific approaches to symptom management are warranted that address both symptom biology and social impact. (Hepatology 2013;58:‐)

polymorphisms in tumour necrosis factor α, interleukin-10 and transforming growth factor β1 genes and end-stage liver disease

OBJECTIVE: To determine any relationship between polymorphisms in the genes encoding tumour necrosis factor alpha (TNFalpha), interleukin-10 (IL-10) and transforming growth factor beta1 (TGFbeta1) and end-stage liver disease. METHODS: Whole-blood samples were taken from patients attending the Scottish Liver Transplant Unit with end-stage liver disease (primary biliary cirrhosis, n = 61; alcoholic liver disease, n = 25; primary sclerosing cholangitis, n = 17; viral disease, n = 8; type 1 auto-immune hepatitis, n = 8; acute liver failure, n = 20). DNA was extracted and the polymorphisms at positions TNF -308, IL-10 -1082 and TGFbeta1 +869 and +915 were determined using sequence-specific oligonucleotide probes. Samples were also analysed from normal healthy controls. RESULTS: There was a significant difference between patients with primary sclerosing cholangitis and healthy controls, with 65% of patients (11/17) possessing at least one TNF2 allele (A at position -308) compared with 38% of controls (P = 0.02). Four of the eight patients with auto-immune hepatitis were homozygous for TNF2 while the other four were heterozygous (P = 0.001). No significant difference between controls and patients was seen in polymorphisms for IL-10 or TGFbeta1. No association between genotype and Childs class was found in primary biliary cirrhosis. CONCLUSION: Patients with primary sclerosing cholangitis and auto-immune hepatitis are more likely to possess TNF2 than normal controls. This allele has been associated with an increased production of TNFalpha in vitro and may indicate a predisposition to these inflammatory conditions.

Colorectal disease in liver allograft recipients: a clinicopathological study with follow-up

Objective To determine the spectrum and outcome of colorectal diseases occurring in adult liver allograft recipients. Design A retrospective cohort analysis of clinical, microbiological and histopathological data regarding colorectal disease. Patients Forty three out of 302 adult primary liver allograft recipients were transplanted and followed up (at median 42 months) at a tertiary referral centre/teaching hospital. Results Out of 302 patients, 43 (14%) were investigated (by endoscopy and/or laparotomy) for symptoms of colorectal disease after orthotopic liver transplantation. The symptoms were: diarrhoea (n = 31); per-rectal bleeding (n = 5); and symptoms relating to pre-transplant ulcerative colitis (n = 7). Among the patients without known ulcerative colitis, per-rectal bleeding occurring early after orthotopic liver transplantation was most commonly caused by cytomegalovirus colitis and carried a poor prognosis. Excluding ulcerative colitis, the commonest causes of diarrhoea were Clostridium difficile, cytomegalovirus infection and medications, particularly during the first 2 months after orthotopic liver transplantation. No cases of colorectal graft-versus-host disease, cryptosporidiosis, amoebiasis, atypical mycobacterial infection or post-transplant lymphoproliferative disease were demonstrated. The activity of pre-transplant ulcerative colitis was unchanged or increased after orthotopic liver transplantation. Two further patients developed new-onset ulcerative colitis after orthotopic liver transplantation. Conclusions Ulcerative colitis, C. difficile, cytomegalovirus infection and medications are the commonest colorectal causes of morbidity after orthotopic liver transplantation. Adult liver allograft recipients are, however, unlikely to show certain large bowel diseases encountered in other immunosuppressed groups. Amongst non-ulcerative colitis patients, those presenting with diarrhoea show a good outcome with appropriate management, whereas those with per-rectal bleeding have a more guarded prognosis.

The impact of liver transplantation on the phenotype of primary biliary cirrhosis patients in the UK-PBC cohort

BACKGROUND & AIMS Liver transplantation improves survival in end-stage primary biliary cirrhosis (PBC), but the benefit for systemic symptoms including fatigue is less clear. The aim of this study was to utilise the comprehensive UK-PBC Research Cohort, including 380 post-transplant patients and 2300 non-transplanted patients, to answer key questions regarding transplantation for PBC. METHODS Cross-sectional study of post-transplant PBC patients and case-matched non-transplanted patients. Detailed clinical information was collected, together with patient systemic symptom impact data using validated assessment tools. RESULTS Over 25% of patients in the transplant cohort were grafted within 2 years of PBC diagnosis suggesting advanced disease at presentation. Transplanted patients were significantly younger at presentation than non-transplanted (mean 7 years) and >35% of all patients in the UK-PBC cohort who presented under 50 years had already undergone liver transplantation at the study censor point (>50% were treatment failures (post-transplant or unresponsive to UDCA)). Systemic symptom severity (fatigue and cognitive symptoms) was identical in female post-transplant patients and matched non-transplanted controls and unrelated to disease recurrence or immunosuppression type. In males, symptoms were worse in transplanted than in non-transplanted patients. CONCLUSIONS Age at presentation is a major risk factor for progression to transplant (as well as UDCA non-response) in PBC. Although both confirmatory longitudinal studies, and studies utilising objective as well as subjective measures of function, are needed if we are to address the question definitively, we found no evidence of improved systemic symptoms after liver transplantation in PBC and patients should be advised accordingly. Consideration needs to be given to enhancing rehabilitation approaches to improve function and life quality after liver transplant for PBC.

Three-dimensional representation software as image enhancement tool in small-bowel capsule endoscopy: a feasibility study.

BACKGROUND Three-dimensional imaging in capsule endoscopy is not currently feasible due to hardware limitations. However, software algorithms that enable three-dimensional reconstruction in capsule endoscopy are available. METHODS Feasibility study. A phantom was designed to test the accuracy of three-dimensional reconstruction. Thereafter, 192 small-bowel capsule endoscopy images (of vascular: 50; inflammatory: 73; protruding structures: 69) were reviewed with the aid of a purpose-built three-dimensional reconstruction software. Seven endoscopists rated visualisation improved or non-improved. Subgroup analyses performed for diagnostic category, diagnosis, image surface morphology and colour and SBCE equipment used (PillCam(®) vs. MiroCam(®)). RESULTS Overall, phantom experiments showed that the three-dimensional reconstruction software was accurate at 90% of red, 70% of yellow and 45% of white phantom models. Enhanced visualisation for 56% of vascular, 23% of inflammatory and <10% of protruding structures was noted (P=0.007, 0.172 and 0.008, respectively). Furthermore, three-dimensional software application enhanced 53.7% of red, 21.8% of white, 17.3% of red and white, and 9.2% of images of lesions with colour similar to that of the surrounding mucosa, P<0.0001. CONCLUSIONS Application of a three-dimensional reconstruction software in capsule endoscopy leads to image enhancement for a significant proportion of vascular, but less so for inflammatory and protruding lesions. Until optics technology allows hardware-enabled three-dimensional reconstruction, it seems a plausible alternative.

Serum phosphate is not a reliable early predictor of outcome in paracetamol induced hepatotoxicity

We read with interest the recent study by Chung, Sitrin, Te regarding serum phosphate (PO4) levels as a predictor of clinical outcome in fulminant hepatic failure.1 This study did not specify the timing of serum PO4 measurement and concluded better prognosis in low serum PO4 patients. A similar prospective study by Schmidt and Dalhoff2 investigated the outcome in paracetamol poisoning, which is the most common cause of acute liver failure in North America and Europe. This study concluded that a PO4 concentration of 1.2 mmol/L at 48 to 96 hours after overdose was highly specific and sensitive and had a greater overall predictive value than King’s College Hospital criteria.3 We carried out a retrospective analysis in our cohort of patients with paracetamol poisoning referred to the Scottish Liver Transplant Unit during the period 1992 to 2002. Four hundred fifty-four patients were referred with paracetamol-induced hepatotoxicity within the 10year period. We selected 117 patients with both the time from paracetamol ingestion to N-acetyl cysteine administration and at least one PO4 measurement available at 48 to 96 hours postoverdose. The median time from ingestion to hospital admission was 24 hours (range, 5–96 hours) and all patients were given intravenous N-acetyl cysteine upon arrival at the hospital. There were 58 (49.6%) spontaneous survivors who did not fulfil the KCH criteria. Fifty-nine (50.4%) patients met the KCH criteria of whom 11 were transplanted and the other 48 died without a liver transplant. Out of 117 patients, 38 patients had PO4 measurements on both day 2 (48 to 72 hours postoverdose) and day 3 (72 to 96 hours postoverdose), 36 patients had PO4 measurement available only on day 2, and 43 patients only on day 3. A corresponding serum creatinine was also recorded. Phosphate concentrations were significantly higher in nonsurvivors or transplanted patients than survivors on day 2 (1.32 1.06 mmol/L vs. 0.66 0.26 mmol/L, respectively; Mann-Whitney: P 0.001) but were not significantly higher on day 3 (0.98 0.81 mmol/L vs. 0.64 0.38 mmol//L, respectively; MannWhitney: P 0.16). The discriminant PO4 value of 1.2 mmol/L reported by Schmidt and Dalhoff was found to have a poor negative predictive value as 66.7% (22/33) of measureFigure 1. Serum phosphate (PO4) levels on days 2 and 3, according to King’s College Hospital (KCH) criteria. Dotted lines indicate 1.2 mmol/L. A: Day 2 post overdose. B: Day 3 post overdose.