Background and Aims: Herbal and dietary supplements (HDS) have been associated with liver injury and severe liver disease, including acute liver failure (ALF), collectively referred to as HDS-induced ALF (HDS-ALF). With the global increase in HDS usage, reports of HDS-ALF cases have also risen. Methods: Genetic analysis was conducted using whole exome sequencing data from 23 HDS-ALF cases, with population controls sourced from the 1000 Genomes Project. Single-nucleotide polymorphisms (SNPs) with chi-square test P values less than 5 × 10−8 and stable allele frequencies across different ethnicities and healthy controls were considered statistically significant. Variants were also analyzed based on supplement type (herbal vs dietary) and sex (female vs male). Results: Thirty-three SNPs were statistically significant (P < 5 × 10−8), predominantly located in human leukocyte antigen (HLA) genes (HLA-A, HLA-B, HLA-DQA1, and HLA-DRB1) and estrogen-related receptor alpha (ESRRA). The top SNPs, including rs17879990 (HLA-A), rs1131500 (HLA-B), and rs1161801407 (HLA-DRB1), showed strong associations. In subgroup analyses, 4 SNPs were significant in the herbal product group and 3 in the dietary supplement group. Gender-based analyses revealed 15 significant SNPs in females and 8 in males, particularly 7 SNPs within HLA-B and HLA-DQA1, appeared female-specific. Conclusion: This study identifies specific HLA and ESRRA gene variants as genetic risk factors for HDS-ALF, with significant associations observed across HDS exposures. The findings suggest potential cross-gender risks, particularly for certain HLA and ESRRA SNPs, while highlighting female-specific vulnerabilities within HLA-B and HLA-DQA1 variants.

BACKGROUND AND AIMS:Acute liver failure (ALF) is a serious condition, typically in individuals without prior liver disease. Drug-induced ALF (DIALF) constitutes a major portion of ALF cases. Our research aimed to identify potential genetic predispositions to DIALF. METHODS:We analysed the potential genetic variants associated with DIALF using the whole exome sequencing data from 75 cases, including 40 non-Finnish European cases in the pilot study. Chi-square tests were performed for case-control analysis against the 1000 genomes project as the control. A replication study of 44 DIALF cases that included 24 non-Finnish Europeans was conducted to validate candidate variants. The association between clinical phenotype and genotypes was analysed using one-way analysis of variance. RESULTS:Eight variants (rs561037, rs561042, rs608339, rs655260, rs1142886, rs1142888, rs1142889 and rs1142890) in the guanylate binding protein 4 (GBP4) were significantly associated with DIALF in non-Finnish Europeans in the pilot study and confirmed in the replication study. Rs561037 and rs561042 were highly significant with the lowest allele frequencies in both pilot and replication studies. An association was also found between these variants and milder clinical outcomes, indicated by lower peak levels of ALT, AST and higher Karnofsky performance scores. CONCLUSION:Our study identified eight GBP4 missense variants linked to a lower risk of DIALF in the non-Finnish European population. The GBP4 protein, activated by interferon-gamma, plays a critical role in innate immunity. These findings suggest that GBP4 variants might influence immune and inflammatory responses in DIALF, though further studies are needed to elucidate the underlying mechanisms.

Acetaminophen (APAP) hepatotoxicity and ischemic hepatic injury (IH) demonstrate remarkably similar biochemical patterns. Deciding between these two etiologies in the setting of acute liver failure (ALF) can be challenging. We reviewed all cases in the Acute Liver Failure Study Group (ALFSG) registry where these diagnoses were considered, to determine reasons for, and frequency of, difficulties making these diagnoses. We hypothesized that the newly developed APAP-CYS adduct assay could help in discerning the correct diagnosis. Among 3364 patients with ALF or acute liver injury (ALI: INR ≥ 2.0 but without encephalopathy) between 1998 and 2019, 1952 (58

BACKGROUND:The etiology of acute liver failure (ALF) remains one of the most important factors in determining prognosis and predicting outcomes. In a significant proportion of ALF cases, however, the etiology remains unknown and is categorized as indeterminate ALF (IND-ALF). In this study, we summarize findings from patients with IND-ALF from 32 transplant centers across the United States, and we compare laboratory, prognostic, and outcome data for patients with IND-ALF. METHODS:Between 1998 and 2019, 3364 adult patients with ALF or acute liver injury (ALI) from 32 liver transplant centers were enrolled in the ALFSG registry. The primary clinical outcome of interest was 21-day transplant-free survival (TFS). RESULTS:Of the 3364 patients enrolled in the ALFSG registry, 3.4 % (n = 114) were adjudicated as true indeterminate. On multivariate analysis, patients with a lower bilirubin, lower INR, lack of use of mechanical ventilation and no clinical features of coma at baseline had a higher odds ratio of transplant free survival. The number of deaths were similar between patients with true-IND ALF versus patients with indeterminable ALF (29.8% vs. 27.2%), with almost half of the patients requiring liver transplant (42.1% vs. 45.7%). CONCLUSION:We illustrate the poor prognoses that true-IND-ALF and indeterminable ALF carry and the need for emergency liver transplantation in most cases.

There has been a growing interest in identifying prognostic biomarkers that alone or with available prognostic models (King's College Criteria, KCC; MELD and ALFSG Prognostic Index) would improve prognosis in acute liver failure (ALF) patients being assessed for liver transplantation. The Acute Liver Failure Study Group (ALFSG) has evaluated 15 potential prognostic biomarkers: serum AFP; apoptosis-associated proteins; serum actin-free Gc-globulin; serum glycodeoxycholic acid; sRAGE/RAGE ligands; plasma osteopontin; circulating MBL, M-, L-, H-ficolin and CL-1; plasma galectin-9; serum FABP1; serum Lct2; miRNAs; factor V; thrombocytopenia, and sCD163. The ALFSG also has reported on 4 susceptibility biomarkers: keratins 8 and 18 (K8/K18) gene variants; polymorphisms of genes encoding putative APAP-metabolizing enzymes ( UGT1A1 , UGT 1A0 , UGT 2B15 , SULT1A1 , CYP2E1 , and CYP3A5 ) as well as CD44 and BHMT1 ; single nucleotide polymorphisms (SNPs) of genes associated with human behavior, rs2282018 in the arginine vasopressin ( AVP ) gene and rs11174811 in the AVP receptor 1A gene. Finally, rs2277680 of the CSCL16 gene in HBV-ALF patients. In conclusion, we have reviewed the prognostic and susceptibility biomarkers studied by the ALFSG. We suggest that a better approach to predicting the clinical outcome of an ALF patient will require a combination of biomarkers of pathogenic processes such as cell death, hepatic regeneration, and degree of inflammation that could be incorporated into prognostic models such as KCC, MELD or ALFSG PI.

Autoimmune hepatitis is a common cause of acute liver failure. Treatment includes steroids for acute liver injury and liver transplantation in those who fail to respond or develop acute liver failure. The aim of this study is to further characterize acute liver failure secondary to autoimmune hepatitis and identify variables that predict 21-day transplant-free survival. This study included adults hospitalized with acute liver failure enrolled in the Acute Liver Failure Study Group Registry between 1998 and 2019 from 32 centers within the US. The etiology of all cases was reviewed by the Adjudication Committee, and all cases identified as autoimmune hepatitis were included. Acute liver injury was defined as an INR ≥2.0 without encephalopathy and acute liver failure as INR ≥ 1.5 with encephalopathy. Laboratory and clinical data were reviewed. Variables significantly associated with 21-day transplant-free survival were used to develop a multivariable logistic regression model.  A total of 193 cases of acute liver failure secondary to autoimmune hepatitis were identified and reviewed. There were 161 patients (83.4%) diagnosed with acute liver failure on enrollment, and 32 (16.6%) developed acute liver failure during hospitalization. At 21 days, 115 (59.6%) underwent liver transplantation, 28 (14.5%) had transplant-free survival, and 46 (23.8%) died before liver transplantation. Higher admission values of bilirubin, INR, and coma grade were associated with worse outcomes. A prognostic index incorporating bilirubin, INR, coma grade, and platelet count had a concordance statistic of 0.84. Acute liver failure secondary to autoimmune hepatitis is associated with a high short-term mortality. We developed a model specifically for autoimmune hepatitis that may be helpful in predicting 21-day transplant-free survival and early identification of patients in need of expedited liver transplant evaluation.

INTRODUCTION: Indeterminate acute liver failure (IND-ALF) is a rare clinical syndrome with a high mortality rate. Lacking a known etiology makes rapid evaluation and treatment difficult, with liver transplantation often considered as the only therapeutic option. Our aim was to identify genetic variants from whole exome sequencing data that might be associated with IND-ALF clinical outcomes. METHODS: Bioinformatics analysis was performed on whole exome sequencing data for 22 patients with IND-ALF. A 2-tier approach was used to identify significant single-nucleotide polymorphisms (SNPs) associated with IND-ALF clinical outcomes. Tier 1 identified the SNPs with a higher relative risk in the IND-ALF population compared with those identified in control populations. Tier 2 determined the SNPs connected to transplant-free survival and associated with model for end-stage liver disease serum sodium and Acute Liver Failure Study Group prognostic scores. RESULTS: Thirty-one SNPs were found associated with a higher relative risk in the IND-ALF population compared with those in controls, of which 11 belong to the human leukocyte antigen (HLA) class II genes but none for the class I. Further analysis showed that 5 SNPs: rs796202376, rs139189937, and rs113473719 of HLA-DRB5; rs9272712 of HLA-DQA1; and rs747397929 of IDO1 were associated with a higher probability of IND-ALF transplant-free survival. Using 3 selected SNPs, a model for the polygenic risk score was developed to predict IND-ALF prognoses, which are comparable with those by model for end-stage liver disease serum sodium and Acute Liver Failure Study Group prognostic scores. DISCUSSION: Certain gene variants in HLA-DRB5, HLA-DQA1, and IDO1 were found associated with IND-ALF transplant-free survival. Once validated, these identified SNPs may help elucidate the mechanism of IND-ALF and assist in its diagnosis and management.

One promising goal for utilizing the molecular information circulating in biofluids is the discovery of clinically useful biomarkers. Extracellular RNAs (exRNAs) are one of the most diverse classes of molecular cargo, easily assayed by sequencing and with expressions that rapidly change in response to subject status. Despite diverse exRNA cargo, most evaluations from biofluids have focused on small RNA sequencing and analysis, specifically on microRNAs (miRNAs). Another goal of characterizing circulating molecular information, is to correlate expression to injuries associated with specific tissues of origin. Biomarker candidates are often described as being specific, enriched in a particular tissue or associated with a disease process. Likewise, miRNA data is often reported to be specific, enriched for a tissue, without rigorous testing to support the claim. Here we provide a tissue atlas of small RNAs from 30 different tissues and three different blood cell types. We analyzed the tissues for enrichment of small RNA sequences and assessed their expression in biofluids: plasma, cerebrospinal fluid, urine, and saliva. We employed published data sets representing physiological (resting vs. acute exercise) and pathologic states (early- vs. late-stage liver fibrosis, and differential subtypes of stroke) to determine differential tissue-enriched small RNAs. We also developed an online tool that provides information about exRNA sequences found in different biofluids and tissues. The data can be used to better understand the various types of small RNA sequences in different tissues as well as their potential release into biofluids, which should help in the validation or design of biomarker studies.

Hypophosphatemia is a common and dangerous complication of acute liver failure (ALF) of various etiologies. While various mechanisms for ALF-associated hypophosphatemia have been proposed including high phosphate uptake into regenerating hepatocytes, acetaminophen (APAP)-associated hypophosphatemia was linked to renal phosphate wasting, and APAP-induced renal tubular injury was proposed as underlying mechanism. We studied 30 normophosphatemic and 46 hypophosphatemic (serum phosphate < 2.5 mg/dL) patients from the Acute Liver Failure Study Group registry with APAP- or non-APAP-induced ALF. Since kidney injury affects phosphate excretion, patients with elevated serum creatinine (>1.2 mg/dL) were excluded. Maximal amount of renal tubular phosphate reabsorption per filtered volume (TmP/GFR) was calculated from simultaneous serum and urine phosphate and creatinine levels to assess renal phosphate handling. Instead of enhanced renal phosphate reabsorption as would be expected during hypophosphatemia of non-renal causes, serum phosphate was positively correlated with TmP/GFR in both APAP- and non-APAP-induced ALF patients (R2 = 0.66 and 0.46, respectively; both P < 0.0001), indicating renal phosphate wasting. Surprisingly, there was no evidence of kidney damage based on urinary markers including neutrophil gelatinase-associated lipocalin and cystatin C even in the APAP group. Additionally, there was no evidence that the known serum phosphatonins parathyroid hormone, fibroblast growth factor 23, and α-Klotho contribute to the observed hypophosphatemia. We conclude that the observed hypophosphatemia with renal phosphate wasting in both APAP- and non-APAP-mediated ALF is likely the result of renal tubular phosphate leak from yet-to-be identified factor(s) with no evidence for proximal tubular damage or contribution of known phosphatonins.

We have read with great interest the letter by Heddar and Misrachi and have drafted the following response. Our study used gnomAD version 2.1.1 for hg38 genome build to annotate these variants because this was the most current version of gnomAD available during the course of this study, version 3 was published in October 2019, whereas this study was submitted to Clinical and Translational Gastroenterology in June 2019 and was published online in October 2019. We stand by our use of version 2, and we would like to emphasize an insight regarding gnomAD that Heddar and Misrachi seemed to have overlooked. In the FAQ page of this software, it recommends not switching from version 2: “The gnomAD v2 call set contains fewer whole genomes than v3 but also contains a very large number of exomes that substantially increase its power as a reference in coding regions. Therefore, gnomAD v2 is still our recommended dataset for most coding regions analyses” (https://gnomad.broadinstitute.org/faq#should-i-switch-to-the-latest-version-of-gnomad). This is very pertinent because we performed whole exome sequencing in our study. Furthermore, this version has reported 4 of 12 variants at very low allele frequency (last column in table below), contrary to the high AF suggested by Heddar and Misrachi. The 12 variants corresponding to 11 genes were represented in a significantly higher prevalence in our study population based on the Fisher exact test. All variants were annotated with allele frequencies from the following databases: ExAC (r0.3_GRCh38: 60,706 unrelated individuals from 17 disease-specific and population genetic studies, excluding individuals affected by a severe pediatric disease) 1000G (20130502_GRCh38: integrated set of SNPs, indels, MNPs, long insertions and deletions, copy number variations, and other types of structural variations discovered and genotyped in 2,504 unrelated individuals), and Mayo Clinic Biobank (funded by a Mayo Clinic initiative for Individualized Medicine to assist investigators throughout the institution in obtaining “normal” samples to serve as controls for their patient populations, 982 whole genome samples) Furthermore, as explained in our study, we divided 26 patients into the following 2 groups: 8 patients who survived spontaneously from their acute liver failure (ALF) episode of indeterminate etiology and 18 patients with the same diagnosis who died or underwent liver transplant. The 12 variants reported in Table 1 of our study were found to have significant group-specific (spontaneous survivors vs death or liver transplantation) variant distributions by performing genetic association analysis using the Rvtests package (the Fisher exact association model was used to determine significance of variant association statistics).Table 1.: Variants found to be significantly associated with indeterminate acute liver failure in our 26 patientsGiven the small cohort size of our pilot study, we intend to expand our study to a larger population with ALF of indeterminate etiology and compare their variants distribution with patients with ALF associated with viral hepatitis, ALF associated with drug-induced liver injury, and autoimmune ALF. We hope that these studies may provide an insight into the mechanism(s) underlying ALF and specifically ALF with indeterminate etiology. CONFLICTS OF INTEREST Guarantor of the article: Jorge Rakela, MD. Specific author contributions: J.R. is accepting full responsibility for the conduct of the study. He had access to the data and had control of the decision to publish. J.R., he led the group in planning the response to the letter to the editor, interpreting data, and drafting the response to the letter to the editor. M.K.D. reviewed collected data and the analysis performed using gnomAD version 2 and 3. S.B., expert in bioinformatics analysis reviewed our response and verify accuracy of data. Ms. Dehankar and Mr. Baheti participated in the writing and editing of the letter to the editor as well. Financial support: Grant 18-0011260; Mayo Clinic Center for Individualized Medicine. Potential competing interests: None to report.

On behalf of the authors of our manuscript, we agree in that a lower incidence of hepatocellular carcinoma (HCC) in the patients with large spontaneous portosystemic shunts (SPSSs) was noted in the study, however we were careful in actually reporting a potentially protective effect of SPSS on HCC occurrence. We noted this as an unexpected finding and hope the readership can potentially consider further evaluation in this matter.

Spontaneous portosystemic shunts (SPSSs) have been associated with worse clinical outcomes in the pre-liver transplantation (LT) setting, but little is known about their post-LT impacts. Our aim was to compare LT candidates with and without SPSSs and assess the impact of SPSSs on patient mortality and graft survival in the post-LT setting. Patients 18 years or older with abdominal imaging done prior to LT were included. Exclusion criteria were the presence of pre-LT surgical shunts, LT indications other than cirrhosis, and combined solid organ transplantations. SPSSs were classified as absent, small, or large according to their maximum diameter (8 mm). Multiple variables that could influence the post-LT course were extracted for analysis. Patient and graft survival were estimated using the Kaplan-Meier method and were compared between groups using a log-rank test. The project received institutional review board approval. We extracted data from 326 patients. After comparing patients without SPSS or with small or large SPSSs, no statistical difference was found for overall patient survival: no SPSS (n = 8/63), reference; small SPSS (n = 18/150), hazard ratio (HR), 1.05 (95% confidence interval [CI], 0.45-2.46); and large SPSS (n = 6/113), HR, 0.60 (95% CI, 0.20-1.78); P = 0.20. Also, no difference was found for graft survival: no SPSS (n = 11/63), reference; small SPSS (n = 21/150), HR, 0.80 (95% CI, 0.38-1.70); large SPSS (n = 11/113), HR, 0.59 (95% CI, 0.25-1.40); P = 0.48. Similarly, no statistical significance was found for these variables when comparing if the graft used was procured from a donation after circulatory death donor versus a donation after brain death donor. In conclusion, the previously described association between SPSSs and worse clinical outcomes in pre-LT patients seems not to persist once patients undergo LT. This study suggests that no steps to correct SPSS intraoperatively are necessary.

INTRODUCTION: The etiology of acute liver failure (ALF) remains an important prognostic factor. The Acute Liver Failure Study Group recently reported that 150 of 2,718 adult patients with ALF (5.5%) had an indeterminate etiology. Our aim was to use whole exome sequencing to identify genetic variants associated with phenotypic, biochemical, and histologic features among patients with indeterminate ALF. METHODS: This effort has defined a cohort of well-pedigreed patients with indeterminate ALF; DNA samples extracted from whole blood samples were obtained from 26 respective patients with indeterminate ALF. These samples were kept at the Acute Liver Failure Study Group repository at the NIDDK, Bethesda. Whole exome sequencing and bioinformatics analysis were performed at the Mayo Clinic Center of Individualized Medicine in Rochester, MN. RESULTS: Of the 26 patients, 8 survived spontaneously, 6 died, and 12 underwent a liver transplantation; all those transplanted were alive at 21 days after enrollment in the study. Twenty-two of the 26 patients presented as ALF. We found 12 variants associated with 11 genes. The most common variant was rs4940595 in the SERPINB11 gene which was found in 23 of the 26 patients. This variant had a stop codon; no reports of disorders have been associated with this variant. The next most commonly found variant was rs1135840 in the CYP2D6 gene; this mutation is a missense_variant and has been reported to be associated with hepatotoxicity of antituberculous therapy. None of our patients were receiving this therapy. We also found a significant asymmetric distribution of rs1800754 of the CYP2D7 gene and rs1135840 of the CYP2D6 gene between patients who survived spontaneously (75%) and those who died or underwent liver transplantation (30.5% and 25%, respectively). DISCUSSION: We found 12 variants of 11 genes significantly associated with ALF among adults with indeterminate etiology. We also found a significant asymmetric distribution of 2 variants belonging to the CYP2D7 and CYP2D6 genes, respectively, between those who survived spontaneously and those who died or underwent liver transplantation. The 2 most common variants, rs4940595 and rs1135840, of the SERPINB11 and CYP2D6 genes, respectively, found in our patients with ALF have been described as potentially important in the adaptive response combating the emergence of infectious diseases and associated with hepatotoxicity of antituberculous therapy, respectively. Our findings need to be expanded to include more patients with indeterminate ALF as well as viral, drug toxicity, and autoimmune etiologies to determine whether our findings are associated with the specific etiology, indeterminate, or with the overall ALF syndrome itself.