Portal hypertension (PH) in liver cirrhosis leads to increased gut permeability and the translocation of bacteria across the gut–liver axis. Microbial DNA has recently been detected in different blood compartments; however, this phenomenon has not been thoroughly analyzed in PH. This study aimed to explore circulating bacterial DNA signatures, inflammatory cytokines, and gut permeability markers in different blood compartments (peripheral and hepatic veins) of patients with cirrhosis and PH. The 16S rRNA blood microbiome profiles were determined in 58 patients with liver cirrhosis and 46 control patients. Taxonomic differences were analyzed in relation to PH, liver function, inflammatory cytokines, and gut permeability markers. Circulating plasma microbiome profiles in patients with cirrhosis were distinct from those of the controls and were characterized by enrichment of Comamonas, Cnuella, Dialister, Escherichia/Shigella , and Prevotella and the depletion of Bradyrhizobium, Curvibacter, Diaphorobacter, Pseudarcicella , and Pseudomonas . Comparison of peripheral and hepatic vein blood compartments of patients with cirrhosis did not reveal differentially abundant taxa. Enrichment of the genera Bacteroides, Escherichia/Shigella , and Prevotella was associated with severe PH (SPH) in both blood compartments; however, circulating microbiome profiles could not predict PH severity. Escherichia/Shigella and Prevotella abundance was correlated with IL-8 levels in the hepatic vein. In conclusion, we demonstrated a distinct circulating blood microbiome profile in patients with cirrhosis, showing that specific bacterial genera in blood are marginally associated with SPH, Model for End-Stage Liver Disease score, and inflammation biomarkers; however, circulating microbial composition failed to predict PH severity.

Background & Aims: Genome-wide association studies have revealed an association between the risk of developing liver fibrosis or cirrhosis and the single nucleotide polymorphisms (SNPs) of the PNPLA3, RNF7, MERTK and PCSK7 genes. We aimed to validate these results in an Eastern European population.Methods: We evaluated the associations between the PNPLA3 (rs738409), RNF7 (rs16851720), MERTK (rs4374383) and PCSK7 (rs236918) variants and liver fibrosis and cirrhosis in a series of consecutive patients recruited at the Department of Gastroenterology, Lithuanian University of Health Sciences Hospital, during the period 2012-2015. The study included 317 individuals with liver cirrhosis, 154 individuals with liver fibrosis, and 498 controls. The studied SNPs were determined using RT-PCR TaqMan assays.Results: MERTK and PCSK7 SNPs were not associated with liver fibrosis or cirrhosis. The PNPLA3 SNP rs738409 was associated with a higher risk of developing liver fibrosis (aOR: 1.65, P=0.001) and cirrhosis (aOR: 1.92, P=5.57*10-7). PNPLA3 genotypes were also associated with higher risk of developing liver fibrosis and cirrhosis in dominant (aOR: 1.98, P=2.20*10-5; aOR: 1.67, P=0.008, respectively) and recessive (aOR: 3.94, P=5.16*10-5; aOR: 3.02, P=0.003, respectively) models. RNF7 rs16851720 was associated with liver cirrhosis comparing CC vs. AA + CA genotypes (aOR: 0.26, P=0.020).Conclusion: Our study showed that PNPLA3 rs738409 and RNF7 rs16851720 confer an increased risk of developing liver fibrosis and cirrhosis in this Eastern European population, while the MERTK and PCSK7 SNPs are not associated with these conditions.Abbreviations: GWAS: Genome-wide association studies; HBV: hepatitis B virus; HCV: hepatitis C virus; HH: hereditary hemochromatosis; MERTK: proto-oncogene tyrosine-protein kinase MER; NAFLD: non-alcoholic fatty liver disease; PCSK7: proprotein convertase 7; PNPLA3: patatin-like phospholipase domain containing 3; RNF7: SAG sensitive to apoptosis gene; SNP: single nucleotide polymorphism.

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Introduction: Gastric cancer (GC) diagnosis in late stages and high mortality rates are the main issues that require new noninvasive molecular tools. We aimed to assess somatic mutational profiles in GC tissue and plasma cell-free DNA (cfDNA), evaluate their concordance rate, and analyze the role of multilayer molecular profiling to predict disease state and prognosis. Methods: Treatment-naive GC patient group (n = 29) was selected. Whole exome sequencing (WES) of GC tissue was performed, and a unique 38-gene panel for deep targeted sequencing of plasma cfDNA was developed. Oncoproteins were measured by enzyme-linked immunosorbent assay, and other variables such as tumor mutational burden and microsatellite instability were evaluated using WES data. Results: The yield of cfDNA was increased 43.6-fold; the integrity of fragments was decreased in GC compared with controls. WES analysis of cancerous tissue and plasma cfDNA (targeted sequencing) mutational profiles revealed 47.8% concordance. The increased quantity of GC tissue–derived alterations detected in cfDNA was associated with worse patients' survival. Analysis of importance of multilayer variables and receiver operating characteristic curve showed that combination of 2 analytes: (i) quantity of tissue matching alterations and (ii) presence of any somatic alteration in plasma cfDNA resulted in area under curve 0.744 when discriminating patients with or without distant metastasis. Furthermore, cfDNA sequence alterations derived from tumor tissue were detected in patients who had even relatively small GC tumors (T1-T2). Discussion: Our results indicate that quantitative and qualitative cfDNA mutational profile analysis is a promising tool for evaluating GC disease status or poorer prognosis.

Hybridisation-based targeted enrichment is a widely used and well-established technique in high-throughput second-generation short-read sequencing. Despite the high potential to genetically resolve highly repetitive and variable genomic sequences by, for example PacBio third-generation sequencing, targeted enrichment for long fragments has not yet established the same high-throughput due to currently existing complex workflows and technological dependencies. We here describe a scalable targeted enrichment protocol for fragment sizes of >7 kb. For demonstration purposes we developed a custom blood group panel of challenging loci. Test results achieved > 65% on-target rate, good coverage (142.7×) and sufficient coverage evenness for both non-paralogous and paralogous targets, and sufficient non-duplicate read counts (83.5%) per sample for a highly multiplexed enrichment pool of 16 samples. We genotyped the blood groups of nine patients employing highly accurate phased assemblies at an allelic resolution that match reference blood group allele calls determined by SNP array and NGS genotyping. Seven Genome-in-a-Bottle reference samples achieved high recall (96%) and precision (99%) rates. Mendelian error rates were 0.04% and 0.13% for the included Ashkenazim and Han Chinese trios, respectively. In summary, we provide a protocol and first example for accurate targeted long-read sequencing that can be used in a high-throughput fashion.