To measure BT-related markers and proinflammatory cytokines, peripheral blood samples were collected on the same date of pre- and post-treatment HVPG measurements. Blood samples were separated by centrifugation at 1,500×g for 15 minutes within 30 minutes of collection. Samples were stored at −80°C until the analysis.
To determine LPS, serum samples were diluted 1:10 with pyrogen-free water and incubated for 10 minutes at 75°C to remove serum inhibitors. The concentration of LPS in serum was analyzed using the Limulus Amebocyte Lysate (LAL) assay, a quantitative chromogenic test for detecting endotoxins (QCL-1000 LAL assay; Lonza, Walkersville, MD, USA). The lower detection limit for LPS was 0.1 EU/mL. ELISA assays were used to quantitatively measure the serum concentration of LBP (HK315; Hycult Biotech, Uden, The Netherlands), IL-6 (Human Quantikine kits; R&D Systems, Minneapolis, MN, USA), and TNF-α (Human Quantikine kits) according to the manufacturers’ instructions. The absorbance at the 450-nm light wave was measured in each well with a microplate reader (BioTek ELX; BioTek, Shoreline, WA, USA). The lower limit of detection for LBP was 4.4 ng/mL, IL-6 was 0.70 pg/mL, and TNF-α was 0.5 pg/mL. All measurements were performed in duplicate and the mean value is presented.
To determine LPS, serum samples were diluted 1:10 with pyrogen-free water and incubated for 10 minutes at 75°C to remove serum inhibitors. The concentration of LPS in serum was analyzed using the Limulus Amebocyte Lysate (LAL) assay, a quantitative chromogenic test for detecting endotoxins (QCL-1000 LAL assay; Lonza, Walkersville, MD, USA). The lower detection limit for LPS was 0.1 EU/mL. ELISA assays were used to quantitatively measure the serum concentration of LBP (HK315; Hycult Biotech, Uden, The Netherlands), IL-6 (Human Quantikine kits; R&D Systems, Minneapolis, MN, USA), and TNF-α (Human Quantikine kits) according to the manufacturers’ instructions. The absorbance at the 450-nm light wave was measured in each well with a microplate reader (BioTek ELX; BioTek, Shoreline, WA, USA). The lower limit of detection for LBP was 4.4 ng/mL, IL-6 was 0.70 pg/mL, and TNF-α was 0.5 pg/mL. All measurements were performed in duplicate and the mean value is presented.