RESUMO
Background: Bacterial infections are associated with the risk of variceal bleeding through complex pathophysiologic pathways. Objectives: The primary objective of the present case-control study was to investigate the role of bacterial translocation and intestinal barrier dysfunction in the pathogenesis of variceal bleeding. A secondary objective was to determine independent predictors of key outcomes in variceal bleeding, including bleeding-related mortality. Methods: Eighty-four (n = 84) consecutive patients participated in the study, 41 patients with acute variceal bleeding and 43 patients with stable cirrhosis, and were followed up for 6 weeks. Peripheral blood samples were collected at patient admission and before any therapeutic intervention. Results: Child-Pugh (CP) score (OR: 1.868; p = 0.044), IgM anti-endotoxin antibody levels (OR: 0.954; p = 0.016) and TGF-ß levels (OR: 0.377; p = 0.026) were found to be significant predictors of variceal bleeding. Regression analysis revealed that albumin (OR: 0.0311; p = 0.023), CRP (OR: 3.234; p = 0.034) and FABP2 levels (OR:1.000, p = 0.040), CP score (OR: 2.504; p = 0.016), CP creatinine score (OR: 2.366; p = 0.008), end-stage liver disease model (MELD), Na (OR: 1.283; p = 0.033), portal vein thrombosis (OR: 0.075; p = 0.008), hepatocellular carcinoma (OR: 0.060; p = 0.003) and encephalopathy (OR: 0.179; p = 0.045) were significantly associated with 6-week mortality. Conclusions: Bacterial translocation and gut barrier impairment are directly related to the risk of variceal bleeding. Microbiota-modulating interventions and anti-endotoxin agents may be promising strategies to prevent variceal bleeding.
RESUMO
The resistance of gram-negative bacteria to most available antibiotics and the lack of new antimicrobial agents have prompted the re-emergence of colistin (CS) as potent treatment against most gram-negative microorganisms. Optimal dosing with CS suffers from poor pharmacokinetic characterization mainly due to the analytical challenge of assaying CS in biological fluids and the limited information on quantitative analysis of CS in plasma using high resolution mass spectrometry (MS). Hence, a rapid, simple and accurate analytical method based on ultra performance liquid chromatography (UPLC) combined with electrospray ionization (ESI) tandem mass spectrometry (MS/MS) on a hybrid quadrupole time of flight (QTOF) instrument has been developed and fully validated for the quantification of CS in human plasma. After the pretreatment of plasma samples by solid phase extraction (SPE) and the addition of the internal standard (reserpine, RSP) the analytes were chromatographed on an Acquity BEH C8 column (100 mm × 2.1 mm, 1.7 µm) using gradient elution with 0.5% aqueous acetic acid (AcOH) and acetonitrile with 0.5% AcOH (with CSA and CSB eluting at 1.39 and 1.31 min, respectively). Accurate mass measurement correction was performed on line using the leukine-enkephaline standard. The method presented good fit (regression coefficient≥0.998) over the quantitation range of 0.2-300 and 0.03-4.5 µg mL(-1) with the lower limit of quantitation (LLOQ) being 0.02 and 0.03 µg mL(-1) for CSA and CSB in human plasma, respectively. The intra- and inter-day precision, measured as %relative standard deviation, was better than 10%, whereas the accuracy expressed as %relative error was also better than 10%. The short term, freeze-thaw (three cycles) and in process stability showed non-significant degradation of CS under these conditions. The validation results showed that the developed method demonstrated adequate selectivity and sensitivity. The method has been successfully applied to plasma samples from patients suffering from cystic fibrosis and treated with CS, and the pharmacokinetic profile has been calculated.