The Local Activation of Toll-like Receptor 7 (TLR7) Modulates Colonic Epithelial Barrier Function in Rats.

Toll-like receptors (TLRs)-mediated host-bacterial interactions participate in the microbial regulation of gastrointestinal functions, including the epithelial barrier function (EBF). We evaluated the effects of TLR7 stimulation on the colonic EBF in rats. TLR7 was stimulated with the selective agonist imiquimod (100/300 µg/rat, intracolonic), with or without the intracolonic administration of dimethyl sulfoxide (DMSO). Colonic EBF was assessed in vitro (electrophysiology and permeability to macromolecules, Ussing chamber) and in vivo (passage of macromolecules to blood and urine). Changes in the expression (RT-qPCR) and distribution (immunohistochemistry) of tight junction-related proteins were determined. Expression of proglucagon, precursor of the barrier-enhancer factor glucagon-like peptide 2 (GLP-2) was also assessed (RT-qPCR). Intracolonic imiquimod enhanced the EBF in vitro, reducing the epithelial conductance and the passage of macromolecules, thus indicating a pro-barrier effect of TLR7. However, the combination of TLR7 stimulation and DMSO had a detrimental effect on the EBF, which manifested as an increased passage of macromolecules. DMSO alone had no effect. The modulation of the EBF (imiquimod alone or with DMSO) was not associated with changes in gene expression or the epithelial distribution of the main tight junction-related proteins (occludin, tricellulin, claudin-2, claudin-3, junctional adhesion molecule 1 and Zonula occludens-1). No changes in the proglucagon expression were observed. These results show that TLR7 stimulation leads to the modulation of the colonic EBF, having beneficial or detrimental effects depending upon the state of the epithelium. The underlying mechanisms remain elusive, but seem independent of the modulation of the main tight junction-related proteins or the barrier-enhancer factor GLP-2.

Socio-economic impact of Covid-19 on the fishing sector: A case study of a region highly dependent on fishing in Spain.

Galicia is the most important fishing region in Spain. Nearly 50% of the volume of catches and of the national fishing fleet are concentrated in this region. During the Covid-19 pandemic, the fishing sector had the status of an essential sector and was not forced to stop its activity by the national Government. However, its economic performance has deteriorated in 2020. This article aims to analyze the impact of the pandemic on the extractive fishing sector in Galicia. For this purpose, the performance of the main economic and financial variables of the 246 companies that constitute this industry has been studied. The companies pertain to different extractive sectors (the national, offshore and large-scale fleets) and are in 9 different areas (Vigo, Pontevedra, Arousa, Muros, Fisterra, Costa da Morte, A Coruña-Ferrol, Cedeira and A Mariña). The results of the analysis show that the 9 fishing zones share a generalized negative trend but that there is heterogeneity in the results. Among the most determining factors are the predominant fleet extract, the target species caught, or the perception of public subsidies.

Population pharmacokinetic modelling of rupatadine solution in 6-11 year olds and optimisation of the experimental design in younger children.

AIMS: To optimise a pharmacokinetic (PK) study design of rupatadine for 2-5 year olds by using a population PK model developed with data from a study in 6-11 year olds. The design optimisation was driven by the need to avoid children's discomfort in the study. METHODS: PK data from 6-11 year olds with allergic rhinitis available from a previous study were used to construct a population PK model which we used in simulations to assess the dose to administer in a study in 2-5 year olds. In addition, an optimal design approach was used to determine the most appropriate number of sampling groups, sampling days, total samples and sampling times. RESULTS: A two-compartmental model with first-order absorption and elimination, with clearance dependent on weight adequately described the PK of rupatadine for 6-11 year olds. The dose selected for a trial in 2-5 year olds was 2.5 mg, as it provided a Cmax below the 3 ng/ml threshold. The optimal study design consisted of four groups of children (10 children each), a maximum sampling window of 2 hours in two clinic visits for drawing three samples on day 14 and one on day 28 coinciding with the final examination of the study. CONCLUSIONS: A PK study design was optimised in order to prioritise avoidance of discomfort for enrolled 2-5 year olds by taking only four blood samples from each child and minimising the length of hospital stays.

Population pharmacokinetic modelling of the changes in atazanavir plasma clearance caused by ritonavir plasma concentrations in HIV-1 infected patients.

AIMS: The aim of the present study was to develop a simultaneous population pharmacokinetic model for atazanavir (ATV) incorporating the effect of ritonavir (RTV) on clearance to predict ATV concentrations under different dosing regimens in HIV-1-infected patients. METHODS: A Cross-sectional study was carried out in 83 HIV-1-infected adults taking ATV 400 mg or ATV 300 mg/RTV 100 mg once daily. Demographic and clinical characteristics were registered and blood samples collected to measure drug concentrations. A population pharmacokinetic model was constructed using nonlinear mixed-effects modelling and used to simulate six dosing scenarios. RESULTS: The selected one-compartmental model described the pharmacokinetics of RTV and ATV simultaneously, showing exponential, direct inhibition of ATV clearance according to the RTV plasma concentration, which explained 17.5% of the variability. A mean RTV plasma concentration of 0.63 mg l-1 predicted an 18% decrease in ATV clearance. The percentages of patients with an end-of-dose-interval concentration of ATV below or above the minimum and maximum target concentrations of 0.15 mg l-1 and 0.85 mg l-1 favoured the selection of the simulated ATV/RTV once-daily regimens (ATV 400 mg, ATV 300 mg/RTV 100 mg, ATV 300 mg/RTV 50 mg, ATV 200/RTV 100 mg) over the unboosted twice-daily regimens (ATV 300 mg, ATV 200 mg). CONCLUSIONS: A one-compartment simultaneous model can describe the pharmacokinetics of RTV and ATV, including the effect of RTV plasma concentrations on ATV clearance. This model is promising for predicting individuals' ATV concentrations in clinical scenarios, and supports further clinical trials of once-daily doses of ATV 300 mg/RTV 50 mg or ATV 200 mg/RTV 100 mg to confirm efficacy and safety.

Changes in Epithelial Barrier Function in Response to Parasitic Infection: Implications for IBD Pathogenesis.

BACKGROUND AND AIMS: Mast cells [MCs] are implicated in epithelial barrier alterations that characterize inflammatory and functional bowel disorders. In this study, we describe mast cell proteinases [chymases and tryptases] and tight junction [TJ] proteins kinetics in a rat model of postinfectious gut dysfunction. METHODS: Jejunal tissues of control and -infected rats were used. Inflammation-related changes in MCs and the expression of TJ-related proteins were evaluated by immunostaining and reverse transcription-quantitative polymerase chain reaction. Epithelial barrier function was assessed in vitro (Ussing chambers) and in vivo. RESULTS: After infection, intestinal inflammation was associated with a generalized overexpression of MC chymases, peaking between Days 6 and 14. Thereafter, a mucosal MC hyperplasia and a late increase in connective tissue MC counts were observed. From Day 2 post-infection, TJ proteins occludin and claudin-3 expression was down-regulated whereas the pore-forming protein claudin-2 was overexpressed. The expression of proglucagon, precursor of the barrier-enhancing factor glucagon-like peptide-2, was reduced. These changes were associated with an increase in epithelial permeability, both in vitro and in vivo. CONCLUSIONS: Proteinases expression and location of mucosal and connective tissue MCs indicate a time-related pattern in the maturation of intestinal MCs following infection. Altered expression of TJ-related proteins is consistent with a loss of epithelial tightness, and provides a molecular mechanism for the enhanced epithelial permeability observed in inflammatory conditions of the gut.

Ritonavir boosting dose reduction from 100 to 50 mg does not change the atazanavir steady-state exposure in healthy volunteers.

OBJECTIVES: To evaluate the pharmacokinetics, tolerability and safety of 300 mg of atazanavir boosted with 100 or 50 mg of ritonavir, both once daily, at steady state. METHODS: This was a single-blind, multiple-dose, crossover, sequence-randomized trial. Thirteen healthy HIV-1-negative men received witnessed once-daily doses of atazanavir (300 mg) and 100 or 50 mg of ritonavir for 10 days (15 day washout). Atazanavir and ritonavir plasma concentrations were determined for 24 h on day 10. Log-transformed individual pharmacokinetic parameters were compared between treatments (analysis of variance); the difference between treatments on the log scale and 95% CIs were calculated. Fasting cholesterol, triglycerides, glucose and bilirubin plasma levels were measured at the beginning and end of each period and compared (Wilcoxon signed rank test). Gastrointestinal symptoms and other events were recorded. RESULTS: Ritonavir C(max) and the AUC0₋24 were lower after the 50 mg booster dose than after 100 mg [geometric mean ratio (GMR) (95% CI), 0.40 (0.31-0.51) and 0.35 (0.29-0.42), respectively]. No differences were observed in atazanavir exposure with 50 or 100 mg of ritonavir [GMR C(max) (95% CI), 1.00 (0.79-1.28); GMR AUC0₋24 (95% CI), 0.98 (0.79-1.21)]. Atazanavir trough concentration was >0.15 mg/L in all volunteers. Total and low-density lipoprotein cholesterol increased 0.40 mM (P = 0.01) and 0.37 mM (P = 0.003) from their corresponding baseline value during the 100 mg dosing period; there were no significant changes on 50 mg. Mild increases in bilirubin were detected on day 10 after both treatments without differences between treatments. CONCLUSIONS: In spite of higher exposure to ritonavir with 100 mg, atazanavir exposure was equivalent; the lipid profile was better under the lower booster dose (50 mg).