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In vitro studies showed that 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) increases P-glycoprotein (P-gp) expression and activity in Caco-2 cells, preventing xenobiotic toxicity. The present study aimed at investigating TX5 effects on P-gp expression/activity using Wistar Han rats: a) in vivo, evaluating intestinal P-gp activity; b) ex vivo, evaluating P-gp expression in ileum brush border membranes (BBM) and P-gp activity in everted intestinal sacs; c) ex vivo, evaluating P-gp activity in everted intestinal sacs of the distal and proximal ileum. TX5 (30 mg/kg, b.w.), gavage, activated P-gp in vivo, given the significant decrease in the AUC of digoxin (0.25 mg/kg, b.w.). The efflux of rhodamine 123 (300 μM), a P-gp fluorescent substrate, significantly increased in TX5-treated everted sacs from the distal portion of the rat ileum, when P-gp activity was evaluated in the presence of TX5 (20 μM), an effect abolished by the P-gp inhibitor verapamil (100 μM). No increases on P-gp expression or activity were found in TX5-treated BBM of the distal ileum and everted distal sacs, respectively, 24 h after TX5 (10 mg/kg, b.w.) administration. In vivo, no differences were found on digoxin portal concentration between control (digoxin 0.025 mg/kg, b.w., intraduodenal) and TX5-treated (digoxin+TX5 20 μM, intraduodenal) rats. The observed discrepancies in digoxin results can be related to differences in TX5 dose administered and used methodologies. Thus, the results show that TX5 activates P-gp at the distal portion of the rat ileum, and, at the higher dose tested (30 mg/kg, b.w.), seems to modulate in vivo the AUC of P-gp substrates., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Having established a main neuronal origin for noradrenaline (NA) in the cornea, we set out to study the physiologic determinants of its release and to correlate functional findings with sympathetic nerve density and overall topography. Whole corneas were obtained from 3 to 4 month-old rabbits and human donors. Study of prejunctional effects was carried out after incubation with radiolabelled NA (3H-NA). Corneas were superfused with warm aerated amine-free medium with cocaine and hydrocortisone to block subsequent neuronal and extraneuronal NA uptake. Samples were collected every 5 min. Four periods of transmural electrical stimulation were applied to assess evoked release of 3H-NA in the absence and in the presence of alpha-2 adrenoceptor antagonists. Catecholamines were extracted with alumina from the superfusate collected and quantified by high pressure liquid chromatography with electrochemical detection (HPLC-ED). Corneal nerve morphology was studied by immunofluorescence staining with monoclonal antibodies and subsequent confocal microscopy. Corneal lamellar sections were also produced (epithelium, stroma, endothelium) and endogenous NA and adrenaline (AD) were quantified by HPLC-ED. Results are means ± SEM. ANOVA and t-tests were used for statistical analysis. Ratios between enzymatic end products and their substrates were calculated. In both rabbit and human corneas, electrical stimulation increased the outflow of 3H-NA per minute and per shock. Addition of the alpha-2 adrenoceptor antagonist rauwolscine further increased the electrically-evoked overflow of 3H-NA in a concentration-dependent manner. Immunofluorescence revealed particular staining patterns for sensory and sympathetic fibres, epithelial cells and stromal keratocytes. In human corneal lamellar sections only NA was identified, particularly in the endothelium and epithelium. In the rabbit, concentration of NA was ten times that of AD. Electrically-evoked overflow reflects action potential-induced NA release by sympathetic nerves in the cornea and an alpha-2 adrenoceptor-mediated mechanism for its release is presented. Sympathetic innervation has similar functional relevance in both rabbit and human corneas., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Inflammation is a hallmark of several neurodegenerative disorders including familial amyloidotic polyneuropathy (FAP). FAP is associated with extracellular deposition of mutant transthyretin (TTR), leading to degeneration of cells and tissues, particularly in the peripheral nervous system (PNS). With this work, our goal was to characterize the expression/deposition of TTR and the associated inflammatory immune response, induced by nerve injury, in WT mice and in a mouse model carrying the most common TTR mutation in FAP (V30M). Our results indicate that upon nerve injury TTR is significantly produced by Schwann cells and is dynamically regulated over time in V30M mice, accompanying a peak of inflammation. Strikingly, V30M TTR deposition in nerve tissue occurred, suggesting that inflammation contributes to TTR polymerization. In response to nerve injury, V30M mice display a downregulated innate immune response when compared to WT mice. More specifically, we saw decreased expression of cytokines and chemokines important for the recruitment of immune cells like macrophages and neutrophils, known to be important for the tissue regenerative process which was found impaired in V30M mice. In conclusion, with this work we were able to characterize the biology of TTR both in WT and V30M animals, upon nerve injury, and found that V30M TTR impairs the inflammatory response necessary for nerve regeneration. Taken together, our findings suggest that inflammation is an important target to be considered in therapeutic strategies for FAP., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Degradation of petroleum hydrocarbons in colonized and un-colonized sediments by salt marsh plants Juncus maritimus and Phragmites australis collected in a temperate estuary was investigated during a 5-month greenhouse experiment. The efficiency of two bioremediation treatments namely biostimulation (BS) by the addition of nutrients, and bioaugmentation (BA) by addition of indigenous microorganisms was tested in comparison with hydrocarbon natural attenuation in un-colonized and with rhizoremediation in colonized sediments. Hydrocarbon degrading microorganisms and root biomass were assessed as well as hydrocarbon degradation levels. During the study, hydrocarbon degradation in un-colonized sediments was negligible regardless of treatments. Rhizoremediation proved to be an effective strategy for hydrocarbon removal, yielding high rates in most experiments. However, BS treatments showed a negative effect on the J. maritimus potential for hydrocarbon degradation by decreasing the root system development that lead to lower degradation rates. Although both plants and their associated microorganisms presented a potential for rhizoremediation of petroleum hydrocarbons in contaminated salt marsh sediments, results highlighted that nutrient requirements may be distinct among plant species, which should be accounted for when designing cleanup strategies., (Copyright © 2014 Elsevier Ltd. All rights reserved.)