Induced acute hyperglycemia modifies the barrier function of the intestinal epithelium by tissue inflammation and tight junction disruption resulting in hydroelectrolytic secretion in an animal model.

Diabetic-metabolic syndrome (MetS-D) has a high prevalence worldwide, in which an association with the rupture of the intestinal epithelium barrier function (IEBF) has been pointed out, but the functional and morphological properties are still not well understood. This study aimed to evaluate the impact of acute hyperglycemia diabetes on intestinal tight junction proteins, metabolic failure, intestinal ion and water transports, and IEBF parameters. Diabetes was induced in male Rattus norvegicus (200-310 g) with 0.5 mL of streptozotocin (70 mg/kg). Glycemic and clinical parameters were evaluated every 7 days, and intestinal parameters were evaluated on the 14th day. The MetS-D animals showed a clinical pattern of hyperglycemia, with increases in the area of villi and crypts, lactulose:mannitol ratio, myeloperoxidase (MPO) activity, and intestinal tissue concentrations of malondialdehyde (MDA), but showed a reduction in reduced glutathione (GSH) when these parameters were compared to the control. The MetS-D group had increased secretion of Na+, K+, Cl-, and water compared to the control group in ileal tissue. Furthermore, we observed a reduction in mRNA transcript of claudin-2, claudin-15, and NHE3 and increases of SGLT-1 and ZO-1 in the MetS-D group. These results showed that MetS-D triggered intestinal tissue inflammation, oxidative stress, complex alterations in gene regulatory protein transcriptions of intestinal transporters and tight junctions, damaging the IEBF and causing hydroelectrolyte secretion.

Development of Ti-Al-V alloys for usage as single-axis knee prostheses: evaluation of mechanical, corrosion, and tribocorrosion behaviors.

Single-axis knee prosthesis is an artificial biomechanical device that provides motion to amputees without the need for assistance appliances. Besides it is mainly composed of metallic materials, the current commercial materials did not group adequate properties for long-term usage or accessible cost. This study produced and characterized Ti-(10 -x)Al-xV (x = 0, 2, and 4 wt.%) alloys for potential use as single-axis knee prostheses. The samples exhibited a gradual decrease in the density values, with proper chemical mixing of the alloying elements on the micro-scale. The phase composition exhibited a primary α phase with a minor α' + ß phase for the Ti-8Al-2V and Ti-6Al-4V samples. Due to their different atomic radius compared to Ti, the addition of alloying elements changed the cell parameters. Their selected mechanical properties (Young's modulus, Vickers microhardness, and damping factor) performed better values than the CP-Ti grade 4. The samples also exhibited good corrosion properties against the simulated marine solution. The tribocorrosion resistance of the samples was better than the reference material, with the wear tracks composed of some tribolayers and grooves resulting from adhesive and abrasive wear. The Ti-10Al alloy displayed the best properties and estimated low cost to be used as single-axis knee prostheses.

P2X7 receptor antagonist improves gastrointestinal disorders in spontaneously hypertensive rats.

The purinergic system participates in the control of blood pressure. Hypertension promotes the occurrence of gastrointestinal disorders such as intestinal inflammation and gastric emptying delay. This study aimed i) to investigate the participation of the P2X7 receptor blocker Brilliant Blue G (BBG) on gastric emptying of solids and changes in oxidative stress in the gastric fundus, duodenum, and colon of spontaneously hypertensive rats (SHR) and ii) to study the putative relationship of this effect with the renin-angiotensin system. Rats were divided into five groups: Control, SHR, SHR+BBG, SHR+BBG+ATP, and SHR+BBG+ANG II. In the gastrointestinal tract, we assessed gastric emptying (GE) and oxidative stress markers (NOx, MPO, GSH, SOD). We observed a decrease in the GE rate (P<0.05) in SHR vs control rats (21.8±2.0% vs 42.8±3.5%). The decrease in GE was returned (P<0.05) to control levels by BBG in SHR rats (21.8±2.0% vs 41.6±3.2%). Co-administration of ATP or ANG II together with BBG bypassed the effect of the P2X7 antagonist on GE in SHR (P<0.05) (21.9±5.0% vs 25.6±3.0% vs 41.6±3.2%). The MPO activity increased (P<0.05) in the gastric fundus of SHR compared to control rats (6.12±2.26 vs 0.077±0.02 UMPO/mg tissue); this effect was prevented (P<0.05) by BBG (0.55±0.15 vs 6.12±2.26 UMPO/mg tissue). Data demonstrated that blockage of P2X7 receptors with BBG can improve the GE delay and oxidative stress biomarkers in SHR animals. This preventive effect of BBG on GE delay was abrogated by ANG II and ATP, thus prompting crosstalk between renin-angiotensin and the purinergic signaling systems underlying this phenomenon.

P2X7 receptor antagonist improves gastrointestinal disorders in spontaneously hypertensive rats

The purinergic system participates in the control of blood pressure. Hypertension promotes the occurrence of gastrointestinal disorders such as intestinal inflammation and gastric emptying delay. This study aimed i) to investigate the participation of the P2X7 receptor blocker Brilliant Blue G (BBG) on gastric emptying of solids and changes in oxidative stress in the gastric fundus, duodenum, and colon of spontaneously hypertensive rats (SHR) and ii) to study the putative relationship of this effect with the renin-angiotensin system. Rats were divided into five groups: Control, SHR, SHR+BBG, SHR+BBG+ATP, and SHR+BBG+ANG II. In the gastrointestinal tract, we assessed gastric emptying (GE) and oxidative stress markers (NOx, MPO, GSH, SOD). We observed a decrease in the GE rate (P<0.05) in SHR vs control rats (21.8±2.0% vs 42.8±3.5%). The decrease in GE was returned (P<0.05) to control levels by BBG in SHR rats (21.8±2.0% vs 41.6±3.2%). Co-administration of ATP or ANG II together with BBG bypassed the effect of the P2X7 antagonist on GE in SHR (P<0.05) (21.9±5.0% vs 25.6±3.0% vs 41.6±3.2%). The MPO activity increased (P<0.05) in the gastric fundus of SHR compared to control rats (6.12±2.26 vs 0.077±0.02 UMPO/mg tissue); this effect was prevented (P<0.05) by BBG (0.55±0.15 vs 6.12±2.26 UMPO/mg tissue). Data demonstrated that blockage of P2X7 receptors with BBG can improve the GE delay and oxidative stress biomarkers in SHR animals. This preventive effect of BBG on GE delay was abrogated by ANG II and ATP, thus prompting crosstalk between renin-angiotensin and the purinergic signaling systems underlying this phenomenon.

Antiproliferative, genotoxic and mutagenic potential of synthetic chocolate food flavoring / Potencial antiproliferativo, genotóxico e mutagênico do aroma de chocolate sintético para alimentos

Flavoring additives are of great technological importance for the food industry. However, there is little information regarding the toxicological properties of these micro-ingredients, especially at the cellular level. The present study used meristematic root cells of Allium cepa L. to evaluate the toxicity of a liquid, aroma and flavor synthetic chocolate additive, manufactured and widely marketed throughout Brazil and exported to other countries in South America. The flavoring concentrations evaluated were 100.00; 50.00; 25.00; 1.00; 0.50 and 0.25 µL/L, where the highest concentration established was one-hundred times lower than that commercially suggested for use. The concentration 100 µL/L substantially reduced cell division of meristems within 24- and 48-hours exposure. Concentrations from 100.00 to 0.50 µL/L resulted in a significant number of prophases to the detriment of the other phases of cell division, indicating an aneugenic activity, and induced a significant number of cellular changes, with emphasis on micronuclei, nuclear buds and chromosomal breaks. Under the established analysis conditions, with the exception of concentration 0.25 µL/L, the flavoring of chocolate caused cytotoxicity, genotoxicity and mutagenicity to root meristems.

Os aditivos aromatizantes têm grande importância tecnológica para a indústria de alimentos. Contudo, poucas são as informações quanto as propriedades toxicológicas desses microingredientes, especialmente, em nível celular. No presente estudo avaliou-se, sobre as células meristemáticas de raízes de Allium cepa L., a toxicidade de um aditivo sintético líquido de aroma e sabor de chocolate, fabricado e amplamente comercializado em todo Brasil, e exportado para outros países da América do Sul. As concentrações de aromatizante avaliadas foram 100,00; 50,00; 25,00; 1,00; 0,50 e 0,25 µL/L, onde a maior concentração estabelecida foi cem vezes menor que a sugerida comercialmente para uso. Com base na interpretação dos resultados, a concentração 100 µL/L reduziu substancialmente a divisão celular dos meristemas nas 24 e 48 horas de exposição. As concentrações 100,00 a 0,50 µL/L demonstraram número significativo de prófases em detrimento as outras fases da divisão celular, indicando ação aneugênica, e induziram número significativo de alterações celulares, com ênfase a micronúcleos, broto nucleares e quebras cromossômicas. Nas condições de análises estabelecidas, com exceção a concentração 0,25 µL/L, o aromatizante de chocolate causou citotoxicidade, genotoxicidade e mutagenicidade aos meristemas radiculares.

Antiproliferative, genotoxic and mutagenic potential of synthetic chocolate food flavoring / Potencial antiproliferativo, genotóxico e mutagênico do aroma de chocolate sintético para alimentos

Flavoring additives are of great technological importance for the food industry. However, there is little information regarding the toxicological properties of these micro-ingredients, especially at the cellular level. The present study used meristematic root cells of Allium cepa L. to evaluate the toxicity of a liquid, aroma and flavor synthetic chocolate additive, manufactured and widely marketed throughout Brazil and exported to other countries in South America. The flavoring concentrations evaluated were 100.00; 50.00; 25.00; 1.00; 0.50 and 0.25 µL/L, where the highest concentration established was one-hundred times lower than that commercially suggested for use. The concentration 100 µL/L substantially reduced cell division of meristems within 24- and 48-hours exposure. Concentrations from 100.00 to 0.50 µL/L resulted in a significant number of prophases to the detriment of the other phases of cell division, indicating an aneugenic activity, and induced a significant number of cellular changes, with emphasis on micronuclei, nuclear buds and chromosomal breaks. Under the established analysis conditions, with the exception of concentration 0.25 µL/L, the flavoring of chocolate caused cytotoxicity, genotoxicity and mutagenicity to root meristems.

Os aditivos aromatizantes têm grande importância tecnológica para a indústria de alimentos. Contudo, poucas são as informações quanto as propriedades toxicológicas desses microingredientes, especialmente, em nível celular. No presente estudo avaliou-se, sobre as células meristemáticas de raízes de Allium cepa L., a toxicidade de um aditivo sintético líquido de aroma e sabor de chocolate, fabricado e amplamente comercializado em todo Brasil, e exportado para outros países da América do Sul. As concentrações de aromatizante avaliadas foram 100,00; 50,00; 25,00; 1,00; 0,50 e 0,25 µL/L, onde a maior concentração estabelecida foi cem vezes menor que a sugerida comercialmente para uso. Com base na interpretação dos resultados, a concentração 100 µL/L reduziu substancialmente a divisão celular dos meristemas nas 24 e 48 horas de exposição. As concentrações 100,00 a 0,50 µL/L demonstraram número significativo de prófases em detrimento as outras fases da divisão celular, indicando ação aneugênica, e induziram número significativo de alterações celulares, com ênfase a micronúcleos, broto nucleares e quebras cromossômicas. Nas condições de análises estabelecidas, com exceção a concentração 0,25 µL/L, o aromatizante de chocolate causou citotoxicidade, genotoxicidade e mutagenicidade aos meristemas radiculares.

Antiproliferative, genotoxic and mutagenic potential of synthetic chocolate food flavoring

Abstract Flavoring additives are of great technological importance for the food industry. However, there is little information regarding the toxicological properties of these micro-ingredients, especially at the cellular level. The present study used meristematic root cells of Allium cepa L. to evaluate the toxicity of a liquid, aroma and flavor synthetic chocolate additive, manufactured and widely marketed throughout Brazil and exported to other countries in South America. The flavoring concentrations evaluated were 100.00; 50.00; 25.00; 1.00; 0.50 and 0.25 µL/L, where the highest concentration established was one-hundred times lower than that commercially suggested for use. The concentration 100 µL/L substantially reduced cell division of meristems within 24- and 48-hours exposure. Concentrations from 100.00 to 0.50 µL/L resulted in a significant number of prophases to the detriment of the other phases of cell division, indicating an aneugenic activity, and induced a significant number of cellular changes, with emphasis on micronuclei, nuclear buds and chromosomal breaks. Under the established analysis conditions, with the exception of concentration 0.25 µL/L, the flavoring of chocolate caused cytotoxicity, genotoxicity and mutagenicity to root meristems.

Resumo Os aditivos aromatizantes têm grande importância tecnológica para a indústria de alimentos. Contudo, poucas são as informações quanto as propriedades toxicológicas desses microingredientes, especialmente, em nível celular. No presente estudo avaliou-se, sobre as células meristemáticas de raízes de Allium cepa L., a toxicidade de um aditivo sintético líquido de aroma e sabor de chocolate, fabricado e amplamente comercializado em todo Brasil, e exportado para outros países da América do Sul. As concentrações de aromatizante avaliadas foram 100,00; 50,00; 25,00; 1,00; 0,50 e 0,25 µL/L, onde a maior concentração estabelecida foi cem vezes menor que a sugerida comercialmente para uso. Com base na interpretação dos resultados, a concentração 100 µL/L reduziu substancialmente a divisão celular dos meristemas nas 24 e 48 horas de exposição. As concentrações 100,00 a 0,50 µL/L demonstraram número significativo de prófases em detrimento as outras fases da divisão celular, indicando ação aneugênica, e induziram número significativo de alterações celulares, com ênfase a micronúcleos, broto nucleares e quebras cromossômicas. Nas condições de análises estabelecidas, com exceção a concentração 0,25 µL/L, o aromatizante de chocolate causou citotoxicidade, genotoxicidade e mutagenicidade aos meristemas radiculares.

Antiproliferative, genotoxic and mutagenic potential of synthetic chocolate food flavoring.

Flavoring additives are of great technological importance for the food industry. However, there is little information regarding the toxicological properties of these micro-ingredients, especially at the cellular level. The present study used meristematic root cells of Allium cepa L. to evaluate the toxicity of a liquid, aroma and flavor synthetic chocolate additive, manufactured and widely marketed throughout Brazil and exported to other countries in South America. The flavoring concentrations evaluated were 100.00; 50.00; 25.00; 1.00; 0.50 and 0.25 µL/L, where the highest concentration established was one-hundred times lower than that commercially suggested for use. The concentration 100 µL/L substantially reduced cell division of meristems within 24- and 48-hours exposure. Concentrations from 100.00 to 0.50 µL/L resulted in a significant number of prophases to the detriment of the other phases of cell division, indicating an aneugenic activity, and induced a significant number of cellular changes, with emphasis on micronuclei, nuclear buds and chromosomal breaks. Under the established analysis conditions, with the exception of concentration 0.25 µL/L, the flavoring of chocolate caused cytotoxicity, genotoxicity and mutagenicity to root meristems.

A baseline evaluation of PAH body burden in sardines from the southern Brazilian shelf.

The concentrations of 37 polycyclic aromatic hydrocarbons (PAHs) and their potential risk to human health were determined in fifty sardine muscle (Sardinella brasiliensis) samples collected along the southern Brazilian shelf. Parental and alkylated PAHs were identified and quantified using a pressurized liquid extraction with in-cell purification method and gas chromatography-mass spectrometry identification and quantification. The concentrations of Σ37 PAHs in muscle ranged between 6.02 and 4074 µg kg-1 wet weight, which are comparable to levels reported for commercially important fish worldwide. The most abundant compounds were pyrene and fluoranthene, which originate from both petrogenic and pyrolytic hydrocarbon inputs. In only 4% of the samples the benzo[a] pyrene equivalent concentration was above the threshold of 6 µg kg-1 suggested for safe fish consumption in Brazil. These findings will serve as baseline data for monitoring the quality of sardines consumed in the country and for studying fish populations.

Alanyl-glutamine protects the intestinal barrier function in trained rats against the impact of acute exhaustive exercise.

Strenuous exercise triggers deleterious effects on the intestinal epithelium, but their mechanisms are still uncertain. Here, we investigated whether a prolonged training and an additional exhaustive training protocol alter intestinal permeability and the putative effect of alanyl-glutamine (AG) pretreatment in this condition. Rats were allocated into 5 different groups: 1) sedentary; 2 and 3) trained (50 min per day, 5 days per week for 12 weeks) with or without 6 weeks oral (1.5 g/kg) AG supplementation; 4 and 5) trained and subjected to an additional exhaustive test protocol with or without oral AG supplementation. Venous blood samples were collected to determine gasometrical indices at the end of the 12-week protocol or after exhaustive test. Lactate and glucose levels were determined before, during, and after the exhaustive test. Ileum tissue collected after all experimental procedures was used for gene expression analysis of Zonula occludens 1 (ZO-1), occludin, claudin-2, and oligopeptide transporter 1 (PepT-1). Intestinal permeability was assessed by urinary lactulose/mannitol test collected after the 12-week protocol or the exhaustive test. The exhaustive test decreased pH and base excess and increased pCO2. Training sessions delayed exhaustion time and reduced the changes in blood glucose and lactate levels. Trained rats exhibited upregulation of PEPT-1, ZO-1, and occludin mRNA, which were partially protected by AG. Exhaustive exercise induced intestinal paracellular leakage associated with the upregulation of claudin-2, a phenomenon protected by AG treatment. Thus, AG partially prevented intestinal training adaptations but also blocked paracellular leakage during exhaustive exercise involving claudin-2 and occludin gene expression.

Alanyl-glutamine protects the intestinal barrier function in trained rats against the impact of acute exhaustive exercise

Strenuous exercise triggers deleterious effects on the intestinal epithelium, but their mechanisms are still uncertain. Here, we investigated whether a prolonged training and an additional exhaustive training protocol alter intestinal permeability and the putative effect of alanyl-glutamine (AG) pretreatment in this condition. Rats were allocated into 5 different groups: 1) sedentary; 2 and 3) trained (50 min per day, 5 days per week for 12 weeks) with or without 6 weeks oral (1.5 g/kg) AG supplementation; 4 and 5) trained and subjected to an additional exhaustive test protocol with or without oral AG supplementation. Venous blood samples were collected to determine gasometrical indices at the end of the 12-week protocol or after exhaustive test. Lactate and glucose levels were determined before, during, and after the exhaustive test. Ileum tissue collected after all experimental procedures was used for gene expression analysis of Zonula occludens 1 (ZO-1), occludin, claudin-2, and oligopeptide transporter 1 (PepT-1). Intestinal permeability was assessed by urinary lactulose/mannitol test collected after the 12-week protocol or the exhaustive test. The exhaustive test decreased pH and base excess and increased pCO2. Training sessions delayed exhaustion time and reduced the changes in blood glucose and lactate levels. Trained rats exhibited upregulation of PEPT-1, ZO-1, and occludin mRNA, which were partially protected by AG. Exhaustive exercise induced intestinal paracellular leakage associated with the upregulation of claudin-2, a phenomenon protected by AG treatment. Thus, AG partially prevented intestinal training adaptations but also blocked paracellular leakage during exhaustive exercise involving claudin-2 and occludin gene expression.

Preoperative biliary drainage in patients performing pancreaticoduodenectomy : guidelines and real-life practice.

BACKGROUND AND AIM: Preoperative biliary drainage (PBD) in patients with pancreatic cancer remains debatable. The aim of this study was to analyse the indications for PBD in patients performing pancreaticoduodenectomy (PD) and to evaluate the impact of this procedure on postoperative outcome. METHODS: Observational retrospective cohort study of patients undergoing PD for pancreatic cancer. Clinical data and postoperative outcome, namely complications and 90-day mortality, were prospectively collected and compared between patients performing PBD or direct surgery (DS). RESULTS: Eighty-two patients were included: 40 underwent PBD and 42 performed DS. Major complications (27.5% vs 33.3%, P=0.156) and 90-day mortality (10% vs 16.7%, P=0.376) were similar between the two groups. There was a trend for higher mean total bilirubin in patients with PBD (P=0.073). The indication for PBD was suspicion of cholangitis/choledocholithiasis or need to perform neoadjuvant chemotherapy in 24 (60%) patients. In the remaining, elevated bilirubin was probably the only reason to perform PBD. Length of hospital stay was longer in PBD group (P=0.003). On multiple logistic regression, 90-day mortality was not related with preoperative bilirubin levels, biliary drainage or its indication, but solely with age (OR 1.15, 95%CI 1.05-1.31, P=0.008). CONCLUSIONS: PBD is often performed in patients undergoing PD without a formal indication, mainly due to high bilirubin levels. No increased morbidity/mortality was observed but length of hospital stay was prolonged in patients performing PBD.

Short-term wind speed forecasting in Uruguay using computational intelligence.

Short-term wind speed forecasting for Colonia Eulacio, Soriano Department, Uruguay, is performed by applying an artificial neural network (ANN) technique to the hourly time series representative of the site. To train the ANN and validate the technique, data for one year are collected by one tower, with anemometers installed at heights of 101.8, 81.8, 25.7, and 10.0 m. Different ANN configurations are applied for each site and height; then, a quantitative analysis is conducted, and the statistical results are evaluated to select the configuration that best predicts the real data. This method has lower computational costs than other techniques, such as numerical modelling. For integrating wind power into existing grid systems, accurate short-term wind speed forecasting is fundamental. Therefore, the proposed short-term wind speed forecasting method is an important scientific contribution for reliable large-scale wind power forecasting and integration in Uruguay. The results of the short-term wind speed forecasting showed good accuracy at all the anemometer heights tested, suggesting that the method is a powerful tool that can help the Administración Nacional de Usinas y Transmissiones Eléctricas manage the national energy supply.

Acute Toxicity and Sub-lethal Effects of the Essential Oil of Aristolochia trilobata and Its Major Constituents on Nasutitermes corniger (Termitidae: Nasutitermitinae).

Nasutitermes corniger (Motschulsky, 1855) (Termitidae: Nasutitermitinae) is an important pest in urban environments and bioinsecticides can be an alternative to its control. Here, we determined the toxicity and repellence of the essential oil (EO) prepared from stems of Aristolochia trilobata L. (Aristolochiaceae) and its major constituents on N. corniger. We also investigated behavioral changes of individuals exposed to limonene. The lethal dose required to kill 50% of N. corniger population (LD50) of EO of A. trilobata was 2.44 µg mg-1. Limonene was the most toxic compound to N. corniger followed by linalool (LD50 = 1.02 and 1.29 µg mg-1, respectively). In addition, all treatments presented median lethal time (LT50) less than 11 h. A. trilobata EO and its constituents showed irritability activity, but only limonene repelled soldiers more than workers. The negative behaviors of N. corniger groups were higher in individuals treated with limonene. A. trilobata EO and its constituents, especially the limonene, are promising for the control of N. corniger due the high toxicity, repellence, and possible disturbance in the colonies.

Acute exercise inhibits gastric emptying of liquids in rats: influence of the NO-cGMP pathway.

We previously found that acute exercise inhibited the gastric emptying of liquid in awake rats by causing an acid-base imbalance. In the present study, we investigated the involvement of the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, vasoactive intestinal peptide (VIP), and corticotropin-releasing factor (CRF) peptide in this phenomenon. Male rats were divided into exercise or sedentary group and were subjected to a 15-min swim session against a load (2.5 or 5% b.w.). The rate of gastric emptying was evaluated after 5, 10, or 20 min postprandially. Separate groups of rats were treated with vehicle (0.9% NaCl, 0.1 mL/100 g, ip) or one of the following agents: atropine (1.0 mg/kg, ip), the NO non-selective inhibitor Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME; 10.0 mg/kg, ip), or the selective cGMP inhibitor 1H-(1,2,4)oxadiazole[4,3-a]quinoxalin-1-one (ODQ; 5.0 mg/kg, ip), the i-NOS non-specific inhibitor (aminoguanidine; 10.0 mg/kg, ip), the corticotropin-releasing factor receptor antagonist (astressin; 100 µg/kg, ip), or the vasoactive intestinal peptide (VIP) receptor antagonist Lys1, Pro2,5, Arg3,4, Tyr6 (100 µg/kg, ip). Compared to sedentary rats, both the 2.5 and 5% exercise groups exhibited higher (P<0.05) values of blood lactate and fractional gastric dye recovery. Corticosterone and NO levels increased (P<0.05) in the 5% exercised rats. Pretreatment with astressin, VIP antagonist, atropine, L-NAME, and ODQ prevented the increase in gastric retention caused by exercise in rats. Acute exercise increased gastric retention, a phenomenon that appears to be mediated by the NO-cGMP pathway, CRF, and VIP receptors.

Role of TRPV1 receptor in inflammation and impairment of esophageal mucosal integrity in a murine model of nonerosive reflux disease.

BACKGROUND: Microscopic inflammation and impairment of the esophageal epithelial barrier are considered relevant for perception of symptoms in patients with nonerosive reflux disease (NERD). In these patients, the receptor transient receptor potential vanilloid 1 (TRPV1) is overexpressed in the esophageal mucosa, but its role is not yet fully understood. We evaluated the role of TRPV1 in esophageal inflammation and mucosal barrier impairment in a murine model of NERD. METHODS: Nonerosive reflux disease was surgically induced in Swiss mice by pyloric substenosis and ligature of the gastric fundus, and the mice were killed 7 days post surgery. The experimental groups were: I, sham surgery (negative control); II, NERD untreated; III and IV, NERD + SB366791 or capsazepine (TRPV1 antagonists); and V, NERD + resiniferatoxin (for long-term desensitization of TRPV1). The esophagus was collected for western blotting and histopathology and for evaluation of wet weight, myeloperoxidase (MPO), keratinocyte-derived chemokine (KC), transepithelial electrical resistance (TEER), and basal permeability to fluorescein. KEY RESULTS: Compared to sham, NERD mice had increased esophageal wet weight and MPO and KC levels. The mucosa had no ulcers but exhibited inflammation. NERD mice showed mucosal TRPV1 overexpression, a more pronounced decrease in TEER at pH 0.5 (containing pepsin and taurodeoxycholic acid), and increased basal permeability. Pharmacological modulation of TRPV1 prevented esophageal inflammation development, TEER changes by acidic exposure, and increase in esophageal permeability. CONCLUSIONS & INFERENCES: The TRPV1 receptor has a critical role in esophageal inflammation and mucosal barrier impairment in NERD mice, suggesting that TRPV1 might be a pharmacological target in patients with NERD.