miR-138-5p ameliorates intestinal barrier disruption caused by acute superior mesenteric vein thrombosis injury by inhibiting the NLRP3/HMGB1 axis.

Background: Acute superior mesenteric venous thrombosis (ASMVT) decreases junction-associated protein expression and intestinal epithelial cell numbers, leading to intestinal epithelial barrier disruption. Pyroptosis has also recently been found to be one of the important causes of mucosal barrier defects. However, the role and mechanism of pyroptosis in ASMVT are not fully understood. Methods: Differentially expressed microRNAs (miRNAs) in the intestinal tissues of ASMVT mice were detected by transcriptome sequencing (RNA-Seq). Gene expression levels were determined by RNA extraction and reverse transcription-quantitative PCR (RT-qPCR). Western blot and immunofluorescence staining analysis were used to analyze protein expression. H&E staining was used to observe the intestinal tissue structure. Cell Counting Kit-8 (CCK-8) and fluorescein isothiocyanate/propidine iodide (FITC/PI) were used to detect cell viability and apoptosis, respectively. Dual-luciferase reporter assays prove that miR-138-5p targets NLRP3. Results: miR-138-5p expression was downregulated in ASMVT-induced intestinal tissues. Inhibition of miR-138-5p promoted NLRP3-related pyroptosis and destroyed tight junctions between IEC-6 cells, ameliorating ASMVT injury. miR-138-5p targeted to downregulate NLRP3. Knockdown of NLRP3 reversed the inhibition of proliferation, apoptosis, and pyroptosis and the decrease in tight junction proteins caused by suppression of miR-138-5p; however, this effect was later inhibited by overexpressing HMGB1. miR-138-5p inhibited pyroptosis, promoted intestinal epithelial tight junctions and alleviated ASMVT injury-induced intestinal barrier disruption via the NLRP3/HMGB1 axis.

Blood Sampling From Rat Ileal Mesenteric Vein Revealed a Major Role of Dietary Protein in Meal-Induced GLP-1 Response.

The present study was conducted to examine region-dependent glucagon-like peptide-1 (GLP-1) responses to "meal ingestion" under physiological (conscious and unrestrained) conditions using rats with a catheter inserted into either the portal vein (PV) or the ileal mesenteric vein (ILMV). After recovery from the cannulation surgery, blood samples were collected from either PV or ILMV catheter before and after the voluntary ingestion of test diets. After an AIN-93G standard diet ingestion, GLP-1 concentration was higher in ILMV than in PV, and postprandial responses of peptide-YY (PYY) had similar trend, while that of glucose dependent-insulinotropic polypeptide showed an opposite trend to GLP-1/PYY responses. In a separated experiment, a protein-enriched diet containing casein at 25% wt/wt transiently increased GLP-1 concentration only in ILMV; however, a protein-free diet did not increase GLP-1 concentrations in PV or ILMV. These results indicate that postprandial GLP-1 is immediately released from the distal intestine under physiological conditions, and that dietary protein has a critical role in the enhancement of postprandial GLP-1 response.

Calcium Signal Profiles in Vascular Endothelium from Cdh5-GCaMP8 and Cx40-GCaMP2 Mice.

INTRODUCTION: Studies in Cx40-GCaMP2 mice, which express calcium biosensor GCaMP2 in the endothelium under connexin 40 promoter, have identified the unique properties of endothelial calcium signals. However, Cx40-GCaMP2 mouse is associated with a narrow dynamic range and lack of signal in the venous endothelium. Recent studies have proposed many GCaMPs (GCaMP5/6/7/8) with improved properties although their performance in endothelium-specific calcium studies is not known. METHODS: We characterized a newly developed mouse line that constitutively expresses GCaMP8 in the endothelium under the VE-cadherin (Cdh5-GCaMP8) promoter. Calcium signals through endothelial IP3 receptors and TRP vanilloid 4 (TRPV4) ion channels were recorded in mesenteric arteries (MAs) and veins from Cdh5-GCaMP8 and Cx40-GCaMP2 mice. RESULTS: Cdh5-GCaMP8 mice showed lower baseline fluorescence intensity, higher dynamic range, and higher amplitudes of individual calcium signals than Cx40-GCaMP2 mice. Importantly, Cdh5-GCaMP8 mice enabled the first recordings of discrete calcium signals in the intact venous endothelium and revealed striking differences in IP3 receptor and TRPV4 channel calcium signals between MAs and mesenteric veins. CONCLUSION: Our findings suggest that Cdh5-GCaMP8 mice represent significant improvements in dynamic range, sensitivity for low-intensity signals, and the ability to record calcium signals in venous endothelium.

The effect of ivermectin alone and in combination with cobicistat or elacridar in experimental Schistosoma mansoni infection in mice.

Schistosoma mansoni is less susceptible to the antiparasitic drug ivermectin than other helminths. By inhibiting the P-glycoprotein or cytochrome P450 3A in mice host or parasites in a murine model, we aimed at increasing the sensitivity of S. mansoni to the drug and thus preventing infection. We assigned 124 BALB/c mice to no treatment, treatment with ivermectin only or a combination of ivermectin with either cobicistat or elacridar once daily for three days before infecting them with 150 S. mansoni cercariae each. The assignment was done by batches without an explicit randomization code. Toxicity was monitored. At eight weeks post-infection, mice were euthanized. We determined number of eggs in intestine and liver, adult worms in portal and mesenteric veins. Disease was assessed by counting granulomas/cm2 of liver and studying organ weight indices and total weight. IgG levels in serum were also considered. No difference between groups treated with ivermectin only or in combination with cobicistat or elacridar compared with untreated, infected controls. Most mice treated with ivermectin and elacridar suffered severe neurological toxicity. In conclusion, systemic treatment with ivermectin, even in the presence of pharmacological inhibition of P-glycoprotein or cytochrome P450 3A, did not result in effective prophylaxis for S. mansoni infection in an experimental murine model.

Therapeutic potential of flavonoids in the treatment of chronic venous insufficiency.

Chronic venous insufficiency (CVI) is a common disorder associated with a variety of symptoms in later disease stages; despite the high prevalence of this pathology, suitable pharmaceutical therapies have not been explored to date. In this context, it was recently reported that a chronic increase in venous wall stress or biomechanical stretch is sufficient to cause development of varicose veins. Recent evidence demonstrate that flavonoids are natural substances that convey the circulatory system functionality, playing a key role in blood flow. Particularly, troxerutin, diosmin and horse chestnut extract, appear protective for the management of vascular diseases. The aim of the present study was to evaluate the effect of a flavonoid compound, containing troxerutin, diosmin and horse chestnut extract on in vitro model on HUVECs cells, due to its production of vasculoregulatory and vasculotropic molecules, on an ex-vivo model on mesenteric vessel contraction, to regularize mesenteric microcirculation and on in vivo model of CVI-induced by saphene vein ligation. Furthermore, the flavonoid compound capacity of extensibility and compatibility with peripheral veins was investigated through a tissue block culture study. The degree of absorption, the contractile venous activity, the histological analysis, the immunoistochemical and immunofluorescence evaluation for VEGF and CD34 were performed, together with inflammatory mediators dosage. For the first time, this research revealed the therapeutic potential of a compound, enriched with flavonoids, to be a supportive treatment, suitable to reduce varicose vein pathophysiology and to regularize venous tone.

Portomesenteric Venous Thrombosis in Patients Undergoing Surgery for Medically Refractory Ulcerative Colitis.

BACKGROUND: Portomesenteric venous thrombosis (PMVT) is an under-recognized complication of colorectal surgery. The aim of this study was to describe the rate and risk factors for PMVT in patients undergoing surgery for medically refractory ulcerative colitis (UC). METHODS: A retrospective review of medically refractory UC patients who underwent surgery between January 2010 and December 2016 at a single tertiary care center was conducted. PMVT was defined as thrombus within the portal, splenic, superior, or inferior mesenteric vein on postoperative abdominal computed tomography scans. Factors associated with PMVT on univariable analysis were tested in multivariable analysis. Clinical relevance of risk factors was examined with receiver operating characteristic curves and Kaplan-Meier curves. RESULTS: A total of 434 patients were identified. Postoperative venous thromboembolism (VTE) prophylaxis was administered to 428 (98.5%) inpatients for a mean duration of 7.7 ± 0.17 days. PMVT developed in 36 (8.3%) patients a mean interval of 55.3 ± 10.8 days after index surgery. The majority of PMVT occurred after subtotal colectomy, and the most common initial symptom was abdominal pain. Preoperative C-reactive protein (CRP) was associated with PMVT (odds ratio, 1.01; 95% confidence interval, 1.00-1.02; P = 0.01), and the optimal predictive CRP threshold was 45 mg/L. The rate of PMVT development was greater for patients with CRP >45 mg/L (P = 0.01). CONCLUSIONS: PMVT can present as abdominal pain and occur multiple weeks after discharge. Further studies are needed to identify the appropriate postoperative outpatient thrombosis prophylaxis regimen for at-risk patients.

Role of the Renin Angiotensin System in Blood Pressure Allostasis-induced by Severe Food Restriction in Female Fischer rats.

Severe food restriction (FR) is associated with blood pressure (BP) and cardiovascular dysfunction. The renin-angiotensin system (RAS) regulates BP and its dysregulation contributes to impaired cardiovascular function. Female Fischer rats were maintained on a control (CT) or severe FR (40% of CT) diet for 14 days. In response to severe FR, BP allostasis was achieved by up-regulating circulating Ang-[1-8] by 1.3-fold through increased angiotensin converting enzyme (ACE) activity and by increasing the expression of AT1Rs 1.7-fold in mesenteric vessels. Activation of the RAS countered the depressor effect of the severe plasma volume reduction (≥30%). The RAS, however, still underperformed as evidenced by reduced pressor responses to Ang-[1-8] even though AT1Rs were still responsive to the depressor effects of an AT1R antagonist. The aldosterone (ALDO) response was also inadequate as no changes in plasma ALDO were observed after the large fall in plasma volume. These findings have implications for individuals who have experienced a period(s) of severe FR (e.g., anorexia nervosa, dieters, natural disasters) and suggests increased activity of the RAS in order to achieve allostasis contributes to the cardiovascular dysfunction associated with inadequate food intake.

5-HT causes splanchnic venodilation.

Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implanted radiotelemetry transmitters underwent repeated ultrasound imaging of abdominal vessels. After baseline imaging, minipumps containing vehicle (saline) or 5-HT (25 µg·kg-1·min-1) were implanted. Twenty-four hours later, venous diameters were increased in rats with 5-HT-infusion (percent increase from baseline: superior mesenteric vein, 17.5 ± 1.9; portal vein, 17.7 ± 1.8; and abdominal inferior vena cava, 46.9 ± 8.0) while arterial pressure was decreased (~13 mmHg). Measures returned to baseline after infusion termination. In a separate group of animals, treatment with SB-269970 (3 mg/kg iv) prevented the splanchnic venodilation and fall in blood pressure during 24 h of 5-HT infusion. Thus, 5-HT causes 5-HT7 receptor-dependent splanchnic venous dilation associated with a fall in blood pressure.NEW & NOTEWORTHY This research is noteworthy because it combines and links, through the 5-HT7 receptor, an in vitro observation (venorelaxation) with in vivo events (venodilation and fall in blood pressure). This supports the idea that splanchnic venodilation plays a role in blood pressure regulation.

Prostanoids counterbalance the synergism between endothelin-1 and angiotensin II in mesenteric veins of trained rats.

Exercise-induced adaptations of the modulating mechanisms that influence the angiotensin (Ang II) responses assume different features depending on the venous bed. In femoral veins, exercise mobilizes vasodilator prostanoids to cooperate with NO in order to maintain reduced Ang II responses. On the other hand, exercise's influence on the Ang II responses in veins that drain blood from the mesenteric region has been poorly described. Therefore, the present study aimed to identify the effects of a single bout of exercise, as well as exercise training, on the Ang II responses in mesenteric veins. The present study also aimed to investigate the involvement of prostanoids, NO and ET-1 in eventual exercise-induced modifications in these veins. To this end, mesenteric veins taken from resting-sedentary, exercised-sedentary, resting-trained and exercised-trained animals were studied in organ baths. In addition, the mRNA expression of prepro-endothelin-1 (ppET-1), as well as that of the ETA and ETB receptors, were quantified by real-time PCR in these veins. The results show that, either in absence or in presence of L-NAME, the Ang II responses were not different between groups. In the presence of indomethacin, higher Ang II responses were observed in the resting-trained animals than in the resting-sedentary animals. This difference, however, disappeared when L-NAME, BQ-123 or BQ-788 were added during incubation. In addition, no differences in ppET-1, ETA or ETB mRNA expression were observed between groups. Furthermore, in the presence of PD123,319, the Ang II responses in the exercised-sedentary animals were higher than those in the resting-sedentary animals. In conclusion, exercise training mobilizes endothelin-1 (ET-1) to reinforce the Ang II-induced responses mainly through ETA activation. On the other hand, vasodilator prostanoids are mobilized to act in parallel with NO in order to counterbalance the Ang II responses that have been potentiated by ET-1 in these trained animals.

Human splanchnic amino-acid metabolism.

Plasma levels of several amino acids are correlated with metabolic dysregulation in obesity and type 2 diabetes. To increase our understanding of human amino-acid metabolism, we aimed to determine splanchnic interorgan amino-acid handling. Twenty patients planned to undergo a pylorus preserving pancreatico-duodenectomy were included in this study. Blood was sampled from the portal vein, hepatic vein, superior mesenteric vein, inferior mesenteric vein, splenic vein, renal vein, and the radial artery during surgery. The difference between arterial and venous concentrations of 21 amino acids was determined using liquid chromatography as a measure of amino-acid metabolism across a given organ. Whereas glutamine was significantly taken up by the small intestine (121.0 ± 23.8 µmol/L; P < 0.0001), citrulline was released (-36.1 ± 4.6 µmol/L; P < 0.0001). This, however, was not seen for the colon. Interestingly, the liver showed a small, but a significant uptake of citrulline from the circulation (4.8 ± 1.6 µmol/L; P = 0.0138) next to many other amino acids. The kidneys showed a marked release of serine and alanine into the circulation (-58.0 ± 4.4 µmol/L and -61.8 ± 5.2 µmol/L, P < 0.0001), and a smaller, but statistically significant release of tyrosine (-12.0 ± 1.3 µmol/L, P < 0.0001). The spleen only released taurine (-9.6 ± 3.3 µmol/L; P = 0.0078). Simultaneous blood sampling in different veins provides unique qualitative and quantitative information on integrative amino-acid physiology, and reveals that the well-known intestinal glutamine-citrulline pathway appears to be functional in the small intestine but not in the colon.

Neovestitol, an isoflavonoid isolated from Brazilian red propolis, reduces acute and chronic inflammation: involvement of nitric oxide and IL-6.

Isoflavonoids have been largely studied due to their distinct biological activities identified thus far. Herein, we evaluated the activity of neovestitol, an isoflavonoid isolated from Brazilian red propolis, in acute and chronic inflammation. As for acute inflammation, we found that neovestitol reduced neutrophil migration, leukocyte rolling and adhesion, as well as expression of ICAM-1 in the mesenteric microcirculation during lipopolysaccharide-induced acute peritonitis. No changes were observed in the levels of TNF-α, CXCL1/KC and CXCL2/MIP-2 upon pretreatment with neovestitol. The administration of an inducible nitric oxide synthase (iNOS) inhibitor abolished the inhibitory effects of neovestitol in neutrophil migration and ICAM-1 expression. Nitrite levels increased upon treatment with neovestitol. No effects of neovestitol were observed on the chemotaxis of neutrophils in vitro. As for chronic inflammation, neovestitol also reduced the clinical score and joint damage in a collagen-induced arthritis model. There was no change in the frequency of IL-17-producing TCD4+ cells. In addition, pretreatment with neovestitol reduced the levels of IL-6. These results demonstrate a potential anti-inflammatory activity of neovestitol, which may be useful for therapeutic purposes and/or as a nutraceutical.

Salvianolic Acid B Ameliorates Lipopolysaccharide-Induced Albumin Leakage from Rat Mesenteric Venules through Src-Regulated Transcelluar Pathway and Paracellular Pathway.

Lipopolysaccharide (LPS) causes microvascular barrier disruption, leading to albumin leakage from microvessels resulting in a range of disastrous sequels. Salvianolic acid B (SalB) is a major water-soluble component derived from Salvia miltiorrhiza. Previous studies showed its potential to attenuate microvascular barrier dysfunction, but the underlying mechanism is not fully understood. The present study was intended to investigate the impact of SalB on endothelial cell barrier in vivo in rat mesenteric venules as well as in vitro in human umbilical vein endothelial cells (HUVECs), aiming at disclosing the mechanism thereof, particularly the role of Src in its action. Male Wistar rats were challenged by infusion of LPS (2 mg/kg/h) through left femoral vein for 90 min. SalB (5 mg/kg/h) was administrated either simultaneously with LPS or 30 min after LPS infusion through the left jugular vein. Vesicles in venular walls were observed by electron microscopy. HUVECs were incubated with LPS with or without SalB. The expression of Zonula occluden-1 (ZO-1), VE-cadherin, caveolin-1 and Src in HUVECs was assessed by Western blot and confocal microscopy, binding of SalB to Src was measured using Surface Plasmon Resonance and BioLayer Interferometry. Treatment with SalB inhibited albumin leakage from rat mesenteric venules and inhibited the increase of vesicle number in venular endothelial cells induced by LPS. In addition, SalB inhibited the degradation of ZO-1, the phosphorylation and redistribution of VE-cadherin, the expression and phosphorylation of caveolin-1, and phosphoirylation of Src in HUVECs exposed to LPS. Furthermore, SalB was found able to bind to Src. This study demonstrates that protection of SalB against microvascular barrier disruption is a process involving both para- and trans-endothelial cell pathway, and highly suggests Src as the key enzyme for SalB to work.

Testosterone induces leucocyte migration by NADPH oxidase-driven ROS- and COX2-dependent mechanisms.

The mechanisms whereby testosterone increases cardiovascular risk are not clarified. However, oxidative stress and inflammation seem to be determinants. Herein, we sought to determine whether exogenous testosterone, at physiological levels, induces leucocyte migration, a central feature in immune and inflammatory responses and the mediating mechanisms. We hypothesized that testosterone induces leucocyte migration via NADPH oxidase (NADPHox)-driven reactive oxygen species (ROS) and cyclooxygenase (COX)-dependent mechanisms. Sixteen-week-old Wistar rats received an intraperitoneal injection (5 ml) of either testosterone (10(-7) mol/l) or saline. Rats were pre-treated with 5 ml of sodium salicylate (SS, non-selective COX inhibitor, 1.25 × 10(-3) mol/l, 1 h prior to testosterone or saline), flutamide (androgen receptor antagonist, 10(-5) mol/l), apocynin (NADPHox inhibitor, 3 × 10(-4) mol/l), N-[2-Cyclohexyloxy-4-nitrophenyl]methanesulfonamide (NS398, COX2 inhibitor, 10(-4) mol/l) or saline, 4 h before testosterone or saline administration. Leucocyte migration was assessed 24 h after testosterone administration by intravital microscopy of the mesenteric bed. Serum levels of testosterone were measured by radioimmunoassay. NADPHox activity was assessed in membrane fractions of the mesenteric bed by dihydroethidium (DHE) fluorescence and in isolated vascular smooth muscle cells (VSMC) by HPLC. NADPHox subunits and VCAM (vascular cell adhesion molecule) expression were determined by immunoblotting. Testosterone administration did not change serum levels of endogenous testosterone, but increased venular leucocyte migration to the adventia, NADPHox activity and expression (P < 0.05). These effects were blocked by flutamide. SS inhibited testosterone-induced leucocyte migration (P<0.05). Apocynin and NS398 abolished testosterone-induced leucocyte migration and NADPHox activity (P<0.05). Testosterone induces leucocyte migration via NADPHox- and COX2-dependent mechanisms and may contribute to inflammatory processes and oxidative stress in the vasculature potentially increasing cardiovascular risk.

The hydrocortisone protection of glycocalyx on the intestinal capillary endothelium during severe acute pancreatitis.

Malfunctioning of the intestinal microcirculation secondary to severe acute pancreatitis (SAP) can cause injuries to the intestinal mucosal barrier, translocation of gut flora, and sepsis. The glycocalyx on the vascular endothelium helps maintain its normal function through multiple mechanisms, including regulation of vascular permeability and inhibition of intercellular adhesion. It is unknown that whether pancreatitis inflicts injuries to the intestinal mucosal barrier through damaging glycocalyx or stabilizing glycocalyx can be a potential therapeutic target in maintaining the integrity of the intestinal mucosal barrier during SAP. Injecting sodium taurocholate into the pancreatic duct of Sprague-Dawley rats induced SAP. Intestinal perfusion, changes in endothelial glycocalyx, and the associated molecular mechanisms were assessed by laser Doppler velocimetry, electron microscopy, and the levels of heparan sulfate, syndacan-1, and tumor necrosis factor-α (TNF-α) in the superior mesenteric vein. Protective effects of hydrocortisone treatment in the intestinal microcirculation during SAP were evaluated. Degradation of the glycocalyx in intestinal vascular endothelium developed 3 h after the onset of SAP in rats. By 12 h, significant reduction of intestinal perfusion was observed. The concomitant elevated levels of TNF-α in the superior mesenteric vein suggest that TNF-α is involved in the degradation of the glycocalyx. With the use of hydrocortisone, intestinal perfusion was improved and the degradation of glycocalyx was reduced. The degradation of glycocalyx is involved in the malfunction of the intestinal microcirculation. The massive release of TNF-α participates in this process and leads to glycocalyx degradation. Hydrocortisone may be a good therapy to prevent this process.

Isolating and using sections of bovine mesenteric artery and vein as a bioassay to test for vasoactivity in the small intestine.

Mammalian gastrointestinal systems are constantly exposed to compounds (desirable and undesirable) that can have an effect on blood flow to and from that system. Changes in blood flow to the small intestine can result in effects on the absorptive functions of the organ. Particular interest in toxins liberated from feedstuffs through fermentative and digestive processes has developed in ruminants as an area where productive efficiencies could be improved. The video associated with this article describes an in vitro bioassay developed to screen compounds for vasoactivity in isolated cross-sections of bovine mesenteric artery and vein using a multimyograph. Once the blood vessels are mounted and equilibrated in the myograph, the bioassay itself can be used: as a screening tool to evaluate the contractile response or vasoactivity of compounds of interest; determine the presence of receptor types by pharmacologically targeting receptors with specific agonists; determine the role of a receptor with the presence of one or more antagonists; or determine potential interactions of compounds of interest with antagonists. Through all of this, data are collected real-time, tissue collected from a single animal can be exposed to a large number of different experimental treatments (an in vitro advantage), and represents vasculature on either side of the capillary bed to provide an accurate picture of what could be happening in the afferent and efferent blood supply supporting the small intestine.

Maternal 18:3n-3 favors piglet intestinal passage of LPS and promotes intestinal anti-inflammatory response to this bacterial ligand.

We recently observed that maternal 18:3n-3 increases piglet jejunal permeability. We hypothesized that this would favor intestinal lipopolysaccharide (LPS) passage and alter gut immune system education toward this bacterial ligand. Sows were fed 18:3n-3 or 18:2n-6 diets throughout gestation and lactation. In each litter, two piglets were given oral Gram-negative spectrum antibiotic from post-natal day (PND) 14 to 28. All piglets were weaned on a regular diet at PND28. 18:3n-3 piglets exhibited greater jejunal permeability to FITC-LPS at PND28. Levels of 18:3n-3 but neither 20:5n-3 nor 20:4n-6 were greater in mesenteric lymph nodes (MLN) of 18:3n-3 piglets. Jejunal explant or MLN cell cytokine responses to LPS were not influenced by the maternal diet. Antibiotic increased jejunal permeability to FITC-LPS and lowered the level of 20:5n-3 in MLN, irrespective of the maternal diet. At PND52, no long-lasting effect of the maternal diet or antibiotic treatment on jejunal permeability was noticed. 18:3n-3 and 20:4n-6 levels were greater and lower, respectively, in MLN of 18:3n-3 compared to 18:2n-6 piglets. IL-10 production by MLN cells in response to LPS was greater in the 18:3n-3 group, irrespective of the neonatal antibiotic treatment. IL-8 secretion by jejunal explants in response to LPS was lower in antibiotic-treated 18:3n-3 compared to 18:2n-6 piglets. Finally, proportion of MHC class II(+) antigen-presenting cells was greater in 18:3n-3 than 18:2n-6 MLN cells. In conclusion, maternal 18:3n-3 directs the intestinal immune response to LPS toward an anti-inflammatory profile beyond the breastfeeding period; microbiota involvement seems dependent of the immune cells considered.

Effects of acute transmural pressure elevation on endothelium-dependent vasodilation in isolated rat mesenteric veins.

BACKGROUND/AIMS: The vascular regulatory function of the endothelium can be impaired by increases in transmural pressure (TMP). We tested the hypothesis that increasing TMP impairs the endothelial dilator function of rat mesenteric small veins (MSVs). METHODS: In PGF2α-preconstricted MSVs, bradykinin (BK), sodium nitroprusside (SNP) and S-Nitroso-N-acetylpenicillamine (SNAP) concentration-response curves were generated at intermediate (6 mm Hg) and high (12 mm Hg) pressures. BK-induced vasodilation was examined in the absence and presence of nitric oxide synthase inhibitor [N(ω)-nitro-L-arginine (L-NNA), 100 µM], cyclooxygenase inhibitor (indomethacin, 1 µM), and large (BKCa, paxilline, 500 nM) and small (SKCa, apamin, 300 nM) conductance Ca(2+)-activated K(+) channel blockers. RESULTS: BK, SNP and SNAP responses were not altered by TMP increases. BK-induced vasodilation was significantly reduced by L-NNA, indomethacin, apamin and paxilline at 6 mm Hg and L-NNA at 12 mm Hg, and was further reduced by coapplication of apamin and/or paxilline with L-NNA compared with responses obtained with either blocker. Endothelium removal completely abolished BK-induced vasodilation. CONCLUSION: Venous endothelial dilator function is not affected by TMP elevation. BK-induced vasodilation is completely dependent on the presence of functional endothelial cells and mediated in part by nitric oxide, BKCa and SKCa channels, while the participation of prostacyclin may be important at intermediate pressures.

Colitogenic effector T cells: roles of gut-homing integrin, gut antigen specificity and γδ T cells.

Disturbance of T-cell homeostasis could lead to intestinal inflammation. Naive CD4 T cells undergoing spontaneous proliferation, a robust proliferative response that occurs under severe lymphopenic conditions, differentiate into effector cells producing Th1- and/or Th17-type cytokines and induce a chronic inflammation in the intestine that resembles human inflammatory bowel disease. In this study, we investigated the key properties of CD4 T cells necessary to induce experimental colitis. α4ß7 upregulation was primarily induced by mesenteric lymph node (mLN) resident CD11b(+) dendritic cell subsets via transforming growth factor beta (TGFß)/retinoic acid-dependent mechanism. Interestingly, α4ß7 expression was essential but not sufficient to induce inflammation. In addition to gut-homing specificity, expression of gut Ag specificity was also crucial. T-cell acquisition of the specificity was dramatically enhanced by the presence of γδ T cells, a population previously shown to exacerbate T-cell-mediated colitis. Importantly, interleukin (IL)-23-mediated γδ T cell stimulation was necessary to enhance colitogenicity but not gut antigen reactivity of proliferating CD4 T cells. These findings demonstrate that T-cell colitogenicity is achieved through multiple processes, offering a therapeutic rationale by intervening these pathways.

Functional characteristics of alpha adrenergic and endothelinergic receptors in pressurized rat mesenteric veins.

Increasing transmural pressure can alter the functional role of post-junctional receptor subtypes. Under conditions of changing transmural pressure, we investigated the relative contributions of alpha adrenergic (α-ARs) and endothelinergic receptors to norepinephrine (NE) and endothelin (ET-1) contractile responses, respectively, in third-order rat mesenteric small veins (MSV) and arteries (MSA). NE, phenylephrine (PE), clonidine, and ET-1 concentration-response curves were constructed in the absence and presence of α-adrenergic and ET-1 receptor antagonists, respectively. MSV were more sensitive to NE, PE, and ET-1 compared with MSA. The sensitivity of MSV to NE was higher than that to PE. Phentolamine (α1-AR/α2-AR antagonist) and prazosin (α1-AR antagonist) completely abolished NE responses. Yohimbine (α2-AR antagonist) reduced NE and clonidine contractile responses in MSV. Clonidine contractile responses were reduced by prazosin in MSA. In MSA and MSV, BQ-610 (ET(A) receptor antagonist) but not BQ-788 (ET(B) receptor antagonist) reduced ET-1 contractile responses. Combined application of BQ-610 and BQ-788 caused further reduction in ET-1 concentration-response curves obtained in MSV. These results suggest that in addition to α1-ARs and ET(A) receptors, α2-ARs and ET(B) receptors also mediate NE and ET-1 contractile responses in MSV, respectively, with no change in the participation of these receptors as transmural pressure is increased.

Impaired function of prejunctional adenosine A1 receptors expressed by perivascular sympathetic nerves in DOCA-salt hypertensive rats.

Increased sympathetic nervous system activity contributes to deoxycorticosterone acetate (DOCA)-salt hypertension in rats. ATP and norepinephrine (NE) are coreleased from perivascular sympathetic nerves. NE acts at prejunctional α2-adrenergic receptors (α2ARs) to inhibit NE release, and α2AR function is impaired in DOCA-salt rats. Adenosine, an enzymatic ATP degradation product, acts at prejunctional A1 adenosine receptors (A1Rs) to inhibit NE release. We tested the hypothesis that prejunctional A1R function is impaired in sympathetic nerves supplying mesenteric arteries (MAs) and veins (MVs) of DOCA-salt rats. Electrically evoked NE release and constrictions of blood vessels were studied in vitro with use of amperometry to measure NE oxidation currents and video microscopy, respectively. Immunohistochemical methods were used to localize tyrosine hydroxylase (TH) and A1Rs in perivascular sympathetic nerves. TH and A1Rs colocalized to perivascular sympathetic nerves. Adenosine and N(6)-cyclopentyl-adenosine (CPA, A1R agonist) constricted MVs but not MAs. Adenosine and CPA (0.001-10 µM) inhibited neurogenic constrictions and NE release in MAs and MVs. DOCA-salt arteries were resistant to adenosine and CPA-mediated inhibition of NE release and constriction. The A2A adenosine receptor agonist CGS21680 (C23H29N7O6.HCl.xH2O) (0.001-0.1 µM) did not alter NE oxidation currents. We conclude that there are prejunctional A1Rs in arteries and both pre- and postjunctional A1Rs in veins; thus, adenosine selectively constricts the veins. Prejunctional A1R function is impaired in arteries, but not veins, from DOCA-salt rats. Sympathetic autoreceptor dysfunction is not specific to α2ARs, but there is a more general disruption of prejunctional mechanisms controlling sympathetic neurotransmitter release in DOCA-salt hypertension.