Reduced MPO Activity Research Articles

Pharmacological and Pharmacokinetic Studies with Vitamin D-loaded Nanoemulsions in Asthma Model

Vitamin D (VD) was studied for its anti-inflammatory activities with prepared VD-loaded nanoemulsions (VDNM) in ovalbumin-induced asthmatic mice in this paper. In this study, we prepared VDNM for the delivery of VD from the established composition of solid self-emulsifying drug delivery systems (sSEDDS) by spray-drying technique and evaluated its bioavailability (BA) and anti-inflammatory activities in experimental allergic asthma. After the mice were treated orally with VD or VDNM, the plasma 25(OH) D levels, polymorphonuclear cells, tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), total antioxidant activity, and C3 and C4 complement protein levels were studied, respectively. Treatment with VDNM reduced MPO activity, oxidative stress, C3 protein level, O2(-) level as well as the production of IL-1β and TNF-α. Pharmacokinetic studies showed that a significant increase in the maximum concentration (Cmax) and AUC0→24 h were observed in VDNM group when compared with VD group (P < 0.01). The result revealed that VDNM led to an improvement in oral BA of VD in a murine ovalbumin-induced asthma model. These data provided an important proof that VDNM might be a new potential therapy for the management of asthma in humans.

Potential of Peruviose A and B from Physalis peruviana L calyces to treat Inflammatory Bowel Disease: In vivo and in vitro studies

Phytotherapy constitutes an emerging alternative strategy for the treatment of inflammatory bowel disease (IBD). Although medicinal plants are integral part of Colombian culture, very few of them have been studied deeply.1 One example is Physalis peruviana (Cape gooseberry), which has demonstrated anti-inflammatory activity.2 In this work, we investigated the therapeutic potential of Peruviose A and B; two new sucrose esters recently isolated by us from calyces of P. peruviana, using TNBS-colitis model. For this, ten rats were assigned to groups: control, untreated TNBS-colitis, and treated with a mixture of Peruviose A and B (5 and 10 mg/kg, i.p.) for two weeks. Inflammation was evaluated measuring macroscopic/histologic damage, MPO activity, and cytokine levels. In vitro studies were performed using LPS-stimulated peritoneal macrophages treated with compounds (0.01 – 10 µg/mL). Complementarily, we assessed their effect on E. coli growth. Treatment with Peruviose A/B, at both doses, did not show hepatic or renal injury, while reduced significantly the extent and severity of tissue damage, and colonic weight/length ratio by 58%. In agreement, microscopic disturbances were diminished with reduction of inflammatory cells, distortion of crypts architecture, and necrosis. Compounds also reduced MPO activity (71%), TNF-α (33%) and IL-1β (64%) levels, while IFN-γ and IL-6 were not modified. In vitro assays showed a dose-response inhibition of NO and PGE2 liberation (IC50= 3.9 and 0.07 µg/mL, respectively). Additionally, compounds did not affect E. coli growth, suggesting that the activity is not related with effects on commensal bacteria. Our results provide the first evidence that Peruviose A/B can effectively ameliorate experimental IBD, giving a new application to calyces of P. peruviana, which constitutes a waste in fruit production and an unexplored source of bioactive molecules.

The PepT1-transportable soy tripeptide VPY reduces intestinal inflammation

BackgroundInflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract. The peptide transporter PepT1 is responsible for the intestinal uptake of dietary peptides, and its expression in the gastrointestinal tract is up-regulated during intestinal inflammation, indicating that PepT1 may be a promising target for IBD therapeutics. MethodsThe transport of soy-derived di- and tripeptides across Caco-2 intestinal epithelial cells was examined, and the anti-inflammatory effects of the transported peptide VPY were evaluated in vitro in Caco-2 and THP-1 macrophages, and in vivo in a mouse model of DSS-induced colitis. ResultsVPY inhibited the secretion of IL-8 and TNF-α, respectively, from Caco-2 and THP-1 cells. VPY transport and anti-inflammatory activity in Caco-2 cells was reduced in the presence of Gly-Sar, indicating this activity was mediated by PepT1. In mice, VPY treatment reduced DSS-induced colitis symptoms and weight loss, improved colon histology, reduced MPO activity, and decreased gene expression of the pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFN-γ and IL-17 in the colon. Conclusions and general significanceVPY is a novel PepT1 substrate that can inhibit the production of pro-inflammatory mediators in vitro in intestinal epithelial and immune cells, and reduce the severity of colitis in mice by down-regulating the expression of pro-inflammatory cytokines in the colon, suggesting that VPY may be promising for the treatment of IBD.

Nitric oxide‐mediated augmentation of neutrophil reactive oxygen and nitrogen species formation: Critical use of probes

Previous reports from this laboratory and others demonstrated NO-mediated biphasic modulation of NADPH oxidase and attenuation of neutrophil reactive oxygen species generation, whereas recently we reported augmentation in DCF fluorescence following NO treatment. These discrepancies seem to be due to utilization of different probes/methods to assess effect of NO on reactive oxygen and nitrogen species (ROS/RNS, reactive species) generation. This study aims to look into this and evaluate NO-mediated enzymatic reactive species formation by using multiple probes, human neutrophils/HL60 cells and various interventions. Addition of NO donor, SNP or SNAP (100 nM-1 mM) to PMNs suspension, exhibited a concentration- and time-dependent augmentation in DCF fluorescence, but reduced DHE fluorescence. Collective generation of reactive species was confirmed by enhanced DMPO-nitrone adduct, dityrosine and rhodamine-123 and quenching of scopoletin. NO also enhanced bacterial killing, without altering phagocytosis. Addition of NO to HL-60 cells lacking functional NADPH oxidase enhanced reactive species formation, indicating importance of other enzyme(s) too. NO-dependent ROS/RNS generation was substantially reduced by NADPH oxidase inhibitor (DPI), MPO inhibitor (ABAH), or NOS inhibitor (7-NI). However, 7-NI reduced MPO activity, warranting reappraisal of those reports, which implied NOS in reactive species formation. The results obtained demonstrated NO-mediated reactive species augmentation in human PMNs. Furthermore, superoxide scavenging by NO seems to be the key process in the decrease of DHE fluorescence and suggest usefulness of DCF as the most appropriate probe to measure the NO-mediated modulation of reactive oxygen species in particular in various pathological situations.

CO2 Abdominal Insufflation Decreases Local and Systemic Inflammatory Response in Experimental Acute Pancreatitis

Acute pancreatitis (AP) is a serious disease that is amplified by an associated systemic inflammatory response. We investigated the effect of CO2 pneumoperitoneum on the local and systemic inflammatory response in AP. Acute pancreatitis was induced in Wistar rats by 5% taurocholate intraductal injection. Carbon dioxide pneumoperitoneum was applied for 30 minutes before the induction of AP. Inflammatory parameters were evaluated in the peritoneum (ascites, cell number, and tumor necrosis factor alpha [TNF-alpha]), serum (amylase, TNF-alpha, interleukin-6 [IL-6], and IL-10), pancreas (myeloperoxidase [MPO] activity, cyclo-oxygenase 2 and inducible nitric oxide synthase expression, and histological diagnosis), liver, and lung (mitochondria dysfunction and MPO activity). Abdominal insufflation with CO2 before induction of AP caused a significant decrease in ascites volume, cells, and TNF-alpha in the peritoneal cavity and in serum TNF-alpha and IL-6 but not IL-10 levels. In the pancreas, this treatment reduced MPO activity, acinar and fat necrosis, and the expression of inducible nitric oxide synthase and cyclo-oxygenase 2. There were no significant differences on serum amylase levels, liver mitochondrial function, and pulmonary MPO between groups. Our data demonstrated that CO2 pneumoperitoneum reduced pancreatic inflammation and attenuated systemic inflammatory response in AP. This article suggests that CO2 pneumoperitoneum plays a critical role on the better outcome in patients undergoing laparoscopic pancreatic surgery.

Abstract 978: Novel Endothelial-protective Effect of High Density Lipoprotein: Down-regulation of Toll-like Receptor 4

Introduction: Endothelium-derived Toll-like receptor (TLR) 4 is known to be the key molecule in lipopolysaccharide (LPS)-induced neutrophil sequestration into lungs. The aim of our study was to investigate whether the endothelial-protective effects of HDL also include regulation of Toll-like receptor (TLR) 4. Therefore, we analyzed the effect of HDL supplementation on TLR4 expression in human aortic endothelial cells (HAEC) and the effect of increased HDL following adenoviral apo AI ( Ad.AI) gene transfer (GT) on lung TLR4 expression in an experimental model of LPS-induced endotoxic shock. Methods: HDL (50 μg/ml) was supplemented to HAEC in the presence/absence of LPS (100 ng/ml). Surface-TLR4 expression on HAEC was analyzed by FACS. C57BL/6 mice were i.v. injected with 5 x 10 10 total particles of Ad.AI or with Ad.Null . Fourteen days hereafter, mice were i.p. injected with LPS (80 mg/kg) or with saline and 20 hours afterwards sacrificed. For survival studies, endotoxic shock was induced in 25 mice per group. Lung myeloperoxidase activity (MPO), as a marker of neutrophil infiltration was analysed. Lung TLR4-mRNA expression was determined by real-time PCR, plasma interferon-gamma (INFγ) levels by ELISA. Results: HDL supplementation significantly reduced TLR4 expression on HAEC. Ad.AI resulted in human apo AI expression levels of 80 ± 10 mg/dl at day 14. By 24 hours after LPS injection, 81% of LPS-treated Ad.Null and saline mice died, in contrast to 50% of Ad.AI LPS-treated mice. This was associated with a 1.6- and 1.7-fold (p&lt;0.05) lower lung/body weight ratio in Ad.AI compared to Ad.Null and saline LPS-injected mice. LPS-induced lung TLR4 mRNA expression was 2.0-fold (p&lt;0.05) reduced after human apo AI-GT compared to LPS controls. Moreover, human apo AI-GT significantly reduced neutrophil infiltration in LPS-treated mice, as indicated by 1.8-fold (p&lt;0.05) and 1.9-fold (p&lt;0.05) reduced MPO activity compared to controls, respectively. Plasma INFγ-levels were 2.8-fold and 2.2-fold (p&lt;0.05) lower versus LPS-treated Ad.Null and saline mice, respectively. Conclusion: The HDL-mediated reduction in lung TLR4 expression contributes for the reduced neutrophil infiltration and subsequently may account for improved mortality rate.

Combined treatment with endothelin- and PAF-antagonists reduces posttransplant lung ischemia/reperfusion injury

Background: Pathophysiologic changes of posttransplant lung ischemia/reperfusion injury are mediated by redundant cellular and humoral mechanisms. We investigated the protective effect of combined administration of platelet activating factor (PAF) and endothelin (ET) antagonists after prolonged ischemia in a small animal lung transplantation model. Methods Orthotopic left lung transplantation was performed after 20 hours cold ischemia in male Fischer (F344) rats weighing 200–250 g. Group I served as control. In Group II, donors received 1 mg/kg body weight of the endothelin antagonist TAK-044, and recipients 2 mg/kg. Group III was treated with the PAF antagonist TCV-309 (donor: 50 μg/kg; recipient: 100 μg/kg) (Takeda Chemicals Ltd.). Group IV received a combined treatment with both substances at the same dosage. Twenty-four hours after reperfusion, the native contralateral lung was occluded to assess gas exchange of the graft only, and 5 minutes later the thoracic aorta was punctured for arterial blood gas analysis ( n = 5). In other animals ( n = 5), lung tissue was frozen 24 hours after reperfusion and assessed for myeloperoxidase activity (MPO) and thiobarbituric acid reactive substances. Results Combined inhibition of PAF and ET-1 at the receptor level resulted in significantly improved graft function as compared to controls (Group I), and to groups treated with either TAK-044 or TCV-309. This was determined by a higher arterial oxygen content (112 ± 9 mmHg, p = .00061 vs control, 48 ± 5 mmHg), reduced MPO activity (0.35 ± 0.02 ΔOD/mg/min, p = .000002 vs control, 1.1 ± 0.1 ΔOD/mg/min) and reduced lipid peroxidation (59.5 ± 2.5 pmol/g, p = .011 vs control, 78.5 ± 4.1 pmol/g). The improvement of arterial oxygen (Group II 77 ± 10 mmHg, p = .027 vs control; Group III 84 ± 8 mmHg, p = .0081 vs control) and reduction of MPO activity (Group II 0.85 ± 0.061 ΔOD/mg/min, p = .017; Group III 0.92 ± 0.079 ΔOD/mg/min, p = .058) in groups treated with either a PAF antagonist or an ET antagonist was significantly less than in Group IV. Conclusions Combined donor and recipient treatment with an ET antagonist and a PAF antagonist results in superior posttransplant graft function 24 hours after reperfusion, suggesting a synergistic role of ET-1 and PAF in the mediation of reperfusion injury in this model. Single treatment with either of the antagonists revealed only a slight improvement compared to untreated controls.

Effects of S-ethylisothiourea, a potent inhibitor of nitric oxide synthase, alone or in combination with a nitric oxide donor in splanchnic artery occlusion shock.

1. The aim of this study was to compare the effects of an intravenous infusion of a potent and non selective nitric oxide synthase inhibitor S-ethylisothiourea (Ethyl-TU) with that of a nitric oxide (NO) donor on the pathological sequelae associated with splanchnic artery occlusion (SAO) shock. In addition the effects of the combination of these two treatments were also investigated. 2. SAO shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham operated animals were used as controls. Survival time, white blood cell (WBC) count, mean arterial blood pressure, myeloperoxidase activity (MPO; studied as a quantitative means to evaluate neutrophil accumulation) and the responsiveness of aortic rings to acetylcholine (ACh, 10 nM-10 microM) and to phenylephrine (PE, 1 nM-10 microM) were studied. 3. SAO shocked rats had a decreased survival rate (0% survival 2 h after the release of occlusion) and survival time (76 +/- 10 min), increased MPO activity in the ileum (3.39 +/- 0.8 u x 10(-3) g-1 tissue), a marked leukopenia and a profound hypotension. In addition aortic rings from shocked rats showed a marked hyporeactivity to PE and reduced responsiveness to ACh. Endothelium denuded aortic rings had also a marked hyporeactivity to PE. 4. In vivo administration of Ethyl-TU (0.1 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) significantly increased survival time and rate, improved mean arterial blood pressure, restored the responsiveness to PE, but did not change MPO activity, leukopenia or the impairment in the responsiveness of aortic rings to ACh. Addition of Ethyl-TU (2 microM) to endothelium denuded aortic rings in vitro, restored the marked hyporeactivity to PE. Administration of the NO donor C87-3754 (0.75 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) slightly increased survival time and reduced MPO activity and leukopenia, but did not change survival rate and mean arterial blood pressure. In addition C87-3754 restored the responsiveness of aortic rings to ACh to control values, but did not modify the hyporeactivity to PE. The combination of these two interventions produced a higher degree of protection than either Ethyl-TU or C87-3754 alone. In fact, co-administration of Ethyl-TU plus C87-3754 completely prevented mortality, reduced MPO activity, attenuated leukopenia and the profound hypotension and restored the impaired responsiveness of aortic rings to PE and ACh. 5. Our study suggests that treatment with a nitric oxide synthase inhibitor combined with an NO donor may be a new therapeutic approach to the treatment of splanchnic artery occlusion shock.