Nitric oxide in inflammation and immune response

Self-Assembled Peptide-Based Fibrous Hydrogel as a Biological Catalytic Scaffold for Nitric Oxide Generation and Encapsulation

Biomolecular hydrogels are promising scaffolds for biomedical applications ranging from controlled drug release to personalized medicine. However, existing macromolecular scaffolds for nitric oxide (NO) release face several challenges, such as a low payload capacity, rapid release, and limited biocompatibility. Here, we present the design of short peptide derivatives as low-molecular-weight gelators that spontaneously self-assemble into nanofibrous hydrogels under basic aqueous conditions. Hydrogen bonding and hydrophobic interactions are central driving forces for the assembly process and contribute to tuning the mechanical properties. The nanofibrous hydrogel exhibits secondary structure properties, and the nanofibers show crystalline behavior. The terminal primary amines in the peptide building blocks could act as nucleophiles, facilitating the endogenous generation of NO gas, thus making the hydrogel scaffold a catalyst. The nanofibrous hydrogels can sequester NO from an external source that could be trapped in the interstices of the entangled fibrous networks. Simultaneously, it demonstrates anti-inflammatory effects in activated murine macrophages. This designer peptide hydrogel for NO generation and encapsulation provides fundamental insights into the design of peptide biomaterials for biomedical applications.

Exploring processing-structure-property relationships of chemically precipitated strontium silicate particles for medical applications

Bone regeneration in the presence of osteoporosis presents a significant challenge in dental and orthopedic surgery. To tackle this issue, researchers have developed strontium-containing biomaterials. However, preventing bacterial infection is also crucial for successful surgical treatment. In this study, we delved deep into the processing to tailor the composition and structure of new strontium silicates with unique properties to address this challenge. We used chemical precipitation to prepare various strontium silicate particles using varying ammonia concentrations and Sr/Si precursor ratios. The L929 cytotoxicity, differentiation of human mesenchymal stem cells (hMSCs), biological function of RAW 264.7 macrophages, and antibacterial activity against E. coli and S. aureus were evaluated. As a result, higher ammonia concentration led to the formation of SrSiO3 and Sr2SiO4 particles with smaller sizes and higher Sr/Si ratios. These particles exhibited increased antibacterial efficacy and radiopacity, promoting cell viability and osteogenic activity of hMSCs and modulating M1/M2 macrophage polarization. In conclusion, the developed strontium silicate demonstrated superior antibacterial activity, exceptional osteogenic properties, and clear visibility during procedures, making it a promising material for bone regeneration and osteoporosis treatment.

Sleep recovery ameliorates submandibular salivary gland inflammation associated with paradoxical sleep deprivation in male Wistar rats

OBJECTIVE

Submandibular salivary gland inflammation has been suggested as one of the mechanisms underlying impaired salivary secretion associated with sleep deprivation (SD). However, whether the salivary inflammatory response occurs to the same extent in paradoxical sleep deprivation with or without sleep recovery remains unknown. This study evaluated the extent to which inflammation influences salivary impairments associated with paradoxical sleep deprivation with or without sleep recovery.

METHODOLOGY

Male Wistar rats were randomly assigned into three groups as control, partial SD (PSD) with sleep recovery for four hours a day and total SD (TSD). Paradoxical SD was carried out for seven days in the SD groups, after which saliva, blood, and submandibular gland samples were taken. Levels of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), and nitrite were determined in saliva, serum, and the submandibular salivary gland. Leucocyte count and neutrophil-lymphocyte ratio were determined in all groups. One-way ANOVA and the Tukey's post hoc tests were used for data analysis. P-values < 0.05 were considered statistically significant.

RESULTS

Levels of TNF-α, IL-6, and nitrite in the submandibular salivary glands were significantly higher in the TSD groups (p=0.04,p<0.001, p=0.03, respectively) than in the control. Saliva level of TNF-α was higher in the PSD and TSD groups (p=0.003 and p=0.01 respectively) than in the control. Neutrophil-lymphocyte ratio was significantly higher in both PSD and TSD groups than in the control (p<0.01 for both).

CONCLUSION

While total SD produced higher inflammatory response in the submandibular salivary gland, four-hour sleep recovery ameliorated this impact. This finding suggests that sleep recovery is crucial to improve inflammatory salivary gland dysfunction induced by sleep deprivation.

In vitro and In vivo Activity of a New N-Oxide Derivative for Acne Vulgaris Treatment

INTRODUCTION

Furoxan and benzofuroxan are compounds containing an N-oxide function, known for their diverse pharmacological properties, including antimicrobial and antiinflammatory effects. This study aimed to investigate these activities using an in-house library of N-oxide compounds.

METHOD

Twenty compounds were tested against both Gram-positive and Gram-negative bacteria, including Cutibacterium acnes (C. acnes), a microorganism implicated in the development of acne vulgaris. One compound, (E)-4-(3-((2-(3-hydroxybenzoyl)hydrazone)methyl)phenoxy)-3- (phenylsulfonyl)-1,2,5-oxadiazol-2-N-oxide (compound 15), exhibited selective antimicrobial activity against C. acnes, with a Minimum Inhibitory Concentration (MIC) value of 2 μg/mL. Indirect measurement of Nitric Oxide (NO) release showed that compound 15 and isosorbide dinitrate, when treated with L-cysteine, produced nitrite levels of 20.1% and 9.95%, respectively. Using a NO scavenger (PTIO) in combination with compound 15 in a culture of C. acnes resulted in reduced antimicrobial activity, indicating that NO release is part of its mechanism of action. Cytotoxicity assessments using murine macrophages showed cellular viability above 70% at concentrations up to 0.78 μg/mL.

RESULTS

Measurements of Interleukin-1 beta (IL1-β) and Tumor Necrosis Factor-alpha (TNF-α) indicated that compound 15 did not reduce the levels of these pro-inflammatory cytokines. Sustained NO production by inducible Nitric Oxide Synthase (iNOS) in macrophages or neutrophils has been found to be involved in the inflammatory process in acne vulgaris and lead to toxicity in surrounding tissues. Nitrite levels in the supernatant of murine macrophages were found to be decreased at a concentration of 0.78 μg/mL of compound 15, indicating an anti-inflammatory effect. In vivo studies were conducted using Balb/c nude mice inoculated subcutaneously with C. acnes. Cream and gel formulations of compound 15 were applied to treat the animals, along with commercially available anti-acne drugs, for 14 days. Animals treated with a cream base containing 5% of compound 15 exhibited less acanthosis with mild inflammatory infiltration compared to other groups, highlighting its anti-inflammatory properties.

CONCLUSION

Similar results were observed in the benzoyl peroxide group, demonstrating that compound 15 presented comparable anti-inflammatory activity to the FDA-approved drug. These promising results suggest that compound 15 has a dual mechanism of action, with selective antimicrobial activity against C. acnes and notable anti-inflammatory properties, making it a potential prototype for developing new treatments for acne vulgaris.

Stimuli-Responsive NO Delivery Platforms for Bacterial Infection Treatment

The prevalence of drug-resistant bacterial infections has emerged as a grave threat to clinical treatment and global human health, presenting one of the foremost challenges in medical care. Thus, there is an urgent imperative to develop safe and efficacious novel antimicrobial strategies. Nitric oxide (NO) is a recognized endogenous signaling molecule, which plays a pivotal role in numerous pathological processes. Currently, NO has garnered significant interest as an antibacterial agent due to its capability to eradicate bacteria, disrupt biofilms, and facilitate wound healing, all while circumventing the emergence of drug resistance. However, the inherently unstable characteristic of NO therapeutic gas renders the controlled administration of NO gases exceedingly challenging. Hence, in this review, the current challenge of bacterial infection is discussed; then it is briefly elucidated the antibacterial mechanism of NO and comprehensively delineate the recent advancements in stimulus-responsive NO delivery platforms, along with their merits, obstacles, and prospective avenues for clinical application. This review offers guidance for future advancements in NO-medicated anti-infection therapy is hoped.

The Role of Neuro-Immune Interactions in the Pathology and Pathogenesis of Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is a non-infectious inflammatory disease of the nasal mucosa mediated by IgE and involving a variety of immune cells such as mast cells. In previous studies, AR was considered as an isolated disease of the immune system. However, recent studies have found that the nervous system is closely related to the development of AR. Bidirectional communication between the nervous and immune systems plays an important role in AR.

SUMMARY

The nervous system and immune system depend on the anatomical relationship between nerve fibers and immune cells, as well as various neurotransmitters, cytokines, inflammatory mediators, etc. to produce bidirectional connections, which affect the development of AR.

KEY MESSAGES

This article reviews the impact of neuro-immune interactions in AR on the development of AR, including neuro-immune cell units.

Triplinones A-H: Anti-Inflammatory Arylalkenyl α,β-Unsaturated-δ-Lactones Isolated from the Leaves of Australian Rainforest Plant Cryptocarya triplinervis (Lauraceae)

Our ongoing exploration of Australian rainforest plants for the biodiscovery of anti-inflammatory agents led to the isolation and structural elucidation of eight new arylalkenyl α,β-unsaturated-δ-lactones, triplinones A-H (1-8), from the leaves of the Australian rainforest plant Cryptocarya triplinervis B. Hyland (Lauraceae). The chemical structures of these compounds were established by NMR spectroscopic data analysis, while their relative and absolute configurations were established using a combination of Mosher ester analysis utilizing both Riguera's and Kishi's methods, ECD experiments, and X-ray crystallography analysis. Compounds 1-8 exhibited good inhibitory activities toward nitric oxide (NO) production in lipopolysaccharide (LPS) and interferon (IFN)-γ induced RAW 264.7 macrophages, in particular compounds 1-3 and 5, with IC50 values of 7.3 ± 0.5, 6.0 ± 0.3, 5.6 ± 0.3, and 5.4 ± 2.5 μM, respectively.

Do arginine metabolites have a role in periodontitis due to smoking? A new perspective

OBJECTIVES

Cigarette consumption is common around the world and besides its negative effects on health, and its effects on periodontitis draw attention. Arginine metabolites are involved in the pathogenesis of several systemic inflammatory diseases' including cardiovascular diseases. Our aim was to determine periodontitis and healthy individuals' arginine metabolites and IL-6 levels in saliva and serum and to evaluate those according to smoking status.

MATERIALS AND METHODS

The study consisted of four groups: healthy individuals (control [C]; n = 20), smokers with healthy periodontium (S-C; n = 20), nonsmokers with Stage-III Grade-B generalized periodontitis (P; n = 20) and smokers with Stage-III Grade-C generalized periodontitis (S-P; n = 18). Periodontal parameters were measured. Analysis of methylated arginine metabolites was performed by LC-MS/MS, and IL-6 levels were determined by ELISA kits.

RESULTS

In nonsmokers, salivary concentrations of asymmetric dimethylarginine (ADMA) and symmetrical dimethylarginine (SDMA) were higher in the periodontitis than control (p < 0.001, p = 0.010). Smokers with periodontitis exhibited higher ADMA (p = 0.033, p < 0.001) and arginine (p = 0.030, p = 0.001) saliva concentrations than smoking and nonsmoking controls.

CONCLUSIONS

Our results demonstrated that salivary concentrations of ADMA and SDMA were associated with periodontitis. Smoking increased ADMA, SDMA and NG -monomethyl L-arginine (L-NMMA) levels in serum only in periodontitis patients.

The Potential Role of Nitric Oxide as a Therapeutic Agent against SARS-CoV-2 Infection

The global coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become the greatest worldwide public health threat of this century, which may predispose multi-organ failure (especially the lung) and death despite numerous mild and moderate symptoms. Recent studies have unraveled the molecular and clinical characteristics of the infectivity, pathogenicity, and immune evasion of SARS-CoV-2 and thus improved the development of many different therapeutic strategies to combat COVID-19, including treatment and prevention. Previous studies have indicated that nitric oxide (NO) is an antimicrobial and anti-inflammatory molecule with key roles in pulmonary vascular function in the context of viral infections and other pulmonary disease states. This review summarized the recent advances of the pathogenesis of SARS-CoV-2, and accordingly elaborated on the potential application of NO in the management of patients with COVID-19 through antiviral activities and anti-inflammatory properties, which mitigate the propagation of this disease. Although there are some limits of NO in the treatment of COVID-19, it might be a worthy candidate in the multiple stages of COVID-19 prevention or therapy.

Levels of nitric oxide in smokers and nonsmokers with chronic periodontitis before and after nonsurgical periodontal treatment

Introduction

The purpose of this study was to determine the level of nitric oxide (NO) in both serum and saliva of smokers and nonsmokers with chronic periodontitis before and after scaling and root planing, as well as to compare the same (NO levels) with the severity of periodontitis.

Materials and Methods

Sixty people took part in the study and were divided into three groups. The control group (Group I) involved 20 patients who were nonsmokers with healthy periodontium. The other two groups included 20 patients each, where Group II was nonsmokers with chronic periodontitis and Group III was smokers with chronic periodontitis. In addition, NO generation was quantified indirectly in this study using the Griess reaction to determine the nitrite level in serum and saliva.

Results

The mean value of salivary and serum NO was higher in Group III than in Group II, and NO decreased considerably (P < 0.01) in both Groups II and III after treatment compared to before treatment.

Conclusion

Serum and salivary NO levels can be used as a good predictor of the inflammatory condition of the periodontium in smokers.

From the Bush to the Brain: Preclinical Stages of Ethnobotanical Anti-Inflammatory and Neuroprotective Drug Discovery-An Australian Example

The Australian rainforest is a rich source of medicinal plants that have evolved in the face of dramatic environmental challenges over a million years due to its prolonged geographical isolation from other continents. The rainforest consists of an inherent richness of plant secondary metabolites that are the most intense in the rainforest. The search for more potent and more bioavailable compounds from other plant sources is ongoing, and our short review will outline the pathways from the discovery of bioactive plants to the structural identification of active compounds, testing for potency, and then neuroprotection in a triculture system, and finally, the validation in an appropriate neuro-inflammatory mouse model, using some examples from our current research. We will focus on neuroinflammation as a potential treatment target for neurodegenerative diseases including multiple sclerosis (MS), Parkinson's (PD), and Alzheimer's disease (AD) for these plant-derived, anti-inflammatory molecules and highlight cytokine suppressive anti-inflammatory drugs (CSAIDs) as a better alternative to conventional nonsteroidal anti-inflammatory drugs (NSAIDs) to treat neuroinflammatory disorders.

Asymmetric and symmetric dimethylarginine gingival crevicular fluid levels in periodontitis

OBJECTIVE

This study aimed to evaluate the level of ADMA (asymmetric dimethylarginine), SDMA (symmetric dimethylarginine), and IL-1β (Interleukin-1β) in gingival crevicular fluid (GCF) from periodontitis patients and control subjects.

BACKGROUND

ADMA and SDMA are potentially hazardous non-proteinogenic amino acids that limit nitric oxide (NO) synthesis and have many functions in various human disorders. ADMA causes a structural change in nitric oxide synthase, while SDMA blocks arginine cell uptake. Increased plasma ADMA has been widely recognized as a "trigger" initiating impaired NO bioavailability and vascular dysfunction, which ultimately leads to oxidative stress.

METHODS

Twenty-five patients with periodontitis (P) (Stage III, Grade C, n = 25) and 20 control (C) subjects were included in the study. The IL-1β level of GCF was measured by enzyme immunoassay (ELISA) and ADMA and SDMA by liquid chromatography-mass spectrometry (LC-MS/MS).

RESULTS

Periodontitis patients had higher clinical parameters than controls (p < .001). Levels of IL-1β, ADMA and SDMA GCF were statistically significantly higher in group P than in group C (respectively; p = .003, p < .0001, p < .0001). There was no difference in the ADMA/SDMA ratio (p = .312) between the groups. There were significant positive correlations between clinical periodontal parameters and IL-1β, ADMA, and SDMA levels (p < .05). ADMA and SDMA levels were significantly correlated with IL-1β (p < .05).

CONCLUSIONS

These findings suggest that ADMA and SDMA may be involved in the pathogenesis of the periodontal disease.

Photobiomodulation ameliorates inflammatory parameters in fibroblast-like synoviocytes and experimental animal models of rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) is a chronic destructive inflammatory disease that afflicts over one percent of the world’s population. Current pharmacological treatments remain relatively ineffective. In this context, photobiomodulation (PBM) is a potential resource for the treatment of RA. This study investigates investigate the anti-arthritic effects and related mechanisms of PBM on fibroblast-like synoviocytes (FLSs) from RA patients and a mouse model of collagen-induced arthritis (CIA).

Methods

The RA-FLSs were irradiated with a light emitting diode (LED) at a wavelength of 610 nm for 20 min, and the corresponding power intensities were 5 and 10 mW/cm2. After the LED irradiation, cell viability, proliferation, migration, and invasion assays were performed. Male DBA/1J mice were used to establish an animal model of CIA. Light stimulation with 10 mW/cm2 was applied to the ankle joints via direct contact with the skin for 40 min, daily for 2 weeks.

Results and Discussion

PBM significantly reduced tumor necrosis factor (TNF)-α-induced increase in proliferation, migration, and invasion in RA-FLSs, and downregulated the activation of nuclear factor-κappa B (NF-κB) and NLRP3 inflammasome by TNF-α. Moreover, PBM greatly inhibited the induction and development of CIA, resulting in the inhibition of synovial inflammation and cartilage degradation. PBM therapy decreased the serum levels of pro-inflammatory cytokines, while increasing the anti-inflammatory cytokines. PBM suppressed the translocation of NF-κB and activation of NLRP3 inflammasome in the ankle joint. Furthermore, PBM showed a more pronounced anti-arthritic effect when combined with methotrexate (MTX), a disease-modifying anti-rheumatic drug (DMARD). The results showed that the effectiveness of MTX + PBM in CIA is superior to that of either MTX or PBM and that both work synergistically. Therefore, PBM with LED may be a potential therapeutic intervention for against RA.

Extract of Aster koraiensis Nakai Leaf Ameliorates Memory Dysfunction via Anti-inflammatory Action

Aster koraiensis Nakai (AK) leaf reportedly ameliorates health problems, such as diabetes. However, the effects of AK on cognitive dysfunction or memory impairment remain unclear. This study investigated whether AK leaf extract could attenuate cognitive impairment. We found that AK extract reduced the production of nitric oxide (NO), tumour necrosis factor (TNF)-α, phosphorylated-tau (p-tau), and the expression of inflammatory proteins in lipopolysaccharide- or amyloid-β-treated cells. AK extract exhibited inhibitory activity of control specific binding on N-methyl-D-aspartate (NMDA) receptors. Scopolamine-induced AD models were used chronically in rats and acutely in mice. Relative to negative controls (NC), hippocampal choline acetyltransferase (ChAT) and B-cell lymphoma 2 (Bcl2) activity was increased in rats chronically treated with scopolamine and fed an AK extract-containing diet. In the Y-maze test, spontaneous alterations were increased in the AK extract-fed groups compared to NC. Rats administered AK extract showed increased escape latency in the passive avoidance test. In the hippocampus of rats fed a high-AK extract diet (AKH), the expression of neuroactive ligand–receptor interaction-related genes, including Npy2r, Htr2c, and Rxfp1, was significantly altered. In the Morris water maze assay of mice acutely treated with scopolamine, the swimming times in the target quadrant of AK extract-treated groups increased significantly to the levels of the Donepezil and normal groups. We used Tg6799 Aβ-overexpressing 5XFAD transgenic mice to investigate Aβ accumulation in animals. In the AD model using 5XFAD, the administration of AK extract decreased amyloid-β (Aβ) accumulation and increased the number of NeuN antibody-reactive cells in the subiculum relative to the control group. In conclusion, AK extract ameliorated memory dysfunction by modulating ChAT activity and Bcl2-related anti-apoptotic pathways, affecting the expression of neuroactive ligand–receptor interaction-related genes and inhibiting Aβ accumulation. Therefore, AK extract could be a functional material improving cognition and memory.

Thermosusceptible Nitric-Oxide-Releasing Nitrogel for Strengthening Antitumor Immune Responses with Tumor Collagen Diminution and Deep Tissue Delivery during NIR Laser-Assisted Photoimmunotherapy

Combined cancer immunotherapy has demonstrated promising potential with an amplified antitumor response and immunosuppressive tumor microenvironment (TME) modulation. However, one of the main issues that cause treatment failure is the poor diffusion and insufficient penetration of therapeutic and immunomodulatory agents in solid tumors. Herein, a cancer treatment approach that combines photothermal therapy (PTT) and nitric oxide (NO) gas therapy for tumor extracellular matrix (ECM) degradation, along with NLG919, an indoleamine 2,3-dioxygenase (IDO) inhibitor that reduces tryptophan catabolism to kynurenine, and DMXAA, a stimulator of interferon gene (STING) agonist that stimulates antigen cross-presentation, is proposed to overcome this issue. Upon NIR (808 nm) laser irradiation, NO-GEL achieved the desired thermal ablation by releasing sufficient tumor antigens through immunogenic cell death (ICD). NO delivery triggered local diffusion of excess NO gas for effectively degrading tumor collagen in the ECM, homogeneously delivered NLG919 throughout the tumor tissue, inhibited IDO expression that was upregulated by PTT, and reduced the immune suppressive activities. The sustained release of DMXAA prolonged dendritic cell maturation and CD8⁺ T cell activation against the tumor. In summary, NO-GEL therapeutics offer a significant tumor regression with PTT and STING agonist combination that stimulates a durable antitumor immune response. Additional unification of IDO inhibition during PTT supplements the immunotherapy by reducing the T cell apoptosis and immune suppressive cell infiltration to TME. NO-GEL with the STING agonist and IDO inhibitor is an effective therapeutic combination to counter possible limitations during solid tumor immunotherapy.

Methylene blue dosing strategies in critically ill adults with shock-A retrospective cohort study

Background

Shock increases mortality in the critically ill and the mainstay of therapy is the administration of vasopressor agents to achieve hemodynamic targets. In the past, studies have found that the NO-pathway antagonist methylene blue improves hemodynamics. However, the optimal dosing strategy remains elusive. Therefore, we investigated the hemodynamic and ICU outcome parameters of three different dosing strategies for methylene blue.

Methods

We performed a retrospective cohort study of patients in shock treated with methylene blue. Shock was defined as norepinephrine dose >0.1 μg/kg/min and serum lactate level >2 mmol/l at the start of methylene blue administration. Different demographic variables, ICU treatment, and outcome parameters were evaluated. To compare the differences in the administration of vasopressors or inotropes, the vasoactive inotropic score (VIS) was calculated at different time points after starting the administration of methylene blue. Response to methylene blue or mortality at 28 days were assessed.

Results

262 patients from July 2014 to October 2019 received methylene blue. 209 patients met the inclusion criteria. Three different dosing strategies were identified: bolus injection followed by continuous infusion (n = 111), bolus injection only (no continuous infusion; n = 59) or continuous infusion only (no bolus prior; n = 39). The groups did not differ in demographics, ICU scoring system, or comorbidities. In all groups, VIS decreased over time, indicating improved hemodynamics. Cardiogenic shock and higher doses of norepinephrine increased the chance of responding to methylene blue, while bolus only decreased the chance of responding to methylene blue treatment. 28-day mortality increased with higher SAPSII scores and higher serum lactate levels, while bolus injection followed by continuous infusion decreased 28-day mortality. No severe side effects were noted.

Conclusion

In this cohort, methylene blue as a bolus injection followed by continuous infusion was associated with a reduced 28-day mortality in patients with shock. Prospective studies are needed to systematically evaluate the role of methylene blue in the treatment of shock.

Mechanisms of Foreign Body Response Mitigation by Nitric Oxide Release

Implantable glucose biosensors provide real-time information about blood glucose fluctuations, but their utility and accuracy are time-limited due to the foreign body response (FBR) following their insertion beneath the skin. The slow release of nitric oxide (NO), a gasotransmitter with inflammation regulatory properties, from a sensor surface has been shown to dramatically improve sensors' analytical biocompatibility by reducing the overall FBR response. Indeed, work in a porcine model suggests that as long as the implants (sensors) continue to release NO, even at low levels, the inflammatory cell infiltration and resulting collagen density are lessened. While these studies strongly support the benefits of NO release in mitigating the FBR, the mechanisms through which exogenous NO acts on the surrounding tissue, especially under the condition of hyperglycemia, remain vague. Such knowledge would inform strategies to refine appropriate NO dosage and release kinetics for optimal therapeutic activity. In this study, we evaluated mediator, immune cell, and mRNA expression profiles in the local tissue microenvironment surrounding implanted sensors as a function of NO release, diabetes, and implantation duration. A custom porcine wound healing-centric multiplex gene array was developed for nanoString barcoding analysis. Tissues adjacent to sensors with sustained NO release abrogated the implant-induced acute and chronic FBR through modulation of the tissue-specific immune chemokine and cytokine microenvironment, resulting in decreased cellular recruitment, proliferation, and activation at both the acute (7-d) and chronic (14-d) phases of the FBR. Further, we found that sustained NO release abrogated the implant-induced acute and chronic foreign body response through modulation of mRNA encoding for key immunological signaling molecules and pathways, including STAT1 and multiple STAT1 targets including MAPK14, IRAK4, MMP2, and CXCL10. The condition of diabetes promoted a more robust FBR to the implants, which was also controlled by sustained NO release.

Regulatory Role of Nitric Oxide in Cutaneous Inflammation

Nitric oxide (NO), a signaling molecule, regulates biological functions in multiple organs/tissues, including the epidermis, where it impacts permeability barrier homeostasis, wound healing, and antimicrobial defense. In addition, NO participates in cutaneous inflammation, where it exhibits pro-inflammatory properties via the cyclooxygenase/prostaglandin pathway, migration of inflammatory cells, and cytokine production. Yet, NO can also inhibit cutaneous inflammation through inhibition of T cell proliferation and leukocyte migration/infiltration, enhancement of T cell apoptosis, as well as through down-regulation of cytokine production. Topical applications of NO-releasing products can alleviate atopic dermatitis in humans and in murine disease models. The underlying mechanisms of these discrepant effects of NO on cutaneous inflammation remain unknown. In this review, we briefly review the regulatory role of NO in cutaneous inflammation and its potential, underlying mechanisms.

Critical role of nitric oxide in impeding COVID-19 transmission and prevention: a promising possibility

COVID-19 is a serious respiratory infection caused by a beta-coronavirus that is closely linked to SARS. Hypoxemia is a symptom of infection, which is accompanied by acute respiratory distress syndrome (ARDS). Augmenting supplementary oxygen may not always improve oxygen saturation; reversing hypoxemia in COVID-19 necessitates sophisticated means to promote oxygen transfer from alveoli to blood. Inhaled nitric oxide (iNO) has been shown to inhibit the multiplication of the respiratory coronavirus, a property that distinguishes it from other vasodilators. These findings imply that NO may have a crucial role in the therapy of COVID-19, indicating research into optimal methods to restore pulmonary physiology. According to clinical and experimental data, NO is a selective vasodilator proven to restore oxygenation by helping to normalize shunts and ventilation/perfusion mismatches. This study examines the role of NO in COVID-19 in terms of its specific physiological and biochemical properties, as well as the possibility of using inhaled NO as a standard therapy. We have also discussed how NO could be used to prevent and cure COVID-19, in addition to the limitations of NO.

Steroid Phobia: Is There a Basis? A Review of Topical Steroid Safety, Addiction and Withdrawal

There is a growing concern amongst patients about topical corticosteroid (TCS) side effects, with increasing discussion of topical steroid addiction (TSA) and topical steroid withdrawal (TSW) particularly on social media platforms. However, the acceptance of TSA/TSW as a distinct condition remains controversial within the dermatological community. We conducted a literature search using PubMed, MEDLINE, Cochrane Library, Google Scholar, Embase and Web of Science to identify original articles addressing TSA/TSW. We described the definition and reported clinical features of TSA/TSW including its classification into erythemato-edematous and papulopustular subtype. To assess the validity of TSA/TSW, we summarised and objectively appraised the postulated mechanisms for this condition, including tachyphylaxis, dysregulation of glucocorticoid receptors, rebound vasodilation and impaired skin barrier leading to a cytokine cascade. Understanding the evidence including its limitations and uncertainties highlights areas for future research and helps medical practitioners better counsel and provide care to patients who may be experiencing or who have concerns about TSA/TSW.

Veillonellaceae family members uniquely alter the cervical metabolic microenvironment in a human three-dimensional epithelial model

Bacterial vaginosis (BV) is a gynecologic disorder characterized by a shift in cervicovaginal microbiota from Lactobacillus spp. dominance to a polymicrobial biofilm composed of diverse anaerobes. We utilized a well-characterized human three-dimensional cervical epithelial cell model in conjunction with untargeted metabolomics and immunoproteomics analyses to determine the immunometabolic contribution of three members of the Veillonellaceae family: Veillonella atypica, Veillonella montpellierensis and Megasphaera micronuciformis at this site. We found that Veillonella spp. infections induced significant elevation of polyamines. M. micronuciformis infections significantly increased soluble inflammatory mediators, induced moderate levels of cell cytotoxicity, and accumulation of cell membrane lipids relative to Veillonella spp. Notably, both V. atypica and V. montpellierensis infections resulted in consumption of lactate, a key metabolite linked to gynecologic and reproductive health. Collectively our approach and data provide unique insights into the specific contributions of Veillonellaceae members to the pathogenesis of BV and women's health.

Anti-Inflammatory and Immunomodulatory Properties of Fermented Plant Foods

Fermented plant foods are gaining wide interest worldwide as healthy foods due to their unique sensory features and their health-promoting potentials, such as antiobesity, antidiabetic, antihypertensive, and anticarcinogenic activities. Many fermented foods are a rich source of nutrients, phytochemicals, bioactive compounds, and probiotic microbes. The excellent biological activities of these functional foods, such as anti-inflammatory and immunomodulatory functions, are widely attributable to their high antioxidant content and lactic acid-producing bacteria (LAB). LAB contribute to the maintenance of a healthy gut microbiota composition and improvement of local and systemic immunity. Besides, antioxidant compounds are involved in several functional properties of fermented plant products by neutralizing free radicals, regulating antioxidant enzyme activities, reducing oxidative stress, ameliorating inflammatory responses, and enhancing immune system performance. Therefore, these products may protect against chronic inflammatory diseases, which are known as the leading cause of mortality worldwide. Given that a large body of evidence supports the role of fermented plant foods in health promotion and disease prevention, we aim to discuss the potential anti-inflammatory and immunomodulatory properties of selected fermented plant foods, including berries, cabbage, and soybean products, and their effects on gut microbiota.

The role of NO in COVID-19 and potential therapeutic strategies

Nitric oxide (NO) is a free radical playing an important pathophysiological role in cardiovascular and immune systems. Recent studies reported that NO levels were significantly lower in patients with COVID-19, which was suggested to be closely related to vascular dysfunction and immune inflammation among them. In this review, we examine the potential role of NO during SARS-CoV-2 infection from the perspective of the unique physical, chemical and biological properties and potential mechanisms of NO in COVID-19, as well as possible therapeutic strategies using inhaled NO. We also discuss the limits of NO treatment, and the future application of this approach in prevention and therapy of COVID-19.

The impact of l-arginine supplementation on the enteral phase of experimental Trichinella spiralis infection in treated and untreated mice

The role of nitric oxide (NO) in the immunopathological response during Trichinella spiralis (T. spiralis) infection remains controversial. The amino acid, l-arginine is a NO precursor commonly used by athletes and bodybuilders as a protein supplement. As to our knowledge, there are no published studies which have tested the effect of l-arginine on the intestinal phase of experimental trichinellosis. The present work aims to investigate the effect of l-arginine on the enteral phase of experimental T. spiralis infection in albendazole-treated and untreated mice. Forty BALB/C mice infected orally with T. spiralis larvae were divided into 4 groups as follows: Group A were infected and untreated (control) mice, Group B received albendazole alone, Group C received l-arginine alone, and Group D received both l-arginine and albendazole. Compared to the control group, l-arginine supplementation showed; a significant increase in the intestinal adult worm burden, a significantly high inducible NO synthase (iNOS) expression, elevated immune markers; tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), and enhanced apoptosis. Albendazole treated-group had a significant reduction in the adult worm number (90.9%), while combined albendazole-arginine regimen showed a lower percentage of worm reduction (72.7%). During the enteral phase of T. spiralis infection, l-arginine supplementation should be taken cautiously, as it may modulate the proinflammatory immune response and subsequently affect the outcome of the infection and/or treatment.

Metabolic syndrome agravates cardiovascular, oxidative and inflammatory dysfunction during the acute phase of Trypanosoma cruzi infection in mice

We evaluated the influence of metabolic syndrome (MS) on acute Trypanosoma cruzi infection. Obese Swiss mice, 70 days of age, were subjected to intraperitoneal infection with 5 × 102 trypomastigotes of the Y strain. Cardiovascular, oxidative, inflammatory, and metabolic parameters were evaluated in infected and non-infected mice. We observed higher parasitaemia in the infected obese group (IOG) than in the infected control group (ICG) 13 and 15 days post-infection. All IOG animals died by 19 days post-infection (dpi), whereas 87.5% of the ICG survived to 30 days. Increased plasma nitrite levels in adipose tissue and the aorta were observed in the IOG. Higher INF-γ and MCP-1 concentrations and lower IL-10 concentrations were observed in the IOG compared to those in the ICG. Decreased insulin sensitivity was observed in obese animals, which was accentuated after infection. Higher parasitic loads were found in adipose and hepatic tissue, and increases in oxidative stress in cardiac, hepatic, and adipose tissues were characteristics of the IOG group. Thus, MS exacerbates experimental Chagas disease, resulting in greater damage and decreased survival in infected animals, and might be a warning sign that MS can influence other pathologies.

Cytotoxicity to Five Cancer Cell Lines of the Respiratory Tract System and Anti-inflammatory Activity of Thai Traditional Remedy

A Thai traditional remedy called Benchalokawichian (BLW) consists of 5 plant species, Ficus racemosa, Capparis micracantha, Clerodendrum petasites, Harrisonia perforata, and Tiliacora triandra. It has long been used in Thai traditional medicine to reduce fever in respiratory tract infection, but there is no report on either cytotoxicity against cancer cell lines of the respiratory tract system or anti-inflammatory effect. Thus, the objectives of this research were to investigate the cytotoxic activity of the ethanolic and water extracts of BLW, its single plant ingredients and its isolated compounds against 5 cancer cell lines of the respiratory tract, by SRB assay. Anti-inflammatory activity of all extracts and compounds was also tested by using lipopolysaccharide-induced nitric oxide (NO) in RAW 264.7 cells. The main compounds were isolated by high-performance liquid chromatography and compared with BLW and plant ingredients. A major compound of BLW and H. perforata ethanolic extracts is perforatic acid, which inhibited the growth of 2 lung cancer cell lines, A549 and H226, with IC50 values of 6.7 and 13.2 µg/mL. The ethanolic extract of BLW and T. triandra showed cytotoxic activity against all cancer cell lines with IC50 values in the range of 10.1 to 45.2 µg/mL. In contrast, all EtOH extracts showed moderate anti-inflammatory activity, but the water extract had no inhibitory effect on either activity. Pectolinarigenin and O-methyllaloptaeroxyrin, 2 minor compounds, exhibited NO inhibitory effect with IC50 values of 7.1 and 7.9 µg/mL, respectively, whereas perforatic acid was inactive (>50 µg/mL). Moreover, pectolinarigenin showed high cytotoxic activity against all cancer cell lines of the respiratory system with IC50 values in the range of 1.9 to 9.1 µg/mL. As a result, these 2 minor compounds can be used as markers for quality control of BLW for anti-inflammatory activity. Perforatic acid and pectolinarigenin are of interest for further study on their cytotoxic mechanism. Remarkably, T. triandra, one of the plant components of BLW, is possibly the source of the active cytotoxic compounds.

Regulation of Vaginal Microbiome by Nitric Oxide

In this review, the composition and regulation of vaginal microbiome that displays an apparent microbial diversity and interacts with other microbiota in the body are presented. The role of nitric oxide (NO) in the regulation of vaginal microflora in which lactobacillus species typically dominate has been delineated from the perspective of maintaining gynecologic ecosystem and prevention of onset of bacteriostatic vaginosis (BV) and/or sexually transmitted diseases (STD) including HIV-1 transmission. The interactions between NO and vaginal microbiome and its influence on the levels of Lactobacillus, hormones and other components are described. The recent progress, such as NO drugs, probiotic Lactobacilli and Lactobacillus microbots, that can be explored to alleviate abnormality of vagina microbiome, is also discussed. An identification of Oral-GI-Vagina axis, as well as the relationship between NO and Lactobacillus regulation in the healthy or pathological status of vagina microbiome, surely offers the advanced drug delivery option against BV or STD including AIDS.

White blood cell count and all-cause and cause-specific mortality in the Guangzhou biobank cohort study

Background

Several studies have shown positive associations between higher WBC count and deaths from all-causes, CHD, stroke and cancer among occidental populations or developed countries of Asia. No study on the association of WBC count with all-cause and cause-specific mortality in Chinese populations was reported. We studied this using prospective data from a large Chinese cohort.

Methods

We used prospective data from the Guangzhou Biobank Cohort Study (GBCS), a total of 29,925 participants in present study. A Cox proportional hazards regression model was used to estimate the hazard ratios (HR) and 95% confidence interval (CI).

Results

The hazard ratios (HR) for all-cause, CHD, and respiratory disease mortality for the highest decile of WBC count (women > 8.2 × 10⁹/L; men > 8.8 × 10⁹/L) was 1.83 (95% confidence interval (CI) 1.54, 2.17), 3.02 (95% CI 1.84, 4.98) and 2.52 (95% CI 1.49, 4.27), respectively, after adjusting for multiple potential confounders. The associations were similar when deaths during the first 2 years of follow-up were excluded. After further adjusting for pulmonary function, the highest decile of WBC count was associated with 90% higher risk of respiratory disease mortality (HR 1.90, 95% CI 1.08, 3.33). No evidence for an association between higher WBC count and cancer mortality was found. Sub-type analysis showed that only granulocyte count remained significantly predictive of all-cause, CHD, and respiratory disease mortality.

Conclusions

Elevated WBC, specifically granulocyte, count was associated with all-cause, CHD and respiratory mortality in southern Chinese. Further investigation is warranted to clarify whether decreasing inflammation would attenuate WBC count associated mortality.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6073-6) contains supplementary material, which is available to authorized users.

Hormesis of methylmercury-human serum albumin conjugate on N9 microglia via ERK/MAPKs and STAT3 signaling pathways

Methylmercury (MeHg⁺) is an extremely toxic organomercury cation that can induce severe neurological damage. Once it enters the body, methylmercury binds to amino acids or proteins containing free sulfhydryl groups. In particular, methylmercury is known to bind with human serum albumin (HSA) in human plasma; however, the effects of methylmercury-HSA conjugate (MeHg-HSA) on the central nervous system (CNS) are not fully understood. In the present study, we used the microglial cell line N9 as the target cells to evaluate the effect of MeHg-HSA on physiological function of the CNS preliminarily. The various factors in the cell culture were monitored by MTT assay, total lactate dehydrogenase assay, ELISA, qPCR, Western blot and flow cytometry techniques. The results showed that low-dose treatment with MeHg-HSA activated N9 cells, promoting cell proliferation and total cell number, enhancing NO and intracellular Ca²⁺ levels, and suppressing the release of TNFα and IL1β without cytotoxic effects; while high-dose MeHg-HSA exhibited cytotoxic effects on N9 cells, including promoting cell death and increasing the secretion of TNFα and IL1β. These results indicate that MeHg-HSA causes hormesis in microglia N9 cells. Furthermore, ERK/MAPKs and STAT3 signaling pathways related to the hormesis of MeHg-HSA on N9 cells. In addition, low dose of MeHg-HSA might be viewed as something very close to a lowest observed adverse effect level (LOAEL) for N9 cells. These findings will be useful for investigating the hormesis mechanism of MeHg⁺ and exploring the specific functions of MeHg-sulfhydryl conjugates on the central nervous system.

Investigation of the Biocompatibility of Surgical Masks

According to the ISO10993-1 standard medical devices should be evaluated before marketing. Although there are studies that monitor the toxicity of several marketed medical devices, none of them describe the toxicity of masks that are widely used to avoid occupational exposure to biological hazard or toxic chemicals. The aim of this study was to evaluate the biocompatibility of eight purchased surgical masks of different brands, investigating their cytotoxicity and inflammation inducing capacity. Cytotoxicity was assessed via the MTT cell viability assay and inflammation was monitored by measuring nitrite, kynurenine and tryptophan levels. A preliminary study revealed that four samples were capable of killing L929 cells. Therefore the materials composing these masks were also evaluated separately. While the exposure to non-woven materials did not involve any changes in cell survival, exposing cells to elastic and sponge materials led to death in significant levels. Also, significant increases in nitrite levels with a decrease in tryptophan and kynurenine levels were obtained with cells treated with these materials, suggesting an inflammatory response that could be related to the observed cytotoxicity. Our studies revealed that the half of the randomly collected masks did not suit the biocompatibility criteria established by the ISO10993-1 standard, which is a quite unexpected result.

Transforming growth factor-β1 induces cerebrovascular dysfunction and astrogliosis through angiotensin II type 1 receptor-mediated signaling pathways

Transgenic mice constitutively overexpressing the cytokine transforming growth factor-β1 (TGF-β1) (TGF mice) display cerebrovascular alterations as seen in Alzheimer's disease (AD) and vascular cognitive impairment and dementia (VCID), but no or only subtle cognitive deficits. TGF-β1 may exert part of its deleterious effects through interactions with angiotensin II (AngII) type 1 receptor (AT1R) signaling pathways. We test such interactions in the brain and cerebral vessels of TGF mice by measuring cerebrovascular reactivity, levels of protein markers of vascular fibrosis, nitric oxide synthase activity, astrogliosis, and mnemonic performance in mice treated (6 months) with the AT1R blocker losartan (10 mg/kg per day) or the angiotensin converting enzyme inhibitor enalapril (3 mg/kg per day). Both treatments restored the severely impaired cerebrovascular reactivity to acetylcholine, calcitonin gene-related peptide, endothelin-1, and the baseline availability of nitric oxide in aged TGF mice. Losartan, but not enalapril, significantly reduced astrogliosis and cerebrovascular levels of profibrotic protein connective tissue growth factor while raising levels of antifibrotic enzyme matrix metallopeptidase-9. Memory was unaffected by aging and treatments. The results suggest a pivotal role for AngII in TGF-β1-induced cerebrovascular dysfunction and neuroinflammation through AT1R-mediated mechanisms. Further, they suggest that AngII blockers could be appropriate against vasculopathies and astrogliosis associated with AD and VCID.

The Consequences of Being in an Infectious Biofilm: Microenvironmental Conditions Governing Antibiotic Tolerance

The main driver behind biofilm research is the desire to understand the mechanisms governing the antibiotic tolerance of biofilm-growing bacteria found in chronic bacterial infections. Rather than genetic traits, several physical and chemical traits of the biofilm have been shown to be attributable to antibiotic tolerance. During infection, bacteria in biofilms exhibit slow growth and a low metabolic state due to O₂ limitation imposed by intense O₂ consumption of polymorphonuclear leukocytes or metabolically active bacteria in the biofilm periphery. Due to variable O₂ availability throughout the infection, pathogen growth can involve aerobic, microaerobic and anaerobic metabolism. This has serious implications for the antibiotic treatment of infections (e.g., in chronic wounds or in the chronic lung infection of cystic fibrosis patients), as antibiotics are usually optimized for aerobic, fast-growing bacteria. This review summarizes knowledge about the links between the microenvironment of biofilms in chronic infections and their tolerance against antibiotics.

Inhibitory effect of moschamine isolated from Carthamus tinctorius on LPS-induced inflammatory mediators via AP-1 and STAT1/3 inactivation in RAW 264.7 macrophages

Seeds of Carthamus tinctorius L. (Compositae) have been used in Korean traditional medicines for the treatment of cardiovascular and bone diseases. In this study, we investigated the anti-inflammatory effects of known serotonin derivatives (1-9) isolated from the ethyl acetate (EtOAc) soluble fraction from the seeds of C. tinctorius. Compound 2, identified as moschamine, most potently inhibited lipopolysaccharide (LPS)-induced production of prostaglandin E₂ (PGE₂) and nitric oxide (NO) in RAW 264.7 macrophages. Moschamine concentration-dependently inhibited LPS-induced PGE₂ and NO production in RAW 264.7 macrophages. Consistent with these findings, moschamine suppressed the protein and mRNA levels of cyclooxygenase-2 (COX-2), microsomal prostaglandin E₂ synthase (mPGES)-1, and inducible NO synthase (iNOS), interleukin (IL)-6, and IL-1β. In addition, pretreatment of moschamine significantly inhibited LPS-stimulated the transcriptional activity of activator protein-1 (AP-1) and the phosphorylation of signal transducer and activator of transcription (STAT)1/3 in RAW 264.7 macrophages. Moreover, moschamine inhibited LPS-induced the phosphorylation of p38 mitogen-activated protein kinase (p38) and extracellular signal-regulated kinase (ERK), but it had no effect on c-Jun N-terminal kinase (JNK). These results suggest that the mechanism of anti-inflammatory activity of moschamine is associated with the downregulation of COX-2, mPGES-1, iNOS, IL-6, and IL-1β expression through the suppression of AP-1 and STAT1/3 activation in LPS-induced RAW 264.7 macrophages.

Asymmetric Dimethylarginine Contributes to the Impaired Response to Erythropoietin in CKD-Anemia

Erythropoietin-resistant anemia is associated with adverse cardiovascular events in patients with ESRD, but the underlying mechanism remains unclear. Here, we evaluated the role of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA). In 54 patients with advanced CKD, erythrocyte but not plasma ADMA levels independently associated with low hemoglobin values, although levels of both types of ADMA were elevated compared with those in healthy volunteers. Furthermore, erythrocyte ADMA level associated with the erythropoietin resistance index in patients receiving a weekly injected dose of erythropoiesis-stimulating agents standardized for hemoglobin levels and body weight, whereas it correlated with the erythropoietin demand index (plasma erythropoietin units divided by the hemoglobin value) in patients not receiving erythropoiesis-stimulating agents. Compared with sham-operated controls, wild-type mice with 5/6 subtotal nephrectomy (Nx), a remnant kidney model with advanced CKD, had decreased hemoglobin, hematocrit, and mean corpuscular volume values but increased erythrocyte and plasma ADMA and plasma erythropoietin levels. In comparison, dimethylarginine dimethlaminohydrolase-1 transgenic (DDAH-1 Tg) mice, which efficiently metabolized ADMA, had significant improvements in all of the values except those for erythropoietin after 5/6 Nx. Additionally, wild-type Nx mice, but not DDAH-1 Tg Nx mice, had reduced splenic gene expression of erythropoietin receptor and erythroferrone, which regulates iron metabolism in response to erythropoietin. This study suggests that erythrocyte ADMA accumulation contributes to impaired response to erythropoietin in predialysis patients and advanced CKD mice via suppression of erythropoietin receptor expression.

Increased levels of alveolar and airway exhaled nitric oxide in runners

AIM

The objective of this study was to apply extended NO analysis for measurements of NO dynamics in the lung, divided into alveolar and airway contribution, in amateur runners and marathoners.

METHODS

The athletes participated in either a marathon or a half marathon. The athletes self-reported their age, weight, height, training distance per week, competing distance, cardio-pulmonary health, atopic status, and use of tobacco. Measurements of exhaled NO (F_ENO) with estimation of alveolar NO (C_ANO) and airway flux (J_awNO), ventilation, pulse oximetry, and peak flow were performed before, immediately after, and 1 hour after completing the race.

RESULTS

At baseline the alveolar NO was higher in amateur runners, 2.9 ± 1.1 ppb (p = 0.041), and marathoners, 3.6 ± 1.9 ppb (p = 0.002), than in control subjects, 1.4 ± 0.5 ppb. J_awNO was higher in marathoners, 0.90 ± 0.02 nL s^-1 (p = 0.044), compared with controls, 0.36 ± 0.02 nL s^-1, whereas the increase in amateur runners, 0.56 ± 0.02 nL s^-1, did not attain statistical significance (p = 0.165). Immediately after the race there was a decrease in F_ENO in both amateur runners and marathoners, whereas C_ANO and J_awNO were decreased in marathoners only.

CONCLUSION

Our results support the view that there is an adaptation of the lung to exercise. Thus strenuous exercise increased both airway and alveolar NO, and this might in turn facilitate oxygen uptake.

Enterosalivary nitrate metabolism and the microbiome: Intersection of microbial metabolism, nitric oxide and diet in cardiac and pulmonary vascular health

Recent insights into the bioactivation and signaling actions of inorganic, dietary nitrate and nitrite now suggest a critical role for the microbiome in the development of cardiac and pulmonary vascular diseases. Once thought to be the inert, end-products of endothelial-derived nitric oxide (NO) heme-oxidation, nitrate and nitrite are now considered major sources of exogenous NO that exhibit enhanced vasoactive signaling activity under conditions of hypoxia and stress. The bioavailability of nitrate and nitrite depend on the enzymatic reduction of nitrate to nitrite by a unique set of bacterial nitrate reductase enzymes possessed by specific bacterial populations in the mammalian mouth and gut. The pathogenesis of pulmonary hypertension (PH), obesity, hypertension and CVD are linked to defects in NO signaling, suggesting a role for commensal oral bacteria to shape the development of PH through the formation of nitrite, NO and other bioactive nitrogen oxides. Oral supplementation with inorganic nitrate or nitrate-containing foods exert pleiotropic, beneficial vascular effects in the setting of inflammation, endothelial dysfunction, ischemia-reperfusion injury and in pre-clinical models of PH, while traditional high-nitrate dietary patterns are associated with beneficial outcomes in hypertension, obesity and CVD. These observations highlight the potential of the microbiome in the development of novel nitrate- and nitrite-based therapeutics for PH, CVD and their risk factors.

Nitazoxanide anthelmintic activity against the enteral and parenteral phases of trichinellosis in experimentally infected rats

Most of the drugs used for the treatment of trichinellosis show a limited bioavailability and a high degree of resistance. Therefore, this study aimed to characterize the anthelmintic potential activity of nitazoxanide (NTZ) in a rat model of experimental trichinellosis. Animals were divided into three groups; group I, infected and non-treated; group II, received NTZ for three days post-infection (dpi) and group III, received NTZ 30 dpi for 14 consecutive days. Treatment efficacy was assessed by Trichinella spiralis adult and larval counts, histopathological studies of the small intestine and muscles and inducible nitric oxide synthase (iNOS) expression in the small intestine. T. spiralis adult count was reduced in NTZ -treated group (66.6%) and the larval count decreased to 68.7 and 76.7% in the early and late treatment, respectively. The infected non-treated rats showed massive inflammatory cellular infiltration in the small intestines and muscles. This inflammatory response was minor in the treated groups and was accompanied by a decrease in iNOS expression. Moreover, in group III, the larvae were replaced by homogenized substance with some destructive changes in the capsule. In conclusion, NTZ showed a promising activity against enteral and more effect in parenteral phases of trichinellosis.

4,7-Dimethoxy-5-methyl-1,3-benzodioxole from Antrodia camphorata inhibits LPS-induced inflammation via suppression of NF-κB and induction HO-1 in RAW264.7 cells

Several benzenoid compounds have been isolated from Antrodia camphorata are known to have excellent anti-inflammatory activity. In this study, we investigated the anti-inflammatory potential of 4,7-dimethoxy-5-methyl-1,3-benzodioxole (DMB), one of the major benzenoid compounds isolated from the mycelia of A. camphorata. DMB significantly decreased the LPS-induced production of pro-inflammatory molecules, such as nitric oxide (NO), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in RAW264.7 cells. In addition, DMB suppressed the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose dependent manner. Moreover, DMB significantly suppressed LPS-induced nuclear translocation of nuclear factor-κB (NF-κB), and this inhibition was found to be associated with decreases in the phosphorylation and degradation of its inhibitor, inhibitory κB-α (IκB-α). Moreover, we found that DMB markedly inhibited the protein expression level of Toll-like receptor 4 (TLR4). Furthermore, treatment with DMB significantly increased hemoxygenase-1 (HO-1) expression in RAW264.7 cells, which is further confirmed by hemin, a HO-1 enhancer, significantly attenuated the LPS-induced pro-inflammatory molecules and iNOS and TLR4 protein levels. Taken together, the present study suggests that DMB may have therapeutic potential for the treatment of inflammatory diseases.

Protective effect of heme oxygenase-1 on Wistar rats with heart failure through the inhibition of inflammation and amelioration of intestinal microcirculation

BACKGROUND

Myocardial infarction (MI) has likely contributed to the increased prevalence of heart failure (HF). As a result of reduced cardiac function, splanchnic blood flow decreases, causing ischemia in villi and damage to the intestinal barrier. The induction of heme oxygenase-1 (HO-1) could prevent, or lessen the effects of stress and inflammation. Thus, the effect and mechanism thereof of HO-1 on the intestines of rats with HF was investigated.

METHODS

Male Wistar rats with heart failure through ligation of the left coronary artery were identified with an left ventricular ejection fraction of < 45% through echocardiography and then divided into various experimental groups based on the type of peritoneal injection they received [MI: saline; MI + Cobalt protoporphyrin (CoPP): CoPP solution; and MI + Tin mesoporphyrin IX dichloride (SnMP): SnMP solution]. The control group was comprised of rats without coronary ligation. Echocardiography was performed before ligation for a baseline and eight weeks after ligation in order to evaluate the cardiac function of the rats. The bacterial translocation (BT) incidence, mesenteric microcirculation, amount of endotoxins in the vein serum, ileum levels of HO-1, carbon oxide (CO), nitric oxide (NO), interleukin (IL)-10, tumour necrosis factor-α (TNF-α), and the ileum morphology were determined eight weeks after the operation.

RESULTS

The rats receiving MI + CoPP injections exhibited a recovery in cardiac function, an amelioration of mesenteric microcirculation and change in morphology, a lower BT incidence, a reduction in serum and ileac NO and TNF-α levels, and an elevation in ileac HO-1, CO, and interleukin-10 (IL-10) levels compared to the MI group (P < 0.05). The rats that received the MI + SnMP injections exhibited results inverse to the MI (P < 0.05) group.

CONCLUSIONS

HO-1 exerted a protective effect on the intestines of rats with HF by inhibiting the inflammation and amelioration of microcirculation through the CO pathway. This protective effect could be independent from the recovery of cardiac function.

[The paranasal sinuses as the nitric oxide depot]

This paper was designed to report the currently available data on physiology of the nasal cavity and paranasal sinuses together with the results of national and international investigations on the computer modeling of the air flow in these structures. Also discussed are the gas composition in the paranasal sinuses and the potential factors responsible for the changes in the concentration of nitric oxide with the chemical formula of NO in the nasal cavity and paranasal sinuses.

Nitric oxide in human gingival crevicular fluid after orthodontic force application

Nitric oxide (NO) is involved in bone remodelling and has been shown to play a role in regulating the rate of orthodontic tooth movement (OTM) in rat models. In humans, however, the role of NO in OTM remains less clear. In this study, NO concentration in gingival crevicular fluid (GCF) was measured in patients undergoing orthodontic treatment. Thirteen male participants (ages 11-18 years) planned for non-extraction fixed orthodontic therapy were recruited. Samples of GCF were collected from each maxillary central incisor and first and second molar immediately before (T0), 1h after (T1), and 3-4 days after (T2) application of light orthodontic forces. The maxillary second molars were not included in the appliance and served as controls. Measureable NO levels were consistently obtained from all sampled sites. Total NO levels showed significantly higher NO levels (p<0.05) at T1 at the buccal surfaces of the central incisors when compared to the first and second molars. The results indicate a possible role for NO in OTM at the pressure sites of incisors at early time points. Further studies are required to determine whether NO levels in the periodontal ligament tissues of human teeth during OTM are affected by a force gradient and the magnitude of the applied force.

Say "no" to spinal cord injury: is nitric oxide an option for therapeutic strategies?

PURPOSE

a literature review was made to investigate the role of nitric oxide (NO) in spinal cord injury, a pathological condition that leads to motor, sensory, and autonomic deficit. Besides, we were interested in potential therapeutic strategies interfering with NO mechanism of secondary damage.

MATERIALS

A literature search using PubMed Medline database has been performed.

RESULTS

excessive NO production after spinal cord injury promotes oxidative damage perpetuating the injury causing neuronal loss at the injured site and in the surrounding area.

CONCLUSION

different therapeutic approaches for contrasting or avoiding NO secondary damage have been studied, these include nitric oxide synthase inhibitors, compounds that interfere with inducible NO synthase expression, and molecules working as antioxidant. Further studies are needed to explain the neuroprotective or cytotoxic role of the different isoforms of NO synthase and the other mediators that take part or influence the NO cascade. In this way, it would be possible to find new therapeutic targets and furthermore to extend the experimentation to humans.

Anti-inflammatory effects of the Zingiber officinale roscoe constituent 12-dehydrogingerdione in lipopolysaccharide-stimulated Raw 264.7 cells

Ginger has long been used worldwide as a spice, seasoning, and wine and is also used as a traditional medicine. There have been no previous studies of the potential beneficial effects of the ginger constituent 12-dehydrogingerdione (12-DHGD). We investigated the anti-inflammatory effect of 12-DHGD on lipopolysaccharide (LPS)-stimulated Raw 264.7 cells. The cytotoxicity of 12-DHGD was measured using the MTT assay, and production of prostaglandin E2 (PGE2 ) and the inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α was measured by ELISA. Production of nitric oxide (NO) was measured using Griess reagent and expression of cyclooxygenase-2 (COX-2) and inducible NO (iNOS) enzymes was assessed by reverse transcriptase-polymerase chain reaction. Treatment of Raw 264.7 cells with 12-DHGD significantly inhibited LPS-stimulated production of NO (at 12-DHGD concentrations of 150 and 200 ng/ml), IL-6 (at 50, 100, 150, and 200 ng/ml), and PGE2 (at 200 ng/ml). Consistent with the effects on NO and PGE2 production, 12-DHGD treatment also inhibited the LPS-stimulated increase in iNOS and COX-2 mRNA levels. However, 12-DHGD did not affect production of IL-1β or TNF-α in response to LPS. 12-DHGD, a constituent of ginger, is a potent inhibitor of proinflammatory mediator production in Raw 264.7 macrophage cells.

Bacterial clearance in septic mice is modulated by MCP-1/CCL2 and nitric oxide

Bacterial clearance is one of the most important beneficial consequences of the innate immune response. Chemokines are important mediators controlling leukocyte trafficking and activation, whereas reactive oxygen and nitrogen species are effectors in bacterial killing. In the present work, we used in vivo and in vitro models of infections to study the role of monocyte chemoattractant protein 1 (MCP-1)/CCL2 and nitric oxide (NO) in the bacterial clearance in sepsis. Our results show that MCP-1/CCL2 and NO levels are increased in the peritoneal cavity of mice 6 h after sepsis induced by cecal ligation and puncture. Pretreatment with anti-MCP-1/CCL2 monoclonal antibodies increased the number of colony-forming units (CFUs) recovered in the peritoneal lavage fluid. Moreover, CFU counts were increased in the peritoneal fluid of CCR2 mice subjected to cecal ligation and puncture. In vitro stimulation of peritoneal macrophages with recombinant MCP-1/CCL2 reduced CFU counts in the supernatant after challenge with Escherichia coli. Conversely, treatment with anti-MCP-1/CCL2 increased CFU counts under the same experimental condition. Stimulation of cultured macrophages with MCP-1/CCL2 and interferon had a synergistic effect on NO production. Macrophages from CCL2 mice showed a consistent decrease in NO production when compared with wild-type controls after stimulation with LPS + interferon. Finally, we showed incubation of macrophages with E. coli, and the ERK inhibitor U0126 increased CFU numbers and decreased intracellular levels of NO. In conclusion, we demonstrated for the first time that MCP-1/CCL2 has a crucial role in the clearance of bacteria by mechanisms involving increased expression of inducible NO synthase and production of NO by ERK signaling pathways.

An electrochemical functional assay for the sensing of nitric oxide release induced by angiogenic factors

Nitric oxide (NO) is a critical biological mediator involved in numerous diseases. However, the short lifetime of this molecule in biological conditions can make its study in situ complicated. Here, we review some recent results on the role of NO in angiogenesis, obtained using a biocompatible microelectrode array. This simple system allowed for the quick and easy quantification of NO released from cells grown directly on the surface of the sensor. We have used this technology to demonstrate that angiogenin induces NO release, and to partially elucidate its intracellular transduction pathway.

Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O(3)) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O(3) fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O(3) fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O(3), determined from the mRNA levels of the major allergens. We conclude that O(3) can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase.