Circulating cytokines and risk of developing hypertension: A systematic review and meta-analysis.

BACKGROUND: Immune responses play a significant role in hypertension, though the importance of key inflammatory mediators remains to be defined. We used a systematic literature review and meta-analysis to study the associations between key cytokines and incident hypertension. METHODS: We performed a systematic search of Pubmed/Medline, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL), for peer-reviewed studies published up to August 2022. Incident hypertension was defined as systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg and/or the use of antihypertensive medications. Random effects meta-analyses were used to calculate pooled hazard ratios (HRs)/risk ratios (RRs) and 95% confidence intervals by cytokine levels (highest vs. lowest quartile). RESULTS: Only IL-6 and IL-1ß levels have evidence allowing for quantitative evaluation concerning the onset of hypertension. Six studies (10406 participants, 2932 incident cases) examined the association of IL-6 with incident hypertension. The highest versus lowest quartile of circulating IL-6 was associated with a significant HR/RR of hypertension (1.61, 95% CI: 1.00 to 2.60; I2 =87%). After adjusting for potential confounders, including body mass index (BMI), HR/RR was no longer significant (HR/RR: 1.24; 95% CI, 0.96 to 1.61; I2 = 56%). About IL-1ß, neither the crude (HR/RR: 1.03; 95% CI, 0.60 to 1.76; n = 2) nor multivariate analysis (HR/RR: 0.97, 95% CI, 0.60 to 1.56; n = 2) suggested a significant association with the risk of developing hypertension. CONCLUSIONS: A limited number of studies suggest that higher IL-6, but not IL-1ß, might be associated with the development of hypertension.

Beneficial Effects of Astragalus membranaceus (Fisch.) Bunge Extract in Controlling Inflammatory Response and Preventing Asthma Features.

Astragalus membranaceus (Fisch.) Bunge root is used as herbal medicine for its immunomodulating activities in Chinese medicine. Recently, beneficial properties of A. membranaceus on allergic diseases have been proposed. Here we investigated the role of a commercial extract of A. membranaceus, standardized to 16% polysaccharides, in regulating the immune-inflammatory response in vitro and in vivo and its therapeutic application in asthma. A. membranaceus extract inhibited prostaglandin E2 and leukotriene C4 production in stimulated J774 and peritoneal macrophages, respectively. The extract also reduced interlukin-1ß, tumor necrosis factor-α, and nitrite production, affecting inducible nitric oxide synthase expression. In vivo experiments confirmed the anti-inflammatory properties of A. membranaceus, as evident by a reduction in zymosan-induced peritoneal cellular infiltration and pro-inflammatory mediator production. The efficacy of A. membranaceus extract in modulating the immune response was confirmed in a model of allergic airway inflammation. Extracts improve lung function by inhibiting airway hyperresponsiveness, airway remodeling, and fibrosis. Its anti-asthmatic effects were further sustained by inhibition of the sensitization process, as indicated by a reduction of ovalbumin-induced IgE levels and the mounting of a Th2 immune response. In conclusion, our data demonstrate the anti-inflammatory properties of the commercial extract of A. membranaceus and its beneficial effects on asthma feature development.

A vitamin E long-chain metabolite and the inspired drug candidate α-amplexichromanol relieve asthma features in an experimental model of allergen sensitization.

Benefits for vitamin E intake in diseases with inflammatory components have been described and related in part, to endogenously formed metabolites (long-chain metabolites, LCM). Here, we have evaluated the role of LCM in relieving asthma features. To this aim, the endogenous vitamin E metabolite α-13'-carboxychromanol (α-T-13'-COOH) that acts as potent 5-lipoxygenase inhibitor has been administered either intraperitoneally or by oral gavage to BALB/c mice sensitized by subcutaneous injection of ovalbumin (OVA). We also have taken advantage of the metabolically stable α-T-13'-COOH derivative α-amplexichromanol (α-AC). Intraperitoneal treatment with α-T-13'-COOH reduced OVA-induced airway hyperreactivity (AHR) as well as peri-bronchial inflammatory cell infiltration. α-AC was more efficacious than α-T-13'-COOH, as demonstrated by better control of AHR and in reducing subepithelial. Both compounds exerted their protective function by reducing pulmonary leukotriene C4 levels. Beneficial effects of α-AC were coupled to inhibition of the sensitization process, as indicated by a reduction of IgE plasma levels, lung mast cell infiltration and Th2 immune response. Metabololipidomics analysis revealed that α-AC raises the pulmonary levels of prostanoids, their degradation products, and 12/15-lipoxygenase metabolites. Following oral administration, the pharmacodynamically different profile in α-T-13'-COOH and α-AC was abrogated as demonstrated by a similar and improved efficacy in controlling asthma features as well as by metabololipidomics analysis. In conclusion, this study highlights a role for LCM and of vitamin E derivatives as pharmacologically active compounds that ameliorate asthmatic features and defines an important role for endogenous vitamin E metabolites in regulating immune response underlying the sensitization process.

Lack of Ecto-5'-Nucleotidase Protects Sensitized Mice against Allergen Challenge.

Ecto-5'-nucleotidase (CD73), the ectoenzyme that together with CD39 is responsible for extracellular ATP hydrolysis and adenosine accumulation, regulates immune/inflammatory processes by controlling innate and acquired immunity cell functions. We previously demonstrated that CD73 is required for the assessment of a controlled allergic sensitization, in mice. Here, we evaluated the response to aerosolized allergen of female-sensitized mice lacking CD73 in comparison with their wild type counterpart. Results obtained show, in mice lacking CD73, the absence of airway hyperreactivity in response to an allergen challenge, paralleled by reduced airway CD23+B cells and IL4+T cells pulmonary accumulation together with reduced mast cells accumulation and degranulation. Our findings indicate CD73 as a potential therapeutic target for allergic asthma.

Systemic administration of glucocorticoids, cardiovascular complications and mortality in patients hospitalised with COVID-19, SARS, MERS or influenza: A systematic review and meta-analysis of randomised trials.

BACKGROUND: Administration of glucocorticoids might reduce mortality in patients with severe COVID-19 but have adverse cardiometabolic effects. OBJECTIVES: to investigate the effect of systemic administration of glucocorticoids on cardiovascular complications and all-cause mortality in patients hospitalised with respiratory viral infections, including COVID-19, SARS, MERS and influenza. METHODS: We identified randomised trials published prior to July 28th, 2021. The Mantel-Haenszel random effects method and the Hartung and Knapp adjustment were used to obtain pooled estimates of treatment effect with 95% confidence intervals. RESULTS: No randomised trials of glucocorticoids for SARS, MERS or influenza reported relevant outcomes. We included eleven COVID-19 randomised trials (8109 patients). Overall, compared to placebo or standard care, glucocorticoids were not associated with a reduction of in-hospital mortality (p = 0.09). In a pre-specified sub-analysis, in-hospital mortality was reduced by 19% when follow-up was restricted to 14 days from randomisation (5/11 trials, 1329 patients, p = 0.02). With longer follow-up (9/11 trials, 7874 patients), administration of glucocorticoids was associated with a trend to benefit for those requiring mechanical ventilation (RR 0.86; 95% CI 0.57-1.27) but possible harm for those not receiving oxygen at randomisation (RR 1.27; 95% CI 1.00 - 1.61), an effect that was significantly different amongst subgroups (p = 0.0359). Glucocorticoids reduced the risk of worsening renal function by 37% (4/11 trials); reported rate of other cardiovascular complications was low. CONCLUSIONS: Administration of systemic glucocorticoids to patients hospitalised with COVID-19 does not lower mortality overall but may reduce it in those requiring respiratory support and increase it in those who do not.

Sex Hormone-Dependent Lipid Mediator Formation in Male and Female Mice During Peritonitis.

Introduction: Sex differences in inflammation are obvious and contribute to divergences in the incidence and severity of inflammation-related diseases that frequently preponderate in women. Lipid mediators (LMs), mainly produced by lipoxygenase (LOX) and cyclooxygenase (COX) pathways from polyunsaturated fatty acids (PUFAs), regulate all stages of inflammation. Experimental and clinical studies revealed sex divergences for selected LM pathways without covering the entire LM spectrum, and only few studies have addressed the respective role of sex hormones. Here, we performed the comprehensive LM profile analysis with inflammatory peritoneal exudates and plasma from male and female mice in zymosan-induced peritonitis to identify the potential sex differences in LM biosynthesis during the inflammatory response. We also addressed the impact of sex hormones by employing gonadectomy. Methods: Adult male and female CD1 mice received intraperitoneal injection of zymosan to induce peritonitis, a well-established experimental model of acute, self-resolving inflammation. Mice were gonadectomized 5 weeks prior to peritonitis induction. Peritoneal exudates and plasma were taken at 4 (peak of inflammation) and 24 h (onset of resolution) post zymosan and subjected to UPLC-MS-MS-based LM signature profiling; exudates were analyzed for LM biosynthetic proteins by Western blot; and plasma was analyzed for cytokines by ELISA. Results: Pro-inflammatory COX and 5-LOX products predominated in the peritoneum of males at 4 and 24 h post-zymosan, respectively, with slightly higher 12/15-LOX products in males after 24 h. Amounts of COX-2, 5-LOX/FLAP, and 15-LOX-1 were similar in exudates of males and females. In plasma of males, only moderate elevation of these LMs was apparent. At 4 h post-zymosan, gonadectomy strongly elevated 12/15-LOX products in the exudates of males, while in females, free PUFA and LOX products were rather impaired. In plasma, gonadectomy impaired most LMs in both sexes at 4 h with rather up-regulatory effects at 24 h. Finally, elevated 15-LOX-1 protein was evident in exudates of males at 24 h which was impaired by orchiectomy without the striking impact of gonadectomy on other enzymes in both sexes. Conclusions: Our results reveal obvious sex differences and roles of sex hormones in LM biosynthetic networks in acute self-resolving inflammation in mice, with several preponderances in males that appear under the control of androgens.

Exacerbation of Allergic Airway Inflammation in Mice Lacking ECTO-5'-Nucleotidase (CD73).

The airways are a target tissue of type I allergies and atopy is the main etiological factor of bronchial asthma. A predisposition to allergy and individual response to allergens are dependent upon environmental and host factors. Early studies performed to clarify the role of extracellular adenosine in the airways highlighted the importance of adenosine-generating enzymes CD73, together with CD39, as an innate protection system against lung injury. In experimental animals, deletion of CD73 has been associated with immune and autoimmune diseases. Our experiments have been performed to investigate the role of CD73 in the assessment of allergic airway inflammation following sensitization. We found that in CD73-/- mice sensitization, induced by subcutaneous ovalbumin (OVA) administration, increased signs of airway inflammation and atopy developed, characterized by high IgE plasma levels and increased pulmonary cytokines, reduced frequency of lung CD4+CD25+Foxp3+ T cells, but without bronchial hyperreactivity, compared to sensitized wild type mice. Our results provide evidence that the lack of CD73 causes an uncontrolled allergic sensitization, suggesting that CD73 is a key molecule at the interface between innate and adaptive immune response. The knowledge of host immune factors controlling allergic sensitization is of crucial importance and might help to find preventive interventions that could act before an allergy develops.

Staphylococcus aureus-Derived α-Hemolysin Evokes Generation of Specialized Pro-resolving Mediators Promoting Inflammation Resolution.

Underlying mechanisms of how infectious inflammation is resolved by the host are incompletely understood. One hallmark of inflammation resolution is the activation of specialized pro-resolving mediators (SPMs) that enhance bacterial clearance and promote tissue repair. Here, we reveal α-hemolysin (Hla) from Staphylococcus aureus as a potent elicitor of SPM biosynthesis in human M2-like macrophages and in the mouse peritoneum through selective activation of host 15-lipoxygenase-1 (15-LOX-1). S. aureus-induced SPM formation in M2 is abolished upon Hla depletion or 15-LOX-1 knockdown. Isolated Hla elicits SPM formation in M2 that is reverted by inhibition of the Hla receptor ADAM10. Lipid mediators derived from Hla-treated M2 accelerate planarian tissue regeneration. Hla but not zymosan provokes substantial SPM formation in the mouse peritoneum, devoid of leukocyte infiltration and pro-inflammatory cytokine secretion. Besides harming the host, Hla may also exert beneficial functions by stimulating SPM production to promote the resolution of infectious inflammation.

5α-dihydrotestosterone abrogates sex bias in asthma like features in the mouse.

Androgen levels inversely correlate with the incidence, susceptibility and severity of asthma. However, whether male sex hormones such as 5α-dihydrotestosterone (DHT) have beneficial effects on asthma symptoms and/or could affect asthma susceptibility have not been investigated. DHT administration to female mice, during the sensitization phase, abrogates the sex bias in bronchial hyperreactivity. This effect correlates with inhibition of leukotriene biosynthesis in the lung. DHT significantly inhibits also other asthma-like features such as airway hyperplasia and mucus production in sensitized female mice. Conversely, DHT does not affect plasma IgE levels as well as CD3+CD4+ IL-4+ cell and IgE+c-Kit+ cell infiltration within the lung but prevents pulmonary mast cell activation. The in vitro study on RBL-2H3 cells confirms that DHT inhibits mast cell degranulation. In conclusion, our data demonstrate that immunomodulatory effects of DHT on mast cell activation prevent the translation of allergen sensitization into clinical manifestation of asthma.

The Ecto-5'-Nucleotidase/CD73 Inhibitor, α,ß-Methylene Adenosine 5'-Diphosphate, Exacerbates Carrageenan-Induced Pleurisy in Rat.

The ecto-5'-nucleotidase (ecto-5'NT/CD73) represents a crucial enzyme for endogenous adenosine generation. Several findings have shown that CD73 plays an important role in regulating vascular permeability and immune cell function. Adenosine 5'-(α,ß-methylene)diphosphate (APCP) is a CD73 inhibitor, widely used as pharmacological tool to investigate the role of CD73/adenosine pathway in several in vitro and in vivo models, although it has been also shown to inhibit other ectoenzymes involved in adenosinergic pathway. Here, we evaluated the effect of APCP in the development of inflammation in carrageenan-induced pleurisy model. We found that treatment with APCP (400 µg/rat) significantly increased cell accumulation, exudate formation, and pro-inflammatory cytokine content into the pleural cavity in the acute phase (4 h) of inflammation, with no differences in the sub-acute phase (72 h) except for the regulation of monocyte chemotactic protein-1 levels. In addition, cells collected by pleural lavage fluids of APCP-treated rats, 4 h following carrageenan injection, showed increased ability to migrate in vitro, both in presence and in absence of N-formyl-L-methionyl-L-leucyl-L-phenylalanine as chemotactic stimulus, compared to cells obtained by control rats. Our results demonstrate that APCP exacerbates the early phase of carrageenan-induced pleurisy by controlling pleural effusion and polymorphonuclear migration in vivo and ex vivo. This effect is likely dependent upon CD73 inhibition, although an inhibitory effect of other ectoenzymes cannot be ruled out.

Novel benzoxanthene lignans that favorably modulate lipid mediator biosynthesis: A promising pharmacological strategy for anti-inflammatory therapy.

Lipid mediators (LM) encompass pro-inflammatory prostaglandins (PG) and leukotrienes (LT) but also specialized pro-resolving mediators (SPM) which display pivotal bioactivities in health and disease. Pharmacological intervention with inflammatory disorders such as osteoarthritis and rheumatoid arthritis commonly employs anti-inflammatory drugs that can suppress PG and LT formation, which however, possess limited effectiveness and side effects. Here, we report on the discovery and characterization of the two novel benzoxanthene lignans 1 and 2 that modulate select LM biosynthetic enzymes enabling the switch from pro-inflammatory LT to SPM biosynthesis as potential pharmacological strategy to intervene with inflammation. In cell-free assays, compound 1 and 2 inhibit microsomal prostaglandin E2 synthase-1 and leukotriene C4 synthase (IC50 ∼ 0.6-3.4 µM) and potently interfere with 5-lipoxygenase (5-LOX), the key enzyme in LT biosynthesis (IC50 = 0.04 and 0.09 µM). In human neutrophils, monocytes and M1 and M2 macrophages, compound 1 and 2 efficiently suppress LT biosynthesis (IC50 < 1 µM), accompanied by elevation of 15-LOX-derived LM including SPM. In zymosan-induced murine peritonitis, compound 1 and 2 ameliorated self-limited inflammation along with suppression of early LT formation and elevation of subsequent SPM biosynthesis in vivo. Together, these novel benzoxanthene lignans promote the LM class switch from pro-inflammatory towards pro-resolving LM to terminate inflammation, suggesting their suitability as novel leads for pharmacotherapy of arthritis and related inflammatory disorders.

The relatively selective cyclooxygenase-2 inhibitor nimesulide: What's going on?

Nimesulide is a relatively selective cyclooxygenase (COX)-2 inhibitor, non-steroidal anti-inflammatory drug; it has been discovered in 1971 and firstly commercialized in Italy in 1985. There is much evidence that the pharmacological profile of nimesulide is peculiar and not shared with the other COX-2 selective inhibitors, suggesting that other molecular mechanisms besides inhibition of COX-2 derived prostaglandins are involved. Similarly, experimental data suggest that the gastrointestinal safety of nimesulide cannot be ascribed only to a COX-1 sparing effect. On the inflammatory process, the efficacy of nimesulide is dependent upon a wide spectrum of actions, due to the combination of effects on immune and non-immune cells. Early data demonstrated a central role for cyclic AMP (cAMP) in the anti-inflammatory effect of nimesulide; more recently, we have shown the involvement of the pathway ecto-5'-nucleotidase/adenosine A2A receptor. To date, the molecular mechanism(s) that confers uniqueness to nimesulide have not yet been defined. To go inside the mechanism of action of an existing drug, such as nimesulide, would be helpful to refine its therapeutic use but also to identify new targets for novel therapeutic anti-inflammatory approach. Here, we focus on accumulated evidence for a peculiar pharmacological profile of nimesulide.

Ectonucleoside Triphosphate Diphosphohydrolase-1/CD39 Affects the Response to ADP of Female Rat Platelets.

There is evidence that an imbalance of extracellular purine levels may be associated with increased cardiovascular risk. Platelets play a pivotal role in vascular homeostasis and thrombosis and are important source of purine nucleotides and nucleosides. Hydrolysis of nucleotides ATP and ADP is regulated by two ectonucleotidases, triphosphate diphosphohydrolase-1 (NTPDase-1/CD39) and ecto-5'-nucleotidase (ecto-5'-NT/CD73). CD39 enzyme is expressed on the endothelium, circulating blood cells, and smooth muscle cells; there is evidence that changes in CD39 expression and activity affects the potential thrombogenic of a tissue. Gender difference in the cardiovascular risk has been extensively observed; however, while the age-dependent difference in the prevalence of cardiovascular events between men and women has been attributed to the loss of the protective effect of estrogens in the postmenopausal period, the physiological mechanism behind gender disparity is still unclear. Here, we evaluated comparatively male and female rat platelet reactivity and considered the possible role of CD39 at the basis of difference observed. We found a reduced in vitro response to ADP (1-30 µM) of female compared to male platelets, associated to increased platelet CD39 expression and activity. Platelet response to ADP was strongly increased by incubation (10 min) with the CD39 inhibitor, ARL67156 (100 µM), while male platelet response was unaffected. Rat treatment with clopidogrel (30 mg/kg, per os) inhibited ex vivo platelet aggregation. Bleeding time was prolonged in female compared to male. Taken together, our results suggest that platelet ATPase and ADPase activity might be a reliable predictor of platelet reactivity.

Adenosine A2A Receptor Agonist, 2-p-(2-Carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine Hydrochloride Hydrate, Inhibits Inflammation and Increases Fibroblast Growth Factor-2 Tissue Expression in Carrageenan-Induced Rat Paw Edema.

Adenosine is the final product of ATP metabolism, mainly derived from the action of 5'-nucleotidase cleavage of AMP. Cellular production of adenosine is greatly enhanced in inflamed tissues, ischemic tissues, and under hypoxia, where ATP is released from damaged cells. Much evidence has been accumulated on adenosine anti-inflammatory effects mediated through A2A receptor activation; A2A adenosine receptor has also been shown to play a role in matrix deposition and wound healing in a damaged tissue, contributing to dermal tissue protection and repair. Fibroblast growth factor-2 (FGF-2) is a powerful mitogen for fibroblast; it is expressed by several inflammatory cell types and plays a pivotal role in angiogenesis, wound healing, gastric ulcer protection. Human recombinant FGF-2 has been shown to have anti-inflammatory effects. The purpose of the present work was to investigate on the anti-inflammatory effect of systemic administration of the adenosine A2A agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride hydrate (CGS21680) in the rat model of carrageenan-induced paw edema. We found that CGS21680 inhibits inflammation induced by carrageenan injection into the rat paw, and this effect is associated to the local reduction of cytokine levels and dermal increase of FGF-2 expression. Our results suggest that FGF-2 might be involved in the anti-inflammatory and tissue protective effect due to A2A receptor activation.

Palmitoylethanolamide Supplementation during Sensitization Prevents Airway Allergic Symptoms in the Mouse.

One important risk factor for the development of asthma is allergen sensitization. Recent increasing evidence suggests a prominent role of mast cells in asthma pathophysiology. Since Palmitoylethanolamide (PEA), an endogenous lipid mediator chemically related to - and co-released with- the endocannabinoid anandamide, behaves as a local autacoid down-regulator of mast cell activation and inflammation, we explored the possible contribution of PEA in allergic sensitization, by using ovalbumin (OVA) as sensitizing agent in the mouse. PEA levels were dramatically reduced in the bronchi of OVA-treated animals. This effect was coupled to a significant up-regulation of CB2 and GPR55 receptors, two of the proposed molecular PEA targets, in bronchi harvested from allergen-sensitized mice. PEA supplementation (10 mg/kg, 15 min before each allergen exposure) prevented OVA-induced bronchial hyperreactivity, but it did not affect IgE plasma increase. On the other hand, PEA abrogated allergen-induced cell recruitment as well as pulmonary inflammation. Evaluation of pulmonary sections evidenced a significant inhibitory action of PEA on pulmonary mast cell recruitment and degranulation, an effect coupled to a reduction of leukotriene C4 production. These findings demonstrate that allergen sensitization negatively affects PEA bronchial levels and suggest that its supplementation has the potential to prevent the development of asthma-like features.

Red Wine Inhibits Aggregation and Increases ATP-diphosphohydrolase (CD39) Activity of Rat Platelets in Vitro.

Moderate consumption of red wine has been shown to exert a peculiar cardioprotective effect compared with other alcoholic beverages; inhibition of platelet aggregation seems to be one of the mechanisms underlying this beneficial effect. CD39/ATP-diphosphohydrolase is an integral membrane glycoprotein metabolizing ATP and ADP to AMP; in concert with CD73/ecto-5'-nucleotidase, it contributes to extracellular adenosine accumulation. CD39 is considered a key modulator of thrombus formation; it inhibits platelet aggregation by promoting ADP hydrolysis. There is evidence that red wine consumption increases CD39 activity in platelets from streptozotocin-induced diabetic rats. Here we show that two kinds of Aglianico red wines inhibit aggregation and increase ATP--and ADPase activity in rat platelets.

Adenosine signalling mediates the anti-inflammatory effects of the COX-2 inhibitor nimesulide.

Extracellular adenosine formation from ATP is controlled by ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase/CD39) and ecto-5'-nucleotidase (e-5NT/CD73); the latter converts AMP to adenosine and inorganic phosphate, representing the rate limiting step controlling the ratio between extracellular ATP and adenosine. Evidence that cellular expression and activity of CD39 and CD73 may be subject to changes under pathophysiological conditions has identified this pathway as an endogenous modulator in several diseases and was shown to be involved in the molecular mechanism of drugs, such as methotrexate, salicylates , interferon-ß. We evaluated whether CD73/adenosine/A2A signalling pathway is involved in nimesulide anti-inflammatory effect, in vivo and in vitro. We found that the adenosine A2A agonist, 4-[2-[[6-amino-9-(N-ethyl-ß-d-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS21680, 2mg/kg ip.), inhibited carrageenan-induced rat paw oedema and the effect was reversed by co-administration of the A2A antagonist -(2-[7-amino-2-[2-furyl][1,2,4]triazolo[2,3-a][1,3,5]triazin-5-yl-amino]ethyl)phenol (ZM241385; 3mg/kg i.p.). Nimesulide (5mg/kg i.p.) anti-inflammatory effect was inhibited by pre-treatment with ZM241385 (3mg/kg i.p.) and by local administration of the CD73 inhibitor, adenosine 5'-(α,ß-methylene)diphosphate (APCP; 400µg/paw). Furthermore, we found increased activity of 5'-nucleotidase/CD73 in paws and plasma of nimesulide treated rats, 4h following oedema induction. In vitro, the inhibitory effect of nimesulide on nitrite and prostaglandin E2 production by lipopolysaccharide-activated J774 cell line was reversed by ZM241385 and APCP. Furthermore, nimesulide increased CD73 activity in J774 macrophages while it did not inhibit nitrite accumulation by lipopolysaccharide-activated SiRNA CD73 silenced J774 macrophages. Our data demonstrate that the anti-inflammatory effect of nimesulide in part is mediated by CD73-derived adenosine acting on A2A receptors.

Salvinorin A Inhibits Airway Hyperreactivity Induced by Ovalbumin Sensitization.

Salvinorin A, a neoclerodane diterpene isolated from Salvia divinorum, exerts a number of pharmacological actions which are not solely limited to the central nervous system. Recently it has been demonstrated that Salvinorin A inhibits acute inflammatory response affecting leukotriene (LT) production. Since LTs are potent lipid mediators implicated in allergic diseases, we evaluated the effect of Salvinorin A on allergic inflammation and on airways following sensitization in the mouse. Mice were sensitized with s.c. injection of ovalbumin (OVA) on days 1 and 8. Sensitized mice received on days 9 and 12 on the shaved dorsal surface air administration to induce the development of the air-pouches. On day 15 animals were challenged by injection of OVA into the air-pouch. Salvinorin A, administered (10 mg/kg) before each allergen exposure, significantly reduced OVA-induced LT increase in the air pouch. This effect was coupled to a reduction in cell recruitment and Th2 cytokine production. In another set of experiments, mice were sensitized with OVA and both bronchial reactivity and pulmonary inflammation were assessed. Salvinorin A abrogated bronchial hyperreactivity and interleukin (IL)-13 production, without effect on pulmonary inflammation. Indeed cell infiltration and peribronchial edema were still present following diterpenoid treatment. Similarly, pulmonary IL-4 and plasmatic IgE levels were not modulated. Conversely, Salvinorin A significantly reduced LTC4 production in the lung of sensitized mice. Finally mast cell activity was evaluated by means of toluidine blue staining. Data obtained evidenced that Salvinorin A significantly inhibited mast cell degranulation in the lung. Our study demonstrates that Salvinorin A inhibits airway hyperreactivity induced by sensitization by inhibition of LT production and mast cell degranulation. In conclusion Salvinorin A could represent a promising candidate for drug development in allergic diseases such as asthma.