Monosodium urate crystal interleukin-1β release is dependent on Toll-like receptor 4 and transient receptor potential V1 activation

OBJECTIVE

The present study aimed to elucidate the mechanisms involved in MSU-induced IL-1β release in a rodent animal model of acute gout arthritis.

METHODS

Painful (mechanical and thermal hypersensitivity, ongoing pain and arthritis score) and inflammatory (oedema, plasma extravasation, cell infiltration and IL-1β release) parameters were assessed several hours after intra-articular injection of MSU (100 µg/articulation) in wild-type or knockout mice for Toll-like receptor 4 (TLR4), inducible nitric oxide synthase (iNOS), transient receptor potential (TRP) V1 and the IL-1 receptor (IL-1R). Also, wild-type animals were treated with clodronate, lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS) (TLR4 antagonist), spleen tyrosine kinase (SYK) inhibitor (iSYK), aminoguanidine (AMG, an iNOS inhibitor) or SB366791 (TRPV1 antagonist). Nitrite/nitrate and IL-1β levels were measured on the synovial fluid of wild-type mice, 2 h after intra-articular MSU injections, or medium from macrophages stimulated for MSU (1000 μg) for 2 h.

RESULTS

Intra-articular MSU injection caused robust nociception and severe inflammation from 2 up to 6 h after injection, which were prevented by the pre-treatment with clodronate, LPS-RS, iSYK, AMG and SB366791, or the genetic ablation of TLR4, iNOS, TRPV1 or IL-1R. MSU also increased nitrite/nitrate and IL-1β levels in the synovial fluid, which was prevented by clodronate, LPS-RS, iSYK and AMG, but not by SB366791. Similarly, MSU-stimulated peritoneal macrophages released nitric oxide, which was prevented by LPS-RS, iSYK and AMG, but not by SB366791, and released IL-1β, which was prevented by LPS-RS, iSYK, AMG and SB366791.

CONCLUSION

Our data indicate that MSU may activate TLR4, SYK, iNOS and TRPV1 to induce the release of IL-1β by macrophages, triggering nociception and inflammation during acute gout attack.

Correction to: The effect of beta blocker withdrawal on adenosine myocardial perfusion imaging

Regrettably the original version of the above article contained errors in Table 2 and wrong values in the text. The corrected table is presented here and the values which have been corrected now appear in bold text. Page 1223 abstract Global MBF showed an increase from 180.2 ± 59.9 to 193.6 ± 60.8 mL minute/100 g (P = .002) after beta blocker withdrawal. Page 1225 Mean systolic and mean diastolic blood pressure during adenosine were nearly identical (P = .77 and P = .79) with and without beta blocker. Mean heart rate and mean RPP during adenosine significantly increased after beta blocker withdrawal by 15.2% ± 17% (P = .001) and 16.2% ± 23% (P = .004), respectively. Page 1226 The data are listed in Table 2, lower third. Global MBF showed a significant increase by 7.4% ± 10% (P = .002) after beta blocker withdrawal. The individual data are depicted in Figure 1. All but three patients had a lower global MBF without beta blocker than with. The segmental MBF values (Figure 2) demonstrated a strong correlation over the entire range of perfusion values. The average effect was a slight perfusion shift of about 1015 mL minute-1/100 g in the range of 100-300 mL minute-1/100 g. The mCR under adenosine declined by 8.1%  ± 11% (P = .038) and the normalized RPP by 16.2% ± 21% (P = .004) after betablocker discontinuation. Table 2 Hemodynamic response under adenosine, perfusion, and left-ventricular function.

The effect of beta blocker withdrawal on adenosine myocardial perfusion imaging

BACKGROUND

The effect of beta blockers on myocardial blood flow (MBF) under vasodilators has been studied in several SPECT and PET myocardial perfusion imaging (MPI) studies with divergent results. The present study evaluated the effect of a beta blocker withdrawal on quantitative adenosine MBF and on MPI results.

METHODS

Twenty patients with beta blockers and CAD history were studied with quantitative adenosine N-13 ammonia PET. The first study was performed under complete medication and the second after beta blocker withdrawal. The PET studies were independently read with respect to MPI result and clinical decision making.

RESULTS

Global MBF showed an increase from 180.2 ± 59.9 to 193.6 ± 60.8 mL·minute(-1)/100 g (P = .02) after beta blocker withdrawal. The segmental perfusion values were closely correlated (R(2) = 0.82) over the entire range of perfusion values. An essentially different interpretation after beta blocker discontinuation was found in two cases (10%).

CONCLUSION

A beta blocker withdrawal induces an increase in adenosine MBF. In the majority of cases, MPI interpretation and decision making are independent of beta blocker intake. If a temporary beta blocker withdrawal before MPI is not possible or was not realized by the patient, it is appropriate to perform adenosine stress testing without loss of the essential MPI result.

The role of kinin B1 receptor and the effect of angiotensin I-converting enzyme inhibition on acute gout attacks in rodents

OBJECTIVE

Verify the role of the kinin B1 receptors (B1R) and the effect of ACE inhibitors (ACEi) on acute gout induced by monosodium urate (MSU) crystals in rodents.

METHODS

Painful (overt pain and allodynia) and inflammatory parameters (joint oedema, leukocyte trafficking, interleukin-1β levels) of acute gout attacks were assessed several hours after an intra-articular injection of MSU (1.25 or 0.5 mg/articulation) into the ankle of rats or mice, respectively. The role of B1R was investigated using pharmacological antagonism or gene deletion. Additionally, B1R immunoreactivity in ankle tissue and sensory neurons, kininase I activity and des-Arg(9)-bradykinin synovial levels were also measured. Similar tools were used to investigate the effects of ACEi on a low dose of MSU (0.0125 mg/articulation)-induced inflammation.

RESULTS

Kinin B1R antagonism or gene deletion largely reduced all painful and inflammatory signs of gout. Furthermore, MSU increased B1R expression in articular tissues, the content of the B1 agonist des-Arg(9)-bradykinin and the activity of the B1 agonist-forming enzyme kininase I. A low dose of MSU crystals, which did not induce inflammation in control animals, caused signs of acute gout attacks in ACEi-treated animals that were B1R-dependent.

CONCLUSIONS

Kinin B1R contributes to acute gouty attacks, including the ones facilitated by ACEi. Therefore, B1R is a potential therapeutic target for the treatment and prophylaxis of gout, especially in patients taking ACEi.

TRPA1 receptor stimulation by hydrogen peroxide is critical to trigger hyperalgesia and inflammation in a model of acute gout

Acute gout attacks produce severe joint pain and inflammation associated with monosodium urate (MSU) crystals leading to oxidative stress production. The transient potential receptor ankyrin 1 (TRPA1) is expressed by a subpopulation of peptidergic nociceptors and, via its activation by endogenous reactive oxygen species, including hydrogen peroxide (H2O2), contributes to pain and neurogenic inflammation. The aim of this study was to investigate the role of TRPA1 in hyperalgesia and inflammation in a model of acute gout attack in rodents. Inflammatory parameters and mechanical hyperalgesia were measured in male Wistar rats and in wild-type (Trpa1(+/+)) or TRPA1-deficient (Trpa1(-/-)) male mice. Animals received intra-articular (ia, ankle) injection of MSU. The role of TRPA1 was assessed by receptor antagonism, gene deletion or expression, sensory fiber defunctionalization, and calcitonin gene-related peptide (CGRP) release. We found that nociceptor defunctionalization, TRPA1 antagonist treatment (via ia or oral administration), and Trpa1 gene ablation abated hyperalgesia and inflammatory responses (edema, H2O2 generation, interleukin-1β release, and neutrophil infiltration) induced by ia MSU injection. In addition, we showed that MSU evoked generation of H2O2 in synovial tissue, which stimulated TRPA1 producing CGRP release and plasma protein extravasation. The MSU-elicited responses were also reduced by the H2O2-detoxifying enzyme catalase and the reducing agent dithiothreitol. TRPA1 activation by MSU challenge-generated H2O2 mediates the entire inflammatory response in an acute gout attack rodent model, thus strengthening the role of the TRPA1 receptor and H2O2 production as potential targets for treatment of acute gout attacks.

Antinociceptive and antiedematogenic effect of pecan (Carya illinoensis) nut shell extract in mice: a possible beneficial use for a by-product of the nut industry

Abstract Background: Interest in pecan (Carya illinoensis) nut shells, a by-product of the nut industry, has increased due to its anti-inflammatory and antioxidant activities. The goal of this study was to evaluate the antinociceptive and antiedematogenic activity and the mechanisms of the pecan shell aqueous extract (AE). Methods: First, we performed fingerprinting of C. illinoensis AE. The antinociceptive and antiedematogenic effects of AE intragastric (i.g.) administration in mice (male Swiss mice 20-30 g) were evaluated using the acetic acid test or after subcutaneous (s.c.) paw injection of diverse transient receptor potential ankyrin 1 (TRPA1) agonists, including hydrogen peroxide (H2O2), allyl isothiocyanate, or cinnamaldehyde. We also observed AE antinociceptive and antiedematogenic effects after carrageenan s.c. paw injection and measured H2O2 production. Moreover, we observed the development of adverse effects after AE i.g. treatment. Results: The high-performance liquid chromatography fingerprinting of AE showed the presence of rutin. AE or rutin i.g. treatment produced antinociception in the acetic acid test and reduced the nociception and edema mediated by H2O2 s.c. hind paw injection or nociception induced by other TRPA1 agonists. Moreover, AE or rutin reduced the hyperalgesia, edema, and H2O2 production induced by carrageenan s.c. paw injection. No motor, gastric, or toxicological alterations were observed after AE administration. Conclusions: Collectively, the present results show that AE and its constituent rutin produced antinociceptive and antiedematogenic action in models of acute and persistent inflammatory nociception and it seems to be related to the inhibition of TRPA1 receptor activation.

Antiinflammatory effects of Viola tricolor gel in a model of sunburn in rats and the gel stability study

ETHNOPHARMACOLOGICAL RELEVANCE

Viola tricolor, popularly known as heartsease has been empirically used in several skin disorders, including burns.

AIM OF THE STUDY

The objective of this study was investigate the antinociceptive and antiinflammatory effect of a gel containing extract of Viola tricolor flowers on thermal burn induced by UVB irradiation and to perform gel stability study.

METHODS

The antinociceptive and antiinflammatory effect were evaluated by static and dynamic mechanical allodynia model, paw edema, and neutrophilic cell infiltration. Metabolites compounds were quantified by HPLC. The gel stability study was performed analyzing organoleptical aspects, besides pH, viscosity, and quantification of rutin by HPLC.

RESULTS

In the results were evidenced changes in threshold in statical and dynamic mechanical allodynia (I(max)=100 ± 10% and 49 ± 10%, respectively), paw edema (I(max)=61 ± 6%), and myeloperoxidase activity (I(max)=89 ± 5%). Such effects may be attributed, in part, to rutin, salicylic and chlorogenic acids, and others compounds found in this species. No important changes were detected in the stability study, in all aspects analyzed in temperature below 25 °C.

CONCLUSION

These findings suggest that Viola tricolor gel has an antinociceptive and antiinflammatory effect in the ultraviolet-B-induced burn, since maintain the temperature below 25 °C.

Anti-nociceptive and anti-edematogenic effects of glibenclamide in a model of acute gouty attack in rats

OBJECTIVE AND DESIGN

We investigated the effect of glibenclamide on inflammatory parameters in a model of acute gouty attack in rats.

TREATMENT

Intra-articular injection of 50 μl of monosodium urate (MSU) crystals (1.25 mg/site) was used to induce gout-related inflammation. The effects of glibenclamide (1-10 mg/kg, s.c.) or dexamethasone (8 mg/kg, s.c., positive control) were assessed on several inflammation parameters.

METHODS

Spontaneous nociception assessment, edema measurement, total and differential leucocyte counts, interleukin (IL)-1β release, prostaglandin E2 production and determination of blood glucose levels were analyzed. Peritoneal macrophages were incubated with MSU and levels of IL-1β were measured. Statistical significance was assessed by one- or two-way analysis of variance.

RESULTS

Glibenclamide (3 mg/kg) or dexamethasone (8 mg/kg) prevented nociception and edema induced by MSU injection in rats. Glibenclamide did not affect leukocyte infiltration, IL-1β release and PGE2 production, but only reduced IL-1β production by MSU-stimulated macrophages at very high concentration (200 μM). Dexamethasone significantly reduced leukocyte infiltration, IL-1β release and PGE2 production. Glibenclamide reduced whereas dexamethasone increased blood glucose levels of MSU-injected rats.

CONCLUSIONS

Glibenclamide reduced nociception and edema, but not leukocyte infiltration, IL-1β release and PGE2 production. However, its substantial effect on nociception and edema suggests that glibenclamide can be an interesting option as an adjuvant treatment for pain induced by acute attacks of gout.

Glycaemic and insulinaemic response of Quarter Horses to concentrates high in fat and low in soluble carbohydrates

REASONS FOR PERFORMING STUDY

Quarter Horses are particularly susceptible to polysaccharide storage myopathy (PSSM). Nutritional therapy and possibly prophylaxis includes fat-supplemented diets whilst starch supply should be kept to a minimum.

OBJECTIVES

To investigate the glycaemic and insulinaemic response of clinically normal Quarter Horses to concentrates high in fat and low in starch.

METHODS

Twelve Quarter Horses were studied. The precondition for inclusion in the study population was that the horses had not shown clinical signs of myopathy. The Quarter Horses were fed according to a 4 x 4 Latin square design haylage plus isocaloric concentrates based on barley and oats as control (CO), sugar beet pulp, grass meal and soybean oil (SB), rice bran and grass meal (RB) and rice bran, grass meal, sugar beet pulp and soybean oil (CP), each over 2 weeks after 1 week of adaptation. At the end of each period, 1 kg of concentrate was fed and blood sampled 0, 30, 60, 90, 120, 180, 240, and 300 min post prandial (ppr.). Creatine kinase (CK; 0 min ppr. only), glucose and insulin were analysed. Glycaemic and insulinaemic index was calculated from each concentrates area under the curve (AUC) relative to CO.

RESULTS

Rice bran containing concentrates were partially refused at the beginning of the trial periods. CK activity, and glucose and insulin patterns (ppr. mean, peak, AUC, index) were highest with CO (P<0.05). The correlation between glucose and insulin (P<0.001) ranged from r = 0.570 (CO) to r = 0.364 (RB). Basal CK was highly correlated (P<0.001) to the mean ppr. plasma glucose.

CONCLUSION

Rice bran, sugar beet pulp, grass meal and soybean oil are suitable to include in concentrates that induce low glycaemic and insulinaemic response. Its acceptance seems to be a question of habituation. Although the mechanism is not completely understood, glucose patterns and basal CK activity are highly positively correlated. Both were affected by the type of concentrate used.

POTENTIAL RELEVANCE

Results support the suggestion that low-starch and high-fat feeding may be helpful not only in the nutrition of affected horses, but also to prevent future PSSM associated discomfort in particularly susceptible horses.

Dexamethasone-loaded nanoparticle-coated microparticles: Correlation between in vitro drug release and drug transport across Caco-2 cell monolayers

This work reports the preparation of dexamethasone in nanoparticle-coated microparticles and the study of the influence of such microencapsulation on drug absorption across Caco-2 cell monolayers. Nanoparticle-coated microparticles were prepared by spray-drying using nanocapsules (NC) or nanospheres (NS) in aqueous suspensions as coating material. Drug contents ranged from 64 to 134mgg(-1), yields between 49% and 67% and moisture content below 2.0%. SEM and AFM analysis demonstrated that the nanoparticle-coated microparticles (20-53microm) show nanostructures on their surface with a similar diameter compared to the aqueous suspensions. The type of nanocoating material had a significant influence on the drug release profile and on the drug permeation across Caco-2 cells: NC-coated microparticles led to a prolonged release and slower transport across Caco-2 cell monolayers, while the NS-coated microparticles showed a faster release and Caco-2 transport compared to uncoated microparticles. The correlation between the amount of drug permeated and the drug released (%) suggests that the drug absorption from such a delivery system is controlled mainly by the release rate rather than by epithelial permeability. Caco-2 transport studies appear to be a useful characterization tool for the development of microparticulate oral controlled release systems.

[Thoracic actinomycosis]

Thoracic actinomycosis was identified in a 14 year old girl. The disease is infrequent in children and diagnosis is difficult. The occurrence of a protracted pulmonary lesion, together with osteomyelitis of several ribs and by fistulae formation in the chest wall, with production of characteristic "sulfur granules", were the key elements to suspect the right diagnosis, which was confirmed by a bacteriological and histological studies. Treatment with high doses of intravenous penicillin, 3 million U four times a day for 4 weeks, followed by long term oral therapy with the same drug was done, with remission of pulmonary, osseous and cutaneous lesions.