Role of nitric oxide, bradykinin B2 receptor, and TRPV1 in the airway alterations caused by simvastatin in rats.

Dry cough has been reported in patients receiving statin therapy. However, the underlying mechanism or other possible alterations in the airways induced by statins remain unknown. Thus, the aim of this study was to evaluate whether simvastatin promotes alterations in airways, such as bronchoconstriction and plasma extravasation, as well as the mechanism involved in these events. Using methods to detect alterations in airway resistance and plasma extravasation, we demonstrated that simvastatin [20 mg/kg, intravenous (i.v.)] caused plasma extravasation in the trachea (79.8 + 14.8 µg/g/tissue) and bronchi (73.3 + 8.8 µg/g/tissue) of rats, compared to the vehicle (34.2 + 3.6 µg/g/tissue and 29.3 + 5.3 µg/g/tissue, respectively). NG-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg, intraperitoneal), a nitric oxide (NO) synthase inhibitor, Icatibant [HOE 140, 10 nmol/50 µl, intratracheal (i.t.)], a bradykinin B2 antagonist, and capsazepine (100 nmol/50 µl, i.t.), a TRPV1 antagonist, attenuated simvastatin-induced plasma extravasation. Simvastatin (5, 10 and 20 mg/kg) did not cause bronchoconstriction per se, but exacerbated the bronchoconstrictive response to bradykinin (30 nmol/kg, i.v.), a B2 agonist (0.7 + 0.1 ml/H2O), or capsaicin (30 nmol/kg, i.v.), a TRPV1 agonist (0.8 + 0.1 ml/H2O), compared to the vehicle (0.1 + 0.04 ml/H2O and 0.04 + 0.01 ml/H2O, respectively). The bronchoconstriction elicited by bradykinin (100 nmol/kg, i.v.) in simvastatin non-treated rats was inhibited by L-NAME. The exacerbation of bronchoconstriction induced by bradykinin or capsaicin in simvastatin-treated rats was inhibited by L-NAME, HOE 140 or capsazepine. These results suggest that treatment with simvastatin promotes the release of bradykinin, which, via B2 receptors, releases NO that can then activate the TRPV1 to promote plasma extravasation and bronchoconstriction.

Modeling Cost-Effectiveness of On-Demand Treatment for Hereditary Angioedema Attacks.

BACKGROUND: Hereditary angioedema (HAE) is a rare C1-inhibitor (C1-INH) deficiency disease. Low levels of functional C1-INH can lead to recurrent attacks of severe swelling occurring in areas such as the limbs, face, gastrointestinal tract, and throat. These attacks are both painful and disabling and, if not treated promptly and effectively, can result in hospitalization or death. Agents targeting the specific physiologic pathway of HAE attacks can offer improved outcomes with limited side effects compared with nonspecific therapies. However, these treatments display varying efficacy in HAE patients, including the need to redose or seek additional care if the treatment does not resolve symptoms effectively. OBJECTIVE: To analyze the expected cost and utility per HAE attack when treated on-demand with HAE therapies indicated for the treatment of acute attacks. METHODS: A decision-tree model was developed using TreeAge Pro software. Four on-demand HAE treatments were included: ecallantide, icatibant, plasma-derived (pd)C1-INH, and recombinant human (rh)C1-INH. The model uses probabilities for redosing, self-administration versus health care provider administration, and risk of hospitalization. Costs within the model consisted of the HAE treatments and associated health care system expenses. Nonattack baseline utility and attack utility were implemented for effectiveness calculations; time to attack resolution was considered as well. Effectiveness and overall costs per attack were calculated and used to estimate cost per quality-adjusted life-year (QALY). Variability and ranges in cost-effectiveness were determined using probabilistic sensitivity analyses. Finally, a budget impact model for a health plan with 1 million covered lives was also developed. RESULTS: The base case model outputs show costs and calculated effectiveness per attack at $12,905 and 0.806 for rhC1-INH, $14,806 and 0.765 for icatibant, $14,668 and 0.769 for pdC1-INH, and $21,068 and 0.792 for ecallantide, respectively. Cost per QALY was calculated using 26.9 attacks per person-year, leading to results of $420,941 for rhC1-INH, $488,349 for icatibant, $483,892 for pdC1-INH, and $689,773 for ecallantide. Sensitivity analyses demonstrate that redose rates (from 3% for rhC1-INH to 44% for icatibant) are a primary driver of variability in cost-effectiveness. Annual health plan costs from the budget impact model are calculated as $6.94 million for rhC1-INH, $7.97 million for icatibant, $7.90 million for pdC1-INH, and $11.33 million for ecallantide. CONCLUSIONS: Accounting for patient well-being and additional cost components of HAE attacks generates a better estimation of cost-effectiveness than drug cost alone. Results from this model indicate that rhC1-INH is the dominant treatment option with lower expected costs and higher calculated effectiveness than comparators. Further analyses reinforce the idea that low redose rates contribute to improved cost-effectiveness. DISCLOSURES: Funding support was contributed by Pharming Healthcare. Relan and Adams are employed by Pharming Healthcare. Tyson and Magar are employed by AHRM, which received fees to perform the analysis and develop the manuscript. Bernstein reports grants, personal fees, and nonfinancial support from Shire, CSL Behring, and Pharming Healthcare; grants and personal fees from Biocryst; and nonfinancial support from HAEA, unrelated to this study.

Bradykinin and interleukin-1ß synergistically increase the expression of cyclooxygenase-2 through the RNA-binding protein HuR in rat dorsal root ganglion cells.

Synergistic expression of cyclooxygenase-2 (COX-2) by interleukin-1ß (IL-1ß) and bradykinin (BK) in peri-sensory neurons results in the production of prostanoids, which affects sensory neuronal activity and responsiveness and causes hyperalgesia. To evaluate the effects of pro-inflammatory mediators on COX-2 expression, cultured rat dorsal root ganglion (DRG) cells were treated with IL-1ß and BK, which caused persistent increased COX-2 expression. Co-treatment increased COX-2 transcriptional activities in an additive manner by a COX-2 promoter luciferase assay. Immunoprecipitated HuR, an RNA-binding protein, in co-treated DRG cells contained more COX-2 mRNA than that of the control. The synergistic effects of IL-1ß and BK on COX-2 expression may be a result of RNA stabilization mediated by HuR in peri-sensory neurons. Multiple pro-inflammatory cytokines and mediators are produced during neurogenic inflammation and aberrant control of COX-2 mRNA turnover may be implicated in diseases including chronic inflammation, which results in inflammation-derived hyperalgesia around primary sensory neurons.

Bradykinin B1 receptor contributes to interleukin-8 production and glioblastoma migration through interaction of STAT3 and SP-1.

Glioblastoma (GBM), the most aggressive brain tumor, has a poor prognosis due to the ease of migration to surrounding healthy brain tissue. Recent studies have shown that bradykinin receptors are involved in the progression of various cancers. However, the molecular mechanism and pathological role of bradykinin receptors remains unclear. We observed the expressions of two major bradykinin receptors, B1R and B2R, in two different human GBM cell lines, U87 and GBM8901. Cytokine array analysis showed that bradykinin increases the production of interleukin (IL)-8 in GBM via B1R. Higher B1R levels correlate with IL-8 expression in U87 and GBM8901. We observed increased levels of phosphorylated STAT3 and SP-1 in the nucleus as well. Using chromatin immunoprecipitation assay, we found that STAT3 and SP-1 mediate IL-8 expression, which gets abrogated by the inhibition of FAK and STAT3. We further demonstrated that IL-8 expression and cell migration are also regulated by the SP-1. In addition, expression levels of STAT3 and SP-1 positively correlate with clinicopathological grades of gliomas. Interestingly, our results found that inhibition of HDAC increases IL-8 expression. Moreover, stimulation with bradykinin caused increases in acetylated SP-1 and p300 complex formation, which are abrogated by inhibition of FAK and STAT3. Meanwhile, knockdown of SP-1 and p300 decreased the augmentation of bradykinin-induced IL-8 expression. These results indicate that bradykinin-induced IL-8 expression is dependent on B1R which causes phosphorylated STAT3 and acetylated SP-1 to translocate to the nucleus, hence resulting in GBM migration.

Effect of the bradykinin 1 receptor antagonist SSR240612 after oral administration in Mycobacterium tuberculosis-infected mice.

The role, if any, played by the kinin system in tuberculosis infection models, either in vivo or in vitro, was investigated. The effects of Mycobacterium tuberculosis infection on C57BL/6 wild type, B1R-/-, B2R-/- and double B1R/B2R knockout mice were evaluated. Immunohistochemistry analysis was carried out to assess B1R and B2R expression in spleens and lungs of M. tuberculosis-infected mice. In addition, in vitro experiments with M. tuberculosis-infected macrophages were performed. The in vivo effects of HOE-140 and SSR240612 on the mice model of infection were also evaluated. Infected B2R-/- mice exhibited increased splenomegaly, whereas decreased spleen weight in infected double B1R/B2R knockout mice was observed. The bacterial load, determined as colony-forming units, did not differ in the spleens and lungs of the studied mouse strains. Importantly, immunohistochemical analysis revealed that B1R was upregulated in both spleens and lungs of infected mice. M. tuberculosis-infected macrophages incubated with SSR240612, alone or in combination with des-Arg9-BK, for four days, displayed a marked inhibitory effect on CFU counts. However, the pre-incubation of the selective B1R (des-Arg9-BK and SSR240612) and B2R (BK and HOE-140) agonists and antagonists, respectively, did not significantly affect the bacterial loads. A statistically significant reduction in the CFU of M. tuberculosis in lungs and spleens of animals treated with SSR240612, but not with HOE-140, was observed. Further efforts should be pursued to clarify whether or not SSR240612 might be considered an option for the treatment of tuberculosis.

Opposing effects of bronchopulmonary C-fiber subtypes on cough in guinea pigs.

We have addressed the hypothesis that the opposing effects of bronchopulmonary C-fiber activation on cough are attributable to the activation of C-fiber subtypes. Coughing was evoked in anesthetized guinea pigs by citric acid (0.001-2 M) applied topically in 100-µl aliquots to the tracheal mucosa. In control preparations, citric acid evoked 10 ± 1 coughs cumulatively. Selective activation of the pulmonary C fibers arising from the nodose ganglia with either aerosols or continuous intravenous infusion of adenosine or the 5-HT3 receptor-selective agonist 2-methyl-5-HT nearly abolished coughing evoked subsequently by topical citric acid challenge. Delivering adenosine or 2-methyl-5-HT directly to the tracheal mucosa (where few if any nodose C fibers terminate) was without effect on citric acid-evoked cough. These actions of pulmonary administration of adenosine and 2-methyl-5-HT were accompanied by an increase in respiratory rate, but it is unlikely that the change in respiratory pattern caused the decrease in coughing, as the rapidly adapting receptor stimulant histamine also produced a marked tachypnea but was without effect on cough. In awake guinea pigs, adenosine failed to evoke coughing but reduced coughing induced by the nonselective C-fiber stimulant capsaicin. We conclude that bronchopulmonary C-fiber subtypes in guinea pigs have opposing effects on cough, with airway C fibers arising from the jugular ganglia initiating and/or sensitizing the cough reflex and the intrapulmonary C fibers arising from the nodose ganglia actively inhibiting cough upon activation.

Expression, distribution and function of kinin B1 receptor in the rat diabetic retina.

BACKGROUND AND PURPOSE: The kinin B1 receptor contributes to vascular inflammation and blood-retinal barrier breakdown in diabetic retinopathy (DR). We investigated the changes in expression, cellular localization and vascular inflammatory effect of B1 receptors in retina of streptozotocin diabetic rats. EXPERIMENTAL APPROACH: The distribution of B1 receptors on retinal cell types was investigated by immunocytochemistry. Effects of B1 receptor agonist, R-838, and antagonist, R-954, on retinal leukocyte adhesion, gene expression of kinin and VEGF systems, B1 receptor immunoreactivity, microgliosis and capillary leakage were measured. Effect of B1 receptor siRNA on gene expression was also assessed. KEY RESULTS: mRNA levels of the kinin and VEGF systems were significantly enhanced at 2 weeks in streptozotocin (STZ)-retina compared to control-retina and were further increased at 6 weeks. B1 receptor mRNA levels remained increased at 6 months. B1 receptor immunolabelling was detected in vascular layers of the retina, on glial and ganglion cells. Intravitreal R-838 amplified B1 and B2 receptor gene expression, B1 receptor levels (immunodetection), leukostasis and vascular permeability at 2 weeks in STZ-retina. Topical application (eye drops) of R-954 reversed these increases in B1 receptors, leukostasis and vascular permeability. Intravitreal B1 receptor siRNA inhibited gene expression of kinin and VEGF systems in STZ-retina. Microgliosis was unaffected by R-838 or R-954 in STZ-retina. CONCLUSION AND IMPLICATIONS: Our results support the detrimental role of B1 receptors on endothelial and glial cells in acute and advanced phases of DR. Topical application of the B1 receptor antagonist R-954 seems a feasible therapeutic approach for the treatment of DR.

The relevance of kalikrein-kinin system via activation of B2 receptor in LPS-induced fever in rats.

PURPOSE: This study evaluated the involvement of endogenous kallikrein-kinin system and the bradykinin (BK) B1 and B2 receptors on LPS- induced fever and the POA cells involved in this response. MATERIAL AND METHODS: Male Wistar rats received either i.v. (1 mg/kg), i.c.v. (20 nmol) or i.h. (2 nmol) injections of icatibant (B2 receptor antagonist) 30 or 60 min, respectively, before the stimuli. DALBK (B1 receptor antagonist) was given either 15min before BK (i.c.v.) or 30 min before LPS (i.v.). Captopril (5 mg/kg, sc.,) was given 1 h prior LPS or BK. Concentrations of BK and total kininogenon CSF, plasma and tissue kallikrein were evaluated. Rectal temperatures (rT) were assessed by telethermometry. Ca++ signaling in POA cells was performed in rat pup brain tissue microcultures. RESULTS: Icatibant reduced LPS fever while, captopril exacerbated that response, an effect abolished by icatibant. Icatibant (i.h.) reduced fever to BK (i.h.) but not that induced by LPS (i.v.). BK increased intracellular calcium concentration in neurons and astrocytes. LPS increased levels of bradykinin, tissue kallikrein and total kininogen. BK (i.c.v.) increased rT and decreased tail skin temperature. Captopril potentiated BK-induced fever an effect abolished by icatibant. DALBK reduced the fever induced by BK. BK (i.c.v.) increased the CSF PGE2concentration. Effect abolished by indomethacin (i.p.). CONCLUSIONS: LPS activates endogenous kalikrein-kinin system leading to production of BK, which by acting on B2-receptors of POA cells causes prostaglandin synthesis that in turn produces fever. Thus, a kinin B2-receptor antagonist that enters into the brain could constitute a new and interesting strategy to treat fever.

Treatment of hereditary angioedema due to C1 inhibitor deficiency in Argentina

The benefits of the worldwide approval of new drugs for the treatment of acute C1-INH-HAE attacks may still not reach all patients. Identifying the current barriers in the access to medication, as well as conducting a detailed assessment of the progress in this area, is essential to achieve universal treatment. Two hundred and twenty five patients registered in the Argentina Hereditary Angioedema Patient Association (AHAEPA) were randomly selected and invited to participate in a web based questionnaire on accessibility to icatibant and pdC1-INH, self-treatment, delay to treatment, and coverage. The data retrieved was compared to our previous reports in 2008 and 2013. We collected 156/225 answers. One hundred and eighteen (76%) patients have either pdC1-INH (n = 86), icatibant (n = 10) or both (n = 22), while 38 (24%) do not have access to treatment. In 2008, 26% had access while 82% had it in 2013. Thirty-two subjects (22%) self-inject themselves, similar to 29% in 2013, even though between studies, widespread self-injection training activities have taken place. However, considering injections by proxy, home treatment reached 56%. Only half of the patients decide to receive treatment early during the attack. Ninety-nine patients (63%) have full coverage, thirty (19%) have no coverage at all and the rest only obtain partial reimbursement. Twenty-nine families (31%) share a single treatment dose of the medication, better than 36% in 2013. Argentina's C1-INH-HAE patients had a sustained improvement in their access to medication. Efforts should continue to further improve accessibility and optimal management of HAE acute attacks to all patients in the country.

La aprobación mundial de los medicamentos para el ataque agudo del angioedema hereditario (HAE) no beneficia a todos los pacientes. Es necesario conocer las barreras de acceso a la medicación para el tratamiento universal. Doscientos veinticinco pacientes, registrados en la Asociación de Pacientes con Angioedema Hereditario (AHAEPA), fueron encuestados por internet acerca de su accesibilidad al icatibant y al concentrado del inhibidor de C1 (pdC1-INH), a la auto inyección de la medicación, al retraso del tratamiento y a la cobertura del medicamento. Comparamos esta información con la obtenida en nuestros estudios de 2008 y 2013. Recolectamos 156/225 respuestas. Ciento dieciocho (76%) pacientes tienen pdC1-INH (n = 86), icatibant (n = 10) o ambos (n = 22), mientras que 38 (24%) no tienen medicación. En 2008, 26% tenían acceso y en 2013, 82%. Treinta y dos (22%) se autoinyectan la medicación, similar al 29% en 2013. Sumando las aplicaciones por profesionales de la salud o familiares en la casa, el tratamiento fuera de las instituciones médicas alcanza el 56%. Solo la mitad decide tratarse tempranamente. Noventa y nueve (63%) tiene cobertura del 100%, 30 (19%) no tiene ningún tipo de cobertura, y el resto la tiene en forma parcial. Veintinueve familias (31%), solo tienen una dosis de tratamiento para todos, mejor que el 36% en 2013. Los pacientes con C1-INH-HAE han tenido una mejoría sustancial en el acceso a la medicación. Igualmente, los esfuerzos deben continuar para mejorar la accesibilidad y tratamiento óptimo de todos.

Central Administration of Galanin Receptor 1 Agonist Boosted Insulin Sensitivity in Adipose Cells of Diabetic Rats.

Our previous studies testified the beneficial effect of central galanin on insulin sensitivity of type 2 diabetic rats. The aim of the study was further to investigate whether central M617, a galanin receptor 1 agonist, can benefit insulin sensitivity. The effects of intracerebroventricular administration of M617 on insulin sensitivity and insulin signaling were evaluated in adipose tissues of type 2 diabetic rats. The results showed that central injection of M617 significantly increased plasma adiponectin contents, glucose infusion rates in hyperinsulinemic-euglycemic clamp tests, GLUT4 mRNA expression levels, GLUT4 contents in plasma membranes, and total cell membranes of the adipose cells but reduced the plasma C-reactive protein concentration in nondiabetic and diabetic rats. The ratios of GLUT4 contents were higher in plasma membranes to total cell membranes in both nondiabetic and diabetic M617 groups than each control. In addition, the central administration of M617 enhanced the ratios of pAkt/Akt and pAS160/AS160, but not phosphorylative cAMP response element-binding protein (pCREB)/CREB in the adipose cells of nondiabetic and diabetic rats. These results suggest that excitation of central galanin receptor 1 facilitates insulin sensitivity via activation of the Akt/AS160 signaling pathway in the fat cells of type 2 diabetic rats.

Contribution of the Kallikrein/Kinin System to the Mediation of ConA-Induced Inflammatory Ascites.

Intraperitoneal administration of concanavalin A (ConA, 25 mg/kg b.w.), a cell-binding plant lectin was used for inducing inflammatory ascites, and potential inhibitors were tested in 1 h and 2.5 h experiments, i.e. still before the major influx of leucocytes. At the end of the experiment the peritoneal fluid was collected and measured. The ConA-induced ascites was significantly (p<0.01) and dose-dependently inhibited by icatibant (HOE-140), a synthetic polypeptide antagonist of bradykinin receptors. Aprotinin, a kallikrein inhibitor protein also had significant (p<0.01), but less marked inhibitory effect. L-NAME, an inhibitor of NO synthesis, and atropine methylnitrate, an anticholinergic compound, were ineffective. It is concluded, that the kallikrein/kinin system contributes to the mediation of the ConA-induced ascites by increasing subperitoneal vascular permeability, independent of the eventual vasodilation produced by NO. It is known, that membrane glycoproteins are aggregated by the tetravalent ConA and the resulting distortion of membrane structure may explain the activation of the labile prekallikrein. Complete inhibition of the ConA-induced ascites could not be achieved by aprotinin or icatibant, which indicates the involvement of additional mediators.

Prophylaxis in hereditary angioedema (HAE) with C1 inhibitor deficiency.

Hereditary angioedema (HAE) is a rare congenital disorder characterized by recurrent episodes of subcutaneous or submucosal edema. Laryngeal manifestations can be life-threatening. In the majority of cases, the disease can be adequately treated with an on-demand approach--in some cases, however, short- or long-term prophylaxis is indicated. Attenuated androgens used to be the drugs of choice, but they are associated with considerable side effects and no longer commercially available in the German-speaking countries of the EU. They are currently being replaced by more effective and more tolerable agents such C1-inhibitors, the kallikrein inhibitor ecallantide, and the B2 receptor antagonist icatibant, which have recently obtained market authorization. These new drugs have had a major impact, especially on the indications and procedures for long-term prophylaxis. According to the most recent international consensus papers and our own experience, self-administered C1-inhibitors are now the first option for long-term prophylactic therapy. The decision for prophylaxis should no longer be based on single parameters such as the frequency of attacks but on adequate overall disease control including quality of life. More drugs are currently being developed, which may lead to further changes in the treatment algorithms of HAE.

Novel usage of fresh frozen plasma in hereditary angioedema.

Hereditary angioedema (HAE) is a rare and potentially life threatening autosomal dominant disease characterized by recurrent episodes of cutaneous and mucosal oedema. It results from reduced expression or loss of function of CI-esterase inhibitors (C1-INH). As opposed to the more common histamine-mediated angioedema, HAE does not respond well to conventional treatments with anti-histamines, steroids and adrenaline. Early recognition and timely intervention with the correct treatment are crucial particularly preventing airway obstruction. New disease specific treatment including plasma derived or recombinant C1-INH, ecallantide and icatibant have recently emerged and its appropriate use can reduce HAE-associated mortality and morbidity. However due to its costs, these disease specific treatments have yet to reach Malaysia. Despite that no randomized clinical trial on FFP has been performed, its efficacy in treating acute attacks of HAE is only demonstrated in case studies. This case report illustrates the successful treatment of acute HAE episode with FFP in a Malaysian government hospital setting.

Differential effect of intranasally administrated kinin B1 and B2 receptor antagonists in Alzheimer's disease mice.

An Increasing body of evidence supports a critical role of brain inflammation in the pathogenesis of Alzheimer's disease. A principal aspect of the brain immune response to inflammation is the activation of microglia. It has been shown that the kinin system is activated during brain inflammation and previously we demonstrated that bradykinin B1 receptor agonist reduced microglial activation in vitro. The aim of the present study was to investigate the effects of bradykinin B1 or B2 receptor antagonists on microglial release of pro-inflammatory factors in BV2 microglia. In vivo, we focused on the effects of intranasally given kinin antagonists on amyloid burden and microglia/macrophage marker expression in brains of 5X familial Alzheimer's disease mice. The present data show that pharmacological antagonism of B1 receptor (R-715) but not B2 receptor (HOE-140) markedly increased nitric oxide and tumor necrosis factor alpha release from BV2 microglial cells. We also showed that intranasal treatment with R-715 but not HOE-140 of Alzheimer's mice enhanced amyloid beta burden and microglia/macrophages activation. Taken together, our data reveal a possible role for the bradykinin B1 receptor in neuroinflammation and in the control of Abeta accumulation in transgenic mice, possibly through regulation of glial cell responses.

Bradykinin Impairs and HOE 140 does not Protect Rat Hindlimb Skeletal Muscle Against Tourniquet-induced Reperfusion Injury.

BACKGROUND: Bradykinin (BK) is used in different tissues. Dose-dependent studies have demonstrated that low doses protect against ischemia/reperfusion (I/R) injury while higher doses lead to adverse effects. Although the beneficial effects of BK infusion were observed in myocardium, its role on the I/R impact in skeletal muscle (SM) has not been fully clarified. OBJECTIVE: This study was carried out to evaluate the effects of BK, administered in the hindlimbs of rats subjected to I/R. METHODS: The study design included three experimental groups: Group 1 control (saline), Group 2 (bradykinin), and Group 3 (HOE 140, a BK2 receptor blocker). In all three groups, rats were subjected to hindlimb ischemia for a total of 2 h followed by continuous 4 h of reperfusion with pharmacological interventions. The methods include analysis of enzymes (lactate dehydrogenase-LDH and creatinine phosphokinase-CPK), cell membrane marker of injury (malondialdeyde-MDA), recruitment of neutrophils (myeloperoxidase-MPO), and apoptosis index (immunohistochemistry TUNEL in situ peroxidase dead end). RESULTS: Except for the apoptotic index, all parameters studied were shown to be elevated in the reperfusion group intervened with BK. The blocking of BK2 receptors by HOE 140 did not affect the I/R injury. CONCLUSION: After 2 h of total ischemia, infusion of bradykinin during 4 h of reperfusion, worsened the I/R injury in the hindlimb skeletal muscle.

Kinin B1 Receptor Antagonist BI113823 Reduces Acute Lung Injury.

OBJECTIVES: This study was undertaken to examine the effects of BI113823, a potent small molecule orally active nonpeptide B1 receptor antagonist, in an experimental model of endotoxin-induced direct lung injury in mice and indirect lung injury and survival in cecal ligation and puncture-induced polymicrobial sepsis in rats. DESIGN: Experimental, prospective study. SETTING: University research laboratory. SUBJECTS: Male BALB/c mice and male Wistar rats. INTERVENTIONS: Series 1: acute lung injury was induced in mice by intratracheal injection of lipopolysaccharide. Mice were then randomly assigned to receive treatment of vehicle, BI113823, or dexamethasone. Bronchoalveolar lavage fluid and lung tissues were analyzed for inflammatory cell influx and various histologic variables. Series 2: sepsis was induced by cecal ligation and puncture in anesthetized rats. Animals were then randomly assigned to receive treatment of vehicle or BI113823. Experiments were terminated at 20 hours and 7 days following cecal ligation and puncture, respectively. MEASUREMENTS AND MAIN RESULTS: Series 1: treatment with BI113823 significantly reduced lipopolysaccharide-induced neutrophil influx in bronchoalveolar lavage fluid. The BI113823 group had significantly lower lung vascular permeability, lung water content, myeloperoxidase activity, lung apoptosis and lung injury scores, total protein content, and tumor necrosis factor-α and interleukin-1ß levels compared with vehicle controls. In addition, nuclear factor-κB phosphorylation, nuclear translocation, and cyclooxygenase-2 and inducible nitric oxide synthase expression in the lung were attenuated in BI113823-treated animals compared with vehicle controls. Series 2: BI113823 significantly reduced sepsis-induced macrophage recruitment, protein content, and tumor necrosis factor-α and interleukin-1ß levels in lavage fluid and also reduced lung water content and plasma levels of tumor necrosis factor-α and interleukin-6 compared with vehicle controls. Most importantly, treatment with BI113823 significantly improved survival following severe sepsis in rats. CONCLUSIONS: Administration of B1 receptor antagonist BI113823 significantly reduced endotoxin-induced direct lung injury and also reduced sepsis-induced lung inflammatory response. Most importantly, BI113823 improved survival following severe polymicrobial sepsis.

Afferent fibers involved in the bradykinin-induced cardiovascular reflexes from the ovary in rats.

Bleeding or rupture of the ovary often accompanies ovarian cysts and causes severe pain and autonomic responses such as hypotension. It would be expected that ovarian afferents contribute to cardiovascular responses induced by ovarian failure. The present study examined cardiovascular responses to noxious chemical stimulation of the ovary by bradykinin, an algesic substance released by tissue damage, and explored the role of ovarian afferents in the ovarian-cardiovascular responses in anesthetized rats. Non-pregnant adult rats were anesthetized with pentobarbital and artificially ventilated. The carotid artery was cannulated to monitor blood pressure and heart rate. Noxious chemical stimulation was achieved by applying a small piece of cotton soaked with bradykinin to the surface of the ovary for 30s. Application of bradykinin (10(-4) M) to the ovary decreased heart rate and blood pressure. These cardiovascular responses were not significantly influenced by severance of the vagal nerves or the superior ovarian nerve, but were abolished by severance of the ovarian nerve plexus (ONP). Application of bradykinin (10(-4) M) to the ovary evoked afferent activity of the ONP both in vivo and in vitro preparations. These results indicate that the decreases in heart rate and blood pressure following chemical noxious stimulation of the ovary with bradykinin are reflex responses, whose afferent nerve pathway is mainly through afferent fibers in the ONP.

[Prophylactic use of icatibant before tracheal intubation of a patient with hereditary angioedema type III. (A literature review of perioperative management of patients with hereditary angioedema type III)]. / Uso profiláctico de icatibant en un caso de angioedema hereditario tipo III. (Revisión de la literatura sobre manejo perioperatorio en pacientes con angioedema hereditario tipo III).

Type III hereditary angioedema is a rare familial disorder that has recently been described as a separate condition. Triggers for episodes of angioedema include surgery, dental procedures, and tracheal intubation maneuvers. Since episodes affecting the upper airway are potentially life-threatening, prophylactic treatment is recommended in these situations. The use of icatibant (Firazyr(®)), for prevention of angioedema prior to tracheal intubation, is reported in a patient with type iii hereditary angioedema. A literature review on the anesthetic management of this condition was conducted.

Bradykinin regulates osteoblast differentiation by Akt/ERK/NFκB signaling axis.

Bradykinin (BK), a well known mediator of pain and inflammation, is also known to be involved in the process of bone resorption. The present study therefore evaluated the role of BK in osteoblast lineage commitment. Our data showed that BK inhibits the migration of bone marrow mesenchymal stem cells, but does not affect their viability. Moreover, BK also inhibits osteoblastic differentiation by significantly downregulating the levels of mRNAs for osteopontin, runX2, col24, osterix, osteocalcin genes and bone mineralization (P < 0.05). Further, BK was found to elicit the BK receptors (BDKR1 and BDKR2) mediated activation of ERK1/2 and Akt pathways, which finally led to the activation of NFκB. BK also promoted the osteoclast differentiation of bone marrow derived preosteoclast cells by upregulating the expression of c-fos, NFATC1, TRAP, clcn7, cathK, and OSCAR genes and increasing TRAP activity through NFκB pathway. In conclusion, our data suggest that BK decreases the differentiation of osteoblasts with concomitant increase in osteoclast formation and thus provides new insight into the mechanism of action of BK in modulating bone resorption.

Trabecular meshwork bradykinin receptors: mRNA levels, immunohistochemical visualization, signaling processes pharmacology, and linkage to IOP reduction.

PURPOSE: To localize mRNA and protein of bradykinin (BK) receptors, BK precursor polypeptide (kininogen) mRNA, and to study functional biochemical pharmacology of the signal transduction processes mediated by B2-receptors in isolated human trabecular meshwork (h-TM) cells. Intraocular pressure (IOP) lowering effects of 2 kinins were also investigated. METHODS: Previously documented procedures were utilized throughout these studies. RESULTS: Kinninogen mRNA was most abundant in TM, ciliary body (CB), and optic nerve head and appeared elevated in glaucomatous h-TM tissue. High levels of B2-receptor mRNA were found in the sclera, iris, TM, and CB. B2-receptor subtype protein was localized in cells of the monkey and h-TM, and the treatment of isolated h-TM cells with transforming growth factor-ß2 (5 ng/mL) caused significant (P<0.04) downregulation of B2-receptor mRNA. In isolated primary h-TM cells, BK (EC50=0.8±0.2 nM; n=19) and Met-Lys-BK (EC50=6.5±1.5 nM) mobilized intracellular Ca(2+) and induced the release of prostaglandins (PGs) that was blocked by 2 B2-receptor antagonists [HOE-140; (S)-WIN-64338]. The cyclooxygenase inhibitor, bromfenac, abolished BK-induced PGs production. BK concentration dependently increased cell impedance, and it significantly (P<0.05) decreased h-TM cell volume in vitro. Intravitreal (ivt) administration of BK (50 µg), but not a B1-agonist (Sar-[D-Phe(9)]-Des-Arg(9)-BK; also at 50 µg), efficaciously lowered IOP (22.9% to 37% from baseline) of Dutch-Belted rabbits that naturally have high IOPs (27-28 mmHg). CONCLUSIONS: BK activates multiple signal transduction pathways in h-TM cells via B2-receptors that also mediate IOP reduction as observed in rabbits following ivt administration of BK. These ocular hypotensive effects of BK may be physiologically important and suggest a novel therapeutic potential of BK-related B2-agonists.