The role of B1 and B2 kinin receptors in oedema formation after long-term treatment with Mycobacterium bovis bacillus Calmette-Guérin (BCG)

Kinins and Their Receptors in Infectious Diseases

Kinins and their receptors have been implicated in a series of pathological alterations, representing attractive pharmacological targets for several diseases. The present review article aims to discuss the role of the kinin system in infectious diseases. Literature data provides compelling evidence about the participation of kinins in infections caused by diverse agents, including viral, bacterial, fungal, protozoan, and helminth-related ills. It is tempting to propose that modulation of kinin actions and production might be an adjuvant strategy for management of infection-related complications.

Evaluation of anti-inflammatory activity and molecular docking study of new aza-bicyclic isoxazoline acylhydrazone derivatives

The aim of this study was to investigate the anti-inflammatory effects of two new isoxazoline-acylhydrazone derivatives: N'-(4-methoxybenzylidene)-6-(4-nitro-benzoyl)-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,2-d]isoxazole-3-carbohydrazide (R-123) and N'-(4-chlorobenzylidene)-6-(4-chlorobenzoyl)-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,2-d]isoxazole-3-carbohydrazide (R-99). An air pouch induced by carrageenan was used for screening the best dose of R-99 and R-123. Using this mouse model, leukocyte migration and cytokine levels (TNF-α and IL-1β) were determined. Paw edema induced by several phlogistic agents and vascular permeability induced by acetic acid were employed to investigate the mechanism of action of the isoxazoline-acylhydrazone derivatives. A docking study was performed with the human histamine H1 receptor to investigate potential antihistaminic activity. Treatment with the compounds reduced leukocyte migration in the air pouch at all doses tested. TNF-α and IL-1β levels were similarly reduced by the two compounds. Vasoactive amines were inhibited in models of paw edema induced by several agents and vascular permeability induced by acetic acid. The docking study suggests that R-99 and R-123 may be inhibitors of the histamine H1 receptor. In conclusion, the results indicate that R-99 and R-123 exhibit promising anti-inflammatory activity related to their ability to inhibit TNF-α, IL-1β, and vasoactive amine production, as well as reduce leukocyte migration and inhibit mast cell degranulation.

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.

Pharmacological Activities and Hydrolysis by Peptidases of [Phospho-Ser(6)]-Bradykinin (pS(6)-BK)

Phosphorylated kininogen and some of its fragments containing serine phosphorylated bradykinin ([pS(6)]-Bk) were identified in human serum and plasma by a phosphoproteomic approach. We report the kininogenase ability of human tissue and plasma kallikreins and tryptase to generate [pS(6)]-Bk or Lys-[pS(6)]-Bk having as substrate the synthetic human kininogen fluorescent fragment Abz-MISLMKRPPGF[pS(386)]PFRSSRI-NH2. The pharmacological assays of [pS(6)]-Bk showed it as a full B2 bradykinin receptor agonist in smooth muscle, it produces a portal liver hypertensive response in rat and mouse paw edema that lasts longer than Bk. The rat hypotensive response to infusions of Bk is greater than that of [pS(6)]Bk, both if injected through femoral vein or aorta. [pS(6)]-Bk was more resistant than Bk to kininase digestion performed with angiotensin converting enzyme, neprilysin, thimet oligopeptidase, aminopeptidase P and carboxypeptidase M. (1)H-NMR experiments indicated that [pS(6)]-Bk has lower flexibility, with the pS(6)-P(7) bond restricted to the trans conformation, and can explain [pS(6)]-Bk resistance to hydrolysis. In conclusion, [pS(6)]-Bk presenting lower activity than Bk, with longer lasting effects and being slowly released by kininogenases from synthetic Abz-MISLMKRPPGF[pS(386)]PFRSSRI-NH2, suggests that phosphorylation of the kininogens can be an efficient kallikrein-kinin system regulator.

Renin-angiotensin system inhibitors and angioedema: anesthetic implications

PURPOSE OF REVIEW

Angioedema is a serious complication of renin-angiotensin system inhibitor therapy. The incidence is 0.1-0.7%. It consists of nonpitting edema and involves the face and lips. In severe cases, it extends to pharyngeal and laryngeal structures.

RECENT FINDINGS

Decreased degradation of bradykinin and its metabolites is thought to be a culprit. When the angiotensin-converting enzyme is inhibited, bradykinin metabolism is dependent on degradation by neutral endopeptidase, dipeptidyl peptidase IV, and aminopeptidase P. When these enzymes are inhibited, as in treatment of diabetes or in transplant recipients, the incidence of angioedema increases significantly. African-Americans, people over 65, women, and those with a history of smoking are especially at risk. A fiberoptic laryngeal examination should be performed in all patients. Patients with rapid progression of symptoms are at risk for airway compromise. Supportive treatment with steroids and antihistamines is not very effective. Recently, icatibant, a bradykinin receptor antagonist, has been used to successfully shorten the resolution of edema.

SUMMARY

Trauma of the airway, especially during difficult intubation, may precipitate severe angioedema. In cases with laryngeal involvement, fiberoptic intubation may be necessary. After the episode of angioedema, lifetime discontinuation of all renin-angiotensin inhibitors may be warranted.

Non-peptide antagonists for kinin B1 receptors: new insights into their therapeutic potential for the management of inflammation and pain

Kinin B1 and B2 receptors are central to the aetiology of pain and inflammation. Constitutive B2 receptors are commonly associated with the acute phase of inflammation and nociception, whereas the inducible B1 receptors are mostly linked to the chronic or persistent phase (or both). Therefore, selective, orally active kinin B1 receptor antagonists could be potentially therapeutic. B1 receptor antagonists have long been exclusively peptides, but recently a few non-peptide representatives have been identified. The clinical potential of these non-peptide molecules has not yet been evaluated, but they might have a role in treating persistent inflammation and pain, especially when no satisfactory therapy is available. This review summarizes recent advances in the identification and the potential therapeutic properties of these molecules.

Mechanisms underlying the modulatory action of platelet activating factor (PAF) on the upregulation of kinin B1 receptors in the rat paw

1. The present study evaluated the ability of the administration of platelet activating factor (PAF) to induce the upregulation of B(1) receptors in the rat paw. 2. Local treatment with PAF resulted in a time-dependent increase of oedema formation induced by the B(1) receptor agonist des-Arg(9)-BK (des-Arg(9)-bradykinin), but not by the B(2) receptor agonist tyrosine(8)-bradykinin. Functional upregulation of B(1) receptors was accompanied by a prominent increase of B(1) receptor mRNA expression in the rat paw. 3. In PAF-treated paws, des-Arg(9)-BK-induced oedema formation was significantly inhibited by the B(1) receptor antagonists des-Arg(9)-[Leu(8)]-BK and R-715. The effects of PAF pretreatment were receptor operated, as assessed by the effects of the PAF receptor antagonist WEB2086 or by desensitisation of PAF receptors. 4. The protein synthesis inhibitor cycloheximide, the anti-inflammatory steroid dexamethasone or the nuclear factor (NF-kappaB) blockers pyrrolidine-dithiocarbamate (PDTC) and Nalpha-tosyl-L-chloromethylketone significantly blocked the functional upregulation of B(1) receptors. 5. The selectin inhibitor fucoidin, an anti-CD18 antibody or an anti-rat neutrophil antiserum, also significantly prevented des-Arg(9)-BK-induced paw oedema in rats pretreated with PAF. 6. Intradermal injection of PAF induced a 25-fold increase of myeloperoxidase activity in the rat paw, a response that was significantly inhibited by fucoidin, anti-CD-18, anti-rat neutrophil antiserum or PDTC. 7. Local treatment with PAF also resulted in a marked increase of NF-kappaB activation, an effect largely prevented by PDTC or by the anti-rat neutrophil antiserum. 8. Collectively, the present results indicate that the induction of B(1) receptors following treatment with the chemotatic mediator PAF is dependent on the recruitment of neutrophils, an event that is under the control of adhesion molecules, protein synthesis and NF-kappaB activation. These findings provide new insights into the role played by cell migration and chemotatic factors on B(1) receptor upregulation in vivo.

The expression of bradykinin B(1) receptors on primary sensory neurones that give rise to small caliber sciatic nerve fibres in rats

The bradykinin B(1) receptor has been considered as an important mediator for inflammatory pain. In the present study, we have investigated the fibre types of sciatic nerve primary sensory neurones that express B(1) receptors by retrograde tracing in combination with immunohistochemical staining, or double-immunohistochemical staining. Approximately 12% of the A-fibre dorsal root ganglion neurones, retrogradely labelled from an intra-sciatic nerve injection of fluorescein isothiocyanate-conjugated cholera toxin B subunit, were B(1) receptor-immunoreactive. Over 70% of the small diameter dorsal root ganglion neurones, retrogradely labelled from an intra-sciatic nerve injection of tetramethylrhodamine isothiocyanate-conjugated wheat germ agglutinin, were B(1) receptor-immunoreactive. Over 50% of the (predominantly non-peptidergic) C-fibre dorsal root ganglion neurones, retrogradely labelled from an intra-sciatic nerve injection of fluorescein isothiocyanate-conjugated Bandeiraea simplicifolia isolectin B4, were B(1) receptor-immunoreactive. When calcitonin gene-related peptide, which is contained mainly in small caliber C- and A(delta)-fibre primary afferents, and B(1) receptors were stained with a double-immunofluorescent method, over 80% of the calcitonin gene-related peptide-positive dorsal root ganglion neurones were B(1) receptor-immunoreactive. From these results we suggest that B(1) receptors are predominantly expressed by small diameter primary afferent neurones that give rise to sciatic nerve fibres, which include both peptidergic and non-peptidergic C-fibres and A(delta)-fibres. Since peripheral nociceptive information is primarily transmitted by C- and A(delta)-fibres, B(1) receptors may be involved in the modulation of nociceptive transduction or transmission.

Kinin receptors in pain and inflammation

Kinins are among the most potent autacoids involved in inflammatory, vascular and pain processes. These short-lived peptides, including bradykinin, kallidin and T-kinin, are generated during tissue injury and noxious stimulation. However, emerging evidence also suggests that kinins are stored in neuronal elements of the central nervous system (CNS) where they are thought to play a role as neuromediators in various cerebral functions, particularly in the control of nociceptive information. Kinins exert their biological effects through the activation of two transmembrane G-protein-coupled receptors, denoted bradykinin B(1) and B(2). Whereas the B(2) receptor is constitutive and activated by the parent molecules, the B(1) receptor is generally underexpressed in normal tissues and is activated by kinins deprived of the C-terminal Arg (des-Arg(9)-kinins). The induction and increased expression of B(1) receptor occur following tissue injury or after treatment with bacterial endotoxins or cytokines such as interleukin-1 beta and tumor necrosis factor-alpha. This review summarizes the most recent data from various animal models which convey support for a role of B(2) receptors in the acute phase of the inflammatory and pain response, and for a role of B(1) receptors in the chronic phase of the response. The B(1) receptor may exert a strategic role in inflammatory diseases with an immune component (diabetes, asthma, rheumatoid arthritis and multiple sclerosis). New information is provided regarding the role of sensory mechanisms subserving spinal hyperalgesia and intrapleural neutrophil migration that occur upon B(1) receptor activation in streptozotocin-treated rats, a model of insulin-dependent diabetes mellitus in which the B(1) receptor seems to be rapidly overexpressed. Although it is widely accepted that the blockade of kinin receptors with specific antagonists could be of benefit in the treatment of somatic and visceral inflammation and pain, recent molecular and functional evidence suggests that the activation of B(1) receptors with an agonist may afford a novel therapeutic approach in the CNS inflammatory demyelinating disorder encountered in multiple sclerosis by reducing immune cell infiltration (T-lymphocytes) into the brain. Hence, the B(1) receptor may exert either a protective or detrimental effect depending on the inflammatory disease. This dual function of the B(1) receptor deserves to be investigated further.

Changes in paw oedema triggered via bradykinin B(1) and B(2) receptors in streptozotocin-diabetic rats

The present study investigated hind paw oedema mediated by bradykinin B(1) and B(2) receptors in streptozotocin-diabetic rats. Paw oedema induced by intraplantar (i.pl.) injection of bradykinin or the selective bradykinin B(2) receptor agonist, Tyrosine(8)-bradykinin ([Tyr(8)]bradykinin) (both 3 nmol/paw), was significantly reduced at 4 weeks after streptozotocin treatment (34 +/- 8% and 40 +/- 7%). At 6 weeks after streptozotocin, when paw oedema caused by substance P or prostaglandin E(2) (both 10 nmol/paw) was unchanged, inhibition of bradykinin B(2) receptor-mediated oedema was maximal (66 +/- 6% and 72 +/ -2%, for bradykinin and [Tyr(8)]bradykinin, respectively). The selective bradykinin B(1) receptor agonist, [des-Arg(9)]bradykinin (100 nmol/paw), induced only slight paw oedema in non-diabetic controls. Responses to [des-Arg(9)]bradykinin were markedly enhanced 8 weeks after streptozotocin (from 0.09 +/- 0.01 to 0.38 +/- 0.05 ml), less so at 10 weeks (0.22 +/- 0.03 ml), and returning to basal values at 12 weeks (0.11 +/- 0.03 ml). Treatment with insulin protamine zinc (1-3 U/day/7 weeks, s.c.) did not reverse the inhibition of responses to [Tyr(8)]bradykinin or the potentiation of responses to [des-Arg(9)]bradykinin seen at 8 weeks. Thus, streptozotocin-induced diabetes induces long-lasting alterations in oedematogenic responsiveness to kinins in the rat, characterized by marked reduction of oedema involving activation of bradykinin B(2) receptors, associated with enhancement of bradykinin B(1) receptor-mediated oedema.

The "in vivo" and "ex vivo" roles of cylcooxygenase-2, nuclear factor-kappaB and protein kinases pathways in the up-regulation of B1 receptor-mediated contraction of the rabbit aorta

This study investigates some of the mechanisms involved in the up-regulation of the B1 receptor in the rabbit aorta. Pre-treatment of rabbit aorta with cyclooxygenase (COX) inhibitors 5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsuphonyl) phenyl-2 (5H)-furanone (DFU), N-[2-cyclohexyloxy-4-nitrophenyl] methanesulfonamide (NS-398) or with indomethacin, but not with piroxicam, for 6 h, resulted in a significant inhibition of time-dependent contraction to the B1 selective agonist des-Arg9-Bradykinin (des-Arg9-BK), without affecting noradrenaline (NA) response. The kinase inhibitors bisindoylmaleimidine IX (RO 318220), staurosporine, genistein or tyrphostin B42 and the nuclear factor-kappaB (NF-kappaB) inhibitors pyrrolidinedithiocarbamate (PDTC), N(alpha)-p-tosyl-L-lysine chloro-methyl ketone (TLCK) or sulfasalazine, incubated for 6 h each, resulted in similar inhibition of des-Arg9-BK-induced contraction. When these inhibitors were pre-incubated for only 30 min, 6 h after setting up the preparations, sulfasalazine was the only drug tested that inhibited des-Arg9-BK-induced contraction, an effect which was reverted after the washing-out of the preparations. In preparations obtained from animals treated with lipopolysaccharide i.v. (LPS) 12 h prior, the up-regulation of B1 receptor in the aorta was markedly increased. The treatment of rabbits with PDTC, dexamethasone (Dexa), genistein or an association of subliminal doses of Dexa or with PDTC 12 h prior, which alone had no effect, all caused significant inhibition of des-Arg9-BK-induced contraction in the rabbit aorta. These results indicate that the time-dependent up-regulation of des-Arg9-BK-mediated contraction in the rabbit aorta involves the activation of protein kinase C, tyrosine kinase, through participation of COX-2 and the NF-kappaB transcription factor pathways.

Endotoxin sensitization to kinin B(1) receptor agonist in a non-human primate model: haemodynamic and pro-inflammatory effects

1. Although endotoxaemia induces kinin B(1) receptors in several animal models, this condition is not documented in primates. This study examined the up-regulation of haemodynamic and pro-inflammatory responses to the B(1) agonist des-Arg(10)-kallidin (dKD) in a non-human primate model. 2. Green monkeys (Cercopithecus aethiops St Kitts) received lipopolysaccharide (LPS; 90 microg kg(-1)) or saline intravenously. After 4 h, anaesthetized monkeys were cannulated via the carotid artery to monitor blood pressure changes following intra-arterial injections of dKD or the B(2) agonist bradykinin (BK). Oedema induced by subcutaneous kinin administration was evaluated as the increase in ventral skin folds in anaesthetized monkeys injected with captopril at 4 h to 56 days post-LPS. 3. LPS increased rectal temperature but did not affect blood pressure after 4 h. dKD reduced blood pressure (E(max): 27+/-4 mmHg; EC(50): 130 pmol kg(-1)) and increased heart rate (E(max): 33 b.p.m.) only after LPS. In contrast, the dose-dependent fall in blood pressure with BK was comparable in all groups. The selective B(1) antagonist [Leu(9)]dKD (75 ng kg(-1) min(-1), intravenously) abolished responses to dKD but not BK. 4. dKD injection induced oedema dose-dependently (2.4+/-0.1 mm at 150 nmol) only following LPS (at 4 h to 12 days but not 56 days). In contrast, BK-induced oedema was present and stable in all monkeys. Co-administration of [Leu(9)]dKD (150 nmol) significantly reduced oedema induced by dKD (50 nmol). 5. These results suggest LPS up-regulation of B(1) receptor effects in green monkeys. This non-human primate model may be suitable for testing new, selective B(1) antagonists with therapeutic potential as anti-inflammatory agents.

Molecular and pharmacological evidence for modulation of kinin B(1) receptor expression by endogenous glucocorticoids hormones in rats

1. The effect of endogenous glucocorticoid hormones on the expression of rat B(1) receptors was examined by means of molecular and pharmacological functional approaches. 2. Rats were adrenalectomized (ADX), and 7 days after this procedure the intradermal injection of B(1) receptor agonist des-Arg(9)-BK produced a significant increase in the paw volume, while only a weak effect was observed in sham-operated animals. A similar increase in the contractile responses mediated by B(1) agonist des-Arg(9)-BK was also observed in the rat portal vein in vitro. 3. Chemical ADX performed with mitotane (a drug that reduces corticosteroid synthesis) produced essentially the same up-regulation of B(1) receptors as that observed in ADX rats. 4. The modulation of B(1) receptor expression was evaluated by ribonuclease protection assay, employing mRNA obtained from the lungs and paw of ADX rats. 5. Additionally, both paw oedema and contraction of portal vein mediated by B(1) agonist des-Arg(9)-BK in ADX rats, were markedly inhibited by treatment with dexamethasone, or COX-2 inhibitor meloxican, or with the NF-kappaB inhibitor PDTC. Interestingly, the same degree of inhibition was achieved when the animals were treated with a combination of submaximal doses of dexamethasone and PDTC. 6. The involvement of NF-kappaB pathway was further confirmed by mobility shift assay using nuclear extracts from lung, paw and heart of ADX rats. It was also confirmed that the treatment of ADX rats with dexamethasone, PDTC or dexamethasone plus PDTC completely inhibit NF-kappaB activation caused by absence of endogenous glucucorticoid. 7. Together, the results of the present study provide, for the first time, molecular and pharmacological evidence showing that B(1) kinin receptor expression can be regulated through endogenous glucocorticoids by a mechanism dependent on NF-kappaB pathway. Clinical significance of the present findings stem from evidence showing the importance of B(1) kinin receptors in the mediation of inflammatory and pain related responses.

The role of sensorial neuropeptides in the edematogenic responses mediated by B(1) agonist des-Arg(9)-BK in rats pre-treated with LPS

In the present study we have investigated some of the mechanisms underlying B(1) kinin receptor-induced paw edema formation in rats that had been treated with LPS, paying special attention to the involvement of neurogenic inflammation. Intradermal (i.d.) injection of the B(1) receptor agonist des-Arg(9)-BK (100 nmol/paw) resulted in a marked increase in paw volume in animals pre-treated with LPS (0.40+/-0.06 ml). The co-injection of the selective NK(1) FK888 (1 nmol/paw) or NK(2) SR 48968 (3 nmol/paw) receptor antagonists resulted in a significant inhibition of the edema induced by des-Arg(9)-BK (30+/-4 and 25+/-7%, respectively). The NK(3) SR 142801 (3 nmol/paw) antagonist did not demonstrate any significant effect on B(1) receptor-mediated paw edema. The edema induced by des-Arg(9)-BK was also significantly inhibited (33+/-5%) by the co-injection of the CGRP-receptor antagonist CGRP 8-37 (1 nmol/paw) or by treatment of animals with capsaicin (50 mgkg(-1), s.c., 48 h, prior) (45+/-4%). The pre-treatment of animals with methysergide or with mianserin, 5-HT(1) and 5HT(2) antagonists, respectively (both 10 mgkg(-1), i.p. 30 min), resulted in a significant reduction of the edema mediated by B(1) receptors (23+/-5 and 20+/-3%, respectively). In addition, compound 48/80 (12 microg/paw, 24 h) significantly reduced des-Arg(9)-induced paw edema in rats pre-treated with LPS (23+/-3%), while the treatment of animals with the H(1) receptor antagonist pyrilamine (10 mgkg(-1), i.p., 30 min) failed to affect the edematogenic responses involving B(1) receptors. Finally, the co-injection of NOS inhibitors L-NAME (100 nmol/paw) or 7-NINA (10 nmol/paw) did not affect the rat paw edema caused by des-Arg(9)-BK, whereas they significantly inhibited BK-induced paw edema. Jointly, the results of the present study show that the edematogenic response mediated by the activation of B(1) receptors, in animals pre-treated with LPS, involves the release of tachykinins and CGRP, as well as serotonin, while NO and histamine seem not to be involved. Therefore, these data further support the notion that B(1) receptors have an important role in modulating the inflammatory processes.

Cyclooxygenase inhibitors attenuate bradykinin-induced vasoconstriction in septic isolated rat lungs

Cyclooxygenase (COX) products play an important role in modulating sepsis and subsequent endothelial injury. We hypothesized that COX inhibitors may attenuate endothelial dysfunction during sepsis, as measured by receptor-mediated bradykinin (BK)-induced vasoconstriction and/or receptor-independent hypoxic pulmonary vasoconstriction (HPV). Rats were administered intraperitoneally a nonselective COX inhibitor (indomethacin, 5 or 10 mg/kg) or a selective COX-2 inhibitor (NS-398, 4 or 8 mg/kg) 1 h before lipopolysaccharide (LPS, 15 mg/kg), or saline (control). Three hours later, the rats were anesthetized, the lungs were isolated, and pulmonary vasoreactivity was assessed with BK (0.3, 1.0, and 3.0 microg) and HPV (3% O(2)). Perfusion pressure was monitored as an index of vasoconstriction. To investigate what receptor-subtype is mediating BK responses, the BK(1)-receptor antagonist des-Arg(9)-[Leu(8)]-BK, the BK(2)-receptor antagonist HOE-140, or the thromboxane A(2)-receptor antagonist SQ 29548 (all at 1 microM) were added to the perfusate. BK-induced vasoconstriction was significantly increased in LPS lungs (1.4-5.2 mm Hg) compared with control (0.1-1.1 mm Hg). In LPS lungs, indomethacin 10 mg/kg significantly decreased BK vasoconstriction by 78% +/- 9%, whereas 5 mg/kg did not. NS-398, 4 mg/kg, significantly attenuated BK vasoconstriction at 0.3 microg (71% +/- 7%) and 1.0 microg (56% +/- 12%), whereas 8 mg/kg attenuated 0.3 microg BK (57% +/- 14%), compared with LPS lungs. HPV was increased in LPS lungs (21.5 +/- 2 mm Hg) compared with control lungs (9.8 +/- 0.6 mm Hg). Indomethacin 5 mg/kg increased HPV in LPS lungs; otherwise, HPV was not altered by COX inhibition. BK-induced vasoconstriction was prevented by BK(2), but not BK(1) or thromboxane A(2)-receptor antagonism. This study suggests that nonselective COX inhibition, and possibly inhibition of the inducible isoform COX-2, may attenuate sepsis-induced, receptor-mediated vasoconstriction in rats.

IMPLICATIONS

This study demonstrated that, in an isolated rat lung model, nonselective inhibition of the cyclooxygenase pathway, and possibly selective inhibition of the inducible cyclooxygenase-2 isoform, may attenuate sepsis-induced endothelial dysfunction.

In vivo B1 kinin-receptor upregulation. Evidence for involvement of protein kinases and nuclear factor kappaB pathways

1. Intradermal (i.d.) injection of cytokines, IL-1beta and TNFalpha (5 ng, 60 and 30 min prior) produces a rapid onset up-regulation of des-Arg9-BK-mediated rat paw oedema. Here we analyse the mechanisms involved in des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta or TNFalpha. 2. Co-injection of anti-IL-1beta, anti-TNFalpha and anti-IL-8 (50 ng) significantly inhibited des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta (65, 37 and 42%) or TNFalpha (39, 64, 25%). IL-1 receptor antagonist (IRA, 100 microg) or IL-10 (10 ng) inhibited the oedema caused by des-Arg9-BK, in rats that had received either IL-1beta (67 and 63%) or TNFalpha (46 and 35%). 3. Co-injection of the PKC inhibitors, staurosporine (10 nmol) or RO 318220 (30 nmol) inhibited des-Arg9-BK-induced paw oedema (44 and 42% for IL-1beta and, 53 and 30% for TNFalpha, respectively). Genistein (tyrosine kinase inhibitor, 2.5 mg kg-1, s.c.) or PD 098059 (MAP-kinase inhibitor, 30 nmol) produced marked inhibition of des-Arg9-BK-induced oedema (58 and 39% for IL-1beta and 31 and 35% for TNFalpha respectively). 4. The NF-kappaB inhibitors TLCK (2 mg kg-1, i.p.) and PDCT (100 mg kg-1, i.p.) significantly inhibited the oedema of des-Arg9-BK in IL-1beta (27 and 83%) or TNFalpha (28 and 80%) pre-treated animals. 5. It is concluded that up-regulation of B1 receptors modulated by IL-1beta or TNFalpha involves the release of other cytokines, activation of PKC and tyrosine kinase pathways, co-ordinated with the activation of MAP-kinase and nuclear factor kappaB, reinforcing the view that B1 receptors may exert a pivotal role in modulating chronic inflammatory processes.

Bradykinin down-regulates LPS-induced eosinophil accumulation in the pleural cavity of mice through type 2-kinin receptor activation: a role for prostaglandins

1. The role of both exogenously administered and endogenously generated bradykinin (BK) on LPS-induced eosinophil accumulation in the mice pleural cavity was investigated by means of treatment with BK selective receptor agonists/antagonists and captopril. 2. Intrathoracic (i.t.) injection of LPS (250 ng cavity(-1)) induced eosinophil influx at 24 h as previously described (Bozza et al., 1993). Pretreatment with the B1 receptor antagonist des-Arg9-[leu-8]BK (0.025 and 0.25 nmol cavity(-1)) showed no effect on this phenomenon, whereas pretreatment with the B2 receptor antagonists, NPC 17731 (0.025 and 0.25 nmol cavity(-1)) or HOE 140 (2.5 nmol cavity(-1)), increased LPS-induced eosinophil influx. Accordingly, pretreatment with captopril at 10 mg kg(-1) i.p., inhibited eosinophil infiltration induced by LPS in the pleural cavity, suggesting that endogenous BK is down-regulating LPS-induced eosinophil accumulation. 3. BK administered at 15 and 25 nmol cavity(-1), i.t. or i.p. also inhibited LPS-induced eosinophil accumulation. BK alone had no effect on the basal number of leucocytes in the pleural or peritoneal cavity in doses up to 25 nmol cavity(-1). Nevertheless, when injected at doses of 50 and 100 nmol cavity(-1) BK induced leucocyte influx characterized by neutrophil and eosinophil accumulation at 24 h. 4. Similarly to what was observed with BK, a specific B2 receptor agonist, Tyr8BK, administered at 0.25 nmol cavity(-1) i.p., significantly inhibited the eosinophil influx induced by LPS. 5. The mechanism by which B2 receptor agonists inhibit LPS-induced eosinophil accumulation was investigated by pretreating the animals with indomethacin or a selective cyclooxygenase-2 inhibitor, NS-398. Pretreatment with either indomethacin or NS-398 had no effect on eosinophil influx induced by LPS alone, but those drugs were able to restore the LPS-induced eosinophil influx in Tyr8BK (0.25 nmol cavity(-1)) injected mice. 6. In conclusion, endogenously generated bradykinin seems to modulate, through activation of B2 receptors, eosinphil accumulation induced by LPS via a mechanism dependent on prostanoid synthesis.

Role of kinin B1 and B2 receptors and mast cells in post intestinal infection-induced hypersensitivity to distension

Distension of the rat intestine causes a capsaicin-sensitive, pressure-dependent depressor response which is indicative of nociception. A hypersensitivity of jejunal distension which possibly involves tachykinin NK2 receptors and is restricted to areas with mast cell hyperplagia is observed in rats infected 30 days previously with Nippostrongylus brasiliensis. This study aimed to further investigate the role of mast cells, tachykinins and kinins in this intestinal hypersensitivity. The activity of a mast cell stabilizer (doxantrazole), kinin antagonists (des-Arg 10-[Leu9]-kallidin, B1, HOE 140, B2) and tachykinin antagonists (CP 99, 994, NK1, SR 142801, NK3) were tested against the distension-induced depressor responses in control and post-infected rats. The 30-day post-infection-induced hypersensitivity was significantly reduced by the mast cell stabilizer doxantrazole. The hypersensitivity had resolved in 90-day post-infected rats when mast cells levels had normalized. Des-Arg 10-[Leu9]-kallidin and HOE 140 did not inhibit the depressor responses in controls but produced a significant inhibition in 30-day post-infected rats. CP 99,994 inhibited the depressor responses in post-infected rats with an equal potency to that in control rats. SR 142801 was inactive in both groups. In conclusion, mast cells and kinin-mediated nociception appear to be involved in post-infection intestinal hypersensitivity whereas tachykinin NK1 and NK3 receptors do not.

Systemic treatment with Mycobacterium bovis bacillus Calmette-Guérin (BCG) potentiates kinin B1 receptor agonist-induced nociception and oedema formation in the formalin test in mice

This study investigates the effect and some of the mechanisms involved following systemic treatment of mice with Mycobacterium bovis bacillus Calmette-Guérin (BCG) (1 dose per animal containing 6.4 x 10(4) colony-forming units (CFu) 20-60 days beforehand) on modulation of the kinin B1 receptor agonist-induced nociception and oedema formation in the formalin test. Intraplantar (i.p.l.) co-injection of des-Arg9-bradykinin (4-32 nmol/paw) or des-Arg10-kallidin (1-15 nmol/paw), together with sub-maximal concentrations of formalin (0.01 or 0.5%), potentiated (P < 0.01) both pain phases and the paw oedema caused by formalin in animals pre-treated with saline. However, when animals were pre-treated with BCG, the dose-response curves for both B1 agonists were shifted 2 to 8-fold to the left. These B1-mediated effects peaked at 30-45 days after BCG treatment and were still elevated at 60 days after BCG injection. The pain response and oedema formation caused by i.p.l. co-injection of des-Arg9-bradykinin, together with formalin in BCG-pre-treated animals, were dose-dependently antagonised by i.p.l. co-injection of the B1 antagonist des-Arg9[Leu8]bradykinin (1-15 nmol/paw), but were not affected by the B2 antagonist Hoe 140 (10 nmol/paw). The i.p.l. co-injection of tyrosine8-bradykinin (a B2 agonist, 3-15 nmol/paw) with formalin (0.01 or 0.5%) potentiated the pain response and paw oedema in BCG and saline-pre-treated animals to the same extent (P < 0.01). The actions caused by tyrosine8-bradykinin were antagonised by Hoe 140, while des- Arg9[Leu8]bradykinin (10 nmol/paw) had no effect. Dexamethasone (0.5 mg/kg, s.c.), given every 24 h, from day 0 to 30-45, inhibited significantly the potentiation of nociceptive response and oedema formation caused by i.p.l. co-injection of formalin plus des-Arg9-bradykinin, while indomethacin (2 mg/kg, i.p.) or phenidone (30 mg/kg, i.p.), given 1 h prior, caused less inhibition. These data show that the long-term systemic treatment of mice with BCG produced dose-related potentiation of B1 receptor agonist-mediated nociception and oedema formation, without affecting similar responses caused by the B2 receptor agonist tyrosine8-bradykinin. Thus, systemic treatment of mice with BCG induces upregulation of B1 receptors, without affecting B2-mediated responses, by a mechanism that seems to be secondary to cytokine release.

Characterization of the receptor and the mechanisms underlying the inflammatory response induced by des-Arg9-BK in mouse pleurisy

1 The characterization of the B1 kinin receptor, and some mediators involved in the inflammatory response elicited by intrathoracic (i.t.) administration of des-Arg9-bradykinin (BK) in the mouse model of pleurisy, was investigated. 2 An i.t. injection of des-Arg9-BK (10-100 nmol per site), a selective B1 agonist, caused a significant and dose-related increase in the vascular permeability observed after 5 min, which peaked at 1 h, associated with an increase in cell influx, mainly neutrophils, and, to a lesser extent, mononuclear cell influx, peaking at 4 h and lasting for up to 48 h. The increase in fluid leakage caused by des-Arg9-BK was completely resolved 4 h after peptide injection. I.t. injection of Lys-des-Arg9-BK (30 nmol per site) caused a similar inflammatory response. 3 Both the exudation and the neutrophil influx elicited by i.t. injection of des-Arg9-BK were significantly antagonized (P<0.01) by an i.t. injection of the selective B1 antagonists des-Arg9-[Leu8]-BK (60 and 100 nmol per site) or des-Arg9-NPC 17731 (5 nmol per site), administered in association with des-Arg9-BK (P<0.01), or 30 and 60 min before the cellular peak, respectively. In contrast, an i.t. injection of the B2 bradykinin selective receptor antagonist Hoe 140 (30 nmol per site), at a dose which consistently antagonized bradykinin (10 nmol per site)-induced pleurisy, had no significant effect on des-Arg9-BK-induced pleurisy. 4 An i.t. injection of the selective tachykinin receptor antagonists (NK1) FK 888 (1 nmol per site), (NK2) SR 48968 (20 nmol per site) or (NK3) SR 142801 (10 nmol per site), administered 5 min before pleurisy induction, significantly antagonized neutrophil migration caused by i.t. injection of des-Arg9-BK. In addition, FK 888 and SR 142801, but not SR 48968, also prevented the influx of mononuclear cells in response to i.t. injection of des-Arg9-BK (P<0.01). However, the NK3 receptor antagonist SR 142801 (10 nmol per site) also significantly inhibited des-Arg9-BK-induced plasma extravasation. An i.t. injection of the calcitonin gene-related peptide (CGRP) receptor antagonist CGRP8-37 (1 nmol per site), administered 5 min before pleurisy induction, inhibited des-Arg9-BK-induced plasma extravasation (P<0.01), without significantly affecting the total and differential cell migration. 5 The nitric oxide synthase inhibitors L-NOARG and L-NAME (1 pmol per site), administered 30 min beforehand, almost completely prevented des-Arg9-BK (i.t.)-induced neutrophil cell migration (P<0.01), and, to a lesser extent, mononuclear cell migration (P<0.01). The D-enantiomer D-NAME had no effect on des-Arg9-BK-induced pleurisy. At the same dose range, L-NOARG and L-NAME inhibited the total cell migration (P<0.01). L-NAME, but not L-NOARG caused significant inhibition of des-Arg9-BK-induced fluid leakage. Indomethacin (1 mg kg(-1), i.p.), administered 1 h before des-Arg9-BK (30 nmol per site), inhibited the mononuclear cell migration (P<0.05), but, surprisingly, increased the neutrophil migration at 4 h without interfering with plasma extravasation. The administration of terfenadine (50 mg kg(-1), i.p.), 30 min before des-Arg9-BK (30 nmol per site), did not interfere significantly with the total cell migration or with the plasma extravasation in the mouse pleurisy caused by i.t. injection of des-Arg9-BK. 6 Pretreatment of animals with the lipopolysaccharide of E. coli (LPS; 10 microg per animal, i.v.) for 24 h did not result in any significant change of the inflammatory response induced by i.t. injection of des-Arg9-BK compared with the saline treated group. However, the identical treatment of mice with LPS resulted in a marked enhancement of des-Arg9-BK induced paw oedema (P<0.01). 7 In conclusion, we have demonstrated that the inflammatory response induced by i.t. injection of desArg9-BK, in a murine model of pleurisy, is mediated by stimulation of constitutive B1 receptors. (These responses are largely mediated by release of neuropeptides such as substanceP or CGRP and also by NO, but products derived from cyclo-oxygenase pathway and histamine seem not to be involved. Therefore, these results further support the notion that the B1 kinin receptor has an important role in modulating inflammatory responses, and it is suggested that selective B1 antagonists may provide therapeutic benefit in the treatment of inflammatory and allergic conditions.

Modulation of kinin B1 but not B2 receptors-mediated rat paw edema by IL-1beta and TNFalpha

The modulatory effects of IL-1beta and TNF alpha on the rat paw edema induced by B1 agonists have been analyzed. In naive rats, i.d. injection of B1 agonists, des-Arg9-bradykinin and des-Arg10-kallidin (up to 300 nmol), causes a minimal increase in paw volume, while the B2 agonist tyrosine8-bradykinin (0.3-10 nmol) induces graded paw edema. The injection of des-Arg9-bradykinin (10-100) nmol or des-Arg10-kallidin (1-100 nmol), in paws pre-treated with IL-1beta or TNF alpha (both 5 ng/paw; 60 and 30 min prior, respectively), caused a graded edema formation. The edemas induced by des-Arg9-bradykinin (100 nmol) were evident at 15 min, reaching the maximum 60 and 30 min after treatment with IL-1beta (0.64 +/- 0.06 ml) or TNF alpha (0.47 +/- 0.05 ml), respectively, being reduced at 360 min. The B1 antagonist des-Arg9-NPC 17731 (1-30 nmol), but not the B2 antagonist Hoe 140 (10 nmol), produced marked inhibition of des-Arg9-bradykinin-induced paw edema. Dexamethasone (0.5 mg/kg, s.c., 4 h) or cycloheximide (1.5 mg/kg, s.c., 6 h) significantly prevented the edema caused by des-Arg9-bradykinin (100 nmol) in rats treated with IL-1beta (81 +/- 5% and 59 +/- 3%) or TNF alpha (78 +/- 4% and 43 +/- 2%). Indomethacin (2 mg/kg, i.p.) or meloxicam (3 mg/kg, i.p.), 1 h prior, significantly reduced the edema induced by des-Arg9-bradykinin (100 nmol) in IL-1beta (40 +/- 6% and 69 +/- 8%) or TNF alpha (43 +/- 3% and 53 +/- 9%) treated rats. It is suggested that i.d. injection of the IL-1beta or TNF alpha, produced up-regulation of B1 receptor-mediated paw edema, being this effect sensitive to dexamethasone and cycloheximide and to cyclo-oxygenase pathway.