Acute angioedema in Cape Town emergency centres and a suggested algorithm to simplify and improve management

BACKGROUND

Angioedema is the most common acute allergic presentation to emergency centres (EC), with hospitalisation rates increasing in high-income countries. Angioedema can complicate with life-threatening laryngeal obstruction. There are no local data; therefore, we aimed to characterise acute angioedema cases presenting to ECs and develop a simple management algorithm.

OBJECTIVE

To characterise the clinical presentation, management and outcomes of acute angioedema cases presenting to ECs. Based on these findings, we developed a management algorithm for acute angioedema to improve the care of acute angioedema in South Africa (SA).

METHODS

We conducted a retrospective folder review of all patients admitted to Groote Schuur Hospital (tertiary) and Mitchells Plain District Hospital (secondary) ECs from 1  June 2018 to 31  June 2020. Using ICD-10 coding, folders of adults ≥18 years with possible angioedema presenting to the ECs were screened. An allergist extracted demographics, medical history, management and outcome data for each angioedema event.

RESULTS

A total of 142 acute angioedema episodes were included, with a median (interquartile range) age of 42 (28 - 58) years, and 62% of patients were female. The majority (124/142, 87%) of acute angioedema EC presentations involved swelling above the shoulders, with airway involvement in 20 (14%) patients, with two patients requiring intubation. Nineteen (13%) patients required admission, with five (26%) admitted to high care/intensive care. Drug-induced angioedema was the most common cause, with 64/142 (45%) linked to a known offending drug, 42/64 (65.6%) being angiotensin-converting enzyme inhibitor (ACE-I). Critical information to guide angioedema management, including past personal/family allergy history, and duration of angioedema prior to EC visit, was not recorded in 64.7% and 37.8% of EC records, respectively. Unnecessary treatment with corticosteroids or antihistamines occurred in 19/53 (36%) and 16/53 (30%) cases with bradykinin-mediated angioedema ACE-I angioedema and hereditary angioedema). Overall, only 36/142 (25%) of angioedema patients were connected to allergy care.

CONCLUSION

Angioedema is the most common allergy presentation to two ECs in Cape Town, SA. Bradykinin-mediated angioedema secondary to ACE-I therapy is the single most common offender, and was not appropriately managed in more than a third of cases. Based on these findings, we have developed a management algorithm that easily stratifies patients into bradykinin or mast cell-mediated angioedema with a step-by-step management approach that is applicable to the SA context. Ongoing awareness and education on allergy emergencies are required to ensure accurate diagnosis of less common causes of angioedema (particularly bradykinin-mediated angioedema) and linkage to allergy specialist care.

A case of acquired angioedema

ABSTRACT

Acquired angioedema is a rare disorder characterized by nonurticarial angioedema secondary to deficiency or altered activity of C1-esterase inhibitor protein. This article describes a patient whose recurrent angioedema was initially diagnosed as angiotensin-converting enzyme (ACE) inhibitor-induced angioedema. However, after further testing, she was diagnosed with acquired angioedema and subsequently treated with a synthetic bradykinin B2-receptor antagonist.

Management of hereditary angioedema in Japan: Focus on icatibant for the treatment of acute attacks

Hereditary angioedema (HAE) is characterized by unpredictable, recurring and painful swelling episodes that can be disabling or even life-threatening. Awareness of HAE has progressively grown worldwide, and options for treatment of acute attacks and prevention of future attacks continue to expand; however, unmet needs in diagnosis and treatment remain. In Japan, recognition of HAE within the medical community remains low, and numerous obstacles complicate diagnosis and access to treatment. Importance of timely treatment of HAE attacks with on-demand therapies is continually demonstrated; recommended agents per the WAO/EAACI treatment guidelines published in 2018 include C1 inhibitor (C1-INH) concentrate, ecallantide, and icatibant. In Japan, multiple factors contribute to delayed HAE treatment (potentially leading to life-threatening consequences), including difficulties in finding facilities at which C1-INH agents are readily available. Recognition of challenges faced in Japan can help promote efforts to address current needs and expand access to effective therapies. Icatibant, a potent, selective bradykinin B₂ receptor antagonist, has demonstrated inhibition of various bradykinin-induced biological effects in preclinical studies and has shown efficacy in treating attacks in various clinical settings (e.g. clinical trials, real-world studies), and HAE patient populations (e.g. with C1-INH deficiency, normal C1-INH). Icatibant was approved in Japan for the treatment of HAE attacks in September 2018; its addition to the HAE treatment armamentarium contributes to improved patient care. In Japan, disease awareness and education campaigns are warranted to further advance the management of HAE patients in light of the unmet needs and the emerging availability of modern diagnostic approaches and therapies.

[Update on perioperative hypersensitivity reactions: joint document from the Brazilian Society of Anesthesiology (SBA) and Brazilian Association of Allergy and Immunology (ASBAI) - Part II: etiology and diagnosis]

This second joint document, written by experts from the Brazilian Association of Allergy and Immunology (ASBAI) and Brazilian Society of Anesthesiology (SBA) concerned with perioperative anaphylaxis, aims to review the pathophysiological reaction mechanisms, triggering agents (in adults and children), and the approach for diagnosis during and after an episode of anaphylaxis. As anaphylaxis assessment is extensive, the identification of medications, antiseptics and other substances used at each setting, the comprehensive data documentation, and the use of standardized nomenclature are key points for obtaining more consistent epidemiological information on perioperative anaphylaxis.

Icatibant Outcome Survey in Patients with Hereditary Angioedema: Experience in Israel Compared with Other Countries

BACKGROUND

Management of patients with hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is evolving worldwide. Evaluating the Israeli experience may provide valuable insights.

OBJECTIVES

To compare demographics and icatibant treatment patterns and outcomes in patients with C1-INH-HAE enrolled in the Icatibant Outcome Survey (IOS) in Israel with those in other countries.

METHODS

The IOS is an ongoing observational study that prospectively monitors real-world icatibant safety/tolerability and treatment outcomes.

RESULTS

By July 2016, 58 patients from Israel and 594 patients from other countries were enrolled. Median age at diagnosis (16.7 vs. 21.3 years, P = 0.036) and median delay between symptom onset and diagnosis (0.8 vs. 6.6 years, P = 0.025) were lower in Israel compared with other countries, respectively. Differences in attack severity were not significant (P = 0.156); however, during follow-up, Israeli patients were less likely to miss > 7 days of work/school due to C1-INH-HAE-related complications (P = 0.007). A trend was also shown in Israel for earlier time to treatment (median 0.5 vs. 1.3 hours, P = 0.076), attack duration was shorter (median 5.0 vs. 9.0 hours, P = 0.026), and patients more often self-administered icatibant (97.2% vs. 87.5%, P = 0.003), respectively. However, Israeli patients were less likely to treat attacks (P = 0.036). Whereas patients in Israel reported exclusive use of danazol for long-term prophylaxis, those in other countries used various agents, including C1-INH.

CONCLUSIONS

Recognition of C1-INH-HAE and timeliness of icatibant treatment appear more favorable, and attack duration shorter, in Israel compared with other countries.

[EFFICACY, PHARMACOKINETICS, AND SAFETY OF ICATIBANT FOR THE TREATMENT OF JAPANESE PATIENTS WITH AN ACUTE ATTACK OF HEREDITARY ANGIOEDEMA: A PHASE 3 OPEN-LABEL STUDY]

BACKGROUND

Hereditary angioedema (HAE) is characterized by paroxysmal edema of the skin, gastrointestinal mucosa, and upper respiratory tract.

PURPOSE

This study investigated icatibant, a selective bradykinin B2 receptor antagonist, as treatment for Japanese patients with an acute HAE attack.

METHODS

This was an open-label, single-arm, Phase 3 study of Japanese adults with HAE type I or II. Icatibant (30 mg) was administered (by a healthcare professional [HCP] or self-administered) as a subcutaneous injection in the abdomen.

RESULTS

Eight patients (4 cutaneous, 3 abdominal, 1 laryngeal) were treated with icatibant (all single injection; 3 self-administered, 5 HCP-administered). The median time to onset of symptom relief was 1.75 hours (95% confidence interval, 1.00 to 2.50); all patients had onset of relief within 5 hours. The estimated time to maximum icatibant concentration in the circulation was 1.79 hours and the maximum concentration was 405 ng/mL. There were 3 patients who experienced 3 adverse events (2 HAE attacks and 1 headache); 7 patients experienced an injection site reaction.

CONCLUSION

Although our study was limited by the small number of patients, we found that icatibant was an effective and well-tolerated treatment for Japanese patients with acute HAE attacks, regardless of whether it was administered by a HCP or self-administered.

Evaluating satisfaction of patients with hereditary angioedema with their past and present treatments: Implications for future therapies

BACKGROUND

Ever-expanding armamentarium of treatments for hereditary angioedema (HAE) are associated with various adverse effects, issues with vascular access, or lack of self-administration.

OBJECTIVE

To understand patients' impressions and confidence in their past and present treatments, and identifying adverse events while also directly asking patients to reveal their hope for the future of HAE management and treatments.

METHODS

After institutional review board approval, all subjects with laboratory-confirmed HAE were mailed a survey that they completed and returned to the researchers, and data were collected and entered into a secure online web application for surveys. Medication confidence data were summarized and expressed as means, medians, standard deviations, and quartiles by using a 5-point Likert scale. Analyses were performed by using statistical software.

RESULTS

Of 150 surveys, 38 (25.3%) were completed. Among 36 subjects, 27 (75.0%) were female subjects, and the mean age was 50.1 years. Cinryze and Berinert (both C1-esterase inhibitors) had the highest median scores (5.0) for patient confidence, followed by ecallantide (4.5), icatibant (4.0), and androgens (2.0). For Cinryze, 64.3% selected it as the most effective and 57.1% tolerated it best. For Berinert, 50% of the subjects found it to be most effective and 59.1% tolerated it best. Some subjects listed androgens as most effective (33.3%) or best tolerated (16.7%), and many reported that this class caused the most adverse effects (44.4%). Among those who answered, 50% preferred a noninvasive method of administration, such as oral (24%), subcutaneous (18%), or not intravenous (8%) routes.

CONCLUSION

Determining patient predilections and the reasoning behind them can be valuable for determining specific therapies to achieve each individual's personal goals.

A randomized trial of icatibant in ACE-inhibitor-induced angioedema

BACKGROUND

Angioedema induced by treatment with angiotensin-converting-enzyme (ACE) inhibitors accounts for one third of angioedema cases in the emergency room; it is usually manifested in the upper airway and the head and neck region. There is no approved treatment for this potentially life-threatening condition.

METHODS

In this multicenter, double-blind, double-dummy, randomized phase 2 study, we assigned patients who had ACE-inhibitor-induced angioedema of the upper aerodigestive tract to treatment with 30 mg of subcutaneous icatibant, a selective bradykinin B2 receptor antagonist, or to the current off-label standard therapy consisting of intravenous prednisolone (500 mg) plus clemastine (2 mg). The primary efficacy end point was the median time to complete resolution of edema.

RESULTS

All 27 patients in the per-protocol population had complete resolution of edema. The median time to complete resolution was 8.0 hours (interquartile range, 3.0 to 16.0) with icatibant as compared with 27.1 hours (interquartile range, 20.3 to 48.0) with standard therapy (P=0.002). Three patients receiving standard therapy required rescue intervention with icatibant and prednisolone; 1 patient required tracheotomy. Significantly more patients in the icatibant group than in the standard-therapy group had complete resolution of edema within 4 hours after treatment (5 of 13 vs. 0 of 14, P=0.02). The median time to the onset of symptom relief (according to a composite investigator-assessed symptom score) was significantly shorter with icatibant than with standard therapy (2.0 hours vs. 11.7 hours, P=0.03). The results were similar when patient-assessed symptom scores were used.

CONCLUSIONS

Among patients with ACE-inhibitor-induced angioedema, the time to complete resolution of edema was significantly shorter with icatibant than with combination therapy with a glucocorticoid and an antihistamine. (Funded by Shire and the Federal Ministry of Education and Research of Germany; ClinicalTrials.gov number, NCT01154361.).

[Drug induced angioedema (ACE-inhibitors and other)]

Angiotensin Converting Enzyme inhibitors (ACE-I) use is a frequent cause of AE and must be suspected systematically in all patients with AE. The risk of AE is increased in: black people, transplanted patients, those who take gliptins or immunosuppressants (mTOR i). Angiotensin converting enzyme inhibitors induced angioedema (ACE-I AE) can occur a few days to several years after the beginning of this treatment and persist a few months after stopping it. ACE-I AE affect mainly the face and particularly the tongue but also the abdomen. ACE-I AE can be life threatening, due to the involvement of the tongue and the larynx. ACE-I AE must be treated as in the hereditary form when life threatening signs are present, with icatibant or C1 inhibitor concentrate. AE can occur in 10% of angiotensin receptor blockers (ARBs) treated patients who had developed ACE-I AE.

[Emergency management of bradykinin-mediated angioedema]

In the emergency setting, the diagnosis of bradykinin-mediated angioedema is based exclusively on history and physical examination. Severe attacks must be identified because the evolution is unpredictable with a risk of life-threatening airway obstruction. Underestimate the severity of the attack is a management pitfall to avoid. All attack under the shoulders should be considered as severe and must benefit from early specific treatment.

Icatibant, an inhibitor of bradykinin receptor 2, for hereditary angioedema attacks: prospective experimental single-cohort study

CONTEXT AND OBJECTIVE

Hereditary angioedema (HAE) with C1 inhibitor deficiency manifests as recurrent episodes of edema involving the skin, upper respiratory tract and gastrointestinal tract. It can be lethal due to asphyxia. The aim here was to evaluate the response to therapy for these attacks using icatibant, an inhibitor of the bradykinin receptor, which was recently introduced into Brazil.

DESIGN AND SETTING

Prospective experimental single-cohort study on the efficacy and safety of icatibant for HAE patients.

METHODS

Patients with a confirmed HAE diagnosis were enrolled according to symptoms and regardless of the time since onset of the attack. Icatibant was administered in accordance with the protocol that has been approved in Brazil. Symptom severity was assessed continuously and adverse events were monitored.

RESULTS

24 attacks in 20 HAE patients were treated (female/male 19:1; 19-55 years; median 29 years of age). The symptoms were: subcutaneous edema (22/24); abdominal pain (15/24) and upper airway obstruction (10/24). The time taken until onset of relief was: 5-10 minutes (5/24; 20.8%); 10-20 (5/24; 20.8%); 20-30 (8/24; 33.4%); 30-60 (5/24; 20.8%); and 2 hours (1/24; 4.3%). The time taken for complete resolution of symptoms ranged from 4.3 to 33.4 hours. Adverse effects were only reported at injection sites. Mild to moderate erythema and/or feelings of burning were reported by 15/24 patients, itching by 3 and no adverse effects in 6.

CONCLUSION

HAE type I patients who received icatibant responded promptly; most achieved improved symptom severity within 30 minutes. Local adverse events occurred in 75% of the patients.

Preclinical pharmacology, metabolic stability, pharmacokinetics and toxicology of the peptidic kinin B1 receptor antagonist R-954

We previously showed that R-954 (AcOrn[Oic(2),(αMe)Phe(5),dβNal(7),Ile(8)]desArg(9)-bradykinin) is a potent, selective and stable peptide antagonist of the inducible GPCR kinin B1 receptor. This compound shows potential applications for the treatment of several diseases, including cancer and neurological disturbances of diabetes. To enable clinical translation, more information regarding its pharmacological, pharmacokinetics (PK) and toxicological properties at preclinical stage is warranted. This was the principal objective of the present study. Herein, specificity of R-954 was characterized in binding studies on 133 human molecular targets to reveal minor cross-reactivities against the angiotensin AT2 and the bombesin receptors (110- and 330-fold lower affinity than for B1R, respectively). The pharmacokinetic of R-954 was studied in both normal and streptozotocin-diabetic anaesthetized rats providing half-lives of 1.9-2.7h. R-954 does not appear to be metabolized in the rat circulation and in several rat tissue homogenates, as the kidney, lung and liver. It appears to be excreted as parent drug in the bile (21%) and in urine. A preliminary toxicological profile of R-954 was obtained in rats under various administration routes. R-954 appears to be well tolerated. Overall, these results indicate that R-954 exhibits favorable preclinical pharmacological/PK characteristics and encouraging safety profiles, suitable for early studies in humans.

Lump in the throat - a case study

Jack, aged 66 years, presented to his general practitioner with a foreign body sensation in his throat and altered voice, which developed over 30 minutes. He was otherwise well, having no other new symptoms or recent alterations to medication. He had not eaten anything unusual. He had hypertension, type 2 diabetes, stable ischaemic heart disease, urolithiasis and benign prostatic hypertrophy. His regular medication was metformin, rosuvastatin, carvedilol, candesartan (last 5 years) and saxagliptin (last 6 months). He had no allergies but was intolerant of ramipril due to cough. There was no family history of note. On examination he had no itch or rash, or swelling of the tongue, lips, cheek or neck. However, there was oedema of the soft palate and uvula. He was maintaining his airway, saturating at 98%, and his chest was clear. He was afebrile and systemically well.

Hereditary angioedema therapies in the United States: movement toward an international treatment consensus

BACKGROUND

Hereditary angioedema (HAE) is a rare, potentially life-threatening autosomal dominant disease characterized by recurrent angioedema attacks that affect the skin, gastrointestinal tract, and airway, including the larynx. Pharmacologic developments in HAE treatment have culminated in the recent introduction of 4 new HAE-specific therapies in the United States.

OBJECTIVES

In light of these new therapeutic options, this commentary outlines historical US HAE therapy choices, discusses the potential effect of the 4 recently approved HAE treatments, and considers strategies for optimizing their use in line with international treatment recommendations.

DISCUSSION

Treatment options for HAE in the United States have been limited to attenuated androgens and antifibrinolytic agents for long-term prophylaxis and FFP and supportive therapy for the management of acute attacks. The 4 new therapies that have recently become available (ie, 2 plasma-derived C1 esterase inhibitor (C1-INH) concentrates, the kallikrein inhibitor ecallantide, and the bradykinin β(2)-antagonist icatibant) have provided an opportunity to change routine HAE treatment. In 2009, despite the availability of 2 of the new treatments (ie, the plasma-derived C1-INH concentrates), a large survey of US physicians suggested that wide variability still existed in the treatment of patients with HAE. Since this survey was undertaken, clinical experience with all 4 new treatments has increased significantly, and because 3 of these agents (ie, 2 plasma-derived C1-INH concentrates and icatibant) can be self-administered by trained patients, physicians can now provide individualized care that is proven effective and more aligned with international guidance.

Evidence-based recommendations for the therapeutic management of angioedema owing to hereditary C1 inhibitor deficiency: consensus report of an International Working Group

Angioedema owing to hereditary deficiency of C1 inhibitor (HAE) is a rare, life-threatening, disabling disease. In the last 2 years, the results of well-designed and controlled trials with existing and new therapies for this condition have been published, and new treatments reached the market. Current guidelines for the treatment for HAE were released before the new trials and before the new treatments became available and were essentially based on observational studies and expert opinion. To provide evidence-based HAE treatment guidelines supported by the new studies, a conference was held in Gargnano del Garda, Italy, from September 26 to 29, 2010. The meeting hosted 58 experienced HAE expert physicians, representatives of pharmaceutical companies and representatives of HAE patients' associations. Here, we report the topics discussed during the meeting and evidence-based consensus about management approaches for HAE in adult/adolescent patients.

Consensus statement on the diagnosis, management, and treatment of angioedema mediated by bradykinin. Part I. Classification, epidemiology, pathophysiology, genetics, clinical symptoms, and diagnosis

BACKGROUND

There are no Spanish guidelines or consensus statement on bradykinin-induced angioedema.

AIM

To review the pathophysiology, genetics, and clinical symptoms of the different types of bradykinin-induced angioedema and to draft a consensus statement in light of currently available scientific evidence and the experience of experts. This statement will serve as a guideline to health professionals.

METHODS

The consensus was led by the Spanish Study Group on Bradykinin-Induced Angioedema (SGBA), a working group of the Spanish Society of Allergology and Clinical Immunology. A review was conducted of scientific papers on different types of bradykinin-induced angioedema (hereditary and acquired angioedema due to C1 inhibitor deficiency, hereditary angioedema related to estrogens, angioedema induced by angiotensin-converting enzyme inhibitors). Several discussion meetings of the SGBA were held in Madrid to reach the consensus.

RESULTS

The pathophysiology, genetics, and clinical symptoms of the different types of angioedema are reviewed. Diagnostic approaches are discussed and the consensus reached is described.

CONCLUSIONS

A review of bradykinin-induced angioedema and a consensus on diagnosis are presented.

Icatibant. Attacks of hereditary angioedema: continue to use C1 esterase inhibitor

Hereditary angioedema is a severe genetic disorder due to C1 esterase inhibitor deficiency, which leads to an excess of bradykinin. It is characterised by attacks of subcutaneous or mucosal oedema, which can carry a risk of asphyxiation if the larynx is involved. The first-choice symptomatic treatment for attacks is intravenous C1 esterase inhibitor administration. Tranexamic acid is sometimes used. Icatibant, a decapeptide bradykinin B2 receptor antagonist, is now authorised in the European Union for use in this situation. We found no trials comparing icatibant versus C1 esterase inhibitor. The two principal clinical trials were both comparative trials, one versus tranexamic acid (74 patients), and the other versus placebo (56 patients). No mortality data were reported in either trial. Icatibant seemed to be more effective than tranexamic acid in relieving symptoms and also yielded a higher response rate. However, these positive results were not confirmed in the placebo-controlled trial. Both trials suffer from several biases, ruling out firm conclusions on the efficacy of icatibant, the trials were underpowered, some criteria were difficult to measure, the blinding was incomplete, and tranexamic acid was given at a lower dose than that recommended. The main adverse effects of icatibant are reactions at the injection site, which occur in almost all patients. A potential risk of cardiac disorders (especially angina) needs to be investigated. Subcutaneous administration of icatibant requires a large volume of solution (3 ml). In practice, in the absence of head-to-head comparisons, it remains to be shown whether or not icatibant has a better risk-benefit balance than C1 esterase inhibitor. Due to inconsistencies between the results and numerous biases in the two main clinical trials, the evidence supporting the efficacy of icatibant is weak. C1 esterase inhibitor remains the first-choice treatment for patients with acute attacks of hereditary angioedema.

Icatibant, a new bradykinin-receptor antagonist, in hereditary angioedema

BACKGROUND

Hereditary angioedema is characterized by recurrent attacks of angioedema of the skin, larynx, and gastrointestinal tract. Bradykinin is the key mediator of symptoms. Icatibant is a selective bradykinin B2 receptor antagonist.

METHODS

In two double-blind, randomized, multicenter trials, we evaluated the effect of icatibant in patients with hereditary angioedema presenting with cutaneous or abdominal attacks. In the For Angioedema Subcutaneous Treatment (FAST) 1 trial, patients received either icatibant or placebo; in FAST-2, patients received either icatibant or oral tranexamic acid, at a dose of 3 g daily for 2 days. Icatibant was given once, subcutaneously, at a dose of 30 mg. The primary end point was the median time to clinically significant relief of symptoms.

RESULTS

A total of 56 and 74 patients underwent randomization in the FAST-1 and FAST-2 trials, respectively. The primary end point was reached in 2.5 hours with icatibant versus 4.6 hours with placebo in the FAST-1 trial (P=0.14) and in 2.0 hours with icatibant versus 12.0 hours with tranexamic acid in the FAST-2 trial (P<0.001). In the FAST-1 study, 3 recipients of icatibant and 13 recipients of placebo needed treatment with rescue medication. The median time to first improvement of symptoms, as assessed by patients and by investigators, was significantly shorter with icatibant in both trials. No icatibant-related serious adverse events were reported.

CONCLUSIONS

In patients with hereditary angioedema having acute attacks, we found a significant benefit of icatibant as compared with tranexamic acid in one trial and a nonsignificant benefit of icatibant as compared with placebo in the other trial with regard to the primary end point. The early use of rescue medication may have obscured the benefit of icatibant in the placebo trial. (Funded by Jerini; ClinicalTrials.gov numbers, NCT00097695 and NCT00500656.)

Hereditary angioedema: new hopes for an orphan disease

Hereditary angioedema is a rare genetic disorder, manifested by recurrent edema leading to disfigurement, organ dysfunction and life-threatening respiratory impairment that may become fatal. The hallmark of HAE is C1 esterase inhibitor deficiency, but recent evidence points at bradykinin as the main mediator that causes hyperpermeability of small vasculature, leading to accumulation of edema fluid. Current therapeutic options for HAE are limited, and consist of drugs, replacement therapy, and supportive treatment. In view of many disadvantages of the current therapeutic modalities, new approaches to the treatment of HAE are now being offered. This review summarizes our experience with a new line of medications developed for the treatment of acute exacerbations and prophylaxis of HAE--icatibant: bradykinin receptor antagonist, ecallantide: kallikrein inhibitor, and two C1 INH preparations: Berinert-P, human plasma-derived concentrate, and Rhucin: novel recombinant C1-INH produced in transgenic rabbits. Preliminary results of these studies are encouraging and may bring new hope to the patients with this distressing condition. The exact number of HAE patients in Israel is unknown and because patients are treated individually and comprehensive laboratory assessment is partial, many cases might be missed or not treated according to accepted guidelines. We offer a new specialty center for HAE patients, addressing the medical and psychosocial needs of patients and their families.

Neuronal activation at the spinal cord and medullary pain control centers after joint stimulation: a c-fos study in acute and chronic articular inflammation

Chronic inflammatory pain induces short- and long-term central changes, which have been mainly studied at the spinal cord level. Supraspinal pain control centers intrinsically connected with the dorsal horn are also prone to be affected by chronic inflammatory pain. C-fos expression was used as a neuronal activation marker at spinal and supraspinal levels to i) compare acute and chronic articular inflammation, and ii) analyze the effects of brief innocuous or noxious stimulation of a chronically inflamed joint. Acute articular inflammation was induced by an inflammatory soup with prostaglandin E(2) and bradykinin, both at 10(-5) M. Chronic articular inflammation consisted of 14 days of monoarthritis. Early c-fos expression was studied 4 min after inflammatory soup injection or stimulation of the arthritic joint whereas late c-fos expression was evaluated 2 h after those stimuli. At the spinal cord, the analysis was focused on the dorsal horn (laminae I-V) and supraspinally, five major regions of the endogenous pain control system were considered: the caudal ventrolateral medulla (VLM), the dorsal reticular nucleus (DRt), the ventral reticular nucleus (VRt), the nucleus of the solitary tract (Sol) and the rostroventromedial medulla (RVM). Acute articular inflammation induced early and late increases in c-fos expression at the spinal level and late increases supraspinally whereas the effects of monoarthritis were more moderate and restricted to the spinal cord. When monoarthritic animals were subjected to gentle touch or bending of the joint, early increases in c-fos expression were detected supraspinally, but not at the spinal level. In this region, noxious mechanical stimulation induced late increases in non-inflamed animals and both early and late increases in monoarthritic rats. Supraspinally, noxious stimulation induced only late increases in c-fos expression. The present results show complex differences in the patterns of c-fos expression between the spinal cord and medullary areas of the pain control system during articular inflammation, which indicate that the somatosensory system is differentially affected by the installation of chronic pain.

Gastrocardiac afferent convergence in upper thoracic spinal neurons: a central mechanism of postprandial angina pectoris

The aim of this study was to examine whether gastric afferent information converged onto upper thoracic spinal neurons that received noxious cardiac input. Extracellular potentials of single upper thoracic (T3) spinal neurons were recorded in pentobarbital-anesthetized, paralyzed, ventilated male rats. Gastric distension (GD) (20, 40, 60 mm Hg, 20 seconds) was produced by air inflation of a latex balloon surgically placed in the stomach. A catheter was placed in the pericardial sac to administer bradykinin solution (10 microg/mL, 0.2 mL, 1 minute) as a noxious cardiac stimulus. Noxious GD (> or =40 mm Hg) altered activity of 26 of 31 (84%) spinal neurons receiving cardiac input. Twenty-two (85%) gastrocardiac convergent neurons were excited, and 1 neuron was inhibited by both intrapericardial bradykinin and GD; the remainder exhibited biphasic response patterns. Twenty-three of 26 (88%) gastrocardiac neurons also received convergent somatic input from the chest, triceps, and upper back areas. Bilateral cervical vagotomy did not significantly affect excitatory responses to GD in 5 of 5 neurons tested. Spinal transection at the C1 segment after vagotomy did not affect excitatory responses to GD in 3 of 4 neurons but abolished the GD response in 1 neuron. These data showed that a gastric stimulus excited T3 spinal neurons with noxious cardiac input primarily by way of intraspinal ascending pathways.

PERSPECTIVE

Convergence of gastric afferent input onto upper thoracic spinal neurons receiving noxious cardiac input that was observed in the present study may provide a spinal mechanism that explains stomach-heart cross-organ communication, such as postprandial triggering and worsening of angina pectoris in patients with coronary artery disease.

Bradykinin- and substance P-induced edema formation in the hamster cheek pouch is tyrosine kinase dependent

The purpose of this study was to determine whether protein tyrosine kinase, a ubiquitous family of intracellular signaling enzymes that regulates endothelial cell function, modulates bradykinin- and substance P-induced increase in macromolecular efflux from the intact hamster cheek pouch microcirculation. Using intravital microscopy, I found that suffusion of bradykinin or substance P (each, 0.5 and 1.0 microM) onto the cheek pouch elicited significant, concentration-dependent leaky site formation and increase in clearance of fluorescein isothiocyanate-dextran (FITC-dextran; molecular mass, 70 kDa; P < 0.05). These responses were significantly attenuated by suffusion of genistein (1.0 microM) or tyrphostin 25 (10 microM), two structurally unrelated, nonspecific protein tyrosine kinase inhibitors (P < 0.05). Conceivably, the kinase(s) involved in this process could be agonist specific because genistein was more effective than tyrphostin 25 in attenuating bradykinin-induced responses while the opposite was observed with substance P. Both inhibitors had no significant effects on adenosine (0.5 M)-induced responses (P > 0.5). Collectively, these data suggest that the protein tyrosine kinase metabolic pathway modulates, in part, the edemagenic effects of bradykinin and substance P in the intact hamster cheek pouch microcirculation in a specific fashion.

Treatment of acute edema attacks in hereditary angioedema with a bradykinin receptor-2 antagonist (Icatibant)

BACKGROUND

In hereditary angioedema, bradykinin is assumed to be the most important mediator of edema formation.

OBJECTIVE

To assess whether the selective bradykinin receptor-2 antagonist Icatibant is effective in acute edema attacks of hereditary angioedema.

METHODS

In this uncontrolled pilot study, 15 patients with 20 attacks were treated with Icatibant. The attacks were analyzed by using a standardized and validated visual analog scale measurement and compared with historical data of untreated attacks. Plasma bradykinin concentration was measured before and 4 hours after intravenous Icatibant treatment.

RESULTS

Symptom intensity decreased within 4 hours after administration of Icatibant; the median time to onset of symptom relief was 1.50, 1.42, and 1.13 hours in the intravenous groups and 0.58 and 0.45 hours in the subcutaneous groups, respectively. The median difference in the 10-cm visual analog scale 4 hours after start of treatment was 4.11 cm (95% CI, 1.72-6.07). Compared with untreated attacks, Icatibant treatment reduced the mean (SD) time to onset of symptom relief by 97% from 42 +/- 14 to 1.16 +/- 0.95 hours (all groups combined). Median bradykinin concentration was 7-fold above the norm during acute attacks at 48.5 pmol/L and decreased to 18.0 pmol/L 4 hours after Icatibant infusion or injection.

CONCLUSION

Icatibant was effective in treating acute attacks of hereditary angioedema.

CLINICAL IMPLICATIONS

This is the first report demonstrating the clinical usefulness of antagonizing bradykinin binding to bradykinin receptor-2 in hereditary angioedema.

Evidence of anti-inflammatory effects of Passiflora edulis in an inflammation model

The popular medicine Passiflora edulis has been used as a sedative, tranquilizer, against cutaneous inflammatory diseases and intermittent fever. Most of the pharmacological investigations of Passiflora edulis have been addressed to its Central Nervous System activities, such as anxiolytic, anticonvulsant and sedative actions. Otherwise, there are few reports about the anti-inflammatory activity of the Passiflora species. The aim of this study was to investigate the mechanism of the anti-inflammatory effect of aqueous lyophilized extract obtained from leaves of Passiflora edulis var. flavicarpa Degener (Passifloraceae) in the mouse model of pleurisy induced by carrageenan (Cg), bradykinin, histamine or substance P, observing the effects upon leucocytes migration, myeloperoxidase (MPO), nitric oxide (NO) concentrations and tumor necrosis factor-alpha (TNFalpha) and interleukin-1 beta (IL-1beta) levels.

RESULTS

Passiflora edulis (250mg/kg) administered by intraperitoneal route (i.p.) inhibited the leukocyte, neutrophils, myeloperoxidase, nitric oxide, TNFalpha and IL-1beta levels (P<0.01) in the pleurisy induced by carrageenan. Passiflora edulis (250-500mg/kg, i.p.) also inhibited total and differential leukocytes in the pleurisy induced by bradykinin, histamine or substance P (P<0.05).

CONCLUSION

Several mechanisms, including the inhibition of pro-inflammatory cytokines (TNFalpha, IL-1beta), enzyme (myeloperoxidase) and mediators (bradykinin, histamine, substance P, nitric oxide) release and/or action, appear to account for Passiflora edulis's actions.

Modulation of hypotensive effects of kinins by cathepsin K

Kinins are pro-inflammatory peptides, which participate in the maintenance of cardiovascular homeostasis, and play a key role in numerous diseases, including lung fibrosis and hypertension. Evidence has been provided recently for the presence of alternative mechanisms of bradykinin generation and/or degradation. Here we showed that cathepsin K may act as a potent kinin-degrading enzyme in bloodstream. Contrary to cathepsin L, cathepsin K attenuates kallikrein-induced decrease of rat blood pressure, and reduces the hypotensive effect of bradykinin in a dose-dependent manner. Moreover, we identified, by engineering the S2 subsite of both recombinant enzymes, two critical residues involved respectively in the kininase activity of cathepsin K, i.e. Tyr67/Leu205, versus kininogenase activity of cathepsin L, i.e. Leu67/Ala205. In conclusion, according to its ability to modulate hypotensive effects of kinins, we propose that cathepsin K is a kininase of biological relevance, in complement of well-documented neutral endopeptidase or angiotensin-converting enzyme.

Evaluation and management of angioedema of the head and neck

PURPOSE OF REVIEW

Sudden occurrence of subcutaneous or submucosal swelling, the so-called angioedema, is an established and potentially life-threatening condition. Several forms of angioedema show a great variety of tissue localizations and different underlying mechanisms such as genetic mutations, allergic reactions and nonallergic reactions exist. Unfortunately, angioedema is often unrecognized and/or incorrectly treated. To change this situation, a better understanding of angioedema and possible therapeutic approaches appears necessary.

RECENT FINDINGS

Recent investigations have shed new light on the pathomechanism of nonallergic drug-induced angioedema and new therapeutic options targeting the kallikrein-kinin system have become available for patients in clinical trials. Furthermore, extensive clinical evaluations of commonly used inhibitors of the renin-angiotensin system have provided reliable data on the incidence of angioedema induced by these drugs. Accordingly, several thousand patients worldwide experience severe fatal attacks although timely medical care would have saved their lives.

SUMMARY

Current data suggest that the nonapetide bradykinin plays a crucial role in the pathogenesis of most forms of nonallergic angioedema, while histamine acts as the main biogenic mediator in allergic angioedema. Thus, correct diagnosis is crucial for effective treatment. Standard antiallergic drugs such as glucocorticoids and antihistamines are most probably ineffective in nonallergic angioedema forms.

Phase II trial of intravenous lobradimil and carboplatin in childhood brain tumors: a report from the Children’s Oncology Group

BACKGROUND

[corrected] Lobradimil is a synthetic bradykinin analog that rapidly and transiently increases the permeability of the blood-brain barrier (BBB). The combination of lobradimil and carboplatin was studied in pediatric patients with primary brain tumors in a phase II trial, the primary endpoints of which were to estimate the response rate and time to disease progression.

PATIENTS AND METHODS

Patients were stratified by histology into five cohorts: brainstem glioma, high-grade glioma, low-grade glioma, medullobastoma/primitive neuroectodermal tumor (PNET), and ependymoma. Patients received carboplatin adaptively dosed to achieve a target AUC of 3.5 mg min/ml per day (7 mg.min/ml/cycle) intravenously over 15 min on 2 consecutive days and lobradimil 600 ng/kg ideal body weight/day on 2 consecutive days each 28 day cycle.

RESULTS

Forty-one patients, age 2-19 years, were enrolled; 38 patients, including 1 patient ultimately determined to have atypical neurocytoma, were evaluable for response. No objective responses were observed in the brainstem glioma (n=12) and high-grade glioma (n = 9) cohorts, although two patients with high-grade glioma had prolonged disease stabilization (>6 months). The study was closed for commercial reasons prior to achieving the accrual goals for the ependymoma (n = 8), medulloblastoma/PNET (n = 6) and low-grade glioma (n = 2) cohorts, although responses were observed in 1 patient with PNET and 2 patients with ependymoma.

CONCLUSION

The combination of lobradimil and carboplatin was inactive in childhood high-grade gliomas and brainstem gliomas.

Phase 1 study of concurrent RMP-7 and carboplatin with radiotherapy for children with newly diagnosed brainstem gliomas

BACKGROUND

Ninety percent of children with diffuse intrinsic brainstem tumors will die within 18 months of diagnosis. Radiotherapy is of transient benefit, and one way to potentially improve its efficacy is to add radiosensitizers. Carboplatin is antineoplastic and radiosensitizing. However, delivery to the primary tumor site is problematic. RMP-7 is a bradykinin analog that causes selective permeability of the blood-brain-tumor interface. The goal of the current Phase I study was to determine the toxicity and feasibility of delivering RMP-7 and carboplatin for 5 successive days during radiotherapy.

METHODS

RMP-7 was given before the end of carboplatin infusion. Local radiotherapy (5940 centigrays) was given within 4 hours of completion of drug delivery. Duration of treatment was escalated in a stepwise, weekly fashion, in cohorts of 3, until there was treatment-limiting toxicity or until radiotherapy was completed. Thirteen patients were treated, whose median age was 7 years (range, 3-14 yrs).

RESULTS

One child died early in treatment of progressive disease and was not assessable for toxicity. Treatment for 3, 4, or 5 weeks was tolerated well, with mild flushing, tachycardia, nausea, emesis, dizziness, and abdominal pain. Of 3 children treated at the full duration of therapy (33 doses over 7 wks), 1 developed dose-limiting hepatotoxicity and neutropenia. The estimated median survival period was 328 days, and 1 patient remained disease progression free > 400 days from initiation of treatment.

CONCLUSIONS

The results of the current study confirmed the feasibility of giving RMP-7 and carboplatin daily during radiotherapy.

Sexual dimorphism in the effect of nonhabituating stress on neurogenic plasma extravasation

The sympathoadrenal axis contributes to the sexual dimorphism of the inflammatory response. As stress both activates the sympathoadrenal axis and profoundly affects inflammation and inflammatory disease, we evaluated whether stress exerts a sexually dimorphic effect on a major component of the inflammatory response, plasma extravasation. We evaluated the effect of a nonhabituating stress, repeated intermittent sound (30 min/day for 4 days), on neurogenic synovial plasma extravasation, induced by bradykinin in the rat knee joint. Sound stress profoundly inhibited bradykinin-induced plasma extravasation in male rats, but profoundly enhanced it in female rats. These effects took 24 h to fully develop after the last exposure to stress. In gonadectomized males, bradykinin-induced plasma extravasation was lower than intact males, and sound stress now enhanced it, i.e. gonadectomized males were phenotypically like intact females. In gonadectomized females, bradykinin-induced plasma extravasation was greater than in intact adult females, and sound stress still enhanced it. Adrenal enucleation significantly attenuated the effect of sound stress on bradykinin-induced plasma extravasation in both male and female rats. We tested the hypothesis that these effects of sound stress were due to sustained enhanced plasma levels of stress hormones. Corticosterone and epinephrine, only when administered in combination, over five days, produced a qualitatively similar effect as sound stress, i.e. bradykinin-induced plasma extravasation was significantly decreased in males and increased in females. These findings suggest that a combined effect of the hypothalamic-pituitary adrenal and sympathoadrenal stress axes are responsible for the marked sexual dimorphism in the effect of stress on the inflammatory response.

Erythema marginatum and hereditary angioedema

OBJECTIVE

To search for anaphylatoxin activity in plasma during episodes of erythema marginatum, and to evaluate the histology of erythema marginatum by electron microscopy and immunohistologic techniques.

METHODS

Plasma samples were studied for C5a activity by granulocyte aggregation, and C3 conversion by immunoelectrophoresis. A skin biopsy of erythema marginatum was done, and the tissue stained with a rabbit antibody to bradykinin.

RESULTS

No plasma anaphylatoxin was found. Dense deposits of bradykinin were discovered in stromal tissue and lining endothelial cells.

CONCLUSIONS

Bradykinin may be important in the causality of the erythema marginatum associated with hereditary angioedema.

Bradykinin preconditioning in coronary artery bypass grafting

BACKGROUND

Experimental studies have shown that activation of bradykinin B2 receptor is one of the most important triggers of ischemic preconditioning. However, the effect of exogenous administration of bradykinin in cardiac surgery is not yet known. The present prospective randomized study was designed to investigate the effect of bradykinin pretreatment in patients undergoing elective coronary artery bypass surgery.

METHODS

Forty-one patients with multiple-vessel coronary artery disease and stable angina, admitted for the first time for elective coronary artery bypass surgery, were randomized into control or bradykinin (BK) groups. Patients in the BK group received bradykinin infusion for 7 minutes (total dose 25 microg) before the initiation of cardiopulmonary bypass. Perioperative cardiac specific troponin I (cTnI) and creatine kinase cardiac isoenzyme (CKMB) release and hemodynamics were recorded.

RESULTS

Bradykinin infusion caused acute decrease of blood pressure in most of the cases and the mean minimum mean blood pressure during bradykinin infusion was 72.7% of the original mean blood pressure (MBP) level (74.7 +/- 7.9 vs 54.4 +/- 12.1 mm Hg, p < 0.01). There were no differences in baseline levels of cTnI and CKMB between the groups. The postoperative cTnI levels were lower than 10 ng/mL in most patients in both groups (18 in the BK group and 15 in the control group). There was no difference in cTnI between the groups. However, patients who received bradykinin released significantly less CKMB than did the controls postoperatively (6 hours, BK, 22.1 +/- 9.5 vs control, 23.6 +/- 12.7 U/L; 12 hours, BK, 19.4 +/- 12.4 vs control, 28.7 +/- 23.8 U/L; 24 hours, BK, 21.5 +/- 14.7 vs control, 35.5 +/- 28.9 U/L; 48 hours, BK, 14.4 +/- 7.5 vs control, 23.5 +/- 13.6 U/L; analysis of variance [ANOVA] for repeated measurement, p = 0.036). Maximum CKMB was also lower in the BK group (22.4 +/- 14.4 vs 37.7 +/- 27.5 U/L, p = 0.044). There was no significant difference between the groups in any of the hemodynamic variables.

CONCLUSIONS

Exogenous bradykinin infusion showed weak cardioprotective effect in the low-risk patients undergoing coronary artery bypass surgery but the dose used in the study caused acute decrease of systemic blood pressure.

Icatibant: HOE 140, JE 049, JE049

Icatibant [HOE 140, JE 049] is a potent, specific and selective peptidomimetic bradykinin beta2-receptor antagonist. It has a modified peptide structure, and is the first bradykinin receptor antagonist to act on the guinea-pig trachea without demonstrating agonist effects. Icatibant was originated by Hoechst Marion Roussel (now Sanofi-Aventis). Jerini is seeking a partner for development and marketing of icatibant for the treatment of refractory ascites in liver cirrhosis, angioedema and burns. In August 2004, Aventis merged with Sanofi-Synthelabo to form Sanofi-Aventis.Icatibant has shown an excellent safety profile in phase I studies. In December 2003, Jerini demonstrated positive results in the phase IIa study. Results obtained were statistically significant and clinically relevant. At the BIO 2004 International Annual Convention (BIO-2004) [San Francisco, CA, USA; 6-9 June 2004], Jerini reported plans to initiate phase IIb trials in this indication in the second half of 2004. Positive results from an icatibant formulation comparative study, in patients with acute attacks of hereditary angioedema, were announced in August 2004; IV and SC formulations showed no difference in efficacy and safety. It was announced in September 2004 by Jerini that a pivotal study, known as For Angioedema Subcutaneous Treatment (FAST) 1, had been initiated in the US and Canada. The protocol of a European study, to be known as FAST 2, is to be submitted to the authorities in September 2004. Jerini expects to launch the product in 2006. The US FDA granted icatibant, for the treatment of hereditary angioedema, fast-track designation in July 2004. In January 2003, the European Agency for the Evaluation of Medicinal Products granted icatibant orphan drug status in Europe for the treatment of angioedema. In November 2003, Jerini announced that effective December 2003, icatibant had orphan drug status in the US for the same indication.

Involvement of nitric oxide and prostaglandin pathways in the cardioprotective actions of bradykinin in rats with experimental myocardial infarction

Bradykinin is a potent endothelium-dependent vasodilator in the coronary vascular bed. Endothelial mediators released by bradykinin include nitric oxide, prostacyclin and as yet unidentified endothelium-derived hyperpolarising factors. We wished to determine the involvement of nitric oxide and prostaglandin pathways in the cardioprotective actions mediated by bradykinin via the combined inhibition of ACE and aminopeptidase P (APP) in an in vivo rat model of acute ischemia (30 min) and reperfusion (4h). Myocardial infarct size was measured by using the staining agent 2,3,5-triphenyl tetrazolium chloride (TTC). Lipid peroxide levels in serum and in heart tissue were estimated spectrophotometrically. A lead II electrocardiogram was monitored at various intervals throughout the experiment. Infarct size reduction obtained with the combined inhibition of enalapril and apstatin, lisinopril and apstatin was blocked partially but significantly with the prior administration of L-NAME (Nomega-nitro-L-arginine methyl ester) or aspirin, suggesting the involvement of both nitric oxide and prostaglandin pathways in the cardioprotective actions mediated by bradykinin.

Repeated, non-habituating stress suppresses inflammatory plasma extravasation by a novel, sympathoadrenal dependent mechanism

The mechanism by which chronic stress affects the course of inflammatory diseases is still not well understood. We have evaluated the effect of two types of nonhabituating stress on a major component of the inflammatory response, synovial plasma extravasation, induced by perfusion of the potent inflammatory mediator, bradykinin and evaluated the underlying neuroendocrine mechanism in the rat. Chronic intermittent noise or ether stress induced profound inhibition of bradykinin-induced plasma extravasation, which is associated with increased adjuvant-arthritis severity. This inhibition, however, took 24 h to fully develop after the last exposure to stress and persisted for at least 48 h. The inhibition could be reversed by an additional exposure to the stressor, just prior to measuring the inflammatory response, suggesting that the delay is due to stress-induced release of a factor that acutely masks the inhibition of the inflammatory response. This novel, unexpected feature of the effect of nonhabituating stress on inflammation may help explain variability in effects of stress in patients with inflammatory disease. The effect of nonhabituating stress on inflammation was dependent on the sympathoadrenal axis with no detectable contribution by the hypothalamic-pituitary-adrenal axis.

Phase I trial of lobradimil (RMP-7) and carboplatin in children with brain tumors

PURPOSE

To determine the maximum tolerated dose (MTD), the incidence and severity of toxicities, and the pharmacokinetics of lobradimil administered intravenously over 10 min in combination with carboplatin in children with refractory brain tumors.

METHODS

A group of 25 children with primary brain tumors received carboplatin and lobradimil on two consecutive days every 28 days. The 10-min lobradimil infusion began 5 min before the end of the carboplatin infusion. Four lobradimil dose levels (100, 300, 450 and 600 ng/kg ideal body weight, IBW) were studied in cohorts of 4 to 13 patients. Carboplatin was adaptively dosed based on the glomerular filtration rate to achieve a target plasma area under the concentration-time curve (AUC) of 7.0 mg min/ml per course (5.0 mg min/ml for patients who had previously received craniospinal radiation or myeloablative chemotherapy).

RESULTS

Lobradimil toxicity was immediate, tolerable and rapidly reversible. The most frequent toxicities were hypotension, flushing, headache and gastrointestinal complaints. One patient on the 600 ng/kg dose level had a seizure during the lobradimil infusion. The incidence and severity of lobradimil toxicities were not dose-related and the lobradimil dose was not escalated beyond the 600 ng/kg IBW dose level. Two patients had partial responses and ten patients had stable disease. Myelosuppression (thrombocytopenia more prominent than neutropenia) was the primary toxicity attributed to carboplatin. Lobradimil pharmacokinetics were characterized by rapid clearance from the plasma compartment and substantial interpatient variability.

CONCLUSIONS

The combination of carboplatin and lobradimil is safe and tolerable. An MTD for lobradimil was not defined because toxicity was not dose-related. The recommended pediatric phase II dose of lobradimil is 600 ng/kg IBW.

Cetirizine inhibits bradykinin-induced cutaneous wheal and flare in atopic and healthy subjects

BACKGROUND

Kinins are vasoactive mediators involved in allergic reactions. When applied on the skin or in the nose, bradykinin (BK) elicits inflammation that is poorly affected by previous H1-blockade. The aim of this study was to compare the possible effect of cetirizine (an H1-antagonist) on wheal and flare responses to BK, histamine, and compound 48/80 in atopic and healthy subjects.

METHODS

In a randomized, double-blind, crossover study, eight atopic and eight healthy subjects received cetirizine (10 mg/day) or placebo for 3 days before cutaneous tests. Intradermal tests (IDT) and prick tests (PT) were performed with BK (20 nmol/ml for IDT and 20 micromol/ml for PT), histamine (100 microg/ml IDT and 100 mg/ml PT), and compound 48/80 (100 microg/ml IDT and 100 mg/ml PT) as positive controls and saline as negative control. The skin responses were monitored by measurement of wheal and flare areas.

RESULTS

BK, histamine, and 48/80 induced wheal and flare reactions in all placebo-treated subjects. Histamine elicited larger wheal and flare reactions than BK and 48/80. IDT with BK induced four- to six-fold larger wheal and flare reaction than PT. No differences in BK-induced wheal and flare were observed between atopic and healthy subjects. In atopic subjects, cetirizine induced a significant reduction of flare reactions after the BK test (80% for IDT, and 94% for PT [P<0.01]). Moreover, cetirizine reduced significantly BK-induced wheals by 70% for IDT (P<0.01) and 65% for PT (P<0.01). A similar inhibiting effect of cetirizine was also observed in healthy subjects.

CONCLUSIONS

These findings showed that the wheal and flare reactions induced by BK challenge were markedly inhibited by previous intake of cetirizine. The mechanism by which this effect is mediated cannot be established at present.

Cetirizine inhibits bradykinin-induced cutaneous wheal and flare in atopic and healthy subjects

BACKGROUND

Kinins are vasoactive mediators involved in allergic reactions. When applied on the skin or in the nose, bradykinin (BK) elicits inflammation that is poorly affected by previous H1-blockade. The aim of this study was to compare the possible effect of cetirizine (an H1-antagonist) on wheal and flare responses to BK, histamine, and compound 48/80 in atopic and healthy subjects.

METHODS

In a randomized, double-blind, crossover study, eight atopic and eight healthy subjects received cetirizine (10 mg/day) or placebo for 3 days before cutaneous tests. Intradermal tests (IDT) and prick tests (PT) were performed with BK (20 nmol/ml for IDT and 20 micromol/ml for PT), histamine (100 microg/ml IDT and 100 mg/ml PT), and compound 48/80 (100 microg/ml IDT and 100 mg/ml PT) as positive controls and saline as negative control. The skin responses were monitored by measurement of wheal and flare areas.

RESULTS

BK, histamine, and 48/80 induced wheal and flare reactions in all placebo-treated subjects. Histamine elicited larger wheal and flare reactions than BK and 48/80. IDT with BK induced four- to sixfold larger wheal and flare reaction than PT. No differences in BK-induced wheal and flare were observed between atopic and healthy subjects. In atopic subjects, cetirizine induced a significant reduction of flare reactions after the BK test (80% for IDT, and 94% for PT [P < 0.01]). Moreover, cetirizine reduced significantly BK-induced wheals by 70% for IDT (P < 0.01) and 65% for PT (P < 0.01). A similar inhibiting effect of cetirizine was also observed in healthy subjects.

CONCLUSIONS

These findings showed that the wheal and flare reactions induced by BK challenge were markedly inhibited by previous intake of cetirizine. The mechanism by which this effect is mediated cannot be established at present.

A novel stable inhibitor of endopeptidases EC 3.4.24.15 and 3.4.24.16 potentiates bradykinin-induced hypotension

We have developed a novel inhibitor of the metalloendopeptidases EC 3.4.24.15 (EP24.15) and EC 3.4.24.16 (EP24.16), N-[1-(R, S)-carboxy-3-phenylpropyl]-Ala-Aib-Tyr-p-aminobenzoate (JA2), in which alpha-aminoisobutyric acid (Aib) is substituted for an alanine in a well-described but unstable inhibitor, cFP-AAY-pAB. This substitution increases the resistance of the inhibitor to degradation without altering potency. In the present study, we investigated the effects of JA2 (5 mg/kg) on the responses of mean arterial pressure to bradykinin, angiotensin I, and angiotensin II in conscious rabbits. The depressor responses to both low (10 ng/kg) and high (100 ng/kg) doses of bradykinin were increased 7.0+/-2. 7-fold and 1.5+/-0.3-fold, respectively, during the 30 minutes after JA2 administration (mean+/-SEM, n=8). Bradykinin potentiation was undiminished 4 hours after JA2 injection. In contrast, the hypertensive effects of angiotensins I and II were unaltered, indicating that the bradykinin-potentiating effects were not due to angiotensin-converting enzyme inhibition. These data suggest that JA2 is not only a potent and specific inhibitor of EP24.15 and EP24. 16 but is also stable in vivo. Furthermore, the potentiation of bradykinin-induced hypotension by JA2 suggests for the first time a role for one or both of these peptidases in the metabolism of bradykinin in the circulation.

Phase II studies of RMP-7 and carboplatin in the treatment of recurrent high grade glioma. RMP-7 European Study Group

The selective bradykinin analogue, RMP-7, transiently increases the permeability of the blood brain barrier and the delivery of hydrophilic agents into brain tumours. In 87 recurrent glioma patients (WHO Grade III/IV, median age 46, Karnofsky 70%) clinical and Magnetic Resonance Imaging (MRI) responses to i.v. cycles (q 28 days) of RMP-7 (300 ng/kg given as a 10 min infusion) and carboplatin (AUC 4-9) were assessed. 45 of these patients were chemotherapy naive (CN-RMP) and 42 had received one prior course of chemotherapy (CP-RMP). Neurological impairment, performance status and steroid use were measured prior to dosing at each cycle and tumour volume by 3-D MRI at the end of cycles 2, 4, 6, 9 and 12. Clinical evaluation of response demonstrated that 61% of CN-RMP patients were either stable or improved whilst this was 39% for CP-RMP patients, of which 37% and 8% improved respectively. Radiological evaluation showed 79% of CN-RMP patients were either stable, partial or complete responses and 24% for CP-RMP patients, of which 32% and 5% were CR or PR respectively. The median duration of response was 30.3 weeks in CN-RMP patients and 19.6 weeks in the CP-RMP group. Lack of response was associated with substantial baseline tumour volume. Drug toxicity was as previously reported for carboplatin. 11 patients had treatment-associated transient focal seizures. These results indicate that RMP-7 and carboplatin have significant activity in recurrent malignant glioma following radiotherapy.

Oral antinociception and oedema inhibition produced by NPC 18884, a non-peptidic bradykinin B2 receptor antagonist

This study investigates the antinociceptive and the oedema inhibition properties of the novel non-peptide bradykinin (BK) B2 receptor antagonist, NPC 18884. Given by i.p. or p.o. routes NPC 18884 produced graded and long-lasting (at least 2.5h and 5.0h, respectively, for i.p. and p.o. administration) inhibition of acetic acid-induced abdominal constrictions in mice, with mean ID50 values of 8.3 nmol/kg and 439.9 nmol/kg. NPC 18884 also inhibited kaolin-induced abdominal constrictions (44+/-9% and 48+/-3% of inhibition, for i.p. and p.o. routes, respectively). Given by i.p. or p.o. routes NPC 18884 attenuated both phases of formalin-induced licking, as well as formalin-induced oedema formation. At similar doses NPC 18884 produced significant inhibition of capsaicin-induced nociception. NPC 18884, like HOE 140 given i.p., prevented the nociception caused by BK with mean ID50 values of 0.85 nmol/kg and 0.44 nmol/kg, respectively. Given orally NPC 18884, but not HOE 140, caused graded inhibition of BK-induced nociception (mean ID50 value of 50 nmol/kg). In rats, NPC 18884 given i.p. prevented BK and carrageenan-induced hyperalgesia (mean ID50 values of 6 nmol/kg and 13 nmol/kg), without affecting the hyperalgesia induced by des-Arg9-bradykinin (DABK) or by prostaglandin E2 (PGE2). NPC 18884 given i.p. inhibited the mouse paw oedema induced by tyrosine8-bradykinin or by carrageenan, but had no effect on DABK-induced oedema in mice pre-treated with Escherichia coli endotoxin, or that induced by PGE2. Thus, the novel non-peptide BK B2 receptor antagonist NPC 18884 produces rapid onset, potent and relatively long-lasting oral antinociceptive and oedema inhibition properties. The anti-BK actions of NPC 18884 are quite selective towards the BK B2 receptor-mediated responses.

Endothelial function in Marfan syndrome: selective impairment of flow-mediated vasodilation

BACKGROUND

The cardiovascular complications of Marfan syndrome arise due to alterations in the structural and functional properties of fibrillin, a constituent of vascular connective tissues. Fibrillin-containing microfibrils are closely associated with arterial endothelial cells, indicating a possible functional role for fibrillin in the endothelium. Plasma concentrations of endothelial cell products are elevated in Marfan subjects, which indirectly indicates endothelial dysfunction. This study directly assessed flow- and agonist-mediated endothelium-dependent brachial artery reactivity in Marfan subjects.

METHODS AND RESULTS

In 20 Marfan and 20 control subjects, brachial artery diameter, blood flow, and blood pressure were measured by ultrasonic wall tracking, Doppler ultrasound, and photoplethysmography, respectively. Measurements were taken during hand hyperemia (a stimulus for endothelium-derived nitric oxide [NO] release in the upstream brachial artery) and after sublingual administration of the endothelium-independent vasodilator nitroglycerin. In 9 Marfan and 6 control subjects, the above parameters were also assessed during intra-arterial infusions of acetylcholine and bradykinin (agonists that stimulate NO production) and NG-monomethyl-L-arginine (L-NMMA, an inhibitor of NO production). Flow-mediated responses differed markedly between Marfan and control subjects (-1.6+/-3.5% versus 6. 50+/-4.1%, respectively; P<0.0001), whereas nitroglycerin produced similar vasodilation (14.2+/-5.7% versus 15.2+/-7.8%; P=NS). Agonist-induced vasodilation to incremental intra-arterial infusions of acetylcholine and bradykinin were not significantly different between Marfan and control subjects, and intra-arterial L-NMMA produced similar reductions in brachial artery diameter in both groups.

CONCLUSIONS

These data demonstrate impaired flow-mediated but preserved agonist-mediated endothelium-dependent vasodilation in Marfan subjects and suggest preservation of basal NO release. Selective loss of flow-mediated dilation suggests a role for fibrillin in endothelial cell mechanotransduction.

Effects of the orally active non-peptide bradykinin B2 receptor antagonist, FR173657, on plasma extravasation in guinea pig airways

We investigated the effect of the orally active non-peptide bradykinin B2 receptor antagonist, FR173657 (E)-3-(6-acetamido-3-pyridyl)-N-[N-[2.4-di-chloro-3-[(2-methyl-8-quinoli nyl)oxymethyl]phenyl]-N-methy-laminocarbonylmethyl] acrylamide), on plasma extravasation mediated by activation of sensory nerves in guinea pig airways. Plasma extravasation was assessed by the photometric measurement of the extravasated Evans blue after formamide extraction. We found that the increase in Evans blue dye extravasation evoked by an aerosol of bradykinin (0.1 mM, 2 min) in the presence of phosphoramidon (2.5 mg/kg, i.v.) was abolished completely by FR173657 (20 mg/kg, p.o.) in the trachea and main bronchi. In sensitized guinea pigs pretreated with phosphoramidon, FR173657 (20 mg/kg, p.o.) inhibited plasma extravasation evoked by ovalbumin aerosol (5%, 2 min) by 77+/-14.2% in the trachea and 65+/-11.2% in the main bronchi. FR173657 (20 mg/kg, p.o.) did not affect the plasma extravasation caused by aerosolised capsaicin. These findings suggest that FR173657 is an orally active, promising anti-inflammatory agent for kinin-dependent inflammation following antigen challenge.

Intra-arterial Cereport (RMP-7) and carboplatin: a dose escalation study for recurrent malignant gliomas

OBJECTIVE

Animal and human studies have shown increased delivery of radiolabeled compounds across the blood-brain-tumor barrier using intra-arterial (IA) Cereport (RMP-7; Alkermes Inc., Cambridge, MA) with a radiolabeled tracer. This present study assesses the safety, tolerance, and preliminary efficacy of the IA administration of carboplatin with Cereport.

METHODS

An open-label dose escalation study of IA Cereport (10-300 ng/kg) with 100 mg of IA carboplatin was conducted in 11 patients with recurrent malignant gliomas and 1 patient treated adjuvantly after radiation therapy. Tumor size and laboratory and clinical statuses were assessed.

RESULTS

Adverse events were mainly neurological in nature and corresponded to the anatomic location of the tumor. Karnofsky performance scale scores did not decline, overall, for those patients who had tumor response. Tumor shrinkage was observed in three of six evaluable patients who received a dose of 300 ng/kg with durable responses of 60, 64, and 106+ weeks.

CONCLUSION

Previous studies have demonstrated increased permeability in human gliomas using IA Cereport. This study demonstrates durable imaging responses using 100 mg of IA carboplatin in combination with Cereport. The drug combination in this patient population seems to be safe and acceptable, providing a novel means of antitumor dose intensification.

Role of non-nitric oxide non-prostaglandin endothelium-derived relaxing factor(s) in bradykinin vasodilation

The most conspicuous effect of bradykinin following its administration into the systemic circulation is a transient hypotension due to vasodilation. In the present study most of the available evidence regarding the mechanisms involved in bradykinin-induced arterial vasodilation is reviewed. It has become firmly established that in most species vasodilation in response to bradykinin is mediated by the release of endothelial relaxing factors following the activation of B2-receptors. Although in some cases the action of bradykinin is entirely mediated by the endothelial release of nitric oxide (NO) and/or prostacyclin (PGI2), a large amount of evidence has been accumulated during the last 10 years indicating that a non-NO/PGI2 factor accounts for bradykinin-induced vasodilation in a wide variety of perfused vascular beds and isolated small arteries from several species including humans. Since the effect of the non-NO/PGI2 endothelium-derived relaxing factor is practically abolished by disrupting the K+ electrochemical gradient together with the fact that bradykinin causes endothelium-dependent hyperpolarization of vascular smooth muscle cells, the action of such factor has been attributed to the opening of K+ channels in these cells. The pharmacological characteristics of these channels are not uniform among the different blood vessels in which they have been examined. Although there is some evidence indicating a role for KCa or KV channels, our findings in the mesenteric bed together with other reports indicate that the K+ channels involved do not correspond exactly to any of those already described. In addition, the chemical identity of such hyperpolarizing factor is still a matter of controversy. The postulated main contenders are epoxyeicosatrienoic acids or endocannabinoid agonists for the CB1-receptors. Based on the available reports and on data from our laboratory in the rat mesenteric bed, we conclude that the NO/PGI2-independent endothelium-dependent vasodilation induced by BK is unlikely to involve a cytochrome P450 arachidonic acid metabolite or an endocannabinoid agonist.

Central involvement of kinin B1 and B2 receptors in the febrile response induced by endotoxin in rats

1. The effect of central injection of selective kinin B1 and B2 receptor antagonists on the febrile response induced by endotoxin (E. coli lipopolysaccharide, LPS) in rats was investigated. 2. Intracerebroventricular (i.c.v.) injection of a selective B2 receptor antagonist (Hoe-140, 8 nmol) reduced the early (0-2 h), but increased the late phase (4-6 h) of the febrile response induced by intravenous (i.v.) injection of LPS (0.5 microgram kg-1). 3. Co-administration of Hoe-140 (8 nmol, i.c.v.) with LPS (0.5 microgram kg-1, i.v.), followed 2.5 h later by the i.c.v. injection of a selective B1 receptor antagonist [des-Arg9-Leu8]-bradykinin (BK, 8 nmol), significantly reduced the febrile response induced by LPS throughout the whole experimental period. 4. Intravenous injection of Hoe-140 (1 mg kg-1) significantly reduced the febrile response induced by LPS (0.5 microgram kg-1, i.p.). 5. Pretreatment (24 h) with LPS (0.5 microgram kg-1, i.v.) reduced the febrile response induced by BK or [Tyr8]-BK (both, 5 nmol, i.c.v.), but markedly increased the febrile response induced by [des-Arg9]-BK (5 nmol, i.c.v.). The response induced by [des-Arg9]-BK in LPS-pretreated rats was significantly inhibited by co-injection of [des-Arg9-Leu8]-BK (15 nmol, i.c.v.). 6. The results suggest that kinins are involved in the induction of LPS-induced fever and that central B2 and B1 receptors are activated during the initial and late phase of this response, respectively. The results also suggest that downregulation and/or desensitization of B2 receptors and induction and/or upregulation of B1 receptors in LPS-pretreated animals may have a significant pathophysiological role in the induction and maintenance of fever. These observations may be specifically important in the case of chronic inflammatory conditions, because the BK metabolite [des-Arg9]-BK, so far considered an inactive metabolite, acquires an active and relevant role with the progressive expression of B1 receptors that occurs in such states.