Marco Cicardi

Plasma bradykinin in angio-oedema

BACKGROUND Bradykinin is believed to be the main mediator of symptoms in hereditary (HA) and acquired (AA) angio-oedema due to C1 esterase inhibitor deficiency, as well as in angio-oedema that complicates treatment with inhibitors of angiotensin-converting enzyme (ACE). Difficulties in the measurement of kinin concentrations, however, have so far precluded the demonstration of an incontrovertible change in plasma bradykinin concentrations in these disorders. By developing a reliable assay we have been able to follow bradykinin concentrations during attacks and during remission in HA and in AA, and also in a patient treated with an ACE-inhibitor. METHODS Liquid-phase extraction, high-performance liquid chromatography, and RIA were used for specific measurement of plasma bradykinin concentrations in 22 patients with HA and in 22 healthy volunteers of similar age and sex distribution. Four patients with AA and one hypertensive patient treated with the ACE inhibitor captopril were also studied. FINDINGS Among the healthy volunteers plasma bradykinin concentration was inversely proportional to age. The geometric mean plasma bradykinin concentration in the healthy volunteers was 2.2 fmol/mL (SD 2.2), compared with 3.9 fmol/mL (3.7) among patients with HA during remission (p=0.095). Bradykinin was also high in the patients with AA (10.4 fmol/mL [1.6]). During acute attacks of oedema, in both HA and AA, plasma bradykinin rose to two to 12 times the upper limit of normal. Infusion of C1-esterase inhibitor (the deficient factor in both HA and AA) immediately lowered bradykinin concentrations. In the patient receiving the ACE-inhibitor captopril, bradykinin concentration was very high at 47 fmol/mL during an acute attack of angio-oedema, but normal at 3.2 fmol/mL in remission after withdrawal of the drug. INTERPRETATION A sensitive method for measurement of plasma bradykinin provided the means to show that concentrations of this peptide decrease with age in healthy people. Although the differences between patients in remission and healthy controls did not reach statistical significance, there were substantial rises in bradykinin during acute attacks of hereditary, acquired, or captopril-induced angio-oedema.

Hereditary and acquired C1-inhibitor deficiency: biological and clinical characteristics in 235 patients.

Two hundred and twenty-six patients with inherited C1 inhibitor (C1-INH) deficiency, also known as hereditary angioedema (HAE), have been studied. They belonged to 80 unrelated families, and in 11 of them C1-INH was functionally deficient but antigenically normal (type II HAE). Genetic analysis of type 1 families demonstrated restriction fragment length polymorphisms in 11% and abnormal mRNAs in 25%. In type II families, the site of the mutation appeared to determine the rate of catabolism of the dysfunctional C1-INH and its antigenic plasma levels. Clinical symptoms (subcutaneous and mucous swellings) generally first appeared within the second decade of life. The frequency of symptoms was highly variable from patient to patient, but a few patients remained asymptomatic throughout their lives. Prophylactic treatment with attenuated androgens was administered to 59 patients and was totally effective in 57, without significant side effects. Sixty-seven laryngeal and 15 abdominal attacks were treated with C1-INH plasma concentrate, yielding initial regression of symptoms in 30 to 90 minutes. The acquired deficiency of C1-INH, also known as acquired angioedema, was diagnosed in 9 patients. Eight of them had an autoantibody against C1-INH; the only patient without the autoantibody had associated chronic lymphocytic leukemia. Prophylactic treatment with attenuated androgens was effective in this last patient, while those with the autoantibody against C1-INH benefited from prophylaxis with antifibrinolytic agents. Replacement therapy with C1-INH concentrate was necessary only for patients with autoantibodies and required doses 3 or 4 times higher than those used in HAE.

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.)

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

To cite this article: Cicardi M, Bork K, Caballero T, Craig T, Li HH, Longhurst H, Reshef A, Zuraw B on behalf of HAWK (Hereditary Angioedema International Working Group). Evidence‐based recommendations for the therapeutic management of angioedema owing to hereditary C1 inhibitor deficiency: consensus report of an International Working Group. Allergy 2012; 67: 147–157.

Classification, diagnosis, and approach to treatment for angioedema: consensus report from the Hereditary Angioedema International Working Group

Angioedema is defined as localized and self‐limiting edema of the subcutaneous and submucosal tissue, due to a temporary increase in vascular permeability caused by the release of vasoactive mediator(s). When angioedema recurs without significant wheals, the patient should be diagnosed to have angioedema as a distinct disease. In the absence of accepted classification, different types of angioedema are not uniquely identified. For this reason, the European Academy of Allergy and Clinical Immunology gave its patronage to a consensus conference aimed at classifying angioedema. Four types of acquired and three types of hereditary angioedema were identified as separate forms from the analysis of the literature and were presented in detail at the meeting. Here, we summarize the analysis of the data and the resulting classification of angioedema.

Ecallantide for the Treatment of Acute Attacks in Hereditary Angioedema

BACKGROUND Hereditary angioedema is a rare genetic disorder characterized by acute, intermittent, and potentially life-threatening attacks of edema of the skin and mucosa. We evaluated ecallantide, a newly developed recombinant plasma kallikrein inhibitor, for the treatment of acute attacks of angioedema. METHODS In this double-blind, placebo-controlled trial, patients with hereditary angioedema presenting with an acute attack were randomly assigned, in a 1:1 ratio, to receive subcutaneous ecallantide, at a dose of 30 mg, or placebo. Two measures of patient-reported outcomes were used to assess the response: treatment outcome scores, which range from +100 (designated in the protocol as significant improvement in symptoms) to -100 (significant worsening of symptoms), and the change from baseline in the mean symptom complex severity score, which range from +2 (representing a change from mild symptoms at baseline to severe symptoms after) to -3 (representing a change from severe symptoms at baseline to no symptoms after). The primary end point was the treatment outcome score 4 hours after study-drug administration. Secondary end points included the change from baseline in the mean symptom complex severity score at 4 hours and the time to significant improvement. RESULTS A total of 71 of the 72 patients completed the trial. The median treatment outcome score at 4 hours was 50.0 in the ecallantide group and 0.0 in the placebo group (interquartile range [IQR], 0.0 to 100.0 in both groups; P=0.004). The median change in the mean symptom complex severity score at 4 hours was -1.00 (IQR, -1.50 to 0.00) with ecallantide, versus -0.50 (IQR, -1.00 to 0.00) with placebo (P=0.01). The estimated time to significant improvement was 165 minutes with ecallantide versus more than 240 minutes with placebo (P=0.14). There were no deaths, treatment-related serious adverse events, or withdrawals owing to adverse events. CONCLUSIONS Four hours after administration of ecallantide or placebo for acute attacks of angioedema in patients with hereditary angioedema, patient-reported treatment outcome scores and mean symptom complex severity scores were significantly better with ecallantide than with placebo. (Funded by Dyax; ClinicalTrials.gov number, NCT00262080.)

Bradykinin-Mediated Angioedema

To the Editor: Angioedema is a nonitchy, pale swelling of subcutaneous or submucosal tissue that tends to recur chronically and can become life-threatening if the swelling occurs in the upper airwa...

Hereditary angio-oedema

Hereditary angio-oedema is caused by a heterozygous deficiency of C1 inhibitor. This inhibitor regulates several inflammatory pathways, and patients with hereditary angio-oedema have intermittent cutaneous or mucosal swellings because of a failure to control local production of bradykinin. Swellings typically evolve in several hours and persist for a few days. In addition to orofacial angio-oedema, painless swellings affect peripheries, which causes disfigurement or interference with work and other activities of daily living. Angio-oedema affecting the gastrointestinal tract or abdominal viscera causes severe pain often with vomiting due to oedematous bowel obstruction. About 2% of swellings involve the larynx and can be fatal if untreated. About 50% of patients have laryngeal swellings that are potentially fatal despite prophylaxis. In this Seminar we review the clinical features, diagnosis, and management of hereditary angio-oedema, with specific emphasis on the new treatments available for acute swellings.

Bradykinin and the pathophysiology of angioedema

Angioedema has different causes and different clinical presentations. Some types of angioedema may be mediated by bradykinin. We measured plasma levels of bradykinin-(1-9)nonapeptide by radioimmunoassay after high-performance liquid chromatography in patients with different types of angioedema during acute attacks and/or in remission, i.e. hereditary C1-inhibitor deficiency, angiotensin converting enzyme (ACE) inhibitor treatment, idiopathic non histaminergic and responders to antihistamines. Eleven patients with the deficiency of C1-inhibitor had very high levels of bradykinin during acute attacks of angioedema (18.0-90.0 pM) (normal range 0.2-7.1 pM). In three patients with history of ACE inhibitor-related angioedema, plasma bradykinin was high during ACE inhibitor treatment (62.0, 8.9 and 27.0 pM) and in a fourth patient was 47.0 pM during an acute attack and decreased by 93% to 3.2 pM after withdrawal of the ACE inhibitor. The patient with idiopathic angioedema, during an acute attack involving the right arm, had high levels of bradykinin in the venous blood refluent from the angioedematous arm (20.0 pM) while in the contralateral arm bradykinin levels were normal (6.6 pM), similarly to what we previously observed in cases of brachial angioedema due to C1-inhibitor deficiency. The four patients with angioedema responsive to antihistamines had normal levels of bradykinin even during acute attacks (5.7, 3.4, 4.7 and 1.2 pM). In one of these patients who had a brachial angioedema, bradykinin levels were normal in the venous blood refluent from both arms. Bradykinin is involved in hereditary C1-inhibitor deficiency angioedema, in ACE inhibitor-related angioedema, and in idiopathic non-histaminergic angioedema, while bradykinin is not related to allergen-dependent or idiopathic angioedema that are responsive to antihistamines.

C1-inhibitor deficiency and angioedema: molecular mechanisms and clinical progress

C1 inhibitor (C1-INH, also known as SERPING1) can be deficient in plasma as a result of genetic or acquired conditions, and this causes an episodic, local increase in vascular permeability in the subcutaneous and submucosal layers, identified as angioedema (hereditary or acquired). Bradykinin, the mediator of the increase in vascular permeability, is released on inappropriate activation of the contact system, which is controlled by C1 inhibitor. Therapy aims to reverse or prevent angioedema. Advances in understanding the complex effects of C1-INH deficiency at the molecular level have led to new molecular-targeted approaches. Three new treatments, an inhibitor of kallikrein to prevent bradykinin release, an antagonist of the bradykinin receptor to prevent its action and a recombinant human C1-INH produced in transgenic animals, are under clinical evaluation currently. Here, we review the molecular mechanisms underlying angioedema due to C1-inhibitor deficiency and clinical progress using molecular-targeted interventions.