Biochemical basis of angioedema associated with recombinant tissue plasminogen activator treatment: an in vitro experimental approach

Risk of angioedema and thrombolytic therapy among stroke patients: An analysis of data from the FDA Adverse Event Reporting System database

The angioedema risk may vary among stroke patients receiving different thrombolytic agents. This study aimed to investigate the angioedema risk associated with different thrombolytic agents and to identify associated risk factors. We conducted a large-scale retrospective pharmacovigilance study using the FDA Adverse Event Reporting System (FAERS) database. Stroke patients receiving thrombolytic therapy (i.e., alteplase or tenecteplase) were identified, and the associations with angioedema were explored using disproportionality analysis and time-to-onset analysis. Additionally, we used adapted Bradford Hill criteria to confirm these associations. Risk factors for angioedema were explored using stepwise logistic regression. A total of 17,776 stroke patients were included, with 2973 receiving alteplase and 278 receiving tenecteplase. Disproportionality analysis revealed that angioedema might be associated with alteplase (adjusted ROR [aROR] 5.13 [95 ​% CI, 4.55-5.79]) or tenecteplase (aROR 2.72 [95 ​% CI, 1.98-3.67]). The adapted Bradford Hill criteria suggested a probable causal relationship between alteplase and angioedema, whereas there was insufficient evidence of a probable causal relationship with tenecteplase. Multivariate analysis revealed that ACE-inhibitors use (aROR 9.73 [95 ​% CI, 7.29-12.98]), female sex (aROR 1.38 [95 ​% CI, 1.13-1.67]) and hypertension (aROR 2.11 [95 ​% CI, 1.52-2.92]) were significant risk factors for angioedema among alteplase-treated stroke patients. Our study suggested that alteplase is associated with a greater risk of angioedema among stroke patients, but there is insufficient evidence to support an association between tenecteplase and angioedema. Clinicians should be vigilant for this potentially life-threatening complication, particularly in patients with identified risk factors. It is also prudent to consider tenecteplase as an alternative, if available.

Tenecteplase-associated orolingual angioedema: A case report and literature review

PURPOSE

Orolingual angioedema (OA) secondary to administration of thrombolytic therapy is a rare, but serious, known adverse effect. Despite the lack of robust evidence for their use, C1 esterase inhibitors are recommended by guidelines for the treatment of refractory thrombolytic-associated OA. This report highlights the use of a C1 esterase inhibitor in a patient with tenecteplase-associated OA unresolved by antihistamine and corticosteroid therapy.

SUMMARY

A 67-year-old white male with a history of hypertension managed with lisinopril presented to the emergency department with acute onset of slurred speech and left-sided hemiparesis. Following workup, an outside hospital's neurology stroke team suspected an acute infarct and determined the patient to be a candidate for tenecteplase. Approximately 1 hour after tenecteplase administration, the patient began complaining of dyspnea and mild oral angioedema. Immediate interventions for OA management included intravenous therapy with dexamethasone 10 mg, diphenhydramine 25 mg, and famotidine 20 mg. After an additional 30 minutes, the patient's OA symptoms continued to progress and a C1 esterase inhibitor (Berinert) was administered. Shortly after administration of the C1 esterase inhibitor, the patient's symptoms continued to worsen, ultimately leading to endotracheal intubation. Following intubation, symptom improvement was noted, and the patient was safely extubated after 30 hours.

CONCLUSION

Although rare, OA is a potentially life-threatening complication of tenecteplase therapy and requires prompt pharmacological intervention to optimize patient outcomes. Currently, no single agent or treatment algorithm exists that has shown significant efficacy or safety in the setting of thrombolytic-associated OA. Until data are available for C1 esterase inhibitors in this application, these inhibitors should only be considered if there is continued symptom progression after intravenous administration of corticosteroids and antihistamines.

Ipsilateral orolingual angioedema following rhTNK-tPA administration for acute ischemic stroke

Recombinant human tenecteplase tissue-type plasminogen activator (rhTNK-tPA), a genetically modified variant of conventional alteplase with longer half-life and higher fibrin specificity, has now emerged as a reasonable choice for thrombolytic treatment of acute ischemic stroke (AIS) in China. Orolingual angioedema is a rare but potentially life-threatening complication of intravenous thrombolysis. Currently, there is no documented evidence of orolingual angioedema occurring after thrombolysis with rhTNK-tPA. In this report, we present a unique case of a 75-year-old Chinese man who developed ipsilateral orolingual angioedema following the administration of rhTNK-tPA for AIS. Our case emphasizes the need for caution when using rhTNK-tPA due to its potential to induce ipsilateral orolingual angioedema.

A mechanism for hereditary angioedema caused by a methionine-379-to-lysine substitution in kininogens

ABSTRACT

Hereditary angioedema (HAE) is associated with episodic kinin-induced swelling of the skin and mucosal membranes. Most patients with HAE have low plasma C1-inhibitor activity, leading to increased generation of the protease plasma kallikrein (PKa) and excessive release of the nanopeptide bradykinin from high-molecular-weight kininogen (HK). However, disease-causing mutations in at least 10% of patients with HAE appear to involve genes for proteins other than C1-inhibitor. A point mutation in the Kng1 gene encoding HK and low-molecular weight kininogen (LK) was identified recently in a family with HAE. The mutation changes a methionine (Met379) to lysine (Lys379) in both proteins. Met379 is adjacent to the Lys380-Arg381 cleavage site at the N-terminus of the bradykinin peptide. Recombinant wild-type (Met379) and variant (Lys379) versions of HK and LK were expressed in HEK293 cells. PKa-catalyzed kinin release from HK and LK was not affected by the Lys379 substitutions. However, kinin release from HK-Lys379 and LK-Lys379 catalyzed by the fibrinolytic protease plasmin was substantially greater than from wild-type HK-Met379 and LK-Met379. Increased kinin release was evident when fibrinolysis was induced in plasma containing HK-Lys379 or LK-Lys379 compared with plasma containing wild-type HK or LK. Mass spectrometry revealed that the kinin released from wild-type and variant kininogens by PKa is bradykinin. Plasmin also released bradykinin from wild-type kininogens but cleaved HK-Lys379 and LK-Lys379 after Lys379 rather than Lys380, releasing the decapeptide Lys-bradykinin (kallidin). The Met379Lys substitutions make HK and LK better plasmin substrates, reinforcing the relationship between fibrinolysis and kinin generation.

Angiotensin-Converting Enzyme Inhibitors and Other Medications Associated With Angioedema

Angioedema is a localized swelling of the dermis, subcutaneous tissues, and/or submucosal tissues caused by fluid extravasation into these tissues. Angioedema is associated with certain vasoactive molecules and is typically mediated by histamine or bradykinin. It manifests clinically as facial edema, swelling of the extremities and urogenital area, and potential involvement of the larynx, leading to dyspnea and inspiratory stridor, which can become life-threatening. Histamine-mediated angioedema is associated with urticaria and pruritus and will show classic signs of allergic (type 1 hypersensitivity) reactions. Bradykinin-mediated angioedema is often familial (hereditary angioedema) and is more often associated with gastrointestinal symptoms (abdominal pain, nausea, vomiting, diarrhea), edema of the extremities and trunk, and a lack of urticaria and pruritus. Angiotensin-converting enzyme inhibitors (ACEIs) are a class of medications commonly prescribed for hypertension, heart failure, and diabetic nephropathy. ACEIs are associated with an increased risk of angioedema, which can range from a mild reaction to severe and life-threatening. ACEI-induced angioedema is a bradykinin-mediated reaction that can occur in individuals with a genetic predisposition. Other medications, such as angiotensin receptor blockers, nonsteroidal anti-inflammatory drugs, and certain antibiotics, most notably those in the beta-lactam class, can also cause drug-induced angioedema. The present investigation describes current knowledge of the pathophysiology, epidemiology, clinical manifestations, predisposing factors, and management of drug-induced angioedema.

The Renin-Angiotensin System in COVID-19: Can Long COVID Be Predicted?

(1) Background: Co-morbidities such as hypertension and cardiovascular disease are major risk factors for severe COVID-19. The renin-angiotensin system (RAS) is critically involved in their pathophysiology and is counter-balanced by both angiotensin-converting enzyme 2 (ACE2), the functional receptor of SARS-CoV-2, and the kallikrein-kinin system (KKS). Considerable research interest with respect to COVID-19 treatment is currently being directed towards the components of these systems. In earlier studies, we noticed significantly reduced carboxypeptidase N (CPN, KKS member) activity and excessive angiotensin-converting enzyme (ACE, RAS member) activity in the sera of both hospitalized COVID-19 patients and a subgroup of convalescent patients. The data had been obtained using labeled bradykinin (BK) as a reporter peptide, which is a target of both CPN and ACE. The data were supplemented with mass-spectrometry-based serum proteomic analysis. Here, we hypothesize that the degree of BK serum degradation could be indicative of Long COVID. (2) Review and Discussion: The recent literature is briefly reviewed. The fact that the levels of the BK serum degradation products did not reach normal concentrations in almost half of the patients during convalescences could have been partially due to a dysregulated RAS. (3) Conclusions: Standard tests for routine patient care in Long COVID come often back normal. We suggest that the measurement of selected members of the RAS such as ACE and angiotensin II or the use of our BK degradation assay could identify Long COVID candidates. Clinical studies are required to test this hypothesis.

Retropharyngeal hematoma mimicking angioedema after intravenous thrombolysis for acute ischemic stroke

Tissue plasminogen activator (tPA) is a cornerstone treatment for acute ischemic stroke (AIS). Administration of tPA is not without risk, and can provoke life threatening adverse reactions. Retropharyngeal hematoma (RPH) following tPA administration has only been reported after tenecteplase (TNK) administration for ST elevation myocardial infarction (STEMI). A 78 year old patient received tPA for AIS. Following administration of tPA, this patient developed acute signs and symptoms of what appeared to be a more well-known adverse reaction of tPA administration - angioedema. After CT and laboratory findings, our patient received cryoprecipitate for tPA reversal. Our case highlights a unique case of RPH mimicking angioedema following tPA administration.

High Angiotensin-Converting Enzyme and Low Carboxypeptidase N Serum Activity Correlate with Disease Severity in COVID-19 Patients

(1) Background: Angiotensin-converting enzyme 2 (ACE2) is a functional receptor of SARS-CoV-2 and counter-balances ACE in the renin–angiotensin system (RAS). An imbalance of the RAS could be associated with severe COVID-19 progression. (2) Methods: Activities of serum proteases angiotensin-converting enzyme (ACE) and carboxypeptidase N (CPN) for 45 hospitalized and 26 convalescent COVID-19 patients were investigated vs. healthy controls using labeled bradykinin (DBK) degradation with and without inhibition by captopril as a read-out. Data were correlated to clinical parameters. (3) Results: DBK degradation and CPN activity were significantly reduced gender-independently in COVID-19 and returned to normal during convalescence. ACE activity was over-active in severe disease progression; product DBK1-5 was significantly increased in critically ill patients and strongly correlated with clinical heart and liver parameters. ACE inhibitors seemed to be protective, as DBK1-5 levels were normal in moderately ill patients in contrast to critically ill patients. (4) Conclusions: CPN and ACE serum activity correlated with disease severity. The RAS is affected in COVID-19, and ACE could be a therapeutic target. Further proof from dedicated studies is needed.

Reduced serum protease activity in Complex Regional Pain Syndrome: The impact of angiotensin-converting enzyme and carboxypeptidases

Complex Regional Pain Syndrome (CRPS) occurs in about 2% of patients after fracture of the limbs. In an earlier clinical study with 102 probands we have shown that the serum protease network in CRPS might be less effective. Based on these results we hypothesized that angiotensin-converting enzyme (ACE) and carboxypeptidase N (CPN) activity contribute to the differences of labeled bradykinin (DBK) degradation by patients' sera. Details of the enzymatic processes remained however unclear. The contributions of ACE and CPN in the serum degradation of DBK were studied using specific inhibitors. CPN1-ELISA was performed in serum. It was confirmed that the majority of DBK was degraded by ACE and CPN. The data delivered proof that the ACE serum activity was lowered in CRPS. High-resolution mass spectrometry was additionally used for protein expression analysis of sera of above study cohort (CRPS vs. healthy probands). According to principal component analysis of these data, significant differences between CRPS and control samples only occurred in sera of females younger than 46 years. In these CRPS patients, a number of defence / immunity-related proteins and members of the renin-angiotensin system (RAS) protein network were regulated. The impact of CPN in CRPS pathophysiology is subject to further investigation. The data support the hypothesis that both the RAS and the innate immune system might be affected in CRPS. A database of regulated serum proteins was established for future research.

Isolated tongue angioedema after alteplase infusion in acute ischemic stroke

BACKGROUND

Angioedema, like anaphylaxis, has been reported as a rare adverse event of alteplase infusion in acute ischemic stroke.

OBJECTIVE

We report the case of a patient with acute ischemic stroke who after treatment of alteplase developed angioedema.

METHODS

We report the case of an 81-year-old woman who presented to our observation with acute ischemic stroke. The patient was on therapy with 100 mg acetylsalicylic acid and a triple combination antihypertensive drug (perindopril 10 mg + 2.5 mg indapamide + 5 mg amlodipine). The patient was treated with alteplase infusion.

RESULTS

Five minutes after the end of the alteplase infusion (0.9 mg/kg for 1 hour) the patient developed isolated angioedema of the lips and tongue.

CONCLUSION

Although the incidence of alteplase-induced angiodema in these patients is rare, this case report suggests the need for routine inspection of the tongue in acute ischemic patient in treatment with alteplase infusion, especially in female patients in treatment with ACE inhibitors.

In Vitro Modeling of Bradykinin-Mediated Angioedema States

Kinins (peptides related to bradykinin, BK) are formed from circulating substrates, the kininogens, by the action of two proteases, the kallikreins. The only clinical application of a BK receptor ligand, the B₂ receptor antagonist icatibant, is the treatment of the rare hereditary angioedema (HAE) caused by the deficiency of C1-esterase inhibitor (C1-INH). Less common forms of HAE (genetic variants of factor XII, plasminogen, kininogen) are presumably mediated by increased BK formation. Acquired forms of BK-mediated angioedema, such as that associated with angiotensin-I converting enzyme (ACE) inhibition, are also known. Antibody-based analytical techniques are briefly reviewed, and support that kinins are extremely short-lived, prominently cleared by ACE. Despite evidence of continuous activation of the kallikrein–kinin system in HAE, patients are not symptomatic most of the time and their blood or plasma obtained during remission does not generate excessive immunoreactive BK (iBK), suggesting effective homeostatic mechanisms. HAE-C1-INH and HAE-FXII plasmas are both hyperresponsive to fibrinolysis activation. On another hand, we suggested a role for the alternate tissue kallikrein–kinin system in patients with a plasminogen mutation. The role of the BK B₁ receptor is still uncertain in angioedema states. iBK profiles under in vitro stimulation provide fresh insight into the physiopathology of angioedema.

Measurement of Bradykinin Formation and Degradation in Blood Plasma: Relevance for Acquired Angioedema Associated With Angiotensin Converting Enzyme Inhibition and for Hereditary Angioedema Due to Factor XII or Plasminogen Gene Variants

Bradykinin (BK)-mediated angioedema (AE) states are rare acquired or hereditary conditions involving localized edema of the subcutaneous and submucosal tissues. Citrated plasma from healthy volunteers or patients with hereditary angioedema (HAE) with normal level of C1-inhibitor (C1-INH) was used to investigate pathways of BK formation and breakdown relevant to AE physiopathology. The half-life of BK (100 nM) added to normal plasma was 34 s, a value that was increased ~12-fold when the angiotensin converting enzyme (ACE) inhibitor enalaprilat (130 nM) was added (enzyme immunoassay measurements). The BK half-life was similarly increased ~5-fold following 2 daily oral doses of enalapril maleate in healthy volunteers, finding of possible relevance for the most common form of drug-associated AE. We also addressed the kinetics of immunoreactive BK (iBK) formation and decline, spontaneous or under three standardized stimuli: tissue kallikrein (KLK-1), the particulate material Kontact-APTT™ and tissue plasminogen activator (tPA). Relative to controls, iBK production was rapid (10–20 min) and very intense in response to tPA in plasma of female heterozygotes for variants in gene F12 coding for factor XII (FXII) (p.Thr328Lys, 9 patients; p.Thr328Arg, one). An increased response to Kontact-APTT™ and an early tPA-induced cleavage of anomalous FXII (immunoblots) were also observed. Biotechnological inhibitors showed that the early response to tPA was dependent on plasmin, FXIIa and plasma kallikrein. Results from post-menopausal and pre-menopausal women with HAE-FXII were indistinguishable. The iBK production profiles in seven patients with the plasminogen p.Lys330Glu variant (HAE-PLG) did not significantly differ from those of controls, except for an unexpected, rapid and lanadelumab-resistant potentiation of KLK-1 effect. This enzyme did not cleave plasminogen or factor XII, suggesting a possible idiosyncratic interaction of the plasminogen pathogenic variant with KLK-1 activity. KLK-1 abounds in salivary glands and human saliva, hypothetically correlating with the clinical presentation of HAE-PLG that includes the swelling of the tongue, lips and contiguous throat tissues. Samples from HAE patients with normal C1-INH levels and F12 gene did not produce excessive iBK in response to stimuli. The ex vivo approach provides physiopathological insight into AE states and supports the heterogeneous physiopathology of HAE with normal C1-INH.

Angioedema associated with thrombolysis for ischemic stroke: analysis of a case-control study

BACKGROUND

Bradykinin-mediated angioedema (AE) is a complication associated with thrombolysis for acute ischemic stroke. Risk factors are unknown and management is discussed.

OBJECTIVES

To clarify risk factors associated with bradykinin-mediated AE after thrombolysis for acute ischemic stroke.

METHODS

In a case-control study conducted at a French reference centre for bradykinin angiœdema, patients with thrombolysis for acute ischemic stroke and a diagnosis of bradykinin-mediated angiœdema, were compared to controls treated with thrombolysis treatment without angiœdema.

RESULTS

Fifty-three thrombolysis-related AE were matched to 106 control subjects. The sites of attacks following thrombolysis for ischemic stroke mainly included tongue (34/53, 64%) and lips (26/53, 49%). The upper airways were involved in 37 (70%) cases. Three patients required mechanical ventilation. Patients with bradykinin-mediated angiœdema were more frequently women [33 (62%) vs. 44 (42%); P = 0.01], had higher frequency of prior ischemic stroke [12 (23%) vs. 9 (8%); P = 0.01], hypertension [46 (87%) vs. 70 (66%); P = 0.005], were more frequently treated with angiotensin-converting enzyme inhibitor [37 (70%) vs. 28 (26%); P < 0.001] and were more frequently hospitalized in intensive care medicine [ICU; 11 (21%) vs. 5 (5%); P = 0.004]. In multivariate analysis, factors associated with thrombolysis-related AE were female sex [odds ratio (OR), 3.04; 95% confident interval (CI), 1.32-7.01; P = 0.009] and treatment with angiotensin-converting enzyme inhibitors [(OR), 6.08; 95% (CI), 2.17-17.07; P < 0.001].

CONCLUSIONS

This case-control study points out angiotensin-converting enzyme inhibitors and female sex as risk factors of bradykinin AE associated with thrombolysis for ischemic stroke.

A Case of Oropharyngeal Angioedema Following Intravenous Recombinant Tissue Plasminogen Activator (rt-PA) and Mechanical Thrombectomy

A 72-year-old housewife presented with ischemic cerebrovascular stroke. Intravenous thrombolysis using recombinant tissue plasminogen activator (rt-PA) followed by mechanical thrombectomy under general anesthesia were attempted. The patient developed stridor and tongue swelling, in addition to hypotension and bradycardia, 60 min after completion of the rt-PA infusion. The airway was intubated, and intramuscular adrenaline, together with intravenous hydrocortisone and diphenhydramine, were administered. On the second day, the tongue edema subsided, and the cuff leak test was negative. However, extubation was not attempted due to the development of brain edema. A tracheostomy was later performed, and the patient was weaned off mechanical ventilation.

Prognostic value of subclinical thyroid dysfunction in ischemic stroke patients treated with intravenous thrombolysis

Data regarding the association between subclinical thyroid dysfunction and clinical outcomes in ischemic stroke patients with intravenous thrombolysis (IVT) are limited. We aimed to investigate the predictive value of subclinical thyroid dysfunction in END, functional outcome and mortality at 3 months among IVT patients. We prospectively recruited 563 IVT patients from 5 stroke centers in China. Thyroid function status was classified as subclinical hypothyroidism, subclinical hyperthyroidism (SHyper) and euthyroidism. The primary outcome was END, defined as ≥ 4 point in the NIHSS score within 24 h after IVT. Secondary outcomes included 3-month functional outcome and mortality. Of the 563 participants, END occurred in 14.7%, poor outcome in 50.8%, and mortality in 9.4%. SHyper was an independent predictor of END [odd ratio (OR), 4.35; 95% confidence interval [CI], 1.86–9.68, P = 0.003], 3-month poor outcome (OR, 3.24; 95% CI, 1.43–7.33, P = 0.005) and mortality [hazard ratio, 2.78; 95% CI, 1.55–5.36, P = 0.003]. Subgroup analysis showed that there was no significant relationship between SHyper and clinical outcomes in IVT patients with endovascular therapy. In summary, SHyper is associated with increased risk of END, and poor outcome and mortality at 3 months in IVT patients without endovascular therapy.

Angioedema in Stroke Patients With Thrombolysis

Background and Purpose- Oral angioedema (OA) is a rare but life-threatening complication in patients with ischemic stroke receiving intravenous thrombolysis with r-tPA (recombinant tissue-type plasminogen activator). This study intended to determine associations between thrombolysis-related OA and ischemic stroke lesion sites using a voxel-wise lesion analysis. Methods- Prospective registry data were used to identify ischemic stroke patients with thrombolysis-related OA between 2002 and 2018. For the study registry, ethics approval was obtained by the Ethics Committee of the Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg (clinical registry registration: 377_17Bc). Ischemic stroke patients with thrombolysis treatment but without OA admitted in the years 2011 and 2012 comprised the control group. Ischemic lesions were manually outlined on magnetic resonance imaging (1.5T or 3T) or computed tomographic scans and transformed into stereotaxic space. We determined the lesion overlap and compared the absence or presence of OA voxel-wise between patients with and without lesions in a given voxel using the Liebermeister test. Stroke severity was rated using the National Institutes of Health Stroke Scale score, and blood pressure, heart rate, blood glucose levels, and body temperature were determined on admission. Results- Fifteen ischemic stroke patients with thrombolysis-related OA were identified. The voxel-wise analysis yielded associations between OA and ischemic lesions in the insulo-opercular region with a right hemispheric dominance. Mean blood pressure was significantly lower in patients with OA than in controls. Age, National Institutes of Health Stroke Scale scores, infarct volumes, heart rate, and blood glucose levels did not differ between patients with and without OA. Conclusions- The voxel-wise analysis linked thrombolysis-related OA to right insulo-opercular lesions. The lower blood pressure in patients with thrombolysis-related OA may reflect bradykinin effects causing vasodilatation and increasing vascular permeability.

Angioedema after thrombolysis with tissue plasminogen activator: an airway emergency

Recombinant tissue plasminogen activator (rtPA), an enzyme that catalyzes the conversion of plasminogen to plasmin resulting in fibrinolysis, is used for the treatment of acute ischemic strokes. The use of this medication is not without complication. One complication of this therapy is angioedema. This complication can be life-threatening if not recognized quickly. However, the potential for the development of angioedema after rtPA administration is not widely known. This is a case of a 60-year-old man who suffered an acute ischemic stroke and was given rtPA. The patient subsequently developed rapidly progressing angioedema leading to airway compromise. The patient was intubated with some difficulty and the angioedema improved and the patient was able to be extubated the next day. Angioedema secondary to administration of rtPA is thought to be bradykinin mediated, but the exact mechanism is unknown. Treatment with FFP, Icatibant, Ecallantide or a C1-esterase inhibitor can be considered.

Comparing Pathways of Bradykinin Formation in Whole Blood From Healthy Volunteers and Patients With Hereditary Angioedema Due to C1 Inhibitor Deficiency

Multiple pathways have been proposed to generate bradykinin (BK)-related peptides from blood. We applied various forms of activation to fresh blood obtained from 10 healthy subjects or 10 patients with hereditary angioedema (HAE-1 or −2 only) to investigate kinin formation. An enzyme immunoassay for BK was applied to extracts of citrated blood incubated at 37°C under gentle agitation for 0–2 h in the presence of activators and/or inhibitory agents. Biologically active kinins in extracts were corroborated by c-Fos accumulation in HEK 293a cells that express either recombinant human B₂ or B₁ receptors (B₂R, B₁R). Biological evidence of HAE diagnostic and blood cell activation was also obtained. The angiotensin converting enzyme inhibitor enalaprilat, without any effect per se, increased immunoreactive BK (iBK) concentration under active stimulation of blood. Tissue kallikrein (KLK-1) and Kontact-APTT, a particulate material that activates the contact system, rapidly (5 min) and intensely (>100 ng/mL) induced similar iBK generation in the blood of control or HAE subjects. Tissue plasminogen activator (tPA) slowly (≥1 h) induced iBK generation in control blood, but more rapidly and intensely so in that of HAE patients. Effects of biotechnological inhibitors indicate that tPA recruits factor XIIa (FXIIa) and plasma kallikrein to generate iBK. KLK-1, independent of the contact system, is the only stimulus leading to an inconsistent B₁R stimulation. Stimulating neutrophils or platelets did not generate iBK. In the HAE patients observed during remission, iBK formation capability coupled to B₂R stimulation appears largely intact. However, a selective hypersensitivity to tPA in the blood of HAE patients suggests a role of plasmin-activated FXIIa in the development of attacks. Proposed pathways of kinin formation dependent on blood cell activation were not corroborated.

Acute diffuse and transient thyroid swelling after intravenous thrombolysis for acute ischemic stroke: A case report

RATIONALE

Intravenous thrombolysis is the primary therapy for acute ischemic stroke (AIS), but it has some complications, including symptomatic intracranial hemorrhage, orolingual angioedema, and extracranial bleeding. However, thyroid disorders associated with thrombolysis are very rare.

PATIENT CONCERNS

A 56-year-old man developed acute pain and neck swelling after thrombolysis with recombinant tissue plasminogen activator.

DIAGNOSES

Ultrasound revealed a diffusely enlarged thyroid with linear hypoechoic areas throughout the entire gland, resembling a "cracked" appearance.

INTERVENTIONS

The patient was treated conservatively with cold packs and observed closely. Follow-up ultrasound was made.

OUTCOMES

A few hours later, pain and swelling disappeared completely. A repeat ultrasound revealed complete recovery of thyroid volume and aspect on the next day.

LESSONS

After intravenous thrombolysis for AIS, several life-threatening complications, such as hemorrhage and orolingual angiedema, also can cause neck swelling. Urgent intubation and surgery may be required. However, the rare complication, acute diffuse thyroid swelling, is self-limiting and nonfatal and conservative treatment is sufficient. Neck ultrasound is helpful in rapidly distinguishing these complications.

Impact of Bradykinin Generation During Thrombolysis in Ischemic Stroke

Ischemic stroke is one of the leading causes of death and disability worldwide. Current medical management in the acute phase is based on the activation of the fibrinolytic cascade by intravenous injection of a plasminogen activator (such as tissue-type plasminogen activator, tPA) that promotes restauration of the cerebral blood flow and improves stroke outcome. Unfortunately, the use of tPA is associated with deleterious effects such as hemorrhagic transformation, symptomatic brain edema, and angioedema, which limit the efficacy of this therapeutic strategy. Preclinical and clinical evidence suggests that intravenous thrombolysis generates large amounts of bradykinin, a peptide with potent pro-inflammatory, and pro-edematous effects. This tPA-triggered generation of bradykinin could participate in the deleterious effects of thrombolysis and is a potential target to improve neurological outcome in tPA-treated patients. The present review aims at summarizing current evidence linking thrombolysis, bradykinin generation, and neurovascular damage.

Angiotensin-converting Enzyme Inhibitor and Other Drug-associated Angioedema

Nonsteroidal antiinflammatory agents, β-lactam antibiotics, non-β lactam antibiotics, and angiotensin-converting enzyme inhibitors are the most common classes of drugs that cause angioedema. Drug-induced angioedema is known to occur via mechanisms mediated by histamine, bradykinin, or leukotriene, and an understanding of these mechanisms is crucial in guiding therapeutic decisions. Nonallergic angioedema occurs in patients with genetic variants that affect metabolism or synthesis of bradykinin, substance P, prostaglandins, or leukotrienes, or when patients are taking drugs that have synergistic mechanisms. The mainstay in treatment of nonallergic drug-induced angioedema is cessation of the offending agents.

Rivaroxaban-Induced Hypersensitivity Syndrome

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The Effects of the Contact Activation System on Hemorrhage

The contact activation system (CAS) exerts effects on coagulation via multiple mechanisms, which modulate both the intrinsic and extrinsic coagulation cascades as well as fibrinolysis and platelet activation. While the effects of the CAS on blood coagulation measured as activated partial thromboplastin time shortening are well documented, genetic mutations that result in deficiencies in the expression of either plasma prekallikrein (PPK) or factor XII (FXII) are not associated with spontaneous bleeding or increased bleeding risk during surgery. Deficiencies in these proteins are often undiagnosed for decades and detected later in life during routine coagulation assays without an apparent clinical phenotype. Increased interest in the CAS as a potentially safe target for antithrombotic therapies has emerged, in large part, from studies on animal models with provoked thrombosis, which have shown that deficiencies in PPK or FXII can reduce thrombus formation without increasing bleeding. Gene targeting and pharmacological studies in healthy animals have confirmed that PPK and FXII blockade does not cause coagulopathies. These findings support the conclusion that CAS is not required for hemostasis. However, while deficiencies in FXII and PPK do not significantly affect bleeding associated with peripheral wounds, recent reports have demonstrated that these proteins can promote hemorrhage in the retina and brain. Intravitreal injection of plasma kallikrein (PKal) induces retinal hemorrhage and intracerebral injection of PKal increases intracranial bleeding. PPK deficiency and PKal inhibition ameliorates hematoma formation following cerebrovascular injury in diabetic animals. Moreover, both PPK and FXII deficiency are protective against intracerebral hemorrhage caused by tissue plasminogen activator-mediated thrombolytic therapy in mice with thrombotic middle cerebral artery occlusion. Thus, while the CAS is not required for hemostasis, its inhibition may provide an opportunity to reduce hemorrhage in the retina and brain. Characterization of the mechanisms and potential clinical implications associated with the effects of the CAS on hemorrhage requires further consideration of the effects of PPK and FXII on hemorrhage beyond their putative effects on coagulation cascades. Here, we review the experimental and clinical evidence on the effects of the CAS on bleeding and hemostatic mechanisms.

Plasma kallikrein mediates brain hemorrhage and edema caused by tissue plasminogen activator therapy in mice after stroke

Thrombolytic therapy using tissue plasminogen activator (tPA) in acute stroke is associated with increased risks of cerebral hemorrhagic transformation and angioedema. Although plasma kallikrein (PKal) has been implicated in contributing to both hematoma expansion and thrombosis in stroke, its role in the complications associated with the therapeutic use of tPA in stroke is not yet available. We investigated the effects of tPA on plasma prekallikrein (PPK) activation and the role of PKal on cerebral outcomes in a murine thrombotic stroke model treated with tPA. We show that tPA increases PKal activity in vitro in both murine and human plasma, via a factor XII (FXII)-dependent mechanism. Intravenous administration of tPA increased circulating PKal activity in mice. In mice with thrombotic occlusion of the middle cerebral artery, tPA administration increased brain hemorrhage transformation, infarct volume, and edema. These adverse effects of tPA were ameliorated in PPK (Klkb1)-deficient and FXII-deficient mice and in wild-type (WT) mice pretreated with a PKal inhibitor prior to tPA. tPA-induced brain hemisphere reperfusion after photothrombolic middle cerebral artery occlusion was increased in Klkb1^-/- mice compared with WT mice. In addition, PKal inhibition reduced matrix metalloproteinase-9 activity in brain following stroke and tPA therapy. These data demonstrate that tPA activates PPK in plasma and PKal inhibition reduces cerebral complications associated with tPA-mediated thrombolysis in stroke.

Hyperfibrinolysis increases blood–brain barrier permeability by a plasmin- and bradykinin-dependent mechanism

Hydrodynamic transfection of plasmids encoding for plasminogen activators leads to a hyperfibrinolytic state in mice. Hyperfibrinolysis increases BBB permeability via a plasmin- and bradykinin-dependent mechanism.

Orolingual Angioedema During or After Thrombolysis for Cerebral Ischemia

Background and Purpose—

Orolingual angioedema (OLAE) is a life-threatening complication of intravenous thrombolysis. Our objective was to compare outcomes of patients with and without OLAE.

Methods—

We prospectively included consecutive patients who received intravenous thrombolysis for cerebral ischemia at Lille University Hospital. We examined tongue and lips every 15 minutes during thrombolysis and ≤30 minutes after. We evaluated the 3-month outcome with the modified Rankin scale (mRS) and compared outcomes of patients with and without OLAE.

Results—

Of 923 consecutive patients, 20 (2.2%) developed OLAE. None of them needed oro-tracheal intubation. They were more likely to be under angiotensin-converting enzyme inhibitors (adjusted odds ratio [adjOR], 3.9; 95% confidence interval [CI], 1.6–9.7; P =0.005) to have total insular infarcts (OR, 5.0; 95% CI, 1.5–16.5; P =0.004) and tended to develop more symptomatic intracerebral hemorrhages. Results concerning angiotensin-converting enzyme inhibitors were not modified after adjustment for propensity scores (OR, 4.4; 95% CI, 1.6–11.9; P =0.004) or matched analysis based on propensity scores (OR, 3.4; 95% CI, 1.3–8.1; P =0.010). Patients with OLAE did not significantly differ at 3 months for the proportion of patients with mRS score of 0 to 1 (adjOR, 0.9; 95% CI, 0.3–2.1), mRS score of 0 to 2 (adjOR, 0.8; 95% CI, 0.1–1.8), and death (adjOR, 1.1; 95% CI, 0.3–3.8).

Conclusions—

OLAE occurs in 1 of 50 patients who receive intravenous thrombolysis, 1 of 10 in case of total insular infarct, and 1 of 6 if they are under angiotensin-converting enzyme inhibitors. Their long-term outcome does not differ from that of other patients.

The isolated human umbilical vein as a bioassay for kinin-generating proteases: An in vitro model for therapeutic angioedema agents

AIMS

The isolated human umbilical vein is a robust contractile bioassay for ligands of the bradykinin (BK) B2 receptor (B2R), also extendable to B1 receptor (B1R) pharmacology. We hypothesized that, as a freshly isolated vessel, it also contains traces of plasma proteins that may confer responses to exogenous proteases via the formation of kinins.

MAIN METHODS

Rings of human umbilical veins were mounted in organ baths containing Krebs buffer maintained at 37°C and purified proteases were introduced in the bathing fluid along with additional drugs/proteins that permit mechanistic analysis of effects.

KEY FINDINGS

The previously described contractile response to human recombinant tissue kallikrein (KLK-1, 1-10nM) is not influenced by metabolic inhibitors, suggesting its dependence on a preexisting reservoir of low molecular weight-kininogen (LK). Active plasma kallikrein (apK, ≤5nM) was inactive in fresh tissues, unless high molecular weight-kininogen (HK, 39-197nM) replenishment was applied. The effects of KLK-1 and HK+apK are abolished by pretreating tissues with icatibant, but not with tranexamic acid. C1-esterase inhibitor inhibited only HK+apK. Purified plasmin and neutrophil proteinase-3 produced small contractions in the presence of HK only, and tissue plasminogen activator, none. B1R stimulation was pharmacologically evidenced in response to KLK-1 if LK was supplied.

SIGNIFICANCE

The pharmacology of KLK-1 and HK+apK in the human isolated umbilical vein is essentially based on the activity of locally generated kinins and this assay models the inhibitory action of some therapeutic agents active in angioedema states. Proteases that indirectly generate kinins have little activity in the system.

Cardiovascular Instability Preceded by Orolingual Angioedema after Alteplase Treatment

An 87-year-old man taking antihypertensive medications, including 10 mg enalapril, daily visited our hospital complaining of motor aphasia, dysarthria, and right hemiparesis. Magnetic resonance imaging revealed an ischemic lesion in the left frontal lobe including the insular cortex and severe stenosis of the left middle cerebral artery. After he received intravenous alteplase infusion, he developed orolingual angioedema followed by transient bradycardia with subsequent hypotension, resulting in the deterioration of his neurological signs and expansion of the ischemic lesion. Orolingual angioedema after intravenous alteplase infusion may follow cardiovascular instability and disease progression in stroke patients.

Neuropeptides: metabolism to bioactive fragments and the pharmacology of their receptors

The proteolytic processing of neuropeptides has an important regulatory function and the peptide fragments resulting from the enzymatic degradation often exert essential physiological roles. The proteolytic processing generates, not only biologically inactive fragments, but also bioactive fragments that modulate or even counteract the response of their parent peptides. Frequently, these peptide fragments interact with receptors that are not recognized by the parent peptides. This review discusses tachykinins, opioid peptides, angiotensins, bradykinins, and neuropeptide Y that are present in the central nervous system and their processing to bioactive degradation products. These well-known neuropeptide systems have been selected since they provide illustrative examples that proteolytic degradation of parent peptides can lead to bioactive metabolites with different biological activities as compared to their parent peptides. For example, substance P, dynorphin A, angiotensin I and II, bradykinin, and neuropeptide Y are all degraded to bioactive fragments with pharmacological profiles that differ considerably from those of the parent peptides. The review discusses a selection of the large number of drug-like molecules that act as agonists or antagonists at receptors of neuropeptides. It focuses in particular on the efforts to identify selective drug-like agonists and antagonists mimicking the effects of the endogenous peptide fragments formed. As exemplified in this review, many common neuropeptides are degraded to a variety of smaller fragments but many of the fragments generated have not yet been examined in detail with regard to their potential biological activities. Since these bioactive fragments contain a small number of amino acid residues, they provide an ideal starting point for the development of drug-like substances with ability to mimic the effects of the degradation products. Thus, these substances could provide a rich source of new pharmaceuticals. However, as discussed herein relatively few examples have so far been disclosed of successful attempts to create bioavailable, drug-like agonists or antagonists, starting from the structure of endogenous peptide fragments and applying procedures relying on stepwise manipulations and simplifications of the peptide structures.

Incidence, predictors and clinical characteristics of orolingual angio-oedema complicating thrombolysis with tissue plasminogen activator for ischaemic stroke

BACKGROUND

Orolingual angio-oedema is a recognised complication of tissue plasminogen activator (tPA) for ischaemic stroke. We investigated its incidence, clinical characteristics and relationship with other factors in patients receiving tPA at a UK centre.

METHODS

530 consecutive patients (median age 70 years) receiving tPA treatment for confirmed ischaemic stroke were included. Cases were defined as those developing angio-oedema within 24 h of initiation of tPA. Angio-oedema was retrospectively classified as mild, moderate or severe using predefined criteria. The primary analysis was the association between prior ACE inhibitor (ACE-I) treatment and angio-oedema.

RESULTS

Orolingual angio-oedema was observed in 42 patients (7.9%; 95% CI 5.5% to 10.6%), ranging from 5 to 189 min after initiation of tPA (median 65 min). 12% of the angio-oedema cases were severe (1% of all patients treated with tPA), requiring urgent advanced airway management. 172 patients (33%) were taking ACE-I. In multifactorial analyses, only prior ACE-I treatment remained a significant independent predictor of angio-oedema (odds ratio (OR) 2.3; 95% CI 1.1 to 4.7).

CONCLUSIONS

Angio-oedema occurs more frequently than previously reported and is associated with preceding ACE-I treatment. Angio-oedema may be delayed and progress to life-threatening airway compromise, which has implications for the assessment and delivery of thrombolysis.

[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.

Angioedema in the neurointerventional suite

A 68-year-old woman with acute ischemic stroke presented for mechanical thrombectomy, after failed thrombolysis with intravenous recombinant tissue plasminogen activator. The procedure was completed successfully with dexmedetomidine infusion. However, she developed acute angioedema toward the end of the procedure requiring emergent fiberoptic-guided endotracheal intubation. Angioedema has been reported to occur after administering intravenous recombinant tissue plasminogen activator with an incidence of 1.3%-5.1% in patients with acute stroke.

Onset of Orolingual Angioedema After Treatment of Acute Brain Ischemia with Alteplase Depends on the Site of Brain Ischemia: A Meta-analysis

Background:

Alteplase is used to treat acute ischemic stroke. However, it has several documented adverse effects, including the development of orolingual angioedema (OA). Although, OA is a rare side-effect, it is thought to be life-threatening and is difficult to treat. Until date, little is known about this condition and a better understanding of OA may contribute to improve the morbidity and mortality amongst patients that develop this condition.

Materials and Methods:

Using the PubMed and Medknow databases, we searched for peer reviewed published articles on OA after alteplase administration in 1950-2012. We gathered demographic data and investigated the relationship between the location of OA, neurological symptoms and the site of cerebral ischemia. In addition, we studied the effects of hypertensive premedication on OA development. We identified 19 published manuscripts that fulfilled our search criteria. These manuscripts reported 41 cases of OA after alteplase administration.

Results:

We found that this condition is associated with cerebral ischemia (P < 0.012) and that 65.9% (n = 27) of patients who developed OA had a hypertensive drug as a premedication.

Conclusions:

Although OA is a rare side-effect of alteplase, it can occur depending upon the localization of acute cerebral ischemia.

Anaphylactic shock associated with intravenous thrombolytics

Adverse events including intracerebral hemorrhage and reperfusion arrhythmias are well known to occur with thrombolytic therapy. We report a case report of anaphylactic reaction directly attributable to intravenous (IV) recombinant tissue plasminogen activator and identify additional cases through review of the Food and Drug Administration Adverse Event Reporting System. A systematic review of Adverse Event Reporting System was performed for allergic adverse events occurring in conjunction with IV thrombolytics. We reviewed 924 adverse events which occurred between 2004 and 2012 that were associated with thrombolytics. We subsequently acquired detailed individual safety reports of 33 cases in which allergic events were documented. Out of the 33 reports, there were 12 cases (age range, 57-93 years) of adverse allergic reaction directly attributable to IV thrombolytics. Allergic reactions included angioedema, facial swelling, urticaria, skin rash, cutaneous hypesthesia, hypotension, anaphylactic shock, and death. Of the patients who were reported to suffer from allergic adverse events, 11 received IV alteplase and 1 received IV reteplase. Most reactions associated with IV alteplase resolved with withdrawal of medication and treatment with diphenhydramine and steroids ± epinephrine. There was 1 death directly attributable to allergic reaction in a patient who received IV reteplase for MI.Although IV alteplase is identical to endogenous tissue plasminogen activator, it appears to be the most common cause of allergic reaction among currently used thrombolytics, with or without concomitant administration of angiotensin-converting enzyme inhibitors. A greater awareness among physicians may result in prompt recognition and treatment.