Hypotensive reaction during staphylococcal protein A column therapy in a patient with anomalous degradation of bradykinin and Des-Arg9-bradykinin after contact activation

Clinical Pattern in Hypotensive Transfusion Reactions

BACKGROUND

Hypotensive transfusion reactions (HyTRs) may be underreported and have been associated with patients taking angiotensin-converting enzyme inhibitors (ACEIs) receiving poststorage leukoreduced blood products through negatively charged filters. Although bedside leukoreduction is no longer commonplace, HyTRs still occur and are insufficiently characterized in the prestorage leukoreduction era. We describe recently reported cases at our institution.

METHODS

We reviewed transfusion reaction records at Stanford Healthcare from January 2014 to April 2015. HyTRs were defined by National Health Safety Network Hemovigilance Module classification.

RESULTS

Eleven HyTRs occurred in 10 patients. All were adults (mean age 71.7 years; range 45-92 years), 7 were male, and all underwent major surgery 0 to 2 days before the reaction. Nine patients underwent cardiac or vascular surgery, and all 10 were taking ACEIs with the last dose taken within 48 hours of the transfusion reaction in 9 patients. Nine patients were on extracorporeal circuits within 24 hours before the reaction (median duration 180 minutes; range 87-474 minutes). In 5 reactions, the implicated unit was restarted with resultant recurrent hypotension. Implicated units included 9 packed red blood cells, 1 apheresis platelet, and 1 plasma frozen within 24 hours.

CONCLUSIONS

Contrary to what has been previously reported in the era of prestorage leukoreduction, HyTRs at our institution showed consistent patterns in patients at risk. Patients scheduled to undergo major surgery with cardiopulmonary bypass may benefit from earlier preoperative cessation of ACEIs or temporarily switching to an alternative drug class.

Postinfectious Hemolytic Uremic Syndrome

Post-infectious hemolytic uremic syndrome (HUS) is caused by specific pathogens in patients with no identifiable HUS-associated genetic mutation or autoantibody. The majority of episodes is due to infections by Shiga toxin (Stx) producing Escherichia coli (STEC). This chapter reviews the epidemiology and pathogenesis of STEC-HUS, including bacterial-derived factors and host responses. STEC disease is characterized by hematological (microangiopathic hemolytic anemia), renal (acute kidney injury) and extrarenal organ involvement. Clinicians should always strive for an etiological diagnosis through the microbiological or molecular identification of Stx-producing bacteria and Stx or, if negative, serological assays. Treatment of STEC-HUS is supportive; more investigations are needed to evaluate the efficacy of putative preventive and therapeutic measures, such as non-phage-inducing antibiotics, volume expansion and anti-complement agents. The outcome of STEC-HUS is generally favorable, but chronic kidney disease, permanent extrarenal, mainly cerebral complication and death (in less than 5 %) occur and long-term follow-up is recommended. The remainder of this chapter highlights rarer forms of (post-infectious) HUS due to S. dysenteriae, S. pneumoniae, influenza A and HIV and discusses potential interactions between these pathogens and the complement system.

Heparin-induced anaphylactic and anaphylactoid reactions: two distinct but overlapping syndromes

BACKGROUND

Heparin-induced anaphylactic and anaphylactoid reactions are of increasing clinical and scientific interest, particularly given the recent identification of a syndrome of heparin-induced anaphylaxis due to oversulfated chondroitin sulfate (OSCS), a contaminant in certain heparin preparations. However, heparin-induced anaphylactoid reactions also have been reported to be a consequence of immune-mediated heparin-induced thrombocytopenia (HIT).

OBJECTIVE

To summarize the clinical features and pathophysiology of two distinct disorders, HIT-associated anaphylactoid reactions as well as anaphylaxis resulting from OSCS-contaminated heparin.

METHODS

We review literature describing these two types of heparin-induced anaphylactic and anaphylactoid reactions, and seek potential pathophysiologic links between them.

RESULTS

Intravenous bolus heparin administered to patients with circulating 'HIT antibodies', usually as a result of recent heparin therapy, can produce anaphylactoid reactions, probably as a consequence of in vivo activation of platelets and, possibly, leukocytes. Affected patients often evince fever/chills, hypertension and/or acute respiratory compromise ('pseudo-pulmonary embolism'). In contrast, heparin-induced anaphylaxis is caused by activation of the contact system, with formation of vasoactive kinins (bradykinin, des-arg(9)-bradykinin). This latter syndrome has been linked in an epidemic form to administration of OSCS-contaminated heparin; these reactions feature prominent hypotension and laryngeal edema. Hemodialysis patients are at increased risk for both syndromes. There is evidence that OSCS-contaminated heparin itself increases the risk of HIT compared with non-contaminated heparin.

CONCLUSION

Two distinct syndromes of heparin-induced anaphylaxis and anaphylactoid reactions exist. These seem to share certain epidemiologic features, given that OSCS-contaminated heparin can produce anaphylaxis through contact system activation but also could increase risk of HIT and HIT-associated anaphylactoid reactions.

Acute hypotensive transfusion reaction during liver transplantation in a patient on angiotensin converting enzyme inhibitors from low aminopeptidase P activity

Acute hypotensive transfusion reactions are newly characterized transfusion reactions in which hypotension is the prominent feature. The pathophysiology of acute hypotensive transfusion reactions is related to the bradykinin function and its metabolism. A liver transplant recipient on treatment with an angiotensin converting enzyme inhibitor developed sudden hypotension, that is, systolic pressure of 60 mm Hg, after receiving 200 mL of a blood product mixture without significant surgical blood loss. He responded to the resuscitation measure, although hypotension developed again after a challenge transfusion of 200 mL of the blood mixture. A severe hypotensive reaction to the blood transfusion and diffuse bleeding from the dissection surfaces forced the transplantation to be aborted after the common bile duct had been divided. We hypothesized that the patient had an acute hypotensive transfusion reaction due to disordered bradykinin metabolism. Analysis of his blood showed low levels of both angiotensin converting enzyme and aminopeptidase P enzyme activity, confirming that the patient experienced an acute hypotensive transfusion reaction that was due to the use of the angiotensin converting enzyme inhibitor and was precipitated by an abnormality in the metabolic enzyme pathway. It is recommended to discontinue angiotensin converting enzyme inhibitors and switch to a different class of antihypertensive medications for patients with a high Model for End-Stage Liver Disease score on the waiting list for liver transplantation.

Generation of kinins during preparation and storage of whole blood?derived platelet concentrates

BACKGROUND

Leukoreduction of platelet (PLT) concentrates (PCs) may be associated with hypotension in recipients, and a role for bradykinin (BK)-related peptides has been proposed for this side effect.

STUDY DESIGN AND METHODS

The concentration of BK and one of its vasoactive metabolites, des-arginine(9)-BK (des-Arg(9)-BK), was measured in a large number of PCs as a function of leukoreduction and storage duration with specific enzyme immunoassays and complementary techniques.

RESULTS

On Day 0 of storage, kinins were detected in leukoreduced and unfiltered PCs at a concentration lower than 100 pg per mL. During storage, both kinin levels peaked on Day 5 of storage, with a concentration higher than 1 ng per mL in 22 percent of PCs whether filtered on Day 0 or not. Physicochemical and pharmacologic characterizations of immunoreactive kinins confirm their nature. In vitro activation of the contact system of the corresponding PLT-poor plasma showed that a high kinin concentration on Day 5 of the storage corresponded with a low kinin-forming capacity of plasma. On Day 7, BK was no longer elevated presumably due to its degradation and the depletion of kinin-forming capacity of the plasma in stored PCs. The activities of metallopeptidases that metabolize BK-related peptides in plasma from PCs were at levels similar to those recorded in the plasma of a normal reference population and were unaffected by storage.

CONCLUSION

Storage of PCs contributes to the hydrolysis of high-molecular-weight kininogen and generation of pharmacologically relevant BK levels that might pose a hazard in susceptible patients.

Safety and Tolerability of Long Lasting LDL-apheresis in Familial Hyperlipoproteinemia

The aim of this work is to arbitrate the incidence of side effects and tolerability of long lasting LDL-apheresis in familial hyperlipoproteinemia. 1200 procedures were performed and the last 463 of them were evaluated. An immunoadsorption method of LDL-apheresis was used (continuous blood cell separator Cobe Spectra; secondary device: automated adsorption-desorption ADA, Medicap; absorption columns: Lipopak). As a whole, 6.26% adverse events were found and subsequently resolved by standard symptomatic therapy. Vaso-vagal reactions (symptoms of neurovegetative lability) were the most common adverse effects, presented as malaise, weakness, slight and short-term drop in blood pressure or other general signs. They were all well controlled by symptomatic therapy. We conclude that LDL-apheresis in the hands of experienced personnel is a safe procedure. An acceptable procedure duration limit, balancing the possibility to achieve a targeted cholesterol level while still maintaining an acceptable patient tolerance, was confirmed to be 4 hours.

Kinin-dependent hypersensitivity reactions in hemodialysis: metabolic and genetic factors

Although the association of angiotensin I-converting enzyme inhibitors (ACEis) with a negatively charged membrane is thought to be responsible for hypersensitivity reactions (HSRs) during hemodialysis, we hypothesize that these complications are due to changes in plasma aminopeptidase P (APP) activity and genotype. To test this hypothesis, we measured plasma APP activity in 14 patients who suffered HSR (HSR+) while dialyzed with an AN69 membrane and simultaneously treated with an ACEi. APP activity was also studied in a control group (n=39) dialyzed under the same conditions, but who did not suffer any side effect (HSR-). We found significantly decreased plasma APP activity (P=0.013) in HSR+ subjects as well as altered degradation of endogenous des-Arginine(9)-bradykinin, with a significantly lower beta value (P<0.001). The same analytical approach was taken in 171 relatives of HSR+ patients. Variance component analysis suggested that genetic differences may explain 61% of the phenotypic variability of plasma APP activity (P<0.001) and the kinetic parameters that characterized kinin degradation. We also showed that the C-2399A single-nucleotide polymorphism at the XPNPEP2 locus was a significant predictor of APP activity in the 39 HSR- controls (P=0.029). Furthermore, a recessive genetic model for the A allele disclosed a significant difference in mean APP activity by genotype (P<0.001). Finally, our study defined the nonspecific inhibition of recombinant APP by some ACEis. In conclusion, this paper highlights the complexity of HSR in hemodialysis, suggesting, as with angioedema, that these rare, but life-threatening adverse events are governed by several metabolic and genetic factors.

Aspect multifactoriel des effets secondaires aigus des inhibiteurs de l′enzyme de conversion de l′angiotensine

Angiotensin converting enzyme inhibitors are a class of drugs successfully used in the treatment of cardiovascular diseases. Despite their effectiveness, treatment with these drugs is characterized by chronic and acute side effects with variable expression depending on the clinical context. Angioedema occurs in patients with hypertension or heart failure. Anaphylactoid reaction is also reported in hemodialysis patients and severe hypotensive reaction in patients receiving transfused blood products and plasmapheresis. In this paper, we describe the role of kinins and metallopeptidases in the pathophysiology of these acute side effects. We also propose different experimental and clinical evidences which plead for an ecogenetic nature of these rare but life-threatening events.

The kallikrein-kinin system: current and future pharmacological targets

The kallikrein-kinin system is an endogenous metabolic cascade, triggering of which results in the release of vasoactive kinins (bradykinin-related peptides). This complex system includes the precursors of kinins known as kininogens and mainly tissue and plasma kallikreins. The pharmacologically active kinins, which are often considered as either proinflammatory or cardioprotective, are implicated in many physiological and pathological processes. The interest of the various components of this multi-protein system is explained in part by the multiplicity of its pharmacological activities, mediated not only by kinins and their receptors, but also by their precursors and their activators and the metallopeptidases and the antiproteases that limit their activities. The regulation of this system by serpins and the wide distribution of the different constituents add to the complexity of this system, as well as its multiple relationships with other important metabolic pathways such as the renin-angiotensin, coagulation, or complement pathways. The purpose of this review is to summarize the main properties of this kallikrein-kinin system and to address the multiple pharmacological interventions that modulate the functions of this system, restraining its proinflammatory effects or potentiating its cardiovascular properties.

In vitro and in vivo evaluation of Adacolumn cytapheresis in healthy subjects

Adacolumn is a medical device for adsorptive cytapheresis. It has been developed for selective adsorption of granulocytes and monocytes from peripheral blood of patients with immune disorders, such as autoimmune diseases and chronic inflammatory diseases. A double blind sham-controlled crossover study design was used in order to evaluate in vivo biological responses of leukocytes as well as biocompatibility during and after Adacolumn cytapheresis in healthy volunteers. In addition, experiments were undertaken to further evaluate leukocyte reactions to Adacolumn carrier (G-1: cellulose diacetate) beads in vitro. Six healthy volunteers, 4 males and 2 females, with a mean age of 26.7 years were randomly assigned to one of the two treatment arms in a crossover fashion. Three subjects received a single Adacolumn treatment, followed by a single sham treatment at an interval of 7 days. The other three subjects received the two treatments in reverse order. All subjects were followed up 7 days after the last treatment. Additionally, in vitro investigations were carried out using blood from the healthy donors to examine the effect of G-1 beads on granulocyte functions. In vitro exposure of human peripheral blood to G-1 beads caused downregulation of L-selectin expression and upregulation of Mac-1 expression on granulocytes, leading to a marked reduction of adhesive capacity of granulocytes to endothelial cells. The exposure also led to decreased granulocyte chemotactic activity to IL-8. The number of granulocytes and monocytes clearly decreased during Adacolumn cytapheresis. Granulocytes showed marked phenotypic changes of L-selectin(Low) and Mac-1(Hi) after passing through Adacolumn in vivo. Expression of TNF-alpha and chemokine receptors was downregulated. In addition, TNF-alpha and IL-1beta producing capacity of peripheral blood leukocytes was decreased after Adacolumn cytapheresis and these changes lasted even one week after the cytapheresis. The level of complement fragments, C3a and C5a, increased, while bradykinin concentration did not change during Adacolumn cytapheresis. Exposure of human peripheral blood to G-1 beads, both in vitro and in vivo, caused a significant reduction of adhesive capacity and proinflammatory cytokine producing capacity of peripheral blood leukocytes. Such changes were not observed after sham apheresis. Despite complement activation, tolerability of Adacolum cytapheresis was not influenced. These findings may at least partly explain the beneficial effect of Adacolumn cytapheresis in the treatment of autoimmune diseases.

Increased C-reactive protein in ACE-inhibitor-induced angioedema

AIMS

This study was designed to identify new factors which may contribute to angiotensin-converting-enzyme-inhibitor (ACEI)-induced angioedema.

METHODS

In a retrospective cohort study we examined 25 patients who used an ACEI and presented at our emergency room with acute angioedema as well as 18 patients with unknown cause of angioedema and a total of 21 patients on ACEI-therapy without previous angioedema. We measured markers of inflammation such as acute-phase proteins (C-reactive protein, fibrinogen), leukocyte count and body temperature.

RESULTS

The mean interval between initiation of ACEI treatment and first manifestation of angioedema was 35.8 +/- 5.3 months. During symptomatic angioedema, mean plasma levels of C-reactive protein and fibrinogen were significantly increased by 7.3-fold and 1.5-fold, respectively, while leukocyte count and body temperature were normal. These changes disappeared after successful treatment of angioedema and were not found in patients with angioedema of unknown cause and those receiving ACEI without having experienced angioedema.

CONCLUSION

Our findings demonstrate for the first time that ACEI-induced angioedema is associated with strongly increased plasma levels of CRP. We suggest that CRP is involved in the pathophysiology of ACEI-induced angioedema.

[ACE inhibitor-induced angioedema in the head and neck region. A matter of time?]

BACKGROUND

Angioedema in the head and neck region is potentially life-threatening and may occur as a side effect of inhibitors of the angiotensin-converting-enzyme (ACEI). So far, little is known about the time between the first application of ACEI and the occurrence of angioedema, or of possible cofactors and laboratory changes.

MATERIAL AND METHODS

A total of 21 patients with angioedema during the course of ACEI treatment were compared to 11 patients with angioedema of unknown cause. These were retrospectively analysed for the following criteria: (1) duration of ACEI medication, (2) leading and concomitant diseases, (3) history of allergies, (4) co-medication, (5) laboratory changes, (6) treatment success, and (7) manifestation of recurrent episodes.

RESULTS

The mean interval between the initiation of ACEI therapy and the first occurrence of angioedema exceeded 2 years. Values for the acute phase proteins C-reactive protein (CRP) and fibrinogen were significantly increased in the ACEI group compared to the control group.

CONCLUSIONS

In any case of angioedema in the head and neck region, a side effect of ACEI must be taken into consideration even if the medication has been taken for months or years.

Human recombinant membrane-bound aminopeptidase P: production of a soluble form and characterization using novel, internally quenched fluorescent substrates

APP (aminopeptidase P) has the unique ability to cleave the N-terminal amino acid residue from peptides exhibiting a proline at P(1)'. Despite its putative involvement in the processing of bioactive peptides, among them the kinins, little is known about the physiological roles of both human forms of APP. The purpose of the present study is first to engineer and characterize a secreted form of hmAPP (human membrane-bound APP). Our biochemical analysis has shown that the expressed glycosylated protein is fully functional, and exhibits enzymic parameters similar to those described previously for mAPP purified from porcine or bovine lungs or expressed from a porcine clone. This soluble form of hmAPP cross-reacts with a polyclonal antiserum raised against a 469-amino-acid hmAPP fragment produced in Escherichia coli. Secondly, we synthesized three internally quenched fluorescent peptide substrates that exhibit a similar affinity for the enzyme than its natural substrates, the kinins, and a higher affinity compared with the tripeptide Arg-Pro-Pro used until now for the quantification of APP in biological samples. These new substrates represent a helpful analytical tool for rapid and reliable screening of patients susceptible to adverse reactions associated with angiotensin-converting enzyme inhibitors or novel vasopeptidase (mixed angiotensin-converting enzyme/neprilysin) inhibitors.

Hypotensive transfusion reactions can occur with blood products that are leukoreduced before storage

BACKGROUND

Leukoreduction before storage, rather than bedside white blood cell filtration, is recommended to prevent hypotensive transfusion reactions.

STUDY DESIGN AND METHODS

Investigation of hypotensive transfusion reactions during radical prostatectomy in two patients on angiotensin-converting enzyme inhibitors. In Patient A, hypotension occurred during the transfusion of each of the following blood products: 2 units of autologous blood deposited and leukoreduced (LR) before storage; 3 units of allogeneic red cells LR before storage; and 2 units of non-LR acute normovolemic hemodilution (ANH) whole blood. When each of the transfusions was stopped, the blood pressure recovered. In Patient B, hypotension occurred during the transfusion of non-LR ANH whole blood. All implicated units were administered rapidly using a blood infuser at 37 degrees C. Bradykinin (BK) and des-Arg9-BK formation and degradation and the activity of kinin-degrading metallopeptidases were measured in plasma samples from both patients.

RESULTS

Degradation of des-Arg9-BK was severely impaired and the activity of aminopeptidase P severely reduced in Patient A, but not in Patient B. BK degradation was mildly impaired in both patients.

CONCLUSION

Hypotensive reactions can occur with blood products that are LR before storage and non-LR ANH. An inherent defect in the metabolism of kinins may be a risk factor for the development of hypotensive transfusion reactions.

Regulation of the angiotensin-converting enzyme activity by a time-course hypoxia in the carotid body

Chronic hypoxia activates a local angiotensin-generating system in the carotid body. Here, we test the hypothesis that the activity of the critical enzyme for this system, angiotensin-converting enzyme (ACE), in the carotid body is subject to regulation by a time-course hypoxia. Results from the carotid body assays showed that ACE activity was markedly increased under the hypoxic stress of 7-, 14-, 21-, and 28-day exposures. The changes in ACE activity of 7-day (15.00 vs. 30.95 x 10(-5) nmol.microg(-1).min(-1)), 14-day (8.73 vs. 30.25 x 10(-5) nmol.microg(-1).min(-1)), and 21-day (11.41 vs. 31.83 x 10(-5) nmol.microg(-1).min(-1)) hypoxia treatments were enhanced significantly. However, ACE activity in 28-day (13.18 vs. 24.53 x 10(-5) nmol.microg(-1).min(-1)) hypoxia treatment was observed to increase insignificantly when compared with results in the respective control groups. Captopril inhibited all rises in ACE activity in both the control and experimental groups. Results clearly indicate an activation of the enzymatic activity of ACE, the critical enzyme for determining the conversion of angiotensin I into the physiologically active angiotensin II, by chronic hypoxia in the carotid body. An increase in the ACE activity may increase the local production of angiotensin II in the carotid body and thus its agonist action at the AT1 receptor. This may be important in the modulation of cardiopulmonary adaptation in the hypoxic ventilatory response as well as for electrolyte and water homeostasis during chronic hypoxia.