Comparison of effects of ioxaglate versus iomeprol on histamine and tryptase release in patients with ischemic cardiomyopathy

Influence of MRI contrast media on histamine release from mast cells

Background:

Mast cells, owing to diversity of secreted mediators, play a crucial role in the regulation of inflammatory response. Together with basophils, mast cells constitute a central pathogenetic element of anaphylactic (IgE-dependent) and anaphylactoid (IgE-independent) reactions. In severe cases, generalized degranulation of mast cells may cause symptoms of anaphylactic shock. The influence of the classical, iodine-based contrast media on mastocyte degranulation has been fully described. Our objective was to determine the influence of the gadolinium-based MRI contrast media on histamine release from mast cells and to compare the activity of ionic and non-ionic preparations of contrast media.

Material/Methods:

To determine the intensity of mast cell degranulation, we used an experimental model based on mastocytes isolated from rat peritoneal fluid. Purified suspensions of mast cells were incubated with various concentrations of Gd-DTPA and Gd-DTPA-BMA, and solutions of PEG 600 which served as a non-toxic osmotic stimulus. The intensity of mast cell activation was presented as mean percentage of histamine released from cells after incubation.

Results/Conclusions:

The obtained results demonstrate that both ionic and non-ionic preparations of the MRI contrast media are able to induce mast cell degranulation in vitro. It was also proved that the non-ionic MRI contrast media stimulate mast cells markedly more weakly than ionic contrast media at identical concentration. The aforementioned results may suggest a more profitable safety profile of the non-ionic contrast preparations. We may also conclude that triggering of mast cell degranulation after incubation with the solutions of MRI contrast media results from non-specific osmotic stimulation and direct toxicity of free ionic residues.

[Immediate and delayed hypersensitivity reactions to iodinated radiographic contrast agents: an update]

Diagnostic and interventional radiology of patients is nowadays crucial with increasing requirement for iodinated contrast agents infusion. Besides adverse reactions after administration of the iodinated contrast agents due to their toxicity, immediate hypersensitivity reactions and reactions resembling delayed hypersensitivity appearing from 1 hour to several days later, have been reported. Patients at high risk to develop such adverse events have to be detected on the basis of their risk factors in order to prevent or limit serious outcomes. Previous reactions to contrast media, asthma, atopy and cardiovascular disorders are risk factors for anaphylactic or anaphylactoid reactions. Female gender, age and beta-blockers increase the severity. This article aims to summarize the risk of allergic reactions related to the use of iodinated contrast agents and to suggest a way for diagnosis, treatment and prevention according to each clinical situation.

Allergy-like reactions to iodinated contrast agents. A critical analysis

Allergy-like reactions may occur following administration of iodinated contrast media (CM), mostly in at-risk patients (patients with history of previous reaction, history of allergy, co-treated with interleukin-2 or beta-blockers, etc.) but remain generally unpredictable. Severe and fatal reactions are very rare events. All categories of CM may induce such reactions, although first generation (high osmolar CM) have been found to induce a higher rate of adverse events than low osmolar CM. However, no differences were found between the two categories of CM with respect to mortality. Delayed reactions can also occur. There are no differences between the various categories of CM except for non-ionic dimers, which are more likely to induce such effect. Numerous clinical studies have evaluated the prophylactic value of drugs (mostly antihistamines and corticosteroids). Results are unclear and highly variable. Any prevention depends upon the mechanism involved. However, the mechanism of CM-induced allergy-like reaction remains disputed. Relatively recent data revived the hypothesis of a type-I hypersensitivity mechanism. Positive skin tests to CM have been reported. However, the affinity of IgE towards CM has been found to be very low in the only study which actually evaluated it. Other pathophysiological mechanisms (involving direct secretory effects on mast cells or basophils, or activation of the complement system associated or not with the plasma contact system) are also much debated. Anaphylaxis and anaphylactoid reactions are, in the end, clinically undistinguishable.

Physiology and pathophysiology of proteinase-activated receptors (PARs): role of tryptase/PAR-2 in vascular endothelial barrier function

Proteinase-activated receptor-2 (PAR-2) plays important roles in a variety of pathophysiological functions, including inflammatory responses and nociception. In this minireview, we describe the role of PAR-2 in acute inflammatory responses in lungs associated with iodinated radiographic contrast medium (RCM). Intravenous injection of RCM to rats induces lung injury characterized by vascular hyperpermeability, edema, and respiratory depression. Nafamostat, which is found to be the most potent and specific tryptase inhibitor, prevents RCM-induced lung injury. In cultured endothelial cells of human pulmonary artery and bovine aorta, RCM, when applied in combination with mast cells, disrupts barrier function evaluated by the permeability of Evans blue through a monolayer of cultured cells, which is blocked by nafamostat and mimicked by tryptase and PAR-2-activating peptide. The tryptase-induced barrier dysfunction is blocked completely by a phospholipase C inhibitor and partially inhibited by a IP(3) receptor blocker, protein kinase C inhibitor, or Rho kinase inhibitor. Morphological observations reveal the formation of actin stress fibers and disappearance of the intercellular meshwork structure of vascular endothelial-cadherin after application of RCM or PAR-2 ligands. Therefore, the release of mast cell tryptase and subsequent activation of endothelial PAR-2 are involved in acute lung injury induced by RCM.

« Allergie à l’iode » : le point sur la question

OBJECTIVE

The aim of this literature review is to suggest a diagnostic and a preventive attitude in patients having presented an immediate hypersensitivity reaction due to an iodinated drug.

DATA SOURCES

Literature review. Data were searched in the Medline database from 1967 to 2004 in English and French language. Complementary references were selected from the bibliography of selected references or from authors' personal databases. The following key-words were used separately or combined: Hypersensitivity, Immediate; Allergy; Contrast Media; Povidone-Iodine; Iodine; Iodine Compounds; Iodides; Amiodarone; Seafood, Parvalbumins; Tropomyosin.

STUDY SELECTION

Randomized studies, epidemiological studies, original articles, clinical cases, and letters to the editor were selected.

DATA SYNTHESIS

The implication of iodine has never been demonstrated during allergic hypersensitivity reactions due to iodinated drugs. However, IgE-mediated allergic hypersensitivity reactions have been published with contrast media or iodinated antiseptics and will be described in this development. In a wider sense, allergic hypersensitivity reactions due to seafood are evoked because often improperly considered as a risk factor of allergic reaction to iodinated drugs. The allergenic determinant responsible of patient sensitization is not known for iodinated contrast media, but is probably due to povidone in case of iodine povidone. In fish, the allergen is described as the protein M. There has also been strong immunological evidence that tropomyosin is a cross-reactive allergen among crustaceans and molluscs (shellfishs). In case of hypersensitivity reaction occurring with iodinated drug, an allergological assessment is required to confirm the immune mechanism, to identify the culprit drug or substance and to identify cross-reactivity especially with iodinated contrast media.

CONCLUSION

Asking a patient if he/she is "allergic to iodine" is a question that should be avoided because its significance is null. A diagnosis of drug allergy, essentially relying on clinical symptoms, biological tests and cutaneous tests, is required to take adequate preventive measures.

Clinical and Experimental Evidence for Prevention of Acute Renal Failure Induced by Radiographic Contrast Media

Acute renal failure still occurs as a complication after radiographic examination using iodinated radiocontrast medium. The incidence rate of radiocontrast medium-induced nephropathy (radiocontrast nephropathy) is low (2 - 3%) in general. However, the rate is remarkably elevated in patients with pre-existing renal insufficiency. Radiocontrast nephropathy is associated with increased morbidity and mortality, particularly in patients with percutaneous coronary interventions. Although the reduction in renal blood flow and direct toxic action on renal tubular cells are considered to be involved, little is known about the etiology of radiocontrast nephropathy. A number of agents that improve renal circulation have been clinically tested for prevention of radiocontrast nephropathy, but none of them has succeeded. Protection of renal tubular cells against oxidative stress is another approach to avoid radiocontrast nephropathy. Prophylactic effects of antioxidants such as N-acetylcysteine and ascorbic acid have been reported by several investigators, although the effectiveness of these compounds is still a matter of debate. At present, hydration is regarded as the only effective, though incomplete, prophylactic regimen for radiocontrast nephropathy. Recently, we have shown that caspase-dependent apoptosis is an important factor in the pathogenesis of radiocontrast nephropathy and clarified cellular mechanisms underlying the radiocontrast media-induced apoptosis. This review summarizes clinical and experimental evidence for the etiology and prevention of radiocontrast nephropathy.

Comparison of cellular mechanisms underlying histamine release from rat mast cells induced by ionic and nonionic radiographic contrast media

PURPOSE

To determine the cellular mechanisms underlying mast cell histamine release induced by ionic and nonionic radiographic contrast media.

MATERIALS AND METHODS

Histamine release from rat pulmonary mast cells was measured after incubation with various radiographic contrast media. The cellular cAMP content was determined by an enzymatic immunoassay.

RESULTS

Both ionic and nonionic contrast media stimulated the histamine release, although the former was more potent than the latter. Dibutyryl cAMP suppressed histamine release evoked by ionic but not nonionic contrast media in a manner dependent on A kinase. The cellular cAMP content was lowered only by ionic contrast media. However, a secretory phospholipase A2 inhibitor p-bromophenacyl bromide inhibited both ionic and nonionic contrast media-evoked histamine releases.

CONCLUSION

We demonstrated for the first time the difference and similarity in the cellular mechanisms underlying histamine release induced by ionic and nonionic contrast media, in which the reduction in cAMP was specific for ionic materials and the activation of secretory phospholipase A2 may be common to both agents.

The nonionic radiocontrast medium iopromide does not release endothelin-1 or activate cardiac mast cells during coronary angiography

BACKGROUND

High osmolal ionic radiocontrast media (RCM) cause vascular release of endothelin-1 (ET-1) and activate mast cells. Iomeprol, a nonionic RCM, has recently been reported not to activate cardiac mast cells. This coronary angiography study was performed to extend those findings using another nonionic RCM, iopromide, and to further determine whether iopromide causes release of ET-1.

METHODS

Pulmonary artery plasma ET-1, histamine and serum tryptase were determined before and 30 min following angiography with iopromide in 11 subjects. ET-1, histamine and tryptase were measured using immunoassays.

RESULTS

The concentrations of ET-1 (1.36 +/- 0.66 pg/ml), histamine (2.63 +/- 1.15 nM), and beta (<1 microg/l) as well as total tryptase (8.25 +/- 4.63 microg/l) in the preangiography samples were within the normal range. Following angiography, the concentrations of ET-1 (0.95 +/- 0.80 pg/ml), histamine (3.08 +/- 1.06 nM), and beta (<1 microg/l) and total tryptase (7.00 +/- 5.56 microg/l) were not significantly different. None of the subjects demonstrated a postangiography increase in mediator concentration.

CONCLUSIONS

This study demonstrates the lack of release of ET-1 by iopromide. The lack of cardiac mast cell activation by iopromide is consistent with the report that iomeprol also does not activate cardiac mast cells.

Roles of intracellular Ca2+ and cyclic AMP in mast cell histamine release induced by radiographic contrast media

Mast cell histamine release is considered to be associated with the etiology of anaphylactoid reactions to iodinated radiographic contrast media (RCM). In the present study, the effects of various ionic and non-ionic RCM on histamine release from mast cells were compared, and the possible mechanisms of the histamine release were subsequently determined. Both ionic (ioxaglate and amidotrizoate) and non-ionic (iohexol, ioversol, iomeprol, iopamidol and iotrolan) RCM increased histamine release from the dissociated rat pulmonary cells, whereby ionic materials were more potent than non-ionic agents. There was no significant correlation between the extent of histamine release and the osmolarity of each RCM solution. In addition, hyperosmotic mannitol solution (1000 mOsm/kg) caused no marked histamine release. Thus, it is unlikely that the hyperosmolarity of RCM solutions contributes to the histamine release. RCM also stimulated, but to a lesser extent, the histamine release from rat peritoneal cells. The RCM-induced histamine release from both types of cells was inhibited by dibutyl cyclic AMP or combined treatment with forskolin and 3-isobutyl-1-methylxanthine. Corresponding to these results, RCM markedly reduced the cellular cyclic AMP content. On the other hand, the removal of intracellular but not the extracellular Ca2+ attenuated the RCM-induced mast cell histamine release. From these findings, it is suggested that the decrease in cellular cyclic AMP content and an increase in intracellular Ca2+ contribute at least in part to the RCM-induced mast cell histamine release.

The increased histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by specific IgE

BACKGROUND

The release of histamine by iodinated contrast media (ICM) is higher in coronary artery disease patients than in noncoronary patients during coronary angiogram.

METHODS

Eighty-eight patients who underwent a coronary angiography were classified either as having coronary artery disease or as noncoronary patients. Histamine concentration was higher than the 6.8 nM upper limit in 7 cases (group 1), of whom six were coronary artery disease patients. We compared the IgE and complement fractions in plasma of these patients to two control groups with normal histamine blood level, one (group 2) with and the other (group 3) without coronary artery disease.

RESULTS

No difference of total IgE and C(3c) and C(4) complement fractions was found among the three groups. Anti-ioxaglate IgE-RIA was positive in only one patient from group 1. The affinity of drug-IgE binding in the serum of this patient was very low (Kd: 18.7 mM). The level of anti-ICM IgE detected by ioxitalamate- and iomeprol-Sepharose RIA was significantly higher in groups 2 and 3 than in group 1.

CONCLUSIONS

The higher histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by IgE or complement activation. Further studies are needed to investigate the implication of histamine release factors.