Intolerance to dietary biogenic amines: a review

Migraine: where and how does the pain originate?

Migraine is a complex neurological disease with a genetic background. Headache is the most prominent and clinically important symptom of migraine but its origin is still enigmatic. Numerous clinical, histochemical, electrophysiological, molecular and genetical approaches form a puzzle of findings that slowly takes shape. The generation of primary headaches like migraine pain seems to be the consequence of multiple pathophysiological changes in meningeal tissues, the trigeminal ganglion, trigeminal brainstem nuclei and descending inhibitory systems, based on specific characteristics of the trigeminovascular system. This contribution reviews the current discussion of where and how the migraine pain may originate and outlines the experimental work to answer these questions.

Alcohol and migraine: trigger factor, consumption, mechanisms. A review

This study investigates the importance of alcohol as a migraine trigger factor, the prevalence of alcohol consumers and the mechanism of headache provocation. A MEDLINE search from 1988 to October 2007 was performed for "headache and alcohol", "headache and wine", "migraine and alcohol" and "migraine and wine". In retrospective studies, about one-third of the migraine patients reported alcohol as a migraine trigger, at least occasionally, but only 10% of the migraine patients reported alcohol as a migraine trigger frequently. Regional differences were reported, perhaps depending in part on alcohol habits. No differences were found between migraine and tension headache and different genders. However, prospective studies limit considerably the importance of alcohol as a trigger. Recent studies show that migraine patients consume less alcohol than controls. Red wine was reported to be the principal trigger of migraine, but other studies show that white wine or other drinks are more involved. Then, the discussion based on the different composition of the various alcoholic beverages, in order to discover the content of alcoholic drinks responsible for migraine attack, reflects this uncertainty. Biogenic amines, sulphites, flavonoid phenols, 5-hydroxytryptamine mechanisms and vasodilating effects are discussed. The fact that few headache patients cannot tolerate some alcoholic drinks does not justify the consideration that alcohol is a major trigger and the suggestion of abstinence. In fact, low doses of alcohol can have a beneficial effect on patients such as migraineurs, who were reported to have an increased risk of cardiovascular disease.

Trace amine-associated receptor 1-Family archetype or iconoclast?

Interest has recently been rekindled in receptors that are activated by low molecular weight, noncatecholic, biogenic amines that are typically found as trace constituents of various vertebrate and invertebrate tissues and fluids. The timing of this resurgent focus on receptors activated by the "trace amines" (TA) beta-phenylethylamine (PEA), tyramine (TYR), octopamine (OCT), synephrine (SYN), and tryptamine (TRYP) is the direct result of 2 publications that appeared in 2001 describing the cloning of a novel G protein-coupled receptor (GPCR) referred to by their discoverers Borowsky et al. as TA1 and Bunzow et al. as TA receptor 1 (TAR1). When heterologously expressed in Xenopus laevis oocytes and various eukaryotic cell lines, recombinant rodent and human TAR dose-dependently couple to the stimulation of adenosine 3',5'-monophosphate (cAMP) production. Structure-activity profiling based on this functional response has revealed that in addition to the TA, other biologically active compounds containing a 2-carbon aliphatic side chain linking an amino group to at least 1 benzene ring are potent and efficacious TA receptor agonists with amphetamine (AMPH), methamphetamine, 3-iodothyronamine, thyronamine, and dopamine (DA) among the most notable. Almost 100 years after the search for TAR began, numerous TA1/TAR1-related sequences, now called TA-associated receptors (TAAR), have been identified in the genome of every species of vertebrate examined to date. Consequently, even though heterologously expressed TAAR1 fits the pharmacological criteria established for a bona fide TAR, a major challenge for those working in the field is to discern the in vivo pharmacology and physiology of each purported member of this extended family of GPCR. Only then will it be possible to establish whether TAAR1 is the family archetype or an iconoclast.

Occurrence of biogenic amines and polyamines in spinach and changes during storage under refrigeration

Biogenic amines and polyamines were studied in 18 market samples of spinach. Histamine and spermidine were detected in relatively high amounts in all samples within the ranges of 9.5-69.7 and 15.6-53.0 mg/kg, respectively. Other biologically active amines were either detected at low levels or not found at all. Changes in amine content during storage at 6 degrees C were studied. The content of most of the amines remained constant during storage, with the exception of spermidine and histamine. Spermidine showed a clear decreasing trend, whereas histamine significantly increased in all trials, but decreased at the end of the storage in two of the trials. Trials showing a decrease in histamine content also showed the highest spermidine decrease and recorded the highest pH values. Microbial loads throughout storage were also followed, with Pseudomonadaceae and Enterobacteriaceae being the predominant bacterial groups. Trials with higher microbial loads in initial samples also showed the highest histamine content in these samples. Potential explanations for both the formation and the degradation of histamine during storage are discussed.

Amine oxidases and monooxygenases in the in vivo metabolism of xenobiotic amines in humans: has the involvement of amine oxidases been neglected?

In this review, the major enzyme systems involved in vivo in the oxidative metabolism of xenobiotic amines in humans are discussed, i.e. the monooxygenases [cytochrome P450 system (CYPs) and flavin-containing monooxygenases (FMOs)] and the amine oxidases (AOs). Concerning the metabolism of xenobiotic amines (drugs in particular) by monoamine oxidases (MAOs), this aspect has been largely neglected in the past. An exception is the extensive investigation carried out on the inhibition of the metabolism of tyramine, when tyramine-containing food is ingested by subjects taking inhibitors of MAO A or of both MAO A and B. Moreover, investigations in humans on the metabolism of drug amines on the market by AOs, such as semicarbazide-sensitive amine oxidases (SSAOs) and polyamine oxidases (PAOs), are practically nonexistent, with the exception of amlodipine. In contrast to MAOs, monooxygenases (CYP isoenzymes more than FMOs) have been extensively investigated concerning their involvement in the metabolism of xenobiotics. It is possible that the contribution of AOs to the overall metabolism of xenobiotic amines in humans is underestimated or erroneously estimated, as most investigations of drug metabolism are performed using in vitro test systems optimized for CYP activity, such as liver microsomes, and most investigations of drug metabolism in vivo in humans carry out only the identification of the final, stable metabolites. However, for some drugs on the market, the involvement of MAOs in their in vivo metabolism in humans has been demonstrated recently, among these drugs citalopram, sertraline and the triptans are examples that can be mentioned.

Histamine in food: is there anything to worry about?

Biogenic mono-, di- and poly-amines are widely distributed among living organisms. The amines fulfil many important functions in the human body both in the periphery and brain. Some authors suggest that foods rich in biogenic amines, especially histamine, present high health hazards for consumers. However, this is conditional on a range of other factors. The alimentary tract is well equipped with enzymes that inactivate amines and the blood-brain barrier prevents them entering the brain from the circulation. Oxidative deamination, methylation, acetylation and transglutamylation are the degradation pathways which operate efficiently in the stomach, intestines and liver. Particularly important is oxidative deamination. Food histamine poisoning or cheese reaction, manifested itself in patients treated with drugs that inhibit amine oxidases or in patients showing an enterocytic diamine oxidase deficit. It is rather food allergy, which should worry us more, as endogenous histamine release from mast cells is more dangerous. Preventive measures should be undertaken against increases in food allergies.

Histamine and histamine intolerance

Histamine intolerance results from a disequilibrium of accumulated histamine and the capacity for histamine degradation. Histamine is a biogenic amine that occurs to various degrees in many foods. In healthy persons, dietary histamine can be rapidly detoxified by amine oxidases, whereas persons with low amine oxidase activity are at risk of histamine toxicity. Diamine oxidase (DAO) is the main enzyme for the metabolism of ingested histamine. It has been proposed that DAO, when functioning as a secretory protein, may be responsible for scavenging extracellular histamine after mediator release. Conversely, histamine N-methyltransferase, the other important enzyme inactivating histamine, is a cytosolic protein that can convert histamine only in the intracellular space of cells. An impaired histamine degradation based on reduced DAO activity and the resulting histamine excess may cause numerous symptoms mimicking an allergic reaction. The ingestion of histamine-rich food or of alcohol or drugs that release histamine or block DAO may provoke diarrhea, headache, rhinoconjunctival symptoms, asthma, hypotension, arrhythmia, urticaria, pruritus, flushing, and other conditions in patients with histamine intolerance. Symptoms can be reduced by a histamine-free diet or be eliminated by antihistamines. However, because of the multifaceted nature of the symptoms, the existence of histamine intolerance has been underestimated, and further studies based on double-blind, placebo-controlled provocations are needed. In patients in whom the abovementioned symptoms are triggered by the corresponding substances and who have a negative diagnosis of allergy or internal disorders, histamine intolerance should be considered as an underlying pathomechanism.

Food allergies

Food incompatibilities affect approximately 20% of the general population in Western countries. In about one quarter of the affected children and one tenth of affected adults, the incompatibility is based on an allergy, that is, on an immunologically generated incompatibility reaction. Gastrointestinal symptoms occur in a third of these cases. Food allergies are caused by IgE-dependent orIgE-independent immunologic reactions, which lead to an inflammatory reaction, in which mast cells, eosinophilic granulocytes, and other cells are involved. Both genetic and environmental causes are under consideration. New findings concerning the interaction between the innate immune system and intestinal microflora have generated innovative therapeutic concepts, including the use of probiotics to prevent food allergies. The development of recombinant allergens and varieties of allergens will improve diagnostic possibilities and bring new therapeutic options, such as hyposensitization and induction of immunologic tolerance. Food intolerances (non-immunologic food incompatibilities often caused by specific enzyme deficiencies) must be diagnostically differentiated from food allergies.

[Alimentary trigger factors that provoke migraine and tension-type headache]

Based on a review of the literature the authors discuss the role of nutrition in the precipitation of migraine and tension-type headache (TTH). The available information relies largely on the subjective assessment of the patients. Controlled trials suggest that alcohol and caffeine withdrawal are the most important nutritional precipitating factors of migraine and TTH. In addition, there is some evidence that missing meals is also an important factor. Dehydration seems to deserve more attention. A selective sensitivity to red wine has been shown in some patients, the importance of chocolate has been doubted seriously, and scientific evidence for cheese as a precipitating factor is lacking. Despite a series of experimental studies demonstrating that NO donors such as nitroglycerin and parenteral histamine cause headache the role of histamine, nitrates, and nitrites in food remains unclear. Similarly, other biogenic amines and aspartame have not been proven to precipitate headache. Sodium glutamate causes adverse reactions including headache probably at large doses ingested on an empty stomach. Therefore, patients should be advised that food plays a limited role as a precipitating factor of migraine and TTH. Subjective sensitivity to certain foods should be examined critically, and proven precipitating factors should be avoided. General dietary restrictions have not been proven to be useful.

Aktuelle Positionsbestimmung zur Bedeutung von Nahrungsmittelallergien und -unverträglichkeiten bei der Urtikaria

Foods are usually the first suspect as the cause of urticaria. However, a causal relationship is found only in special subtypes of urticaria. IgE-mediated food allergy should be clearly separated from non-allergic hypersensitivity (pseudoallergic reactions). The former may play a role in acute urticaria, particularly in patients with atopic dermatitis. The responsible food proteins vary with age. IgE-mediated sensitization can apply to food-dependent exercise-induced urticaria/anaphylaxis but more often the combination of food intake (irrespective of which type) plus exercise results in symptoms. In chronic urticaria, IgE-mediated sensitization to food is normally irrelevant while pseudoallergic reactions to food additives and perhaps also to biogenic amines may be involved. Another urticaria subtype that may be caused by food is contact urticaria which is mostly found in the context of occupational food handling. Very rarely anisakiasis and nickel may cause food-induced urticaria. Aspirin is able not only to exacerbate and aggravate urticaria but can also enhance food-dependent urticaria.