Tuesday, September 6, 2016

Draft of histamine and neutrophils summary

 2011 Jan;50(1):46-53. doi: 10.1111/j.1600-079X.2010.00808.x. Epub 2010 Oct 22.

Oral melatonin attenuates lung inflammation and airway hyperreactivity induced by inhalation of aerosolized pancreatic fluid in rats.

Chen CF1, Wang D, Reiter RJ, Yeh DY.

Abstract

Melatonin is a free radical scavenger with potent antioxidant properties and immunomodulatory effects. The purpose of this study was to determine the effects of orally administered melatonin in a pancreatic fluid (PF)-induced lung inflammation and airway hyperreactivity model. Aerosolized PF was introduced into airways to induce inflammation in rats. Animals were randomized into three experimental groups: sham treated; PF treated (200 μL/kg); and PF with melatonin (10 mg/kg) pretreatment. Airway reactivity to methacholine, airflow and airway resistance, bronchoalveolar lavage (BAL) cellular differential, the tumor necrosis factor α (TNFα) level, lavage nitric oxide, hydroxyl radical, and lactic dehydrogenase (LDH) were compared among groups. mRNA expressions of inducible nitric oxide synthase (iNOS) and TNFα in lung tissues were determined by real-time polymerase chain reaction. Protein expressions of iNOS and nitrotyrosine and lung tissue myeloperoxidase (MPO) activity were determined using an ELISA assay. Oral melatonin treatment indicated anti-inflammatory efficacy as evidenced by decreased methacholine sensitivity by 24% and airway obstruction by 28%, reduction in BAL eosinophil (P < 0.01) and neutrophil counts (P < 0.05), LDH (P < 0.05), and TNFα concentrations (P < 0.05) when compared to levels in sham-treated rats. Melatonin-treated animals also had reduced nitric oxide and hydroxyl radical concentrations (P < 0.05) in lavage fluid. Oral melatonin significantly reduced mRNA and protein expression of iNOS (P < 0.05 and P < 0.01, respectively), TNFα (P < 0.05), nitrotyrosine (P < 0.05), and MPO activity (P < 0.05) in lung tissues when compared with the sham-treated animals. These results suggest that oral treatment with melatonin had a beneficial effect on PF-induced obstructive ventilatory insufficiency by attenuating nitrosative and oxidative stress.

https://www.ncbi.nlm.nih.gov/pubmed/20964706
Abstract

Compounds known to be histaminane inhibitors in vitro were studied for their ability to potentiate certain pharmacological effects of histamine. If histaminase plays a limiting role in the biological responses to histamine, histaminase inhibitors could serve as pharmacological tools in attempts to elucidate the problem of the possible physiological role of this naturally occurring and biologically highly active amine. The available information on histamine metabolism, histaminase (diamine oxidase), and histaminase inhibitors, was reviewed. The latter may be grouped into: 1) carbonyl reagents (semi-carbazides, hydroxylamines, hydrazines), and 2) substituted or unsubstituted diamines and guanidines. Recent evidence (Schayer et al. 1952, 1953) shows that aminoguanidine and other histaminase inhibitors block the major catabolic pathway of histamine in rats and, to a certain extent, in guinea pigs. Iproniazid (a hydrazine), a potent inhibitor of amine oxidase, blocks the main catabolic pathway of histamine in mice and cats. These two metabolic pathways for histamine catabolism are distinct and apparently related to different enzyme systems. In very recent reports, histaminase inhibitors are said to act as specific potentiators of histamine in the response of highly sensitive smooth muscle preparations (Arunlakshana et al. 1954; Lindel & Westling, 1954; D.J. Smith, 1953). The reported degree of potentiation is small, but it is not clear whether this is due to the same original high sensitivity of the tissue, wich may act as a limiting factor. The published results do not establish that the reported effect is related to inhibition of histaminase, since the possibility is not excluded that the compounds may act as sensitizers of histamine receptors on smooth muscle for which they appear to have some affinity (Ariens, 1954). [TRUNCATED]
https://open.bu.edu/handle/2144/13000

 1989 Jan;83(1):110-5.

Gustatory rhinitis: a syndrome of food-induced rhinorrhea.

Raphael G1, Raphael MH, Kaliner M.

Abstract

The consumption of certain foods causes watery rhinorrhea (gustatory rhinitis) in many individuals. To examine the underlying mechanisms responsible for this common phenomenon, 12 subjects ingested control foods and positive foods (foods that cause rhinorrhea). Nasal lavages performed 10 minutes after each food challenge were analyzed for albumin and total protein. Positive food challenge, but not control food challenge, induced rhinorrhea in all subjects. Positive food challenge increased albumin (7.8 +/- 1.9 to 24.5 +/- 7.6 mg/L; p less than 0.025) and total protein (79 +/- 9 to 258 +/- 41 mg/L; p less than 0.001) without altering the ratio of albumin to total protein (albumin percent). Nasal pretreatment with atropine clinically blocked the positive food-induced rhinorrhea and significantly inhibited secretion of both albumin and total protein, again without affecting the albumin percent. Thus, gustatory rhinitis is produced by spicy foods that stimulate atropine-inhibitable muscarinic receptors (probably on submucosal glands), and the syndrome can be treated prophylactically by use of topical atropine.
https://www.ncbi.nlm.nih.gov/pubmed/2643657

Inactivation of beef plasma amine oxidase by sulfide

Article in Journal of Biological Chemistry 259(5):2923-6 · April 1984 with 5 Reads
Source: PubMed

Abstract
Sulfide irreversibly inactivates beef plasma amine oxidase in a time-dependent reaction. Mercaptoacetic acid and 2-mercaptoethanol do not inactivate the enzyme. The sulfide complex displayed an intense absorption band at 360 nm (epsilon = 6000 M-1 cm-1, per mol of copper) that is assigned as sigma S leads to Cu(II) ligand to metal charge-transfer transition. However, this band slowly decreased in intensity; the final spectrum resembles the spectrum of the dithionite-reduced enzyme. Bleaching at approximately 450-500 nm specifically indicates that the organic cofactor is reduced. EPR parameters for the sulfide complex differ significantly from those observed for the native amine oxidase. Superhyperfine structure, attributable to coordinated nitrogens, is clearly evident. Time-dependent reduction of Cu(II) that parallels the kinetics and absorbance changes was also observed by EPR. The amine oxidaseazide complex was inactivated by sulfide at a considerably slower rate than the resting enzyme. Since azide is known to coordinate to Cu(II) in beef plasma amine oxidase, the data strongly suggest that enzyme-bound copper is the site of action for inhibition by sulfide.
https://www.researchgate.net/publication/16873772_Inactivation_of_beef_plasma_amine_oxidase_by_sulfide

Amine oxidase (copper-containing) (AOC) (EC 1.4.3.21 and EC 1.4.3.22; formerly EC 1.4.3.6) is a family of amine oxidase enzymeswhich includes both primary-amine oxidase and diamine oxidase; these enzymes catalyze the oxidation of a wide range of biogenic amines including many neurotransmitters, histamine and xenobiotic amines. They act as a disulphide-linked homodimer. They catalyse the oxidation of primary amines to aldehydes, with the subsequent release of ammonia and hydrogen peroxide, which requires one copper ion per subunit and topaquinone as cofactor:[2]
RCH2NH2 + H2O + O2  RCHO + NH3 + H2O2
The 3 substrates of this enzyme are primary amines (RCH2NH2), H2O, and O2, whereas its 3 products are RCHO, NH3, and H2O2.
Copper-containing amine oxidases are found in bacteria, fungi, plants and animals. In prokaryotes, the enzyme enables various amine substrates to be used as sources of carbon and nitrogen.[3][4]
This enzyme belongs to oxidoreductases, specifically those acting on the CH-NH2 group of donors with oxygen as acceptor. The systematic name of this enzyme class is amine:oxygen oxidoreductase (deaminating) (copper-containing). This enzyme participates in 8 metabolic pathways: urea cycle and metabolism of amino groups, glycine, serine and threonine metabolism, histidine metabolism, tyrosine metabolism,phenylalanine metabolism, tryptophan metabolism, beta-alanine metabolism, and alkaloid biosynthesis ii. It has 2 cofactors: copper, and PQQ.
https://en.wikipedia.org/wiki/Amine_oxidase_(copper-containing)
 1989 Apr;27(1-2):212-4.

Food-induced histaminosis under diamine oxidase (DAO) blockade in pigs: further evidence of the key role of elevated plasma histamine levels as demonstrated by successful prophylaxis with antihistamines.

Sattler J1, Lorenz W, Kubo K, Schmal A, Sauer S, Lüben L.


Abstract

Using a recently established porcine model, it was clearly shown that oral histamine administration is extremely dangerous in the presence of diamine oxidase (DAO) blockade. Due to the severity of the symptoms (20% death) and the clinical relevance, further interest has been focussed on strategies to prevent or alleviate food induced histaminosis. In a randomized controlled trial, 10 pigs under DAO blockade were challenged with oral histamine (60 mg). Half of these animals received a prophylactic premedication with a combination of H1- and H2-receptor antagonists. As expected, all animals developed a massive increase in plasma histamine levels, with significantly higher values in the control group (median: 123 ng/ml) compared to the antihistamine group (median: 32 ng/ml). In contrast, clinical symptoms were only observed in the control group. The maximum fall in mean arterial pressure (hypotension) was 60 mmHg (median for control group) but only 15 mmHg (median) under antihistamine pretreatment. These results firstly provide further evidence for the causal role of histamine in the new disease concept and secondly enable us to investigate appropriate therapeutic measures for patients at risk.
https://www.ncbi.nlm.nih.gov/pubmed/2568741?dopt=Abstract

Histamine and food

Histamine and other biogenic amines are present to various degrees in many foods, and their presence increases with maturation (1, 72). The formation of biogenic amines in food requires the availability of free amino acids, the presence of decarboxylase-positive microorganisms, and conditions allowing bacterial growth and decarboxylase activity. Free amino acids either occur as such in foods or may be liberated by proteolysis during processing or storage (73). Numerous bacterias and some yeast display high HDC activity and thus have the capacity to form histamine. Histidine is generated from autolytic or bacterial processes (74). Therefore, high concentrations of histamine are found mainly in products of microbial fermentation, such as aged cheese (75), sauerkraut, wine (76), and processed meat (77, 78) (Table 3⇓) or in microbially spoiled food. Thus, histamine, tyramine, putrescine, and cadaverine serve as indicators of hygienic food quality (73). Tyramine and putrescine also may lead to intolerance reactions in combination with histamine. Possible explanations may be the inhibition of DAO by other amines (43) or the promotion of histamine liberation from the mucosa by putrescine (34).
View this table:
TABLE 3
Foods rich in histamine1
Intolerance of tyramine that has vasoconstrictive properties that lead to hypertensive crisis and headache has been known mostly in patients taking monoamine oxidase (MAO)–inhibiting drugs. Orally administered tyramine in doses of 200 to 800 mg has been shown to increase systolic blood pressure by 30 mm Hg in otherwise unmedicated subjects. Conversely, in patients taking MAO-inhibiting drugs, the pressor sensitivity was 7- to 56-fold that in patients not taking MAO-inhibiting drugs (79). Eight DBPC studies have investigated the effect of tyramine on migraine. Two studies showed positive results in migraine patients who were sensitive to foods that are high in tyramine (n = 45) (19) or who had wine-provoked migraine (n = 19) (80); 6 studies showed negative results with 97 (81), 80 (82), 25 (83), and 65 (84) patients. The 2 positive studies and 2 of the negative studies were regarded as inconclusive (19) because of a lack of randomization (79), questionable blinding (80), or inappropriate selection of migraine patients without a history of suspected tyramine intolerance (81, 82). Conversely, in 2 conclusive studies of migraine patients with a positive or negative dietary history, 125 mg oral tyramine did not precipitate more headaches than did placebo.
In addition to histamine-rich food, many foods such as citrus foods are considered to have the capacity to release histamine directly from tissue mast cells, even if they themselves contain only small amounts of histamine (Table 4⇓). In vitro studies of persons with a history of pseudoallergic reactions to food have shown a fragility of duodenal mast cells with massive degranulation in the presence of histamine-releasing substances that is significantly greater than that shown by control subjects (85). However, clinical studies using oral challenge tests to support the hypothesis for the histamine-releasing capacity of foods are required (22).
View this table:
TABLE 4
Foods with suggested histamine-releasing capacities1
Alcohol, especially red wine, is rich in histamine and is a potent inhibitor of DAO (9, 86). The relation between the ingestion of wine, an increase in plasma histamine, and the occurrence of sneezing, flushing, headache, asthma attacks, and other anaphylactoid reactions and a reduction of symptoms by antihistamines has been shown in various studies (7, 8, 14, 65, 87, 88). However, among the multitude of substances contained in wine, other biogenic amines such as tyramine (80) and sulfites (89) have been supposed to contribute to symptoms summarized as “wine intolerance” or “red wine asthma” (19, 89, 90). In DBPC wine tests with healthy persons (91) and in patients with chronic urticaria and wine intolerance (92), the histamine content did not influence wine tolerance. In the latter group, an increase in plasma histamine could be shown, paradoxically, after ingestion of the histamine-poor wine. In these patients, the ethanol metabolite acetaldehyde has been discussed as a histamine-releasing substance (92). However, the high percentage of responses to the placebo (87%) could be responsible for the absence of an effect in this study (19). Another randomized DBPC oral wine challenge in patients with a history of red wine–provoked asthma (n = 18) found no relation between wine tolerance and the wine's content of histamine or other amines but did find a greater bronchoconstrictive response to wine with a high sulfite content (89). Sulfiting agents are widely used as antioxidants and preservatives in foods, beverages, and pharmaceuticals. Adverse reactions with a presumed relation to sulfites include anaphylactic shock, bronchospasm, urticaria, angioedema, nausea, abdominal pain, diarrhea, stroke, and death (93). Sulfite hypersensitivity has been reported mainly in patients with chronic asthma; the estimated prevalence is 5–10% in all patients (94). Asthmatic reactions have been attributed to reflex activation of the parasympathetic system by the irritating effect of sulfites, possibly enhanced by a deficiency of sulfite oxidase. Besides this pseudoallergic mechanism, in at least some cases of sulfite hypersensitity, an immunoglobulin E (IgE)–mediated immediate-type allergic reaction must be considered (95). Sulfites may be contained in wine, but they are also contained in foods that are poor in histamine, such as fruit juice, frozen vegetables, and lettuce. Thus, in patients reporting intolerance to wine, a careful history of reactions to other foods rich in histamine or sulfites should be taken. In patients who are suspected of having sulfite intolerance, skin testing and a DBPC challenge with capsules containing increasing doses of bisulfite or placebo should be performed.
http://ajcn.nutrition.org/content/85/5/1185.full

 2016 May 1;310(9):L860-7. doi: 10.1152/ajplung.00015.2016. Epub 2016 Mar 11.

Reduced mucociliary clearance in old mice is associated with a decrease in Muc5b mucin.

Grubb BR1, Livraghi-Butrico A1, Rogers TD1, Yin W1, Button B1, Ostrowski LE2.


Abstract

Respiratory infections are a major cause of morbidity and mortality in the elderly. Previous reports have suggested that mucociliary clearance (MCC) is impaired in older individuals, but the cause is unclear. To unravel the mechanisms responsible for the age-associated decline in MCC, we investigated the MCC system in young (3 mo) and old (2 yr) C57BL/6 mice. We found that old mice had significantly reduced MCC function in both the upper and lower airways compared with young mice. Measurement of bioelectric properties of isolated tracheal and bronchial tissue revealed a significant decrease in Cl(-) secretion, suggesting that the older mice may have a reduced ability to maintain a sufficiently hydrated airway surface for efficient MCC. Ciliary beat frequency was also observed to be reduced in the older animals; however, this reduction was small relative to the reduction in MCC. Interestingly, the level of the major secreted mucin, Muc5b, was found to be reduced in both bronchioalveolar lavage and isolated tracheal tissue. Our previous studies of Muc5b(-/-) mice have demonstrated that Muc5b is essential for normal MCC in the mouse. Furthermore, examination of Muc5b(+/-) and wild-type animals revealed that heterozygous animals, which secrete ∼50% of the wild-type level of Muc5b, also demonstrate a markedly reduced level of MCC, confirming the importance of Muc5b levels to MCC. These results demonstrate that aged mice exhibit a decrease in MCC and suggest that a reduced level of secretion of both Cl(-) and Muc5b may be responsible.
https://www.ncbi.nlm.nih.gov/pubmed/26968767

 2016 Jul 20. doi: 10.1038/mi.2016.63. [Epub ahead of print]

Contribution of mucus concentration and secreted mucins Muc5ac and Muc5b to the pathogenesis of muco-obstructive lung disease.

Livraghi-Butrico A1, Grubb BR1, Wilkinson KJ1, Volmer AS1, Burns KA1, Evans CM2, O'Neal WK1, Boucher RC1.

Abstract

Airway diseases, including cigarette smoke-induced chronic bronchitis, cystic fibrosis, and primary ciliary dyskinesia are associated with decreased mucociliary clearance (MCC). However, it is not known whether a simple reduction in MCC or concentration-dependent mucus adhesion to airway surfaces dominates disease pathogenesis or whether decreasing the concentration of secreted mucins may be therapeutic. To address these questions, Scnn1b-Tg mice, which exhibit airway mucus dehydration/adhesion, were compared and crossed with Muc5b- and Muc5ac-deficient mice. Absence of Muc5b caused a 90% reduction in MCC, whereas Scnn1b-Tg mice exhibited an ∼50% reduction. However, the degree of MCC reduction did not correlate with bronchitic airway pathology, which was observed only in Scnn1b-Tg mice. Ablation of Muc5b significantly reduced the extent of mucus plugging in Scnn1b-Tg mice. However, complete absence of Muc5b in Scnn1b-Tg mice was associated with increased airway inflammation, suggesting that Muc5b is required to maintain immune homeostasis. Loss of Muc5ac had few phenotypic consequences in Scnn1b-Tg mice. These data suggest that: (i) mucus hyperconcentration dominates over MCC reduction alone to produce bronchitic airway pathology; (ii) Muc5b is the dominant contributor to the Scnn1b-Tg phenotype; and (iii) therapies that limit mucin secretion may reduce plugging, but complete Muc5b removal from airway surfaces may be detrimental.Mucosal Immunology advance online publication, 20 July 2016; doi:10.1038/mi.2016.63.
https://www.ncbi.nlm.nih.gov/pubmed/27435107
 2013 Jul;27(7):2902-10. doi: 10.1096/fj.12-223867. Epub 2013 Apr 9.

Histamine production by human neutrophils.

Alcañiz L1, Vega A, Chacón P, El Bekay R, Ventura I, Aroca R, Blanca M, Bergstralh DT, Monteseirin J.


Abstract

Histamine is an important mediator in the development of allergic reactions. Only a small subset of human cell types is able to produce histamine. No previous studies have shown that human neutrophils are among them. The present work was undertaken to analyze whether human neutrophils produce histamine, and to determine what agonists are involved in histamine production by human neutrophils. The expression of histidine decarboxylase in human neutrophils was established by quantitative PCR, Western blotting, and flow cytometry analysis. The activity of the enzyme was determined by ELISA, which measured histamine in the culture supernatant of neutrophils stimulated with a set of classical agonists. Human neutrophils are bona fide histamine-producing cells. Neutrophils store ∼0.29 pg/cell and release ∼50% of the histamine content in an antigen-dependent manner and on stimulation with other neutrophil agonists. Basal expression of histidine decarboxylase, the rate-limiting enzyme in histamine production, is higher in neutrophils from patients with allergies than from healthy donors. Our results cannot be ascribed to cell contamination for several reasons. LPS failed to induce histamine release by basophils, whereas it induced histamine release by neutrophils; and we did not detect basophils, monocytes, or lymphocytes in our neutrophil preparations. Eosinophils, albeit detected, were only 0.001-0.004% of the final cell population, and they did not store or release histamine on antigen or LPS stimulation. Antigens to which patients with allergies were sensitized stimulated release of histamine from neutrophils. These observations represent a novel view of neutrophils as possible source of histamine in the allergic diseases.
https://www.ncbi.nlm.nih.gov/pubmed/23572231

 2007 May;151(2):195-205. Epub 2007 Mar 20.

Melatonin inhibits nitric oxide production by microvascular endothelial cells in vivo and in vitro.

Silva CL1, Tamura EK, Macedo SM, Cecon E, Bueno-Alves L, Farsky SH, Ferreira ZS, Markus RP.

Abstract

BACKGROUND AND PURPOSE:

We have previously shown that melatonin inhibits bradykinin-induced NO production by endothelial cells in vitro. The purpose of this investigation was to extend this observation to an in vivo condition and to explore the mechanism of action of melatonin.

EXPERIMENTAL APPROACH:

RT-PCR assays were performed with rat cultured endothelial cells. The putative effect of melatonin upon arteriolar tone was investigated by intravital microscopy while NO production by endothelial cells in vitro was assayed by fluorimetry, and intracellular Ca(2+) measurements were assayed by confocal microscopy.

KEY RESULTS:

No expression of the mRNA for the melatonin synthesizing enzymes, arylalkylamine N-acetyltransferase and hydroxyindole-O-methyltransferase, or for the melatonin MT(2) receptor was detected in microvascular endothelial cells. Melatonin fully inhibited L-NAME-sensitive bradykinin-induced vasodilation and also inhibited NO production induced by histamine, carbachol and 2-methylthio ATP, but did not inhibit NOproduction induced by ATP or alpha, beta-methylene ATP. None of its inhibitory effects was prevented by the melatonin receptor antagonist, luzindole. In nominally Ca(2+)-free solution, melatonin reduced intracellular Ca(2+) mobilization induced by bradykinin (40%) and 2-methylthio ATP (62%) but not Ca(2+) mobilization induced by ATP.

CONCLUSIONS AND IMPLICATIONS:

We have confirmed that melatonin inhibited NO production both in vivo and in vitro. In addition, themelatonin effect was selective for some G protein-coupled receptors and most probably reflects an inhibition of Ca(2+) mobilization from intracellular stores.
https://www.ncbi.nlm.nih.gov/pubmed/17375079

. 2006 Dec 25; 203(13): 2907–2917.
PMCID: PMC2118183
Article

Neutrophil histamine contributes to inflammation in mycoplasma pneumonia

Abstract

Mycoplasmas cause chronic inflammation and are implicated in asthma. Mast cells defend against mycoplasma infection and worsen allergic inflammation, which is mediated partly by histamine. To address the hypothesis that mycoplasma provokes histamine release, we exposed mice to Mycoplasma pulmonis, comparing responses in wild-type and mast cell–deficient KitW-sh/KitW-sh (W-sh) mice. Low histamine levels in uninfected W-sh mice confirmed the conventional wisdom that mast cells are principal sources of airway and serum histamine. Although mycoplasma did not release histamine acutely in wild-type airways, levels rose up to 50-fold above baseline 1 week after infection in mice heavily burdened with neutrophils. Surprisingly, histamine levels also rose profoundly in infected W-sh lungs, increasing in parallel with neutrophils and declining with neutrophil depletion. Furthermore, neutrophils from infected airway were highly enriched in histamine compared with naive neutrophils. In vitro, mycoplasma directly stimulated histamine production by naive neutrophils and strongly upregulated mRNA encoding histidine decarboxylase, the rate-limiting enzyme in histamine synthesis. In vivo, treatment with antihistamines pyrilamine or cimetidine decreased lung weight and severity of pneumonia and tracheobronchitis in infectedW-sh mice. These findings suggest that neutrophils, provoked by mycoplasma, greatly expand their capacity to synthesize histamine, thereby contributing to lung and airway inflammation.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2118183/


Histamine and histamine intolerance1,2,3

  1. Natalija Novak

Abstract

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.
http://ajcn.nutrition.org/content/85/5/1185.full

 2005 Nov;31(4):360-4.

Delayed neutrophil apoptosis attenuated by melatonin in human acute pancreatitis.

Chen HM1, Hsu JT, Chen JC, Ng CJ, Chiu DF, Chen MF.

Abstract

OBJECTIVES:

This study evaluated the expression of neutrophil apoptosis and the effects of melatonin at different concentrations on delayedneutrophil apoptosis in different severities of acute pancreatitis in patients.

METHODS:

The study population was comprised of 10 patients with severe acute pancreatitis (SAP) and 10 with mild acute pancreatitis (MAP). A total of 10 mL of blood was drawn 24 hours after the onset of the clinical disease for isolation and incubation of the human neutrophils with 4 different concentrations of melatonin. Neutrophil apoptosis activity, CD18 expression, and respiratory burst activity were assessed with flow cytometry 12 hours after incubation. Another group of neutrophils from a healthy control group was used (n = 6) for comparison.

RESULTS:

Neutrophil apoptosis in patients with SAP is delayed compared with that of patients with MAP. Neutrophils from patients with SAP or MAP are functionally activated. Melatonin at concentrations of 10(-8), 10(-7), or 10(-6) M reverses the delayed process and enhances apoptosisactivity in neutrophils in patients with MAP. Melatonin at concentrations of 10(-7) and 10(-6) M reverses the delayed process and increasesapoptosis activity in neutrophils in patients with SAP. Neutrophils from patients with SAP and MAP showed significantly increased CD18 expression and respiratory burst activity. Melatonin at concentrations of 10(-7) or 10(-6) M reverses CD18 expression and respiratory burst activity in neutrophils in patients with SAP.

CONCLUSIONS:

This study highlights the importance of neutrophil apoptosis in patients with SAP and raises the possibility of a therapeutic strategy. Study data show that melatonin promotes neutrophil apoptosis in human acute pancreatitis.
https://www.ncbi.nlm.nih.gov/pubmed/16258371
at 2:30 PM

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