Asociación de polimorfismos de diaminoxidasa e histamina N metiltransferasa con la presencia, discapacidad y severidad de migraña en un grupo de madres mexicanas de niños alérgicos / Association of diamine oxidase and histamine N-methyltransferase polymorphisms with presence of migraine in a group of Mexican mothers of children with allergies

Introducción: Se ha sugerido que una degradación disminuida de histamina puede contribuir en la patogénesis de migraña y alergia. Este trabajo investiga una posible asociación entre 2 polimorfismos de un solo nucleótido (SNP) de 2 enzimas que degradan histamina, C314T para la histamina N-metil-transferasa (HNMT) y C2029G para diaminoxidasa (DAO), con la presencia, discapacidad y severidad de la migraña. Material y métodos: Se reclutó a 162 madres de niños alérgicos (80 con migraña y 82 sin migraña) determinando las variantes alélicas por PRC tiempo real usando un modelo de casos y controles. Mediante regresión logística se determinaron las OR para los genotipos y haplotipos. Resultados: El alelo mutado G para DAO fue significativamente más frecuente en el grupo de mujeres migrañosas que en los controles (OR = 1,6; IC del 95% = 1,1-2,1). No encontramos diferencias significativas para el alelo mutado T de la HNMT. Ambos alelos mutados estuvieron asociados a la discapacidad causada por la migraña. La coexistencia de ambas mutaciones (haplotipos) mostró una fuerte asociación con migraña. Los haplotipos que tenían ambos alelos mutados (ya sea como homocigotos o heterocigotos) estuvieron fuertemente asociados a la discapacidad por migraña grado iv (OR = 45,0, IC del 95% = 5,2-358). Esto sugiere que los alelos mutados T para HNMT y G para DAO pueden interactuar incrementando el riesgo y el impacto de la migraña. Conclusiones: Se sugiere una asociación sinérgica de polimorfismos de HNMT y DAO con migraña el cual debe ser confirmado en futuros estudios. La interpretación debe tomar en cuenta las características étnicas de la población estudiada (AU)

Background: Low histamine metabolism has been suggested to play a role in the pathogenesis of allergy and migraine. We investigated the possible association between 2 single-nucleotide polymorphisms (SNP), C314 T HNMT and C2029G DAO, and the presence and severity of migraine and migraine-related disability. Materials and methods: We studied the frequency of C314 T HNMT and C2029G DAO allelic variants in 162 mothers of children with allergies (80 with migraine and 82 without) using a TaqMan-based qPCR Assay and a case-control model. We conducted a logistic regression analysis to examine the association between migraine and the allelic and haplotype variants. Results: Mutant C2029G DAO SNP was found significantly more frequently in the group of women with migraine than in controls (OR, 1.6; 95% CI, 1.1–2.1). No significant differences were found in frequencies of genotypes or alleles in the case of C314T HNMT SNP. Both mutated alleles were associated with migraine-related disability. Coexistence of alleles for both SNPs (haplotypes) showed a strong association with migraine. Haplotypes containing both mutated alleles (either heterozygous or homozygous) were very strongly associated with MIDAS grade iv migraine (OR, 45.0; 95% CI, 5.2-358). This suggests that mutant alleles of C314 T for HNMT and C2029G for DAO polymorphisms may interact in a way that increases the risk and impact of migraine. Conclusions: We suggest a synergistic association between HNMT and DAO functional polymorphisms and migraine; this hypothesis must be further confirmed by larger studies. However, the characteristics and ethnic differences between analysed populations should be considered when interpreting the results (AU)

Chemopreventive mechanisms of methionine on inhibition of benzo(a)pyrene-DNA adducts formation in human hepatocellular carcinoma HepG2 cells.

This study was designed to investigate the molecular mechanism underlying the chemopreventive effects of methionine on benzo[a]pyrene (B[a]P)-DNA adducts formation in HepG2 cells. Methionine significantly inhibited B[a]P-DNA adduct formation in HepG2 cells. Methionine significantly decreased the cellular uptake of [(3)H] B[a]P, but increased the cellular discharge of [(3)H] B[a]P from HepG2 cells into the media. B[a]P significantly lowered total cellular glutathione (GSH) level, but co-cultured with B[a]P and methionine, gradually attenuated intracellular GSH levels in a concentration-dependent manner, which was markedly higher at 20-500µM methionine. The cellular proteins of treated cells were resolved by 2D-polyacrylamide gel electrophoresis. Proteomic profiles showed that phase II enzymes such as glutathione S-transferase (GST) omega-1, GSTM3, glyoxalase I (GLO1) and superoxide dismutase (SOD) were down-regulated by B[a]P treatment, whereas cathepsin B (CTSB), Rho GDP-dissociation inhibitor alpha (Rho-GDP-DIA), histamine N-methyltransferase (HNMT), spermidine synthase (SRM) and arginase-1 (ARG1) were up-regulated by B[a]P. B[a]P and methionine treatments, GST omega-1, GSTM3, GLO1 and SOD were significantly enhanced compared to B[a]P alone. Similarly, methionine was effective in diminishing the B[a]P-induced up-regulation of CTSB, Rho-GDP-DIA, HNMT, SRM and ARG1. Our data suggests that methionine might exert a chemoprotective effect on B[a]P-DNA adduct formation by attenuating intracellular GSH levels, blocking the uptake of B[a]P into cells, or by altering expression of proteins involved in DNA adduct formation.

Histamine inactivation in the colon of pigs in relationship to abundance of catabolic enzymes.

OBJECTIVE: Catabolism of histamine plays a crucial role in the intestine in preventing intoxication by luminal histamine. Two enzymes are involved, namely histamine N-methyltransferase (HMT) and diamine oxidase (DAO). The purpose of this study was to find a link between histamine catabolism and the activities of HMT and DAO. MATERIAL AND METHODS: Epithelia of porcine proximal colon were mounted in Ussing chambers. After mucosal addition of (3)H-histamine (100 micromol x l(-1)) and (14)C-mannitol, the appearance of non-catabolized histamine, (3)H-histamine label (hist-rad) and (14)C-mannitol label were measured in parallel on the serosal side. Activities of HMT and DAO were determined in the proximal colon and proximal jejunum. RESULTS: Differences between the fluxes of histamine and hist-rad indicated catabolic conversion of 81.4+/-1.6% histamine during epithelial transit. Fluxes of hist-rad and histamine increased linearly with increasing mannitol fluxes but the percentage of catabolized histamine was not related to either mannitol or hist-rad fluxes. However, the percentage of catabolized histamine rose with increasing DAO activity. Given a negative correlation between DAO and HMT activities, the fraction of catabolized histamine decreased with increasing HMT activity. HMT activity was comparable in the colon and jejunum, but DAO activity was approximately nine times higher in the jejunum. CONCLUSIONS: Permeation, but not the relative efficiency of catabolism, of histamine depends on epithelial/paracellular tightness. While previous studies have shown that colonic HMT essentially catabolizes the bulk of histamine during permeation, DAO activity seems to be more variable and limiting for the overall efficiency of the catabolic process.

Rapid and simple determination of histamine-N-methyl transferase activity by high-performance liquid chromatography with UV detection.

A rapid, simple and low-cost assay method of histamine-N-methyltransferase activity was developed. Methylhistamine, which was separated from the enzymatic reaction system on reversed-phase high-performance liquid chromatography using an ion-paired chromatographic technique, was detected spectrophotometrically at 226 nm. The mobile phase used for the separation of methylhistamine was 0.05M NH4H2PO4 (pH 3.0) containing 2 mM of sodium octanesulfonate. The new assay technique could detect methylhistamine as an enzyme activity product of histamine-N-methyltransferase in the brain and kidney of rats. Chloropheniramine maleate, an antihistamine, activated the histamine-N-methyltransferase. Whether neurotransmitter or neuromodulator, the role of histamine in the brain has not yet been made clear. Therefore, the present method could be applicable for the enzymatic investigation of histamine metabolism in central nervous system or inflammatory reactions.

Neuronal and vascular localization of histamine N-methyltransferase in the bovine central nervous system.

Histamine N-methyltransferase (HMT) (EC 2.1.1.8) plays a crucial role in the inactivation of the neurotransmitter histamine in the CNS. However, the localization of HMT remains to be determined. In the present study, we investigated immunohistochemical localization of HMT in the bovine CNS using a polyclonal antibody against bovine HMT. The HMT-like immunoreactivity was observed mainly in neurons. Strongly immunoreactive neurons were present in the oculomotor nucleus and ruber nucleus in the midbrain, the facial nucleus in the pons, the dorsal vagal nucleus and hypoglossal nucleus in the medulla oblongata and in the anterior horn as well as intermediolateral zone of the spinal cord. Intermediately immunoreactive neurons were present in the piriform cortex and the inferior olivary nucleus. The grey matter of the forebrain regions was diffusely and faintly stained. In the cerebellum and the striatum, the nerve fibres in the white matter were positive. The tuberomammillary nucleus, where histaminergic neurons are present, were weakly positive. The other immunoreactive structures in the CNS were blood vessels. Almost all of the blood vessel walls, irrespective of whether they were arterial or venous, were variably stained. The glial fibrillary acidic protein- (GFAP-) immunoreactive astrocytes were not stained. These findings indicated that histamine released from histaminergic nerve terminals or varicose fibres is methylated mainly in postsynaptic or extrasynaptic neurons rather than in astrocytes. The localization of HMT in the blood vessel wall may mean that blood-borne histamine and histamine released from mast cells associated with the blood vessels are catabolized in this structure.

Localization of histamine N-methyltransferase messenger RNA in human nasal mucosa.

BACKGROUND: Histamine is metabolized mainly by histamine N-methyltransferase (HMT) to N tau-methylhistamine in human nasal mucosa. Human HMT cDNA has been cloned and expressed in COS cells. The purpose of this study was to determine the localization of HMT METHODS: The fragment (nucleotide residues 430-1055) of human HMT cDNA was subcloned in a Bluescript vector (Stratagene, La Jolla, Calif.), and HMT sense anti-sense RNA probes were made with T7 and T3 RNA polymerases. In situ hybridization with digoxigenin-labeled RNA probes was performed on surgical specimens of human nasal turbinates. RESULTS: HMT mRNA was localized in cells in the epithelium and submucosa, and densely in endothelial cells of vessels. No HMT mRNA was identified in the submucosal glands. The presence of HMT mRNA was confirmed by Northern blot analysis, and HMT activities were also detected in nasal mucosa. CONCLUSION: Our study indicates that endothelium expresses HMT mRNA, whereas cells in the epithelium and submucosa, which remain unidentified, are an additional source of HMT mRNA.

Histamine N-methyl transferase: inhibition by drugs.

1. Histamine N-methyl transferase activity was measured in samples of human liver, brain, kidney, lung and intestinal mucosa. The mean (+/- s.d.) rate (nmol min-1 mg-1 protein) of histamine N-methylation was 1.78 +/- 0.59 (liver, n = 60), 1.15 +/- 0.38 (renal cortex, n = 8), 0.79 +/- 0.14 (renal medulla, n = 8), 0.35 +/- 0.08 (lung, n = 20), 0.47 +/- 0.18 (human intestine, n = 30) and 0.29 +/- 0.14 (brain, n = 13). 2. Inhibition of histamine N-methyl transferase by 15 drugs was investigated in human liver. The IC50 for the various drugs ranged over three orders of magnitude; chloroquine was the most potent inhibitor. 3. The average IC50 values for chloroquine were 12.6, 22.0, 19.0, 21.6 microM in liver, renal cortex, brain and colon, respectively. These values are lower than the Michaelis-Menten constant for histamine N-methyltransferase in liver (43.8 microM) and kidney (45.5 microM). Chloroquine carried a mixed non-competitive inhibition of hepatic histamine N-methyl transferase. Some side-effects of chloroquine may be explained by inhibition of histamine N-methyl transferase.

High-performance liquid chromatographic determination of histamine N-methyltransferase activity.

A method for the determination of histamine N-methyltransferase (HMT) activity by high-performance liquid chromatography based on post-column derivatization with omicron-phthalaldehyde is described. The determination involves the separation of the substrate, histamine, from its product. N tau-methylhistamine, using a weak cation exchanger, followed by on-line derivatization of these imidazoleamines with omicron-phthalaldehyde and their detection and quantitation with a fluorimetric detector. This assay method is suitable for the measurement of HMT activity during enzyme purification.

Histamine methyltransferase in dispersed cells from rabbit fundic mucosa.

The cellular distribution of histamine N-methyltransferase was studied in rabbit gastric mucosa. The fundic mucosa was dispersed by collagenase treatment in Hanks' or calcium-free medium. In calcium-free medium, the number of dispersed cells/g wet tissue, as well as their viability was increased; histamine N-methyltransferase recovery was up to three-fold larger than in cells prepared in Hanks' medium. Furthermore, the calcium-free medium led to a greater acid secretory response, whereas the cellular pepsinogen content tended to be lower. Histamine N-methyltransferase activity was found in all cell fractions but was higher in the larger cell types. The enzyme activity showed only a partial correlation with either oxyntic or chief cells. These results indicate that the use of calcium-free medium to disperse and isolate rabbit mucosal cells improves cell quality. Histamine N-methyltransferase in the rabbit fundic mucosa, is found in more than one cell type, primarily the oxyntic and chief cells.

Histamine, histidine decarboxylase and histamine-N-methyltransferase in brain areas of spontaneously hypertensive rats.

Histamine levels, histidine decarboxylase and histamine-N-methyltransferase activities were determined in various brain areas of young (9-week old) and adult (18-week old) normotensive rats (WKY) and hypertensive rats (SHR). When compared with WKY, histamine levels were increased in the anterior and posterior hypothalamus of young and adult SHR, as well as in the brainstem of young SHR. Histidine decarboxylase activity was unchanged in the posterior hypothalamus and in the medulla oblongata of young and adult SHR as well as in the anterior hypothalamus of young SHR, but it was slightly decreased in the anterior hypothalamus of adult SHR. Histidine decarboxylase activity was enhanced in the cortex-midbrain of young, as well as adult SHR, histamine-N-methyltransferase in the cortex-midbrain of young SHR. The following differences were found between young and adult rats: histamine levels were elevated in the cortex-midbrain of adult WKY and SHR. In the cortex-midbrain and brainstem of adult WKY and SHR histidine decarboxylase activity was also increased, while histamine-N-methyltransferase activity was elevated in the cortex-midbrain of adult WKY. The findings show changes in histamine levels, histidine decarboxylase and histamine-N-methyltransferase activities in SHR and suggest involvement of histaminergic neurons in hypertension. The activity of histaminergic neurons of adult rats seems to be higher than that of young animals.

Effect of electroconvulsive shock (ECS) treatment on the histaminergic system in rat brain: biochemical and behavioural studies.

The effects of electroconvulsive shock (ECS) on brain histamine (HI) levels, 1-histidine decarboxylase (HD) and HI-methyltransferase (HMT) activities, and H2-receptor--mediated hypothermia were studied in rats. Single (x1) and repeated (x10, once daily) ECS had practically no effect on both HI levels and HMT activities in the rat hypothalamus, cerebral cortex and rest of the brain. ECS x10 significantly increased HI accumulation. ECS x1 (only after 24 h) and ECS x10 resulted in marked elevation of the brain HD activity; the most pronounced effect was observed in the cerebral cortex. Repeated, but not single, ECS reduced the hypothermic action of various centrally given histamine H2-receptor agonists (HI, 4-methylHI, dimaprit and impromidine). It is suggested that prolonged treatment with ECS activates the central histaminergic system in the rat. The histaminergic neurons in the cerebral cortex seem to be especially affected by repeated ECS.

Immunohistochemical demonstration of histamine N-methyltransferase-like structures in rat kidney.

Histamine N-methyltransferase (S-adenosylmethionine: histamine N-methyltransferase, E.C. 2.1.1.8) was purified to homogeneity from rat kidney, and antibody was raised against it in guinea pigs. The antibody immunoprecipitated histamine N-methyltransferase. Immunofluorescent histochemical studies with anti-histamine N-methyltransferase antibody as the first antibody and goat anti-guinea pig IgG conjugated with fluorescein isothiocyanate as the second, showed the presence of immunoreactive structures in the proximal tubules of rat kidney. The brain showed no immunoreaction with the antibody.

Change of hepatic histamine content during hepatic fibrosis.

Hepatic function was studied by measuring the time courses of several variables in blood and liver using a chronic liver-injury model produced by administering CCl4 consecutively for 12 weeks in rats. A marked increase in liver histamine content occurred after 10 weeks of treatment with CCl4. At weeks 10 and 12, liver histamine levels in the CCl4-treated group were 1.95 and 4.61 times higher, respectively, than in the control group. This change in liver histamine content appeared after that in other variables such as glutamic pyruvic transaminase, alkaline phosphatase, and white blood cells, but it corresponded to a change in liver hydroxyproline. Increased mast cells were seen in fibrotic foci around Glisson's sheath by microscopic morphological observation of the liver 12 weeks after treatment with CCl4. The histamine concentration in plasma tended to decrease after CCl4 treatment, and at week 12 the decrease was statistically significant compared with control. The liver activities of histamine-metabolizing enzymes, histamine-N-methyltransferase and histaminase, decreased to 1/3.4 and 1/6.0 times those of the nontreated group, respectively, 12 weeks after treatment with CCl4, whereas blood histaminase increased about 9.2 times. The increase in histamine content in injured liver was presumedly derived from the increase in mast cells in the inflamed area of the liver; also, the deficiency of histamine-metabolizing enzymes in liver might have caused the high histamine content in the liver. On the other hand, the decrease in plasma histamine concentration might have occurred as a consequence of the enzyme leakage from hepatocytes that accompanied the breakdown of hepatocytes by CCl4 and thus, of the histamine metabolism in blood by the leaked enzymes. The same kind of experiment was performed using a dimethylnitrosamine-induced liver injury model in rats. The increase of hydroxyproline in the liver occurred 11 days after that of histamine content in liver. These results suggest the possibility that increased histamine in the liver may participate in the biosynthesis of collagen.

Histamine in the rabbit eye: distribution, synthesis, catabolism, and changes by light stimulation.

Histamine (HI) is present in all studied ocular (retina, choroid, optic nerve) and brain structures of the albino rabbit. HI levels in neural eye elements (retina and optic nerve) are relatively low, i.e. 70-140 ng/g tissue, and comparable with those found in the brain; a typical vascular tissue, i.e. choroid, contained approximately 10 times more HI. Histadine decarboxylase (HD) activity was found only in brain tissue, while histamine-methyltransferase (HMT) activity was present in all the eye and brain structures. Light stimulation produced changes in HI content only in the retina (decrease) and in the optic nerve (increase).

Histamine in the rat brain: effect of acute and chronic treatment with tricyclic antidepressants and H1-antihistaminics.

Prolonged (for two weeks), but not acute, intensive treatment with tricyclic antidepressant drugs (amitriptyline, AMI; doxepine, DOX; imipramine, IMI) and H1-antihistaminics (chloropyramine, CPYR; diphenhydramine, DPHA; promethazine, PMZ; tripelenamine, TPA) decreased histamine (HI) level in rat brain, especially in the cerebral cortex. These drugs did not modify L-histidine decarboxylase activity in any analyzed brain structure, except chronically given AMI and IMI which significantly increased the enzyme activity. None of the tested compounds, administered both acutely or chronically, affected the activity of HI-methyltransferase, as well as HI level in the heart. Under in vitro conditions, all antidepressants, PMZ and CPYR, but not DPHA or TPA, only at high concentrations (10(-3) or 3 X 10(-3M) released HI from both pleural and PMZ did not modulate the pleural mast cells HI-releasing profile of both DOX or DPHA. Chronic treatment with the antidepressants and the H1-antihistaminics decreased slightly but not significantly HI contents in the brains of L-histidine-treated rats. It is suggested that the decrease in the brain HI levels induced by chronic administration of both tricyclic antidepressants and H1-antihistaminics is, most probably, a consequence of HI release from central histaminergic nerve terminals; this release could result from the drug-produced persistent blockade of central H1- and/or H3- (i.e. HI auto-receptors)receptors.

Histamine metabolism in skin of MRL/l mice.

Of several murine autoimmune models, MRL/Mp-lpr/lpr (MRL/l) mice are the most attractive from a dermatopathological point of view, because their skin lesions resemble the erythematous lesions of systemic lupus erythematosus (SLE). In order to clarify the pathogenesis of lupus dermatoses, histamine and its metabolizing activities in the skin of MRL/l mice were investigated. The specific activities of histamine-N-methyltransferase (HMT) in the skin of MRL/l mice were significantly lower than those in the skin of control mice i.e., MRL/Mp-+/+ (MRL/n), C57BL/6J, and BALB/c mice. In the dorsal lesional skin of MRL/l mice, HMT activities were markedly lower than those in normal abdominal skin. In addition, age-related analysis of HMT levels in the dorsal skin of MRL/l mice revealed that HMT activities reached their maximum at the age of 2 or 3 months and then decreased at 4 or 5 months when skin manifestation appeared: however, HMT activities in the abdominal skin increased almost linearly with age. There were no significant differences in histamine content in these mice, and diamine-oxidase activities were not detected in any skin specimens. From these results, it is suggested that impaired histamine metabolism is a particular biochemical feature of the skin of MRL/l mice.