Diamine oxidase activity and histamine release in dogs following acute mesenteric artery occlusion

Food Intolerance: The Role of Histamine

Histamine is a natural amine derived from L-histidine. Although it seems that our knowledge about this molecule is wide and diverse, the importance of histamine in many regulatory processes is still enigmatic. The interplay between different types of histamine receptors and the compound may cause ample effects, including histamine intoxication and so-called histamine intolerance or non-allergic food intolerance, leading to disturbances in immune regulation, manifestation of gastroenterological symptoms, and neurological diseases. Most cases of clinical manifestations of histamine intolerance are non-specific due to tissue-specific distribution of different histamine receptors and the lack of reproducible and reliable diagnostic markers. The diagnosis of histamine intolerance is fraught with difficulties, in addition to challenges related to the selection of a proper treatment strategy, the regular course of recovery, and reduced amelioration of chronic symptoms due to inappropriate treatment prescription. Here, we reviewed a history of histamine uptake starting from the current knowledge about its degradation and the prevalence of histamine precursors in daily food, and continuing with the receptor interactions after entering and the impacts on the immune, central nervous, and gastrointestinal systems. The purpose of this review is to build an extraordinarily specific method of histamine cycle assessment in regard to non-allergic intolerance and its possible dire consequences that can be suffered.

Mesenteric ischemia-reperfusion injury: clearly improved hemodynamics but only minor protection of the rat small intestine by (sub)therapeutic heparin sodium and enoxaparin doses

BACKGROUND

Tissue protection against ischemia (I)/reperfusion (R) injury by heparins can be due to their anticoagulant and/or non-anticoagulant properties. Here we studied the protective potential of the anticoagulant and the non-anticoagulant features of heparin sodium (HepSo) and enoxaparin (Enox) against mesenteric I/R injury in a rat model.

MATERIALS AND METHODS

Mesenteric I/R was induced in rats (n = 6 per group) by superior mesenteric artery occlusion (SMAO; 90 min) and reopening (120 min). Therapeutic/clinical and subtherapeutic/non-anticoagulant doses of HepSo (0.25 mg/kg bolus + 0.25 mg/kg × h; 0.05 mg/kg bolus + 0.1 mg/kg × h) or Enox (0.5 mg/kg bolus + 0.5 mg/kg × h; 0.05 mg/kg bolus + 0.1 mg/kg × h) were administered intravenously starting 30 min before SMAO to the end of reperfusion. Systemic/vital and intestinal microcirculatory parameters were measured during the whole experimental procedure, those of small intestine injury at the end.

RESULTS

During intestinal reperfusion, mean arterial blood pressure and heart rates were significantly increased by HepSo and, less effectively, by Enox, in a dose-dependent manner. Intestinal microcirculation was only affected by the therapeutic HepSo dose, which decreased the microvascular flow and S(O2) during reperfusion. The subtherapeutic Enox treatment, as opposed to any HepSo dose, most effectively diminished I/R-induced intestinal hemorrhages, myeloperoxidase activity (as a measure of neutrophil invasion), and histopathological changes.

CONCLUSION

Therapeutic but, to a lesser extent, also the subtherapeutic doses of both HepSo and Enox clearly improve hemodynamics during mesenteric reperfusion, while intestinal protection is exclusively provided by Enox, especially at its subtherapeutic dose. Alterations in intestinal microcirculation are not responsible for these effects. Thus, non-anticoagulant Enox doses and, preferably, heparin(oid)s unable to affect coagulation, could diminish clinical risks of I/R-induced gastrointestinal complications.

Pacing-induced delayed protection against arrhythmias is attenuated by aminoguanidine, an inhibitor of nitric oxide synthase

1. Cardiac pacing, in anaesthetized dogs, protects against ischaemia and reperfusion-induced ventricular arrhythmias when this is initiated 24 h after the pacing stimulus. Now we have examined whether this delayed cardioprotection afforded by cardiac pacing is mediated through nitric oxide. 2. Twenty-two dogs were paced (4 x 5 min periods at 220 beats min(-1)) by way of the right ventricle, 24 h prior to a 25 min period of coronary artery occlusion. Nine of these dogs were given the inhibitor of induced nitric oxide synthase, aminoguanidine (50 mg kg(-1) i.v.), 0.5 h prior to coronary artery occlusion. Sham-operated non-paced dogs with and without aminoguanidine treatment served as controls. 3. Pacing markedly (P<0. 05) reduced arrhythmia severity (ventricular fibrillation, VF, during occlusion 15%; survival from the combined ischaemia-reperfusion insult 62%) compared to control, sham-operated, unpaced dogs (VF during occlusion 58%; survival 17%). This protection was attenuated by the administration of aminoguanidine prior to coronary artery occlusion (survival from the combined ischaemia-reperfusion insult 11%, which was significantly (P<0.05) less than in the paced dogs not given aminoguanidine and similar to the controls). Aminoguanidine had no significant effects on coronary artery occlusion when given to dogs that had not been paced. In the dose used aminoguanadine transiently elevated systemic arterial pressure by a mean of 20 mmHg and reduced heart rate by a mean of 22 beats min(-1). 4. These results suggest that nitric oxide, probably derived from induced nitric oxide synthase, contributes significantly to the delayed cardioprotection afforded by cardiac pacing.

Inhibition of post-ischemic reperfusion injury of the kidney by diamine oxidase

To elucidate the role of histamine in the pathogenesis of post-ischemic reperfusion injury of tissues, the effect of diamine oxidase (DAO) was studied on the changes in renal functions induced by 30 min occlusion followed by reperfusion of the renal vessels of unilaterally nephrectomized rats. Kinetic analysis using radiolabeled albumin revealed that vascular permeability of the kidney increased markedly after reperfusion. Although the intensity of neutrophil-dependent chemiluminescence of the blood remained unchanged during the occlusion, it increased significantly after reperfusion. Histological examination revealed a marked degeneration of glomeruli and proximal tubules in the reperfused kidney. Transtubular transport of phenolsulfophthalein (PSP) decreased markedly after reperfusion with concomitant increase in plasma levels of creatinine. Intravenously administered DAO markedly inhibited the reperfusion-induced increase in vascular permeability, preserved the structure of the kidney and normalized the rate of clearance of PSP and creatinine. Combined use of diphenylhydramine and ranitidine also inhibited the reperfusion injury of the kidney. These results suggested that histamine and its receptors might play critical roles in post-ischemic reperfusion injury of the kidney.

Diamine oxidase in relation to diamine and polyamine metabolism

Diamine oxidase catalyzes the oxidative deamination of short chain aliphatic diamines, like putrescine, and histamine. The enzyme is rate-limiting in the terminal catabolism of polyamines, which are endogenous polycations important for cell growth and differentiation. This review examines the behavior of diamine oxidase in mammalian tissues in relation to diamine and polyamine metabolism under physiological and pathological conditions. The role of diamine oxidase in the control of putrescine levels in growing tissues and the known mechanisms responsible for the enzyme expression are also described.

Histamine does not mediate mucosal permeability changes after subclinical intestinal ischemia-reperfusion injury

Subclinical intestinal ischemia-reperfusion injury (IRI) increases mucosal permeability, and may be an important mechanism in the etiology of necrotizing enterocolitis. The current study was designed to assess the role of histamine in mediating this phenomenon. Six-week-old rats underwent 10-minute superior mesenteric artery occlusion (SMAO) or sham operation, and ileal mucosal permeability to 51Cr EDTA was measured 30 minutes after reperfusion. Rats were pretreated with intravenous saline, mepyramine (6 mg/kg), or ranitidine (5 mg/kg). SMAO resulted in a significant increase in permeability compared to sham, which was not attenuated by either of the histamine antagonists. In a second experiment, mucosal permeability to 51Cr EDTA was measured in 6-week-old rats during aortic infusion of saline or histamine (0.5 mg/kg/min). There was no significant increase in permeability as a result of histamine infusion. In a third experiment, 6-week-old and 10-day-old rats underwent sham or 10-minute SMAO, and both portal vein and ileal tissue histamine levels were measured 30 minutes after reperfusion. There was no significant difference between sham and SMAO with respect to portal vein histamine or tissue histamine at either age.

IN CONCLUSION

(1) increased permeability was not blocked by either H1 or H2 blockers; (2) histamine infusion did not increase permeability; and (3) SMAO did not increase portal vein or tissue histamine levels. These data suggest that histamine does not play a role in mediating the increase in permeability after subclinical IRI in this model.

Inhibition of post-ischemic reperfusion injury of the small intestine by diamine oxidase

To elucidate the role of diamines in the pathogenesis of post-ischemic reperfusion-induced tissue injury, the effect of diamine oxidase was studied in the rat whose superior mesenteric artery was occluded for 15 min followed by 30 min reperfusion. Kinetic analysis using radiolabeled albumin revealed that the mucosal permeability of the reperfused small intestine increased significantly. Histological examination of the reperfused intestine revealed a marked degeneration of its mucosal layer. Intravenous administration of diamine oxidase inhibited the reperfusion-induced increase in mucosal permeability of the intestine almost completely and preserved the structure of the small intestine. H1-antagonist chlorphenilamine and H2-antagonist famotidine also inhibited the reperfusion injury of the small intestine. These and other results suggested that extracellular diamines might play critical roles in post-ischemic reperfusion-induced injury of the small intestine.

Plasma and mucosal histamine after small bowel transplantation in rats

During the course of a study on preservation of small bowel transplants in rats, the hypothesis that histamine may play a role in graft damage has been investigated. Plasma and mucosal histamine levels have been measured after storage and reperfusion of Lewis rat small bowel transplants which have received an intravascular flush of saline or of one of the tissue preservation media, hypertonic citrate or University of Wisconsin solution. Plasma histamine concentration was unchanged from a control value of 23.2 +/- 2.6 ng/ml 15 min after reperfusion of grafts, whether fresh or stored for 24 h or for 48 h. Mucosal histamine levels in the grafts fell, however, from a control value of 371.0 +/- 22.9 ng/g tissue, first on storage then further after 15 min reperfusion. No differences were found in these parameters of histamine release between any of the preservation media. It is suggested that histamine may play a role in storage and reperfusion damage to small bowel transplants.

Intestinal diamine oxidase levels reflect ischemic injury

Mucosal diamine oxidase (DAO) decreases during intestinal ischemia and may be a useful marker of intestinal ischemic injury. Tissue DAO activity and histologic changes were studied in intestinal segments taken from the midpoint of the small intestine before and 2, 4, and 24 hr after manipulation of the intestinal blood supply in 24 mongrel dogs. Intestinal DAO activity decreased significantly (17 +/- 21% of control value) 24 hr after SMA ligation and was associated with abnormal histology (histology score 7.8 +/- 2.9 at 24 hr vs 0.3 +/- 0.5 at 0 hr). SMA occlusion for 2 hr resulted in a significant decrease in DAO activity (45 +/- 36% of control value) 4 hr after manipulation which returned to normal at 24 hr, as did the histologic injury. Ligation of both the mesenteric arteries and veins resulted in a more rapid decrease in DAO activity. Decreased DAO activity correlated with the extent of histologic injury. Intestinal ischemia is associated with decreased intestinal DAO activity, which is influenced by the mechanism and duration of intestinal ischemia.

Serum enzyme levels during intestinal ischemia

Because the intestinal mucosa is most sensitive to ischemia, serum levels of mucosal enzymes, such as diamine oxidase, may be most likely to indicate intestinal ischemia. Our aim was to compare serum levels of mucosal (diamine oxidase, alkaline phosphatase) and seromuscular (creatinine phosphokinase, lactic dehydrogenase, serum glutamic oxaloacetic transminase) enzymes during intestinal ischemia of varying extent and duration in dogs. Group 1 (n = 6) underwent sham laparotomy. Group 2 (n = 8) had 50% of the small intestine devascularized. Group 3 (n = 8) had the superior mesenteric artery occluded for 2 hours and released. Group 4 (n = 8) had the superior mesenteric artery ligated. Serum samples were obtained before and 2, 4, 8, and 24 hours after operation, and histologic specimens were examined at 4 hours. Creatinine phosphokinase levels became elevated within 4 hours of ischemic injury in group 2 (223 +/- 197 vs. 68 +/- 26, p less than 0.05) and group 4 (212 +/- 136 vs. 76 +/- 29, p less than 0.05). Significant elevation of serum enzymes levels, except diamine oxidase, occurred in groups 2, 3, and 4 at 24 hours, including those with normal histology after temporary superior mesenteric artery occlusion. Thus seromuscular enzymes, particularly creatinine phosphokinase, were more likely to be elevated during intestinal ischemia. Enzyme levels were not influenced by the extent and reversibility of the ischemic injury.

Inhibition of histamine N-methyltransferase (HNMT) in vitro by neuromuscular relaxants

There have been reports of hypotension and flushing following vecuronium administration. The etiology of these symptoms, which are similar to those of histamine release, is not clear. The steroidal neuromuscular relaxants (NMRs), unlike muscle relaxants structurally similar to curare, have been shown not to cause histamine release after the administration of typical clinical doses. Histamine levels in plasma reflect a balance between release and catabolism. In humans, histamine N-methyl-transferase (HNMT) is the enzyme primarily degrading for histamine. Therefore, we performed in vitro kinetic studies of purified HNMT to determine the effects of the steroidal and curare-like NMRs and also of gallamine on histamine catabolism. We demonstrated that all NMRs tested were inhibitors of HNMT in vitro. The inhibition was competitive with respect to the cosubstrate S-adenosyl-L-[3H-methyl] methionine, and noncompetitive with respect to histamine. The rank order of inhibition was vecuronium greater than pancuronium greater than gallamine greater than d-tubocurarine greater than metocurine greater than atracurium greater than pipecuronium, with Ki values ranging from 1.2 to 44.8 microM. Our data suggest that HNMT-based radioenzymatic assays for histamine should be susceptible to inhibition by concurrent use of NMRs, particularly vecuronium.

Intestinal diamine oxidases and enteral-induced histaminosis: studies on three prognostic variables in an epidemiological model

The danger of luminal histamine administered orally or formed in the intestinal fluid by bacteria has long been neglected. However, the demonstration of blocking intestinal diamine oxidase (DAO) by a variety of common drugs has revived the discussion and has created a new disease concept: enteral-induced histaminosis. In an animal model the three central prognostic variables of this disease concept (large amounts of histamine in food to make the individual ill, blocking of DAO by commonly used drugs, and the relationship between increased plasma histamine levels and disease manifestation by exogenous histamine application) were tested with randomized trials in vivo and biochemical tests in vitro using semipurified enzymes from pig and man. In the first trials authentic histamine in quantities similar to that in normal amounts of food or cheese bought from a supermarket produced life-threatening reactions if the DAO was inhibited by pretreatment with aminoguanidine. In the second series of experiments in vitro a numerous commonly used drugs was shown to inhibit both the porcine and human enzyme. Some of the inhibitors were really strong, such as dihydralazine, chloroquine, pentamidine, cycloserine, clavulanic acid, dobutamine, pancuronium and others. The type of inhibition was sometimes competitive as in the case of dihydralazine and pancuronium, sometimes non competitive (e.g. pentamidine) which may be important for long-term treatment. In the third group of experiments a relationship between the dose of i.v. injected histamine and the elevation in plasma histamine levels and clinical symptoms in pigs was demonstrated. Hence, elevated plasma histamine in pigs acts as a pathogenetic factor for the disease manifestation. It is concluded that after modelling enteral-induced histaminosis in an animal the trias of variables shown in this study should be consequently investigated in man.

Effect of acute ethanol administration on diamine oxidase activity in maternal, embryonal and fetal tissues

Pregnant rats were acutely treated with ethanol to study the influence of this drug on diamine oxidase activity of maternal, embryonal, and fetal tissues. When ethanol was given on day 12 of gestation, enzyme activity was unmodified in placenta and embryo, whereas it was reduced by 38 and 31%, respectively, in maternal liver and plasma at 3 h. When ethanol was given on day 18 of gestation, diamine oxidase activity diminished in maternal liver, plasma and placenta by about 35-40% at 6 h. Moreover, in the fetus ethanol caused a 35% diminution of enzyme activity in liver at 6 h and a 45% stimulation in brain at 3 h, and of about 65% at 6-12 h. These data may be of interest in view of the physiological role of diamine oxidase in the oxidation of the large amounts of amines produced during pregnancy.

Inhibition of human and canine diamine oxidase by drugs used in an intensive care unit: relevance for clinical side effects?

Three hundred and forty-one drugs, commonly used in intensive care units (ICU), were chosen for an investigation of possible activation or inhibition of the histamine metabolizing enzyme diamine oxidase (DAO). After examination of 164 substances, using both canine and human DAO in an in vitro screening test, 61 agents inhibited DAO activity to various degrees. Of these, 44 inhibited the enzyme from both species, 4 inhibited the canine enzyme only and 13 the human DAO only. No compound tested was able to enhance the enzyme activity. The inhibiting agents included representatives of all major therapeutic groups. A particularly strong inhibition was observed with the neuromuscular blocking drugs d-tubocurarine, pancuronium and alcuronium, however, the other commonly used neuromuscular blocking drug, suxamethonium, was without effect. Similarly with the cephalosporines, cefotiame and cefuroxime caused a marked inhibition of the human DAO activity, whereas another regularly-used substance of this class, cefotaxime, inhibited neither the human nor the canine enzyme in concentrations up to 10(-3) M. The observation that within a given therapeutic group some members inhibit and others do not, could be useful in choosing a therapy concept which minimizes the risk of a more severe 'histamine' reaction in seriously ill patients.

Diamine oxidase (histaminase). A circulating marker for rat intestinal mucosal maturation and integrity

Diamine oxidase (histaminase) is an enzyme found in high concentrations in the intestinal mucosa of humans and other mammalian species. We investigated whether plasma and mucosal levels of diamine oxidase activity reflect both the maturational status of the mucosa during its development in the newborn rate and the degree of mucosal damage during its injury in the adult rat. Litter mates were reared under identical conditions and killed at different ages from day 0 to day 40 after birth. Diamine oxidase in the small intestine was low at birth, increased gradually with age, reached a peak at 22 d, and then remained at normal adult levels, similar to the developmental patterns of maltase and sucrase. Plasma diamine oxidase rose in parallel with intestinal levels (n = 500, r = 0.84, P less than 0.001), reached a peak at 24 d, and then remained at normal adult levels. Diamine oxidase activity in 15 nonintestinal tissues was less than 5% of ileal mucosal activity, and no nonintestinal activities showed increase with age. Adult rat intestinal loops were perfused with hyperosmolar sodium sulfate solutions to produce selective damage to villus mucosa. With increasing mucosal damage, there was a progressive decrease in the enzyme activities studied; first, lactase levels fell, then maltase and sucrase, and finally mucosal and plasma diamine oxidase activity levels fell. The decrease in plasma diamine oxidase reflected the degree of mucosal damage (n = 29, P less than 0.04). Diamine oxidase activity is thus unique among intestinal mucosal enzymes studied to date in that circulating levels can serve as a marker of mucosal maturation and integrity.

H1 + H2-receptor antagonists for premedication in anaesthesia and surgery: a critical view based on randomized clinical trials with Haemaccel and various antiallergic drugs

Histamine release by drugs used in anaesthesia and surgery has been often demonstrated in human volunteers, but only occassionally in patients. Three questions arose from these studies. (1) Is the incidence of histamine release high in patients during routine anaesthesia and surgery? (2) Can the clinical effects of histamine release in man be prevented by H1 + H2-receptor antagonists? (3) Are there any side-effects of such a premedication? These problems were investigated in patients and volunteers by randomized controlled clinical trials using only one of the histamine-liberating drugs in man, the plasma substitute Haemaccel. This drug was chosen because it causes a reproducible histamine release in man and because its mechanism of action in man is largely known. (1) Out of 600 orthopaedic patients 30 (5%) showed anaphylactoid reactions following Haemaccel infusion. 26 of these had a histamine release of more than 1 ng histamine/ml plasma. Using predictive values this gives an efficiency of the test by nearly 98%. (2) In volunteers the combination of an H1-plus H2-receptor antagonist (dimethypyrindene and cimetidine) completely prevented the clinical effects of histamine release by Haemaccel (9 allergoid and anaphylactoid reactions in the control group, none in the H1 + H2-group). The incidence of histamine release, however, remained unchanged. (3) The premedication was found to release histamine itself. Cimetidine was effective when given alone but especially in combination with chlorpheniramine (4 events out of 7 applications). The clinical side-effects of these premedication were mild since apparently the free histamine was largely blocked at the receptor sites. It is concluded that premedication with a combination of H1- and H2-receptor antagonists is indicated due to the high incidence of histamine release during anaesthesia and surgery induced by various drugs and treatments. Such premedication is effective but associated with mild side-effects. For this reason more extended clinical trials with dimethpyrindene plus cimetidine in patients are necessary before this premedication can be generally recommended.

Human intestinal diamine oxidase: substrate specificity and comparative inhibitor study

For an 80-fold purified preparation of human intestinal diamine oxidase the optimum conditions of incubation, the substrate and the inhibitor specificity were tested. Putrescine was the most favoured substrate but N tau-methylhistamine and 2-methylhistamine were metabolized at optimum conditions with nearly the same velocity. Histamine reached about 50% of the reaction velocity of putrescine. Aminoguanidine and semicarbazide inhibited the human intestinal enzyme like a classical diamine oxidase. However, a distinct inhibition of human intestinal and pea seedling diamine oxidase was observed in presence of beta-aminopropionitrile (weak inhibition of the human enzyme, strong inhibition of pea seedling diamine oxidase) and burimamide (strong inhibition of human intestinal enzyme, nearly no influence on pea seedling diamine oxidase). It is proposed to differentiate on the basis of functional considerations diamine oxidases with more histamine detoxicating activities from those being more involved in regulating polyamine levels in growing tissues.

Comparison of alterations in the histamine-diamine oxidase system during acute intestinal ischaemia in pigs, dogs and rabbits; evidence for a uniform pathophysiological mechanism?

Among various vasoactive substances histamine was also suggested to induce circulatory arrest following superior mesenteric artery occlusion. Thus the involvement of the histamine-diamine oxidase system was studied in intestinal ischaemia using three animal species. In pigs, dogs and rabbits aminoguanidine, the specific inhibitor of diamine oxidase, shortened the survival time after mesenteric infarction. Under these conditions the diamine oxidase activity in the intestinal wall was reduced in animals treated by saline whereas the histamine content was not altered significantly. Plasma histamine levels were increased considerably in the portal vein of pigs during the revascularization period if the animal were pretreated by aminoguanidine. Similar findings were obtained in dogs. It was concluded that in all three species investigated the diamine oxidase protects the organism against the deleterious effects of at least one of its vasoactive substrates-histamine.

[Prospective controlled clinical trials in surgery. controversial issues in motivation and performance (author's transl)]

Controversial aspects in prospective controlled trials in surgery can be detected at various stages in the course of this research work, such as in motivation, planning and performance as well as in assessment and evaluation of the results. Especially the introduction of control groups, randomization and "blindness" of patients, operators and doctors running the follow-up are subjects of a controversial discussion. Subthreshold arguments for defenders and eniers of the trial are taken from different theories of science, such as empirism and rationalism which are more effective in the daily routine work than expected. Provided that convincingly only therapeutic and diagnostic procedures are compared which were considered as equi-effective and reliable to the same extent according to the best and most complete knowledge available it is ethically justified to perform controlled randomized trials. It should, however, not be expected that they (always) produce differences between treatment of high degree of difference. The aim of the controlled trials is not the introduction of sensational novelties into medicine, but the abolition and prevention of unnecessary and unworthy modes.

Histamine and pancreatitis: increase of plasma histamine levels in dogs with Pfeffer preparation and influence of aminoguanidine on the survival time

Histamine release could be shown in 50% of the dogs suffering from acute haemorrhagic pancreatitis in Pfeffer's preparation. The survival time of these dogs was shorter by about 50% than that of animals without alteration of the plasma histamine levels. The powerful diamine oxidase blocker aminoguanidine diminished the incidence of severe pancreatitis in the dogs without influencing survival time. As in animals treated by saline histamine release could be shown in 50% of the aminoguanidine-treated dogs in which higher plasma histamine levels were determined than in saline-treated animals. The survival time of the dogs with histamine release, however, was not different from that of animals with normal plasma histamine levels throughtout the experiment. The actions of aminoguanidine in Pfeffer's preparation seemed to be rather complex. Contrasting effects on the development of pancreatitis and on histamine inactivation may have influenced the survival time in different directions.