Plasma elevations of histamine and a prostaglandin metabolite in acute asthma

Lesions in the suprachiasmatic nuclei suppress inflammatory mediators in sensitized rats

BACKGROUND

Although bronchial asthma is well known as an inflammatory disease that shows obvious circadian rhythms of airway narrowing, it remains to be elucidated whether the suprachiasmatic nucleus (SCN), a major circadian pacemaker, regulates inflammatory mediators relevant to asthma. Thus, we investigated the effects of electrolytic lesioning of the SCN on the antigen-induced immediate allergic response and the late allergic response (LAR) in male Brown Norway rats, i.e. in a model of allergic inflammation.

METHODS

The immediate allergic response, assessed by the histamine levels in plasma and bronchoalveolar lavage fluid (BALF), and the LAR, assessed by the eosinophilic infiltration into BALF and the lamina propria mucosae of the left main bronchus, were examined in three groups of 18 rats each, including (1) an unoperated control group, (2) a sham SCN-lesioned group, and (3) an SCN-lesioned group.

RESULTS

Both the plasma histamine levels and the number of eosinophils in bronchial tissues in the SCN-lesioned group were significantly lower than those in the other groups. The concentration of histamine and the number of eosinophils in the right BALF showed a similar pattern; however, no significant differences were found. Both plasma adrenaline and noradrenaline levels were highest during the LAR, whereas the corticosterone level was lowest in the SCN-lesioned group; again, no significant differences were obtained.

CONCLUSIONS

These findings indicate that the SCN has a significant effect on the inflammatory mediators relevant to bronchial asthma.

Effect of isolation on classical conditioned histamine release in guinea pigs

To investigate the effect of abrupt or non-abrupt isolation stress on the classical conditioned histamine release, socially isolated or paired guinea pigs underwent conditioning procedures in which ovalbumin (OA) as an unconditioned stimulus (US) and dimethylsulfide (sulfur smelling) as a conditioned stimulus (CS) were simultaneously inhaled, and the plasma histamine levels after the exposure to the CS in a state of isolation or pairing were measured. The plasma histamine levels significantly increased from baseline in response to the CS (P < 0.05), except in the animals which were abruptly isolated during the exposure to the CS. The guinea pigs which were isolated during either the conditioning procedures or the exposure to the CS displayed significantly lower levels of plasma histamine than did the paired animals during both periods (P < 0.01, respectively). The plasma histamine levels in the guinea pigs which were isolated or paired during both periods were significantly higher than those of the control animals which had received the CS and the US separately (P < 0.05 and P < 0.01). A change of social relations, particularly isolation during the presentation of the CS, may have a suppressive effect on immediate asthmatic responses due to the conditioning mechanism.

Effect of experimental influenza A infection on systemic immune and inflammatory parameters in allergic and nonallergic adult subjects

BACKGROUND

The economic impact and medical complication rate of viral upper respiratory infections are well documented, but many of the physiologic, inflammatory, and immune responses to respiratory viruses have only recently been investigated. A previous study demonstrated differential systemic immune and inflammatory responses in allergic rhinitis (AR) and nonallergic rhinitis (NAR) subjects during experimental infection with rhinovirus-39.

OBJECTIVE

The purpose of this study was to compare selected systemic immune and inflammatory responses to experimental influenza A virus (FLU) challenge in seronegative AR and NAR subjects.

METHODS

Peripheral blood was obtained at baseline (study day 0) and 3, 6, 18, and 31 days after intranasal FLU challenge and assayed for leukocyte histamine release, serum immunoglobulins, and plasma histamine.

RESULTS

All subjects were infected, as manifested by viral shedding in nasal secretions and/or seroconversion. FLU infection induced decreases in spontaneous leukocyte histamine release and increases in anti-immunoglobulin E-induced leukocyte histamine release, which were evident at least 1 month after infection, but caused no significant changes in serum immunoglobulins or plasma histamine. There were no differences between AR and NAR subjects for any of the study parameters.

CONCLUSIONS

The results show that intranasal challenge with FLU induces changes in leukocyte histamine release, but not other systemic immune and inflammatory responses.

Blood histamine levels (BHL) in infants and children with respiratory and non-respiratory diseases

BACKGROUND

Blood histamine levels are decreased after severe allergic reactions and in various chronic diseases.

AIMS

To study blood histamine levels in infants and children with acute infectious and non-infectious, non-allergic, disease.

METHODS

Blood histamine levels were investigated by a fluorometric method in infants and children admitted to hospital with bronchiolitis, non-wheezing bronchitis, acute infections of the urinary tract, skin and ear-nose-throat, gastroenteritis, or hyperthermia of unknown aetiology. Results of blood histamine levels and white blood cell counts were compared with those obtained for children recovering from benign non-infectious, non-allergic illnesses.

RESULTS

As compared with control children, white blood cell numbers were significantly increased in children with acute infections of the urinary tract, skin and ear-nose-throat, and were significantly decreased in children with gastroenteritis. Blood histamine levels were significantly lower in children with gastroenteritis and hyperthermia than in children with other diseases and control children. It was not possible to correlate blood histamine levels and the number of blood basophils.

CONCLUSIONS

BHL are significantly decreased in infants and children with acute gastroenteritis and hyperthermia of unknown aetiology. The mechanisms responsible for the decrease in blood histamine levels in children with gastroenteritis and hyperthermia are discussed.

Roles of histamine receptor in a guinea pig asthma model

Histamine plays an important role in bronchoconstriction mediated by histamine receptors which provoke bronchial asthma attack. In this study, we measured H1 and H2 receptors in the guinea pig lung membrane fraction and obtained the following results. The maximum binding (Bmax) of H1 receptors in the guinea pig lung membrane fraction was significantly higher in the OA-sensitized group than that in the non-sensitized group, but affinity (Kd) did not differ between the groups. Otherwise, the maximum binding (Bmax) of H2 receptors in the guinea pig lung membrane fraction was significantly lower in the OA-sensitized group than that in the non-sensitized group. But affinity (Kd) did not differ between the groups. These findings suggest a close association of Histamine receptors both H1 and H2 in the pathology of asthma.

[Potential importance of antileukotrienes in the treatment of asthma and other inflammatory diseases: apropos of a new pharmacological class]

OBJECTIVES

Among the mediators involved in the asthma bronchoconstriction and inflammation mechanisms, there is now substantial evidence that the sulfidopeptide leukotrienes (LTs) are important. Antagonists of their receptors and inhibitors of their synthesis have been developed.

IMPORTANT POINTS

Antagonists of LTs, as well as inhibitors of their synthesis, reduce the LTs actions: bronchoconstriction, bronchial hyperresponsiveness, hypersecretion and inflammation. They produce an acute bronchodilating effect in mild asthma, reduce the hyperresponsiveness responses due to allergens, aspirin and cold and dry air, and also cutaneous and gastrointestinal reactions. Oral administrations tested during 4 or 6 weeks diminish the use of the beta-agonists, decrease the asthma symptom scores and other inflammatory signs.

PERSPECTIVES AND PROJECTS

More studies for longer periods, double blind trials and comparisons with classical treatments will be necessary to define the real place of LTs antagonists in the treatment of asthma. So their efficacy has to be confirmed as well as their good tolerance profile (particularly for hepatic functions).

CONCLUSION

Antagonists of receptors and synthesis inhibitors of LTs have known a recent and important development. They constitute a new therapeutic class: further studies are needed to better define the place of these new drugs in the treatment of asthma and other inflammatory diseases.

Effect of rhinovirus 39 (RV-39) infection on immune and inflammatory parameters in allergic and non-allergic subjects

The economic impact and medical complication rate of the common cold are well documented, but many of the physiological, inflammatory, and immune responses to common cold viruses have only recently been investigated. The purpose of this study was to compare selected systemic immune and inflammatory responses to experimental rhinovirus (RV)-39 challenge in seronegative allergic rhinitis and non-allergic rhinitis subjects. Peripheral blood was obtained before (baseline), during (acute), and 23 days after (convalescent) RV-39 intranasal challenge and assayed for leucocyte histamine release, serum immunoglobulins, allergen-specific IgE antibodies, plasma histamine, and platelet aggregation. All subjects were infected, as manifested by viral shedding in nasal secretions or seroconversion. RV-39 infection induced significant acute increases in serum IgE, leucocyte histamine release, and platelet aggregation, but caused no changes in serum IgG, serum IgA, serum IgM, and plasma histamine. The first change was confined to the allergic rhinitis subjects. There was no evidence that the acute rise in total serum IgE was due to an elevation of a pre-existing, pollen-specific serum IgE antibody. The results show that intranasal challenge with RV-39 induced changes in systemic immune and inflammatory parameters with a unique response pattern in allergic rhinitis subjects.

Eicosanoids and asthma: an update

There have been significant advances in our understanding of the role of eicosanoids as mediators in inflammation since their discovery over 50 years ago. Our more recent understanding of asthma as an inflammatory disease has led to the appreciation of eicosanoids potentially being pivotal mediators in promoting some of the changes in asthma. Of particular importance are the cysteinyl LTs in producing bronchospasm and bronchial hyperresponsivenss, and PGE2 in modulating the bronchospastic and inflammatory response. Evidence from clinical studies suggests that other eicosanoids may also contribute, but their importance is secondary and their relative contributions vary between individuals. The development of new drugs based on our partial understanding of the role that eicosanoid mediators may play in asthma promises new approaches to the treatment of this common chronic inflammatory condition.

Inhibition by thromboxane antagonists of airway hyperresponsiveness to histamine induced by 13,14-dihydro-15-keto-PGF2 alpha in guinea-pigs

We studied the effect of intravenous administration of 13,14-dihydro-15-keto-prostaglandin (PG) F2 alpha on airway responsiveness to histamine and airway wall thickening in guinea-pigs. Guinea-pigs were killed and the lungs were fixed in formalin. Slides from paraffin-embedded sections of the lungs were stained and the airways that were cut in transverse section were measured by tracing enlarged images using a digitizer. Moreover, airway resistance (Raw) was determined by a pulmonary mechanics analyser and we calculated two indices, an index of airway wall thickening and the one of airway hyperresponsiveness to histamine, from changes of baseline-Raw and peak-Raw following intravenous administration of histamine before and after the intravenous administration of 13,14-dihydro-15-keto-PGF2 alpha. Intravenous administration of 10 micrograms/kg 13,14-dihydro-15-keto-PGF2 alpha for 1 h did not induce an increase of the relative thickness of the airway wall by the histological examination. In analysis of airway function, intravenous administration of 10 micrograms/kg 13,14-dihydro-15-keto-PGF2 alpha for 1 h induced airway hyperresponsiveness to histamine without airway wall thickening. Thromboxane A2 (TXA2) receptor antagonists ONO-NT-126 and ONO-8809 inhibited the 13,14-dihydro-15-keto-PGF2 alpha-induced airway hyperresponsiveness to histamine, suggesting that the effect of 13,14-dihydro-15-keto-PGF2 alpha on bronchial hyperresponsiveness is likely to be mediated through TXA2.

Potentiation of the antireactive, antiasthmatic effect of inhaled furosemide by inhaled lysine acetylsalicylate

Nonsteroid antiinflammatory drugs interfere with the diuretic activity of furosemide, implying that this effect is at least partially dependent on renal prostaglandin synthesis. To investigate whether prostaglandin production could also modulate the bronchial antireactive activity of this diuretic drug, we investigated the effect of inhaled lysine acetylsalicylate (162 mg) and of furosemide (18 mg), alone and in combination, on the bronchial obstructive response to ultrasonically nebulized water in asthmatic patients. The study was also prompted by the conflicting results obtained in previous studies of oral nonsteroid antiinflammatory drugs. Fifteen asthmatic patients underwent bronchial challenge with a mist of ultrasonically nebulized distilled water at the same time of day on four occasions, 2-4 days apart, 15 min after premedication according to a double-blind, randomized protocol. After placebo, mean PD15 to water mist did not differ from a preliminary test (2.1 +/- 0.2 and 2.5 +/- 0.4 ml, M +/- SE, respectively). After lysine acetylsalicylate, mean PD15 rose to 5.0 +/- 0.7 ml (2.8 +/- 0.6 times higher than placebo); after furosemide, to 9.0 +/- 1.5 ml (4.4 +/- 0.9 times over placebo); and after the two drugs in combination, to 32.2 +/- 5.6 ml (16.3 +/- 3.0 times higher than placebo). Similar results were obtained with inhaled indomethacin, whereas sodium salicylate had no effect. These data indicate that the bronchial antireactive activity of inhaled furosemide is greatly enhanced by inhaled lysine acetylsalicylate through a mechanism which probably involves inhibition of the local synthesis of prostaglandins, and could have therapeutic implications.

Human synovial mast cell involvement in rheumatoid arthritis and osteoarthritis. Relationship to disease type, clinical activity, and antirheumatic therapy

Mast cells were isolated by enzymatic digestion of synovium obtained from 48 patients with rheumatoid arthritis (RA) and 42 patients with osteoarthritis (OA). A significantly lower percentage of stainable synovial mast cells was obtained by tissue digestion from patients with clinically active RA compared with those with less active disease. The 54 patients treated with nonsteroidal antiinflammatory drugs had a significantly lower percentage of stainable synovial mast cells in cell suspension than did the other 36 patients. When anti-IgE antibody was used as a secretagogue in vitro, significantly greater histamine release was observed from synovial mast cells of RA patients compared with OA patients. Greater histamine release in response to anti-IgE was observed in the RA patients with more clinically active disease and those who were treated with prednisone, compared with RA patients without these features. Synovial mast cells of RA patients treated with a disease-modifying antirheumatic drug had a significantly lower mean histamine content than did cells from patients not receiving such treatment. Our data suggest that there are differences between synovial mast cells from tissues of patients with RA and OA and suggest that synovial mast cells may be activated in clinically active RA. In addition, the data indicate an effect of systemic antirheumatic therapy on mast cells isolated from synovium of patients with arthritis.

Plasma elevations of histamine and a prostaglandin metabolite in acute bronchiolitis

Acute bronchiolitis (AB) is a common lung disease in infants manifested clinically by dyspnea and wheezing. The purpose of this study was to measure simultaneous plasma levels of histamine and a stable prostaglandin F2 alpha metabolite [13,14-dihydro-15-keto-PGF2 alpha (PG metabolite)], by radioenzymatic and radioimmunoassays, respectively, during and after recovery from AB. Blood was obtained from 15 infants during AB and from 14 and 9 of these infants when re-evaluated 6 and 18 months later, respectively. Mean (+/- 1 SEM) pre- and posttherapy (inhaled isoetharine) histamine levels (pg/ml), 1,923 +/- 980 and 1,035 +/- 250 during AB, respectively, were markedly higher than those of the same nonwheezing subjects at 18 months, 360 +/- 125, but unexpectedly lower than those at 6 months, 9,210 +/- 5,242. Of the 14 infants evaluated at 6 months, 7 had elevated histamine levels along with histories of recurrent wheezing after AB. Similarly, pre- and posttherapy PG metabolite levels (pg/ml), 1,033 +/- 419 and 1,613 +/- 527, respectively, were significantly higher than those of the same children when asymptomatic at 6 (27 +/- 7) and 18 months (68 +/- 25). Pre- and posttherapy levels of histamine and PG metabolite were higher than those of normal and sick, nonwheezing infants. These data indicate that histamine and PG metabolite are detectable in plasma during AB and suggest a role for histamine and PGF2 alpha in the pathogenesis of airways inflammation in AB.

Plasma prostaglandin levels from bronchial asthmatic patients assayed by 9-anthryldiazomethane-HPLC method

Plasma prostaglandin (PG) and thromboxane (Tx) levels from bronchial asthmatic patients were assayed by 9-anthryldiazomethane reversed-phase high-performance liquid chromatography method. TxB2 levels from stable bronchial asthmatic patients were significantly higher than those from normal healthy subjects. PGF2 alpha levels were significantly elevated in atopic patients compared with nonatopic ones. PG patterns differed between asthmatic and nonasthmatic conditions in the same patients. PGF2 alpha levels were significantly elevated in the patients with spontaneous attacks compared with those without attacks and 6-keto PGF1 alpha levels were significantly lower in bronchial asthmatic patients having attacks than in the patients without attacks. There were no significant differences of PG levels between mild and moderate asthmatic subjects. Aminophylline injection in patients with mild spontaneous attacks had no significant effects on PG levels which were compared before and after injection.

Increases in plasma concentrations of a prostaglandin metabolite in acute airway obstruction

Plasma concentrations of a stable prostaglandin F2 alpha metabolite were measured by radioimmunoassay during and after recovery from acute airway obstruction in 15 infants. Mean (SEM) metabolite concentrations (ng/l) in plasma obtained both before (1033 (418)) and after (1470 (413)) initial treatment for airway obstruction were significantly higher than those obtained from the same subjects after resolution of the obstruction--25.5 (6.6)--and those obtained from two comparison groups. Infants positive for respiratory syncytial virus (mean 1122 (227)) had significantly higher concentrations than those who were negative (207.6 (46)). Additionally, seven subjects with a history of recurrent wheezing after resolution of airway obstruction had a significantly higher mean level (3500 (1400)) during attacks of airway obstruction than those without (600 (100)). These data suggest that prostaglandin F2 alpha mediates respiratory inflammation in airway obstruction and that trials of specific anti-inflammatory agents for the treatment of airway obstruction may be warranted.

The wheezing infant

In summary, wheezing is a common manifestation of viral respiratory tract disease in infancy. The precise pathogenetic mechanisms of virus-induced wheezing and its sequelae are not clear, although recent reports about participation of the cellular and humoral immune systems are promising. Although therapies like those used to treat asthma are employed in the treatment of virus-induced wheezing in infancy, their efficacy remains controversial in bronchiolitis. Recently developed agents with antiviral properties are promising and the choice of any of these agents in a therapeutic regimen should be individualized. Antiviral agents during acute infections may modify the long-term sequelae. Clearly, much work needs to be done to elucidate pathogenetic mechanisms, and to develop new, safe, and effective anti-inflammatory agents for the therapy of these disorders.