Reduced effect of epinephrine on circulating eosinophils in asthma and after beta-adrenergic blockade or Bordetella pertussis vaccine. With a note on eosinopenia after methacholine

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.

Ageing, late-onset asthma and the beta-adrenoceptor

Late-onset asthma in old age is a common clinical problem. There are similarities between receptor and post-receptor beta 2-adrenoceptor abnormalities reported in young asthmatics and in elderly normal subjects. Recent evidence lends some support to the idea of the 'aging' beta 2-adrenoceptor as a contributory factor in the development of late-onset asthma, although questions of the validity of the peripheral mononuclear cell model and of receptor tachyphylaxis to intrinsic and extrinsic beta-adrenoceptor agonists remain unresolved. Further work should focus on in vivo studies of airway receptor function and on beta 2-adrenoceptor-mediated pathways other than smooth muscle-related bronchoconstriction.

Safety of bronchoalveolar lavage and bronchial biopsies in patients with asthma of variable severity

The safety of fiberoptic bronchoscopy, bronchoalveolar lavage (BAL), and bronchial biopsies has been questioned in asthma, and current recommendations indicate that bronchoscopies should only be performed in mild to moderate asthma. Moreover, in most studies patients receive premedication with nebulized bronchodilators that may enhance the safety of the procedures. The purpose of this study was to determine (1) whether the overall safety of fiberoptic bronchoscopy, BAL, and bronchial biopsies in mild to moderate asthma could be extended to patients with more severe asthma and (2) whether these procedures are safe without premedication with nebulized bronchodilators. A group of 50 patients with asthma of variable severity (FEV1 ranging from 37 to 107% of predicted values) and 25 healthy volunteers were studied. Bronchoscopy, BAL (250 ml), and four bronchial biopsies were performed in a standardized manner, without premedication with a nebulized bronchodilator, by the same investigator. Safety was assessed by clinical follow-up, continuous recording of arterial oxygen saturation during the procedure with a digital oximeter, and measuring FEV1, FEF25-75, and FVC just before and 5 min after bronchoscopy. Arterial oxygen saturation decreased in asthmatic patients from 97% (range 91 to 99%) (T1) to 92% (range 79 to 98%) (T8) (ANOVA, Fisher's PLSD) and in control subjects from 97% (range 94 to 99%) (T1) to 93% (range 88 to 98%) (T8) (ANOVA, Fisher's PLSD). The fall in arterial oxygen saturation was not significantly different between asthmatic and normal subjects, and there was no correlation between arterial oxygen desaturation and the severity of asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Eosinophilia caused by administration of L-tryptophan to animals with adrenal dysfunction

We have investigated an animal model of eosinophilia-myalgia syndrome (EMS), a disease that occurred in various parts of the United States in 1989, with a view to determining its cause. We speculated that adrenal dysfunction might have potentially contributed to the occurrence of EMS and studied the effects of adrenal dysfunction on the eosinophil count in peripheral blood by using rats and mice whose adrenals had been excised or that had been metyrapone-treated, and giving them L-tryptophan. As a result, a significant increase in the eosinophil count was observed in both animal species. The results suggest that EMS may have been caused, not by L-tryptophan alone, but by the combined effects of adrenal dysfunction and L-tryptophan ingestion.

The effects of drugs on Sephadex-induced eosinophilia and lung hyper-responsiveness in the rat

1. Rats given an intravenous injection of Sephadex particles (0.5 mg of G200 in 1 ml of saline) on days 0, 2 and 5 had a blood eosinophilia which was maximal on day 7. 2. On day 7, broncho-alveolar lavage (BAL) fluids taken from the rats contained an increased number of eosinophils and fewer mononuclear cells but there was no change in the small number of neutrophils. In addition the rats were hyper-sensitive to the increase in resistance to artificial respiration produced by 5-hydroxytryptamine (5-HT), given intravenously, with a shift to the left of the log dose-response curve. Lung parenchymal strips, taken from the rats on days 6, 7 and 8, were hyper-reactive to 5-HT with an increase in slope of the log dose-response curve. 3. Compounds with a wide variety of activities were evaluated for their effects on the blood eosinophilia on day 7 when given before each injection of Sephadex. The eosinophilia was reduced by glucocorticosteroids, beta-adrenoceptor agonists, aminophylline, dapsone and phenidone. 4. Dexamethasone, isoprenaline, dapsone and phenidone at doses that reduced the blood eosinophilia also reduced the changes in number of leucocytes in the BAL fluids and the hyper-responsiveness to 5-HT in vivo and in vitro, except that the effects of dapsone on the hyper-sensitivity to 5-HT in vivo did not reach significance. Aminophylline was the least effective of the drugs at reducing the blood eosinophilia and its effects on the other changes did not reach significance. Sodium cromoglycate reduced the BAL eosinophilia but had no effect on the other changes produced by Sephadex. 5. The correlation coefficients between blood eosinophil numbers and reactivity to 5-HT in vitro and sensitivity in vivo were r = 0.76, (n = 88; P < 0.001) and r = 0.53, (n = 61; P < 0.001) respectively. 6. Doses of dexamethasone, isoprenaline, dapsone and phenidone that reduced the blood eosinophilia when given before each injection of Sephadex were inactive when given up to 8 h after the Sephadex. 7. These data show an association between blood eosinophilia and hyper-responsiveness of the lung. The blood eosinophilia in the rats was triggered within the first few hours of injecting the Sephadex and drugs have been identified which inhibit this trigger.

Eosinophilic inflammation in asthma

BACKGROUND AND METHODS

The importance of eosinophils in the pathogenesis of bronchial asthma is not established. In an attempt to evaluate the role of eosinophilic inflammation in asthma, we compared 10 normal subjects with 43 patients with chronic asthma, 19 of whom had severe disease as assessed by a clinical scoring method described by Aas and by pulmonary-function tests. Eosinophils were counted in peripheral blood and bronchoalveolar-lavage fluid, and in biopsy specimens obtained from the patients and post mortem from 8 subjects without asthma, but not from the 10 normal controls. Eosinophil cationic protein was titrated by radioimmunoassay in the bronchoalveolar-lavage fluid from all subjects and studied by immunohistochemistry in the biopsy specimens.

RESULTS

There was a significant increase in the number of peripheral-blood eosinophils in the patients that was correlated with the clinical severity of asthma (P less than 0.001) and pulmonary function (P less than 0.03). Levels of eosinophils and eosinophil cationic protein were increased in the bronchoalveolar-lavage fluid from the patients and were also correlated with the severity of asthma (P less than 0.001 and P less than 0.002, respectively). Hematoxylin-eosin staining of bronchial-biopsy specimens showed that intraepithelial eosinophils were present only in patients with asthma. Immunohistochemical analysis of eosinophil cationic protein revealed that normal subjects had only a few nondegranulated eosinophils deep in the submucosa, whereas all the patients had degranulated eosinophils beneath the basement membrane and among epithelial cells. In some patients there was a relation between the presence of degranulated eosinophils and epithelial damage.

CONCLUSIONS

Eosinophilic inflammation of the airways is correlated with the severity of asthma. These cells are likely to play a part in the epithelial damage seen in this disease.

Evaluation of beta-adrenergic function in normal and asthmatic children

Low levels of serum glucose have been observed in atopic individuals after a subcutaneous injection of epinephrine. This less than normal hyperglycemia could be evidence of partial beta-adrenergic blockade in atopy. We compared the basal values of glucose with those obtained after 30 and 60 minutes of a subcutaneous injection of epinephrine 1/1000 (0.006 ml/kg; maximum of 0.3 ml) in normal and atopic asthmatic children (mild, moderate, and severe). The glucose-oxidase method was used for the determination of glucose levels in peripheral blood. Glucose serum levels in normal children were significantly higher at 30 and 60 minutes compared with basal values. In patients with mild and moderate asthma, significantly higher values were observed only at 30 minutes. In severe asthmatics, the glucose levels at 30 minutes were not different from the basal values, but higher than those observed at 60 minutes. Comparison among the four groups showed significant differences between the nonatopic normal children and the severe asthmatic children at 30 and 60 minutes. The moderate asthmatic children showed significantly lower levels when compared with nonatopic normal children at 30 minutes.

Age-dependency of alpha- and beta-adrenoceptors on thrombocytes and lymphocytes of asthmatic and nonasthmatic children

Among the possible mechanisms which may cause wheezing or asthmatic episodes a genetically determined beta-adrenoceptor blockade and a hyperresponsiveness of alpha-adrenoceptors has been postulated. Evidence to support this hypothesis stems from an increased bronchial sensitivity to beta-blockers, a reduced formation of cyclic AMP in response to beta-adrenergic stimulation and enhanced alpha-adrenergic responses in asthmatic subjects. The recent development of techniques for measuring the specific, high-affinity binding of radiolabeled alpha- and beta-adrenergic antagonists made it possible to study alpha- and beta-adrenoceptors in vitro. Based upon the assumption that a change in the number and/or affinity of adrenergic receptors might be a general phenomenon, we have performed alpha- and beta-receptor binding studies on lymphocytes and platelets from wheezing infants and asthmatic children as well as of infants, children, and adults not suffering from these diseases. Using 125[I]-cyanopindolol (ICYP) and 3[H]-yohimbine (HYOH) as highly specific ligands for alpha- and beta-adrenoceptors, the following results were obtained: Lymphocytes and platelets from control subjects and asthmatics bound similar amounts of ICYP and HYOH and thus showed no differences either in the number or the affinity of alpha- and beta-adrenoceptors. Lymphocytes and platelets of wheezing and nonwheezing infants also bound the same amounts of the radioligands. In asthmatic children receiving 4 X 2 puffs salbutamol beta-adrenoceptors were down-regulated and this may mimic beta-adrenoceptor blockade. When subjects were divided into four categories according to age (0-5, 5-10, 10-20 years, adults) the number of beta-adrenoceptor binding sites showed an age-dependent increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of beta-adrenergic receptors on lymphocytes in normal subjects and asthmatics in relation to beta-adrenergic hyperglycaemic response and bronchial responsiveness

The numbers of beta-adrenergic receptors on lymphocytes in normal subjects and asthmatic patients were measured by the use of [125I]hydroxybenzylpindolol. The numbers of beta-adrenergic receptors per lymphocyte in normal subjects, drug-free asthmatics and patients taking beta-stimulants were 1146 +/- 98, 845 +/- 114 and 582 +/- 47 sites/cell (mean +/- SE), respectively. The differences were statistically significant (P less than 0.05) among these groups, while no statistically significant differences were found in dissociation constants. A 42% decrease in the number of beta-adrenergic receptors per lymphocyte after administration of 6 mg/day of terbutaline for 7 days was noted in four volunteers. There was significant correlation (r = 0.68, P less than 0.01) between the number of beta-adrenergic receptors per lymphocyte and the percentage increase in blood sugar 20 min after subcutaneous injection of 4 micrograms/kg epinephrine. There was also significant correlation (r = 0.78, P less than 0.005) between the number of beta-adrenergic receptors per lymphocyte and the respiratory threshold for acetylcholine. These results suggest that beta-blockade and bronchial hypersensitivity in asthmatic patients may in part be due to a decreased number of beta-adrenergic receptors.

Central dopamine receptors regulate blood eosinophilia in the rat

Dopaminergic agents, dopa and apomorphine, affected biphasically the blood eosinophil count in the rat: low doses of the drug elevated, while high doses lowered it. The response to a high dose of dopa was retained in rats pretreated with an inhibitor of dopamine-beta-hydroxylase, U 10, 157, but prevented by a centrally acting dopa decarboxylase inhibitor, NSD 1015. This indicates that the eosinopenia observed after large doses of dopa is due to the action of dopamine formed from the precursor. As intracerebroventricular injections of Ldopa also produce eosinopenia, the central site of dopamine action is indicated. The eosinopenic response to apomorphine was antagonized by a dopamine receptor blocking agent, haloperidol. This indicates that some central dopamine receptors are involved in the regulation of the eosinophil count in circulating blood. The hypophysis seems to play a crucial role in the phenomenon observed, as no eosinopenia was produced by dopa in hypophysectomized rats.

Impaired responses of growth hormone and blood eosinophils to L-dopa in atopy

In order to assess whether response to the natural precursor of catecholamines in the nervous system is impaired in atopy, 500 mg L-dopa was administered to 13 atopic patients with bronchial asthma or hay fever and 13 sex-and-age-matched control subjects. The blood eosinophil count and growth hormone (GH) levels were then determined periodically over a 4-h period. The eosinophil count rose significantly 30 and 60 min after L-dopa in healthy subjects, but not in the atopic patients. The mean rise in GH 30 and 60 min after L-dopa was significantly lower in atopic patients as compared with controls. Injection of apomorphine 0.75 mg elicited increase in GH in nine of the 10 control subjects, but only in six of the 11 atopic patients. These results indicate that central dopaminergic stimulation is often impaired in patients with atopy. In testing GH release, atopy should be considered among the causes of failure to respond.

Comparison of cyclic adenosine monophosphate response of lymphocytes in normal and asthmatic subjects to norepinephrine and salbutamol

Reduced response of beta adrenergic receptors, especially beta-2 receptors, has been suggested as a contributing factor in the etiology of asthma. Cyclic adenosine monophosphate (AMP) production in lymphocytes after exposure to 10(-3) M salbutamol, predominantly a beta-2 receptor stimulant, was significantly less in asthmatic subjects than in normal subjects, while there was no significant difference in cyclic AMP response to 10(-3) M norepinephrine, predominantly a beta-1 receptor stimulant. Both drugs evoked the maximum response at 10(-3) M. The cyclic AMP response to salbutamol of 5 asthmatic subjects being treated with steroids was diminished significantly compared with that of 7 patients not treated with steroids; however, the response to norepinephrine was similar in both groups. The degree of the abnormality in the beta-2 receptor response seems to be related to the severity of the asthma.

Histamine hypersensitivity in mice induced by Bordetella pertussis or pharmacologic beta adrenergic blockade. Effects of adrenergic, cholinergic, and other drugs

The effects of prostaglandin E1, E2, F2alpha (PGE2 PGF2alpha), isoproterenol, epinephrine, norepinephrine, salbutamol, practolol, atropine, aminophylline, and corticosterone on the hypersensitivity to anaphylaxis, histamine, and serotonin in Bordetella pertussis-treated mice and propranolol-treated mice were investigated. Female HLA-SW (ICR) mice, 27-29 gm, were injected with pertussis vaccine intravenously 4 days before challenge with antigen, histamine, or serotonin. Alternatively, instead of pertussis vaccine, propranolol was injected intraperitoneally 45 min before histamine challenge. Test drugs were administered intraperitoneally 15 min before challenge. PGE1 and PGE2 at a narrow range of between 10 and 100 mug and epinephrine at 100 mug protected both pertussis- and propranolol-treated mice. Isoproterenol (25 mug) and aminophilline (800 mug) protected beta-blocked mice, but did not protect pertussis-treated mice even with very high doses (1,000 and 3,2000 mug, respectively), although salbutamol (500 mug) did. PGF2alpha, norepinephrine, and atropine were not protective at all. Practolol, a beta 1-blocker, given intraperitoneally 30 min before histamine neither sensitized normal mice nor changed the effect of isoproterenol or salbutamol in pertussis-treated mice. Corticosterone 10 mg/kg reduced the number of deaths from histamine in beta-blocked mice, but not in pertussis-treated mice. The protective effect is discussed in connection with probable effects of the drugs on intracellular cyclic adenosine monophosphate (cAMP) levels.

Subsensitivity to epinephrine following the administration of epinephrine and ephedrine to normal individuals

Cardiovascular and metabolic responses to exercise and consecutive epinephrine infusions 24 hours apart were measured in 7 normal individuals before and following a week's administration of ephedrine sulfate. There was evidence of less beta adrenergic response to the second control epinephrine infusion compared to the first control infusion, and the depression of the rise in blood lactate was significantly different. A week of ephedrine produced more profound depression of the beta adrenergic responses to epinephrine with significant differences in the rise in blood glucose and lactate, and the pulse and blood pressure responses. Furthermore, these same responses remained significantly altered when a second epinephrine infusion was performed 36 hours following the last dose of ephedrine. The alterations in the response to epinephrine induced by ephedrine are consistent with the concept of effector cell "subsensitivity," an adaptive response to prolonged excessive stimulation.

Greater frequency of viral respiratory infections in asthmatic children as compared with their nonasthmatic siblings

A longitudinal clincal and microbiologic surveillance was conducted from October to May, 1971-72, on 16 children with infectious asthma and 15 of their nonasthmatic siblings. Asthmatic children experienced a significantly greater frequency of viral respiratory infections than did nonasthmatic ones (5.1 vs. 3.8 per subject). This increased incidence appeared to be largely the result of a greater number of rhinovirus infections. While respiratory infections of identical etiology that occurred concurrently in an asthmatic and his sibling were equivalent in severity, illnesses were longer (but not significantly so) in asthmatic children.