Effects of sodium cromoglycate on cytokine production following antigen stimulation of a passively sensitized human lung model

The effects of disodium cromoglycate on enhanced adherence of Haemophilus influenzae to A549 cells infected with respiratory syncytial virus

Nontypeable Haemophilus influenzae (NTHi) secondary infection often complicates respiratory syncytial virus (RSV) infections. Previous studies have revealed that RSV infections enhance NTHi adherence to airway epithelial cells. In this study, we investigated the effects of disodium cromoglycate (DSCG) and corticosteroids, which are frequently used for the treatment of wheezing often related to RSV infections, on the adherence of NTHi to RSV-infected A549 cells. DSCG inhibited enhanced adherence of NTHi to RSV-infected A549 cells, whereas dexamethasone (Dex) and fluticasone propionate (Fp) did not. DSCG suppressed the expression of ICAM-1, which is one of the NTHi receptors. Furthermore, DSCG exhibited an inhibitory effect on RSV infections. It is suggested that DSCG exerts an anti-RSV effect, and consequently attenuates the expression of NTHi receptors.

The new role of disodium cromoglycate in the treatment of adults with bronchial asthma

BACKGROUND

Viral infection of the respiratory tract in patients with asthma is one of the most frequent causes of exacerbation of asthmatic symptoms. Disodium cromoglycate (DSCG) is a commonly used anti-asthmatic medicine with many beneficial biochemical and physiological effects. The purpose of this study was to investigate the efficacy of DSCG against colds when used in clinical practice.

METHODS

A questionnaire survey to determine the efficacy of DSCG was undertaken in 220 adult patients with asthma (81 male, 139 female; mean age: 54.1 +/- 13.7 years and 60.1 +/- 12.7 years, respectively) from April to September 2004 at the Miyatake Asthma Clinic.

RESULTS

The duration of DSCG inhalation therapy was not less than 5 years in more than half of the patients. The mean daily DSCG dose at the time of the questionnaire survey was 40mg/day in over 50% of all patients. After DSCG was added to inhaled corticosteroid (ICS) combination therapy, 56.4% of the patients rated their condition as "improved", and 66.4% of the patients felt that the frequency of colds they had caught had decreased while DSCG was added to ICS.

CONCLUSIONS

DSCG inhalation therapy is a useful additional treatment following ICS to alleviate asthma symptoms, and to prevent colds in adult patients with asthma.

A model of allergen-driven human airway contraction: beta2 pathway dysfunction without cytokine involvement

BACKGROUND

In our previous in vitro model, allergen incubation of passively sensitized human airways reduced the response to salbutamol. However, whether cytokines play a role in this model is still unknown.

OBJECTIVE

To investigate interleukin 1beta and tumor necrosis factor a expression in allergen-challenged human airways.

METHODS

Nonasthmatic airways (n = 13) were passively sensitized by overnight atopic serum incubation and then challenged with allergen for 1 hour (n = 9). After repeated washouts, airways were immersed in physiologic salt solution for 6 hours and finally in formaldehyde for immunohistochemical studies. The effect of co-incubation in anti-interleukin 1beta and anti-tumor necrosis factor a specific neutralizing antibodies on salbutamol response was also studied (n = 4).

RESULTS

No differences were found among control, sensitized, and challenged rings in the number of inflammatory cells. The percentage of basement membrane covered by epithelium was similar in the different conditions. There was a higher percentage of degranulating to total mast cells in allergen-challenged rings than in sensitized rings (P < .001). A significant correlation was observed between allergen-induced contraction and mast cell degranulation (r = 0.88; P < .001). The sensitization procedure was validated by paired allergen-induced contractions. No expression of the 2 cytokines was detectable up to 6 hours after allergen challenge, and specific neutralizing antibodies did not attenuate the impaired response to salbutamol in allergen-challenged rings.

CONCLUSION

These data suggest that in our in vitro model of allergic inflammation, beta2 pathway dysfunction can occur without cytokine involvement, thus supporting previous results that suggest a role for leukotrienes.

Corticotropin-releasing hormone and brain mast cells regulate blood-brain-barrier permeability induced by acute stress

Stress activates the hypothalamic-pituitary-adrenal axis through release of corticotropin releasing hormone (CRH), leading to production of glucocorticoids that down-regulate immune responses. Acute stress, however, also has proinflammatory effects that seem to be mediated through the activation of mast cells. Stress and mast cells have been implicated in the pathophysiology of various inflammatory conditions, including some in the central nervous system, such as multiple sclerosis in which disruption of the blood-brain barrier (BBB) precedes clinical symptoms. We previously showed that acute restraint stress increases rat BBB permeability to intravenous 99Tc gluceptate and that administration of the "mast cell stabilizer" disodium cromoglycate (cromolyn) inhibits this effect. In this study, we show that the CRH-receptor antagonist Antalarmin blocks stress-induced 99Tc extravasation, whereas site-specific injection of CRH in the paraventricular nucleus (PVN) of the hypothalamus mimics acute stress. This latter effect is blocked by pretreatment of the PVN with cromolyn; moreover, restraint stress cannot disrupt the BBB in the diencephalon and cerebellum of W/W(v) mast cell-deficient mice. These results demonstrate that CRH and mast cells are involved in regulating BBB permeability and, possibly, brain inflammatory disorders exacerbated by acute stress.

The role of sodium cromolyn in treatment of paraquat-induced pulmonary fibrosis in rat

Paraquat is a non-selective herbicide which is widely used in agriculture. It has potential of producing pulmonary fibrosis. In this study the therapeutic effect of different doses of sodium cromolyn on the development of paraquat-induced pulmonary fibrosis was investigated. In order to produce lung fibrosis, rats were given single oral dose of paraquat (40 mg kg(-1)). Two groups of animals were nebulised with 6 or 8 mg day(-1) cromolyn (divided into two doses per day) 5 days prior and 2 weeks after paraquat treatment. Control animals were given equivalent volume of normal saline and treated with cromolyn similar to the test groups. Rats were killed at the end of treatment course and lung tissues were tested histologically and biochemically. Histological examination of paraquat-treated animals showed marked infiltration of inflammatory cells in the alveolar spaces, septal thickening and fibrosis. Lesions were evident in many places of sections. Sodium cromolyn could markedly reduce such damages in lung tissue. Lung weight, hydroxyproline and collagen content of lung tissues were elevated significantly (P < 0.05) in paraquat group compared with control group. In cromolyn-treated groups such factors were near to control value and were significantly lower than paraquat group (P < 0.05). Results of this study indicate that sodium cromolyn can decrease the fibrogenic effect of paraquat on lung. Such effect may be due to the stabilising of mast cells and inhibition of inflammatory mediators by sodium cromolyn.

Preoperative steroid therapy inhibits cytokine production in the lung parenchyma in asthmatic patients

OBJECTIVES

During or after surgery, asthma attacks due to airway hyperresponsiveness (AHR) are likely to occur in patients with bronchial asthma. Preoperative administration of corticosteroid for prevention of perioperative asthma attacks is useful. We examined the mechanism of prevention of perioperative asthma attacks by the preoperative administration of corticosteroid in vitro.

DESIGN

Five patients with asthma were treated with 20 mg of prednisolone orally for 2 preoperative days and 80 mg of methylprednisolone IV immediately before and after surgery. In another five patients without asthma, no steroids were administered. A noncarcinomatous part of the resected tissue from each patient with lung cancer was passively sensitized with the serum of an atopic patient. In the patients without asthma, the tissue was treated with or without dexamethasone, and then mite antigen was added.

MEASUREMENTS

The culture supernatant and lung tissue were recovered, and the supernatant was assayed for histamine, leukotriene E(4) (LTE(4)), interleukin (IL)-5, and tumor necrosis factor (TNF)-alpha. Degranulation of mast cells was measured by tryptase staining of the lung tissue, and the expression of messenger RNA (mRNA) of IL-5 and TNF-alpha was determined by the reverse transcriptase-polymerase chain reaction method.

RESULTS

While preoperative administration of corticosteroid did not suppress the release of histamine and LTE(4) from the lungs of asthmatic patients, it completely suppressed IL-5 and TNF-alpha production at the mRNA level. The same results were obtained in lung tissues of nonasthmatic patients treated in vitro with dexamethasone.

CONCLUSIONS

Our results suggest that corticosteroid treatment reduces AHR and prevents perioperative attacks of asthma primarily by suppressing the production of inflammatory cytokines.

Asthma

Asthma is an important and increasingly prevalent respiratory disease. Its proper diagnosis and treatment lie at the heart of improving asthma outcome. Unfortunately, asthma has many faces and is affected by many variables, many of them difficult to control. Like many chronic illnesses, asthma tends to affect the poor and less advantaged individuals in society. Heightened awareness among patients and physicians of the serious nature of the disease is needed to reduce the morbidity and mortality of asthma. Treatment clearly requires a multifaceted approach, including behavioral, environmental, social, and medical interventions, in which the National Asthma Education and Prevention Program guidelines provide a logical, step-wise, and effective approach.