Chronic sinusitis in severe asthma is related to sputum eosinophilia

Matrix metalloproteinases in the pathogenesis of asthma and COPD: implications for therapy

While asthma is an inflammatory disorder of the airways involving mediators released from mast cells and eosinophils, inflammation alone is insufficient to explain the chronic nature of the disease. Recent progress in the understanding of disease pathogenesis has revealed that airway remodeling, which is at least in part due to an excess of extracellular matrix (ECM) deposition in the airway wall, plays a significant role in airflow obstruction. Matrix metalloproteinases (MMPs) have been suggested to be the major proteolytic enzymes to induce airway remodeling in asthma and COPD. It has been widely accepted that different inflammatory processes are involved in asthma and COPD with different inflammatory cells, mediators, and responses to treatments. Despite these different processes, airflow obstruction and airway remodeling characterize these two diseases. MMP-2 and -9 have been reported to be involved in the pathogenesis of airway remodeling in both diseases and MMP-12, in addition to these MMPs, in the pathogenesis of COPD. In this review, we discuss the current views on the role of MMPs in the pathogenesis of bronchial asthma and COPD. Anti-MMP therapy could theoretically be useful to prevent airway remodeling in asthma and COPD. However, to date no clinical data are available regarding the efficacy of anti-MMP therapies in the treatment of patients with asthma and COPD.

Leukotriene receptors in rhinitis and sinusitis

Cysteinyl leukotrienes (CysLTs) mediate their biologic activities through interactions with the CysLT1 and CysLT2 receptors. CysLT1 receptors are prominently expressed on smooth muscle cells and lung fibroblasts, whereas CysLT2 receptors are expressed on heart Purkinje fiber cells, adrenal chromaffin cells, and endothelial cells. Both receptors are expressed on eosinophils and mast cells, but CysLT1 receptors alone are on neutrophils. Antigen-presenting cells more prominently express the type 2 receptor. CysLT1 receptors are uniquely important for bronchospasm, whereas CysLT2 receptors can stimulate endothelial cell adherence, myofibroblast proliferation, and chemokine production by mast cells. Comprehensive inhibition of the proinflammatory activities of CysLTs might require either combination CysLT1 and CysLT2 receptor antagonists or inhibitors of the CysLT synthesis pathway.

"Refractory" eosinophilic airway inflammation in severe asthma: effect of parenteral corticosteroids

It has been suggested that patients with refractory eosinophilic airway inflammation represent a separate "eosinophilic" asthma phenotype associated with increased morbidity and a poor prognosis. To investigate whether persistent eosinophilia in these patients is a fixed feature or can still be modified by treatment, we investigated the effect of high-dose intramuscular corticosteroids on eosinophils in induced sputum. Twenty-two patients with stable severe asthma (15 women, aged 21-73 years) participated in this double-blind, placebo-controlled study. All were using inhaled corticosteroids (> or = 1,600 microg/day) or chronic oral prednisone. They were included if the percentage of eosinophils in induced sputum was above the upper limit of normal (> or = 2%). Two weeks after treatment with triamcinolone, but not placebo, sputum eosinophils almost completely disappeared from a median of 12.6-0.2% (p < 0.001). In 82% of patients, no eosinophils could be observed at all. In addition, the rescue medication score decreased from 1.4 to 0.8 (p = 0.01), and FEV1 improved from a median of 73.8-88.3% predicted (p = 0.001). We conclude that persistent sputum eosinophilia despite extensive antiasthma treatment is not a refractory phenomenon but is still sensitive to high-dose systemic corticosteroids. This implies that these patients with severe asthma need additional or alternative antiinflammatory treatment to combat the eosinophilia and associated poor prognosis.

Characterization of interleukin-4-stimulated nasal polyp fibroblasts

Chronic hyperplastic eosinophilic sinusitis is an inflammatory disease that results in the accumulation of eosinophils, fibroblasts, mast cells, and goblet cells at the site of injury. A common feature of this disease is the presence of nasal polyposis (NP). The current studies were designed to assess the contribution of interleukin (IL)-4 to fibroblast-mediated inflammation in chronic hyperplastic eosinophilic sinusitis/NP. In addition, we hypothesized that cysteinyl leukotrienes (CysLT) may directly influence fibroblast-mediated fibrotic and remodeling pathways in this disorder. Fibroblasts were isolated from NP tissue. All fibroblast lines expressed the IL-4 receptor. IL-4 induced changes in mRNA and protein expression of fibrotic (transforming growth factor-beta1 and -beta2) and inflammatory cytokines and chemokines (IL-6 and CCL11) by fibroblasts as measured by semiquantitative and quantitative polymerase chain reaction, RNase protection assay, and enzyme-linked immunosorbent assay. The expression of CysLT and other proinflammatory lipid receptors on fibroblasts was evaluated. CysLT1 and CysLT2 receptors were not expressed on fibroblasts; however, LPA(1) receptor was constitutively expressed and LPA(2) receptor expression was upregulated by IL-4. The metabolic cascade involved in CysLT synthesis was not expressed in fibroblasts and could not be induced by IL-4 treatment.

Allergic rhinitis: systemic inflammation and implications for management

Allergic rhinitis triggers a systemic increase of inflammation. Within minutes of allergen exposure, immune cells release histamine, proteases, cysteinyl leukotrienes, prostaglandins, and cytokines. Some produce the early symptoms, while others augment the production, systemic circulation, and subsequent infiltration of the nasal mucosa with inflammatory cells that sustain the symptoms. Systemic circulation of inflammatory cells permits their infiltration into other tissues where chemoattractant and adhesion molecules already exist. Consequently, allergic rhinitis is linked to comorbid conditions: asthma, chronic hyperplastic eosinophilic sinusitis, nasal polyposis, and serous otitis media. Effective therapy should be directed at underlying inflammation and its systemic manifestations. It should improve the rhinitis and the comorbid conditions. Antihistamines relieve early symptoms by blocking basophil- and mast cell-generated histamine, but they do not significantly influence the pro-inflammatory loop. They are often little better than placebo. Oral corticosteroids provide the systemic anti-inflammatory efficacy, but their toxicity precludes such an approach. Intranasal corticosteroids effectively target the local inflammatory processes of rhinitis, reducing local inflammatory cells within the nares, but they do not directly access tissues involved in the comorbid conditions. Leukotriene modifiers have both systemic anti-inflammatory effects and an acceptable safety profile.

The impact of rhinosinusitis on asthma

The nasal cavity, paranasal sinuses, and lungs are considered separate organs of the respiratory tract. However, a growing body of evidence links the upper and lower airways. For example, the coexistence and impact of allergic and nonallergic rhinitis on asthma is now documented. In addition, inflammation of the nose (rhinitis) commonly is associated with inflammation of sinuses (sinusitis), as reflected in the term rhinosinusitis. In this paper, we review the impact of rhinosinusitis on asthma as it relates to the links between allergic and nonallergic rhinitis and asthma; viral upper respiratory tract infections and asthma; allergic and nonallergic infectious/inflammatory rhinosinusitis and allergic and nonallergic hyperplastic rhinosinusitis and asthma; and the aspirin-exacerbated respiratory disease syndrome and asthma.

Nasal involvement in allergic asthma

Even since the late 19th century, a relationship has been suspected between upper airway disease and the subsequent development or aggravation of asthma symptoms. To date, it has been generally accepted that pathologic conditions of the upper airways, e.g. allergic rhinitis, chronic sinusitis and nasal polyposis, may influence the lower airways. However, the mechanisms underlying this relationship were, for a long time, poorly understood. Recently, evidence has been accumulating which indicates a systemic connection as one of the responsible mechanisms in nasobronchial crosstalk. In this review, the pathophysiologic and immunologic aspects of the interaction between upper and lower airways will be discussed.

Links between rhinitis and asthma

There is compelling evidence of a close relationship between the upper and lower airways in asthma and rhinitis. Rhinitis is present in the majority of patients with asthma, and a significant minority of patients with rhinitis have concomitant asthma. Similarities between the two conditions occur in the nature of the inflammation present in the target tissues. A common initiating step in the inflammatory process of allergic airways disease is the presence of immunoglobulin E providing an adaptor molecule between the offending allergen and inflammatory cell activation and mediator release. Differences in the two conditions arise largely from the structural differences between the nose and the lungs. In an asthmatic, concomitant allergic rhinitis increases healthcare costs and further impairs quality of life. The presence of rhinitis should always be investigated in children and young adults with asthma. Subjects with allergic rhinitis have an increased risk of developing asthma and may form a suitable population for secondary intervention to interrupt the 'allergic march'.

The role of allergy in chronic rhinosinusitis

Issues surrounding the cause and pathogenesis of chronic rhinosinusitis (CRS) remain controversial. Various models involving physiologic factors and anatomic obstruction have been offered to explain the pathogenesis of this common disease. More recently, the role of chronic inflammatory processes has been demonstrated. These findings may modify the current paradigm of this disease and transform the diagnosis and management of patients with CRS. This review focuses on the role of allergy and inflammation in the pathogenesis of CRS.

The link between upper and lower respiratory disease

The upper and lower airways are connected anatomically, physiologically, and immunologically. Epidemiologic studies provide strong evidence of associated dysfunction. Therapeutic modalities with indications for treatment of one portion of the airway are frequently used for the other. These include antihistamines, inhaled or nasal steroids, cromolyns, and most recently leukotriene receptor antagonists. Studies of the upper airway show that upper airway impairment with allergic rhinitis affects the lower airway and that pharmacological treatment of allergic rhinitis can prevent seasonal asthma. Recently, single-agent allergy sensitization has been shown to prevent the development of asthma. Conflicting data exist regarding the affect of sinus surgery on asthma severity. This review is intended to provide an update of our knowledge of the upper and lower airway connection, highlighting articles published within the last year.

The IL1A genotype is associated with nasal polyposis in asthmatic adults

BACKGROUND

Nasal polyposis (NP) is a chronic inflammatory disease often found coexisting with asthma. As this disorder tends to cluster in families, a genetic predisposition has been suggested. Interleukin-1 (IL-1) has been proposed to play a role in the pathogenesis of NP.

METHODS

We analysed the single G-to-T base exchange polymorphism in exon 5 at +4845 of the gene encoding IL-1alpha (IL1A) and the C-to-T base exchange polymorphism at -511 of the gene encoding IL-1beta (IL1B) in a population-based sample of adult asthma patients (n = 245). The data were assessed for correlation with data on history of NP and other phenotype-related characteristics.

RESULTS

The prevalence of NP in our study group was 14.3%. The distribution of the IL1A genotype differed significantly between asthmatics with and without NP (P = 0.005). The risk of NP was markedly increased in allele G homozygous subjects (OR = 2.73; 95%CI = 1.40-5.32). In the case of IL1B we found no significant associations. Asthmatics with NP had more symptoms than others, but lung function and blood eosinophil counts were similar.

CONCLUSIONS

Our study demonstrates an association of IL1A with NP inasthmatic patients and addresses the role of IL-1alpha as an inflammatory modulator in the pathogenesis of this disease.

Advances in upper airway diseases and allergen immunotherapy

Epidemiologic studies continue to find an increased prevalence of rhinitis, asthma, and atopy in more westernized countries. Both allergic and nonallergic rhinitis are risk factors for development of asthma, particularly in adulthood. In patients who have both asthma and rhinitis, treatment of the latter decreases the likelihood of emergency department visits or hospitalization for asthma. The protective effect of intranasal cortico-steroids is much greater than that of antihistamines. This mirrors the effect on rhinitis symptoms, in which nasal corticosteroids are much more effective than antihistamines, leukotriene receptor antagonists, or the combination of both. In patients with severe asthma, sinus mucosal thickening on computed tomography (CT) correlates with the severity of lower airway disease indicated by sputum eosinophilia, exhaled nitrous oxide (NO), functional residual capacity, and diffusing capacity. Preseasonal specific immunotherapy (SIT) is less effective, but additive to treatment with omalizumab. It is also somewhat less effective in reducing nasal symptoms than nasal corticosteroids; however, it is superior to them for reducing lower airway inflammation. SIT in children with only allergic rhinitis reduces both the incidence of asthma and bronchial hyperresponsiveness to methacholine. High-dose sublingual immunotherapy appears to be safe and effective, but less effective than injection immunotherapy. It is not clear that there are cost savings with sublingual immunotherapy, as home administration savings may be offset by the much larger amount of allergen extracts required. New approaches to allergen immunotherapy, designed to increase efficacy and safety, include conjugation of allergens to immunostimulatory sequences and encapsulation in liposomes. Cross-reactivity between inhalants and foods demonstrated by skin prick tests is more predictive of clinically important sensitivity than is that demonstrated by RAST testing. The latter, because of cross-reacting profilins, is often clinically irrelevant.

Sinus computed tomography scan and markers of inflammation in vocal cord dysfunction and asthma

BACKGROUND

The inappropriate closure of the vocal cords is characteristic of vocal cord dysfunction (VCD). These patients present with wheezing and frequently receive a misdiagnosis of asthma.

OBJECTIVE

To demonstrate the ability of computed tomography (CT) scored for the presence and extent of sinus disease and markers of inflammation to distinguish patients with VCD from patients with asthma.

METHODS

Comparisons of 13 patients with VCD were made to 77 patients presenting to the emergency room with acute asthma, 31 non-acute asthmatic patients, and 65 nonasthmatic controls. Evaluation consisted of exhaled nitric oxide gas (eNO), circulating eosinophils, and total serum immunoglobulin (Ig)E, as well as the sinus CT scan.

RESULTS

Extensive sinus CT changes were present in 23 of 74 acute asthmatic patients, 5 of 29 non-acute asthmatic patients, and 2 of 59 nonasthmatic controls. In addition, absolute eosinophil counts, eNO, and total IgE were significantly elevated among the asthmatic patients. Sinus symptoms reported by questionnaire did not predict sinus CT findings. Among the patients with VCD, none had extensive sinus disease. They also had normal eNO, low IgE, and normal eosinophil count. Five of the patients presenting to the emergency room who were identified as acute asthmatic were identified with VCD by laryngoscopy and were all characterized by the absence of significant inflammation on their sinus CT scan, low IgE, and normal eosinophil count.

CONCLUSIONS

Among patients presenting with intermittent or reversible airway obstruction, patients with VCD can be distinguished from asthma by minimum or absence of inflammation in their sinuses as shown by CT scan. Clinical symptom scores are not predictive of presence or extent of sinus disease in most cases.

Cysteinyl leukotriene expression in chronic hyperplastic sinusitis-nasal polyposis: importance to eosinophilia and asthma

BACKGROUND

Chronic hyperplastic eosinophilic sinusitis (CHS) results from the unregulated proliferation of eosinophils, T(H)2-like lymphocytes, goblet cells, mast cells, and fibroblasts and is present in most patients with asthma. The frequent coexpression of these disorders and their shared pathophysiology suggests that these are similar disorders affecting the upper and lower airways.

OBJECTIVE

We evaluated the expression of cysteinyl leukotrienes (CysLTs) in sinus tissue from subjects with CHS compared with that seen in healthy sinus tissue.

METHODS

Nasal polyp and sinus tissue was evaluated from 58 individuals undergoing elective functional endoscopic sinus surgery. The diagnosis of CHS was demonstrated through the presence of eosinophilia and activated (EG2(+)) eosinophils, as determined by means of tissue immunohistochemistry. Data were compared with those from both nasal polyp tissue without eosinophilic inflammation and healthy control sinus tissue obtained from the sinus ostiomeatal complex at the time of surgery for unrelated disorders. CysLTs were quantified by means of ELISA in lipid-extracted tissue. Activation of the metabolic pathway leading to CysLT synthesis was demonstrated by ribonuclease protection. Subjects were genotyped for leukotriene C(4) (LTC(4)) synthase C-to-A promoter polymorphism.

RESULTS

CysLT concentrations were significantly higher in tissue obtained from subjects with CHS (776.7 +/- 201.9 pg/g tissue) compared with that seen in healthy sinus tissue (355.7 +/- 101.6 pg/g tissue, P <.03). CysLT concentrations within noneosinophilic nasal polyps (328.0 +/- 116.4 pg/g tissue) were similar to those in control tissue. The presence of CysLTs in CHS was associated with increased expression of LTC(4) synthase mRNA. The C-to-A promoter polymorphism was associated with trends toward the increased presence of CHS and CysLTs.

CONCLUSIONS

CHS is characterized by the increased presence of CysLTs when compared with concentrations seen in tissue from patients with chronic inflammatory sinusitis or healthy sinus tissue. These studies support the use of LT modifiers as anti-inflammatory agents that might have clinical benefit in patients with these disorders.

Sinusitis update

PURPOSE OF REVIEW

Rhinosinusitis affects more than 10% of the US population. It results in high health care expenditure as well as decreased productivity through lost days of school or work. This review includes recent findings in diagnostics and pathophysiology, as well as recent advances in treatment.

RECENT FINDINGS

Parameters used in the diagnosis of rhinosinusitis include patient symptomatology, physical and endoscopic findings, computed tomography scan scores, and culture results. There has been poor correlation between patient symptoms and computed tomography scan scores, but middle meatal cultures have been shown to correlate well with ethmoid sinus cultures obtained from chronic rhinosinusitis patients. Chronic inflammation with a predominance of eosinophils and T lymphocytes in the tissues is being recognized as a hallmark of chronic rhinosinusitis, especially in patients with asthma or allergic rhinitis. Th2 cytokines are prominent in sinus tissues of patients with chronic rhinosinusitis and allergic rhinitis. While antibiotics are used with greater frequency in the treatment of acute and chronic rhinosinusitis, adjuvant therapies, such as intranasal steroids, might affect patient symptoms and curb disease recurrence.

SUMMARY

Clinical symptoms are important in making the diagnosis of rhinosinusitis and should be supported by objective findings on nasal endoscopy and, if necessary, computed tomography scans. The mainstay of treatment remains antibiotics, with a potential role for decongestants and intranasal steroids. The presence of chronic inflammation with a Th2 cytokine predominance in sinus tissues should be kept in mind, especially in patients with coexistent morbidities such as allergic rhinitis and asthma.