Elevated substance P content in induced sputum from patients with asthma and patients with chronic bronchitis.

Abstract

In experimental studies, tachykinins, especially substance P (SP), cause many of the pathophysiological features of neurogenic inflammation. It is unclear whether these peptides are involved in human airway inflammation in diseases such as asthma and chronic bronchitis. To elucidate the relation between neurogenic inflammation and airway inflammatory diseases, we examined the SP concentration in sputum after hypertonic saline inhalation challenge in patients with asthma, patients with chronic bronchitis, and normal volunteers. SP concentration was measured by radioimmunoassay. The sputum SP concentration was significantly higher in patients with asthma (mean +/- SEM, 17.7 +/- 2.4 fmol/ml; p < 0.01) and patients with chronic bronchitis (25.6 +/- 5.5 fmol/ml; p < 0.01) than in normal volunteers (1.1 +/- 0.4 fmol/ml). In patients with asthma, the SP concentration was significantly related to the eosinophil cell count in induced sputum. In all subjects, the SP concentration in induced sputum correlated with FEV1/FVC. These data suggest that neurogenic inflammation may be involved in the airway inflammatory process and subsequent airway narrowing not only in asthma but also in chronic bronchitis.

Plasma Substance P Levels in Patients with Persistent Cough

“…We found no correlation between plasma SP levels and spirometric indices, which contradicts the findings of Tomaki et al [23], who found a negative correlation between sputum SP levels and FEV 1 /FVC in patients with classic asthma. This discrepancy might be attributed to the different sample sources and less prominent airflow obstruction in our patients (FEV1/FVC of 80.3% by average) compared with those of Tomaki et al [23] (71.3%).…”

“…Lee et al [10] found increased SP-immunoreactive nerve densities in patients with CVA but not in those with classic asthma. SP is associated with neurogenic inflammation and subsequent airflow obstruction in asthma [23,44]. We found no correlation between plasma SP levels and spirometric indices, which contradicts the findings of Tomaki et al [23], who found a negative correlation between sputum SP levels and FEV 1 /FVC in patients with classic asthma.…”

“…A correlation between sputum SP levels and sputum eosinophil count has been reported in asthma [23]. Since patients with CVA show evidence of airway inflammation with increased eosinophils [47] and since nonasthmatic cough might be associated with increased neutrophils [48], we evaluated the correlation between plasma SP levels and sputum counts of eosinophils and neutrophils in each patient group.…”

“…Therefore, SP might be differently involved in the mechanisms of both asthmatic and nonasthmatic cough. Indeed, SP contents in the nasal lavage fluid of patients with nonasthmatic cough are associated with increased cough sensitivity [11], whereas in asthma sputum levels of SP correlate with airflow obstruction [23]. …”

Substance P-Immunoreactive Nerves in Endobronchial Biopsies in Cough-Variant Asthma and Classic Asthma

“…With the use of immunohistochemical techniques, it has been demonstrated that the airways of asthmatics possess a greater number of SP-immunoreactive nerves than those of nonasthmatics [12]. In addition, it has been demonstrated that the SP content is elevated in induced sputum from patients with asthma [13]. However, immunohistochemical studies by other investigators in the airways of asthmatics have yielded conflicting results [14, 15, 16].…”