The increased susceptibility of the elderly to lower respiratory tract infection cannot be fully explained. Although mucociliary clearance, which is affected by ciliary beating and ultrastructure, plays a crucial role in the defense of the airways against inhaled microbes, little is known of the effects of aging on these parameters. We studied the nasal mucociliary clearance (NMCC) time, ciliary beat frequency, and ultrastructure of respiratory cilia in a cohort of healthy volunteers (age range 11 to 90 yr). Ciliary beat frequency of ciliated nasal epithelial cells was obtained via an established photometric method, and NMCC time was measured with the saccharine test. There was a correlation of ciliary beat frequency (r = -0.48, p = 0.0001) and NMCC time r = 0.64, p < 0.001) with increasing age. Transmission electron microscopy revealed an increase in the percent of subjects exhibiting microtubular disarrangement and single central microtubules with aging (p = 0.002 and p = 0.005, respectively). Subjects older than 40 yr of age had significantly slower ciliary beat frequency, higher percent of ciliary cross-sections displaying single tubules, and longer NMCC time than their younger counterparts (p < 0.05). These findings may help explain the frequent occurrence of respiratory infection in the elderly.

The progressive bronchial dilatation in bronchiectasis is likely to be the result of continued airway matrix destruction, although little is known about the role of neutrophil matrix metalloproteinases (MMPs) in this process.Immunohistochemistry has been used to investigate the expression and cellular localisation of MMP-8 and MMP-9 in bronchiectatic airways in vivo. Endobronchial biopsies were taken from 25 bronchiectatic patients, and from the right lower lobe in 14 control subjects. MMP-8, MMP-9, neutrophils and macrophages were stained with monoclonal antibodies and quantified as positive cell?mm -2 of the lamina propria by using an image analysis system.There were significantly higher densities of MMP-8 and MMP-9 positive cells in the lamina propria of bronchiectatic than control airways. In bronchiectatic airways, the densities of MMP-8 and MMP-9 positive cells correlated with each other and with neutrophil density, but not with macrophage density. In control airways, a significant correlation was found between MMP-8 with neutrophil and MMP-9 with macrophage densities.An overexpression of neutrophil matrix metalloproteinases in bronchiectatic airways could help explain the continuation of airway destruction in bronchiectasis. In view of the clinical availability of matrix metalloproteinase antagonists, the results presented here could have a significant impact on the development of novel therapies of this untreatable disease.

The airways of patients with bronchiectasis and cystic fibrosis are often chronically colonised by Pseudomonas aeruginosa (PA), which is virtually impossible to eradicate. Low-dose erythromycin (EM), for unknown mechanisms, is efficacious in bronchiectasis and diffuse panbronchiolitis.In this study, an in vitro model to investigate PA adherence to human type IV basement collagen was developed by using scanning electron microscopy (SEM). There were significantly less PA bacilli per 20 random SEM fields (4,0006) when PA was cultured in 0.05, 0.5 and 5 mg?mL -1 of EM compared with control (absence of EM). Adherence density (20 SEM fields?log -1 inocular size) for PA obtained from no EM (56.8¡43.16) was significantly higher than that obtained from 0.05, 0.5, and 5 mg?mL -1 EM (21.5¡17.56, 23.3¡16.65, and 21.4¡12.65 respectively). By using SEM it was found that PA, when incubated in EM (0.05, 0.5, 5 mg?mL -1 ) had a significant reduction in its diagonal length, radius, height, volume and surface area.It is possible, therefore, that these misshaped Pseudomonas aeruginosa bacilli are more susceptible to host defence mechanisms, while at the same time less adherent to the basement membrane of the airway in vivo. Therefore, this could help explain the clinical efficacy of low-dose erythromycin therapy on patients with Pseudomonas aeruginosa infection. Eur Respir J 2003; 21: 401-406.

Cilia are minute hairlike structures which sweep the respiratory tract clean by continuous beating. Ciliary dysfunction can occur which leads to development of bronchiectasis. We describe the clinical and investigation profiles of four patients who had early-onset severe and otherwise idiopathic bronchiectasis associated with a previously undescribed ciliary defect in which numerous cystlike structures are present within the ciliary shafts. The patients had otherwise normal ciliary microtubular ultrastructure and central microtubular orientation. Our newly described ciliary abnormality appears to be a primary defect and more systematic studies should be performed to evaluate this further.