Intimal enlargement of pulmonary arteries is an early change in chronic obstructive pulmonary disease (COPD). The cellular and extracellular components that are involved in this enlargement are unknown. The present study was designed to characterize the structural changes occurring in pulmonary muscular arteries in the initial disease stages.Lung specimens from patients with moderate COPD (n=8; forced expiratory volume in one second (FEV1), 66¡10% predicted) and smokers without airflow obstruction (n=7; FEV1, 86¡6% pred), were investigated by histochemistry to characterize extracellular matrix proteins and by immunohistochemistry to identify intrinsic cells of the vascular wall.In both COPD patients and smokers, the majority of cells present in the enlarged intimas were stained by specific smooth muscle cell (SMC) markers. No staining with endothelial or fibroblast markers was shown. A proportion of SMCs did not stain with desmin, suggesting cellular heterogeneity in this population. Elastin was the most abundant extracellular matrix protein and collagen was seen in a lower proportion. The amount of collagen was related to the intimal thickness (pv0.001).The findings demonstrated smooth muscle cell proliferation, as well as elastin and collagen deposition, in the thickened intimas of pulmonary arteries in moderate chronic obstructive pulmonary disease patients and smokers, suggesting that these abnormalities may originate at an early stage in cigarette smoke-induced respiratory disease.

Background-A study was undertaken to assess the diagnostic value of diVerent clinical criteria and the impact of microbiological testing on the accuracy of clinical diagnosis of suspected ventilator associated pneumonia (VAP). Methods-Twenty five deceased mechanically ventilated patients were studied prospectively. Immediately after death, multiple bilateral lung biopsy specimens (16 specimens/patient) were obtained for histological examination and quantitative lung cultures. The presence of both histological pneumonia and positive lung cultures was used as a reference test. Results-The presence of infiltrates on the chest radiograph and two of three clinical criteria (leucocytosis, purulent secretions, fever) had a sensitivity of 69% and a specificity of 75%; the corresponding numbers for the clinical pulmonary infection score (CPIS) were 77% and 42%. Non-invasive as well as invasive sampling techniques had comparable values. The combination of all techniques achieved a sensitivity of 85% and a specificity of 50%, and these values remained virtually unchanged despite the presence of previous treatment with antibiotics. When microbiological results were added to clinical criteria, adequate diagnoses originating from microbiological results which might have corrected false positive and false negative clinical judgements (n = 5) were countered by a similar proportion of inadequate diagnoses (n = 6). Conclusions-Clinical

To investigate whether endothelial dysfunction of pulmonary arteries (PA) is present in patients with mild chronic obstructive pulmonary disease (COPD) and to what extent it is related to the morphological abnormalities of PA, we studied 41 patients who underwent lung resection. Patients were divided into the following groups: nonsmokers ( n = 7), smokers with normal lung function ( n = 13), and COPD ( n = 21). Endothelium-dependent relaxation mediated by nitric oxide was evaluated in vitro in PA rings exposed to cumulative concentrations of acetylcholine (ACh) and ADP. Structural abnormalities of PA were assessed morphometrically. PA of COPD patients developed lower maximal relaxation in response to ADP than both nonsmokers and smokers ( P < 0.05 each) and a trend to reduced relaxation in response to ACh ( P = 0.08). Maximal relaxation to ADP correlated with the degree of airflow obstruction ( r = 0.48, P < 0.01). Morphometrical analysis of PA revealed thicker intimas, especially in small arteries, in both smokers and COPD compared with nonsmokers ( P < 0.05 each). We conclude that endothelial dysfunction of PA is already present in patients with mild COPD. In these patients, as well as in smokers with normal lung function, small arteries show thickened intimas, suggesting that tobacco consumption may play a critical role in the pathogenesis of pulmonary vascular abnormalities in COPD.

Endothelial dysfunction and intimal thickening have been shown in pulmonary arteries (PA) of patients with mild chronic obstructive pulmonary disease (COPD). To investigate whether an inflammatory process related to tobacco smoking might be involved in the development of pulmonary vascular abnormalities in COPD, we characterized the inflammatory cell infiltrate and the endothelium-dependent relaxation in PA of 39 patients who underwent lung resection, divided into three groups: "nonsmokers" (n ϭ 7); "smokers," with normal lung function (n ϭ 12); and "COPD" (n ϭ 20). Endothelium-dependent relaxation was assessed in vitro by exposing PA rings to adenosine diphosphate (ADP). Inflammatory cell types were identified by immunohistochemistry. PA of COPD patients Structural and functional abnormalities of the pulmonary circulation are common features in the wide spectrum of chronic obstructive pulmonary disease (COPD). Dysfunction of the pulmonary endothelium, which is associated with an impaired release of endothelium-derived nitric oxide (NO), may play a critical role in the remodeling of pulmonary vessels in COPD. Endothelial dysfunction in pulmonary arteries was initially shown in end-stage COPD patients undergoing lung transplantation by Dinh-Xuan and coworkers (1). In a recent study we observed that endothelial dysfunction may also be present in pulmonary arteries of patients with mild COPD (2). However, whereas in end-stage COPD chronic severe hypoxemia may account for the impairment of the endothelial function (1), the mechanisms of such an impairment in patients with milder degrees of disease, who are not hypoxemic, are unknown.Several studies performed in lungs of patients with mild COPD have shown apparent abnormalities in the structure of the pulmonary muscular arteries, in most cases consisting of the thickening of the intimal layer (3-5). Interestingly, the intensity of the intimal thickening has been shown to correlate with the severity of the inflammatory infiltrate in small airways (5, 6), suggesting that an inflammatory process might also account for the structural abnormalities of the pulmonary artery wall. Indeed, inflammation has been shown to be involved in the pathogenesis of some forms of pulmonary hypertension (7) and also in the remodeling of systemic vessels (8). Accordingly, we hypothesized that the structural abnormalities and the endothelial dysfunction shown in pulmonary arteries of patients with mild COPD could be related to an inflammatory process.Cigarette smoking causes an inflammatory reaction in the airways of patients with COPD. Whereas in both asymptomatic smokers and patients with COPD the nature and characteristics of the inflammatory reaction in central and peripheral airways (9-14), as well as in alveolar septa (15), have been thoroughly evaluated, little is known about the degree, nature, and evolution of the inflammatory infiltrate in pulmonary arteries of COPD patients.The present study, results of which have been given in abstract form (16), was therefore addressed to inves...