Faculty Bibliography

Oral flora are frequently found in normal individuals' lungs without known harm. We hypothesize that a lung microbiome enriched by oral taxa would be associated with a higher degree of inflammation. We studied 29 asymptomatic subjects (9 nonsmokers and 20 smokers) with preserved lung function. Nasal bronchoscopy was performed with two separate bronchoscopes to retrieve supraglotic and lower airway samples. Bronchoalveolar lavage (BAL) cell count, BAL cytokines (Luminex), and exhaled nitric oxide defined pulmonary inflammation. Quantitative PCR measured 16S rRNA gene concentration and 454 sequences defined the microbiome. Supraglotic samples had the highest 16S rRNA concentration, BAL was intermediate, and saline used for the BAL had the lowest concentration. Nonsmokers and smokers were similar in BAL cell differential and lung microbiome. BAL samples segregated into two distinct groups that we called pneumotypes. Pneumotype background predominant taxa (pneumotypeBPT) was similar to the saline background in rDNA concentration or microbial community. Pneumotype supraglotic-characteristic taxa (pneumotypeSCT) has higher rDNA concentration and high relative abundance of SCT, such as Prevotella and Veillonella. PneumotypeSCT was associated with multiple measures of lung inflammation, including higher BAL neutrophils, IL-8, and levels of exhaled nitric oxide. PneumotypeSCT also had higher BAL lymphocytes and fractalkine, a chemokine that correlates with T helper type 17:T regulatory cell ratio in the BAL. These data suggest that a pneumotype with high relative abundance of supraglotic bacteria, such as Prevotella and Veillonella, is associated with increased innate and cellular inflammation.

Rationale: Macrolide antibiotics, specifically azithromycin, have antimicrobial and immunomodulatory effects and, despite not having proven effect on spirometry, have been shown to prevent exacerbations in patients with moderate to severe chronic obstructive disease (COPD). We have previously shown that in asymptomatic smokers with early emphysema identified by computed tomography, distal lung dysfunction is an early marker of subclinical lung inflammation. Thus, we hypothesized that in early emphysema, treatment with azithromycin will impact both distal lung function and biomarkers of airway inflammation. Methods: Emphysema subjects were identified from the NYU Lung Cancer Biomarker Center CT-Scan Screening Cohort. Ten subjects (7M/3F) with emphysema were enrolled for pulmonary function evaluation and research bronchoscopy pre and post eight weeks 250mg/day azithromycin therapy. Physiologic assessment included spirometry, plethysmography, and diffusing capacity. Distal lung function was assessed (pre and post bronchodilator) with impulse oscillometry (IOS). Pre and post bronchodilator exhaled nitric oxide (NO) was measured at variable flow rates to determine airway and alveolar NO concentration. Results: Subjects were 65+/-4 years age. All had history of smoking with emphysema identified on computed tomography. Subjects were asymptomatic with GOLD 0 spirometry in 9/10. Lung volumes (FRC, RV and TLC) and diffusing capacity were within normal limits in all subjects. In contrast, baseline IOS revealed abnormal resistance spectrum in 5/10 and abnormal reactance spectrum in 8/10, consistent with dysfunction in the distal lung. Post bronchodilator there was significant reduction in frequency dependence of resistance and in the reactance spectrum (R5-20 = 3.88 [3.39, 5.85] vs. 3.39 [3.26, 5.06] cmH2O/L/s, p = 0.022; X5 = -1.40 [-2.02, -1.01] vs. -1.03 [-1.47, -0.90] cmH2 O/L/s, p = 0.022; resonant frequency 16.2 [13.2, 20.1] vs. 13.6 [10.9, 16.2] Hz, p = 0.007). Following azithromycin therapy, IOS demonstrated no change in resistance; however, improved reactance was seen in 8 patients (p<0.04) and bronchodilator responsiveness was no longer present. Alveolar NO normalized in all subjects post azithromycin (baseline range 1.2-9.9 vs. 0-3.6 PPB post azithromycin, p=0.06 ) despite lack of change in airway NO. (Figure presented) Conclusions: In patients with early emphysema, azithromycin administration was associated with improved oscillometry reactance but not resistance parameters and improved alveolar rather than airway NO. These data support a beneficial effect of azithromycin on distal lung function and inflammation that may not be detected by routine tests

Rationale: Early COPD is characterized by inflammation leading to lung destruction. Recent data supports that enrichment of the lung microbiome with supraglottic characteristic taxa (SCT) is associated with inflammation. We hypothesize that in subjects with early COPD, areas at higher risk for microaspiration (right) or with greater degree of parenchymal abnormalities will be enriched with SCT or potential pathogenic taxa (PPT) compared to their contralateral lung segment. Methods: Subjects with early emphysema were enrolled for research bronchoscopy from the NYU/EDRN cohort. An independent radiologist semiquantitatively assessed all Chest CT scans: six-point score based on the presence of parenchymal damage in three zones (upper, middle, and lower). Broncho-alveolar lavages (BAL) were obtained from the right middle lobe and lingula segments. Sequencing 16S rDNA performed with 454 pyrosequence. Results: A total of 15 subjects with early COPD were studied. CT scans demonstrated n=7 with normal lower zones and n=8 with symmetrical or asymmetrical emphysema in the lower zones (p=ns). We used Wilcoxon paired comparisons to analyze the microbiome in areas of greater degree of parenchymal abnormalities (if asymmetric) or right compared to the contralateral lung segment. Data showed that the areas of greater abnormalities or right were associated with increased relative abundance (RA) of Haemophilus (RA 0.00170+/-0.002 vs. 0.00084+/-0.001, p=0.04), Neisseria (RA 0.0048+/-0.005 vs. 0.0023+/-0.003, p=0.028), Parvimonas (RA 0.017+/-0.003 vs. 0.0002+/-0.0008, p=0.05), and Serratia (RA 0.0122+/-0.02 vs. 0.0033+/-0.003, p=0.03) compared with the contralateral segment. Streptococcus appeared not to have a predilection for at-risk segments at the genus level. However, at the OTU level, Streptococcus mitis and Streptococcus pneumoniae species were higher in lung segments with more emphysema or right lung segments. Conclusions: Our data shows that areas of greater parenchymal damage or at higher risk for microaspiration (right) are enriched with potentially pathogenic taxa, such as Parvimonas, Neisseria, Haemophilus, Serratia, and Streptococcus. These taxa are known to be in high relative abundance in the oral and supraglottic region. Some of these taxa have been found to be at higher RA after viral infections, suggesting that enrichment of these low relative abundance taxa may play a critical role in disease. However, other supraglottic characteristic taxa such as Prevotella and Veillonella were not increased in these regions. These observations suggest a distinct selection pressure between the upper and lower airway microbiome