Filippo Andò

Anatomy and neuro-pathophysiology of the cough reflex arc.

Coughing is an important defensive reflex that occurs through the stimulation of a complex reflex arc. It accounts for a significant number of consultations both at the level of general practitioner and of respiratory specialists. In this review we first analyze the cough reflex under normal conditions; then we analyze the anatomy and the neuro-pathophysiology of the cough reflex arc. The aim of this review is to provide the anatomic and pathophysiologic elements of evaluation of the complex and multiple etiologies of cough.

Glycogen synthase kinase-3β modulation of glucocorticoid responsiveness in COPD

In chronic obstructive pulmonary disease (COPD), oxidative stress regulates the inflammatory response of bronchial epithelium and monocytes/macrophages through kinase modulation and has been linked to glucocorticoid unresponsiveness. Glycogen synthase-3β (GSK3β) inactivation plays a key role in mediating signaling processes upon reactive oxygen species (ROS) exposure. We hypothesized that GSK3β is involved in oxidative stress-induced glucocorticoid insensitivity in COPD. We studied levels of phospho-GSK3β-Ser9, a marker of GSK3β inactivation, in lung sections and cultured monocytes and bronchial epithelial cells of COPD patients, control smokers, and nonsmokers. We observed increased levels of phospho-GSK3β-Ser9 in monocytes, alveolar macrophages, and bronchial epithelial cells from COPD patients and control smokers compared with nonsmokers. Pharmacological inactivation of GSK3β did not affect CXCL8 or granulocyte-macrophage colony-stimulating factor (GM-CSF) expression but resulted in glucocorticoid insensitivity in vitro in both inflammatory and structural cells. Further mechanistic studies in monocyte and bronchial epithelial cell lines showed that GSK3β inactivation is a common effector of oxidative stress-induced activation of the MEK/ERK-1/2 and phosphatidylinositol 3-kinase/Akt signaling pathways leading to glucocorticoid unresponsiveness. In primary monocytes, the mechanism involved modulation of histone deacetylase 2 (HDAC2) activity in response to GSK3β inactivation. In conclusion, we demonstrate for the first time that ROS-induced glucocorticoid unresponsiveness in COPD is mediated through GSK3β, acting as a ROS-sensitive hub.

Bronchial inflammation and bacterial load in stable COPD is associated with TLR4 overexpression

Toll-like receptors (TLRs) and nucleotide-binding oligomerisation domain (NOD)-like receptors (NLRs) are two major forms of innate immune sensors but their role in the immunopathology of stable chronic obstructive pulmonary disease (COPD) is incompletely studied. Our objective here was to investigate TLR and NLR signalling pathways in the bronchial mucosa in stable COPD. Using immunohistochemistry, the expression levels of TLR2, TLR4, TLR9, NOD1, NOD2, CD14, myeloid differentiation primary response gene 88 (MyD88), Toll-interleukin-1 receptor domain-containing adaptor protein (TIRAP), and the interleukin-1 receptor-associated kinases phospho-IRAK1 and IRAK4 were measured in the bronchial mucosa of subjects with stable COPD of different severity (n=34), control smokers (n=12) and nonsmokers (n=12). The bronchial bacterial load of Pseudomonas aeruginosa, Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae was measured by quantitative real-time PCR. TLR4 and NOD1 expression was increased in the bronchial mucosa of patients with severe/very severe stable COPD compared with control subjects. TLR4 bronchial epithelial expression correlated positively with CD4+ and CD8+ cells and airflow obstruction. NOD1 expression correlated with CD8+ cells. The bronchial load of P. aeruginosa was directly correlated, but H. influenzae inversely correlated, with the degree of airflow obstruction. Bacterial load did not correlate with inflammatory cells. Bronchial epithelial overexpression of TLR4 and NOD1 in severe/very severe stable COPD, associated with increased bronchial inflammation and P. aeruginosa bacterial load, may play a role in the pathogenesis of COPD. Inflammation, bacterial load and active antibacterial immune response involving TLR4 and NOD1 in stable COPD http://ow.ly/S1fp308qcwp

Tiotropium and salmeterol/fluticasone combination do not cause oxygen desaturation in COPD

It has been documented that tiotropium is less likely to induce oxygen desaturation in stable COPD patients compared to long-acting beta2-agonists (LABAs) and combined administration of a LABA and an inhaled corticosteroid (ICS) reduces the potential for acute effects of LABA on blood-gas tensions. In this study, we have compared the acute effects of tiotropium 18 microg and salmeterol/fluticasone combination (SFC) 50/250 microg on arterial blood gases in 20 patients with stable COPD. Each subject was studied on 2 days, separated from one another by at least 4 days. Blood specimens were taken just before the inhalation and at 15, 30, 60, 180 and 360 min after inhalation of each treatment, and spirometry was performed at the same time points. As expected, both treatments significantly improved FEV1 (greatest changes were 0.20 L, 95% CI: 0.13-0.27 at 360 min after tiotropium; and 0.13 L, 95% CI: 0.06-0.19 at 180 min after SFC). The greatest mean changes from baseline in PaO2 were -1.7 (95% CI: -4.0 to 0.6)mmHg, p=0.134, after tiotropium; -0.8 (95% CI: -2.2 to 0.6)mmHg, after SFC. Both changes were observed after 15 min. Both drugs caused a small decrease in PaCO2 (greater changes: -1.9 (95% CI -3.2 to -0.6)mmHg, p=0.005 at 60 min after tiotropium; and -2.4 (95% CI: -3.5 to -1.3) mmHg, p=0.0002 at 180 min after SFC). These results indicate that both tiotropium and SFC are able to induce a significant long-last bronchodilation without affecting arterial blood gases. Moreover, they confirm that the impact of tiotropium on PaO2 is small and without clinical significance and the addition of a LABA to an ICS can reduce the potentially dangerous acute effect of the LABA on blood gases.

Sexual intercourse and respiratory failure

Sexual activity is an important component of quality of life in patients suffering from chronic illnesses. To our knowledge, the effects of sexual activity on gas exchange in patients with respiratory failure have not been yet studied. To such an extent, we evaluated the oxygen saturation (SaO2), by a pulse oxymeter, during three different sexual performances in a 63-yr-old patient affected by chronic obstructive pulmonary disease (COPD) on long-term oxygen therapy (LTOT). The sexual performances were divided in four periods: basal, sex, 10 min after sex and relax. In each performance during sex, we observed a significant increase of either heart rate (HR) or SaO2, with the highest value of the latter achieved within the 10 min of the post-sex period. SaO2 returned to basal value (pre-sex) by the end of the relax period. We conclude that the observed improvement of SaO2 during sexual activity might be due to a better ventilation/perfusion ratio (V/Q) obtained for either an increase of ventilation (hyperventilation) and perfusion (tachycardia), without significant muscle expenditure.

Standards of suitability for the management of chronic obstructive respiratory diseases

BackgroundChronic Obstructive Pulmonary Disease (COPD) ranks third as cause of mortality and disability-adjusted life years (DALY) worldwide and also in Italy it imposes a huge health, social and economic load. Early symptoms of COPD are often disregarded by patients and physicians, spirometry is underutilized, and the diagnosis is delayed till the disease has reached a distinct severity level. Despite the availability of various guidelines, the behavior of health workers involved in the management of COPD is still rather unlike. These considerations are the reason why in October 2013 AIMAR (Interdisciplinary Scientific Association for Research in Lung Disease) devised and organized a “Third Consensus Conference”, aimed at pointing out the standards of suitability for COPD management. In this context three important topics of discussion were identified: early and more widespread diagnosis, management of acute and subacute phases, long-term assistance to chronic patients.MethodsThe procedure recommended by the Italian Health Superior Institute (ISS) for Consensus Conferences organization was applied. The Conference was structured in three sessions, each dealing with one of the above mentioned topics and including a short update of the subject-matter and presentation, discussion and voting of some statements with a choice ranging from total agreement to total disagreement or no knowledge. The results of voting were eventually recorded in the document, reviewed by an independent jury, that forms the substance of this paper.ResultsThe essential role of spirometry, the need for distinguish between different COPD phenotypes, and the obligatoriness to base on the blood gas analysis findings the long-term oxygen therapy, were largely agreed, as well as the need for interventions aimed at decreasing the rate of acute exacerbations. More specific topics like the use of noninvasive ventilation, recognizing the factors affecting outcome and mortality, the choice of pharmacological and non pharmacological treatments in COPD patients led to lively discussing, but they did not always reach the total agreement, probably because of insufficient familiarity with these problems and of diversities in organization and instruments availability. The chronic respiratory assistance was treated with particular regard to smoking cessation, whose implementation is still insufficient. Many doubts rose due to uncertainty, lack of ability and standardization of procedures, insufficient institutional support, and difficulties to realize a network for assistance to chronic patients.ConclusionsThe results of this Third Consensus Conference revealed some certainties and many doubts and diversities of view also on topics whose importance is well demonstrated in scientific literature. Thus, there is still a long distance to cover before reaching a suitable standardization of COPD management and such situation urges the need for improving not only the health professional’s operativeness but also the organizational support by competent institutions. In this context some initiatives organized by AIMAR in cooperation with other respiratory scientific societies and patients’ associations are going on.