Air pollution has become a growing invisible killer in recent years and is major cause of morbidity and mortality globally. India stands 10th among the highly polluted countries with an average PM10 level of 134μg/m3 per year. It is also reported that 99% of India's population comes across air pollution level that exceed the World Health Organization Air Quality Guideline (AQG), PM2.5 permissible levels of 10 μg/m3. Maternal exposure to air pollution has a serious health outcome to the offspring because it can affect embryonic phases of development during the gestation period. Fetus is more prone to air pollution effect during embryonic developmental phases due to oxidative stress as antioxidant mechanisms are lacking at that stage. Any injury during this vulnerable period (embryonic phase) will have long-term impact on offspring health both in early and later in life. Epidemiological studies have revealed that maternal exposure to air pollution increases the risk of developing airways disease in offspring due to impaired lung development in utero. In this review, we discuss cellular mechanisms involved in maternal exposure to air pollution and how it can impact development of airways disease in offspring. Better understanding of these mechanisms in context of maternal exposure to air pollution can offer newer avenue to prevent development of airways disease in offspring.

Anatomical airways parameters as length, diameter and angles have a strong effect on the flow dynamics. Aiming to explore the effect of variations of the bifurcation angle (BA) and carina rounding radius (CRR) of lower human airways on the respiratory processes, numerical simulations of airflow during inhalation and exhalation were performed using a synthetic bifurcation models. Geometries for the airways models were parameterized based on a set of different BA's and several CRR's. A range of Reynolds numbers (\Reyn) relevant to the human breathing process were selected to analyzed the airflow behaviour. The numerical results show a significant influence of BA and the CRR on the development of the airflow within the airways, and therefore affecting some relevant features of the flow, namely the deformation of velocity profiles, alterations of pressure drop, the flow patterns, and finally enhance or attenuation of wall shear stresses (WSS) appearing during the regular respiratory process. Numerical results show that increases in the bifurcation angle value are accompanied by pressure increases of about 20\%, especially in the regions close to the bifurcation. Similarly, increases in the BA value lead to a reduction in peak shear stresses of up to 70\%. For the ranges of angles and radii explored, an increase in pressure of about 20\% and a reduction in wall shear stress of more than 400\% were obtained by increasing the carina rounding radius. Analysis of the coherent structures and secondary flow patterns also revealed a direct relationship between the location of the vortical structures, the local maxima of the velocity profiles and the local vorticity minima. This relationship was observed for all branches analysed, for both the inhalation and exhalation processes of the respiratory cycle.

This manuscript is aimed at encouraging those interested in biofilms and their effects on microbial communities to view the study of chronic airways disease as one of the most challenging and potentially rewarding areas to focus on. To do this it is necessary to review how we have reached 2023 having made so little progress. It is more than two hundred years ago since the term bronchitis was proposed to describe diseases affecting the airways rather than the respiratory zone of the lungs. The main histological features were described in Laennec’s text of 1819. By the mid C20th it was recognised that the two great drivers of chronic respiratory symptoms were inhaled toxins and chronic bacterial infections. The widespread availability of antibiotics in subsequent years had a dramatic impact on mortality from pneumonia, greatly reduced the prevalence of chronic symptoms after acute lower respiratory tract infections, transformed the lives of many with bronchiectasis and appeared to play a major role in the dramatic fall in prevalence of bronchiectasis. Unfortunately, during the following 70 years the importance of dealing with a chronic bacterial bronchitis was largely forgotten. While two artificial diseases ‘COPD’ and ‘bronchiectasis’ have been the subject of numerous guidelines, chronic bacterial bronchitis has been out in the cold. Antibiotics have in theory been reserved for those with established damage in the form of bronchiolitis and impaired lung function as defined by an arbitrary FEV1/FVC ratio and even then there is a disconnect with a minimum of 2 weeks being prescribed for exacerbations of bronchiectasis and the use of long term inhaled and oral macrolides frequently being advocated while a 5 day course is reserved for an exacerbation in a patient with COPD. The loss of focus on the role of antibiotics has a number of causes – a desire to ration antibiotic as part of ‘antibiotic stewardship’, the potential cost of treatment, the failure to ‘cure’ patients with chronic bronchitis and the difficulty in dealing with a disease whose morbidity at any given time can range from a mild cough and production of phlegm in the morning with no obvious impact on daily function to troublesome cough, sputum production and significant ill health. This was compounded by the vagaries of culture based diagnosis and the observation that more than one potential pathogen was often present. As a result chronic bacterial bronchitis was relegated to the ‘too hard to deal with’ box and many of the lessons of the past were forgotten. Revisiting the field from the perspective of current understanding of bacterial behaviour in biofilms and how these alter the resident microbiota of the airways should ensure that a chronic bacterial bronchitis returns to centre stage in order to minimise respiratory morbidity and mortality. This review charts the history of our understanding and mis-understanding of the role of chronic bacterial bronchitis in airways disease and the pernicious effect of language in helping to ensure that this common and important condition became the elephant in the room. Focusing on the nature of chronic bacterial bronchitis is essential if we are to find ways of identifying it accurately and treat it effectively – new approaches will be extremely slow unless we recognise its importance and the challenges it poses.

COPD is a chronic inflammatory disease characterized by progressive airflow obstruction. Tobacco smoking is the main cause of COPD (COPD-TS), but chronic exposure to biomass smoke (COPD-BS), mainly wood smoke, is the second risk factor; both are considered to cause different phenotypes of COPD. COPD-BS is more eosinophilic than COPD-TS. The objective of the present study was to evaluate the serum level of interleukins involved in eosinophil maturation, recruitment, and survival, and their association with small airway obstruction, measuring cytokines by multiplex test (Bio-Plex) and evaluating the central airway resistance with impulse oscillometry (IOS), comparatively in patients with COPD due to biomass and smoking. The results showed that IL-1ra, IL-2, IL-4, IL-8, IL-9, IL-13, IL-17, and eotaxin were increased in COPD-BS related to COPD-TS. Resistance parameters showed that R5, X5, AX (area reactance), and R5-R20 were significantly higher in COPD-BS than in the COPD-TS group (p < 0.05). R20 was not different between the groups. These data suggest that the cytokines involved in the effect of eosinophils on airway inflammation in COPD-BS were increased compared with COPD-TS, which appears to be related to a predominance of peripheral airway obstruction in patients with COPD-BS more than in COPD-TS

Natural cycles underpin the very stuff of life. In this commentary we consider unnatural cycles: that is, anthropogenic activities which have a circularity, but whose nature is to have a detrimental effect on human health, exacerbating existing problems. Natural cycles have feedback loops, some of which have recently come to light, with an understanding that everything is connected in some way. In health, feedback loops are imperative in homeostatic mechanisms. However, in the unnatural cycle the feedback loops serve to reinforce (and in some cases amplify) negative problems. We offer a commentary on an unnatural cycle moving from air quality to lung function and back to air quality; we call this the lung disease unnatural cycle. We suggest where links occur, and where wider consideration of interactions between various disciplines can lead to breaking this unnatural (or vicious) cycle, changing it to a healthy cycle where individual health can be improved, along with better global scale outcomes. We suggest that many activities within this unnatural cycle occur within silos. However, the improved cycle incorporates joint activities at geological, health, and financial levels, to the mutual benefit of all, breaking the unnatural cycle, and improving health, life and financial costs.

Obstructive sleep apnea (OSA) is a common sleep disorder, and continuous positive airways pressure (CPAP) is the most effective treatment. Poor adherence is one of the major challenges in CPAP therapy. The recent boom of wearable optical sensors measuring oxygen saturation makes the at-home multiple-night CPAP titrations possible, which may essentially improve the adherence of CPAP therapy by optimizing its pressure in a real-life setting economically. We tested whether the oxygen desaturations (OD) measured in the arm muscle (arm_OD) by gold-standard frequency-domain multi-distance near-infrared spectroscopy (FDMD-NIRS) changes with titrated CPAP pressures in OSA patients together with polysomnography. We found that the arm_OD (2.08 ± 1.23%, mean ± standard deviation) was significantly smaller (P-value &lt;0.0001) than the fingertip OD (finger_OD) (4.46 ± 2.37%) measured by polysomnography pulse oximeter. Linear mixed-effects models suggested that CPAP pressure was a significant predictor for finger_OD but not for arm_OD. Since FDMD-NIRS measures a mixture of arterial and venous OD, whereas fingertip pulse oximeter measures arterial OD, our results of no association between arm_OD and finger_OD indicate that the arm_OD mainly represented venous desaturation. Arm_OD measured by near-infrared optical sensors may be not a suitable indicator of the effectiveness of CPAP titration.