The Impact of Aging on the Lung Alveolar Environment, Predetermining Susceptibility to Respiratory Infections

Pathological and Inflammatory Consequences of Aging

Aging is a complex, progressive, and irreversible biological process that entails numerous structural and functional changes in the organism. These changes affect all bodily systems, reducing their ability to respond and adapt to the environment. Chronic inflammation is one of the key factors driving the development of age-related diseases, ultimately causing a substantial decline in the functional abilities of older individuals. This persistent inflammatory state (commonly known as "inflammaging") is characterized by elevated levels of pro-inflammatory cytokines, an increase in oxidative stress, and a perturbation of immune homeostasis. Several factors, including cellular senescence, contribute to this inflammatory milieu, thereby amplifying conditions such as cardiovascular disease, neurodegeneration, and metabolic disorders. Exploring the mechanisms of chronic inflammation in aging is essential for developing targeted interventions aimed at promoting healthy aging. This review explains the strong connection between aging and chronic inflammation, highlighting potential therapeutic approaches like pharmacological treatments, dietary strategies, and lifestyle changes.

Influenza and Aging: Clinical Manifestations, Complications, and Treatment Approaches in Older Adults

Influenza, a highly contagious respiratory viral illness, poses significant global health risks, particularly affecting older and those with chronic health conditions. Influenza viruses, primarily types A and B, are responsible for seasonal human infections and exhibit a propensity for antigenic drift and shift, contributing to seasonal epidemics and pandemics. The severity of influenza varies, but severe cases often lead to pneumonia, acute respiratory distress syndrome, and multiorgan failure. Older adults, especially those over 65 years of age, face increased risks of immune senescence, chronic comorbidities, and decreased vaccine efficacy. Globally, influenza affects millions of people annually, with significant morbidity and mortality among older. Epidemiological patterns vary with climate, and risk factors include age, immunocompromised status, and preexisting chronic conditions. In older adults, influenza frequently results in hospitalization and death, which is exacerbated by immunosenescence and biological organ changes associated with aging. Clinical manifestations range from mild symptoms to severe complications such as viral pneumonia and multiorgan failure. Diagnosis often relies on antigen or molecular tests, with radiological examination aiding in severe cases. Treatment primarily involves antiviral agents, such as oseltamivir and peramivir, with the greatest benefit observed when initiated early. Management of severe cases may require hospitalization and supportive care, including addressing complications, such as secondary bacterial infections and cardiovascular events. This article highlights the need for improved vaccination strategies and novel treatments, including monoclonal antibodies and adoptive T cell therapies, to better manage severe influenza infections in vulnerable populations such as older.

Microbiome-Mucosal Immunity Nexus: Driving Forces in Respiratory Disease Progression

The importance of the complex interplay between the microbiome and mucosal immunity, particularly within the respiratory tract, has gained significant attention due to its potential implications for the severity and progression of lung diseases. Therefore, this review summarizes the specific interactions through which the respiratory tract-specific microbiome influences mucosal immunity and ultimately impacts respiratory health. Furthermore, we discuss how the microbiome affects mucosal immunity, considering tissue-specific variations, and its capacity in respiratory diseases containing asthma, chronic obstructive pulmonary disease, and lung cancer. Additionally, we investigate the external factors which affect the relationship between respiratory microbiome and mucosal immune responses. By exploring these intricate interactions, this review provides valuable insights into the potential for microbiome-based interventions to modulate mucosal immunity and alleviate the severity of respiratory diseases.

Prevalence and Risk Factors of Chronic Obstructive Pulmonary Disease Among Users of Primary Health Care Facilities in Morocco

Background

Chronic obstructive pulmonary disease (COPD) is a major public health problem. In Morocco, few studies have focused on COPD in primary health care facilities, whose main mission is prevention. The aim of our work is thus to assess the prevalence of COPD and to study the factors associated with this silent disease among users of health care facilities in Morocco.

Methods

This is a cross-sectional observational study of participants aged 40 and over. Data were collected by questionnaire. Pulmonary function testing was conducted using a spirometer before and after administration of a bronchodilator. COPD was defined as fixed ratio of the post-bronchodilator forced expiratory volume in 1 second / forced vital capacity less than 0.7. Logistic regression models were applied to define factors associated with COPD.

Results

From 550 participants aged 40 and over, we selected only 477 patients with exploitable spirometry results for inclusion in the final analysis. The mean age of participants was 54.91±11.92 years, and the female/male ratio was 1.59. The prevalence of COPD was 6.7% (95% CI; 4.6 to 9.3%), and was higher in men than in women (11.4% vs 3.8%, p=0.002). The prevalence of COPD increased significantly with age, from 3.3% in those aged 40 to 49 to 16.9% in those aged 70 and over (p=0.001). Current smokers had a higher prevalence of COPD than former and never smokers. Age, smoking, asthma diagnosis and childhood hospitalization for lung disease were risk factors associated with the development of COPD. Only 6.25% of participants identified as having COPD had previously been diagnosed with COPD.

Conclusion

COPD remains largely under-diagnosed among primary care consultants in Morocco. Efforts for early detection and promotion of prevention of the main risk factors need to be intensified in order to reduce the burden of this silent pathology on a national scale.

Estimating the global prevalence of chronic obstructive pulmonary disease (COPD): a systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major public health problem. The present study aims to provide a global and regional estimate of the prevalence of COPD based on spirometry according to the two most widely used diagnostic criteria of COPD: fixed ratio (FR) and lower limit of normal (LLN).

METHODS

We conducted a systematic review of the literature according to PRISMA guidelines. MEDLINE, Web of Sciences, and Scopus databases were searched to identify studies on the spirometry-based prevalence of COPD in individuals aged 40 years and older. The meta-analysis was performed using MedCalc 19 software.

RESULTS

In total, 42 of the 3393 studies reviewed were eligible for inclusion. The overall prevalence of COPD in people aged 40 years and older was 12.64% (95% CI 10.75%-14.65%) and 7.38% (95% CI 5.47% - 9.55%) based on FR and LLN criteria, respectively. By gender, men had a higher prevalence of COPD compared to women (15.47%; 95% CI 12.22%-19.02% for men versus 8.79%; 95% CI 6.94%-10.82% for women). Using the LLN criteria, the prevalence of COPD in both sexes was almost identical (8.67%; 95% CI 8.44%- 8.90% for men and 8.00%; 95% CI 6.42% - 9.73% for women). We reported a high prevalence of COPD among smokers and the elderly by both definitions of airway obstruction. Regional prevalence estimates using the FR definition indicate that the highest COPD prevalence was recorded in the Americas and the lowest was recorded in the Eastern Mediterranean region. Using the LLN definition, the highest prevalence was recorded in the Southeast Asian region and the lowest prevalence was recorded in the American region. The most common COPD stage was stage II, with a prevalence of 50.46%. The results indicate a huge lack of prevalence data in the African and Eastern Mediterranean region. The results were given using a random-effect model due to the high heterogeneity between studies.

CONCLUSION

Results show that the prevalence of COPD differs according to the diagnostic criteria used. In addition, management and prevention strategies targeting risk factors for COPD are certainly needed to reduce the global burden of this chronic respiratory disease.

Protection against lung pathology during obesity-accelerated ageing in mice by the parasitic worm product ES-62

Mice develop pathology in the lungs as they age and this may be accelerated by a high calorie diet (HCD). ES-62 is a protein secreted by the parasitic worm Acanthocheilonema viteae that is immunomodulatory by virtue of covalently attached phosphorylcholine (PC) moieties. In this study, we show that weekly treatment of C57BL/6J mice with ES-62 protected against pathology in the lungs in male but not female mice fed a HCD from 10 weeks of age as shown by reductions in cellular infiltration and airway remodelling, particularly up to 160 days of age. ES-62 also reduced gene expression of the cytokines IL-4 and IL-17 and in addition the TLR/IL-1R adaptor MyD88, in the lungs of male mice although HCD-induced increases in these inflammatory markers were not detected until between 340 and 500 days of age. A combination of two drug-like ES-62 PC-based small molecule analogues (SMAs), produced broadly similar protective effects in the lungs of male mice with respect to both lung pathology and inflammatory markers, in addition to a decrease in HCD-induced IL-5 expression. Overall, our data show that ES-62 and its SMAs offer protection against HCD-accelerated pathological changes in the lungs during ageing. Given the targeting of Th2 cytokines and IL-17, we discuss this protection in the context of ES-62's previously described amelioration of airway hyper-responsiveness in mouse models of asthma.

Back to the Basics: Usefulness of Naturally Aged Mouse Models and Immunohistochemical and Quantitative Morphologic Methods in Studying Mechanisms of Lung Aging and Associated Diseases

Aging-related molecular and cellular alterations in the lung contribute to an increased susceptibility of the elderly to devastating diseases. Although the study of the aging process in the lung may benefit from the use of genetically modified mouse models and omics techniques, these approaches are still not available to most researchers and produce complex results. In this article, we review works that used naturally aged mouse models, together with immunohistochemistry (IHC) and quantitative morphologic (QM) methods in the study of the mechanisms of the aging process in the lung and its most commonly associated disorders: cancer, chronic obstructive pulmonary disease (COPD), and infectious diseases. The advantage of using naturally aged mice is that they present characteristics similar to those observed in human aging. The advantage of using IHC and QM methods lies in their simplicity, economic accessibility, and easy interpretation, in addition to the fact that they provide extremely important information. The study of the aging process in the lung and its associated diseases could allow the design of appropriate therapeutic strategies, which is extremely important considering that life expectancy and the number of elderly people continue to increase considerably worldwide.

Tuberculosis in an Aging World

Tuberculosis (TB) is one of the leading causes of death due to its being an infectious disease, caused by the airborne pathogen Mycobacterium tuberculosis (M.tb). Approximately one-fourth of the world’s population is infected with latent M.tb, and TB is considered a global threat killing over 4000 people every day. The risk of TB susceptibility and mortality is significantly increased in individuals aged 65 and older, confirming that the elderly represent one of the largest reservoirs for M.tb infection. The elderly population faces many challenges that increase their risk of developing respiratory diseases, including TB. The challenges the elderly face in this regard include the following: decreased lung function, immuno-senescence, inflammaging, adverse drug effects, low tolerance to anti-TB drugs, lack of suitable diagnoses/interventions, and age-associated comorbidities. In order to find new therapeutic strategies to maintain lung homeostasis and resistance to respiratory infections as we age, it is necessary to understand the molecular and cellular mechanisms behind natural lung aging. This review focuses primarily on why the elderly are more susceptible to TB disease and death, with a focus on pulmonary function and comorbidities.