Telomeres in lung disease

The telomerase activator TA-65 protects from cigarette smoke-induced small airway remodeling in mice through extra-telomeric effects

Small airway remodeling (SAR) is a key phenomenon of airflow obstruction in smokers, leading to chronic obstructive pulmonary disease (COPD). SAR results in an increased thickness of small airway walls, with a combination of peribronchiolar fibrosis with increased fibrous tissue and accumulation of mesenchymal and epithelial cells. SAR pathogenesis is still unclear but recent data suggest that alterations in telomerase activity could represent a possible underlying mechanism of SAR. Our study was dedicated to identify a potential protective role of TA-65, a pharmacological telomerase activator, in a cigarette smoke (CS) model of SAR in mice, and to further precise if extra-telomeric effects of telomerase, involving oxidative stress modulation, could explain it. C57BL/6J mice were daily exposed to air or CS during 4 weeks with or without a concomitant administration of TA-65 starting 7 days before CS exposure. Morphological analyses were performed, and mucus production, myofibroblast differentiation, collagen deposition, as well as transforming growth factor-β1 (TGF-β1) expression in the small airway walls were examined. In addition, the effects of TA-65 treatment on TGF-β expression, fibroblast-to-myofibroblast differentiation, reactive oxygen species (ROS) production and catalase expression and activity were evaluated in primary cultures of pulmonary fibroblasts and/or mouse embryonic fibroblasts in vitro. Exposure to CS during 4 weeks induced SAR in mice, characterized by small airway walls thickening and peribronchiolar fibrosis (increased deposition of collagen, expression of α-SMA in small airway walls), without mucus overproduction. Treatment of mice with TA-65 protected them from CS-induced SAR. This effect was associated with the prevention of CS-induced TGF-β expression in vivo, the blockade of TGF-β-induced myofibroblast differentiation, and the reduction of TGF-β-induced ROS production that correlates with an increase of catalase expression and activity. Our findings demonstrate that telomerase is a critical player of SAR, probably through extra-telomeric anti-oxidant effects, and therefore provide new insights in the understanding and treatment of COPD pathogenesis.

Telomere Shortening and Its Association with Cell Dysfunction in Lung Diseases

Telomeres are localized at the end of chromosomes to provide genome stability; however, the telomere length tends to be shortened with each cell division inducing a progressive telomere shortening (TS). In addition to age, other factors, such as exposure to pollutants, diet, stress, and disruptions in the shelterin protein complex or genes associated with telomerase induce TS. This phenomenon favors cellular senescence and genotoxic stress, which increases the risk of the development and progression of lung diseases such as idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, SARS-CoV-2 infection, and lung cancer. In an infectious environment, immune cells that exhibit TS are associated with severe lymphopenia and death, whereas in a noninfectious context, naïve T cells that exhibit TS are related to cancer progression and enhanced inflammatory processes. In this review, we discuss how TS modifies the function of the immune system cells, making them inefficient in maintaining homeostasis in the lung. Finally, we discuss the advances in drug and gene therapy for lung diseases where TS could be used as a target for future treatments.

Shortened telomere length in peripheral blood leukocytes of patients with lung cancer, chronic obstructive pulmonary disease in a high indoor air pollution region in China

Lung cancer and chronic obstructive pulmonary disease (COPD) are closely linked diseases. In Xuanwei, China, the extremely high incidence and mortality rates of lung cancer and COPD are associated with exposure to household smoky coal burning. Previous studies found that telomere length was related to lung disease. The objective of this study is to investigate the relationship of peripheral blood leukocyte telomere length to both lung cancer and COPD, as well as indoor coal smoke exposure in Xuanwei. We measured telomere length using quantitative polymerase chain reaction (qPCR) in peripheral blood leukocytes of 216 lung cancer patients, 296 COPD patients, and 426 healthy controls from Xuanwei. The telomere length ratios (mean ± SD) in patients with lung cancer (0.76 ± 0.35) and COPD (0.81 ± 0.35) were significantly shorter than in that of controls (0.95 ± 0.39). Individuals with the shortest tertile telomere length had 3.90- and 4.54-fold increased risks of lung cancer and COPD, respectively, compared with individuals with the longest tertile telomere length. No correlation was found between telomere length and pack-years of smoking. In healthy subjects, coal smoke exposure level affected telomere length. Lung function was positively and negatively associated with telomere length and environmental exposure, respectively, when combination the control and COPD groups. The result suggests that shortened telomere length in peripheral blood leukocytes was associated with lung cancer and COPD and might be affected by coal smoke exposure level in Xuanwei. Whether variation in telomere length caused by environmental exposure has a role in lung cancer and COPD development and exacerbation needs further research.

Association between Telomere-Related Polymorphisms and the Risk of IPF and COPD as a Precursor Lesion of Lung Cancer: Findings from the Fukuoka Tobacco-Related Lung Disease (FOLD) Registry

BACKGROUND

Lung cancer coexisting with idiopathic pulmonary fibrosis (IPF) or chronic obstructive pulmonary disease (COPD) can lead to poor prognosis.  Telomere-related polymorphisms may be implicated in the pathogenesis of these three lung diseases.  As to elucidate the mechanism of lung cancer via IPF or COPD may enable early detection and early treatment of the disease, we firstly examined the association between telomere-related polymorphisms and the risk of IPF and COPD in a case-control study.

MATERIALS AND METHODS

A total of 572 patients with IPF (n = 155) or COPD (n = 417), who were derived from our on-going cohort study, and controls (n = 379), who were derived from our previous case-control study, were included in this study.  Telomerase reverse transcriptase (TERT) rs2736100, telomere RNA component (TERC) rs1881984, and oligonucleotide/oligosaccharide-binding fold containing1 (OBFC1) rs11191865 were genotyped with real-time PCR using TaqMan fluorescent probes. Unconditional logistic regression was used to assess the adjusted odds ratios and 95% confidence intervals.

RESULTS

TERT rs2736100 was significantly associated with the risk of IPF; increases in the number of this risk allele increased the risk of IPF (Ptrend = 0.008).  Similarly, TERT rs2736100 was associated with the risk of COPD.  In regard to the combined action of the three loci, increasing numbers of "at-risk" genotypes increased the risk of IPF in a dose-dependent manner (P trend=0.003).

CONCLUSIONS

TERT rs2736100 was associated with the risks of both IPF and COPD in a Japanese population. A combination of the "at-risk" genotypes might be important to identify the population at risk for IPF more clearly.

Potential Role of Cellular Senescence in Asthma

Cellular senescence is a complicated process featured by irreversible cell cycle arrest and senescence-associated secreted phenotype (SASP), resulting in accumulation of senescent cells, and low-grade inflammation. Cellular senescence not only occurs during the natural aging of normal cells, but also can be accelerated by various pathological factors. Cumulative studies have shown the role of cellular senescence in the pathogenesis of chronic lung diseases including chronic obstructive pulmonary diseases (COPD) and idiopathic pulmonary fibrosis (IPF) by promoting airway inflammation and airway remodeling. Recently, great interest has been raised in the involvement of cellular senescence in asthma. Limited but valuable data has indicated accelerating cellular senescence in asthma. This review will compile current findings regarding the underlying relationship between cellular senescence and asthma, mainly through discussing the potential mechanisms of cellular senescence in asthma, the impact of senescent cells on the pathobiology of asthma, and the efficiency and feasibility of using anti-aging therapies in asthmatic patients.

TERT gene polymorphisms are associated with chronic obstructive pulmonary disease risk in the Chinese Li population

Background

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide and is characterized by a partially reversible airflow limitation. Currently, many studies put forward that COPD is associated with both genetic and environmental factors. It has been reported that germline mutations in telomerase are risk factors for COPD susceptibility. In this study, we validated the association between TERT polymorphisms and COPD risk with a case–control study in the Chinese Li population.

Methods

A total of 279 COPD patients and 290 control individuals were recruited. We identified five single nucleotide polymorphisms (SNPs) in TERT that were associated with COPD. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in logistic regression models after adjusting for age and gender to assess the association.

Results

In the genetic model analysis, we found the “C/T‐T/T” genotype of rs10069690 in TERT was associated with an increased COPD risk in the dominant model (p = 0.046); the rs2853677 in TERT was significantly associated with increased COPD risk based on the codominant model (“A/G” genotype, p = 0.033), dominant model (A/G‐G/G genotype, p = 0.0091), and log‐additive model (p = 0.023). The rs2853676 in TERT could increase the risk of COPD in the dominant model (“C/T‐T/T” genotype, p = 0.026) and in the Log‐additive model (p = 0.022).

Conclusion

Our data shed new light on the association between TERT SNPs and COPD susceptibility in the Chinese Li population.

Peripheral blood telomere alterations in ground glass opacity (GGO) lesions may suggest malignancy

A ground glass opacity (GGO) lung lesion may represent early stage adenocarcinoma, which has an excellent prognosis upon prompt surgical resection. However, GGO lesions have broad differential diagnoses, including both benign and malignant lesions. Our objective was to study telomere length and telomerase activity in patients with suspected lung cancer in which GGO was the predominant radiographic feature. Knowledge of telomere biology may help distinguish malignant from benign radiographic lesions and guide risk assessment of these lesions. Peripheral blood samples were taken from 22 patients with suspected adenocarcinoma with the GGO radiographic presentation. Multidisciplinary discussion confirmed the need for surgery in all cases. We used an age and gender‐matched group without known lung disease as a control. Telomere length and aggregates were assessed by quantitative fluorescence in situ hybridization (QFISH) and quantitative PCR. Cell senescence was evaluated by senescence‐associated heterochromatin foci. Subjects with GGO lesions had a higher percentage of lymphocytes with shorter telomeres (Q‐FISH, P = 0.003). Furthermore, relative telomere length was also reduced among the GGO cases (qPCR, P < 0.05). Increased senescence was observed in the GGO group compared to controls (P < 0.001), with significant correlation between the senescence‐associated heterochromatin foci and aggregate formation (r = −0.7 and r = −0.44 for cases and controls, respectively). In conclusion, patients with resectable early adenocarcinoma demonstrate abnormal telomere length and cell senescence in peripheral blood leukocytes compared to control subjects. Abnormal telomere biology in the peripheral blood may increase suspicion of early adenocarcinoma among patients with GGO lesions.

Does Telomere Length Indicate Biological, Physical, and Cognitive Health Among Older Adults? Evidence from the Health and Retirement Study

Telomere length (TL) has been suggested as a biomarker that can indicate individual variability in the rate of aging. Yet, it remains unclear whether TL is related to recognized indicators of health in an aging, older nationally representative sample. We examine whether TL is associated with 15 biological, physical, and cognitive markers of health among older adults ages 54+. TL was assayed from saliva using quantitative polymerase chain reaction (T/S ratio) in the 2008 Health and Retirement Study (n = 4,074). We estimated probability of high-risk levels across indictors of health by TL and age-singly and jointly. TL was associated with seven indicators of poor functioning: high-density lipoprotein and total cholesterol, cystatin C, pulse pressure, body mass index, lung function, and walking speed. However, after adjusting for age, associations were substantially attenuated; only associations with cholesterol and lung function remained significant. Additionally, findings show TL did not add to the predictive power of chronological age in predicting poor functioning. While TL may not be a useful clinical marker of functional aging in an older adult population, it may still play an important role in longitudinal studies in young and middle aged populations that attempt to understand aging.

Effect of therapies-mediated modulation of telomere and/or telomerase on cancer cells radiosensitivity

Cancer is one of the leading causes of death in the world. Many strategies of cancer treatment such as radiotherapy which plays a key role in cancer treatment are developed and used nowadays. However, the side effects post-cancer radiotherapy and cancer radioresistance are two major causes of the limitation of cancer radiotherapy effectiveness in the cancer patients. Moreover, reduction of the limitation of cancer radiotherapy effectiveness by reducing the side effects post-cancer radiotherapy and cancer radioresistance is the aim of several radiotherapy-oncologic teams. Otherwise, Telomere and telomerase are two cells components which play an important role in cancer initiation, cancer progression and cancer therapy resistance such as radiotherapy resistance. For resolving the problems of the limitation of cancer radiotherapy effectiveness especially the cancer radio-resistance problems, the radio-gene-therapy strategy which is the use of gene-therapy via modulation of gene expression combined with radiotherapy was developed and used as a new strategy to treat the patients with cancer. In this review, we summarized the information concerning the implication of telomere and telomerase modulation in cancer radiosensitivity.

Short Telomere Length as a Biomarker Risk of Lung Cancer Development Induced by High Radon Levels: A Pilot Study

Long-term exposure to radon has been determined to be the second leading cause of lung cancer after tobacco smoking. However, an in-depth study of this topic has not been explicitly carried out in Chiang Mai (Thailand). This paper presents the results of an indoor radon level measurement campaign in dwellings of Chiang Mai using total of 110 detectors (CR-39) during one year. The results show that the average radon levels varied from 35 to 219 Bq/m³, with an overall average of 57 Bq/m³. The finding also shows that the average value is higher than the global average value of 39 Bq/m³. In addition, to examine the cause of lung cancer development among people with risk of chronic exposure to radon during their lifetime, 35 non-smoker lung cancer patients and 33 healthy nonsmokers were analyzed for telomere length. As expected, telomere length was significantly shorter in lung cancer patients than in healthy nonsmokers. Among healthy nonsmokers, the telomere length was significantly shorter in a high radon group than in an unaffected low radon group. To the best of our knowledge, our research provides the first attempt in describing the shortened telomeres in areas with high levels of environmental radon that might be related to lung cancer development.

The Telomere/Telomerase System in Chronic Inflammatory Diseases. Cause or Effect?

Telomeres are specialized nucleoprotein structures located at the end of linear chromosomes and telomerase is the enzyme responsible for telomere elongation. Telomerase activity is a key component of many cancer cells responsible for rapid cell division but it has also been found by many laboratories around the world that telomere/telomerase biology is dysfunctional in many other chronic conditions as well. These conditions are characterized by chronic inflammation, a situation mostly overlooked by physicians regarding patient treatment. Among others, these conditions include diabetes, renal failure, chronic obstructive pulmonary disease, etc. Since researchers have in many cases identified the association between telomerase and inflammation but there are still many missing links regarding this correlation, the latest findings about this phenomenon will be discussed by reviewing the literature. Our focus will be describing telomere/telomerase status in chronic diseases under the prism of inflammation, reporting molecular findings where available and proposing possible future approaches.

Accelerated telomere attrition in children and teenagers with α1-antitrypsin deficiency

Numerous studies have shown that oxidative stress accelerates telomere shortening in several lung pathologies. Since oxidative stress is involved in the pathophysiology of α1-antitrypsin deficiency (AATD), we hypothesised that telomere shortening would be accelerated in AATD patients. This study aimed to assess telomere length in AATD patients and to study its association with α1-antitrypsin phenotypes.

Telomere length, telomerase activity, telomerase reverse transcriptase (hTERT) expression and biomarkers of oxidative stress were measured in 62 children and teenagers (aged 2–18 years) diagnosed with AATD and 18 controls (aged 3–16 years).

Our results show that intermediate-risk (MZ; SZ) and high-risk (ZZ) AATD patients have significantly shorter telomeres and increased oxidative stress than controls. Correlation studies indicate that telomere length was related to oxidative stress markers in AATD patients. Multiple hypothesis testing revealed an association between telomere length, telomerase activity, hTERT expression and AATD phenotypes; high-risk patients showed shorter telomeres, lower hTERT expression and decreased telomerase activity than intermediate-risk and low-risk patients.

AATD patients show evidence of increased oxidative stress leading to telomere attrition. An association between telomere and α1-antitrypsin phenotypes is observed suggesting that telomere length could be a promising biomarker for AATD disease progression.

From "traction bronchiectasis" to honeycombing in idiopathic pulmonary fibrosis: A spectrum of bronchiolar remodeling also in radiology?

BACKGROUND

The diagnostic and prognostic impact of traction bronchiectasis on high resolution CT scan (HRCT) in patients suspected to have idiopathic pulmonary fibrosis (IPF) is increasing significantly.

MAIN BODY

Recent data demonstrated that cysts in honeycombing areas are covered by epithelium expressing bronchiolar markers. In IPF bronchiolization is the final consequence of a variety of pathogenic events starting from alveolar stem cell exhaustion, and ending in a abnormal/dysplastic proliferation of bronchiolar epithelium. CT scan features of traction bronchiectasis and honeycombing should be interpreted under the light of these new pathogenetic and morphologic considerations.

SHORT CONCLUSION

We suggest that in IPF subjects traction bronchiectasis and honeycombing -now defined as distinct entities on HRCT scan- are actually diverse aspects of a continuous spectrum of lung remodeling.

Telomere length in interstitial lung diseases

BACKGROUND

Interstitial lung disease (ILD) is a heterogeneous group of rare diseases that primarily affect the pulmonary interstitium. Studies have implicated a role for telomere length (TL) maintenance in ILD, particularly in idiopathic interstitial pneumonia (IIP). Here, we measure TL in a wide spectrum of sporadic and familial cohorts of ILD and compare TL between patient cohorts and control subjects.

METHODS

A multiplex quantitative polymerase chain reaction method was used to measure TL in 173 healthy subjects and 359 patients with various ILDs, including familial interstitial pneumonia (FIP). The FIP cohort was divided into patients carrying TERT mutations, patients carrying SFTPA2 or SFTPC mutations, and patients without a proven mutation (FIP-no mutation).

RESULTS

TL in all cases of ILD was significantly shorter compared with those of control subjects (P range: .038 to < .0001). Furthermore, TL in patients with idiopathic pulmonary fibrosis (IPF) was significantly shorter than in patients with other IIPs (P = .002) and in patients with sarcoidosis (P < .0001). Within the FIP cohort, patients in the FIP-telomerase reverse transcriptase (TERT) group had the shortest telomeres (P < .0001), and those in the FIP-no mutation group had TL comparable to that of patients with IPF (P = .049). Remarkably, TL of patients with FIP-surfactant protein (SFTP) was significantly longer than in patients with IPF, but similar to that observed in patients with other sporadic IIPs.

CONCLUSIONS

The results show telomere shortening across all ILD diagnoses. The difference in TL between the FIP-TERT and FIP-SFTP groups indicates the distinction between acquired and innate telomere shortening. Short TL in the IPF and FIP-no mutation groups is indicative of an innate telomere-biology defect, while a stress-induced, acquired telomere shortening might be the underlying process for the other ILD diagnoses.

Biomarkers in Interstitial lung diseases

Interstitial lung diseases (ILD)s represent a heterogeneous group of rare respiratory disorders, mostly chronic and associated with high morbidity and mortality. They are complex diseases that remain, in children, largely underdiagnosed and difficult to manage. Therefore, identification of biomarkers, which could be used for ILD diagnosis, measurements of disease severity and progression, and responsiveness to treatments, is a major challenge for clinical practice and for translational research. The present review focuses on blood biomarkers and provides an overview on the current information on molecular parameters of interest for ILD patient management.

Telomere length and telomerase activity in non-small cell lung cancer prognosis: clinical usefulness of a specific telomere status

Background

Considering previous data and the need to incorporate new biomarkers for the prognosis of solid tumours into the clinic, our aim in this work consists of evaluating the potential clinical use of telomeres and telomerase in non-small cell lung cancer (NSCLC).

Methods

Telomere status was established by determination of telomere length using the Terminal Restriction Fragment length method, and telomerase activity by the Telomeric Repeat Amplification Protocol in 142 NSCLCs and their corresponding control samples, obtained from patients submitted to surgery. Group-oriented curves for disease-free survival were calculated according to the Kaplan-Meier method considering telomere length, T/N ratio (telomere length in tumour to control tissue) and telomerase activity.

Results

Overall, tumours had significantly shorter telomeres compared with telomeres in control tissues (P = 0.027). More than 80 % of NSCLCs displayed telomerase activity. Regarding prognosis studies, patients whose tumours showed a mean telomere length (MTL) <7.29 Kb or T/N ratio <0.97 showed a significantly poor clinical evolution (P = 0.034 and P = 0.040, respectively). As result of a Cox multivariate analysis including pathologic state and lymph node dissemination, the MTL and T/N ratio emerged as independent significant prognostic factors.

Conclusions

Telomerase activity was identified as a marker of poor prognosis. The novel finding of this study is the independent prognosis role of a specific telomere status in NSCLC patients. According to our results, telomere function may emerge as a useful molecular tool that allow to select groups of NSCLC patients with different clinical evolution, in order to establish personalized therapy protocols.

Bone mineral density in patients with idiopathic pulmonary fibrosis

BACKGROUND

Decreased bone mineral density (BMD) has been reported in patients with interstitial lung disease. However, BMD has not been evaluated in steroid-naïve patients with idiopathic pulmonary fibrosis (IPF). We aimed to measure vertebral BMD and investigate its relationship with clinical features in steroid-naïve patients with IPF.

METHODS

We recruited 55 consecutive male patients with steroid-naïve IPF; 55 male smokers without chronic obstructive pulmonary disease or interstitial lung disease, matched by age, body mass index, and pack-years of smoking (control smokers); and 27 healthy young adults. Thoracic vertebral BMD was measured by computed tomography (CT). We further investigated the relationship of BMD with clinical features and quantitative CT indices of lung density in patients with IPF.

RESULTS

The thoracic vertebral BMD of patients with IPF was significantly lower than that of control smokers (139.9 ± 28.5 mg/mL vs 160.9 ± 39.5 mg/mL, p < 0.01). Fifteen patients (27.2%) had BMD more than 2.5 SD below the mean BMD of young adults. In patients with IPF, emphysema volume (EV) and its ratio to total lung volume (EV%) had a significantly negative correlation with BMD (r = -0.28, p = 0.04 and r = -0.39, p < 0.01, respectively). In stepwise multiple regression analysis, EV% was an independent explanatory variable for thoracic vertebral BMD.

CONCLUSION

A substantial percentage of steroid-naïve IPF patients had decreased BMD, and a significant association was observed between the extent of emphysema and BMD in IPF.

Diseases of pulmonary surfactant homeostasis

Advances in physiology and biochemistry have provided fundamental insights into the role of pulmonary surfactant in the pathogenesis and treatment of preterm infants with respiratory distress syndrome. Identification of the surfactant proteins, lipid transporters, and transcriptional networks regulating their expression has provided the tools and insights needed to discern the molecular and cellular processes regulating the production and function of pulmonary surfactant prior to and after birth. Mutations in genes regulating surfactant homeostasis have been associated with severe lung disease in neonates and older infants. Biophysical and transgenic mouse models have provided insight into the mechanisms underlying surfactant protein and alveolar homeostasis. These studies have provided the framework for understanding the structure and function of pulmonary surfactant, which has informed understanding of the pathogenesis of diverse pulmonary disorders previously considered idiopathic. This review considers the pulmonary surfactant system and the genetic causes of acute and chronic lung disease caused by disruption of alveolar homeostasis.

Telomere maintenance and the etiology of adult glioma

A growing body of epidemiologic and tumor genomic research has identified an important role for telomere maintenance in glioma susceptibility, initiation, and prognosis. Telomere length has long been investigated in relation to cancer, but whether longer or shorter telomere length might be associated with glioma risk has remained elusive. Recent data address this question and are reviewed here. Common inherited variants near the telomerase-component genes TERC and TERT are associated both with longer telomere length and increased risk of glioma. Exome sequencing of glioma patients from families with multiple affected members has identified rare inherited mutations in POT1 (protection of telomeres protein 1) as high-penetrance glioma risk factors. These heritable POT1 mutations are also associated with increased telomere length in leukocytes. Tumor sequencing studies further indicate that acquired somatic mutations of TERT and ATRX are among the most frequent alterations found in adult gliomas. These mutations facilitate telomere lengthening, thus bypassing a critical mechanism of apoptosis. Although future research is needed, mounting evidence suggests that glioma is, at least in part, a disease of telomere dysregulation. Specifically, several inherited and acquired variants underlying gliomagenesis affect telomere pathways and are also associated with increased telomere length.

Interstitial lung disease: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Population-based, longitudinal studies spanning decades linking risk factors in childhood, adolescence and early adulthood to incident clinical interstitial lung disease (ILD) events in late adulthood have not been performed. In addition, no observational or randomized clinical trials have been conducted; therefore, there is presently no evidence to support the notion that reduction of risk factor levels in early life prevents ILD events in adult life. Primary prevention strategies are host-directed interventions designed to modify adverse risk factors (i.e., smoking) with the goal of preventing the development of ILD, whereas primordial prevention for ILD can be defined as the elimination of external risk factors (i.e., environmental pollutants). As no ILD primary prevention studies have been previously conducted, we propose that research studies that promote implementation of primary prevention strategies could, over time, make a subset of ILD preventable. Herein, we provide a number of initial steps required for the future implementation of prevention strategies; this statement discusses the rationale and available evidence that support potential opportunities for primordial and primary prevention, as well as fertile areas for future research of preventive intervention in ILD.

Changes in telomere length and telomerase activity in human bronchial epithelial cells induced by coal tar pitch extract

Coal tar pitch is a confirmed human carcinogen and is composed mainly of polycyclic aromatic hydrocarbons.

Smoking accelerates aging of the small airway epithelium

BACKGROUND

Aging involves multiple biologically complex processes characterized by a decline in cellular homeostasis over time leading to a loss and impairment of physiological integrity and function. Specific cellular hallmarks of aging include abnormal gene expression patterns, shortened telomeres and associated biological dysfunction. Like all organs, the lung demonstrates both physiological and structural changes with age that result in a progressive decrease in lung function in healthy individuals. Cigarette smoking accelerates lung function decline over time, suggesting smoking accelerates aging of the lung. Based on this data, we hypothesized that cigarette smoking accelerates the aging of the small airway epithelium, the cells that take the initial brunt of inhaled toxins from the cigarette smoke and one of the primary sites of pathology associated with cigarette smoking.

METHODS

Using the sensitive molecular parameters of aging-related gene expression and telomere length, the aging process of the small airway epithelium was assessed in age matched healthy nonsmokers and healthy smokers with no physical manifestation of lung disease or abnormalities in lung function.

RESULTS

Analysis of a 73 gene aging signature demonstrated that smoking significantly dysregulates 18 aging-related genes in the small airway epithelium. In an independent cohort of male subjects, smoking significantly reduced telomere length in the small airway epithelium of smokers by 14% compared to nonsmokers.

CONCLUSION

These data provide biologic evidence that smoking accelerates aging of the small airway epithelium.

Premature lung aging and cellular senescence in the pathogenesis of idiopathic pulmonary fibrosis and COPD/emphysema

Different anatomic and physiological changes occur in the lung of aging people that can affect pulmonary functions, and different pulmonary diseases, including deadly diseases such as chronic obstructive pulmonary disease (COPD)/emphysema and idiopathic pulmonary fibrosis (IPF), can be related to an acceleration of the aging process. The individual genetic background, as well as exposure to a variety of toxic substances (cigarette smoke in primis) can contribute significantly to accelerating pulmonary senescence. Premature aging can impair lung function by different ways: by interfering specifically with tissue repair mechanisms after damage, thus perturbing the correct crosstalk between mesenchymal and epithelial components; by inducing systemic and/or local alteration of the immune system, thus impairing the complex mechanisms of lung defense against infections; and by stimulating a local and/or systemic inflammatory condition (inflammaging). According to recently proposed pathogenic models in COPD and IPF, premature cellular senescence likely affects distinct progenitors cells (mesenchymal stem cells in COPD, alveolar epithelial precursors in IPF), leading to stem cell exhaustion. In this review, the large amount of data supporting this pathogenic view are discussed, with emphasis on the possible molecular and cellular mechanisms leading to the severe parenchymal remodeling that characterizes, in different ways, these deadly diseases.