What do polymorphisms tell us about the mechanisms of COPD?

Diagnostic Challenges and Pathogenetic Differences in Biomass-Smoke-Induced versus Tobacco-Smoke-Induced COPD: A Comparative Review

Background: Chronic Obstructive Pulmonary Disease (COPD) is a major global health challenge, primarily driven by exposures to tobacco smoke and biomass smoke. While Tobacco-Smoke-Induced COPD (TSCOPD) has been extensively studied, the diagnostic challenges and distinct pathogenesis of Biomass-Smoke-Induced COPD (BSCOPD), particularly in low- and middle-income countries, remain underexplored. Objective: To explore the differences in clinical manifestations, pulmonary function, and inflammatory profiles between BSCOPD and TSCOPD and highlight the diagnostic complexities of BSCOPD. Methods: This review analyzes the current literature comparing BSCOPD with TSCOPD, focusing on distinctive pathophysiological mechanisms, inflammatory markers, and oxidative stress processes. Results: BSCOPD presents differences in clinical presentation, with less emphysema, smaller airway damage, and higher rates of pulmonary hypertension compared to TSCOPD. BSCOPD is also characterized by bronchial hyperresponsiveness and significant hypoxemia, unlike TSCOPD, which exhibits severe airflow obstruction and emphysema. Additionally, the inflammatory profile of BSCOPD includes distinct mucous hypersecretion and airway remodeling. Conclusions: The unique genetic, epigenetic, and oxidative stress mechanisms involved in BSCOPD complicate its diagnosis and management. Biomass smoke's underrecognized impact on accelerated lung aging and exacerbation mechanisms emphasizes the need for targeted research to refine diagnostic criteria and management strategies for BSCOPD. Future directions: Further research should focus on identifying specific biomarkers and molecular pathways to enhance early diagnosis and improve clinical outcomes in populations exposed to biomass smoke.

Genetic polymorphisms in MIR1208 and MIR5708 are associated with susceptibility to COPD in the Chinese population

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by limited airflow and is influenced by genetic and environmental factors. The purpose of this study was to investigate the effects of gene polymorphisms in MIR5708 and MIR1208 on COPD risk.

METHODS

Four single nucleotide polymorphisms (SNPs) in MIR5708 (rs6473227 and rs16907751) and MIR1208 (rs2608029 and rs13280095) were selected and genotyped among 315 COPD patients and 314 healthy controls using the Agena MassARRAY platform. SPSS 18.0 was used for statistical analysis and data processing. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the association between genetic variants of MIR1208 and MIR5708 and COPD risk.

RESULTS

The results suggested that rs16907751 variants in MIR5708 contributed to an increased susceptibility to COPD in the allelic (P = 0.001), co-dominant (homozygous) (P = 0.001), dominant (P = 0.017), recessive (P = 0.002), and additive (P = 0.002) models. The effects of MIR5708 and MIR1208 gene polymorphisms on the risk of COPD were age-, sex-, smoking status-, and BMI-related. Furthermore, the C-A and G-A haplotypes of rs2608029 and rs13280095 in MIR1208 were identified as risk factors for COPD in the population over 70 years (P = 0.029) and in women (P = 0.049), respectively. Finally, significant associations between rs16907751genotypes with pulse rate and forced expiratory volume in 1 s were found among COPD patients.

CONCLUSION

Genetic polymorphisms in MIR5708 and MIR1208 are associated with increased risk of COPD in China.

Hedgehog pathway and its inhibitors in chronic obstructive pulmonary disease (COPD)

COPD affects millions of people and is now ranked as the third leading cause of death worldwide. This largely untreatable chronic airway disease results in irreversible destruction of lung architecture. The small lung hypothesis is now supported by epidemiological, physiological and clinical studies. Accordingly, the early and severe COPD phenotype carries the most dreadful prognosis and finds its roots during lung growth. Pathophysiological mechanisms remain poorly understood and implicate individual susceptibility (genetics), a large part of environmental factors (viral infections, tobacco consumption, air pollution) and the combined effects of those triggers on gene expression. Genetic susceptibility is most likely involved as the disease is severe and starts early in life. The latter observation led to the identification of Mendelian inheritance via disease-causing variants of SERPINA1 - known as the basis for alpha-1 anti-trypsin deficiency, and TERT. In the last two decades multiple genome wide association studies (GWAS) identified many single nucleotide polymorphisms (SNPs) associated with COPD. High significance SNPs are located in 4q31 near HHIP which encodes an evolutionarily highly conserved physiological inhibitor of the Hedgehog signaling pathway (HH). HHIP is critical to several in utero developmental lung processes. It is also implicated in homeostasis, injury response, epithelial-mesenchymal transition and tumor resistance to apoptosis. A few studies have reported decreased HHIP RNA and protein levels in human adult COPD lungs. HHIP^+/- murine models led to emphysema. HH pathway inhibitors, such as vismodegib and sonidegib, are already validated in oncology, whereas other drugs have evidenced in vitro effects. Targeting the Hedgehog pathway could lead to a new therapeutic avenue in COPD. In this review, we focused on the early and severe COPD phenotype and the small lung hypothesis by exploring genetic susceptibility traits that are potentially treatable, thus summarizing promising therapeutics for the future.

Complex Evaluation of Surfactant Protein A and D as Biomarkers for the Severity of COPD

Purpose

Pulmonary surfactant proteins A (SP-A) and D (SP-D) are lectins, involved in host defense and regulation of pulmonary inflammatory response. However, studies on the assessment of COPD progress are limited.

Patients and Methods

Pulmonary surfactant proteins were obtained from the COPD mouse model induced by cigarette and lipopolysaccharide, and the specimens of peripheral blood and bronchoalveolar lavage (BALF) in COPD populations. H&E staining and RT-PCR were performed to demonstrate the successfully established of the mouse model. The expression of SP-A and SP-D in mice was detected by Western Blot and immunohistochemistry, while the proteins in human samples were measured by ELISA. Pulmonary function test, inflammatory factors (CRP, WBC, NLR, PCT, EOS, PLT), dyspnea index score (mMRC and CAT), length of hospital stay, incidence of complications and ventilator use were collected to assess airway remodeling and progression of COPD.

Results

COPD model mice with emphysema and airway wall thickening were more prone to have decreased SP-A, SP-D and increased TNF-α, TGF-β, and NF-kb in lung tissue. In humans, SP-A and SP-D decreased in BALF, but increased in serum. The serum SP-A and SP-D were negatively correlated with FVC, FEV1, FEV1/FVC, and positively correlated with CRP, WBC, NLR, mMRC and CAT scores (P < 0.05, respectively). The lower the SP-A and SP-D in BALF, the worse the lung function and the increased probability of complications and ventilator use. Moreover, the same trend emerged in COPD patients grouped according to GOLD severity grade (Gold 1–2 group vs Gold 3–4 group). The worse the patient’s condition, the more pronounced the change.

Conclusion

This study suggests that SP-A and SP-D may be related to the progression and prognostic evaluation of COPD in terms of airway remodeling, inflammatory response and clinical symptoms, and emphasizes the necessity of future studies of surfactant protein markers in COPD.

Psycho-cognitive assessment and quality of life in older adults with chronic obstructive pulmonary disease-carrying the rs4713916 gene polymorphism (G/A) of gene FKBP5 and response to pulmonary rehabilitation: a proof of concept study

PURPOSE

Chronic obstructive pulmonary disease (COPD) is characterized by pulmonary and extra-pulmonary multi-morbidity including depression, anxiety and cognitive disorders. Several studies investigated the association of the FKBP5 gene polymorphisms with susceptibility to anxiety, depression, and behavioral disorders. The FKBP5 gene codifies the FKBP51 protein which modulates the glucocorticoid receptor in the adaptive stress response. Genetic variants of the FKBP5 gene have been associated to a higher risk of developing mental disorders. We analyzed the association of genetic variants and stress exposure investigating the susceptibility to psychological distress and the impact on cognitive balance and quality of life (QoL) of COPD patients carrying the rs4713916 polymorphism (G/A) and we examined its association, with COPD rehabilitative outcomes.

MATERIALS AND METHODS

A pilot study evaluated cognitive, psychological, clinical alterations/disorders, QoL, and coping strategies in 70 older adults with COPD, undergoing pulmonary rehabilitation, stratified according to the FKBP5 rs4713916 genotype (GG or GA).

RESULTS

Carriers of rs4713916 polymorphisms (G/A) show better cognitive performances, a higher degree of independence in the daily living activities, better QoL, no presence of depressive mood and anxiety symptoms, no family history of psychiatric disorders, more ability to cope with stressors by avoiding emotions but demanding emotional support, and lesser use of anti-anxiety, anti-depressant, anti-psychotic, hypnotic-sedative drugs. No difference was found in the number of comorbidities.

CONCLUSION

These results offer valuable insights into the role of FKBP5 in the complex network of mechanisms associated to clinical, psychological and behavioral features of COPD patients.

Total Antioxidant Status in Stable Chronic Obstructive Pulmonary Disease

Objective

This study evaluates the total antioxidant status (TAS) in plasma of stable chronic obstructive pulmonary disease (COPD) patients. Earlier studies of their relationship showed inconsistent findings.

Patients and Methods

We compared TAS between 90 COPD patients and 30 age- and sex-matched controls (mean age 67 ± 7.9, 87 males and 33 females) according to airway obstruction severity, gender, smoking status (current/ former/ non-smoker), smoking-dose, the number of exacerbations in the previous year, nutritional status and hypercapnia.

Results

There were no differences in pack-years between COPD and controls, neither in COPD groups. The median time from the last exacerbation was 5 months (interquartile range 3-8.3). TAS was significant higher in COPD than controls (1.68 [1.55-1.80] versus 1.59 [1.54-1.68], respectively; P = 0.03). TAS was significantly higher in COPD men than women (1.7 [1.6-1.8] versus 1.57 [1.5-1.7], respectively; P = 0.001). In COPD groups, there were no significant differences between the severity of airway obstruction and TAS. We found significant positive correlation between pack-years and TAS in all participants (Rho = 0.429, P = 0.004) and COPD patients (Rho = 0.359, P = 0.02), but not in controls. TAS was a significant predictor of COPD (β = 3.26; P = 0.04; OR = 26.01; 95% CI: 1.20 to 570.8). We failed to find significant differences between TAS and smoking status, frequency of exacerbations in the previous year, nutritional status and hypercapnia.

Conclusion

TAS was a significant predictor of COPD. TAS was a significantly higher in stable COPD than controls, higher in COPD men than women, but there was no significant correlation between TAS and the airway obstruction severity. Our results suggest that it could be appropriate to include the time from the last exacerbation in the oxidant-antioxidant balance analysis of COPD patients.

Amerindian Ancestry Influences Genetic Susceptibility to Chronic Obstructive Pulmonary Disease

The contribution of genetic ancestry on chronic obstructive pulmonary disease (COPD) predisposition remains unclear. To explore this relationship, we analyzed the associations between 754,159 single nucleotide polymorphisms (SNPs) and risk of COPD (n = 214 cases, 193 healthy controls) in Talca, Chile, considering the genetic ancestry and established risk factors. The proportion of Mapuche ancestry (PMA) was based on a panel of 45 Mapuche reference individuals. Five PRDM15 SNPs and two PPP1R12B SNPs were associate with COPD risk (p = 0.05 to 5×10^-4) in those individuals with lower PMA. Based on linkage disequilibrium and sliding window analyses, an adjacent PRDM15 SNPs were associated with COPD risk in the lower PMA group (p = 10^-3 to 3.77×10^-8). Our study is the first to report an association between PPP1R12B and COPD risk, as well as effect modification between ethnicity and PRDM15 SNPs in determining COPD risk. Our results are biologically plausible given that PPP1R12B and PRDM15 are involved in immune dysfunction and autoimmunity, providing mechanistic evidence for COPD pathogenesis and highlighting the importance to conduct more genome wide association studies (GWAS) in admixed populations with Amerindian descent.

Effects of genetic variations in Acads gene on the risk of chronic obstructive pulmonary disease

Short-chain acyl-CoA dehydrogenase (SCAD), encoded by the Acads gene, functions in the mitochondrial β-oxidation of saturated short-chain fatty acids. SCAD deficiency results in mitochondrial dysfunction, which is one underlying biological mechanism of chronic obstructive pulmonary disease (COPD) pathogenesis. In this case-control study, we aimed to examine the effects of Acads gene polymorphisms on the susceptibility to COPD. A total of 16 tagging single-nucleotide polymorphisms (SNPs) in Acads gene region was identified and genotyped in 646 unrelated ethnic Chinese Han individuals including 279 patients with COPD and 367 healthy controls, their allelic and genotypic associations with COPD were determined by different genetic models. Furthermore, we estimated the linkage disequilibrium and haplotypes from these tested variants and determined the effects of haplotypes on the risk of COPD. The allelic and genotypic frequencies of SNPs rs2239686 and rs487915 in Acads gene were significantly different between COPD patients and controls, no statistically significant results were observed for other SNPs. Minor alleles A of rs2239686 and T of rs487915 were associated with a decreased pulmonary function and an increased COPD risk in a dominant manner. Functional analysis indicated that the risk allele A of rs2239686 could increase Acads expressions and the intracellular reactive oxygen species content. Haplotype analysis revealed that the haplotypes CTCCT in block 2 (rs3794216-rs3794215-rs34491494-rs558314-rs7312316) as well as GC in block 3 (rs2239686-rs487915) were protective against COPD, while haplotypes CTCGC in block 2 and AT in block 3 exhibited significant associations with the increased susceptibility to COPD. Our results suggest that Acads gene could potentially be a risk factor of COPD and thus its genetic variants might be as genetic biomarkers to predict the COPD susceptibility.

Effects of Chronic Nicotine Inhalation on Systemic and Pulmonary Blood Pressure and Right Ventricular Remodeling in Mice

Cigarette smoking is the single most important risk factor for the development of cardiovascular and pulmonary diseases; however, the role of nicotine in the pathogenesis of these diseases is incompletely understood. The purpose of this study was to examine the effects of chronic nicotine inhalation on the development of cardiovascular and pulmonary disease with a focus on blood pressure and cardiac remodeling. Male C57BL6/J mice were exposed to air (control) or nicotine vapor (daily, 12 hour on/12 hour off) for 8 weeks. Systemic blood pressure was recorded weekly by radio-telemetry, and cardiac remodeling was monitored by echocardiography. At the end of the 8 weeks, mice were subjected to right heart catheterization to measure right ventricular systolic pressure. Nicotine-exposed mice exhibited elevated systemic blood pressure from weeks 1 to 3, which then returned to baseline from weeks 4 to 8, indicating development of tolerance to nicotine. At 8 weeks, significantly increased right ventricular systolic pressure was detected in nicotine-exposed mice compared with the air controls. Echocardiography showed that 8-week nicotine inhalation resulted in right ventricular (RV) hypertrophy with increased RV free wall thickness and a trend of increase in RV internal diameter. In contrast, there were no significant structural or functional changes in the left ventricle following nicotine exposure. Mechanistically, we observed increased expression of angiotensin-converting enzyme and enhanced activation of mitogen-activated protein kinase pathways in the RV but not in the left ventricle. We conclude that chronic nicotine inhalation alters both systemic and pulmonary blood pressure with the latter accompanied by RV remodeling, possibly leading to progressive and persistent pulmonary hypertension.

Airway epithelial cell differentiation relies on deficient Hedgehog signalling in COPD

BACKGROUND

Hedgehog (HH) pathway is constantly under scrutiny in the context of organ development. Lung morphogenesis requires HH signalling which participates thereafter to the pulmonary homeostasis by regulating epithelial cell quiescence and repair. Since epithelial remodelling is a hallmark of Chronic Obstructive Pulmonary Disease (COPD), we investigated whether the main molecular actors of HH pathway participate to airway epithelial cell differentiation and we analysed their alterations in COPD patients.

METHODS

Sonic HH (Shh) secretion was assessed by ELISA in airway epithelial cell (AEC) air-liquid interface culture supernatants. HH pathway activation was evaluated by RT-qPCR, western blot and immunostaining. Inhibition of HH signalling was achieved upon Shh chelation during epithelial cell differentiation. HH pathway core components localization was investigated in lung tissues from non-COPD and COPD patients.

FINDINGS

We demonstrate that progenitors of AEC produced Shh responsible for the activation of HH signalling during the process of differentiation. Preventing the ligand-induced HH activation led to the establishment of a remodelled epithelium with increased number of basal cells and reduced ciliogenesis. Gli2 activating transcription factor was demonstrated as a key-element in the regulation of AEC differentiation. More importantly, Gli2 and Smo were lost in AEC from COPD patients.

INTERPRETATION

Our data suggest that HH pathway is crucial for airway epithelial cell differentiation and highlight its role in COPD-associated epithelial remodelling.

To Evaluate the Effect of Chronic Obstructive Pulmonary Disease on Retinal and Choroidal Thicknesses Measured by Optical Coherence Tomography

Purpose

To evaluate the retinal and choroidal thicknesses in patients with chronic obstructive pulmonary disease using optical coherence tomography.

Methods

The study included 26 patients with chronic obstructive pulmonary disease (COPD) and 26 age-matched healthy control groups. Detailed ocular examinations were performed on all participants. Cirrus EDI-OCT (enhanced depth imaging-optical coherence tomography) was used for choroidal thickness measurements with frame enhancement software. The subfoveal area was used for choroidal thickness measurements.

Results

The patients with the chronic obstructive pulmonary disease had an average 239.13 ± 57.77 μm subfoveal choroidal thickness, and the control group had an average 285.02 ± 25 μm subfoveal choroidal thickness. The subfoveal choroidal thickness measurements revealed a statistically significant difference between patients and the control group (p < 0.05). There were no statistically significant differences between patients and control group regarding mean macular thickness, central macular thickness, and GCIPL (ganglion cell-inner plexiform layer) thickness. Also, there was no statistically significant difference between patients and control group regarding mean, superior, nasal, inferior, and temporal RNFL (retinal nerve fiber layer) thicknesses.

Conclusion

Chronic hypoxemia seems to cause decreased choroidal thickness in patients with chronic obstructive pulmonary disease.

FKBP5 rs4713916: A Potential Genetic Predictor of Interindividual Different Response to Inhaled Corticosteroids in Patients with Chronic Obstructive Pulmonary Disease in a Real-Life Setting

Background: Chronic obstructive pulmonary disease (COPD) is a common, preventable, and manageable lung disease characterized by large heterogeneity in disease presentation and grades impairment. Inhaled corticosteroids (ICS) are commonly used to manage COPD/COPD-exacerbation. The patient's response is characterized by interindividual variability without disease progression/survival modification. Objectives: We hypothesize that a therapeutic intervention may be more effective if single nucleotide polymorphisms (SNPs) are investigated. Methods: In 71 COPD patients under pulmonary rehabilitation, a small number of powerful SNPs, selected according to current literature, were analyzed; namely the glucocorticoid receptor gene NR3C1 (rs6190/rs6189/rs41423247), the glucocorticoid-induced transcript 1 gene (GLCCI1 rs37972), and the related co-chaperone FKBP5 gene (rs4713916). MDR1 rs2032582 was also evaluated. Lung function outcomes were assessed. Results: A significant association with functional outcomes, namely FEV₁ (forced expiration volume/one second) and 6MWD (six-minutes walking distance), was found for rs4713916 and weakly for rs37972. The genotype rs4713916(GA) and, in a lesser extent, the genotype rs37972(TT), were more favorable than the wild-type. Conclusions: Our study supports a possible picture of pharmacogenomic control for COPD intervention. rs4713916 and, possibly, rs37972 may be useful predictors of clinical outcome. These results may help to tailor an optimal dose for individual COPD patients based on their genetic makeup.

Biomarkers of DNA damage in COPD patients undergoing pulmonary rehabilitation: Integrating clinical parameters with genomic profiling

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by severe respiratory symptoms. COPD shows several hallmarks of aging, and an increased oxidative stress, which is responsible for different clinical and molecular COPD features, including an increased frequency of DNA damage. The current pharmacological treatment options for COPD are mostly symptomatic, and generally do not influence disease progression and survival. In this framework, pulmonary rehabilitation is the most effective therapeutic strategy to improve physical performance, reducing hospital readmissions and mortality. Response to rehabilitation may greatly differ among patients calling for a personalized treatment. In this paper we will investigate in a group of COPD patients those variables that may predict the response to a program of pulmonary rehabilitation, integrating clinical parameters with cellular and molecular measurements, offering the potential for more effective and individualized treatment options. A group of 89 consecutive COPD patients admitted to a 3-weeks Pulmonary Rehabilitation (PR) program were evaluated for clinical and biological parameters at baseline and after completion of PR. DNA fragmentation in cryopreserved lymphocytes was compared by visual scoring and using the Comet Assay IV analysis system. The comparison of DNA damage before and after PR showed a highly significant increase from 19.6 ± 7.3 at admission to 21.8 ± 7.2 after three weeks of treatment, with a significant increase of 2.46 points (p < 0.001). Higher levels of DNA damage were observed in the group of non- responders and in those patients receiving oxygen therapy. The overall variation of %TI during treatment significantly correlated with the level of pCO₂ at admission and negatively with the level of IL-6 at admission. Measuring the frequency of DNA damage in COPD patients undergoing pulmonary rehabilitation may provide a meaningful biological marker of response and should be considered as additional diagnostic and prognostic criterion for personalized rehabilitation programs.