Contributions of cardiovascular risk and smoking to chronic obstructive pulmonary disease (COPD)-related changes in brain structure and function

Correlation between frailty and reduction in cortical thickness in patients with chronic obstructive pulmonary disease

Physical inactivity and cognitive impairment in patients with chronic obstructive pulmonary disease (COPD) can lead to frailty and poor prognoses. However, little is known regarding the association between frailty and the human brain. We hypothesized that the brain structure could change according to frailty in patients with COPD and focused on cortical thickness. Cortical thickness measured by magnetic resonance imaging and frailty scores using the Kihon Checklist (KCL) were assessed in 40 patients with stable COPD and 20 healthy controls. Among the 34 regions assessed, multiple regions were thinner in patients with COPD than in healthy individuals (p < 0.05). We found significant negative correlations between the eight regions and the KCL scores only in patients with COPD. After adjusting for age and cognitive impairment, the association between the left and six right regions remained statistically significant. The correlation coefficient was the strongest in the bilateral superior frontal gyrus (left: ρ = - 0.5319, p = 0.0006) (right: ρ = - 0.5361, p = 0.0005). Interestingly, among the KCL scores, the daily activity domain showed the strongest correlation (sensitivity, 90%; specificity, 73%) with the bottom quartile of the reduction in the superior frontal gyrus. Frailty in patients with COPD is associated with a thickness reduction in the cortical regions, reflecting social vulnerability.

The Abnormal Alternations of Brain Imaging in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review

Background

Cognitive impairment (CI) is an important extrapulmonary complication in patients with chronic obstructive pulmonary disease (COPD). Multimodal Neuroimaging Examination can display changes in brain structure and functions in patients with COPD.

Objective

The purpose of this systematic review is to provide an overview of the variations in brain imaging in patients with COPD and their potential relationship with CI. Furthermore, we aim to provide new ideas and directions for future research.

Methods

Literature searches were performed using the electronic databases PubMed, Scopus, and ScienceDirect. All articles published between January 2000 and November 2021 that met the eligibility criteria were included.

Results

Twenty of the 23 studies focused on changes in brain structure and function. Alterations in the brain's macrostructure are manifested in the bilateral frontal lobe, hippocampus, right temporal lobe, motor cortex, and supplementary motor area. The white matter microstructural changes initially appear in the bilateral frontal subcortical region. Regarding brain function, patients with COPD exhibited reduced frontal cerebral perfusion and abnormal alterations in intrinsic brain activity in the bilateral posterior cingulate cortex, precuneus, right lingual gyrus, and left anterior central gyrus. Currently, there is limited research related to brain networks.

Conclusion

CI in patients with COPD may present as a type of dementia different from Alzheimer's disease, which tends to manifest as frontal cognitive decline early in the disease. Further studies are required to clarify the neurobiological pathways of CI in patients with COPD from the perspective of brain connectomics based on the whole-brain system in the future.

The change of attention network functions and physiological adaptation during high-altitude hypoxia and reoxygenation

Previous studies have not reached a definitive conclusion regarding the effect of high-altitude hypoxia and reoxygenation on attention. To clarify the influence of altitude and exposure time on attention and the relations between physiological activity and attention, we conducted a longitudinal study to track attention network functions in 26 college students. The scores on the attention network test and physiological data, including heart rate, percutaneous arterial oxygen saturation (SpO₂), blood pressure, and vital capacity in pulmonary function measurement, were collected at five time-points: two weeks before arriving at high altitude (baseline), within 3 days after arriving at high altitude (HA3), 21 days after arriving at high altitude (HA21), 7 days after returning to sea level (POST7) and 30 days after returning to sea level (POST30). The alerting scores at POST30 were significantly higher than those at baseline, HA3 and HA21; the orienting scores at HA3 were lower than those at POST7 and POST30; the executive control scores at POST7 were significantly lower than those at baseline, HA3, HA21, and POST30; and the executive control scores at HA3 were significantly higher than those at POST30. The change in SpO₂ during high-altitude acclimatization (from HA3 to HA21) was positively correlated with the orienting score at HA21. Vital capacity changes during acute deacclimatization positively correlated with orienting scores at POST7. Attention network functions at the behavioral level did not decline after acute hypoxia exposure compared with baseline. Attention network functions after returning to sea level were improved compared with those during acute hypoxia; additionally, alerting and executive function scores were improved compared with those at baseline. Thus, the speed of physiological adaptation could facilitate the recovery of orienting function during acclimatization and deacclimatization.

Comorbid Cognitive Impairment in Chronic Obstructive Pulmonary Disease (COPD): Current Understanding, Risk Factors, Implications for Clinical Practice, and Suggested Interventions

Cognitive impairment is a common comorbidity in patients with COPD, significantly impacting health and clinical outcomes. Yet it remains under investigated and is largely overlooked. Although the exact cause of cognitive impairment in patients with COPD is still unclear, factors such as hypoxemia, vascular disease, smoking, exacerbation, and physical inactivity have been suggested. While international guidelines recommend identifying comorbidity in patients with COPD, such as cognitive impairment, cognitive assessment is not yet part of the routine assessment. Unidentified cognitive deficits in patients with COPD may have severe impacts on clinical management, resulting in an inability to maintain functional independence, poor self-management, and a greater dropout from pulmonary rehabilitation programs. There is a need to consider cognitive screening as a part of COPD assessment to promote early detection of cognitive impairment. Recognizing cognitive impairment early in the course of the illness allows the development of individualized interventions to meet patients' needs and improve clinical outcomes. Pulmonary rehabilitation should be tailored to cognitively impaired patients with COPD to maximize the benefits and minimize the incompletion rate.

Assessment of incidence of cerebral vascular diseases and prediction of stroke risk in chronic obstructive pulmonary disease patients using multimodal biomarkers

BACKGROUND

Early assessment of cerebrovascular disease in chronic obstructive pulmonary disease (COPD) patients is an important issue for a favorable influence on the quality of life.

METHODOLOGY

This cross-sectional case-control study was conducted on 38 eligible COPD patients (mean age 55.5 ± 11.5, 25 males, and 13 females) and 26 age-/sex-matched healthy controls. All participants were subjected to stroke risk screening instruments that included the Stroke Riskometer™, the Framingham 10-Year Risk Score, the stroke risk screening tool (the Department of Disease Control of Thailand), the My Risk Stroke Calculator, and Q Stroke. Radiologically, diffusion tensor imaging (DTI) and echo-gradient MRI (T2 star) T2 star imaging were done. Color-coded duplex sonography was done. Laboratory investigations included C-reactive protein (CRP), serum amyloid A, plasma fibrinogen level, serum IL6, 8-Isoprostane, vWF and urinary albumin creatinine ratio.

RESULTS

Stroke risk screening instruments revealed a significant increase in COPD patients. DTI showed a significant bilateral reduction in fractional isotropy and a significant bilateral increase in mean diffusivity of white matter through many areas in COPD patients. Patients also had a significant increase of intima-media thickness, presence of atherosclerotic focal thicknesses or plaques on duplex sonography. There was a significant elevation of CRP, serum amyloid A, plasma fibrinogen level, serum IL6, 8-isoprostane, von Willebrand factor (vWF), and urinary albumin creatinine ratio in COPD patients.

CONCLUSION

COPD patients had an increased risk for stroke that could be assessed on stroke risk screening instruments, DTI, T2 star, duplex sonography, and laboratory investigation and could be correlated with the severity of the disease.

Smoking related attention alteration in chronic obstructive pulmonary disease-smoking comorbidity

Background

Chronic obstructive pulmonary disease (COPD) is a respiratory disease that causes a wide range of cognitive impairments. Although COPD-Smoking comorbidity is common, the relationship between smoking and cognitive function in COPD-Smoking comorbidity remains unclear. This study aimed to investigate the effect of smoking on cognitive function like attention in COPD-Smoking patients.

Methods

In this study, we used the Montreal Cognitive Assessment (MoCA) scale and resting-state functional magnetic resonance imaging (fMRI) to explore the effect of smoking on attention in patients with COPD.

Results

Behavioral analysis revealed that among patients with COPD the smokers had a shorter course of COPD and showed a worse attention performance than the non-smokers. Resting-state fMRI analysis revealed that among patients with COPD smokers showed lower regional homogeneity (ReHo) value of the fusiform gyrus than non-smokers. Importantly, the ReHo of the fusiform gyrus is positively associated with attention and mediates the effect of smoking on attention in COPD.

Conclusions

In summary, our study provides behavioral and neurobiological evidence supporting the positive effect of smoking on attention in COPD. This may be helpful for understanding and treating COPD and even other diseases comorbid with smoking.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01964-6.

Emerging Evidence for the Widespread Role of Glutamatergic Dysfunction in Neuropsychiatric Diseases

The monoamine model of depression has long formed the basis of drug development but fails to explain treatment resistance or associations with stress or inflammation. Recent animal research, clinical trials of ketamine (a glutamate receptor antagonist), neuroimaging research, and microbiome studies provide increasing evidence of glutamatergic dysfunction in depression and other disorders. Glutamatergic involvement across diverse neuropathologies including psychoses, neurodevelopmental, neurodegenerative conditions, and brain injury forms the rationale for this review. Glutamate is the brain's principal excitatory neurotransmitter (NT), a metabolic and synthesis substrate, and an immune mediator. These overlapping roles and multiple glutamate NT receptor types complicate research into glutamate neurotransmission. The glutamate microcircuit comprises excitatory glutamatergic neurons, astrocytes controlling synaptic space levels, through glutamate reuptake, and inhibitory GABA interneurons. Astroglia generate and respond to inflammatory mediators. Glutamatergic microcircuits also act at the brain/body interface via the microbiome, kynurenine pathway, and hypothalamus-pituitary-adrenal axis. Disruption of excitatory/inhibitory homeostasis causing neuro-excitotoxicity, with neuronal impairment, causes depression and cognition symptoms via limbic and prefrontal regions, respectively. Persistent dysfunction reduces neuronal plasticity and growth causing neuronal death and tissue atrophy in neurodegenerative diseases. A conceptual overview of brain glutamatergic activity and peripheral interfacing is presented, including the common mechanisms that diverse diseases share when glutamate homeostasis is disrupted.

Associations of Pulmonary Function with MRI Brain Volumes: A Coordinated Multi-Study Analysis

BACKGROUND

Previous studies suggest poor pulmonary function is associated with increased burden of cerebral white matter hyperintensities and brain atrophy among elderly individuals, but the results are inconsistent.

OBJECTIVE

To study the cross-sectional associations of pulmonary function with structural brain variables.

METHODS

Data from six large community-based samples (N = 11,091) were analyzed. Spirometric measurements were standardized with respect to age, sex, height, and ethnicity using reference equations of the Global Lung Function Initiative. Associations of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and their ratio FEV1/FVC with brain volume, gray matter volume, hippocampal volume, and volume of white matter hyperintensities were investigated using multivariable linear regressions for each study separately and then combined using random-effect meta-analyses.

RESULTS

FEV1 and FVC were positively associated with brain volume, gray matter volume, and hippocampal volume, and negatively associated with white matter hyperintensities volume after multiple testing correction, with little heterogeneity present between the studies. For instance, an increase of FVC by one unit was associated with 3.5 ml higher brain volume (95% CI: [2.2, 4.9]). In contrast, results for FEV1/FVC were more heterogeneous across studies, with significant positive associations with brain volume, gray matter volume, and hippocampal volume, but not white matter hyperintensities volume. Associations of brain variables with both FEV1 and FVC were consistently stronger than with FEV1/FVC, specifically with brain volume and white matter hyperintensities volume.

CONCLUSION

In cross-sectional analyses, worse pulmonary function is associated with smaller brain volumes and higher white matter hyperintensities burden.

Factors affecting brain structure in smoking-related diseases: Chronic Obstructive Pulmonary Disease (COPD) and coronary artery disease

Background

Changes in brain structure and cognitive decline occur in Chronic Obstructive Pulmonary Disease (COPD). They also occur with smoking and coronary artery disease (CAD), but it is unclear whether a common mechanism is responsible.

Methods

Brain MRI markers of brain structure were tested for association with disease markers in other organs. Where possible, principal component analysis (PCA) was used to group markers within organ systems into composite markers. Univariate relationships between brain structure and the disease markers were explored using hierarchical regression and then entered into multivariable regression models.

Results

100 participants were studied (53 COPD, 47 CAD). PCA identified two brain components: brain tissue volumes and white matter microstructure, and six components from other organ systems: respiratory function, plasma lipids, blood pressure, glucose dysregulation, retinal vessel calibre and retinal vessel tortuosity. Several markers could not be grouped into components and were analysed as single variables, these included brain white matter hyperintense lesion (WMH) volume. Multivariable regression models showed that less well organised white matter microstructure was associated with lower respiratory function (p = 0.028); WMH volume was associated with higher blood pressure (p = 0.036) and higher C-Reactive Protein (p = 0.011) and lower brain tissue volume was associated with lower cerebral blood flow (p<0.001) and higher blood pressure (p = 0.001). Smoking history was not an independent correlate of any brain marker.

Conclusions

Measures of brain structure were associated with a range of markers of disease, some of which appeared to be common to both COPD and CAD. No single common pathway was identified, but the findings suggest that brain changes associated with smoking-related diseases may be due to vascular, respiratory, and inflammatory changes.

Novel pharmacological strategies to treat cognitive dysfunction in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and currently the 3rd largest cause of death in the world, with approximately 3.23 million deaths per year. Globally, the financial burden of COPD is approximately €82 billion per year and causes substantial morbidity and mortality. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities and viral and bacterial-induced acute exacerbations (AECOPD). Recent clinical studies have shown that cognitive dysfunction is present in up to 60% of people with COPD, with impairments in executive function, memory, and attention, impacting on important outcomes such as quality of life, hospitalisation and survival. The high prevalence of cognitive dysfunction in COPD may also help explain the insufficient adherence to therapeutic plans and strategies, thus worsening disease progression in people with COPD. However, the mechanisms underlying the impaired neuropathology and cognition in COPD remain largely unknown. In this review, we propose that the observed pulmonary oxidative burden and inflammatory response of people with COPD 'spills over' into the systemic circulation, resulting in damage to the brain and leading to cognitive dysfunction. As such, drugs targeting the lungs and comorbidities concurrently represent an exciting and unique therapeutic opportunity to treat COPD and cognitive impairments, which may lead to the production of novel targets to prevent and reverse the debilitating and life-threatening effects of cognitive dysfunction in COPD.

Lung function, COPD and cognitive function: a multivariable and two sample Mendelian randomization study

BACKGROUND

Observational studies show an association between reduced lung function and impaired cognition. Cognitive dysfunction influences important health outcomes and is a precursor to dementia, but treatments options are currently very limited. Attention has therefore focused on identifying modifiable risk factors to prevent cognitive decline and preserve cognition. Our objective was to determine if lung function or risk of COPD causes reduced cognitive function using Mendelian randomization (MR).

METHODS

Single nucleotide polymorphisms from genome wide association studies of lung function and COPD were used as exposures. We examined their effect on general cognitive function in a sample of 132,452 individuals. We then performed multivariable MR (MVMR), examining the effect of lung function before and after conditioning for covariates.

RESULTS

We found only weak evidence that reduced lung function (Beta - 0.002 (SE 0.02), p-value 0.86) or increased liability to COPD (- 0.008 (0.008), p-value 0.35) causes lower cognitive function. MVMR found both reduced FEV1 and FVC do cause lower cognitive function, but that after conditioning for height (- 0.03 (0.03), p-value 0.29 and - 0.01 (0.03) p-value 0.62, for FEV1 and FVC respectively) and educational attainment (- 0.03 (0.03) p-value 0.33 and - 0.01 (0.02), p-value 0.35) the evidence became weak.

CONCLUSION

We did not find evidence that reduced lung function or COPD causes reduced cognitive function. Previous observational studies are probably affected by residual confounding. Research efforts should focus on shared risk factors for reduced lung function and cognition, rather than lung function alone as a modifiable risk factor.

Change of Serum Inflammatory Cytokines Levels in Patients With Chronic Obstructive Pulmonary Disease, Pneumonia and Lung Cancer

Objective:

This study aimed to investigate the serum inflammatory cytokines levels in patients with COPD, pneumonia and lung cancer, and assess the correlation between the levels of inflammatory cytokines levels and development of these diseases.

Methods:

Two hundred thirty-two patients including 114 patients with pneumonia, 76 patients with chronic obstructive pulmonary disease (COPD) and 42 patients with lung cancer, and 62 age-matched healthy volunteers as controls were enrolled. The pro-inflammatory cytokine IL-6, IL-2, IFN-γ, TNF-α, anti-inflammatory cytokines IL-4 and IL-10 in serum were analyzed by flow cytometry microsphere array (CBA).

Results:

We found that the levels of TNF-α and IL-10 in patients with lung cancer, COPD and pneumonia were significantly higher than control group. The IL-6 in the lung cancer group were significantly increased compared with the controls and COPD group, pneumonia group. IFN-γ and IL-2 levels were lower in lung cancer compared with controls and COPD group, pneumonia group. TNF-α, IL-4 and IL-10 levels were increased in patients with COPD and pneumonia compared with controls. In addition, the concentrations of IFN-γ and IL-6 were increased in acute exacerbation COPD (AECOPD) group compared with stable COPD group.

Conclusion:

In conclusion, elevated TNF-α and IL-10 levels in serum may be related with lung diseases including lung cancer, COPD and pneumonia. Additionally, IFN-γ and IL-6 might be potential biomarkers for the further deterioration of lung disease patients. The increased concentrations of IFN-γ and IL-6 might be used to predict the exacerbation of COPD.

The effect of acupoint application of traditional Chinese medicine for the treatment of chronic obstructive pulmonary disease: A protocol for systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a public threat, leading to progressive physical activity and poor quality of life. Although modern medicine has excellent achievement of COPD, the recurrence rate of stable COPD and the mortality of acute exacerbation COPD remain high. As one of the external therapy of traditional Chinese medicine, acupoint application has been treated COPD in China for a long time. Nevertheless, study evaluating the effect of acupoint application for COPD could not satisfy needs for clinic.

METHOD

Randomized controlled trials meeting the inclusion criteria will be collected by the 2 reviewers. We choose the following electronic databases of Web of Science, Pub Med, EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wan Fang, Chinese Scientific Journals Database, and Chinese Biomedical Database as our retrieval tool. The retrieval time was from inception to March 2020. The key to evaluation criteria is total clinical efficacy rate and lung function will be measured. Secondary outcomes include assessment scales and adverse reactions. The studies extracted will be assessed. The merging analysis will be carried out by Review Manager Software.

RESULT

A scientific evidence of efficacy and safety of acupoint application for COPD will be found.

CONCLUSION

The evaluation of the efficacy and safety of acupoint application for COPD will be presented.

INPLASY REGISTRATION NUMBER

INPLASY202090023.

Chronic Obstructive Pulmonary Disease: Proprioception Exercises as an Addition to the Rehabilitation Process

Respiratory rehabilitation in patients with chronic obstructive pulmonary disease (COPD) is recognized as a cornerstone for the therapeutic path. Physiotherapy involves physical activity with aerobic and anaerobic exercises, which can improve the patient's symptomatic picture, such as motor function, emotional status (depression and anxiety), and improve the pain perception. The training of proprioception is not included in the structure of the exercises proposed by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). The training of proprioception is a very useful strategy for stimulating the cerebellum, a neurological suffering area in patients with COPD. The cerebellum sorts information about pain and emotions, as well as motor stimuli. The article discusses the need to introduce proprioception in respiratory rehabilitation protocols, highlighting the neurological relationships with the management of comorbidities.