Symptom profiles and inflammatory markers in moderate to severe COPD

A Pilot Study on Proteomic Predictors of Mortality in Stable COPD

Chronic Obstructive Pulmonary Disease (COPD) is the third leading cause of global mortality. Despite clinical predictors (age, severity, comorbidities, etc.) being established, proteomics offers comprehensive biological profiling to obtain deeper insights into COPD pathophysiology and survival prognoses. This pilot study aimed to identify proteomic footprints that could be potentially useful in predicting mortality in stable COPD patients. Plasma samples from 40 patients were subjected to both blind (liquid chromatography-mass spectrometry) and hypothesis-driven (multiplex immunoassays) proteomic analyses supported by artificial intelligence (AI) before a 4-year clinical follow-up. Among the 34 patients whose survival status was confirmed (mean age 69 ± 9 years, 29.5% women, FEV1 42 ± 15.3% ref.), 32% were dead in the fourth year. The analysis identified 363 proteins/peptides, with 31 showing significant differences between the survivors and non-survivors. These proteins predominantly belonged to different aspects of the immune response (12 proteins), hemostasis (9), and proinflammatory cytokines (5). The predictive modeling achieved excellent accuracy for mortality (90%) but a weaker performance for days of survival (Q2 0.18), improving mildly with AI-mediated blind selection of proteins (accuracy of 95%, Q2 of 0.52). Further stratification by protein groups highlighted the predictive value for mortality of either hemostasis or pro-inflammatory markers alone (accuracies of 95 and 89%, respectively). Therefore, stable COPD patients' proteomic footprints can effectively forecast 4-year mortality, emphasizing the role of inflammatory, immune, and cardiovascular events. Future applications may enhance the prognostic precision and guide preventive interventions.

Biomarkers of Inflammation and Longitudinal Evaluation of Lung Function, Physical Activity, and Grip Strength: A Secondary Analysis in the CASCADE Study

Rationale

Physical activity, lung function, and grip strength are associated with exacerbations, hospitalizations, and mortality in people with chronic obstructive pulmonary disease (COPD). We tested whether baseline inflammatory biomarkers were associated with longitudinal outcomes of these physiologic measurements.

Methods

The COPD Activity: Serotonin Transporter, Cytokines, and Depression (CASCADE) study was a prospective observational study of individuals with COPD. A total of 14 inflammatory biomarkers were measured at baseline. Participants were followed for 2 years. We analyzed associations between baseline biomarkers and forced expiratory volume in 1 second (FEV1), physical activity, and grip strength. We used a hierarchical hypothesis testing procedure to reduce type I error. We used Pearson correlations to test associations between baseline biomarkers and longitudinal changes in the outcomes of interest. We used Fisher's linear discriminant analysis to test if linear combinations of baseline biomarkers predict rapid FEV1 decline. Finally, we used linear mixed modeling to test associations between baseline biomarkers and outcomes of interest at baseline, year 1, and year 2; models were adjusted for age, smoking status, baseline biomarkers, and FEV1.

Results

A total of 302 participants (age 67.5 ± 8.5 years, 19.5% female, 28.5% currently smoking) were included. Baseline biomarkers were not associated with longitudinal changes in grip strength, physical activity, or rapid FEV1 decline. Higher interleukin-6 and C-reactive protein were associated with lower physical activity at baseline and these relationships persisted at year 1 and year 2.

Conclusion

Baseline inflammatory biomarkers did not predict changes in lung function or physical activity, but higher inflammatory biomarkers were associated with persistently low levels of physical activity.

COPD: systemic proteomic profiles in frequent and infrequent exacerbators

Background

Some patients with COPD suffer frequent exacerbations (FE). We hypothesised that their systemic proteomic profile would be different from that of non-frequent exacerbators (NFE). The objective of the present study was to contrast the systemic proteomic profile in FE versus NFE. As a reference, we also determined the systemic proteomic profile of healthy controls (HC) and COPD patients during an actual episode of exacerbation (AE).

Methods

In the analysis we included 40 clinically stable COPD patients (20 FE and 20 NFE), and 20 HC and 10 AE patients. Their plasma samples were analysed by combining two complementary proteomic approaches: label-free liquid chromatography-tandem mass spectrometry and multiplex immunoassays. Gene Ontology annotation, pathway enrichment and network analyses were used to investigate molecular pathways associated with differentially abundant proteins/peptides (DAPs).

Results

Compared with HC, we identified 40 DAPs in FE, 10 in NFE and 63 in AE. Also compared to HC, pathway functional and protein-protein network analyses revealed dysregulation of inflammatory responses involving innate and antibody-mediated immunity in COPD, particularly in the FE group, as well as during an AE episode. Besides, we only identified alterations in the complement and coagulation cascades in AE.

Conclusion

There are specific plasma proteome profiles associated with FE, which are partially shared with findings observed during AE, albeit others are uniquely present during the actual episode of AE.

Inflammatory Markers and Fatigue in Individuals With Moderate to Severe Chronic Obstructive Pulmonary Disease

BACKGROUND

Fatigue, a prevalent complex symptom among patients with chronic obstructive pulmonary disease (COPD), is considered an important clinical indicator of disease severity. However, the underlying mechanisms of COPD-related fatigue are not fully understood.

OBJECTIVES

This analysis explored the relationships between peripheral inflammatory markers and COPD-related fatigue in people with moderate to severe COPD.

METHODS

This is a secondary analysis of a longitudinal observational study of individuals with COPD examining the biological causes and functional consequences of depression. The data used in this study were collected at baseline. Systemic inflammation markers included C-reactive protein (CRP) and three pro-inflammatory cytokines consisting of interleukin-6 (IL-6), IL-8, and tumor necrosis factor-α. COPD-related fatigue was self-reported using the Chronic Respiratory Questionnaire. Covariates included age; gender; smoking status; disease severity; symptoms of depression, anxiety, and pain; and social support. Multivariable linear regression analyses were conducted.

RESULTS

The sample included 300 adults living with COPD; 80% were male, and the average age was 67.6 years. Modest correlations were found between two systemic inflammatory markers (CRP and IL-8) and COPD-related fatigue. CRP was the only inflammatory marker significantly associated with fatigue symptoms after adjusting for covariates in multivariable analyses. Depression, pain, and education level were also significant predictors of COPD-related fatigue.

DISCUSSION

The findings suggest that altered immune response based on CRP may contribute to COPD-related fatigue. Management of depression and pain may work as an effective treatment strategy for COPD-related fatigue. Further longitudinal studies with a broader range of inflammatory markers and multidimensional measures of fatigue symptoms are warranted.

Factors Related to Fatigue and Physical Function in COPD: A Secondary Analysis Using National Survey Data

Fatigue in chronic obstructive pulmonary disease (COPD) is debilitating and associated with considerable morbidity. The aim of this study is to present a model based on the Theory of Unpleasant Symptoms of physiologic, psychologic, and situational factors with COPD-related fatigue and the relationship with physical functioning. This study used data collected from Wave 2 (2010-2011) of the National Social, Health, and Aging Project (NSHAP). A total of 518 adults with self-reported COPD were included in this study. Path analysis was used for hypothesis testing. Depression was the only psychologic factor found to have a direct relation to both fatigue (β = 0.158, p < .001) and physical function (β = -0.131, p = .001). Factors related to physical function included fatigue, depression, sleep, loneliness, and pain. Additionally, fatigue was indirectly associated with physical function via depression (β = -0.064, p = .012). These findings suggest avenues for future research on predictors of COPD-related fatigue in relation to physical functioning.

COPD-Related Fatigue: A Scoping Review

Millions of people worldwide have chronic obstructive pulmonary disease (COPD), and one of the most common and troublesome symptoms that must be managed is fatigue. While there are existing interventions to address COPD-related fatigue, not all patients experience benefit. A better understanding of the factors associated with COPD-fatigue could elucidate new approaches to address COPD-related fatigue, thereby offering relief to a greater number of patients. The purpose of this review was to identify the physiologic, psychologic, and situational factors associated with COPD-related fatigue. A total of four databases, PubMed, CINAHL, Scopus, and Google Scholar, were searched. Those that were peer reviewed, in English, and published between 2000 and 2021, were included in the review. A total of 25 articles were included in this scoping review. The following factors were related to fatigue in COPD: dyspnea, pain, anxiety, depression, and sleep. Fatigue is a debilitating symptom with factors influential to the symptom and outcomes. Research is indicated to explore targeted and personalized interventions addressing the factors related to fatigue to mitigate this widespread symptom.

Symptom Classes in Decompensated Liver Disease

BACKGROUND & AIMS

Patients with decompensated liver disease have been categorized by disease severity. This analysis sought to classify patients with end-stage liver disease based on symptoms rather than disease state and to identify distinct severity classes of physical and psychological symptoms.

METHODS

Patients with a model for end-stage liver disease-sodium score of 15 or higher were recruited from liver clinics in 2 health care organizations. They completed the Condensed Memorial Symptom Assessment Scale, Revised Ways of Coping Checklist, Patient Health Questionnaire, Life Orientation Test-Revised, and the Short-Form Health Survey. Cross-sectional data were analyzed using latent class mixture modeling.

RESULTS

The sample (N = 191; age, 56.6 ± 11.1 y; 33.5% ETOH; 28.3% nonalcoholic fatty liver disease; 13.1% autoimmune/primary biliary cholangitis/primary sclerosing cholangitis) was predominantly male (64.2%), Child-Turcotte-Pugh class C (49.5%), with an average model for end-stage liver disease-sodium score of 18.7 ± 4.9. Three distinct classes of symptoms were identified, as follows: mild (26.7%), moderate (41.4%), or severe (31.9%) symptoms. Symptom classes were independent of disease severity and demographic characteristics, except age. All Condensed Memorial Symptom Assessment Scale symptoms and Patient Health Questionnaire scores were significantly different across the 3 classes (P < .05). The symptom classes also differed significantly in physical and mental quality of life, optimism, and avoidance coping behaviors (all P < .001).

CONCLUSIONS

Patient-reported symptom severity occurred independent of disease severity, contrary to common assumptions. Focusing on the moderate and severe symptom classes as well as patient history of end-stage liver disease complications may enhance providers' ability to improve symptom management for this population.

Grupo de síntomas de enfermedad pulmonar obstructiva crónica y cuidados paliativos: una revisión sistemática

La enfermedad pulmonar obstructiva crónica (EPOC) es una entidad patológica que se caracteriza por una serie de manifestaciones físicas persistentes como tos, fatiga, disnea y producción de esputo; síntomas que generan malestar en el paciente desde el momento del diagnóstico y que, al ser una enfermedad irreversible por el daño tisular que causa, progresivamente va incidiendo de manera negativa en la calidad de vida. De otra parte, se ha reportado presencia de síntomas psicológicos como depresión, inseguridad, ansiedad y alteraciones emocionales en los pacientes diagnosticados con EPOC. Así mismo, los pacientes con este diagnóstico tienden a desarrollar comportamientos que alteran sus relaciones sociales familiares y laborales, por cuanto tienden a aislarse debido a la sintomatología, especialmente física. La situación planteada genera la necesidad de desarrollar un trabajo de investigación con el objetivo de reconocer el clúster de síntomas físicos, psicológicos y sociales de los pacientes diagnosticados con EPOC, e identificar si se plantea un abordaje desde la atención paliativa. El estudio se desarrolló mediante una revisión sistemática de literatura en la que se identificaron 1776 artículos, de los que se evaluaron 41 para la identificación del clúster de síntomas. Se identificó el binomio disnea y tos, fatiga y expectoración como el clúster de síntomas físicos; la depresión y la ansiedad constituyen el clúster de síntomas psicológicos, y el impacto en la calidad de vida y la percepción de aislamiento o exclusión social.

Potential Explanatory Factors for the Concurrent Experience of Dyspnea and Pain in Patients with COPD

Previous research has identified unexpectedly strong associations between dyspnea and pain, but the reasons remain unclear. Ascertaining the underlying biological and psychological mechanisms might enhance the understanding of the experience of both conditions, and suggest novel treatments. We sought to elucidate whether demographic factors, disease severity, psychological symptoms and biomarkers might account for the association between pain and dyspnea in individuals with COPD. We analyzed data from 301 patients with COPD who were followed in a prospective longitudinal observational study over 2 years. Measures included self-reported dyspnea and pain, pulmonary function tests, serum levels of inflammatory cytokines, measures of physical deconditioning, and scales for depression and anxiety. Analyses involved cross-sectional and longitudinal linear regression models. Pain and dyspnea were strongly correlated cross-sectionally (r = 0.77, 95% CI 0.72-0.82) and simultaneously across time (r = 0.42, 95% CI 0.28-0.56). Accounting for any of the other health factors only slightly mitigated the associations. Symptoms of pain and dyspnea thus may be fundamentally linked in COPD, rather than being mediated by common biological, psychological, or functional factors. From the patient's perspective, pain and dyspnea may be part of the same essential experience. It is possible that treatments for one condition would improve the other.

A Study of Various Predictors of COPD-Related Fatigue (COPD-RF) and its Correlation with other Established Outcome Parameters in COPD

Background

Over the years approach to COPD has changed. The focus of evaluation is shifting from physiological outcome parameters to patient centered outcomes. COPD-RF is one such patient related outcome that is of considerable importance to the patients as fatigue is the second common distressing symptom in COPD & is a major concern for the patients. COPD-RF is not only a reflection of airflow limitation severity but also a result of psychological, behavioral, and physical factors. Therefore, identification of markers which determine COPD RF is essential to improve patient management. This study aims to identify the predictors of COPD Related fatigue (COPD-RF) and its correlation with other outcome tools like FEV1, 6-minute walk distance (6MWD), MMRC grade, BODE index & inflammatory markers.

Methodology

50 stable COPD patients were taken in the study. MMRC grade, FEV1, 6MWD, BODE index, CRP level and sputum neutrophil % obtained. COPD-RF was assessed using 13 item (FACIT-fatigue) questionnaire. The correlation analysis was done by spearman rank correlation and ANOVA. Predictors of COPD-RF were identified by multiple linear regression.

Result

Mean age of the population was 56.53 ± 9.29. All GOLD category of severity was equally represented in the study group. The fatigue score showed significant correlation with inflammatory markers (CRP-r=-0.675; neutrophil%- r=-0.485) & 6MWD (r=-.428). Categorical variables (MMRC, FEV1 GOLD stages & BODE quartiles) also showed significant difference of fatigue among categories. BODE index & serum CRP were identified as the statistically significant predictors of fatigue, suggesting COPD-RF could reflect severity of underlying pathophysiologic process i.e. systemic inflammation.

Conclusion

BODE index and CRP levels are the two important surrogate markers that predicts COPR-RF implying a role of systemic inflammation in the pathogenesis of fatigue. Also, COPD-RF could be an indicator of long-term prognosis of the disease & should be routinely evaluated during COPD assessment.

Serotonin transporter gene polymorphisms and depressive symptoms in patients with chronic obstructive pulmonary disease

Background: We examined the relationship between polymorphisms in the promoter region of the serotonin transport (SERT) gene (5-HTTLPR, short 'S' and long 'L' alleles) and in intron 2 variable number tandem repeat (STin2VNTR, 9, 10, or 12-repeat alleles) with depression or anxiety in patients with COPD.Methods: 302 patients with moderate to severe COPD participated in SERT study. History and number of prior depressive episodes were measured using the Structured Clinical Interview for Depression; Hospital Anxiety Depression Scale (HAD) depression ≥8 or a Patient Health Questionnaire-9 (PHQ-9) >,10.Results: 240 (80%) male sample had a mean age of 68.0 years. Current depression was 22% (HAD) or 21% (PHQ-9), anxiety was 25% (HAD), and suicidal ideation (6%). 5-HTTLPR or STin2 VNTR genotypes were not associated with current depressive or anxiety symptoms. The mean number of prior depressive episodes was higher for patients with the 5-HTTLPR genotype S/S or S/L compared with L/L (4.4 ± 6.1; 5.3 ± 6.8; 4.0 ± 6.1, p < 0.001) and with STin2VNTR high-risk genotype (9/12 or 12/12), medium risk (9/10 or 10/12) compared to low risk (10/10) genotypes (5.1 ± 6.8; 4.9 ± 6.7; 2.7 ± 4.5, p < 0.001).Conclusions: SERT 5-HTTLPR and STin2-VNTR polymorphisms were not associated with current depressive and anxiety symptoms, but the high-risk STin2-VNTR genotypes and S/L were associated with the number of prior depressive episodes.

Systemic Cytokine Profiles of CD4+ T Lymphocytes Correlate with Clinical Features and Functional Status in Stable COPD

Aims

To evaluate the expressions of intracellular cytokines in CD4+ T lymphocytes and to investigate the correlation between biomarker expressions and clinical and functional characteristics of stable COPD patients.

Patients and Methods

Peripheral blood was collected from 36 COPD patients, and the expression of cytokines (IL-8, IL-13, IL-17, IL-6, IL-2, IL-10, and TNF-α) in T lymphocytes CD4 + was investigated. In addition, lung function, dyspnea symptoms, quality of life, vital signs, body composition, level of physical activity, peripheral muscle strength, and functional capacity were assessed.

Results

Individuals with greater bronchial obstruction present a higher proportion of CD4 + IL-2 + lymphocytes compared to individuals with less severe bronchial obstruction. We found a positive correlation between the expression of the cytokines IL-13, IL-17, IL-6, IL-2, IL-10, and TNF-α in CD4+ T lymphocytes. In addition, we found a positive correlation between CD4+ IL-10+ T lymphocytes and lower limb muscle strength and a negative correlation between CD4+ IL-8+ T lymphocytes and peripheral oxygen saturation and steps per day.

Conclusion

Systemic CD4+IL-2+, IL-8+, and IL-10+ T lymphocytes presented a correlation with clinical characteristics and functional status in stable COPD.

Identification of Symptom Clusters and Their Influencing Factors in Subgroups of Chinese Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease

CONTEXT

Limited studies have identified symptom clusters (SCs) and their risk factors and the relationships with inflammatory biomarkers in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

OBJECTIVES

In this study, we aimed to investigate SCs in patients with AECOPD and explore their influencing factors and relationships with inflammatory biomarkers.

METHODS

Data were collected with sociodemographic and disease information questionnaires, and symptoms were measured with the revised Memorial Symptom Assessment Scale. SCs were extracted through exploratory factor analysis. Logistic regression analysis was conducted to explore the risk factors of SCs.

RESULTS

A total of 151 patients were recruited. Two SCs, namely, emotional and respiratory functional SCs, were identified. Logistic regression analysis showed that individuals with high C-reactive protein level, Charlson Comorbidity Index score, and high modified Medical Research Council Dyspnea Scale score were more likely to belong to the high-severity symptom subgroup than to the low-severity symptom group in the emotional SC. The patients with a low body mass index and without or lax inhaled drug therapy exhibited highly prominent predictors of membership in the high-severity symptom group of the respiratory functional SC.

CONCLUSION

Symptoms experienced by patients with AECOPD were grouped into specific clusters. Targeted interventions should be performed based on SCs, and influencing factors and biological mechanisms should be considered when providing individualized approaches and interventions.

Frailty in Chronic Obstructive Pulmonary Disease and Risk of Exacerbations and Hospitalizations

Background

Frailty is a complex clinical syndrome associated with vulnerability to adverse health outcomes. While frailty is thought to be common in chronic obstructive pulmonary disease (COPD), the relationship between frailty and COPD-related outcomes such as risk of acute exacerbations of COPD (AE-COPD) and hospitalizations is unclear.

Purpose

To examine the association between physical frailty and risk of acute exacerbations, hospitalizations, and mortality in patients with COPD.

Methods

A longitudinal analysis of data from a cohort of 280 participants was performed. Baseline frailty measures included exhaustion, weakness, low activity, slowness, and undernutrition. Outcome measures included AE-COPD, hospitalizations, and mortality over 2 years. Negative binomial regression and Cox proportional hazard modeling were used.

Results

Sixty-two percent of the study population met criteria for pre-frail and 23% were frail. In adjusted analyses, the frailty syndrome was not associated with COPD exacerbations. However, among the individual components of the frailty syndrome, weakness measured by handgrip strength was associated with increased risk of COPD exacerbations (IRR 1.46, 95% CI 1.09–1.97). The frailty phenotype was not associated with all-cause hospitalizations but was associated with increased risk of non-COPD-related hospitalizations.

Conclusion

This longitudinal cohort study shows that a high proportion of patients with COPD are pre-frail or frail. The frailty phenotype was associated with an increased risk of non-COPD hospitalizations but not with all-cause hospitalizations or COPD exacerbations. Among the individual frailty components, low handgrip strength was associated with increased risk of COPD exacerbations over a 2-year period. Measuring handgrip strength may identify COPD patients who could benefit from programs to reduce COPD exacerbations.

Serum IgG Levels and Risk of COPD Hospitalization: A Pooled Meta-analysis

BACKGROUND

Hypogammaglobulinemia (serum IgG levels < 7.0 g/L) has been associated with increased risk of COPD exacerbations but has not yet been shown to predict hospitalizations.

RESEARCH QUESTION

To determine the relationship between hypogammaglobulinemia and the risk of hospitalization in patients with COPD.

STUDY DESIGN AND METHODS

Serum IgG levels were measured on baseline samples from four COPD cohorts (n = 2,259): Azithromycin for Prevention of AECOPD (MACRO, n = 976); Simvastatin in the Prevention of AECOPD (STATCOPE, n = 653), Long-Term Oxygen Treatment Trial (LOTT, n = 354), and COPD Activity: Serotonin Transporter, Cytokines and Depression (CASCADE, n = 276). IgG levels were determined by immunonephelometry (MACRO; STATCOPE) or mass spectrometry (LOTT; CASCADE). The effect of hypogammaglobulinemia on COPD hospitalization risk was evaluated using cumulative incidence functions for this outcome and deaths (competing risk). Fine-Gray models were performed to obtain adjusted subdistribution hazard ratios (SHR) related to IgG levels for each study and then combined using a meta-analysis. Rates of COPD hospitalizations per person-year were compared according to IgG status.

RESULTS

The overall frequency of hypogammaglobulinemia was 28.4%. Higher incidence estimates of COPD hospitalizations were observed among participants with low IgG levels compared with those with normal levels (Gray's test, P < .001); pooled SHR (meta-analysis) was 1.29 (95% CI, 1.06-1.56, P = .01). Among patients with prior COPD admissions (n = 757), the pooled SHR increased to 1.58 (95% CI, 1.20-2.07, P < .01). The risk of COPD admissions, however, was similar between IgG groups in patients with no prior hospitalizations: pooled SHR = 1.15 (95% CI, 0.86-1.52, P =.34). The hypogammaglobulinemia group also showed significantly higher rates of COPD hospitalizations per person-year: 0.48 ± 2.01 vs 0.29 ± 0.83, P < .001.

INTERPRETATION

Hypogammaglobulinemia is associated with a higher risk of COPD hospital admissions.

Identification of Acute Kidney Injury Subphenotypes with Differing Molecular Signatures and Responses to Vasopressin Therapy

RATIONALE

Currently, no safe and effective pharmacologic interventions exist for acute kidney injury (AKI). One reason may be that heterogeneity exists within the AKI population, thereby hampering the identification of specific pathophysiologic pathways and therapeutic targets.

OBJECTIVE

The aim of this study was to identify and test whether AKI subphenotypes have prognostic and therapeutic implications.

METHODS

First, latent class analysis methodology was applied independently in two critically ill populations (discovery [n = 794] and replication [n = 425]) with AKI. Second, a parsimonious classification model was developed to identify AKI subphenotypes. Third, the classification model was applied to patients with AKI in VASST (Vasopressin and Septic Shock Trial; n = 271), and differences in treatment response were determined. In all three populations, AKI was defined using serum creatinine and urine output.

MEASUREMENTS AND MAIN RESULTS

A two-subphenotype latent class analysis model had the best fit in both the discovery (P = 0.004) and replication (P = 0.004) AKI groups. The risk of 7-day renal nonrecovery and 28-day mortality was greater with AKI subphenotype 2 (AKI-SP2) relative to AKI subphenotype 1 (AKI-SP1). The AKI subphenotypes discriminated risk for poor clinical outcomes better than the Kidney Disease: Improving Global Outcomes stages of AKI. A three-variable model that included markers of endothelial dysfunction and inflammation accurately determined subphenotype membership (C-statistic 0.92). In VASST, vasopressin compared with norepinephrine was associated with improved 90-day mortality in AKI-SP1 (27% vs. 46%, respectively; P = 0.02), but no significant difference was observed in AKI-SP2 (45% vs. 49%, respectively; P = 0.99) and the P value for interaction was 0.05.

CONCLUSIONS

This analysis identified two molecularly distinct AKI subphenotypes with different clinical outcomes and responses to vasopressin therapy. Identification of AKI subphenotypes could improve risk prognostication and may be useful for predictive enrichment in clinical trials.

Gulf War Illness-associated increases in blood levels of interleukin 6 and C-reactive protein: biomarker evidence of inflammation

OBJECTIVE

Gulf War Illness is a chronic multisymptom disorder severely impacting the health and well-being of many Veterans of the 1990-1991 Gulf War. Symptoms that define the disease include pain, fatigue, mood and memory impairments, gastrointestinal problems, lung disorders, and skin rashes. In our previous biomarker study, we discovered Gulf War Illness-associated proinflammatory blood biomarkers. Therefore, we hypothesized that chronic inflammation causes the symptoms that define this disorder. Testing the chronic inflammation hypothesis is the objective of this study.

RESULTS

The biomarker fingerprint of Gulf War Illness is the end-product of a cascade of proinflammatory cytokine signals. In particular, the observed increase in C-reactive protein predicts a corresponding increase in interleukin 6, the cytokine that stimulates hepatocytes to produce C-reactive protein. Therefore, in this study we measured potential upstream cytokine signals in plasma samples from Gulf War Veterans. As predicted, a positive correlation between interleukin 6 and C-reactive protein was observed.

Telomere length in COPD: Relationships with physical activity, exercise capacity, and acute exacerbations

RATIONALE

Shorter leukocyte telomere length (LTL) is associated with reduced health-related quality of life and increased risk for acute exacerbations (AEs) and mortality in chronic obstructive pulmonary disease (COPD). Increased physical activity and exercise capacity are associated with reduced risk for AEs and death. However, the relationships between LTL and physical activity, exercise capacity, and AEs in COPD are unknown.

METHODS

Data from 3 COPD cohorts were examined: Cohort 1 (n = 112, physical activity intervention trial), Cohorts 2 and 3 (n = 182 and 294, respectively, separate observational studies). Subjects completed a 6-minute walk test (6MWT) and provided blood for LTL assessment using real-time PCR. Physical activity was measured as average daily step count using an accelerometer or pedometer. Number of self-reported AEs was available for 1) the year prior to enrollment (Cohorts 1 and 3) and 2) prospectively after enrollment (all cohorts). Multivariate models examined associations between LTL and average daily step count, 6MWT distance, and AEs.

RESULTS

A significant association between longer LTL and increased 6MWT distance was observed in the three combined cohorts (β = 3x10-5, p = 0.045). No association between LTL and average daily step count was observed. Shorter LTL was associated with an increased number of AEs in the year prior to enrollment (Cohorts 1 and 3 combined, β = -1.93, p = 0.04) and with prospective AEs (Cohort 3, β = -1.3388, p = 0.0003).

CONCLUSIONS

Among COPD patients, increased LTL is associated with higher exercise capacity, but not physical activity. Shorter LTL was associated with AEs in a subgroup of cohorts.

Effects of Glutathione S-Transferase Gene Polymorphisms and Antioxidant Capacity per Unit Albumin on the Pathogenesis of Chronic Obstructive Pulmonary Disease

OBJECTIVES

To study the effects of GSTM1, GSTT1 gene polymorphisms, and organism antioxidant capacity and related indicators such as antioxidant capacity per unit of albumin (AC/ALB) on chronic obstructive pulmonary disease (COPD).

METHODS

Using polymerase chain reaction technology, GSTM1 and GSTT1 gene polymorphisms were detected in 33 COPD patients and 33 healthy people. The total antioxidant capacity (TAC) found in serum was determined using the I₂/KI potentiometric, KMnO₄ microtitration, and H₂O₂ potentiometric methods. The AC/ALB was defined as the TAC divided by the serum albumin concentration. Logistic regression analysis was carried out with biochemical screening indices, which was found to be closely related with the incidence of COPD.

RESULTS

The GSTM1 and GSTT1 gene deletion rate in the COPD group was significantly higher than that in the control group (P < 0.05). The differences in serum TAC between the COPD and control groups, GSTM1 (+) and GSTM1 (-) groups, and GSTT1 (+) and GSTT1 (-) groups were statistically significant (P < 0.001). In addition, there was a significant difference in the AC/ALB between the COPD and control groups (P < 0.05). Logistic regression analysis showed that the incidence of COPD was closely related to the AC/ALB (P < 0.05).

CONCLUSIONS

GSTM1 and GSTT1 gene polymorphisms are closely correlated with the pathogenesis of COPD, while the AC/ALB plays a decisive role in the occurrence and development of COPD.