Variability of plasma IL-6 and crosslinked fibrin dimers over time in community dwelling elderly subjects

Coagulation and Inflammation in COVID-19: Reciprocal Relationship between Inflammatory and Coagulation Markers

The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), formerly known as 2019-nCoV. Numerous cellular and biochemical issues arise after COVID-19 infection. The severe inflammation that is caused by a number of cytokines appears to be one of the key hallmarks of COVID-19. Additionally, people with severe COVID-19 have coagulopathy and fulminant thrombotic events. We briefly reviewed the COVID-19 disease at the beginning of this paper. The inflammation and coagulation markers and their alterations in COVID-19 illness are briefly discussed in the parts that follow. Next, we talked about NETosis, which is a crucial relationship between coagulation and inflammation. In the end, we mentioned the two-way relationship between inflammation and coagulation, as well as the factors involved in it. We suggest that inflammation and coagulation are integrated systems in COVID-19 that act on each other in such a way that not only inflammation can activate coagulation but also coagulation can activate inflammation.

Soluble TNFR1 has greater reproducibility than IL-6 for the assessment of chronic inflammation in older adults: the case for a new inflammatory marker in aging

Chronic inflammatory pathway activation, commonly referred to as "Inflammaging" or chronic inflammation (CI), is associated with frailty, cognitive and functional decline, and other causes of health span decline in older adults. We investigated the variability of candidate serum measures of CI among community-dwelling older adults selected for mild low-grade inflammation. We focused on serum cytokines known to be highly predictive of adverse health outcomes in older adults (sTNFR1, IL-6) during a short-term (weeks) and medium-term (months) follow-up, as well as immune markers that are less studied in aging but reflect other potentially relevant domains such as adaptive immune activation (sCD25), innate immune activation (sCD14 and sCD163), and the inflammation-metabolism interface (adiponectin/Acrp30) during short-term (weeks) follow up. We found that sTNFR1 was more reproducible than IL-6 over a period of weeks and months short-term and medium-term. The intra-class correlation coefficient (ICC) for sTNFR1 was 0.95 on repeated measures over 6 weeks, and 0.79 on repeated measures with mean interval of 14 weeks, while the ICC for IL-6 was 0.52 over corresponding short-term and 0.67 over corresponding medium-term follow-up. This suggests that sTNFR1 is a more reliable marker of CI than IL-6. This study provides new insights into the reproducibility of serum markers of CI in older adults. The findings suggest that sTNFR1 may be a better marker of CI than IL-6 in this population. Further studies are needed to confirm these findings and to investigate the clinical utility of sTNFR1 in older adults.

Diagnostic performance and predictive value of D-dimer testing in patients referred to the emergency department for suspected myocardial infarction

PURPOSE

The study sought to assess the performance of D-dimer testing for the diagnosis of acute coronary syndrome (ACS) and prediction of outcomes in patients admitted for suspected myocardial infarction (MI).

RESULTS

A total of 3,557 patients with suspected ACS presenting to a single center with a broad range of symptoms including atypical chest pain were retrospectively recruited between 02/2012-01/2019. Of the study cohort, 435 patients had unstable angina (UA), 420 non-ST-segment elevation myocardial infarction (NSTEMI), 22 ST-segment elevation myocardial infarction (STEMI), and 2,680 non-coronary chest pain. Plasma D-dimer concentrations in patients with hs-cTnT >14 ng/L differed significantly from those with hs-cTnT <14 ng/L (1.5 ± 3.6 mg/L vs. 0.5 ± 0.8 mg/L; p<0.0001). Positive predictive value for a final diagnosis of ACS increased proportionally to rising D-dimer concentrations. The area under the curve (AUC) to discriminate STEMI from non-coronary chest pain (AUC 0.729, 95% confidence interval [CI] 0.71-0.75) was moderate and differed not significantly to UA (AUC 0.595, 95% CI 0.58-0.61; p=0.0653). During a median follow-up of 29 months, higher D-dimer was associated with a significantly increased risk of recurrent MI (quartile 4 vs. 1: hazard ratio [HR], 6.9 [95% CI 1.2-39.9]; p<0.0001) and higher all-cause mortality (HR, 17.4 [95% CI 4.3-69.9]; p<0.0001). D-dimer was an independent predictor of all-cause mortality (p<0.0001) and subsequent MI events (p=0.0333).

CONCLUSIONS

D-dimer testing revealed great potential to provide independent prognostic information on recurrent MI and all-cause mortality. However, D-dimers do not improve the diagnostic performance except if values exceed the 95^th percentile.

A critical role for plasminogen in inflammation

Plasminogen and its active form, plasmin, have diverse functions related to the inflammatory response in mammals. Due to these roles in inflammation, plasminogen has been implicated in the progression of a wide range of diseases with an inflammatory component. In this review, we discuss the functions of plasminogen in inflammatory regulation and how this system plays a role in the pathogenesis of diseases spanning organ systems throughout the body.

The relationship between interleukin-6 levels and physical performance in mobility-limited older adults with chronic low-grade inflammation: The ENRGISE Pilot study

Previous studies have found an inverse relation between serum concentrations of interleukin (IL)-6 and physical performance in seniors, however this was limited to higher functioning older adults with low to moderate levels of inflammation. We explored the consistency of this association in a cohort of mobility limited older adults with chronic low-grade inflammation. This study included 289 participants (≥ 70 years old) with IL-6 level between 2.5 and 30 pg/mL and a walking speed < 1.0 m/sec from the ENRGISE Pilot study. Physical performance was assessed using the short physical performance battery (SPPB), usual gait speed over 400 m, grip strength, and knee extensor and flexor strength measured by isokinetic dynamometry at 60 and 180°/sec. There was a significant inverse correlation between log IL-6 and knee extensor strength at 60°/sec (r= -0.20, p = 0.002), at 180°/sec (r = -0.14, p = 0.037), and knee flexor strength at 60°/sec (r = -0.15, p = 0.021). After adjustment for potential confounders, the values of knee extensor strength at 60°/sec showed a trend toward a progressive reduction across IL-6 tertiles as IL-6 levels increased (p = 0.024). No significant association was found between IL-6 and other objectively measured physical performance. The findings were generally of smaller magnitude and less consistent than previously reported, which suggests that the associations are attenuated in those with both elevated inflammation and mobility limitations. These results have implications for planning and interpreting future intervention studies in older adults with low-grade inflammation and mobility limitations.

Evidence for the important role of inflammation in xenotransplantation

There is increasing evidence of a sustained state of systemic inflammation after pig-to-nonhuman primate (NHP) xenotransplantation (that has been termed systemic inflammation in xenograft recipients [SIXR]). Increases in inflammatory markers, e.g., C-reactive protein, histones, serum amyloid A, D-dimer, cytokines, chemokines, and a decrease in free triiodothyronine, have been demonstrated in the recipient NHPs. The complex interactions between inflammation, coagulation, and the immune response are well-recognized, but the role of inflammation in xenograft recipients is not fully understood. The evidence suggests that inflammation can promote the activation of coagulation and the adaptive immune response, but the exact mechanisms remain uncertain. If prolonged xenograft survival is to be achieved, anti-inflammatory strategies (e.g., the administration of anti-inflammatory agents, and/or the generation of genetically-engineered organ-source pigs that are protected from the effect of inflammation) may be necessary to prevent, control, or negate the effect of the systemic inflammation that develops in xenograft recipients. This may allow for a reduction in the intensity of exogenous immunosuppressive therapy. If immunological tolerance to a xenograft is to be obtained, then control of inflammation may be essential.

Systemic inflammation and resting state connectivity of the default mode network

The default mode network (DMN) encompasses brain systems that exhibit coherent neural activity at rest. DMN brain systems have been implicated in diverse social, cognitive, and affective processes, as well as risk for forms of dementia and psychiatric disorders that associate with systemic inflammation. Areas of the anterior cingulate cortex (ACC) and surrounding medial prefrontal cortex (mPFC) within the DMN have been implicated specifically in regulating autonomic and neuroendocrine processes that relate to systemic inflammation via bidirectional signaling mechanisms. However, it is still unclear whether indicators of inflammation relate directly to coherent resting state activity of the ACC, mPFC, or other areas within the DMN. Accordingly, we tested whether plasma interleukin (IL)-6, an indicator of systemic inflammation, covaried with resting-state functional connectivity of the DMN among 98 adults aged 30-54 (39% male; 81% Caucasian). Independent component analyses were applied to resting state fMRI data to generate DMN connectivity maps. Voxel-wise regression analyses were then used to test for associations between IL-6 and DMN connectivity across individuals, controlling for age, sex, body mass index, and fMRI signal motion. Within the DMN, IL-6 covaried positively with connectivity of the sub-genual ACC and negatively with a region of the dorsal medial PFC at corrected statistical thresholds. These novel findings offer evidence for a unique association between a marker of systemic inflammation (IL-6) and ACC and mPFC functional connectivity within the DMN, a network that may be important for linking aspects of immune function to psychological and behavioral states in health and disease.

Inflammatory markers, D-dimer, pro-thrombotic factors, and physical activity levels in patients with peripheral arterial disease

Men and women with lower extremity peripheral arterial disease (PAD) have reduced physical activity levels compared with persons without PAD. We describe associations between physical activity levels with D-dimer, pro-coagulant factors, and inflammatory markers in patients with PAD. Participants were188 patients with PAD identified from non-invasive vascular laboratories. Physical activity was measured over 7 days with a vertical accelerometer. We measured the ankle brachial index (ABI) and levels of D-dimer, C-reactive protein (CRP), fibrinogen, serum amyloid A (SAA), prothrombin 1.2, t-PA antigen, PAI-1, and the t-PA antigen=PAI-1 ratio. Adjusting for age, sex, race, body mass index, ABI, comorbidities, smoking, total cholesterol=HDL ratio and statin use (for CRP only), we found significant inverse linear associations between physical activity levels and log D-dimer (p 1/4 0.002), log CRP (p < 0.001), fibrinogen (p 1/4 0.014), and log SAA (p 1/4 0.012). There were no significant associations between physical activity levels and other blood factors. In an analysis adjusting for all blood factors simultaneously along with known and potential confounders, log D-dimer was the only blood factor associated significantly with physical activity levels (p 1/4 0.036). Based on these findings, future studies should assess whether interventions to increase physical activity in patients with PAD reduce levels of D-dimer and inflammatory markers.

Ethnically-Based Theme House Residency and Expected Discrimination Predict Downstream Markers of Inflammation Among College Students

We examined participation in an ethnically based residential program or “theme house” during the first year of college as a predictor of downstream immune system inflammation among undergraduates. Using a 4-year prospective design, we compared markers of inflammation among Latino/Latina students in a residential theme program with a matched sample of nonresidents. Students provided oral mucosal transudate samples for the assessment of circulating Interleukin 6 (IL-6), an inflammatory cytokine linked to health vulnerabilities. Findings suggest a protective benefit of theme house residency especially among students with anxious expectations of discrimination. Such expectations predicted higher levels of IL-6 after the first year of college among nonresidents only. In years 2–3, following exit from the theme house, the relationship between expected discrimination and IL-6 levels remained positive among nonresidents and was attenuated among residents, controlling for past IL-6 levels. Culturally based spaces may therefore offset the physiological burden of expected discrimination among undergraduates.

Task-switching ability protects against the adverse effects of pain on health: A longitudinal study of older adults

OBJECTIVE

Ageing is often accompanied by increases in pain, which may threaten physical health. Successfully managing increased pain requires the ability to switch attention away from the pain and towards adaptive health cognitions and behaviours. However, no study to date has tested how pain interacts with task-switching ability to predict future health in older adults. Additionally, no study has tested whether objective (i.e., task-switching performance) or subjective measures of cognitive ability have a stronger impact on future health.

DESIGN/METHODS

The current study tested these interactions in community-dwelling older adults. Participants included 150 older adults who provided pain, task-switching ability, subjective cognitive functioning, and health data every 6 months for up to 5 years.

RESULTS

Multilevel modelling was used to analyse the data, yielding gammas (γ) analogous to unstandardized beta weights in regression. A significant interaction between task-switching and pain indicated that when task-switching ability was lower than usual, higher-than-usual pain predicted poorer health at the following wave (γ = 0.30, SE = 0.12, t(663) = 2.45, p = .009; 95% CI: 0.07-0.65). When task-switching ability was higher than usual, there was no effect of pain on health (γ = -0.13, t(663) = -0.85, p = .39; 95% CI: -0.44-0.17). No significant interaction was found for subjective cognitive functioning.

CONCLUSIONS

Objective task-switching ability, but not subjective cognitive functioning, may have health-protective effects when older adults experience increases in pain.

STATEMENT OF CONTRIBUTION

What is already known on the subject? As people age, they are more likely to experience pain. Increases in pain threaten health. Older adults are at particular risk for both increased pain and poor health. What does this study add? When pain levels are higher than usual, task-switching ability protects older adults from future declines in health. Within people, task-switching ability interacts with pain to promote healthy ageing.

Fibrinogen Degradation Products and Periodontitis: Deciphering the Connection

INTRODUCTION

Fibrinogen degradation products (e.g. D-dimer) arise from digested fibrin clots and fibrinogen. Elevated concentrations accompany activation of coagulation and fibrinolysis and indicate chronic inflammatory diseases. D-Dimer tests are a quick, noninvasive method to rule out abnormal clotting. Periodontitis strongly affects the haemostatic system and evokes a procoagulant state. Correlation of chronic periodontitis with early indicators of disease (biomarkers) might be useful.

AIM

The aim of the study was to examine whether the plasma D-dimer concentration reflects the progression of chronic periodontitis and the beneficial effect of periodontal therapy.

MATERIALS AND METHODS

Forty randomly selected subjects were divided into four groups, Group I: 10 healthy subjects, Group II: 10 with mild periodontitis, Group III: 10 with moderate periodontitis, Group IV: 10 with severe periodontitis. After thorough dental and periodontal examination, 3 mL of venous blood was collected for measurement of fibrinogen degradation products.

RESULTS

The patients with moderate and chronic periodontitis exhibited high concentrations of D-dimer (mean value 434.98-535.52 mcg/mL), whereas subjects with mild or no periodontitis exhibited values of 329.78-211.29 mcg/mL. Concentrations of D-dimer were significantly reduced after therapy of all classes of periodontitis.

CONCLUSION

Periodontal treatment can reduce amount of D-dimer in the plasma. A higher than normal concentration is observed in chronic periodontitis.

Brain morphology links systemic inflammation to cognitive function in midlife adults

BACKGROUND

Inflammation is linked to cognitive decline in midlife, but the neural basis for this link is unclear. One possibility is that inflammation associates with adverse changes in brain morphology, which accelerates cognitive aging and later dementia risk. Clear evidence is lacking, however, regarding whether inflammation relates to cognition in midlife via changes in brain morphology. Accordingly, the current study examines whether associations of inflammation with cognitive function are mediated by variation in cortical gray matter volume among midlife adults.

METHODS

Plasma levels of interleukin (IL)-6 and C-reactive protein (CRP), relatively stable markers of peripheral systemic inflammation, were assessed in 408 community volunteers aged 30-54 years. All participants underwent structural neuroimaging to assess global and regional brain morphology and completed neuropsychological tests sensitive to early changes in cognitive function. Measurements of brain morphology (regional tissue volumes and cortical thickness and surface area) were derived using Freesurfer.

RESULTS

Higher peripheral inflammation was associated with poorer spatial reasoning, short term memory, verbal proficiency, learning and memory, and executive function, as well as lower cortical gray and white matter volumes, hippocampal volume and cortical surface area. Mediation models with age, sex and intracranial volume as covariates showed cortical gray matter volume to partially mediate the association of inflammation with cognitive performance. Exploratory analyses of body mass suggested that adiposity may be a source of the inflammation linking brain morphology to cognition.

CONCLUSIONS

Inflammation and adiposity might relate to cognitive decline via influences on brain morphology.

A Novel Analytic Technique to Measure Associations Between Circulating Biomarkers and Physical Performance Across the Adult Life Span

Understanding associations between circulating biomarkers and physical performance across the adult life span could aid in better describing mechanistic pathways leading to disability. We hypothesized that high concentrations of circulating biomarkers would be associated with lower functioning across study populations representing the adult life span. The data were from four intervention and two observational studies with ages ranging 22-89 years. Biomarkers assayed included inflammatory, coagulation, and endothelial function markers. Physical performance was measured either by VO2peak (studies of young and middle-aged adults) or usual gait speed (studies of older adults). Partialled (by age, body mass index, race, and sex) and weighted common correlations were calculated between biomarkers and physical performance. Homogeneity of the associations was also assessed. Interleukin-6 (weighted r = -.22), tumor necrosis factor receptor 2 (weighted r = -.19), D-dimer (weighted r = -.16), tumor necrosis factor receptor 1 (weighted r = -.15), granulocyte colony-stimulating factor (weighted r = -.14), and tumor necrosis factor alpha (weighted r = -.10) were all significantly inversely correlated with physical performance (p < .05). All significant correlations were homogeneous across studies. In summary, we observed consistent inverse associations between six circulating biomarkers and objective measures of physical performance. These results suggest that these serum biomarkers may be broadly applicable for detection, trajectory, and treatment monitoring of physical function across the life span or possibly for midlife predictors of functionally deleterious conditions.

Associations between fibrin D-dimer, markers of inflammation, incident self-reported mobility limitation, and all-cause mortality in older men

OBJECTIVES

To examine the independent relationships between fibrin D-dimer, interleukin 6 (IL-6), C-reactive protein (CRP), and fibrinogen and incident mobility limitation and mortality.

DESIGN

Prospective.

SETTING

General practice in 24 British towns.

PARTICIPANTS

Men aged 60 to 79 without prevalent heart failure followed up for an average of 11.5 years (N = 3,925).

MEASUREMENTS

All-cause mortality (n = 1,286) and self-reported mobility disability obtained at examination in 1998 to 2000 and in a postal questionnaire 3 to 5 years later in 2003.

RESULTS

High D-dimer (top vs lowest tertile: adjusted odds ratio (aOR) = 1.46, 95% confidence interval = 1.02-2.05) and IL-6 (aOR = 1.43, 95% CI = 1.01-2.02) levels (but not CRP or fibrinogen) were associated with greater incident mobility limitation after adjustment for confounders and prevalent disease status. IL-6, CRP, fibrinogen, and D-dimer were significantly associated with total mortality after adjustment for confounders. Only D-dimer and IL-6 predicted total mortality independent of each other and the other biomarkers. The adjusted hazard ratio (aHR) was 1.16 (95% CI = 1.10-1.22) for a standard deviation increase in log D-dimer and 1.10 (95% CI = 1.04-1.18) for a standard deviation increase in log IL-6. D-dimer was independently related to vascular and nonvascular mortality, and IL-6 was independently related to vascular mortality. Risks of mobility limitation and mortality were greatest in those with a combination of high D-dimer and IL-6 levels.

CONCLUSION

D-dimer and IL-6 are associated with risk of mobility limitation and mortality in older men without heart failure. The findings suggest that coagulation leads to functional decline and mortality s that inflammation does not explain.

Interleukin-6 predicts short-term global functional decline in the oldest old: results from the BELFRAIL study

The chronic inflammatory state at old age may contribute to the pathophysiology of or reflect chronic conditions resulting in loss of physical and mental functioning. Therefore, our objective was to examine the predictive value of a large battery of serum inflammatory markers as risk indicators for global functional decline and its specific physical and mental determinants in the oldest old. Global functional decline and specific aspects of physical and mental functional decline were assessed during an average of 1.66 years (±0.21) in a sample of 303 persons aged 80 years or older of the BELFRAIL study. Serum levels of 14 inflammatory proteins, including cytokines, growth factors, and acute phase proteins, were measured at baseline. Almost 20 % of the participants had a significant global functional decline over time. Interleukin (IL)-6 serum levels were uniquely positively associated with global functional decline, even after correcting for multiple confounders (odds ratio 1.51). Odds ratios for the individual aspects (physical dependency, physical performance, cognition, and depression) of functioning were lower, and composite scores of physical or mental decline were not significant. The proportion of global functional decline exhibited a dose-response curve with increasing levels of IL-6. Thus, IL-6 is an independent risk indicator for accelerated global functional decline in the oldest old. Our results suggest that simple serum levels of IL-6 may be very useful in short-term identification or evaluation of global functional status in the oldest old.

Inflammatory cytokine levels and breast cancer risk factors: racial differences of healthy Caucasian and African American women

PURPOSE/OBJECTIVES

To examine racial differences in inflammatory cytokine levels (interleukin [IL]-6 and interferon-gamma [IFN-γ]) and breast cancer (BC) risk factors between healthy Caucasian and African American women; to examine differences in relationships of inflammatory cytokine levels with BC risk factors between these groups of women; and to determine the independent contribution of race to IL-6 and IFN-γ after controlling for relevant covariates.

DESIGN

Cross-sectional and correlational descriptive design.

SETTING

Community surrounding a state university health system in the southeastern United States.

SAMPLE

113 healthy women (65 Caucasians and 48 African Americans) aged 20 years or older and not pregnant.

METHODS

Secondary analysis of data collected from self-report questionnaires and blood samples.

MAIN RESEARCH VARIABLES

Inflammatory cytokine levels, BC risk factors (age, age at menarche, age at first live birth, family history of BC, breast biopsy, breastfeeding history and duration, body mass index, and physical activity), and race.

FINDINGS

Significant racial differences were noted in IL-6 and IFN-γ levels, reproductive or hormonal and lifestyle BC risk factors, and relationships between African American and Caucasian women. Controlling for all other effects, race appeared to be a significant predictor for IL-6 and IFN-γ.

CONCLUSIONS

Racial differences in inflammatory cytokines and BC risk factors may provide partial evidence for existing racial disparities in BC for African American and Caucasian women. Additional studies are needed to confirm that potential.

IMPLICATIONS FOR NURSING

Additional biobehavioral research in racial disparities in BC may help to inform nurses to target race-specific modifications of lifestyle and behavioral factors to reduce BC health disparity between African American and Caucasian women.

KNOWLEDGE TRANSLATION

Being an African American woman predicted a higher level of inflammatory cytokine production after controlling for selected BC risk factors. Great potential exists for inflammatory responses as one of the underlying biologic mechanisms for existing BC disparity and for culturally tailored lifestyle or behavioral modification interventions for reducing BC risk and racial disparity.

Intraindividual variability over time in plasma biomarkers of inflammation and effects of long-term storage

PURPOSE

Systemic measures of chronic inflammation, often based on a single blood draw, are frequently used to study the associations between inflammation and chronic diseases such as cancer. However, more information is needed on the measurement error in these markers due to laboratory error, within-person variation over time, and long-term storage.

METHODS

We investigated the intraindividual variability of inflammation markers C-reactive protein (CRP), interleukin-6 (IL-6), and soluble tumor necrosis factor receptors I and II (sTNFRI and II) in a subsample of the Seattle Barrett's esophagus study cohort. Two fasting blood samples were collected between 1995 and 2009 from 360 participants on average 1.8 years apart. CRP, IL-6, and sTNF receptor levels were measured by immunonephelometry, ELISA, and multiplex assays, respectively. Intra- and inter-batch coefficients of variation (CV) were estimated using blinded pooled samples within each batch. Intraclass correlations (ICCs) were computed using random effects ANOVA.

RESULTS

Intra- and inter-batch CVs for the pooled plasma aliquots were low (2.4-8.9 %), suggesting little laboratory variability. Reliability over time was excellent for sTNF receptors (ICCsTNF-RI = 0.89, ICCsTNF-RII = 0.85) and fair-to-good for CRP and IL-6 (ICCCRP = 0.55, ICCIL-6 = 0.57). For samples stored for over 13 years, the ICCs for CRP and IL-6 were decreased but those for sTNF receptors were unaffected.

CONCLUSION

sTNF receptor levels are more stable within person over time than CRP or IL-6. Long-term storage of samples appears to increase the variability of CRP and IL-6 measures, while the reliability of soluble TNF receptor measures was not affected by storage time.

Correlates of elevated interleukin-6 and C-reactive protein in persons with or at high risk for HCV and HIV infections

BACKGROUND

HIV and hepatitis C virus (HCV) infections may increase interleukin-6 (IL-6) and C-reactive protein (CRP). However, relationships between inflammatory biomarkers, chronic viral infections, clinical factors, and behavioral factors remain poorly understood.

METHODS

Using linear regression, we modeled cross-sectional associations between loge IL-6 or loge CRP levels and HCV, HIV, injection drug use, and comorbidity among 1191 injection drug users.

RESULTS

Mean age was 47 years, 46.0% reported currently injecting drugs, 59.0% were HCV monoinfected, and 27% were HCV/HIV coinfected. In multivariable models, higher loge IL-6 was associated with HCV monoinfection [β = 0.191, 95% confidence interval (CI): 0.043 to 0.339] and HCV/HIV coinfection (β = 0.394, 95% CI: 0.214 to 0.574). In contrast, HCV monoinfection (β = -0.523, 95% CI: -0.275 to -0.789) and HCV/HIV coinfection (β = -0.554 95% CI: -0.260 to -0.847) were associated with lower CRP. Lower CRP with HCV infection was independent of liver fibrosis severity, synthetic function, or liver injury markers; CRP decreased with higher HCV RNA. Increased injection intensity was associated with higher IL-6 (P = 0.003) and CRP (P < 0.001); increasing comorbidity (P < 0.001) and older age (P = 0.028) were associated with higher IL-6; older age was associated with higher CRP among HCV-uninfected participants (P = 0.021).

CONCLUSION

HIV and HCV infections contribute to chronic inflammation; however, reduced CRP possibly occurs through HCV-mediated mechanisms. Findings highlight potentially modifiable contributors to inflammation.

Negative emotions predict elevated interleukin-6 in the United States but not in Japan

Previous studies conducted in Western cultures have shown that negative emotions predict higher levels of pro-inflammatory biomarkers, specifically interleukin-6 (IL-6). This link between negative emotions and IL-6 may be specific to Western cultures where negative emotions are perceived to be problematic and thus may not extend to Eastern cultures where negative emotions are seen as acceptable and normal. Using samples of 1044 American and 382 Japanese middle-aged and older adults, we investigated whether the relationship between negative emotions and IL-6 varies by cultural context. Negative emotions predicted higher IL-6 among American adults, whereas no association was evident among Japanese adults. Furthermore, the interaction between culture and negative emotions remained even after controlling for demographic variables, psychological factors (positive emotions, neuroticism, extraversion), health behaviors (smoking status, alcohol consumption), and health status (chronic conditions, BMI). These findings highlight the role of cultural context in shaping how negative emotions affect inflammatory physiology and underscore the importance of cultural ideas and practices relevant to negative emotions for understanding of the interplay between psychology, physiology, and health.

Adversity and inflammation among adolescents: a possible pathway to long-term health risk

It has been suggested that childhood adversity programs an inflammatory phenotype characterized by higher levels of systemic inflammation and increased health risk in later life. If this is the case, one might expect associations of early childhood adversity with elevated levels of circulating inflammatory molecules in adolescence. To date, evidence for this association is mixed. This issue of Psychosomatic Medicine includes two studies by Pietras and Goodman and Low et al. that extend the existing literature and provide initial evidence that coping styles and perceived social standing may buffer against the impact of adversity on inflammation among adolescents. The current commentary considers these interesting findings in the context of the existing literature and discusses a critical need for longitudinal studies examining whether individual risk and resilience factors moderate the long-term health effects of childhood adversity, possibly via early programming of inflammatory pathways.

Interleukin 6 plasma concentration associates with cognitive decline: the northern Manhattan study

BACKGROUND

Interleukin 6 (IL-6) is an inflammatory cytokine that has been associated with vascular disease and cognitive impairment, but few studies have examined these relationships in population-based studies that include Hispanic and Black people who often have a greater prevalence of vascular risk factors and are at an elevated risk of dementia than Whites. We examined relative elevations of plasma IL-6 concentrations in relation to cognitive decline in a stroke-free racially/ethnically diverse community-based sample from Northern Manhattan.

METHODS

We used mixed effects models to measure the effect of IL-6 on change in performance on the modified Telephone Interview for Cognitive Status (TICS-m) measured annually in our cohort, adjusting for sociodemographic and vascular risk factors.

RESULTS

There were 1,224 participants with IL-6 levels (median 1.5 pg/ml, interquartile range 0.83-2.57 pg/ml) and TICS-m data available (mean = 31.6 points, SD 6.5). The mean age was 71 (SD 9.3; 64% women, 59% Hispanic, 19% Black, 19% White) with 3,406 person-years and a median 3.0 years of follow-up (interquartile range 1.1-4.0 years). Participants with IL-6 levels above the median showed greater cognitive decline on the TICS-m compared to those with levels below the median, adjusting for sociodemographic and vascular factors (β = -0.17 points/year, p = 0.02). Decline on the TICS-m among participants with IL-6 above the median differed by age (p for interaction <0.001). There was no interaction by race/ethnicity, vascular risk factors, C-reactive protein, apolipoprotein ε4 allele status, or the metabolic syndrome among nondiabetics.

CONCLUSIONS

IL-6 associated with cognitive decline among older participants in this racially/ethnically diverse sample independent of other vascular risk factors and C-reactive protein.

Adherence to mediterranean diet and decline in walking speed over 8 years in community-dwelling older adults

OBJECTIVES

To determine the association between Mediterranean diet (MedDiet) score and 20-m walking speed over 8 years.

DESIGN

Health, Aging and Body Composition Study (Health ABC) beginning in 1997/98.

SETTING

Community.

PARTICIPANTS

Two thousand two hundred twenty-five well-functioning individuals aged 70 and older.

MEASUREMENTS

Walking speed was assessed in relation to low, medium, and high adherence to the MedDiet (0-2, 3-5, 6-9 points, respectively).

RESULTS

Individuals in the highest MedDiet adherence group were more likely to be male; less likely to smoke; and more likely to have lower body mass index, higher energy intake, and greater physical activity (P < .05). Usual and rapid 20-m walking speed were highest in the high MedDiet adherence group than in the other groups (high, 1.19 ± 0.19 m/s; medium, 1.16 ± 0.21 m/s; low, 1.15 ± 0.19 m/s, P = .02, for usual speed; high, 1.65 ±0.30 m/s; medium, 1.59 ± 0.32 m/s; low, 1.55 ± 0.30 m/s, P = .001, for rapid speed). Over 8 years, usual and rapid 20-m walking speed declined in all MedDiet adherence groups. Higher MedDiet adherence was an independent predictor of less decline in usual 20-m walking speed (P = .049) in generalized estimating equations adjusted for age, race, sex, site, education, smoking, physical activity, energy intake, health status, depression and cognitive score. The effect decreased after adding total body fat percentage to the model (P = .13). Similar results were observed for MedDiet adherence and rapid 20-m walking speed; the association remained significant after adjustment for total body fat percentage (P = .01). The interaction between time and MedDiet adherence was not significant in any of the models.

CONCLUSION

Walking speed over 8 years was faster in those with higher MedDiet adherence at baseline. The differences remained significant over 8 years, suggesting a long-term effect of diet on mobility performance with aging.

Current understanding of the bi-directional relationship of major depression with inflammation

Consistent evidence links major depression and its affective components to negative health outcomes. Although the pathways of these effects are likely complex and multifactorial, recent evidence suggests that innate inflammatory processes may play a role. An overview of current literature suggests that pathways between negative moods and inflammation are bi-directional. Indeed, negative moods activate peripheral physiologic mechanisms that result in an up regulation of systemic levels of inflammation. Conversely, peripheral inflammatory mediators signal the brain to affect behavioral, affective and cognitive changes that are consistent with symptoms of major depressive disorder. It is likely that these pathways are part of a complex feedback loop that involves the nervous, endocrine, and immune systems and plays a role in the modulation of peripheral inflammatory responses to central and peripheral stimuli, in central responses to peripheral immune activation and in the maintenance of homeostatic balance. Further research is warranted to fully understand the role of central processes in this feedback loop, which likely contributes to the pathophysiology of mental and physical health.

Relations of a marker of endothelial activation (s-VCAM) to function and mortality in community-dwelling older adults

BACKGROUND

We wished to determine if a marker of endothelial dysfunction/activation soluble vascular cell adhesion molecule (s-VCAM)-was related to functional status and mortality in community-dwelling older adults independent of the known effects of markers of inflammation and coagulation.

METHODS

Data came from the third and fourth in-person waves of the Duke Established Populations for Epidemiologic Studies of the Elderly. Participants (aged ≥ 71 years) had participated in a blood draw (N = 1,551) from which concentrations of s-VCAM, interleukin-6, and D-dimer were determined. Information was gathered in-person on demographics, health behaviors, chronic health conditions, and functional status (Katz, Rosow-Breslau, Nagi). Death was determined through the National Death Index. Multivariable regression analysis was used to examine the adjusted association of s-VCAM with functional status; Cox proportional hazards models ascertained hazard of mortality.

RESULTS

Controlled analyses indicated that cross-sectionally, but not longitudinally (4 years later), greater s-VCAM concentrations were associated with poorer function as measured by the Katz and Rosow-Breslau scales (p < .05 for both), independent of interleukin-6 and D-dimer. In controlled analyses, s-VCAM (p = .002), D-dimer (p = .008), and interleukin-6 (p = .01) were independently related to 4-year mortality; 1 SD increase in log concentration conferred 1.2-, 1.1-, and 1.2-fold increases in mortality, respectively. The greatest hazard of mortality was observed within the first year after measurement. s-VCAM concentrations were not predictive of 15-year mortality.

CONCLUSIONS

Independent of inflammation and coagulation markers, endothelial dysfunction serves as a marker of, and potentially contributes causally to, poor function and death in community-dwelling older adults.

Inflammatory markers and gait speed decline in older adults

BACKGROUND

Increased inflammatory activity and gait speed decline are common with aging, but the association between the two is not well established. The objective of this study was to determine the influence of inflammatory markers, interleukin-6 (IL-6), and tumor necrosis factor alpha, on gait speed performance and decline in older adults.

METHODS

We conducted cross-sectional and longitudinal analyses of 333 adults aged 70 and older (61% women) with gait and biomarker assessments identified from participants in the Einstein Aging Study, a community-based aging study. Gait velocity measured at baseline and annual follow-up visits (median follow-up 2.3 years) was the main outcome.

RESULTS

At baseline, higher interleukin-6 levels were associated with slower gait velocity (estimate -4.90 cm/s, p = .008). Adjusted for age, gender, education, and medical illnesses, a one-unit increase in baseline log IL-6 levels was associated with a 0.98 cm/s faster gait speed decline per year (p = .002). The results remained significant after adjustments for additional potential confounders such as physical activity levels, body mass index, and medications. Participants in the highest IL-6 quartile had a 1.75 cm/s/year faster decline in gait velocity compared with those in the lowest quartile (p = .002). Tumor necrosis factor alpha was not associated with gait velocity at cross-section or with gait speed decline.

CONCLUSIONS

IL-6 levels are associated with gait performance in community residing seniors and predicts risk of gait speed decline in aging.

Immune function and HPA axis activity in free-ranging rhesus macaques

In mammals, the hypothalamic-pituitary-adrenal (HPA) axis and immune system play an important role in the maintenance of homeostasis. Dysregulation of either system resulting, for example, from psychosocial or reproductive stress increases susceptibility to disease and mortality risk, especially in aging individuals. In a study of free-ranging rhesus macaques, we examined how female age, reproductive state, social rank, and body condition influence (i) aspects of cytokine biology (plasma concentrations of interleukin-1 receptor antagonist (IL-1ra), IL-6 and IL-8), and (ii) HPA axis activity (plasma and fecal glucocorticoid levels). We also assessed individual differences in cytokine and hormone concentrations over time to determine their consistency and to investigate relations between these two indicators of physiological regulation and demand. Female monkeys showed marked increases in HPA axis activity during pregnancy and lactation, and increased circulating levels of IL-1ra with advancing age. Inter-individual differences in IL-1ra and IL-8 were consistent over successive years, suggesting that both are stable, trait-like characteristics. Furthermore, the concentrations of fecal glucocorticoid hormones in non-pregnant, non-lactating females were correlated with their plasma cortisol and IL-8 concentrations. Some individuals showed permanently elevated cytokine levels or HPA axis activity, or a combination of the two, suggesting chronic stress or disease. Our results enhance our understanding of within- and between-individual variation in cytokine levels and their relationship with glucocorticoid hormones in free-ranging primates. These findings can provide the basis for future research on stress and allostatic load in primates.

The role of serum D-dimer level in the diagnosis of patients admitted to the emergency department complaining of chest pain

This study investigated D-dimer levels in 241 patients admitted to the emergency department with sudden-onset chest pain. The patient group included those diagnosed with acute coronary syndrome (ACS; i.e., unstable angina pectoris [USAP], non-ST elevated myocardial infarction [NSTEMI], ST-elevated myocardial infarction [STEMI]); the control group included those diagnosed with non-cardiac chest pain. Mean serum levels of D-dimer, creatine kinase-MB (CK-MB) and troponin I (TPI) were compared between the groups. Levels of D-dimer, CK-MB and TPI in the patient group were significantly higher than in the control group. There were also significantly higher D-dimer, CK-MB and TPI levels in the STEMI and NSTEMI patient subgroups compared with the control group. Only the D-dimer level was significantly higher in the USAP subgroup versus the control group. The sensitivity and specificity of D-dimer for ACS were 83.7% and 95.4%, respectively, suggesting that evaluating D-dimer levels might be useful in the emergency room for diagnosing ACS and predicting mortality in patients presenting with acute chest pain.

Population differences in proinflammatory biology: Japanese have healthier profiles than Americans

The pleiotropic cytokine, interleukin-6 (IL-6), has emerged as a key factor in the biology of aging and the physiology of inflammation. Yet much of what we know about the normal functioning of IL-6 has been generated primarily from research on European populations and Americans of European descent. Our analyses compared IL-6 levels in 382 middle-aged and older Japanese to the values found in 1209 Caucasian- and African-Americans from the Midlife in the United States survey (MIDUS). Across the life span from 30 to 80 years of age, mean IL-6 levels were strikingly lower in Japanese individuals. Significantly lower levels of C-reactive protein (CRP) and fibrinogen (FBG) provided confirmatory evidence for a population difference in proinflammatory activity. Because IL-6 release has been associated with obesity, differences in body mass index (BMI) were taken into consideration. Japanese had the lowest, and African-Americans had the highest overall BMIs, but significant group differences in IL-6 persisted even after BMI was included as a covariate in the analyses. Additional support for distinct variation in IL-6 biology was generated when systemic levels of the soluble receptor for IL-6 (sIL-6r) were evaluated. Serum sIL-6r was higher in Japanese than Americans, but was most notably low in African-Americans. Our cytokine data concur with national differences in the prevalence of age-related illnesses linked to inflammatory physiology, including cardiovascular disease. The findings also highlight the importance of broadening the diversity of people included in population studies of health and aging, especially given the relative paucity of information for some Asian countries and on individuals of Asian heritage living in the US.

Cytokines and memory across the mature life span of women

Increasing evidence suggests a role of the immune system in modulation of cognition, but details on affected memory systems are largely lacking. We therefore aimed to study the relation between selected cytokines and subsets of memory, and the impact of age in these relations. From a random population-based sample (the Betula Prospective Cohort Study), 298 women (age 45-90) were studied in terms of episodic recall and recognition, semantic fluency and knowledge, and prospective memory. Circulating cytokines of relevance for cognition and aging were measured with ELISA. Levels of interleukin (IL)-6 and sIL-2R were significantly and negatively associated with most cognitive variables, while the opposite was true for IL-1β. Age shared substantial variance with both cytokines and memory, and turned most correlations non-significant when controlled for together with education, BMI and presence of disease. Interactions between age and cytokines were further analyzed in multiple regressions. For IL-6, significant negative interactions with age were found for semantic fluency (p<0.05) and prospective memory (p<0.01), and for sIL-2R in predicting semantic knowledge (p<0.05), indicating an increased negative impact of these cytokines on memory with increasing age. In conclusion, the study indicates a relation between cytokines and memory that appears to be largely mediated by age, and supports the suggestion that cytokine dysregulation with higher age may interact with cognitive aging.

Systemic inflammation and the metabolic syndrome among middle-aged community volunteers

The metabolic syndrome is conceptualized as a clustering of risk factors--including insulin resistance, dyslipidemia, central adiposity, and elevated blood pressure (BP)--that increase the risk for cardiovascular disease and type 2 diabetes mellitus. Recent evidence suggests that markers of systemic inflammation may be included in the definition of the syndrome and play some role in its pathogenesis. In this study, we use a statistical modeling technique, confirmatory factor analysis, to evaluate relationships of systemic inflammation, as measured by plasma concentrations of C-reactive protein and interleukin-6, with the component factors of the metabolic syndrome (insulin resistance, dyslipidemia, central adiposity, and elevated BP) and to examine whether inflammation is a potential common pathway linking established components to the full syndrome. Subjects were 645 community volunteers aged 30 to 54 years (48% male, 82% European American, 18% African American). Consistent with existing literature, structural equation modeling adjusting for age, sex, and race confirmed a higher-order common factor underlying the covariation of insulin resistance, dyslipidemia, adiposity, and BP. Inflammation was positively associated with this common factor, accounting for 54% of its variance and partially mediating statistical aggregation of the component factors comprising the metabolic syndrome. These results were particularly strong for adiposity, raising the possibility that inflammatory processes stimulated by intraabdominal adipose tissue contribute to the development of the metabolic syndrome. The inclusion of inflammatory markers in the clinical definition of metabolic syndrome seems warranted and may improve prognostic assessment of risk of type 2 diabetes mellitus and cardiovascular disease.

Age-related changes in neural volume and microstructure associated with interleukin-6 are ameliorated by a calorie-restricted diet in old rhesus monkeys

Systemic levels of proinflammatory cytokines such as interleukin-6 (IL-6) increase in old age and may contribute to neural atrophy in humans. We investigated IL-6 associations with age in T1-weighted segments and microstructural diffusion indices using MRI in aged rhesus monkeys (Macaca mulatta). Further, we determined if long-term 30% calorie restriction (CR) reduced IL-6 and attenuated its association with lower tissue volume and density. Voxel-based morphometry (VBM) and diffusion-weighted voxelwise analyses were conducted. IL-6 was associated with less global gray and white matter (GM and WM), as well as smaller parietal and temporal GM volumes. Lower fractional anisotropy (FA) was associated with higher IL-6 levels along the corpus callosum and various cortical and subcortical tracts. Higher IL-6 concentrations across subjects were also associated with increased mean diffusivity (MD) throughout many brain regions, particularly in corpus callosum, cingulum, and parietal, frontal, and prefrontal areas. CR monkeys had significantly lower IL-6 and less associated atrophy. An IL-6xCR interaction across modalities also indicated that CR mitigated IL-6 related changes in several brain regions compared to controls. Peripheral IL-6 levels were correlated with atrophy in regions sensitive to aging, and this relationship was decreased by CR.

When is enough measurement, enough? Generalizability of primate immunity over time

A statistical generalizability analysis gauges the degree to which a single assessment of a parameter successfully estimates that measure over repeated assessments for that individual. The generalizability of enumerative and functional immune parameters was estimated for two species of macaque monkeys assessed every 3 months between 18 and 42 months of age. Subjects were cross-balanced by species (bonnet, Macaca radiata, n=22; pigtail, Macaca nemestrina, n=21), sex (male, n=21; female, n=22), and brief early maternal separation with reunion (control, n=21; separated, n=22). Cell subset analysis showed the best generalizability (35-69%). Natural cytotoxicity also performed well (44-70%), but when computed on a lysis per cell basis, removing the effect of cell phenotype, it was less stable (15-48%). For most immune parameters, at least 5 assessments would be necessary to establish conventionally reliable (0.80) characterizations of long-term, stable individual differences in immunity, and three for minimally reliable (0.60) characterizations. More reactive parameters, as well as more behaviorally reactive species, yielded more generalizable results. Cell subsets that are typically most sensitive to acute stress (CD8, CD16) were more stable than other subsets (CD4, CD20). Behaviorally reactive species (pigtail) yielded more stable natural cytotoxicity results than the less reactive species (bonnet). Sex and rearing condition (early, brief maternal separation) did not substantially affect generalizability, although females tended to generate more stable results than did males.

Parental education is related to C-reactive protein among female middle-aged community volunteers

Growing evidence suggests that socioeconomic attributes of both childhood and adulthood confer risk for cardiovascular morbidity and mortality. In this study, we examine the association of both parental and individual educational attainment with C-reactive protein (CRP), an inflammatory mediator relevant to cardiovascular pathophysiology, in a mid-life community sample. Subjects were 811 men and women (394 men/417 women; 87% European-American/13% African-American), 30-54 years of age. Plasma concentrations of CRP were determined from blood samples obtained at a single session following an overnight fast. Regression analyses adjusting for age and race showed both parental education and individual education to be associated inversely with CRP in women, but not men. The relationship of parental education with CRP in women persisted on multivariable adjustment for both lifestyle risk factors (smoking, alcohol consumption, sleep, exercise, body mass index) and individual SES. Independent of reported personal educational attainment, mid-life adult women whose parents achieved fewer years of educational attainment exhibit higher levels of circulating CRP than women with higher parental education. This association may help explain the increased risk of atherosclerotic cardiovascular morbidity and mortality conferred by low childhood socioeconomic status.

Association between inflammatory components and physical function in the health, aging, and body composition study: a principal component analysis approach

BACKGROUND

In older adults, studies demonstrate an inverse relationship between physical function and individual inflammatory biomarkers. Given that the inflammatory response is a complex system, a combination of biomarkers may increase the strength and consistency of these associations. This study uses principal component analysis to identify inflammatory "component(s)" and evaluates associations between the identified component(s) and measures of physical function.

METHODS

Principal component analysis with a varimax rotation was used to identify two components from eight inflammatory biomarkers measured in 1,269 older persons. The study sample is a subset of the Health, Aging, and Body Composition study.

RESULTS

The two components explained 56% of the total variance in the data (34%, component 1 and 22%, component 2). Five markers (tumor necrosis factor-alpha [TNF-alpha], sTNFRI, sTNFRII, interleukin [IL]-6sR, IL-2sR) loaded highest on the first component (TNF-alpha related), whereas three markers (C-reactive protein [CRP], IL-6, plasminogen activator inhibitor-1) loaded highest on the second component (CRP related). After adjusting for age, sex, race, site, sampling indicator, total lean and fat mass, physical activity, smoking, and anti-inflammatory drug use, knee strength and a physical performance battery score were inversely related to the TNF-alpha-related component, but not to the CRP-related component (knee strength: betaTNFalpha = -2.71, p = .002; betaCRP = -0.88, p = .325; physical performance battery score: betaTNFalpha = -0.05, p < .001; betaCRP = -0.02, p = .171). Both components were positively associated with 400-m walk time, inversely associated with grip strength, and not associated with 20-m walking speed.

CONCLUSIONS

At least two inflammatory components can be identified in an older population, and these components have inconsistent associations with different aspects of physical performance.

Socioeconomic position and inflammatory and immune biomarkers of cardiovascular disease: applications to the Panel Study of Income Dynamics

Biomarkers are an important aspect of research linking psychosocial stress and health. This article aims to characterize the biological pathways that may mediate the relationship between socioeconomic position (SEP) and cardiovascular disease (CVD) and address opportunities for further research within the Panel Study of Income Dynamics (PSID), with a focus on psychosocial stressors related to SEP. We review the literature on CVD biomarkers, including adhesion and proinflammatory molecules (interleukin-6, other cytokines, C-reactive proteins, fibrinogen, etc.) and microbial pathogens. The impact of socioeconomic determinants and related psychosocial stressors on CVD biomarkers mediated by behavioral and central nervous system pathways are described. We also address measurement and feasibility issues, including specimen collection methods, processing and storage procedures, laboratory error, and within-person variability. In conclusion, we suggest that PSID consider adding important assessments of specific CVD biomarkers and mediating behavioral measures, health, and medications that will ultimately address many of the gaps in the literature regarding the relationship between SEP and cardiovascular health.

Reproducibility of serum cytokines and growth factors

BACKGROUND

In most studies, circulating biomarkers are usually assessed from a single sample, assuming that this single measurement represents the long-term biomarker status of the individual. Such an assumption is rarely tested although it may not be valid for all biomarkers. The objective of this study was to investigate the temporal reproducibility of a panel of cytokines and growth factors.

METHODS

Thirty-five postmenopausal women with two annual visits and 30 premenopausal women with three annual visits were randomly selected from the participants in an existing prospective cohort. A total of 23 serum cytokines, nine growth factors and C-reactive protein (CRP) were measured using the Luminex xMap technology. In addition, for eight biomarkers, regular and high sensitivity (hs) assays were compared.

RESULTS

The biomarkers with adequate (>60%) detection rates and acceptable (> or =0.55) intra-class correlation coefficients (ICCs) were: hsIL-1beta, IL-1RA, hsIL-2, hsIL-4, hsIL-5, hsIL-6, hsIL-10, IL-12p40, hsIL-12p70, hsTNF-alpha, TNF-R1, TNF-R2, CRP, HGF, NGF, and EGFR. The remaining biomarkers either had low temporal reproducibility or were undetectable in more than 40% of samples.

CONCLUSIONS

The results suggest that 16 of the 41 biomarkers measured with Luminex technology showed sufficient sensitivity and temporal reproducibility in sera.

Inflammatory markers and cognitive function in middle-aged adults: the Whitehall II study

OBJECTIVES

To assess whether C-reactive protein (CRP) and interleukin-6 (IL-6) are associated with low cognitive performance and decline in middle-aged adults.

DESIGN/SETTING

The Whitehall II study; an ongoing large-scale, prospective occupational cohort study of employees from 20 London-based white-collar Civil Service departments.

PARTICIPANTS

Data from more than 3000 males and 1200 female employees.

MEASURES

Inflammatory makers measured in 1991-1993 and five cognitive tests (short-term verbal memory, inductive reasoning (AH4-I), vocabulary (Mill Hill), and phonemic and semantic fluency) performed in 1997-1999 and 2002-2004. Performance in the lowest sex-specific quintile indicated low cognitive performance or decline. Covariates included sociodemographics, health behaviours and health conditions.

RESULTS

In age-adjusted analyses both CRP and IL-6 were associated with all cognitive measures in 1997-1999, even though the association with memory was not consistent. After extensive adjustment raised CRP levels were only associated with poor cognitive performance on the AH4-I (OR=1.38; 95% CI: 1.05-1.82) and Mill Hill (OR=1.52; 95% CI: 1.14-2.03) and IL-6 on semantic fluency (OR=1.27; 95% CI: 1.14-2.03). Associations were more evident in men than in women. No clear relationship was observed for decline.

CONCLUSIONS

Our results suggest that raised levels of inflammatory markers in midlife are moderately associated with lower cognitive status, but little with cognitive decline.

Interleukin-6 covaries inversely with hippocampal grey matter volume in middle-aged adults

BACKGROUND

Converging animal findings suggest that higher peripheral levels of inflammation are associated with activation of central inflammatory mechanisms that result in hippocampal neurodegeneration and related impairment of memory function. We have recently shown, consistent with animal findings, an inverse association between peripheral levels of interleukin-6 (IL-6), a relatively stable marker of systemic inflammation, and memory function in mid-life adults. In the current study, we extend this work to test whether systemic inflammation is associated with reduced grey matter volume of the hippocampus.

METHODS

For this purpose, we used a computational structural neuroimaging method (optimized voxel-based morphometry) to evaluate the relationship between plasma IL-6 levels and hippocampal grey matter volume in a sample of 76 relatively healthy community volunteers ages 30-54.

RESULTS

Peripheral levels of IL-6 covaried inversely with hippocampal grey matter volume, and this relationship persisted after accounting for several possible confounders, including age, gender, race, years of education, percent body fat, blood pressure, smoking, physical activity, hours of sleep, alcohol use, and total grey matter volume.

CONCLUSIONS

To our knowledge, this is the first report of a relationship between a peripheral marker of IL-6 and hippocampal grey matter volume, raising the possibility that low-grade systemic inflammation could plausibly presage subclinical cognitive decline in part via structural neural pathways.

Community socioeconomic status is associated with circulating interleukin-6 and C-reactive protein

OBJECTIVE

To examine the association of both individual and community socioeconomic status (SES) with inflammatory mediators relevant to cardiovascular pathophysiology, i.e., interleukin (IL)-6 and C-reactive protein (CRP), in a midlife community sample. Growing evidence suggests that socioeconomic attributes of both individuals and communities confer risk for cardiovascular morbidity and mortality.

METHODS

Subjects were 851 men and women, 30 to 54 years of age (Caucasian = 77%, African-American = 23%). Individual SES was indexed by a composite of educational attainment and family income, and community SES was indexed by corresponding indicators derived from US Census data for participants' census tracts of residence. Plasma concentrations of IL-6 and CRP were determined from blood samples.

RESULTS

Regression analyses adjusting for age, sex, and race showed individual SES to be associated inversely with IL-6 (B = -0.126, p < .01), and community SES to be associated inversely with both IL-6 and CRP (B = -0.144, p < .01, B = -0.097, p < .01, respectively). The relationship of community SES with IL-6, but not CRP, persisted on multivariable adjustment for both lifestyle risk factors (smoking, alcohol consumption, sleep, exercise, body mass index) and individual SES (IL-6: B = -0.084, p < .05; CRP: B = -0.047, p > .10). After adjustment for lifestyle factors, however, individual SES was no longer associated with IL-6.

CONCLUSIONS

Independent of personal income or educational attainment, midlife adults living in less advantaged neighborhoods exhibit higher levels of circulating proinflammatory markers than residents of more affluent areas. This association may help explain the increased risk of atherosclerotic cardiovascular morbidity and mortality conferred by low community-level SES.

Antagonistic characteristics are positively associated with inflammatory markers independently of trait negative emotionality

Recent evidence suggests that individuals with certain personality traits are at elevated risk for chronic systemic inflammation. To date, this literature has focused on the related traits of hostility and negative affect (NA). In this study, we examine the covariation of trait measures of hostility and NA with the inflammatory mediators interleukin-6 and C-reactive protein. We also explore whether observed associations reflect independent contributions of cognitive, affective and behavioral components of hostile dispositions or shared trait variance with global negative affectivity. Subjects were a diverse sample of 855 relatively healthy middle-aged community volunteers (50% male) from the Adult Health and Behavior Project. The Buss and Perry Aggression Questionnaire (BPAQ) and an Abbreviated Cook-Medley Hostility Scale (ACM) were used to measure dimensions of hostility, and the Multidimensional Personality Questionnaire was used to measure trait NA. Regression analyses accounting for demographic characteristics and medical covariates showed a positive relationship of all components of hostility and trait NA with both IL-6 and CRP. After controlling for trait NA, only the behavioral component of hostility was independently associated with the inflammatory markers. The relationships of cognitive and affective components of hostility with inflammatory markers were largely explained by lifestyle factors, particularly body mass index and smoking. In contrast, lifestyle factors did not explain the covariation of hostile behavioral tendencies and inflammation. These findings suggest that unique attributes of aggressive behavioral tendencies account for much of the variability in inflammation associated with hostility and negative emotions, raising the possibility that individuals high in aggression are at increased risk of inflammatory disease.

Caregiving, repetitive thought, and immune response to vaccination in older adults

Chronic stressors such as caregiving have been associated with reduced antibody production after vaccination and elevated interleukin (IL)-6 in older adults. However, individual differences in repetitive thought, that is, frequent or prolonged thought about oneself and one's world, can modify perception and effects of stress. For example, worry during stressful circumstances has been associated with poorer immune outcomes, whereas cognitive processing has been associated with better outcomes. The present study tested the relationship of caregiving and two types of repetitive thought, negative (e.g., worry) and neutral (e.g., reflection), to pre- and post-influenza vaccine antibody and IL-6. Dementia caregivers (n=14) and controls (n=30) were interviewed and had blood drawn pre- and post-vaccine in a multi-wave study. Multi-level models found that caregivers had higher IL-6 than controls after vaccination (t(23)=2.36, p<.05). There were several interactions between caregiver status and repetitive thought in predicting both depression and immune responses to vaccination. Among caregivers, negative repetitive thought predicted more depression and lower antibody titers, whereas neutral repetitive thought predicted less depression and higher antibody titers, but also higher post-vaccination IL-6. Among controls, negative repetitive thought predicted more depression but higher antibody titers, whereas neutral repetitive thought predicted less depression and lower post-vaccination IL-6. In mediational tests, depression did not account for the effects of repetitive thought. Results generally support beneficial effects of neutral repetitive thought and detrimental effects of negative repetitive thought, but those effects may be reduced or even reversed depending on life circumstances.

Do psychological factors affect inflammation and incident coronary heart disease: the Whitehall II Study

OBJECTIVE

The purpose of this study was to test whether psychological factors affect inflammation processes to an extent that increases the risk of coronary heart disease (CHD).

METHODS AND RESULTS

We used data from 6396 civil servants (4453 men, 1943 women) from the Whitehall II Study, aged 35 to 55 years and free from clinically validated CHD at the start of the follow-up period. Two psychological factors were assessed at phase 1 (1985 to 1988) and phase 2 (1989 to 1990): negative affect and psychological distress. Inflammatory biomarkers (fibrinogen, high-sensitivity C-reactive- protein, interleukin-6) and 12 baseline covariates including biological and behavioral CHD risk factors, sociodemographic variables, and work stress were measured at phase 3 (1991 to 1993). Follow-up for CHD death, first nonfatal myocardial infarction, or definite angina occurring between phase 3 and phase 7 (2003 to 2004) was based on clinical records. Higher levels of inflammatory markers were associated with higher CHD incidence, with hazard ratios (HR) ranging from 1.31 to 2.37 in age-and sex-adjusted models. Higher levels of negative affectivity and psychological distress were not associated with greater concentrations of inflammatory markers. Negative affectivity (relative index of inequality=1.68, 95% confidence interval [CI] 1.20 to 2.36) and higher psychological distress exposure (HR=1.66, 95% CI 1.28 to 2.14) were associated with higher CHD incidence and these associations remained unchanged after adjustment for inflammatory markers.

CONCLUSIONS

Our findings suggest that psychological factors do not affect inflammation although they predict incident CHD.

Common genetic variants associated with plasma fibrin D-dimer concentration in older European- and African-American adults

BACKGROUND AND OBJECTIVES

D-dimer is a hemostasis marker that reflects ongoing fibrin formation and degradation. There is significant inter-individual and inter-population variability in D-dimer concentration, but whether genetic factors underlie these differences is largely unknown. We hypothesized that common coagulation gene variants contribute to differences in circulating D-dimer concentration.

METHODS

The setting was European-American (EA; n = 1858) and African-American (AA; n = 327) unrelated older adults from the Cardiovascular Health Study (CHS), in which we genotyped SNPs in 42 genes related to blood coagulation and fibrinolysis.

RESULTS

Several fibrinogen gene polymorphisms, including the Thr312Ala Aalpha chain variant and the FGG-10034 C/T variant, were associated with approximately 20% higher plasma D-dimer levels in EA (false discovery rate < 5% for covariate-adjusted model). There was also some evidence that a Pro41Leu variant of the PLAU gene encoding urinary plasminogen activator and non-coding polymorphism of the plasminogen activator inhibitor type 1 gene (SERPINE1) were associated with higher plasma D-dimer in EA. There were no significant associations between the studied coagulation or fibrinolysis gene SNPs and plasma D-dimer levels in the smaller AA sample. However, each standard deviation increase in European ancestry assessed by ancestry-informative gene markers was associated with approximately 10% lower mean D-dimer levels in AA.

CONCLUSIONS

Together, common coagulation/fibrinolysis gene SNPs explained only approximately 2% of the variance in plasma D-dimer levels in EA. These findings suggest that the association of D-dimer with risk of vascular outcomes may be mediated largely by environmental factors, other genes, and/or genetic interactions.

Inflammatory markers in late-life depression: results from a population-based study

BACKGROUND

Previous studies have reported conflicting results concerning the association between several inflammatory markers and depression. The association between inflammation and depression may depend on the presence of specific chronic diseases or be relevant in specific sub-groups of depressed patients only.

OBJECTIVE

To assess associations between inflammatory markers and depression in older people, taking account of confounding and effect-modifying factors.

METHOD

Population-based study of 1285 participants of the Longitudinal Aging Study Amsterdam, aged 65 and over. Plasma concentrations of Interleukin-6 (IL-6) and C-reactive protein (CRP) were measured. Major depression (first- or recurrent episode) and sub-threshold depression were assessed. Associations were adjusted for confounding variables. Associations with inflammatory markers were further studied with regard to severity and duration of depression, and with regard to specific depressive symptoms.

RESULTS

High levels of IL-6 (above 5 pg/mL) were associated with major depression (odds ratio 2.49 (1.07-5.80), both in recurrent and first episodes. No significant effect of either one of the markers on specific symptom dimensions of depression was found. Mildly elevated plasma levels of CRP (above 3.2 mg/L) were associated with higher CES-D scores, but not after correction for the confounding effect of age and chronic diseases.

LIMITATIONS

The cross-sectional design limits conclusions regarding causality.

CONCLUSIONS

A high plasma level of IL-6, but not CRP, is associated with an increased prevalence of major depression in older people, independent of age, chronic diseases, cognitive functioning and anti-depressants. Present results suggest new directions for clinical research into the prevention of physical consequences of depression.

Geographical segregation and IL-6: a marker of chronic inflammation in older adults

AIM: To examine environmental sociodemographic risks of high IL-6, a marker of chronic inflammation in older adults. METHODS: We spatially linked 1990 USA Census tract demographic and economic measures to a prospective cohort study of representative community residents aged 71 years and older, from over 1700 of whom a cytokine protein and biological marker of chronic inflammation. IL-6, was collected. Using generalized interactive mixed models, we modeled 1989-1990 individual and census level risk factors for the dependent variable high IL-6 between 1992-1993 (high IL-6 = upper quartile: >2.96 pg/ml). RESULTS: After individual health risk adjustment, IL-6 remained elevated in communities with greater densities of poor older adults (odd ratio [OR]: 1.25 per 10% increase in exposure. 95% confidence interval [CI]: 1.05, 1.48) and in racially segregated communities (OR: 1.14 per 10% increase in exposure. 95% CI: 1.04, 1.25). CONCLUSIONS: Socially disadvantaged environments may influence IL-6, a biomarker of age-associated inflammation.

Identification and treatment of symptoms associated with inflammation in medically ill patients

Medically ill patients present with a high prevalence of non-specific comorbid symptoms including pain, sleep disorders, fatigue and cognitive and mood alterations that is a leading cause of disability. However, despite major advances in the understanding of the immune-to-brain communication pathways that underlie the pathophysiology of these symptoms in inflammatory conditions, little has been done to translate this newly acquired knowledge to the clinics and to identify appropriate therapies. In a multidisciplinary effort to address this problem, clinicians and basic scientists with expertise in areas of inflammation, psychiatry, neurosciences and psychoneuroimmunology were brought together in a specialized meeting organized in Bordeaux, France, on May 28-29, 2007. These experts considered key questions in the field, in particular those related to identification and quantification of the predominant symptoms associated with inflammation, definition of systemic and central markers of inflammation, possible domains of intervention for controlling inflammation-associated symptoms, and relevance of animal models of inflammation-associated symptoms. This resulted in a number of recommendations that should improve the recognition and management of inflammation-associated symptoms in medically ill patients.