Interleukin-8 is associated with increased total mortality in women but not in men-findings from a community-based cohort of elderly

Chemokine CXCL9, a marker of inflammaging, is associated with changes of muscle strength and mortality in older men

Our study examined associations of the CXC motif chemokine ligand 9 (CXCL9), a pro-inflammatory protein implicated in age-related inflammation, with musculoskeletal function in elderly men. We found in certain outcomes both cross-sectional and longitudinal significant associations of CXCL9 with poorer musculoskeletal function and increased mortality in older men. This requires further investigation.

PURPOSE

We aim to determine the relationship of (CXCL9), a pro-inflammatory protein implicated in age-related inflammation, with both cross-sectional and longitudinal musculoskeletal outcomes and mortality in older men.

METHODS

A random sample from the Osteoporotic Fractures in Men (MrOS) Study cohort (N = 300) was chosen for study subjects that had attended the third and fourth clinic visits, and data was available for major musculoskeletal outcomes (6 m walking speed, chair stands), hip bone mineral density (BMD), major osteoporotic fracture, mortality, and serum inflammatory markers. Serum levels of CXCL9 were measured by ELISA, and the associations with musculoskeletal outcomes were assessed by linear regression and fractures and mortality with Cox proportional hazards models.

RESULTS

The mean CXCL9 level of study participants (79.1 ± 5.3 years) was 196.9 ± 135.2 pg/ml. There were significant differences for 6 m walking speed, chair stands, physical activity scores, and history of falls in the past year across the quartiles of CXCL9. However, higher CXCL9 was only significantly associated with changes in chair stands (β =  - 1.098, p < 0.001) even after adjustment for multiple covariates. No significant associations were observed between CXCL9 and major osteoporotic fracture or hip BMD changes. The risk of mortality increased with increasing CXCL9 (hazard ratio quartile (Q)4 vs Q1 1.98, 95% confidence interval 1.25-3.14; p for trend < 0.001).

CONCLUSIONS

Greater serum levels of CXCL9 were significantly associated with a decline in chair stands and increased mortality. Additional studies with a larger sample size are needed to confirm our findings.

Immunity in the Progeroid Model of Cockayne Syndrome: Biomarkers of Pathological Aging

Cockayne syndrome (CS) is a rare autosomal recessive disorder that affects the DNA repair process. It is a progeroid syndrome predisposing patients to accelerated aging and to increased susceptibility to respiratory infections. Here, we studied the immune status of CS patients to determine potential biomarkers associated with pathological aging. CS patients, as well as elderly and young, healthy donors, were enrolled in this study. Complete blood counts for patients and donors were assessed, immune cell subsets were analyzed using flow cytometry, and candidate cytokines were analyzed via multi-analyte ELISArray kits. In CS patients, we noticed a high percentage of lymphocytes, an increased rate of intermediate and non-classical monocytes, and a high level of pro-inflammatory cytokine IL-8. In addition, we identified an increased rate of particular subtypes of T Lymphocyte CD8+ CD28- CD27-, which are senescent T cells. Thus, an inflammatory state was found in CS patients that is similar to that observed in the elderly donors and is associated with an immunosenescence status in both groups. This could explain the CS patients' increased susceptibility to infections, which is partly due to an aging-associated inflammation process.

Causal analysis of plasma IL-8 on carotid intima media thickness, a measure of subclinical atherosclerosis

BACKGROUND

We investigated the causality of IL-8 on carotid intima-media thickness (c-IMT), a measure of sub-clinical atherosclerosis.

METHODS

The IMPROVE is a multicenter European study (n = 3,711). The association of plasma IL-8 with c-IMT (mm) was estimated by quantile regression. Genotyping was performed using the Illumina CardioMetabo and Immuno chips. Replication was attempted in three independent studies and a meta-analysis was performed using a random model.

RESULTS

In IMPROVE, each unit increase in plasma IL-8 was associated with an increase in median c-IMT measures (all p<0·03) in multivariable analyses. Linear regression identified rs117518778 and rs8057084 as associated with IL-8 levels and with measures of c-IMT. The two SNPs were combined in an IL-8-increasing genetic risk that showed causality of IL-8 on c-IMT in IMPROVE and in the UK Biobank (n = 22,179). The effect of IL-8 on c-IMT measures was confirmed in PIVUS (n = 1,016) and MDCCC (n = 6,103). The association of rs8057084 with c-IMT was confirmed in PIVUS and UK Biobank with a pooled estimate effect (β) of -0·006 with 95%CI (-0·008- -0·003).

CONCLUSION

Our results indicate that genetic variants associated with plasma IL-8 also associate with c-IMT. However, we cannot infer causality of this association, as these variants lie outside of the IL8 locus.

Kinetics of inflammatory biomarkers to predict one-year mortality in older patients hospitalized for pneumonia: a multivariable analysis

OBJECTIVES

Long-term mortality is increased in older patients with pneumonia. We aimed to test whether residual inflammation is predictive of one-year mortality after pneumonia.

METHODS

Inflammation biomarkers (C-reactive protein [CRP], interleukin [IL]-6 and IL-8, tumor necrosis factor-α, serum amyloid A, neopterin, myeloperoxidase, anti-apolipoprotein A-1, and anti-phosphorylcholine IgM) were measured at admission and discharge in older patients hospitalized for pneumonia in a prospective study. Univariate and multivariate analyses were conducted using absolute level at discharge and relative and absolute differences between admission and discharge for all biomarkers, along with usual prognostic factors.

RESULTS

In the 133 included patients (median age, 83 years [interquartile range: 78-89]), one-year mortality was 26%. In univariate analysis, the relative difference of CRP levels had the highest area under the receiver operating characteristic curve (0.70; 95% confidence interval [CI] 0.60-0.80). A decrease of CRP levels of more than 67% between admission and discharge had 68% sensitivity and 68% specificity to predict survival. In multivariate analysis, lower body mass index (hazard ratio=0.87 [CI 95% 0.79-0.96], P-value=0.01), higher IL-8 (hazard ratio=1.02 [CI 95% 1.00-1.04], P-value=0.02), and higher CRP (1.01 [95% CI 1.00-1.02], P=0.01) at discharge were independently associated with mortality.

CONCLUSION

Higher IL-8 and CRP levels at discharge were independently associated with one-year mortality. The relative CRP difference during hospitalization was the best individual biomarker for predicting one-year mortality.

The effect of a 6-month ketogenic medium-chain triglyceride supplement on plasma cardiometabolic and inflammatory markers in mild cognitive impairment

INTRODUCTION

Mild cognitive impairment (MCI) is often accompanied by metabolic abnormalities and inflammation that might play a role in the development of cognitive impairment. The use of ketogenic medium-chain triglycerides (kMCT) to improve cognition in this population has shown promising results but remains controversial because of the potentially detrimental effect of elevated intake of saturated fatty acids on cardiovascular (CV) health and perhaps inflammatory processes. The primary aim of this secondary data analysis report is to describe changes in cardiometabolic markers and peripheral inflammation during a 6-month kMCT intervention in MCI.

METHODS

Thirty-nine participants with MCI completed the intervention of 30 g/day of either a kMCT drink or calorie-matched placebo (high-oleic acid) for 6 months. Plasma concentrations of cardiometabolic and inflammatory markers were collected before (fasting state) and after the intervention (2 h following the last drink).

RESULTS

A mixed model ANOVA analysis revealed a time by group interaction for ketones (P < 0.001), plasma 8:0 and 10:0 acids (both P < 0.001) and IL-8 (P = 0.002) with follow up comparison revealing a significant increase in the kMCT group (+48%, P = 0.005), (+3,800 and +4,900%, both P < 0.001) and (+147%, P < 0.001) respectively. A main effect of time was observed for insulin (P = 0.004), triglycerides (P = 0.011) and non-esterified fatty acids (P = 0.036).

CONCLUSION

Under these study conditions, 30 g/d of kMCT taken for six months and up to 2-hour before post-intervention testing had minimal effect on an extensive profile of circulating cardiometabolic and inflammatory markers as compared to a placebo calorie-matched drink. Our results support the safety kMCT supplementation in individuals with MCI. The clinical significance of the observed increase in circulating IL-8 levels is presently unknown and awaits future studies.

Serum IL8 is not associated with cardiovascular events but with all-cause mortality

BACKGROUND

The aim of this study is to investigate if IL8 levels were associated with incident cardiovascular (CV) events (CVE) and mortality (all-cause, CV, and cancer) in a cohort of 60 years old men and women from Stockholm (60YO).

METHODS

The 60YO comprises 4232 participants; baseline period: 1997-1999. The cohort is matched annually to population registries to record deaths and incident CVE. Serum IL8 was measured in 4011 participants and categorized in quartiles. Cox proportional hazard models were used to estimate the CVE and mortality risk, expressed as hazard ratios (HR) with 95% confidence intervals (CI). Potential confounding was addressed by adjusting for traditional CV risk factors (CVE estimates) and by sex, life style habits, metabolic factors (mortality estimates). Laplace regression was used to calculate the difference in time until a certain percentage of the cohort died according to IL8 levels.

RESULTS

During 16.5 years follow up, 522 incident CVE were recorded and 647 study participants died. IL8 was not associated with CVE risk (IL8 Q4 vs Q1, HR of 0.95; 95% CI 0.75-1.22). Compared to Q1, IL8 Q4 was associated with all-cause mortality (adjusted HR 1.28; 95% CI 1.02-1.63). No association was observed with CV and cancer related mortality in the fully adjusted model. Participants with IL8 above the median died of any cause ≈1.3 years before the 15% of the population had died.

CONCLUSION

Elevated IL8 levels were not associated with CVE risk and CV mortality, but were associated with an increased risk of all-cause mortality regardless of the underlying cause.

Predictive value of multiple cytokines and chemokines for mortality in an admixed population: 15-year follow-up of the Bambui-Epigen (Brazil) cohort study of aging

Inflammation, particularly elevated IL-6 serum levels, has been associated with increased mortality risk, mostly in Caucasians. The influence of genetic ethno-racial background on this association is unknown. We examined associations between baseline serum levels of Interleukin-6 (IL-6) and other cytokines (IL1-2, TNF, IL-10, and IL1β) and chemokines (CCL2, CCL5, CXCL8, CXCL9 and CXCL10) with 15-year mortality in 1,191 admixed Brazilians aged 60years and over. Elevated IL6 level (but not other biomarkers) was associated with increased risk of deaths with fully adjusted hazard ratios of 1.51 (95% CI=1.15, 1.97), 1.54 (95% CI=1.20, 1.96) and 1.79 (95% CI=1.40, 2.29) for the 2nd, 3rd and the highest quartiles, respectively. Genomic African and Native American proportions did not modify the association (p>0.05). The discriminatory ability to predict death of a model based on IL-6 alone was similar as that of a comprehensive morbidity score (C statistics=0.59 and 0.60, respectively). The abilities of IL-6 and the morbidity score models to predict death remained stable for very long term after the baseline measurement. Our results indicate that genome-based African and Native American ancestries have no impact on the prognostic value of IL-6 for mortality.