Accelerometer-based physical activity is associated with the gut microbiota in 8416 individuals in SCAPIS

BACKGROUND

Previous population-based studies investigating the relationship between physical activity and the gut microbiota have relied on self-reported activity, prone to reporting bias. Here, we investigated the associations of accelerometer-based sedentary (SED), moderate-intensity (MPA), and vigorous-intensity (VPA) physical activity with the gut microbiota using cross-sectional data from the Swedish CArdioPulmonary bioImage Study.

METHODS

In 8416 participants aged 50-65, time in SED, MPA, and VPA were estimated with hip-worn accelerometer. Gut microbiota was profiled using shotgun metagenomics of faecal samples. We applied multivariable regression models, adjusting for sociodemographic, lifestyle, and technical covariates, and accounted for multiple testing.

FINDINGS

Overall, associations between time in SED and microbiota species abundance were in opposite direction to those for MPA or VPA. For example, MPA was associated with lower, while SED with higher abundance of Escherichia coli. MPA and VPA were associated with higher abundance of the butyrate-producers Faecalibacterium prausnitzii and Roseburia spp. We observed discrepancies between specific VPA and MPA associations, such as a positive association between MPA and Prevotella copri, while no association was detected for VPA. Additionally, SED, MPA and VPA were associated with the functional potential of the microbiome. For instance, MPA was associated with higher capacity for acetate synthesis and SED with lower carbohydrate degradation capacity.

INTERPRETATION

Our findings suggest that sedentary and physical activity are associated with a similar set of gut microbiota species but in opposite directions. Furthermore, the intensity of physical activity may have specific effects on certain gut microbiota species.

FUNDING

European Research Council, Swedish Heart-Lung Foundation, Swedish Research Council, Knut and Alice Wallenberg Foundation.

Streptococcus Species Abundance in the Gut Is Linked to Subclinical Coronary Atherosclerosis in 8973 Participants From the SCAPIS Cohort

BACKGROUND

Gut microbiota have been implicated in atherosclerotic disease, but their relation with subclinical coronary atherosclerosis is unclear. This study aimed to identify associations between the gut microbiome and computed tomography-based measures of coronary atherosclerosis and to explore relevant clinical correlates.

METHODS

We conducted a cross-sectional study of 8973 participants (50 to 65 years of age) without overt atherosclerotic disease from the population-based SCAPIS (Swedish Cardiopulmonary Bioimage Study). Coronary atherosclerosis was measured using coronary artery calcium score and coronary computed tomography angiography. Gut microbiota species abundance and functional potential were assessed with shotgun metagenomics sequencing of fecal samples, and associations with coronary atherosclerosis were evaluated with multivariable regression models adjusted for cardiovascular risk factors. Associated species were evaluated for association with inflammatory markers, metabolites, and corresponding species in saliva.

RESULTS

The mean age of the study sample was 57.4 years, and 53.7% were female. Coronary artery calcification was detected in 40.3%, and 5.4% had at least 1 stenosis with >50% occlusion. Sixty-four species were associated with coronary artery calcium score independent of cardiovascular risk factors, with the strongest associations observed for Streptococcus anginosus and Streptococcus oralis subsp oralis (P<1×10-5). Associations were largely similar across coronary computed tomography angiography-based measurements. Out of the 64 species, 19 species, including streptococci and other species commonly found in the oral cavity, were associated with high-sensitivity C-reactive protein plasma concentrations, and 16 with neutrophil counts. Gut microbial species that are commonly found in the oral cavity were negatively associated with plasma indole propionate and positively associated with plasma secondary bile acids and imidazole propionate. Five species, including 3 streptococci, correlated with the same species in saliva and were associated with worse dental health in the Malmö Offspring Dental Study. Microbial functional potential of dissimilatory nitrate reduction, anaerobic fatty acid β-oxidation, and amino acid degradation were associated with coronary artery calcium score.

CONCLUSIONS

This study provides evidence of an association of a gut microbiota composition characterized by increased abundance of Streptococcus spp and other species commonly found in the oral cavity with coronary atherosclerosis and systemic inflammation markers. Further longitudinal and experimental studies are warranted to explore the potential implications of a bacterial component in atherogenesis.

OSA Is Associated With the Human Gut Microbiota Composition and Functional Potential in the Population-Based Swedish CardioPulmonary bioImage Study

BACKGROUND

OSA is a common sleep-breathing disorder linked to increased risk of cardiovascular disease. Intermittent upper airway obstruction and hypoxia, hallmarks of OSA, have been shown in animal models to induce substantial changes to the gut microbiota composition, and subsequent transplantation of fecal matter to other animals induced changes in BP and glucose metabolism.

RESEARCH QUESTION

Does OSA in adults associate with the composition and functional potential of the human gut microbiota?

STUDY DESIGN AND METHODS

We used respiratory polygraphy data from up to 3,570 individuals 50 to 64 years of age from the population-based Swedish Cardiopulmonary bioimage Study combined with deep shotgun metagenomics of fecal samples to identify cross-sectional associations between three OSA parameters covering apneas and hypopneas, cumulative sleep time in hypoxia, and number of oxygen desaturation events with gut microbiota composition. Data collection about potential confounders was based on questionnaires, onsite anthropometric measurements, plasma metabolomics, and linkage with the Swedish Prescribed Drug Register.

RESULTS

We found that all three OSA parameters were associated with lower diversity of species in the gut. Furthermore, in multivariable-adjusted analysis, the OSA-related hypoxia parameters were associated with the relative abundance of 128 gut bacterial species, including higher abundance of Blautia obeum and Collinsella aerofaciens. The latter species was also independently associated with increased systolic BP. Furthermore, the cumulative time in hypoxia during sleep was associated with the abundance of genes involved in nine gut microbiota metabolic pathways, including propionate production from lactate. Finally, we observed two heterogeneous sets of plasma metabolites with opposite association with species positively and negatively associated with hypoxia parameters, respectively.

INTERPRETATION

OSA-related hypoxia, but not the number of apneas/hypopneas, is associated with specific gut microbiota species and functions. Our findings lay the foundation for future research on the gut microbiota-mediated health effects of OSA.

Ambient air pollution and inflammation-related proteins during early childhood

BACKGROUND AND AIM

Experimental studies show that short-term exposure to air pollution may alter cytokine concentrations. There is, however, a lack of epidemiological studies evaluating the association between long-term air pollution exposure and inflammation-related proteins in young children. Our objective was to examine whether air pollution exposure is associated with inflammation-related proteins during the first 2 years of life.

METHODS

In a pooled analysis of two birth cohorts from Stockholm County (n = 158), plasma levels of 92 systemic inflammation-related proteins were measured by Olink Proseek Multiplex Inflammation panel at 6 months, 1 year and 2 years of age. Time-weighted average exposure to particles with an aerodynamic diameter of <10 μm (PM₁₀), <2.5 μm (PM_2.5), and nitrogen dioxide (NO₂) at residential addresses from birth and onwards was estimated via validated dispersion models. Stratified by sex, longitudinal cross-referenced mixed effect models were applied to estimate the overall effect of preceding air pollution exposure on combined protein levels, "inflammatory proteome", over the first 2 years of life, followed by cross-sectional protein-specific bootstrapped quantile regression analysis.

RESULTS

We identified significant longitudinal associations of inflammatory proteome during the first 2 years of life with preceding PM_2.5 exposure, while consistent associations with PM₁₀ and NO₂ across ages were only observed among girls. Subsequent protein-specific analyses revealed significant associations of PM₁₀ exposure with an increase in IFN-gamma and IL-12B in boys, and a decrease in IL-8 in girls at different percentiles of proteins levels, at age 6 months. Several inflammation-related proteins were also significantly associated with preceding PM₁₀, PM_2.5 and NO₂ exposures, at ages 1 and 2 years, in a sex-specific manner.

CONCLUSIONS

Ambient air pollution exposure influences inflammation-related protein levels already during early childhood. Our results also suggest age- and sex-specific differences in the impact of air pollution on children's inflammatory profiles.

An online atlas of human plasma metabolite signatures of gut microbiome composition

Human gut microbiota produce a variety of molecules, some of which enter the bloodstream and impact health. Conversely, dietary or pharmacological compounds may affect the microbiota before entering the circulation. Characterization of these interactions is an important step towards understanding the effects of the gut microbiota on health. In this cross-sectional study, we used deep metagenomic sequencing and ultra-high-performance liquid chromatography linked to mass spectrometry for a detailed characterization of the gut microbiota and plasma metabolome, respectively, of 8583 participants invited at age 50 to 64 from the population-based Swedish CArdioPulmonary bioImage Study. Here, we find that the gut microbiota explain up to 58% of the variance of individual plasma metabolites and we present 997 associations between alpha diversity and plasma metabolites and 546,819 associations between specific gut metagenomic species and plasma metabolites in an online atlas (https://gutsyatlas.serve.scilifelab.se/). We exemplify the potential of this resource by presenting novel associations between dietary factors and oral medication with the gut microbiome, and microbial species strongly associated with the uremic toxin p-cresol sulfate. This resource can be used as the basis for targeted studies of perturbation of specific metabolites and for identification of candidate plasma biomarkers of gut microbiota composition.

Here, Dekkers et al. characterize associations of 1528 gut metagenomic species with the plasma metabolome in 8583 participants of the SCAPIS Study, and find that gut microbiota explain up to 58% of the variance of individual plasma metabolites.

Evening chronotype is associated with elevated biomarkers of cardiometabolic risk in the EpiHealth cohort: a cross-sectional study

STUDY OBJECTIVES

Individuals with evening chronotype have a higher risk of cardiovascular and metabolic disorders, although the underlying mechanisms are not well understood. In a population-based cohort, we aimed to investigate the association between chronotype and 242 circulating proteins from three panels of established or candidate biomarkers of cardiometabolic processes.

METHODS

In 2,471 participants (49.7% men, mean age 61.2±8.4 SD years) from the EpiHealth cohort, circulating proteins were analyzed with a multiplex proximity extension technique. Participants self-reported their chronotype on a five-level scale from extreme morning to extreme evening chronotype. With the intermediate chronotype set as the reference, each protein was added as the dependent variable in a series of linear regression models adjusted for confounders. Next, the chronotype coefficients were jointly tested and the resulting p-values adjusted for multiple testing using false discovery rate (5%). For the associations identified, we then analyzed the marginal effect of each chronotype category.

RESULTS

We identified 17 proteins associated with chronotype. Evening chronotype was positively associated with proteins previously linked to insulin resistance and cardiovascular risk, namely retinoic acid receptor protein 2, fatty acid-binding protein adipocyte, tissue-type plasminogen activator, and plasminogen activator inhibitor 1 (PAI-1). Additionally, PAI-1 was inversely associated with the extreme morning chronotype.

CONCLUSIONS

In this population-based study, proteins previously related with cardiometabolic risk were elevated in the evening chronotypes. These results may guide future research in the relation between chronotype and cardiometabolic disorders.

The relationship of indoxyl sulfate and p-cresyl sulfate with target cardiovascular proteins in hemodialysis patients

Protein-bound uremic toxins (Indoxyl sulfate [IS] and p-cresyl sulfate [PCS]) are both associated with cardiovascular (CV) and all-cause mortality in subjects with chronic kidney disease (CKD). Possible mechanisms have not been elucidated. In hemodialysis patients, we investigated the relationship between the free form of IS and PCS and 181 CV-related proteins. First, IS or PCS concentrations were checked, and high levels were associated with an increased risk of acute coronary syndrome (ACS) in 333 stable HD patients. CV proteins were further quantified by a proximity extension assay. We examined associations between the free form protein-bound uremic toxins and the quantified proteins with correction for multiple testing in the discovery process. In the second step, the independent association was evaluated by multivariable-adjusted models. We rank the CV proteins related to protein-bound uremic toxins by bootstrapped confidence intervals and ascending p-value. Six proteins (signaling lymphocytic activation molecule family member 5, complement component C1q receptor, C–C motif chemokine 15 [CCL15], bleomycin hydrolase, perlecan, and cluster of differentiation 166 antigen) were negatively associated with IS. Fibroblast growth factor 23 [FGF23] was the only CV protein positively associated with IS. Three proteins (complement component C1q receptor, CCL15, and interleukin-1 receptor-like 2) were negatively associated with PCS. Similar findings were obtained after adjusting for classical CV risk factors. However, only higher levels of FGF23 was related to increased risk of ACS. In conclusion, IS and PCS were associated with several CV-related proteins involved in endothelial barrier function, complement system, cell adhesion, phosphate homeostasis, and inflammation. Multiplex proteomics seems to be a promising way to discover novel pathophysiology of the uremic toxin.

Risk factors for vascular catheter-related bloodstream infections in pediatric intensive care units

Objectives

To determine the risk factors for acquiring central line-associated blood stream infections (CLABSI) in pediatric intensive care units and to investigate the incidence and etiology of CLABSI in pediatric intensive care units with different profiles.

Methods

The study was a prospective cohort study in three hospitals. One of the hospitals is a large metropolitan public hospital with two pediatric intensive care units and a total of nineteen pediatric intensive care unit beds, another is a regional hospital with eight pediatric intensive care unit beds, and the third is a private hospital with fifteen beds. Patients between the ages of 1 month old and 18 years old who used a central venous catheter for over 24 hours were included. We recorded patients’ daily progress. General patient and catheter-related data were collected and used as variables. All the data were analyzed using Statistical Package for Social Science (SPSS), version 13.0, to compare patients with CLABSI with or without risk factors.

Results

A total of 728 patients were admitted to the pediatric intensive care units, and 170 had a central line in place for at least 24 hours. The median age was 32 months, and 97 (57%) of the patients were males. The CLABSI incidence rate was 3.9/1000 central venous catheter-days. The incidence among hospitals varied from 1.6 to 6.6. The overall mortality rate was 11.1%, and the CLABSI and non-CLABSI mortality rates were 12.9% and 10.7%, respectively. In multivariate analysis, independent risk factors for CLABSI were a longer duration of central venous catheter use (OR: 1.07; 95%CI 1.00 - 1.14; p = 0.019) and the use of more than one central venous catheter at once (OR: 2.59; 95%CI 1.17 - 5.73; p = 0.048).

Conclusion

A longer duration of central venous catheter use and the use of more than one central venous catheter at once were the main risk factors for CLABSI in pediatric intensive care units.

Low bone mass density is associated with hemolysis in Brazilian patients with sickle cell disease

OBJECTIVES

To determine whether kidney disease and hemolysis are associated with bone mass density in a population of adult Brazilian patients with sickle cell disease.

INTRODUCTION

Bone involvement is a frequent clinical manifestation of sickle cell disease, and it has multiple causes; however, there are few consistent clinical associations between bone involvement and sickle cell disease.

METHODS

Patients over 20 years of age with sickle cell disease who were regularly followed at the Hematology and Hemotherapy Center of Campinas, Brazil, were sorted into three groups, including those with normal bone mass density, those with osteopenia, and those with osteoporosis, according to the World Health Organization criteria. The clinical data of the patients were compared using statistical analyses.

RESULTS

In total, 65 patients were included in this study: 12 (18.5%) with normal bone mass density, 37 (57%) with osteopenia and 16 (24.5%) with osteoporosis. Overall, 53 patients (81.5%) had bone mass densities below normal standards. Osteopenia and osteoporosis patients had increased lactate dehydrogenase levels and reticulocyte counts compared to patients with normal bone mass density (p<0.05). Osteoporosis patients also had decreased hemoglobin levels (p<0.05). Hemolysis was significantly increased in patients with osteoporosis compared with patients with osteopenia, as indicated by increased lactate dehydrogenase levels and reticulocyte counts as well as decreased hemoglobin levels. Osteoporosis patients were older, with lower glomerular filtration rates than patients with osteopenia. There was no significant difference between the groups with regard to gender, body mass index, serum creatinine levels, estimated creatinine clearance, or microalbuminuria.

CONCLUSION

A high prevalence of reduced bone mass density that was associated with hemolysis was found in this population, as indicated by the high lactate dehydrogenase levels, increased reticulocyte counts and low hemoglobin levels.

Diacylglycerol kinase-alpha phosphorylation by Src on Y335 is required for activation, membrane recruitment and Hgf-induced cell motility

Diacylglycerol (DAG) kinases (Dgk), which phosphorylate DAG to generate phosphatidic acid, act as either positive or negative key regulators of cell signaling. We previously showed that Src mediates growth factors-induced activation of Dgk-alpha, whose activity is required for cell motility, proliferation and angiogenesis. Here, we demonstrate that both hepatocytes growth factor (HGF) stimulation and v-Src transformation induce tyrosine phosphorylation of Dgk-alpha on Y335, through a mechanism requiring its proline-rich C-terminal sequence. Moreover, we show that both proline-rich sequence and phosphorylation of Y335 of Dgk-alpha mediate: (i) its enzymatic activation, (ii) its ability to interact respectively with SH3 and SH2 domains of Src, (iii) its recruitment to the membrane. In addition, we show that phosphorylation of Dgk-alpha on Y335 is required for HGF-induced motility, while its constitutive recruitment at the membrane by myristylation is sufficient to trigger spontaneous motility in absence of HGF. Providing the first evidence that tyrosine phosphorylation of Dgk-alpha is required for growth-factors-induced activation and membrane recruitment, these findings underscore its relevance as a rheostat, whose activation is a threshold to elicit growth factors-induced migratory signaling.

Hexarelin protects H9c2 cardiomyocytes from doxorubicin-induced cell death

Growth hormone secretagogues (GHSs) are synthetic peptidyl and nonpeptidyl molecules that possess strong growth hormone-releasing activity acting on specific pituitary and hypothalamic receptor subtypes. Differently from nonpeptidyl GHSs, peptidyl molecules such as hexarelin, a hexapeptide, possess specific high-affinity binding sites in animal and human heart and, after prolonged treatment, protect rats in vivo from ischemia-induced myocardial damage. To verify the hypothesis that peptidyl GHSs protect heart cells from cell death, we have investigated the cellular effects of hexarelin on H9c2 cardiomyocytes, a fetal cardiomyocyte-derived cell line, and on Hend, an endothelial cell line derived from transformed murine heart endothelium. We show that (i)H9c2 cardiomyocytes show specific binding for 125I-Tyr-Ala-hexarelin, which is inhibited by peptidyl GHSs such as Tyr-Ala-hexarelin and hexarelin but not by the nonpeptidyl GHS MK-0677, (ii) hexarelin promotes survival of H9c2 cardiomyocytes induced to die by doxorubicin, and (iii) that hexarelin inhibits apoptosis, as measured by DNA fragmentation, induced in both H9c2 myocytes and endothelial cells. In conclusion, our findings show that peptidyl GHSs such as hexarelin act as survival factors for cardiomyocytes and endothelium-derived cells in culture. These findings suggest that the inhibitory activity of hexarelin on cardiomyocytes and endothelial cell death could explain, at least partially, its cardioprotective effect against ischemia recorded in rats in vivo.

Neonatal and adult human heart tissues from normal subjects and patients with ischemic, dilated or hypertrophic cardiomyopathy express insulin-like growth factor binding protein-3 (IGFBP-3)

In the human fetus IGFBP-3 mRNA expression is most abundant in the skin, muscle and heart but circulating IGFBP-3 levels show age-related variations. In human heart tissues from controls and patients with either ischemic, dilated or hypertrophic cardiomyopathy (no.: 20, age-range from fetuses to elderly subjects) we determined the expression of cardiac IGFBP-3 mRNA by reverse transcriptase polymerase chain reaction (RT-PCR) and the protein by Western blotting. The same parameters were also determined in human livers. We detected IGFBP-3 mRNA in neonatal and adult as well as in fetal human heart tissues in both ventricles. Western blotting revealed the presence of IGFBP-3 in all the examined cardiac tissues. IGFBP-3 appeared to be more abundant in the heart than in the liver and in the failing hearts from patients with ischemic heart disease than in those with hypertrophic cardiomyopathy. Thus both normal and pathological human heart tissues express IGFBP-3 across lifespan and IGFBP-3 could play IGF-dependent and/or -independent actions at the myocardial level.

Src-mediated activation of alpha-diacylglycerol kinase is required for hepatocyte growth factor-induced cell motility

Diacylglycerol kinases are involved in cell signaling, either as regulators of diacylglycerol levels or as intracellular signal-generating enzymes. However, neither their role in signal transduction nor their biochemical regulation has been elucidated. Hepatocyte growth factor (HGF), upon binding to its tyrosine kinase receptor, activates multiple signaling pathways stimulating cell motility, scattering, proliferation and branching morphogenesis. Herein we demonstrate that: (i) the enzymatic activity of alpha-diacylglycerol kinase (alphaDgk) is stimulated by HGF in epithelial, endothelial and alphaDgk-transfected COS cells; (ii) cellular expression of an alphaDgk kinase-defective mutant inhibits activation of endogenous alphaDgk acting as dominant negative; (iii) specific inhibition of alphaDgk prevents HGF-induced cell movement of endothelial cells; (iv) HGF induces the association of alphaDgk in a complex with Src, whose tyrosine kinase activity is required for alphaDgk activation by HGF; (v) Src wild type stimulates alphaDgk activity in vitro; and (vi) alphaDgk can be tyrosine phosphorylated in intact cells.