Uric acid has been linked with increased risk of chronic disease such as cardiovascular disease and this association has been attributed to a pro-inflammatory effect. Indeed, observational studies ...have shown that high uric acid is associated with high level of pro-inflammatory cytokines in the blood. However, whether high uric acid directly affects inflammation or rather represents a parallel defensive antioxidant mechanism in response to pathology that causes inflammation is unknown. To determine whether acute increase or decrease uric acid levels affects inflammation in healthy individuals, a randomized, placebo-controlled, double blind clinical study of uric acid or rasburicase with 20 healthy volunteers in each treatment-placebo group was conducted at the National Institute on Aging (NIA) Clinical Research Unit (CRU) at Harbor Hospital in Baltimore, MD. Change in inflammatory response was assessed by administering an oral lipid tolerance before and after the treatment of uric acid, rasburicase and placebo. Following uric acid administration, there was an accentuated increase in IL-6 during the oral lipid tolerance test (P<0.001). No significant differences were observed after lowering of uric acid with rasburicase. No side effects were reported throughout the trial. In health individuals, acute increase in uric acid results in an increased IL-6 response when challenged with lipid load. Such effect of amplification of inflammatory response may explain the higher risk of chronic diseases observed in subclinical hyperuricemia in observational studies.
ClinicalTrials.gov NCT01323335.
Rapid lifestyle and dietary changes have contributed to a rise in the global prevalence of metabolic syndrome (MetS), which presents a potential healthcare crisis, owing to its association with an ...increased burden of multiple cardiovascular and neurological diseases. Prior work has identified the role that genetic, lifestyle, and environmental factors can play in the prevalence of MetS. Metabolomics is an important tool to study alterations in biochemical pathways intrinsic to the pathophysiology of MetS. We undertook a metabolomic study of MetS in serum samples from two ethnically distinct, well-characterized cohorts-the Baltimore Longitudinal Study of Aging (BLSA) from the U.S. and the Tsuruoka Metabolomics Cohort Study (TMCS) from Japan. We used multivariate logistic regression to identify metabolites that were associated with MetS in both cohorts. Among the top 25 most significant (lowest
-value) metabolite associations with MetS in each cohort, we identified 18 metabolites that were shared between TMCS and BLSA, the majority of which were classified as amino acids. These associations implicate multiple biochemical pathways in MetS, including branched-chain amino acid metabolism, glutathione production, aromatic amino acid metabolism, gluconeogenesis, and the tricarboxylic acid cycle. Our results suggest that fundamental alterations in amino acid metabolism may be central features of MetS.
Frailty is a risk factor for poor health outcomes in older adults. The aim of this study was to identify plasma proteomic biomarkers of frailty in 752 men and women older than 65 years of age from ...the InCHIANTI study. One thousand three hundred one plasma proteins were measured using an aptamer-based assay. Associations of each protein with frailty status were assessed using logistic regression and four proteins creatine kinase M-type (CKM), B-type (CKB), C-X-C motif chemokine ligand 13 (CXCL13), and thrombospondin 2 (THBS2) were associated with frailty status. Two proteins, cyclin-dependent kinase 5 (CDK5/CDK5R1) and interleukin 1 alpha (IL1A), were associated with worsening of frailty status over time in volunteers free of frailty at baseline. Using partial least squares discriminant analysis (PLS-DA), data of 1301 proteins was able to discriminate between frail and non-frail with a 2% error rate. The proteins with greater discriminatory ability represented the inflammation, blood coagulation, and cell growth pathways. The utility of these proteins as biomarkers of frailty should be further explored.
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•The study provides molecular mechanisms of process of fatal hypothermia.•Mex3B could induce the activation of Socs3, followed by a change in caspase 3/7 activity in iliopsoas muscle ...cell.•rno-miR-203a-3p-Socs3-Casp3 or Mex3B-Socs3-Casp3 axis may be the part of the biological defense response to maintain homeostasis under extreme hypothermia.•rno-miR-203a-3p and Socs3 serve as novel supporting markers for cold exposure or the diagnosis of fatal hypothermia.
Forensic diagnosis of fatal hypothermia is considered difficult because no specific findings, such as molecular markers, have been identified. Therefore, determining the molecular mechanism in hypothermia and identifying novel molecular markers to assist in diagnosing fatal hypothermia are important. This study aimed to investigate microRNA (miRNA) and mRNA expression in iliopsoas muscle, which plays a role in homeostasis in mammals, to resolve the molecular mechanism in hypothermia. We generated rat models of mild, moderate, and severe hypothermia, then performed body temperature-dependent miRNA and mRNA expression analysis of the iliopsoas muscle using microarray and next-generation sequencing. Analysis showed that rno-miR-203a-3p expression was lower with decreasing body temperature, while Socs3 expression was significantly increased only by severe hypothermia. Luciferase reporter assays suggested that Socs3 expression is regulated by rno-miR-203a-3p. Socs3 and Mex3B small interfering RNA-mediated knockdown showed that suppressing Mex3B could induce the activation of Socs3, followed by a change in caspase 3/7 activity and adenosine triphosphate levels in iliopsoas muscle cells. These findings indicate that rno-miR-203a-3p and Mex3B are deactivated by a decrease in body temperature, whereby it contributes to suppressing apoptosis by accelerating Socs3. Accordingly, the rno-miR-203a-3p-Socs3-Casp3 or Mex3B-Socs3-Casp3 axis may be the part of the biological defense response to maintain homeostasis under extreme hypothermia.
Measures of cardiovascular health (CVH) assessed by a combination of behavioral and biological factors has shown protective associations with all-cause mortality. The mechanisms underlying these ...associations have not been fully elucidated. In this study, we characterized the plasma proteomics profile of CVH and tested whether specific proteins mediated the associations between CVH and all-cause mortality in participants of the InCHIANTI study. Of the 1301 proteins tested, 92 proteins were associated with CVH (22 positively, 70 negatively). Proteins most strongly associated with CVH included leptin (LEP), fatty acid binding protein 3 (FABP3), Angiopoietin-2 (ANGPT2), and growth-differential factor 15 (GDF15). Of the 92 CVH-associated proteins, 33 proteins significantly mediated the associations between CVH and all-cause mortality, with percent mediation ranging from 5 to 30%. The most significant mediating proteins were GDF15 and insulin-like growth factor 2 (IGFBP2). Proteins associated with better CVH were enriched for proteins that reflect the suppression of the complement coagulation and GH/IGF pathways.
The discovery of treatments to prevent or delay dementia and Alzheimer's disease is a priority. The gene APOE is associated with cognitive change and late‐onset Alzheimer's disease, and ...epidemiological studies have provided strong evidence that the e2 allele of APOE has a neuroprotective effect, it is associated with increased longevity and an extended healthy lifespan in centenarians. In this study, we correlated APOE genotype data of 222 participants of the New England Centenarian Study, including 75 centenarians, 82 centenarian offspring, and 65 controls, comprising 55 carriers of APOE e2, with aptamer‐based serum proteomics (SomaLogic technology) of 4,785 human proteins corresponding to 4,137 genes. We discovered a signature of 16 proteins that associated with different APOE genotypes and replicated the signature in three independent studies. We also show that the protein signature tracks with gene expression profiles in brains of late‐onset Alzheimer's disease versus healthy controls. Finally, we show that seven of these proteins correlate with cognitive function patterns in longitudinally collected data. This analysis in particular suggests that Baculoviral IAP repeat containing two (BIRC2) is a novel biomarker of neuroprotection that associates with the neuroprotective allele of APOE. Therefore, targeting APOE e2 molecularly may preserve cognitive function.
This work correlates a large set of serum proteins with carriers of APOE e2 allele from a study of human longevity that includes centenarians and their offspring. The analysis discovers a reproducible signature of 16 serum proteins in cis and trans with APOE alleles. Expression profiles of genes in the signature in brains distinguish late‐onset Alzheimer's disease (LOAD) patients from healthy controls. Some of these proteins correlate with patterns of cognitive function and could be new therapeutic targets of neuroprotection.
Omega6 (n6) polyunsaturated fatty acids (PUFAs) and their metabolites are involved in cell signaling, inflammation, clot formation, and other crucial biological processes. Genetic components, such as ...variants of fatty acid desaturase (FADS) genes, determine the composition of n6 PUFAs.
To elucidate undiscovered biological pathways that may influence n6 PUFA composition, we conducted genome-wide association studies and meta-analyses of associations of common genetic variants with 6 plasma n6 PUFAs in 8631 white adults (55% women) across 5 prospective studies. Plasma phospholipid or total plasma fatty acids were analyzed by similar gas chromatography techniques. The n6 fatty acids linoleic acid (LA), γ-linolenic acid (GLA), dihomo-GLA, arachidonic acid, and adrenic acid were expressed as percentage of total fatty acids. We performed linear regression with robust SEs to test for single-nucleotide polymorphism-fatty acid associations, with pooling using inverse-variance-weighted meta-analysis. Novel regions were identified on chromosome 10 associated with LA (rs10740118; P=8.1×10(-9); near NRBF2), on chromosome 16 with LA, GLA, dihomo-GLA, and arachidonic acid (rs16966952; P=1.2×10(-15), 5.0×10(-11), 7.6×10(-65), and 2.4×10(-10), respectively; NTAN1), and on chromosome 6 with adrenic acid after adjustment for arachidonic acid (rs3134950; P=2.1×10(-10); AGPAT1). We confirmed previous findings of the FADS cluster on chromosome 11 with LA and arachidonic acid, and further observed novel genome-wide significant association of this cluster with GLA, dihomo-GLA, and adrenic acid (P=2.3×10(-72), 2.6×10(-151), and 6.3×10(-140), respectively).
Our findings suggest that along with the FADS gene cluster, additional genes may influence n6 PUFA composition.
Transient Receptor Potential Ankyrin 1 (TRPA1), which is expressed in the airways, has causative and exacerbating roles in respiratory diseases. TRPA1 is known as a target of sick building ...syndrome-related air pollutants, such as formaldehyde. Thus, an in vitro TRPA1 activation assay would be useful for predicting the potential risk of air pollution. In this study, we used human TRPA1 (hTRPA1)- and mouse TRPA1 (mTRPA1)-expressing cell lines to measure TRPA1 activation by the emerging indoor air pollutants 2-ethyl-1-hexanol (2-EH), a mixture of 2,2,4-trimethyl-1,3-pentanediol 1- and 3-monoisobutyrate (Texanol), and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB). The results indicated that 2-EH activated both hTRPA1 and mTRPA1 in a concentration-dependent manner, whereas TXIB did not activate hTRPA1 or mTRPA1. Texanol also activated hTRPA1 in a concentration-dependent manner. In contrast, a bell-shaped concentration-dependent curve was observed for mouse TRPA1 activation by Texanol, indicating inhibitory effects at a higher concentration range, which was also reported for menthol, a typical TRPA1 modulator. To further elucidate the mechanism underlying the species difference in TRPA1 activation by Texanol, V875G and G878V mutations were introduced into hTRPA1 and mTRPA1, respectively, which were reported to be key mutations for the inhibitory effect of menthol. These mutations switched the inhibitory effects of Texanol; thus, hTRPA1/V875G, but not mTRPA1/G878V, was inhibited at higher concentrations of Texanol. These results indicate that Texanol shares an interaction site with menthol. Overall, these findings suggest that careful interpretation is necessary when extrapolating rodent TRPA1-dependent toxicological effects to humans, especially with respect to the risk assessment of indoor air pollutants.
The B vitamins are components of one-carbon metabolism (OCM) that contribute to DNA synthesis and methylation. Homocysteine, a by-product of OCM, has been associated with coronary heart disease, ...stroke and neurological disease. To investigate genetic factors that affect circulating vitamin B6, vitamin B12, folate and homocysteine, a genome-wide association analysis was conducted in the InCHIANTI (N = 1175), SardiNIA (N = 1115), and BLSA (N = 640) studies. The top loci were replicated in an independent sample of 687 participants in the Progetto Nutrizione study. Polymorphisms in the
ALPL gene (rs4654748, p = 8.30 × 10
−18) were associated with vitamin B6 and
FUT2 (rs6022662, p = 2.83 × 10
−20) with vitamin B12 serum levels. The association of
MTHFR, a gene consistently associated with homocysteine, was confirmed in this meta-analysis. The
ALPL gene likely influences the catabolism of vitamin B6 while
FUT2 interferes with absorption of vitamin B12. These findings highlight mechanisms that affect vitamin B6, vitamin B12 and homocysteine serum levels.
Levels of angiotensin-converting enzyme 2 (ACE2), the gateway for COVID-19 virus into the cells, have been implicated in worse COVID-19 outcomes associated with aging and cardiovascular disease ...(CVD). Data on age-associated differences in circulating ACE2 levels in humans and the role of CVD and medications is limited. We analyzed data from 967 participants of the InCHIANTI study, a community-dwelling cohort in the Chianti region, Italy. Relative abundance of ACE2 in plasma was assessed using a proteomics platform. CVD diagnoses, use of renin-angiotensin-aldosterone system (RAAS) antagonists: ACEi, ARBs, and aldosterone antagonists, were ascertained. Multiple linear analyses were performed to examine the independent association of ACE2 with age, CVD, and RAAS antagonist use. Age was independently associated with lower log (ACE2) in persons aged ≥ 55 years (STD
β
= − 0.12,
p
= 0.0002). ACEi treatment was also independently associated with significantly lower ACE2 levels, and ACE2 was inversely associated with weight, and positively associated with peripheral artery disease (PAD) status. There was a trend toward higher circulating ACE2 levels in hypertensive individuals, but it did not reach statistical significance. In a stratified analysis, the association between log (ACE2) and log (IL-6) was more evidenced in participants with PAD. Circulating ACE2 levels demonstrate curvilinear association with age, with older individuals beyond the sixth decade age having lower levels. ACEi was associated with greater circulating ACE2 levels. Interestingly, ACE2 was elevated in PAD and positively associated with inflammatory markers, suggesting compensatory upregulation in the setting of chronic inflammation. Further studies are needed to comprehensively characterize RAAS components with aging and disease, and assess its prognostic role in predicting COVID-19 outcomes.
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