Interleukin-6 plasma level increases with age in an Italian elderly population ("The Treviso Longeva"-Trelong-study) with a sex-specific contribution of rs1800795 polymorphism

The companion dog as a model for inflammaging: a cross-sectional pilot study

Inflammaging, the chronic, progressive proinflammatory state associated with aging, has been associated with multiple negative health outcomes in humans. The pathophysiology of inflammaging is complex; however, it is often characterized by high serum concentrations of inflammatory mediators such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and C-reactive protein (CRP). Few studies have evaluated the effects of age on inflammatory cytokines in companion dogs, and most of these studies included dogs of a single breed. In this cross-sectional study, we measured multiple circulating inflammatory markers and hematological parameters in banked serum samples from 47 healthy companion dogs of various breeds enrolled in the Dog Aging Project. Using univariate linear models, we investigated the association of each of these markers with age, sex, body weight, and body condition score (BCS), a measure of obesity in the dog. Serum IL-6, IL-8, and TNF-α concentrations were all positively associated with age. Lymphocyte count was negatively associated with age. Platelet count had a negative association with body weight. IL-2, albumin, cholesterol, triglyceride, bilirubin, S100A12, and NMH concentrations were not associated with age, weight, BCS, or sex after adjustment for multiple comparisons. Our findings replicate previous findings in humans, including increases in IL-6 and TNF-α with age, giving more evidence to the strength of the companion dog as a model for human aging.

The role of longevity-related genetic variant interactions as predictors of survival after 85 years of age

Genome-wide association studies and candidate gene studies have identified several genetic variants that might play a role in achieving longevity. This study investigates interactions between pairs of those single nucleotide polymorphisms (SNPs) and their effect on survival above the age of 85 in a sample of 327 Croatian individuals. Although none of the SNPs individually showed a significant effect on survival in this sample, 14 of the 359 interactions tested (between SNPs not in LD) reached the level of nominal significance (p<0.05), showing a potential effect on late-life survival. Notably, SH2B3 rs3184504 interacted with different SNPs near TERC, TP53 rs1042522 with different SNPs located near the CDKN2B gene, and CDKN2B rs1333049 with different SNPs in FOXO3, as well as with LINC02227 rs2149954. The other interaction pairs with a possible effect on survival were FOXO3 rs2802292 and ERCC2 rs50871, IL6 rs1800795 and GHRHR rs2267723, LINC02227 rs2149954 and PARK7 rs225119, as well as PARK7 rs225119 and PTPN1 rs6067484. These interactions remained significant when tested together with a set of health-related variables that also had a significant effect on survival above 85 years. In conclusion, our results confirm the central role of genetic regulation of insulin signalling and cell cycle control in longevity.

Dynamic model assuming mutually inhibitory biomarkers of frailty suggests bistability with contrasting mobility phenotypes

Bistability is a fundamental biological phenomenon associated with "switch-like" behavior reflecting the capacity of a system to exist in either of two stable states. It plays a role in gene regulation, cell fate switch, signal transduction and cell oscillation, with relevance for cognition, hearing, vision, sleep, gait and voiding. Here we consider a potential role for bistability in the existence of specific frailty states or phenotypes as part of disablement pathways. We use mathematical modeling with two frailty biomarkers (insulin growth factor-1, IGF-1 and interleukin-6, IL-6), which mutually inhibit each other. In our model, we demonstrate that small variations around critical IGF-1 or IL-6 blood levels lead to strikingly different mobility outcomes. We employ deterministic modeling of mobility outcomes, calculating the average trends in population health. Our model predicts the bistability of clinical outcomes: the deterministically-computed likelihood of an individual remaining mobile, becoming less mobile, or dying over time either increases to almost 100% or decreases to almost zero. Contrary to statistical models that attempt to estimate the likelihood of final outcomes based on probabilities and correlations, our model predicts functional outcomes over time based on specific hypothesized molecular mechanisms. Instead of estimating probabilities based on stochastic distributions and arbitrary priors, we deterministically simulate model outcomes over a wide range of physiological parameter values within experimentally derived boundaries. Our study is "a proof of principle" as it is based on a major assumption about mutual inhibition of pathways that is oversimplified. However, by making such an assumption, interesting effects can be described qualitatively. As our understanding of molecular mechanisms involved in aging deepens, we believe that such modeling will not only lead to more accurate predictions, but also help move the field from using mostly studies of associations to mechanistically guided approaches.

Paraoxonase 1 Activity is Associated with Interleukin-6 Levels in Type 2 Diabetes: Effects of Age and Gender

Background

A further understanding of the mechanisms linking inflammation to T2D and related complications can help prevent or control this silent but dangerous disease. This study was conducted to determine the association between paraoxonase 1 (PON1) activity and interleukin-6 (IL-6) in type 2 diabetes (T2D). Furthermore, we have evaluated the role of age and gender in the relationship between the PON1 activity and IL-6.

Methods

A total of 105 people with T2D were enrolled in this study. IL-6 levels were determined using ELISA. For the PON1 activity assay, the hydrolysis rate of the substrate phenylacetate was spectrophotometrically assayed in serum at 270 nm. The determined velocities were the initial velocities of substrate hydrolysis.

Results

PON1 activity was negatively correlated with IL-6 in total data (r = -0.34, P = 0.001). In both groups with age ≥50 and <50 years, PON1 activity was negatively correlated with IL-6, but the correlation was significant in patients aged 50 years and above (r = -0.358, P = 0.005) compared with patients with age <50 years. In both women and men, PON1 activity was negatively correlated with IL-6, but the correlation was significant in women (r = -0.318, P = 0.006) in comparison with men.

Conclusions

Inverse association between PON1 activity and IL-6 in T2D may represent the oxidative-inflammatory interaction in this disease. Our findings highlight that at older ages and in women, the associations between lower PON1 activity and higher IL-6 concentrations are more evident, and this should be considered in patients with T2D.

Association of Single-Nucleotide Polymorphisms in Interleukin Genes with Microbial Keratitis in a South Indian Population

BACKGROUND

To examine the relationship between single-nucleotide polymorphisms (SNPs) in interleukin (IL) genes and keratitis and its clinical manifestations.

METHODS

SNPs in IL1B, IL6, CXCL8, IL10, and IL12B were analysed. Differences in frequencies of alleles, genotypes and haplotypes between cases and controls as well as associations between SNPs and clinical variables were calculated by χ2 tests with odds ratios.

RESULTS

The minor homologous genotype in IL1B rs16944 (p = 0.036; odds ratio (OR) = 2.063, 95% confidence interval (CI): 1.048-4.061) and CXCL8 rs4073 (p = 0.041; OR = 0.463, 95% CI: 0.224-0.956) and the heterologous genotypes in IL6 rs1800795 (p = 0.046; OR = 0.563, 95% CI: 0.326-0.972) and IL12B rs2569254 (p = 0.0446; OR = 0.557, 95% CI: 0.314-0.989) or rs730691 (p = 0.0051; OR = 0.451, 95% CI: 0.260-0.784) were associated with keratitis. The minor genotype of rs16944 was associated with severe infection (p = 0.046). The heterologous genotype in rs2569254 was associated with hospital admission, photophobia, and mode of contact lens wear (p ≤ 0.041). The heterologous genotype in rs730691 was associated with blurred vision, discharge, anterior chamber reaction, and mode of wear (p ≤ 0.047).

CONCLUSIONS

This study demonstrates that SNPs in IL1B and CXCL8 are associated with risk of developing keratitis. The study also found relationships between SNPs and clinical measures of keratitis. The potential for ethnic differences in frequency of SNPs and their association with keratitis should be followed up using different populations.

The Effect of protease inhibitors-based antiretroviral therapy on serum/plasma interleukin-6 levels among PLHIV: a systematic review and meta-analysis

INTRODUCTION

Recommended treatment regimen for HIV infection includes protease inhibitors/ritonavir (PIs/r) combined with two nucleoside reverse transcriptase inhibitors (2NRTIs), that enable to achieve and maintain viral suppression, restore and preserve immune function. However, there were inconsistent findings on the levels of interleukin-6 levels (IL-6).

METHODOLOGY

Systematic review and meta-analysis were performed to quantify the pooled effects of PIs/r-based ART on serum/plasma IL-6 levels in PLHIV. PubMed, Web of Science, and Embase were searched from the earliest record to November 4, 2020. Data analysis was conducted on Stata version 16 and Review Manager 5.3. A random-effect model was used to compute a pooled effect size and weighted mean difference (WMD) was considered the summary effect size. Heterogeneity between studies was estimated by Cochrane's Q test (chi-square test) and I-square statistic and subgroup analysis were performed to explore the source of heterogeneity.

RESULT

Initial search identified 3098 records and five studies (seven trials) met inclusion criteria. The pooled mean difference in serum/plasma IL-6 levels from baseline to follow-up was 0.534 pg/ml (95% CI: -0.012, 1.08, P=0.05, I² =76.4%). In subgroup analysis, there was a significant association between increased serum/plasma IL-6 levels, and age group ≥35 years old, baseline CD4⁺ counts <350 cell/mm³ , and mean viral load ≥ 4.5 log10 copies/ml.

CONCLUSION

We found that serum/plasma IL-6 levels increased after combined anti-retroviral therapy (cART) among treatment-naïve individuals who initiated a successful combination of PIs/r with 2NRTIs. This result also highlights the need to monitor serum/plasma IL-6 levels during antiviral therapy, which may aid in the effective future treatment of systemic inflammation and related disorders following elevated IL-6 levels. This article is protected by copyright. All rights reserved.

Making sense of IL-6 signalling cues in pathophysiology

Unravelling the molecular mechanisms that account for functional pleiotropy is a major challenge for researchers in cytokine biology. Cytokine-receptor cross-reactivity and shared signalling pathways are considered primary drivers of cytokine pleiotropy. However, reports epitomized by studies of Jak-STAT cytokine signalling identify interesting biochemical and epigenetic determinants of transcription factor regulation that affect the delivery of signal-dependent cytokine responses. Here, a regulatory interplay between STAT transcription factors and their convergence to specific genomic enhancers support the fine-tuning of cytokine responses controlling host immunity, functional identity, and tissue homeostasis and repair. In this review, we provide an overview of the signalling networks that shape the way cells sense and interpret cytokine cues. With an emphasis on the biology of interleukin-6, we highlight the importance of these mechanisms to both physiological processes and pathophysiological outcomes.

Diagnostic performance of serum interleukin-6 in pediatric acute appendicitis: a systematic review

BACKGROUND

Despite the radiological and analytical advances of the last decades, there is still a significant rate of diagnostic error in pediatric acute appendicitis. In recent years, multiple biomarkers have emerged as potential diagnostic tools. This study aimed to examine the diagnostic performance of serum interleukin-6 in pediatric acute appendicitis.

METHODS

We conducted a systematic review of the literature that involved an extensive search in the main databases of medical bibliography (Medline, PubMed, Web of Science and SciELO). Two independent reviewers selected the relevant articles based on the previously defined inclusion and exclusion criteria. Methodological quality of the selected article was rated using the QUADAS2 index. Data extraction was performed by two independent reviewers.

RESULTS

The research in the medical bibliography databases resulted in 68 articles. We removed 26 duplicates. Among the remaining 42 articles, we excluded 33 following the inclusion and exclusion criteria. Of the final 9 studies included in this review, 8 provided measured serum interleukin-6 values, and all of them reported significant differences between groups, but inconsistent results regarding sensitivity and specificity.

CONCLUSIONS

The diagnostic performance of interleukine-6 alone for the diagnosis of acute appendicitis in children is limited. The sensitivity and specificity of interleukine-6 for the diagnosis of non-complicated acute appendicitis in the pediatric population are moderate but increased in complicated appendicitis. There seems to be a direct relationship between serum level of interleukin-6 and the hours of evolution of abdominal pain in children with acute appendicitis. The increasingly widespread use of non-operative management of acute appendicitis warrants further exploration of the classificatory potential of this marker between complicated and uncomplicated appendicitis. We consider that this may be an avenue of research to explore in the future.

Association of Genetic Variants in IL6 Gene (rs1800795) with the Concentration of Inflammatory Markers (IL-6, hs-CRP) and Superoxide Dismutase in the Blood of Patients with Acute Pancreatitis—Preliminary Findings

In the course of acute pancreatitis, interleukin-6 plays an important role as a mediator in the inflammatory response. The course of inflammatory disease is associated with intensive oxidative stress, which may activate transcription factors leading to gene-expression changes. Isoenzymes of superoxide dismutase are involved in the defense against free radicals. This study aimed to evaluate changes in IL-6 concentration and the concentration/activity of superoxide dismutase isoenzymes (SOD1, SOD2, and SOD3) in the blood of patients with acute pancreatitis (AP) in terms of rs1800795 polymorphism in the IL6 gene. In the smoking AP patients group with the GC and GG genotypes, the plasma SOD1 concentration was significantly higher (p = 0.0146 and p = 0.0250, respectively) than in patients with CC genotype for SNP rs1800795 in the IL6 gene. An increase in SOD1 concentration in erythrocytes of AP patients with GC genotypes was also demonstrated compared to the individuals from the group with GG genotype (p = 0.0408). Furthermore, a positive correlation between IL-6 and SOD1 concentrations in the plasma of AP patients with GC genotype for SNP rs1800795 was shown. These results indicate that SOD1 may play a protective role against oxidative damage induced by inflammation in the group of AP patients with GC genotype.

miR-21 and miR-146a: The microRNAs of inflammaging and age-related diseases

The first paper on "inflammaging" published in 2001 paved the way for a unifying theory on how and why aging turns out to be the main risk factor for the development of the most common age-related diseases (ARDs). The most exciting challenge on this topic was explaining how systemic inflammation steeps up with age and why it shows different rates among individuals of the same chronological age. The "epigenetic revolution" in the past twenty years conveyed that the assessment of the individual genetic make-up is not enough to depict the trajectories of age-related inflammation. Accordingly, others and we have been focusing on the role of non-coding RNA, i.e. microRNAs (miRNAs), in inflammaging. The results obtained in the latest 10 years underpinned the key role of a miRNA subset that we have called inflammamiRs, owing to their ability to master (NF-κB)-driven inflammatory pathways. In this review, we will focus on two inflammamiRs, i.e. miR-21-5p and miR-146a-5p, which target a variety of molecules belonging to the NF-κB/NLRP3 pathways. The interplay between miR-146a-5p and IL-6 in the context of aging and ARDs will also be highlighted. We will also provide the most relevant evidence suggesting that circulating inflammamiRs, along with IL-6, can measure the degree of inflammaging.

Prevalence and Influence of the -174 G/C Polymorphism in the Interleukin-6 Gene in Arboviruses Infections

Dengue virus and Chikungunya virus are arboviruses that affect thousands of people worldwide annually. The mechanisms involved in viral pathogenesis still need to be better understood. Single nucleotide polymorphisms (SNPs) in immune genes may be involved in the protection, susceptibility, and/or progression of these diseases. This study was performed to investigate the SNP -174 G/C in the interleukin-6 (IL-6) gene in patients with dengue or chikungunya from Northeastern Brazil. A total of 581 blood samples were analyzed, of which 244 were part of the negative control group, genomic DNA was extracted, and the SNP was genotyped using real-time polymerase chain reaction (PCR). The data obtained were used to conduct statistical analyses of the genotype and allele frequencies. We suggest that the G/C genotype and C allele of the SNP -174 G/C in the IL-6 gene are related to protection against dengue in the studied population. No significant differences were observed in chikungunya patients. This is the first study that assessed the association of the SNP -174 G/C in patients with chikungunya. We identified the presence of the C allele as a protective factor against dengue in the studied population.

Donor genetic variants in interleukin-6 and interleukin-6 receptor associate with biopsy-proven rejection following kidney transplantation

Rejection after kidney transplantation remains an important cause of allograft failure that markedly impacts morbidity. Cytokines are a major player in rejection, and we, therefore, explored the impact of interleukin-6 (IL6) and IL-6 receptor (IL6R) gene polymorphisms on the occurrence of rejection after renal transplantation. We performed an observational cohort study analyzing both donor and recipient DNA in 1271 renal transplant‐pairs from the University Medical Center Groningen in The Netherlands and associated single nucleotide polymorphisms (SNPs) with biopsy-proven rejection after kidney transplantation. The C-allele of the IL6R SNP (Asp358Ala; rs2228145 A > C, formerly rs8192284) in donor kidneys conferred a reduced risk of rejection following renal transplantation (HR 0.78 per C-allele; 95%-CI 0.67–0.90; P = 0.001). On the other hand, the C-allele of the IL6 SNP (at position-174 in the promoter; rs1800795 G > C) in donor kidneys was associated with an increased risk of rejection for male organ donors (HR per C-allele 1.31; 95%-CI 1.08–1.58; P = 0.0006), but not female organ donors (P = 0.33). In contrast, neither the IL6 nor IL6R SNP in the recipient showed an association with renal transplant rejection. In conclusion, donor IL6 and IL6R genotypes but not recipient genotypes represent an independent prognostic marker for biopsy-proven renal allograft rejection.

Analysis of the levels of inflammatory parameters in persons over the age of 90

Chronic inflammatory conditions resulting from elevated levels of circulating proinflammatory mediators are common in the elderly. The aim of the paper was to analyze the balance between proinflammatory and anti-inflammatory markers in longevous individuals. The study was conducted in persons aged >90 years old, residents of Poland living either at home or staying at residential care facilities. The study included 90 persons (69 women and 21 men) aged between 90 and 103 years. Persons with abnormal CRP presented with a statistical tendency toward higher fibrinogen and lower IL10 and IL-1α levels compared to patients in whom CRP level was within the normal range. IL-6 concentration predicted abnormality within CRP. Inflammation in persons above the age of 90 years old might be linked to abnormal fibrinogen and IL-6 levels.

Effects of One Year of Vitamin D and Marine Omega-3 Fatty Acid Supplementation on Biomarkers of Systemic Inflammation in Older US Adults

BACKGROUND

Observational studies suggest vitamin D and marine ω-3 fatty acid (n-3 FA) supplements are associated with lower systemic inflammation. However, past trials have been inconsistent.

METHODS

The randomized, double-blind, placebo-controlled VITamin D and OmegA-3 TriaL (VITAL) tested vitamin D (2000 IU/day) and/or n-3 FA (1 g/day) supplementation in a 2 × 2 factorial design among women ≥55 and men ≥50 years of age. We assessed changes in interleukin (IL)-6, tumor necrosis factor receptor 2 (TNFR2), and high-sensitivity C-reactive protein (hsCRP) concentrations from baseline to 1 year among participants randomized to vitamin D + n-3 FA (392), vitamin D (392), n-3 FA (392), or placebo only (385). Geometric means and percent changes were compared, adjusting for baseline factors.

RESULTS

Baseline characteristics were well balanced. In the active arms, 25-OH vitamin D rose 39% and n-3 FA rose 55% vs minimal change in placebo arms. Neither supplement reduced biomarkers at 1 year. Vitamin D resulted in 8.2% higher IL-6 (95% CI, 1.5%-15.3%; adjusted P = 0.02), but TNFR2 and hsCRP did not. Among 784 receiving vitamin D, hsCRP increased 35.7% (7.8%-70.9%) in those with low (<20 ng/mL) but not with higher baseline serum 25(OH) vitamin D [0.45% (-8.9% to 10.8%); P interaction = 0.02]. Among 777 randomized to n-3 FA, hsCRP declined [-10.5% (-20.4% to 0.8%)] in those with baseline low (<1.5 servings/week), but not with higher fish intake [6.4% (95% CI, -7.11% to 21.8%); P interaction = 0.06].

CONCLUSIONS

In this large sample from a population-based randomized controlled trial, neither vitamin D nor n-3 FA supplementation over 1 year decreased these biomarkers of inflammation.

CLINICALTRIALSGOV IDENTIFIER

NCT01169259; NCT01351805.

Review and meta-analysis of genetic polymorphisms associated with exceptional human longevity

BACKGROUND

Many factors contribute to exceptional longevity, with genetics playing a significant role. However, to date, genetic studies examining exceptional longevity have been inconclusive. This comprehensive review seeks to determine the genetic variants associated with exceptional longevity by undertaking meta-analyses.

METHODS

Meta-analyses of genetic polymorphisms previously associated with exceptional longevity (85+) were undertaken. For each variant, meta-analyses were performed if there were data from at least three independent studies available, including two unpublished additional cohorts.

RESULTS

Five polymorphisms, ACE rs4340, APOE ε2/3/4, FOXO3A rs2802292, KLOTHO KL-VS and IL6 rs1800795 were significantly associated with exceptional longevity, with the pooled effect sizes (odds ratios) ranging from 0.42 (APOE ε4) to 1.45 (FOXO3A males).

CONCLUSION

In general, the observed modest effect sizes of the significant variants suggest many genes of small influence play a role in exceptional longevity, which is consistent with results for other polygenic traits. Our results also suggest that genes related to cardiovascular health may be implicated in exceptional longevity. Future studies should examine the roles of gender and ethnicity and carefully consider study design, including the selection of appropriate controls.

Youthful Processing Speed in Older Adults: Genetic, Biological, and Behavioral Predictors of Cognitive Processing Speed Trajectories in Aging

Objective: To examine the impact of genetic, inflammatory, cardiovascular, lifestyle, and neuroanatomical factors on cognitive processing speed (CPS) change over time in functionally intact older adults.

Methods: This observational study conducted over two time points, included 120 community dwelling cognitively normal older adults between the ages of 60 and 80 from the University of California San Francisco Memory and Aging Center. Participants were followed with composite measures of CPS, calculated based on norms for 20–30 year-olds. Variables of interest were AD risk genes (APOE, CR1), markers of inflammation (interleukin 6) and cardiovascular health (BMI, LDL, HDL, mean arterial pressure, fasting insulin), self-reported physical activity, and corpus callosum (CC) volumes. The sample was divided into three groups: 17 “resilient-agers” with fast and stable processing speed; 56 “average-agers” with average and stable processing speed; and 47 “sub-agers” with average baseline speed who were slower at follow-up.

Results: Resilient-agers had larger baseline CC volumes than sub-agers (p < 0.05). Resilient-agers displayed lower levels of interleukin-6 (IL-6) and insulin (ps < 0.05) than sub-agers, and reported more physical activity than both average- and sub-agers (ps < 0.01). In a multinomial logistic regression, physical activity and IL-6 predicted average- and sub-ager groups. Resilient-agers displayed a higher frequency of APOE e4 and CR1 AA/AG alleles.

Conclusion: Robust and stable CPS is associated with larger baseline CC volumes, lower levels of inflammation and insulin, and greater self-reported physical activity. These findings highlight the relevance of neuroanatomical, biological, and lifestyle factors in the identification and prediction of heterogeneous cognitive aging change over time.

The Inflammatory Transcription Factors NFκB, STAT1 and STAT3 Drive Age-Associated Transcriptional Changes in the Human Kidney

Human kidney function declines with age, accompanied by stereotyped changes in gene expression and histopathology, but the mechanisms underlying these changes are largely unknown. To identify potential regulators of kidney aging, we compared age-associated transcriptional changes in the human kidney with genome-wide maps of transcription factor occupancy from ChIP-seq datasets in human cells. The strongest candidates were the inflammation-associated transcription factors NFκB, STAT1 and STAT3, the activities of which increase with age in epithelial compartments of the renal cortex. Stimulation of renal tubular epithelial cells with the inflammatory cytokines IL-6 (a STAT3 activator), IFNγ (a STAT1 activator), or TNFα (an NFκB activator) recapitulated age-associated gene expression changes. We show that common DNA variants in RELA and NFKB1, the two genes encoding subunits of the NFκB transcription factor, associate with kidney function and chronic kidney disease in gene association studies, providing the first evidence that genetic variation in NFκB contributes to renal aging phenotypes. Our results suggest that NFκB, STAT1 and STAT3 underlie transcriptional changes and chronic inflammation in the aging human kidney.

The structure and function of human kidneys deteriorate steadily with age, yet little is known about the underlying causes of kidney aging. In this work, we first used a genomics approach to identify candidate regulators of gene expression changes in the aging human kidney and identified inflammation-related transcription factors NFκB, STAT1 and STAT3 as the top candidate regulators. We found that kidney aging is associated with activation of NFκB, STAT1 and STAT3 in the renal parenchyma, and that the gene expression signatures evoked by activation of these transcription factors in human renal epithelial cells mimics age-associated gene expression changes in the kidney. Furthermore, we identified specific genetic variants in the NFκB transcription factor genes RELA and NFKB1 that associate with renal function and chronic kidney disease in humans, implicating NFκB as a potential contributor to the pathogenesis of chronic kidney disease and renal dysfunction in old age. Our findings suggest that activation of the inflammatory transcription factors STAT1, STAT3 and NFκB underlie transcriptional changes and reduced renal function in the elderly.

The SIRT1 promoter polymorphic site rs12778366 increases IL-6 related human mortality in the prospective study "Treviso Longeva (TRELONG)"

Studies on sirtuins (SIRT), a family of proteins with deacetylase activity, have provided convergent evidence of the key role of these enzymes in aging-linked physiological functions. The link between SIRT1 and longevity has emerged in model organism but few data are available in humans, in particular relying on longitudinal studies. Here, we assessed whether a genetic variant within SIRT1 gene promoter (rs12778366) was associated to human longevity. We analyzed 586 genomic DNA (gDNA) collected in the study "Treviso Longeva" (TRELONG), including elderly over 70 years of age from the municipality of Treviso, a town in the Northeast of Italy, with a 11-year follow-up. We genotyped SIRT1 rs12778366 by real-time polymerase chain reaction (RT-PCR) allelic discrimination assay. A cross-sectional analysis performed by comparing people over and under 85 years of age did not evidence association between rs12778366 and longevity. When we performed a longitudinal analysis considering mortality as dependent variable, we did not observe an association of rs12778366 with longevity in the whole population (corrected P-value = 0.33). However, when we stratified the TRELONG subjects according to circulating level of interleukin-6 (IL-6), a predictor of disability and mortality, we found that rs12778366 (TC+CC) carriers were at increased risk of mortality in comparison to the TT reference group (corrected P-value = 0.03, HR 1.47). Our data do not support a major role of rs12778366 in human longevity, but the stratified analysis on IL-6 suggests that this variant may be involved in the detrimental effect of high circulating IL-6 in the elderly.

Exceptional longevity and muscle and fitness related genotypes: a functional in vitro analysis and case-control association replication study with SNPs THRH rs7832552, IL6 rs1800795, and ACSL1 rs6552828

There are several gene variants that are candidates to influence functional capacity in long-lived individuals. As such, their potential association with exceptional longevity (EL, i.e., reaching 100+ years) deserves analysis. Among them are rs7832552 in the thyrotropin-releasing hormone receptor (TRHR) gene, rs1800795 in the interleukin-6 (IL6) gene and rs6552828 in the coenzyme A synthetase long-chain 1 (ACSL1) gene. To gain insight into their functionality (which is yet unknown), here we determined for the first time luciferase gene reporter activity at the muscle tissue level in rs7832552 and rs6552828. We then compared allele/genotype frequencies of the 3 abovementioned variants among centenarians [n = 138, age range 100–111 years (114 women)] and healthy controls [n = 334, 20–50 years (141 women)] of the same ethnic and geographic origin (Spain). We also studied healthy centenarians [n = 79, 100–104 years (40 women)] and controls [n = 316, 27–81 years (156 women)] from Italy, and centenarians [n = 742, 100–116 years (623 women)] and healthy controls [n = 499, 23–59 years (356 women)] from Japan. The THRH rs7832552 T-allele and ACSL1 rs6552828 A-allele up-regulated luciferase activity compared to the C and G-allele, respectively (P = 0.001). Yet we found no significant association of EL with rs7832552, rs1800795 or rs6552828 in any of the 3 cohorts. Further research is needed with larger cohorts of centenarians of different origin as well as with younger old people.

Interleukin-6, age, and corpus callosum integrity

The contribution of inflammation to deleterious aging outcomes is increasingly recognized; however, little is known about the complex relationship between interleukin-6 (IL-6) and brain structure, or how this association might change with increasing age. We examined the association between IL-6, white matter integrity, and cognition in 151 community dwelling older adults, and tested whether age moderated these associations. Blood levels of IL-6 and vascular risk (e.g., homocysteine), as well as health history information, were collected. Processing speed assessments were administered to assess cognitive functioning, and we employed tract-based spatial statistics to examine whole brain white matter and regions of interest. Given the association between inflammation, vascular risk, and corpus callosum (CC) integrity, fractional anisotropy (FA) of the genu, body, and splenium represented our primary dependent variables. Whole brain analysis revealed an inverse association between IL-6 and CC fractional anisotropy. Subsequent ROI linear regression and ridge regression analyses indicated that the magnitude of this effect increased with age; thus, older individuals with higher IL-6 levels displayed lower white matter integrity. Finally, higher IL-6 levels were related to worse processing speed; this association was moderated by age, and was not fully accounted for by CC volume. This study highlights that at older ages, the association between higher IL-6 levels and lower white matter integrity is more pronounced; furthermore, it underscores the important, albeit burgeoning role of inflammatory processes in cognitive aging trajectories.

Modulation of human longevity by SIRT3 single nucleotide polymorphisms in the prospective study "Treviso Longeva (TRELONG)"

Human sirtuins are seven proteins with deacetylase activity that are emerging as key modulators of basic physiological functions. Some evidence links SIRT3 to longevity in mammals. This study aimed to investigate whether variants within SIRT3 gene were associated to human longevity. We analyzed 549 genomic DNA collected during the prospective study "Treviso Longeva," including elderly over 70 years of age from the municipality of Treviso, a small city in the northeast of Italy. We genotyped SIRT3 rs3825075, rs4980329, and rs11555236 single nucleotide polymorphisms (SNPs) by real-time polymerase chain reaction allelic discrimination assay. A cross-sectional analysis performed by comparing people over and under 85 years of age did not evidence association among the SIRT3 SNPs and longevity. However, when we performed a longitudinal analysis considering mortality as a dependent variable, we observed an association of SIRT3 rs11555236 and rs4980329 with longevity in the whole population (p values corrected for potential confounders = 0.04 and 0.03, respectively). After stratification according to gender, the same SNPs were associated to female longevity only (p values corrected for potential confounders = 0.03 and 0.02, respectively). Finally, as rs11555236 was reported to be in linkage disequilibrium with a putative functional enhancer within the SIRT3 gene, we assessed whether rs11555236 genotypes correlated with a different level of SIRT3 protein in peripheral blood mononuclear cells. We found an increased level of SIRT3 in subjects homozygous for the (T) allele. We suggest that SIRT3 genetic variability might be relevant for the modulation of human longevity in the Italian population.

Insulin-like growth factor 1 receptor polymorphism rs2229765 and circulating interleukin-6 level affect male longevity in a population-based prospective study (Treviso Longeva--TRELONG)

Insulin-like growth factor 1 (IGF-1) signaling modulation has been associated with increased lifespan in model organisms, while high levels of circulating interleukin-6 (IL-6) are a marker of disability and mortality. In the prospective, population-based "Treviso Longeva"--TRELONG Study from Italy (n = 668, age range 70-105.5 years at baseline, followed for seven years) we investigated the effects of survival on the IGF-1 receptor (IGF-1R) gene polymorphism rs2229765, the IL-6 gene promoter polymorphism rs1800795, and plasma concentrations of IGF-1 and IL-6, alone or in combination. We found a sex-dependent effect for the IGF-1R rs2229765 polymorphism, as male carriers of the homozygous A/A genotype survived longer, while the IL-6 rs1800795 genotype did not influence overall or sex-specific longevity. Higher IL-6 levels were more detrimental for survival among males than females, while IGF-1 had no dose-response effect. These findings sustain the hypothesis that sex-specific longevity relies on detectable differences in genetic and biochemical parameters between males and females.

Features, causes and consequences of splanchnic sequestration of amino acid in old rats

Rationale

In elderly subjects, splanchnic extraction of amino acids (AA) increases during meals in a process known as splanchnic sequestration of amino acids (SSAA). This process potentially contributes to the age-related progressive decline in muscle mass via reduced peripheral availability of dietary AA. SSAA mechanisms are unknown but may involve an increased net utilization of ingested AA in the splanchnic area.

Objectives

Using stable isotope methodology in fed adult and old rats to provide insight into age-related SSAA using three hypotheses: 1) an increase in protein synthesis in the gut and/or the liver, 2) an increase in AA oxidation related to an increased ureagenesis, and 3) Kupffer cell (KC) activation consequently to age-related low-grade inflammation.

Findings

Splanchnic extraction of Leu (SPELeu) was doubled in old rats compared to adult rats and was not changed after KC inactivation. No age-related effects on gut and liver protein synthesis were observed, but urea synthesis was lower in old rats and negatively correlated to liver Arg utilization. Net whole-body protein synthesis and arterial AA levels were lower in old rats and correlated negatively with SPELeu.

Conclusion

SSAA is not the consequence of age-related alterations in ureagenesis, gut or liver protein synthesis or of KC activity. However, SSAA may be related to reduced net whole-body protein synthesis and consequently to the reduced lean body mass that occurs during aging.

Age- and gender-specific epistasis between ADA and TNF-α influences human life-expectancy

Aging is a complex phenotype with multiple determinants but a strong genetic component significantly impacts on survival to extreme ages. The dysregulation of immune responses occurring with increasing age is believed to contribute to human morbidity and mortality. Conversely, some genetic determinants of successful aging might reside in those polymorphisms for the immune system genes regulating immune responses. Here we examined the main effects of single loci and multi-locus interactions to test the hypothesis that the adenosine deaminase (ADA) and tumor necrosis factor alpha (TNF-α) genes may influence human life-expectancy. ADA (22G>A, rs73598374) and TNF-α (-308G>A, rs1800629; -238G>A, rs361525) functional SNPs have been determined for 1071 unrelated healthy individuals from Central Italy (18-106 years old) divided into three gender-specific age classes defined according to demographic information and accounting for the different survivals between sexes: for men (women), the first class consists of individuals<66 years old (<73 years old), the second class of individuals 66-88 years old (73-91 years old), and the third class of individuals>88 years old (>91 years old). Single-locus analysis showed that only ADA 22G>A is significantly associated with human life-expectancy in males (comparison 1 (age class 2 vs. age class 1), O.R. 1.943, P=0.036; comparison 2 (age class 3 vs. age class 2), O.R. 0.320, P=0.0056). Age- and gender-specific patterns of epistasis between ADA and TNF-α were found using Generalized Multifactor Dimensionality Reduction (GMDR). In comparison 1, a significant two-loci interaction occurs in females between ADA 22G>A and TNF-α -238G>A (Sign Test P=0.011). In comparison 2, both two-loci and three-loci interaction are significant associated with increased life-expectancy over 88 years in males. In conclusion, we report that a combination of functional SNPs within ADA and TNF-α genes can influence life-expectancy in a gender-specific manner and that males and females follow different pathways to attain longevity.

An NFKB1 promoter insertion/deletion polymorphism influences risk and outcome in acute respiratory distress syndrome among Caucasians

Background

Nuclear factor-κB (NF-κB) is required for transcription of many pro-inflammatory genes and has been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS). We hypothesized that a known functional polymorphism in the promoter of the NFKB1 gene may affect susceptibility to and outcome from ARDS.

Methods

A case control study was conducted among a cohort of patients admitted to the intensive care unit (ICU) with risk factors for the development of ARDS. 379 patients with ARDS and 793 at-risk controls were studied. Patients were followed for 60 days with development of ARDS as a primary outcome; ARDS-related mortality and organ dysfunction were secondary outcomes.

Results

Patients homozygous for the 4 base pair deletion in the promoter of NFKB1 (del/del) did not have an increased odds ratio (OR) of developing ARDS in unadjusted analysis but were more likely to develop ARDS in the presence of a significant interaction between the del/del genotype and age (OR 5.21, 95% CI 1.35–20.0). In multivariate analysis, patients with ARDS and the del/del genotype also had increased 60 day mortality (HR 1.54, 95% CI 1.01–2.36) and more severe daily organ dysfunction (P<.001) when compared to ARDS patients with other genotypes.

Conclusion

The del/del genotype is associated with an age-dependent increase in odds of developing ARDS. Patients with the del/del genotype and ARDS also have increased hazard of 60 day mortality and more organ failure.