Serum anti-inflammatory and inflammatory markers have no causal impact on telomere length: a Mendelian randomization study

Study of association of leptin with leukocyte telomere length in a Chinese rural population

BACKGROUND

Previous studies have demonstrated the relationship between adipocyte factors, insulin resistance, and other indicators with telomere length. However, these studies did not consider the influence of changes in different indicators on telomere length over time. Therefore, the aim of this study is to elucidate the impact of changes in adipocyte factors, HOMA-IR, and other indicators on the dynamic variation of telomere length.

METHODS

The data were from a cohort study conducted in Ningxia, China. A total of 1624 subjects were analyzed. Adipokines and relative leukocyte telomere length (RLTL) were measured, and changes in Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), Homeostatic Model Assessment for β-Cell Function (HOMA-β), and Quantitative Insulin Sensitivity Check Index (QUICKI) were calculated. Generalized linear models evaluated associations between changes in adipokines and RLTL changes. Furthermore, univariate analyses examined the effects of changes in adipokines and insulin resistance indicators on ΔRLTL.

RESULTS

The research findings indicate that females generally have shorter telomeres compared to males. In comparison to the low-level group of Δleptin (LEP), the high-level group of ΔLEP shows a negative correlation with ΔRLTL (B=-1.32, 95% CI (-2.38, -0.27)). Even after multivariable adjustments, this relationship persists (B=-1.31, 95% CI (-2.24, -0.23)). Further analysis reveals that after adjusting for ΔHOMA-IR, ΔHOMA-β, and ΔQUICKI, the high-level group of ΔLEP still exhibits a significant negative correlation with ΔRLTL (B=-1.37, 95% CI (-2.43, -0.31)). However, the interaction effects between ΔHOMA-IR, ΔHOMA-β, ΔQUICKI, and ΔLEP do not affect ΔRLTL.

CONCLUSIONS

Elevated levels of leptin were significantly correlated with shortened telomere length. This suggests that increased leptin levels may impact overall individual health by affecting telomere length, underscoring the importance of measures to reduce leptin levels to mitigate the onset and progression of related diseases.

The causal associations of altered inflammatory proteins with sleep duration, insomnia and daytime sleepiness

STUDY OBJECTIVES

Growing evidence linked inflammation with sleep. This study aimed to evaluate the associations and causal effects of sleep traits including insomnia, excessive daytime sleepiness (EDS), and sleep duration (short: <7 h; normal: 7-9 h; long: ≥9 h), with levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukins.

METHODS

Standard procedures of quantitative analysis were applied to estimate the expression differences for each protein in compared groups. Then, a two-sample Mendelian randomization (MR) analysis was performed to explore their causal relationships with published genome-wide association study summary statistics. The inverse-variance weighted was used as the primary method, followed by several complementary approaches as sensitivity analyses.

RESULTS

A total of 44 publications with 51 879 participants were included in the quantitative analysis. Our results showed that the levels of CRP, interleukin-1β (IL-1β), IL-6, and TNF-α were higher from 0.36 to 0.58 (after standardization) in insomnia compared with controls, while there was no significant difference between participants with EDS and controls. Besides, there was a U/J-shaped expression of CRP and IL-6 with sleep durations. In MR analysis, the primary results demonstrated the causal effects of CRP on sleep duration (estimate: 0.017; 95% confidence intervals [CI], [0.003, 0.031]) and short sleep duration (estimate: -0.006; 95% CI, [-0.011, -0.001]). Also, IL-6 was found to be associated with long sleep duration (estimate: 0.006; 95% CI, [0.000, 0.013]). These results were consistent in sensitivity analyses.

CONCLUSIONS

There are high inflammatory profiles in insomnia and extremes of sleep duration. Meanwhile, elevated CRP and IL-6 have causal effects on longer sleep duration. Further studies can focus on related upstream and downstream mechanisms.

Association between Combination Antiretroviral Therapy and Telomere Length in People Living with Human Immunodeficiency Virus

Long-term exposure to combination antiretroviral therapy (cART) may be associated with accelerated ageing. Telomere length is considered to be reliable aging biomarker. The aim of this study was to compare patients' relative telomere length (RTL) between and within different cART classes and to estimate the impact of certain HIV-related variables on RTL. The study was conducted in 176 HIV-infected male patients receiving cART, with ≤50 copies HIV RNA/mL plasma. RTL was determined from mononuclear cells by quantitative polymerase chain reaction. Standard statistical tests and unsupervised machine learning were performed. The mean RTL was 2.50 ± 1.87. There was no difference (p = 0.761) in RTL between therapeutic groups: two nucleoside reverse transcriptase inhibitors as the backbone treatment, combined with either integrase inhibitor, protease inhibitor, or non-nucleoside reverse transcriptase inhibitor (NNRTI). Machine learning results suggested duration of HIV infection, CD4+ T-cell count, and cART, including NNRTI, as potentially significant variables impacting RTL. Kendall's correlation test excluded duration of HIV infection (p = 0.220) and CD4+ T-cell count (p = 0.536) as significant. The Mann-Whitney test confirmed that cART containing NNRTI impacted RTL (p = 0.018). This was the first study to show that patients using efavirenz within cART had significantly shorter telomeres than patients using nevirapine.

Association of leptin receptor gene Gln223Arg polymorphism with insulin resistance and hyperglycemia in patients with metabolic syndrome

Introduction

Worldwide, there has been an increase in the incidence of metabolic syndrome. The search for genetic markers of this syndrome is ongoing. The leptin receptor has recently received attention. One of the polymorphisms (Gln223Arg) is possibly associated with the development of obesity and insulin resistance. However, the results of studies on this polymorphism remain equivocal. Gln223Arg polymorphism has not been studied previously in the Kyrgyz population. Thus, we aimed to investigate the possible association of the Gln223Arg polymorphism of the leptin receptor gene with metabolic syndrome components in the Kyrgyz population.

Material and methods

237 Kyrgyz subjects, aged 35-70 years, were studied. For the analysis anthropometric data, glucose, insulin, lipid spectrum, leptin were obtained. The genotype of the Gln223Arg leptin polymorphism was evaluated using TaqMan real-time PCR.

Results

The distribution of genotypes was as follows: Gln223Gln 46.4%, Gln223Arg 40.1%, Arg223Arg 13.5%. In the study no association was found with abdominal obesity, arterial hypertension, hypertriglyceridemia or low-density cholesterol levels. Relationships of Gln223Arg and Arg223Arg genotypes with insulin resistance (p < 0.03) were found. Gln223Arg polymorphism was associated with a higher level of glycemia (5.54 vs. 5.39 mmol/l, p < 0.05) and insulinemia (8.3 vs. 7.1 µIU/ml, p < 0.05). Correlation analysis showed that carriers of the Arg223 allele demonstrated a higher risk of insulin resistance (odds ratio (OR) = 1.83, 95% CI: 1.03-3.24; p < 0.03) than carriers of the Gln223 allele.

Conclusions

Gln223Arg polymorphism of the leptin receptor gene may be a marker of predisposition to insulin resistance in the Kyrgyz population. Further studies are necessary to confirm these results in populations from other regions.

Coffee or tea: Anti-inflammatory properties in the context of atherosclerotic cardiovascular disease prevention

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of premature death worldwide. Inflammation and its biomarkers, like C-reactive protein (CRP), among the risk factors, such as hypertension, lipid disorders, and diabetes, may be also responsible for the residual cardiovascular disease (CVD) risk. Modern lipid-lowering treatment with statins, ezetimibe, PCSK9 inhibitors, or bempedoic acid does not fully protect against inflammation. The recommendations of the International Lipid Expert Panel (ILEP) indicate selected nutraceuticals with anti-inflammatory properties. Diet may have a significant impact on inflammation. Especially interesting in the context of inflammation is the consumption of coffee and tea. These drinks in many observational studies significantly reduced cardiovascular risk and mortality. The question is whether the anti-inflammatory effects of these drinks contribute significantly to the observed clinical effects. Thus, in this narrative review, we primarily discuss the anti-inflammatory properties of consuming tea and coffee. Based on a comprehensive analysis of the studies and their meta-analyses, inconsistent results were obtained, which makes it impossible to conclusively state how clinically significant the potential anti-inflammatory properties of black and green tea and coffee are. A number of confounding factors can cause the inconsistency of the available results. Consumption of tea and coffee appears to increase adiponectin concentrations, decrease reactive oxygen species, decrease low density lipoprotein (LDL) cholesterol concentrations (effect of green tea, etc.). Despite the still uncertain anti-inflammatory effect of tea and coffee, we recommend their consumption as a part of the healthy diet.

Association Between Telomere Length and Cardiovascular Risk: Pharmacological Treatments Affecting Telomeres and Telomerase Activity

Telomeres represent the ends of chromosomes, and they are composed of an extensive number of - TTAGGG nucleotide sequence repeats in humans. Telomeres prevent chromosome degradation, participate in stabilization, and regulate the DNA repair system. Inflammation and oxidative stress have been identified as important processes causing cardiovascular disease and accelerating telomere shortening rate. This review investigates the link between telomere length and pathological vascular conditions from experimental and human studies. Also, we discuss pharmacological treatments affecting telomeres and telomerase activity.

Leukocyte Telomere Length as a Molecular Biomarker of Coronary Heart Disease

Background. This work is a review of preclinical and clinical studies of the role of telomeres and telomerase in the development and progression of coronary heart disease (CHD). Materials and methods. A search for full-text publications (articles, reviews, meta-analyses, Cochrane reviews, and clinical cases) in English and Russian was carried out in the databases PubMed, Oxford University Press, Scopus, Web of Science, Springer, and E-library electronic library using keywords and their combinations. The search depth is 11 years (2010–2021). Results. The review suggests that the relative leukocyte telomere length (LTL) is associated with the development of socially significant and widespread cardiovascular diseases such as CHD and essential hypertension. At the same time, the interests of researchers are mainly focused on the study of the relative LTL in CHD. Conclusions. Despite the scientific and clinical significance of the analyzed studies of the relative length of human LTL as a biological marker of cardiovascular diseases, their implementation in real clinical practice is difficult due to differences in the design and methodology of the analyzed studies, as well as differences in the samples by gender, age, race, and ethnicity. The authors believe that clinical studies of the role of the relative length of leukocyte telomeres in adult patients with coronary heart disease are the most promising and require large multicenter studies with a unified design and methodology.

The role of inflammation and the possibilities of inflammation reduction to prevent cardiovascular events

Chronic systemic inflammation is a risk factor for cardiovascular (CV) disease (CVD). Whether this relationship extends to subclinical inflammation, quantified by values of circulating markers associated with inflammation in the high range of the normal interval, remains debatable. This narrative review evaluates evidence exploring this relationship. A review of pharmacological and non-pharmacological interventions, including diet and lifestyle strategies, supplements, nutraceuticals, and other natural substances aimed at reducing inflammation was also conducted, since few reviews have synthesized this literature. PubMed and EMBASE were used to search the literature and several well-studied triggers of inflammation [oxidized LDL, Lp(a), as well as C-reactive protein (CRP)/high-sensitivity CRP (hs-CRP)] were included to increase sensitivity and address the lack of existing reviews summarizing their influence in the context of inflammation. All resulting references were assessed. Overall, there is good data supporting associations between circulating hs-CRP and CV outcomes. However, the same was not seen in studies evaluating triggers of inflammation, such as oxidized LDL or Lp(a). There is also insufficient evidence showing treatments to target inflammation and lead to reductions in hs-CRP result in improvements in CV outcomes, particularly in those with normal baseline levels of hs-CRP. Regarding pharmacological interventions, statins, bempedoic acid, and apabetalone significantly reduce circulating hs-CRP, unlike PCSK-9 inhibitors. A variety of natural substances and vitamins were also evaluated and none reduced hs-CRP. Regarding non-pharmacological interventions, weight loss was strongly associated with reductions in circulating hs-CRP, whereas various dietary interventions and exercise regimens were not, unless accompanied by weight loss.

Associations between serum urate and telomere length and inflammation markers: Evidence from UK Biobank cohort

Objective

Hyperuricemia and gout have become gradually more common. The effect of serum urate on organism aging and systematic inflammation is not determined. This study aims to evaluate whether serum urate is causally associated with cellular aging markers and serum inflammation markers.

Methods

A Mendelian randomization study was performed on summary-level data from the largest published genome-wide association studies. Single nucleotide polymorphisms with a genome-wide significance level were selected as instrumental variables for leukocyte telomere length (LTL), and serum soluble makers of inflammation (CRP, IL-6, TNF-α, and IGF-1). Standard inverse variance weighted (IVW) method was used as the primary statistical method. The weighted median, MR-Egger regression, and MR-PRESSO methods were used for sensitivity analysis.

Results

An inverse causal association of genetically predicted serum urate levels and LTL was found using IVW method (OR: 0.96, 95%CI 0.95, 0.97; β=-0.040; SE=0.0072; P=4.37×10^-8). The association was also supported by MR results using MR-Egger method and weighted median method. The MR-PRESSO analysis and leave-one-out sensitivity analysis supported the robustness of the combined results. In terms of other aging-related serum biomarkers, there was no evidence supporting a causal effect of serum urate on CRP, IL-6, TNF-α, or IGF-1 levels.

Conclusions

Serum urate levels are negatively associated with telomere length but are not associated with serum soluble indicators of inflammation. Telomere length may be a critical marker that reflects urate-related organismal aging and may be a mechanism in the age-related pathologies and mortality caused by hyperuricemia.

The association between coffee and caffeine consumption and renal function: insight from individual-level data, Mendelian randomization, and meta-analysis

INTRODUCTION

The reported relationship between coffee intake and renal function is poorly understood. By applying two-sample Mendelian randomization (MR) and systematic review and meta-analysis we investigated the association of caffeine and coffee intake with prevalent CKD and markers of renal function.

MATERIAL AND METHODS

For the individual data analysis we analyzed the National Health and Nutrition Examination Surveys (NHANES) data on renal function markers and caffeine intake. MR was implemented by using summary-level data from the largest ever genome-wide association studies (GWAS) conducted on coffee intake (N = 91,462) and kidney function (N = 133,413). The inverse variance weighted method (IVW), weighted median-based method, MR-Egger, MR-RAPS, and MR-PRESSO were applied. Random effects models and generic inverse variance methods were used to synthesize quantitative and pooled data for the meta-analysis, followed by a leave-one-out method for sensitivity analysis.

RESULTS

Finally, we included the data of 18,436 participants; 6.9% had prevalent CKD (based on eGFR). Caffeine intake for the general population was 131.1 ±1.1 mg. The percentage of participants with CKD, by caffeine quartile, was 16.6% in the first (lowest) quartile, 13.9% in the second, 12.2% in the third and 11.0% in the top quartile (p < 0.001). After adjustment, for increasing quartiles for caffeine consumption, mean urine albumin, albumin-creatinine ratio and estimated glomerular filtration rate (GFR) did not change significantly (p > 0.234). In fully adjusted logistic regression models, there was no significant difference in chances of CKD prevalence (p-trend = 0.745). In the same line, the results of MR showed no impact of coffee intake on CKD (IVW: β = -0.0191, SE = 0.069, p = 0.781) or on eGFR (overall = IVW: β = -0.0005, SE = 0.005, p = 0.926) either in diabetic (IVW: β = -0.006, SE = 0.009, p = 0.478) or non-diabetic patients (IVW: β = -6.772, SE = 0.006, p = 0.991). Results from the meta-analysis indicated that coffee consumption was not significantly associated with CKD (OR = 0.85, 95% CI: 0.71-1.02, p = 0.090, n = 6 studies, I ² = 0.32). These findings were robust in sensitivity analyses.

CONCLUSIONS

Implementing different strategies, we detected no significant association between coffee consumption and renal function or risk of CKD.