Genetic variants within telomere-associated genes, leukocyte telomere length and the risk of acute coronary syndrome in Czech women

Telomere Length: A Cardiovascular Biomarker and a Novel Therapeutic Target

Coronary artery disease (CAD) is a multifactorial disease with a high prevalence, particularly in developing countries. Currently, the investigation of telomeres as a potential tool for the early detection of the atherosclerotic disease seems to be a promising method. Telomeres are repetitive DNA sequences located at the extremities of chromosomes that maintain genetic stability. Telomere length (TL) has been associated with several human disorders and diseases while its attrition rate varies significantly in the population. The rate of TL shortening ranges between 20 and 50 bp and is affected by factors such as the end-replication phenomenon, oxidative stress, and other DNA-damaging agents. In this review, we delve not only into the pathophysiology of TL shortening but also into its association with cardiovascular disease and the progression of atherosclerosis. We also provide current and future treatment options based on TL and telomerase function, trying to highlight the importance of these cutting-edge developments and their clinical relevance.

Posttransplant Complications and Genetic Loci Involved in Telomere Maintenance in Heart Transplant Patients

Reaching critically short telomeres induces cellular senescence and ultimately cell death. Cellular senescence contributes to the loss of tissue function. We aimed to determine the association between variants within genes involved in telomere length maintenance, posttransplant events, and aortic telomere length in heart transplant patients. DNA was isolated from paired aortic samples of 383 heart recipients (age 50.7 ± 11.9 years) and corresponding donors (age 38.7 ± 12.0 years). Variants within the TERC (rs12696304), TERF2IP (rs3784929 and rs8053257), and OBCF1 (rs4387287) genes were genotyped, and telomere length was measured using qPCR. We identified similar frequencies of genotypes in heart donors and recipients. Antibody-mediated rejection (AMR) was more common (p < 0.05) in carriers of at least one G allele within the TERF2IP locus (rs3784929). Chronic graft dysfunction (CGD) was associated with the TERC (rs12696304) GG donor genotype (p = 0.05). The genetic risk score did not determine posttransplant complication risk prediction. No associations between the analyzed polymorphisms and telomere length were detected in either donor or recipient DNA. In conclusion, possible associations between donor TERF2IP (rs3784929) and AMR and between TERC (rs12696304) and CGD were found. SNPs within the examined genes were not associated with telomere length in transplanted patients.

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.

Accelerated biological aging secondary to cardiometabolic risk factors is a predictor of cardiovascular mortality: a systematic review and meta-analysis

BACKGROUND

Chronological aging is one of the major risk factors of cardiovascular disease (CVD); however, the impact of biological aging on CVD and outcomes remain poorly understood. Herein, we evaluated the association between leukocyte telomere length (LTL), a marker of biological age, and cardiovascular (CV) outcomes.

METHODS

We searched PubMed, Embase, Ovid Medline, and Web of Science Core Collection for the studies on the association between LTL and myocardial infarction (MI), CV death, and/or CVD risk factors from inception to July 2020. Extracted data were pooled in a random-effects meta-analysis and summarized as risk ratio (RR) and corresponding 95% confidence interval (95% CI) per LTL tertiles.

RESULTS

A total of 32 studies (n=144,610 participants) were included. In a pooled analysis of MI and LTL in a multivariate-adjusted model, the shortest LTL was associated with a 39% higher risk of MI (RR: 1.39, 95% CI: 1.16-1.67, p<0.001). After adjusting for chronological age and traditional covariance, we demonstrated a 28% increased risk of CV death in the shortest tertile of LTL (RR: 1.28, 95% CI:1.05-1.56, p=0.01). Analysis of the studies investigating the association between CV risk factors and LTL (N=7) demonstrated that diabetes mellitus is associated with a 46% increased risk of LTL attrition (RR: 1.46, 95% CI 1.46-2.09, p=0.039).

CONCLUSION

This study demonstrates a strong association between LTL, a marker of biological aging, and the risk of MI and CV death. Cardiometabolic risk factors contribute to telomere attrition and therefore accelerates biological aging.

PROSPERO ID

CRD42018112579.

The influence of TERC, TERT and ACYP2 genes polymorphisms on plasma telomerase concentration, telomeres length and T2DM

Telomeres are duplex tandem repeats of DNA sequence 5'-TTAGGG-3' at chromosomal ends synthesized by telomerase enzyme (TE). Telomeres length (TL) shortening is associated with age and age-related disorders. Recently, we demonstrated marked leukocytes TL (LTL) shortening in T2DM. To set the relationship between the TE, LTL and T2DM, we analyzed samples from 212 Kuwaiti subjects, 112 patients withT2DM and 100 non-diabetic subjects. The plasma TE and fasting insulin were measured by ELISA, the LTL was estimated by qPCR and three SNPs of genes related to TL; TERC rs12696304 (C/G), TERT rs2736100 (C/A) and ACYP2 rs6713088 (C/G) were genotyped by rtPCR. Results revealed comparable TE levels and alleles/genotypes between the cases and controls with no influence of either on the LTL. Interestingly, although the plasma concentration of the TE was generally low, it was significantly influenced by the TERT and ACYP2 but not TERC polymorphisms. The CC genotype carriers of rs2736100 (C/A) had significantly higher plasma TE levels compared to CA and AA carriers, p 0.009 and p 0.047, respectively, and the A-allele was associated with low TE, p 0.018. Similarly, significantly higher TE levels were detected in CC carriers of ACYP2 rs6713088 (C/G) compared with GC carriers, p 0.002, and the G-allele was associated with low TE, p 0.009. Finally, the TERT and ACYP2 polymorphisms had an influence on blood glucose levels. In conclusion, the telomeres shortening in T2DM was not due to TE deficiency or gene polymorphisms, while the TE levels were significantly associated with the TERT and ACYP2 but not TERC polymorphisms.

The telomerase gene polymorphisms, but not telomere length, increase susceptibility to primary glomerulonephritis/end stage renal diseases in females

Background

Primary glomerulonephritis (GN) is the leading cause of chronic kidney disease (CKD) and frequently progresses into end stage renal diseases (ESRDs). Shorter leukocyte telomere length (LTL) has been implicated in the CKD susceptibility and diminished kidney function, however, it is unclear whether the variants in telomerase genes contribute to risk to GN/CKD/ESRD. Here we address this issue by determining their association with the genetic variants of rs12696304 at the telomerase RNA component (TERC) and rs2736100 at the telomerase reverse transcriptase (TERT) loci.

Methods

The study includes 769 patients (243 primary GN-derived CKD and 526 ESRD cases) and sex-/age-matched healthy controls. Genomic DNA was extracted from peripheral blood of both controls and patients. Genotyping of rs12696304 and rs2736100 variants was carried out using PCR-based assays. Leukocyte telomere length (LTL) was determined using quantitative PCR (qPCR).

Results

A significantly higher frequency of TERC rs12696304 G allele was observed in patients and associated with increased disease risk (C vs G: OR = 1.334, 95% CI 1.112–1.586, P = 0.001; CC + GC vs GG: OR = 1.334, 95% CI 1.122–1.586, P = 0.001). Further analyses showed that such significant differences were only present between female controls and patients (C vs G: OR = 1.483, 95% CI 1.140–1.929, P = 0.003; CC + GC vs CC: OR = 1.692, 95% CI 1.202–2.383, P = 0.003), but not males. There were no differences in rs2736100 variants between controls and patients, but female ESRD patients carried significantly higher C allele frequencies than did female controls (A vs C: OR = 1.306, 95% CI 1.005–1.698, P = 0.046; AA vs CC: OR = 1.781, 95% CI 1.033–3.070, P = 0.037). There was no difference in LTL between controls and patients.

Conclusions

Our results reveal that the TERC rs12696304 and TERT rs2736100 polymorphisms, but not LTL per se, contribute to GN/CDK/ESRD risk.

Association between aortic telomere length and cardiac post-transplant allograft function

BACKGROUND

In patients having undergone orthotopic heart transplantation, a number of complications exist that are known to be connected to both telomerase activity and telomere length. The aim of this study was to determine how telomere length in aortic DNA correlates with the subsequent post-transplantation development of the patients.

MATERIALS AND METHODS

Between 2005 and 2015, we collected aortic samples from 376 heart recipients (age 50.8 ± 11.8 years) and 383 donors (age 38.6 ± 12.2 years). Relative telomere length in aortic tissue DNA was determined using quantitative PCR.

RESULTS

Shorter telomere length was detected in heart allograft recipients compared to donors (P < 0.0001). Patients suffering acute cellular rejection had significantly shorter telomere length (P < 0.01) than patients without rejection. Shorter telomere length was observed in patients with implanted mechanical circulatory support before heart transplantation (P < 0.03), as well as in subjects with cardiac allograft vasculopathy (P < 0.05). Overall survival time after heart transplantation was associated with shorter donor telomeres (P < 0.004).

CONCLUSIONS

Telomere length differed between donors and recipients independent of the sex and age of the patients. Our findings suggest a potential new linkage between the aortic telomere length of recipients and post-heart transplant complications. Further studies focusing on epigenetic modifications and gene regulation involved in telomere maintenance in transplanted patients should verify our results.

Telomerase RNA Component Genetic Variants Interact With the Mediterranean Diet Modifying the Inflammatory Status and its Relationship With Aging: CORDIOPREV Study

Background

Leukocyte telomere length (LTL) attrition has been associated with age-related diseases. Telomerase RNA Component (TERC) genetic variants have been associated with LTL; whereas fatty acids (FAs) can interact with genetic factors and influence in aging. We explore whether variability at the TERC gene locus interacts with FA profile and two healthy diets (low-fat diet vs Mediterranean diet [MedDiet]) modulating LTL, glucose metabolism, and inflammation status in coronary heart disease (CHD) patients.

Methods

Inflammation status (high-sensitivity C-reactive protein [hsCRP], glucose metabolism-glucose, insulin, and glycated hemoglobin [HbA1c], and homeostasis model assessment of insulin resistance [HOMA-IR]), LTL, FAs, and single nucleotide polymorphisms (SNPs) of the TERC gene (rs12696304, rs16847897, and rs3772190) were determined in 1,002 patients from the CORDIOPREV study (NCT00924937).

Results

We report an interaction of the TERC rs12696304 SNP with monounsaturated fatty acid (MUFA) affecting LTL (p interaction = .01) and hsCRP (p interaction = .03). Among individuals with MUFA levels above the median, CC individuals showed higher LTL and lower hsCRP than G-allele carriers. Moreover, MedDiet interacted with TERC rs12696304 SNP (p interaction = .03). Specifically, CC individuals displayed a greater decrease in hsCRP than G-allele carriers. These results were not adjusted for multiple statistical testing and p less than .05 was considered significant.

Conclusions

Our findings suggest that the TERC rs12696304 SNP interacts with MUFA improving inflammation status and telomere attrition related with CHD. Moreover, the MedDiet intervention improves the inflammatory profile in CC individuals compared with the G-allele carriers. These interactions could provide a right strategy for personalized nutrition in CHD patients.