Association of telomere length and mitochondrial DNA copy number, two biomarkers of biological aging, with the risk of venous thromboembolism

Combination of Biological Aging and Genetic Susceptibility Helps Identifying At-Risk Population of Venous Thromboembolism: A Prospective Cohort Study of 394 041 Participants

Phenotypic age acceleration (PhenoAgeAccel) is a novel clinical aging indicator. This study was carried out to investigate the relationship between PhenoAgeAccel and the incidence of VTE, as well as to integrate PhenoAgeAccel with genetic susceptibility to improve risk stratification of VTE. The study included 394 041 individuals from the UK Biobank. Phenotypic age was calculated based on actual age and clinical biomarkers. PhenoAgeAccel presents the residual obtained from a linear regression of phenotypic age against actual age, reflecting the rate of aging. Significant associations were observed between PhenoAgeAccel and higher risk of VTE (Hazard ratio [HR] 1.37, 95% CI: 1.32-1.42), deep vein thrombosis (DVT, HR 1.35, 95% CI: 1.29-1.42), and PE (pulmonary embolism, HR 1.41, 95% CI: 1.34-1.48) in the findings. PhenoAgeAccel exhibited a significant additive interaction with genetic susceptibility. Biologically older participants with high genetic risk have a 3.83 (95% CI: 3.51-4.18) folds risk of VTE, a 3.59 (95% CI: 3.21-4.03) folds risk of DVT, and 4.39 (95% CI: 3.88-4.98) folds risk of PE, in comparison to biologically younger participants with low genetic risk. Mediation analyses indicated that PhenoAgeAccel mediated approximately 6% of the association between cancer and VTE, and about 20% of the association between obesity and VTE. Our study indicated that PhenoAgeAccel is significantly associated with higher risk of VTE, and can be combined with genetic risk to improve VTE risk stratification. Additionally, PhenoAgeAccel holds promise as a clinical biomarker for guiding targeted prevention and treatment strategies for VTE.

The Role of Mitochondrial DNA Copy Number in Venous Thromboembolism: Insights from a 2-Sample Mendelian Randomization Study

BACKGROUND

Venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), is the third most common cardiovascular disease. A low amount of mitochondrial DNA copy number (mtDNA-CN) reflects mitochondrial dysfunctions and has been associations with arterial cardiovascular diseases. However, the role of mtDNA-CN in venous cardiovascular disease was unclear. We aimed to implement a 2-sample Mendelian randomization analysis to approximate the causal nature of these relationships.

METHODS

Genetic instruments for VTE, PE, and DVT were derived from the largest available genome-wide association study datasets. The inverse variance weighted method was used as the primary analytical approach, with sensitivity analyses performed to assess horizontal pleiotropy and heterogeneity. The reverse Mendelian randomization analysis was conducted using genetic instruments for mtDNA-CN.

RESULTS

The genetically instrumented mtDNA-CN levels did not exhibit a causal effect on VTE (P = 0.224), DVT (P = 0.190), and PE (P = 0.571). However, genetically predicted VTE (odds ratio (OR) = 0.569, 95% confidence interval (CI) = 0.341-0.952; P = 0.032), PE (OR = 0.991, 95% CI = 0.983-0.999; P = 0.037), and DVT (OR = 0.429, 95% CI = 0.207-0.890; P = 0.023) were associated with decreased mtDNA-CN levels in the inverse variance weighted analysis. Sensitivity and replication analyses confirmed the robustness of these findings.

CONCLUSION

Our findings did not support a causal effect of mtDNA-CN in the development of VTE, but provide direct evidence that VTE may lead to reduced mtDNA-CN levels. These results suggest that mtDNA-CN as a biomarker of VTE in clinical practice.

Mitochondrial DNA copy number and its association with venous thromboembolism in patients with cancer

Venous thromboembolism (VTE) is a common and serious complication among cancer patients. Mitochondrial DNA (mtDNA) copy number is known to influence various cellular pathways involved in cancer development. While an association between reduced mtDNA and VTE risk in non-cancer patients was previously reported, its relationship with VTE in cancer patients remains unclear. Therefore, we aimed to investigate the association between mtDNA copy number and VTE risk in a nested-case control study of 48 patients from the Vienna Cancer and Thrombosis Study (CATS), a prospective observational cohort study. The mtDNA copy number was measured in equally distributed age, sex, cancer type, and stage matched patients with and without VTE using a qPCR-based method. Of the 48 patients, 24 were diagnosed with VTE (median age [IQR] 62 [57-60] years, 54.2 % female) and 24 had no VTE event (median age [IQR] 63 [58-71] years, 54.2 % female). We found that patients who developed VTE had lower mtDNA copy numbers compared to those without VTE (216.73 [167.99-401.39] vs 301.47 [210.66-526.84]). Multivariable analysis adjusting for chronological age, D-dimer, sex, cancer stage and BMI revealed that each 10-unit increase in mtDNA copy number decreased the odds of VTE occurrence by 5.9 % (p = 0.021). Patients with distant metastatic cancer (M1) had lower mtDNA copy numbers than those without distant metastasis at study inclusion (220.34 [172.67-323.70] vs 328.48 [213.89-556.68; p = 0.052). Overall, our findings suggest a potential link between reduced mtDNA copy number and increased VTE risk in cancer patients.

Causal association between circulating α-Klotho levels and venous thromboembolism: a two-sample Mendelian randomization study

BACKGROUND

α-Klotho may involve in the occurrence and development of venous thromboembolism (VTE). However, the underlying relationship between circulating α-Klotho levels and VTE is still unclear.

METHODS

This two-sample Mendelian Randomization (MR) study aims to explore the causal associations of circulating α-Klotho levels with different types of venous thromboembolism. Data of exposure and outcomes were extracted from the genome-wide association study (GWAS) of the MRC Integrative Epidemiology Unit (MRC-IEU). The fixed inverse variance weighted (IVW), MR-Egger, MR-Robust Adjusted Profile Score (RAPS) and the weighted-median methods were utilized to investigate the causal associations of circulating α-Klotho levels with different types of VTE. The effect size was expressed as odds ratios (ORs) and 95% confidence intervals (CIs), and the False Discovery Rate (FDR) test was used for correction. The MR scatter plot and leave-one-out test were used for sensitivity analysis. In addition, reverse causal associations were assessed.

RESULTS

IVW estimates suggested that an elevated circulating α-Klotho level was associated with lower odds of deep vein thrombosis (DVT) of lower extremities (OR = 0.992, 95%CI: 0.986-0.998, P = 0.0074), pulmonary embolism (PE) (OR = 0.474, 95%CI: 0.255-0.881, P = 0.0183), and DVT of lower extremities combined with PE (OR = 0.984, 95%CI: 0.971-0.997, P = 0.0175). However, after the FDR correction, only negatively causal association between circulating α-Klotho level and increased odds of lower-extremity DVT was statistically significant (FDR P = 0.0296). Also, there were no reverse causal associations between the circulating α-Klotho levels and different types of VTE (all P > 0.05). Additionally, both the MR scatter plots and leave-one-out test results showed that these causal associations were relatively robust.

CONCLUSION

An elevated circulating α-Klotho levels was associated with lower risk of DVT of lower extremities, PE, and DVT of lower extremities combined with PE, indicating α-Klotho has the potential to act as a target for early screening or treatment for VTE. However, the specific mechanism that α-Klotho influencing the occurrence of VTE still needed further exploration.

Association of clonal haematopoiesis with recurrent venous thromboembolism: A case-control study

Venous thromboembolism (VTE) is the third most common cardiovascular disease. Clonal haematopoiesis (CH) is linked to cardiovascular disease risk, but its potential association with VTE remains poorly understood. We assessed the prevalence of CH in patients with recurrent VTE (n = 107; median age [IQR] 57 [48-63] years, 44.9% female) and matched healthy controls (n = 127; median age [IQR] 53 [45-60] years, 51.2% female) to investigate a putative association of CH with VTE risk. We detected 12 CH-associated mutations in 11 (10.3%) VTE cases and six mutations in 5 (3.9%) controls. Thus, patients with recurrent VTE tended to have higher odds of presenting with CH compared to controls (OR: 2.74, 95% CI: 0.95-9.16). Moreover, the odds of detecting CH were significantly higher in VTE cases in the subgroup of individuals without thrombophilia (OR: 4.58, 95% CI: 1.48-15.99). VTE cases with CH showed elevated platelet counts compared to cases and controls without CH (median [IQR]: 292 [254-298], 223 [198-260] and 220 [185-259] × 109/L; both p < 0.01). Fibrinogen, sP-selectin, D-dimer and hsCRP levels did not differ according to CH status. Overall, we identified a trend for an association between CH and recurrent VTE, particularly in individuals without underlying thrombophilia, warranting further research in this patient group.

Biological Aging and Venous Thromboembolism: A Review of Telomeres and Beyond

Although venous thromboembolism (VTE) is the third most common cardiovascular disease, and the risk of VTE increases sharply with advancing age, approximately 40% of VTE cases are currently classified as unprovoked, highlighting the importance of risk factor research. While chronological aging is associated with the risk of VTE, the association with biological aging remains unclear. Biological aging is highly complex, influenced by several dysregulated cellular and biochemical mechanisms. In the last decade, advancements in omics methodologies provided insights into the molecular complexity of biological aging. Techniques such as high-throughput genomics, epigenomics, transcriptomics, proteomics, and metabolomics analyses identified and quantified numerous epigenetic markers, transcripts, proteins, and metabolites. These methods have also revealed the molecular alterations organisms undergo as they age. Despite the progress, there is still a lack of consensus regarding the methods for assessing and validating these biomarkers, and their application lacks standardization. This review gives an overview of biomarkers of biological aging, including telomere length, and their potential role for VTE. Furthermore, we critically examine the advantages and disadvantages of the proposed methods and discuss possible future directions for investigating biological aging in VTE.

Causal Relationship between Meat Intake and Biological Aging: Evidence from Mendelian Randomization Analysis

Existing research indicates that different types of meat have varying effects on health and aging, but the specific causal relationships remain unclear. This study aimed to explore the causal relationship between different types of meat intake and aging-related phenotypes. This study employed Mendelian randomization (MR) to select genetic variants associated with meat intake from large genomic databases, ensuring the independence and pleiotropy-free nature of these instrumental variables (IVs), and calculated the F-statistic to evaluate the strength of the IVs. The validity of causal estimates was assessed through sensitivity analyses and various MR methods (MR-Egger, weighted median, inverse-variance weighted (IVW), simple mode, and weighted mode), with the MR-Egger regression intercept used to test for pleiotropy bias and Cochran's Q test employed to evaluate the heterogeneity of the results. The findings reveal a positive causal relationship between meat consumers and DNA methylation PhenoAge acceleration, suggesting that increased meat intake may accelerate the biological aging process. Specifically, lamb intake is found to have a positive causal effect on mitochondrial DNA copy number, while processed meat consumption shows a negative causal effect on telomere length. No significant causal relationships were observed for other types of meat intake. This study highlights the significant impact that processing and cooking methods have on meat's role in health and aging, enhancing our understanding of how specific types of meat and their preparation affect the aging process, providing a theoretical basis for dietary strategies aimed at delaying aging and enhancing quality of life.

Toxic metals and essential trace elements in placenta and their relation to placental function

INTRODUCTION

Placental function is essential for fetal development, but it may be susceptible to malnutrition and environmental stressors.

OBJECTIVE

To assess the impact of toxic and essential trace elements in placenta on placental function.

METHODS

Toxic metals (cadmium, lead, mercury, cobalt) and essential elements (copper, manganese, zinc, selenium) were measured in placenta of 406 pregnant women in northern Sweden using ICP-MS. Placental weight and birth weight were obtained from hospital records and fetoplacental weight ratio was used to estimate placental efficiency. Placental relative telomere length (TL) and mitochondrial DNA copy number (mtDNAcn) were determined by quantitative PCR (n = 285). Single exposure-outcome associations were evaluated using linear or spline regression, and joint associations and interactions with Bayesian kernel machine regression (BKMR), all adjusted for sex, maternal smoking, and age or BMI.

RESULTS

Median cadmium, mercury, lead, cobalt, copper, manganese, zinc, and selenium concentrations in placenta were 3.2, 1.8, 4.3, 2.3, 1058, 66, 10626, and 166 μg/kg, respectively. In the adjusted regression, selenium (>147 μg/kg) was inversely associated with placental weight (B: -158; 95 % CI: -246, -71, per doubling), as was lead at low selenium (B: -23.6; 95 % CI: -43.2, -4.0, per doubling). Manganese was positively associated with placental weight (B: 41; 95 % CI: 5.9, 77, per doubling) and inversely associated with placental efficiency (B: -0.01; 95 % CI: -0.019, -0.004, per doubling). Cobalt was inversely associated with mtDNAcn (B: -11; 95 % CI: -20, -0.018, per doubling), whereas all essential elements were positively associated with mtDNAcn, individually and joint.

CONCLUSION

Among the toxic metals, lead appeared to negatively impact placental weight and cobalt decreased placental mtDNAcn. Joint essential element concentrations increased placental mtDNAcn. Manganese also appeared to increase placental weight, but not birth weight. The inverse association of selenium with placental weight may reflect increased transport of selenium to the fetus in late gestation.