Telomere Length Research Articles

The role of genetic and epigenetic factors on the development of cognitive deficits in patients with severe trauma after repeated anesthesia (literature review)

Introduction. When a severe combined injury occurs in a patient, various biochemical, humoral, cellular and pathophysiological mechanisms of protection against death occur. Immediately after receiving an injury, the patient is hospitalized in a hospital for medical care, where every effort is made to stabilize the condition, resorting to the appointment of various instrumental and laboratory tests. The development and course of traumatic illness, and treatment outcomes in patients with similar injuries are sometimes dramatically different. Based on this, it was suggested that there is a genetic basis for the regularity of the disease, as well as that exogenous factors themselves can affect certain molecular genetic markers, primarily telomere length.The objective was to summarize the current literature data on the study of changes in telomere length, as well as the influence of exogenous and endogenous factors on their shortening. To determine the prospects of studying the effect of polymorphic alleles of various genes on the development of a pathological condition in a certain cohort, namely the development of cognitive dysfunction in patients with severe trauma after repeated anesthesia.Materials and methods. The literature search and analysis was performed in the medical information systems PubMed and eLibrary, using the keywords «telomere», «trauma», «cognitive», and «anesthesia».Results. Since 1950, data on the study of human telomeres began to be published abroad. Between 2002 and the present, 39 articles were published on PubMed when searching for the keywords «anesthesia» and «telomeres»; by keywords «cognitive», «trauma», «telomeres» – 27. Most articles are devoted to the effect of childhood trauma on changes in telomere length, as well as the assessment of short telomeres in patients with various cognitive deficits. However, there are no articles devoted to studying the effect of repeated anesthesia, as an exogenous factor, on the genetic apparatus of a patient with severe combined trauma.Conclusion. The literature highlights the influence of various exogenous factors on the shortening of telomere length, especially in the context of childhood trauma, cognitive impairment in various observed groups. The section related to the effects of anesthesia and their number, the consequences for the genetic apparatus of a particular person, is open for study.

COVID-19 increases mortality in hemodialysis patients: exploring links with inflammation and telomere attrition.

An increased risk of mortality and hospitalization was consistently demonstrated in hemodialysis (HD) patients affected by pandemic coronavirus infection (COVID-19). In this study, we analyzed parameters that may impact mortality in COVID-19 HD patients, including neutrophil-to-lymphocyte ratio (NLR), lactate dehydrogenase (LDH), C-reactive protein (CRP), COVID-19 disease status and telomere length in peripheral blood cells (TL). A total of 130 chronic hemodialysis patients were enrolled and followed up for 18 months. Patients were categorized into groups based on their COVID-19 disease history and subsequent data about their survival status at the end of the study. Routine laboratory parameters were assessed using standard automated methods and TL was determined using the modified Cawthon method. Survival predictors were analyzed using Kaplan-Meier analysis. Deceased patients (30%) were older with higher body mass index (BMI), higher levels of LDH, NLR index, CRP and lower TL and lymphocytes count compared to survivors. Kaplan-Meier survival analysis showed six parameters were significant mortality predictors in the following order of significance: COVID-19 history, 2-years cardiovascular mortality risk score, NLR, TL, CRP, LDH. Using binary logistic regression analysis Summary risk score, a combination of these six parameters revealed as the best predictor of patient's survival in this group of parameters (log rank 25.4, p < 0.001). Compared to the general population, the mortality rate among HD patients persists at a higher level despite advancements in HD technology and patient care. The situation has been exacerbated by COVID-19, by significant increase in mortality rate among these patients.

Genetic liability to human serum metabolites is causally linked to telomere length: insights from genome-wide Mendelian randomization and metabolic pathways analysis.

Telomere has been recognized as a biomarker of accelerating aging, and telomere length (TL) shortening is closely related to diverse chronic illnesses. Human serum metabolites have demonstrated close correlations with TL maintenance or shortening in observational studies. Nevertheless, little is known about the underlying pathological mechanisms, and Mendelian randomization (MR) analysis of serum metabolites may provide a more comprehensive understanding of the potential biological process. We employed a two-sample MR analysis method to assess the causal links between 486 serum metabolites and TL. We applied the inverse-variance weighted (IVW) approach as our primary analysis, and to assure the stability and robustness of our results, additional analysis methods including the weighted median, MR-Egger, and weighted mode were conducted. MR-Egger intercept test was utilized to detect the pleiotropy. Cochran's Q test was implemented to quantify the extent of heterogeneity. Furthermore, the pathway analysis was conducted to identify potential metabolic pathways. We identified 11 known blood metabolites associated with TL. Among these metabolites, four were lipid (taurocholate, dodecanedioate, 5,8-tetradecadienoate, and 15-methylpalmitate), one amino acid (levulinate (4-oxovaleate)), one carbohydrate (lactate), one nucleotide (pseudouridine), one energy (phosphate), and three xenobiotics (2-hydroxyacetaminophen sulfate, paraxanthine, and ergothioneine). The known protective metabolites included levulinate (4-oxovaleate), dodecanedioate, 5,8-tetradecadienoate, lactate, phosphate, paraxanthine, and ergothioneine. Multiple metabolic pathways have been identified as being implicated in the maintenance of telomere length. Our MR analysis provided suggestive evidence supporting the causal relationships between 11 identified blood metabolites and TL, necessitating further exploration to clarify the mechanisms by which these serum metabolites and metabolic pathways may affect the progression of telomeres.

Paternal exercise induces antioxidant defenses by α-Klotho/Keap1 pathways in the skeletal muscle of offspring exposed to a high fat-diet without changing telomere length

Although previous studies demonstrated that the ancestral lifestyle can enhance the metabolic health of offspring exposed to an obesogenic diet, the specific connections between these positive effects in redox state and telomere length are unknown. We investigated the impact of paternal resistance training (RT) on stress-responsive signaling and the pathways involved in telomere homeostasis in skeletal muscle. This investigation encompassed both the fathers and first-generation litter exposed to a long-term standard diet (24 weeks) and high fat diet (HFD). Wistar rats were randomized into sedentary or trained fathers (8 weeks of resistance training). The offspring were obtained by mating with sedentary females. Upon weaning, male offspring were divided into four groups: offspring of sedentary or trained fathers exposed to either a control diet or HFD. The gastrocnemius was prepared for reverse transcription-quantitative polymerase chain reaction, immunoblotting, ELISA, and electron paramagnetic resonance spectroscopy. RT upregulated shelterin mRNA levels and antioxidant protein, preserving muscle telomere in fathers. Conversely, HFD induced a disturbance in the redox balance, which may have contributed to the offspring telomere shortening from sedentary fathers. Preconceptional paternal RT downregulates Kelch-like ECH-associated protein 1 (Keap1) mRNA levels in the skeletal muscle of progeny exposed to HFD, driving an increase in Glutathione reductase mRNA levels, Sod1 and Catalase protein levels to mitigate ROS production. Also, paternal exercise upregulates α-Klotho protein levels, mediating antioxidative responses without altering shelterin mRNA levels and telomere length. We provide the first in-depth analysis that the offspring's redox state seems to be directly associated with the beneficial effects of paternal exercise.

Tert promotes cardiac regenerative repair after MI through alleviating ROS-induced DNA damage response in cardiomyocyte

Telomerase reverse transcriptase (Tert) has been found to have a protective effect on telomeric DNA, but whether it could improve the repair of reactive oxygen species (ROS)-induced DNA damage and promote myocardial regenerative repair after myocardial infarction (MI) by protecting telomeric DNA is unclear. The immunofluorescence staining with TEL-CY3 and the TeloTAGGG Telomerase PCR ELISA kit were used to show the telomere length and telomerase activity. The heart-specific Tert-deletion homozygotes were generated by using commercial Cre tool mice and flox heterozygous mice for mating. We measured the telomere length and telomerase activity of mouse cardiomyocytes (CMs) at different days of age, and the results showed that they were negatively correlated with age. Overexpressed Tert could enhance telomerase activity and lengthen telomeres, thereby repairing the DNA damage induced by ROS and promoting CM proliferation in vitro. The in vivo results indicated that enhanced Tert could significantly improve cardiac function and prognosis by alleviating CM DNA damage and promoting angiogenesis post-MI. In terms of mechanism, DNA pulldown assay was used to identify that nuclear ribonucleoprotein A2B1 (hnRNPA2B1) could be an upstream regulator of Tert in CMs. Overexpressed Tert could activate the NF-κB signaling pathway in CMs and bind to the VEGF promoter in the endothelium to increase the VEGF level. Further immunoblotting showed that Tert protected DNA from ROS-induced damage by inhibiting ATM phosphorylation and blocking the Chk1/p53/p21 pathway activation. HnRNPA2B1-activated Tert could repair the ROS-induced telomeric DNA damage to induce the cell cycle re-entry in CMs and enhance the interaction between CMs and endothelium, thus achieving cardiac regenerative repair after MI.

Telomere length in young and middle-aged patients: relationship with cardiovascular risk factors

Aim. To evaluate the relationship between leukocyte telomere length (LTL) and cardiovascular risk factors in young and middle-aged patients without cardiovascular disease (CVD).Material and methods. This cross-sectional study involved 450 patients aged 30 [21;42] years. Risk factors and possible exclusion criteria was assessed through questionnaires and anthropometric examination. In all subjects, glucose concentration and lipid profile were assessed using the CardioChekPA express analyzer (USA, 2017), followed by calculation of integral metabolic indices: visceral adiposity index (VAI), body fat percentage, body adiposity index (BAI), lipid accumulation product (LAP). LTL was measured in whole blood samples using fluorimetry (Qubit 4 Singapore 2020) and reverse transcription polymerase chain reaction (QIAamp Blood Mini Kit, German 2022). Statistical analysis was carried out using the Statistica 10 program.Results. The prevalence of the studied risk factors in the main group corresponded to the general population. According to the correlation analysis, LTL was associated with age (r=-0,26; p&lt;0,05), smoking (r=-0,35; p&lt;0,05), obesity (r=-0,19; p&gt;0,05), neck circumference (NC) (r=-0,53; p&lt;0,05), diastolic blood pressure (r=-0,31; p&lt;0,05), cholesterol (r=-0,64; p&lt;0,05), high-density lipoproteins (HDL) (r=0,59; p&lt;0,05) and low-density lipoproteins (r=-0,52; p&lt;0,05), triglycerides (r=-0,46; p&lt;0,05), glucose (r=-0,33; p&lt;0,05), LAP (r=-0,4; p&lt;0,05), VAI (r=-0,57; p&lt;0,05) and BAI (r=-0,32; p&lt;0,05). According to the multivariate regression analysis, LTL was associated with age (B=-0,04, Std. Err. of B=0,02, p=0,03), smoking (B=-0,87, Std. Err. of B=0,26, p=0,001), NC (B=-0,23, Std. Err. of B=0,07, p=0,001), total cholesterol levels (B=-0,37, Std. Err. of B=0,87, p&lt;0,001), HDL (B=0,59, Std. Err. of B=0,24, p=0,018), LAP (B=-0,01, Std. Err. of B=0,02, p&lt;0,011), VAI (B=-0,37, Std. Err. of B=0,16, p=0,025).Conclusion. LTL is interconnected with cardiovascular risk factors, which determines the significance of their participation in CVD development and biological aging in young and middle-aged people.

Separation of telomere protection from length regulation by two different point mutations at amino acid 492 of RTEL1.

RTEL1 is an essential DNA helicase that plays multiple roles in genome stability and telomere length regulation. A variant of RTEL1 with a lysine at position 492 is associated with short telomeres in Mus spretus , while a conserved methionine at this position is found in M. musculus , which has ultra-long telomeres. In humans, a missense mutation at this position ( Rtel1 M492I ) causes a fatal telomere biology disease termed Hoyeraal-Hreidarsson syndrome (HHS). Introducing the Rtel1 M492K mutation into M. musculus shortened the telomeres of the resulting strain, termed 'Telomouse', to the length of human telomeres. Here, we report on a mouse strain carrying the Rtel1 M492I mutation, termed 'HHS mouse'. The HHS mouse telomeres are not as short as those of Telomice but nevertheless they display higher levels of telomeric DNA damage, fragility and recombination, associated with anaphase bridges and micronuclei. These observations indicate that the two mutations separate critical functions of RTEL1: M492K mainly reduces the telomere length setpoint, while M492I predominantly disrupts telomere protection. The two mouse models enable dissecting the mechanistic roles of RTEL1 and the different contributions of short telomeres and DNA damage to telomere biology diseases, genomic instability, cancer, and aging.

Sex-specific modulating role of social support in the associations between oxidative stress, inflammation, and telomere length in older adults.

Telomere length, a biomarker of human aging, is related to adverse health outcomes. Growing evidence indicates that oxidative stress and inflammation contributes to telomere shortening, whereas social support may protect from telomere shortening. Despite sex differences in telomere length and social support, little is known about whether there are sex differences in the relationship between oxidative stress/inflammation and telomere length, and sex-specific moderating roles of social support in older adults. Using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2002, this study assessed whether the associations between oxidative stress/inflammation and telomere length vary with sex and explored social support as a moderator in these associations among 2289 older adults. Oxidative stress was measured based on serum Gamma-glutamyl transferase (GGT), and inflammation was measured based on C-reactive protein (CRP). After adjusting for the covariates, GGT was significantly associated with telomere length in females only (β = - 0.037, 95% CI = - 0.070, - 0.005), while CRP was associated with telomere length in males only (β = - 0.019, 95% CI = - 0.035, - 0.002). Moreover, high social support mitigated the negative association between GGT and telomere length, which was more evident in females. Furthermore, social support moderated the association between CRP and telomere length in males aged 70 and above. Our findings indicated that biological mechanisms related to telomere length may vary with sex, while social support plays a sex-specific moderating role.

Micronutrient intake and telomere length: findings from the UK Biobank.

To investigate whether micronutrient intake from food as well as the regular uptake of specific vitamins and/or minerals are associated with leucocyte telomere length (LTL). This is a cross-sectional study using data from 422,693 UK Biobank participants aged from 40 to 69 years old, during 2006-2010. LTL was measured as the ratio of telomere repeat number to a single-copy gene and was loge-transformed and z-standardized (z-LTL). Information concerning supplement use was collected at baseline through the touchscreen assessment, while micronutrient intake from food were self-reported through multiple web-based 24h recall diaries. The association between micronutrient intake or supplement use and z-LTL was assessed using multivariable linear regression models adjusting for demographic, lifestyle and clinical characteristics. About 50% (n = 131,810) of the participants, with complete data on all covariates, self-reported regular supplement intake. Whilst overall supplement intake was not associated with z-LTL, trends toward shorter z-LTL with regular vitamin B (-0.019 (95% CI: -0.041; 0.002)) and vitamin B9 (-0.027 (-0.054; 0.000)) supplement intake were observed. z-LTL was associated with food intake of pantothenic acid (-0.020 (-0.033; -0.007)), vitamin B6 (-0.015 (-0.027; -0.003)), biotin (0.010 (0.002; 0.018)) and folate (0.016 (0.003; 0.030)). Associations of z-LTL with these micronutrients were differentiated according to supplement intake. Negative associations equivalent to a year or less of age-related change in LTL between micronutrient intake and LTL were observed. Due to this small effect, the clinical importance of the associations and any relevance to the effects of vitamin and micronutrient intake toward chronic disease prevention remains uncertain.

Investigation of G-Quadruplex DNA-Mediated Charge Transport for Exploring DNA Oxidative Damage in Telomeres.

The human telomeric DNA 3' single-stranded overhang comprises tandem repeats of the sequence d(TTAGGG), which can fold into the stable secondary structure G-quadruplex (G4) and is susceptible to oxidative damage due to the enrichment of G bases. 8-Oxoguanine (8-oxoG) formed in telomeric DNA destabilizes G4 secondary structures and then inhibits telomere functions such as the binding of G4 proteins and the regulation of the length of telomeres. In this work, we developed a G4-DNA self-assembled monolayer electrochemical sensing interface using copper-free click chemistry based on the reaction of dibenzocyclooctyl with azide, resulting in a high yield of DNA tethers with order and homogeneity surfaces, that is more suitable for G-quadruplex DNA charge transport (CT) research. At high DNA coverage density surfaces, G-quadruplex DNA is 4 times more conductive than double-stranded DNA owing to the well-stacked aromatic rings of G-quartets acting as good charge transfer channels. The effect of telomeric oxidative damage on G-quadruplex-mediated CT is investigated. The accommodation of 8-oxoG at G sites originally in the syn or anti conformation around the glycosyl bond in the nonsubstituted hTel G-quadruplex causes structural perturbation and a conformational shift, which disrupts the π-stack, affecting the charge transfer and attenuating the electrochemical signal. The current intensity was found to correlate with the amount of 8-oxodG, and the detection limit was estimated to be approximately one lesion in 286 DNA bases, which can be converted into 64.7 fmol on the basis of the total surface DNA coverage. The improved G4-DNA order and homogeneity sensing interface represent a major step forward in this regard, providing a reliable and controlled electrochemical platform for the accurate measurement and diagnosis of G4-DNA oxidative damage.

Exploring the impact of diabetes on aging: insights from TERT and COL1A1 methylation.

Aging, a multifaceted biological process, leads to diminished physical performance, especially in older adults with diabetes, where a mismatch between biological and chronological age is noticeable. Numerous studies have demonstrated that diabetes accelerates aging at the cellular and organ levels. Notable aging markers are telomerase reverse transcriptase (TERT), related to telomere length, and type 1 chain collagen (COL1A1), a key component of skin collagen. Additionally, age-related methylation increases, as revealed through methylation analysis, augmenting aspects of aging. However, the detailed interplay between aging and diabetes, particularly regarding methylation, remains underexplored and warrants further study to elucidate the biological links between the two. In this study, we elucidate the modulatory influence of diabetes on the aging process, focusing specifically on the modifications in TERT in the kidney and COL1A1 in the skin using mice of Swiss Webster strain as the diabetes model. Specimens were categorized into three distinct chronological cohorts: chronologically young (16 weeks; n = 5), chronologically old (40 weeks; n = 5), and a periodically assessed group (16 weeks; n = 30), from which five mice were systematically sacrificed on a weekly basis. Our findings reveal a marked impact of diabetes on the methylation statuses of TERT and COL1A1, characterized by an elevation in methylation levels within the periodic group (1st-6th week) and a simultaneous, progressive attenuation in the expression of TERT and COL1A1 genes. The observed alterations in the methylation levels of TERT and COL1A1 propound the hypothesis that diabetes potentially expedites the aging process, concomitantly impinging on the production of TERT and COL1A, ostensibly through the mechanism of promoter gene hypermethylation.

Association and causal impact of TERT genetic variants on peripheral blood leukocyte telomere length and cerebral small vessel disease risk in a Chinese Han population: a mendelian randomization analysis

BackgroundPrevious observational studies have highlighted potential relationships between the telomerase reverse transcriptase (TERT) gene, short leukocyte telomere length (LTL), and cerebrovascular disease. However, it remains to be established as to whether TERT gene variants are associated with an elevated risk of cerebral small vessel disease (CSVD), and whether there is a causal relationship between LTL and CSVD.MethodsFive TERT single nucleotide polymorphisms (SNPs) were analyzed in 307 CSVD patients and 320 healthy controls in whom LTL values were quantified. Allele models and four genetic models were used to explore the relationship between these SNP genotypes and CSVD risk. A Mendelian randomization analysis of CSVD risk was then performed using LTL-related SNPs and the polygenic risk score (PRS) constructed from these SNPs as genetic instrumental variables to predict the causal relationship between LTL and CSVD risk.ResultsModel association analyses identified two SNPs that were significantly associated with CSVD risk. LTL was significantly correlated with age (P < 0.001), and the MR analysis revealed an association between short LTL and an elevated risk of CSVD. PRS-based genetic prediction of short LTLs was also significantly related to an elevated CSVD risk.ConclusionMultiple genetic models and MR results indicate that TERT gene SNPs may be related to an elevated risk of CSVD, and that shorter LTL may be causally linked to such CSVD risk.

X-chromosome inactivation pattern and telomere length in recurrent pregnancy loss

Recurrent pregnancy loss is a reproductive disorder affecting about 1 to 5 % of pregnant women worldwide that requires our attention, especially considering that about 50 % of cases are idiopathic. The present study is focused on testing a possible association between extreme skewed X-chromosome inactivation patterns and/or shortened telomeres with idiopathic cases since both are considered non-consensual potential causes underlying recurrent pregnancy loss in the scientific community. For this purpose, two groups of women were analyzed and compared: a group of women with idiopathic recurrent pregnancy loss and a second group of age-matched women with proven fertility, and both X-chromosome inactivation patterns and telomere length were measured and compared from maternal DNA extracted from peripheral blood. Our data showed no statistically significant differences between groups, suggesting no association between extreme skewed X-chromosome inactivation or shortened telomeres with recurrent pregnancy losses. Additionally, the effect of maternal age on both X-chromosome inactivation pattern and telomere length was tested, but no significant correlation was observed between advanced maternal age and extreme skewed X-chromosome inactivation or telomere shortening. This study represents one more valid contribution to the investigation of causes underlying recurrent pregnancy loss suggesting that, new variables may be considered since the pattern of X-chromosome inactivation and telomere length do not seem to be related to this reproductive disorder. Briefly, considering its clinical relevance, it is mandatory a continuous effort in the scientific community to cover new potential recurrent pregnancy loss-related causes.

Leukocyte Telomere Length and Mitochondrial DNA Copy Number in Treatment-Resistant Depression and Response to Electroconvulsive Therapy: A Pilot Longitudinal Study.

In this study, we investigated if changes in leukocyte telomere length (LTL) and mitochondrial DNA copy number (mtDNA-cn), 2 markers of cellular aging, are associated with treatment-resistant depression (TRD) and with response to electroconvulsive therapy (ECT). LTL and mtDNA-cn were measured in 31 TRD patients before (T0), 1 week (T1), and 4 weeks (T2) after the ECT course, as well as in a sample of 65 healthy controls. TRD patients had significantly shorter LTL and higher mtDNA-cn compared with healthy controls at baseline. In the TRD sample, LTL was inversely correlated with Montgomery-Åsberg Depression Rating Scale scores at baseline. Baseline levels of LTL or mtDNA-cn were not correlated with response to ECT. Similarly, changes in LTL or mtDNA-cn were not associated with response to ECT either when considered as a dichotomous trait (responders vs nonresponders) or as a percentage change in symptoms improvements. Ours is the first longitudinal study exploring the role of LTL and mtDNA-cn in response to ECT. Findings of this pilot investigation suggest that LTL and mtDNA-cn may constitute disease biomarkers for TRD but are not involved in response to ECT.

Association of Telomere Length in T Lymphocytes, B Lymphocytes, NK Cells and Monocytes with Different Forms of Age-Related Macular Degeneration.

Age plays a primary role in the development of age-related macular degeneration (AMD). Telomere length (TL) is one of the most relevant biomarkers of aging. In our study, we aimed to determine the association of TL with T lymphocytes, B lymphocytes, NK cells or monocytes with different forms of AMD. Our study included 62 patients with AMD: geographic atrophy (GA), neovascular AMD (NVAMD) with and without macular atrophy and 22 healthy controls. Each leukocyte subtype was isolated from peripheral blood by immunomagnetic separation, and the DNA was purified. The TL in the genomic DNA was determined using qPCR by amplifying the telomere region with specific oligonucleotide primers and normalizing to the control gene. Statistical analysis was performed using R version 4.5.1. We observed a statistically significant increase in TL in the T cells between the control and NVAMD groups but not for the GA group. The B cells and monocytes showed a significant decrease in TL in all AMD groups. The TL in the NK cells did not decrease in any of the AMD groups. The TL in the monocytes had the strongest association with AMD. It reflects a person's "telomeric status" and may become a diagnostic hallmark of these degenerative processes.

Causal Associations of Cognitive Reserve and Hierarchical Aging-Related Outcomes: A Two-Sample Mendelian Randomization Study.

Two-sample Mendelian randomization methods were used to explore the causal effects of cognitive reserve proxies, such as educational attainment, occupational attainment, and physical activity (PA), on biological (leukocyte telomere length), phenotypic (sarcopenia-related features), and functional (frailty index and cognitive performance) aging levels. Educational attainment had a potential protective effect on the telomere length (β = 0.10, 95% CI: 0.08-0.11), sarcopenia-related features (β = 0.04-0.24, 95% CI: 0.02-0.27), frailty risk (β = -0.31, 95% CI: -0.33 to -0.28), cognitive performance (β = 0.77, 95% CI: 0.75-0.80). Occupational attainment was causally related with sarcopenia-related features (β = 0.07-0.10, 95% CI: 0.05-0.14), and cognitive performance (β = 0.30, 95% CI: 0.24-0.36). Device-measured PA was potentially associated with one sarcopenia-related feature (β = 0.14, 95% CI: 0.03-0.25). Our findings support the potential causality of educational attainment on biological, phenotypic, and functional aging outcomes, of occupational attainment on phenotypic and functional aging-related outcomes, and of PA on phenotypic aging-related outcomes.

Causal relationship between telomere length and osteonecrosis: Bidirectional two-sample Mendelian randomization analysis.

Recent mounting evidence suggests that shortening of telomere length (TL) is associated with impaired bone health; yet, a genetic causal relationship between TL and osteonecrosis remains uncertain. This study aimed to investigate the potential causal relationship between TL and osteonecrosis using bidirectional two-sample Mendelian randomization (MR). Genome-wide association study summary statistics for TL were sourced from the IEU Open genome-wide association study project, while osteonecrosis data were obtained from the FinnGen Biobank database. A range of MR methodologies-including inverse variance weighting, MR-Egger, weighted median, simple mode, and weighted mode-were utilized for analysis, along with the MR-Egger intercept method for horizontal pleiotropy assessment, and Cochran Q and leave-one-out methods for heterogeneity testing. The forward MR analysis indicated a significant causal relationship between TL and osteonecrosis, suggesting that genetically predicted shorter TL is associated with an elevated risk of developing osteonecrosis (OR = 0.611, 95% confidence interval 0.394-0.948, P = .028). The reverse MR analysis revealed no significant influence of osteonecrosis on TL (OR = 0.999, 95% confidence interval 0.994-1.005, P = .802). Analyses for heterogeneity and horizontal pleiotropy yielded robust results. Our study demonstrates that individuals with shorter TL have an increased risk of developing osteonecrosis, whereas osteonecrosis has no effect on TL.

DNA methylation-estimated phenotypes, telomere length and risk of ischemic stroke: epigenetic age acceleration of screening and a Mendelian randomization study.

Aging is a complex biological process that may be accelerated in certain pathological conditions. DNA methylation age (DNAmAge) has emerged as a biomarker for biological age, which can differ from chronological age. This research peels back the layers of the relationship between fast-forward aging and ischemic stroke, poking and prodding the potential two-way causal influences between stroke and biological aging indicators. We analyzed a cohort of ischemic stroke patients, comparing DNAmAge with chronological age to measure age acceleration. We assessed variations in age acceleration among stroke subtypes and between sexes. Using Mendelian randomization, we examined the causal links between stroke, aging biomarkers like telomere length, and age acceleration's effect on stroke risk. Our investigation reveals a pronounced association between ischemic stroke and age acceleration, most notably in patients with cardioembolic strokes, who exhibited a striking median difference of 9 years between DNAmAge and chronological age. Furthermore, age acceleration differed significantly across stroke subtypes and was higher in women than in men. In terms of causality, MR analysis indicated a modest negative effect of stroke on telomere length, but no causal effect of age phenotypes on stroke or its subtypes. However, some indication of a potential causal effect of ischemic stroke on PhenoAge acceleration was observed. The study provides insight into the relationship between DNAmAge and ischemic stroke, particularly cardioembolic stroke, and suggests possible gender differences. These insights carry profound clinical significance and set stage for future investigations into the entwined pathways of stroke and accelerated aging.

Causal Relationship between Aging and Anorexia Nervosa: A White-Matter-Microstructure-Mediated Mendelian Randomization Analysis.

This study employed a two-step Mendelian randomization analysis to explore the causal relationship between telomere length, as a marker of aging, and anorexia nervosa and to evaluate the mediating role of changes in the white matter microstructure across different brain regions. We selected genetic variants associated with 675 diffusion magnetic resonance imaging phenotypes representing changes in brain white matter. F-statistics confirmed the validity of the instruments, ensuring robust causal inference. Sensitivity analyses, including heterogeneity tests, horizontal pleiotropy tests, and leave-one-out tests, validated the results. The results show that telomere length is significantly negatively correlated with anorexia nervosa in a unidirectional manner (p = 0.017). Additionally, changes in specific white matter structures, such as the internal capsule, corona radiata, posterior thalamic radiation, left cingulate gyrus, left longitudinal fasciculus, and left forceps minor (p < 0.05), were identified as mediators. These findings enhance our understanding of the neural mechanisms, underlying the exacerbation of anorexia nervosa with aging; emphasize the role of brain functional networks in disease progression; and provide potential biological targets for future therapeutic interventions.

Shortening of telomere length may be associated with inflammatory cytokine levels in patients with bipolar disorder

BackgroundBipolar disorder (BD) is hypothesized to be associated with accelerated biological aging. Telomere length (TL) is a biomarker of aging, and although TL decreases with each cell division, the rate of telomere shortening may be affected by inflammation. We aimed to investigate whether TL is decreased in BD patients and to determine the association between TL and inflammatory markers in such patients. Methods137 BD patients and 118 healthy controls (HCs) were recruited. Leukocyte TL and plasma levels of cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-8, IL-6, IL-10, transforming growth factor (TGF)-β1], C-reactive protein (CRP), and brain-derived neurotrophic factor (BDNF) were assessed. ResultsTL did not differ significantly between the BD patients and HCs after adjustment for potential confounding factors (P = 0.79). TL was significantly negatively associated with age (β = −0.007, P < 0.001). In addition, log TNF-α levels were significantly negatively associated with TL (P = 0.009), in both the BD patients (P = 0.02) and HCs (P = 0.05). ConclusionWe found a significant association between TNF-α levels and TL shortening in both BD patients and HCs. However, BD patients did not display increased TL shortening relative to HCs. Studies that involve larger sample sizes and control for the heterogeneity of BD participants will be needed.