Shortened telomere length in patients with depression: A meta-analytic study

The relationship between leukocyte telomere length and risk of depression and anxiety: Evidence from UK Biobank

BACKGROUND

Telomere length is a cellular aging marker implicated in various health outcomes. A growing body of evidence suggests a link between leukocyte telomere length (LTL) and mental health outcomes. However, there have been no studies focused on the relationship between LTL and the future risk of depression and anxiety. This study aimed to investigate the associations between LTL and depression/anxiety, examining both cross-sectional prevalence and prospective incidence.

METHODS

Data from 364,331 UK Biobank participants were analyzed. LTL was measured at baseline, and mental health status was assessed through hospital records and online surveys. Logistic regression and Cox proportional hazards models were employed for cross-sectional and prospective analyses with appropriate adjustment, respectively.

RESULTS

The mean (SD) age of the subjects was 57.03 (13.34) years and follow-up duration was 8.80 (5.39) years. Cross-sectionally, shorter LTL was associated with increased odds of depression (OR: 1.401, 95 % CI: 1.291-1.521) and anxiety (1.347 (1.198-1.515)) at baseline, which remained significant after adjustment. Among those free of depression/anxiety at baseline, baseline shorter LTL was associated with a higher risk of incident depression (HR: 1.615, 95 % CI: 1.447-1.803) and anxiety (1.430 (1.293-1.581)) during follow-up period. These associations remained robust after adjusting for various covariates.

CONCLUSIONS

Our findings indicated an association between shorter telomeres and an increased risk of prevalent depression/anxiety and shorter telomeres precede the onset of these mental health conditions. Considering the potential clinical implications, our study underscores the relevance of LTL as a predictive tool for identifying individuals at risk of developing depression and anxiety.

Association between telomere length with alcohol use disorder and internalizing/externalizing comorbidities in a Brazilian male sample

BACKGROUND

Shortening telomere length (TL) is an important ageing marker associated with substance use disorder (SUD). However, the influence of psychiatric and clinical comorbidities and alcohol-related outcomes has not been much explored in the context of TL in individuals with alcohol use disorder (AUD) and may be a source of heterogeneity in AUD studies. Therefore, our aim was to investigate the influence of AUD, alcohol-related outcomes, and common psychiatric comorbidities on TL in men with AUD and healthy controls (HC).

METHODS

Men with AUD (n = 108, mean age = 52.4, SD = 8.6) were recruited in a detoxification unit, and HC (n = 80, mean age = 50.04, SD = 9.1) from the blood bank, both located in Brazil. HC had no current or lifetime diagnosis of any substance use disorder. Psychiatric comorbidities were assessed using SCID-I. TL ratio was measured in triplicates using quantitative multiplex PCR.

RESULTS

Telomere length did not differ between individuals with AUD and HC (p = 0.073) or was associated with AUD-related outcomes, trauma, or clinical comorbidities. Individuals with externalizing disorders had longer TL when comparing with those with internalizing disorders (p = 0.018) or without comorbidity (p = 0.018).

CONCLUSION

Our findings indicate that TL was influenced by the presence of psychiatric comorbidity rather than case or control status. These results were adjusted for potential confounders, such as age.

Hydroalcoholic Extract of Centella asiatica and Madecassic Acid Reverse Depressive-Like Behaviors, Inflammation and Oxidative Stress in Adult Rats Submitted to Stress in Early Life

Major depressive disorder (MDD) is a severe disorder that causes enormous loss of quality of life, and among the factors underlying MDD is stress in maternal deprivation (MD). In addition, classic pharmacotherapy has presented severe adverse effects. Centella asiatica (C. asiatica) demonstrates a potential neuroprotective effect but has not yet been evaluated in MD models. This study aimed to evaluate the effect of C. asiatica extract and the active compound madecassic acid on possible depressive-like behavior, inflammation, and oxidative stress in the hippocampus and serum of young rats submitted to MD in the first days of life. Rats (after the first day of birth) were separated from the mother for 3 h a day for 10 days. When adults, these animals were divided into groups and submitted to treatment for 14 days. After subjecting the animals to protocols of locomotor activity in the open field and behavioral despair in the forced swimming test, researchers then euthanized the animals. The hippocampus and serum were collected and analyzed for the inflammatory cytokines and oxidative markers. The C. asiatica extract and active compound reversed or reduced depressive-like behaviors, inflammation in the hippocampus, and oxidative stress in serum and hippocampus. These results suggest that C. asiatica and madecassic acid have potential antidepressant action, at least partially, through anti-inflammatory and antioxidant profiles.

Methamphetamine use shortens telomere length in male adults and rats

BACKGROUND

Methamphetamine (MA) use increases the risk of age-related diseases. However, it remains uncertain whether MA use exhibits accelerated biological aging, as indicated by telomere length (TL), a proposed marker of aging. Here we conducted studies in both humans and rats to investigate the association between MA use and TL.

METHODS

We recruited 125 male MA users and 66 healthy controls, aged 30-40 years. MA users were diagnosed using DSM-5 criteria and categorized into two groups: non-severe (n = 78) and severe (n = 47) MA use disorder (MUD). MA-treated conditioned place preference (CPP) rats were utilized to validate our clinical investigations. TL was assessed using real-time polymerase chain reaction.

RESULTS

At clinical levels, MA users exhibited significantly shorter leukocyte TL compared to healthy controls. Among MA users, individuals with severe MUD had significantly shorter leukocyte TL than those with non-severe MUD. Importantly, both univariate and multivariate linear regression analyses demonstrated a negative association between the severity of MA use and leukocyte TL. In a rat model of MA-induced CPP, leukocyte TL was also significantly shortened after MA administration, especially in rats with higher CPP expression or reinstatement scores.

CONCLUSION

MA use shortened TL, and the severity of MA use was negatively correlated with TL. These findings provide new insights into the pathophysiology of accelerated aging caused by MA use and may have implications for identifying biomarkers and developing novel treatment strategies for MUD.

A mitochondrial nexus in major depressive disorder: Integration with the psycho-immune-neuroendocrine network

Nervous system processes, including cognition and affective state, fundamentally rely on mitochondria. Impaired mitochondrial function is evident in major depressive disorder (MDD), reflecting cumulative detrimental influences of both extrinsic and intrinsic stressors, genetic predisposition, and mutation. Glucocorticoid 'stress' pathways converge on mitochondria; oxidative and nitrosative stresses in MDD are largely mitochondrial in origin; both initiate cascades promoting mitochondrial DNA (mtDNA) damage with disruptions to mitochondrial biogenesis and tryptophan catabolism. Mitochondrial dysfunction facilitates proinflammatory dysbiosis while directly triggering immuno-inflammatory activation via released mtDNA, mitochondrial lipids and mitochondria associated membranes (MAMs), further disrupting mitochondrial function and mitochondrial quality control, promoting the accumulation of abnormal mitochondria (confirmed in autopsy studies). Established and putative mechanisms highlight a mitochondrial nexus within the psycho-immune neuroendocrine (PINE) network implicated in MDD. Whether lowering neuronal resilience and thresholds for disease, or linking mechanistic nodes within the MDD pathogenic network, impaired mitochondrial function emerges as an important risk, a functional biomarker, providing a therapeutic target in MDD. Several treatment modalities have been demonstrated to reset mitochondrial function, which could benefit those with MDD.

Associations of depression and anxiety and adolescent telomere length

BACKGROUND

Telomere length (TL), a biomarker of cellular aging, is influenced by adverse life experiences. Although depression and anxiety are associated with shorter TL in adults, the relationship in younger ages has received little attention. We examined relationships between depression and anxiety diagnoses and symptomatology and TL in adolescence, an important developmental window for early intervention. Sex differences in relationships were also examined.

METHODS

Wave 1 survey and TL data from the Adolescent Health and Development in Context study were analyzed (N = 995). Depression and anxiety diagnosis were parent-reported measures categorized as: current diagnosis, prior diagnosis, and never diagnosed (reference category). Depressive symptoms were measured via adolescent-report using nine items from the Center for Epidemiologic Studies-Depression scale, short form. Anxiety symptoms were measured via adolescent-report using eight items from the pediatric anxiety scale obtained from the Patient-Reported Outcomes Measurement Information System. Genomic DNA was isolated from 500 μL saliva via ethanol precipitation. Genomic DNA TL was assessed using monoplexed quantitative polymerase chain reactions. Relative T/S quantities were calculated in accordance with established procedures. Covariates included sociodemographic factors (sex, age, race/ethnicity, caregiver marital status and education level, and household income), pubertal development, and season of collection. Descriptive and multivariable linear regression analyses were conducted, including an examination of sex as a moderator in the relationships between depression, anxiety, and TL.

RESULTS

In multivariable analysis, adolescents with a current depression diagnosis (b = -0.26, p < .05), but not a prior diagnosis (b =0.05, p > .05) had shorter TL than those who were never diagnosed; higher depressive symptom scores were associated with shorter TL (b = -0.12, p < .05). No significant associations were found between anxiety diagnosis and TL; however, higher anxiety symptom scores were associated with shorter TL (b = -0.14, p < .01). Sex did not significantly moderate any of the relationships between depression, anxiety and TL.

CONCLUSIONS

Depression and anxiety were associated with shorter TL in this diverse community sample of adolescents and the findings highlight the potential for impaired mental health to contribute to cellular senescence as early as adolescence. Prospective research on the long-term effect of depression and anxiety occurring earlier in the life span on TL over time is needed, including examination of potential mechanisms that may accelerate or buffer the negative effects of impaired mental health on TL.

Telomere length and chronological age across the human lifespan: A systematic review and meta-analysis of 414 study samples including 743,019 individuals

Telomere attrition is a proposed hallmark of aging. To evaluate the association of telomere length (TL) with chronological age across the human lifespan, we conducted a systematic review and meta-analysis of 414 study samples comprising 743,019 individuals aged 0-112 years. We examined both cross-sectional and longitudinal data, and evaluated the impact of various biological and methodological factors including sex, health status, tissue types, DNA extraction procedures, and TL measurement methods. The pooled corrected correlation between TL and age from cross-sectional samples was -0.19 (95%CI: -0.22 to -0.15), which weakened with increased chronological age (β = 0.003, p < 0.001). Z-score change rates of TL across the lifespan showed a gradual decrease in shortening rate until around age 50 and remained at a relatively stable rate towards the elderly period. A greater attrition rate was observed in longitudinal than cross-sectional evaluations. For TL measured in base pairs, the median change rate of TL was -23 bp/year in cross-sectional samples and -38 bp/year in longitudinal samples. Methodological factors including TL measurement methods and tissue types impacted the TL-age correlation, while sex or disease status did not. This meta-analysis revealed the non-linear shortening trend of TL across the human lifespan and provides a reference value for future studies. Results also highlight the importance of methodological considerations when using TL as an aging biomarker.

Relationship between telomere shortening and early subjective depressive symptoms and cognitive complaints in older adults

Telomere length (TL) has been reported to be associated with depression and cognitive impairment in elderly. Early detection of depression and cognitive impairment is important to delay disease progression. Therefore, we aimed to identify whether TL is associated with early subjective depressive symptoms and cognitive complaints among healthy elderly subjects. This study was a multicenter, outcome assessor-blinded, 24-week, randomized controlled trial (RCT). Measurement of questionnaire and physical activity scores and blood sample analyses were performed at baseline and after six months of follow-up in all study participants. Linear regression analyses were performed to identify whether early subjective depressive symptoms, cognitive complaints, and several blood biomarkers are associated with TL. Altogether, 137 relatively healthy elderly individuals (60-79 years old) were enrolled in this prospective RCT. We observed an approximate decrease of 0.06 and 0.11-0.14 kbps of TL per one point increase in the geriatric depression scale and cognitive complaint interview scores, respectively, at baseline and after six months of follow-up. We also found an approximate decrease of 0.08-0.09 kbps of TL per one point increase in interleukin (IL)-6 levels at baseline and after six months of follow-up. Our study showed that both early subjective depressive symptoms and cognitive complaints were associated with a relatively shorter TL in relatively healthy elderly individuals. In addition, based on our findings, we believe that IL-6 plays an important role in the relationship between shortening TL and early subjective depressive symptoms and cognitive complaints.

Psychosocial Factors and Telomere Length Among Parents and Infants of Immigrant Arab American Families

Background: Immigrant Arab American families face multiple stressors related to migration and resettlement. Telomere length (TL) is an established biomarker of aging and psychosocial stress. No published studies have concurrently examined the association between maternal and paternal psychosocial factors and infants' TL. The purpose of this study was to: (1) compare mother, father, and infant TLs; (2) explore the association of maternal and paternal psychosocial factors (acculturative stress and depressive symptoms) with maternal and paternal TL; and (3) explore the association of maternal and paternal psychosocial factors with infants' TL among Arab American immigrants. Method: Using a cross-sectional exploratory design, a sample of 52 immigrant Arab American mother-father-infant triads were recruited from community centers. Data were collected in a single home visit when the infant was 6-24 months old. Each parent completed the study questionnaires addressing their psychosocial factors (acculturative stress, and depressive symptoms), then parents and infants provided buccal cell for TL measurement. Results: Maternal TL was positively correlated to infants' TL (r = .31, p = .04) and significantly shorter (p < .001). Paternal TL was not correlated with infant TL but was significantly shorter than infant's TL (p < .001). Maternal depression was significantly correlated with mothers' TL (r = .4, p = .007). Higher levels of maternal depressive symptoms were significantly associated with shorter infant TL when controlling for background characteristics. Conclusions: Our pilot study is the first study to examine maternal and paternal psychosocial factors related to migration and infants' TL. More research is needed to advance our understanding of the effects of immigration on the intergenerational transfer of stress and trauma.

Antidepressant medication use and prostate cancer recurrence in men with depressive disorders

Purpose

Whether treating prostate cancer survivors with a depressive disorder with antidepressants can affect their cancer outcomes is unknown. We evaluated the association between antidepressant use and prostate cancer recurrence, in survivors with comorbid depressive disorders.

Methods

We conducted a longitudinal cohort study of 10,017 men with prostate cancer (stages I–II) diagnosed who also had a comorbid depressive disorder followed a maximum of 22 years, and examined rates of biochemical recurrence by antidepressant medication use. We conducted multivariable Cox models based on time-dependent antidepressant drug use status, and examined the risk of biochemical recurrence by cumulative duration of antidepressant use.

Results

Of these 10,017 survivors, 1842 (18%) experienced biochemical recurrence over 69,500 person-years of follow-up. The prostate cancer biochemical recurrence rate was greater with antidepressant non-use (31.3/1000 person-years) compared to antidepressant use (23.5/1000 person-years). In Cox proportional hazards multivariable adjusted models, non-use of antidepressants was associated with a 34% increased risk of biochemical recurrence compared to antidepressant use (HR = 1.34, 95% CI: 1.24–1.44). Longer use of antidepressants was associated with a lower biochemical recurrence risk (P trend test < 0.001).

Conclusion

Untreated depressive disorders in prostate cancer patients may be associated with an increased risk of biochemical recurrence.

Metabolic syndrome components and leukocyte telomere length in patients with major depressive disorder

OBJECTIVES

The relationship between metabolic syndrome (MetS) components and leukocyte telomere length (LTL) attrition in major depressive disorder (MDD) remains unclear.

METHODS

We recruited 70 MDD patients (mean age: 44.6 years, 60.0% female) and 51 age- and sex-matched controls (mean age: 41.2 years, 68.6% female) to examine the associations of MetS components and LTL. Five MetS components-waist circumference, systolic/diastolic blood pressure, serum levels of fasting glucose, high-density lipoprotein cholesterol (HDL-C), and triglycerides-were assessed. LTL was measured through quantitative polymerase chain reaction.

RESULTS

MDD had higher prevalence of MetS (34.3 vs. 17.6%, p=.042), low HDL-C (25.7 vs. 7.8%, p=.009) and shorter LTL (-0.038 ± 0.169 vs. 0.033 ± 0.213, p=.042). Regression analysis revealed that MDD (p=.046) and age (p=.003) associated with LTL, while a significant interaction effect of group (MDD vs. controls) × HDL-C (p=.037) was observed. Post-hoc analysis showed MDD with low HDL-C had greater LTL attrition than controls without low HDL-C (p=.020). In MDD, HDL-C dysregulation negatively correlated with LTL (p=.010); but no significance after Bonferroni correction.

CONCLUSIONS

HDL-C may be involved in accelerated ageing process regarding metabolic disturbance in MDD only. The relationship merits prospective investigations with larger sample size for clarification.

Depression, religiosity, and telomere length in the Study on Stress, Spirituality, and Health (SSSH)

Prospective studies on the association between depression and telomere length have produced mixed results and have been largely limited to European ancestry populations. We examined the associations between depression and telomere length, and the modifying influence of religion and spirituality, in four cohorts, each representing a different race/ethnic population. Relative leukocyte telomere length (RTL) was measured by a quantitative polymerase chain reaction. Our result showed that depression was not associated with RTL (percent difference: 3.0 95% CI: -3.9, 10.5; p = 0.41; p-heterogeneity across studies = 0.67) overall or in cohort-specific analyses. However, in cohort-specific analyses, there was some evidence of effect modification by the extent of religiosity or spirituality, religious congregation membership, and group prayer. Further research is needed to investigate prospective associations between depression and telomere length, and the resources of resilience including dimensions of religion and spirituality that may impact such dynamics in diverse racial/ethnic populations.

Association between Physical Activity and Telomere Length in Women with Breast Cancer: A Systematic Review

The association between physical activity and telomere length (TL) has been continuously reported. However, the interplay of physical activity and TL among women with breast cancer has not been elucidated. Thus, the purpose of this systematic review was to synthesize the evidence for the association of physical activity with TL in women with breast cancer. Systematic searches were conducted to identify quantified studies using MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, and Clinical Trials.gov. Five studies were included in this systematic review. Three of the five studies reported that physical activity has a significant relationship in delaying TL shortening, but others observed no association between physical activity and TL in breast cancer survivors. Although the heterogeneous studies acted as limitations in drawing clear conclusions, physical activity strategies show encouraging impacts in delaying TL shortening. To understand the effects of physical activity on TL shortening in breast cancer survivors, further studies are needed considering the tissue site, treatments for breast cancer, DNA extraction methods, and tools for measuring physical activity.

Telomeres are shorter and associated with number of suicide attempts in affective disorders

BACKGROUND

Shorter telomere length is a putative biomarker of accelerated aging and has been associated with affective disorders and mortality. Psychological factors and behaviors associated with telomere shortening are yet to be clarified. Here, we investigate the association between history of suicide attempts and telomere length in patients with affective disorders.

METHODS

Leucocyte telomere length was determined by quantitative real-time Polymerase Chain Reaction (qPCR) in patients with affective disorders (n = 248) including bipolar disorders type I (n = 159), type II (n = 67), major depressive disorder (n = 22), and healthy controls (n = 401). Diagnosis, duration of illness, and age at onset were assessed using the Structural Clinical Interview for DSM-IV (SCID-I). Number of lifetime suicide attempts were based on self-reports. Effect size was calculated using Cohen's d.

RESULTS

Telomere length was reduced in patients with affective disorders relative to healthy controls (d = 0.18, F = 5.26, p = 0.02). Among patients, a higher number of suicide attempts was associated with shorter telomere length (β = -0.24, t = -3.83, CI = -0.44 to -0.14, p < 0.001), also when controlling for duration of illness and age at onset (β = -.23, CI = -.42 to -.12, p = 0.001). Multiple suicide attempts were associated with telomere length reduction comparable to eight years lifespan, adjusted for demographic and clinical characteristics.

CONCLUSIONS

While longitudinal data are needed to clarify the temporal course, previous suicide attempts and related distress may accelerate telomere shortening and aging in patients with affective disorders.

Effects of Physical Exercise on Cognition and Telomere Length in Healthy Older Women

BACKGROUND

Physical exercise is an effective measure for preventing the onset of cognitive decline and has a direct influence on the aging process. The purpose of this study was to assess the effect of a 6-month physical exercise program on cognition and telomere length in adults over 65 years of age.

METHOD

Seventy-four healthy women were separated into two groups: 41 were included in the intervention group (IG) (72.70 ± 4.127 years and 8.18 ± 1.551 years of education) and 33 in the control group (CG) (71.21 ± 4.127 years and 8.42 ± 2.562). The participants included within the IG carried out three sessions of physical exercise per week for six months. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), the Stroop test and the Trail Making Test (TMT). Saliva samples were taken and analyzed and relative telomere length was calculated. Those conducting the analysis were blind to the group to which the participants had been assigned.

RESULTS

An improvement was observed in global cognitive function, in both attentional and executive functions, in the group of adults doing physical exercise as compared to the control group. Six months after the physical exercise program had finished, relative telomere length was found to have increased in the participants in the intervention group.

CONCLUSION

Physical exercise programs can lead to an improvement in both cognitive functions and telomere length.

The genetic basis of major depression

Major depressive disorder (MDD) is a common, debilitating, phenotypically heterogeneous disorder with heritability ranges from 30% to 50%. Compared to other psychiatric disorders, its high prevalence, moderate heritability, and strong polygenicity have posed major challenges for gene-mapping in MDD. Studies of common genetic variation in MDD, driven by large international collaborations such as the Psychiatric Genomics Consortium, have confirmed the highly polygenic nature of the disorder and implicated over 100 genetic risk loci to date. Rare copy number variants associated with MDD risk were also recently identified. The goal of this review is to present a broad picture of our current understanding of the epidemiology, genetic epidemiology, molecular genetics, and gene-environment interplay in MDD. Insights into the impact of genetic factors on the aetiology of this complex disorder hold great promise for improving clinical care.

Telomeres: the role of shortening and senescence in major depressive disorder and its therapeutic implications

Major depressive disorder (MDD) is one of the most prevalent and debilitating psychiatric disorders, with a large number of patients not showing an effective therapeutic response to available treatments. Several biopsychosocial factors, such as stress in childhood and throughout life, and factors related to biological aging, may increase the susceptibility to MDD development. Included in critical biological processes related to aging and underlying biological mechanisms associated with MDD is the shortening of telomeres and changes in telomerase activity. This comprehensive review discusses studies that assessed the length of telomeres or telomerase activity and function in peripheral blood cells and brain tissues of MDD individuals. Also, results from in vitro protocols and animal models of stress and depressive-like behaviors were included. We also expand our discussion to include the role of telomere biology as it relates to other relevant biological mechanisms, such as the hypothalamic-pituitary-adrenal (HPA) axis, oxidative stress, inflammation, genetics, and epigenetic changes. In the text and the discussion, conflicting results in the literature were observed, especially considering the size of telomeres in the central nervous system, on which there are different protocols with divergent results in the literature. Finally, the context of this review is considering cell signaling, transcription factors, and neurotransmission, which are involved in MDD and can be underlying to senescence, telomere shortening, and telomerase functions.

Telomere shortening in late-life depression: A potential marker of depression severity

OBJECTIVES

Telomeres are structures at the extremity of chromosomes that prevents genomic instability, and its shortening seems to be a hallmark of cellular aging. Past studies have shown contradictory results of telomere length (TL) in major depression, and are a few studies in late-life depression (LLD). This explores the association between TL as a molecular marker of aging and diagnosis of LLD, the severity of depressive symptoms, and cognitive performance in older adults.

METHODS/DESIGN

We included 78 older adults (45 with LLD and 33 nondepressed controls, according to DSM-V criteria), aged 60-90 years. TL was measured in leukocytes by a quantitative polymerase chain reaction, determining the relative ratio (T/S) between the telomere region copy number (T) and a single copy gene (S), using a relative standard curve.

RESULTS

TL was significantly shorter in the LLD compared with control participants (p = .039). Comparing groups through the severity of depressive symptoms, we found a negative correlation with the severity of depressive symptoms (Hamilton Depression Rating Scale-21, r = -0.325, p = .004) and medical burden (r = -0.271, p = .038). There was no significant correlation between TL and cognitive performance (Mattis Dementia Rating Scale, r = 0.152, p = .21).

CONCLUSIONS

We found that older adults with LLD have shorter telomere than healthy controls, especially those with a more severe depressive episode. Our findings suggest that shorter TL can be a marker of the severity of depressive episodes in older adults and indicate that these individuals may be at higher risk of age-associated adverse outcomes linked to depression.

The association of telomere length with substance use disorders: a systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

Several recent studies have investigated the relationship between telomere length and substance use disorders with inconsistent results. We aimed to assess this association and to identify moderators of the relationship.

METHODS

Systematic review and meta-analysis. Selection criteria were observational studies reporting telomere length in people with a substance use disorder compared with a control group. Studies focused solely on nicotine addiction, employing other study designs, and non-human studies were excluded. Study selection and data extraction were independently conducted by two researchers following a standardized protocol and included studies until December 2019. Standardized mean differences were used as the effect size index [d; 95% confidence interval (CI)] and random-effects models were used for the meta-analysis. Cochran's Q-statistic, I² index, visual inspection of the forest plot and a 95% prediction interval were applied to verify study heterogeneity. Subgroup analyses and meta-regressions were conducted to explore heterogeneity. Small study effects were examined using the 'funnel plot', the Egger test, Duval & Tweedie's trim-and-fill method and the precision-effect test-precision-effect estimate with standard error (PET-PEESE) method. The risk of bias and the quality of evidence were assessed.

RESULTS

Ten studies (12 analysis units with 2671 cases and 4532 controls) met the selection criteria. An overall effect size of moderate magnitude was found (d₊  = -0.63; 95% CI = -1.00 and -0.26; P = 0.0008). A potential small study effect was detected, as well as large heterogeneity between studies (Q-statistic P < 0.001, I²  = 97.3%). Selection of controls, reporting laboratory quality control procedures and total sample size significantly affected the effect size. The quality of the evidence was very low, based on risk of bias analysis and the grading of recommendations assessment, development and evaluation (GRADE) system.

CONCLUSIONS

People with substance use disorders appear to have shorter telomere length than controls; however, this finding should be interpreted with caution due to the poor quality of the evidence.

Telomere Shortening and Psychiatric Disorders: A Systematic Review

Telomeres are aging biomarkers, as they shorten while cells undergo mitosis. The aim of this study was to evaluate whether psychiatric disorders marked by psychological distress lead to alterations to telomere length (TL), corroborating the hypothesis that mental disorders might have a deeper impact on our physiology and aging than it was previously thought. A systematic search of the literature using MeSH descriptors of psychological distress ("Traumatic Stress Disorder" or "Anxiety Disorder" or "depression") and telomere length ("cellular senescence", "oxidative stress" and "telomere") was conducted on PubMed, Cochrane Library and ScienceDirect databases. A total of 56 studies (113,699 patients) measured the TL from individuals diagnosed with anxiety, depression and posttraumatic disorders and compared them with those from healthy subjects. Overall, TL negatively associates with distress-related mental disorders. The possible underlying molecular mechanisms that underly psychiatric diseases to telomere shortening include oxidative stress, inflammation and mitochondrial dysfunction linking. It is still unclear whether psychological distress is either a cause or a consequence of telomere shortening.

The association of oxytocin with major depressive disorder: role of confounding effects of antidepressants

Major depressive disorder is a genetic susceptible disease, and a psychiatric syndrome with a high rate of incidence and recurrence. Because of its complexity concerning etiology and pathogenesis, the cure rate of first-line antidepressants is low. In recent years, accumulative evidences revealed that oxytocin act as a physiological or pathological participant in a variety of complex neuropsychological activities, including major depressive disorder. Six electronic databases (Web of Science, PubMed, Scopus, Google Scholar, CNKI, and Wanfang) were employed for researching relevant publications. At last, 226 articles were extracted. The current review addresses the correlation of the oxytocin system and major depressive disorder. Besides, we summarize the mechanisms by which the oxytocin system exerts potential antidepressant effects, including regulating neuronal activity, influencing neuroplasticity and regeneration, altering neurotransmitter release, down regulating hypothalamic-pituitary-adrenal axis, anti-inflammatory, antioxidation, and genetic effects. Increasing evidence shows that oxytocin and its receptor gene may play a potential role in major depressive disorder. Future research should focus on the predictive ability of the oxytocin system as a biomarker, as well as its role in targeted prevention and early intervention of major depressive disorder.

Bi-directional association between depression and HF: An electronic health records-based cohort study

Objective:

To determine whether a bi-directional relationship exists between depression and HF within a single population of individuals receiving primary care services, using longitudinal electronic health records (EHRs).

Methods:

This retrospective cohort study utilized EHRs for adults who received primary care services within a large healthcare system in 2006. Validated EHR-based algorithms identified 10,649 people with depression (depression cohort) and 5,911 people with HF (HF cohort) between January 1, 2006 and December 31, 2018. Each person with depression or HF was matched 1:1 with an unaffected referent on age, sex, and outpatient service use. Each cohort (with their matched referents) was followed up electronically to identify newly diagnosed HF (in the depression cohort) and depression (in the HF cohort) that occurred after the index diagnosis of depression or HF, respectively. The risks of these outcomes were compared (vs. referents) using marginal Cox proportional hazard models adjusted for 16 comorbid chronic conditions.

Results:

2,024 occurrences of newly diagnosed HF were observed in the depression cohort and 944 occurrences of newly diagnosed depression were observed in the HF cohort over approximately 4–6 years of follow-up. People with depression had significantly increased risk for developing newly diagnosed HF (HR 2.08, 95% CI 1.89–2.28) and people with HF had a significantly increased risk of newly diagnosed depression (HR 1.34, 95% CI 1.17–1.54) after adjusting for all 16 comorbid chronic conditions.

Conclusion:

These results provide evidence of a bi-directional relationship between depression and HF independently of age, sex, and multimorbidity from chronic illnesses.

TERT rs2736100 and TERC rs16847897 genotypes moderate the association between internalizing mental disorders and accelerated telomere length attrition among HIV+ children and adolescents in Uganda

BACKGROUND

Internalizing mental disorders (IMDs) (depression, anxiety and post-traumatic stress disorder) have been associated with accelerated telomere length (TL) attrition; however, this association has not been investigated in the context of genetic variation that has been found to influence TL. We have previously reported an association between IMDs and accelerated TL attrition among Ugandan HIV+ children and adolescents. This study investigated the moderating effects of selected single nucleotide polymorphisms in the telomerase reverse transcriptase gene (TERT) (rs2736100, rs7726159, rs10069690 and rs2853669) and the telomerase RNA component gene (TERC) (rs12696304, rs16847897 and rs10936599) on the association between IMDs and TL, among Ugandan HIV+ children (aged 5-11 years) and adolescents (aged 12-17 years).

RESULTS

We found no significant interaction between IMDs as a group and any of the selected SNPs on TL at baseline. We observed significant interactions of IMDs with TERT rs2736100 (p = 0.007) and TERC rs16847897 (p = 0.012), respectively, on TL at 12 months.

CONCLUSIONS

TERT rs2736100 and TERC rs16847897 moderate the association between IMDs and TL among Ugandan HIV+ children and adolescents at 12 months. Understanding the nature of this association may shed light on the pathophysiological mechanisms underlying advanced cellular aging in IMDs.

The associations of hostility and defensiveness with telomere length are influenced by sex and health status

Background

Shorter telomere length (TL) may indicate premature cellular aging and increased risk for disease. While there is substantial evidence for shorter TL in individuals suffering from psychiatric disorders, data is scarce on maladaptive personality traits related to coronary artery disease (CAD). The purpose of this study was to evaluate the association of TL with hostility and defensiveness in individuals with CAD or other non-cardiovascular illnesses and whether associations were moderated by CAD status and sex.

Methods

One thousand thirty-six individuals (M_age = 65.40 ± 6.73 years) with and without CAD completed the Marlowe-Crowne Social Desirability Scale and the Cook–Medley Hostility Scale. Relative TL was measured via quantitative polymerase chain reaction of total genomic DNA samples. Analyses involved hierarchical regressions on TL, performed separately for hostility and defensiveness, controlling for pertinent sociodemographic, behavioural, and medical risk factors. Separate analyses were performed on 25 healthy participants.

Results

A hostility by sex interaction emerged (β = − .08, p = .006) in the patient groups, where greater hostility was associated with shorter TL in women only (p < .01). A Defensiveness by CAD status interaction (β = − .06, p = .049) revealed longer TL in more defensive CAD patients only (p = .06). In healthy men, shorter TL was observed in those with greater defensiveness (β = .52, p = .006) but lower hostility (β = − .43, p = .049).

Conclusion

Hostility and defensiveness are differentially associated with TL as a function of sex and health status. The implication of these results for health remains to be determined, but propose an additional pathway through which the effect of maladaptive personality traits may contribute to CV and other disease.

PBMC telomerase activity in depression and the response to electroconvulsive therapy

Telomerase, the DNA polymerase responsible for maintaining telomere length, has previously been implicated in depression and the response to antidepressant drugs. In this study, we aimed to compare telomerase activity in peripheral blood mononuclear cells between patients with severe depression recruited as part of the KEEP-WELL Trial (Ketamine for Depression Relapse Prevention Following ECT; NCT02414932) and age- and sex-matched healthy volunteers both at baseline/pre-ECT and at follow-up 1 month later for controls or in patients after a course of ECT. We found no differences in telomerase activity between patients with depression (n = 20) compared to healthy controls (n = 33) at baseline/pre-ECT, or between patients treated with ECT compared to controls at follow-up. In patients, telomerase activity was not associated with mood, as assessed by the 24-item Hamilton Rating Scale for Depression, or the duration of the current depressive episode. Additionally, we found no significant relationship between telomerase activity and exposure to recent or childhood adversity in either the patient or control groups. Overall, our results suggest that telomerase activity is not associated with depression, the therapeutic response to ECT, or exposure to adversity.

Depressive Symptoms Predict Change in Telomere Length and Mitochondrial DNA Copy Number Across Adolescence

OBJECTIVE

Several studies have found associations between a diagnosis or symptoms of major depressive disorder and markers of cellular aging and dysfunction. These investigations, however, are predominantly cross-sectional and focus on adults. In the present study, we used a prospective longitudinal design to test the cross-sectional association between depressive symptoms in adolescents and telomere length (TL) as well as mitochondrial DNA copy number (mtDNA-cn).

METHOD

A total of 121 adolescents (mean age = 11.38 years, SD = 1.03; 39% male adolescents and 61% female adolescents) were followed for approximately 2 years. At baseline and follow-up, participants provided saliva for DNA extraction, from which measures of TL and mtDNA-cn were obtained. Depressive symptoms were obtained via the Children's Depression Inventory.

RESULTS

There was no association between depressive symptoms and markers of cellular aging at baseline; however, depressive symptoms at baseline predicted higher rates of telomere erosion (β = -0.201, p = .016) and greater increases in mtDNA-cn (β = 0.190, p = .012) over the follow-up period. Markers of cellular aging at baseline did not predict subsequent changes in depressive symptoms. Furthermore, including the number of stressful life events did not alter these patterns of findings.

CONCLUSION

These results indicate that depressive symptoms precede changes in cellular aging and dysfunction, rather than the reverse.

Telomere attrition and inflammatory load in severe psychiatric disorders and in response to psychotropic medications

Individuals with severe psychiatric disorders have a reduced life expectancy compared to the general population. At the biological level, patients with these disorders present features that suggest the involvement of accelerated aging, such as increased circulating inflammatory markers and shorter telomere length (TL). To date, the role of the interplay between inflammation and telomere dynamics in the pathophysiology of severe psychiatric disorders has been scarcely investigated. In this study we measured T-lymphocytes TL with quantitative fluorescent in situ hybridization (Q-FISH) and plasma levels of inflammatory markers in a cohort comprised of 40 patients with bipolar disorder (BD), 41 with schizophrenia (SZ), 37 with major depressive disorder (MDD), and 36 non-psychiatric controls (NPC). TL was shorter in SZ and in MDD compared to NPC, while it was longer in BD (model F6, 137 = 20.128, p = 8.73 × 10-17, effect of diagnosis, F3 = 31.870; p = 1.08 × 10-15). There was no effect of the different classes of psychotropic medications, while duration of treatment with mood stabilizers was associated with longer TL (Partial correlation controlled for age and BMI: correlation coefficient = 0.451; p = 0.001). Levels of high-sensitivity C-Reactive Protein (hsCRP) were higher in SZ compared to NPC (adjusted p = 0.027), and inversely correlated with TL in the whole sample (r = -0.180; p = 0.042). Compared to NPC, patients with treatment resistant (TR) SZ had shorter TL (p = 0.001), while patients with TR MDD had higher levels of tumor necrosis factor-α (TNFα) compared to NPC (p = 0.028) and to non-TR (p = 0.039). Comorbidity with cardio-metabolic disorders did not influence the observed differences in TL, hsCRP, and TNFα among the diagnostic groups. Our study suggests that patients with severe psychiatric disorders present reduced TL and increased inflammation.

Telomere length in depression and association with therapeutic response to electroconvulsive therapy and cognitive side-effects

BACKGROUND

Electroconvulsive therapy (ECT) is the most acutely effective treatment for severe treatment-resistant depression. However, there are concerns about its cognitive side-effects and we cannot yet confidently predict who will experience these. Telomeres are DNA-protein complexes that maintain genomic integrity. In somatic cells, telomeres shorten with each cell division. Telomere length (TL) can thus provide a measure of 'biological' aging. TL appears to be reduced in depression, though results are mixed. We sought to test the following hypotheses: (1) that TL would be shorter in patients with depression compared to controls; (2) that TL would be a predictor of response to ECT; and (3) that shorter TL would predict cognitive side-effects following ECT.

METHOD

We assessed TL in whole blood DNA collected from severely depressed patients (n = 100) recruited as part of the EFFECT-Dep Trial and healthy controls (n = 80) using quantitative real-time polymerase chain reaction. Mood and selected cognitive measures, including global cognition, re-orientation time, and autobiographical memory, were obtained pre-/post-ECT and from controls.

RESULTS

Our results indicate that TL does not differ between patients with depression compared to controls. TL itself was not associated with mood ratings and did not predict the therapeutic response to ECT. Furthermore, shorter baseline TL is not a predictor of cognitive side-effects post-ECT.

CONCLUSIONS

Overall, TL assessed by PCR does not represent a useful biomarker for predicting the therapeutic outcomes or risk for selected cognitive deficits following ECT.

Inverse changes in telomere length between the blood and brain in depressive-like mice

BACKGROUND

Telomeres are nucleoprotein complexes located at the end of chromosomes. Previous studies have confirmed that telomere length is reduced in the peripheral blood of depression patients. However, studies regarding whether telomere length is altered in brain regions associated with depression are limited. It remains unclear whether the peripheral blood telomere length indicates telomere variation in the brain.

METHODS

Using quantitative PCR, we measured telomere length in five brain regions (prefrontal cortex, amygdala, nucleus accumbens, paraventricular nucleus, and hippocampus) from depressive-like mice and in peripheral blood from depressive-like mice and major depressive disorder (MDD) patients. We also examined the expression of telomerase- and alternative lengthening of telomere (ALT)-related genes in the prefrontal cortex and amygdala of depressive-like mice.

RESULTS

Telomeres were shortened in the peripheral blood of depressive-like mice and MDD patients, but were elongated in the prefrontal cortex and amygdala compared with healthy controls. We also observed that the expression of ALT-related genes increased in the prefrontal cortex and amygdala.

LIMITATIONS

The amount of human sample was limited. The mechanism of telomere lengthening in the brain of depressive-like mice was not well explained. Mice and humans have inherently different telomere and telomere maintenance systems.

CONCLUSION

These findings illustrate that the telomere length in the peripheral blood may not indicate the dynamics of telomere length in the brain. They offer a new perspective on variable telomere length in different brain regions affected in depression and provide a new basis for understanding the relationship between variable telomere length and MDD.

Altered circulatory levels of miR-128, BDNF, cortisol and shortened telomeres in patients with type 2 diabetes and depression

AIMS

Several studies have reported the role of biomarkers either in diabetes or depression. The present study is aimed at profiling the circulating levels of miR-128, brain-derived neurotrophic factor (BDNF), cortisol and telomere length in patients with type 2 diabetes with and without depression compared to individuals with normal glucose tolerance.

METHODS

Study subjects (n = 160) were recruited from an ongoing epidemiological study in southern India. Non-diabetic and diabetic individuals were diagnosed as per the World Health Organization criteria. Depression score was derived using PHQ-12 questionnaire. Real-time quantitative PCR and ELISA methodologies were used to quantify the biomarkers.

RESULTS

Circulatory levels of miR-128 and cortisol were significantly (p < 0.05) increased with decreased BDNF levels and shortened telomeres in T2DM patients with or without depression compared to NGT individuals. T2DM patients with depression had the highest levels of miR-128 and cortisol and lowest levels of BDNF and telomere length compared to other groups. Pearson correlation analysis showed miR-128 levels were negatively associated with BDNF, telomere length and HDL cholesterol and positively correlated with cortisol, depression score, poor glycemic control and insulin resistance. Regression analysis confirmed that miR-128 was significantly associated with depression score even after adjusted for several confounding factors. However, this association was lost when adjusted for cortisol or telomere length.

CONCLUSIONS

Patients with type 2 diabetes and depression exhibited increased circulatory levels of miR-128 and serum cortisol and decreased levels of BDNF and shortened telomeres. These neuroendocrine signatures were more markedly altered in those with combined diabetes and depression.

Impaired biophysical integrity of macromolecular protein pools in the uncinate circuit in late-life depression

Major depressive disorder is a common mood disorder in the elderly. Although the neuroanatomical abnormalities have been identified in patients with late-life depression (LLD), the precise biological basis of LLD remains largely unknown. The purpose of this study was to examine the biophysical integrity of macromolecular protein pools in the nodal regions of the "uncinate circuit," a component of fronto-limbic circuitry that is connected by the uncinate fasciculus and is critical in the regulation of mood and emotions, using novel magnetization transfer (MT) imaging. Twenty-four patients with LLD and 27 non-depressed healthy control subjects (HCs) of comparable age, sex, and race were recruited from the communities of the greater Chicago Area. The nodal regions of the uncinate circuit, i.e., bilateral amygdala, hippocampus, and lateral and medial orbitofrontal cortices (OFCs), were examined. Compared with HCs, patients with LLD had significantly lower magnetization transfer ratio (MTR), a measure of the biophysical integrity of macromolecular protein pools, in bilateral amygdala and hippocampus. The lower MTR was negatively correlated with the depression score. Moreover, the MTR of these regions decreased with age and positively correlated with neuropsychological performance in the LLD group but not in the HC group. These findings suggest that LLD is associated with compromised biophysical integrity of macromolecular protein pools in nodal regions of the uncinate circuit, and that major depression may accentuate age-related attenuation of the biophysical integrity of macromolecular protein pools in this circuit. These findings provide important new insights into the neurobiological mechanisms of the pathophysiology of LLD.

Childhood maltreatment, behavioral adjustment, and molecular markers of cellular aging in preschool-aged children: A cohort study

OBJECTIVE

Childhood maltreatment is a major risk factor for the development of behavioral problems and poor physical and mental health. Accelerated cellular aging, through reduced telomere length and mitochondrial dysfunction, may be a mechanism underlying these associations.

METHODS

Families with (n = 133) and without (n = 123) child welfare documentation of moderate-severe maltreatment in the past six months participated in this study. Children ranged in age from 3 to 5 years, were racially and ethnically diverse, and 91% qualified for public assistance. Structured record review and interviews were used to assess a history of maltreatment and other adversities. Telomere length and mitochondrial DNA copy number (mtDNAcn) were measured from saliva DNA using real-time PCR. Measures were repeated at a six-month follow-up assessment. Repeated measures general linear models were used to examine the effects of maltreatment and other adversities on telomere length and mtDNAcn over time.

RESULTS

Maltreatment and other adverse experiences were significant positive predictors of both telomere length and mtDNAcn over time. Internalizing and externalizing behavior problems were also both significantly associated with telomere length, but only internalizing symptoms were associated with mtDNAcn.

CONCLUSIONS

This is the first study to show that mtDNAcn is altered in children with stress and trauma, and the findings are consistent with recent studies of adults. Surprisingly, children who experienced moderate-severe levels of maltreatment in the prior six months had longer telomeres, possibly reflecting compensatory changes in response to recent trauma. Telomere length and mtDNAcn were also associated with behavioral problems, suggesting that these measures of cellular aging may be causally implicated in the pathophysiology of stress-related conditions.

Exposure to jet lag aggravates depression-like behaviors and age-related phenotypes in rats subject to chronic corticosterone

Our previous finding demonstrated that chronic corticosterone (CORT) may be involved in mediating the pathophysiology of premature aging in rats. Frequent jet lag increases the risk for many diseases, including obesity and type 2 diabetes, and is associated with the aging processes. However, the effect of jet lag on CORT-induced depression and its association with aging phenotypes remain unclear. In this study, the rats were exposed to both CORT and jet lag treatment, and the differences were analyzed and compared to rats with single CORT treatment. Our results showed that jet lag treatment aggravated CORT-induced depression-like behavior evidenced by sucrose intake test, forced swimming test, and open field test. Additionally, this treatment aggravated the shortening of telomeres, which possibly resulted in decreased telomerase activity, and downregulated the expression of telomere-binding factor 2 (TRF2) and telomerase reverse transcriptase compared to that in CORT rats, as revealed by quantitative real-time-polymerase chain reaction and western blot analysis, respectively. The shortening of telomeres may have been caused by increased oxidative stress, which was associated with the inhibition of sirtuin 3. Exposure to jet lag also aggravated the degeneration of mitochondrial functions, as shown by the decreases in the mRNA expression of COX1, ND1, and Tfam. Our findings provide physiological evidence that jet lag exposure may worsen stress-induced depression and age-related abnormalities.

An investigation of racial/ethnic and sex differences in the association between experiences of everyday discrimination and leukocyte telomere length among patients with coronary artery disease

Leukocyte telomere length (LTL) may be sensitive to psychosocial stressors such as discrimination. An inclusive examination of experiences of discrimination on LTL across racial/ethnic and sex groups is currently lacking. Baseline data were obtained from 369 White and African American patients with coronary artery disease (CAD) in the Mental Stress Ischemia Mechanisms and Prognosis Study. LTL was measured from peripheral blood leukocytes by quantitative polymerase chain reaction and calculated in kilobase pairs. Discrimination was measured using the 10-item Everyday Discrimination Scale (EDS). Responses were rated using 4-point Likert scales ranging from never = 1 to often = 4 and summed. Regression models were stratified by race/ethnicity and sex to estimate associations between discrimination and LTL. Each 10-unit increase in experiences of everyday discrimination was associated with an average of .20 fewer kilobase pairs (or 200 base pairs) among both African American women (β = -0.19; 95% CI: -0.35, -0.04; p-value: 0.02) and White women (β = -0.19; 95% CI: -0.37, -0.01; p-value: 0.04), after adjusting for basic demographic factors. Results were similar after further adjusting for behavioral, disease, and psychosocial risk factors (depression and stress). There were no significant associations between experiences of everyday discrimination and LTL for White men or African American men. Overall, experiences of discrimination were associated with shorter LTL among women and not in men. Discrimination may be a potential source of stress associated with shorter LTL among women with CAD. Future studies should explore longitudinal associations between everyday experiences of discrimination and telomere length and also with adverse cardiovascular outcomes.

Antidepressant and Antiaging Effects of Açaí (Euterpe oleracea Mart.) in Mice

Depression is a mental disorder that affects 300 million people of all ages worldwide, but fewer than half of those with the condition receive adequate treatment. In addition, the high pharmacological refractoriness (affecting 30%-50% of patients) and toxicity of some classical antidepressants support the pursuit of new therapies. People with this condition show depressed mood, loss of pleasure, high levels of oxidative stress, and accelerated biological aging (decreased telomere length and expression of the telomerase reverse transcriptase (TERT), the enzyme responsible for telomere maintenance). Because of the close relationship between depression and oxidative stress, nutraceuticals with antioxidant properties are excellent candidates for therapy. This study represents the first investigation of the possible antidepressant and antiaging effects of commercial samples of clarified açaí (Euterpe oleracea) juice (EO). This fruit is rich in antioxidants and widely consumed. In this study, mice were treated with saline or EO (10 μL/g, oral) for 4 days and then with saline or lipopolysaccharide (0.5 mg/kg, i.p.) to induce depressive-like behavior. Only four doses of EO were enough to abolish the despair-like and anhedonia behaviors and alterations observed in electromyographic measurements. The antidepression effect of EO was similar to that of imipramine and associated with antioxidant and antiaging effects (preventing lipid peroxidation and increasing TERT mRNA expression, respectively) in three major brain regions involved in depression (hippocampus, striatum, and prefrontal cortex). Additionally, EO significantly protected hippocampal cells, preventing neuronal loss associated with the depressive-like state and nitrite level increases (an indirect marker of nitric oxide production). Moreover, EO alone significantly increased TERT mRNA expression, revealing for the first time a potent antiaging action in the brain that suggests neuroprotection against long-term age-related consequences.

Telomere Length: A Potential Biomarker for the Risk and Prognosis of Stroke

Stroke is one of the leading causes of death and disability worldwide. Age is associated with increased risk of stroke, while telomere length shortening plays a pivotal role in the process of aging. Moreover, telomere length shortening is associated with many risk factors of stroke in addition to age. Accumulated evidence shows that short leukocyte telomere length is not only associated with stroke occurrence but also associated with post-stroke recovery in the elderly population. In this review, we aimed to summarize the association between leukocyte telomere length and stroke, and discuss that telomere length might serve as a potential biomarker to predict the risk and prognosis of stroke.

Cumulative lifetime stress exposure and leukocyte telomere length attrition: The unique role of stressor duration and exposure timing

BACKGROUND

Stress exposure occurring across the lifespan increases risk for disease, potentially involving telomere length shortening. Stress exposure during childhood and adulthood has been cross-sectionally linked with shorter telomere length. However, few longitudinal studies have examined telomere length attrition over time, and none have investigated how stressor duration (acute life events vs. chronic difficulties), timing (childhood vs. adulthood), and perceived severity may be uniquely related to telomere length shortening.

METHODS

To address these issues, we administered a standardized instrument for assessing cumulative lifetime stress exposure (Stress and Adversity Inventory; STRAIN) to 175 mothers of children with Autism Spectrum Disorder or neurotypical children and measured their leukocyte telomere length (LTL) at baseline and 2 years later.

RESULTS

Greater count of lifetime stressors was associated with shorter LTL at baseline and greater LTL attrition over time. When separating lifetime stressors into acute life events and chronic difficulties, only greater count of chronic difficulties significantly predicted shorter baseline LTL and greater LTL attrition. Similarly, when examining timing of stressor exposure, only greater count of chronic childhood difficulties (age < 18) significantly predicted shorter baseline LTL and greater LTL attrition over the 2-year period in mid-life. Importantly, these results were robust while controlling for stressors occurring during the interim 2-year period. Post-hoc analyses suggested that chronic difficulties occurring during earlier childhood (0-12 years) were associated with greater LTL attrition. Cumulative stressor severity predicted LTL attrition in a parallel manner, but was less consistently associated with baseline LTL.

CONCLUSIONS

These data are the first to examine the effects of different aspects of cumulative lifetime stress exposure on LTL attrition over time, suggesting that accumulated chronic difficulties during childhood may play a unique role in shaping telomere shortening in midlife.

Oxytocin administration prevents cellular aging caused by social isolation

Chronic stressors, such as chronic isolation in social mammals, can elevate glucocorticoids, which can affect cellular mechanisms of aging, including increased levels of oxidative stress and shortened telomere lengths. Recent work in the selectively social prairie vole (Microtus ochrogaster) suggests that oxytocin and social support may mitigate some of the negative consequences of social isolation, possibly by reducing glucocorticoid levels. We investigated the influences of isolation, social support, and daily oxytocin injections in female prairie voles. Glucocorticoid levels, oxidative damage, telomere length, and anhedonia, a behavioral index of depression, were measured throughout the study. We found that six weeks of chronic isolation led to increased glucocorticoid levels, oxidative damage, telomere degradation and anhedonia. However, daily oxytocin injections in isolated voles prevented these negative consequences. These findings demonstrate that chronic social isolation in female prairie voles is a potent stressor that results in depression-like behavior and accelerated cellular aging. Importantly, oxytocin can completely prevent the negative consequences of social isolation.

Chronological Aging Standard Curves of Telomere Length and Mitochondrial DNA Copy Number in Twelve Tissues of C57BL/6 Male Mouse

The changes in telomere length and mitochondrial DNA copy number (mtDNAcn) are considered to be aging markers. However, many studies have provided contradictory or only fragmentary information about changes of these markers in animal models, due to inaccurate analysis methods and a lack of objective aging standards. To establish chronological aging standards for these two markers, we analyzed telomere length and mtDNAcn in 12 tissues-leukocytes, prefrontal cortex, hippocampus, pituitary gland, adrenal gland, retina, aorta, liver, kidney, spleen, skeletal muscle, and skin-from a commonly used rodent model, C57BL/6 male mice aged 2⁻24 months. It was found that at least one of the markers changed age-dependently in all tissues. In the leukocytes, hippocampus, retina, and skeletal muscle, both markers changed age-dependently. As a practical application, the aging marker changes were analyzed after chronic immobilization stress (CIS) to see whether CIS accelerated aging or not. The degree of tissue-aging was calculated using each standard curve and found that CIS accelerated aging in a tissue-specific manner. Therefore, it is expected that researchers can use our standard curves to objectively estimate tissue-specific aging accelerating effects of experimental conditions for least 12 tissues in C57BL/6 male mice.

Leukocyte telomere length in patients with bipolar disorder: An updated meta-analysis and subgroup analysis by mood status

The purpose of the present meta-analysis was to compare leukocyte telomere length (LTL), a proposed marker for cell aging, between patients with bipolar disorder (BD) and healthy controls and explore potential moderators for the LTL difference. We searched for the major research databases up to May 2018 for studies that examined LTL in patients with BD and healthy controls. The effect sizes (ESs) of LTL differences from the included studies were pooled using a random-effects model. Furthermore, we adopted subgroup analysis to investigate whether mood status of BD patients or methods for measuring telomere length may influence such differences. We included 10 studies, with a total of 579 patients and 551 controls, in the current meta-analysis and observed significantly shorter LTL in BD patients compared to control subjects. Such differences were found in studies with patients in all mood statuses and in studies using different methods for measuring telomere length. Late-stage BD patients demonstrated more significant LTL shortening than early-stage BD patients. Our current results support the hypothesis of accelerated aging in BD patients. In the future, further properly controlled longitudinal studies are warranted to determine whether LTL changes with disease status or medication use in BD patients.

Mitochondrial DNA copy number is associated with psychosis severity and anti-psychotic treatment

Mitochondrial pathology has been implicated in the pathogenesis of psychotic disorders. A few studies have proposed reduced leukocyte mitochondrial DNA (mtDNA) copy number in schizophrenia and bipolar disorder type I, compared to healthy controls. However, it is unknown if mtDNA copy number alteration is driven by psychosis, comorbidity or treatment. Whole blood mtDNA copy number was determined in 594 psychosis patients and corrected for platelet to leukocyte count ratio (mtDNAcn_res). The dependence of mtDNAcn_res on clinical profile, metabolic comorbidity and antipsychotic drug exposure was assessed. mtDNAcn_res was reduced with age (β = −0.210, p < 0.001), use of clozapine (β = −0.110,p = 0.012) and risperidone (β = −0.109,p = 0.014), dependent on prescribed dosage (p = 0.006 and p = 0.026, respectively), and the proportion of life on treatment (p = 0.006). Clozapine (p = 0.0005) and risperidone (p = 0.0126) had a reducing effect on the mtDNA copy number also in stem cell-derived human neurons in vitro at therapeutic plasma levels. For patients not on these drugs, psychosis severity had an effect (β = −0.129, p = 0.017), similar to age (β = −0.159, p = 0.003) and LDL (β = −0.119, p = 0.029) on whole blood mtDNAcn_res. Further research is required to determine if mtDNAcn_res reflects any psychosis-intrinsic mitochondrial changes.

DNA methylation and inflammation marker profiles associated with a history of depression

Depression is a common and disabling disorder, representing a major social and economic health issue. Moreover, depression is associated with the progression of diseases with an inflammatory etiology including many inflammatory-related disorders. At the molecular level, the mechanisms by which depression might promote the onset of these diseases and associated immune-dysfunction are not well understood. In this study we assessed genome-wide patterns of DNA methylation in whole blood-derived DNA obtained from individuals with a self-reported history of depression (n = 100) and individuals without a history of depression (n = 100) using the Illumina 450K microarray. Our analysis identified six significant (Šidák corrected P < 0.05) depression-associated differentially methylated regions (DMRs); the top-ranked DMR was located in exon 1 of the LTB4R2 gene (Šidák corrected P = 1.27 × 10-14). Polygenic risk scores (PRS) for depression were generated and known biological markers of inflammation, telomere length (TL) and IL-6, were measured in DNA and serum samples, respectively. Next, we employed a systems-level approach to identify networks of co-methylated loci associated with a history of depression, in addition to depression PRS, TL and IL-6 levels. Our analysis identified one depression-associated co-methylation module (P = 0.04). Interestingly, the depression-associated module was highly enriched for pathways related to immune function and was also associated with TL and IL-6 cytokine levels. In summary, our genome-wide DNA methylation analysis of individuals with and without a self-reported history of depression identified several candidate DMRs of potential relevance to the pathogenesis of depression and its associated immune-dysfunction phenotype.

Polygenic risk score of shorter telomere length and risk of depression and anxiety in women

Prior studies have reported significant cross-sectional associations between depression or anxiety and shorter telomere lengths, but the temporality of associations is uncertain. Little is known regarding whether shorter telomere length is related to increased risk of developing depression or anxiety. In this study, using the genetic tool of polygenic risk score (PRS), we evaluated the association between genetic predisposition to shorter telomere length and the risks of lifetime clinically significant depression (defined by self-reported clinician/physician diagnosis, antidepressant use, and/or presence of severe depressive symptoms) and of clinically meaningful anxiety symptoms among 17,693 female participants of European ancestry. The weighted PRS of telomere lengths (TLs) combined the dosage of nine alleles that were significantly associated with inter-individual variation in TLs in published genome-wide association studies. Higher score of PRS, corresponding to shorter TL in the literature, was significantly associated with shorter relative TLs (p = 0.008). However, higher PRS was not associated with the lifetime risk of either depression or anxiety. Furthermore, higher PRS was not associated with long-term patterns of depressive symptom trajectories or specifically with later-life onset of depression or anxiety. In summary, this study did not observe a significant association between genetic predisposition to shorter telomere length and risk of depression and anxiety in a large sample of mid-life and older white women. However, these genetic variants jointly account for a limited proportion of interpersonal variation in leukocyte telomere length. Future studies will need to incorporate more genetic variants to improve the accuracy of predicted power, as such data become available.

Leucocyte telomere length is no molecular marker of physical frailty in late-life depression

BACKGROUND

Although average life-expectancy is still increasing worldwide, ageing processes markedly differ between individuals, which has stimulated the search for biomarkers of biological ageing.

OBJECTIVES

Firstly, to explore the cross-sectional and longitudinal association between leucocyte telomere length (LTL) as molecular marker of ageing and the physical frailty phenotype (PFP) as a clinical marker of ageing and secondly, to examine whether these associations are moderated by the presence of a depressive disorder, as depression can be considered a condition of accelerated ageing.

METHODS

Among 378 depressed older patients (according to DSM-IV criteria) and 132 non-depressed older persons participating in the Netherlands Study of Depression in Older persons, we have assessed the physical frailty phenotype and LTL. The PFP was defined according to Fried's criteria and its components were reassessed at two-year follow-up.

RESULTS

LTL was neither associated with the PFP at baseline by Spearman rank correlation tests, nor did it predict change in frailty parameters over a two-year follow-up using regression analyses adjusted for potential confounders.

CONCLUSION

LTL is not associated with frailty; neither in non-depressed nor in depressed older persons. As LTL and physical frailty appear to represent different aspects of ageing, they may complement each other in future studies.

Targeting the association between telomere length and immuno-cellular bioenergetics in female patients with Major Depressive Disorder

Major Depressive Disorder (MDD) has been associated with telomere dysfunction and alterations in mitochondrial activity, which seem to be co-regulated in human cells. To investigate this co-regulation in MDD, we assessed telomere length (TL) in peripheral blood mononuclear cells (PBMC) and selected immune cell subsets by quantitative fluorescence in situ hybridization and mitochondrial respiratory activity in PBMC by high-resolution respirometry in a study cohort of 18 MDD patients and 21 non-depressed controls. We provide initial evidence for a differential vulnerability to telomere attrition in selected adaptive immune cell populations. Here we found the highest difference in TL between depressed and control subjects for memory cytotoxic T cells. Depression was associated with reduced mitochondrial activity (mitochondrial bioenergetics), but increased mitochondrial density (mitochondrial biogenesis) in PBMC. Exploratory post-hoc analyses indicated that the changes in TL and immune cell bioenergetics were most pronounced in MDD patients who reported experiences of childhood sexual abuse. Among MDD patients, PBMC TL was as a trend positively associated with mitochondrial density and negatively associated with mitochondrial leak respiration, but not with mitochondrial activity related to biological energy production. These initial findings support the hypothesis of a co-regulation between telomeres and mitochondrial biogenesis but not mitochondrial bioenergetics among MDD patients.