Mitochondrial DNA copy number is reduced in male combat veterans with PTSD

Exploring the dissociative subtype of PTSD: The role of early-life trauma, cortisol, and inflammatory profiles

Post-traumatic stress disorder (PTSD) is a heterogeneous mental health condition, characterized by diverse symptom profiles and biological underpinnings. A dissociative subtype of PTSD has been identified, though the potential risk factors and underlying neurobiology are yet to be understood. The current study comprised Canadian Armed Forces (CAF) members and Veterans with a history of deployment, and with diagnoses of non-dissociative (n = 31) and dissociative subtypes of PTSD (n = 19), in addition to non-deployed healthy controls (n = 14). Participants completed questionnaires assessing clinical symptoms and experiences of trauma, and provided saliva and blood samples for cortisol and inflammatory marker assessments. Individuals with dissociative PTSD displayed elevated PTSD and depression symptom severity, and greater reports of specific forms of childhood trauma compared to individuals with non-dissociative PTSD and controls. Morning cortisol was elevated in both PTSD groups compared to controls, however the PTSD groups did not differ from one another. Evening cortisol concentrations were elevated in both PTSD groups compared to controls, and in the dissociative PTSD subtype compared to the non-dissociative PTSD subtype when controlling for depression symptoms. PTSD diagnostic group moderated the relationship between awakening cortisol levels and PTSD symptom severity, such that the non-dissociative PTSD group displayed a negative correlation between awakening cortisol levels and PTSD symptom severity, while no significant relation was identified in the dissociative PTSD group. C-reactive protein (CRP) levels did not differ across diagnostic groups when accounting for body mass index (BMI). However, CRP positively correlated with depressive symptoms only among individuals with dissociative PTSD. Together, examining PTSD subtypes may help inform more effective and personalized treatment strategies in the future.

L-Carnitine and Mildronate Demonstrate Divergent Protective Effects on Mitochondrial DNA Quality Control and Inflammation Following Traumatic Brain Injury

Traumatic brain injuries (TBIs) are a serious problem affecting individuals of all ages. Mitochondrial dysfunctions represent a significant form of secondary injury and may serve as a promising target for therapeutic intervention. Our research demonstrated that craniotomy, which precedes the experimental induction of trauma in mice, can cause considerable damage to mitochondrial DNA (mtDNA), disrupt the regulatory expression of angiogenesis, and increase inflammation. However, the reduction in the mtDNA copy number and glial activation occur only after a direct impact to the brain. We explored two potential therapeutic agents: the dietary supplement L-carnitine-a potential reserve source of ATP for the brain-and the cardiac drug mildronate, which inhibits L-carnitine but activates alternative compensatory pathways for the brain to adapt to metabolic disturbances. We found that L-carnitine injections could protect against mtDNA depletion by promoting mitochondrial biogenesis. However, they also appeared to aggravate inflammatory responses, likely due to changes in the composition of the gut microbiome. On the other hand, mildronate enhanced the expression of genes related to angiogenesis while also reducing local and systemic inflammation. Therefore, both compounds, despite their opposing metabolic effects, have the potential to be used in the treatment of secondary injuries caused by TBI.

Increased Rate of Unique Mitochondrial DNA Deletion Breakpoints in Young Adults With Early-Life Stress

Background

Mounting evidence suggests that mitochondria respond to psychosocial stress. Recent studies suggest mitochondrial DNA (mtDNA) deletions may be increased in some psychiatric disorders, but no studies have examined early-life stress (ELS) and mtDNA deletions. In this study, we assessed mtDNA deletions in peripheral blood mononuclear cells of medically healthy young adults with and without ELS.

Methods

Participants (n = 181; 69% female), ages 18 to 40 years, were recruited from the community. Participants with ELS (n = 108) had moderate to severe childhood maltreatment; 83 also had parental loss, and 59 had psychiatric disorders. Participants in the control group (n = 73) had no maltreatment, parental loss, or psychiatric disorders. Standardized interviews and self-report measures assessed demographic variables, stress, and mental health. mtDNA from peripheral blood mononuclear cells was amplified via long-range polymerase chain reaction; mtDNA deletions were quantified via Seq-Well, next-generation sequencing, and the Splice-Break pipeline. Linear regression models were used to assess relationships of mtDNA deletion metrics with ELS, adult stressors, psychiatric disorders, and demographics.

Results

Participants with ELS had significantly greater rates of unique mtDNA deletion breakpoints per 10,000 coverage than participants without ELS (p < .001), correcting for age, sex, and sequencing depth. Cumulative mtDNA deletion read percentage was not significantly different between groups. Psychiatric disorders and adult stressors were associated with greater unique mtDNA deletion breakpoints (ps < .05) but did not account for associations of ELS with mtDNA deletions.

Conclusions

The increased number of unique mtDNA deletion breakpoints in participants with ELS suggests that mitochondrial genomes undergo observable alterations in the context of early stress. Future studies will examine mtDNA deletions with metabolic health measures.

Association of polycystic ovary syndrome with endothelial health, cardiovascular risk, and cellular aging

OBJECTIVE

To study measures of endothelial health, cardiovascular risk, and cellular aging between patients with polycystic ovary syndrome (PCOS) and a reproductive age normative cohort.

DESIGN

Cross-sectional study.

SUBJECTS

Community-based patients with PCOS and a normative ovarian aging cohort as controls, aged ≤45 years at the time of evaluation.

EXPOSURE

Noninvasive measure of endothelial health measured by the EndoPAT reactive hyperemia index.

MAIN OUTCOME MEASURES

Reactive hyperemia index as measure of endothelial health. The secondary outcomes included Framingham score, telomere length, and mitochondrial deoxyribonucleic acid copy number from leukocyte cells.

RESULTS

Our cohort included 63 participants with PCOS and 130 non-PCOS participants. The mean age was significantly lower in the PCOS cohort (33.1; standard deviation, 4.7 years) than in the non-PCOS cohort (40.8; standard deviation, 2.9 years). In multivariable-adjusted models, we found that PCOS was significantly associated with endothelial dysfunction as both categorical (odds ratio for PCOS, 0.31; 95% confidence interval [CI], 0.10-0.97) and continuous (PCOS coefficient, -0.37; 95% CI, -0.69 to -0.05) outcomes. For secondary outcomes, PCOS status was not significantly associated with mitochondrial deoxyribonucleic acid (PCOS coefficient, -48.1; 95% CI, -175.0 to 78.9), telomere length (PCOS coefficient, 0.05; 95% CI, -0.05 to 0.15), Framingham score (PCOS coefficient, 0.002; 95% CI, -0.01 to 0.02), or metabolic syndrome (odds ratio for PCOS, 1.29; 95% CI, 0.31-5.44).

CONCLUSION

Our findings suggest that patients with PCOS have impaired endothelial function compared with non-PCOS patients, although measures of cellular aging and cardiovascular risk as measured by the Framingham score did not differ between the cohorts.

Mitochondrial dynamics and psychiatric disorders: The missing link

Elucidating the molecular mechanisms of psychopathology is crucial for optimized diagnosis and treatment. Accumulating data have underlined how mitochondrial bioenergetics affect major psychiatric disorders. However, how mitochondrial dynamics, a term addressing mitochondria quality control, including mitochondrial fission, fusion, biogenesis and mitophagy, is implicated in psychopathologies remains elusive. In this review, we summarize the existing literature on mitochondrial dynamics perturbations in psychiatric disorders/neuropsychiatric phenotypes. We include preclinical/clinical literature on mitochondrial dynamics recalibrations in anxiety, depression, post-traumatic stress disorder (PTSD), bipolar disorder and schizophrenia. We discuss alterations in mitochondrial network, morphology and shape, molecular markers of the mitochondrial dynamics machinery and mitochondrial DNA copy number (mtDNAcn) in animal models and human cohorts in brain and peripheral material. By looking for common altered mitochondrial dynamics patterns across diagnoses/phenotypes, we highlight mitophagy and biogenesis as regulators of anxiety and depression pathophysiology, respectively, as well as the fusion mediator dynamin-like 120 kDa protein (Opa1) as a molecular hub contributing to psychopathology. Finally, we comment on limitations and future directions in this novel neuropsychiatry field.

Translational bioinformatics and data science for biomarker discovery in mental health: an analytical review

Translational bioinformatics and data science play a crucial role in biomarker discovery as it enables translational research and helps to bridge the gap between the bench research and the bedside clinical applications. Thanks to newer and faster molecular profiling technologies and reducing costs, there are many opportunities for researchers to explore the molecular and physiological mechanisms of diseases. Biomarker discovery enables researchers to better characterize patients, enables early detection and intervention/prevention and predicts treatment responses. Due to increasing prevalence and rising treatment costs, mental health (MH) disorders have become an important venue for biomarker discovery with the goal of improved patient diagnostics, treatment and care. Exploration of underlying biological mechanisms is the key to the understanding of pathogenesis and pathophysiology of MH disorders. In an effort to better understand the underlying mechanisms of MH disorders, we reviewed the major accomplishments in the MH space from a bioinformatics and data science perspective, summarized existing knowledge derived from molecular and cellular data and described challenges and areas of opportunities in this space.

Circulating cell-free mitochondrial DNA levels and glucocorticoid sensitivity in a cohort of male veterans with and without combat-related PTSD

Circulating cell-free mitochondrial DNA (ccf-mtDNA) is a biomarker of cellular injury or cellular stress and is a potential novel biomarker of psychological stress and of various brain, somatic, and psychiatric disorders. No studies have yet analyzed ccf-mtDNA levels in post-traumatic stress disorder (PTSD), despite evidence of mitochondrial dysfunction in this condition. In the current study, we compared plasma ccf-mtDNA levels in combat trauma-exposed male veterans with PTSD (n = 111) with those who did not develop PTSD (n = 121) and also investigated the relationship between ccf mt-DNA levels and glucocorticoid sensitivity. In unadjusted analyses, ccf-mtDNA levels did not differ significantly between the PTSD and non-PTSD groups (t = 1.312, p = 0.191, Cohen's d = 0.172). In a sensitivity analysis excluding participants with diabetes and those using antidepressant medication and controlling for age, the PTSD group had lower ccf-mtDNA levels than did the non-PTSD group (F(1, 179) = 5.971, p = 0.016, partial η2 = 0.033). Across the entire sample, ccf-mtDNA levels were negatively correlated with post-dexamethasone adrenocorticotropic hormone (ACTH) decline (r = -0.171, p = 0.020) and cortisol decline (r = -0.149, p = 0.034) (viz., greater ACTH and cortisol suppression was associated with lower ccf-mtDNA levels) both with and without controlling for age, antidepressant status and diabetes status. Ccf-mtDNA levels were also significantly positively associated with IC50-DEX (the concentration of dexamethasone at which 50% of lysozyme activity is inhibited), a measure of lymphocyte glucocorticoid sensitivity, after controlling for age, antidepressant status, and diabetes status (β = 0.142, p = 0.038), suggesting that increased lymphocyte glucocorticoid sensitivity is associated with lower ccf-mtDNA levels. Although no overall group differences were found in unadjusted analyses, excluding subjects with diabetes and those taking antidepressants, which may affect ccf-mtDNA levels, as well as controlling for age, revealed decreased ccf-mtDNA levels in PTSD. In both adjusted and unadjusted analyses, low ccf-mtDNA levels were associated with relatively increased glucocorticoid sensitivity, often reported in PTSD, suggesting a link between mitochondrial and glucocorticoid-related abnormalities in PTSD.

Whole blood mitochondrial copy number in clinical populations with mood disorders: A meta-analysis: Blood mitochondrial copy number and mood disorders

Major depressive disorder (MDD) and bipolar disorder (BD), are globally prevalent, contributing to significant disease burden and adverse health outcomes. These mood disorders are associated with changes in many aspects of brain reward pathways, yet cellular and molecular changes in the brain are not readily available in clinical populations. Therefore, the use of biomarkers as proxies for changes in the brain are necessary. The proliferation of mitochondria in blood has emerged as a potentially useful biomarker, yet a clear consensus on how these mood disorders impact mitochondrial DNA copy number (mtDNAcn) has not been reached. To determine the current available consensus on the relationship of mood disorder diagnosis and blood mtDNcn, we performed a meta-analysis of available literature measuring this biomarker. Following PRISMA guidelines for a systematic search, 22 papers met inclusion criteria for meta-analysis (10 MDD, 10 BD, 2 both MDD and BD). We extracted demographic, disorder, and methodological information with mtDNAcn. Using the metafor package for R, calculated effect sizes were used in random effects or meta regression models for MDD and BD. Overall, our data suggest blood mtDNAcn may be a useful biomarker for mood disorders, with MDD and BD Type II associated with higher mtDNAcn, and BD Type I associated with lower mtDNAcn. Initially, we observed a trending increase in mtDNAcn in patients with MDD, which reached significance when one study with outlying demographic characteristics was excluded. Subgroup and meta-regression analysis indicated the relationship between mtDNAcn and diagnosis in patients with BD is dependent on BD type, while no relationship is detectable when BD types are mixed. Further study of blood mtDNAcn could predict downstream health outcomes or treatment responsivity in individuals with mood disorders.

Circulating Cell-Free Mitochondrial DNA and Depressive Symptoms Among Low-Active Adults Who Smoke

OBJECTIVES

Mitochondrial dysfunction is implicated in the pathophysiology of psychiatric disorders. Levels of circulating cell-free mitochondrial DNA (cf-mtDNA) are observed to be altered in depression. However, the few studies that have measured cf-mtDNA in depression have reported conflicting findings. This study examined cf-mtDNA and depressive symptoms in low-active adults who smoke.

METHODS

Participants were adults 18 to 65 years old ( N = 109; 76% female) with low baseline physical activity and depressive symptoms recruited for a smoking cessation study. Self-report measures assessed depression severity, positive and negative affect, and behavioral activation. Blood was collected and analyzed for cf-mtDNA. Relationships between depressive symptoms and cf-mtDNA were examined with correlations and linear regression.

RESULTS

Levels of cf-mtDNA were associated with categorically defined depression (Center for Epidemiologic Studies Depression Scale score >15), lower positive affect, and decreased behavioral activation ( p < .05). Relationships remained significant after adjustment for age, sex, and nicotine dependence. In a linear regression model including all depressive symptom measures as predictors, Center for Epidemiologic Studies Depression Scale group and lower positive affect remained significant.

CONCLUSIONS

This work suggests that mitochondrial changes are associated with depressive symptoms in low-active adults who smoke. Higher levels of cf-mtDNA in association with depression and with lower positive affect and decreased behavioral activation are consistent with a possible role for mitochondrial function in depressive symptoms.

Mitochondrial dysfunction as a possible trigger of neuroinflammation at post-traumatic stress disorder (PTSD)

Post-traumatic stress disorder (PTSD) is a neuropsychiatric disorder that occurs in approximately 15% of people as a result of some traumatic events. The main symptoms are re-experiencing and avoidance of everything related to this event and hyperarousal. The main component of the pathophysiology of PTSD is an imbalance in the functioning of the hypothalamic-pituitary-adrenal axis (HPA) and development of neuroinflammation. In parallel with this, mitochondrial dysfunction is observed, as in many other diseases. In this review, we focus on the question how mitochondria may be involved in the development of neuroinflammation and its maintaining at PTSD. First, we describe the differences in the operation of the neuro-endocrine system during stress versus PTSD. We then show changes in the activity/expression of mitochondrial proteins in PTSD and how they can affect the levels of hormones involved in PTSD development, as well as how mitochondrial damage/pathogen-associated molecule patterns (DAMPs/PAMPs) trigger development of inflammation. In addition, we examine the possibility of treating PTSD-related inflammation using mitochondria as a target.

Single-Nucleotide Polymorphisms in Genes Maintaining the Stability of Mitochondrial DNA Affect the Occurrence, Onset, Severity and Treatment of Major Depressive Disorder

One of the key features of major depressive disorder (MDD, depression) is increased oxidative stress manifested by elevated levels of mtROS, a hallmark of mitochondrial dysfunction, which can arise from mitochondrial DNA (mtDNA) damage. Thus, the current study explores possibility that the single-nucleotide polymorphisms (SNPs) of genes encoding the three enzymes that are thought to be implicated in the replication, repair or degradation of mtDNA, i.e., POLG, ENDOG and EXOG, have an impact on the occurrence, onset, severity and treatment of MDD. Five SNPs were selected: EXOG c.-188T > G (rs9838614), EXOG c.*627G > A (rs1065800), POLG c.-1370T > A (rs1054875), ENDOG c.-394T > C (rs2977998) and ENDOG c.-220C > T (rs2997922), while genotyping was performed on 538 DNA samples (277 cases and 261 controls) using TaqMan probes. All SNPs of EXOG and ENDOG modulated the risk of depression, but the strongest effect was observed for rs1065800, while rs9838614 and rs2977998 indicate that they might influence the severity of symptoms, and, to a lesser extent, treatment effectiveness. Although the SNP located in POLG did not affect occurrence of the disease, the result suggests that it may influence the onset and treatment outcome. These findings further support the hypothesis that mtDNA damage and impairment in its metabolism play a crucial role not only in the development, but also in the treatment of depression.

Whole blood mitochondrial copy number in clinical populations with mood disorders: a meta-analysis

Background

Major depressive disorder (MDD) and bipolar disorder (BD), are globally prevalent, contributing to significant disease burden and adverse health outcomes. These mood disorders are associated with changes in many aspects of brain reward pathways, yet cellular and molecular changes in the brain are not readily available in clinical populations. Therefore, the use of biomarkers as proxies for changes in the brain are necessary. The proliferation of mitochondria in blood has emerged as a potentially useful biomarker, yet a clear consensus on how these mood disorders impact mitochondrial DNA copy number (mtDNAcn) has not been reached.

Methods

Following PRISMA guidelines for a systematic search, 22 papers met inclusion criteria for meta-analysis (10 MDD, 10 BD, 2 both MDD and BD). We extracted demographic, disorder, and methodological information with mtDNAcn. Using the metafor package for R, calculated effect sizes were used in random effects or meta regression models for MDD and BD.

Results

Our results show a trending increase in mtDNAcn in patients with MDD, which reaches significance when one study with outlying demographic characteristics is excluded. Overall, there was no effect of BD on mtDNAcn, however, further subgroup and meta-regression analysis indicated the effects on mtDNAcn are dependent on BD type.

Conclusions

Together our data suggest whole blood/leukocyte mtDNAcn may be a useful biomarker for mood disorders, with MDD and BD Type II associated with higher mtDNAcn, and BD Type I associated with lower mtDNAcn. Further study of blood mtDNAcn could predict downstream health outcomes or treatment responsivity in individuals with mood disorders.

Sex-related difference of association of mitochondrial DNA copy number with PTSD in U.S. service members

Gender differences in the lifetime prevalence of post-traumatic stress disorder (PTSD) have been well described with rates reported as approximately 10%-12% in females and 5%-6% in males (Olff, 2017). This study examined whether the sex-related difference of mitochondrial DNA copy number (mtDNAcn), an emerging systemic index of mitochondrial biogenesis and function can serve as a potential biomarker for PTSD. Leukocyte mtDNAcn of service members with PTSD (male = 127, female = 24) or without PTSD (male = 621, female = 78) was assessed using a TaqMan assay. The results were validated by the absolute quantification of QX-200 droplet digital PCR (ddPCR). PTSD symptoms and symptom severity were assessed using the PTSD Checklist (PCL), a 17-item, DSM-based, self-report questionnaire with well-established validity and reliability. DSM-IV criteria and PTSD were determined by PCL total score. We found that mtDNAcn of female subjects with PTSD was significantly higher compared to either male or female non-PTSD controls or male subjects with PTSD (p < 0.05). There was no significant difference in mtDNAcn between males with PTSD and male/female controls without PTSD. Using in vitro cultured SH-SY5Y cells (human neuroblastoma), we demonstrated that estrogen (Estro) treatment significantly decreased mtDNAcn (P < 0.001) compared to the vehicle control. We also found that pre-treatment with either synthetic glucocorticoid dexamethasone (Dex) or Estro blocker tamoxifen (Tamox) attenuated the estrogen-induced decreases of mtDNAcn. Our data suggest that mtDNAcn may be gender-dependent in the Servicemembers with PTSD. Glucocorticoid and/or estrogen receptors may play a role in the regulation of mtDNAcn. The sex-related difference of mtDNAcn may serve as a PTSD biomarker for females.

Mitochondrial DNA as a marker for treatment-response in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a serious mental health condition thought to be mediated by a dysregulated stress response system. Stress, especially chronic stress, affects mitochondrial activity and their efficiency in duplicating their genomes. Human cells contain numerous mitochondria that harbor multiple copies of their own genome, which consist of a mixture of wild type and variant mtDNA - a condition known as mitochondrial heteroplasmy. Number of mitochondrial genomes in a cell and the degree of heteroplasmy may serve as an indicator of mitochondrial allostatic load. Changes in mtDNA copy number and the proportion of variant mtDNA may be related to mental disorders and symptom severity, suggesting an involvement of mitochondrial dysfunction also in PTSD. Therefore, we examined number and composition of mitochondrial DNA before and after six weeks of inpatient psychotherapy treatment in a cohort of 60 female PTSD patients. We extracted DNA from isolated monocytes before and after inpatient treatment and quantified cellular mtDNA using multiplex qPCR. We hypothesized that treatment would lead to changes in cellular mtDNA levels and that change in mtDNA level would be associated with PTSD symptom severity and treatment response. It could be shown that mtDNA copy number and the ratio of variant mtDNA decreased during therapy, however, this change did not correlate with treatment response. Our results suggest that inpatient treatment can reduce signs of mitochondrial allostatic load, which could have beneficial effects on mental health. The quantification of mtDNA and the determination of cellular heteroplasmy could represent valuable biomarkers for the molecular characterization of mental disorders in the future.

Psychological and biological mechanisms linking trauma with cardiovascular disease risk

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide, and experiences of psychological trauma have been associated with subsequent CVD onset. Identifying key pathways connecting trauma with CVD has the potential to inform more targeted screening and intervention efforts to offset elevated cardiovascular risk. In this narrative review, we summarize the evidence for key psychological and biological mechanisms linking experiences of trauma with CVD risk. Additionally, we describe various methodologies for measuring these mechanisms in an effort to inform future research related to potential pathways. With regard to mechanisms involving posttraumatic psychopathology, the vast majority of research on psychological distress after trauma and CVD has focused on posttraumatic stress disorder (PTSD), even though posttraumatic psychopathology can manifest in other ways as well. Substantial evidence suggests that PTSD predicts the onset of a range of cardiovascular outcomes in trauma-exposed men and women, yet more research is needed to better understand posttraumatic psychopathology more comprehensively and how it may relate to CVD. Further, dysregulation of numerous biological systems may occur after trauma and in the presence of posttraumatic psychopathology; these processes of immune system dysregulation and elevated inflammation, oxidative stress, mitochondrial dysfunction, renin-angiotensin system dysregulation, and accelerated biological aging may all contribute to subsequent cardiovascular risk, although more research on these pathways in the context of traumatic stress is needed. Given that many of these mechanisms are closely intertwined, future research using a systems biology approach may prove fruitful for elucidating how processes unfold to contribute to CVD after trauma.

Physical exercise and mitochondrial function: New therapeutic interventions for psychiatric and neurodegenerative disorders

Psychiatric and neurodegenerative diseases, including major depression disorder (MDD), bipolar disorder, and Alzheimer's disease, are a burden to society. Deficits of adult hippocampal neurogenesis (AHN) have been widely considered the main hallmark of psychiatric diseases as well as neurodegeneration. Herein, exploring applicable targets for improving hippocampal neural plasticity could provide a breakthrough for the development of new treatments. Emerging evidence indicates the broad functions of mitochondria in regulating cellular behaviors of neural stem cells, neural progenitors, and mature neurons in adulthood could offer multiple neural plasticities for behavioral modulation. Normalizing mitochondrial functions could be a new direction for neural plasticity enhancement. Exercise, a highly encouraged integrative method for preventing disease, has been indicated to be an effective pathway to improving both mitochondrial functions and AHN. Herein, the relative mechanisms of mitochondria in regulating neurogenesis and its effects in linking the effects of exercise to neurological diseases requires a systematic summary. In this review, we have assessed the relationship between mitochondrial functions and AHN to see whether mitochondria can be potential targets for treating neurological diseases. Moreover, as for one of well-established alternative therapeutic approaches, we summarized the evidence to show the underlying mechanisms of exercise to improve mitochondrial functions and AHN.

Mitochondrial health quality control: measurements and interpretation in the framework of predictive, preventive, and personalized medicine

Mitochondria are the “gatekeeper” in a wide range of cellular functions, signaling events, cell homeostasis, proliferation, and apoptosis. Consequently, mitochondrial injury is linked to systemic effects compromising multi-organ functionality. Although mitochondrial stress is common for many pathomechanisms, individual outcomes differ significantly comprising a spectrum of associated pathologies and their severity grade. Consequently, a highly ambitious task in the paradigm shift from reactive to predictive, preventive, and personalized medicine (PPPM/3PM) is to distinguish between individual disease predisposition and progression under circumstances, resulting in compromised mitochondrial health followed by mitigating measures tailored to the individualized patient profile. For the successful implementation of PPPM concepts, robust parameters are essential to quantify mitochondrial health sustainability. The current article analyses added value of Mitochondrial Health Index (MHI) and Bioenergetic Health Index (BHI) as potential systems to quantify mitochondrial health relevant for the disease development and its severity grade. Based on the pathomechanisms related to the compromised mitochondrial health and in the context of primary, secondary, and tertiary care, a broad spectrum of conditions can significantly benefit from robust quantification systems using MHI/BHI as a prototype to be further improved. Following health conditions can benefit from that: planned pregnancies (improved outcomes for mother and offspring health), suboptimal health conditions with reversible health damage, suboptimal life-style patterns and metabolic syndrome(s) predisposition, multi-factorial stress conditions, genotoxic environment, ischemic stroke of unclear aetiology, phenotypic predisposition to aggressive cancer subtypes, pathologies associated with premature aging and neuro/degeneration, acute infectious diseases such as COVID-19 pandemics, among others.

Acute and Delayed Effects of Stress Eliciting Post-Traumatic Stress-Like Disorder Differentially Alters Fecal Microbiota Composition in a Male Mouse Model

The association between the shift in fecal resident microbiome and social conflicts with long-term consequences on psychological plasticity, such as the development of post-traumatic stress disorder (PTSD), is yet to be comprehended. We developed an aggressor-exposed (Agg-E) social stress (SS) mouse model to mimic warzone-like conflicts, where random life-threatening interactions took place between naïve intruder mice and aggressive resident mice. Gradually these Agg-E mice developed distinct characteristics simulating PTSD-like aspects, whereas the control mice not exposed to Agg-E SS demonstrated distinct phenotypes. To further investigate the role of Agg-E SS on the resident microbiome, 16S rRNA gene sequencing was assayed using fecal samples collected at pre-, during, and post-SS time points. A time agonist shift in the fecal microbial composition of Agg-E mice in contrast to its controls suggested a persistent impact of Agg-E SS on resident microbiota. At the taxonomic level, Agg-E SS caused a significant shift in the time-resolved ratios of Firmicutes and Bacteroidetes abundance. Furthermore, Agg-E SS caused diverging shifts in the relative abundances of Verrucomicrobia and Actinobacteria. An in silico estimation of genomic potential identified a potentially perturbed cluster of bioenergetic networks, which became increasingly enriched with time since the termination of Agg-E SS. Supported by a growing number of studies, our results indicated the roles of the microbiome in a wide range of phenotypes that could mimic the comorbidities of PTSD, which would be directly influenced by energy deficiency. Together, the present work suggested the fecal microbiome as a potential tool to manage long-term effects of social conflicts, including the management of PTSD.

Personality traits are consistently associated with blood mitochondrial DNA copy number estimated from genome sequences in two genetic cohort studies

Background

Mitochondrial DNA copy number (mtDNAcn) in tissues and blood can be altered in conditions like diabetes and major depression and may play a role in aging and longevity. However, little is known about the association between mtDNAcn and personality traits linked to emotional states, metabolic health, and longevity. This study tests the hypothesis that blood mtDNAcn is related to personality traits and mediates the association between personality and mortality.

Methods

We assessed the big five personality domains and facets using the Revised NEO Personality Inventory (NEO-PI-R), assessed depressive symptoms with the Center for Epidemiologic Studies Depression Scale (CES-D), estimated mtDNAcn levels from whole-genome sequencing, and tracked mortality in participants from the Baltimore Longitudinal Study of Aging. Results were replicated in the SardiNIA Project.

Results

We found that mtDNAcn was negatively associated with the Neuroticism domain and its facets and positively associated with facets from the other four domains. The direction and size of the effects were replicated in the SardiNIA cohort and were robust to adjustment for potential confounders in both samples. Consistent with the Neuroticism finding, higher depressive symptoms were associated with lower mtDNAcn. Finally, mtDNAcn mediated the association between personality and mortality risk.

Conclusions

To our knowledge, this is the first study to show a replicable association between mtDNAcn and personality. Furthermore, the results support our hypothesis that mtDNAcn is a biomarker of the biological process that explains part of the association between personality and mortality.

Funding

Support for this work was provided by the Intramural Research Program of the National Institute on Aging (Z01-AG000693, Z01-AG000970, and Z01-AG000949) and the National Institute of Neurological Disorders and Stroke of the National Institutes of Health. AT was also supported by the National Institute on Aging of the National Institutes of Health Grant R01AG068093.

Genome-wide association study of mitochondrial copy number

Mitochondrial DNA copy number (mtDNAcn) variation has been associated with increased risk of several human diseases in epidemiological studies. The quantification of mtDNAcn performed with real-time PCR is currently considered the de facto standard among several techniques. However, the heterogeneity of the laboratory methods (DNA extraction, storage, processing) used could give rise to results that are difficult to compare and reproduce across different studies. Several lines of evidence suggest that mtDNAcn is influenced by nuclear and mitochondrial genetic variability, however this relation is largely unexplored. The aim of this work was to elucidate the genetic basis of mtDNAcn variation. We performed a genome-wide association study (GWAS) of mtDNAcn in 6836 subjects from the ESTHER prospective cohort, and included, as replication set, the summary statistics of a GWAS that used 295 150 participants from the UK Biobank. We observed two novel associations with mtDNAcn variation on chromosome 19 (rs117176661), and 12 (rs7136238) that reached statistical significance at the genome-wide level. A polygenic score that we called mitoscore including all known single nucleotide polymorphisms explained 1.11% of the variation of mtDNAcn (p = 5.93 × 10-7). In conclusion, we performed a GWAS on mtDNAcn, adding to the evidence of the genetic background of this trait.

Mitochondrial DNA Copy Number Adaptation as a Biological Response Derived from an Earthquake at Intrauterine Stage

An altered mitochondrial DNA copy number (mtDNAcn) at birth can be a marker of increased disease susceptibility later in life. Gestational exposure to acute stress, such as that derived from the earthquake experienced on 19 September 2017 in Mexico City, could be associated with changes in mtDNAcn at birth. Our study used data from the OBESO (Biochemical and Epigenetic Origins of Overweight and Obesity) perinatal cohort in Mexico City. We compared the mtDNAcn in the umbilical cord blood of 22 infants born before the earthquake, 24 infants whose mothers were pregnant at the time of the earthquake (exposed), and 37 who were conceived after the earthquake (post-earthquake). We quantified mtDNAcn by quantitative real-time polymerase chain reaction normalized with a nuclear gene. We used a linear model adjusted by maternal age, body mass index, socioeconomic status, perceived stress, and pregnancy comorbidities. Compared to non-exposed newborns (mean ± SD mtDNAcn: 0.740 ± 0.161), exposed and post-earthquake newborns (mtDNAcn: 0.899 ± 0.156 and 0.995 ± 0.169, respectively) had increased mtDNAcn, p = 0.001. The findings of this study point at mtDNAcn as a potential biological marker of acute stress and suggest that experiencing an earthquake during pregnancy or before gestation can have programing effects in the unborn child. Long-term follow-up of newborns to women who experience stress prenatally, particularly that derived from a natural disaster, is warranted.

PTSD as an Endothelial Disease: Insights From COVID-19

SARS-CoV-2 virus, the etiologic agent of COVID-19, has affected almost every aspect of human life, precipitating stress-related pathology in vulnerable individuals. As the prevalence rate of posttraumatic stress disorder in pandemic survivors exceeds that of the general and special populations, the virus may predispose to this disorder by directly interfering with the stress-processing pathways. The SARS-CoV-2 interactome has identified several antigens that may disrupt the blood-brain-barrier by inducing premature senescence in many cell types, including the cerebral endothelial cells. This enables the stress molecules, including angiotensin II, endothelin-1 and plasminogen activator inhibitor 1, to aberrantly activate the amygdala, hippocampus, and medial prefrontal cortex, increasing the vulnerability to stress related disorders. This is supported by observing the beneficial effects of angiotensin receptor blockers and angiotensin converting enzyme inhibitors in both posttraumatic stress disorder and SARS-CoV-2 critical illness. In this narrative review, we take a closer look at the virus-host dialog and its impact on the renin-angiotensin system, mitochondrial fitness, and brain-derived neurotrophic factor. We discuss the role of furin cleaving site, the fibrinolytic system, and Sigma-1 receptor in the pathogenesis of psychological trauma. In other words, learning from the virus, clarify the molecular underpinnings of stress related disorders, and design better therapies for these conditions. In this context, we emphasize new potential treatments, including furin and bromodomains inhibitors.

Emerging methods for and novel insights gained by absolute quantification of mitochondrial DNA copy number and its clinical applications

The past thirty years have seen a surge in interest in pathophysiological roles of mitochondria, and the accurate quantification of mitochondrial DNA copy number (mCN) in cells and tissue samples is a fundamental aspect of assessing changes in mitochondrial health and biogenesis. Quantification of mCN between studies is surprisingly variable due to a combination of physiological variability and diverse protocols being used to measure this endpoint. The advent of novel methods to quantify nucleic acids like digital polymerase chain reaction (dPCR) and high throughput sequencing offer the ability to measure absolute values of mCN. We conducted an in-depth survey of articles published between 1969 -- 2020 to create an overview of mCN values, to assess consensus values of tissue-specific mCN, and to evaluate consistency between methods of assessing mCN. We identify best practices for methods used to assess mCN, and we address the impact of using specific loci on the mitochondrial genome to determine mCN. Current data suggest that clinical measurement of mCN can provide diagnostic and prognostic value in a range of diseases and health conditions, with emphasis on cancer and cardiovascular disease, and the advent of means to measure absolute mCN should improve future clinical applications of mCN measurements.

Impaired Mitochondrial Bioenergetics Function in Pediatric Chronic Overlapping Pain Conditions with Functional Gastrointestinal Disorders

Background

Fatigue is often the primary complaint of children with functional gastrointestinal disorders (FGDI) and other chronic overlapping pain disorders (COPC). The basis for this symptom remains unknown. We evaluated mitochondrial function in the white blood cells of these patients.

Methods

This prospective Children's Wisconsin IRB approved study recruited subjects aging 10–18 years from pediatric neurogastroenterology clinics and healthy comparison subjects (HC). Environmental and oxidative stressors can damage the mitochondrial respiratory chain. The known low-grade inflammation in COPC could, therefore, impact the respiratory chain and theoretically account for the disabling fatigue so often voiced by patients. Mitochondrial energy generation can be easily measured in peripheral mononuclear cells (PMC) as a general marker by the Seahorse XF96 Extracellular Flux Analyzer. We measured 5 parameters of oxygen consumption using this methodology: basal respiration (BR), ATP linked oxygen consumption (ATP-LC), maximal oxygen consumption rate (max R), spare respiratory capacity (SRC), and extracellular acidification rate (ECAR), which reflect non-electron chain energy generation through glycolysis. In health, we expect high ATP linked respiration, high reserve capacity, low proton leak, and low non-mitochondrial respiration. In disease, the proton leak typically increases, ATP demand increases, and there is decreased reserve capacity with increased non-mitochondrial respiration. Findings and clinical data were compared to healthy control subjects using a Mann–Whitney test for skewed variables, Fisher's exact test for dichotomous variables, and regression tree for association with functional outcome (functional disability inventory, FDI).

Results

19 HC and 31 COPC showed no statistically significant difference in age. FGID, orthostatic intolerance, migraine, sleep disturbance, and chronic fatigue were present in the majority of COPC subjects. BR, ECAR, and ATP-LC rates were lower in the COPC group. The low BR and ATP-LC suggest that mitochondria are stressed with decreased ability to produce ATP. Tree analysis selected SRC as the best predictor of functional disability: patients with SRC >150 had a greater FDI (more disability) compared to patients with SRC <=150, p-value = 0.021.

Conclusion

Subjects with COPC have reduced mitochondrial capacity to produce ATP. Predisposing genetic factors or reversible acquired changes may be responsible. A higher SRC best predicts disability. Since a higher SRC is typically associated with more mitochondrial reserve, the SRC may indicate an underutilized available energy supply related to inactivity, or a “brake” on mitochondrial function. Prospective longitudinal studies can likely discern whether these findings represent deconditioning, true mitochondrial dysfunction, or both.

Cerebellar and multi-system metabolic reprogramming associated with trauma exposure and post-traumatic stress disorder (PTSD)-like behavior in mice

Mitochondrial metabolism is increasingly implicated in psychopathologies and mood disorders, including post-traumatic stress disorder (PTSD). We recently reported that mice exposed to a novel paradigm for the induction of PTSD-like behavior displayed reduced mitochondrial electron transport chain (mtETC) complex activity as well as decreased multi-system fatty acid oxidation (FAO) flux. Based on these results, we hypothesized that stressed and PTSD-like animals would display evidence of metabolic reprogramming in both cerebellum and plasma consistent with increased energetic demand, mitochondrial metabolic reprogramming, and increased oxidative stress. We performed targeted metabolomics in both cerebellar tissue and plasma, as well as untargeted nuclear magnetic resonance (NMR) spectroscopy in the cerebellum of 6 PTSD-like and 7 resilient male mice as well as 7 trauma-naïve controls. We identified numerous differences in amino acids and tricarboxylic acid (TCA) cycle metabolite concentrations in the cerebellum and plasma consistent with altered mitochondrial energy metabolism in trauma exposed and PTSD-like animals. Pathway analysis identified metabolic pathways with significant metabolic pathway shifts associated with trauma exposure, including the tricarboxylic acid cycle, pyruvate, and branched-chain amino acid metabolism in both cerebellar tissue and plasma. Altered glutamine and glutamate metabolism, and arginine biosynthesis was evident uniquely in cerebellar tissue, while ketone body levels were modified in plasma. Importantly, we also identified several cerebellar metabolites (e.g. choline, adenosine diphosphate, beta-alanine, taurine, and myo-inositol) that were sufficient to discriminate PTSD-like from resilient animals. This multilevel analysis provides a comprehensive understanding of local and systemic metabolite fingerprints associated with PTSD-like behavior, and subsequently altered brain bioenergetics. Notably, several transformed metabolic pathways observed in the cerebellum were also reflected in plasma, connecting central and peripheral biosignatures of PTSD-like behavior. These preliminary findings could direct further mechanistic studies and offer insights into potential metabolic interventions, either pharmacological or dietary, to improve PTSD resilience.

Some Molecular and Cellular Stress Mechanisms Associated with Neurodegenerative Diseases and Atherosclerosis

Chronic stress is a combination of nonspecific adaptive reactions of the body to the influence of various adverse stress factors which disrupt its homeostasis, and it is also a corresponding state of the organism's nervous system (or the body in general). We hypothesized that chronic stress may be one of the causes occurence of several molecular and cellular types of stress. We analyzed literary sources and considered most of these types of stress in our review article. We examined genes and mutations of nuclear and mitochondrial genomes and also molecular variants which lead to various types of stress. The end result of chronic stress can be metabolic disturbance in humans and animals, leading to accumulation of reactive oxygen species (ROS), oxidative stress, energy deficiency in cells (due to a decrease in ATP synthesis) and mitochondrial dysfunction. These changes can last for the lifetime and lead to severe pathologies, including neurodegenerative diseases and atherosclerosis. The analysis of literature allowed us to conclude that under the influence of chronic stress, metabolism in the human body can be disrupted, mutations of the mitochondrial and nuclear genome and dysfunction of cells and their compartments can occur. As a result of these processes, oxidative, genotoxic, and cellular stress can occur. Therefore, chronic stress can be one of the causes forthe occurrence and development of neurodegenerative diseases and atherosclerosis. In particular, chronic stress can play a large role in the occurrence and development of oxidative, genotoxic, and cellular types of stress.

DNA methylation and psychotherapy response in trauma-exposed men with appetitive aggression

Exposure to violence can lead to appetitive aggression (AA), the positive feeling and fascination associated with violence, and posttraumatic stress disorder (PTSD), characterised by hyperarousal, reexperience and feelings of ongoing threat. Psychotherapeutic interventions may act via DNA methylation, an environmentally sensitive epigenetic mechanism that can influence gene expression. We investigated epigenetic signatures of psychotherapy for PTSD and AA symptoms in South African men with chronic trauma exposure. Participants were assigned to one of three groups: narrative exposure therapy for forensic offender rehabilitation (FORNET), cognitive behavioural therapy or waiting list control (n = 9-10/group). Participants provided saliva and completed the Appetitive Aggression Scale and PTSD Symptom Severity Index at baseline, 8-month and 16-month follow-up. The relationship, over time, between methylation in 22 gene promoter region sites, symptom scores, and treatment was assessed using linear mixed models. Compared to baseline, PTSD and AA symptom severity were significantly reduced at 8 and 16 months, respectively, in the FORNET group. Increased methylation of genes implicated in dopaminergic neurotransmission (NR4A2) and synaptic plasticity (AUTS2) was associated with reduced PTSD symptom severity in participants receiving FORNET. Analyses across participants revealed a proportional relationship between AA and methylation of TFAM, a gene involved in mitochondrial biosynthesis.

Severe life stress, mitochondrial dysfunction, and depressive behavior: A pathophysiological and therapeutic perspective

Mitochondria are responsible for providing our cells with energy, as well as regulating oxidative stress and apoptosis, and considerable evidence demonstrates that mitochondria-related alterations are prevalent during chronic stress and depression. Here, we discuss how chronic stress may induce depressive behavior by potentiating mitochondrial allostatic load, which ultimately decreases energy production, elevates the generation of harmful reactive oxygen species, damages mitochondrial DNA and increases membrane permeability and pro-apoptotic factor release. We also discuss how mitochondrial insults can exacerbate the immune response, contributing to depressive symptomology. Furthermore, we illustrate how depression symptoms are associated with specific mitochondrial defects, and how targeting of these defects with pharmacological agents may be a promising avenue for the development of novel, more efficacious antidepressants. In summary, this review supports the notion that severe psychosocial stress induces mitochondrial dysfunction, thereby increasing the vulnerability to developing depressive symptoms.

Novel Pharmacological Targets for Combat PTSD-Metabolism, Inflammation, The Gut Microbiome, and Mitochondrial Dysfunction

INTRODUCTION

Current pharmacological treatments of post-traumatic stress disorder (PTSD) have limited efficacy. Although the diagnosis is based on psychopathological criteria, it is frequently accompanied by somatic comorbidities and perhaps "accelerated biological aging," suggesting widespread physical concomitants. Such physiological comorbidities may affect core PTSD symptoms but are rarely the focus of therapeutic trials.

METHODS

To elucidate the potential involvement of metabolism, inflammation, and mitochondrial function in PTSD, we integrate findings and mechanistic models from the DOD-sponsored "Systems Biology of PTSD Study" with previous data on these topics.

RESULTS

Data implicate inter-linked dysregulations in metabolism, inflammation, mitochondrial function, and perhaps the gut microbiome in PTSD. Several inadequately tested targets of pharmacological intervention are proposed, including insulin sensitizers, lipid regulators, anti-inflammatories, and mitochondrial biogenesis modulators.

CONCLUSIONS

Systemic pathologies that are intricately involved in brain functioning and behavior may not only contribute to somatic comorbidities in PTSD, but may represent novel targets for treating core psychiatric symptoms.

Leukocyte mitochondrial DNA copy number in schizophrenia

OBJECTIVE

Schizophrenia is a complex neuropsychiatric disorder with significant genetic predisposition. In a subset of schizophrenia patients, mitochondrial dysfunction could be explained by the genomic defects like mitochondrial DNA Copy Number Variations, which are considered as a sensitive index of cellular oxidative stress. Given the high energy demands for neuronal functions, altered Mitochondrial DNA copy number (mtDNAcn) and consequent impaired mitochondrial physiology would significantly influence schizophrenia pathogenesis. In this context, we have made an attempt to study mitochondrial dysfunction in schizophrenia by assessing mtDNAcn in antipsychotic-naïve/free schizophrenia patients.

METHOD

mtDNAcn was measured in 90 antipsychotic-naïve / free schizophrenia (SCZ) patients and 147 Healthy Controls (HC). The relative mtDNAcn was determined by quantitative real-time polymerase chain reaction (qPCR) using TaqMan® multiplex assay method.

RESULT

A statistically significant difference between groups [t = 5.22, P < 0.001] was observed, with significantly lower mtDNAcn in SCZ compared to HC. The group differences persisted even after controlling for age and sex [F (4, 232) = 22.68, P < 0.001, η2 = 0.09].

CONCLUSION

Lower mtDNAcn in SCZ compared to HC suggests that mtDNAcn may hold potential to serve as an important proxy marker of mitochondrial function in antipsychotic-naïve/free SCZ patients.

Neurophysiology and Psychopathology Underlying PTSD and Recent Insights into the PTSD Therapies-A Comprehensive Review

Post-traumatic stress disorder (PTSD) is a well-known psychiatric disorder that affects millions of people worldwide. Pharmacodynamic and cognitive-behavioral therapies (CBT) have been used to treat patients with PTSD. However, it remains unclear whether there are concurrent changes in psychopathological and neurophysiological factors associated with PTSD patients. Past reports described those PTSD patients with efficient fatty acid metabolism, neurogenesis, mitochondrial energy balance could improve ability to cope against the conditioned fear responses and traumatic memories. Furthermore, cognitive, behavioral, cellular, and molecular evidence can be combined to create personalized therapies for PTSD sufferers either with or without comorbidities such as depression or memory impairment. Unfortunately, there is still evidence lacking to establish a full understanding of the underlying neurophysiological and psychopathological aspects associated with PTSD. This review has extensively discussed the single nucleotide polymorphism (SNPs) of genetic factors to cause PTSD, the implications of inflammation, neurotransmitter genomics, metabolic alterations, neuroendocrine disturbance (hypothalamus-pituitary-adrenal (HPA) axis), mitochondrial dynamics, neurogenesis, and premature aging related to PTSD-induced psychopathology and neurophysiology. In addition, the review delineated the importance of CBT and several pharmacodynamic therapies to mitigate symptomatology of PTSD.

Cerebellar mitochondrial dysfunction and concomitant multi-system fatty acid oxidation defects are sufficient to discriminate PTSD-like and resilient male mice

The impact of trauma on mental health is complex with poorly understood underlying mechanisms. Mitochondrial dysfunction is increasingly implicated in psychopathologies and mood disorders, including post-traumatic stress disorder (PTSD). We hypothesized that defects in mitochondrial energy metabolism in the cerebellum, an emerging region of interest in the pathobiology of mood disorders, would be associated with PTSD-like symptomatology, and that PTSD-like symptomatology would correlate with the activities of the mitochondrial electron transport chain (mtETC) and fatty acid oxidation (FAO) pathways. We assayed mitochondrial energy metabolism and fatty acid profiling using targeted metabolomics in mice exposed to a recently developed paradigm for PTSD-induction. 48 wild type male FVB.129P2 mice were exposed to a trauma, and PTSD-like and resilient animals were identified using behavioral profiling. Mice displaying PTSD-like symptomatology displayed reduced mtETC complex activities in the cerebellum, and cerebellar mtETC complex activity negatively correlated with PTSD-like symptomatology. PTSD-like animals also displayed fatty acid profiles consistent with FAO dysfunction in both cerebellum and plasma. Machine learning analysis of all biochemical measures in this cohort of animals also identified plasma acetylcarnitine, along with reduced activity of cerebellar complex I and IV as well as succinate:cytochrome c oxidoreductase as state predictive discriminators of PTSD-symptomatology. Our data also suggest that trauma-induced impaired mtETC function in the cerebellum and concomitant impaired multi-system fatty acid oxidation are candidate drivers of PTSD-like behavior in mice. These bioenergetic and metabolic changes may offer an informative window into the underlying biology and highlight novel potential targets for diagnostics and therapeutic interventions in PTSD.

Molecular markers of neuroendocrine function and mitochondrial biogenesis associated with early life stress

OBJECTIVE

Glucocorticoid receptor gene (NR3C1) promoter methylation influences cellular expression of the glucocorticoid receptor and is a proposed mechanism by which early life stress impacts neuroendocrine function. Mitochondria are sensitive and responsive to neuroendocrine stress signaling through the glucocorticoid receptor, and recent evidence with this sample and others shows that mitochondrial DNA copy number (mtDNAcn) is increased in adults with a history of early stress. No prior work has examined the role of NR3C1 methylation in the association between early life stress and mtDNAcn alterations.

METHODS

Adult participants (n = 290) completed diagnostic interviews and questionnaires characterizing early stress and lifetime psychiatric symptoms. Medical conditions, active substance abuse, and prescription medications other than oral contraceptives were exclusionary. Subjects with a history of lifetime bipolar, obsessive-compulsive, or psychotic disorders were excluded; individuals with other forms of major psychopathology were included. Whole blood mtDNAcn was measured using qPCR; NR3C1 methylation was measured via pyrosequencing. Multiple regression and bootstrapping procedures tested NR3C1 methylation as a mediator of effects of early stress on mtDNAcn.

RESULTS

The positive association between early adversity and mtDNAcn (p = .02) was mediated by negative associations of early adversity with NR3C1 methylation (p = .02) and NR3C1 methylation with mtDNAcn (p < .001). The indirect effect involving early adversity, NR3C1 methylation, and mtDNAcn was significant (95 % CI [.002, .030]).

CONCLUSIONS

NR3C1 methylation significantly mediates the association between early stress and mtDNAcn, suggesting that glucocorticoid receptor signaling may be a mechanistic pathway underlying mtDNAcn alterations of interest for future longitudinal work.

Affective dynamics among veterans: Associations with distress tolerance and posttraumatic stress symptoms

We tested a dynamic structural equation model (DSEM; Asparouhov, Hamaker, & Muthén, 2018) of positive and negative affect in 254 veterans with approximately 1.5 years of experience sampling data. The analysis provided estimates of several aspects of veteran's emotional experience including "trait" positive and negative affect (i.e., mean levels), inertia (i.e., tendency for emotions to self-perpetuate), innovation variance (conceptualized as lability, reactivity, or exposure to stressors), and cross-lagged associations between positive and negative affect. Veterans with higher trait negative affect had more negative affect inertia and innovation variance. This suggests a pattern whereby the veteran has more negative reactions, and negative emotions, in turn, tend to maintain themselves, contributing to higher trait negative affect. In contrast, veterans with higher trait positive affect exhibited more positive affect innovation variance (e.g., positive reactivity). Although veterans showed some consistency in dynamics across emotions (e.g., positive and negative reactivity were positively correlated), trait positive and negative affect were not significantly associated. Veterans with higher posttraumatic stress symptoms (PTSS) at baseline exhibited higher reactivity to negative events, less positive affect, and more negative affect during the follow-up. Veterans with higher distress tolerance reported not only lower PTSS but also a more adaptive pattern of affective experience characterized by lower inertia and reactivity in negative affect and more positive lagged associations between negative affect and subsequent positive affect. The results demonstrated that distress tolerance and PTSS in veterans were associated with dynamics of positive and negative emotion over time, suggesting specific differences in affect regulation processes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Rate of dyslipidemia higher among women living with HIV: A comparison of metabolic and cardiovascular health in a cohort to study aging in HIV

OBJECTIVES

Combination antiretroviral therapy has largely restored the lifespan of persons living with HIV. Data suggest early comorbidities of aging in this population. Past studies focused on men; limited data exist regarding the prevalence of dyslipidaemia in women living with HIV (WLWH). We investigated the prevalence of cardiometabolic abnormalities among WLWH and HIV-negative women in the Children and Women: Antiretrovirals and Markers of Aging (CARMA) cohort, and their relationships to cellular aging markers.

METHODS

We conducted a cross-sectional analysis of nonpregnant female patients (156 WLWH and 133 HIV-negative controls, aged 12-69 years) enrolled in CARMA between 2013 and 2017. The Framingham risk score (FRS) and the prevalences of hypertension, diabetes, metabolic syndrome and dyslipideamia were determined using self-report, anthropometrics, chart review and laboratory data. Cellular aging was determined by assessing leukocyte telomere length and blood mitochondrial DNA content. Diagnoses were based on current Canadian guidelines and definitions.

RESULTS

HIV-infected status was associated with dyslipidaemia [odds ratio (OR) 2.89; 95% confidence interval (CI) 1.69-5.01], but not diabetes, higher FRS, hypertension or metabolic syndrome. The median age was 43.5 [interquartile range (IQR) 36.8-50.9] years in WLWH and 46.2 (IQR 30.3-54.9) years in HIV-negative controls. WLWH were less likely to be menopausal or use alcohol, and more often had hepatitis C virus infection or a current or past smoking history. Lower mitochondrial DNA content was associated with metabolic syndrome; no other associations were noted between cardiometabolic abnormalities and markers of cellular aging.

CONCLUSIONS

Despite their relatively young age, almost two-thirds of WLWH had dyslipidaemia, a significantly greater proportion than in controls. Strategies to address dyslipidaemia and decrease smoking rates may improve long-term outcomes among WLWH.

No Evidence of Persistence or Inheritance of Mitochondrial DNA Copy Number in Holocaust Survivors and Their Descendants

Mitochondrial DNA copy number has been previously shown to be elevated with severe and chronic stress, as well as stress-related pathology like Major Depressive Disorder (MDD) and post-traumatic stress disorder (PTSD). While experimental data point to likely recovery of mtDNA copy number changes after the stressful event, time needed for full recovery and whether it can be achieved are still unknown. Further, while it has been shown that stress-related mtDNA elevation affects multiple tissues, its specific consequences for oogenesis and maternal inheritance of mtDNA has never been explored. In this study, we used qPCR to quantify mtDNA copy number in 15 Holocaust survivors and 102 of their second- and third-generation descendants from the Czech Republic, many of whom suffer from PTSD, and compared them to controls in the respective generations. We found no significant difference in mtDNA copy number in the Holocaust survivors compared to controls, whether they have PTSD or not, and no significant elevation in descendants of female Holocaust survivors as compared to descendants of male survivors or controls. Our results showed no evidence of persistence or inheritance of mtDNA changes in Holocaust survivors, though that does not rule out effects in other tissues or mitigating mechanism for such changes.

Stress and Psychiatric Disorders: The Role of Mitochondria

In seeking to understand mental health and disease, it is fundamental to identify the biological substrates that draw together the experiences and physiological processes that underlie observed psychological changes. Mitochondria are subcellular organelles best known for their central role in energetics, producing adenosine triphosphate to power most cellular processes. Converging lines of evidence indicate that mitochondria play a key role in the biological embedding of adversity. Preclinical research documents the effects of stress exposure on mitochondrial structure and function, and recent human research suggests alterations constituting recalibrations, both adaptive and nonadaptive. Current research suggests dynamic relationships among stress exposure, neuroendocrine signaling, inflammation, and mitochondrial function. These complex relationships are implicated in disease risk, and their elucidation may inform prevention and treatment of stress- and trauma-related disorders. We review and evaluate the evidence for mitochondrial dysfunction as a consequence of stress exposure and as a contributing factor to psychiatric disease.

Mitochondrial DNA copy number, damage, repair and degradation in depressive disorder

Objectives: We aimed to explore mitochondrial DNA (mtDNA) copy number, damage, repair and degradation in peripheral blood mononuclear cells (PBMCs) of patients with depression and to compare the results with healthy subjects.Methods: Total genomic DNA was isolated from PBMCs of 25 depressed and 60 healthy subjects before, immediately after, and 3 h after the exposure to H₂O₂. Evaluation of mtDNA copy number was performed using real-time PCR and 2-ΔCt methods. Semi-long run real-time PCR was used to estimate the number of mtDNA lesions.Results: Baseline mtDNA copy number did not differ in cells of healthy and depressed subjects; however, it was negatively correlated with the severity of the episode. After a 10-min challenge with hydrogen peroxide (H₂O₂), depressed patients' PBMCs exhibited slower changes of the copy number, indicating a lower efficiency of mtDNA degradation compared to controls. Moreover, a significantly higher number of mtDNA lesions was found in depressed patients at the baseline as well as at other experimental time points. mtDNA lesions were also elevated in depressed patient cells immediately after H₂O₂ exposure. Induction of oxidative stress had no significant influence on the cells of controls.Conclusions: We are the first to show that impairment in repair and degradation of mtDNA may be involved in the pathophysiology of depression.

Investigation of mitochondrial DNA copy number in patients with major depressive disorder

Mitochondrial dysfunction is implicated in the pathophysiology of major depressive disorder (MDD). This dysfunction can be indirectly assessed using the mitochondrial DNA (mtDNA) copy number. A total of 118 patients with MDD and 116 age- and sex-matched control subjects were recruited for this study, and mtDNA copy numbers were measured in peripheral blood cells. This study also examined the potential variables that might impact mtDNA copy number in MDD, including age and clinical features. Additionally, epigenetic control of mtDNA copy number was examined by assessing DNA methylation ratios in the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) promoter in nuclear DNA and the displacement loop (D-loop) region of mtDNA. The present results showed that patients with MDD had a higher mtDNA copy number and a decreased DNA methylation status in the PGC1α promoter. mtDNA copy numbers were negatively associated with an age, psychomotor agitation, and somatic symptoms in MDD. These results suggest that the alterations in mitochondrial function and epigenetic change of PGC1α may be relevant to the pathophysiology of MDD.

Mechanistic inferences on metabolic dysfunction in posttraumatic stress disorder from an integrated model and multiomic analysis: role of glucocorticoid receptor sensitivity

Posttraumatic stress disorder (PTSD) is associated with neuroendocrine alterations and metabolic abnormalities; however, how metabolism is affected by neuroendocrine disturbances is unclear. The data from combat-exposed veterans with PTSD show increased glycolysis to lactate flux, reduced TCA cycle flux, impaired amino acid and lipid metabolism, insulin resistance, inflammation, and hypersensitive hypothalamic-pituitary-adrenal (HPA) axis. To analyze whether the co-occurrence of multiple metabolic abnormalities is independent or arises from an underlying regulatory defect, we employed a systems biological approach using an integrated mathematical model and multiomic analysis. The models for hepatic metabolism, HPA axis, inflammation, and regulatory signaling were integrated to perform metabolic control analysis (MCA) with respect to the observations from our clinical data. We combined the metabolomics, neuroendocrine, clinical laboratory, and cytokine data from combat-exposed veterans with and without PTSD to characterize the differences in regulatory effects. MCA revealed mechanistic association of the HPA axis and inflammation with metabolic dysfunction consistent with PTSD. This was supported by the data using correlational and causal analysis that revealed significant associations between cortisol suppression, high-sensitivity C-reactive protein, homeostatic model assessment of insulin resistance, γ-glutamyltransferase, hypoxanthine, and several metabolites. Causal mediation analysis indicates that the effects of enhanced glucocorticoid receptor sensitivity (GRS) on glycolytic pathway, gluconeogenic and branched-chain amino acids, triglycerides, and hepatic function are jointly mediated by inflammation, insulin resistance, oxidative stress, and energy deficit. Our analysis suggests that the interventions to normalize GRS and inflammation may help to manage features of metabolic dysfunction in PTSD.

Accelerated aging in serious mental disorders

PURPOSE OF REVIEW

Clinical, epidemiological, and biological evidence raises the possibility that serious mental disorders (SMDs) are associated with accelerated biological aging. To the extent this is true; SMDs should not simply be considered in terms of mental illness or brain dysfunction, but also as 'whole body' and multisystem illnesses, or else as conditions with significant somatic concomitants.

RECENT FINDINGS

The concept of accelerated biological aging in SMDs is supported by reports of accelerated changes in certain biomarkers normally associated with the aging process.

SUMMARY

We define and discuss several proposed biological aging markers that have been examined in SMDs, we review the most recent findings, and we conclude with opinions regarding the merits and meanings of these markers, their usefulness in understanding and treating SMDs, and remaining questions and future directions in this area of research.

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.

Accelerating research on biological aging and mental health: Current challenges and future directions

Aging is associated with complex biological changes that can be accelerated, slowed, or even temporarily reversed by biological and non-biological factors. This article focuses on the link between biological aging, psychological stressors, and mental illness. Rather than comprehensively reviewing this rapidly expanding field, we highlight challenges in this area of research and propose potential strategies to accelerate progress in this field. This effort requires the interaction of scientists across disciplines - including biology, psychiatry, psychology, and epidemiology; and across levels of analysis that emphasize different outcome measures - functional capacity, physiological, cellular, and molecular. Dialogues across disciplines and levels of analysis naturally lead to new opportunities for discovery but also to stimulating challenges. Some important challenges consist of 1) establishing the best objective and predictive biological age indicators or combinations of indicators, 2) identifying the basis for inter-individual differences in the rate of biological aging, and 3) examining to what extent interventions can delay, halt or temporarily reverse aging trajectories. Discovering how psychological states influence biological aging, and vice versa, has the potential to create novel and exciting opportunities for healthcare and possibly yield insights into the fundamental mechanisms that drive human aging.

Maternal corticosterone in the mouse alters oxidative stress markers, antioxidant function and mitochondrial content in placentas of female fetuses

KEY POINTS

Maternal exposure to the stress hormone corticosterone is known to programme a range of sex specific disease outcomes in offspring. Sex differences in placental adaptations are thought to mediate these processes. Placental oxidative stress is implicated in a range of pregnancy disorders but the role of placental oxidative stress in sex specific disease outcomes following prenatal corticosterone exposure is unknown. This study demonstrates that maternal corticosterone reduced placental hydrogen peroxide and 8-hydroxy-2'-deoxyguanosine concentrations but increased protein carbonyl content and advanced glycation end product concentrations in placentas of female fetuses but not male fetuses. These results highlight that placentas of female fetuses respond differently to maternal corticosterone exposure, with oxidative stress a major finding in placentas of female fetuses.

ABSTRACT

Maternal exposure to glucocorticoids during pregnancy increases offspring risk of developing a range of sex specific disease phenotypes. These sex specific disease outcomes are thought to be in part mediated by different placental adaptations in males and females. The placenta is a highly metabolic organ which is vulnerable to the effects of oxidative stress. In other tissues, males and females have been shown to respond differently to the pro-oxidant effects of glucocorticoids. This study therefore used a well characterized animal model of maternal corticosterone exposure to investigate sex specific alterations in reactive oxygen species production, antioxidant concentrations and mitochondrial properties that might contribute to sex differences in placental outcomes. C57BL/6 mice were implanted with osmotic minipumps containing corticosterone (33 μg kg^-1  h^-1 ) at embryonic day (E) 12.5 and placentas collected at E14.5 for analysis. Corticosterone exposure reduced placental hydrogen peroxide (H₂ O₂ ) and 8-hydroxy-2'-deoxyguanosine concentrations but increased protein carbonyl content and advanced glycation end product concentrations in placentas of female fetuses but not male fetuses. This dysregulation of different markers of oxidative stress may be due to increased placental activity of thioredoxin reductase in female but not male fetuses. Corticosterone reduced placental mitochondrial content but increased protein expression of the autophagosome cargo protein p62. This study demonstrates that placentas of female fetuses respond differently to maternal corticosterone exposure and highlights an important role of reactive oxygen species, mitochondrial adaptations and antioxidant responses in glucocorticoid induced programmed disease.

Stress and glucocorticoid receptor regulation of mitochondrial gene expression

Glucocorticoids have long been recognized for their role in regulating the availability of energetic resources, particularly during stress. Furthermore, bidirectional connections between glucocorticoids and the physiology and function of mitochondria have been discovered over the years. However, the precise mechanisms by which glucocorticoids act on mitochondria have only recently been explored. Glucocorticoids appear to regulate mitochondrial transcription via activation of glucocorticoid receptors (GRs) with elevated circulating glucocorticoid levels following stress. While several mechanistic questions remain, GR and other nuclear transcription factors appear to have the capacity to substantially alter mitochondrial transcript abundance. The regulation of mitochondrial transcripts by stress and glucocorticoids will likely prove functionally relevant in many stress-sensitive tissues including the brain.

A Mitochondrial Health Index Sensitive to Mood and Caregiving Stress

BACKGROUND

Chronic life stress, such as the stress of caregiving, can promote pathophysiology, but the underlying cellular mechanisms are not well understood. Chronic stress may induce recalibrations in mitochondria leading to changes either in mitochondrial content per cell, or in mitochondrial functional capacity (i.e., quality).

METHODS

Here we present a functional index of mitochondrial health (MHI) for human leukocytes that can distinguish between these two possibilities. The MHI integrates nuclear and mitochondrial DNA-encoded respiratory chain enzymatic activities and mitochondrial DNA copy number. We then use the MHI to test the hypothesis that daily emotional states and caregiving stress influence mitochondrial function by comparing healthy mothers of a child with an autism spectrum disorder (high-stress caregivers, n = 46) with mothers of a neurotypical child (control group, n = 45).

RESULTS

The MHI outperformed individual mitochondrial function measures. Elevated positive mood at night was associated with higher MHI, and nightly positive mood was also a mediator of the association between caregiving and MHI. Moreover, MHI was correlated to positive mood on the days preceding, but not following the blood draw, suggesting for the first time in humans that mitochondria may respond to proximate emotional states within days. Correspondingly, the caregiver group, which had higher perceived stress and lower positive and greater negative daily affect, exhibited lower MHI. This effect was not explained by a mismatch between nuclear and mitochondrial genomes.

CONCLUSIONS

Daily mood and chronic caregiving stress are associated with mitochondrial functional capacity. Mitochondrial health may represent a nexus between psychological stress and health.