1. |
- Blalock, Zachary N., et al.
(author)
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Circulating cell-free mitochondrial DNA levels and glucocorticoid sensitivity in a cohort of male veterans with and without combat-related PTSD
- 2024
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In: Translational Psychiatry. - 2158-3188. ; 14:1
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Journal article (peer-reviewed)abstract
- 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 η 2 = 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.
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2. |
- Dean, Kelsey R., et al.
(author)
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Multi-omic biomarker identification and validation for diagnosing warzone-related post-traumatic stress disorder
- 2020
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In: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 25:12, s. 3337-3349
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Journal article (peer-reviewed)abstract
- Post-traumatic stress disorder (PTSD) impacts many veterans and active duty soldiers, but diagnosis can be problematic due to biases in self-disclosure of symptoms, stigma within military populations, and limitations identifying those at risk. Prior studies suggest that PTSD may be a systemic illness, affecting not just the brain, but the entire body. Therefore, disease signals likely span multiple biological domains, including genes, proteins, cells, tissues, and organism-level physiological changes. Identification of these signals could aid in diagnostics, treatment decision-making, and risk evaluation. In the search for PTSD diagnostic biomarkers, we ascertained over one million molecular, cellular, physiological, and clinical features from three cohorts of male veterans. In a discovery cohort of 83 warzone-related PTSD cases and 82 warzone-exposed controls, we identified a set of 343 candidate biomarkers. These candidate biomarkers were selected from an integrated approach using (1) data-driven methods, including Support Vector Machine with Recursive Feature Elimination and other standard or published methodologies, and (2) hypothesis-driven approaches, using previous genetic studies for polygenic risk, or other PTSD-related literature. After reassessment of ~30% of these participants, we refined this set of markers from 343 to 28, based on their performance and ability to track changes in phenotype over time. The final diagnostic panel of 28 features was validated in an independent cohort (26 cases, 26 controls) with good performance (AUC = 0.80, 81% accuracy, 85% sensitivity, and 77% specificity). The identification and validation of this diverse diagnostic panel represents a powerful and novel approach to improve accuracy and reduce bias in diagnosing combat-related PTSD.
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3. |
- Bersani, Francesco S, et al.
(author)
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A population of atypical CD56(-)CD16(+) natural killer cells is expanded in PTSD and is associated with symptom severity
- 2016
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In: Brain Behavior and Immunity. - : Elsevier BV. - 1090-2139 .- 0889-1591. ; 56:August 2016, s. 264-270
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Post-traumatic stress disorder (PTSD) has been associated with immune disturbances, including a higher incidence of infections and autoimmune diseases as well as a net pro-inflammatory state. Natural killer (NK) cells, a key component of the innate immune system, have been less well-studied in PTSD despite their importance in immunity.METHODS: We studied two independent samples of combat-exposed male war veterans with or without PTSD, the first ("Discovery Sample") to generate hypotheses, and the second ("Validation Sample") to replicate the findings. The Discovery Sample was comprised of 42 PTSD subjects and 42 controls. The Validation Sample was comprised of 25 PTSD subjects and 30 controls. Participants had fasting, morning blood samples collected for examination of the frequency of NK cell subsets, determined by flow cytometry. The current and lifetime Clinician Administered PTSD Scale (CAPS) was used to assess symptom severity. Statistical analyses were adjusted for age and BMI.RESULTS: PTSD subjects compared to controls had (i) a significantly higher relative frequency of atypical CD56(-)CD16(+) NK cells in the Discovery Sample (p=0.027), which was replicated in the Validation Sample (p=0.004) and the combined sample (p<0.001), and (ii) a non-significantly lower relative frequency of CD56(bright)CD16(-) NK cells in the two samples (p=0.082; p=0.118), which became statistically significant in the combined sample (p=0.020). Further, within subjects with PTSD of both samples, the relative frequency of atypical CD56(-)CD16(+) NK cells was near significantly positively correlated with lifetime PTSD severity (p=0.074).DISCUSSION: This study is the first to characterize NK cell subsets in individuals with PTSD. The results suggest that combat-exposed men with PTSD exhibit an aberrant profile of NK cells with significantly higher frequencies of an atypical population of CD56(-)CD16(+) cells and possibly lower frequencies of the functional CD56(bright)CD16(-) NK cell subsets. Higher proportions of dysfunctional CD56(-)CD16(+) cells have been reported in certain chronic viral infections and in senescent individuals. It is possible that this could contribute to immune dysfunctions and prematurely senescent phenotypes seen in PTSD.
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4. |
- Bersani, F. Saverio, et al.
(author)
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Novel Pharmacological Targets for Combat PTSD-Metabolism, Inflammation, The Gut Microbiome, and Mitochondrial Dysfunction
- 2020
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In: Military medicine. - : Oxford University Press (OUP). - 1930-613X .- 0026-4075. ; 185:1, s. 311-318
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Journal article (peer-reviewed)abstract
- 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.
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5. |
- Blessing, Esther M., et al.
(author)
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Biological predictors of insulin resistance associated with posttraumatic stress disorder in young military veterans
- 2017
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In: Psychoneuroendocrinology. - : Elsevier BV. - 0306-4530. ; 82, s. 91-97
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Journal article (peer-reviewed)abstract
- Posttraumatic stress disorder (PTSD) is associated with increased risk for Type 2 diabetes and cardiovascular disease (cardiometabolic disease), warranting research into targeted prevention strategies. In the present case–control study of 160 young (mean age 32.7 years) male military veterans, we aimed to assess whether PTSD status predicted increased markers of cardiometabolic risk in otherwise healthy individuals, and further, to explore biological pathways between PTSD and these increased markers of cardiometabolic risk. Toward these aims, we compared measures of cardiometabolic risk, namely insulin resistance (IR) (HOMA-IR), metabolic syndrome (MetS) and prediabetes, between 80 PTSD cases and 80 controls without PTSD. We then determined whether PTSD-associated increases in HOMA-IR were correlated with select biological variables from pathways previously hypothesized to link PTSD with cardiometabolic risk, including systemic inflammation (increased C-reactive protein, interleukin-6, and tumor necrosis factor α), sympathetic over-activity (increased resting heart rate), and neuroendocrine dysregulation (increased plasma cortisol or serum brain-derived neurotrophic factor (BDNF)). We found PTSD diagnosis was associated with substantially higher HOMA-IR (cases 4.3 ± 4.3 vs controls 2.4 ± 2.0; p < 0.001), and a higher frequency of MetS (cases 21.3% vs controls 2.5%; p < 0.001), but not prediabetes (cases 20.0% vs controls 18.8%; p > 0.05). Cases also had increased pro-inflammatory cytokines (p < 0.01), heart rate (p < 0.001), and BDNF (p < 0.001), which together predicted increased HOMA-IR (adjusted R2 = 0.68, p < 0.001). Results show PTSD diagnosis in young male military veterans without cardiometabolic disease is associated with increased IR, predicted by biological alterations previously hypothesized to link PTSD to increased cardiometabolic risk. Findings support further research into early, targeted prevention of cardiometabolic disease in individuals with PTSD.
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6. |
- Bruno, Davide, et al.
(author)
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The recency ratio is associated with reduced CSF glutamate in late-life depression.
- 2017
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In: Neurobiology of learning and memory. - : Elsevier BV. - 1095-9564 .- 1074-7427. ; 141, s. 14-18
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Journal article (peer-reviewed)abstract
- Glutamate is the principal excitatory neurotransmitter in the central nervous system, and is thought to be involved in the process of memory encoding and storage. Glutamate disturbances have also been reported in psychiatric disorders, such as schizophrenia and major depressive disorder (MDD), and in Alzheimer's disease. In this paper, we set out to study the relationship between cerebrospinal fluid (CSF) glutamate levels and memory performance, which we believe has not been reported previously. In particular, we focused on recall performance broken down by serial position. Our prediction was that the recency ratio (Rr), a novel cognitive marker of intellectual impairment, would be linked with CSF glutamate levels. We studied data from a group of cognitively intact elderly individuals, 28 of whom had MDD, while 19 were controls. Study results indicated that Rr levels, but no other memory score, were inversely correlated with CSF glutamate levels, although this was found only in individuals with late-life MDD. For comparison, glutamine or GABA were not correlated with any memory performance measure.
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7. |
- Lindqvist, Daniel, et al.
(author)
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Increased circulating blood cell counts in combat-related PTSD : Associations with inflammation and PTSD severity
- 2017
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In: Psychiatry Research. - : Elsevier BV. - 0165-1781. ; 258, s. 330-336
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Journal article (peer-reviewed)abstract
- Inflammation is reported in post-traumatic stress disorder (PTSD). Few studies have investigated circulating blood cells that may contribute to inflammation. We assessed circulating platelets, white blood cells (WBC) and red blood cells (RBC) in PTSD and assessed their relationship to inflammation and symptom severity. One-hundred and sixty-three male combat-exposed veterans (82 PTSD, 81 non-PTSD) had blood assessed for platelets, WBC, and RBC. Data were correlated with symptom severity and inflammation. All cell counts were significantly elevated in PTSD. There were small mediation effects of BMI and smoking on these relationships. After adjusting for these, the differences in WBC and RBC remained significant, while platelet count was at trend level. In all subjects, all of the cell counts correlated significantly with inflammation. Platelet count correlated with inflammation only in the PTSD subjects. Platelet count, but none of the other cell counts, was directly correlated with PTSD severity ratings in the PTSD group. Combat PTSD is associated with elevations in RBC, WBC, and platelets. Dysregulation of all three major lineages of hematopoietic cells in PTSD, as well as their significant correlation with inflammation, suggest clinical significance of these changes.
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8. |
- Lindqvist, Daniel, et al.
(author)
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Increased pro-inflammatory milieu in combat related PTSD - A new cohort replication study
- 2017
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In: Brain Behavior and Immunity. - : Elsevier BV. - 1090-2139 .- 0889-1591. ; 59, s. 260-264
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Several lines of evidence indicate that increased inflammation is associated with Post-Traumatic Stress Disorder (PTSD). We have previously reported that peripheral inflammatory markers are significantly higher in combat-exposed veterans with than without PTSD. This study was designed to replicate these findings in a new study cohort using the same population and recruitment strategies.METHODS: Sixty-one male war veterans (31 PTSD and 30 control subjects) were included in this replication study. Levels of Interleukin-6, Tumor Necrosis Factor-alpha, Gamma interferon, and high-sensitivity C-reactive protein were quantified in blood samples. A standardized "total pro-inflammatory score" was calculated to limit the number of statistical comparisons. The Clinician Administered PTSD Scale (CAPS) rating scale was used to assess PTSD symptom severity.RESULTS: PTSD subjects had significantly higher total pro-inflammatory scores compared to non-PTSD subjects in unadjusted analysis (Cohen's d=0.75, p=0.005) as well as after adjusting for potentially confounding effects of age, BMI, smoking, and potentially interfering medications and somatic co-morbidities (p=0.023). There were no significant correlations between inflammatory markers and severity of symptoms within the PTSD group.CONCLUSIONS: We replicated, in a new sample, our previous finding of increased inflammatory markers in combat-exposed PTSD subjects compared to combat-exposed non-PTSD controls. These findings strongly add to the growing literature suggesting that immune activation may be an important aspect of PTSD pathophysiology, although not directly correlated with current PTSD symptom levels in the PTSD group.
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9. |
- Lindqvist, Daniel, et al.
(author)
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Proinflammatory milieu in combat-related PTSD is independent of depression and early life stress.
- 2014
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In: Brain Behavior and Immunity. - : Elsevier BV. - 1090-2139 .- 0889-1591. ; 42:Jun 12, s. 81-88
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Journal article (peer-reviewed)abstract
- Chronic inflammation may be involved in combat-related post-traumatic stress disorder (PTSD) and may help explain comorbid physical diseases. However, the extent to which combat exposure per se, depression, or early life trauma, all of which are associated with combat PTSD, may confound the relationship between PTSD and inflammation is unclear.
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10. |
- Pomara, Nunzio, et al.
(author)
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State-dependent alterations in cerebrospinal fluid Aβ42 levels in cognitively intact elderly with late-life major depression.
- 2016
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In: Neuroreport. - 1473-558X. ; 27:14, s. 1068-71
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Journal article (peer-reviewed)abstract
- Depression has been linked to Alzheimer's disease as either an increased risk factor for its development or as a prodromal symptom. The neurobiological basis for such an association, however, remains poorly understood. Numerous studies have examined whether changes in amyloid beta (Aβ) metabolism, which are implicated in the pathogenesis of Alzheimer's disease, are also found in depression. In this paper, we investigated the relationship between depressive symptoms and cerebrospinal fluid (CSF) Aβ indices in otherwise healthy, cognitively normal elderly with late-life major depression (LLMD) and controls using a longitudinal approach, which is a novel contribution toward the literature. Significantly lower levels of CSF Aβ42 were observed in the LLMD group at baseline and were associated with more severe depressive symptoms. During longitudinal follow-up, the depressed group remained cognitively unchanged, but was significantly less depressed than at baseline. A greater improvement in depressive symptoms was associated with increases in CSF Aβ42 levels in both groups. Increases in CSF Aβ42 and Aβ40 were also associated with increased CSF total-tau levels. Our results suggest that LLMD may be associated with state-dependent effects of CSF Aβ42 levels. Future studies should determine whether the association reflects state-dependent changes in neuronal activity and/or brain amyloid burden in depression.
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