| 1. |
- Björkstrand, Johannes, et al.
(author)
-
Decrease in amygdala activity during repeated exposure to spider images predicts avoidance behavior in spider fearful individuals.
- 2020
-
In: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 10:1
-
Journal article (peer-reviewed)abstract
- Spider phobia is characterized by exaggerated fear of situations where spiders could be present, resulting in avoidance of such situations and compromised quality of life. An important component in psychological treatment of spider phobia is exposure to phobic situations that reduces avoidance behaviors. At the neural level, amygdala responses to phobic material are elevated, but normalizes following exposure treatment. To what extent amygdala activity decreases during a session of repeated phobic stimulation, and whether activity decrease is related to subsequent avoidance is not well studied. We hypothesized reduced amygdala activity during the course of repeated exposure to spider pictures, and that the degree of reduction would predict subsequent avoidance of spider pictures. To test our hypothesis, functional magnetic resonance imaging was performed in 45 individuals with spider fear during repeated exposure to spider pictures. Results showed that repeated exposure to spider stimuli attenuated amygdala reactivity and individual differences in activity reductions predicted subsequent avoidance behavior to spider pictures in an incentive-conflict task, with larger attenuations predicting less avoidance. At 6-month follow up, initial reductions in amygdala activation still predicted avoidance. This result demonstrates that reduction in amygdala responses is related to clinically meaningful outcomes in human anxiety, and suggests that within-session reductions in amygdala responses could be an important mechanism explaining the clinical effects of exposure therapy.
|
|
| 2. |
- Blalock, Zachary N., et al.
(author)
-
Circulating cell-free mitochondrial DNA levels and glucocorticoid sensitivity in a cohort of male veterans with and without combat-related PTSD
- 2024
-
In: Translational Psychiatry. - 2158-3188. ; 14:1
-
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.
|
|
| 3. |
- Brundin, L., et al.
(author)
-
An enzyme in the kynurenine pathway that governs vulnerability to suicidal behavior by regulating excitotoxicity and neuroinflammation
- 2016
-
In: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 6
-
Journal article (peer-reviewed)abstract
- Emerging evidence suggests that inflammation has a key role in depression and suicidal behavior. The kynurenine pathway is involved in neuroinflammation and regulates glutamate neurotransmission. In the cerebrospinal fluid (CSF) of suicidal patients, levels of inflammatory cytokines and the kynurenine metabolite quinolinic acid (QUIN), an N-methyl-D-aspartate receptor agonist, are increased. The enzyme amino-beta-carboxymuconate-semialdehyde-decarboxylase (ACMSD) limits QUIN formation by competitive production of the neuroprotective metabolite picolinic acid (PIC). Therefore, decreased ACMSD activity can lead to excess QUIN. We tested the hypothesis that deficient ACMSD activity underlies suicidal behavior. We measured PIC and QUIN in CSF and plasma samples from 137 patients exhibiting suicidal behavior and 71 healthy controls. We used DSM-IV and the Montgomery-Asberg Depression Rating Scale and Suicide Assessment Scale to assess behavioral changes. Finally, we genotyped ACMSD tag single nucleotide polymorphisms (SNPs) in 77 of the patients and 150 population-based controls. Suicide attempters had reduced PIC and a decreased PIC/QUIN ratio in both CSF (P<0.001) and blood (P=0.001 and P<0.01, respectively). The reductions of PIC in CSF were sustained over 2 years after the suicide attempt based on repeated measures. The minor C allele of the ACMSD SNP rs2121337 was more prevalent in suicide attempters and associated with increased CSF QUIN. Taken together, our data suggest that increased QUIN levels may result from reduced activity of ACMSD in suicidal subjects. We conclude that measures of kynurenine metabolites can be explored as biomarkers of suicide risk, and that ACMSD is a potential therapeutic target in suicidal behavior.
|
|
| 4. |
- Elsworthy, R. J., et al.
(author)
-
The effect of citalopram treatment on amyloid-β precursor protein processing and oxidative stress in human hNSC-derived neurons
- 2022
-
In: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 12:1
-
Journal article (peer-reviewed)abstract
- Selective Serotonin Reuptake Inhibitors (SSRIs) may hold therapeutic benefits for people with Alzheimer’s disease (AD). SSRIs may perturb AD progression, or the conversion from MCI to AD, via increased neurogenesis, reduced oxidative stress and/or favourable Amyloid-β Precursor Protein (AβPP) processing. This study used iPSC derived cortical neuronal cells carrying 3 different PSEN1 mutations, to investigate the effect of treatment with the SSRI, Citalopram on AβPP processing and oxidative stress. Control and PSEN1 mutation (L286V, A246E, M146L) iPSC-derived neurons were treated with Citalopram for 45 days. ADAM10 activity, AβPP processing and Aβ generation was measured in addition to cellular redox status. Citalopram treatment reduced the Aβ1-42:40 ratio in control but not in fAD PSEN1 cells. ADAM10 activity was increased with Citalopram treatments in fAD PSEN1 cell lines, which was also seen for sAβPPα secretion. Lower superoxide generation in fAD PSEN1 cells following Citalopram treatment was identified, although there was no effect on end markers of oxidative stress. Treatment with Citalopram appears to have little effect on Aβ generation in fADPSEN1 cells, but our findings suggest that treatment can significantly increase non-amyloidogenic AβPP processing and reduce oxidative stress. These changes may explain why SSRIs appear most effective in the prodromal period of the disease progression, as opposed to reducing established AD pathology. Further investigation of specific pathways conferring the beneficial effects of SSRIs treatment are warranted.
|
|
| 5. |
- Fernström, Johan, et al.
(author)
-
Blood-based mitochondrial respiratory chain function in major depression
- 2021
-
In: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 11:1
-
Journal article (peer-reviewed)abstract
- Mitochondrial dysfunction has been implicated in major depressive disorder (MDD). A measure of mitochondrial respiratory chain (RC) enzymatic activity—the Mitochondrial Health Index (MHI)—has previously been found to correlate with stress and emotional states in caregivers. We here report mitochondrial RC activities, mitochondrial DNA copy number (mtDNAcn), and the composite MHI in unmedicated and somatically healthy subjects with MDD (n = 47) and healthy controls (HC) (n = 11). We also explore, in a subset of the MDD sample (n = 33), whether these markers are associated with response to 8 weeks of SSRI treatment. Mitochondrial RC complexes I, II, IV, citrate synthase (CS), mtDNAcn, and the MHI were assayed in peripheral blood mononuclear cells. Treatment response was defined as >50% decrease on the 25-item Hamilton Depression Rating Scale (HRDS-25). There were no significant differences in MHI or any of the mitochondrial markers between MDD subjects and HCs. Compared to SSRI nonresponders, SSRI responders had significantly higher baseline mitochondrial content markers CS (p = 0.02) and mtDNAcn (p = 0.02), and higher complex I activity (p = 0.01). Complex II activity increased significantly over treatment, irrespective of clinical response (p = 0.03). Complex I activity decreased in responders (n = 9), but increased in nonresponders (n = 18) (group x time interaction, p = 0.02). Absolute treatment-associated change in HDRS-25 scores correlated significantly with change in complex I activity between baseline and week 8 (r = 0.47, p = 0.01). Although mitochondrial markers did not distinguish MDD from controls, they did distinguish SSRI responders from nonresponders. If larger studies validate these mitochondrial differences, they may become useful biomarkers and identify new drug targets.
|
|
| 6. |
- Hjorth, Olof, et al.
(author)
-
Serotonin and dopamine transporter availability in social anxiety disorder after combined treatment with escitalopram and cognitive-behavioral therapy
- 2022
-
In: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 12:1
-
Journal article (peer-reviewed)abstract
- Selective serotonin reuptake inhibitors (SSRIs) and internet-based cognitive behavioral therapy (ICBT) are recommended treatments of social anxiety disorder (SAD), and often combined, but their effects on monoaminergic signaling are not well understood. In this multi-tracer positron emission tomography (PET) study, 24 patients with SAD were randomized to treatment with escitalopram+ICBT or placebo+ICBT under double-blind conditions. Before and after 9 weeks of treatment, patients were examined with positron emission tomography and the radioligands [11C]DASB and [11C]PE2I, probing the serotonin (SERT) and dopamine (DAT) transporter proteins respectively. Both treatment combinations resulted in significant improvement as measured by the Liebowitz Social Anxiety Scale (LSAS). At baseline, SERT-DAT co-expression was high and, in the putamen and thalamus, co-expression showed positive associations with symptom severity. SERT-DAT co-expression was also predictive of treatment success, but predictor-outcome associations differed in direction between the treatments. After treatment, average SERT occupancy in the SSRI + ICBT group was >80%, with positive associations between symptom improvement and occupancy in the nucleus accumbens, putamen and anterior cingulate cortex. Following placebo+ICBT, SERT binding increased in the raphe nuclei. DAT binding increased in both groups in limbic and striatal areas, but relations with symptom improvement differed, being negative for SSRI + ICBT and positive for placebo + ICBT. Thus, serotonin-dopamine transporter co-expression exerts influence on symptom severity and remission rate in the treatment of social anxiety disorder. However, the monoamine transporters are modulated in dissimilar ways when cognitive-behavioral treatment is given concomitantly with either SSRI-medication or pill placebo.
|
|
| 7. |
- Johansson, Maurits, et al.
(author)
-
Mild behavioral impairment and its relation to tau pathology in preclinical Alzheimer's disease
- 2021
-
In: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 11:1
-
Journal article (peer-reviewed)abstract
- Mild behavioral impairment (MBI) is suggested as risk marker for neurodegenerative diseases, such as Alzheimer's disease (AD). Recently, pathologic tau deposition in the brain has been shown closely related to clinical manifestations, such as cognitive deficits. Yet, associations between tau pathology and MBI have rarely been investigated. It is further debated if MBI precedes cognitive deficits in AD. Here, we explored potential mechanisms by which MBI is related to AD, this by studying associations between MBI and tau in preclinical AD. In all, 50 amyloid-beta -positive cognitively unimpaired subjects (part of the BioFINDER-2 study) underwent MBI-checklist (MBI-C) to assess MBI, and the Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog) delayed word recall (ADAS-DR) to assess episodic memory. Early tau pathology was determined using tau-PET ([F-18]RO948 retention in entorhinal cortex/hippocampus) and cerebrospinal fluid (CSF) P-tau(181). Regression models were used to test for associations. We found that higher tau-PET signal in the entorhinal cortex/hippocampus and CSF P-tau(181) levels were associated with higher MBI-C scores (beta =0.010, SE=0.003, p=0.003 and beta =1.263, SE=0.446, p=0.007, respectively). When MBI-C and ADAS-DR were entered together in the regression models, tau-PET (beta =0.009, p=0.009) and CSF P-tau(181) (beta =0.408, p=0.006) were predicted by MBI-C, but not ADAS-DR. We conclude that in preclinical AD, MBI is associated with tau independently from memory deficits. This denotes MBI as an important early clinical manifestation related to tau pathology in AD.
|
|
| 8. |
- Kendler, Kenneth S., et al.
(author)
-
The patterns of family genetic risk scores for eleven major psychiatric and substance use disorders in a Swedish national sample
- 2021
-
In: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 11:1
-
Journal article (peer-reviewed)abstract
- To clarify the structure of genetic risks for 11 major psychiatric disorders, we calculated, from morbidity risks for disorders in 1st–5th degree relatives controlling for cohabitation effects, in the Swedish population born between 1932 and 1995 (n = 5,830,014), the family genetic risk scores (FGRS) for major depression (MD), anxiety disorders (AD), obsessive-compulsive disorder (OCD), bipolar disorder (BD), schizophrenia (SZ), bulimia (BUL), anorexia nervosa (AN), alcohol use disorder (AUD), drug use disorder (DUD), ADHD, and autism-spectrum disorder (ASD). For all affected individuals, we calculated their mean standardized FGRS for each disorder. The patterns of FGRS were quite similar for MD and AD, and for AUD and DUD, but substantially less similar for BUL and AN, BD and SZ, and ADHD and ASD. While OCD had high levels of FGRS for MD and AD, the overall FGRS profile differed considerably from MD and AD. ADHD FGRS scores were substantially elevated in AUD and DUD. FGRS scores for BD, OCD, AN, ASD, ADHD, and especially SZ were relatively disorder-specific while genetic risk for MD and AD had more generalized effects. The levels of FGRS for BMI, coronary artery disease, and educational attainment across our disorders replicated prior associations found using molecular genetic methods. All diagnostic categories examined had elevated FGRS for many disorders producing, for each condition, an informative FGRS profile. Using a novel method which approximates, from pedigree data, aggregate genetic risk, we have replicated and extended prior insights into the structure of genetic risk factors for key psychiatric illnesses.
|
|
| 9. |
- Lindqvist, D., et al.
(author)
-
Increased plasma levels of circulating cell-free mitochondrial DNA in suicide attempters : associations with HPA-axis hyperactivity
- 2016
-
In: Translational Psychiatry. - : Nature Publishing Group. - 2158-3188. ; 6:12
-
Journal article (peer-reviewed)abstract
- Preclinical data suggest that chronic stress may cause cellular damage and mitochondrial dysfunction, potentially leading to the release of mitochondrial DNA (mtDNA) into the bloodstream. Major depressive disorder has been associated with an increased amount of mtDNA in leukocytes from saliva samples and blood; however, no previous studies have measured plasma levels of free-circulating mtDNA in a clinical psychiatric sample. In this study, free circulating mtDNA was quantified in plasma samples from 37 suicide attempters, who had undergone a dexamethasone suppression test (DST), and 37 healthy controls. We hypothesized that free circulating mtDNA would be elevated in the suicide attempters and would be associated with hypothalamic-pituitary-adrenal (HPA)-axis hyperactivity. Suicide attempters had significantly higher plasma levels of free-circulating mtDNA compared with healthy controls at different time points (pre- and post-DST; all P-values < 2.98E - 12, Cohen's d ranging from 2.55 to 4.01). Pre-DST plasma levels of mtDNA were positively correlated with post-DST cortisol levels (rho = 0.49, P < 0.003). Suicide attempters may have elevated plasma levels of free-circulating mtDNA, which are related to impaired HPA-axis negative feedback. This peripheral index is consistent with an increased cellular or mitochondrial damage. The specific cells and tissues contributing to plasma levels of free-circulating mtDNA are not known, as is the specificity of this finding for suicide attempters. Future studies are needed in order to better understand the relevance of increased free-circulating mtDNA in relation to the pathophysiology underlying suicidal behavior and depression.
|
|
| 10. |
- Momeni, Naghi, et al.
(author)
-
A novel blood-based biomarker for detection of autism spectrum disorders
- 2012
-
In: Translational Psychiatry. - : Nature Publishing Group. - 2158-3188. ; 2
-
Journal article (peer-reviewed)abstract
- Autism Spectrum Disorders (ASD) are classified as neurological developmental disorders. Several studies have been carried out to find a candidate biomarker linked to development of these disorders, but up to date no reliable biomarker is available. Mass spectrometry techniques have been used for protein profiling of blood plasma of children with such disorders in order to identify proteins/peptides which may be used as biomarkers for detection of the disorders. Three differentially expressed peptides with mass charged (m/z) values of 2,020 ± 1, 1,864 ± 1, and 1,978 ± 1 Da in heparin plasma of children with ASD which were significantly changed as compared to the peptide pattern of the non-ASD control group are reported here. This novel set of biomarkers allows for a reliable blood based diagnostic tool that may be used in diagnosis and potentially, in prognosis of ASD.
|
|
