Circulating biosignatures of late-life depression (LLD): Towards a comprehensive, data-driven approach to understanding LLD pathophysiology

An integration of neuroimaging and serum proteomics analysis suggests immune and inflammation are associated with white matter microstructure changes in cerebral small vessel disease with depressive symptoms

INTRODUCTION

Depressive symptoms are a common concomitant of cerebral small vessel disease (CSVD), of which pathogenesis requires more study. White matter microstructural abnormalities and proteomic alternation have been widely reported regarding depression in the elderly with CSVD. Exploring the relationship between cerebral white matter microstructural alterations and serum proteins may complete the explanation of molecular mechanisms for the findings from neuroimaging research of CSVD combined with depressive symptoms.

METHODS

An untargeted proteomics approach based on mass spectrometry was used to obtain serum proteomic profiles, which were clustered into co-expression protein modules. White matter microstructural integrity was measured using the FMRIB Software Library (FSL) and MATLAB to analyze diffusion tensor imaging (DTI) data and calculate the differences in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) for 50 regions of interest (ROI). Integrating the proteome with the DTI results, weighted gene co-expression analysis (WGCNA) was used to identify protein modules related to white matter microstructural alterations, and the proteins of the corresponding modules were analyzed for functional enrichment through bioinformatics techniques.

RESULTS

DTI measurements were analCerebral small vessel disease (CSVD); Depression; Diffusion tensor imaging (DTI); Proteomics; Inflammationyzed between individuals with CSVD and depressive symptoms (CSVD+D) (n = 24) and those without depressive symptoms (CSVD-D) (n = 35). Results showed an overall increase in MD, AD, and RD within the left hemisphere of the CSVD+D group, suggesting widespread loss of white matter integrity and axonal demyelination, including left superior longitudinal fasciculus (SLF), left posterior corona radiata (PCR) and right external capsule (EC). We identified two protein modules associated with DTI diffusivity, and functional enrichment analyses revealed that complement and coagulation cascades and immune responses participate in the alternation of white matter microstructure in the CSVD+D group.

CONCLUSION

The results suggested immune- and inflammation-related mechanism was associated with white matter microstructure changes in CSVD with depressive symptoms.

Elevated senescence-associated secretory phenotype index in late-life bipolar disorder

BACKGROUND

The senescence-associated secretory phenotype (SASP) is a biomarker index based on the profile of 22 blood proteins associated with cellular senescence. The SASP index has not been assessed in older patients with bipolar disorder (BD). We hypothesized that older adults with BD will have elevated cellular senescence burden as measured by the SASP index.

METHODS

We measured the 22 SASP proteins to calculate the SASP index in 38 older patients with BD and 34 non-psychiatric comparison individuals (HC).

RESULTS

The SASP index scores were significantly higher in BD than HC after controlling for age, sex, psychopathology, and physical health (F(1,8) = 5.37, p = 0.024, η2 = 0.08). SASP index scores were also associated with higher age, more severe depressive symptoms, and physical illness burden (p < 0.05) in the whole sample.

LIMITATION

Cross-sectional study and small sample size.

CONCLUSION

This is the first report of increased SASP index scores in older adults with BD. Our results suggest that dysregulation of age-related biological processes may contribute to more severe depressive symptoms and worse physical health in older adults with BD.

Unraveling the association between major depressive disorder and senescent biomarkers in immune cells of older adults: a single-cell phenotypic analysis

Background: Little is known about the prevalence of cellular senescence among immune cells (i.e., immune cells expressing senescence markers, iSCs) nor is there a gold-standard to efficiently measure iSCs. Major depressive disorder (MDD) in older adults has been associated with many hallmarks of senescence in whole blood, leukocytes, and plasma, supporting a strong connection between iSCs and MDD. Here, we investigated the prevalence and phenotype of iSCs in older adults with MDD. Using a single-cell phenotypic approach, circulating immune cells were examined for iSC biomarkers and their relationship to depression and inflammation. Results: PBMCs from older adults with MDD (aged 69.75 ± 5.23 years) and healthy controls (aged 71.25 ± 8.8 years) were examined for immune subset distribution and senescence biomarkers (i.e., lack of proliferation, senescence-associated heterochromatin foci (SAHF), and DNA damage). Dual-expression of SAHF and DNA damage was categorized by low, intermediate, and high expression. A significant increase in the number of high expressing total PBMCs (p = 0.01), monocytes (p = 0.008), a trending increase in the number of high expressing CD4 T cells (p = 0.06) was observed overall in those with MDD. There was also a significantly lower proportion of intermediate expressing cells in monocytes and CD4 T cells in MDD (p = 0.01 and p = 0.05, respectively). Correlation analysis revealed associations between iSCs and mRNA expression of factors related to SASP and immune cell function. Conclusion: MDD is associated with increased senescent cell biomarkers in immune cell populations delineated by distinct levels of SAHF and DNA damage. Inflammatory markers might serve as potent indicators of iSC burden in MDD.

Sex differences in plasma proteomic markers in late-life depression

Previous studies have shown significant sex-specific differences in major depressive disorder (MDD) in multiple biological parameters. Most studies focused on young and middle-aged adults, and there is a paucity of information about sex-specific biological differences in older adults with depression (aka, late-life depression (LLD)). To address this gap, this study aimed to evaluate sex-specific biological abnormalities in a large group of individuals with LLD using an untargeted proteomic analysis. We quantified 344 plasma proteins using a multiplex assay in 430 individuals with LLD and 140 healthy comparisons (HC) (age range between 60 and 85 years old for both groups). Sixty-six signaling proteins were differentially expressed in LLD (both sexes). Thirty-three proteins were uniquely associated with LLD in females, while six proteins were uniquely associated with LLD in males. The main biological processes affected by these proteins in females were related to immunoinflammatory control. In contrast, despite the smaller number of associated proteins, males showed dysregulations in a broader range of biological pathways, including immune regulation pathways, cell cycle control, and metabolic control. Sex has a significant impact on biomarker changes in LLD. Despite some overlap in differentially expressed biomarkers, males and females show different patterns of biomarkers changes, and males with LLD exhibit abnormalities in a larger set of biological processes compared to females. Our findings can provide novel targets for sex-specific interventions in LLD.

Serum proteomic biomarker investigation of vascular depression using data-independent acquisition: a pilot study

Background

Vascular depression (VaD) is a depressive disorder closely associated with cerebrovascular disease and vascular risk factors. It remains underestimated owing to challenging diagnostics and limited information regarding the pathophysiological mechanisms of VaD. The purpose of this study was to analyze the proteomic signatures and identify the potential biomarkers with diagnostic significance in VaD.

Methods

Deep profiling of the serum proteome of 35 patients with VaD and 36 controls was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Functional enrichment analysis of the quantified proteins was based on Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and Reactome databases. Machine learning algorithms were used to screen candidate proteins and develop a protein-based model to effectively distinguish patients with VaD.

Results

There were 29 up-regulated and 31 down-regulated proteins in the VaD group compared to the controls (|log2FC| ≥ 0.26, p ≤ 0.05). Enrichment pathways analyses showed that neurobiological processes related to synaptic vesicle cycle and axon guidance may be dysregulated in VaD. Extrinsic component of synaptic vesicle membrane was the most enriched term in the cellular components (CC) terms. 19 candidate proteins were filtered for further modeling. A nomogram was developed with the combination of HECT domain E3 ubiquitin protein ligase 3 (HECTD3), Nidogen-2 (NID2), FTO alpha-ketoglutarate-dependent dioxygenase (FTO), Golgi membrane protein 1 (GOLM1), and N-acetylneuraminate lyase (NPL), which could be used to predict VaD risk with favorable efficacy.

Conclusion

This study offers a comprehensive and integrated view of serum proteomics and contributes to a valuable proteomics-based diagnostic model for VaD.

Challenges in Identifying Individualized Brain Biomarkers of Late Life Depression

Research into neuroimaging biomarkers for Late Life Depression (LLD) has identified neural correlates of LLD including increased white matter hyperintensities and reduced hippocampal volume. However, studies into neuroimaging biomarkers for LLD largely fail to converge. This lack of replicability is potentially due to challenges linked to construct variability, etiological heterogeneity, and experimental rigor. We discuss suggestions to help address these challenges, including improved construct standardization, increased sample sizes, multimodal approaches to parse heterogeneity, and the use of individualized analytical models.

Major depression and the biological hallmarks of aging

Major depressive disorder (MDD) is characterized by psychological and physiological manifestations contributing to the disease severity and outcome. In recent years, several lines of evidence have suggested that individuals with MDD have an elevated risk of age-related adverse outcomes across the lifespan. This review provided evidence of a significant overlap between the biological abnormalities in MDD and biological changes commonly observed during the aging process (i.e., hallmarks of biological aging). Based on such evidence, we formulate a mechanistic model showing how abnormalities in the hallmarks of biological aging can be a common denominator and mediate the elevated risk of age-related health outcomes commonly observed in MDD. Finally, we proposed a roadmap for novel studies to investigate the intersection between the biology of aging and MDD, including the use of geroscience-guided interventions, such as senolytics, to delay or improve major depression by targeting biological aging.

Plasma proteomic signature of major depressive episode in the elderly

Depression is a complex and multifactorial disease, affecting about 6.5% of the elderly population in what is referred to as late-life depression (LLD). Despite its public health relevance, there is still limited information about the molecular mechanisms of LLD. We analyzed the blood plasma of 50 older adults, 19 with LLD and 31 controls, through untargeted mass spectrometry, and used systems biology tools to identify biochemical pathways and biological processes dysregulated in the disease. We found 96 differentially expressed proteins between LLD patients and control individuals. Using elastic-net regression, we generated a panel of 75 proteins that comprises a potential model for determining the molecular signature of LLD. We also showed that biological pathways related to vesicle-mediated transport and voltage-dependent calcium channels may be dysregulated in LLD. These data can help to build an understanding of the molecular basis of LLD, offering an integrated view of the biomolecular alterations that occur in this disorder. SIGNIFICANCE: Major depressive disorder in the elderly, called late-life depression (LLD), is a common and disabling disorder, with recent prevalence estimates of 6.5% in the general population. Despite the public health relevance, there is still limited information about the molecular mechanisms of LLD. The findings in this paper shed light on LLD heterogeneous biological mechanisms. We uncovered a potential novel biomolecular signature for LLD and biological pathways related to this condition which can be targets for the development of novel interventions for prevention, early diagnosis, and treatment of LLD.

Association of Molecular Senescence Markers in Late-Life Depression With Clinical Characteristics and Treatment Outcome

IMPORTANCE

Many older adults with depression do not experience remission with antidepressant treatment, and markers of cellular senescence in late-life depression (LLD) are associated with greater severity of depression, greater executive dysfunction, and higher medical illness burden. Since these clinical characteristics are associated with remission in LLD, molecular and cellular senescence abnormalities could be a possible biological mechanism underlying poor treatment response in this population.

OBJECTIVE

To examine whether the senescence-associated secretory phenotype (SASP) index was associated with the likelihood of remission from a depressive episode in older adults.

DESIGN, SETTING, AND PARTICIPANTS

A nonrandomized, open-label clinical trial was conducted between August 2009 and August 2014 in Pittsburgh, Pennsylvania; St Louis, Missouri; and Toronto, Ontario, Canada, with older adults in a current major depressive episode according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) diagnostic criteria. Data from biomarker analyses were reported according to the clinical trial archived plasma samples run in March 2021. Data were analyzed from June to November 2021.

EXPOSURE

Venlafaxine extended release (dose ranging from 37.5 mg to 300 mg daily) for up to 12 weeks.

MAIN OUTCOMES AND MEASURES

The association between a composite biomarker-based index (SASP index) and treatment remission in older adults with major depression was measured using clinical data and blood samples.

RESULTS

There were 416 participants with a mean (SD) age of 60.02 (7.13) years; 64% (265 participants) were self-reported female, and the mean (SD) Montgomery-Asberg Depression Rating Scale score was 26.6 (5.7). Higher SASP index scores were independently associated with higher rates of nonremission, with an increase of 1 unit in the SASP index score increasing the odds of nonremission by 19% (adjusted odds ratio, 1.19; 95% CI, 1.05-1.35; P = .006). In contrast, no individual SASP factors were associated with remission in LLD.

CONCLUSIONS AND RELEVANCE

Using clinical data and blood samples from a nonrandomized clinical trial, the results of this study suggest that molecular and cellular senescence, as measured with the SASP index, is associated with worse treatment outcomes in LLD. Combining this index score reflecting interrelated biological processes with other molecular, clinical, and neuroimaging markers may be useful in evaluating antidepressant treatment outcomes. These findings inform a path forward for geroscience-guided interventions targeting senescence to improve remission rates in LLD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00892047.

Increased Levels of Circulating Cell-Free mtDNA in the Plasma of Subjects With Late-Life Depression and Frailty: A Preliminary Study

OBJECTIVE

To evaluate the circulating cell-free mitochondrial DNA (ccf-mtDNA) levels, a marker of cellular stress and damage, in older adults with late-life depression (LLD) and frailty. We hypothesize that individuals with both frailty and LLD will have higher ccf-mtDNA levels than individuals with either condition in isolation.

METHODS

Fifty-three older adults (Never Depressed+Robust (reference group, n = 16), LLD+Robust (n = 9), Never Depressed+Prefrail/Frail (n = 5), and LLD+Prefrail/Frail (n = 23)) were included in the study. DNA was extracted from EDTA plasma samples, and ccf-mtDNA was quantified by RT-PCR.

RESULTS

We found a statistically significant difference in the levels of ccf-mtDNA across groups (F_(3,49) = 3.07, p = 0.036), with individuals in the LLD+Prefrail/Frail group showing the highest levels of ccf-mtDNA.

CONCLUSION

The coexistence of LLD and frailty is associated with increased markers of cellular damage and stress (i.e., ccf-mtDNA). Our results suggest that these conditions may share cellular stress and mitochondrial dysfunction phenomena as a common biological mechanism, offering potential future opportunities for geroscience-guided interventions for these conditions.

Depressive symptom profiles predict dementia onset and brain pathology in older persons. The AGES-Reykjavik study

Late-life depression (LLD) increases risk for dementia and brain pathology, but possibly this is only true for one or more symptom profiles of LLD. In 4354 participants (76 ± 5 years; 58% female) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study, we identified five LLD symptom profiles, based on the Geriatric Depression Scale-15 (no LLD (57%); apathy (31%); apathy with emptiness (2%), mild LLD (8%) and severe LLD (2%)). Cox regression analyses showed that severe LLD, mild LLD and apathy increased risk of dementia up to 12 years, compared to no LLD. Additionally, hippocampal volume loss and white matter lesion increase, were assessed on 1.5 T MR images, at baseline and after 5 years follow-up. Only severe LLD showed increased WML volume over time, but not on hippocampal volume loss. WML increase over time mediated partially the relation between mild LLD and dementia but not for the other symptom profiles. It appears that hippocampal atrophy and LLD are independent predictors for dementia incidence, whereas for mild LLD the risk for dementia is partially mediated by WML changes.

Increased levels of circulating cell-free mtDNA in plasma of late life depression subjects

BACKGROUND

Oxidative stress (OS) has been implicated in the pathophysiology of late-life depression (LLD). Mitochondria are the primary source of oxidative stress and can be significantly damaged with increased OS. Circulating cell-free mtDNA (ccf-mtDNA) is a marker of cellular stress and mitochondria damage triggered by oxidative stress.

METHODS

We evaluated the plasma levels of ccf-mtDNA in between 32 LLD and 21 never-depressed participants. We also investigated the association between ccf-mtDNA and the severity of depressive episodes and cognition performance.

RESULTS

We found a higher ccf-mtDNA level in LLD cases compared with controls (t = -2.91, p = 0.005). Also, ccf-mtDNA was significantly correlated with the severity of depression (r = 0.42, p = 0.001). There was no significant correlation between ccf-mtDNA and measures of cognitive decline.

LIMITATIONS

The small sample size and cross-sectional design were the main limitations of this study.

CONCLUSION

Our results suggest that LLD is associated with elevated mitochondrial damage and cellular stress. If validated, the measurement of ccf-mtDNA in LLD can guide the development of novel treatments focused on cytoprotection and reduction of mitochondrial dysfunction for this condition.

Mild cognitive impairment and major depressive disorder are associated with molecular senescence abnormalities in older adults

INTRODUCTION

The biological mechanisms linking mild cognitive impairment (MCI) and major depressive disorder are not well understood. We investigated whether molecular senescence changes in older adults are associated with a history of major depressive disorder (MDD) or MCI.

METHODS

We included 371 participants: 167 with MCI; 62 cognitively normal with a history of MDD; 97 with MDD+MCI; and 45 cognitively unimpaired (CU) without a history of MDD. The candidate Senescence-Associated Secretory Phenotype (SASP) biomarkers were measured in the plasma using a customized LUMINEX assay.

RESULTS

The MDD+MCI group had a higher SASP index than the other groups (P < .001). A higher SASP index was significantly associated with worse global cognitive performance, executive dysfunction, slower processing speed, and episodic memory deficits.

DISCUSSION

Our study suggests that increased molecular changes are associated with cognitive impairment in older adults with MDD and indicate that accelerated biological aging is an underlying feature of MDD.

Depression Augments Plasma APOA4 without Changes of Plasma Lipids and Glucose in Female Adolescents Carrying G Allele of APOA4 rs5104

The association of apolipoprotein AIV (APOA4) with depression or plasma levels of lipids and glucose has been inconsistently reported. However, interplays between APOA4 and depression on the levels have not been explored yet. The present study aimed to investigate plasma levels of APOA4, lipids, and glucose in adolescents with different genotypes of APOA4 rs5104 and with or without depression. Depressive symptoms were assessed in 631 adolescents by Beck Depression Inventory (BDI). A total score of 14 was defined as the cutoff point for depression. Plasma levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glucose, and insulin were measured by routine methods, and APOA4 by enzyme-linked immunosorbent assays. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism analyses and verified by DNA sequencing. Female adolescents had higher prevalence of depression than male subjects only in G allele carriers (p = 0.015), but not in AA homozygotes. Risk factors of depression and predictors of depression severity were different between G allele carriers and AA homozygotes. Lower levels of glucose (p = 0.003) were observed in male G allele carriers than those in male AA homozygotes and increased TG levels (p = 0.008) in female G allele carriers when compared with those in female AA homozygotes. When both APOA4 rs5104 and depression were taken into account, subjects with depression had higher levels of plasma APOA4 than adolescents without depression only in female G allele carriers (p = 0.043), but no significant changes of plasma lipids and glucose. Depression augments plasma APOA4 levels without changes of plasma lipids and glucose in female adolescents carrying G allele of APOA4 rs5104. These results may provide a novel explanation for the inconsistent relationship between depression, APOA4, and plasma levels of lipids and glucose in the literature.

Influence of genetic polymorphisms in homocysteine and lipid metabolism systems on antidepressant drug response

BACKGROUND

Variation in genes implicated in homocysteine and lipid metabolism systems may influence antidepressant response for patients with major depressive disorder (MDD). This study aimed to investigate whether association of polymorphisms on the MTHFR, ApoE and ApoA4 genes with the treatment response in MDD subjects.

METHODS

A total of 281 Han Chinese MDD patients received a single antidepressant drug (SSRI or SNRI) for at least 6 weeks, among whom 275 were followed up for 8 weeks. Their response to 6 weeks' treatment and remission to 8 weeks' treatment with antidepressant drugs was determined by changes in the 17-item Hamilton Depression Rating Scale (HARS-17) score. Single SNP and haplotype associations with treatment response were analyzed by UNPHASED 3.0.13. Logistic regression analysis was used to explore the interactions between genotypes and gender or drug type on treatment outcome, only those SNPs that had interactional association with gender or drug type were subjected to further stratified analysis.

RESULTS

In total group, the haplotype (C-A) in MTHFR (rsl801133 and rs1801131) and the ApoE rs405509 AA genotype were significantly associated with better efficacy of antidepressants; In gender subgroups, only haplotype (C-A) in MTHFR (rsl801133 and rs1801131) was significantly associated with better efficacy of antidepressants in male subgroup; In drug type subgroup, the haplotype (C-A) in MTHFR (rsl801133 and rs1801131) and haplotype (G-C) in ApoE (rs7412 and rs405509) were associated with better efficacy of antidepressants in SNRI treated subgroup; The ApoA4 rs5092 G allele and GG genotype were associated with worse efficacy of antidepressants in SNRI treated subgroup.

CONCLUSIONS

Genetic polymorphisms in homocysteine and lipid metabolism systems are associated with antidepressant response, particularly for the interactions of the certain genetic with gender or drug type.

Depression in the Elderly. Consensus Statement of the Spanish Psychogeriatric Association

INTRODUCTION

Present knowledge about depression in the elderly is still scarce and often controversial, despite its high frequency and impact. This article reports the results and most relevant conclusions of a Delphi-based consensus on geriatric depression promoted by the Spanish Psychogeriatric Association.

METHODS

A 78-item questionnaire was developed by 7 highly specialized geriatric psychiatrists and was evaluated using the Modified Delphi technique in two rounds answered by 35 psychiatrists with an extensive expertise in geriatric depression. The topics and number of questions (in brackets) covered were: concepts, clinical aspects, and risk factors (12); screening and diagnosis (7); psychotic depression (17); depression and dementia (5); antidepressant drug treatment (18); non-pharmacological biological treatments (5); psychotherapeutic treatments (4); comorbidity and preventive aspects (6); professional training needed (4). In addition, the expert panel's opinion on the antidepressants of choice in 21 common comorbid conditions and on different strategies to approach treatment-resistant cases in terms of both efficacy and safety was assessed.

RESULTS

After the two rounds of the Delphi process, consensus was reached for 59 (75.6%) of the 78 items. Detailed recommendations are included in the text. Considering pharmacological treatments, agomelatine was the most widely mentioned drug to be recommended in terms of safety in comorbid conditions. Desvenlafaxine, sertraline, and vortioxetine, were the most frequently recommended antidepressants in comorbid conditions in general. Combining parameters of efficacy and safety, experts recommended the following steps to address cases of treatment resistance: 1. Escalation to the maximum tolerated dose; 2. Change of antidepressant; 3. Combination with another antidepressant; 4. Potentiation with an antipsychotic or with lamotrigine; 5. Potentiation with lithium; 6. Potentiation with dopamine agonists or methylphenidate.

DISCUSSION AND CONCLUSIONS

Consensus was reached for a high number of items as well as for the management of depression in the context of comorbid conditions and in resistant cases. In the current absence of sufficient evidence-based information, our results can be used to inform medical doctors about clinical recommendations that might reduce uncertainty in the diagnosis and treatment of elderly patients with depressive disorders.

Evidence for Structural and Functional Alterations of Frontal-Executive and Corticolimbic Circuits in Late-Life Depression and Relationship to Mild Cognitive Impairment and Dementia: A Systematic Review

Depression is a risk factor for developing Alzheimer's disease and Related Dementia (ADRD). We conducted a systematic review between 2008 and October 2018, to evaluate the evidence for a conceptual mechanistic model linking depression and ADRD, focusing on frontal-executive and corticolimbic circuits. We focused on two neuroimaging modalities: diffusion-weighted imaging measuring white matter tract disruptions and resting-state functional MRI measuring alterations in network dynamics in late-life depression (LLD), mild cognitive impairment (MCI), and LLD+MCI vs. healthy control (HC) individuals. Our data synthesis revealed that in some but not all studies, impairment of both frontal-executive and corticolimbic circuits, as well as impairment of global brain topology was present in LLD, MCI, and LLD+MCI vs. HC groups. Further, posterior midline regions (posterior cingulate cortex and precuneus) appeared to have the most structural and functional alterations in all patient groups. Future cohort and longitudinal studies are required to address the heterogeneity of findings, and to clarify which subgroups of people with LLD are at highest risk for developing MCI and ADRD.

Internet-Based Management for Depressive Disorder

The advances in the Internet and related technologies may lead to changes in professional roles of psychiatrists and psychotherapists. The application of artificial intelligence (AI) and electronic measurement-based care (eMBC) in the treatment of depressive disorder has addressed more interest. AI could play a role in population health management and patient administration as well as assist physicians to make a decision in the real-world clinical practice. The eMBC strengthens MBC through web/mobile devices and telephone consulting services, to monitor disease progression, and customizes the MBC interface in electronic medical record systems (EMRs).

Molecular Senescence Is Associated With White Matter Microstructural Damage in Late-Life Depression

OBJECTIVES

The authors aim to investigate the association between white matter integrity and accelerated brain aging in late-life depression.

METHODS

The authors measured senescence-associated secretory phenotype (SASP) index proteins, cognitive performance, and MRI diffusion tensor imaging (DTI) measures of fractional anisotropy and mean diffusivity-based indices of white matter microstructure measures in 56 older adults with remitted late-life depression.

RESULTS

Higher SASP index was significantly correlated with older age (r = 0.42, p = 0.001) and worse executive function performance (r = -0.27, p = 0.04). After controlling for the effect of age, overall cognitive performance, and white matter hyperintensities, the association between SASP and left and right cingulate bundle mean diffusivity remained statistically significant.

CONCLUSIONS

Our data suggest that, in the context of late-life depression, SASP proteins are associated with microstructural abnormalities in white matter tracts in brain and worse executive function performance.

Major depression and enhanced molecular senescence abnormalities in young and middle-aged adults

Recent evidence suggests a significant overlap in biological changes between major depression and aging across the lifespan. We aim to evaluate the impact of a major depressive episode on the Senescence-Associated Secretory Phenotype (SASP) index, a dynamic secretory molecular pattern indicative of cellular senescence. We also tested the potential moderators of the association between major depression and the SASP index. We included 1165 young and middle-aged adults (527 with a current major depressive episode (cMDE) and 638 with no lifetime history of depression) from a community-based cohort from the Netherlands. We calculated the SASP index based on a previously developed composite index involving 19 biomarkers. cMDE had higher SASP index values (t₍₁₁₆₃₎ = 2.93, p = 0.003) compared to controls in the univariate analysis. After controlling for sociodemographic and somatic health covariates, there was no significant association between cMDE and SASP index (F_(1,1158) = 1.09, p = 0.29). Those with the most severe depressive episodes had significantly higher SASP indices compared to those with mild-to-moderate cMDE and controls (F_(2,1162) = 6.73, p = 0.001). We found a significant interaction between cMDE and overweight (F_(1,1164) = 5.1, p = 0.028): those with comorbid cMDE and overweight had the highest SASP index. Our study demonstrated a complex interaction between cMDE and medical morbidity, especially overweight, on the SASP index, suggesting that their coexistence aggravate age-related biological processes. Moreover, higher SASP index can be a biomarker for more severe depressive episodes.

Longitudinal Association of Depression Symptoms With Cognition and Cortical Amyloid Among Community-Dwelling Older Adults

IMPORTANCE

Depressive symptoms are prevalent among older adults and may be early manifestations of Alzheimer disease (AD) before onset of mild cognitive impairment. However, it remains unclear whether worsening depressive symptoms in the presence of AD pathology are associated with cognitive decline in older adults.

OBJECTIVE

To determine the longitudinal association between depressive symptoms, cognition, and cortical amyloid in community-dwelling older adults.

DESIGN, SETTING, AND PARTICIPANTS

Participants from the Harvard Aging Brain Study, a cohort study, underwent annual assessments of depression and cognition and baseline cortical amyloid measurement (mean, 4.42 years; range, 2-7 years). Data collection was from September 2010 to August 2017 in a convenience sample of community-dwelling adults (276 participants, all cognitively unimpaired) with at most mild depression at entry.

MAIN OUTCOMES AND MEASURES

Depression (Geriatric Depression Scale [GDS]), cognition (Preclinical Alzheimer Cognitive Composite [PACC]), and a continuous measure of cortical amyloid (Pittsburgh Compound-B positron emission tomography imaging). Change in GDS and baseline amyloid were examined as interactive predictors of PACC decline in a linear mixed model with backward elimination, adjusting for age, sex, and education.

RESULTS

Participants were 164 women and 112 men (mean [SD] age, 73.5 [6.0] years). At baseline, the mean (SD) GDS score was 3.0 (2.8) (range, 0-12), the mean (SD) PACC score was -0.004 (0.67) (range, -2.32 to 1.88), and the mean (SD) amyloid positron emission tomography distribution volume ratio was 1.16 (0.20) (range, 0.92-1.94). At last follow-up, the mean (SD) GDS score was 3.9 (2.9) (range, 0-12), and the mean (SD) PACC score was -0.09 (1.27) (range, -5.66 to 1.67). The interaction between cortical amyloid and increasing GDS was associated with declining cognition (β = -0.19; 95% CI, -0.27 to -0.12; P < .001).

CONCLUSIONS AND RELEVANCE

In this study, cortical amyloid moderated the association between worsening depressive symptoms and declining cognition in older adults. While future work is needed to better understand causal associations, these findings may enhance early detection and prevention of AD clinical symptoms.

Machine learning in mental health: a scoping review of methods and applications

BACKGROUND

This paper aims to synthesise the literature on machine learning (ML) and big data applications for mental health, highlighting current research and applications in practice.

METHODS

We employed a scoping review methodology to rapidly map the field of ML in mental health. Eight health and information technology research databases were searched for papers covering this domain. Articles were assessed by two reviewers, and data were extracted on the article's mental health application, ML technique, data type, and study results. Articles were then synthesised via narrative review.

RESULTS

Three hundred papers focusing on the application of ML to mental health were identified. Four main application domains emerged in the literature, including: (i) detection and diagnosis; (ii) prognosis, treatment and support; (iii) public health, and; (iv) research and clinical administration. The most common mental health conditions addressed included depression, schizophrenia, and Alzheimer's disease. ML techniques used included support vector machines, decision trees, neural networks, latent Dirichlet allocation, and clustering.

CONCLUSIONS

Overall, the application of ML to mental health has demonstrated a range of benefits across the areas of diagnosis, treatment and support, research, and clinical administration. With the majority of studies identified focusing on the detection and diagnosis of mental health conditions, it is evident that there is significant room for the application of ML to other areas of psychology and mental health. The challenges of using ML techniques are discussed, as well as opportunities to improve and advance the field.

Fatigue in primary Sjögren's syndrome: A proteomic pilot study of cerebrospinal fluid

Objectives:

Fatigue is a frequent and often disabling phenomenon that occurs in patients with chronic inflammatory and immunological diseases, and the underlying biological mechanisms are largely unknown. Because fatigue is generated in the brain, we aimed to investigate cerebrospinal fluid and search for molecules that participate in the pathophysiology of fatigue processes.

Methods:

A label-free shotgun proteomics approach was applied to analyze the cerebrospinal fluid proteome of 20 patients with primary Sjögren’s syndrome. Fatigue was measured with the fatigue visual analog scale.

Results:

A total of 828 proteins were identified and the 15 top discriminatory proteins between patients with high and low fatigue were selected. Among these were apolipoprotein A4, hemopexin, pigment epithelium-derived factor, secretogranin-1, secretogranin-3, selenium-binding protein 1, and complement factor B.

Conclusion:

Most of the discriminatory proteins have important roles in regulation of innate immunity, cellular stress defense, and/or functions in the central nervous system. These proteins and their interacting protein networks may therefore have central roles in the generation and regulation of fatigue, and the findings contribute with evidence to the concept of fatigue as a biological phenomenon signaled through specific molecular pathways.

Brain IGFBP-5 modifies the relation of depressive symptoms to decline in cognition in older persons

BACKGROUND

Brain proteins, including Insulin-like Growth Factor Binding Protein 5 (IGFBP-5), have been associated with cognitive dysfunction in aging. Mechanisms linking depression with cognition are poorly understood. We hypothesize that the association of depressive symptoms with cognition is mediated or modified by brain proteins.

METHODS

IGFBP-5, HSPB2, AK4, ITPK1 and PLXNB1 were measured in dorsolateral prefrontal cortex in 1057 deceased participants, who underwent annual assessments of depressive symptoms and cognition for a mean of 8.9 years. The average number of depressive symptoms per year before a dementia diagnosis was calculated for each person.

RESULTS

A one standard deviation above the mean IGFBP-5 was associated with a 14% higher odds of having more depressive symptoms (p < 0.031). Higher IGFBP-5 was associated with faster decline in global cognition (p < 0.001) and five cognitive domains (p < 0.008), controlling for depressive symptoms. IGFBP-5 moderated the association of depressive symptoms with decline in global cognition (p = 0.045). IGFBP-5 mediated ten percent or less of the total effect of depressive symptoms on decline in global cognition and the cognitive domains (p > 0.070).

LIMITATIONS

Participants were volunteers and self-selection bias limits the generalizability of our findings. In addition, we used self-reported data on depressive symptoms. However, we also used data on depression medications as sensitivity analyses to confirm findings.

CONCLUSIONS

In old age, brain IGFBP-5 is associated with depressive symptoms and cognition. The association of depressive symptoms with cognitive decline is conditional on IGFBP-5.

Brain-enriched MicroRNA-184 is downregulated in older adults with major depressive disorder: A translational study

Changes in microRNAs (miRNAs) expression have been described in major depressive disorder in young and middle-aged adults. However, no study has evaluated miRNA expression in older adults with major depression (or late-life depression [LLD]). Our primary aim was to evaluate the expression of miRNAs in subjects with LLD. We first evaluated the miRNA expression using next-generation sequencing (NGS) and then we validated the miRNAs found in NGS in an independent sample of LLD patients, using RT-qPCR. Drosophila melanogaster model was used to evaluate the impact of changes in miRNA expression on behavior. NGS analysis showed that hsa-miR-184 (log₂foldchange = -4.21, p = 1.2 × 10^-03) and hsa-miR-1-3p (log₂foldchange = -3.45, p = 1.3 × 10^-02) were significantly downregulated in LLD compared to the control group. RT-qPCR validated the downregulation of hsa-miR-184 (p < 0.001), but not for the hsa-miR-1-3p. The knockout flies of the ortholog of hsa-miR-184 showed significantly reduced locomotor activity at 21-24 d.p.e (p = 0.04) and worse memory retention at 21-24 d.p.e (24h post-stimulus, p = 0.02) compared to control flies. Our results demonstrated that subjects with LLD have significant downregulation of hsa-miR-184. Moreover, the knockout of hsa-miR-184 in flies lead to depressive-like behaviors, being more pronounce in older flies.

Epidermal growth factor and fibroblast growth factor-2 circulating levels in elderly with major depressive disorder

Epidermal growth factor (EGF) and Fibroblast Growth Factor-2 (FGF-2) are growth factors involved neuronal growth and synaptic plasticity. These markers have been implicated in neuropsychiatric disorders, including major depression. However, no particular studies of EGF and FGF-2 have been conducted in older adults with major depressive disorder (MDD). In this study, we aim to investigate the plasma levels of EGF and FGF-2 in elderly with MDD. We included 89 older adults with MDD and 51 older (healthy control, HC) adults. The cognitive performance was evaluated by the Mattis Dementia Rating Scale (MDRS). The EGF and FGF-2 were measured by using multiplex assay for LUMINEX platform. There were also no significant differences between the patient group in terms of plasma levels of EGF and FGF-2 when compared to the HC group. There were not any significant correlations between plasma levels of EGF or FGF2 and MDRS total or individual scores in patient group and HC. There were significant correlations between plasma levels of EGF and FGF2 in both patient group and HC. Further study on plasma levels of EGF and FGF2 should be implemented in larger samples in elderly with MDD.

The Molecular Intersection Between Senescence and Major Depression in the Elderly

Major depressive disorder in the elderly-or late-life depression (LLD)-is one of the most common mental illnesses in the aging population. LLD has several negative effects on health and well-being. Individuals with LLD have an elevated risk of chronic and persistent depressive symptoms as well as high rates of treatment resistance. They also have a higher risk of developing cognitive impairment with progression to dementia and higher rates of medical comorbidity, frailty, and mortality. The mechanisms linking LLD to these adverse health outcomes are not well understood. In this article, we review the evidence that individuals with LLD present with, i.e., enhanced molecular and cellular senescent changes, focusing on the senescence-associated secretory phenotype (SASP). We then propose a mechanistic model linking SASP to the greater risk of negative health outcomes in this population. We finally provide evidence that SASP-and cellular senescence in general-can be a therapeutic target for mitigating the risk of these negative outcomes in LLD.

Oxidative stress markers imbalance in late-life depression

BACKGROUND

Oxidative stress has been implicated in the pathophysiology of mood disorders in young adults. However, there is few data to support its role in the elderly. The primary aim of this study was to evaluate whether subjects with late-life depression (LLD) presented with changes in oxidative stress response in comparison with the non-depressed control group. We then explored how oxidative stress markers associated with specific features of LLD, in particular cognitive performance and age of onset of major depressive disorder in these individuals.

METHODS

We included a convenience sample of 124 individuals, 77 with LLD and 47 non-depressed subjects (Controls). We measure the plasma levels of 6 oxidative stress markers: thiobarbituric acid reactive substances (TBARS), protein carbonil content (PCC), free 8-isoprostane, glutathione peroxidase (GPx) activity, glutathione reductase (GR) activity, and glutathione S-transferase (GST) activity.

RESULTS

We found that participants with LLD had significantly higher free 8-isoprostane levels (p = 0.003) and lower glutathione peroxidase activity (p = 0.006) compared to controls. Free 8-isoprostane levels were also significantly correlated with worse scores in the initiation/perseverance (r = -0.24, p = 0.01), conceptualization (r = -0.22, p = 0.02) sub-scores, and the total scores (r = -0.21, p = 0.04) on the DRS.

CONCLUSIONS

Our study provides robust evidence of the imbalance between oxidative stress damage, in particular lipid peroxidation, and anti-oxidative defenses as a mechanism related to LLD, and cognitive impairment in this population. Interventions aiming to reduce oxidative stress damage can have a potential neuroprotective effect for LLD subjects.

Allostatic load as a predictor of grey matter volume and white matter integrity in old age: The Whitehall II MRI study

The allostatic load index quantifies the cumulative multisystem physiological response to chronic everyday stress, and includes cardiovascular, metabolic and inflammatory measures. Despite its central role in the stress response, research of the effect of allostatic load on the ageing brain has been limited. We investigated the relation of mid-life allostatic load index and multifactorial predictors of stroke (Framingham stroke risk) and diabetes (metabolic syndrome) with voxelwise structural grey and white matter brain integrity measures in the ageing Whitehall II cohort (N = 349, mean age = 69.6 (SD 5.2) years, N (male) = 281 (80.5%), mean follow-up before scan = 21.4 (SD 0.82) years). Higher levels of all three markers were significantly associated with lower grey matter density. Only higher Framingham stroke risk was significantly associated with lower white matter integrity (low fractional anisotropy and high mean diffusivity). Our findings provide some empirical support for the concept of allostatic load, linking the effect of everyday stress on the body with features of the ageing human brain.

The association between insulin resistance, metabolic variables, and depressive symptoms in Mexican-American elderly: A population-based study

OBJECTIVE

Depressive symptoms are common among older adults with obesity and diabetes. Nonetheless, the mechanisms for this association are not clear but may involve changes in the insulin cascade signaling. We aimed to investigate the association, and potential mediators, between obesity, insulin resistance, and depressive symptoms among older adults from a homogenous cohort of Mexican-Americans.

METHODS

We included a total of 500 Mexican-American older adults assessed in the Cameron County Health Study. We evaluated depressive symptoms using the Center for Epidemiologic Survey Depression Scale (CES-D). Central obesity was defined by waist circumference. Insulin resistance was evaluated by the HOMA-IR index. We estimated the association between obesity, insulin resistance, and depressive symptoms by carrying out univariate and multivariate regression analyses.

RESULTS

In unadjusted regression analysis, HOMA-IR (unstandardized β = 0.31 ± 0.12, P = 0.007), waist circumference (unstandardized β = 0.066 ± 0.0.028, P = 0.017), and Hb1Ac levels (unstandardized β = 0.52 ± 0.24, P = 0.03) were significantly associated with CES-D scores. The association of HOMA-IR and CES-D remained statistically significant after controlling for socio-demographic and clinical variables in multivariate analysis (unstandardized β = 0.28 ± 0.11, P = 0.01).

CONCLUSION

Our results suggest that depressive symptoms are associated with insulin resistance in older Mexican-American adults. In addition, poorer glucose control and obesity are important mediators of this relationship. Additional studies are needed to evaluate whether interventions that increase insulin sensitivity can also reduce depressive symptoms in this population.

Machine Learning Approaches for Clinical Psychology and Psychiatry

Machine learning approaches for clinical psychology and psychiatry explicitly focus on learning statistical functions from multidimensional data sets to make generalizable predictions about individuals. The goal of this review is to provide an accessible understanding of why this approach is important for future practice given its potential to augment decisions associated with the diagnosis, prognosis, and treatment of people suffering from mental illness using clinical and biological data. To this end, the limitations of current statistical paradigms in mental health research are critiqued, and an introduction is provided to critical machine learning methods used in clinical studies. A selective literature review is then presented aiming to reinforce the usefulness of machine learning methods and provide evidence of their potential. In the context of promising initial results, the current limitations of machine learning approaches are addressed, and considerations for future clinical translation are outlined.

Plasma IL-17A levels in patients with late-life depression

Objective:

A consistent body of research has confirmed that patients with major depressive disorder (MDD) have increased concentrations of pro-inflammatory cytokines, including IL-6, TNF-α, IL-1β, the soluble IL-2 receptor, and C-reactive protein, compared to controls; however, there is limited information on IL-17A in MDD. Moreover, information about IL-17A in older populations, i.e., patients with late-life depression (LLD), is conspicuously missing from the literature. The purpose of this study was to investigate the role of IL-17A in LLD.

Methods:

A convenience sample of 129 individuals, 74 with LLD and 55 non-depressed controls, were enrolled in this study. The Mann-Whitney U test was used to compare plasma IL-17A levels between LLD and controls subjects, and Spearman’s rank order correlation was used to investigate correlation of these levels with clinical, neuropsychological, and cognitive assessments.

Results:

Plasma IL-17A levels were not statistically different between LLD patients and controls (p = 0.94). Among all subjects (LLD + control), plasma IL-17A did not correlate significantly with depressive symptoms (rho = -0.009, p = 0.92) but a significant correlation was observed with cognitive assessments (rho = 0.22, p = 0.01).

Conclusion:

Our findings do not support an association between plasma IL-17A levels and LLD. Nevertheless, IL-17A may be associated with cognitive impairment in LLD patients. If this finding is confirmed in future longitudinal studies, modulation of the T-helper 17 cell (T_h17) immune response may be a treatment target for cognitive impairment in this population.