Inflammation in older subjects with early- and late-onset depression in the NESDO study: a cross-sectional and longitudinal case-only design

Does depression in mid-life predispose to greater cognitive decline in later life in the Whitehall II cohort?

BACKGROUND

Later-life depression appears to have different symptomatology and possibly underlying pathology to younger adults. Depression is linked to dementia but whether it is a risk factor or an early sign of dementia remains unclear. Neuroinflammation is increasingly recognised in both conditions.

AIMS

To investigate the link between depression, inflammation and dementia. We hypothesised that recurrent depression increases the rate of cognitive decline in older adults and that this effect is modified by anti-inflammatory medication.

METHODS

We used data from Whitehall II including cognitive test results and reliable measures to assess depression. Depression was defined as a self-reported diagnosis or a score of ≥20 on the CESD. The presence/absence of inflammatory illness was assessed using a standardised list of inflammatory conditions. Individuals with dementia, chronic neurological and psychotic conditions were excluded. Logistic and linear regression was used to examine the effect of depression on cognitive test performance and the effect of chronic inflammation.

LIMITATIONS

Lack of clinical diagnoses of depression.

RESULTS

There were 1063 individuals with and 2572 without depression. Depression did not affect deterioration in episodic memory, verbal fluency or the AH4 test at 15-year follow up. We found no evidence of an effect of anti-inflammatory medication. Depressed individuals had worse cross-sectional performance on the Mill Hill test and tests of abstract reasoning and verbal fluency at both baseline and 15-year follow-up.

CONCLUSIONS

Using a UK based study with a long follow-up interval we have shown that depression in individuals aged >50 is not associated with increased cognitive decline.

[Prognosis of late-life depression: clinical and immunological features]

OBJECTIVE

To study the outcomes of depression at a late age during a 3-year prospective follow-up in patients with various immunophenotypes.

MATERIAL AND METHODS

A cohort of patients with depressive disorders who were treated in a gerontopsychiatric hospital and re-examined after 1 and 3 years. The group with immunophenotype A (with increased activity of leukocyte elastase (LE) and complex depressions, comorbid with anxiety and senesto-hypochondriac disorders) included 20 people: 6 men (30%) and 14 women (70%), median age was 68 years. A depressive episode (DE) was diagnosed in 13 patients (65%) with recurrent depressive disorder (RDD) and in 7 patients (35%) with bipolar affective disorder (BAD). The group with immunophenotype B (with reduced activity of LE and prolonged apathetic-adynamic depression) included 31 people: 10 men (32.3%) and 21 women (67.7%), the median age was 68 years. DE was diagnosed in 20 patients (64.5%) with RDD, 9 patients (29%) with BAD, and in 2 patients (6.5%) with a single DE. The patients were examined using clinical, psychometric, immunological and clinical- follow-up methods (after 1 and 3 years).

RESULTS

More favorable course of the disease with the formation of high-quality remission was observed in patients with immunophenotype A (95% of cases after 1 and 3 years; χ2=10.44; p=0.001 and χ2=11.97; p=0.001, respectively). In patients with immunophenotype B, an unfavorable course of the disease prevailed (83.9 and 87.1% of cases after 1 and 3 years) with the formation of low-quality remissions (with residual depressive disorders, the development of repeated depressive phases and chronification of depression).

CONCLUSION

The study revealed the relationship between clinical and biological features and the course of late-life depression.

Recurrent depression has persistent effects on cognition but this does not appear to be mediated by neuroinflammation

BACKGROUND

Later-life depression appears to be different to depression in younger adults. The underlying pathology may also differ. Depression is linked to dementia but whether it is a risk factor or an early sign of a developing dementia remains unclear. Neuroinflammation is increasingly recognised in both depression and Alzheimer's Disease.

AIMS

To investigate the link between depression, inflammation and dementia. We hypothesised that recurrent depression has adverse effects on performance in cognitive tests in middle to older age and that this effect is modified by anti-inflammatory medication.

METHODS

We identified UK based cohort studies which included individuals aged >50, had medical information, results from detailed cognitive testing and had used reliable measures to assess depression. Individuals with recurrent depression had ≥ 2 episodes of depression. Controls had no history of depression. The presence/absence of inflammatory illness was assessed using a standardised list of inflammatory conditions. Individuals with dementia, chronic neurological and psychotic conditions were excluded. Logistic and linear regression were used to examine the effect of depression on cognitive test performance and the mediating effect of chronic inflammation.

RESULTS

Unexpectedly in both studies there was evidence that those with recurrent depression performed better in some cognitive tasks (e.g Mill Hill vocabulary) but worse in others (e.g. reaction time). In UK Biobank there was no evidence that anti-inflammatories moderated this effect.

LIMITATIONS

Cross-sectional assessment of cognition.

CONCLUSIONS

Although previous recurrent depression has small effects on cognitive test performance this does not appear to be mediated by chronic inflammatory disease.

Cerebrospinal Fluid Proteome Alterations Associated with Neuropsychiatric Symptoms in Cognitive Decline and Alzheimer's Disease

Although neuropsychiatric symptoms (NPS) are common and severely affect older people with cognitive decline, little is known about their underlying molecular mechanisms and relationships with Alzheimer’s disease (AD). The aim of this study was to identify and characterize cerebrospinal fluid (CSF) proteome alterations related to NPS. In a longitudinally followed-up cohort of subjects with normal cognition and patients with cognitive impairment (MCI and mild dementia) from a memory clinic setting, we quantified a panel of 790 proteins in CSF using an untargeted shotgun proteomic workflow. Regression models and pathway enrichment analysis were used to investigate protein alterations related to NPS, and to explore relationships with AD pathology and cognitive decline at follow-up visits. Regression analysis selected 27 CSF proteins associated with NPS. These associations were independent of the presence of cerebral AD pathology (defined as CSF p-tau181/Aβ1−42 > 0.0779, center cutoff). Gene ontology enrichment showed abundance alterations of proteins related to cell adhesion, immune response, and lipid metabolism, among others, in relation to NPS. Out of the selected proteins, three were associated with accelerated cognitive decline at follow-up visits after controlling for possible confounders. Specific CSF proteome alterations underlying NPS may both represent pathophysiological processes independent from AD and accelerate clinical disease progression.

A 6-year prospective clinical cohort study on the bidirectional association between frailty and depressive disorder

INTRODUCTION

Depressive disorder has been conceptualised as a condition of accelerated biological ageing. We operationalised a frailty index (FI) as marker for biological ageing aimed to explore the bidirectional, longitudinal association between frailty and either depressive symptoms or depressive disorder.

METHODS

A cohort study with 6-year follow-up including 377 older (≥60 years) outpatients with a DSM-IV-defined depressive disorder and 132 never-depressed controls. Site visits at baseline, 2 and 6-year follow-up were conducted and included the CIDI 2.0 to assess depressive disorder and relevant covariates. Depressive symptom severity and mortality were assessed every 6 months by mail and telephone. A 41-item FI was operationalised and validated against the 6-year morality rate by Cox regression (HR_FI  = 1.04 [95% CI: 1.02-1.06]).

RESULTS

Cox regression showed that a higher FI was associated with a lower chance of remission among depressed patients (HR_FI  = 0.98 [95% CI: 0.97-0.99]). Nonetheless, this latter effect disappeared after adjustment for baseline depressive symptom severity. Linear mixed models showed that the FI increased over time in the whole sample (B[SE] = 0.94 (0.12), p < .001) with a differential impact of depressive symptom severity and depressive disorder. Higher baseline depressive symptom severity was associated with an attenuated and depressive disorder with an accelerated increase of the FI over time.

CONCLUSIONS

The sum score of depression rating scales is likely confounded by frailty. Depressive disorder, according to DSM-IV criteria, is associated with accelerated biological ageing. This argues for the development of multidisciplinary geriatric care models incorporating frailty to improve the overall outcome of late-life depression.

Difficulties in psychosocial functioning due to current depressive symptoms: What can C-Reactive protein tell us?

Background

Multiple empirical studies and meta-analyses have examined how inflammation may be associated with various aspects of major depression, with older adults being particularly at risk for the effects of inflammation-related depression. Despite this wide area of research, no study has examined how depression-related inflammation impacts psychosocial functioning.

Methods

Data from the National Health and Nutrition Examination Survey, years 2007–2008, were utilized to examine whether adults over the age of 40 experienced difficulty in their work, taking care of things at home, or getting along with other people due to current depressive symptoms through a logistic regression analysis. We selected C-reactive protein (CRP), a common marker of immune system activation, as our primary predictor of interest while controlling for relevant covariates.

Results

Greater CRP was positively associated with a greater risk for individuals experiencing difficulties in psychosocial functioning due to depressive symptoms. While current number and severity of depressive symptoms was also found to be significant in the model, comparison of effect sizes identified that CRP appears to be a more relevant marker for experiencing difficulty than a number of relevant biopsychosocial covariates.

Conclusion

Inflammation as measured by CRP may be a helpful tool in understanding how depressive symptoms are associated with an individual's ability to successfully navigate their social environment. Results here demonstrate the emerging utility of CRP in helping to assess the risk for negative outcomes in those experiencing depressive symptoms, especially as it pertains to older adults.

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Aimed to evaluate the role of CRP in psychosocial functioning of older adults experiencing current depressive symptoms.

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Higher CRP levels were positively associated with risk for experiencing psychosocial difficulty due to depressive symptoms.

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CRP levels above 10 mg/L were associated with a 13.7–55.6% increased risk for experiencing psychosocial difficulties.

Interleukin-10 level is associated with post-stroke depression in acute ischaemic stroke patients

BACKGROUND

Interleukin-10 (IL-10) is a pathophysiological factor in acute ischaemic stroke (AIS) and is relevant to mood disorders after stroke. We evaluated the predictive value of IL-10 in patients with post-stroke depression (PSD).

METHODS

A total of 350 stroke patients were recruited at baseline, and 151 AIS patients were screened and completed a 1-month follow-up. Serum IL-10 levels were measured within 24 h of admission. We used the 17-item Hamilton Depression Scale (HAMD-17) to evaluate depression symptoms; PSD was defined as an HAMD score ≥ 7.

RESULTS

Fifty-one (33.8%) patients showed a more serious stroke degree, larger infarction volume, and poorer daily life activities and prognosis (P < 0.05) and were diagnosed with PSD at the 1-month follow-up. Their IL-10 level decreased significantly compared to the non-PSD group (P < 0.001). After adjusting for confounders, IL-10 could be used as an independent predictor for PSD with an adjusted odds ratio (OR) of 0.615 (95% CI 0.410-0.923, P = 0.019). In addition, the optimal cut-off value of IL-10 was 0.615 pg/mL based on an area under the receiver operating characteristic curve of 0.692 (95% CI 0.604-0.781, P < 0.001), demonstrating that IL-10 could predict the occurrence of PSD. Moreover, IL-10 was an indicator of stroke severity, living ability, and functional outcomes (P < 0.05).

LIMITATIONS

IL-10 was only measured upon admission; dynamic changes need to be further monitored. This was also a single-centre study with a relatively small sample.

CONCLUSIONS

Lower IL-10 levels may be used to predict PSD.

Major Depressive Disorder in Older Patients as an Inflammatory Disorder: Implications for the Pharmacological Management of Geriatric Depression

Depression is a common and highly disabling condition in older adults. It is a heterogenous disorder and there is emerging evidence of a link between inflammation and depression in older patients, with a possible inflammatory subtype of depression. Persistent low-level inflammation, from several sources including psychological distress and chronic disease, can disrupt monoaminergic and glutaminergic systems to create dysfunctional brain networks. Despite the evidence for the role of inflammation in depression, there is insufficient evidence to recommend use of any putative anti-inflammatory agent in the treatment of depression in older adults at this stage. Further characterisation of markers of inflammation and stratification of participants with elevated rates of inflammatory markers in treatment trials is needed.

Clinical characteristics of late-life depression predicting mortality

OBJECTIVE

Depression has been associated with increased mortality rates, and modifying mechanisms have not yet been elucidated. We examined whether specific subtypes or characteristics of late-life depression predict mortality.

METHODS

A cohort study including 378 depressed older patients according to DSM-IV criteria and 132 never depressed comparisons. The predictive value of depression subtypes and characteristics on the six-year mortality rate, as well as their interaction with somatic disease burden and antidepressant drug use, were studied by Cox proportional hazard analysis adjusted for demographic and lifestyle characteristics.

RESULTS

Depressed persons had a higher mortality risk than non-depressed comparisons (HR = 2.95 [95% CI: 1.41-6.16], p = .004), which lost significance after adjustment for age, sex, education, smoking, alcohol, physical activity, number of prescribed medications and somatic comorbidity. Regarding depression subtypes and characteristics, only minor depression was associated with a higher mortality risk when adjusted for confounders (HR = 6.59 [95% CI: 1.79-24.2], p = .005).

CONCLUSIONS

Increased mortality rates of depressed older persons seem best explained by unhealthy lifestyle characteristics and multiple drug prescriptions. The high mortality rate in minor depression, independent of these factors, might point to another, yet unknown, pathway towards mortality for this depression subtype. An explanation might be that minor depression in later life reflects depressive symptoms due to underlying aging-related processes, such as inflammation-based sickness behavior, frailty, and mild cognitive impairment, which have all been associated with increased mortality.

Reduced Plasma Levels of α-Klotho and Their Correlation With Klotho Polymorphisms in Elderly Patients With Major Depressive Disorders

Background: Recent literature suggests that α-Klotho, a widely recognized anti-aging protein, is involved in longevity as well as in many diseases, including Alzheimer's disease, and depression. Although the Klotho gene encodes α-Klotho, a single transmembrane protein with intracellular and extracellular domains, the relationship between Klotho gene polymorphism and circulating α-Klotho levels in patients with major depressive disorder (MDD) is not clear. Methods: A total of 144 MDD patients and 112 age-matched healthy controls were included in this study. The Klotho genetic polymorphisms (rs9536314, rs9527025, and rs9315202) and plasma α-Klotho levels were measured by PCR and ELISA, respectively. The severity of depressive symptoms was estimated using the Hamilton Depression Scale (HAMD). Results: We found a significantly lower level of plasma α-Klotho in the MDD patients than in controls. Among them, only elderly MDD patients (first episode) showed significantly lower α-Klotho levels than the age-matched controls, while elderly recurrent and young MDD patients showed no difference in plasma α-Klotho levels from age-matched controls. The young MDD group showed a significantly earlier onset age, higher plasma α-Klotho levels, and lower HAMD scores than those in the elderly MDD group. While the plasma α-Klotho levels were higher in rs9315202 T alleles carrier regardless age or sex, the rs9315202 T allele was negatively correlated with disease severity only in the elderly MDD patients. Conclusion: The results of our study showed that only elderly MDD patients showed a decrease in plasma α-Klotho levels along with an increase in disease severity as well as an association with the number of rs9315202 T alleles, and not young MDD patients compared to age-matched controls. Our data suggest that circulating α-Klotho levels combined with Klotho genetic polymorphisms are important in elderly MDD patients, particularly carriers of the Klotho gene rs9315202 T allele.

How advances in epidemiology are influencing older adult psychiatry

Shortcomings of randomised controlled clinical trials include their high cost, which often precludes very long-term studies and very large populations, and ethical constraints of randomisation. Observational studies are a valuable alternative and we outline their use in epidemiological research to study very long-term effects of lifestyle and medication on dementia, to explore (using Mendelian randomisation) the association between Alzheimer's dementia and individual traits, and to evaluate population-wide health inequalities and lifespan changes in risk factors for psychiatric illness.

Depressive disorders in the elderly and dementia: An update

The relationship between depressive disorders in the elderly and dementia, particularly Alzheimer’s disease (AD), is highly complex. While the nature of this relationship is still a matter of debate, differential diagnosis and treatment remain a great clinical challenge. We review recent findings on the conundrum of depressive disorders in the elderly and AD. There is a biological continuum between depressive disorders in the elderly – or at least a subgroup of them – and AD. While elderly subjects with depression and patients with AD exhibit higher circulating levels of pro-inflammatory molecules and lower BDNF than matched controls, CSF levels of Aβ42 can discriminate AD from depressive disorders in the elderly. The role of antidepressant treatment as a strategy to minimize the risk of AD remains to be established.

Age-related macular degeneration: A two-level model hypothesis

Age-related diseases, including age-related macular degeneration (AMD), are of growing importance in a world where population ageing has become a dominant global trend. Although a wide variety of risk factors for AMD have been identified, age itself remains by far the most important risk factor, making it an urgent priority to understand the connections between underlying ageing mechanisms and pathophysiology of AMD. Ageing is both multicausal and variable, so that differences between individuals in biological ageing processes are the focus of a growing number of pathophysiological studies seeking to explain how ageing contributes to chronic, age-related conditions. The aim of this review is to integrate the available knowledge on the pathophysiology of AMD within the framework of the biology of ageing. One highly significant feature of biological ageing is systemic inflammation, which arises as a second-level response to a first level of molecular damage involving oxidative stress, mutations etc. Combining these insights, the various co-existing pathophysiological explanations in AMD arrange themselves according to a two-level hypothesis. Accordingly, we describe how AMD can be considered the consequence of age-related random accumulation of molecular damage at the ocular level and the subsequent systemic inflammatory host response thereof. We summarize evidence and provide original data to enlighten where evidence is lacking. Finally, we discuss how this two-level hypothesis provides a foundation for thoughts and future studies in prevention, prognosis, and intervention.

Inflammatory and metabolic disturbances are associated with more severe trajectories of late-life depression

Late-life depression is a highly prevalent mental health condition with devastating consequences even from its earliest stages. Alterations in physiological functions, such as inflammatory and metabolic, have been described in patients with depression. However, little is known on the association between depression symptom course and metabolic and inflammation dysregulation. This study aimed to depict the course of depression symptoms while ageing, taking into consideration inter-individual heterogeneity. Moreover, it intended to study the associations between inflammatory and metabolic risk profiles and symptom trajectories. To do so, data from 13,203 adults aged 50-90 years (52.75% women; mean age at baseline = 65.07, SD = 10.00) were used. Blood sample and blood pressure measures were taken from 1536 participants (56.58% women; mean age at baseline = 61.73 years, sd = 7.64). Depression symptoms were assessed every two years across a 10-year follow-up. Trajectories were identified by means of latent class mixed modelling. Inflammation and metabolic risk profile scores were obtained from plasma and diagnostic-based indicators in the follow-up, using a robust latent-factor approach. Multigroup modelling was used to study the associations between the profiles and symptom trajectories. As a result, three heterogeneous trajectories of symptoms were identified (low-symptom, moderate-symptom and high-symptom trajectory). Participants depicting a high-symptom trajectory showed the greatest inflammation profile score and high metabolic risk. Moderate-symptom trajectory was also related to high inflammation and metabolic risk. To sum up, at-risk trajectories of symptoms were associated with high inflammation and risk of metabolic diseases. This study provides valuable evidence to advance personalised medicine and mental health precision, considering person-specific profiles and physiological concomitants.

The Role of Oxidative Stress in Common Risk Factors and Mechanisms of Cardio-Cerebrovascular Ischemia and Depression

The public health sector faces a huge challenge as a result of the high prevalence and burden of disability caused by ischemic cardio-cerebrovascular disease (CVD) and depression. Although studies have explored the underlying mechanisms and potential therapies to address conditions, there is no treatment breakthrough, especially for depression which is highly influenced by social stressors. However, accumulating evidence reveals that CVD and depression are correlated and share common risk factors, particularly obesity, diabetes, and hypertension. They also share common mechanisms, including oxidative stress (OS), inflammation and immune response, cell death signaling pathway, and microbiome-gut-brain axis. This review summarizes the relationship between ischemic CVD and depression and describes the interactions among common risk factors and mechanisms for these two diseases. In addition, we propose that OS mediates the crosstalk between these diseases. We also reveal the potential of antioxidants to ameliorate OS-related injuries.

Interleukin-6 and Interleukin-10 in mood disorders: A population-based study

OBJECTIVE

The aim of this study was to assess if cytokines levels (IL-6 and IL-10) are related to major depressive disorder (MDD) and bipolar disorder (BD), in a population-based study.

METHODS

This was a cross-sectional study population-based, involving 1037 people aged 18-35. MDD, BD, anxiety and suicide risk were assessed using the Mini International Neuropsychiatric Interview. Serum IL-6 and IL-10 were measured by ELISA using a commercial kit.

RESULTS

The total sample comprised 1034 young adults, being 14.4% with MDD and 13.7% with BD. MDD and BD groups showed significantly higher serum IL-6 levels (p ≤ 0.001) and IL-10 levels (p ≤ 0.001) when compared to healthy control group. No correlation was found between serum IL-6 and IL-10 levels in health control group (p = 0.830; r = -0.008), non-suicide risk (p = 0.337; r = 0.032) and non-anxiety disorder (p = 0.375; r = 0.031). Covariance analysis showed that mood disorders alone, increase both interleukin levels (IL-6, p = 0.019; and IL-10, p = 0.026), whilst the interaction of mood disorders and suicide risk or anxiety disorders did not.

CONCLUSION

Our results suggest that inflammatory dysregulation may be involved in the physiopathology of mood disorders and serum IL-6 and IL-10 levels are putative biomarkers for these disorders.