Abstract Studies over the last 20 years have demonstrated that increased inflammation and hyperactivity of the hypothalamic–pituitary–adrenal (HPA) axis are two of the most consistent biological ...findings in major depression and are often associated: but the molecular and clinical mechanisms underlying these abnormalities are still unclear. These findings are particularly enigmatic, especially considering the accepted notion that high levels of cortisol have an anti-inflammatory action, and therefore the coexistence of inflammation and hypercortisolemia in the same diagnostic group appears counter-intuitive. To celebrate the 2015 Anna-Monika Foundation Award to our laboratory, this review will discuss our own 20 years of research on the clinical and molecular evidence underlying the increased inflammation in depression, especially in the context of a hyperactive HPA axis, and discuss its implications for the pathogenesis and treatment of this disorder.
•Patients depression have higher CSF levels of IL-6 and TNF-α than controls.•Patients with depression have higher PET TSPO expression in different brain regions.•Post-mortem data suggest a reduction ...in astrocytes and oligodendrocytes in depression.•There is little correlation between central and peripheral markers of inflammation.
Increased peripheral inflammation has been consistently reported in patients with major depressive disorder (MDD). However, only few studies have explored markers of central (brain) inflammation in patients with MDD.
The aim of this study is to systematically review in vivo and post-mortem markers of central inflammation, including studies examining cerebrospinal fluid (CSF), positron emission tomography, and post-mortem brain tissues in subjects suffering with MDD compared with controls.
PubMed and Medline databases were searched up to December 2018. We included studies measuring cerebrospinal fluid (CSF) cytokines and chemokines, positron emission tomography (PET) studies; and post-mortem studies measuring cytokines, chemokines and cell-specific markers of microglia and astrocytes, all in MDD. A meta-analysis was performed only for CSF and PET studies, as studies on post-mortem markers of inflammation had different cell-specific markers and analysed different brain regions.
A total of 69 studies met the inclusion criteria. CSF levels of IL-6 and TNF-α were higher in patients with MDD compared with controls (standardised mean difference SMD 0.37, 95%CI: 0.17–0.57 and SMD 0.58, 95%CI 0.26–0.90, respectively). CSF levels of IL-6 were increased in suicide attempters regardless of their psychiatric diagnosis. Translocator protein, a PET marker of central inflammation, was elevated in the anterior cingulate cortex and temporal cortex of patients with MDD compared with controls (SMD 0.78, 95%CI: 0.41–1.16 and SMD 0.52, 95%CI: 0.19–0.85 respectively). Abnormalities in CSF and PET inflammatory markers were not correlated with those in peripheral blood. In post-mortem studies, two studies found increased markers of microglia in MDD brains, while four studies found no MDD related changes. Of the studies investigating expression of cell-specific marker for astrocytes, thirteen studies reported a decreased expression of astrocytes specific markers, two studies reported increased expression of astrocytes specific markers, and eleven studies did not detect any difference. Four out of six studies reported decreased markers of oligodendrocytes in the prefrontal cortex. Post-mortem brain levels of tumor necrosis alpha (TNF-α) were also found increased in MDD.
Our review suggests the presence of an increase in IL-6 and TNF-alpha levels in CSF and brain parenchyma, in the context of a possible increased microglia activity and reduction of astrocytes and oligodendrocytes markers in MDD. The reduced number of astrocytes may lead to compromised integrity of blood brain barrier with increased monocyte recruitment and infiltration, which is partly supported by post-mortem studies and by PET studies showing an increased TSPO expression in MDD.
Abstract Background Pregnancy is a time of increased vulnerability for the development of anxiety and depression. This systematic review aims to identify the main risk factors involved in the onset ...of antenatal anxiety and depression. Methods A systematic literature analysis was conducted, using PubMed, PsychINFO, and the Cochrane Library. Original papers were included if they were written in English and published between 1st January 2003 and 31st August 2015, while literature reviews and meta-analyses were consulted regardless of publication date. A final number of 97 papers were selected. Results The most relevant factors associated with antenatal depression or anxiety were: lack of partner or of social support; history of abuse or of domestic violence; personal history of mental illness; unplanned or unwanted pregnancy; adverse events in life and high perceived stress; present/past pregnancy complications; and pregnancy loss. Limitations The review does not include a meta-analysis, which may have added additional information about the differential impact of each risk factor. Moreover, it does not specifically examine factors that may influence different types of anxiety disorders, or the recurrence or persistence of depression or anxiety from pregnancy to the postpartum period. Conclusions The results show the complex aetiology of antenatal depression and anxiety. The administration of a screening tool to identify women at risk of anxiety and depression during pregnancy should be universal practice in order to promote the long-term wellbeing of mothers and babies, and the knowledge of specific risk factors may help creating such screening tool targeting women at higher risk.
Summary Perinatal mental disorders are associated with increased risk of psychological and developmental disturbances in children. However, these disturbances are not inevitable. In this Series ...paper, we summarise evidence for associations between parental disorders and offspring outcomes from fetal development to adolescence in high-income, middle-income, and low-income countries. We assess evidence for mechanisms underlying transmission of disturbance, the role of mediating variables (underlying links between parent psychopathology and offspring outcomes) and possible moderators (which change the strength of any association), and focus on factors that are potentially modifiable, including parenting quality, social (including partner) and material support, and duration of the parental disorder. We review research of interventions, which are mostly about maternal depression, and emphasise the need to both treat the parent's disorder and help with associated caregiving difficulties. We conclude with policy implications and underline the need for early identification of those parents at high risk and for more early interventions and prevention research, especially in socioeconomically disadvantaged populations and low-income countries.
This paper describes the effects of immune genes genetic variants and mRNA expression on depression's risk, severity, and response to antidepressant treatment, through a systematic review on all ...papers published between 2000 and 2016. Our results, based largely on case-control studies, suggest that common genetic variants and gene-expression pathways are involved in both immune activation and depression. The most replicated and relevant genetic variants include polymorphisms in the genes for interleukin (IL)-1β, IL-6, IL-10, monocyte chemoattractant protein-1, tumor necrosis factor-alpha, C-reactive protein, and phospholipase A2. Moreover, increased blood cytokines mRNA expression (especially of IL-1β) identifies patients that are less likely to respond to conventional antidepressants. However, even for the most replicated findings there are inconsistent results, not only between studies, but also between the immune effects of the genetic variants and the resulting effects on depression. We find evidence that these discrepant findings may be explained, at least in part, by the heterogeneity of the depression immunophenotype, by environmental influences and gene × environment interactions, and by the complex interfacing of genetic variants with gene expression. Indeed, some of the most robust findings have been obtained in patients developing depression in the context of treatment with interferon-alpha, a widely used model to mimic depression in the context of inflammation. Further 'omics' approaches, through GWAS and transcriptomics, will finally shed light on the interaction between immune genes, their expression, and the influence of the environment, in the pathogenesis of depression.
Pariante discusses the study by Frank et al. on the increased peripheral inflammation in depression. The authors find an association between elevated depressive symptoms and increased C-reactive ...protein (CRP) that is independent of age, sex, socioeconomic position, smoking behavior, alcohol consumption, physical activity, BMI, chronic medical illnesses, and adverse childhood experiences. However, crucially, this study also helps in understanding whether this biological abnormality is relevant to all, or just some, depressed patients.
Abstract Objective People with schizophrenia show a high incidence of metabolic syndrome, which is associated with a high mortality from cardiovascular disease. The aetiology of the metabolic ...syndrome in schizophrenia is multi-factorial and may involve antipsychotic treatment, high levels of stress and unhealthy lifestyle, such as poor diet. As a poor diet can predispose to the development of metabolic abnormalities, the aims of this review are to clarify: 1) the dietary patterns of patients with schizophrenia, 2) the association of these dietary patterns with a worse metabolic profile, and 3) the possible factors influencing these dietary patterns. Methods A search was conducted on Pubmed, The Cochrane Library, Scopus, Embase, Ovid, Psychoinfo and ISI web of Knowledge from 1950 to the 1st of November 2011. 783 articles were found through the investigation of such databases. After title, abstract or full-text reading and applying exclusion criteria we reviewed 31 studies on dietary patterns and their effects on metabolic parameters in schizophrenia. Results Patients with schizophrenia have a poor diet, mainly characterized by a high intake of saturated fat and a low consumption of fibre and fruit. Such diet is more likely to increase the risk to develop metabolic abnormalities. Data about possible causes of poor diet in schizophrenia are still few and inconsistent. Conclusion Subjects with schizophrenia show a poor diet that partly accounts for their higher incidence of metabolic abnormalities. Further studies are needed to clarify the causes of poor diet and the role of dietary intervention to improve their physical health.
Highlights • An overview of the effect of inflammatory cytokines on neurogenesis. • In vitro studies were selected, including both human and animal cellular models. • Cytokines have both positive and ...negative roles on proliferation and neurogenesis. • Same cytokines differently modulate specific signalling pathways in human and animal models. • Diverse brain regions have specific proliferating and differentiating properties.
•UDCA, TUDCA and GUDCA bile acids exert anti-apoptotic, anti-oxidant and anti-inflammatory effects.•All three bile acids are beneficial in models of neurodegeneration.•GUDCA is the most effective in ...neurological models of bilirubin encephalopathy.•TUDCA is the most effective in models of depression.•TUDCA has metabolic advantages over UDCA and GUDCA.
Bile acids, mainly ursodeoxycholic acid (UDCA) and its conjugated species glycoursodeoxycholic acid (GUDCA) and tauroursodeoxycholic acid (TUDCA) have long been known to have anti-apoptotic, anti-oxidant and anti-inflammatory properties. Due to their beneficial actions, recent studies have started to investigate the effect of UDCA, GUDCA, TUDCA on the same mechanisms in pre-clinical models of neurological, neurodegenerative and neuropsychiatric disorders, where increased cell apoptosis, oxidative stress and inflammation in the brain are often observed. A total of thirty-five pre-clinical studies were identified through PubMed/Medline, Web of Science, Embase, PsychInfo, and CINAHL databases, investigating the role of the UDCA, GUDCA and TUDCA in the regulation of brain apoptosis, oxidative stress and inflammation, in pre-clinical models of neurological, neurodegenerative and neuropsychiatric disorders. Findings show that UDCA reduces apoptosis, reactive oxygen species (ROS) and tumour necrosis factor (TNF)-α production in neurodegenerative models, and reduces nitric oxide (NO) and interleukin (IL)-1β production in neuropsychiatric models; GUDCA decreases lactate dehydrogenase, TNF-α and IL-1β production in neurological models, and also reduces cytochrome c peroxidase production in neurodegenerative models; TUDCA decreases apoptosis in neurological models, reduces ROS and IL-1β production in neurodegenerative models, and decreases apoptosis and TNF-α production, and increases glutathione production in neuropsychiatric models. In addition, findings suggest that all the three bile acids would be equally beneficial in models of Huntington's disease, whereas UDCA and TUDCA would be more beneficial in models of Parkinson’s disease and Alzheimer's disease, while GUDCA in models of bilirubin encephalopathy and TUDCA in models of depression. Overall, this review confirms the therapeutic potential of UDCA, GUDCA and TUDCA in neurological, neurodegenerative and neuropsychiatric disorders, proposing bile acids as potential alternative therapeutic approaches for patients suffering from these disorders.
•Patients with depression show reduced variability in pro-inflammatory immune measures.•Patients with depression show increases in pro-inflammatory immune markers mean levels, and reductions in ...anti-inflammatory IL-4.
The magnitude and variability of cytokine alterations in depression are not clear.
To perform an up to date meta-analysis of mean differences of immune markers in depression, and to quantify and test for evidence of heterogeneity in immune markers in depression by conducting a meta-analysis of variability to ascertain whether only a sub-group of patients with depression show evidence of inflammation.
Studies that reported immune marker levels in peripheral blood in patients with depression and matched healthy controls in the MEDLINE database from inception to August 29th 2018 were examined.
Case-control studies that reported immune marker levels in peripheral blood in patients with depression and healthy controls were selected.
Means and variances (SDs) were extracted for each measure to calculate effect sizes, which were combined using multivariate meta-analysis.
Hedges g was used to quantify mean differences. Relative variability of immune marker measurements in patients compared with control groups as indexed by the coefficient of variation ratio (CVR).
A total of 107 studies that reported measurements from 5,166 patients with depression and 5,083 controls were included in the analyses. Levels of CRP (g = 0.71; 95%CI: 0.50–0.92; p < 0.0001); IL-3 (g = 0.60; 95%CI: 0.31–0.89; p < 0.0001); IL-6 (g = 0.61; 95%CI: 0.39–0.82; p < 0.0001); IL-12 (g = 1.18; 95%CI: 0.74–1.62; p < 0.0001); IL-18 (g = 1.97; 95%CI: 1.00–2.95; p < 0.0001); sIL-2R (g = 0.71; 95%CI: 0.44–0.98; p < 0.0001); and TNFα (g = 0.54; 95%CI: 0.32–0.76; p < 0.0001) were significantly higher in patients with depression. These findings were robust to a range of potential confounds and moderators. Mean-scaled variability, measured as CVR, was significantly lower in patients with depression for CRP (CVR = 0.85; 95%CI: 0.75–0.98; p = 0.02); IL-12 (CVR = 0.61; 95%CI: 0.46–0.80; p < 0.01); and sIL-2R (CVR = 0.85; 95%CI: 0.73–0.99; p = 0.04), while it was unchanged for IL-3, IL-6, IL-18, and TNF α.
Depression is confirmed as a pro-inflammatory state. Some of the inflammatory markers elevated in depression, including CRP and IL-12, show reduced variability in patients with depression, therefore supporting greater homogeneity in terms of an inflammatory phenotype in depression. Some inflammatory marker elevations in depression do not appear due to an inflamed sub-group, but rather to a right shift of the immune marker distribution.
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