Inflammatory Profiles in Depressed Adolescents Treated with Fluoxetine: An 8-Week Follow-up Open Study

Is the acquired hypothyroidism a risk factor for developing psychiatric disorders?

Hypothyroidism is a prevalent thyroid condition in which the thyroid gland fails to secrete an adequate amount of thyroid hormone into the bloodstream. This condition may develop due to genetic or acquired factors. The most frequent cause of acquired hypothyroidism is chronic autoimmune thyroiditis, also known as Hashimoto's disease. Acquired hypothyroidism is diagnosed when patients present with overt hypothyroidism (also known as clinical hypothyroidism), as they exhibit increased TSH and decreased T3 and T4 serum levels. This article examines the prevalence of psychiatric disorders among patients diagnosed with acquired hypothyroidism with or without Levothyroxine treatment. We discuss the available evidence indicating that acquired hypothyroidism may be a risk factor for psychiatric disorders, and the effectiveness of thyroid treatment in relieving psychiatric symptoms. Additionally, we provide critical details on thyroid hormone cutoff values reported in the literature, their potential clinical importance, and their correlation with psychiatric symptoms. Finally, we examined the various mechanisms by which acquired hypothyroidism can lead to depression. The high rate of comorbidity between hypothyroidism and psychiatric disorders deserves special attention, indicating the importance of consistent monitoring and timely identification of psychiatric symptoms to prevent disease exacerbation and facilitate therapeutic management. On the other hand, several mechanisms underlie the strong association between depression and acquired hypothyroidism. Deeper research into these mechanisms will allow knowledge of the pathophysiology of depression in patients with acquired hypothyroidism and will provide clues to design more precise therapeutic strategies for these patients.

Inflammation and immune system pathways as biological signatures of adolescent depression-the IDEA-RiSCo study

The biological mechanisms underlying the onset of major depressive disorder (MDD) have predominantly been studied in adult populations from high-income countries, despite the onset of depression typically occurring in adolescence and the majority of the world's adolescents living in low- and middle-income countries (LMIC). Taking advantage of a unique adolescent sample in an LMIC (Brazil), this study aimed to identify biological pathways characterizing the presence and increased risk of depression in adolescence, and sex-specific differences in such biological signatures. We collected blood samples from a risk-stratified cohort of 150 Brazilian adolescents (aged 14-16 years old) comprising 50 adolescents with MDD, 50 adolescents at high risk of developing MDD but without current MDD, and 50 adolescents at low risk of developing MDD and without MDD (25 females and 25 males in each group). We conducted RNA-Seq and pathway analysis on whole blood. Inflammatory-related biological pathways, such as role of hypercytokinemia/hyperchemokinemia in the pathogenesis of influenza (z-score = 3.464, p < 0.001), interferon signaling (z-score = 2.464, p < 0.001), interferon alpha/beta signaling (z-score = 3.873, p < 0.001), and complement signaling (z-score = 2, p = 0.002) were upregulated in adolescents with MDD compared with adolescents without MDD independently from their level of risk. The up-regulation of such inflammation-related pathways was observed in females but not in males. Inflammatory-related pathways involved in the production of cytokines and in interferon and complement signaling were identified as key indicators of adolescent depression, and this effect was present only in females.

The relationship between serum resolvin D1, NLRP3, cytokine levels, and adolescents with first-episode medication-naïve major depressive disorder

BACKGROUND

Inflammation has become a critical pathological mechanism of Major Depressive Disorder (MDD). NLRP3 is a critical inflammatory pathway to maintain the immune balance. Recently, preclinical evidence showed that Resolvin D1 might potentially offer a new option for antidepressant treatment due to its protective effects through the inhibition of neuroinflammation. However, whether they have clinical value in the diagnosis and treatment evaluation of adolescent depression was unclear.

METHODS

Forty-eight untreated first-episode adolescent patients with moderate to severe major depressive disorder, as well as 30 healthy adolescents (HCs, age and gender-matched), were enrolled for this study. Their ages ranged from 13 to 18 (15.75 ± 1.36) years. The patients were treated with fluoxetine for 6-8 weeks. HDRS-17 was used to evaluate the severity of depressive symptoms. Venous blood samples were collected at baseline for the two groups and at the time-point of post-antidepressant treatment for the patients. Serum concentrations of RvD1, NLRP3, IL-1β, IL-18, and IL-4 were measured by enzyme-linked immunosorbent assays (ELISA) pre- and post-fluoxetine treatment.

RESULTS

Serum levels of RvD1 and anti-inflammatory cytokine IL-4 were significantly elevated in adolescents with MDD compared to healthy adolescents, but no significant difference in NLRP3, IL-1β, and IL-18 between the two groups. Meanwhile, RvD1 (positively) and IL-4 (negatively) were correlated with the severity of symptoms (HDRS-17 scores) after adjusting age, gender, and BMI. Interestingly, fluoxetine treatment significantly reduced the serum levels of RvD1, NLRP3, IL-1β, and IL-18 in MDD adolescents but increased the levels of IL-4 relative to baseline. Furthermore, we observed that serum levels of RvD1 might be an excellent distinguishing indicator for depression and healthy adolescents.

CONCLUSIONS

Our study is the first to compare RvD1 and NLRP3 between adolescent MDD and HCs. Our findings of reactive increase of RvD1 in adolescent MDD comprised a novel and critical contribution. Our results showed the presence of inflammation resolution unbalanced in adolescents with MDD and indicated that RvD1 might be an ideal biomarker for diagnosing and treating adolescent MDD.

Impacts of inflammatory cytokines on depression: a cohort study

BACKGROUND

Inflammatory factors are associated with depression. We seek to investigate the correlation between inflammatory cytokines and prognosis of depression or suicidal ideation and behavior at 3 months in depression patients.

METHODS

Eighty-two depressed outpatients were recruited and treated as usual. Plasma cytokines were measured at baseline. Patients were followed up with Patient Health Questionnaire-9 and suicidal ideation and behavior according to the item 3 of Hamilton depression scale for 3 months.

RESULTS

Compared to the depression patients with low level of interleukin-1β, the high one had severe depressive symptoms at month 2 and 3 (B 0.92, P < 0.01; B 0.86, P = 0.02; respectively). The incidence of suicidal ideation or behavior was 18.3% at 3 months. Depression patients with high levels of tumor necrosis factor-α showed high risk of suicidal ideation and behavior than the low one (OR 2.16, 95% CI 1.00-4.65, P = 0.04).

CONCLUSIONS

High levels of interleukin-1β and tumor necrosis factor-α were predictive of middle-term severe depressive symptoms and suicidal ideation and behavior respectively.

Pharmacological anti-inflammatory treatment in children and adolescents with depressive symptoms: A systematic-review and meta-analysis

Growing evidence suggests an association between inflammatory processes and depressive disorders (DD). DD typically emerge during adolescence. Treatment effects of agents with anti-inflammatory properties in youth DD have not been systematically reviewed. Here, the existing evidence on the use of anti-inflammatory drugs (including polyunsaturated fatty acids, nonsteroidal anti-inflammatory drugs, cytokine inhibitors, statins, pioglitazone, corticosteroids, and minocycline or modafinil) in children and adolescents with DD was synthesized using meta-analysis. The PROSPERO preregistered search yielded 22 records meeting search criteria. Of these, data from 19 primary studies (n = 1366 subjects) were subjected to meta-analysis. A significant but small effect in favor of anti-inflammatory agents in reducing depressive symptoms in youth with DD was found (SMD = -0.29, 95 % CI = -0.514; -0.063, p = 0.01). Post-hoc analyzes of drug subclasses found a significant effect of omega-3 fatty acids in reducing depressive symptoms. Results underline the importance to consider inflammatory pathways in the supplemental treatment of youth with DD. Further research is warranted, to clarify if anti-inflammatory agents are only effective in a subpopulation of patients (inflammatory biotype of depression in youth) and/or to alleviate specific symptom domains of depression (e.g., cognitive symptoms).

Upregulation of S100A8 in peripheral blood mononuclear cells from patients with depression treated with SSRIs: a pilot study

BACKGROUND

Major depressive disorder (MDD) affects more than 350 million people worldwide, and there is currently no laboratory test to diagnose it. This pilot study aimed to identify potential biomarkers in peripheral blood mononuclear cells (PBMCs) from MDD patients.

METHODS

We used tandem mass tagging coupled to synchronous precursor selection (mass spectrometry) to obtain the differential proteomic profile from a pool of PBMCs from MDD patients and healthy subjects, and quantitative PCR to assess gene expression of differentially expressed proteins (DEPs) of our interest.

RESULTS

We identified 247 proteins, of which 133 had a fold change ≥ 2.0 compared to healthy volunteers. Using pathway enrichment analysis, we found that some processes, such as platelet degranulation, coagulation, and the inflammatory response, are perturbed in MDD patients. The gene-disease association analysis showed that molecular alterations in PBMCs from MDD patients are associated with cerebral ischemia, vascular disease, thrombosis, acute coronary syndrome, and myocardial ischemia, in addition to other conditions such as inflammation and diabetic retinopathy.

CONCLUSIONS

We confirmed by qRT-PCR that S100A8 is upregulated in PBMCs from MDD patients and thus could be an emerging biomarker of this disorder. This report lays the groundwork for future studies in a broader and more diverse population and contributes to a deeper characterization of MDD.

Investigation of the effects of oxidative stress, inflammation on the pathway of tryptophan/kynurenine in OCD

OBJECTIVES

Recent studies have shown that the distribution of the tryptophan/kynurenine pathway (KP) plays a role in the development of obsessive-compulsive disorder (OCD). We aimed to reveal the relationship between CYP1A1 rs464903 and aryl hydrocarbon receptor (AhR) rs10249788 associated with the KP and interferon gamma (IFN γ) and oxidative stress in OCD.

METHODS

In our study, the serum and DNAs of 150 samples, including 100 OCD patients and 50 controls, were used. The activity of glutathione peroxidase (GSH-Px), and the levels of IFN γ, thiobarbituric acid reactive substances (TBARS), tryptophan, and kynurenine were determined by biochemical methods. AhR rs10249788 and cytochrome P450 family CYP1A1 rs4646903, which interact directly with the KP, were analysed by polymerase chain reaction followed by restriction fragment length polymorphism. P < 0.05 was considered statistically significant.

RESULT

There were no significant differences between groups in CYP1A1 rs4646903 and AhR rs10249788 while tryptophan and IFN γ were found to be higher in controls (p < 0.001, for both), and TBARS and indolamine-2,3-dioxygenase were found to be higher in OCD (p < 0.001, for both). There were significant correlations between IFN γ and TBARS and GSH-Px (p = 0.028, p = 0.020, respectively) in the OCD group.

CONCLUSIONS

For the first time studied in OCD, it has been shown that IFN γ, tryptophan, oxidative stress parameters, and gene variants of CYP1A1 rs4646903 anAhR rs10249788 are shown effective on the KP.

A functional account of stimulation-based aerobic glycolysis and its role in interpreting BOLD signal intensity increases in neuroimaging experiments

In aerobic glycolysis, oxygen is abundant, and yet cells metabolize glucose without using it, decreasing their ATP per glucose yield by 15-fold. During task-based stimulation, aerobic glycolysis occurs in localized brain regions, presenting a puzzle: why produce ATP inefficiently when, all else being equal, evolution should favor the efficient use of metabolic resources? The answer is that all else is not equal. We propose that a tradeoff exists between efficient ATP production and the efficiency with which ATP is spent to transmit information. Aerobic glycolysis, despite yielding little ATP per glucose, may support neuronal signaling in thin (< 0.5 µm), information-efficient axons. We call this the efficiency tradeoff hypothesis. This tradeoff has potential implications for interpretations of task-related BOLD "activation" observed in fMRI. We hypothesize that BOLD "activation" may index local increases in aerobic glycolysis, which support signaling in thin axons carrying "bottom-up" information, or "prediction error"-i.e., the BIAPEM (BOLD increases approximate prediction error metabolism) hypothesis. Finally, we explore implications of our hypotheses for human brain evolution, social behavior, and mental disorders.

Changes in cytokine and cytokine receptor levels during postnatal development of the human dorsolateral prefrontal cortex

In addition to their traditional roles in immune cell communication, cytokines regulate brain development. Cytokines are known to influence neural cell generation, differentiation, maturation, and survival. However, most work on the role of cytokines in brain development investigates rodents or focuses on prenatal events. Here, we investigate how mRNA and protein levels of key cytokines and cytokine receptors change during postnatal development of the human prefrontal cortex. We find that most cytokine transcripts investigated (IL1B, IL18, IL6, TNF, IL13) are lowest at birth and increase between 1.5 and 5 years old. After 5 years old, transcriptional patterns proceeded in one of two directions: decreased expression in teens and young adults (IL1B, p = 0.002; and IL18, p = 0.004) or increased mean expression with maturation, particularly in teenagers (IL6, p = 0.004; TNF, p = 0.002; IL13, p < 0.001). In contrast, cytokine proteins tended to remain elevated after peaking significantly around 3 years of age (IL1B, p = 0.012; IL18, p = 0.026; IL6, p = 0.039; TNF, p < 0.001), with TNF protein being highest in teenagers. An mRNA-only analysis of cytokine receptor transcripts found that early developmental increases in cytokines were paralleled by increases in their ligand-binding receptor subunits, such as IL1R1 (p = 0.033) and IL6R (p < 0.001) transcripts. In contrast, cytokine receptor-associated signaling subunits, IL1RAP and IL6ST, did not change significantly between age groups. Of the two TNF receptors, the 'pro-death' TNFRSF1A and 'pro-survival' TNFRSF1B, only TNFRSF1B was significantly changed (p = 0.028), increasing first in toddlers and again in young adults. Finally, the cytokine inhibitor, IL13, was elevated first in toddlers (p = 0.006) and again in young adults (p = 0.053). While the mean expression of interleukin-1 receptor antagonist (IL1RN) was highest in toddlers, this increase was not statistically significant. The fluctuations in cytokine expression reported here support a role for increases in specific cytokines at two different stages of human cortical development. The first is during the toddler/preschool period (IL1B, IL18, and IL13), and the other occurs at adolescence/young adult maturation (IL6, TNF and IL13).

Serum cytokines-based biomarkers in the diagnosis and monitoring of therapeutic response in patients with major depressive disorder

BACKGROUND

Several lines of evidence have suggested that cytokines are implicated in the pathophysiology of depression and antidepressant treatment outcome. However, the results are not always congruent and partly contradictory. We therefore examined the serum levels of multiple cytokines in patients with major depressive disorder (MDD), with the aim to identify serum cytokines-based biomarkers for MDD diagnosis and antidepressant response.

METHODS

Fifty-nine patients with MDD and 61 healthy controls were included. The baseline levels of serum cytokines between MDD group and control group were compared, and the discriminative ability of different cytokines in predicting MDD patients from healthy controls was investigated using the receiver operating characteristic (ROC) curve method. The baseline levels of serum cytokines between antidepressant nonresponders and responders were compared, and the discriminative ability of different cytokines in predicting nonresponders from responders was evaluated using the ROC curve method.

RESULTS

Compared to controls, 15 of the 37 serum cytokines were increased, while 8 cytokines were decreased in MDD patients (all P < 0.05). The results of ROC curve showed that the Area Under Curve (AUC) values of 15 cytokines including IL-2, IL-5, IL-6, IL-8, IL-12, IL-13, IL-16, CCL3, CCL4, CCL17, CXCL10, TNF-α, TNF-β, VEGF-C, and FGF basic were greater than 0.7 in discriminating MDD patients from healthy control. Moreover, after 4-week treatment, levels of the 2 cytokines (IL-12 and TSLP) elevated at baseline significantly down-regulated, and levels of the 6 cytokines (IL-5, IL-16, CCL17, CXCL10, TNF-β, and PIGF) decreased at baseline significantly up-regulated (all P < 0.05). Furthermore, a positive relationship was found between TNF-α levels and Hamilton Depression Rating Scale-24 (HAMD-24) scores in patients with MDD at baseline (r = 0.302, P = 0.019). Additionally, compared to responders, nonresponders exhibited decreased levels of IL-1α, IL-5, IL-13, IL-15, VEGF, and ICAM-1 (all P < 0.05). The ROC curve analysis demonstrated that a combined panel of IL-1α, IL-5, and ICAM-1 achieved a high accuracy in discriminating antidepressant nonresponders from responders (AUC = 0.850, sensitivity = 83.3%, specificity = 81.8%).

CONCLUSIONS

These results suggested that alterations in peripheral cytokines levels hold significant promise as biomarkers for MDD diagnosis and antidepressant response.

Evaluation of serum interleukin-1 receptor antagonist levels in major depressive disorder: A case-control study

Background and Aims

Major depressive disorder (MDD) is characterized by the occurrence of one or more depressive episodes lasting a minimum of 2 weeks and is marked by a persistently low mood and a lack of enjoyment in daily activities. The diagnosis of MDD is not possible by a well-established laboratory test or biomarker. A wide range of potential biomarkers for depression have been proposed by many studies, but none of them has adequately described the correlation between the biomarkers and depression. The purpose of this study was to evaluate serum interleukin-1 receptor antagonist (IL-1RA) levels as an early depression risk factor.

Methods

The present case-control study included 88 participants. Among them, 44 MDD patients enrolled from the psychiatry department of a public hospital in Dhaka, Bangladesh, and 44 age- and sex-matched healthy controls (HCs) from various sites in Dhaka city. A qualified psychiatrist evaluated the cases and HCs based on the fifth edition of the diagnostic and statistical manual of mental disorders (DSM-5). The Hamilton depression (Ham-D) rating scale was employed to evaluate the intensity of depression. An enzyme-linked immunosorbent assay kit (Boster Bio, USA) was used to determine serum IL-1RA concentrations.

Results

We observed no marked alteration in the serum concentration of IL-1RA in MDD patients in comparison to HCs (292.81 ± 24.81 and 288 ± 24.87 pg/mL; p > 0.05). Among MDD patients, we found no noteworthy association between the severity of depression and serum IL-1RA levels.

Conclusion

The findings of the present study imply that IL-1RA may not be identified as a promising biomarker for risk assessment of depression. However, its neuroprotective role may be taken into consideration for the understanding of pathophysiology of MDD.

Prospective study on Maresin-1 and cytokine levels in medication-naïve adolescents with first-episode major depressive disorder

Background

Inflammation and immune activation may play a role in the pathological mechanism of Major Depressive Disorder (MDD). Evidence from cross-sectional and longitudinal studies of adolescents and adults has shown that MDD is associated with increased plasma pro-inflammatory cytokines (e.g., IL-1β, IL-6). It has been reported that Specialized Pro-resolving Mediators (SPMs) mediate inflammation resolution, and Maresin-1 can activate the process of inflammation and promote inflammation resolution by promoting macrophage phagocytosis. However, no clinical studies have been conducted to evaluate the relationship between the levels of Maresin-1 and cytokine and the severity of MDD symptomatology in adolescents.

Methods

40 untreated adolescent patients with primary and moderate to severe MDD and 30 healthy participants as the healthy control (HC) group aged between 13 and 18 years old were enrolled. They received clinical and Hamilton Depression Rating Scale (HDRS-17) evaluation and then, blood samples were collected. Patients in the MDD group were re-evaluated for HDRS-17, and blood samples were taken after a six to eight-week fluoxetine treatment.

Results

The adolescent patients with MDD had lower serum levels of Maresin-1 and higher serum levels of interleukin 6 (IL-6) compared with the HC group. Fluoxetine treatment alleviated depressive symptoms in MDD adolescent patients, which was reflected by higher serum levels of Maresin-1 and IL-4 and lower HDRS-17 scores, serum levels of IL-6, and IL-1β. Moreover, the serum level of Maresin-1 was negatively correlated with the depression severity scores on the HDRS-17.

Conclusion

Adolescent patients with primary MDD had lower levels of Maresin-1 and higher levels of IL-6 compared with the HC group, implying that the peripheral level of pro-inflammatory cytokines may be elevated in MDD, resulting in the insufficiency of inflammation resolution. The Maresin-1 and IL-4 levels increased after anti-depressant treatment, whereas IL-6 and IL-1β levels decreased significantly. Moreover, Maresin-1 level negatively correlated with depression severity, suggesting that reduced levels of Maresin-1 promoted the progression of MDD.

Potential of Capric Acid in Neurological Disorders: An Overview

To solve the restrictions of a classical ketogenic diet, a modified medium-chain triglyceride diet was introduced which required only around 60% of dietary energy. Capric acid (CA), a small molecule, is one of the main components because its metabolic profile offers itself as an alternate source of energy to the brain in the form of ketone bodies. This is possible with the combined capability of CA to cross the blood-brain barrier and achieve a concentration of 50% concentration in the brain more than any other fatty acid in plasma. Natural sources of CA include vegetable oils such as palm oil and coconut oil, mammalian milk and some seeds. Several studies have shown that CA has varied action on targets that include AMPA receptors, PPAR-γ, inflammatory/oxidative stress pathways and gut dysbiosis. Based on these lines of evidence, CA has proved to be effective in the amelioration of neurological diseases such as epilepsy, affective disorders and Alzheimer's disease. But these studies still warrant more pre-clinical and clinical studies that would further prove its efficacy. Hence, to understand the potential of CA in brain disease and associated comorbid conditions, an advance and rigorous molecular mechanistic study, apart from the reported in-vitro/in-vivo studies, is urgently required for the development of this compound through clinical setups.

[Effect of Sertraline on Serum Cytokine Levels in Adolescents With First-Episode Major Depressive Disorder]

Objective

To investigate the changes in serum inflammatory cytokines and the predictive factors for the efficacy of sertraline following medication therapy in adolescents with first-episode major depressive disorder (MDD).

Methods

A total of 61 adolescent patients with first-episode drug-naïve MDD were enrolled for the MDD group and 55 healthy adolescents were enrolled for the healthy control (HC) group. Sertraline tablets were administered to the MDD group for 8 weeks after enrollment, while no medication was given to the HC group. In the MDD group, blood samples were collected to measure the cytokine levels and clinical data, including scores for the 17-item Hamilton Depression Scale (HAMD-17) and the Connor-Davidson Resilience Scale (CD-RISC), were assessed at baseline and at the end of the 8-week medication, whereas in the HC group, blood samples and clinical data were collected only at baseline. The correlation between the levels of serum inflammatory cytokines and depression severity in the MDD group was analyzed and stepwise linear regression of HAMD-17 in the MDD group was performed to find serologic indicators that could be used to predict the efficacy of sertraline.

Results

At baseline, the levels of interleukin (IL)-1β and IL-6 in the MDD group were significantly higher than those in the HC group (all P<0.0001), while the tumor necrosis factor (TNF)-α level in the MDD group was significantly lower than that in the HC group ( P=0.006). After 8 weeks of medication treatment, the MDD group showed decreased levels of IL-1β and IL-6 and increased level of TNF-α compared to the pre-treatment levels. In addition, the HAMD-17 score, CD-RISC total score, and scores for perceived competence, trust and tolerance, and control, three factors of CD-RISC, all improved after treatment. There was no significant difference in serum cytokine levels at baseline between the subgroup showing response to the treatment and the non-responding subgroup. There was a weak correlation between IL-6 levels before and after treatment and CD-RISC scores and the scores for the trust and tolerance factor of CD-RISC before and after treatment. The baseline IL-1β and TNF-α levels did not show significant effect on posttreatment HAMD-17 scores.

Conclusions

Serum cytokine levels of adolescents with first-episode MDD differ significantly from those of healthy adolescents. Although IL-6 was found to be correlated with depression severity, there was not enough support for it to be used as a predictor of the antidepression efficacy of sertraline.

Evidence of innate immune dysfunction in first-episode psychosis patients with accompanying mood disorder

Background

Inflammation and increases in inflammatory cytokines are common findings in psychiatric disorders such as schizophrenia (SCZ), bipolar disorder (BD), and major depressive disorder (MDD). Meta-analyses of studies that measured circulating cytokines have provided evidence of innate inflammation across all three disorders, with some overlap of inflammatory cytokines such as IL-6 and TNF-α. However, differences across disorders were also identified, including increased IL-4 in BD that suggest different immune mechanisms may be involved depending on the type of disorder present.

Methods

We sought to identify if the presence or absence of an affective disorder in first-episode psychotic (FEP) patients was associated with variations in cytokine production after stimulation of peripheral blood mononuclear cells (PBMC). 98 participants were recruited and grouped into healthy controls (n = 45) and first-episode psychosis patients (n = 53). Psychosis patients were further grouped by presence (AFF; n = 22) or lack (NON; n = 31) of an affective disorder. We cultured isolated PBMC from all participants for 48 h at 37 °C under four separate conditions; (1) culture media alone for baseline, or the following three stimulatory conditions: (2) 25 ng/mL lipopolysaccharide (LPS), (3) 10 ng/mL phytohemagglutinin (PHA), and (4) 125 ng/ml α-CD3 plus 250 ng/ml α-CD28. Supernatants collected at 48 h were analyzed using multiplex Luminex assay to identify differences in cytokine and chemokine production. Results from these assays were then correlated to patient clinical assessments for positive and negative symptoms common to psychotic disorders.

Results

We found that PBMC from affective FEP patients produced higher concentrations of cytokines associated with both innate and adaptive immunity after stimulation than non-affective FEP patients and healthy controls. More specifically, the AFF PBMC produced increased tumor necrosis fctor (TNF)-α, interleukin (IL)-1β, IL-6, and others associated with innate inflammation. PBMC from AFF also produced increased IL-4, IL-17, interferon (IFN)γ, and other cytokines associated with adaptive immune activation, depending on stimulation. Additionally, inflammatory cytokines that differed at rest and after LPS stimulation correlated with Scale for the Assessment of Negative Symptoms (SANS) scores.

Conclusions

Our findings suggest that immune dysfunction in affective psychosis may differ from that of primary psychotic disorders, and inflammation may be associated with increased negative symptoms. These findings could be helpful in determining clinical diagnosis after first psychotic episode.

Innate lymphoid cells in depression: Current status and perspectives

The recent discovery of innate lymphoid cells (ILCs) has provided new insights into our understanding of the pathogenesis of many disease conditions with immune dysregulation. Type 1 innate lymphoid cells (ILC1s) induce type I immunity and are characterized by the expression of signature cytokine IFN-γ and the master transcription factor T-bet; ILC2s stimulate type II immune responses and are defined by the expression of signature cytokines IL-5 and IL-13, and transcription factors ROR-α and GATA3; ILC3s requires the transcription factor RORγt and produce IL-22 and IL-17. ILCs are largely tissue-resident and are enriched at barrier surfaces of the mammalian body. Increasing evidence shows that inflammation is involved in the pathogenesis of depression. Although few studies have directly investigated the role of ILCs in depression, several studies have examined the levels of cytokines produced by ILCs in depressed subjects. This review summarizes the potential roles of ILCs in depression. A better understanding of the biology of ILCs may lead to the development of new therapeutic strategies for the management of depression.

Peripheral blood cytokines as potential diagnostic biomarkers of suicidal ideation in patients with first-episode drug-naïve major depressive disorder

Objective

Major Depressive Disorder (MDD) is a leading cause of disability, with a high risk of suicidal ideation (SI). Few studies have evaluated the potential of multiple cytokines as biomarkers for SI in patients with MDD. In the present study, we examined the serum levels of multiple cytokines in patients with first-episode drug-naïve MDD, with the aim to discover and identify serum cytokines-based biomarkers for identification of SI in MDD.

Methods

A total of 55 patients with first-episode drug-naïve MDD were enrolled and divided into two groups: 26 MDD patients without SI and 29 MDD patients with SI. Beck Scale for Suicide Ideation was used to estimate SI. A total of 37 cytokines were measured using Multiplex Luminex Assays. The levels of serum cytokines between MDD patients without SI and MDD patients with SI were compared and diagnostic values of different cytokines were evaluated using the receiver operating characteristic (ROC) curve method for discriminating MDD patients with SI from MDD patients without SI. The relationship between the group and the abnormal cytokines were investigated in multiple linear regression models, with adjustments for age, gender, BMI, smoking, and Hamilton Depression Rating Scale-24 (HAMD-24) scores.

Results

The levels of CCL26 and VEGF in MDD patients with SI were significantly lower than those in MDD patients without SI (all P < 0.05). On the contrary, the levels of IL-17C, CXCL10, and TNF-β in MDD patients with SI were significantly higher than those in MDD patients without SI (all P < 0.05). Moreover, the results of multiple linear regression revealed that group was a significant independent predictor of serum IL-17C, CCL-26, VEGF, and TNF-β levels (all P < 0.05). In terms of CXC10, group was also likely to be a significant independent predictor (β = 0.257, P = 0.063). Furthermore, the AUC values of IL-17C and TNF-β were 0.728 and 0.732, respectively. Additionally, a combined panel of IL-17C and TNF-β achieved a high accuracy in discriminating MDD patients with SI from MDD patients without SI (AUC = 0.848, sensitivity = 75.9%, specificity = 72.7%).

Conclusions

These results suggested that circulating IL-17C and TNF-β may hold promise in the discovery of biomarkers for identification of SI in MDD.

Evaluation of Inflammatory Response System (IRS) and Compensatory Immune Response System (CIRS) in Adolescent Major Depression

Purpose

Nowadays, the role of two tightly interconnected systems, the inflammatory response system (IRS) and the compensatory immune response system (CIRS) in depression, is increasingly discussed. Various studies indicate pro-inflammatory activity in adolescent depression; however, there is an almost complete lack of findings about IRS and CIRS balance. Thus, we aimed to assess different IRS and CIRS indices, profiles, and IRS/CIRS ratios in drug-naïve MDD patients at adolescent age, with respect to sex.

Patients and Methods

One hundred MDD adolescents (40 boys, average age: 15.4±1.2 yrs.) and 60 controls (28 boys, average age: 15.3±1.5 yrs.) were examined. Evaluated parameters were 1. plasma levels of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, interferon gamma, tumor necrosis factor alpha (TNF-α), soluble receptor of IL-6 (sIL-6R), soluble receptors of TNF-α (sTNF-R1, sTNF-R2); 2. profiles: IL-6 trans-signaling, M1 macrophage signaling, helper T lymphocytes (Th) 1 profile, regulatory T lymphocytes (Treg)+Th2, allIRS, and allCIRS; 3. IRS vs CIRS activity ratios: TNF-α/TNF-R1, TNF-α/TNF-R2, TNF-α/sTNF-Rs (ie sTNF-R1+sTNF-R2), Th1/Th2, Th1/Treg, Th1/Th2+Treg, M1/Th2, M1/Treg, M1/Treg+Th2, allIRS/allCIRS.

Results

MDD patients showed increased IL-4, IL-10, TNF-α, sIL-6R, Treg+Th2, allIRS, allCIRS, and TNF-α/sTNF-Rs, and decreased Th1/Th2+Treg. MDD females showed increased IL-10 and TNF-α compared to control females. MDD males showed increased IL-4, IL-10, sIL-6R, Treg+Th2, and TNF-α/TNF-R1 compared to control males. Increased sTNF-R1 was found in MDD males compared to MDD females. Positive correlations were found between CDI score and sIL-6R and IL-10 in the total group and between CDI score and IL-10 in adolescent males.

Conclusion

Our study for the first time extensively evaluated IRS and CIRS interactions revealing enhanced pro-inflammatory TNF-α signaling and IL-6 trans-signaling in association with increased IL-10- and IL-4-mediated anti-inflammatory activity in first-episode depression at the adolescent age. Moreover, results reflect the sex-specific simultaneous activation of IRS and CIRS pathways in adolescent depression.

Cytokine alterations in pediatric internalizing disorders: Systematic review and exploratory multi-variate meta-analysis

Pediatric internalizing disorders are prevalent and characterized by a maladaptive cognitive, emotional response to a perceived stressor. The hypothesized effect of this response is observable changes in behavior mediated by homeostatic inflammatory cytokines. The aim of this study was to synthesize the literature and analyze the effect of cytokines on pediatric internalizing disorders. Influential moderating variables, including mean body mass index, fasting status at blood collection, participant sex, cytokine type, mean age, percentage of sample medicated, and diagnosis, were also assessed. A systematic literature search was performed in electronic databases (Medline, PubMed, and PsycINFO) from January 1, 1980 to June 15, 2022. Case-control studies of pediatric internalizing disorders, specifically anxiety and depression, were reviewed for their association with peripheral cytokine levels. Meta-analyses were performed using a random effects multi-variate model and effect sizes were calculated using Hedge's g for IL-2, CRP, IL-6, TNF-α, IL-1β, IFN-γ, and IL-10. Thirty-three studies were reviewed and 28 studies were included in the meta-analysis (n = 1322 cases and n = 3617 controls). Peripheral cytokine levels were elevated in pediatric internalizing disorders compared to controls (Hedge's g = 0.19, p < 0.001). In the moderator analyses, depression diagnosis (Hedge's g = 0.18, p = 0.009) and non-fasting blood collection (Hedge's g = 0.20, p = 0.006) were significant. The meta-analytic findings are limited by methodological variation between studies, high heterogeneity, and low statistical power. Despite this, the findings suggest that elevated peripheral cytokine levels may play a role in the etiology and/or symptom maintenance of pediatric internalizing disorders.

Pathophysiology of Depression: Stingless Bee Honey Promising as an Antidepressant

Depression is a debilitating psychiatric disorder impacting an individual’s quality of life. It is the most prevalent mental illness across all age categories, incurring huge socio-economic impacts. Most depression treatments currently focus on the elevation of neurotransmitters according to the monoamine hypothesis. Conventional treatments include tricyclic antidepressants (TCAs), norepinephrine–dopamine reuptake inhibitors (NDRIs), monoamine oxidase inhibitors (MAOIs), and serotonin reuptake inhibitors (SSRIs). Despite numerous pharmacological strategies utilising conventional drugs, the discovery of alternative medicines from natural products is a must for safer and beneficial brain supplement. About 30% of patients have been reported to show resistance to drug treatments coupled with functional impairment, poor quality of life, and suicidal ideation with a high relapse rate. Hence, there is an urgency for novel discoveries of safer and highly effective depression treatments. Stingless bee honey (SBH) has been proven to contain a high level of antioxidants compared to other types of honey. This is a comprehensive review of the potential use of SBH as a new candidate for antidepressants from the perspective of the monoamine, inflammatory and neurotrophin hypotheses.

Screening of SERT and p11 mRNA Levels in Airline Pilots: A Translational Approach

Airline pilots are frequently exposed to numerous flights per week, changes in their circadian rhythms, and extended periods away from home. All these stressors make pilots susceptible to developing psychiatric disorders. Recently, emphasis has been placed on the need for molecular tests that help in the diagnosis of depression. The genes SLC6A4 and S100A10 encode serotonin transporter (SERT) and p11 protein, respectively. Their expression has been frequently associated with stress and depression. In this work, we quantified, by quantitative PCR, the expression of SERT and p11 in peripheral mononuclear cells of airline pilots compared to patients with depression and healthy volunteers. Moreover, by mass spectrometry, we quantified the serum serotonin levels in the same three groups. We found that SERT and p11 were overexpressed in the mononuclear cells of airline pilots and depressed patients compared to healthy volunteers. Although serum serotonin was not different between healthy volunteers and airline pilots, a decreasing trend was observed in the latter. As expected, serum serotonin in the patients was significantly lower. Alterations in SERT and p11 in airline pilots could be related to professional stress, a condition that could potentially affect their long-term mental health.

Inflammation and depression in young people: a systematic review and proposed inflammatory pathways

Depression onset peaks during adolescence and young adulthood. Current treatments are only moderately effective, driving the search for novel pathophysiological mechanisms underlying youth depression. Inflammatory dysregulation has been shown in adults with depression, however, less is known about inflammation in youth depression. This systematic review identified 109 studies examining the association between inflammation and youth depression and showed subtle evidence for inflammatory dysregulation in youth depression. Longitudinal studies support the bidirectional association between inflammation and depression in youth. We hypothesise multiple inflammatory pathways contributing to depression. More research is needed on anti-inflammatory treatments, potentially tailored to individual symptom profiles.

Metabolic responses in the cortex and hippocampus induced by Il-15rα mutation

Metabolomics showed distinct metabolic phenotypes of the different brain regions related to the IL-15 system, enhancing our understanding of the IL-15 system and its interactions with neuropsychiatric disorders.

Linking childhood trauma and cytokine levels in depressed adolescents

BACKGROUND

Evidence supports raised circulating levels of inflammatory mediators, such as interleukin-6 (IL-6) and tumor necrosis factor (TNFα), among clinically depressed adults, although preliminary findings in adolescents are mixed. Independently, meta-analyses identify correlations between childhood trauma and elevated cytokine levels in adulthood. Here, we examine the possible role of individual differences in exposure to childhood trauma in contributing to variability in cytokine levels in depressed adolescents.

METHODS

52 depressed adolescents and 20 healthy adolescents completed measures of childhood trauma and provided blood for the assessment of plasma IL-6 and TNFα. Cross-sectional associations of childhood trauma and cytokine measures were assessed in both depressed and healthy adolescents, along with exploratory analysis of childhood trauma subtypes. Longitudinal relationships between childhood trauma and cytokine measures were also studied in an exploratory fashion within a subset of depressed participants (n = 36).

RESULTS

Higher childhood trauma (particularly emotional abuse) was positively associated with TNFα in depressed adolescents. Childhood trauma was not linked to longitudinal changes in cytokine levels.

DISCUSSION

In depressed adolescents, childhood trauma may relate to higher levels of the proinflammatory cytokine TNFα and contribute to heterogeneity in cytokine elevation among depressed adolescents. Such findings may ultimately help guide more effective individualized treatments for adolescents with depression.

Molecular Biomarkers for Pediatric Depressive Disorders: A Narrative Review

Depressive disorder in childhood and adolescence is a highly prevalent mood disorder that tends to recur throughout life. Untreated mood disorders can adversely impact a patient’s quality of life and cause socioeconomic loss. Thus, an accurate diagnosis and appropriate treatment is crucial. However, until now, diagnoses and treatments were conducted according to clinical symptoms. Objective and biological validation is lacking. This may result in a poor outcome for patients with depressive disorder. Research has been conducted to identify the biomarkers that are related to depressive disorder. Cumulative evidence has revealed that certain immunologic biomarkers including brain-derived neurotrophic factor (BDNF) and cytokines, gastrointestinal biomarkers, hormones, oxidative stress, and certain hypothalamus-pituitary axis biomarkers are associated with depressive disorder. This article reviews the biomarkers related to the diagnosis and treatment of pediatric depressive disorders. To date, clinical biomarker tests are not yet available for diagnosis or for the prediction of treatment prognosis. However, cytokines such as Interleukin-2, interferon-gamma, tumor necrosis factor-alpha, and BDNF have shown significant results in previous studies of pediatric depressive disorder. These biomarkers have the potential to be used for diagnosis, prognostic assessment, and group screening for those at high risk.

Higher levels of C-reactive protein in the acute phase of stroke indicate an increased risk for post-stroke depression: A systematic review and meta-analysis

BACKGROUND

Investigations have revealed the association between inflammation and post-stroke depression (PSD). However, whether the C-reactive protein (CRP) level, a biomarker of inflammation, would affect the development of PSD is still controversial.

METHODS

A systematic search of databases was performed for eligible studies. Standardized Mean Difference (SMD) with 95 % Confidence Interval (CI) was used to assess the association between the CRP level in the acute phase of stroke and the risk of PSD.

RESULTS

13 cohort studies that involved 3536 participants were included. Combined results showed that compared with non-PSD patients, the CRP level of PSD patients was significantly higher on admission (SMD = 0.19, 95 % CI: 0.12-0.27). A subgroup analysis by classifying the assessment time of depression showed obvious differences of the CRP levels between the PSD patients who were diagnosed more than 1 month after stroke and the non-PSD (1-3 months: SMD = 0.16, 95 % CI: 0.06-0.25; >3months: SMD = 0.34, 95 % CI: 0.18-0.51).

CONCLUSION

A higher level of CRP in the acute phase of stroke suggests an increased risk for PSD.

Immunological Effects of an Add-On Physical Exercise Therapy in Depressed Adolescents and Its Interplay with Depression Severity

BACKGROUND

Pro-inflammatory cytokines (PICs) have gained attention in the pathophysiology and treatment of depressive disorders. At the same time, the therapeutic effect of physical activity seems to work via immunomodulatory pathways. The interventional study "Mood Vibes" analyzed the influence of exercise on depression severity (primary endpoint) in depressive adolescents; the influence of PICs on the clinical outcome was analyzed as a secondary endpoint.

METHODS

Clinically diagnosed depressed adolescents (N = 64; 28.1% male; mean age = 15.9; mean BMI = 24.6) were included and participated either in Whole Body Vibration (WBV) (n = 21) or bicycle ergometer training (n = 20) in addition to treatment-as-usual (TAU). Patients in the control treatment group received TAU only (n = 23). The PICs (interleukin-6-IL-6 and tumor necrosis factor-α-TNF-α) were analyzed before intervention, after 6 weeks of training (t1), and 8 weeks post-intervention (t2). The effects of the treatment on depression severity were rated by self-rating "Depression Inventory for Children and Adolescents" (DIKJ).

RESULTS

Basal IL-6 decreased in all groups from t0 to t1, but it increased again in WBV and controls at t2. TNF-α diminished in ergometer and controls from baseline to t1. PIC levels showed no correlation with depression severity at baseline. The influence on DIKJ scores over time was significant for IL-6 in the WBV group (p = 0.008). Sex had an impact on TNF-α (p < 0.001), with higher concentrations in male patients. Higher body mass index was associated with higher IL-6 concentrations over all measurement points (p < 0.001).

CONCLUSIONS

The positive effects of an intensive add-on exercise therapy on adolescent depression seem to be partly influenced by immunomodulation. A small sample size and non-randomized controls are limitations of this study.

Association of Lymphocyte-to-Monocyte Ratio with Poststroke Depression in Patients with Acute Ischemic Stroke

Background

Poststroke depression (PSD) is a common neuropsychiatric disorder after stroke. The neuroinflammatory response exerts a vital effect in the development of PSD. Lymphocyte-to-monocyte ratio (LMR), a systemic inflammation biomarker, is associated with poor prognosis of acute ischemic stroke (AIS). The purpose of this study was to determine the association between LMR and PSD at 3 months.

Material/Methods

AIS patients (507) were included in this study. Patients were categorized into 3 tertiles and each tertile contains 169 patients: tertile1 (>4.85), tertile 2 (2.96 to 4.85), and tertile 3 (<2.96), based on LMR values and the numbers of patients. PSD was diagnosed with a 17-item Hamilton Depression Scale score of 8 or higher.

Results

Patients (141; 27.8%) were diagnosed with PSD at 3-month follow-up. Patients in the PSD group presented with more severe stroke and lower LMR values (P<0.001). Decreased LMRs were independently associated with occurrence of PSD (middle tertile: odds ratio [OR] 1.823, P=0.037; lowest tertile: OR 3.024, P<0.001). A significant association of a lower LMR value with PSD severity was found (middle tertile: OR 1.883, P=0.031; lowest tertile: OR 2.633, P=0.001). The receiver operating characteristic curve indicates that the optimal threshold of LMR as a predictor for PSD was 3.14, which yielded a sensitivity of 72.4% and a specificity of 68.1%.

Conclusions

Decreased LMR is independently associated with PSD and increased PSD severity.

The relationship between plasma cytokine levels and antidepressant response in patients with first-episode major depressive disorder

BACKGROUND

Cytokines are involved in the pathophysiology of major depressive disorder (MDD) and treatment response. Efforts have been made to identify inflammatory markers but results are often contradictory. The present study explored the plasma levels of multiple cytokines in first-episode MDD using a longitudinal design, with the aim to determine the involvement of cytokines in depression and identify the inflammatory markers.

METHOD

Fifty-four first-episode drug naïve MDD patients and 60 healthy controls (HCs) were enrolled in this study. The 17-item Hamilton Depression Rating Scale (HAMD-17) was administered and blood samples were collected at baseline and four-week posttreatment in MDD group, while blood samples were only collected once in HC group. Plasma levels of nineteen cytokines were examined by a multiplexed flow cytometric assay.

RESULTS

Sixteen out of 19 cytokines levels in MDD group were significantly higher than those in HC group (all P < 0.05). After 4-week of antidepressant treatment, levels of the 14 cytokines elevated at baseline decreased to normal levels (all P < 0.05). Partial correlation showed that baseline level of interferon-inducible T cell alpha chemoattractant (ITAC) was negatively correlated with reduction in HAMD-17 score (r=-0.319, p=0.020), and multiple regression showed lower baseline ITAC level was associated with better treatment response (p = 0.020).

LIMITATION

The sample size was relatively small.

CONCLUSION

A range of cytokines were abnormal in patients with first-episode drug naïve MDD and most of the cytokines could be normalized after antidepressant treatment. Furthermore, baseline ITAC level could be a predictive factor of antidepressant response.

Effects of Antidepressant Treatment on Peripheral Biomarkers in Patients with Major Depressive Disorder (MDD)

Major depressive disorder (MDD) is one of the most prevalent mental illness and a leading cause of disability worldwide. Despite a range of effective treatments, more than 30% of patients do not achieve remission as a result of conventional therapy. In these circumstances the identification of novel drug targets and pathogenic factors becomes essential for selecting more efficacious and personalized treatment. Increasing evidence has implicated the role of inflammation in the pathophysiology of depression, revealing potential new pathways and treatment options. Moreover, convergent evidence indicates that MDD is related to disturbed neurogenesis and suggests a possible role of neurotrophic factors in recovery of function in patients. Although the influence of antidepressants on inflammatory cytokines balance was widely reported in various studies, the exact correlation between drugs used and specific cytokines and neurotrophins serum levels often remains inconsistent. Available data suggest anti-inflammatory properties of selective serotonin reuptake inhibitors (SSRIs), selective serotonin and noradrenaline inhibitors (SNRIs), and tricyclic antidepressants (TCAs) as a possible additional mechanism of reduction of depressive symptoms. In this review, we outline emerging data regarding the influence of different antidepressant drugs on a wide array of peripheral biomarkers such as interleukin (IL)-1ß, IL-2, IL-5, IL-6, IL-8, IL-10, C-reactive protein (CRP), or interferon (IFN)-γ. Presented results indicate anti-inflammatory effect for selected drugs or lack of such effect. Research in this field is insufficient to define the role of inflammatory markers as a predictor of treatment response in MDD.

Personalized Medicine Using Neuroimmunological Biomarkers in Depressive Disorders

Major depressive disorder (MDD) is associated with increased suicidal risk and reduced productivity at work. Neuroimmunology, the study of the immune system and nervous system, provides further insight into the pathogenesis and outcome of MDD. Cytokines are the main modulators of neuroimmunology, and their levels are somewhat entangled in depressive disorders as they affect depressive symptoms and are affected by antidepressant treatment. The use of cytokine-derived medication as a treatment option for MDD is currently a topic of interest. Although not very promising, cytokines are also considered as possible prognostic or diagnostic markers for depression. The machine learning approach is a powerful tool for pattern recognition and has been used in psychiatry for finding useful patterns in data that have translational meaning and can be incorporated in daily clinical practice. This review focuses on the current knowledge of neuroimmunology and depression and the possible use of machine learning to widen our understanding of the topic.

A pro-inflammatory phenotype is associated with behavioural traits in children with Prader-Willi syndrome

Several lines of evidence indicate that immune-inflammatory alterations are widely observed in various mental disorders. Genetic syndromes with high risk of psychiatric disorders may constitute a model for studies investigating this phenomenon. One of such genetically determined neurodevelopmental disorders is the Prader-Willi syndrome (PWS). Therefore, we aimed to profile a broad panel of immune-inflammatory markers in patients with PWS, taking into account co-morbid psychopathology. Participants were 20 children with PWS, and 20 healthy children matched for age, sex and body mass index. Behavioural symptoms and co-occurring psychopathological symptoms were assessed using the Child Behaviour Checklist (CBCL). We found significantly elevated levels of interleukin (IL)-1β and IL-13 in patients with PWS. There were significant positive correlations between the levels of IL-1β and scores of the following externalizing and internalizing CBCL domains: withdrawn/depressed, social problems, thought problems, attention problems, delinquent and aggressive behaviour in PWS children. Moreover, higher levels of IL-13 were associated with more severe psychopathology in terms of social and attention problems as well as delinquent and aggressive behaviour. Our findings imply that subclinical inflammation, observed as elevated IL-1β and IL-13 levels, appears only in PWS patients and is correlated to several psychopathological symptoms.

Longitudinal relationships of cytokines, depression and anhedonia in depressed adolescents

BACKGROUND

Depression has been associated with low-grade elevation of plasma cytokines (e.g. interleukin-6, IL-6; tumor necrosis factor alpha, TNFα) in both cross-sectional and longitudinal studies in adults. Preclinical and clinical studies also suggest that IL-6 and TNFα elevation are associated with anhedonia. However, few studies have examined longitudinal relationships between cytokines and depression/anhedonia in clinically depressed samples, particularly adolescents.

METHODS

Thirty-six adolescents with a depressive disorder receiving standard-of-care community treatment were assessed at a baseline and a follow-up timepoint. Self-report and clinical measures of depression and anhedonia, along with plasma IL-6 and TNFα levels, were obtained at both timepoints. Baseline cytokine measures were examined in association with baseline and follow-up clinical measures. On an exploratory basis, change in clinical measures over time was examined in relation to change in cytokine levels over time.

RESULTS

Higher baseline TNFα levels predicted higher follow-up depression severity after approximately four months (controlling for baseline depression). Higher baseline TNFα levels also associated positively with baseline anhedonia and predicted higher anhedonia at follow-up (controlling for baseline anhedonia). No association was found between change in clinical measures and change in cytokine levels over time.

CONCLUSIONS

Among adolescents receiving standard-of-care community treatment for depression, higher levels of TNFα predicted greater depressive symptoms at 4-month follow-up, suggesting this cytokine may be used to help identify patients in need of more intensive treatment. Elevated TNFα levels were also associated with concurrent and future anhedonia symptoms, suggesting a specific mechanism in which TNFα affects depression trajectories. Future studies should examine the relationships between cytokine levels and depression/anhedonia symptoms at multiple timepoints in larger cohorts of depressed adolescents.

Serum interferon-gamma level is associated with drug-naïve major depressive disorder

Objectives:

Major depressive disorder is a leading heterogeneous psychiatric illness manifested by persistent low mood, a feeling of sadness, and diminished interest in daily activities. Many biological, genetic, and social factors are thought to be linked with depression. But any suitable early risk assessment markers are absent for this illness. Therefore, we aimed to investigate the serum levels of IFN-γ in major depressive disorder patients to further investigate the association between serum levels of this cytokine and major depression.

Methods:

This prospective case-control study enrolled 120 major depressive disorder patients and 100 healthy controls matched by age, sex, and body mass index. A qualified psychiatrist diagnosed the major depressive disorder patients and evaluated healthy controls according to the Diagnostic and Statistical Manual of Mental Health Disorders (5th ed.; DSM-5). The Hamilton depression rating scale was applied for all the study participants to measure the severity of depression. Serum IFN-γ levels were measured by a commercially available enzyme-linked immunosorbent assay kit (Boster Biological Technology, Pleasanton, CA, USA).

Results:

This study observed that serum IFN-γ levels were significantly decreased in major depressive disorder patients compared to healthy controls. A significant negative correlation (r = −0.375; p < 0.001) was obtained between serum IFN-γ levels and Hamilton depression scores. Receiver operating characteristic analysis showed good diagnostic performance of lowered serum IFN-γ levels in depression with an area under the curve at 0.790.

Conclusion:

We suggest the altered serum IFN-γ levels are associated with the pathophysiology of depression. The reduced levels of serum IFN-γ might be used as an early risk assessment tool for major depression.

Depression and inflammation among children and adolescents: A meta-analysis

BACKGROUND

Increasing evidence suggests that youth with Major Depressive Disorder (MDD) exhibit early indicators of cardiovascular disease. A leading hypothesized mechanism of this association is via inflammatory pathways, however, results examining this direct association are mixed. Our objective was to synthesize and quantify observational studies examining the association of depression and inflammation among children and adolescents.

METHODS

Electronic searches were conducted in MEDLINE, Embase, PsycINFO, and Scopus, yielding 2,757 non-duplicate records from 1946 to 2019. The included studies measured depression or depressive symptoms and examined its association with inflammation in participants younger than 18 years. All relevant articles were reviewed and data extracted by two independent coders. Estimates were examined by using random-effects meta-analysis.

RESULTS

Twenty-two studies (20,791 participants) were included. Significant associations were observed between concurrent depression and CRP (n = 7; r = 0.12; 95% confidence interval [CI] = 0.04 to 0.19), and IL-6 (n = 7; r = 0.17; 95% CI= 0.10 to 0.24). Longitudinal analyses revealed that depression is a significant predictor of IL-6 (n = 3; r = 0.29; 95% CI= 0.04 to 0.50) and conversely, that inflammation (measured by CRP or IL-6) predicts future depression (n = 4; r = 0.04; 95% CI= 0.00 to 0.08).

LIMITATIONS

Results are limited by the small number of studies preventing examination of some moderator variables. Findings are correlational, not causal.

CONCLUSION

Depression is positively associated with concurrent and future inflammation among children and adolescents. Results suggest that bidirectional associations may exist between depression and a pro-inflammatory state.

Serum levels of chemokines in adolescents with major depression treated with fluoxetine

BACKGROUND

Major depressive disorder (MDD) is a global health issue that affects 350 million people of all ages. Although between 2% and 5.6% of affected individuals are adolescents, research on young patients is limited. The inflammatory response contributes to the onset of depression, and in adult MDD patients, symptom severity has been linked to chemokine levels.

AIM

To determine the differences in circulatory levels of chemokines in healthy volunteers (HVs) and adolescents with MDD, and assess the changes induced by fluoxetine consume.

METHODS

The 22 adolescents with MDD were monitored during the first 8 wk of clinical follow-up and clinical psychiatric evaluation was done using the Hamilton depresión rating scale (HDRS). The serum levels of monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α, MIP-1β, interleukin (IL)-8, interferon gamma-induced protein (IP)-10, and eotaxin were measured in patients and HVs.

RESULTS

In all cases, significant differences were detected in circulating chemokine levels between patients before treatment and HVs (P < 0.0001). All chemokines decreased at 4 wk, but only MCP-1 and IL-8 significantly differed (P < 0.05) between 0 wk and 4 wk. In the patients, all chemokines rose to their initial concentrations by 8 wk vs 0 wk, but only IP-10 did so significantly (P < 0.05). All patients experienced a significant decrease in HDRS scores at 4 wk (P < 0.0001) and 8 wk (P < 0.0001) compared with 0 wk.

CONCLUSION

Despite the consumption of fluoxetine, patients had significantly higher chemokine levels, even after considering the improvement in HDRS score. The high levels of eotaxin, IP-10, and IL-8 partially explain certain aspects that are affected in MDD such as cognition, memory, and learning.

Prospective study on cytokine levels in medication-naïve adolescents with first-episode major depressive disorder

BACKGROUND

Evidence suggests that depression is correlated with immune-inflammatory responses, and efforts have been made to identify the relationships between depression and inflammatory markers. This study investigated the level of cytokines before and after treatment for major depressive disorder (MDD) in medication-naïve adolescents with first-episode MDD and compared them with the levels in healthy adolescents. The relationship between cytokine levels and the severity of depressive symptoms was also examined.

METHODS

Twenty-five adolescents with MDD and 25 healthy controls aged 13 to 18 years were included in the study. Blood samples were obtained, and depression severity was assessed twice in the MDD group before and after treatment and once in the healthy group.

RESULTS

When compared with healthy controls, adolescents with MDD had lower levels of interleukin 2 (IL-2), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α) and IL-10 before treatment and higher levels of IL-2, IFN-γ, and IL-10 after treatment. In addition, the IFN-γ levels correlated with depressive severity scores in both the Children's Depression Inventory (CDI) and Hamilton Depression Rating Scale (HDRS). The IL-10 level correlated with depressive severity only on the HDRS.

LIMITATIONS

The sample size was small, and the 12-week follow-up time after treatment was relatively short.

CONCLUSION

IL-2, IFN-γ, TNF-α, and IL-10 levels in medication-naïve adolescents with first-episode MDD differed from those in healthy controls. The levels of IL-2, IFN-γ, and IL-10 were altered after antidepressant treatment. Further, the IFN-γ and IL-10 levels correlated with the severity of depressive symptoms.

Novel Insight into Neuroimmune Regulatory Mechanisms and Biomarkers Linking Major Depression and Vascular Diseases: The Dilemma Continues

Major depressive disorder (MDD) represents a serious health problem estimated to affect 350 million people globally. Importantly, MDD has repeatedly emerged as an etiological or prognostic factor in cardiovascular disease (CVD) development, including vascular pathology. Several linking pathomechanisms between MDD and CVD involve abnormal autonomic regulation, inflammation, and endothelial dysfunction as an early preclinical stage of atherosclerosis. However, the cause of accelerated atherosclerosis in MDD patients remains unclear. Recently, the causal relationships between MDD and mediator (e.g., inflammation and/or endothelial dysfunction), as well as the causal pathways from the mediator to atherosclerosis, were discussed. Specifically, MDD is accompanied by immune dysregulation, resulting in increased production of proinflammatory cytokines (e.g., interleukin (IL)-6 and tumor necrosis factor (TNF)-α), which could lead to depression-linked abnormalities in brain function. Further, MDD has an adverse effect on endothelial function; for example, circulating markers of endothelial dysfunction (e.g., soluble adhesion molecules, von Willebrand factor) have been linked with depression. Additionally, MDD-linked autonomic dysregulation, which is characterized by disrupted sympathovagal balance associated with excessive circulating catecholamines, can contribute to CVD. Taken together, activated inflammatory response, endothelial dysfunction, and autonomic dysregulation could affect gradual atherosclerosis progression, resulting in a higher risk of developing CVD in MDD. This review focused on the pathomechanisms linking MDD and CVD with respect to neuroimmune regulation, and the description of promising biomarkers, which is important for the early diagnosis and personalized prevention of CVD in major depression.

Bibliometric and Visual Analysis of Research on the Links Between the Gut Microbiota and Depression From 1999 to 2019

Background: There is a crucial link between the gut microbiota and the host central nervous system, and the communication between them occurs via a bidirectional pathway termed the "microbiota-gut-brain axis." The gut microbiome in the modern environment has markedly changed in response to environmental factors. These changes may affect a broad range of host psychiatric disorders, such as depression, by interacting with the host through metabolic, immune, neural, and endocrine pathways. Nevertheless, the general aspects of the links between the gut microbiota and depression have not been systematically investigated through bibliometric analysis. Aim: This study aimed to analyze the current status and developing trends in gut microbiota research in the depression field through bibliometric and visual analysis. Methods: A total of 1,962 publications published between 1999 and 2019 were retrieved from the Web of Science Core Collection. CiteSpace (5.6 R5) was used to perform collaboration network analysis, co-citation analysis, co-occurrence analysis, and citation burst detection. Results: The number of publications has been rapidly growing since 2010. The collaboration network analysis revealed that the USA, University College Cork, and John F. Cryan were the most influential country, institute, and scholar, respectively. The most productive and co-cited journals were Brain Behavior and Immunity and Proceedings of the National Academy of Sciences of the United States of America, respectively. The co-citation analysis of references revealed that the most recent research focus was in the largest theme cluster, "cytokines," thus reflecting the important research foundation in this field. The co-occurrence analysis of keywords revealed that "fecal microbiota" and "microbiome" have become the top two research hotspots since 2013. The citation burst detection for keywords identified several keywords, including "Parkinson's disease," "microbiota-gut-brain axis," "microbiome," "dysbiosis," "bipolar disorder," "impact," "C reactive protein," and "immune system," as new research frontiers, which have currently ongoing bursts. Conclusions: These results provide an instructive perspective on the current research and future directions in the study of the links between the gut microbiota and depression, which may help researchers choose suitable cooperators or journals, and promote their research illustrating the underlying molecular mechanisms of depression, including its etiology, prevention, and treatment.

Alterations in the Levels of Growth Factors in Adolescents with Major Depressive Disorder: A Longitudinal Study during the Treatment with Fluoxetine

Major depressive disorder (MDD) has a prevalence of 5% in adolescents. Several studies have described the association between the inflammatory response and MDD, but little is known about the relationship between MDD and growth factors, such as IL-7, IL-9, IL-17A, VEGF, basic FGF, G-CSF, and GM-CSF. It must be appointed that there are scarce reports on growth factors in adolescents with MDD and even fewer with a clinical follow-up. In this work, we evaluated the levels of growth factors (IL-7, IL-9, IL-17A, VEGF, basic FGF, G-CSF, and GM-CSF) in MDD adolescents and the clinical follow-up during eight weeks of treatment with fluoxetine. Methods. All patients were diagnosed according to the DSM-IV-TR, and the severity of the symptoms was evaluated using the Hamilton Depression Rating Scale (HDRS). Growth factors IL-7, IL-9, IL-17A, VEGF, basic FGF, G-CSF, and GM-CSF were quantified by cytometric bead array using serum samples from 22 adolescents with MDD and 18 healthy volunteers. Results. All patients showed clinical improvement since the fourth week of pharmacological treatment according to the HDRS. Considerably higher levels of IL-7, IL-9, IL-17A, VEGF, basic FGF, G-CSF, and GM-CSF were detected in MDD adolescents as compared to healthy volunteers. A significant but temporal decrease was detected in basic FGF, G-CSF, and GM-CSF at week four of fluoxetine administration. Conclusions. To the best of our knowledge, this is the first report to show alterations in the levels of growth factors, such as IL-7, IL-9, IL-17A, VEGF, basic FGF, G-CSF, and GM-CSF in MDD adolescents during eight weeks of clinical follow-up. These disturbances might be involved in the physiopathology of MDD since such growth factors have been proven to participate in the neural development and correct functioning of the CNS; therefore, subtle alterations in it may contribute to MDD.

Trained Innate Immunity Not Always Amicable

The concept of &bdquo;trained innate immunity" is understood as the ability of innate immune cells to remember invading agents and to respond nonspecifically to reinfection with increased strength. Trained immunity is orchestrated by epigenetic modifications leading to changes in gene expression and cell physiology. Although this phenomenon was originally seen mainly as a beneficial effect, since it confers broad immunological protection, enhanced immune response of reprogrammed innate immune cells might result in the development or persistence of chronic metabolic, autoimmune or neuroinfalmmatory disorders. This paper overviews several examples where the induction of trained immunity may be essential in the development of diseases characterized by flawed innate immune response.