Oxidative Stress in Depression: The Link with the Stress Response, Neuroinflammation, Serotonin, Neurogenesis and Synaptic Plasticity

From blood to brain: Exploring the role of fibrinogen in the pathophysiology of depression and other neurological disorders

Recent findings indicate that fibrinogen, a protein involved in blood clotting, plays a significant role in neuroinflammation and mood disorders. Elevated fibrinogen levels are consistently observed in individuals with depression, potentially contributing to microglial activation. This could impair fibrinolysis and contribute to a pro-inflammatory environment in the brain. This neuroinflammatory response can impair neuroplasticity, a key process for learning, memory, and mood regulation. Fibrinogen may also indirectly influence neurotransmitters like serotonin, which play a vital role in mood regulation. Furthermore, fibrinogen's interaction with astrocytes may trigger a cascade of events leading to demyelination, a process where the protective sheath around nerve fibers deteriorates. This can disrupt communication within the nervous system and contribute to depression symptoms. Intriguingly, targeting fibrinogen or related pathways holds promise for therapeutic interventions. For instance, modulating PAI-1 (Plasminogen activator inhibitor-1) activity or inhibiting fibrinogen's interaction with brain cells could be potential strategies. This review explores the multifaceted relationship between fibrinogen and neurological disorders with a focus on depression highlighting its potential as a therapeutic target. Further research is necessary to fully elucidate the mechanisms underlying this association and develop effective therapeutic strategies targeting the fibrinolytic system for mood disorders.

Association of Neutrophil-Percentage-To-Albumin Ratio(NPAR) with depression symptoms in U.S. adults: a NHANES study from 2011 to 2018

BACKGROUND

Inflammation is crucial in the development of depression. This study aims to examine the potential association between the Neutrophil-Percentage-to-Albumin Ratio(NPAR) and depression symptoms.

METHODS

This study adopted a cross-sectional design, involving patients with depression symptoms and those without depression symptoms with comprehensive NPAR data originated from the National Health and Nutrition Examination Survey(NHANES) spanning 2011 to 2018. The research utilized weighted multivariate logistic regression models and multivariate linear regression to investigate the linear relationship between NPAR levels and depression symptoms and its severity scores. The characterization of nonlinear relationships was accomplished by employing fitted smoothing curves. Furthermore, subgroup analyses and interaction assessments were conducted to offer additional insights.

RESULTS

This study involved a total of 10,829 participants, and the prevalence of depression among them was found to be 15.08%. The multiple logistic regression analysis revealed a statistically significant positive association between the continuum of NPAR and depression symptoms[OR:1.03, 95% CI: (1.00, 1.05)], as well as depression severity scores[β: 0.08, 95% CI: (0.04,0.11)]. Stratifying NPAR into quartiles, we found that higher NPAR associated with increased odds of depression symptoms. Furthermore, in subgroup analysis, there were no significant differences in the relationship between NPAR levels and depression symptoms or its severity scores within populations with or without diabetes and cardiovascular diseases. Additionally, the use of a two-stage linear regression model uncovered a non-linear relationship between NPAR and depression symptoms.

CONCLUSIONS

Our research indicates that NPAR levels were associated with depression symptoms. To corroborate our findings, larger prospective studies are warranted to elucidate nonlinear associations in greater detail.

Combined Restraint Stress and Metal Exposure Paradigms in Rats: Unravelling Behavioural and Neurochemical Perturbations

Accumulation of heavy metals (Mn and Ni) and prolonged exposure to stress are associated with adverse health outcomes. Various studies have shown the impacts of stress and metal exposures on brain function. However, no study has examined the effects of co-exposure to stress, Mn, and Ni on the brain. This study addresses this gap by evaluating oxidative and glial responses, apoptotic activity, as well as cognitive processes in a rat model. Adult Wistar rats were exposed to vehicle (control), restraint stress, 25 mg/kg of manganese (Mn) or nickel (Ni), or combined restraint stress plus Mn or Ni. Following treatment, rats were subjected to several behavioural paradigms to assess cognitive function. Enzyme activity, as well as ATPase levels, were evaluated. Thereafter, an immunohistochemical procedure was utilised to evaluate neurochemical markers of glial function, myelination, oxidative stress, and apoptosis in the hippocampus, prefrontal cortex (PFC), and striatum. Results showed that stress and metal exposure increased oxidative stress markers and reduced antioxidant levels. Further, combined stress and metal exposure reduced various forms of learning and memory ability in rats. In addition, there were alterations in Iba1 activity and Nrf2 levels, reduced Olig2 and myelin basic protein (MBP) levels, and increased caspase-3 expression. These neurotoxic outcomes were mostly exacerbated by co-exposure to stress and metals. Overall, our findings establish that stress and metal exposures impaired cognitive performance, induced oxidative stress and apoptosis, and led to demyelination effects which were worsened by combined stress and metal exposure.

The Potential Role of Polyphenol Supplementation in Preventing and Managing Depression: A Review of Current Research

Depression is a common mental illness that affects 5% of the adult population globally. The most common symptoms of depression are low mood, lack of pleasure from different activities, poor concentration, and reduced energy levels for an extended period, and it affects the emotions, behaviors, and overall well-being of an individual. The complex pathophysiology of depression presents challenges for current therapeutic options involving a biopsychosocial treatment plan. These treatments may have a delayed onset, low remission and response rates, and undesirable side effects. Researchers in nutrition and food science are increasingly addressing depression, which is a significant public health concern due to the association of depression with the increased incidence of cardiovascular diseases and premature mortality. Polyphenols present in our diet may significantly impact the prevention and treatment of depression. The primary mechanisms include reducing inflammation and oxidative stress, regulating monoamine neurotransmitter levels, and modulating the microbiota-gut-brain axis and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. This review summarizes recent advances in understanding the effects of dietary polyphenols on depression and explores the underlying mechanisms of these effects for the benefit of human health. It also highlights studies that are looking at clinical trials to help future researchers incorporate these substances into functional diets, nutritional supplements, or adjunctive therapy to prevent and treat depression.

Particulate Matter-Induced Emerging Health Effects Associated with Oxidative Stress and Inflammation

Environmental pollution continues to increase with industrial development and has become a threat to human health. Atmospheric particulate matter (PM) was designated as a Group 1 carcinogen by the International Agency for Research on Cancer in 2013 and is an emerging global environmental risk factor that is a major cause of death related to cardiovascular and respiratory diseases. PM is a complex composed of highly reactive organic matter, chemicals, and metal components, which mainly cause excessive production of reactive oxygen species (ROS) that can lead to DNA and cell damage, endoplasmic reticulum stress, inflammatory responses, atherosclerosis, and airway remodeling, contributing to an increased susceptibility to and the exacerbation of various diseases and infections. PM has various effects on human health depending on the particle size, physical and chemical characteristics, source, and exposure period. PM smaller than 5 μm can penetrate and accumulate in the alveoli and circulatory system, causing harmful effects on the respiratory system, cardiovascular system, skin, and brain. In this review, we describe the relationship and mechanism of ROS-mediated cell damage, oxidative stress, and inflammatory responses caused by PM and the health effects on major organs, as well as comprehensively discuss the harmfulness of PM.

Brain-derived neurotrophic factor modulation in response to oxidative stress and corticosterone: role of scopolamine and mirtazapine

Major Depressive Disorder (MDD) is a very complex disease, challenging to study and manage. The complexities of MDD require extensive research of its mechanisms to develop more effective therapeutic approaches. Crucial in the context of this disease is the role of brain-derived neurotrophic factor (BDNF) signaling pathway.

AIM

This manuscript aims to explore the complex relationship between MDD and BDNF signaling pathway, focusing on how BDNF is modulated in response to oxidative stress and corticosterone, known to be altered in MDD and contributing to the pathology of the disorder, when treated with scopolamine and mirtazapine.

METHODS

To assess BDNF levels after the different treatment conditions, rat hippocampal slices and mice primary hippocampus and cortical cell culture were analyzed by immunofluorescence and Western blot.

KEY FINDINGS

Both mirtazapine and scopolamine under stress conditions induced by hydrogen peroxide (H2O2) and corticosterone, had a significant impact on BDNF levels, and this was distinct in different neuronal models. Mirtazapine, especially when combined with H2O2, altered BDNF expression. Scopolamine when combined with both stressors also altered BDNF levels. However, its effects varied depending on the specific neuronal model and stress condition. In accordance with BDNF results, phosphorylated tropomyosin receptor kinase B (pTrkB) presented increased activation when neuronal cells subjected to stress were treated with mirtazapine or scopolamine.

SIGNIFICANCE

Collectively, this study highlights the complex connection between these compounds, stress conditions, and BDNF/TrkB modulation, supporting the potential therapeutic effects of scopolamine and mirtazapine in modulating BDNF levels, even in stressful conditions.

Higher atherogenic index of plasma is associated with increased major depressive disorder: insights from a nationally representative study

Background

Emerging studies reveal a shared pathophysiological underpinning for metabolic problems and mental illnesses. The present study aimed to determine the association between atherogenic index of plasma (AIP) and the incidence of major depressive disorder (MDD).

Methods

7,951 subjects of US adults were collected from the National Health and Nutrition Examination Survey (NHANES) 2005-2018. MDD was evaluated through the Patient Health Questionnaire (PHQ-9). Multivariate logistic regression, sensitivity analysis, and spline smoothing plot method were used to identify the relationship between AIP and MDD. The cut-off point was calculated using recursive partitioning analysis when segmenting effects emerged. The area under the receiver operating characteristic (ROC) curve (AUC) and Hosmer-Lemeshow test were conducted to evaluate the performance of AIP in identifying MDD. Subgroup analyses and interaction tests were used to explore whether the association was stable in different populations.

Results

A positive correlation between AIP and PHQ-9 score and MDD was both observed in 7,951 subjects included in the study, with a significant threshold of -0.42 determined using recursive partitioning analysis. In the fully adjusted model, a positive association between AIP and PHQ-9 score and MDD was observed (β=0.46, 95% CI 0.14~0.78; OR=1.42, 95% CI 1.04~1.93). Individuals in the highest AIP quartile had a 0.39-unit higher PHQ-9 score (β=0.39, 95% CI 0.12~0.66) and a significantly 33% greater risk of MDD than those in the lowest AIP quartile (OR=1.33, 95% CI 1.02~1.73). Spline smoothing plot analysis further confirmed the positive and non-linear association between AIP and PHQ-9 and MDD. ROC analysis (AUC=0.771) and the Hosmer-Lemeshow test (χ2 = 14.239, P=0.076) suggested an excellent performance and goodness-of-fit of the relatively optimal model. DCA and CIC analysis also revealed a favorable overall net benefit and clinical impact of the model. Subgroup analyses and interaction tests revealed that the association between AIP and PHQ-9 score and MDD remained consistent across different subgroups and was not modified by other covariates, and this positive correlation was more pronounced in those with diabetes or hypertension.

Conclusion

An elevated AIP is linked to a higher chance of MDD, especially in those with diabetes or hypertension. Resolving dyslipidemia and managing comorbidities may help reduce the likelihood of developing MDD.

Inflammation environment-adaptive matrix confinement for three-dimensional modulation of macrophages

The balance of macrophages in immune reactions is crucial for tissue repair. Despite some studies on responsive surfaces for immunomodulation regulation of macrophage phenotypes via external stimuli, 2D and manual interventions are limited. Herein, to address these limitations, we developed an inflammation environment-responsive macrophage-laden hydrogel-filled scaffold for investigating the impact of matrix confinement on macrophage phenotypes adaptively. We fabricated gelatin scaffolds with a controllable pore size and found that macrophages within smaller pores tended to have an anti-inflammation phenotype. We prepared poly(vinyl alcohol) (PVA)-based hydrogels crosslinked with phenylboronic acid (PBA)-based linkers. The hydrogels possessed shear-thinning, cell-loading, and ROS-sensitive-degradation abilities. Subsequently, a macrophage-laden hydrogel-filled scaffold was fabricated by filling the hydrogels into the porous scaffold under vacuum. With the degradation of the hydrogels under the overexpression of ROS in an inflammation environment, the macrophages were transferred from a state with strong matrix confinement to that with a weaker one. Meanwhile, with the change in matrix confinement, the macrophages upregulated the expressions of Arg-1 and IL-10 and downregulated the expressions of IL-1β, TNF-α, and IL-6, indicating polarization toward the anti-inflammatory phenotype. The inflammation environment-adaptive modulation of macrophage phenotypes in 3D provides a smart and biomimetic strategy for immunomodulation and regenerative medicine.

Ethylene oxide exposure, inflammatory indicators, and depressive symptoms: a cross-sectional study and mediation analysis based on a non-institutionalized American population

Background

Ethylene oxide (EO) is a volatile compound positively correlated with respiratory and cardiovascular diseases. Currently, evidence suggests that environmental exposure may contribute to depressive symptoms. This study evaluated the correlation between EO exposure and depressive symptoms and investigated whether inflammatory indicators had a mediation effect on this correlation.

Methods

Patients were enrolled from the National Health and Nutrition Examination Survey during 2013-2016, and 2,764 (49.67% male and 50.33% female) participants were ultimately included. EO exposure was determined by measuring hemoglobin-EO adduct (Hb-EO) concentration due to its long half-life, which was log2-transformed. Depressive symptoms were assessed using the Patient Health Questionnaire-9. Multivariable logistic regression analysis was performed to identify any correlations before and after covariate adjustment. Sensitivity analysis, subgroup analyses, and interaction tests were performed to further evaluate identified correlations. Mediation analysis was conducted to reveal whether specific inflammatory indicators mediated the correlation.

Results

A high prevalence of depressive symptoms was observed in quartiles with increased levels of EO exposure, and male individuals exhibiting higher Hb-EO levels than female individuals. A positive correlation was observed between EO exposure and depressive symptoms (odds ratio [OR]: 1.439, 95% confidence interval [CI]: 1.310, 1.581), which remained stable even after covariate adjustment (OR: 1.332, 95% CI: 1.148, 1.545). Interaction tests showed significant effects of sex (p < 0.001) and thyroid diseases (p = 0.048) on this correlation. In the mediation analysis, white blood cell (p = 0.010) and neutrophil counts (p = 0.010) exerted a mediating effect, accounting for 13.6 and 11.9%, respectively.

Conclusion

Increased exposure to EO is associated with an elevated risk of depressive symptoms, where white blood cell and neutrophil counts exert a significant mediating effect. Further prospective studies are required to investigate the potential link among EO, other environmental pollutants, and human mental health.

Risk of depression in amyotrophic lateral sclerosis: A nationwide cohort study in South Korea

Depression is frequently reported in amyotrophic lateral sclerosis (ALS) due to the disastrous prognosis of progressive motor impairment, but the risk of depression in ALS is still unclear. Therefore, we investigated the risk of depression in ALS and analyzed the effect of ALS-related physical disability on the risk of developing depression using the Korean National Health Insurance Service (KNHIS) database. A total of 2241 ALS patients, as defined by the International Classification Diseases (ICD, G12.21) and Rare Intractable Disease codes (V123), and 1:10 sex- and age-matched controls were selected from the KNHIS. After applying exclusion criteria (non-participation in national health screening, history of depression, or having missing data), 595 ALS patients and 9896 non-ALS individuals were finally selected. Primary outcome is newly diagnosed depression during follow-up duration defined by ICD code (F32 or F33). A Cox regression model was used to examine the hazard ratios (HRs) after adjustment for potential confounders. During the follow-up period, 283 cases of depression in the ALS group and 1547 in the controls were recorded. The adjusted HR for depression in ALS was 9.1 (95% confidence interval [CI] 7.87-10.60). The risk of depression was slightly higher in the disabled ALS group (aHR 10.1, 95% CI 7.98-12.67) than in the non-disabled ALS group (aHR 8.78, 95% CI 7.42-10.39). The relative risk of depression was higher in younger patients than in older patients, and in obese patients than in non-obese patients. Our study showed that ALS patients have an increased risk of depression compared to non-ALS individuals.

Nasal administration of mitochondria relieves depressive- and anxiety-like behaviors in male mice exposed to restraint stress through the suppression ROS/NLRP3/caspase-1/IL-1β signaling pathway

Neuroinflammation and oxidative stress are known to be implicated in the pathogenesis of depression. Exogenous mitochondrial transplantation has exhibited beneficial effects for treating neurological disorders. Hence, this research aimed to evaluate the impact of nasal administration of mitochondria on neuroinflammation and oxidative stress in mouse models displaying depressive- and anxiety-like behaviors caused by restraint stress (RS). Thirty male BALB/c mice were divided into control, RS, and RS + 340 µg of mitochondrial. Mice were subjected to RS using an immobilization falcon tube (2 h/day) for 2 weeks except for the control group. We conducted two behavioral tests to evaluate anxiety-like behaviors: elevated plus maze (EPM) and open field test (OFT). Tail suspension test (TST) was implemented to assess depressive-like behavior. ATP and reactive oxygen species (ROS) levels were measured in the hippocampus. Besides, serum corticosterone (CORT) levels were evaluated using the ELISA method. The expression of NLRP3 inflammasome, caspase-1 (Cas-1), and IL-1β was tested by western blot. We found that mitotherapy increased the time spent in the center of OFT and open arms of the EPM, while it diminished immobility time in TST. Mitochondrial administration considerably attenuated ROS generation and CORT levels and restored ATP levels. Additionally, mitotherapy prevented RS-induced upregulation of IL-1β, cleaved Cas1/Pro Cas1 ratio, and NLRP3/1 in the hippocampus of mice. These findings suggested that the beneficial effects of intranasal mitochondria on depression and anxiety may be attributed to suppression of the ROS/NLRP3/IL-1β/caspase-1 signaling pathway.

Targeting Toll-like Receptor 4/Nuclear Factor-κB and Nrf2/Heme Oxygenase-1 Crosstalk via Trimetazidine Alleviates Lipopolysaccharide-Induced Depressive-like Behaviors in Mice

Depression is a global psychiatric illness that imposes a substantial economic burden. Unfortunately, traditional antidepressants induce many side effects which limit patient compliance thus, exploring alternative therapies with fewer adverse effects became urgent. This study aimed to investigate the effect of trimetazidine (TMZ); a well-known anti-ischemic drug in lipopolysaccharide (LPS) mouse model of depression focusing on its ability to regulate toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) as well as nuclear factor erythroid 2 related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) signaling pathways. Male Swiss albino mice were injected with LPS (500 µg/kg, i.p) every other day alone or parallel with oral doses of either escitalopram (Esc) (10 mg/kg/day) or TMZ (20 mg/kg/day) for 14 days. Treatment with TMZ attenuated LPS-induced animals' despair with reduced immobility time inforced swimming test. TMZ also diminished LPS- induced neuro-inflammation via inhibition of TLR4/NF-κB pathway contrary to Nrf2/HO-1 cascade activation with consequent increase in reduced glutathione (GSH) and HO-1 levels whereas the pro-inflammatory cytokines; tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β were evidently reduced. Besides, TMZ replenished brain serotonin levels via serotonin transporter (SERT) inhibition. Thus, TMZ hindered LPS-induced neuro-inflammation, oxidative stress, serotonin deficiency besides its anti-apoptotic effect which was reflected by decreased caspase-3 level. Neuroprotective effects of TMZ were confirmed by the histological photomicrographs which showed prominent neuronal survival. Here we showed that TMZ is an affluent nominee for depression management via targeting TLR4/NF-κB and Nrf2/HO-1 pathways. Future research addressing TMZ-antidepressant activity in humans is mandatory to enroll it as a novel therapeutic strategy for depression.

Umbelliprenin attenuates comorbid behavioral disorders in acetic acid-induced colitis in mice: mechanistic insights into hippocampal oxidative stress and neuroinflammation

Inflammatory bowel disease (IBD) is often accompanied by psychiatric disorders. Emerging evidence suggests that neuroinflammation and oxidative stress contribute to the psychiatric symptoms associated with IBD. Umbelliprenin (UMB) possesses several pharmacological properties, including anti-inflammatory and antioxidant effects. This study aimed to investigate the protective effects of UMB on comorbid behavioral disorders in a mouse model of experimental colitis, focusing on its potential anti-neuroinflammatory and antioxidant activities. After inducing colitis with acetic acid, male NMRI mice were treated for 7 consecutive days with UMB, saline, or dexamethasone. Behavioral assessments included the forced swimming test (FST), splash test, open field test (OFT), and elevated plus maze (EPM). Histopathological changes in the colon were evaluated, and total antioxidant capacity (TAC), malondialdehyde (MDA) levels, and the expression of inflammatory genes (TNFα, IL1β, and TLR4) were measured in the hippocampus. Colitis was associated with increased immobility time in the FST, reduced entries and time spent in the open arms of the EPM, decreased grooming behavior in the splash test, and reduced time spent in the central zone of the OFT. Colitis also resulted in a reduction in TAC and an increase in MDA levels and inflammatory gene expression in the hippocampus. UMB treatment mitigated the behavioral disorders associated with colitis, reduced neuroinflammation and oxidative stress in the hippocampus, and alleviated histopathological alterations in the colon. In conclusion, UMB may reduce behavioral disorders induced by colitis by decreasing oxidative stress and neuroinflammation in the hippocampus.

Cardiac biogenic amine profile and its relationship with parameters of cardiovascular disease in obesity

AIMS

To identify the cardiac biogenic amine profile of obese rats and associate these compounds with parameters of cardiovascular disease.

MAIN METHODS

Wistar rats (n = 20) were randomly distributed into two groups: control and obese. Obesity was induced by a high-sugar fat diet. Biochemical parameters were evaluated. Doppler Echocardiography and systolic blood pressure; interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α), protein carbonylation, ferric reducing antioxidant power (FRAP), and catalase activity were measured in cardiac tissue. HPLC evaluated the cardiac biogenic profile. Data were compared using the Student's T or Mann-Whitney tests and Spearman's correlation at 5% significance. The principal component analysis (PCA) was performed.

KEY FINDINGS

Obesity generated hypertension, cardiac remodeling and dysfunction, and imbalanced all biochemical, inflammatory, and oxidative markers (p < 0.001). Eight biogenic amines were found in cardiac tissue. Obesity increased serotonin and decreased agmatine, putrescine, cadaverine, and spermidine. Serotonin (r = 0.534 to 0.808) was strong and positively correlated with obesity, biochemical parameters, cardiac inflammation, oxidative stress, hypertension, cardiac remodeling, and dysfunction (p < 0.001). Spermidine (r = -0.560 to -0.680), putrescine (r = -0.532 to -0.805), cadaverine (r = -0.534 to -0.860), and agmatine (r = -0.579 to -0.884) were inversely correlated with the same parameters (p < 0.001). PCA allowed for distinguishing the control and obese groups.

SIGNIFICANCE

There are strong correlations between cardiac biogenic amine levels, cardiac remodeling, and dysfunction resulting from obesity.

CONCLUSION

There is an association between cardiac biogenic amines and cardiovascular disease in obesity. In addition, agmatine, putrescine, cadaverine, and, mainly, serotonin may be new biomarkers for cardiovascular health in obesity and help to improve the diagnosis and treatment of CVD resulting or not from obesity. However, more research is needed to support this conclusion.

Increased malondialdehyde and nitric oxide formation, lowered total radical trapping capacity coupled with psychological stressors are strongly associated with the phenome of first-episode mild depression in undergraduate students

Undergraduate students are frequently afflicted by major depressive disorder (MDD). Oxidative and nitrosative stress (O&NS) has been implicated in the pathophysiology of MDD. There is no information regarding whether mild outpatient MDD (SDMD) and first episode SDMD (FE-SDMD) are accompanied by O&NS. The current study compared lipid hydroperoxides (LOOH), malondialdehyde (MDA), advanced protein oxidation products, nitric oxide metabolites (NOx), thiol groups, plasma total antioxidant potential (TRAP), and paraoxonase 1 activities among SDMD and FE-SDMD patients versus healthy controls. We found that SDMD and FE-SDMD exhibit elevated MDA and NOx, and decreased TRAP and LOOH as compared with controls. There was a significant and positive correlation between O&NS biomarkers and adverse childhood experiences (ACEs), and negative life events (NLEs). O&NS pathways, NLEs and ACEs accounted for 51.7 % of the variance in the phenome of depression, and O&NS and NLS explained 42.9 % of the variance in brooding. Overall, these results indicate that SDMD and FE-SDMD are characterized by reduced total antioxidant defenses and increased aldehyde and NOx production. The combined effects of oxidative and psychological stressors are substantially associated with the manifestation of SDMD.

Empagliflozin-activated AMPK elicits neuroprotective properties in reserpine-induced depression via regulating dynamics of hippocampal autophagy/inflammation and PKCζ-mediated neurogenesis

RATIONALE

Major depression has been an area of extensive research during the last decades, for it represents a leading cause of disability and suicide. The stark rise of depression rates influenced by life stressors, economic threats, pandemic era, and resistance to classical treatments, has made the disorder rather challenging. Adult hippocampal neurogenesis and plasticity are particularly sensitive to the dynamic interplay between autophagy and inflammation. In fact, the intricate balance between the two processes contributes to neuronal homeostasis and survival.

OBJECTIVES

Having demonstrated promising potentials in AMPK activation, a major metabolic sensor and autophagy regulator, empagliflozin (Empa) was investigated for possible antidepressant properties in the reserpine rat model of depression.

RESULTS

While the reserpine protocol elicited behavioral, biochemical, and histopathological changes relevant to depression, Empa outstandingly hindered these pathological perturbations. Importantly, hippocampal autophagic response markedly declined with reserpine which disrupted the AMPK/mTOR/Beclin1/LC3B machinery and, conversely, neuro-inflammation prevailed under the influence of the NLRP3 inflammasome together with oxidative/nitrative stress. Consequently, AMPK-mediated neurotrophins secretion obviously deteriorated through PKCζ/NF-κB/BDNF/CREB signal restriction. Empa restored hippocampal monoamines and autophagy/inflammation balance, driven by AMPK activation. By promoting the atypical PKCζ phosphorylation (Thr403) which subsequently phosphorylates NF-κB at Ser311, AMPK successfully reinforced BDNF/CREB signal and hippocampal neuroplasticity. The latter finding was supported by hippocampal CA3 toluidine blue staining to reveal intact neurons.

CONCLUSION

The current study highlights an interesting role for Empa as a regulator of autophagic and inflammatory responses in the pathology of depression. The study also pinpoints an unusual contribution for NF-κB in neurotrophins secretion via AMPK/PKCζ/NF-κB/BDNF/CREB signal transduction. Accordingly, Empa can have special benefits in diabetic patients with depressive symptoms.

LIMITATIONS

The influence of p-NF-κB (Ser311) on NLRP3 inflammasome assembly and activation has not been investigated, which can represent an interesting point for further research.

Omega-3 Polyunsaturated Fatty Acids in Depression

Omega-3 polyunsaturated fatty acids have received considerable attention in the field of mental health, in particular regarding the treatment of depression. This review presents an overview of current research on the role of omega-3 fatty acids in the prevention and treatment of depressive disorders. The existing body of evidence demonstrates that omega-3 fatty acids, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have antidepressant effects that can be attributed to their modulation of neuroinflammation, neurotransmitter function, and neuroplasticity. Nevertheless, clinical trials of omega-3 supplementation have yielded inconsistent results. Some studies have demonstrated significant reductions in depressive symptoms following omega-3 treatment, whereas others have shown minimal to no beneficial impact. A range of factors, encompassing dosage, the ratio of EPA to DHA, and baseline nutritional status, have been identified as having a potential impact on the noted results. Furthermore, it has been suggested that omega-3 fatty acids may act as an adjunctive treatment for those undergoing antidepressant treatment. Notwithstanding these encouraging findings, discrepancies in study designs and variability in individual responses underscore the necessity of further research in order to establish uniform, standardized guidelines for the use of omega-3 fatty acids in the management of depressive disorders.

Identification of oxidative stress-related diagnostic markers and immune infiltration features for idiopathic pulmonary fibrosis by bibliometrics and bioinformatics

Idiopathic pulmonary fibrosis (IPF) garners considerable attention due to its high fatality rate and profound impact on quality of life. Our study conducts a comprehensive literature review on IPF using bibliometric analysis to explore existing hot research topics, and identifies novel diagnostic and therapeutic targets for IPF using bioinformatics analysis. Publications related to IPF from 2013 to 2023 were searched on the Web of Science Core Collection (WoSCC) database. Data analysis and visualization were conducted using CiteSpace and VOSviewer software primarily. The gene expression profiles GSE24206 and GSE53845 were employed as the training dataset. The GSE110147 dataset was employed as the validation dataset. We identified differentially expressed genes (DEGs) and differentially expressed genes related to oxidative stress (DEOSGs) between IPF and normal samples. Then, we conducted Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The hub genes were screened by protein-protein interaction (PPI) networks and machine learning algorithms. The CIBERSORT was used to analyze the immune infiltration of 22 kinds of immune cells. Finally, we conducted the expression and validation of hub genes. The diagnostic efficacy of hub genes was evaluated by employing Receiver Operating Characteristic (ROC) curves and the associations between hub genes and immune cells were analyzed. A total of 6,500 articles were identified, and the annual number of articles exhibited an upward trend. The United States emerged as the leading contributor in terms of publication count, institutional affiliations, highly cited articles, and prolific authorship. According to co-occurrence analysis, oxidative stress and inflammation are hot topics in IPF research. A total of 1,140 DEGs were identified, and 72 genes were classified as DEOSGs. By employing PPI network analysis and machine learning algorithms, PON2 and TLR4 were identified as hub genes. A total of 10 immune cells exhibited significant differences between IPF and normal samples. PON2 and TLR4, as oxidative stress-related genes, not only exhibit high diagnostic efficacy but also show close associations with immune cells. In summary, our study highlights oxidative stress and inflammation are hot topics in IPF research. Oxidative stress and immune cells play a vital role in the pathogenesis of IPF. Our findings suggest the potential of PON2 and TLR4 as novel diagnostic and therapeutic targets for IPF.

Bio-Inspired Carbon Dots as Malondialdehyde Indicator for Real-Time Visualization of Lipid Peroxidation in Depression

Brain lipidic peroxidation is closely associated with the pathophysiology of various psychiatric diseases including depression. Malondialdehyde (MDA), a reactive aldehyde produced in lipid region, serves as a crucial biomarker for lipid peroxidation. However, techniques enabling real-time detection of MDA are still lacking due to the inherent trade-off between recognition dynamics and robustness. Inspired by the structure of phospholipid bilayers, amphiphilic carbon dots named as CG-CDs targeted to cell membrane are designed for real-time monitoring of MDA fluctuations. The design principle relies on the synergy of dynamic hydrogen bonding recognition and cell membrane targetability. The latter facilitates the insertion of CG-CDs into lipid regions and provides a hydrophobic environment to stabilize the labile hydrogen bonding between CG-CDs and MDA. As a result, recognition robustness and dynamics are simultaneously achieved for CG-CDs/MDA, allowing for in situ visualization of MDA kinetics in cell membrane due to the instant response (<5 s), high sensitivity (9-fold fluorescence enhancement), intrinsic reversibility (fluorescence on/off), and superior selectivity. Subsequently, CG-CDs are explored to visualize nerve cell membrane impairment in depression models of living cells and zebrafish, unveiling the extensive heterogeneity of the lipid peroxidation process and indicating a positive correlation between MDA levels and depression.

Glycitein prevents reserpine-induced depression and associated comorbidities in mice: modulation of lipid peroxidation and TNF-α levels

Depression is a debilitating mood disorder affecting millions worldwide and continues to pose a significant global health burden. Due to the multifaceted nature of depression, the current treatment regimens are not up to mark in terms of their multitargeting potential and least side effect profile. Molecules within the isoflavone class demonstrate promising potential in alleviating depression and associated conditions, offering a multifaceted approach to manage mental health concerns. Therefore, the current study was designed to explore the potential of glycitein, an isoflavone in managing reserpine-induced depression and associated comorbidities in mice. Reserpine (0.5 mg/kg; i.p.) administration for the first 3 days induced depression and associated comorbidities as evidenced by increased immobility time in forced swim test (FST) and tail suspension test (TST), along with reduced locomotor activity in the open field test (OFT) and increased latency to reach the platform in the Morris water maze (MWM) test. Reserpine treatment also upregulated and downregulated the brain thiobarbituric acid reactive substance (TBARS) and glutathione (GSH) levels, respectively. Furthermore, reserpine administration also uplifted the level of TNF-α in the serum samples. Glycitein (3 mg/kg and 6 mg/kg; p.o.) treatment for 5 days prevented the depressive effect of reserpine. It also improved the spatial memory at both dose levels. Moreover, in biochemical analysis, glycitein also reduced the brain TBARS and serum tumor necrosis factor-alpha (TNF-α) levels. Whereas, no significant effect was seen on the brain GSH level. Glycitein (6 mg/kg) was found to be more effective than the 3 mg/kg dose of glycitein. Overall results delineate that glycitein has the potential to manage depression and impaired memory by inhibiting lipid peroxidation and inflammatory stress.

Depression and type 2 diabetes: A causal relationship and mechanistic pathway

Depression is a mood disorder that may increase risk for the development of insulin resistance (IR) and type 2 diabetes (T2D), and vice versa. However, the mechanistic pathway linking depression and T2D is not fully elucidated. The aim of this narrative review, therefore, was to discuss the possible link between depression and T2D. The coexistence of T2D and depression is twice as great compared to the occurrence of either condition independently. Hyperglycaemia and dyslipidaemia promote the incidence of depression by enhancing inflammation and reducing brain serotonin (5-hydroxytryptamine [5HT]). Dysregulation of insulin signalling in T2D impairs brain 5HT signalling, leading to the development of depression. Furthermore, depression is associated with the development of hyperglycaemia and poor glycaemic control. Psychological stress and depression promote the development of T2D. In conclusion, T2D could be a potential risk factor for the development of depression through the induction of inflammatory reactions and oxidative stress that affect brain neurotransmission. In addition, chronic stress in depression may induce the development of T2D through dysregulation of the hypothalamic-pituitary-adrenal axis and increase circulating cortisol levels, which triggers IR and T2D.

Enzymatic biomarkers of oxidative stress in patients with depressive disorders. A systematic review

Oxidative stress (OS) results from the imbalance between the production of reactive oxygen species and the body's antioxidant mechanisms and is associated with various diseases, including depression. Antioxidants protect cells by neutralizing free radicals and include enzymatic components such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione S-transferase (GST). The concentration of these biomarkers can quantify OS. This research aimed to gather available information published in the last ten years about the concentration of enzymatic OS biomarkers in samples from patients with depressive disorders.

METHOD

A systematic review was conducted following the PRISMA guidelines, including original scientific articles that evaluated enzymatic OS biomarkers in participants with depressive disorders, using the keywords and boolean operators "superoxide dismutase" OR "catalase" OR "glutathione" AND "depress*" in the databases PubMed, SAGE Journals, DOAJ, Scielo, Dialnet, and Redalyc.

RESULTS

The initial search showed 614 results, with only 28 articles meeting the selection criteria. It was observed that all evaluated oxidative stress enzymatic markers showed a significant increase or decrease in patients with depressive disorders, due to a wide variability in the depressive disorders studied, the type of biological sample analyzed, and the techniques used.

CONCLUSION

There is evidence of the relationship between enzymatic OS biomarkers and depressive disorders, but additional studies are needed to clarify the nature of this relationship, particularly considering the different types of depressive disorders.

Interplay of miRNAs and molecular pathways in spaceflight-induced depression: Insights from a rat model using simulated complex space environment

Depression is a significant concern among astronauts, yet the molecular mechanisms underlying spaceflight-induced depression remain poorly understood. MicroRNAs (miRNAs) have emerged as potential regulators of neuropsychiatric disorders, including depression, but their specific role in space-induced depression remains unexplored. This study aimed to elucidate the involvement of candidate miRNAs (miR-455-3p, miR-206-3p, miR-132-3p, miR-16-5p, miR-124-3p, and miR-145-3p) and their interaction with differentially expressed genes (DEGs) in the neurobiology of spaceflight-induced depressive behavior. Using a simulated space environmental model (SCSE) for 21 days, depressive behavior was induced in rats, and candidate miRNA expressions and DEGs in the cortex region were analyzed through qRT-PCR and HPLC, respectively. Results showed that SCSE-exposed rats exhibited depressive behaviors, including anhedonia, increased immobility, and anxiousness compared to controls. Further analysis revealed increased hydrogen peroxide levels and decreased superoxide dismutase levels in the SCSE group, indicating abnormal oxidative stress in the cerebral cortex. Moreover, miRNA analysis demonstrated significant upregulation of miR-455-3p, miR-206-3p, miR-132-3p, and miR-16-5p expression. Among the DEGs identified, the in silico analysis highlighted their involvement in crucial pathways such as glutamatergic signaling, GABA synaptic pathway, and calcium signaling, implicating their role in spaceflight-induced depression. Protein-protein interaction analysis identified hub genes, including DLG4, DLG3, GRIN1, GRIN2B, GRIN2A, SYNGAP1, DLGAP1, GRIK2, and GRIN3A, impacting neuronal dysfunction functions in the cortex region of SCSE depressive rats. DLG4 emerged as a core gene regulated by miR-455-3p and miR-206-3p. Overall, this study underscores the potential of miRNAs as biomarkers for mood disorders and neurological abnormalities associated with spaceflight, advancing health sciences, and space health care.

Curcumin Reduces Depression in Obese Patients with Type 2 Diabetes: A Randomized Controlled Trial

Type 2 diabetes and depression co-occur in a bidirectional manner. Curcumin supplements exhibit antidepressant effects that may mitigate depression by modulating neurotransmitters and reducing inflammatory and oxidative stress pathways. This study aimed to evaluate the efficacy of curcumin in improving depression severity in obese type 2 diabetes patients. The study employed a randomized, double-blind, placebo-controlled trial design with 227 participants. The primary end-point was depression severity assessed using the Patient Health Questionnaire-9. Biomarkers were measured at baseline and at 3-, 6-, 9-, and 12-month intervals. The biomarkers assessed were serotonin levels, pro-inflammatory cytokines (interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha), antioxidant activities (total antioxidant status, glutathione peroxidase, and superoxide dismutase), and malondialdehyde. After 12 months, the curcumin group exhibited significantly improved depression severity (p = 0.000001). The curcumin group had higher levels of serotonin (p < 0.0001) but lower levels of interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha (p < 0.001 for all) than the placebo group. Total antioxidant status, glutathione peroxidase activity, and superoxide dismutase activity were elevated in the curcumin group, whereas malondialdehyde levels were greater in the placebo group (p < 0.001 for all). These findings suggest curcumin may have antidepressant effects on obese type 2 diabetes patients.

Can exercise benefits be harnessed with drugs? A new way to combat neurodegenerative diseases by boosting neurogenesis

Adult hippocampal neurogenesis (AHN) is affected by multiple factors, such as enriched environment, exercise, ageing, and neurodegenerative disorders. Neurodegenerative disorders can impair AHN, leading to progressive neuronal loss and cognitive decline. Compelling evidence suggests that individuals engaged in regular exercise exhibit higher production of proteins that are essential for AHN and memory. Interestingly, specific molecules that mediate the effects of exercise have shown effectiveness in promoting AHN and cognition in different transgenic animal models. Despite these advancements, the precise mechanisms by which exercise mimetics induce AHN remain partially understood. Recently, some novel exercise molecules have been tested and the underlying mechanisms have been proposed, involving intercommunications between multiple organs such as muscle-brain crosstalk, liver-brain crosstalk, and gut-brain crosstalk. In this review, we will discuss the current evidence regarding the effects and potential mechanisms of exercise mimetics on AHN and cognition in various neurological disorders. Opportunities, challenges, and future directions in this research field are also discussed.

The effects of different durations of exposure to hypomagnetic field on the number of active mitochondria and ROS levels in the mouse hippocampus

Reactive oxygen species (ROS) are one of the potential molecules in response to a hypomagnetic field (HMF), and exposure to an HMF for eight weeks led to an increase in ROS levels in the whole hippocampus area in mice. ROS are mainly derived from the byproducts of mitochondrial metabolism. However, previous in vivo studies mostly focus on the influence of one time point of HMF exposure on the mouse hippocampus and lack comparative studies on the effects of different durations of HMF exposure on the mouse hippocampus. Here, we investigated the effects of different durations of HMF on the number of active mitochondria and ROS levels in mouse hippocampus. Compared with the geomagnetic field (GMF) group, we found that the number of active mitochondria in the hippocampus was significantly reduced during the sixth week of HMF exposure, whereas the number of active mitochondria was significantly reduced and the ROS levels was significantly increased during the eighth week of HMF exposure. The number of active mitochondria gradually decreased and ROS levels gradually increased in both GMF and HMF groups with prolonged exposure time. In addition, the expression level of the PGC-1α gene in the hippocampus, the main regulator of mitochondrial biogenesis, decreased significantly in the eighth week of HMF exposure. These results reveal that the changes in active mitochondria number and ROS levels were dependent on the durations of HMF exposure, and prolonged exposure to HMF exacerbates these changes.

Knocking out Selenium Binding Protein 1 Induces Depressive-Like Behavior in Mice

Selenium binding protein 1 (SELENBP1) is involved in neurologic disorders, such as multiple sclerosis, spinal cord injury, Parkinson's disease, epilepsy, and schizophrenia. However, the role of SELENBP1 in the neurogenesis of depression, which is a neurologic disorder, and the underlying mechanisms of oxidative stress and inflammation in depression remain unknown. In this study, we evaluated the changes in the expression levels of SELENBP1 in the hippocampus of a mouse model of depression and in the serum of human patients with depression using the Gene Expression Omnibus database. These changes were validated using blood samples from human patients with depression and mouse models with chronic unpredictable mild stress (CUMS)-induced depressive-like behavior. We also investigated the effects of SELENBP1 knockout (KO) on inflammation, oxidative stress, and hippocampal neurogenesis in mice with CUMS-induced depression. Our results revealed that SELENBP1 levels was decreased in the blood of human patients with depression and in the hippocampus of mice with CUMS-induced depression. SELENBP1 KO increased CUMS-induced depressive behavior in mice and caused dysregulation of inflammatory cytokines and oxidative stress. This led to a decrease in the numbers of doublecortin- and Ki67-positive cells, which might aggravate CUMS-induced depressive symptoms. These findings suggest that SELENBP1 might be involved in the regulation of neurogenesis in mice with depression and could be served as a potential target for diagnosing and treating depression.

Per- and polyfluoroalkyl substances (PFAS), perceived stress, and depressive symptoms in a prospective cohort study of black women

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are endocrine-disrupting chemicals with neurotoxic properties. PFAS have been associated with depressive symptoms among women in some studies, but little research has evaluated the effects of PFAS mixtures. Further, no study has investigated interactions of PFAS-depression associations by perceived stress, which has been shown to modify the effects of PFAS on other health outcomes.

OBJECTIVE

In a prospective cohort study of reproductive-aged Black women, we investigated associations between PFAS and depressive symptoms and the extent to which perceived stress modified these associations.

METHODS

We analyzed data from 1499 participants (23-35 years) in the Study of Environment, Lifestyle, and Fibroids. We quantified concentrations of nine PFAS in baseline plasma samples using online solid-phase extraction-liquid chromatography-isotope dilution tandem mass spectrometry. Participants reported perceived stress via the Perceived Stress Scale (PSS-4; range = 0-16) at baseline and depressive symptoms via the Center for Epidemiologic Studies Depression Scale (CESD; range = 0-44) at the 20-month follow-up visit. We used Bayesian Kernel Machine Regression to estimate associations between PFAS concentrations, individually and as a mixture, and depressive symptoms, and to assess effect modification by PSS-4 scores, adjusting for confounders.

RESULTS

Baseline perfluorodecanoic acid concentrations were associated with greater depressive symptoms at the 20-month follow-up, but associations for other PFAS were null. The PFAS were not associated with depressive symptoms when evaluated as a mixture. The association between the 90th percentile (vs. 50th percentile) of the PFAS mixture with CES-D scores was null at the 10th (β = 0.03; 95 % CrI = 0.20, 0.25), 50th (β = 0.02; 95 % CrI = -0.16, 0.19), and 90th (β = 0.01; 95 % CrI = 0.18, 0.20) percentiles of PSS-4 scores, suggesting perceived stress did not modify the PFAS mixture.

CONCLUSION

In this prospective cohort study, PFAS concentrations-assessed individually or as a mixture-were not appreciably associated with depressive symptoms, and there was no evidence of effect modification by perceived stress.

Chemical Composition, Antioxidant Activities, Antidepressant Effect, and Lipid Peroxidation of Peruvian Blueberry: Molecular Docking Studies on Targets Involved in Oxidative Stress and Depression

Blueberries (Vaccinium corymbosum L.) are cultivated worldwide and are among the best dietary sources of bioactive compounds with beneficial health effects. This study aimed to investigate the components of Peruvian blueberry using high-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS), identifying 11 compounds. Furthermore, we assessed in vitro the antioxidant activity and in vivo the antidepressant effect using a rat model and protective effect on lipid peroxidation (in the serum, brain, liver, and stomach). We also conducted molecular docking simulations with proteins involved in oxidative stress and depression for the identified compounds. Antioxidant activity was assessed by measuring total phenolic and flavonoid contents, as well as using 1,1-diphenyl-2-picrylhydrazin (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS•+), and ferric-reducing antioxidant power (FRAP) assays. Peruvian blueberries demonstrated higher antioxidant activity than Vaccinium corymbosum fruits from Chile, Brazil, the United States, Turkey, Portugal, and China. The results showed that oral administration of Peruvian blueberries (10 and 20 mg/kg) for 28 days significantly (p < 0.001) increased swimming and reduced immobility in the forced swimming test (FST). Additionally, at doses of 40 and 80 mg/kg, oxidative stress was reduced in vivo (p < 0.001) by decreasing lipid peroxidation in brain, liver, stomach, and serum. Molecular docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions were performed. In the molecular docking studies, quercitrin and 3,5-di-O-caffeoylquinic acid showed the best docking scores for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase, and xanthine oxidase; while 3,5-dicaffeoylquinic acid methyl ester and caffeoyl coumaroylquinic acid had the best docking scores for monoamine oxidase and serotonin receptor 5-HT2. In summary, our results suggest that the antidepressant and protective effects against lipid peroxidation might be related to the antioxidant activity of Peruvian Vaccinium corymbosum L.

Repeated Sulforaphane Treatment Reverses Depressive-like Behavior and Exerts Antioxidant Effects in the Olfactory Bulbectomy Model in Mice

Growing evidence suggests that activators of nuclear factor erythroid-derived 2-like 2 (Nrf2), such as sulforaphane, may represent promising novel pharmacological targets for conditions related to oxidative stress, including depressive disorder. Therefore, we conducted a study to explore the behavioral and biochemical effects of repeated (14 days) sulforaphane (SFN) treatment in the olfactory bulbectomy (OB) animal model of depression. An open field test (OFT), splash test (ST), and spontaneous locomotor activity test (LA) were used to assess changes in depressive-like behavior and the potential antidepressant-like activity of SFN. The OB model induced hyperactivity in mice during the OFT and LA as well as a temporary loss of self-care and motivation in the ST. The repeated administration of SFN (10 mg/kg) effectively reversed these behavioral changes in OB mice across all tests. Additionally, a biochemical analysis revealed that SFN (10 mg/kg) increased the total antioxidant capacity in the frontal cortex and serum of the OB model. Furthermore, SFN (10 mg/kg) significantly enhanced superoxide dismutase activity in the serum of OB mice. Overall, the present study is the first to demonstrate the antidepressant-like effects of repeated SFN (10 mg/kg) treatment in the OB model and indicates that these benefits may be linked to improved oxidative status.

Psychological Distress, Academic Stress, and Burnout among Saudi Undergraduate Nursing Students

Background: There is limited evidence on the association between psychological distress, academic stress, and burnout among Saudi nursing students. Clarifying such an association is crucial to understanding the factors associated with psychological distress and developing interventions to prevent it. Aim: To explore the prevalence and association of psychological distress with academic stress and burnout among Saudi nursing students. Methods: A cross-sectional design was used, and 237 students participated from a nursing college in Riyadh, Saudi Arabia. Students' demographics; the Depression, Anxiety, and Stress Scale; the Academic Stress Inventory; and the Maslach Burnout Inventory were used for data collection. Results: Most of the participants reported no-to-mild depression, anxiety, and stress. Stress related to studying in groups, time management, emotional exhaustion, depersonalization, and personal accomplishment were the significant predictors of psychological distress, explaining 52.1% of the variance. Conclusions: This study suggest implementing tailored mental health screenings and support services for nursing students, embedding mental health professionals in the program, and using telehealth or mobile apps for remote monitoring to ensure comprehensive care for nursing students. Future research should consider these predictors while designing strategies to decrease psychological distress among students.

Possible effect of exercise with anti-fatigue nutrition on ROS-induced depression and suicide risk: a review

PURPOSE

Epidemiological evidence shows that physical activity, including continuous stimulus changes and appropriate exercise programs, improves brain degeneration in the hippocampus, prefrontal cortex (PFC), and anterior cingulate cortex (ACC). Therefore, we investigated the possible synergistic effects of physical activity and nutrition in controlling chronic fatigue and reducing oxidative stress in patients at risk for depression and suicide.

METHODS

We systematically reviewed the literature on various systemic factors related to the effects of 1) suppressing oxidative stress and 2) improving depression through exercise and nutrition. To conduct this review, we searched the PubMed database for papers published until May 1, 2024, using the terms "physical activity OR exercise" and "fatigue" OR "anti-fatigue," "oxidative stress" and "depression" and "suicide." We then reviewed the resulting list of articles related to antioxidant mechanisms.

RESULTS

Appropriate physical activity and natural product intake can substantially change whole-body homeostasis and provide a way to overcome the threat of depression and suicide by regulating metabolites, scavenging free radicals, and neurotransmitters.

CONCLUSION

Suicide and depression prevention play crucial roles in improving patients' quality of life. Our review provides evidence supporting the idea that exercise and antioxidant nutrition diminish oxidative stress and fatigue by improving the degeneration of the hippocampus, PFC, and ACC.

Environmental enrichment and the combined interventions of EE and metformin enhance hippocampal neuron survival and hippocampal-dependent memory in type 2 diabetic rats under stress through the BDNF-TrkB signaling pathways

BACKGROUND

Type 2 diabetes (T2D) with depression causes severe cognitive impairments. The devastating conditions will further compromise the overall quality of life. The overconsumption of high-fat and high-sucrose (HFS) diet is one of the modifiable risk factors for T2D, depression, and cognitive impairments. Thus, it is essential to identify effective therapeutic strategies to overcome the cognitive impairments in T2D with depression. We proposed environmental enrichment (EE) which encompasses social, cognitive, and physical components as the alternative treatment for such impairments. We also investigated the potential neuroprotective properties of the antidiabetic drug metformin. This study aimed to investigate the effects of EE and metformin interventions on hippocampal neuronal death, and hippocampal-dependent memory impairment in T2D rats under stress.

METHODS

Thirty-two male rats (200-250 g) were divided into four groups: C group (standard diet + conventional cage), DS group [HFS-induced T2D + restraint stress (RS)], DSE group [HFS-induced T2D + RS + EE] and DSEM group [HFS + RS + EE + metformin]. Serum corticosterone (CORT) was measured to evaluate stress levels. The serum Free Oxygen Radicals Testing (FORT) and Free Oxygen Radicals Defence Test (FORD) were measured to evaluate the systemic oxidative status (OS). Serum brain-derived neurotrophic factor (BDNF) and T-maze tasks were performed to evaluate cognitive functions. Rats were humanely sacrificed to collect brains for histological, morphometric, and hippocampal gene expression studies.

RESULTS

The CORT and the serum FORT levels in the DSE and DSEM groups were lower than in the DS group. Meanwhile, the serum BDNF, T-maze scores, histological, and morphometric analysis were improved in the DSE and DSEM groups than in the DS group. These findings supported that EE and the combined interventions of EE and metformin had neuroprotective properties. The hippocampal gene expression analysis revealed that the DSE and DSEM groups showed improved regulation of BDNF-TrkB signalling pathways, including the BDNF/TrkB binding, PI3K - Akt pathway, Ras-MAPK pathway, PLCγ-Ca2+ pathway, and CREB transcription.

CONCLUSION

EE and the combined interventions of EE and metformin improved hippocampal neuron survival and hippocampal-dependent memory in T2D rats under stress by enhancing gene expression regulation of neurogenesis and synaptic plasticity.

Pharmacological investigation of taxifolin for its therapeutic potential in depression

The current study aimed to investigate the influence of taxifolin on depression symptoms alleviation in Male Sprague-Dawley rats by targeting underlying pathways of depression. Molecular docking analyses were conducted to validate taxifolin's binding affinities against various targets. In silico analysis of taxifolin revealed various aspects of post docking interactions with different protein targets. Depression was induced in rats via intraperitoneal injection of Lipopolysaccharide (LPS; 500 μ g/Kg) for 14 alternative days. Rats (n = 6/group) were randomly assigned to four groups: (i) Saline/Control, (ii) Disease (LPS 500 μg/kg), (iii) Standard (fluoxetine 20 mg/kg), and (iv) Treatment (taxifolin 20 mg/kg). At the end of the in vivo study, brain samples were used for biochemical and morphological analysis. Taxifolin exhibited neuroprotective effects, as evidenced by behavioral studies, antioxidant analysis, histopathological examination, immunohistochemistry, ELISA and RT PCR, indicating an increase number of surviving neurons, normalization of cell size and shape, and reduction in vacuolization. Taxifolin also decreased inflammatory markers such as TNF-α, NF-κb, IL-6 and COX-2, while significantly upregulating and activating the protective PPAR-γ pathway, through which it reduces the oxidative stress, neuroinflammation, neurodegeneration, thereby ameliorating depression symptoms in experimental rat model of depression. Our finding suggests that taxifolin act as neuroprotective agent partially mediated through PPAR-γ pathway.

Pro-inflammatory cytokines in stress-induced depression: Novel insights into mechanisms and promising therapeutic strategies

Stress-mediated depression is one of the common psychiatric disorders with a high prevalence and suicide rate, there is a lack of effective treatment. Accordingly, effective treatments with few adverse effects are urgently needed. Pro-inflammatory cytokines (PICs) may play a key role in stress-mediated depression. Thereupon, both preclinical and clinical studies have found higher levels of IL-1β, TNF-α and IL-6 in peripheral blood and brain tissue of patients with depression. Recent studies have found PICs cause depression by affecting neuroinflammation, monoamine neurotransmitters, hypothalamic pituitary adrenal axis and neuroplasticity. Moreover, they play an important role in the symptom, development and progression of depression, maybe a potential diagnostic and therapeutic marker of depression. In addition, well-established antidepressant therapies have some relief on high levels of PICs. Importantly, anti-inflammatory drugs relieve depressive symptoms by reducing levels of PICs. Collectively, reducing PICs may represent a promising therapeutic strategy for depression.

Behavioural and physiological responses to stressors in sheep with temperament classified by genotype or phenotype

The single nucleotide polymorphism (SNP) rs107856856, located in the tryptophan hydroxylase-2 gene, is associated with the behavioural phenotype for sheep temperament measured at weaning. Here, we tested the association between that SNP and physiological and behavioural responses to stressors in adult sheep. Two groups of adult sheep, one with genotype A/A (calm genotype) and the other with G/G (nervous genotype) in rs107856856, were selected from 160 sheep and were exposed, twice, to an open-field arena and an isolation box test (IBT). During each repeat, the behaviour and physiological responses (cortisol, prolactin, dehydroepiandrosterone [DHEA], brain derived neurotrophic factor [BDNF], characteristics of the response of body temperature, and oxidative stress) were measured. The behavioural and physiological responses of the sheep were compared between genotypes and also between groups classified on their phenotype as assessed by their initial isolation box score ("low responders" and "high responders"). The SNP rs107856856 had some effects on the behavioural phenotype (IBT score) but no effects on the physiological response to stress (cortisol, prolactin, DHEA, BDNF, oxidative stress or changes in body temperature) in the adult sheep, probably because the sheep were exposed, and therefore had adapted, to human contact during their life.

Role of brain renin-angiotensin system in depression: A new perspective

Depression is a mood disorder characterized by abnormal thoughts. The pathophysiology of depression is related to the deficiency of serotonin (5HT), which is derived from tryptophan (Trp). Mitochondrial dysfunction, oxidative stress, and neuroinflammation are involved in the pathogenesis of depression. Notably, the renin-angiotensin system (RAS) is involved in the pathogenesis of depression, and different findings revealed that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) may be effective in depression. However, the underlying mechanism for the role of dysregulated brain RAS-induced depression remains speculative. Therefore, this review aimed to revise the conceivable role of ACEIs and ARBs and how these agents ameliorate the pathophysiology of depression. Dysregulation of brain RAS triggers the development and progression of depression through the reduction of brain 5HT and expression of brain-derived neurotrophic factor (BDNF) and the induction of mitochondrial dysfunction, oxidative stress, and neuroinflammation. Therefore, inhibition of central classical RAS by ARBS and ACEIs and activation of non-classical RAS prevent the development of depression by regulating 5HT, BDNF, mitochondrial dysfunction, oxidative stress, and neuroinflammation.

Investigating the Mechanism of Chufan Yishen Formula in Treating Depression through Network Pharmacology and Experimental Verification

Objective: To investigate the antidepressant effect and potential mechanism of the Chufan Yishen Formula (CFYS) through network pharmacology, molecular docking, and experimental verification. Methods: The active ingredients and their target genes of CFYS were identified through Traditional Chinese Medicine Systems Pharmacology (TCMSP) and TCM-ID. We obtained the differentially expressed genes in patients with depression from the GEO database and screened out the genes intersecting with the target genes of CFYS to construct the PPI network. The key pathways were selected through STRING and KEGG. Then, molecular docking and experimental verification were performed. Results: A total of 113 effective components and 195 target genes were obtained. After intersecting the target genes with the differentially expressed genes in patients with depression, we obtained 37 differential target genes, among which HMOX1, VEGFA, etc., were the key genes. After enriching the differential target genes by KEGG, we found that the "chemical carcinogenesis-reactive oxygen species" pathway was the key pathway for the CFYS antidepressant effect. Besides, VEGFA might be a key marker for depression. Experimental verification found that CFYS could significantly improve the behavioral indicators of rats with depression models, including improving the antioxidant enzyme activity and increasing VEGFA levels. The results are consistent with the network pharmacology analysis. Conclusions: CFYS treatment for depression is a multicomponent, multitarget, and multipathway complex process, which may mainly exert an antidepressant effect by improving the neuron antioxidant stress response and regulating VEGFA levels.

A Curcumin-Decorated Nanozyme with ROS Scavenging and Anti-Inflammatory Properties for Neuroprotection

Disordered reactive oxygen/nitrogen species are a common occurrence in various diseases, which usually cause cellular oxidative damage and inflammation. Despite the wide range of applications for biomimetic nanoparticles with antioxidant or anti-inflammatory properties, designs that seamlessly integrate these two abilities with a synergistic effect in a simple manner are seldom reported. In this study, we developed a novel PEI-Mn composite nanoparticle (PM NP) using a chelation method, and the curcumin was loaded onto PM NPs via metal-phenol coordination to form PEI-Mn@curcumin nanoparticles (PMC NPs). PMC NPs possessed excellent dispersibility and cytocompatibility, was engineered to serve as an effective nanozyme, and exhibited specific SOD-like and CAT-like activities. In addition, the incorporation of curcumin granted PMC NPs the ability to effectively suppress the expression of inflammatory cytokines in microglia induced by LPS. As curcumin also has antioxidant properties, it further amplified the synergistic efficiency of ROS scavenging. Significantly, PMC NPs effectively scavenged ROS triggered by H2O2 in SIM-A9 microglia cells and Neuro-2a cells. PMC NPs also considerably mitigated DNA and lipid oxidation in Neuro-2a cells and demonstrated an increase in cell viability under various H2O2 concentrations. These properties suggest that PMC NPs have significant potential in addressing excessive ROS and inflammation related to neural diseases.

Unique pathways downstream of TLR-4 and TLR-7 activation: sex-dependent behavioural, cytokine, and metabolic consequences

Introduction

Post-infection syndromes are characterised by fatigue, muscle pain, anhedonia, and cognitive impairment; mechanistic studies exploring these syndromes have focussed on pathways downstream of Toll-like receptor (TLR) 4 activation. Here, we investigated the mechanistic interplay between behaviour, metabolism, and inflammation downstream of TLR-7 activation compared to TLR-4 activation in male and female CD1 mice.

Methods

Animals received either a TLR-4 (LPS; 0.83 mg/kg) or TLR-7 (R848, 5 mg/kg) agonist, or saline, and behaviour was analysed in an Open Field (OF) at 24 h (n = 20/group). Plasma, liver, and prefrontal cortex (PFC) were collected for gene expression analysis at 24 h and 1H-NMR metabolomics.

Results

TLR-4 and TLR-7 activation decreased distance travelled and rearing in the OF, but activation of each receptor induced distinct cytokine responses and metabolome profiles. LPS increased IL-1β expression and CXCL1 in the PFC, but TLR7 activation did not and strongly induced PFC CXCL10 expression. Thus, TLR7 induced sickness behaviour is independent of IL-1β expression. In both cases, the behavioural response to TLR activation was sexually dimorphic: females were more resilient. However, dissociation was observed between the resilient female mice behaviour and the levels of gene cytokine expression, which was, in general, higher in the female mice. However, the metabolic shifts induced by immune activation were better correlated with the sex-dependent behavioural dimorphisms; increased levels of antioxidant potential in the female brain are intrinsic male/female metabolome differences. A common feature of both TLR4 and TLR7 activation was an increase in N-acetyl aspartate (NAA) in the PFC, which is likely be an allostatic response to the challenges as sickness behaviour is inversely correlated with NAA levels.

Discussion

The results highlight how the cytokine profile induced by one PAMP cannot be extrapolated to another, but they do reveal how the manipulation of the conserved metabolome response might afford a more generic approach to the treatment of post-infection syndromes.

Systematic review and meta-analysis of the effects of exercise on cognitive impairment and neuroprotective mechanisms in diabetes mellitus animal models

This study aims to assess the effects of exercise on cognitive impairment behavioral performance and neuroprotective mechanisms in diabetes mellitus (DM) animal models. PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Database (VIP), and China Biomedical Literature Database (CBM) were systematically searched for studies investigating the impact of exercise on cognitive impairment in animal models of diabetes mellitus (DM) from the inception of these databases through July 2023. Rigorous quality assessments were conducted on the included literature. Primary outcome measures comprised fasting blood glucose (FBG) levels and performance in the Morris water maze test, while secondary outcomes focused on mechanisms related to neuroprotection. Statistical analysis of outcome data was conducted using RevMan 5.3 and R software. A total of 17 studies were included, encompassing 399 animals. The results of the meta-analysis of primary outcome measures revealed that, compared to the control group, exercise effectively reduced fasting blood glucose (FBG) levels in diabetic animal models. In the Morris water maze experiment, exercise also significantly decreased the escape latency of diabetic animal models, increased the number of platform crossings, improved the percentage of time spent in the target quadrant, extended the time spent in the target quadrant, and enhanced swimming speed. Meta-analysis of secondary outcome measures indicated that exercise effectively reduced Aβ deposition, attenuated oxidative stress, enhanced synaptic function, suppressed cellular apoptosis and neuroinflammation, and promoted neurogenesis. Exercise represents a promising non-pharmacological therapy with a positive impact on diabetes-related cognitive function and neuroprotection. Moreover, this study provides a theoretical foundation for further preclinical and clinical trials.

Moving to Improve Mental Health - The Role of Exercise in Cognitive Function: A Narrative Review

This review study investigates how exercise can enhance cognitive ability and mental wellness. Physical activity has been linked to a number of beneficial effects on cognitive function, including increased memory and executive function in adults, improved academic performance in children and adolescents, and potential advantages for people with cognitive impairments or neurodegenerative diseases. Increased cerebral blood flow, the synthesis of neurotrophic factors, and a decrease in oxidative stress and inflammation are the processes driving these effects. Studies have shown that exercise has mood-regulating benefits, with symptoms of anxiety and sadness lessening as a result. These mood-enhancing effects are a result of the endocannabinoid system being activated, endorphins being released, and changes in self-esteem and body image. Exercise therapies have also demonstrated the potential to encourage cognitive health as people age and lower the likelihood of cognitive decline. Exercise has been investigated as an adjuvant treatment for mental health illnesses, such as depression, anxiety disorders, schizophrenia, bipolar disorder, and eating disorders, in addition to its preventive effects. Exercise can improve the effectiveness of treatment and general wellbeing when it is incorporated into comprehensive treatment strategies. To identify the ideal exercise parameters for certain outcomes and overcome barriers to exercise participation, more study is necessary. We can get closer to enhancing general wellbeing and quality of life by including exercise in measures for promoting mental health and cognitive health.

Neuroprotective potential of Afzelin: A novel approach for alleviating catalepsy and modulating Bcl-2 expression in Parkinson's disease therapy

The lost dopaminergic neurons in the brain prevent mobility in Parkinson's disease (PD). It is impossible to stop the disease's progress by means of symptoms management. Research focuses on oxidative stress, mitochondrial dysfunction, and neuronal degeneration. Exploration of potential neuroprotective drugs against prosurvival B-cell lymphoma 2 (Bcl-2) protein is ongoing. An investigable cause behind PD, as well as preventive measures, could be discovered considering the association between such behavioural manifestations (cataleptic behaviours) and PD. The compound Afzelin, known to guard the nervous system, was chosen for this study. The study was done on rats divided into six different groups. First, there was a control group. The other group was treated with Reserpine (RES) (1 mg/kg). The third group received RES (1 mg/kg) and levodopa (30 mg/kg). The remaining three groups were given RES (1 mg/kg) in conjunction with Afzelin at the following doses: 5 mg/kg, 10 mg/kg, and 20 mg/kg. Cataleptic behavior and mobility in rats was assessed using the rotarod, open field, and modified forced-swim tests. thiobarbituric acid reactive substances (TBARS), nitric oxide (NO), biogenic amines, and Bcl-2 level in rat tissue homogenates were considered. According to the study's findings, the rats treated through co-administration of RES and Afzelin improved significantly in their cataleptic behaviours and locomotor activity. In addition, administering Afzelin itself caused Bcl-2 expression, which could have some neuroprotection properties. This study provides meaningful information on the effectiveness of Afzelin in handling catalepsy and other degenerative neurologic disorders. As a result, other studies need to be conducted to establish the reasons behind the reactions and determine the long-term effects of Afzelin on these conditions.

Menopause-Associated Depression: Impact of Oxidative Stress and Neuroinflammation on the Central Nervous System-A Review

Perimenopausal depression, occurring shortly before or after menopause, is characterized by symptoms such as emotional depression, anxiety, and stress, often accompanied by endocrine dysfunction, particularly hypogonadism and senescence. Current treatments for perimenopausal depression primarily provide symptomatic relief but often come with undesirable side effects. The development of agents targeting the specific pathologies of perimenopausal depression has been relatively slow. The erratic fluctuations in estrogen and progesterone levels during the perimenopausal stage expose women to the risk of developing perimenopausal-associated depression. These hormonal changes trigger the production of proinflammatory mediators and induce oxidative stress, leading to progressive neuronal damage. This review serves as a comprehensive overview of the underlying mechanisms contributing to perimenopausal depression. It aims to shed light on the complex relationship between perimenopausal hormones, neurotransmitters, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression. By summarizing the intricate interplay between hormonal fluctuations, neurotransmitter activity, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression, this review aims to stimulate further research in this field. The hope is that an increased understanding of these mechanisms will pave the way for the development of more effective therapeutic targets, ultimately reducing the risk of depression during the menopausal stage for the betterment of psychological wellbeing.

Mechanistic interplay of different mediators involved in mediating the anti-depressant effect of isoflavones

Depression is one of the most prevalent severe CNS disorders, which negatively affects social lives, the ability to work, and the health of people. As per the World Health Organisation (WHO), it is a psychological disorder that is estimated to be a leading disease by 2030. Clinically, various medicines have been formulated to treat depression but they are having a setback due to their side effects, slow action, or poor bioavailability. Nowadays, flavonoids are regarded as an essential component in a variety of nutraceutical, pharmaceutical and medicinal. Isoflavones are a distinctive and important subclass of flavonoids that are generally obtained from soybean, chickpeas, and red clover. The molecules of this class have been extensively explored in various CNS disorders including depression and anxiety. Isoflavones such as genistein, daidzein, biochanin-A, formononetin, and glycitein have been reported to exert an anti-depressant effect through the modulation of different mediators. Fatty acid amide hydrolase (FAAH) mediated depletion of anandamide and hypothalamic-pituitary-adrenal (HPA) axis-mediated modulation of brain-derived neurotrophic factor (BDNF), monoamine oxidase (MAO) mediated depletion of biogenic amines and inflammatory signaling are the important underlying pathways leading to depression. Upregulation in the levels of BDNF, anandamide, antioxidants and monoamines, along with inhibition of MAO, FAAH, HPA axis, and inflammatory stress are the major modulations produced by different isoflavones in the observed anti-depressant effect. Therefore, the present review has been designed to explore the mechanistic interplay of various mediators involved in mediating the anti-depressant action of different isoflavones.

Interplay of G-proteins and Serotonin in the Neuroimmunoinflammatory Model of Chronic Stress and Depression: A Narrative Review

INTRODUCTION

This narrative review addresses the clinical challenges in stress-related disorders such as depression, focusing on the interplay between neuron-specific and pro-inflammatory mechanisms at the cellular, cerebral, and systemic levels.

OBJECTIVE

We aim to elucidate the molecular mechanisms linking chronic psychological stress with low-grade neuroinflammation in key brain regions, particularly focusing on the roles of G proteins and serotonin (5-HT) receptors.

METHODS

This comprehensive review of the literature employs systematic, narrative, and scoping review methodologies, combined with systemic approaches to general pathology. It synthesizes current research on shared signaling pathways involved in stress responses and neuroinflammation, including calcium-dependent mechanisms, mitogen-activated protein kinases, and key transcription factors like NF-κB and p53. The review also focuses on the role of G protein-coupled neurotransmitter receptors (GPCRs) in immune and pro-inflammatory responses, with a detailed analysis of how 13 of 14 types of human 5-HT receptors contribute to depression and neuroinflammation.

RESULTS

The review reveals a complex interaction between neurotransmitter signals and immunoinflammatory responses in stress-related pathologies. It highlights the role of GPCRs and canonical inflammatory mediators in influencing both pathological and physiological processes in nervous tissue.

CONCLUSION

The proposed Neuroimmunoinflammatory Stress Model (NIIS Model) suggests that proinflammatory signaling pathways, mediated by metabotropic and ionotropic neurotransmitter receptors, are crucial for maintaining neuronal homeostasis. Chronic mental stress can disrupt this balance, leading to increased pro-inflammatory states in the brain and contributing to neuropsychiatric and psychosomatic disorders, including depression. This model integrates traditional theories on depression pathogenesis, offering a comprehensive understanding of the multifaceted nature of the condition.

Serotonin-related Mechanisms in the Etiology and Pharmacotherapy of Social Phobia, A Review

Social anxiety disorder (SAD), known as social phobia, is considered a prevalent psychiatric disorder characterized by a constant fear of social positions. Frequently, social phobia occurs with other mental disorders including depression and substance abuse conditions. Although SAD is considered one of the most common types of mental disorders, proper management may be compromised in recurrent psychiatric comorbidity due to clinicians' focus on secondary complications. Moreover, despite the description of social phobia as a polygenic and complex condition, few altered genetic and epigenetic factors are identified as causative agents. Over the past decades, several studies have suggested polymorphisms in serotonergic and dopaminergic-related genes as the etiology of social phobia. Serotonin, on the other hand, as a necessary neurotransmitter in the central nervous system (CNS), is involved in a variety of disease processes including social phobia. Nevertheless, the exact mechanism of serotonin-dependent development of the disease and the efficacy of suggested pharmacotherapies are not fully understood. The current study aimed to review the serotonin-dependent mechanisms by which SAD develops and discuss the current suggested strategies that are based on serotonin metabolism.

Promising new pharmacological targets for depression: The search for efficacy

Pharmacological treatment of major depressive disorder (MDD) still relies on the use of serotonergic drugs, despite their limited efficacy. A few mechanistically new drugs have been developed in recent years, but many fail in clinical trials. Several hypotheses have been proposed to explain MDD pathophysiology, indicating that physiological processes such as neuroplasticity, circadian rhythms, and metabolism are potential targets. Here, we review the current state of pharmacological treatments for MDD, as well as the preclinical and clinical evidence for an antidepressant effect of molecules that target non-serotonergic systems. We offer some insights into the challenges facing the development of new antidepressant drugs, and the prospect of finding more effectiveness for each target discussed.

Mitochondrial Interaction with Serotonin in Neurobiology and Its Implication in Alzheimer's Disease

Alzheimer's disease (AD) is a lethal neurodegenerative disorder characterized by severe brain pathologies and progressive cognitive decline. While the exact cause of this disease remains unknown, emerging evidence suggests that dysregulation of neurotransmitters contributes to the development of AD pathology and symptoms. Serotonin, a critical neurotransmitter in the brain, plays a pivotal role in regulating various brain processes and is implicated in neurological and psychiatric disorders, including AD. Recent studies have shed light on the interplay between mitochondrial function and serotonin regulation in brain physiology. In AD, there is a deficiency of serotonin, along with impairments in mitochondrial function, particularly in serotoninergic neurons. Additionally, altered activity of mitochondrial enzymes, such as monoamine oxidase, may contribute to serotonin dysregulation in AD. Understanding the intricate relationship between mitochondria and serotonin provides valuable insights into the underlying mechanisms of AD and identifies potential therapeutic targets to restore serotonin homeostasis and alleviate AD symptoms. This review summarizes the recent advancements in unraveling the connection between brain mitochondria and serotonin, emphasizing their significance in AD pathogenesis and underscoring the importance of further research in this area. Elucidating the role of mitochondria in serotonin dysfunction will promote the development of therapeutic strategies for the treatment and prevention of this neurodegenerative disorder.

Evaluation of Thiol/Disulfide Interrelation in Major Depressive Disorder

Objective

Although major depressive disorder (MDD) constitutes a significant part of mental health problems, its pathogenesis has not been fully elucidated. The inadequacy of diagnostic tests specific to MDD causes difficulty in diagnosis. Therefore, we investigated the situation of thiol/disulfide imbalance, which may play a role in the pathogenesis of many diseases, in MDD patients.

Methods

Forty-five MDD patients and 40 non-patient volunteers participated in our study. Sociodemographic data form, Beck Depression Scale, and Clinical Global Impression Scale were used in making the diagnosis and evaluation process.

Results

There was a significant difference between the MDD and non-patient groups in native thiol and total thiol levels, disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios. No significant difference was detected in terms of disulfide level between the 2 groups. There was no significant difference between the patients' thiol disulfide ratios and the severity of depression. There was no significant difference between the patients' symptom duration and thiol disulfide ratios. Nevertheless, a negative correlation was identified between the duration of the patients' symptoms and their disulfide levels.

Conclusion

When the results were examined in terms of thiol and disulfide ratios, they showed that thiol and disulfide ratios were impaired in depression. We think that thiol/disulfide parameters may be a biomarker candidate that can help in the diagnosis of MDD.