Zinc, future mono/adjunctive therapy for depression: Mechanisms of antidepressant action

Exploring Zn(II)-Acetyl l-carnitine complex for simultaneous management of depression, chronic pain, and neuroprotection

Acetyl-l-carnitine (ALC) is synthesized in the brain, liver, and kidneys and plays crucial roles in energy metabolism, acetylcholine production, protein synthesis, and neuronal protection, contributing to its antidepressant and neuroprotective properties. Zinc, a vital biometal, is essential for depression and neuroprotection, exhibiting antidepressive effects alone or combined with classical antidepressants. The pharmacological benefits of metal coordination complexes often result from synergistic or additive effects. In this study, we present a novel multifunctional zinc complex, Zn(ALC)Cl2(H2O), which crystallizes in the monoclinic chiral space group P21, featuring a distorted tetrahedral Zn(II) environment. This new compound demonstrates significantly higher antidepressant activity, reducing immobility in the forced swimming test by 54 % compared to commercial ALC. Additionally, it exhibits in vivo antinociceptive properties, increases latency time, and proves effective in a diabetic neuropathy model by preventing the glucose-induced decrease in intracellular GSH levels. In vitro studies indicate that the complex can cross the blood-brain barrier and offer neuroprotection against glutamate-induced excitotoxicity and oxygen-glucose deprivation, with a drug classification of 10 versus 5 for ALC. Furthermore, under astrocytosis conditions, the Zn complex neutralizes the toxic effects of TGFβ-treated astrocytes. These findings highlight Zn(ALC)Cl2(H2O) as a promising candidate for treating depression and neurodegenerative diseases.

Dissociative Identity Disorder Cotreated With Zinc and L-carnosine: A Case Report

Little is known about the effectiveness of pharmacotherapy in dissociative identity disorder (DID). Zinc is essential for proper brain function. Its deficiency can lead to mental health symptoms, possibly contributing to dissociation. L-carnosine is an endogenous dipeptide with a neuroprotective effect. We report on the case of a 30-year-old woman with DID and comorbid bipolar I disorder who had zinc deficiency and was successfully cotreated with zinc and L-carnosine. She displayed three alternate identities and exhibited signs of emotional/mood instability, flashbacks, binge eating, and self-harm. The patient also displayed several physical symptoms of zinc deficiency. She did not respond to aripiprazole (0.75 mg/d) and clonazepam (1.5 mg/d), but responded marginally to five months of zinc (50 mg/d) supplementation. Simultaneous administration of L-carnosine, gradually increased from 0.5 g/d to 2 g/d over four months, markedly improved her symptoms. Five months after adding 2 g/d L-carnosine, the patient's pronounced alternate identities that people around her could notice no longer appeared. However, the identities that were not noticeable to the people remained. They disappeared completely two years later and reappeared only when zinc and L-carnosine were discontinued during the subsequent three-year follow-up. The patient's severity scores for dissociation and depression were reduced. Furthermore, signs of emotional/mood instability, flashbacks, binge eating, and self-harm improved. The physical symptoms of zinc deficiency eventually resolved. Further investigation of cotreatment with zinc and L-carnosine for DID and related conditions, particularly the contribution of zinc deficiency to dissociation, is necessary.

Binary effects of fluoxetine and zinc on the biomarker responses of the non-target model organism Daphnia magna

The antidepressant effect of zinc on mammals has been documented in recent decades, and the concentration of the antidepressant fluoxetine (FLX) in aquatic environments has been rising constantly. The aim of the present study is to evaluate the combined toxicity of a serotonin reuptake inhibitor (FLX) and Zn2+ on a non-target aquatic model organism Daphnia magna. Animals were exposed to single and binary combinations of FLX (20.5 and 41 µg/L for subchronic and 41 and 82 µg/L for acute exposures) and Zn2+ (40 µg/L for subchronic and 80 µg/L for acute exposures). In vivo experiments were done for 7 days subchronic and 48 h acute exposure, while subcellular supernatants of whole Daphnia lysate (WDL) were directly treated with the same concentrations used in the acute experiments. Morphological characteristics, Ca2+-ATPase, antioxidant enzyme activities, and lipid peroxidation were examined. There was antioxidant system suppression and Ca2+-ATPase inhibition despite the diverse response patterns due to duration, concentration, and toxicant type. After acute exposure, biomarkers showed a diminishing trend compared to subchronic exposure. According to integrated biomarker response index (IBR) analysis, in vivo Zn2+ exposure was reasonably effective on the health of D. magna, whereas exposure of WDL to Zn2+ had a lesser impact. FLX toxicity increased in a concentration-dependent manner, reversed by the combined exposure. We concluded that potential pro-oxidative and adverse Ca2+-ATPase effects of FLX and Zn2+ in D. magna may also have harmful impact on ecosystem levels. Pharmaceutical exposure (FLX) should be considered along with their potential to interact with other toxicants in aquatic biota.

Evaluation of Antidepressive-like Behaviours and Oxidative Stress Parameters in Mice Receiving Imipramine-Zinc Complex Compound

The study aimed to evaluate the antidepressant-like effects of an imipramine-zinc (IMI-Zn) complex compound on mice and assess the level of oxidative stress parameters. The research also investigated whether the IMI-Zn complex showed superior antidepressant activity compared to individual treatments of both compounds at effective doses and their joint administration at subtherapeutic doses. The study was conducted on mice. Forced swim (FST), tail suspension (TST), and locomotor activity tests were used for behavioral studies. The results demonstrated the IMI-Zn complex's dose-dependent antidepressant potential when orally administered to mice. Its efficacy was similar to the separate administration of therapeutic doses of imipramine (IMI) and zinc (Zn) and their joint administration at subtherapeutic doses. Moreover, subjecting mice to acute stress did not significantly affect the activity of on glutathione peroxidase (GPX), glutathione reductase (GR), and total antioxidant status (TAS), possibly due to the short exposure time to the stress stimulus. By developing the IMI-Zn complex, it might be possible to simplify the treatment approach, potentially improving patient compliance by combining the therapeutic effects of both IMI and Zn within a single compound, thus addressing one of the contributing factors to non-compliance in depression therapy. The IMI-Zn complex could be a valuable strategy to optimize therapeutic outcomes and balance efficacy and tolerability.

Are the epigenetic changes predictive of therapeutic efficacy for psychiatric disorders? A translational approach towards novel drug targets

The etiopathogenesis of mental disorders is not fully understood and accumulating evidence support that clinical symptomatology cannot be assigned to a single gene mutation, but it involves several genetic factors. More specifically, a tight association between genes and environmental risk factors, which could be mediated by epigenetic mechanisms, may play a role in the development of mental disorders. Several data suggest that epigenetic modifications such as DNA methylation, post-translational histone modification and interference of microRNA (miRNA) or long non-coding RNA (lncRNA) may modify the severity of the disease and the outcome of the therapy. Indeed, the study of these mechanisms may help to identify patients particularly vulnerable to mental disorders and may have potential utility as biomarkers to facilitate diagnosis and treatment of psychiatric disorders. This article summarizes the most relevant preclinical and human data showing how epigenetic modifications can be central to the therapeutic efficacy of antidepressant and/or antipsychotic agents, as possible predictor of drugs response.

Alterations of Serum Magnesium Concentration in Animal Models of Seizures and Epilepsy—The Effects of Treatment with a GPR39 Agonist and Knockout of the Gpr39 Gene

Several ligands have been proposed for the GPR39 receptor, including the element zinc. The relationship between GPR39 and magnesium homeostasis has not yet been examined, nor has such a relationship in the context of seizures/epilepsy. We used samples from mice that were treated with an agonist of the GPR39 receptor (TC-G 1008) and underwent acute seizures (maximal electroshock (MES)- or 6-hertz-induced seizures) or a chronic, pentylenetetrazole (PTZ)-induced kindling model of epilepsy. MES seizures and PTZ kindling, unlike 6 Hz seizures, increased serum magnesium concentration. In turn, Gpr39-KO mice that underwent PTZ kindling displayed decreased concentrations of this element in serum, compared to WT mice subjected to this procedure. However, the levels of expression of TRPM7 and SlC41A1 proteins—which are responsible for magnesium transport into and out of cells, respectively—did not differ in the hippocampus between Gpr39-KO and WT mice. Furthermore, laser ablation inductively coupled plasma mass spectrometry applied to hippocampal slices did not reveal differences in magnesium levels between the groups. These data show the relationship between magnesium homeostasis and certain types of acute or chronic seizures (MES seizures or PTZ kindling, respectively), but do not explicitly support the role of GPR39 in mediating magnesium balance in the hippocampus in the latter model. However, decreased expression of TRPM7 and increased expression of SLC41A1—which were observed in the hippocampi of Gpr39-KO mice treated with TC-G 1008, in comparison to WT mice that received the same treatment—implicitly support the link between GPR39 and hippocampal magnesium homeostasis.

Antidepressant-like Effects of Combined Fluoxetine and Zinc Treatment in Mice Exposed to Chronic Restraint Stress Are Related to Modulation of Histone Deacetylase

Chronic stress is the key factor contributing to the development of depressive symptoms. Chronic restraint stress (CRS) is well validated and is one of the most commonly used models to induce depressive-like behavior in rodents. The present study aimed to evaluate whether fluoxetine (FLU 5 mg/kg) and zinc (Zn 10mg/kg) given simultaneously induce a more pronounced antidepressant-like effect in the CRS model than both those compounds given alone. Behavioral assessment was performed using the tail suspension and splash tests (TST and ST, respectively). Furthermore, the effects of CRS, FLU and Zn given alone and combined treatment with FLU + Zn on the expression of proteins involved in the apoptotic, inflammatory, and epigenetic processes were evaluated in selected brain structures (prefrontal cortex, PFC; and hippocampus, Hp) using Western blot analysis or enzyme-linked immunosorbent assays (ELISA). The results obtained indicated that three hours (per day) of immobilization for 4 weeks induced prominent depressive symptoms that manifested as increased immobility time in the TST, as well as decreased number and grooming time in the ST. Behavioral changes induced by CRS were reversed by both FLU (5 and 10 mg/kg) or Zn (10 mg/kg). Zinc supplementation (10 mg/kg) slightly increases the effectiveness of FLU (5 mg/kg) in the TST. However, it significantly increased the activity of FLU in the ST compared to the effect induced by FLU and Zn alone. Biochemical studies revealed that neither CRS nor FLU and Zn given alone or in combined treatment alter the expression of proteins involved in apoptotic or inflammatory processes. CRS induced major alterations in histone deacetylase (HDAC) levels by increasing the level of HADC1 and decreasing the level of HADC4 in the PFC and Hp, decreasing the level of HADC6 in the PFC but increasing it in Hp. Interestingly, FLU + Zn treatment reversed CRS-induced changes in HDAC levels in the Hp, indicating that HDAC modulation is linked to FLU + Zn treatment and this effect is structure-specific.

Anorexia Nervosa-What Has Changed in the State of Knowledge about Nutritional Rehabilitation for Patients over the Past 10 Years? A Review of Literature

Anorexia nervosa (AN) is a psycho-metabolic disorder with a high risk of somatic complications such as refeeding syndrome (RFS) and carries the highest mortality rate of all psychiatric illnesses. To date, the consensus on the care for patients with AN has been based on recommendations for a combination of alimentation and psychotherapy. It is important to establish an initial caloric intake that will provide weight gain and minimize the risk of complications in the treatment of undernourished patients. Research over the past few years suggests that current treatment recommendations may be too stringent and should be updated. The aim of this paper is to systematize the current reports on nutritional rehabilitation in AN, to present the results of studies on the safe supplementation of patients and its potential impact on improving prognosis and the healing process. This review of literature, from 2011-2021, describes the changing trend in the nutritional protocols used and the research on their efficacy, safety, and long-term effects. In addition, it presents previous reports on the potential benefits of introducing vitamin, pro-and prebiotic and fatty acid supplementation.

Nutrition, Exercise, and Stress Management for Treatment and Prevention of Psychiatric Disorders. A Narrative Review Psychoneuroendocrineimmunology-Based

Psychoneuroendocrineimmunology (PNEI) brings together knowledge acquired since the 1930s from endocrinology, immunology, neuroscience, and psychology. With PNEI, a model of research and interpretation of health and disease is emerging, which sees the human body as a structured and interconnected unit, where the psychological and biological systems are mutually coordinated. In the PNEI view, many factors could influence mental health, with the endocrine system involved in mediating the effects of environmental stress on mental health and inflammation in the onset and course of psychiatric disorders as a result of individual and collective conditions and behaviors. Among these, nutrition is one way by which the environment impacts physiology: indeed, many pieces of research showed that several elements (e.g., probiotics, fish oil, zinc) have a positive effect on mental disorders thus being potentially augmentation agents in treatment. Still, physical activity can moderate depressive symptoms, while prolonged stress increases the risk of psychopathology. Taken together, the PNEI-based approach may inform prevention and treatment strategies, also in the field of mental health care.

Zinc as an adjunct to antidepressant medication: a meta-analysis with subgroup analysis for different levels of treatment response to antidepressants

RESULTS

We performed random effects meta-analysis We computed a weighted effect size (Hedges' g) for the difference of the absolute scores of the Hamilton Depression Rating Scale between the group given zinc and the group given placebo after 6 and after 12 weeks. We performed subgroup analysis according to whether not it was stated in the original studies that patients in a clinical trial or subgroup within a trial had not reached remission with previous treatment with a standard antidepressant during the same illness episode. After 6 weeks, we obtained the following effect sizes: Overall effect size: Hedges' g = -0.67, p = 0.03. Subgroup with documented non-remission: Hedges' g = - 0.97, p = 0.001. Group without documented non-remission -0.35, p = 0.24. After 12 weeks: Overall effect size: Hedges' g = -1.0, p = 0.03. Subgroup with documented non-remission: Hedges' g = - 1.46, p < 0.001. Group without documented non-remission: Hedges' g = - 0.54, p = 0.07.

CONCLUSIONS

We provide preliminary evidence for the efficacy of zinc vs. placebo as an adjunct to antidepressant medication.

Nutrition and behavioral health disorders: depression and anxiety

Suboptimal nutrition has been implicated in the underlying pathology of behavioral health disorders and may impede treatment and recovery. Thus, optimizing nutritional status should be a treatment for these disorders and is likely important for prevention. The purpose of this narrative review is to describe the global burden and features of depression and anxiety, and summarize recent evidence regarding the role of diet and nutrition in the prevention and management of depression and anxiety. Current evidence suggests that healthy eating patterns that meet food-based dietary recommendations and nutrient requirements may assist in the prevention and treatment of depression and anxiety. Randomized controlled trials are needed to better understand how diet and nutrition-related biological mechanisms affect behavioral health disorders, to assist with the development of effective evidence-based nutrition interventions, to reduce the impact of these disorders, and promote well-being for affected individuals.

Association between Fruit and Vegetable Consumption and Depression Symptoms in Young People and Adults Aged 15-45: A Systematic Review of Cohort Studies

Higher consumption of fruit and vegetables has been associated with a lower risk of various chronic diseases including coronary heart disease, obesity, and certain cancers. Recently, fruit and vegetable intake has also been linked with mental health, including depression; however, this area is largely unexplored studies in young people and adults. This systematic review aimed to evaluate the association between fruit and vegetable intake and depressive symptoms in young people and adults aged 15-45. The review used a predefined protocol registered with International Prospective Register of Systematic Reviews (PROSPERO) database (ID no: CRD42018091642). The systematic review focused on peer-reviewed cohort studies published from 1 January 2000 to 31 August 2020 using searches of six electronic databases. The exposure was fruit and vegetable consumption analysed both separately and/or together, and the outcome was depression or depressive symptoms. Data from eligible studies were extracted according to predefined criteria and the studies were appraised using the Newcastle-Ottawa Scale (NOS) for cohort studies to evaluate for study quality and risk of bias. A total of 12 studies from seven countries were deemed eligible and included in the qualitative synthesis, one study was categorised as "very good" quality, nine studies were "good" quality, and two studies were "moderate" quality by the quality assessment based on the total score for the NOS. The majority of cohort studies support the evidence that fruit consumption is associated with decreased risk of developing depression. However, the inconsistent results were observed when the effects of vegetable consumption were analysed independently, and the effects of fruit and vegetables combined were analysed. Despite this, the evidence seems to be building that a possible association exists, and this may have implications for addressing the burden of mental illness in young people and adults aged 15-45 years. More well-designed prospective cohort studies are needed to provide more robust evidence on the relationship between fruit and vegetable intake and depression.

Interaction of Serum Copper and Neurometabolites on Executive Dysfunction in Unmedicated Patients With Major Depressive Disorder

Objective: The mechanism of executive function (EF) impairment in major depressive disorder (MDD) remains unclear. Previous studies have demonstrated that altered serum copper levels and neurometabolic alterations may be associated with the psychopathology and cognitive impairment of MDD. While, their inter-relationships in MDD remain uncertain. The present study aims to assess whether the interaction between serum copper levels and neurometabolic alterations is involved in the deficit of executive function (EF) in patients with unmedicated MDD. Methods: Serum copper levels and EFs were measured in 41 MDD patients and 50 control subjects. EFs were evaluated by Trail Making Test, Part-B (TMT-B), Digit Symbol Substitution Test (DSST), Wisconsin Card Sorting Task (WCST), and Semantic Verbal Fluency testing (SVFT). Additionally, 41 patients and 41 healthy controls underwent proton magnetic resonance spectroscopy (¹H-MRS) to obtain ratios of N-acetyl aspartate to creatine (NAA/Cr) and choline-containing compounds to creatine (Cho/Cr) in the lenticular nucleus (LN) of basal ganglia (BG). Finally, association and interaction analysis were conducted to investigate their inter-relationships. Results: The results showed that patients performed worse in the DSST, WCST, TMT-B time and SVFT. Moreover, patients had higher serum copper levels, but lower NAA/Cr ratios in left LN of BG than healthy controls. In patients, serum copper levels were found to significantly negative associated with Categories Completed (CC) number of WCST (r = -0.408, p = 0.008), and positive associated with the Total Errors (TE) and Nonperseverative Errors (PE) number of WCST (r = 0.356, p = 0.023; r = -0.356, p = 0.022). In addition, the NAA/Cr ratios of left LN were found to significantly negative associated with VFS (r = -0.401, p = 0.009), as well as negative associated with serum copper levels (r = -0.365, p = 0.019). Finally, the interaction between copper and NAA may as influencing factors for SVFT and CC number of WCST in patients. Conclusion: Our results indicated that the interaction of abnormal copper levels and NAA/Cr neurometabolic disruption of the LN may impact executive dysfunction, and this may relevant to the pathophysiology of executive impairment in MDD patients.

Copper Concentrations in Ketamine Therapy for Treatment-Resistant Depression

Changes in serum copper concentration are observed in patients with depressive symptoms. Unmet needs in contemporary antidepressant treatment have increased interest in non-monoaminergic antidepressants, such as ketamine, an anaesthetic drug that has demonstrated a rapid antidepressant effect in patients with treatment-resistant depression (TRD). The purpose of this study was to examine whether serum copper concentrations change during ketamine treatment and whether there is an association between the copper concentrations and treatment response measured using psychometric scale scores. Moreover, the interlink between somatic comorbidities and copper concentration was studied. Patients with major depressive disorder or bipolar disorder were rated weekly by a clinician using the Montgomery-Asberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS). Copper level assessments were carried out weekly before the start of ketamine treatment and then after every second infusion and one week after the last ketamine infusion. The serum concentration of copper before ketamine treatment was significantly higher than that after the fifth infusion (p = 0.016), and the serum concentration after the treatment was significantly higher than that after the fifth infusion (p = 0.048). No significant correlations between changes in the copper serum concentrations and MADRS or YMRS were found. The serum copper level was not associated with somatic comorbidities during the course of treatment. This study provides data on the role of copper in short-term intravenous ketamine treatment in TRD, although no clear evidence of a connection between the copper level and treatment response was found.

Zinc: Roles in pancreatic physiology and disease

Zinc is an essential trace element. Deficiencies are frequently seen with gastrointestinal diseases, including chronic pancreatitis, nutritional deficiency, and reduced intestinal absorption. Additionally, reduced zinc levels have been linked to cellular changes associated with acute pancreatitis such as enhanced inflammation with increased macrophage activation and production of inflammatory cytokines such as IL-1β, impaired autophagy, and modulation of calcium homeostasis. Preliminary data suggest that zinc deficiency may lead to pancreatic injury in animal models. The purpose of this review is to explore the biologic effects of zinc deficiency that could impact pancreatic disease. MESH KEYWORDS: Malnutrition, inflammation, trace element.

Copper and anti-anhedonic effect of ketamine in treatment-resistant depression

Treatment-resistant depression (TRD) remains one of the major psychiatric challenges worldwide. Search for non-monoaminergic agents, possibly effective in treatment of TRD is of prime importance. One of those agents is ketamine - a dissociative, anesthetic drug exhibiting a fast antidepressant action in patients with TRD. Concurrently, anhedonia appears to be significant symptom domain with far-reaching impact on course of treatment. There is data demonstrating that abnormal copper levels might be associated with symptoms of depression. As there is common denominator in ketamine and copper role in neurotransmission this paper is to explore the associations of blood copper levels and psychometric measures in patients with TRD in course of major depressive disorder (MDD) and bipolar disorder (BP), focusing on anhedonia measured with Snaith-Hamilton Pleasure Scale (SHAPS) score.

Imipramine Influences Body Distribution of Supplemental Zinc Which May Enhance Antidepressant Action

Zinc (Zn) was found to enhance the antidepressant efficacy of imipramine (IMI) in human depression and animal tests/models of depression. However, the underlying mechanism for this effect remains unknown. We measured the effect of intragastric (p.o.) combined administration of IMI (60 mg/kg) and Zn (40 mg Zn/kg) in the forced swim test (FST) in mice. The effect of Zn + IMI on serum, brain, and intestinal Zn concentrations; Zn transporter (ZnT, ZIP) protein levels in the intestine and ZnT in the brain; including BDNF (brain-derived neurotrophic factor) and CREB (cAMP response element-binding protein) protein levels in the brain were evaluated. Finally, the effect of IMI on Zn permeability was measured in vitro in colon epithelial Caco-2 cells. The co-administration of IMI and Zn induced antidepressant-like activity in the FST in mice compared to controls and Zn or IMI given alone. This effect correlated with increased BDNF and the ratio of pCREB/CREB protein levels in the prefrontal cortex (PFC) compared to the control group. Zn + IMI co-treatment increased Zn concentrations in the serum and brain compared to the control group. However, in serum, co-administration of IMI and Zn decreased Zn concentration compared to Zn alone treatment. Also, there was a reduction in the Zn-induced enhancement of ZnT1 protein level in the small intestine. Zn + IMI also induced an increase in the ZnT4 protein level in the PFC compared to the control group and normalized the Zn-induced decrease in the ZnT1 protein level in the hippocampus (Hp). The in vitro studies revealed enhanced Zn permeability (observed as the increased transfer of Zn through the intestinal cell membrane) after IMI treatment. Our data indicate that IMI enhances Zn transfer through the intestinal tract and influences the redistribution of Zn between the blood and brain. These mechanisms might explain the enhanced antidepressant efficacy of combined IMI/Zn treatment observed in the FST in mice.

Serum copper and zinc levels correlate with biochemical metabolite ratios in the prefrontal cortex and lentiform nucleus of patients with major depressive disorder

BACKGROUND

Previous studies have demonstrated that copper and zinc metabolism are associated with the development of major depressive disorder (MDD). Abnormal copper and zinc levels may be related to neurotransmission and biochemical metabolism in the brains of MDD patients, especially in the prefrontal cortex (PFC) and lentiform nucleus (LN). However, the mechanism of how copper and zinc levels contribute to neural metabolism in MDD patients remains to be deciphered. This study aimed to correlate copper and zinc levels with biochemical metabolite ratios in the PFC and LN of MDD patients.

METHOD

Twenty-nine MDD patients and thirty-two healthy control (HC) volunteers were enrolled in this study. Proton magnetic resonance spectroscopy (¹H-MRS) was used to determine the levels of the N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) in the brain, and specifically in the PFC and LN regions. Serum copper and zinc levels were measured using atomic emission spectrometry (AES). Afterwards, copper and zinc levels were correlated with biochemical metabolite ratios in the PFC and LN regions of the brain.

RESULTS

Higher serum copper and lower serum zinc levels with higher copper/zinc ratios were observed in MDD patients. NAA/Cr ratios in the PFC of MDD patients were lower compared to HC volunteers. In MDD patients, serum copper levels were negatively correlated with NAA/Cr ratios in the right PFC and right LN, while copper/zinc ratios were negatively correlated with NAA/Cr ratios in the right LN. No significant differences in serum copper and zinc levels with NAA/Cr ratios in the left PFC and left LN were observed in MDD patients.

CONCLUSION

Our findings suggest that higher serum copper and lower serum zinc levels may contribute to neuronal impairment by affecting neuronal biochemical metabolite ratios in the right PFC and right LN of MDD patients. Abnormal copper and zinc levels may play an important role in the pathophysiology of MDD.

Lowered zinc and copper levels in drug-naïve patients with major depression: Effects of antidepressants, ketoprofen and immune activation

Objectives: The aim of the present work is to examine the effects of treatment with sertraline with and without ketoprofen on serum levels of zinc and copper in association with immune-inflammatory biomarkers in drug-naïve major depressed patients.Methods: We measured serum zinc and copper, interleukin (IL)-1β, IL-4, IL-6, IL-18, interferon-γ, and transforming growth factor-β1 in 40 controls and 133 depressed patients. The clinical efficacy of the treatment was measured using the Beck Depression Inventory-II (BDI-II) at baseline and 8 weeks later.Results: We found significantly reduced serum zinc and copper in association with upregulation of all cytokines, indicating activation of the immune-inflammatory responses system (IRS) and the compensatory immune regulatory system (CIRS). Treatment with sertraline significantly increased zinc and decreased copper. During treatment, there was a significant inverse association between serum zinc and immune activation. The improvement in the BDI-II during treatment was significantly associated with increments in serum zinc coupled with attenuation of the IRS/CIRS.Conclusions: Lower zinc is a hallmark of depression, while increments in serum zinc and attenuation of the immune-inflammatory response during treatment appear to play a role in the clinical efficacy of sertraline.

Polaprezinc (Zinc-L-Carnosine Complex) as an Add-on Therapy for Binge Eating Disorder and Bulimia Nervosa, and the Possible Involvement of Zinc Deficiency in These Conditions: A Pilot Study

BACKGROUND

Zinc plays an important role in appetite regulation. L-Carnosine, an endogenous dipeptide, may also regulate eating behavior via its histaminergic and antiglutamatergic properties. Polaprezinc (zinc-L-carnosine complex) is a medication for gastric ulcers. A small case series reported successful treatment of binge eating with add-on polaprezinc.

METHODS

This was an open trial of add-on polaprezinc in patients with binge eating disorder (BED; n = 22) or bulimia nervosa (BN; n = 7) receiving antidepressants. A 4-week baseline period was followed by a 16-week polaprezinc treatment at 150 mg/d (containing 34 mg zinc and 116 mg L-carnosine) in addition to ongoing psychotropic medications. We also assessed their zinc status via a laboratory index and zinc deficiency-related symptoms.

RESULTS

At the study end, both conditions showed a significant reduction in the 4-week frequency of combined objective and subjective binge eating episodes, the 4-week frequency of days when at least 1 such episode occurred (only in BED), several aspects of eating disorder psychopathology (rated by the Eating Disorder Examination-Questionnaire), and comorbid depressive symptoms (rated by the 16-item Quick Inventory of Depressive Symptomatology [Self-Report]). Serum copper/zinc ratio decreased from 1.4 to 1.1 on average in both conditions. All patients had multiple zinc deficiency-related symptoms at baseline that substantially improved after polaprezinc treatment. Overall, the effectiveness of polaprezinc was greater in BED patients than in BN patients, with minor adverse effects.

CONCLUSIONS

These findings offer preliminary evidence for the effectiveness of polaprezinc in treating BED and BN and suggest the involvement of zinc deficiency in these conditions.

DNA damage and repair in neuropsychiatric disorders. What do we know and what are the future perspectives?

Over the past two decades, extensive research has been done to elucidate the molecular etiology and pathophysiology of neuropsychiatric disorders. In majority of them, including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), bipolar disorder (BD), schizophrenia and major depressive disorder, increased oxidative and nitrosative stress was found. This stress is known to induce oxidative damage to biomolecules, including DNA. Accordingly, increased mitochondrial and nuclear DNA, as well as RNA damage, were observed in patients suffering from these diseases. However, recent findings indicate that the patients are characterised by impaired DNA repair pathways, which may suggest that these DNA lesions could be also a result of their insufficient repair. In the current systematic, critical review, we aim to sum up, using available literature, the knowledge about the involvement of nuclear and mitochondrial DNA damage and repair, as well as about damage to RNA in pathoetiology of neuropsychiatric disorders, i.e., AD, PD, ALS, BD, schizophrenia and major depressive disorder, as well as the usefulness of the discussed factors as being diagnostic markers and targets for new therapies. Moreover, we also underline the new directions to which future studies should head to elucidate these phenomena.

Rapid antidepressant actions of imipramine potentiated by zinc through PKA-dependented regulation of mTOR and CREB signaling

The slow onset of traditional antidepressants has become an urgent clinical issue, researchers are constantly exploring new antidepressants with prompt action. Previous studies have found that zinc levels were decreased in serum and brain of depressed patients or animal models. Zinc treatment can improve depressive symptoms and enhance the antidepressant effects of monoamine antidepressants. However, its mechanism of action is still unclear. This present study aims to investigate whether the zinc can enhance the rapid action of traditional antidepressant imipramine and to explore the potential mechanisms of action through the rapid antidepressant targets CREB (cAMP-response element binding protein) and mTOR (mammalian target of the rapamycin). Drug treatment included intraperitoneal injection of imipramine or zinc alone and imipramine plus zinc. Zinc had a rapid enhanced antidepressive effect on the imipramine and achieved a rapid antidepressant effect similar to ketamine. Combination of zinc with imipramine rapidly enhanced the phosphorylation of mTOR Ser2448 and CREB Ser133, and increased the expression of mTOR and CREB, which were dependent on the activation of PKA. In conclusion, combination therapy with zinc and monoamine antidepressants may overcome the problem of slow-onset action of traditional antidepressants in clinical uses.

The Combined Effects of Cr(III) Supplementation and Iron Deficiency on the Copper and Zinc Status in Wistar Rats

The aim of the study was to assess the combined effects of chromium(III) supplementation and iron deficiency on the copper (Cu) and zinc (Zn) status in female rats. The Cr, Fe, Cu and Zn dietary and tissular levels were measured by Atomic Absorption Spectrometry (AAS) method. The data show that chromium(III) supplementation compensated for the negative effects of Fe deficiency on the Cu content but it deepened the effect on Zn levels in the female rats. Detailed data on the status of trace elements and their interactions in healthy subjects and patients with metabolic disorders (e.g. anaemia, diabetes mellitus) are strongly required for effective nutritional and therapeutic strategies.

Zinc improves clomipramine effects on depressive and locomotor behavior and reverses its oxidative stress in rats

Depression is a common mental disease affecting a lot of people of all ages around the world. Today, improving the therapeutic effects of currently used antidepressants such as clomipramine and, especially when they are administered at high doses is a topic of interest. The study aims to evaluate the eventual role of zinc (30 mg/Kg) in ameliorating clomipramine (75 mg/Kg) effects on behavior and oxidative stress equilibrium following a 6 day treatment in male Wistar rats. Our main findings showed that zinc improved clomipramine antidepressant and locomotor effects. Moreover, zinc reversed the oxidative stress induced by this drug in the liver. Thus, zinc at 30 mg/Kg may constitute an efficient adjuvant for clomipramine used at a high dose (75 mg/Kg) by boosting its efficacy on behavior and alleviating its negative effects on oxidative balance in liver.

Antidepressant-like activity of hyperforin and changes in BDNF and zinc levels in mice exposed to chronic unpredictable mild stress

Chronic unpredictable mild stress (CUMS) - a rodent model of depression mimics a variety of neurochemical and behavioral alterations similar to those seen in human depression. This study evaluated the antidepressant activity of hyperforin in the CUMS model using fluoxetine (FLX) as a reference drug. The antidepressant-like effects of hyperforin and FLX were evaluated in the tail suspension test (TST), forced swim test (FST), and splash test (SPT). CUMS induced an increase in immobility time in mice (pro-depressive effects) in the FST and TST. CUMS-induced changes were reversed by chronic treatment with hyperforin (2.5 and 5 mg/kg), as well as FLX (10 mg/kg). SPT results revealed a decrease in the frequency and duration of grooming in stressed mice. These effects were normalized by hyperforin (5 mg/kg) and FLX treatment. Hyperforin (2.5 mg/kg) only reversed the CUMS-induced deficits related to the frequency of grooming. CUMS also caused a decrease in zinc concentration in the frontal cortex (FC) and hippocampus (Hp) of mice; hyperforin (2.5 mg/kg) increased zinc concentration in the Hp of control rats. CUMS also induced a decrease in BDNF protein levels in the FC and Hp, while decreasing the pCREB/CREB ratio only in the Hp. Hyperforin (2.5 and 5 mg/kg) reversed the CUMS-induced reduction of BDNF only in the Hp. Our results demonstrate the antidepressant-like activity of hyperforin in the CUMS model in mice and the possible involvement of hippocampal BDNF/zinc alterations in this activity.

Zinc signaling and epilepsy

Evidence from both preclinical and clinical studies suggest the importance of zinc homeostasis in seizures/epilepsy. Undoubtedly, zinc, via modulation of a variety of targets, is necessary for maintaining the balance between neuronal excitation and inhibition, while an imbalance between excitation and inhibition underlies seizures. However, the relationship between zinc signaling and seizures/epilepsy is complex as both extracellular and intracellular zinc may produce either protective or detrimental effects. This review provides an overview of preclinical/behavioral, functional and molecular studies, as well as clinical data on the involvement of zinc in the pathophysiology and treatment of seizures/epilepsy. Furthermore, the potential of targeting elements associated with zinc signaling or homeostasis and zinc levels as a therapeutic strategy for epilepsy is discussed.

In major affective disorders, early life trauma predict increased nitro-oxidative stress, lipid peroxidation and protein oxidation and recurrence of major affective disorders, suicidal behaviors and a lowered quality of life

Early life trauma (ELT) may increase the risk towards bipolar disorder (BD) and major depression (MDD), disorders associated with activated neuro-oxidative and neuro-nitrosative stress (O&NS) pathways. It has remained elusive whether ELTs are associated with O&NS and which ELTs are associated with distinct affective disorder phenotypes. This case-control study examined patients with BD (n = 68) and MDD (n = 37) and healthy controls (n = 66). The Child Trauma Questionnaire (CTQ) was used to assess specific ELT. We measured malondialdehyde (MDA), lipid hydroperoxides (LOOH), superoxide dismutase (SOD), catalase, advanced oxidation protein products (AOPP); NO metabolites (NOx), paraoxonase 1 activity, zinc, albumin, high density lipoprotein cholesterol and -SH groups and computed z-unit weighted composite scores. Physical neglect significantly predicts higher z-unit weighted composite scores of LOOH+SOD, LOOH+SOD+NOx, LOOH+SOD+NOx + MDA and LOOH+SOD+NOx + AOPP. Sexual abuse was associated with a significantly lower composite score of zinc+albumin+SH. Emotional abuse was associated with severity of depression and anxiety, number of depressive and manic episodes, alcohol and hypnotics use, lifetime suicidal behavior and lowered quality of life. Sexual abuse was associated with an increased risk towards BD, but not MDD. ELT, especially physical neglect, may drive increased (nitro-)oxidative stress coupled with lipid and protein oxidation, which - together with emotional abuse - may play a role in severity of illness, lowered quality of life and MDD. ELTs are also associated with the onset of BD, but this link did not appear to be related to activated O&NS pathways. These novel findings deserve confirmation in prospective studies.

Role of copper in depression. Relationship with ketamine treatment

Depression is one of the most common psychiatric issues with a proportion of adults with major depressive disorder who fail to achieve remission with index pharmacological treatment. There are unmet needs in ADT focus on non-monoaminergic agents. Accumulating evidence suggests that the N-Methyl-d-aspartate receptor (NMDAR) plays an important role in the neurobiology and treatment of major depressive disorder. The role of copper ions in pathogenesis and treatment of depression is not fully clarified, however interaction between copper and NMDAR is of prime importance. Release of copper ions inhibits NMDAR and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor function thus protects neurons from glutamatergic excitotoxity. Abnormalities in glutamatergic transmission are the key of glutamate hypothesis of depression. Some authors revealed that NMDARs are also regulated by cellular prion protein (PrP^C) and indicated that interactions of copper, glycine and NMDARs subunits are vital for the regulation of the receptor. As NMDAR antagonist ketamine is known to produce rapid antidepressive effect, observation of copper serum levels in patients treated with ketamine may provide important information about connections between NMDAR antagonistic agents and trace elements antagonistic to that receptor. It is necessary to carry out further studies related to copper and ketamine in depression treatment.

Zinc in schizophrenia: A meta-analysis

OBJECTIVE

The role of zinc homeostasis in various psychopathologies is an emerging area of interest. Zinc is strongly implicated in depressive disorders but is inadequately studied in schizophrenia, despite growing evidence of abnormal zinc transporters associated with schizophrenia. A meta-analysis of serum zinc concentrations in persons with schizophrenia was conducted to address this gap.

METHOD

PubMed and Embase were searched for all articles published through February 2018 that reported serum zinc concentrations in individuals with schizophrenia and in comparison subjects. A random-effects meta-analysis was carried out to compare mean serum zinc concentrations between the groups in terms of the weighted mean difference.

RESULTS

The current meta-analysis combined 10 studies, including a total of 658 schizophrenia patients and 1008 controls. Serum zinc concentration was significantly lower in individuals with schizophrenia than controls (12.81 μg/dl (1.96 μmol/l), t = -2.59, 95% CI: -22.50 to -3.12, p < 0.05). The reduction in zinc levels was more pronounced among inpatients and newly diagnosed, drug-naïve patients.

CONCLUSIONS

The current meta-analysis supports a disturbance of zinc homeostasis in individuals with schizophrenia compared to healthy controls, although the relationship between reduced serum zinc levels and psychotic symptoms remains unknown. Altered serum zinc might be linked to defective transporters and/or inflammation that impact the brain's glutamatergic system.

Serum zinc levels in acute psychiatric patients: A case series

Zinc dysregulation is linked to neuropsychiatric disorders and a beneficial response to zinc supplementation has been demonstrated for depression. In this case series, we examined serum zinc levels with respect to clinical factors among 20 acutely ill psychiatric cases admitted to a large urban public hospital. The results showed frank clinical zinc insufficiency in a quarter of the subjects. Group-wise analyses showed a significant association between reduced serum zinc and diagnosis of depression, and reduced serum zinc in those with aggressive, assaultive, or violent behaviors. By contrast, relatively elevated zinc levels were observed in a subset of psychotic cases on antipsychotics and mood stabilizers who had no mood symptoms. In summary, clinical zinc insufficiency was common in these acutely admitted psychiatric cases. Zinc supplementation may ameliorate symptoms in certain cases and should be considered in treatment planning. A separate patient group had elevated zinc levels, which could conceivably be pathogenic. Larger studies are needed to confirm and extend this pilot data.

The interplay between inflammation, oxidative stress, DNA damage, DNA repair and mitochondrial dysfunction in depression

A growing body of evidence suggests that inflammation, mitochondrial dysfunction and oxidant-antioxidant imbalance may play a significant role in the development and progression of depression. Elevated levels of reactive oxygen and nitrogen species - a result of oxidant-antioxidant imbalance - may lead to increased damage of biomolecules, including DNA. This was confirmed in depressed patients in a research study conducted by our team and other scientists. 8-oxoguanine - a marker of oxidative DNA damage - was found in the patients' lymphocytes, urine and serum. These results were confirmed using a comet assay on lymphocytes. Furthermore, it was shown that the patients' cells repaired peroxide-induced DNA damage less efficiently than controls' cells and that some single nucleotide polymorphisms (SNP) of the genes involved in oxidative DNA damage repair may modulate the risk of depression. Lastly, less efficient DNA damage repair observed in the patients can be, at least partly, attributed to the presence of specific SNP variants, as it was revealed through a genotype-phenotype analysis. In conclusion, the available literature shows that both oxidative stress and less efficient DNA damage repair may lead to increased DNA damage in depressed patients. A similar mechanism may result in mitochondrial dysfunction, which is observed in depression.

The Emerging Role for Zinc in Depression and Psychosis

Zinc participation is essential for all physiological systems, including neural functioning, where it participates in a myriad of cellular processes. Converging clinical, molecular, and genetic discoveries illuminate key roles for zinc homeostasis in association with clinical depression and psychosis which are not yet well appreciated at the clinical interface. Intracellular deficiency may arise from low circulating zinc levels due to dietary insufficiency, or impaired absorption from aging or medical conditions, including alcoholism. A host of medications commonly administered to psychiatric patients, including anticonvulsants, oral medications for diabetes, hormones, antacids, anti-inflammatories and others also impact zinc absorption. Furthermore, inefficient genetic variants in zinc transporter molecules that transport the ion across cellular membranes impede its action even when circulating zinc concentrations is in the normal range. Well powered clinical studies have shown beneficial effects of supplemental zinc in depression and it important to pursue research using zinc as a potential therapeutic option for psychosis as well. Meta-analyses support the adjunctive use of zinc in major depression and a single study now supports zinc for psychotic symptoms. This manuscript reviews the biochemistry and bench top evidence on putative molecular mechanisms of zinc as a psychiatric treatment.

Allosteric Inhibition of Serotonin 5-HT7 Receptors by Zinc Ions

The allosteric regulation of G protein-coupled receptors (GPCRs) is a well-known phenomenon, but there are only a few examples of allosteric modulation within the metabotropic serotonergic receptor family. Recently, we described zinc non-competitive interactions toward agonist binding at serotonin 5-HT_1A receptors, in which biphasic effects, involving potentiation at sub-micromolar concentrations (10 μM) and inhibition at sub-millimolar concentrations (500 μM) of Zn²⁺ in radioligand binding assays, were consistent with both the agonist and antagonist-like effects of zinc ions observed in in vivo studies. Here, we showed new data demonstrating zinc allosteric inhibition of both agonist and antagonist binding at human recombinant 5-HT₇ receptors stably expressed in HEK293 cells as observed by radioligand binding studies as well as zinc neutral antagonism displayed by the concentration of 10 μM in the functional LANCE assay. The allosteric nature of the effect of Zn on 5-HT₇ receptors was confirmed (1) in saturation studies in which zinc inhibited the binding of potent orthosteric 5-HT₇ receptor radioligands, the agonist [³H]5-CT, and the two antagonists [³H]SB-269970 and [³H]mesulergine, showing ceiling effect and differences in the magnitude of negative cooperativity (α = 0.15, 0.06, and 0.25, respectively); (2) in competition experiments in which 500 μM of zinc inhibited all radioligand displacements by non-labeled orthosteric ligands (5-CT, SB-269970, and clozapine), and the most significant reduction in affinity was observed for the 5-CT agonist (4.9–16.7-fold) compared with both antagonists (1.4–3.9-fold); and (3) in kinetic experiments in which 500 μM zinc increased the dissociation rate constants for [³H]5-CT and [³H]mesulergine but not for [³H]SB-269970. Additionally, in the functional LANCE test using the constitutively active HEK293 cell line expressing the 5-HT₇ receptor, 10 μM zinc had features of neutral antagonism and increased the EC₅₀ value of the 5-CT agonist by a factor of 3.2. Overall, these results showed that zinc can act as a negative allosteric inhibitor of 5-HT₇ receptors. Given that the inhibiting effects of low concentrations of zinc in the functional assay represent the most likely direction of zinc activity under physiological conditions, among numerous zinc-regulated proteins, the 5-HT₇ receptor can be considered a serotonergic target for zinc modulation in the CNS.

Zinc in the Monoaminergic Theory of Depression: Its Relationship to Neural Plasticity

Preclinical and clinical studies have demonstrated that zinc possesses antidepressant properties and that it may augment the therapy with conventional, that is, monoamine-based, antidepressants. In this review we aim to discuss the role of zinc in the pathophysiology and treatment of depression with regard to the monoamine hypothesis of the disease. Particular attention will be paid to the recently described zinc-sensing GPR39 receptor as well as aspects of zinc deficiency. Furthermore, an attempt will be made to give a possible explanation of the mechanisms by which zinc interacts with the monoamine system in the context of depression and neural plasticity.

The serum zinc concentration as a potential biological marker in patients with major depressive disorder

Despite many clinical trials assessing the role of zinc in major depressive disorder (MDD), the conclusions still remain ambiguous. The aim of the present clinical study was to determine and comparison the zinc concentration in the blood of MDD patients (active stage or remission) and healthy volunteers (controls), as well as to discuss its potential clinical usefulness as a biomarker of the disease. In this study 69 patients with current depressive episode, 45 patients in remission and 50 controls were enrolled. The zinc concentration was measured by electrothermal atomic absorption spectrometry (ET AAS). The obtained results revealed, that the zinc concentration in depressed phase were statistically lower than in the healthy volunteers [0.89 vs. 1.06 mg/L, respectively], while the zinc level in patients achieve remission was not significantly different from the controls [1.07 vs. 1.06 mg/L, respectively]. Additionally, among the patients achieve remission a significant differences in zinc concentration between group with and without presence of drug-resistance in the previous episode of depression were observed. Also, patients in remission demonstrated correlation between zinc level and the average number of depressive episodes in the last year. Serum zinc concentration was not dependent on atypical features of depression, presence of psychotic symptoms or melancholic syndrome, age, age of onset or duration of disease, number of episodes in the life time, duration of the episode/remission and severity of depression measured by the Hamilton Rating Scale for Depression (HDRS), and the Montgomery-Asberg Depression Rating Scale (MADRS). Concluding, our findings confirm the correlation between zinc deficit present in the depressive episode, and are consistent with the majority of previous studies. These results may also indicate that serum zinc concentration might be considered as a potential biological marker of MDD.

Antidepressant activity of zinc: Further evidence for the involvement of the serotonergic system

BACKGROUND

The present study sought to further evaluate the role of the serotonergic system especially the postsynaptic 5-HT1A receptors (5-HT1AR) in the mechanism of antidepressant action of zinc.

METHODS

Messenger RNA (mRNA), protein level, and 5-HT1AR density as well as the rate of monoamine (dopamine, DA, and serotonin) metabolism in the prefrontal cortex (PFC) and hippocampus (Hp) of rats subjected to acute and chronic (21days) zinc (5mg Zn/kg) treatment were measured.

RESULTS

Acute or chronic zinc treatment did not induce any changes in 5-HT1AR mRNA levels in the PFC or Hp of rats. However, chronic zinc treatment induced increases in both 5-HT1AR protein levels and density of 5-HT1A receptor binding sites in the Hp of rats. Chronic zinc treatment also increased tissue levels of serotonin metabolite and turnover in the rat Hp. On the other hand, DA, DOPAC, HVA tissue levels increased while DOPAC/DA and 3MT/DA decreased in the PFC of rats after chronic zinc treatment. Acute treatment induced increases only in tissue levels of DOPAC, and DOPAC/DA.

CONCLUSIONS

Our results confirm that the antidepressant effects of zinc are mediated in concert with the modulation of the serotonergic system including postsynaptic 5-HT1ARs and allude to a possible involvement of dopaminergic neurotransmission in this action.

The level of the zinc homeostasis regulating proteins in the brain of rats subjected to olfactory bulbectomy model of depression

BACKGROUND

Zinc transporters (ZnTs) and metallothioneins (MT) are important in maintaining Zn homeostasis in the brain. The present study was designed to find out whether alterations in ZnTs and MTs are associated with the pathophysiology of depression and the mechanism of antidepressant action.

METHODS

Messenger RNA and proteins of ZnT1, ZnT3, ZnT4, ZnT5, ZnT6 and MT1/2 were measured in the prefrontal cortex (PFC) and hippocampus (Hp) of rats subjected to olfactory bulbectomy (OB) (a model of depression) and chronic amitriptyline (AMI) treatment by Real Time PCR and Western Blot/Immunohistochemistry (IHP).

RESULTS

Results in the OB rats showed: increases in the protein levels of ZnT1 in the PFC and Hp and MT1/2 in the PFC; a decrease in ZnT3 protein level in the PFC; no changes in ZnT4, ZnT5 and ZnT6 in the PFC and Hp. IHP labeling revealed increases in the optical densities of ZnT1-IR in the PFC and Hp and decreases in ZnT3 and ZnT4-IR in the PFC of OB rats. Although OB had no effects on gene expression of ZnTs, mRNAs for MT1/2 were increased. Chronic AMI treatment did not influence protein levels of ZnTs and MT1/2 in Sham and OB rats; however decreased mRNA levels of ZnT4 and ZnT5 in PFC and ZnT1, ZnT3, ZnT4 and ZnT6 in Hp of Sham rats and normalized OB induced increase in MT1/2 gene expression.

CONCLUSIONS

Changes in ZnTs and MT1/2 suggest altered cortical distribution of Zn in the OB model which further supports the hypothesis that Zn dyshomeostasis may be involved in the pathophysiology of depression.

Concentration-Dependent Dual Mode of Zn Action at Serotonin 5-HT1A Receptors: In Vitro and In Vivo Studies

Recent data has indicated that Zn can modulate serotonergic function through the 5-HT1A receptor (5-HT1AR); however, the exact mechanisms are unknown. In the present studies, radioligand binding assays and behavioural approaches were used to characterize the pharmacological profile of Zn at 5-HT1ARs in more detail. The influence of Zn on agonist binding to 5-HT1ARs stably expressed in HEK293 cells was investigated by in vitro radioligand binding methods using the agonist [3H]-8-OH-DPAT. The in vivo effects of Zn were compared with those of 8-OH-DPAT in hypothermia, lower lip retraction (LLR), 5-HT behavioural syndrome and the forced swim (FST) tests. In the in vitro studies, biphasic effects, which involved allosteric potentiation of agonist binding at sub-micromolar Zn concentrations and inhibition at sub-millimolar Zn concentrations, were found. The in vivo studies showed that Zn did not induce LLR or elements of 5-HT behavioural syndrome but blocked such effects induced by 8-OH-DPAT. Zn decreased body temperature in rats and mice; however, Zn failed to induce hypothermia in the 5-HT1A autoreceptor knockout mice. In the FST, Zn potentiated the effect of 8-OH-DPAT. However, in the FST performed with the 5-HT1A autoreceptor knockout mice, the anti-immobility effect of Zn was partially blocked. Both the binding and behavioural studies suggest a concentration-dependent dual mechanism of Zn action at 5-HT1ARs, with potentiation at low dose and inhibition at high dose. Moreover, the in vivo studies indicate that Zn can modulate both presynaptic and postsynaptic 5-HT1ARs; however, Zn's effects at presynaptic receptors seem to be more potent.

Zinc transporters protein level in postmortem brain of depressed subjects and suicide victims

BACKGROUND

Major depressive disorder (MDD) is a serious psychiatric illness, associated with an increasing rate of suicide. The pathogenesis of depression may be associated with the disruption of zinc (Zn) homeostasis. In the brain, several proteins that regulate Zn homeostasis are present, including Zn transporters (ZnTs) which remove Zn from the cytosol. The present study was designed to investigate whether depression and suicide are associated with alterations in the expression of the ZnTs protein.

METHODS

Protein levels of ZnT1, ZnT3, ZnT4, ZnT5 and ZnT6 were measured in postmortem brain tissue from two different cohorts. Cohort A contained 10 subjects diagnosed with MDD (7 were suicide victims) and 10 psychiatrically-normal control subjects and cohort B contained 11 non-diagnosed suicide victims and 8 sudden-death control subjects. Moreover, in cohort A we measured protein level of NMDA (GluN2A subunit), AMPA (GluA1 subunit) and 5-HT1A receptors and PSD-95. Proteins were measured in the prefrontal cortex (PFC) using Western blotting. In addition, Zn concentration was measured using a voltammetric method.

RESULTS

There was a significant increase in protein levels of ZnT1, ZnT4, ZnT5 in the PFC in MDD, relative to control subjects, while ZnT3 protein level was decreased in MDD. There was no significant difference in the Zn concentration in the PFC between control and MDD subjects. Similarly, in the PFC of suicide victims (non-diagnosed), an increase in protein levels of ZnT1, ZnT4, ZnT5 and ZnT6 was observed. Conversely, protein levels of ZnT3 were decreased in both suicide victims and subjects with MDD, in comparison with control subjects. There was also a significant decrease in the protein level of GluA1, GluN2A, PSD-95 and 5-HT1A in MDD.

CONCLUSIONS

Our studies suggest that alterations in Zn transport proteins are associated with the pathophysiology of MDD and suicide.

Potential antidepressant-like properties of the TC G-1008, a GPR39 (zinc receptor) agonist

Some forms of depression appear to be more related to the glutamatergic system. G-coupled protein receptor 39 (GPR39) is the metabotropic zinc receptor, which may be involved in the pathophysiology of depression and in the antidepressant response. Its deficiency abolishes the antidepressant response, which means that GPR39 is required to obtain a therapeutic effect in depression. This raises the possibility that agonists of the zinc receptor may have a role in antidepressant treatment. To explore this possibility we investigated animal behaviour in the forced swim test, the tail suspension test (to assess antidepressant-like properties), the light/dark test and the elevated plus maze test (to assess anxiolytic-like properties), following acute administration of a GPR39 agonist (TC G-1008). We found an antidepressant response (as measured by the forced swim test but not by the tail suspension test) in mice following the GPR39 agonist treatment. Additionally, we observed the opposite results in the light/dark box (decreased overall distance; increased time spent in the lit compartment; decreased time spent in the dark compartment; increased freezing time) and elevated plus maze (no significant changes), which may be a consequence of the sedative effect of TC G-1008. We also found hippocampal GPR39 and brain-derived neurotrophic factor (BDNF) up-regulation following administration of the GPR39 agonist, which may be undiscovered so far as a possible novel agent in the treatment of mood disorders.

Oxidative Stress Implications in the Affective Disorders: Main Biomarkers, Animal Models Relevance, Genetic Perspectives, and Antioxidant Approaches

The correlation between the affective disorders and the almost ubiquitous pathological oxidative stress can be described in a multifactorial way, as an important mechanism of central nervous system impairment. Whether the obvious changes which occur in oxidative balance of the affective disorders are a part of the constitutive mechanism or a collateral effect yet remains as an interesting question. However it is now clear that oxidative stress is a component of these disorders, being characterized by different aspects in a disease-dependent manner. Still, there are a lot of controversies regarding the relevance of the oxidative stress status in most of the affective disorders and despite the fact that most of the studies are showing that the affective disorders development can be correlated to increased oxidative levels, there are various studies stating that oxidative stress is not linked with the mood changing tendencies. Thus, in this minireview we decided to describe the way in which oxidative stress is involved in the affective disorders development, by focusing on the main oxidative stress markers that could be used mechanistically and therapeutically in these deficiencies, the genetic perspectives, some antioxidant approaches, and the relevance of some animal models studies in this context.

Zinc and imipramine reverse the depression-like behavior in mice induced by chronic restraint stress

Depression is a common psychopathological disorders. Studies of depression have indicated that zinc play a role in the depression pathophysiology and treatment. In present study, we examined the effects of zinc and imipramine supplement alone or combination of zinc and imipramine in mice induced by chronic restraint stress (CRS). Moreover, the possible roles of zinc receptor (G protein-coupled receptor 39, GPR39)-related pathway was investigated. Decreased weight and increased corticosterone (CORT) were observed after 3 weeks CRS exposure. It was shown that CRS induced lower serum zinc, higher hippocampal zinc, increased immobility time in tail suspension test and decreased movement distance in spontaneous activity test, which could be normalized by zinc (30 mg/kg) and imipramine (20 mg/kg) supplement alone and combination of zinc (15 mg/kg) and imipramine (5 mg/kg) for 3 weeks after CRS exposure. Moreover, the changes in mRNA expressions of GPR39, cAMP-response element binding protein (CREB), brain-derived neurotropic factor (BDNF) and n-methytl-d-aspartate receptors (NMDAR) could be reversed by the same treatment mentioned above. These results suggested that zinc dyshomeostasis in serum and hippocampus and depression-like behavior in CRS exposure animals observed in present study could be normalized by zinc and imipramine. The combination of zinc and imipramine in low dose has synergetic effects. The possible mechanism might be correlated to GPR39 receptor-related pathway.

Lower Serum Zinc and Higher CRP Strongly Predict Prenatal Depression and Physio-somatic Symptoms, Which All Together Predict Postnatal Depressive Symptoms

Pregnancy and delivery are associated with activation of immune-inflammatory pathways which may prime parturients to develop postnatal depression. There are, however, few data on the associations between immune-inflammatory pathways and prenatal depression and physio-somatic symptoms. This study examined the associations between serum zinc, C-reactive protein (CRP), and haptoglobin at the end of term and prenatal physio-somatic symptoms (fatigue, back pain, muscle pain, dyspepsia, obstipation) and prenatal and postnatal depressive and anxiety symptoms as measured using the Edinburgh Postnatal Depression Scale (EPDS), Beck Depression Inventory (BDI), Hamilton Depression Rating Scale (HAMD), and Spielberger's State Anxiety Inventory (STAI). Zinc and haptoglobin were significantly lower and CRP increased at the end of term as compared with non-pregnant women. Prenatal depression was predicted by lower zinc and lifetime history of depression, anxiety, and premenstrual tension syndrome (PMS). The latter histories were also significantly and inversely related to lower zinc. The severity of prenatal EDPS, HAMD, BDI, STAI, and physio-somatic symptoms was predicted by fatigue in the first and second trimesters, a positive life history of depression, anxiety, and PMS, and lower zinc and higher CRP. Postnatal depressive symptoms are predicted by prenatal depression, physio-somatic symptoms, zinc and CRP. Prenatal depressive and physio-somatic symptoms have an immune-inflammatory pathophysiology, while postnatal depressive symptoms are highly predicted by prenatal immune activation, prenatal depression, and a lifetime history of depression and PMS. Previous episodes of depression, anxiety disorders, and PMS may prime pregnant females to develop prenatal and postnatal depressive symptoms via activated immune pathways.

The role of oxidative and nitrosative stress in accelerated aging and major depressive disorder

Major depressive disorder (MDD) affects millions of individuals and is highly comorbid with many age associated diseases such as diabetes mellitus, immune-inflammatory dysregulation and cardiovascular diseases. Oxidative/nitrosative stress plays a fundamental role in aging, as well as in the pathogenesis of neurodegenerative/neuropsychiatric disorders including MDD. In this review, we critically review the evidence for an involvement of oxidative/nitrosative stress in acceleration of aging process in MDD. There are evidence of the association between MDD and changes in molecular mechanisms involved in aging. There is a significant association between telomere length, enzymatic antioxidant activities (SOD, CAT, GPx), glutathione (GSH), lipid peroxidation (MDA), nuclear factor κB, inflammatory cytokines with MDD. Major depression also is characterized by significantly lower concentration of antioxidants (zinc, coenzyme Q10, PON1). Since, aging and MDD share a common biological base in their pathophysiology, the potential therapeutic use of antioxidants and anti-aging molecules in MDD could be promising.

Decreased serum zinc concentration during depressive episode in patients with bipolar disorder

OBJECTIVES

Zinc may be involved in the pathophysiology and treatment of depressive disorder. However, data on this issue in bipolar disorder (BD) are limited. The aim of the study was to assess zinc concentrations in the blood serum of patients at various phases and stages of bipolar disorder.

METHODS

The study included 129 patients with a diagnosis of bipolar disorder type I (n=69) or type II (n=60). Fifty-eight were in a depressive episode, 23 in a manic episode and 48 in remission. Fifty healthy volunteers made a control group. Zinc concentration was measured using flame atomic absorption spectrometry.

RESULTS

Serum zinc level in patients diagnosed with BD type I in the depressive phase was significantly reduced as compared with mania, remission and healthy subjects. In the BD type II, serum zinc level in hypomania, depression or remission phase was not significantly different from the control group. In the whole group, lower level of zinc in depression compared to remission and control subjects was found during late stage of the illness but not in the early stage. Zinc concentration was not dependent on the severity of manic or depressive symptoms and subtype of depression but correlated positively with the number of manic/hypomanic relapses in the past year.

LIMITATIONS

Lack of prospective model, heterogeneity of pharmacological treatment, small number of subgroups presenting specified clinical features.

CONCLUSIONS

Decreased serum zinc concentration occurs in depression in BD type I and probably in depression in the late stage of BD.

Albumin and depression in elderly stroke survivors: An observational cohort study

BACKGROUND/OBJECTIVES

Post-stroke depression affects approximately one third of stroke survivors. In non-stroke affected populations, depressive symptomatology is associated with hypoalbuminemia. This is also common among stroke survivors and associated with poor outcome and increased mortality. The role of stroke-associated hypoalbuminemia in post-stroke depression is not clear. We aimed to explore the relationship between serum albumin and post-stroke depression, as measured 20 months post-stroke.

SUBJECTS/METHODS

Observational cohort study of elderly Swedish patients drawn from the 'Gothenburg 70+ Stroke Study' (n=149) and assessed at 20 months after stroke onset. Serum albumin was drawn from venous blood and analysed with gas chromatography/mass spectrometry. Depressive symptomatology was assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS) and functional impairment was assessed using the Barthel Index.

RESULTS

Analysis of covariance analysis showed that serum albumin levels were associated with depressive symptoms at 20 months after stroke. Multivariate analysis of covariance showed that disability scores at 3 days were associated with depressive symptoms at 20 months after stroke and after accounting for the age covariate. Stroke survivors were not clinically deficient in serum albumin.

CONCLUSIONS

Low serum albumin appears to be associated with depressive symptoms in elderly individuals long term post-stroke.