Shared metabolic and immune-inflammatory, oxidative and nitrosative stress pathways in the metabolic syndrome and mood disorders

A pilot study of minocycline for the treatment of bipolar depression: Effects on cortical glutathione and oxidative stress in vivo

BACKGROUND

The antibiotic minocycline appears to promote neuroprotection through antioxidant and other mechanisms that may be relevant to the pathophysiology of bipolar disorder. The present study assessed the efficacy of minocycline in bipolar depression and examined the association between minocycline treatment and brain glutathione (GSH), an essential regulator of oxidative stress.

METHOD

Twenty patients with bipolar disorder experiencing acute depressive symptoms enrolled in an 8-week, open-label trial of adjuvant minocycline. Depression was assessed using the Montgomery-Asberg Depression Rating Scale (MADRS) and proton magnetic resonance spectroscopy (¹H MRS) measures of cortical GSH within a voxel prescribed in the precuneus and aspects of the occipital cortex were obtained from a subset of patients (n=12) before and after treatment.

RESULTS

The daily dose of minocycline at study end was 256mg (SD: 71mg). Treatment was associated with improvements in depression severity [MADRS score change: -14.6 (95% CI: -7.8 to -21.3)]. Ten patients (50%) were classified as responders based on a ≥50% reduction in MADRS score and 8 patients (40%) were classified as remitters (MADRS score ≤ 9). Higher baseline GSH levels were associated with greater improvement in MADRS score following treatment (ρ=0.51, p=0.05). Increases in GSH levels at study end were higher in non-responders than in responders (p=0.04).

LIMITATIONS

Small sample size, lack of a placebo group.

CONCLUSION

Minocycline may be an effective adjuvant treatment for bipolar depression, particularly in patients with high baseline GSH levels. Further research is needed to evaluate the potential of minocycline in this population.

Interplay Between the Gut-Brain Axis, Obesity and Cognitive Function

Obesity continues to be one of the major public health problems due to its high prevalence and co-morbidities. Common co-morbidities not only include cardiometabolic disorders but also mood and cognitive disorders. Obese subjects often show deficits in memory, learning and executive functions compared to normal weight subjects. Epidemiological studies also indicate that obesity is associated with a higher risk of developing depression and anxiety, and vice versa. These associations between pathologies that presumably have different etiologies suggest shared pathological mechanisms. Gut microbiota is a mediating factor between the environmental pressures (e.g., diet, lifestyle) and host physiology, and its alteration could partly explain the cross-link between those pathologies. Westernized dietary patterns are known to be a major cause of the obesity epidemic, which also promotes a dysbiotic drift in the gut microbiota; this, in turn, seems to contribute to obesity-related complications. Experimental studies in animal models and, to a lesser extent, in humans suggest that the obesity-associated microbiota may contribute to the endocrine, neurochemical and inflammatory alterations underlying obesity and its comorbidities. These include dysregulation of the HPA-axis with overproduction of glucocorticoids, alterations in levels of neuroactive metabolites (e.g., neurotransmitters, short-chain fatty acids) and activation of a pro-inflammatory milieu that can cause neuro-inflammation. This review updates current knowledge about the role and mode of action of the gut microbiota in the cross-link between energy metabolism, mood and cognitive function.

Metabolic/inflammatory/vascular comorbidity in psychiatric disorders; soluble epoxide hydrolase (sEH) as a possible new target

The common and severe psychiatric disorders, including major depressive disorder (MDD) and bipolar disorder (BD), are associated with inflammation, oxidative stress and changes in peripheral and brain lipid metabolism. Those pathways are implicated in the premature development of vascular and metabolic comorbidities, which account for considerable morbidity and mortality, including increased dementia risk. During endoplasmic reticulum stress, the soluble epoxide hydrolase (sEH) enzyme converts anti-inflammatory fatty acid epoxides generated by cytochrome p450 enzymes into their corresponding and generally less anti-inflammatory, or even pro-inflammatory, diols, slowing the resolution of inflammation. The sEH enzyme and its oxylipin products are elevated post-mortem in MDD, BD and schizophrenia. Preliminary clinical data suggest that oxylipins increase with symptoms in seasonal MDD and anorexia nervosa, requiring confirmation in larger studies and other cohorts. In rats, a soluble sEH inhibitor mitigated the development of depressive-like behaviors. We discuss sEH inhibitors under development for cardiovascular diseases, post-ischemic brain injury, neuropathic pain and diabetes, suggesting new possibilities to address the mood and cognitive symptoms of psychiatric disorders, and their most common comorbidities.

Associations between severity of anxiety and clinical and biological features of major affective disorders

Patients with major affective disorders (MAFD) with comorbid anxiety show a greater functional impairment than those without anxiety. The aim of this study is to delineate the associations between severity of anxiety in MAFD, namely bipolar disorder (BD) and major depression (MDD), and MAFD characteristics and serum high-density lipoprotein (HDL)-cholesterol levels. Recruited were 82 participants with anxiety disoders and 83 without anxiety disoders, including 101 MAFD patients and 51 healthy controls. We used the Hamilton Anxiety Rating Scale (HAM-A) to measure severity of anxiety and made the diagnoses of posttraumatic stress disorder (PTSD), obsessive compulsive disorder (OCD), panic disorder (PD), generalized anxiety disorder (GAD) and phobias. The HAM-A score is significantly predicted by higher number of depressive episodes, GAD and phobias, childhood trauma, tobacco use disorder, metabolic syndrome and lowered HDL-cholesterol. Increased HAM-A scores are, independently from severity of depression, associated with lowered quality of life, increased disabilities and suicidal ideation. Lithium treatment significantly lowers HAM-A scores. It is concluded that severity of anxiety significantly worsens the phenomenology of MAFD. Therefore, treatments of MAFD should target increased severity of anxiety and its risk factors including low HDL-cholesterol, metabolic syndrome, childhood trauma and tobacco use disorder.

Natural regulatory IgM-mediated autoimmune responses directed against malondialdehyde regulate oxidative and nitrosative pathways and coupled with IgM responses to nitroso adducts attenuate depressive and physiosomatic symptoms at the end of term pregnancy

AIM

We aimed to delineate the effects of immunoglobulin (Ig)M-mediated autoimmune responses directed against malondialdehyde (MDA) and nitroso (SNO) adducts on nitro-oxidative stress and depressive and physiosomatic symptoms (DPSS) at the end of term.

METHODS

IgM responses to MDA, NO (nitroso) adducts formed by nitrosylation, and NO₂ tyrosine formed by nitration were measured as well as hydroperoxides (ferrous oxidation xylenol orange), advanced protein oxidation products (AOPP), and NO metabolite (NOx) levels in women at the end of term pregnancy and in normal controls.

RESULTS

IgM responses to MDA were significantly and inversely associated with AOPP, ferrous oxidation xylenol orange, and NOx and DPSS. IgM responses to NO adducts were significantly and inversely associated with DPSS and positively with NOx levels. There were significant associations between IgM responses to MDA, NO adducts, and NO₂ tyrosine. The DPSS score was predicted by AOPP and a lifetime history of premenstrual syndrome (both positively) and IgM responses to NO adducts (inversely). Furthermore, 71.8% of the variance in the index of nitro-oxidative stress was explained by lowered IgM responses to MDA, antioxidant levels (zinc, total radical trapping parameter), and inflammatory mediators.

CONCLUSION

Lowered levels of IgM responses to MDA during pregnancy are accompanied by a reduced regulation of nitro-oxidative processes thereby explaining increased oxidative and nitrosative stress biomarkers in association with DPSS. IgM responses to NO adducts, which reflect nitrosylation as a consequence of increased NO production, regulate DPSS symptoms at the end of term and are a trait marker of major depression. IgM responses to MDA are a key part of the compensatory anti-inflammatory responses system.

Add-on Treatment with Curcumin Has Antidepressive Effects in Thai Patients with Major Depression: Results of a Randomized Double-Blind Placebo-Controlled Study

Activation of immune-inflammatory and oxidative-nitrosative (IO&NS) stress pathways plays a role in major depression (MDD). Evidence suggests that curcumin (500-1000 mg/day), a polyphenol with strong anti-IO&NS properties, may have efficacy either as monotherapy or as an adjunctive treatment for depression. Further controlled trials with extended treatment periods (> 8 weeks) and higher curcumin doses are warranted. This 12-week study was carried out to examine the effects of adjunctive curcumin for the treatment of MDD. In this double-blind, placebo-controlled trial, 65 participants with MDD were randomized to receive either adjunctive curcumin (increasing dose from 500 to 1500 mg/day) or placebo for 12 weeks. Four weeks after the active treatment phase, a follow-up visit was conducted at week 16. Assessments of the primary, i.e., the Montgomery-Asberg Depression Rating Scale (MADRS), and secondary, i.e., the Hamilton Anxiety Rating Scale (HAM-A), outcome measures were rated at baseline and 2, 4, 8, 12, and 16 weeks later. Curcumin was more efficacious than placebo in improving MADRS scores with significant differences between curcumin and placebo emerging at weeks 12 and 16. The effects of curcumin were more pronounced in males compared to females. There were no statistically significant treatment-emerging adverse effects and no significant effects of curcumin on blood chemistry and ECG measurements. Adjunctive curcumin has significant antidepressant effects in participants with MDD as evidenced by significant benefits occurring 12 and 16 weeks after treatment initiation. Curcumin administration was safe and well-tolerated even when combined with antidepressants. Future trials should include treatment-by-sex interactions to examine putative antidepressant effects of immune-modifying compounds.

Food addiction: Prevalence, psychopathological correlates and associations with quality of life in a large sample

OBJECTIVE

To determine the prevalence of food addiction in a large Brazilian non-clinical sample. Sociodemographic and psychopathological correlates of food addiction as well as associations with quality (QoL) domains were also investigated.

METHODS

This cross-sectional study obtained data from a Brazilian anonymous web-based research platform (N = 7639; 71.3% females). Participants provided sociodemographic data and completed the modified Yale Food Addiction Scale 2.0, PHQ-9, hypomania checklist (HCL-32), Fagerström Test for Nicotine Dependence, AUDIT, modified Skin picking-Stanford questionnaire, Minnesota impulsive disorders interview, Symptom Checklist-90-Revised inventory (SCL-90R), early trauma inventory self report-short form, and the WHO Quality of Life instrument-Abbreviated version (WHOQOL-Bref). Associations were adjusted to potential confounders through multivariable models.

RESULTS

The prevalence of food addiction was 4.32% (95%CI: 3.89-4.80%), and was more common among females. Food addiction was associated with a positive screen for a major depressive episode (OR = 4.41; 95%CI: 3.46-5.62), bipolar spectrum disorder (OR = 1.98; 95%CI: 1.43-2.75), and skin picking disorder (OR = 2.02; 95%CI: 1.31-3.09). Food addiction was also independently associated with exposure to early life psychological and sexual abuse (P = 0.008) as well as with reduced physical, psychological, social, and environment QoL (all P < 0.001).

CONCLUSIONS

Food addiction may be common in low and middle-income countries, though possibly less prevalent than in the US. Food addiction was associated with co-occurring mood disorders and skin picking disorder as well as with early life psychological and sexual abuse. Finally, food addiction was independently associated with broad reductions in QoL. Public health efforts towards the early recognition and management of food addiction are warranted.

Toward Precision Psychiatry in Bipolar Disorder: Staging 2.0

Personalized treatment is defined as choosing the "right treatment for the right person at the right time." Although psychiatry has not yet reached this level of precision, we are on the way thanks to recent technological developments that may aid to detect plausible molecular and genetic markers. At the moment there are some models that are contributing to precision psychiatry through the concept of staging. While staging was initially presented as a way to categorize patients according to clinical presentation, course, and illness severity, current staging models integrate multiple levels of information that can help to define each patient's characteristics, severity, and prognosis in a more precise and individualized way. Moreover, staging might serve as the foundation to create a clinical decision-making algorithm on the basis of the patient's stage. In this review we will summarize the evolution of the bipolar disorder staging model in relation to the new discoveries on the neurobiology of bipolar disorder. Furthermore, we will discuss how the latest and future progress in psychiatry might transform current staging models into precision staging models.

Neuroinflammatory reactions in sickness behavior induced by bacterial infection: Protective effect of minocycline

The neurological changes elicited by bacterial infection are called sickness behavior. Minocycline (MIN) is neuroprotective with a remarkable brain tissue penetration. MIN was orally administered at a dose 90 mg/kg for 3 days, whereas Escherichia coli was given as a single intraperitoneal injection (0.2 mL of 24 h growth) on the third day. After 24 h of bacterial infection, behavioral tests namely open field and forced swimming were carried out, then animals were decapitated. Rats infected with E. coli displayed reduced struggling time in forced swimming test, as well as, exploration and locomotion in open field test with reduction in neurotransmitters (norepinephrine, dopamine, and serotonin) versus elevation in the inflammatory (tumor necrosis factor-alpha, interferon-gamma) and oxidative stress (thiobarbituric acid reactive substance, reduced glutathione) biomarkers. Inflammatory infiltrates of nuclear cells were observed in brains of infected rats. MIN administration prevented the deleterious effects of E. coli infection, thus protects against sickness behavior possibly via defending from neuroinflammation.

Lipid profile and suicide attempt in bipolar disorder: A meta-analysis of published and unpublished data

Evidence suggests an association between low lipid levels and suicidality in subjects with severe mental disorders. This is the first systematic review and meta-analysis aimed at exploring differences in lipid profile between suicide attempters and non-attempters with bipolar disorder. We included observational studies providing comparative cross-sectional data on total cholesterol, LDL-cholesterol and triglycerides levels. We searched main Electronic Databases, identifying 11 studies that met our inclusion criteria, including also unpublished data. Meta-analyses based on random-effects models were carried out, generating pooled standardized mean differences (SMDs). Heterogeneity among studies was estimated using the I² index. The meta-analyses included data on lipid profile from 11 studies based on 288 subjects with and 754 without suicide attempt, respectively. No differences in total cholesterol (SMD: -0.10; 95%CI: -0.30 to 0.10; p=0.34), LDL-cholesterol (SMD: -0.26; 95%CI: -0.65 to 0.13; p=0.19), and triglycerides (SMD: -0.06; 95%CI: -0.31 to 0.19; p=0.63) were detected. Heterogeneity across studies was low-moderate and no risk of publication bias was found. Subgroup analyses showed no differences on effect size across different study characteristics, including different time-frames of suicide attempt, except for small sample size. Therefore, the evidence for an association between serum lipid profile and suicidality in bipolar disorder cannot be claimed. More research is needed to better understand the mechanisms underlying suicidal behaviours in bipolar patients, exploring further peripheral biomarkers as this may help clinicians screen and prevent suicidality.

The role of tryptophan metabolism and food craving in the relationship between obesity and bipolar disorder

BACKGROUND & AIMS

Individuals with bipolar disorder (BD) have a significantly increased risk of obesity-related conditions. The imbalance between food intake and energy expenditure is assumed to be a major risk factor for obesity in BD. This study analyzed food craving in relation to anthropometric, metabolic, and neurobiological parameters in a well-characterized cohort of euthymic individuals with BD.

METHODS

One-hundred-thirty-five patients completed the Food-Craving Inventory assessing four categories of food craving (fat, fast-food, sweets and carbohydrate craving). Additionally, clinical, metabolic and anthropometric parameters were assessed.

RESULTS

Higher levels of fat craving were observed in males, versus females, with BD. High levels of carbohydrate craving positively correlated with kynurenine and the kynurenine-to-tryptophan ratio. Higher serum nitrite and neopterin levels were related to fat craving. Parameters of fat metabolism (triglycerides, high-density lipoprotein) were associated with fat and fast-food craving. Anthropometric measures of obesity (e.g. body mass index, waist-to-hip-ratio) were not related to food craving.

CONCLUSIONS

Overweight/obese individuals with BD show an increased driving of tryptophan down the kynurenine pathways, as indicated by an increase in the serum kynurenine-to-tryptophan ratio. The driving of tryptophan down the kynurenine pathway is mediated by immune-inflammatory activity and stress. The correlation of increased kynurenine with food craving, especially carbohydrate craving, probably indicates a regulatory deficit in the maintenance of chronic inflammatory processes in obesity and BD. Food craving seems to be of clinical importance in the treatment of metabolic disturbances in BD, although not associated with anthropometric measures of obesity. Rather, food craving correlates with blood metabolic parameters and an increased activation of the kynurenine pathway, both of which are linked to higher affective symptomatology and the development of cardiovascular diseases.

Different Intestinal Microbial Profile in Over-Weight and Obese Subjects Consuming a Diet with Low Content of Fiber and Antioxidants

Obesity has been related to an increased risk of multiple diseases in which oxidative stress and inflammation play a role. Gut microbiota has emerged as a mediator in this interaction, providing new mechanistic insights at the interface between fat metabolism dysregulation and obesity development. Our aim was to analyze the interrelationship among obesity, diet, oxidative stress, inflammation and the intestinal microbiota in 68 healthy adults (29.4% normal-weight). Diet was assessed through a food frequency questionnaire and converted into nutrients and dietary compounds using food composition tables. The intestinal microbiota was assessed by quantitative PCR, fecal short chain fatty acids by gas chromatography and serum biomarkers by standard protocols. Higher levels of malondialdehyde (MDA), C reactive protein (CRP), serum leptin, glucose, fat percentage and the intestinal Lactobacillus group were found in the obese people. Cluster analysis of body mass index, fat mass, glucose, LDL/HDL ratio, leptin, MDA and CRP classified the subjects into two groups. The levels of the intestinal Bacteroides-Prevotella-Porphyromonas group were lower in the cluster and linked to a higher pro-oxidant and pro-inflammatory status, whose individuals also had lower intake of fruits, dried fruits, and fish. These results could be useful for designing strategies targeted to obesity prevention.