IgA/IgM responses to tryptophan and tryptophan catabolites (TRYCATs) are differently associated with prenatal depression, physio-somatic symptoms at the end of term and premenstrual syndrome

The bidirectional relationship of depression and disturbances in B cell homeostasis: Double trouble

Major depressive disorder (MDD) is a recurrent, persistent, and debilitating neuropsychiatric syndrome with an increasing morbidity and mortality, representing the leading cause of disability worldwide. The dysregulation of immune systems (including innate and adaptive immune systems) has been identified as one of the key contributing factors in the progression of MDD. As the main force of the humoral immunity, B cells have an essential role in the defense against infections, antitumor immunity and autoimmune diseases. Several recent studies have suggested an intriguing connection between disturbances in B cell homeostasis and the pathogenesis of MDD, however, the B-cell-dependent mechanism of MDD remains largely unexplored compared to other immune cells. In this review, we provide an overview of how B cell abnormality regulates the progression of MMD and the potential consequence of the disruption of B cell homeostasis in patients with MDD. Abnormalities of B-cell homeostasis not only promote susceptibility to MDD, but also lead to an increased risk of developing infection, malignancy and autoimmune diseases in patients with MDD. A better understanding of the contribution of B cells underlying MDD would provide opportunities for identification of more targeted treatment approaches and might provide an overall therapeutic benefit to improve the long-term outcomes of patients with MDD.

Inflammatory biomarkers and perinatal depression: A systematic review

BACKGROUND

Approximately 10 to 20% of pregnant women worldwide experience perinatal depression (PND), a depressive episode with onset during pregnancy or after childbirth. We performed a systematic review to identify, summarize and discuss studies on inflammatory biomarkers described in relation to PND.

METHOD

Inclusion criteria defined the selection of observational studies written in English, French, Spanish or Portuguese, that evaluate analytical levels of inflammatory molecules (protein levels) in biological fluids in women, with a diagnosis of depression using ICD/DSM diagnostic criteria or depressive symptoms assessed by standardized psychometric instruments, during pregnancy and/or postpartum. Case reports, experimental studies, reviews, qualitative analysis, meta-analysis, gray literature or replicated data were excluded. Three electronic databases were used for search (Pubmed, Web of Science and PsychInfo) and quality assessment of selected studies were performed using the Newcastle-Ottawa Scale. Data extraction included study design; number of subjects; obstetric information; tools and timepoints of depression and inflammatory markers assessment.

RESULTS

56 studies (sample size for cross-sectional and case-control studies ranging from 10 to 469; sample size for longitudinal studies ranging from 26 to 467), where the major aim was to analyze the association between depression and inflammatory biomarkers during pregnancy and postpartum period were included in this systematic review. Overall, the findings of our systematic review lend support to the hypothesis that several inflammatory markers may be associated with peripartum depressive symptoms. The associations were somewhat different looking at pregnancy compared to the delivery time-point and postpartum, and mainly referred to increased levels of IL-6, IL-8, CRP and TNF-α among depressed.

DISCUSSION

In summary, our systematic review findings provide evidence supporting the hypothesis that several inflammatory markers may correlate with peripartum depressive symptoms. However, our work also highlighted notable differences in the timing of biological sampling for inflammatory markers and in the methodologies used to assess depression during the perinatal period. Additionally, variations were observed in how inflammatory biomarkers and depression were approached, including their classification as exposure or outcome variables, and the timing of assessments. It is essential for future research to investigate the influence of biological fluids and the timing of assessments for both inflammatory biomarkers and depression to gain a deeper understanding of their association. This comprehensive exploration is pivotal for elucidating the intricate relationship between inflammation and perinatal depression.

Metabolites of progesterone in pregnancy: Associations with perinatal anxiety

BACKGROUND

Anxiety disorders are the most common psychiatric disorder during the perinatal period and one of the major risk factors for postpartum depression, yet we know little about biological factors in the etiology of perinatal anxiety. A growing literature points to neuroactive steroid (NAS) dysregulation in perinatal mental illness, but directionality has not been clearly demonstrated, results are not consistent, and no studies have investigated NAS in a population with pure anxiety without comorbid depression. We aimed to add to the limited literature by examining the association between anxiety without comorbid depression and metabolic pathways of NAS longitudinally across the peripartum.

METHODS

We measured anxiety symptoms by psychological scales and NAS levels using Gas Chromatography-Mass Spectrometry (GC-MS) at the second and third trimester (T2 and T3) and week 6 postpartum (W6) in n = 36 women with anxiety and n = 38 healthy controls. The anxiety group was determined by a data-driven approach, and cross-sectional and longitudinal statistical methods were used to examine the relationship between the study population and NAS.

RESULTS

We found that anxiety had a significant moderating effect on the relationship between progesterone and allopregnanolone, with no such effect for the relationships between progesterone and the intermediate (5α-DHP) or isomeric (isoallopregnanolone) compounds in this pathway, and no effects on the corresponding pathway converting progesterone to pregnanolone and epipregnanolone. We also found a less precipitous decline in the ratio of allopregnanolone to progesterone between T3 and W6 in the anxiety group compared to the non-anxiety group. A genotype analysis of a single-nucleotide polymorphism in the AKR1C2 gene demonstrated that the relationship of allopregnanolone to the intermediate metabolite, 5α-DHP, differed by genotype.

CONCLUSION

Our exploratory findings indicate that, for pregnant people with anxiety, metabolism is shunted more aggressively toward the endpoint of the progesterone to allopregnanolone metabolic pathway than it is for those without anxiety.

IDO/Kynurenine; novel insight for treatment of inflammatory diseases

Inflammation and oxidative stress play pivotal roles in pathogenesis of many diseases including cancer, type 2 diabetes, cardiovascular disease, atherosclerosis, neurological diseases, and inflammatory diseases such as inflammatory bowel disease (IBD). Inflammatory mediators such as interleukins (ILs), interferons (INF-s), and tumor necrosis factor (TNF)-α are related to an extended chance of inflammatory diseases initiation or progression due to the over expression of the nuclear factor Kappa B (NF-κB), signal transducer of activators of transcription (STAT), nod-like receptor family protein 3 (NLRP), toll-like receptors (TLR), mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR) pathways. These pathways are completely interconnected. Theindoleamine 2,3 dioxygenase (IDO) subset of the kynurenine (KYN) (IDO/KYN), is a metabolic inflammatory pathway involved in production of nicotinamide adenine dinucleotide (NAD + ). It has been shown that IDO/KYN actively participates in inflammatory processes and can increase the secretion of cytokines that provoke inflammatory diseases. Data were extracted from clinical and animal studies published in English between 1990-April 2022, which were collected from PubMed, Google Scholar, Scopus, and Cochrane library. IDO/KYN is completely associated with inflammatory-related pathways, thus leading to the production of cytokines such as TNF-α, IL-1β, and IL-6, and ultimately development and progression of various inflammatory disorders. Inhibition of the IDO/KYN pathway might be a novel therapeutic option for inflammatory diseases. Herein, we gathered data on probable interactions of the IDO/KYN pathway with induction of some inflammatory diseases.

The Cytokine, Chemokine, and Growth Factor Network of Prenatal Depression

BACKGROUND

Neuro-immune pathways are engaged in antenatal and postpartum depression.

AIMS

To determine if immune profiles influence the severity of prenatal depression above and beyond the effects of adverse childhood experiences (ACE), premenstrual syndrome (PMS), and current psychological stressors.

METHODS

Using the Bio-Plex Pro human cytokine 27-plex test kit, we assayed M1 macrophage, T helper (Th)-1, Th-2, Th-17, growth factor, chemokine, and T cell growth immune profiles as well as indicators of the immune inflammatory response system (IRS) and compensatory immunoregulatory system (CIRS) in 120 pregnant females in the early (<16 weeks) and late (>24 weeks) pregnancy. The Edinburgh Postnatal Depression Scale (EPDS) was used to assess severity of antenatal depression.

RESULTS

Cluster analyses showed that the combined effects of ACE, relationship dissatisfaction, unwanted pregnancy, PMS, and upregulated M1, Th-1, Th-2, and IRS immune profiles and the ensuing early depressive symptoms shape a stress-immune-depression phenotypic class. Elevated IL-4, IL-6, IL-8, IL-12p70, IL-15, IL-17, and GM-CSF are the cytokines associated with this phenotypic class. All immune profiles (except CIRS) were significantly associated with the early EPDS score, independent of the effects of psychological variables and PMS. There was a shift in immune profiles from early to late pregnancy, with an increase in the IRS/CIRS ratio. The late EPDS score was predicted by the early EPDS score, adverse experiences, and immune profiles, mainly the Th-2 and Th-17 phenotypes.

CONCLUSIONS

Activated immune phenotypes contribute to early and late perinatal depressive symptoms above and beyond the effects of psychological stressors and PMS.

Post-partum depression: From clinical understanding to preclinical assessments

Post-partum depression (PPD) with varying clinical manifestations affecting new parents remains underdiagnosed and poorly treated. This minireview revisits the pharmacotherapy, and relevant etiological basis, capable of advancing preclinical research frameworks. Maternal tasks accompanied by numerous behavioral readouts demand modeling different paradigms that reflect the complex and heterogenous nature of PPD. Hence, effective PPD-like characterization in animals towards the discovery of pharmacological intervention demands research that deepens our understanding of the roles of hormonal and non-hormonal components and mediators of this psychiatric disorder.

Plasma metabolic disturbances during pregnancy and postpartum in women with depression

Examining plasma metabolic profiling during pregnancy and postpartum could help clinicians understand the risk factors for postpartum depression (PPD) development. This analysis targeted paired plasma metabolites in mid-late gestational and 1 month postpartum periods in women with (n = 209) or without (n = 222) PPD. Gas chromatogram-mass spectrometry was used to analyze plasma metabolites at these two time points. Among the 170 objected plasma metabolites, principal component analysis distinguished pregnancy and postpartum metabolites but failed to discriminate women with and without PPD. Compared to women without PPD, those with PPD exhibited 37 metabolites with disparate changes during pregnancy and the 1-month postpartum period and an enriched citrate cycle. Machine learning and multivariate statistical analysis identified two or three compounds that could be potential biomarkers for PPD prediction during pregnancy. Our findings suggest metabolic disturbances in women with depression and may help to elucidate metabolic processes associated with PPD development.

Premenstrual syndrome incidence rate and risk factors among the working population in the Republic of Korea: a prospective cohort study

Background

Premenstrual syndrome (PMS) is the most common disease of the genitourinary tract in women. Although a sizeable proportion of women have symptoms or diagnosed PMS, its etiology remains unclear. The purpose of this cohort is to offer incidence and relevant risk factors of PMS among reproductive-aged Korean female workers.

Methods

Cohort data used were from the National Health Insurance Service–Female Employees (from 2007 to 2015) conducted by the NHIS. A total of 121,024 female workers were analyzed to estimate the incidence and hazard ratio of PMS. PMS data was based on information obtained from medical facility visits during an eight-year follow-up.

Results

The incidence of PMS was 7.0% during follow-up periods. In industrial classification, human health and social work activities have the highest incidence (9.0%) of PMS. Cumulative incidence of PMS has continuously increased by approximately 1% annually for eight years. Adjusted hazard ratio with 95% confidence interval was significantly higher in the 15–19 years old age group (2.81, 95%CI 2.35–3.36), manual worker (1.06, 95%CI 1.01–1.12), with anemia (1.13, 95%CI 1.06–1.20), and underweight (1.21, 95%CI 1.10–1.25) compared to those in the reference group.

Conclusion

This study describes the PMS status with trend and risk factors using follow-up design among women under a middle-aged working population. Further study is warranted for better understanding on the risk factors of PMS for reproductive-aged female workers.

Shared neuroimmune and oxidative pathways underpinning Chagas disease and major depressive disorder

The cellular and molecular basis to understand the relationship between Chagas disease (CD), a infection caused by Trypanosoma cruzi, and depression, a common psychiatric comorbidity in CD patients, is largely unknown. Clinical studies show an association between CD and depression and preclinical evidence suggests that depressive-like behaviors in T. cruzi infected mice are due, at least partially, to immune dysregulation. However, mechanistic studies regarding this issue are still lacking. Herein, we present and discuss the state of art of data on CD and depression, and revise the mechanisms that may explain the development of depression in CD. We also discuss how the knowledge generated by current and future data may contribute to the discovery of new mechanisms underlying depressive symptoms associated with CD and, hence, to the identification of new therapeutic targets, which ultimately may change the way we see and treat CD and its psychiatric comorbidities.

Prenatal IL-6 levels and activation of the tryptophan to kynurenine pathway are associated with depressive but not anxiety symptoms across the perinatal and the post-partum period in a low-risk sample

Depression and anxiety symptoms are highly prevalent among women during pregnancy and post-partum. Previous studies suggest that one of the pathophysiological underpinnings could be an enhanced metabolism of tryptophan (Trp) into kynurenine (Kyn) due to increased inflammation. However, the longitudinal changes in the Kyn pathway and the complex interplay with inflammation and stress in women with perinatal depressive or anxiety symptoms are incompletely understood. We examined a cohort of healthy women at 34-36 gestational weeks. One hundred and ten women were assessed for salivary cortisol and 97 participants were also assessed for serum levels of Trp, Kyn and Interleukin 6 (IL-6). Women filled in two screening questionnaires for depressive (Edinburgh Postnatal Depression Scale (EPDS)) and anxiety (State Trait Anxiety Inventory subscale (STAI-S)) symptoms at 34-36 gestational weeks, delivery, 3 and 12 months postpartum. Unexpectedly, lower prenatal Kyn levels were associated with higher depressive symptoms in late pregnancy. Furthermore, prenatal Trp levels and the Kyn/Trp ratio moderate the association between IL-6 levels and depressive symptoms during the perinatal and the post-partum period. We found no interactions between Trp and Kyn biomarkers and cortisol on depressive symptoms. The observed associations were more robustly found for depressive symptoms, whereas weak and non-significant effects were found for the trajectory of anxiety symptoms. Overall, our data support the involvement of the Trp to Kyn pathway and inflammation in the course of depressive but not anxiety symptoms in women from late pregnancy until one-year post-partum, providing new evidence on the mechanisms regulating emotions during pregnancy and after delivery in a low-risk sample.

In schizophrenia, psychomotor retardation is associated with executive and memory impairments, negative and psychotic symptoms, neurotoxic immune products and lower natural IgM to malondialdehyde

Objectives: Stable-phase schizophrenia comprises two distinct entities namely Major Neuro-Cognitive Psychosis (MNP) and simple NP (SNP), which are defined by neuroimmune and neurocognitive abnormalities.Methods: This study investigates associations of psychomotor retardation (PMR), clinical and biomarker characteristics of schizophrenia. We recruited 40 healthy controls and 79 schizophrenia patients and measured IgA responses to tryptophan catabolites (TRYCATs), IgM to malondialdehyde and nitroso (NO)-cysteinyl, CCL-11, an immune activation index based on cytokine levels, and motor screening task (MOT) scores.Results: PMR differentiated schizophrenia from controls and MNP from SNP. In addition, PMR was strongly associated with impairments in executive functions and episodic and semantic memory, psychotic, hostility, excitation, mannerism and negative (PHEMN) symptoms. Around 50% of the variance in PMR was predicted by the cumulative effects of the immune activation index, CCL-11, TRYCATs, NO-Cysteinyl and natural IgM. PRM can reliably be combined with PHEMN symptoms, memory and executive impairments into one latent vector reflecting overall severity of schizophrenia.Conclusions: PMR is a key psychopathological feature of schizophrenia mainly MNP. In addition, PMR may be driven by deficits in the compensatory immune-regulatory system and increased production of neurotoxic immune products, namely TRYCATs, IgM to NO-cysteinyl, and CCL-11, an endogenous cognition deteriorating chemokine.

Precision medicine in perinatal depression in light of the human microbiome

Perinatal depression is the most common complication of pregnancy and affects the mother, fetus, and infant. Recent preclinical studies and a limited number of clinical studies have suggested an influence of the gut microbiome on the onset and course of mental health disorders. In this review, we examine the current state of knowledge regarding genetics, epigenetics, heritability, and neuro-immuno-endocrine systems biology in perinatal mood disorders, with a particular focus on the interaction between these factors and the gut microbiome, which is mediated via the gut-brain axis. We also provide an overview of experimental and analytical methods that are currently available to researchers interested in elucidating the influence of the gut microbiome on mental health disorders during pregnancy and postpartum.

Dexmedetomidine Alleviates Postpartum Depressive Symptoms following Cesarean Section in Chinese Women: A Randomized Placebo-Controlled Study

OBJECTIVES

Few studies have investigated the prophylactic efficacy of dexmedetomidine (DEX) in postpartum depressive symptoms (PDS). A randomized double-blind placebo-controlled trial was conducted to investigate whether the administration of DEX, immediately after delivery and for patient-controlled intravenous analgesia (PCIA), can attenuate PDS.

METHODS

A total of 600 parturients scheduled for elective cesarean delivery under spinal anesthesia were randomly allocated into the control group (infusion with 0.9% normal saline after delivery and PCIA with sufentanil) and the DEX group (DEX infusion 0.5 μg/kg after delivery and PCIA with DEX plus sufentanil). The prevalence of postpartum depressive disorders was indicated by the Edinburgh Postnatal Depression Scale (EPDS). Postoperative analgesia, sedation, and sleep quality of parturients were also assessed.

RESULTS

Postpartum blues and PDS prevalence in the DEX, versus control, group were significantly lower (5.0% vs 14.1%, p<0.001; 5.7% vs 16.3%, p<0.001, respectively), especially in parturients with antenatal depression or moderate stress during pregnancy. Compared with the control group, the EPDS score at postpartum days 7 and 42 in the DEX group was significantly lower (4.23 ± 4.37 vs 1.93 ± 3.36, p<0.001; 4.68 ± 4.78 vs 1.99 ± 3.18, p<0.001, respectively), as was the incidence of postpartum self-harm ideation at postpartum days 7 and 42 in the DEX group versus the control group (1.1% vs 4.0%, p=0.03; 0.4% vs 2.9%, p=0.04, respectively). The pain score and the sleep quality in the DEX group were better than that in the control group (p<0.001).

CONCLUSION

The application of DEX in the early postpartum period can significantly attenuate the incidence of postpartum depressive disorders.

Shared microglial mechanisms underpinning depression and chronic fatigue syndrome and their comorbidities

In 2011, it was reviewed that a) there is a strong co-occurrence between major depression and chronic fatigue syndrome (CFS), with fatigue and physio-somatic symptoms being key symptoms of depression, and depressive symptoms appearing during the course of CFS; and b) the comorbidity between both disorders may in part be explained by activated immune-inflammatory pathways, including increased translocation of Gram-negative bacteria and increased levels of pro-inflammatory cytokines, such as interleukin (IL)-1. Nevertheless, the possible involvement of activated microglia in this comorbidity has remained unclear. This paper aims to review microglial disturbances in major depression, CFS and their comorbidity. A comprehensive literature search was conducted using the PubMed / MEDLINE database to identify studies, which are relevant to this current review. Depressed patients present neuroinflammatory alterations, probably related to microglial activation, while animal models show that a microglial response to immune challenges including lipopolysaccharides is accompanied by depressive-like behaviors. Recent evidence from preclinical studies indicates that activated microglia have a key role in the onset of fatigue. In chronic inflammatory conditions, such as infections and senescence, microglia orchestrate an inflammatory microenvironment thereby causing fatigue. In conclusion, based on our review we may posit that shared immune-inflammatory pathways and especially activated microglia underpin comorbid depression and CFS. As such, microglial activation and neuro-inflammation may be promising targets to treat the overlapping manifestations of both depression and CFS.

Breakdown of the Paracellular Tight and Adherens Junctions in the Gut and Blood Brain Barrier and Damage to the Vascular Barrier in Patients with Deficit Schizophrenia

Deficit schizophrenia is characterized by leaky intestinal tight and adherens junctions and bacterial translocation. Here we examine whether (deficit) schizophrenia is accompanied by leaky paracellular, transcellular, and vascular barriers in the gut and blood-brain barriers. We measured IgA responses to occludin, claudin-5, E-cadherin, and β-catenin (paracellular pathway, PARA); talin, actin, vinculin, and epithelial intermediate filament (transcellular pathway, TRANS); and plasmalemma vesicle-associated protein (PLVAP, vascular pathway) in 78 schizophrenia patients and 40 controls. IgA responses to claudin-5, E-cadherin, and β-catenin, the sum of the four PARA proteins, and the ratio PARA/TRANS were significantly higher in deficit schizophrenia patients than in nondeficit schizophrenia patients and controls. A large part of the variance in PHEMN (psychosis, hostility, excitation, mannerism, and negative) symptoms, psychomotor retardation, formal thought disorders, verbal fluency, word list memory, word list recall, and executive functions was explained by the PARA/TRANS ratio coupled with plasma IgA responses to Gram-negative bacteria, IgM to malondialdehyde, CCL-11 (eotaxin), IgA levels of the ratio of noxious to more protective tryptophan catabolites (NOX/PRO TRYCATs), and a plasma immune activation index. Moreover, IgA levels to Gram-negative bacteria were significantly associated with IgA to E-cadherin, β-catenin, and PLVAP, while IgA levels to claudin-5 were significantly predicted by IgA to E-cadherin, NOX/PRO TRYCAT ratio, Gram-negative bacteria, and CCL11. The phenomenology of the deficit syndrome is to a large extent explained by the cumulative effects of lowered natural IgM, breakdown of the paracellular and vascular pathways, increased bacterial translocation, peripheral immune-inflammatory responses, and indices of BBB breakdown.

Upregulation of the Intestinal Paracellular Pathway with Breakdown of Tight and Adherens Junctions in Deficit Schizophrenia

In 2001, the first author of this paper reported that schizophrenia is associated with an increased frequency of the haptoglobin (Hp)-2 gene. The precursor of Hp-2 is zonulin, a molecule that affects intercellular tight junction integrity. Recently, we reported increased plasma IgA/IgM responses to Gram-negative bacteria in deficit schizophrenia indicating leaky gut and gut dysbiosis. The current study was performed to examine the integrity of the paracellular (tight and adherens junctions) and transcellular (cytoskeletal proteins) pathways in deficit versus non-deficit schizophrenia. We measured IgM responses to zonulin, occludin, E-cadherin, talin, actin, and vinculin in association with IgA responses to Gram-negative bacteria, CCL-11, IgA responses to tryptophan catabolites (TRYCATs), immune activation and IgM to malondialdehyde (MDA), and NO-cysteinyl in 78 schizophrenia patients and 40 controls. We found that the ratio of IgM to zonulin + occludin/talin + actin + viculin (PARA/TRANS) was significantly greater in deficit than those in non-deficit schizophrenia and higher in schizophrenia than those in controls and was significantly associated with increased IgA responses to Gram-negative bacteria. IgM responses to zonulin were positively associated with schizophrenia (versus controls), while IgM to occludin was significantly associated with deficit schizophrenia (versus non-deficit schizophrenia and controls). A large part of the variance (90.8%) in negative and PHEM (psychosis, hostility, excitation, and mannerism) symptoms was explained by PARA/TRANS ratio, IgA to Gram-negative bacteria, IgM to E-cadherin and MDA, and memory dysfunctions, while 53.3% of the variance in the latter was explained by PARA/TRANS ratio, IgA to Gram-negative bacteria, CCL-11, TRYCATs, and immune activation. The results show an upregulated paracellular pathway with breakdown of the tight and adherens junctions and increased bacterial translocation in deficit schizophrenia. These dysfunctions in the intestinal paracellular route together with lowered natural IgM, immune activation, and production of CCL-11 and TRYCATs contribute to the phenomenology of deficit schizophrenia.

The role of tryptophan metabolism in postpartum depression

The Postpartum depression (PPD) is the most common postpartum psychiatric disorder, afflicting approximately 10%-20% of new mothers. Clinical symptoms of the PPD include depressive disorder, agitation, insomnia, anxiety and confusion, resulting in an increase in suicidal tendencies, thereby having significant impacts on the puerpera, newborn and their family. A growing body of data indicate a role for alterations in tryptophan metabolism in the PPD. The metabolism of tryptophan produces an array of crucial factors that can differentially regulate key physiological processes linked to the PPD. Importantly, an increase in stress hormones and immune-inflammatory activity drives tryptophan to the production of neuroregulatory kynurenine pathway products and away from the serotonin and melatonin pathways. This links the PPD to other disorders of depressed mood, which are classically associated with decreased serotonin and melatonin, coupled to increases in kynurenine pathway products. Several kynurenine pathway products, such as kynurenic acid and quinolinic acid, can have neuroregulatory effects, with consequences pathological underpinnings of the PPD. The current article reviews the role of alterations in tryptophan metabolism in the PPD.

Body image dissatisfaction in pregnant and non-pregnant females is strongly predicted by immune activation and mucosa-derived activation of the tryptophan catabolite (TRYCAT) pathway

OBJECTIVES

The aim of the present study is to delineate the associations between body image dissatisfaction in pregnant women and immune-inflammatory biomarkers, i.e., C-reactive protein (CRP), zinc and IgA/IgM responses to tryptophan and tryptophan catabolites (TRYCATs).

METHODS

We assessed 49 pregnant and 24 non-pregnant females and assessed Body Image Satisfaction (BIS) scores at the end of term (T1), and 2-4 days (T2) and 4-6 weeks (T3) after delivery. Subjects were divided in those with a lowered BIS score (≤ 3) versus those with a higher score.

RESULTS

Logistic regression analysis showed that a lowered T1 BIS score was predicted by CRP levels and IgA responses to tryptophan (negative) and TRYCATs (positive), perinatal depression, body mass index (BMI) and age. The sum of quinolinic acid, kynurenine, 3-OH-kynurenine and 3-OH-anthranilic acid (reflecting brain quinolinic acid contents) was the single best predictor. In addition, a large part of the variance in the T1, T2 and T3 BIS scores was explained by IgA responses to tryptophan and TRYCATs, especially quinolinic acid.

CONCLUSIONS

Body image dissatisfaction is strongly associated with inflammation and mucosa-derived IDO activation independently from depression, pregnancy, BMI and age. IgA responses to peripheral TRYCATs, which determine brain quinolinic acid concentrations, also predict body image dissatisfaction.

A neuro-immune, neuro-oxidative and neuro-nitrosative model of prenatal and postpartum depression

A large body of evidence indicates that major affective disorders are accompanied by activated neuro-immune, neuro-oxidative and neuro-nitrosative stress (IO&NS) pathways. Postpartum depression is predicted by end of term prenatal depressive symptoms whilst a lifetime history of mood disorders appears to increase the risk for both prenatal and postpartum depression. This review provides a critical appraisal of available evidence linking IO&NS pathways to prenatal and postpartum depression. The electronic databases Google Scholar, PubMed and Scopus were sources for this narrative review focusing on keywords, including perinatal depression, (auto)immune, inflammation, oxidative, nitric oxide, nitrosative, tryptophan catabolites (TRYCATs), kynurenine, leaky gut and microbiome. Prenatal depressive symptoms are associated with exaggerated pregnancy-specific changes in IO&NS pathways, including increased C-reactive protein, advanced oxidation protein products and nitric oxide metabolites, lowered antioxidant levels, such as zinc, as well as lowered regulatory IgM-mediated autoimmune responses. The latter pathways coupled with lowered levels of endogenous anti-inflammatory compounds, including ω3 polyunsaturated fatty acids, may also underpin the pathophysiology of postpartum depression. Although increased bacterial translocation, lipid peroxidation and TRYCAT pathway activation play a role in mood disorders, similar changes do not appear to be relevant in perinatal depression. Some IO&NS biomarker characteristics of mood disorders are found in prenatal depression indicating that these pathways partly contribute to the association of a lifetime history of mood disorders and perinatal depression. However, available evidence suggests that some IO&NS pathways differ significantly between perinatal depression and mood disorders in general. This review provides a new IO&NS model of prenatal and postpartum depression.

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.

Depressive, anxiety and hypomanic symptoms in schizophrenia may be driven by tryptophan catabolite (TRYCAT) patterning of IgA and IgM responses directed to TRYCATs

The aim of this study was to delineate the associations between the tryptophan catabolite (TRYCAT) pathway and affective symptoms in schizophrenia. Towards this end we measured immunoglobulin (Ig)A and IgM responses to relatively noxious TRYCATs, namely quinolinic (QA), xanthurenic (XA), picolinic (PA) acid and 3-OH-kynurenine (3HK), and generally protective TRYCATs, namely anthranilic (AA) and kynurenic (KA) acid in 80 patients with schizophrenia and 40 healthy controls. The Hamilton Rating Scale for Depression (HDRS) and anxiety (HAMA), Young Mania Rating Scale (YMRS) as well as the Positive and Negative Symptoms Scale of Schizophrenia (PANSS) were measured. Depression, anxiety and hypomanic as well as negative and positive symptoms were associated with increased IgA responses to PA. Increased IgA responses to XA were associated with anxiety, hypomanic and negative symptoms. Moreover, depressive, anxiety, hypomanic and negative symptoms were characterized by increased IgA responses to the noxious (XA+3HK+QA+PA)/protective (AA+KA) TRYCAT ratio. All symptom dimensions were associated with increased IgM responses to QA, while depressive, anxiety, positive and negative symptoms were accompanied by lowered IgM responses to 3HK. Hypomanic symptoms were additionally accompanied by lowered IgM responses to AA, and negative symptoms by increased IgM responses to KA. In conclusion, both shared and distinct alterations in the activity of the TRYCAT pathway, as well as its regulatory factors and consequences, may underpin affective and classical psychotic symptoms of schizophrenia. Increased mucosa-generated production of noxious TRYCATs, especially PA, and specific changes in IgM-mediated regulatory activities may be associated with the different symptom dimensions of schizophrenia.

Relation of plasma tryptophan concentrations during pregnancy to maternal sleep and mental well-being: The GUSTO cohort

BACKGROUND

Evidence suggests a relation between plasma tryptophan concentrations and sleep and mental well-being. As no studies have been performed in pregnant women, we studied the relation of plasma tryptophan concentrations during pregnancy with sleep quality, and mood during and after pregnancy.

METHODS

Pregnant women (n = 572) from the Growing Up in Singapore Towards healthy Outcomes study completed the Pittsburgh Sleep Quality Index (PSQI), the Edinburgh Postnatal Depression Scale (EPDS) and the State-Trait Anxiety Inventory (STAI) at 26-28 weeks gestation and three months post-delivery. Plasma tryptophan concentrations were measured at 26-28 weeks gestation. Poisson regressions estimated prevalence ratios (PR) for the association between tryptophan and poor sleep quality (PSQI global score > 5), probable antenatal depression (EPDS ≥ 15) and probable anxiety (STAI-state ≥ 41) were calculated adjusting for covariates.

RESULTS

Mean plasma tryptophan concentrations was 48.0µmol/L (SD: 8.09). Higher plasma tryptophan concentrations were associated with a lower prevalence of antenatal poor sleep quality adjusting for covariates [PR: 0.88 (95% CI 0.80, 0.97) per 10µmol/L], especially in those participants who also suffered from anxiety symptoms [PR: 0.80 (95% CI 0.67, 0.95)]. No associations were observed between tryptophan concentrations during pregnancy and postnatal sleep quality or mental well-being.

LIMITATION

Subjective measures were used to assess sleep and mental well-being.

CONCLUSIONS

We observed that higher plasma tryptophan concentrations were associated with a 12% lower prevalence of poor sleep quality during pregnancy, in particular among those with anxiety symptoms. These findings suggest the importance of having adequate tryptophan concentrations during pregnancy.

IgM-mediated autoimmune responses to oxidative specific epitopes, but not nitrosylated adducts, are significantly decreased in pregnancy: association with bacterial translocation, perinatal and lifetime major depression and the tryptophan catabolite (TRYCAT) pathway

Immunoglubulin (Ig)M responses directed to oxidative specific epitopes (OSEs) and nitric oxide (NO)-adducts are significantly associated with major depression and physio-somatic symptoms. End of term serum IgM responses to OSEs and NO-adducts were assayed in pregnant women with (n = 24) and without prenatal depression (n = 25) as well as in 24 non-pregnant women. Associations of IgM/IgA responses to Gram-negative gut commensal bacteria (leaky gut index) and IgA/IgM responses to tryptophan catabolites (TRYCATs) were analyzed. IgM responses to OSEs, but not NO-adducts, were significantly reduced at the end of term. There were no significant associations between IgM responses to OSEs and perinatal depression, whilst IgM responses to NO-adducts, especially NO-cysteinyl, were significantly associated with a lifetime major depression. IgM responses to OSEs and NO-cysteinyl were significantly associated with IgA/IgM responses to Gram-negative bacteria, especially Morganella morganii, Klebsiella pneumoniae and Citrobacter koseri. IgM responses to NO-adducts and OSEs, especially malondialdehyde and myristic acid, and C-reactive protein (CRP) were inversely associated with TRYCAT pathway activity, whilst a lifetime depression and Pseudomonas putida were positively associated. The attenuation of natural IgM-mediated responses to OSEs at the end of term may indicate lowered activity of this part of the compensatory (anti-)inflammatory reflex system and may be partly explained by lowered bacterial translocation. Increased IgM responses to NO-cysteinyl is a biomarker of lifetime depression and may be induced by bacterial translocation. Natural IgM-mediated autoimmune responses, increased nitrosylation and higher CRP levels may have negative regulatory effects on the TRYCAT pathway.

Physio-somatic symptoms in schizophrenia: association with depression, anxiety, neurocognitive deficits and the tryptophan catabolite pathway

To investigate the frequency of physio-somatic symptoms (PS) symptoms in schizophrenia and their relation to positive, negative and affective symptoms; neurocognitive deficits and impairments in the tryptophan catabolite (TRYCAT) pathway. Eighty four patients with schizophrenia and 40 healthy controls were assessed using the 12 item Fibromyalgia and Chronic Fatigue Syndrome Rating scale (FF) and scales for negative and positive symptoms, depression and anxiety. Cognitive functioning was tested using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Other assessments included: immunoglobulin (Ig)A and IgM responses to tryptophan catabolites (TRYCATs), namely quinolinic (QA), 3-OH-kynurenine (3HK), picolinic (PA), xanthurenic (XA) and kynurenic acid (KA) and anthranilic acid (AA). More than 50% of the patients studied had elevated levels of physio-somatic (PS) symptoms, significantly co-occurring with depression and anxiety, but not with negative or positive symptoms. PS symptoms were significantly associated with IgA/IgM responses to TRYCATs, including increased IgA responses to 3 HK, PA and XA, and lowered IgA to QA and AA. Fatigue, muscle pain and tension, autonomic and cognitive symptoms and a flu-like malaise were strongly associated with cognitive impairments in spatial planning and working memory, paired associative learning, visual sustained attention and attention set shifting. PS symptoms in schizophrenia aggregate with depression and anxiety symptoms and may be driven by TRYCAT patterning of IgA/IgM-responses, with IgA indicating mucosal-mediated changes and IgM indicating regulatory functions. As such, the patterning of IgA/IgM responses to TRYCATs may indicate differential TRYCATs regulation of neuronal and glia activity that act to regulate PS signalling in schizophrenia.

Deficit Schizophrenia Is Characterized by Defects in IgM-Mediated Responses to Tryptophan Catabolites (TRYCATs): a Paradigm Shift Towards Defects in Natural Self-Regulatory Immune Responses Coupled with Mucosa-Derived TRYCAT Pathway Activation

Deficit schizophrenia is accompanied by mucosa-associated activation of the tryptophan catabolite (TRYCAT) pathway, as indicated by increased IgA responses to noxious (NOX) TRYCATs, but not regulatory or protective (PRO) TRYCATs, suggesting increased neurotoxic, excitotoxic, inflammatory, and oxidative potential. No previous studies examined IgM-mediated autoimmune responses to the TRYCAT pathway in deficit versus nondeficit schizophrenia. We measured IgM responses to NOX TRYCATs, namely, quinolinic acid (QA), 3-OH-kynurenine (3HK), picolinic acid (PA), and xanthurenic (XA) acid, and PRO TRYCATs, including kynurenic acid (KA) and anthranilic acid (AA), in 40 healthy controls and 40 deficit and 40 nondeficit schizophrenic patients. We computed the IgM responses to NOX (QA + PA + 3HK + XA)/PRO (AA + KA) ratio and ∆ differences in IgA - IgM TRYCAT values and NOX/PRO ratio. Deficit schizophrenia is characterized by significantly attenuated IgM responses to all TRYCATs and NOX/PRO ratio and highly increased ∆IgA - IgM NOX/PRO ratio as compared to nondeficit schizophrenia and healthy controls. The negative symptoms of schizophrenia are significantly and positively associated with increased IgM responses directed against the KA/3HK ratio and ∆IgA - IgM NOX/PRO ratio. The findings support the view that deficit schizophrenia is a distinct subtype of schizophrenia that may be significantly discriminated from nondeficit schizophrenia. Deficit schizophrenia is accompanied by a highly specific defect in IgM isotype-mediated regulatory responses directed to the TRYCAT pathway. Lowered IgM regulatory responses together with mucosa-derived activation of the TRYCAT pathway may contribute to neuroprogression, negative symptoms, and deficit schizophrenia. All in all, a highly specific defect in the compensatory (anti-)inflammatory reflex system (CIRS), namely, natural IgM-mediated regulatory responses, may underpin deficit schizophrenia.

Interactions of Tryptophan and Its Catabolites With Melatonin and the Alpha 7 Nicotinic Receptor in Central Nervous System and Psychiatric Disorders: Role of the Aryl Hydrocarbon Receptor and Direct Mitochondria Regulation

Recent work indicates an intimate interaction of the tryptophan catabolite (TRYCAT) pathways with the melatonergic pathways, primarily via TRYCAT pathway induction taking tryptophan away from the production of serotonin, which is a necessary precursor for the melatonergic pathways. The alpha 7 nicotinic receptor may be significantly modulated by this interaction, given its inactivation by the TRYCAT, kynurenic acid, and its induction by melatonin. Similarly, the aryl hydrocarbon receptor is activated by both kynurenic acid and kynurenine, leading to CYP1A2 and melatonin metabolism, whereas melatonin may act to inhibit the aryl hydrocarbon receptor. These 2 receptors and pathways may therefore be intimately linked, with relevance to a host of intracellular processes of clinical relevance. In this article, these interactions are reviewed. Interestingly, mitochondria may be a site for direct interactions of these pathways and receptors, suggesting that their differential induction may not only be modulating neuronal, glia, and immune cell processes and activity but also be directly acting to regulate mitochondrial functioning. This is likely to have significant consequences as to how an array of diverse central nervous system and psychiatric conditions are conceptualized and treated.

Deficit, but Not Nondeficit, Schizophrenia Is Characterized by Mucosa-Associated Activation of the Tryptophan Catabolite (TRYCAT) Pathway with Highly Specific Increases in IgA Responses Directed to Picolinic, Xanthurenic, and Quinolinic Acid

Evidence suggests that activation of the tryptophan catabolite (TRYCAT) pathway is involved in the pathophysiology of schizophrenia. However, no previous study examined whether TRYCAT pathway activation is associated with deficit schizophrenia. We measured IgA responses to TRYCATs, namely quinolinic acid, picolinic acid, kynurenic acid, xanthurenic acid, and anthranilic acid and 3-OH-kynurenine, in 40 healthy controls and in schizophrenic patients with (n = 40) and without (n = 40) deficit, defined according to the Schedule for the Deficit Syndrome (SDS). Primary deficit schizophrenia is accompanied by an activated TRYCAT pathway as compared to controls and nondeficit schizophrenia. Participants with deficit schizophrenia show increased IgA responses to xanthurenic acid, picolinic acid, and quinolinic acid and relatively lowered IgA responses to kynurenic and anthranilic acids, as compared to patients with nondeficit schizophrenia. Both schizophrenia subgroups show increased IgA responses to 3-OH-kynurenine as compared to controls. The IgA responses to noxious TRYCATs, namely xanthurenic acid, picolinic acid, quinolinic acid, and 3-OH-kynurenine, but not protective TRYCATS, namely anthranilic acid and kunyrenic acid, are significantly higher in deficit schizophrenia than in controls. The negative symptoms of schizophrenia are significantly and positively associated with increased IgA responses directed against picolinic acid and inversely with anthranilic acid, whereas no significant associations between positive symptoms and IgA responses to TRYCATs were found. In conclusion, primary deficit schizophrenia is characterized by TRYCAT pathway activation and differs from nondeficit schizophrenia by a highly specific TRYCAT pattern suggesting increased excitotoxicity, cytotoxicity, and neurotoxicity, as well as inflammation and oxidative stress. The specific alterations in IgA responses to TRYCATs provide further insight for the biological delineation of deficit versus nondeficit schizophrenia.

Breast Feeding and Melatonin: Implications for Improving Perinatal Health

The biological underpinnings that drive the plethora of breastfeeding benefits over formula-feeding is an area of intense research, given the cognitive and emotional benefits as well as the offsetting of many childhood- and adult-onset medical conditions that breast-feeding provides. In this article, we review the research on the role of melatonin in driving some of these breastfeeding benefits. Melatonin is a powerful antioxidant, anti-inflammatory and antinociceptive as well as optimizing mitochondrial function. Melatonin is produced by the placenta and, upon parturition, maternal melatonin is passed to the infant upon breastfeeding with higher levels in night-time breast milk. As such, some of the benefits of breastfeeding may be mediated by the higher levels of maternal circulating night-time melatonin, allowing for circadian and antioxidant effects, as well as promoting the immune and mitochondrial regulatory aspects of melatonin; these actions may positively modulate infant development. Herein, it is proposed that some of the benefits of breastfeeding may be mediated by melatonin's regulation of the infant's gut microbiota and immune responses. As such, melatonin is likely to contribute to the early developmental processes that affect the susceptibility to a range of adult onset conditions. Early research on animal models has shown promising results for the regulatory role of melatonin.