Recent advances in psychoneuroimmunology: Inflammation in psychiatric disorders

Methamphetamine Use Disorder and Inflammation: A Case-Control Study

OBJECTIVE

Methamphetamine use disorder (MUD) is a global health condition that impairs a person's health which may result in morbidity and mortality. Inflammation is a crucial process playing a vital role in MUD. For this reason, it is necessary to examine biochemical parameters for follow-up and treatment alternatives.

METHODS

We aimed to reveal the relationship between inflammatory response and MUD by evaluating peripheral hemogram parameters, leukocyte count, subtypes, and their ratios to each other, systemic immune inflammation index (SII), monocyte/high-density lipoprotein (HDL) ratio, and human C-reactive protein (CRP) in adult men with MUD. We included 76 adult male participants in the patient group and 70 adult male participants in the control group. We calculated the neutrophil/lymphocyte rate (NLR), monocyte/lymphocyte rate (MLR), platelet/lymphocyte rate (PLR), and basophil/lymphocyte rate (BLR). In addition, we obtained the SII and the monocyte/HDL rate.

RESULTS

The patients' leukocyte (p<0.001), platelet (p<0.001), plateletcrit (PCT) (p=0.002), neutrophil (p<0.001), monocyte (p=0.002), CRP (p<0.001), NLR (p=0.001), PLR (p=0.004), MLR (p=0.009), SII (p<0.001) and monocyte/HDL ratio (p<0.001) were higher than the control group. We observed a significant and positive relationship between the daily methamphetamine intake, and methamphetamine use duration (p=0.002), PCT (p=0.044), neutrophil (p=0.021), NLR (p=0.001), PLR (p=0.004), MLR (p=0.029), and SII (p<0.001). Daily methamphetamine intake had a significant and positive effect on SII. A one-unit increase in daily methamphetamine intake elevated SII by 165.53 units.

CONCLUSION

The results confirm the presence of peripheral subclinical inflammation and systemic immune inflammation in adult men with MUD.

Inflammation, Immunonutritive, and Cardiovascular Risk Biomarkers in Men With Alcohol Use Disorder

OBJECTIVE

Alcohol Use Disorder (AUD) is a significant public health issue associated with serious health risks. This study aims to reveal the relationship between AUD and inflammatory, immunonutritive, and cardiovascular risk markers by evaluating hemogram and biochemistry parameters together in AUD.

METHOD

The data of 54 male patients with AUD and 45 male controls were included in the study. Sociodemographic-clinical data of the participants and Alcohol Use Disorders Identification Test (AUDIT) results were obtained from medical records. Systemic immune inflammation index (SII) was obtained with the platelet x neutrophil/lymphocyte formula; systemic immune response index (SIRI) was obtained with the monocyte x neutrophil/lymphocyte formula, plasma atherogenicity index (AIP) was obtained with the ratio of triglyceride to High-density Lipoprotein (HDL) cholesterol. C-Reactive Protein (CRP) albumin-lymphocyte (CALLY) index was obtained with the albumin x lymphocyte/CRP x 104 formula.

RESULTS

Aspartate aminotransferase (AST), Gamma Glutamyl Transferase (GGT) activities, neutrophil, CRP, ferritin, SII, and SIRI levels were significantly higher in those with AUD compared to controls. Laboratory results of those with AUD were consistent with atherogenic dyslipidemia; higher triglyceride and total cholesterol levels and AIP values were found compared to controls. The amount of alcohol consumed was a predictor for high SII, SIRI, and AIP levels. The CALLY index, which evaluates immune function, inflammation, and nutritional status together, was significantly lower in patients compared to controls. The amount of alcohol use and the total AUDIT score were predictors for a low CALLY index.

CONCLUSION

The results of this study support that AUD is a chronic inflammatory psychiatric disorder. We suggest that new inflammatory, immunonutritive, and cardiovascular biomarkers SII, SIRI, AIP, and CALLY index could be promising clinical tools to evaluate the severity, potential complications, and treatment response of AUD.

Patterns of adolescent perceived social support and inflammation in adulthood within major racial groups: Findings from a longitudinal, nationally representative sample

Inflammation, the body's protective response to injury and infection, plays a critical role in physical and mental health outcomes. Elevated chronic inflammation is implicated as a predictor of disease and all-cause mortality and is linked with several psychological disorders. Given that social support is associated with lower rates of mortality and psychopathology, the links between inflammation and social support are well-studied. However, there are many significant gaps related to both the specificity and generalizability of extant findings. There is a paucity of research on the association between social support and inflammation within different racial groups. Additionally, more research is warranted to understand whether social support from different sources uniquely contributes to inflammation, above and beyond other sources of support. Thus, the current study examined whether perceived emotional social support during adolescence predicted inflammation during adulthood within several racial groups. Participants (n = 3,390) were drawn from the National Longitudinal Study of Adolescent to Adult Health (Add Health), identified as either Asian, Black, Latinx, White, or Multiracial, and had complete data on study variables. Consistent with our hypotheses and previous research, greater perceived support during adolescence was associated with lower inflammation during adulthood, but only for White participants. Contrastingly, greater perceived support during adolescence was associated with higher inflammation during adulthood for individuals who identified as Asian, Latinx, Black, or Multiracial. Furthermore, patterns of social support and inflammation within each racial group varied by relationship type. These results highlight the importance of studying relationship processes and health outcomes within racial groups to understand their unique, lived experiences.

Neutrophil-lymphocyte and Platelet-lymphocyte Ratios among Adolescents with Substance Use Disorder: A Preliminary Study

Objective

Substance use disorder (SUD) is a serious public health problem affecting both the individual and the society, and substance use-related deaths and disability have been shown to increase gradually. Recent etiologic studies have reported that there is a relation between inflammatory parameters and psychiatric disorders. The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) used as an indicator of inflammation have been shown to be increased in various psychiatric disorders. In this study, we aimed to investigate the NLR and PLR in adolescents with SUD.

Methods

This study was conducted by retrospectively examining the records of 55 male adolescents who were followed up with SUD in a child and adolescent psychiatry outpatient clinic between November 2019−June 2020. Patients who had comorbid psychiatric disorder were included, and those who received any psychotropic medication were excluded. A total of 61 healthy male adolescents in the same age range without any psychiatric disorders were recruited as a control group. Neutrophil-lymphocyte-platelet counts were noted retrospectively from complete blood tests, and NLR-PLR were calculated.

Results

The NLR and PLR of adolescents with SUD were significantly higher than the healthy adolescents (p < 0.01, p < 0.01, respectively). In addition, conduct disorder, depression, and attention deficit/hyperactivity disorder, which were determined as the most common comorbid psychiatric disorders had no effects on NLR (p = 0.513, p = 0.584, p = 0.394, respectively) and PLR (p = 0.210, p = 0.346, p = 0.359, respectively).

Conclusion

The results of current study indicate that inflammatory processes may have a key role in the pathophysiology of SUD.

Integrated Analysis of Methylomic and Transcriptomic Data to Identify Potential Diagnostic Biomarkers for Major Depressive Disorder

Major depressive disorder (MDD) is a mental illness with high incidence and complex etiology, that poses a serious threat to human health and increases the socioeconomic burden. Currently, high-accuracy biomarkers for MDD diagnosis are urgently needed. This paper aims to identify novel blood-based diagnostic biomarkers for MDD. Whole blood DNA methylation data and gene expression data from the Gene Expression Omnibus database are downloaded. Then, differentially expressed/methylated genes (DEGs/DMGs) are identified. In addition, we made a systematic analysis of the DNA methylation on 5′-C-phosphate-G-3′ (CpGs) in all of the gene regions, as well as different gene regions, and then we defined a “dominant” region. Subsequently, integrated analysis is employed to identify the robust MDD-related blood biomarkers. Finally, a gene expression classifier and a methylation classifier are constructed using the random forest algorithm and the leave-one-out cross-validation method. Our results demonstrate that DEGs are mainly involved in the inflammatory response-associated pathways, while DMGs are primarily concentrated in the neurodevelopment- and neuroplasticity-associated pathways. Our integrated analysis identified 46 hypo-methylated and up-regulated (hypo-up) genes and 71 hyper-methylated and down-regulated (hyper-down) genes. One gene expression classifier and two DNA methylation classifiers, based on the CpGs in all of the regions or in the dominant regions are constructed. The gene expression classifier possessed the best predictive ability, followed by the DNA methylation classifiers, based on the CpGs in both the dominant regions and all of the regions. In summary, the integrated analysis of DNA methylation and gene expression has identified 46 hypo-up genes and 71 hyper-down genes, which could be used as diagnostic biomarkers for MDD.

Sleep and suicide: A systematic review and meta-analysis of longitudinal studies

The current review provides a quantitative synthesis of the empirical literature on sleep disturbance as a risk factor for suicidal thoughts and behaviors (STBs). A systematic search of PsycINFO, MEDLINE, and the references of prior reviews resulted in 41 eligible studies included in this meta-analysis. Sleep disturbance, including insomnia, prospectively predicted STBs, yielding small-to-medium to medium effect sizes for these associations. Complicating interpretation of these findings however, is that few studies of suicidal ideation and suicide attempts, as well as none of suicide deaths, assessed short-term risk (i.e., employed follow-up assessments of under a month). Such studies are needed to evaluate current conceptualizations of sleep dysregulation as being involved in acute risk for suicidal behavior. This want of short-term risk studies also suggests that current clinical recommendations to monitor sleep as a potential warning sign of suicide risk has a relatively modest empirical basis, being largely driven by cross-sectional or retrospective research. The current review ends with recommendations for generating future research on short-term risk and greater differentiation between acute and chronic aspects of sleep disturbance, and by providing a model of how sleep disturbance may confer risk for STBs through neuroinflammatory and stress processes and associated impairments in executive control.

Pro Re Nata Medication Use in Acute Care Adolescent Psychiatric Unit

Objective: Evidence to support the use of pro re nata (PRN) medication is limited, and the details of PRN use (indication, frequency of administration, patient characteristics) are rarely reported, particularly in youth populations. The goal of this study was to report on the pattern of PRN use over 6 years in an acute care psychiatric unit for adolescents. Methods: A retrospective chart review of patients' records from November 2012 to October 2018 was conducted. Variables extracted from electronic medical records included age, gender, race/ethnicity, clinical rating scores at admission (on a subset of patients), length of stay, psychotropic and nonpsychotropic PRN medication administration, timing of administration, discharge diagnosis, and discharge medication. Results: Records from 2961 individuals with a total 3937 admissions were analyzed. A total of 62% of admissions had at least one PRN medication administration. Severity of symptoms, as indicated by higher scores on clinical rating scales at admission, longer length of stay, and readmission were related to high PRN use. Patients with bipolar spectrum disorders received more psychotropic and nonpsychotropic PRN medications than other patients. Patients who were high psychotropic PRN users were also high nonpsychotropic PRN users. Conclusion: Despite the lack of clear evidence in support of the efficacy of PRN medications, they commonly used to control symptoms in acute care inpatient settings. Youth with severe symptoms utilized not only psychotropic PRN medication but also nonpsychotropic PRN more frequently, suggesting a possible role of systemic disorder among youth with serious mental illness. More research is necessary to examine the efficacy of PRN medications for managing targeted symptoms.

Potential application of helminth therapy for resolution of neuroinflammation in neuropsychiatric disorders

Neuropsychiatric disorders (NPDs) are among the major debilitating disorders worldwide with multiple etiological factors. However, in recent years, psychoneuroimmunology uncovered the role of inflammatory condition and autoimmune disorders in the etiopathogenesis of different NPDs. Hence, resolution of inflammation is a new therapeutic target of NPDs. On the other hand, Helminth infections are among the most prevalent infectious diseases in underdeveloped countries, which usually caused chronic infections with minor clinical symptoms. Remarkably, helminths are among the master regulator of inflammatory reactions and epidemiological studies have shown an inverse association between prevalence of autoimmune disorders with these infections. As such, changes of intestinal microbiota are known to be associated with inflammatory conditions in various NPDs. Conversely, helminth colonization alters the intestinal microbiota composition that leads to suppression of intestinal inflammation. In animal models and human studies, helminths or their antigens have shown to be protected against severe autoimmune and allergic disorders, decline the intensity of inflammatory reactions and improved clinical symptoms of the patients. Therefore, "helminthic therapy" have been used for modulation of immune disturbances in different autoimmunity illnesses, such as Multiple Sclerosis (MS) and Inflammatory Bowel Disease (IBD). Here, it is proposed that "helminthic therapy" is able to ameliorate neuroinflammation of NPDs through immunomodulation of inflammatory reactions and alteration of microbiota composition. This review discusses the potential application of "helminthic therapy" for resolution of neuroinflammation in NPDs.

Biological mechanisms of depression following treatment with interferon for chronic hepatitis C: A critical systematic review

BACKGROUND

A significant subset of patients infected by the hepatitis C virus (HCV) develops a major depressive episode (MDE) during Interferon-alpha (IFN-α) based immunotherapy. We performed a systematic review of studies which examined biological mechanisms contributing to the onset of a MDE during IFN-α-based immunotherapy for HCV.

METHODS

Major electronic databases were searched from inception up until 15th February 2016 for peer-reviewed prospective studies that had enrolled HCV infected patients who received IFN-α treatment. A diagnosis of MDE had to be established by means of a standardized diagnostic interview at baseline and endpoint.

RESULTS

Eight unique references met inclusion criteria. A total of 826 participants with HCV (37.3% females, mean age 46.7 years) were included in this systematic review. The overall MDE incidence rate was 34.8%, with follow-up ranging between 4 and 48 weeks. The methodological quality varied across selected studies. It was observed that Interleukin-6, salivary cortisol, arachidonic acid / eicosapentaenoicacid plus docosahexaenoic acid ratio, and genetic polymorphisms may present variations which are linked to a predisposition to INF-α-induced depression.

LIMITATIONS

A meta-analysis could not be performed due to the diverse biological mechanisms investigated and the lack of replicated evidence.

CONCLUSIONS

This systematic review indicates that several potential mechanisms may be implicated in the onset of a MDE following IFN-α-based immunotherapy for chronic HCV. However, replicated evidence is lacking and therefore the mechanisms involved in IFN-α-induced depression in humans remain unclear.

Effects of the modified electric convulsive treatment (MECT) on cell factors of schizophrenia

The expression of cell factors of schizophrenia and the effect of the modified electric convulsive treatment (MECT) were studied. In total, 156 patients with schizophrenia were selected, and divided into the drug group (70 cases) and the drug combined with MECT group (combined group) (86 cases) according to the treatment methods. In addition, 70 cases of healthy volunteers (control group) were selected according to the closest matching method based on 1:1 of age and gender. The drug treatment, consisted of anti-psychotic drugs, such as risperidone 2-8, quetiapine 300-750, ziprasidone 80-160 or aripiprazole 10-30 mg/day, and for the control group, we used the electric spasm therapeutic instrument, Thymatron^®IV Systems up to 6 times, 3 times a week. The levels of interleukin (IL)-10, IL-4, IL-6 and IL-1 were detected before and after treatment by ELISA. The positive and negative symptom scale (PANSS) was used to evaluate the efficiency. Before the treatment, IL-1 and IL-6 levels of drug and combined groups were significantly higher than those of the control group (P<0.05), while IL-4 and IL-10 had no difference with the control group. There was no significant difference of each factor between the drug and combined groups. After treatment, IL-1, IL-6 and IL-10 of the drug group did not change compared to the levels before treatment, but IL-4 increased significantly; IL-1 and IL-10 of the combined group did not change, while IL-4 and IL-6 increased significantly; IL-1, IL-4 and IL-6 of the drug and combined groups were significantly (P<0.05) higher than those in the control group, but not IL-10. IL-1, IL-4 and IL-6 levels of the combined group were significantly higher (P<0.05) than those of the drug group. After treatment, the PANSS scores of the two groups decreased and the combined group decreased more significantly (P<0.05). The reduction rate of the combined group was significantly higher (P<0.05) than that of the drug group. The total efficiency of the combined group was significantly higher than that of the drug group, and after comparing these levels, there was statistical significance (P<0.05). IL-1, IL-4, IL-6 and IL-10 levels of the drug and combined groups before treatment were not associated with PANSS scores and the variation of IL-1, IL-4, IL-6 and IL-10 of the drug and combined groups had no correlation with the reduction rate of the PANSS. The results showed that, cell factors of schizophrenia had an abnormal expression, and medication and MECT can affect the expression level. In addition, MECT can improve the effect in the treatment of schizophrenia, but had no obvious correlation with the change of cell factors.

Mast cell activation disease and the modern epidemic of chronic inflammatory disease

A large and growing portion of the human population, especially in developed countries, suffers 1 or more chronic, often quite burdensome ailments which either are overtly inflammatory in nature or are suspected to be of inflammatory origin, but for which investigations to date have failed to identify specific causes, let alone unifying mechanisms underlying the multiple such ailments that often afflict such patients. Relatively recently described as a non-neoplastic cousin of the rare hematologic disease mastocytosis, mast cell (MC) activation syndrome-suspected to be of greatly heterogeneous, complex acquired clonality in many cases-is a potential underlying/unifying explanation for a diverse assortment of inflammatory ailments. A brief review of MC biology and how aberrant primary MC activation might lead to such a vast range of illness is presented.

Adaptive Immunity in Schizophrenia: Functional Implications of T Cells in the Etiology, Course and Treatment

Schizophrenia is a severe and highly complex neurodevelopmental disorder with an unknown etiopathology. Recently, immunopathogenesis has emerged as one of the most compelling etiological models of schizophrenia. Over the past few years considerable research has been devoted to the role of innate immune responses in schizophrenia. The findings of such studies have helped to conceptualize schizophrenia as a chronic low-grade inflammatory disorder. Although the contribution of adaptive immune responses has also been emphasized, however, the precise role of T cells in the underlying neurobiological pathways of schizophrenia is yet to be ascertained comprehensively. T cells have the ability to infiltrate brain and mediate neuro-immune cross-talk. Conversely, the central nervous system and the neurotransmitters are capable of regulating the immune system. Neurotransmitter like dopamine, implicated widely in schizophrenia risk and progression can modulate the proliferation, trafficking and functions of T cells. Within brain, T cells activate microglia, induce production of pro-inflammatory cytokines as well as reactive oxygen species and subsequently lead to neuroinflammation. Importantly, such processes contribute to neuronal injury/death and are gradually being implicated as mediators of neuroprogressive changes in schizophrenia. Antipsychotic drugs, commonly used to treat schizophrenia are also known to affect adaptive immune system; interfere with the differentiation and functions of T cells. This understanding suggests a pivotal role of T cells in the etiology, course and treatment of schizophrenia and forms the basis of this review.

Zinc deficiency is common in several psychiatric disorders

BACKGROUND

Mounting evidence suggests a link between low zinc levels and depression. There is, however, little knowledge about zinc levels in older persons with other psychiatric diagnoses. Therefore, we explore the zinc status of elderly patients suffering from a wide range of psychiatric disorders.

METHODS

Clinical data and blood samples for zinc analyzes were collected from 100 psychogeriatric patients over 64 of age. Psychiatric and cognitive symptoms were assessed using the Montgomery and Aasberg Depression Rating Scale, the Cornell Scale for Depression in Dementia, the Mini-Mental State Examination, the Clockdrawing Test, clinical interviews and a review of medical records. In addition, a diagnostic interview was conducted using the Mini International Neuropsychiatric Interview instrument. The prevalence of zinc deficiency in patients with depression was compared with the prevalence in patients without depression, and the prevalence in a control group of 882 older persons sampled from a population study.

RESULTS

There was a significant difference in zinc deficiency prevalence between the control group (14.4%) and the patient group (41.0%) (χ(2) = 44.81, df = 1, p<0.001). In a logistic model with relevant predictors, zinc deficiency was positively associated with gender and with serum albumin level. The prevalence of zinc deficiency in the patient group was significantly higher in patients without depression (i.e. with other diagnoses) than in patients with depression as a main diagnosis or comorbid depression (χ(2) = 4.36, df = 1, p = 0.037).

CONCLUSIONS

Zinc deficiency is quite common among psychogeriatric patients and appears to be even more prominent in patients suffering from other psychiatric disorders than depression.

LIMITATIONS

This study does not provide a clear answer as to whether the observed differences represent a causal relationship between zinc deficiency and psychiatric symptoms. The blood sample collection time points varied in both the control group and the patient group. No data regarding zinc supplementation were collected.

The TRIPS (Toll-like receptors in immuno-inflammatory pathogenesis) Hypothesis: a novel postulate to understand schizophrenia

Mounting evidence indicates that immune activation and/or immuno-inflammatory reactions during neurodevelopment apparently contribute to the pathogenesis and progression of schizophrenia. One of the important environmental factors that is known to trigger immune activation/inflammatory responses during early pregnancy is prenatal infection. Recent understanding from animal studies suggests that prenatal infection induced maternal immune activation (MIA)/inflammation in congruence with oxidative/nitrosative stress can lead to neurodevelopmental damage and behavioral abnormalities in the offspring. Although the underlying precise mechanistic processes of MIA/inflammation are yet to be completely elucidated, it is being increasingly recognized that Toll-like receptors (TLRs) that form the first line of defense against invading microorganisms could participate in the prenatal infection induced immune insults. Interestingly, some of the TLRs, especially TLR3 and TLR4 that modulate neurodevelopment, neuronal survival and neuronal plasticity by regulating the neuro-immune cross-talk in the developing and adult brain could also be affected by prenatal infection. Importantly, sustained activation of TLR3/TLR4 due to environmental factors including infection and stress has been found to generate excessive reactive oxygen species (ROS)/reactive nitrogen species (RNS) as well as pro-inflammatory mediators during embryogenesis, which result into neuronal damage by necrosis/apoptosis. In recent times, ROS/RNS and immuno-inflammatory mediators are being increasingly linked to progressive brain changes in schizophrenia. Although a significant role of TLR3/TLR4 in neurodegeneration is gaining certainty, their importance in establishing a causal link between prenatal infection and immuno-inflammatory, oxidative and nitrosative stress (IO&NS) responses and influence on adult presentation of schizophrenia is yet to be ascertained. We review here the current knowledge generated from the animal and human studies on the role of TLRs in schizophrenia and finally propose the "TRIPS Hypothesis" (Toll-like receptors in immuno-inflammatory pathogenesis) to elucidate the underlying mechanism(s) of TLR-mediated risk of schizophrenia. Considering the established role of TLR3 and TLR4 in antiviral and antibacterial responses respectively, we believe that in some cases of schizophrenia where IO&NS responses are evident, prenatal infection might lead to neuroprogressive changes in a TLR3/TLR4-dependent way.

Variation in the major histocompatibility complex [MHC] gene family in schizophrenia: associations and functional implications

Schizophrenia is a chronic debilitating neuropsychiatric disorder with a complex genetic contribution. Although multiple genetic, immunological and environmental factors are known to contribute to schizophrenia susceptibility, the underlying neurobiological mechanism(s) is yet to be established. The immune system dysfunction theory of schizophrenia is experiencing a period of renewal due to a growth in evidence implicating components of the immune system in brain function and human behavior. Current evidence indicates that certain immune molecules such as Major Histocompatibility Complex (MHC) and cytokines, the key regulators of immunity and inflammation are directly involved in the neurobiological processes related to neurodevelopment, neuronal plasticity, learning, memory and behavior. However, the strongest support in favor of the immune hypothesis has recently emerged from on-going genome wide association studies advocating MHC region variants as major determinants of one's risk for developing schizophrenia. Further identification of the interacting partners and receptors of MHC molecules in the brain and their role in down-stream signaling pathways of neurotransmission have implicated these molecules as potential schizophrenia risk factors. More recently, combined brain imaging and genetic studies have revealed a relationship between genetic variations within the MHC region and neuromorphometric changes during schizophrenia. Furthermore, MHC molecules play a significant role in the immune-infective and neurodevelopmental pathogenetic pathways, currently hypothesized to contribute to the pathophysiology of schizophrenia. Herein, we review the immunological, genetic and expression studies assessing the role of the MHC in conferring risk for developing schizophrenia, we summarize and discuss the possible mechanisms involved, making note of the challenges to, and future directions of, immunogenetic research in schizophrenia.