A genetic predisposition to produce low levels of IL-10 is related to depressive symptoms: a pilot study of patients with end stage renal disease

Inflammatory Determinants and Associated Morbidity in Hemodialysis Patients

Hemodialysis deteriorates patients' physical, metabolic, and mental status. Clinical outcomes derived from inflammation determine a worse status but are less frequently identified. The objective of the study was to identify inflammatory determinants and the effect of SNP-related serum IL-6 and IL-10 levels on associated morbidity in hemodialysis. A sample of hemodialysis patients at IMSS Regional Hospital No.46 in Guadalajara (n = 85) were tested using the Malnutrition Inflammation Score (MIS) and Patient Health Questionnaire-9 (PHQ-9) to assess the associated morbidity. Serum cytokine levels were quantified by enzyme-linked immunosorbent assay (ELISA). The restriction fragment length polymorphism (RFLP) technique was used for analysis of IL-6-572C/G and IL-10-1082A/G. Using data visualization methods, we identified relevant determinants of inflammation. A simple regression model was constructed between predictors and targets with genotypes as covariates. Results showed malnutrition in 85.9% of patients and depressive symptoms in 50.6%. IL-10 was the most relevant inflammatory determinant, with regression coefficients (R2) between 0.05 and 0.11. The GG genotype of IL-10-1082 A/G evinced small effect on both clinical outcomes (δ of 0.35 and 0.37, respectively). Hemodialysis increases the associated morbidity, cytokines act as inflammatory determinants, and genetic variability contributes to the severity of clinical outcomes. Further studies need to refine the causal relationship between inflammation and CKD.

Evaluation of Inflammatory Response System (IRS) and Compensatory Immune Response System (CIRS) in Adolescent Major Depression

Purpose

Nowadays, the role of two tightly interconnected systems, the inflammatory response system (IRS) and the compensatory immune response system (CIRS) in depression, is increasingly discussed. Various studies indicate pro-inflammatory activity in adolescent depression; however, there is an almost complete lack of findings about IRS and CIRS balance. Thus, we aimed to assess different IRS and CIRS indices, profiles, and IRS/CIRS ratios in drug-naïve MDD patients at adolescent age, with respect to sex.

Patients and Methods

One hundred MDD adolescents (40 boys, average age: 15.4±1.2 yrs.) and 60 controls (28 boys, average age: 15.3±1.5 yrs.) were examined. Evaluated parameters were 1. plasma levels of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, interferon gamma, tumor necrosis factor alpha (TNF-α), soluble receptor of IL-6 (sIL-6R), soluble receptors of TNF-α (sTNF-R1, sTNF-R2); 2. profiles: IL-6 trans-signaling, M1 macrophage signaling, helper T lymphocytes (Th) 1 profile, regulatory T lymphocytes (Treg)+Th2, allIRS, and allCIRS; 3. IRS vs CIRS activity ratios: TNF-α/TNF-R1, TNF-α/TNF-R2, TNF-α/sTNF-Rs (ie sTNF-R1+sTNF-R2), Th1/Th2, Th1/Treg, Th1/Th2+Treg, M1/Th2, M1/Treg, M1/Treg+Th2, allIRS/allCIRS.

Results

MDD patients showed increased IL-4, IL-10, TNF-α, sIL-6R, Treg+Th2, allIRS, allCIRS, and TNF-α/sTNF-Rs, and decreased Th1/Th2+Treg. MDD females showed increased IL-10 and TNF-α compared to control females. MDD males showed increased IL-4, IL-10, sIL-6R, Treg+Th2, and TNF-α/TNF-R1 compared to control males. Increased sTNF-R1 was found in MDD males compared to MDD females. Positive correlations were found between CDI score and sIL-6R and IL-10 in the total group and between CDI score and IL-10 in adolescent males.

Conclusion

Our study for the first time extensively evaluated IRS and CIRS interactions revealing enhanced pro-inflammatory TNF-α signaling and IL-6 trans-signaling in association with increased IL-10- and IL-4-mediated anti-inflammatory activity in first-episode depression at the adolescent age. Moreover, results reflect the sex-specific simultaneous activation of IRS and CIRS pathways in adolescent depression.

Investigating inflammation in depression in the chronically ill: Theoretical model and perspectives

Background:

Inflammation is a risk factor for chronic physical illnesses. Evidence is building that inflammation is also a risk factor for mental illnesses making inflammation a common mechanism which could explain the high comorbidity between mental and physical illnesses.

Method:

Based on a systematic search, a review on factors associated with inflammation in the depressed chronically ill has been conducted. Relevant articles have been selected according to the methodological considerations (scope, sample size, type of analysis and bias).

Results:

Five categories of factors mediate the association between chronic physical and mental illnesses: (1) social–demographic factors, (2) social–economic background, (3) adverse health behaviours, (4) psychological stress and (5) genetics. Psychological therapies and medication also moderate this association. A theoretical model of the interplay between inflammation, depression and chronic physical illness is then presented.

Discussion:

Inflammation contribute to both chronic physical and mental illnesses. These conclusions support future advances in clinical and research practice, as well as training and education.

Genetic associations of fatigue and other symptoms following breast cancer treatment: A prospective study

Background

Cancer-related fatigue, mood disturbances, pain and cognitive disturbance are common after adjuvant cancer therapy, but vary considerably between individuals despite common disease features and treatment exposures. A genetic basis for this variability was explored in a prospective cohort.

Methods

Physical and psychological health of women were assessed prospectively following therapy for early stage breast cancer with self-report questionnaires. Participation in a genetic association sub-study was offered. Indices for the key symptom domains of fatigue, pain, depression, anxiety, and neurocognitive difficulties were empirically derived by principal components analysis from end-treatment questionnaires, and then applied longitudinally. Genetic associations were sought with functional single nucleotide polymorphisms (SNPs) in pro- and anti-inflammatory cytokine genes - tumour necrosis factor (TNF)-α (−308 ​GG), interferon (IFN)-ɣ (+874 ​TA), interleukin (IL)-10 (1082 ​GA and −592 CA), IL-6 (−174 ​GC), IL-1β (−511 ​GA).

Results

Questionnaire data was available for 210 participants, of whom 111 participated in the genetic sub-study. As expected, symptom domain scores generally improved over several months following treatment completion. Tumour and adjuvant treatment related factors were unassociated with either severity or duration of the individual symptom domains, but severity of symptoms at end-treatment was strongly associated with duration for each domain (all p ​< ​0.05). In multivariable analyses, risk genotypes were independently associated with: fatigue with IL-6 -174 ​GG/GC and IL-10 -1082 GG; depression and anxiety with IL-10 -1082 AA; neurocognitive disturbance: TNF-α −308 GG; depression IL-1β (all p ​< ​0.05). The identified SNPs also had cumulative effects in prolonging the time to recovery from the associated symptom domain.

Conclusions

Genetic factors contribute to the severity and duration of common symptom domains after cancer therapy.

•

Common symptoms following breast cancer treatment can be grouped into symptom domains.

•

Symptom domains are useful to describe patterns and trajectories of symptoms following breast cancer treatment.

•

Cytokine gene polymorphisms are associated with the severity and duration of symptom domains following cancer treatment.

•

The symptom severity at final treatment predicts the duration of symptoms.

Shared genetic risk factors for depression and stroke

BACKGROUND

The comorbidity of major depressive disorder (MDD) and stroke are common in clinic. There is a growing body of evidence suggesting a bi-directional relationship between stroke and depression. However, the mechanisms underlying the relationship between MDD and stroke are poorly investigated. Considering that both MDD and stroke can be heritable and are influenced by multiple risk genes, shared genetic risk factors between MDD and stroke may exist.

OBJECTIVE

The objective is to review the existing evidence for common genetic risk factors for both MDD and stroke and to outline the possible pathophysiological mechanisms mediating this association.

METHODS

A systematic review and meta-analysis was performed. Gene association studies regarding stroke and depression were searched in the database PubMed, CNKI, and Chinese Biomedical Literature Database before December 2018. Statistical analysis was performed using the software Revman 5.3.

RESULTS

Genetic polymorphisms of 4 genes, methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein E (ApoE) have been demonstrated to associate with the increased risk for both MDD and stroke, while the association between identified polymorphisms in angiotensin converting enzyme (ACE) and serum paraoxonase (PON1) with depression is still under debate, for the existing studies are insufficient in sample size. These results suggest the possible pathophysiological mechanisms that are common to these two disorders, including immune-inflammatory imbalance, increased oxidative and nitrative stress, dysregulation of lipoprotein and lipid metabolism, and changes of cerebrovascular morphology and function. Other associated genes with few or conflicting results have also been included, and a few studies have investigated the effects of the described polymorphisms on MDD and stroke comorbidity, such as post stroke depression.

CONCLUSION

These findings suggest that shared genetic pathways may contribute to the comorbidity of MDD and stroke. Studies to evaluate the shared genetic variations between MDD and stroke may provide insights into the molecular mechanisms that trigger disease progression.

Low-income homebound older adults receiving home-delivered meals: Physical and mental health conditions, incidence of falls and hospitalisations

Significant differences in health across racial/ethnic and socioeconomic groups in the US signal increasing numbers of low-income homebound older adults in a rapidly ageing society. The purpose of this study was to examine physical and psychiatric conditions and their association with incidence of self-reported falls and hospitalisations among largely low-income and racial/ethnic minority adults age 50+ (N = 2,224), clients from a home-delivered meals programme in Central Texas. Data came from comprehensive, in-home assessments done in 2017 by these older adults' case managers. We used bivariate analyses to compare those with and without incidence of self-reported past-year falls and those with and without a hospitalisation episode with respect to their sociodemographic and clinical characteristics. We used multivariable logistic regression analysis to examine sociodemographic and clinical correlates of any incidence of falls and negative binomial regression analysis to examine these correlates of the number of hospitalisations in the preceding 12 months. The rates of chronic physical illnesses, including cardiovascular disease, diabetes, gastrointestinal disease, lung disease and renal failure, were extremely high. The 41% of reported falls among the study sample was also higher than the rate among US older adults in general. More diagnosed physical illnesses, depression, chewing/swallowing problems, chronic/severe pain, activities and instrumental activities of daily living (ADL/IADL) impairments and ambulation assistive device use were associated with greater odds of falling. The rate of past-year hospitalisation was 26%, and more diagnosed physical illnesses, ADL/IADL impairments, ambulation assistive device use and any fall incidence were positively associated with the number of hospitalisations. These findings indicate the need for fall prevention programmes for frail homebound older adults as well as health and social care services that help older adults better manage physical/mental health problems and reduce preventable health crises and hospitalisations.

Resolution of inflammation-induced depression requires T lymphocytes and endogenous brain interleukin-10 signaling

In humans, depression is often associated with low-grade inflammation, activation of the tryptophan/kynurenine pathway, and mild lymphopenia. Preclinical research confirms that inflammation induces depression-like behavior through activation of the tryptophan/kynurenine pathway. However, the mechanisms governing recovery from depression are unknown. Understanding the pathways leading to resolution of depression will likely lead to identification of novel targets for treatment. We investigated the contribution of T lymphocytes to the resolution of lipopolysaccharide-induced depression-like behavior. Duration of depression-like behavior was markedly prolonged in mice without mature T or B lymphocytes (Rag1^-/- mice). This prolonged depression-like behavior was associated with persistent upregulation of the tryptophan-metabolizing enzyme indoleamine-2,3-dioxygenase (Ido)1 in the prefrontal cortex (PFC). Reconstitution of Rag1^-/- mice with T lymphocytes normalized resolution of depression-like behavior and expression of Ido1 in the PFC. During resolution of inflammation-induced depression-like behavior, T lymphocytes accumulated in the meninges and were required for induction of interleukin (IL)-10 in the meninges and the PFC. Inhibition of IL-10 signaling by nasal administration of neutralizing anti-IL-10 antibody to WT mice led to persistent upregulation of Ido1 in the PFC and prolonged depression-like behavior. Conversely, nasal administration of recombinant IL-10 in Rag1^-/- mice normalized Ido1 expression and resolution of depression-like behavior. In conclusion, the present data show for the first time that resolution of inflammation-induced depression is an active process requiring T lymphocytes acting via an IL-10-dependent pathway to decrease Ido1 expression in the brain. We propose that targeting the T lymphocyte/IL-10 resolution pathway could represent a novel approach to promote recovery from major depressive disorder.

Effects of a health education program on cytokines and cortisol levels in fibromyalgia patients: a randomized controlled trial

BACKGROUND

Fibromyalgia (FM) is a syndrome characterized by widespread chronic pain associated to other symptoms, such as: fatigue, anxiety, depression and sleep disorders. Health education programs (HEP) have emerged as good non-pharmacological strategies to treat it. However, it is still not clear if the benefits are only subjective, or it has also objective impacts on immune and or neuroendocrine systems.

METHODS

Fifty-eight fibromyalgia women were randomly allocated in experimental group (n = 27) or control group (n = 31). The experimental group was submitted to HEP treatment for 11 weeks, while control group did not receive intervention at the same period. All data were collected at zero and 11th week by a blinded researcher. The statistical analysis were made in GraphPad Prism software (version 5.0) with significant level adjusted for α = 0.05.

RESULTS

Forty-four patients concluded the full study, 21 in the experimental group and 23 in the control group. Intragroup and intergroup analysis revealed that treatment induced significant increases of IL-4 plasma levels, anti-inflammatory cytokine/inflammatory cytokine ratio (AC/IC ratio), salivary cortisol levels, in addition to significant decreases on FIQ scores. Intergroup variation analyses revealed also significant increases of IL-10 plasma levels.

CONCLUSION

The results presented suggest that this kind of HEP could induce subjective and objective changes (immune and neuroendocrine), that could explain, at least in part the improvement of fibromyalgia patient's health status. (Clinical Trial Registration Number - ReBEC - RBR-5tdnbr).

A study of association between regulatory polymorphism in the IL-10 gene promoter region and acute viral hepatitis, and acute liver failure

BACKGROUND

The level of inflammatory cytokine Interleukin (IL)-10 is increased in patients infected with hepatitis-related acute liver failure (ALF), and this was thought to be because of the regulatory polymorphism in the IL-10 gene promoter region. The present study was designed to analyze the possible association between IL-10 gene promoter polymorphism and acute viral hepatitis (AVH), and ALF. An attempt was made to quantify IL-10 levels at admission, during the hospital stay, and at the final outcome to study its relationship with liver injury among patients with AVH, ALF, and controls.

METHODS

The study included 40 patients each with ALF and AVH. IL-10 gene promoter polymorphism was detected by the PCR-RFLP method. Quantification of IL-10 was done using commercially available ELISA kits.

RESULTS

The individuals with -592 AC, -819 TC, -1082 AA genotypes were found to have a significantly higher risk of ALF whereas those with -592 AA and - 819 CC polymorphism were found to be less susceptible. Individuals with - 819 CC were found to be more susceptible to AVH while those with -592 AA and -819 TT were less susceptible as compared to controls. Mean serum IL-10 at admission was significantly elevated in patients with ALF (38.4±11.3 pg/mL) as compared to patients with AVH (16.7±5.4 pg/mL) and control population (8.3±3.6 pg/mL, p < 0.05).

CONCLUSION

Regulatory polymorphism in the IL-10 gene promoter has a possible and significant association with severity and outcome in patients with AVH and ALF. Raised levels of IL-10 could be predictive of prognosis in patients with ALF.

Differences in the association of inflammation and tryptophan with depressive symptoms between white and non-white chronic dialysis patients

OBJECTIVE

Possibly, different biochemical parameters are involved in the development of depressive symptoms in white and non-white dialysis patients. We examined whether the association between inflammation and depressive symptoms and between tryptophan and depressive symptoms differs between white and non-white dialysis patients and whether the association between inflammation and depressive symptoms is mediated by tryptophan degradation along the kynurenine pathway in both groups.

METHOD

Depressive symptoms were measured with the BDI-II. HsCRP, IL-1β, IL-6, IL-10, and TNFα and tryptophan and its degradation products kynurenine and 3-hydroxykynurenine were measured in 270 white and 220 non-white patients.

RESULTS

The presence of depressive symptoms was significantly higher in non-white patients (51%) than in white patients (37%) (P<0.01). Among white patients, HsCRP was significantly associated with depressive symptoms (β=0.6 (95% CI: 0.1-1.2)). Among non-white patients, significant associations with depressive symptoms were found for both HsCRP (β=1.0 (95% CI: 0.1-2.0)) and IL-6 (β=2.6 (95% CI: 0.8-4.4)). Tryptophan levels were only significantly associated with depressive symptoms in non-white patients (β=-0.3 (95% CI: -0.4--0.1)). Tryptophan degradation along the kynurenine pathway did not mediate the association between inflammatory markers and depressive symptoms in either group.

CONCLUSION

Our results indicate that for white and non-white dialysis patients different biochemical parameters are associated with depressive symptoms.

Immunological effects of behavioral activation with exercise in major depression: an exploratory randomized controlled trial

Major depression (MD) is associated with peripheral inflammation and increased cardiovascular risk. Regular physical exercise can have anti-inflammatory effects. The present study examined whether behavioral activation with exercise affects inflammatory processes in MD. Ninety-eight patients with MD were randomly assigned to cognitive-behavioral therapy (CBT) emphasizing exercise during behavioral activation (CBT-E), CBT with pleasurable low-energy activities as an active control condition (CBT-C) or a passive waiting list control group (WL). Plasma levels of C-reactive protein (CRP), interleukin (IL)-6, IL-10, lipopolysaccharide (LPS)-stimulated IL-6 production, and blood immune cell counts were analyzed at baseline and weeks 8 (post-behavioral activation) and 16 (post-treatment). Thirty non-depressed age- and sex-matched controls were included to examine potential immunological alterations in MD at baseline. Patients with MD exhibited higher levels of CRP, higher neutrophil and monocyte counts, lower IL-10 levels and reduced LPS-stimulated IL-6 production compared to controls (P<0.001-0.045). Multilevel modeling indicated that CBT-E was associated with increased anti-inflammatory IL-10 at weeks 8 and 16 compared to CBT-C and WL (P=0.004-0.018). CBT-E did not significantly affect other immunological makers in the total sample. A subgroup analysis including patients with potentially higher cardiovascular risk (CRP ⩾1 μg ml^-1) indicated that CRP was reduced in CBT-E compared to CBT-C (P<0.007) and marginally reduced compared to WL (P<0.085) after week 16. The present findings provide new insights into immunological effects of behavioral treatments against depression. Behavioral activation in conjunction with exercise may have the potential to reverse, in part, immunological alterations in MD.

Genetic Contributions of Inflammation to Depression

This paper describes the effects of immune genes genetic variants and mRNA expression on depression's risk, severity, and response to antidepressant treatment, through a systematic review on all papers published between 2000 and 2016. Our results, based largely on case-control studies, suggest that common genetic variants and gene-expression pathways are involved in both immune activation and depression. The most replicated and relevant genetic variants include polymorphisms in the genes for interleukin (IL)-1β, IL-6, IL-10, monocyte chemoattractant protein-1, tumor necrosis factor-alpha, C-reactive protein, and phospholipase A2. Moreover, increased blood cytokines mRNA expression (especially of IL-1β) identifies patients that are less likely to respond to conventional antidepressants. However, even for the most replicated findings there are inconsistent results, not only between studies, but also between the immune effects of the genetic variants and the resulting effects on depression. We find evidence that these discrepant findings may be explained, at least in part, by the heterogeneity of the depression immunophenotype, by environmental influences and gene × environment interactions, and by the complex interfacing of genetic variants with gene expression. Indeed, some of the most robust findings have been obtained in patients developing depression in the context of treatment with interferon-alpha, a widely used model to mimic depression in the context of inflammation. Further 'omics' approaches, through GWAS and transcriptomics, will finally shed light on the interaction between immune genes, their expression, and the influence of the environment, in the pathogenesis of depression.

Peripheral Immune Alterations in Major Depression: The Role of Subtypes and Pathogenetic Characteristics

Depression has been associated with peripheral inflammatory processes and alterations in cellular immunity. Growing evidence suggests that immunological alterations may neither be necessary nor sufficient to induce depression in general, but seem to be associated with specific features. Using baseline data from the Outcome of Psychological Interventions in Depression trial, this exploratory study examines associations between depression subtypes and pathogenetic characteristics (i.e., melancholic vs non-melancholic depression, chronic vs non-chronic depression, age of onset, cognitive-affective and somatic symptom dimensions) with plasma levels of C-reactive protein (CRP), interleukin (IL)-6, IL-10, and numbers of leukocyte subpopulations in 98 patients with major depression (MD) and 30 age and sex-matched controls. Patients with MD exhibited higher CRP levels, higher neutrophil and monocyte counts, lower IL-10 levels, and an increased neutrophil to lymphocyte ratio (NLR) than controls. Patient with later age of onset had higher levels of two inflammatory markers (CRP, NLR) and lower cytotoxic T cell counts after adjusting for sociodemographics, lifestyle factors, and antidepressants. Furthermore, lower anti-inflammatory IL-10 levels were related to more severe somatic depressive symptoms. These results confirm and extend previous findings suggesting that increased levels of CRP are associated with a later onset of depression and demonstrate that also NLR as a subclinical inflammatory marker is related to a later onset of depression.

Pathogenetic and Therapeutic Applications of Tumor Necrosis Factor-α (TNF-α) in Major Depressive Disorder: A Systematic Review

Major depressive disorder (MDD) is characterized by mood, vegetative, cognitive, and even psychotic symptoms and signs that can cause substantial impairments in quality of life and functioning. Up to now, the exact pathogenesis of MDD remains poorly understood. Recent research has begun to reveal that the pro-inflammatory cytokines, particularly, tumor necrosis factor-α (TNF-α), play an integral role in the pathophysiology of depressive disorders and the mechanism of antidepressant treatment. On the base of several observations: it is found that subsets of MDD patients have enhanced plasma levels TNF-α; antidepressant treatments had linked with the decline of TNF-α; central administration of TNF-α gives rise to sickness behavior which shares features with depression; and a blockade of it can ameliorate depressive symptomatology in animal models and clinical trials. In this review article, we focus on recent evidence linking TNF-α and MDD looking at data from animal and clinical studies, illustrating the pathophysiological role, susceptibility and its therapeutic application in depression. We conclude by discussing future directions for research, in particular the opportunities for the development of novel therapeutics that target TNF-α. This will be very important for designing preventative strategies and for the identification of new drug targets and preventative strategies.

Comorbidity between depression and inflammatory bowel disease explained by immune-inflammatory, oxidative, and nitrosative stress; tryptophan catabolite; and gut-brain pathways

The nature of depression has recently been reconceptualized, being conceived as the clinical expression of activated immune-inflammatory, oxidative, and nitrosative stress (IO&NS) pathways, including tryptophan catabolite (TRYCAT), autoimmune, and gut-brain pathways. IO&NS pathways are similarly integral to the pathogenesis of inflammatory bowel disease (IBD). The increased depression prevalence in IBD associates with a lower quality of life and increased morbidity in IBD, highlighting the role of depression in modulating the pathophysiology of IBD.This review covers data within such a wider conceptualization that better explains the heightened co-occurrence of IBD and depression. Common IO&NS underpinning between both disorders is evidenced by increased pro-inflammatory cytokine levels, eg, interleukin-1 (IL-1) and tumor necrosis factor-α, IL-6 trans-signalling; Th-1- and Th-17-like responses; neopterin and soluble IL-2 receptor levels; positive acute phase reactants (haptoglobin and C-reactive protein); lowered levels of negative acute phase reactants (albumin, transferrin, zinc) and anti-inflammatory cytokines (IL-10 and transforming growth factor-β); increased O&NS with damage to lipids, proteinsm and DNA; increased production of nitric oxide (NO) and inducible NO synthase; lowered plasma tryptophan but increased TRYCAT levels; autoimmune responses; and increased bacterial translocation. As such, heightened IO&NS processes in depression overlap with the biological underpinnings of IBD, potentially explaining their increased co-occurrence. This supports the perspective that there is a spectrum of IO&NS disorders that includes depression, both as an emergent comorbidity and as a contributor to IO&NS processes. Such a frame of reference has treatment implications for IBD when "comorbid" with depression.

Associations of cytokine genes with Alzheimer's disease and depression in an elderly Korean population

BACKGROUND

Inflammatory processes regulated by cytokines are important in the aetiology of Alzheimer's disease (AD) and depression. Differences in transcriptional activities associated with several genetic polymorphisms affect cytokine production. We investigated the involvement of alleles associated with higher production of proinflammatory and lower production of anti-inflammatory cytokines in AD and depression in a community-dwelling sample of elderly individuals.

METHOD

A total of 732 community-dwelling elders were clinically evaluated for AD applying the NINCDS-ADRDA criteria and for depression applying the Geriatric Mental State Schedule. Genotyping was performed for six proinflammatory (interleukin (IL)-1β -511C/T and +3953C/T, IL-6 -174G/C, IL-8 -251T/A, tumour necrosis factor (TNF)-α -850C/T) and two anti-inflammatory (IL-4 +33T/C, IL-10 -1082G/A) cytokines. The sums of risk alleles of proinflammatory and anti-inflammatory cytokine genes were estimated. Age, gender, education and apolipoprotein E genotype were considered covariates.

RESULTS

TNF-α -308G/A and IL-8 -251T/A were significantly associated with AD and IL-1β +3953C/T with late-life depression, while the significance of these associations was lost after Bonferroni correction. A greater number of risk alleles producing proinflammatory cytokines was significantly associated with AD, but not with depression, after adjustment for the covariates. No association was found between an increased number of risk alleles for anti-inflammatory cytokine production and either AD or depression.

CONCLUSIONS

The present findings support the inflammatory hypothesis in the aetiology of AD as measured by several cytokine genes associated with increased proinflammatory cytokine production.

Update on inflammation in chronic kidney disease

BACKGROUND

Despite recent advances in chronic kidney disease (CKD) and end-stage renal disease (ESRD) management, morbidity and mortality in this population remain exceptionally high. Persistent, low-grade inflammation has been recognized as an important component of CKD, playing a unique role in its pathophysiology and being accountable in part for cardiovascular and all-cause mortality, as well as contributing to the development of protein-energy wasting.

SUMMARY

The variety of factors contribute to chronic inflammatory status in CKD, including increased production and decreased clearance of pro-inflammatory cytokines, oxidative stress and acidosis, chronic and recurrent infections, including those related to dialysis access, altered metabolism of adipose tissue, and intestinal dysbiosis. Inflammation directly correlates with the glomerular filtration rate (GFR) in CKD and culminates in dialysis patients, where extracorporeal factors, such as impurities in dialysis water, microbiological quality of the dialysate, and bioincompatible factors in the dialysis circuit play an additional role. Genetic and epigenetic influences contributing to inflammatory activation in CKD are currently being intensively investigated. A number of interventions have been proposed to target inflammation in CKD, including lifestyle modifications, pharmacological agents, and optimization of dialysis. Importantly, some of these therapies have been recently tested in randomized controlled trials.

KEY MESSAGES

Chronic inflammation should be regarded as a common comorbid condition in CKD and especially in dialysis patients. A number of interventions have been proven to be safe and effective in well-designed clinical studies. This includes such inexpensive approaches as modification of physical activity and dietary supplementation. Further investigations are needed to evaluate the effects of these interventions on hard outcomes, as well as to better understand the role of inflammation in selected CKD populations (e.g., in children).

Association between depression and inflammatory/anti-inflammatory cytokines in chronic kidney disease and end-stage renal disease patients: a review of literature

Depression is a common psychiatric disorder in patients with advanced chronic kidney diseases (CKDs). Strong correlation has been reported between depression and patients' morbidity and mortality among dialysis patients. On the contrary, chronic inflammation may be a major contributor to morbidity and mortality in these patients. Elevated plasma levels of proinflammatory cytokines, especially C-reactive protein and interleukin (IL)-6, have been correlated with cardiovascular events, hospitalization, and all-cause and cardiovascular-associated mortality in dialysis patients. Studies suggested that inflammation-mediated atherosclerotic cardiovascular diseases are the possible reasons for depression-induced mortality among patients without renal diseases. Several studies found significant elevations in circulating levels of proinflammatory cytokines, particularly IL-6 and tumor necrosis factor-α, in patients with major depression. Furthermore, depressive mood and behaviors, including sadness and suicidal ideation, were observed in patients who received repeated injections of recombinant cytokines. A thorough literature review indicates that while depressive symptoms and elevated inflammatory cytokine levels coexist in CKD and dialysis patients, their association is uncertain. Depression seems to be more associated with elevated serum levels of IL-6 than other cytokines in these patients. Further studies are needed to clarify the possibility of a causal relationship between inflammation and depressive symptoms in CKD and dialysis patients.

Biological pathways, candidate genes, and molecular markers associated with quality-of-life domains: an update

BACKGROUND

There is compelling evidence of a genetic foundation of patient-reported quality of life (QOL). Given the rapid development of substantial scientific advances in this area of research, the current paper updates and extends reviews published in 2010.

OBJECTIVES

The objective was to provide an updated overview of the biological pathways, candidate genes, and molecular markers involved in fatigue, pain, negative (depressed mood) and positive (well-being/happiness) emotional functioning, social functioning, and overall QOL.

METHODS

We followed a purposeful search algorithm of existing literature to capture empirical papers investigating the relationship between biological pathways and molecular markers and the identified QOL domains.

RESULTS

Multiple major pathways are involved in each QOL domain. The inflammatory pathway has the strongest evidence as a controlling mechanism underlying fatigue. Inflammation and neurotransmission are key processes involved in pain perception, and the catechol-O-methyltransferase (COMT) gene is associated with multiple sorts of pain. The neurotransmitter and neuroplasticity theories have the strongest evidence for their relationship with depression. Oxytocin-related genes and genes involved in the serotonergic and dopaminergic pathways play a role in social functioning. Inflammatory pathways, via cytokines, also play an important role in overall QOL.

CONCLUSIONS

Whereas the current findings need future experiments and replication efforts, they will provide researchers supportive background information when embarking on studies relating candidate genes and/or molecular markers to QOL domains. The ultimate goal of this area of research is to enhance patients' QOL.

The role of immune genes in the association between depression and inflammation: a review of recent clinical studies

The role for dysregulation of the immune system in the pathogenesis of depressive disorder is well established, and emerging research suggests the role of an underlying genetic vulnerability. The purpose of this review is to summarize the existing literature on the genetic variants involved in neurobiological pathways associated with both immune activation and depression. Using PubMed, Scopus, The Cochrane Library, Embase, Ovid of Medline, PsycINFO and ISI web of Knowledge, we selected 52 papers which are relevant for this literature review. Findings across the literature suggest that functional allelic variants of genes for interleukin-1beta (IL)-1β, tumor necrosis factor-alpha (TNF-α) and C-reactive protein (CRP), as well as genetic variations affecting T-cell function, may increase the risk for depression. Moreover, single nucleotide polymorphisms (SNPs) in the IL-1β, IL-6 and IL-11 genes, and in those regulating T-cell function may be associated with reduced responsiveness to antidepressant therapy. There is also some evidence indicative of a role of genetic variants of the enzymes, Cyclo-oxygenase2 (COX-2) and Phospholipase2 (PLA2), in the aetiology of depression. Finally, SNPs in genes related to the serotonin pathway may play a fundamental role in the shared genetic liability to both immune activation and depressive symptoms. Our review confirms that genetic variants influence the biological mechanisms by which the innate immune system contributes to the development of depression. However, future studies are necessary to identify the molecular mechanisms underlying these associations.

Association between interleukin-10-819 promoter polymorphism and susceptibility to Crohn's disease: A meta-analysis

AIM: To explore the association between interleukin-10 (IL-10) 819T/C polymorphism and Crohn's disease susceptibility.

METHODS: A systematic search of electronic databases such as CBM, CNKI, PubMed, Elsevier and EMbase was performed to retrieve relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated using the RevMan 5.1.4 software, and publication bias was tested by Egger's regression test and Begg's test.

RESULTS: A total of 11 studies involving 1670 patients with Crohn's disease and 3312 healthy controls were identified. The results of meta-analyses showed no significant association between IL-10 819T/C polymorphism and susceptibility to Crohn's disease (for T/T vs C/C: OR = 0.90, 95% CI: 0.70 to 1.17; T/C vs C/C: OR = 0.84, 95% CI: 0.56 to 1.27; for dominant inheritance model: OR = 0.97, 95% CI 0.86 to 1.10; for recessive inheritance model: OR = 0.90, 95% CI: 0.71 to 1.14).

CONCLUSION: Current evidence strongly suggests that there is no significant association between IL-10 819T/C polymorphism and susceptibility to Crohn's disease.