HPA and immune axes in stress: involvement of the serotonergic system

Protracted effects of chronic stress on serotonin-dependent thermoregulation

Chronic stress is known to affect serotonin (5HT) neurotransmission in the brain and to alter body temperature. The body temperature is controlled in part, by the medial preoptic area (mPOA) of the hypothalamus. To investigate the effect of chronic stress on 5HT and how it affects body temperature regulation, we examined whether exposure to a chronic unpredictable stress (CUS) paradigm produces long-term alterations in thermoregulatory function of the mPOA through decreased 5HT neurotransmission. Adult male Sprague-Dawley rats underwent 21 d of CUS. Four days after the last stress exposure, basal body temperature in the home cage and body temperature in a cold room maintained at 10 °C were recorded. The CUS rats had significantly higher subcutaneous basal body temperature at 13:00 h compared to unstressed (NoStress) rats. Whereas the NoStress rats were able to significantly elevate body temperature from basal levels at 30 and 60 min of exposure to the cold room, the CUS rats showed a hypothermic response to the cold. Treatment during CUS with metyrapone, a corticosterone synthesis inhibitor, blocked stress-induced decrease in body temperature in response to the cold challenge. CUS also decreased 5HT transporter protein immunoreactivity in the mPOA and 5HT2A/C agonist injection into the mPOA after CUS exposure caused stressed rats to exhibit a sensitized hyperthermic response to cold. These results indicate that the CUS induced changes to the 5HTergic system alter mPOA function in thermoregulation. These findings help us to explain the mechanisms underlying chronic stress-induced disorders such as chronic fatigue syndrome wherein long lasting thermoregulatory deficits are observed.

Cross-talk between HPA-axis-increased glucocorticoids and mitochondrial stress determines immune responses and clinical manifestations of patients with sepsis

Various stressors activate the hypothalamo-pituitary-adrenal axis (HPA-axis) that stimulates adrenal secretion of glucocorticoids, thereby playing critical roles in the modulation of immune responses. Transcriptional regulation of nuclear genes has been well documented to underlie the mechanism of glucocorticoid-dependent modulation of cytokine production and immune reactions. Glucocorticoids also regulate inflammatory responses via non-genomic pathways in cytoplasm and mitochondria. Recent studies have revealed that glucocorticoids modulate mitochondrial calcium homeostasis and generation of reactive oxygen species (ROS). Although redox status and ROS generation in inflammatory cells have been well documented to play important roles in defense against pathogens, the roles of glucocorticoids and mitochondria in the modulation of immunological responses remain obscure. This review describes the role of stress-induced activation of the HPA-axis and glucocorticoid secretion by the adrenal gland in mitochondria-dependent signaling pathways that modulate endotoxin-induced inflammatory reactions and innate immunity.

Safety and usefulness of Laghu shankha prakshalana in patients with essential hypertension: A self controlled clinical study

BACKGROUND

Yoga and Ayurveda texts emphasize the role of cleansing the bowel as an important component of management of hypertension (HTN). Observations during our clinical experience and pilot studies on Laghu shankha prakshalana kriya (LSP), a yogic bowel cleansing technique, appeared to be safe and complimentary.

OBJECTIVE

To test the safety and effectiveness of LSP in patients with essential hypertension.

MATERIALS AND METHODS

This self control study recruited 32 patients with mild to moderate essential HTN admitted for a week long residential integrated yoga therapy program at the integrative health home in Bengaluru. Patients had a daily routine of 6 hours of integrated approach of yoga therapy (IAYT) module for HTN that included physical postures, relaxation sessions, pranayama and meditations. LSP, an additional practice, that involved drinking of luke-warm water (with or without a herbal combination, triphala) followed by a set of specific yoga postures that activates defecation reflex, was administered on 2(nd) (LSP without triphala) and 5(th) day (LSP with triphala). Assessments (sitting blood pressure and pulse rate) were done just before and after both the sessions of LSP. Secondary outcome measures such as body mass index (BMI), symptom scores, medication scores, fatigue, state and trait anxiety, general health and quality of life were assessed on 1(st) and 6(th) day of IAYT intervention.

RESULTS

There was significant (P < 0.001, paired t test) reduction in blood pressure (systolic and diastolic) and pulse rate immediately after both the sessions (LSP with and without triphala). There were no adverse effects reported during or after LSP. There was no significant difference between the two techniques (P < 0.505, independent samples t test), although the percentage change appeared to be higher after triphala LSP session. The number of visits to clear the bowel during the procedure was significantly (P < 0.001, independent samples t test) higher after LSP with triphala than LSP without triphalā. After weeklong IAYT, there were significant reductions in blood pressure (P < 0.001), BMI (P < 0.004), medication score (P < 0.001), symptoms score (P < 0.001), fatigue (P < 0.001), state and trait anxiety (STAI, P < 0.001), scores of general ill health (GHQ, P < 0.001), and increase in comfort level (P < 0.001) and quality of sleep (P < 0.001).

CONCLUSION

LSP (a part of IAYT) is a safe and useful procedure for patients with essential hypertension. LSP with triphala is more useful.

Effect of yogic colon cleansing (Laghu Sankhaprakshalana Kriya) on pain, spinal flexibility, disability and state anxiety in chronic low back pain

Background:

Studies have shown that Integrated Yoga reduces pain, disability, anxiety and depression and increases spinal flexibility and quality-of-life in chronic low back pain (CLBP) patients.

Objective:

The objective of this study was to compare the effect of two yoga practices namely laghu shankha prakshalana (LSP) kriya, a yogic colon cleansing technique and back pain specific asanas (Back pain special technique [BST]) on pain, disability, spinal flexibility and state anxiety in patients with CLBP.

Materials and Methods:

In this randomized control (self as control) study, 40 in-patients (25 were males, 15 were females) between 25 and 70 years (44.05 ± 13.27) with CLBP were randomly assigned to receive LSP or BST sessions. The measurements were taken immediately before and after each session of either of the practices (30 min) in the same participant. Randomization was used to decide the day of the session (3^rd or 5^th day after admission) to ensure random distribution of the hang over effect of the two practices. Statistical analysis was performed using the repeated measures analysis of variance.

Results:

Significant group * time interaction (P < 0.001) was observed in 11 point numerical rating scale, spinal flexibility (on Leighton type Goniometer) and (straight leg raise test in both legs), Oswestry Disability Index, State Anxiety (XI component of Spieldberger's state and trait anxiety inventory. There was significantly (P < 0.001, between groups) better reduction in LSP than BST group on all variables. No adverse effects were reported by any participant.

Conclusion:

Clearing the bowel by yoga based colon cleansing technique (LSP) is safe and offers immediate analgesic effect with reduced disability, anxiety and improved spinal flexibility in patients with CLBP.

Comparative proteomic analysis of the breast muscle response to chronic corticosterone administration in broiler chickens showing long or short tonic immobility

Broilers of the same genetic origin were classified as short or long tonic immobility duration (STI and LTI, respectively) phenotypes and treated chronically with vehicle (control) or corticosterone (CORT) dissolved in drinking water between 27 and 42 d of age. Differential expression of proteins and mRNA was examined using 2-dimensional gel electrophoresis and real-time PCR to elucidate the mechanism behind the severe retardation of broiler breast muscle growth caused by LTI and CORT. The majority of the 13 proteins found to be differentially expressed in breast muscle of STI and LTI broilers are involved in either glycolysis (5 proteins) or myofilament formation (5 proteins). Of the 16 proteins differentially expressed in breast muscle following CORT treatment, 6 are structural proteins, 5 are categorized as cellular defense and stress proteins, and 3 (pyruvate kinase, l-lactate dehydrogenase, and creatine kinase) are involved in responses to stress and muscle damage. Real-time PCR results indicated that expression of these proteins is transcriptionally and posttranscriptionally regulated. Protein synthesis capacity, estimated by the RNA-to-protein ratio, was significantly lower in the breast muscle of CORT-treated broilers than in untreated control broilers. The level of Leu, Gly, and Ser in serum was significantly higher in CORT-treated broilers than in the control birds. Therefore, we conclude that CORT treatment retards the growth of skeletal muscle by suppressing protein synthesis and augmenting protein catabolism, paralleling the response to severe stress and muscle damage, and the negative effect of LTI on muscle growth is likely mediated through glucose metabolism. No interaction was observed between CORT and tonic immobility affecting growth performance or any parameter examined in the current study.

Dorsal prefrontal cortical serotonin 2A receptor binding indices are differentially related to individual scores on harm avoidance

Although the serotonergic system has been implicated in healthy as well as in pathological emotional states, knowledge about its involvement in personality is limited. Earlier research on this topic suggests that post-synaptic 5-HT2A receptors could be involved in particular in frontal cortical areas. In drug-naïve healthy individuals, we examined the relationship between these 5-HT2A receptors and the temperament dimension harm avoidance (HA) using 123I-5-I-R91150 single photon emission computed tomography (SPECT). HA is a personality feature closely related to stress, anxiety and depression proneness, and it is thought to be mediated by the serotonergic system. We focused on the prefrontal cortices as these regions are frequently implicated in cognitive processes related to a variety of affective disorders. We found a positive relationship between dorsal prefrontal cortical (DPFC) 5-HT2A receptor binding indices (BI) and individual HA scores. Further, our results suggest that those individuals with a tendency to worry or to ruminate are particularly prone to display significantly higher 5-HT2A receptor BI in the left DPFC. Although we only examined psychologically healthy individuals, this relationship suggests a possible vulnerability for affective disorders.

Mind and body: how the health of the body impacts on neuropsychiatry

It has long been established in traditional forms of medicine and in anecdotal knowledge that the health of the body and the mind are inextricably linked. Strong and continually developing evidence now suggests a link between disorders which involve Hypothalamic-Pituitary-Adrenal axis (HPA) dysregulation and the risk of developing psychiatric disease. For instance, adverse or excessive responses to stressful experiences are built into the diagnostic criteria for several psychiatric disorders, including depression and anxiety disorders. Interestingly, peripheral disorders such as metabolic disorders and cardiovascular diseases are also associated with HPA changes. Furthermore, many other systemic disorders associated with a higher incidence of psychiatric disease involve a significant inflammatory component. In fact, inflammatory and endocrine pathways seem to interact in both the periphery and the central nervous system (CNS) to potentiate states of psychiatric dysfunction. This review synthesizes clinical and animal data looking at interactions between peripheral and central factors, developing an understanding at the molecular and cellular level of how processes in the entire body can impact on mental state and psychiatric health.

Biological and psychological markers of stress in humans: focus on the Trier Social Stress Test

Validated biological and psychological markers of acute stress in humans are an important tool in translational research. The Trier Social Stress Test (TSST), involving public interview and mental arithmetic performance, is among the most popular methods of inducing acute stress in experimental settings, and reliably increases hypothalamic-pituitary-adrenal axis activation. However, although much research has focused on HPA axis activity, the TSST also affects the sympathetic-adrenal-medullary system, the immune system, cardiovascular outputs, gastric function and cognition. We critically assess the utility of different biological and psychological markers, with guidance for future research, and discuss factors which can moderate TSST effects. We outline the effects of the TSST in stress-related disorders, and if these responses can be abrogated by pharmacological and psychological treatments. Modified TSST protocols are discussed, and the TSST is compared to alternative methods of inducing acute stress. Our analysis suggests that multiple readouts are necessary to derive maximum information; this strategy will enhance our understanding of the psychobiology of stress and provide the means to assess novel therapeutic agents.

Common psychosocial stressors in middle-aged women related to longstanding distress and increased risk of Alzheimer's disease: a 38-year longitudinal population study

OBJECTIVE

To study the relation among psychosocial stressors, long-standing distress and incidence of dementia, in a sample of women followed from midlife to late life.

DESIGN

Prospective longitudinal population study.

SETTING

The analyses originate from the prospective population study of women in Gothenburg, Sweden, a representative sample of women examined in 1968 (participation rate 90%) and re-examined in 1974, 1980, 1992, 2000 and 2005.

PARTICIPANTS

800 women born in 1914, 1918, 1922 and 1930 who were systematically selected for a psychiatric examination at baseline, in 1968.

PRIMARY AND SECONDARY OUTCOME MEASURES

18 psychosocial stressors (eg, divorce, widowhood, work problems and illness in relative) were obtained at baseline. Symptoms of distress were measured according to a standardised question at each study wave. Dementia was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria based on information from neuropsychiatric examinations, informant interviews, hospital records, and registry data, and measured through the whole study period.

RESULTS

During the 37 years of follow-up, 153 women developed dementia (104 of those had Alzheimer's disease (AD)). Number of psychosocial stressors in 1968 was associated (HR, 95% CI) with higher incidence of dementia (1.15, 1.04 to 1.27) and AD (1.20, 1.07 to 1.35) between 1968 and 2005, in multivariate Cox regressions. Number of psychosocial stressors in 1968 was also associated (OR, 95% CI) with distress in 1968 (1.48, 1.32 to 1.67), 1974 (1.31, 1.17 to 1.46), 1980 (1.27, 1.11 to 1.45), 2000 (1.39, 1.14 to 1.70) and 2005 (1.35, 1.02 to 1.79), in multivariate logistic regressions. Number of psychosocial stressors (HR 1.17, 95% CI 1.03 to 1.33) and long-standing distress (1968-1974-1980) (HR 1.58, 95% CI 1.03 to 2.45) were independently associated with AD.

CONCLUSIONS

Our study shows that common psychosocial stressors may have severe and long-standing physiological and psychological consequences. However, more studies are needed to confirm these results and investigate whether more interventions such as stress management and behavioural therapy should be initiated in individuals who have experienced psychosocial stressors.

The microbiome-gut-brain axis during early life regulates the hippocampal serotonergic system in a sex-dependent manner

Bacterial colonisation of the intestine has a major role in the post-natal development and maturation of the immune and endocrine systems. These processes are key factors underpinning central nervous system (CNS) signalling. Regulation of the microbiome-gut-brain axis is essential for maintaining homeostasis, including that of the CNS. However, there is a paucity of data pertaining to the influence of microbiome on the serotonergic system. Germ-free (GF) animals represent an effective preclinical tool to investigate such phenomena. Here we show that male GF animals have a significant elevation in the hippocampal concentration of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid, its main metabolite, compared with conventionally colonised control animals. Moreover, this alteration is sex specific in contrast with the immunological and neuroendocrine effects which are evident in both sexes. Concentrations of tryptophan, the precursor of serotonin, are increased in the plasma of male GF animals, suggesting a humoral route through which the microbiota can influence CNS serotonergic neurotransmission. Interestingly, colonisation of the GF animals post weaning is insufficient to reverse the CNS neurochemical consequences in adulthood of an absent microbiota in early life despite the peripheral availability of tryptophan being restored to baseline values. In addition, reduced anxiety in GF animals is also normalised following restoration of the intestinal microbiota. These results demonstrate that CNS neurotransmission can be profoundly disturbed by the absence of a normal gut microbiota and that this aberrant neurochemical, but not behavioural, profile is resistant to restoration of a normal gut flora in later life.

Looking beyond the DNA sequence: the relevance of DNA methylation processes for the stress-diathesis model of depression

The functioning of the hypothalamic-pituitary-adrenal (HPA) axis and serotonergic (5-HT) system are known to be intertwined with mood. Alterations in these systems are often associated with depression. However, neither are sufficient to cause depression in and of themselves. It is now becoming increasingly clear that the environment plays a crucial role, particularly, the perinatal environment. In this review, we posit that early environmental stress triggers a series of epigenetic mechanisms that adapt the genome and programme the HPA axis and 5-HT system for survival in a harsh environment. We focus on DNA methylation as it is the most stable epigenetic mark. Given that DNA methylation patterns are in large part set within the perinatal period, long-term gene expression programming by DNA methylation is especially vulnerable to environmental insults during this period. We discuss specific examples of genes in the 5-HT system (serotonin transporter) and HPA axis (glucocorticoid receptor and arginine vasopressin enhancer) whose DNA methylation state is associated with early life experience and may potentially lead to depression vulnerability. We conclude with a discussion on the relevance of studying epigenetic mechanisms in peripheral tissue as a proxy for those occurring in the human brain and suggest avenues for future research.

Influence of mental stress on platelet bioactivity

It is well established that various mental stress conditions contribute, or at least influence, underlying pathophysiological mechanisms in somatic, as well as in psychiatric disorders; blood platelets are supposed to represent a possible link in this respect. The anculeated platelets are the smallest corpuscular elements circulating in the human blood. They display different serotonergic markers which seem to reflect the central nervous serotonin metabolism. They are known as main effectors in haematological processes but recent research highlights their role in the innate and adaptive immune system. Platelets are containing a multitude of pro-inflammatory and immune-modulatory bioactive compounds in their granules and are expressing immune-competent surface markers. Research gives hint that platelets activation and reactivity is increased by mental stress. This leads to enhanced cross talk with the immune system via paracrine secretion, receptor interaction and formation of platelet leucocyte-aggregates. Recently it has been demonstrated that the immune system can have a remarkable impact in the development of psychiatric disorders. Therefore platelets represent an interesting research area in psychiatry and their role as a possible biomarker has been investigated. We review the influence of mental stress on what is termed platelet bioactivity in this article, which subsumes the mainly immune-modulatory activity of platelets in healthy volunteers, elderly persons with chronic care-giving strain, patients with cardiovascular diseases who are prone to psychosocial stress, as well as in patients with posttraumatic stress disorder. Research data suggest that stress enhances platelet activity, reactivity and immune-modulatory capacities.

The endocannabinoid system: a revolving plate in neuro-immune interaction in health and disease

Studies of the last 40 years have brought to light an important physiological network, the endocannabinoid system. Endogenous and exogenous cannabinoids mediate their effects through activation of specific cannabinoid receptors. This modulatory homoeostatic system operates in the regulation of brain function and also in the periphery. The cannabinoid system has been shown to be involved in regulating the immune system. Studies examining the effect of cannabinoid-based drugs on immunity have shown that many cellular and cytokine mechanisms are modulated by these agents, thus raising the hypothesis that these compounds may be of value in the management of chronic inflammatory diseases. The special properties of endocannabinoids as neurotransmitters, their pleiotropic effects and the impact on immune function show that the endocannabinoid system represents a revolving plate of neural and immune interactions. In this paper, we outline current information on immune effects of cannabinoids in health and disease.

Midlife psychological distress associated with late-life brain atrophy and white matter lesions: a 32-year population study of women

OBJECTIVE

Long-standing psychological distress increases the risk of dementia, especially Alzheimer's disease. The present study examines the relationship between midlife psychological distress and late-life brain atrophy and white matter lesions (WMLs), which are common findings on neuroimaging in elderly subjects.

METHODS

A population-based sample of 1462 women, aged 38 to 60 years, was examined in 1968, with subsequent examinations in 1974, 1980, 1992, and 2000. Computed tomography (CT) of the brain was done in 379 survivors in 2000, and of those, 344 had responded to a standardized question about psychological distress in 1968, 1974, and 1980. WMLs, cortical atrophy, and central atrophy (ventricular sizes) were measured at CT scans.

RESULTS

Compared with women reporting no distress, those reporting frequent or constant distress at one examination or more (in 1968, 1974, and 1980) more often had moderate-to-severe WMLs (multiadjusted odds ratio = 2.39, 95% confidence interval = 1.16-4.92) and moderate-to-severe temporal lobe atrophy (multiadjusted odds ratio = 2.51, 95% confidence interval = 1.04-6.05) on brain CT in 2000. Frequent/constant distress was also associated with central brain atrophy, that is, higher bicaudate ratio, higher cella media ratio, and larger third-ventricle width.

CONCLUSIONS

Long-standing psychological distress in midlife increases risks of cerebral atrophy and WMLs on CT in late life. More studies are needed to confirm these findings and to determine potential neurobiological mechanisms of these associations.

Anxiety, Depression, and Somatic Distress: Developing a Transdiagnostic Internalizing Toolbox for Pediatric Practice

Anxiety, depression, and somatic complaints are a common set of comorbid problems in children and adolescents. This "internalizing cluster" is highly prevalent, impairing during youth and into adulthood, and has substantial impacts on health-care systems. Fortunately, these problem areas may share several etiological factors and, thus, respond to similar interventions. In this paper, we present (a) the rationale for focusing on this cluster, (b) clinical theory on transdiagnostic processes uniting these problems, (c) description of core treatment techniques for this group, with a description of clinical outcomes for two sample cases, and (d) implications of this approach for new transdiagnostic treatment development and everyday clinical practice.

Proinflammatory cytokines in the prefrontal cortex of teenage suicide victims

Teenage suicide is a major public health concern, but its neurobiology is not well understood. Proinflammatory cytokines play an important role in stress and in the pathophysiology of depression-two major risk factors for suicide. Cytokines are increased in the serum of patients with depression and suicidal behavior; however, it is not clear if similar abnormality in cytokines occurs in brains of suicide victims. We therefore measured the gene and protein expression levels of proinflammatory cytokines interleukin (IL)-1β, IL-6, and tissue necrosis factor (TNF)-α in the prefrontal cortex (PFC) of 24 teenage suicide victims and 24 matched normal control subjects. Our results show that the mRNA and protein expression levels of IL-1β, IL-6, and TNF-α were significantly increased in Brodmann area 10 (BA-10) of suicide victims compared with normal control subjects. These results suggest an important role for IL-1β, IL-6, and TNF-α in the pathophysiology of suicidal behavior and that proinflammatory cytokines may be an appropriate target for developing therapeutic agents.

Suppression of the HPA axis during extrahepatic biliary obstruction induces cholangiocyte proliferation in the rat

Cholestatic patients often present with clinical features suggestive of adrenal insufficiency. In the bile duct-ligated (BDL) model of cholestasis, the hypothalamic-pituitary-adrenal (HPA) axis is suppressed. The consequences of this suppression on cholangiocyte proliferation are unknown. We evaluated 1) HPA axis activity in various rat models of cholestasis and 2) effects of HPA axis modulation on cholangiocyte proliferation. Expression of regulatory molecules of the HPA axis was determined after BDL, partial BDL, and α-naphthylisothiocyanate (ANIT) intoxication. The HPA axis was suppressed by inhibition of hypothalamic corticotropin-releasing hormone (CRH) expression by central administration of CRH-specific Vivo-morpholinos or by adrenalectomy. After BDL, the HPA axis was reactivated by 1) central administration of CRH, 2) systemic ACTH treatment, or 3) treatment with cortisol or corticosterone for 7 days postsurgery. There was decreased expression of 1) hypothalamic CRH, 2) pituitary ACTH, and 3) key glucocorticoid synthesis enzymes in the adrenal glands. Serum corticosterone and cortisol remained low after BDL (but not partial BDL) compared with sham surgery and after 2 wk of ANIT feeding. Experimental suppression of the HPA axis increased cholangiocyte proliferation, shown by increased cytokeratin-19- and proliferating cell nuclear antigen-positive cholangiocytes. Conversely, restoration of HPA axis activity inhibited BDL-induced cholangiocyte proliferation. Suppression of the HPA axis is an early event following BDL and induces cholangiocyte proliferation. Knowledge of the role of the HPA axis during cholestasis may lead to development of innovative treatment paradigms for chronic liver disease.

Effect of yoga on quality of life of CLBP patients: A randomized control study

CONTEXT

In two of the earlier Randomized Control Trials on yoga for chronic lower back pain (CLBP), 12 to 16 weeks of intervention were found effective in reducing pain and disability.

AIM

To study the efficacy of a residential short term intensive yoga program on quality of life in CLBP.

MATERIALS AND METHODS

About 80 patients with CLBP (females 37) registered for a week long treatment at SVYASA Holistic Health Centre in Bengaluru, India. They were randomized into two groups (40 each). The yoga group practiced a specific module for CLBP comprising of asanas (physical postures), pranayama (breathing practices), meditation and lectures on yoga philosophy. The control group practiced physical therapy exercises for back pain. Perceived stress scale (PSS) was used to measure baseline stress levels. Outcome measures were WHOQOL Bref for quality of life and straight leg raising test (SLR) using a Goniometer.

RESULTS

There were significant negative correlations (Pearson's, P<0.005, r>0.30) between baseline PSS with all four domains and the total score of WHOQOLBref. All the four domains' WHOQOLBref improved in the yoga group (repeated measures ANOVA P=0.001) with significant group*time interaction (P<0.05) and differences between groups (P<0.01). SLR increased in both groups (P=0.001) with higher increase in yoga (31.1 % right, 28.4 % left) than control (18.7% right, 21.5 % left) group with significant group*time interaction (SLR right leg P=0.044).

CONCLUSION

In CLBP, a negative correlation exists between stress and quality of life. Yoga increases quality of life and spinal flexibility better than physical therapy exercises.

Immune and neuroimmune alterations in mood disorders and schizophrenia

A large number of publications over the past 20 years have indicated that immune system function is altered in schizophrenia and mood disorder patients. This chapter reviews the evidence, which suggests that a proinflammatory state of the cytokine network induces psychopathologic symptoms and may be involved in the pathogenesis and pathophysiology of these major mental illnesses. The authors also present recent data, which relates immune activation to present theories on the influence of activated immune cells in altering brain function. They also focus on the role of the environment in immune activation and on the role of the microbiome and gut flora. Increased understanding of such factors could help in the development of novel treatment strategies and improved clinical management of mental disorders.

The more physical inactivity, the more agitation in dementia

Epidemiological studies show a close relationship between physical activity and cognition. A causal relationship between physical activity and cognition has been observed in children, adolescents, older people without dementia, and in older people in a very early stage of dementia. Considering these positive effects, we argue that a decline in physical activity has a detrimental effect on cognition and behavior in patients with dementia. Merely living in a nursing home reduces the level of physical activity. The level of physical activity may even be reduced to a minimum when physical restraints are applied. The use of physical restraints coincides with stress, further aggravating the already existing neuropathology, which may increase stress and agitation even more. Exercise may reduce stress and agitation.

Effects of stress of postnatal development on corticosterone, serotonin and behavioral changes

Stressful events early in life are associated with later psychiatric disorders. We focused on developmental stage and evaluated changes in the corticosterone and serotonergic systems as well as in later anxiety-related behavioral tests. Stressed male Wistar rats were divided into two groups: stressed from postnatal day 11 (PND 11) to 15 and stressed from PND 16 to 20. The rats were exposed to an elevated open platform. Stress increased corticosterone in both experimental groups. In the hypothalamus, amygdala and hippocampus, 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) increased in the rats stressed from PND 11 to 15, and decreased in the rats stressed from PND 16 to 20. In a later behavioral test, rats stressed from PND 11 to 15 traveled shorter distances and tended to spend less time in the center than control rats following restraint stress. There were no significant changes in 5-HT and 5-HIAA in hypothalamus, amygdala and hippocampus after restraint stress in adults. These findings indicate that stress reactions and later effects are different depending on the developmental stage during which the rats were stressed. Stress during the PND 11-15 period may enhance later anxiety-related behaviors without altering 5-HT and 5-HIAA content.

Midlife psychological stress and risk of dementia: a 35-year longitudinal population study

The number of people with dementia has increased dramatically with global ageing. Nevertheless, the pathogeneses of these diseases are not sufficiently understood. The present study aims to analyse the relationship between psychological stress in midlife and the development of dementia in late-life. A representative sample of females (n = 1462) aged 38-60 years were examined in 1968-69 and re-examined in 1974-75, 1980-81, 1992-93 and 2000-03. Psychological stress was rated according to a standardized question in 1968, 1974 and 1980. Dementia was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders criteria based on information from neuropsychiatric examinations, informant interviews, hospital records and registry data. During the 35-year follow-up, 161 females developed dementia (105 Alzheimer's disease, 40 vascular dementia and 16 other dementias). We found that the risk of dementia (hazard ratios, 95% confidence intervals) was increased in females reporting frequent/constant stress in 1968 (1.60, 1.10-2.34), in 1974 (1.65, 1.12-2.41) and in 1980 (1.60, 1.01-2.52). Frequent/constant stress reported in 1968 and 1974 was associated with Alzheimer's disease. Reporting stress at one, two or three examinations was related to a sequentially higher dementia risk. Compared to females reporting no stress, hazard ratios (95% confidence intervals) for incident dementia were 1.10 (0.71-1.71) for females reporting frequent/constant stress at one examination, 1.73 (1.01-2.95) for those reporting stress at two examinations and 2.51 (1.33-4.77) at three examinations. To conclude, we found an association between psychological stress in middle-aged women and development of dementia, especially Alzheimer's disease. More studies are needed to confirm our findings and to study potential neurobiological mechanisms of these associations.

Amphetamine toxicities: classical and emerging mechanisms

The drugs of abuse, methamphetamine and MDMA, produce long-term decreases in markers of biogenic amine neurotransmission. These decreases have been traditionally linked to nerve terminals and are evident in a variety of species, including rodents, nonhuman primates, and humans. Recent studies indicate that the damage produced by these drugs may be more widespread than originally believed. Changes indicative of damage to cell bodies of biogenic and nonbiogenic amine-containing neurons in several brain areas and endothelial cells that make up the blood-brain barrier have been reported. The processes that mediate this damage involve not only oxidative stress but also include excitotoxic mechanisms, neuroinflammation, the ubiquitin proteasome system, as well as mitochondrial and neurotrophic factor dysfunction. These mechanisms also underlie the toxicity associated with chronic stress and human immunodeficiency virus (HIV) infection, both of which have been shown to augment the toxicity to methamphetamine. Overall, multiple mechanisms are involved and interact to promote neurotoxicity to methamphetamine and MDMA. Moreover, the high coincidence of substituted amphetamine abuse by humans with HIV and/or chronic stress exposure suggests a potential enhanced vulnerability of these individuals to the neurotoxic actions of the amphetamines.

Comorbidity between epilepsy and depression: role of hippocampal interleukin-1beta

Depression is a frequent comorbidity of temporal lobe epilepsy (TLE); however, its mechanisms remain poorly understood and effective therapies are lacking. Augmentation of hippocampal interleukin-1beta (IL-1beta) signaling may be a mechanistic factor of both TLE and clinical depression. We examined whether pharmacological blockade of hippocampal interleukin-1 receptor exerts antidepressant effects in an animal model of comorbidity between TLE and depression, which developed in Wistar rats following pilocarpine status epilepticus (SE). In post-SE animals, depression-like state was characterized by behavioral equivalents of anhedonia and despair; dysregulation of the hypothalamo-pituitary-adrenocortical axis; compromised raphe-hippocampal serotonergic transmission. Two-week long bilateral intrahippocampal infusion of human recombinant Interleukin-1 receptor antagonist (IL-1ra) improved all of the examined depressive impairments, without modifying spontaneous seizure frequency and without affecting normal parameters in naïve rats. These findings implicate hippocampal IL-1beta in epilepsy-associated depression and provide a rationale for the introduction of IL-1beta blockers in the treatment of depression in TLE.

Muscle sympathetic nervous activity in depressed patients before and after treatment with sertraline

BACKGROUND

Sympathetic hyperactivity is one of the mechanisms involved in the increased cardiovascular risk associated with depression, and there is evidence that antidepressants decrease sympathetic activity.

OBJECTIVES

We tested the following two hypotheses: patients with major depressive disorder with high scores of depressive symptoms (HMDD) have augmented muscle sympathetic nervous system activity (MSNA) at rest and during mental stress compared with patients with major depressive disorder with low scores of depressive symptoms (LMDD) and controls; sertraline decreases MSNA in depressed patients.

METHODS

Ten HMDD, nine LMDD and 11 body weight-matched controls were studied. MSNA was directly measured from the peroneal nerve using microneurography for 3 min at rest and 4 min during the Stroop color word test. For the LMDD and HMDD groups, the tests were repeated after treatment with sertraline (103.3 +/- 40 mg).

RESULTS

Resting MSNA was significantly higher in the HMDD [29.1 bursts/min (SE 2.9)] compared with LMDD [19.9 (1.6)] and controls [22.2 (2.0)] groups (P = 0.026 and 0.046, respectively). There was a significant positive correlation between resting MSNA and severity of depression. MSNA increased significantly and similarly during stress in all the studied groups. Sertraline significantly decreased resting MSNA in the LMDD group and MSNA during mental stress in LMDD and HMDD groups. Sertraline significantly decreased resting heart rate and heart rate response to mental stress in the HMDD group.

CONCLUSION

Moderate-to-severe depression is associated with increased MSNA. Sertraline treatment reduces MSNA at rest and during mental challenge in depressed patients, which may have prognostic implications in this group.

Effects of environmental change on wildlife health

Environmental change has negatively affected most biological systems on our planet and is becoming of increasing concern for the well-being and survival of many species. At an organism level, effects encompass not only endocrine disruptions, sex-ratio changes and decreased reproductive parameters, but also include teratogenic and genotoxic effects, immunosuppression and other immune-system impairments that can lead directly to disease or increase the risk of acquiring disease. Living organisms will strive to maintain health by recognizing and resolving abnormal situations, such as the presence of invading microorganisms or harmful peptides, abnormal cell replication and deleterious mutations. However, fast-paced environmental changes may pose additional pressure on immunocompetence and health maintenance, which may seriously impact population viability and persistence. Here, we outline the importance of a functional immune system for survival and examine the effects that exposure to a rapidly changing environment might exert on immunocompetence. We then address the various levels at which anthropogenic environmental change might affect wildlife health and identify potential deficits in reproductive parameters that might arise owing to new immune challenges in the context of a rapidly changing environment. Throughout the paper, a series of examples and case studies are used to illustrate the impact of environmental change on wildlife health.

Altered hepatic mRNA expression of immune response and apoptosis-associated genes after acute and chronic psychological stress in mice

Using a combination of transcriptional profiling and Ingenuity Pathway Analysis (IPA, www.ingenuity.com) we investigated acute and chronic psychological stress induced alterations of hepatic gene expression of BALB/c mice. Already after a 2-h single stress session, up-regulation of several LPS and glucocorticoid-sensitive immune response genes and markers related to oxidative stress and apoptotic processes were observed. Support for the existence of oxidative stress was gained by measuring increased protein carbonylation, but no alterations of immune responsiveness or cell death were measured in mice after acute stress compared to the control group. When animals were repeatedly stressed during 4.5-days, we found reduced transcription of antigen presentation molecules, altered mRNA levels of immune cell signaling mediators and persisting high expression of apoptosis-related genes. These alterations were associated with a measurable immune suppression characterized by a reduced ability to clear experimental Salmonella typhimurium infection from the liver and a heightened hepatocyte apoptosis. Moreover, genes associated with anti-oxidative functions and regenerative processes were induced in the hepatic tissue of chronically stressed mice. These findings indicate that modulation of the immune response and of apoptosis-related genes is initiated already during a single acute stress exposure. However, immune suppression will only manifest in repeatedly stressed mice which additionally show induction of protective and liver regenerative genes to prevent further hepatocyte damage.

Melatonin as a potential therapeutic agent in psychiatric illness

The aim of this review was to summarize the potential use of melatonin in the treatment of mental disorders, specifically bipolar disorders, depression, and schizophrenia. To date, melatonin has been most commonly used in psychiatry because of its hypnotic, rhythm resynchronizing, and antioxidant actions. Here, we examine other properties of the melatonin including its anti-inflammatory, antinociceptive, anxiolytic, and drug detoxification actions as well as its protective effects against neural loss. The brain is an intricate sensory and motor organ which receives information from both the external and internal environments. It transduces information into complex chemical and electrical signals which are transmitted throughout the central nervous system (CNS) and the organism. The pathogenesis of mental disorders remains ambiguous and neuroinflammation has been proposed as a causative agent. We consider the potential contributions of melatonin as therapeutic agent in CNS and during neuroinflammation in mental disorders.

Preliminary evidence of a genetic association between tumor necrosis factor alpha and the severity of sleep disturbance and morning fatigue

Although fatigue and sleep disturbance are prevalent symptoms in oncology patients and their family caregivers, little is known about the factors that contribute to interindividual variability in symptom severity ratings as well as in their underlying biological mechanisms. In this study, we sought to determine whether a functional genetic variation in a prominent proinflammatory cytokine, tumor necrosis factor-alpha (TNFA-308G>A [rs1800629] promoter polymorphism) was associated with overall ratings of sleep disturbance and fatigue as well as with the trajectories of these symptoms. Over 6 months, participants completed standardized measures of sleep disturbance and fatigue. Multiple linear regression was used to assess the effect of the TNFA genotype and other covariates on mean sleep disturbance and fatigue scores. Hierarchical linear modeling was used to determine the effect of TNFA genotype on the trajectories of these symptoms. Common allele homozygotes reported higher levels of sleep disturbance (p=.09) and morning fatigue (p=.02) than minor allele carriers. Multivariate analyses demonstrated that age and genotype were predictors of both mean symptom scores and the trajectories of these symptoms. Findings provide preliminary evidence of an association between a functional promoter polymorphism in the TNFA gene and the severity of sleep disturbance and morning fatigue in oncology patients and their family caregivers.

Taurine transporter in lymphocytes of patients with major depression treated with venlafaxine plus psychotherapy

The taurine transporter and taurine are present in lymphocytes, where taurine functions as an antioxidant and an anti-inflammatory agent. Taurine levels are elevated in lymphocytes of subjects with major depression, but returns to control levels after treatment with the antidepressant mirtazapine. Patients (40) were diagnosed using the Diagnostic and Statistical Manual IV of the American Psychiatric Association, and the severity of their condition was determined by the Hamilton Scale of Depression. One group of patients was treated with venlafaxine and the other with venlafaxine plus Neuro-Linguistic Programming. Lymphocytes were isolated from the peripheral blood by Ficoll/Hypaque. The coexistence of the taurine transporter with a subpopulation of CD4+ and CD8+ lymphocytes was measured by immunofluorescence. The levels of the pro-inflammatory, IL-2, and the anti-inflammatory, IL-4, cytokines were determined by ELISA while plasma amino acid levels were determined by HPLC. The percentage of CD4+ cells significantly decreased after both treatments, whereas the levels of CD8+ cells remained unchanged. The taurine transporter of CD4+ and CD8+ cells decreased after integrate treatment. No differences were found in the levels of IL-2 while IL-4 levels increased after integrate treatment. The observed effects of treatment on the taurine transporter and IL-4 content might modify lymphocyte activity during depression.

Chronic fatigue syndrome and the central nervous system

An increasing amount of neuroimaging evidence supports the hypothesis that chronic fatigue syndrome patients have structural or functional abnormalities within the brain. Moreover, some neurotrophic factors, neurotransmitters and cytokines have also been evaluated in order to elucidate the mechanism of abnormal neuropsychic findings in chronic fatigue syndrome. In this review, we suggest that the focal point of chronic fatigue syndrome research should be transferred to the central nervous system.