Association study between the novel functional polymorphism of the serotonin transporter gene and suicidal behaviour in schizophrenia.

A serotonin transporter gene linked polymorphic region (5-HTTLPR) has been investigated in several genetic association studies, including studies of schizophrenia and suicidality. The current study was designed to examine whether the new long (A/G) variant polymorphism of the 5-HTT gene may be associated with suicide attempts of 290 Caucasian schizophrenic patients. Among these patients, 92 had a history of suicide attempt. No association with history of suicide attempt was found in the multiallelic 5-HTTLPR (p = 0.305), however we found significant association with the intron 2 VNTR polymorphism (p = 0.018). When we performed a haplotype analysis, we found association between suicide attempt and haplotype distribution (p = 0.031). These findings suggest that the intron 2 VNTR polymorphism in serotonin transporter gene may influence suicidal behaviour in schizophrenia.     

HPA axis and cytokines dysregulation in schizophrenia: potential implications for the antipsychotic treatment

The authors discuss literature evidence on the possible dysfunctioning of HPA axis and the inflammatory response system (IRS) in schizophrenia in relation to a more comprehensive bio-pathogenetic hypothesis of the disorder and to the development of specific clinical patterns or ‘core’ schizophrenic symptoms, like those included in the so called negative/depressive dimension. The dysfunctions of HPA axis and IRS could be linked to some neurodevelopmental damage in relevant brain areas like hippocampus and it could involve mainly the glutamatergic pathways (e.g. NMDA receptors). Moreover, these changes could have some predictive value for response to typical antipsychotics (specifically for negative symptoms and drug resistance) in schizophrenia. Finally, the differential activity of typical versus atypical antipsychotic compounds on the basic HPA axis and IRS dysregulations in schizophrenia could account, at least partly, for the better clinical stabilization achieved in patients treated with the latter drugs compared to those receiving conventional neuroleptics.     

Polymorphisms in genes regulating the HPA axis associated with empirically delineated classes of unexplained chronic fatigue

Chronic fatigue syndrome (CFS) is characterized by persistent or relapsing fatigue that is not alleviated by rest, causes substantial reduction in activities and is accompanied by a variety of symptoms. Its unknown etiology may reflect that CFS is heterogeneous. Latent class analyses of symptoms and physiological systems were used to delineate subgroups within a population-based sample of fatigued and nonfatigued subjects [1] . This study examined whether genetic differences underlie the individual subgroups of the latent class solution. Polymorphisms in 11 candidate genes related to both hypothalamic-pituitary-adrenal (HPA) axis function and mood-related neurotransmitter systems were evaluated by comparing each of the five ill classes (Class 1, n = 33; Class 3, n = 22; Class 4, n = 22; Class 5, n = 17; Class 6, n = 11) of fatigued subjects with subjects defined as well (Class 2, n = 35). Of the five classes of subjects with unexplained fatigue, three classes were distinguished by gene polymorphsims involved in either HPA axis function or neurotransmitter systems, including proopiomelanocortin (POMC), nuclear receptor subfamily 3, group C, member 1 (NR3C1), monoamine oxidase A (MAOA), monoamine oxidase B (MAOB), and tryptophan hydroxylase 2 (TPH2). These data support the hypothesis that medically unexplained chronic fatigue is heterogeneous and presents preliminary evidence of the genetic mechanisms underlying some of the putative conditions.     

HPA axis and cytokines dysregulation in schizophrenia: potential implications for the antipsychotic treatment.

The authors discuss literature evidence on the possible dysfunctioning of HPA axis and the inflammatory response system (IRS) in schizophrenia in relation to a more comprehensive bio-pathogenetic hypothesis of the disorder and to the development of specific clinical patterns or 'core' schizophrenic symptoms, like those included in the so called negative/depressive dimension. The dysfunctions of HPA axis and IRS could be linked to some neurodevelopmental damage in relevant brain areas like hippocampus and it could involve mainly the glutamatergic pathways (e.g. NMDA receptors). Moreover, these changes could have some predictive value for response to typical antipsychotics (specifically for negative symptoms and drug resistance) in schizophrenia. Finally, the differential activity of typical versus atypical antipsychotic compounds on the basic HPA axis and IRS dysregulations in schizophrenia could account, at least partly, for the better clinical stabilization achieved in patients treated with the latter drugs compared to those receiving conventional neuroleptics.     

CO2 challenge induced HPA axis activation in panic

The hypothalamic-pituitary-adrenal axis (HPA axis) plays a critical role in stress management. Involvement of this physiological axis in the underlying mechanisms of panic disorder (PD) has been suggested. Studies using 35% CO(2) inhalation to provoke panic found no evidence for robust increases in cortisol levels in PD. However, cortisol levels alone may not be conclusive, as this hormone is merely the end product of a complex physiological axis. Sixteen PD patients and 16 healthy control subjects underwent a 35% CO(2) inhalation and a placebo inhalation on separate days according to a fixed order, double-blind design. Both serum and salivary cortisol, as well as adrenocorticotropic hormone (ACTH) were measured at regular time intervals. Cortisol and ACTH levels increased in the patient and control groups following 35% CO(2) inhalation. The magnitude of the increase was similar in patients and controls despite marked differences in anxiety. This study is the first to document a clear HPA response following 35% CO(2) inhalation in both PD patients and controls. This effect occurs independently of the specific panicogenic properties of the CO(2) challenge. It remains to be clarified whether panic is initially accompanied by major HPA axis activation or whether other stress-responsive systems underlie panic.     

Allopregnanolone modulation of HPA axis function in the adult rat

Rationale

GABAergic neuronal circuits regulate neuroendocrine stress response, and the most potent positive endogenous modulator of GABA_A receptor function is allopregnanolone. This neurosteroid acts in a nongenomic manner to selectively increase the inhibitory signal meditated by GABA_A receptors; in addition, it also induces long-lasting changes in the expression of specific GABA_A receptor subunits in various brain regions, with consequent changes in receptor function.

Objective

The objective of this review is to summarize our findings on emotional state and stress responsiveness in three animal models in which basal brain concentrations of allopregnanolone differ. It is postulated that individual differences in allopregnanolone levels can influence general resilience.

Results

The results showed that there is an apparent correlation between endogenous levels of brain allopregnanolone and basal and stress-stimulated HPA axis activity.

Conclusion

The relationship between endogenous brain levels of allopregnanolone and HPA axis activity and function sustains the therapeutic potential of this neurosteroid for the treatment of stress-associated disorders.     

Identification of suicidal ideation and prevention of suicidal behaviour in the elderly

In almost all industrialised countries, men aged 75 years and older have the highest suicide rate among all age groups. Although in younger age groups suicide attempts are often impulsive and communicative acts, suicide attempts in older people (defined as aged 65 years and older) are often long planned and involve high-lethality methods. These characteristics, in addition to the fact that elderly are more fragile and frequently live alone, more often lead to fatal outcome. In later life, in both sexes, the most common diagnosis in those who attempt or complete suicide is major depression. In contrast to other age groups, comorbidity with substance abuse and personality disorders is less frequent. Physical illness plays an important role in the suicidal behaviour of the elderly: most frequently, depression and illness co-occur; less often, the physical illness or the treating medications are causally related to the depressive symptoms. However, only 2 to 4% of terminally ill elderly commit suicide. In addition to physical illness, complicated or traumatic grief, anxiety, unremitting hopelessness after recovery from a depressive episode and history of previous suicide attempts are risk factors for suicide attempts and completed suicide. During a depressive episode, elderly patients with suicidal ideation have higher levels of anxiety and, during treatment, anxiety decreases the probability of remission and recovery. As well as overt suicide attempts, indirect self-destructive behaviours, which often lead to premature death, are common, especially in residents of nursing homes, where more immediate means to commit suicide are restricted. Although we do not have randomised trials of treatment, studies suggest that antidepressant treatment may decrease suicide risk. Prevention and treatment trials are underway to detect the effectiveness of improved treatment of depression by primary care physicians as a means of reducing the prevalence of depressive symptoms, hopelessness and suicidal ideation.     

Correlates of impulsive suicidal behaviour.

Up to two-thirds of reported suicidal acts are impulsive in nature. In a series of patients presenting at a general hospital as a result of suicidal behaviour, it was concluded that over half the acts were impulsive in nature. A number of variables were found to be related to the occurrence of impulsive suicidal behaviour and they included the following: a past history of suicidal behaviour, the tablets being in the same room when the decision to engage in the act was reached, the ingestion of more than half the available tablets, and finally, the tablets tending to be bottled rather than foil packaged. Findings were discussed in terms of the aetiology and prevention of impulsive suicidal behaviour.     

The HPA axis in cocaine use: implications for pharmacotherapy.

The role of the hypothalamic-pituitary-adrenal (HPA) axis in cocaine use is reviewed within the context of two approaches to developing pharmacological treatments in humans: (1) reducing the reinforcing effects of cocaine and (2) reducing cocaine addict's susceptibility to stress-induced relapse. This review suggests that HPA-axis-suppressing medications are unlikely to block cocaine's reinforcing effects completely but may be useful in decreasing the frequency of use by increasing the addicted individual's resistance to stress-induced relapse. Implications for designing inpatient studies to test the safety and efficacy of candidate pharmacological agents are discussed.     

Interaction of 5-HT and HPA axis in depression and treatment-resistant depression

Psychoendocrinology studies of depressed patients focus on the disregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Abnormalities in the HPA axis have been noted in depressed patients. Numerous data have demonstrated the existence of reciprocal interactions between the central serotonin (5-HT) system and HPA axis. These interactions are of particular relevance when considering pathological conditions, such as depression, in which modifications of both the 5-HT system and HPA axis have been evidenced. In our laboratory, we examined the effects of adrenocorticotropic hormone (ACTH) on the immobilization of rats in the forced swim test and on the wet-dog shakes induced by the DOI, 5-HT2 receptor agonist with the administration of imipramine and lithium. The reduction of immobility, induced by the chronic administration of imipramine for 15 days, was blocked by treatment with ACTH for 14 days. And, chronic ACTH treatment for 14 days increased the wet-dog shake response. This effect of ACTH was not inhibited by a 14-day administration of imipramine. Accordingly, the chronic treatment of rats with ACTH may prove to be an effective model for antidepressant-treatment-resistant depression. We believe that behavioral pharmacological and molecular biological research into the interaction between the 5-HT and HPA axis will elucidate the pathogenesis of depression or antidepressant-treatment-resistant depression and the mechanism of antidepressants action.     

Association study of a novel functional polymorphism of the serotonin transporter gene in bipolar disorder and suicidal behaviour

A serotonin transporter gene linked polymorphic region (5-HTTLPR) has been investigated in several genetic association studies, including studies of bipolar disorder (BD) and suicidality. The current study was designed to examine whether the new long (A/G) variant polymorphism of the 5-HTT gene may be associated with the suicide attempts in 305 families with at least one member having BD. No association with history of suicide attempt was found either in the multiallelic HTTLPR (LRS=0.15, df=2, P=0.92), or with the intron 2 variable number tandem repeat (VNTR) polymorphism (LRS=0.87 df=2 P=0.64). When we performed a haplotype analysis, we found no association between suicide attempt and haplotype distribution (LRS=1.84 df=4 P=0.76). These findings suggest that this new polymorphism in the 5-HTT gene may not influence suicidal behaviour in patients with bipolar disorder.     

Basal activity of the HPA axis and cognitive function in anorexia nervosa

Elevated cortisol and cognitive impairments have been described in anorexia nervosa, but the relationship between these two variables has not been adequately explored. We profiled the pattern and extent of the cognitive impairment in anorexia nervosa and determined how this related to cortisol secretion. Twenty patients with anorexia nervosa and a matched control group completed a computerized cognitive assessment battery. Diurnal cortisol secretion was measured by serial saliva sampling. Patients were significantly impaired on tasks of attention, long-term memory and working memory. Both groups showed the expected diurnal variation in cortisol production, but no evidence was found for patient cortisol hypersecretion. No correlation was found between cortisol secretion and any of the cognitive task measures. These data suggest that at least some of the cognitive impairments seen in anorexia nervosa are attributable to something other than a basal increase in cortisol secretion. The limitations of cortisol as an indicator of HPA axis activity are discussed.     

HPA轴功能紊乱干预药物的研究进展

目的对近年来基于下丘脑-垂体-肾上腺（hypothalamic-pituitary-adrenal ,HPA）轴功能调节治疗2型糖尿病和其他代谢疾病的药物做以综述,为H PA轴功能紊乱引起的相关疾病的治疗提供理论参考。方法查阅国内外文献,分析、总结 H PA轴功能紊乱干预药物的研究现状和研究前景。结果 HPA轴功能紊乱,尤其是 HPA轴功能亢进在2型糖尿病、抑郁症等疾病的发病过程中发挥重要作用;目前有以下几类通过作用于HPA轴不同靶点调节HPA轴功能的药物,即11β-HSD1抑制剂、糖皮质激素受体拮抗剂、多巴胺受体拮抗剂和选择性5-H T再摄取抑制剂等,具体机制还有待进一步阐明。结论通过调节H PA轴活性有可能达到预防和治疗2型糖尿病及其他相关疾病的目的。     

Therapeutic implications of HPA axis abnormalities in Alzheimer's disease: review and update

The adaptive and maladaptive roles of the hypothalamic-pituitary-adrenal (HPA) axis in stressful conditions and in disorders such as major depression, posttraumatic stress disorder, and Cushing's syndrome, have been the subject of substantial, ongoing study. In particular, HPA disturbances have been associated with memory impairments, and hypercortisolemic conditions with atrophy of the hippocampus, a limbic structure closely associated with declarative memory. Recent discoveries support a more complicated picture of HPA axis function and pathology in acquiring, retrieving, and consolidating new memories. These findings include: the existence of an 'inverted U-shaped relationship" between stimulation of brain glucocorticoid receptors and memory performance; that distinct areas of the hippocampus have been found to respond differently to cortisol stimulation; and that hippocampal atrophy has been found to be potentially reversible in some conditions, although whether such atrophy is a cause or effect of these pathological conditions is currently unclear. More longitudinal studies of HPA axis function in aging normal individuals, those with mild cognitive impairment,and individuals with Alzheimer' disease, examining pertinent variables such as APOEe-4 status, are needed to help clarify these new findings. Antiglucocorticoid agents appear to have therapeutic value in particular conditions. These results are relevant for understanding and treating memory dysfunction in individuals with Alzheimer's disease, a disorder prominently and invariably characterized by early hippocampal lesions and memory impairment. Given the burden of this disease, we feel it timely to encourage controlled trials of antiglucocorticoid agents in the treatment of mild cognitive impairment and Alzheimers disease.     

Flavonoids of St. John's Wort reduce HPA axis function in the rat

A common biological alteration in patients with major depression is the activation of the hypothalamic-pituitary-adrenal (HPA) axis, manifested as hypersecretion of adrenocorticotropic hormone (ACTH) and cortisol. The hyperactivity of the HPA axis in depressed patients can be corrected during clinically effective therapy with standard antidepressant drugs such as imipramine, indicating that the HPA axis may be an important target for antidepressant action. We previously showed that a methanolic extract of St. John's Wort (SJW) and hypericin, one of its active constituents, both have delayed effects on the expression of genes that are involved in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis , whereas the phloroglucinol derivative hyperforin was inactive in the same model . Since flavonoids of SJW are also discussed as active constituents it was of interest to determine whether these compounds can modulate HPA axis function. Imipramine (15 mg/kg), hypericin (0.2 mg/kg), hyperoside (0.6 mg/kg), isoquercitrin (0.6 mg/kg) and miquelianin (0.6 mg/kg) given daily by gavage for two weeks significantly down-regulated circulating plasma levels of ACTH and corticosterone by 40 - 70 %. However, none of the compounds tested had an effect on plasma ACTH and corticosterone levels after chronic treatment (daily gavage for 8 weeks). Our data suggest that besides hypericin, flavonoids of SJW play an important role in the modulation of HPA axis function. Furthermore, the results support the hypothesis that flavonoids are involved in the antidepressant effects of SJW.     

Influence of chronic stress on brain corticosteroid receptors and HPA axis activity

BackgroundDisruption of the glucocorticoid negative feedback system evoked in animals by chronic stress can be induced by downregulation of glucocorticoid receptors (GRs) in several brain regions. In the present study, the dynamics of the changes in GRs, in brain structures involved in stress reactions, prefrontal cortex, hippocampus and hypothalamus was compared with the peripheral hypothalamo-pituitary-adrenocortical (HPA) axis hormones response to chronic stress.MethodsRats were exposed to 10 min restraint or restrained twice a day for 3, 7 or 14 days, and 24 h after the last stress session exposed to homotypic stress for 10 min. Control rats were not restrained. After rapid decapitation at 0, 1, 2, and 3 h after stress termination, trunk blood for plasma adrenocorticotropic hormone (ACTH) and corticosterone determinations was collected and prefrontal cortex, hippocampus and hypothalamus were excised and frozen. Plasma hormones were determined using commercially available kits and glucocorticoids and mineralocorticoids protein levels in brain structure samples were determined by western blot procedure.ResultsRestraint stress alone significantly decreased glucocorticoid receptor (GR) level in prefrontal cortex and hippocampus, and increased mineralocorticoid receptor (MR) level in hypothalamus. Prior repeated stress for 3 days significantly increased GR protein level in hippocampus and diminished that level in hypothalamus in 7 days stressed rats. Acute stress-induced strong increase in plasma ACTH and corticosterone levels decreased to control level after 1 or 2 h, respectively. Prior repeated stress for 3 days markedly diminished the fall in plasma ACTH level and repeated stress for 7 days moderately deepened this decrease. Plasma ACTH level induced by homotypic stress in rats exposed to restraint for 3, 7, and 14 days did not markedly differ from its control level, whereas plasma corticosterone response was significantly diminished. The fast decrease of stress-induced high plasma ACTH and corticosterone levels was accompanied by a parallel decline of GR level only in prefrontal cortex but not in the hippocampus or hypothalamus.ConclusionsComparison of the dynamics of changes in plasma ACTH and corticosterone level with respective alterations in GR and MR in brain structures suggests that the buffering effect of repeated stress depends on the period of habituation to stress and the brain structure involved in regulation of these stress response.