Natural killer cell activity and csf monoamine metabolites in suicide attempters

Abstract

The aim of this study was to investigate markers of serotonin and immune function in suicidal patients. Cytotoxic activity of natural killer cells (NK) and CD16 lymphocytes were studied in 28 suicide attempters and 26 healthy controls, and related in patients to 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF). Patients with CSF 5-HIAA below the median had significantly lower NK cell activity than other patients. CD 16 cell frequency was significantly lower in patients than in controls, and patients also tended to have lower NK cell cytotoxicity than healthy controls. There were no statistically significant correlations between 4-hydroxy-3methoxyphenyl glycol (HMPG), homovanillic acid (HVA), CSF cortisol and NK cell activity. The results support the hypothesis of compromised immune function in suicidal patients with evidence of disordered serotonin function.     

Concentration gradients for monoamine metabolites in lumbar cerebrospinal fluid

Summary Concentration gradients in lumbar cerebrospinal fluid (CSF) for the monoamine metabolites homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA) and 4-hydroxy-3-methoxyphenylglycol (HMPG) were studied in 9 healthy controls and 47 neuropsychiatric patients without diseases causing disturbed CSF circulation. In a serial sampling of the first 24 ml of CSF, steep concentration gradients between the first (0–4 th ml) and last (21th–24th ml) portions of CSF were found for HVA (99±59% increase; p<0.001) and 5-HIAA (88±54% increase; p<0.001), while the concentration gradient was slight for HMPG (11±7% increase; p<0.001). The existence of marked concentration gradients for the monoamine metabolites HVA and 5-HIAA gives further evidence for an active transport system for these metabolites and indicates that the lumbar CSF-HVA and 5-HIAA levels reflect the dopamine and serotonin metabolism in the brain. Moreover, the existence of pronounced concentration gradients for HVA and 5-HIAA levels reflect the dopamine and serotonin metabolism in the brain. Moreover, the existence of pronounced concentration gradients for HVA and 5-HIAA stresses the importance of making analyses on a standardized volume of CSF.     

Natural killer (Nk) Cell activity and nk cell subsets in workers with a tendency of burnout

The involvement of cellular immunity in the burnout syndrome remains to be elucidated. We assessed three components of burnout of the Maslach Burnout Inventory: emotional exhaustion; depersonalization (DP); and personal accomplishment, as well as natural killer cell activity (NKCA) and NK cell subsets in 42 male workers. Workers with a higher DP score showed a lower NKCA and a lower proportionality of CD57⁺CD16⁺ to total lymphocytes. There were no differences in any of the health behaviors (e.g., smoking, alcohol, or obesity) between workers showing higher burnout and those showing lower burnout. A stepwise multiple regressions analysis demonstrated that NKCA was closely correlated with DP, independent of other variables, including a stress index. These results suggest that the relationship between reduced cellular immunity and DP is not due to traditional work stress or health behavioral problems. Further studies on DP as a psychosomatic disorder as well as an occupational health problem should be performed in the future.     

Brain ventricular size and CSF monoamine metabolites in an adolescent inpatient population

The cerebrospinal fluid monoamine metabolites, homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA), were compared with ventricle-brain ratios (VBRs) in a group of adolescent inpatients who were divided into psychotic and nonpsychotic groups. HVA, 5HIAA, and VBR did not differ significantly between the two groups. There were no significant relationships between these variables in the nonpsychotic group. Psychotic adolescents, however, displayed significant negative correlations between VBR and HVA, and between VBR and 5HIAA. The relationship between VBR and monoamine metabolites appears to occur in psychoses other than schizophrenia, is present early in the course of illness, and probably does not represent a dilutional effect.     

Platelet MAO activity and monoamine metabolites in cerebrospinal fluid in depressed and suicidal patients and in healthy controls

Platelet monoamine oxidase (MAO) activity and cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacetic acid (5HIAA), homovanillic acid (HVA), and 4-hydroxy-3-methoxyphenylglycol (HMPG) were simultaneously measured in 20 currently depressed patients, 11 recovered depressed patients, 15 nondepressed suicide attempters, and 42 healthy control subjects. Both 5HIAA and HVA were positively and significantly correlated to platelet MAO activity in the healthy subjects, but not in any of the patient groups. Suicide attempters had significantly lower CSF 5HIAA than nonsuicidal patients.     

CSF monoamine metabolites in dementia of the Alzheimer type and controls: Evidence for lower levels of homovanillic acid and 5-hydroxyindoleacetic acid in patients

The monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in lumbar cerebrospinal fluid (CSF) were measured in 15 patients with dementia of the Alzheimer type (DAT) and 48 controls by means of a sensitive liquid chromotagraphic method. Relative to a large group of control subjects, the mean CSF 5-HIAA and HVA levels in patients with DAT appeared to be significantly lower. This finding appeared to be sex-related, in that the decrease in CSF monoamine metabolite levels could be attributed predominantly to male patients. A statistically significant relationship was found between 5-HIAA and HVA in both patients and controls. Linear regression analysis revealed a statistically significant positive relationship between age and CSF HVA in female controls only. No relationship was found between 5-HIAA and age either in patients or in controls. It is concluded that CSF 5-HIAA and HVA levels are decreased in male patients with DAT, probably signalling a sex-related change in serotonin and probably dopamine functioning in the central nervous system.     

A prospective study of the association of cerebrospinal fluid monoamine metabolite levels with lethality of suicide attempts in patients with bipolar disorder

Objectives:  Bipolar disorder is a severe illness that is associated with suicidal behavior. A biological predictor of highly lethal suicide attempts in patients with bipolar disorder would be valuable. We hypothesized that cerebrospinal fluid (CSF) monoamine metabolite levels are related to lethality of suicide attempts in bipolar patients and examined the relation between CSF 5-hydroxyindolacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) levels and maximum lethality of suicide attempts at baseline and during a 2-year follow up.
Methods:  Twenty-seven bipolar depressed patients participated in the study. Demographic and clinical parameters were examined and recorded. Lumbar punctures were performed and CSF 5-HIAA, HVA, and MHPG were assayed by high-performance liquid chromatography with electrochemical detection. Following discharge, patients were evaluated after 3 months, 1 year, and 2 years. Each follow-up interview included an in-depth assessment of suicidal behavior during the intervening time period.
Results:  Six subjects made suicide attempts during the 2-year follow-up. Bipolar patients who attempted suicide during the follow-up period had higher aggression and hostility scale scores compared to bipolar subjects who did not make a suicide attempt during the follow-up period. CSF 5-HIAA, HVA, and MHPG levels were negatively correlated with the maximum lethality of suicide attempts during the 2-year follow-up period.
Conclusions:  Our finding is the first observation that CSF monoamine metabolite levels may be predictors of lethality of suicide attempts in patients with bipolar disorder. Further studies are necessary to answer the question whether CSF monoamine metabolite levels are clinically useful biochemical predictors of highly lethal suicide attempts or completed suicides.     

Uncoupling of serotonergic and noradrenergic systems in depression: Preliminary evidence from continuous cerebrospinal fluid sampling

We used the technique of continuous cerebrospinal fluid (CSF) sampling to test the following hypotheses regarding CNS monoaminergic systems in depression:(1) absolute concentrations of the informational substances tryptophan and 5-hydroxyindoleacetic acid (5-HIAA) are altered in the CNS of depressed patients (2) abnormal rhythms of tryptophan and/or 5-HIAA, or defective conversion of tryptophan to serotonin (5HT), exist in the CNS of depressed patients, and (3) the relationship between the CNS 5HT and norepinephrine (NE) systems is disrupted in depressed patients. We obtained 6-h concentration time series of tryptophan, 5-HIAA, NE, and 3-methoxy-4-hydroxyphenylglycol (MHPG) in the CSF of 10 patients with major depression and in 10 normal volunteers. No significant differences in CSF tryptophan, 5-HIAA, NE, or MHPG concentrations or rhythms were observed between normal volunteers and depressed patients. Neither were there differences in the mean tryptophan-to-serotonin ratio. However, a negative linear relationship was observed between mean concentrations of 5-HIAA and NE in the CSF of the normal volunteers (r = 0.916 [r2 = 0.839], df = 9, P < 0.001) while, in contrast, depressed patients showed no such relationship (r = +0.094 [r2 = 0.00877], df = 9, n.s.). Furthermore, the correlation coefficients expressing the relationship between CSF MHPG and CSF 5-HIAA within the normal and depressed groups were significantly different. These data support the hypothesis that a disturbance in the interaction between the serotonergic and noradrenergic systems can exist in depressive illness in the absence of any simple 5HT or NE deficit or surplus. Depression and Anxiety 6:89–94, 1997.© 1997 Wiley-Liss, Inc.     

Tryptophan hydroxylase and catechol-O-methyltransferase gene polymorphisms: relationships to monoamine metabolite concentrations in CSF of healthy volunteers

Concentrations of monoamine metabolites (MM) in lumbar cerebrospinal fluid (CSF) have been used extensively as indirect estimates of monoamine turnover in the brain. We investigated possible relationships between DNA polymorphisms in the tryptophan hydroxylase (TPH) and catechol-O-methyltransferase (COMT) genes and CSF concentrations of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in healthy volunteers (n = 66). Lower CSF 5-HIAA levels were found in men with the TPH U allele (p = 0.005), but not in women. A similar but less significant pattern was observed for CSF HVA. No relationship was found between the TPH polymorphism and CSF MHPG. COMT genotypes did not relate significantly to MM concentrations. The results suggest that TPH genotypes participate differentially in the regulation of serotonin turnover rate under presumed steady state in the central nervous system of men. Due to the uncertain functional relevance of the DNA polymorphism investigated and the many calculations performed, the results should be interpreted with caution until replicated.     

Low HVA and normal 5HIAA CSF levels in drug-free schizophrenic patients compared to healthy volunteers: correlations to symptomatology and family history

Cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA) were determined in 40 drug-free schizophrenic patients and 21 healthy volunteers by a mass fragmentographic method. Twenty-one of the schizophrenic patients were first admissions who had never received neuroleptics. Significantly, lower levels of HVA but not 5HIAA were found in the patient group, and no difference was found between chronic, previously neuroleptic-treated and never-medicated patients. HVA levels correlated positively with social interest and total positive scores on the Nurses Observation Scale for Inpatient Evaluation (NOSIE-30) and negatively with lassitude and slowness of movements on the Comprehensive Psychopathological Rating Scale (CPRS). Low levels of 5HIAA were correlated to the CPRS items delusions and apparent sadness. There were slightly higher CSF levels of 5HIAA in patients with a family history of schizophrenia, but no such difference was seen for HVA. In both schizophrenic and control subjects CSF levels of HVA and 5HIAA showed a strong intraindividual correlation. The results indicate decreased central nervous system dopaminergic turnover in schizophrenia which seems to be associated with "negative" symptomatology.     

Interferon production and natural killer (NK) activity in leukocyte cultures from multiple sclerosis patients

Peripheral blood leukocyte (PBL) cultures from only 37% of MS patients produced detectable HuIFN-gamma in response to ConA as opposed to 85% of the cultures derived from normal blood donors. However, the yields in patient-derived cultures that were responsive, were not lower than those in cultures from controls. Production of HuIFN-alpha after stimulation with Sendai virus was not aberrant in cells taken from MS patients. The difference in HuIFN-gamma response rate between MS and normal donor-derived cells was more pronounced when DR2+ carriers were compared amongst each other than when DR2-k carriers were compared. Among the MS patients, the failure of PBLs to produce HuIFN-gamma in response to ConA was not correlated with age, sex, disease duration and type of disease. However, positive correlations were found with current disability indices and past disease progression rates. Unstimulated NK-activities of MS patient-derived PBLs were not different from those of normal donor-derived cells. the degree of augmentation of the activity by stimulation with ConA and interferon-alpha was also normal. Within the MS patients group, but not in the control group, there was a trend for DR2+ carriers to have lower spontaneous and stimulated NK-activities than DR2- individuals.     

Leukocyte glutamate dehydrogenase and CSF amino acids in late onset ataxias

Leukocyte glutamate dehydrogenase (GDH) activity was measured in 11 healthy control subjects, 16 neurological controls, 12 patients with dominant late onset ataxia, 15 patients with sporadic late onset ataxia and 8 with alcoholic cerebellar ataxia. Serum hexosaminidase activity was also determined in ataxic patients. Concentrations of free amino acids were determined in the lumbal CSF of 16 neurological controls, 8 patients with late onset ataxia and 5 with alcoholic ataxia. Mean total GDH activity was reduced significantly in dominant (p less than 0.05) and sporadic (p less than 0.01) cerebellar ataxia, while the heat-labile form was decreased significantly (p less than 0.01) only in sporadic ataxia. All GDH activities were within normal range in patients with alcoholic ataxia. The serum hexosaminidase activities were also within reference range in all patient groups. The CSF concentrations of alanine, glycine, methionine and valine were significantly elevated and those of GABA and glutamate were normal in patients with late onset ataxia as compared to neurological controls. The most significant (p less than 0.01) increase was found for methionine. The amino acid levels of patients with alcoholic ataxia did not differ from those of the controls. The results suggest that GDH activity is only partially decreased in some ataxic patients and that altered amino acid metabolism may be reflected in the CSF.     

Leukocyte glutamate dehydrogenase and CSF amino acids in late onset ataxias

Leukocyte glutamate dehydrogenase (GDH) activity was measured in 11 healthy control subjects, 16 neurological controls, 12 patients with dominant late onset ataxia, 15 with sporadic late onset ataxia and 8 with alcoholic cerebellar ataxia. Serum hexosaminidase activity was also determined in ataxic patients. Concentrations of free amino acids were determined in the lumbal CSF of 16 neurological controls, 8 patients with late onset ataxia and 5 with alcoholic ataxia. Mean total GDH activity was reduced significantly in dominant (p less than 0.05) and sporadic (p less than 0.01) cerebellar ataxia, while the heat-labile form was decreased significantly (p less than 0.01) only in sporadic ataxia. All GDH activities were within normal range in patients with alcoholic ataxia. The serum hexosaminidase activities were also within reference range in all patient groups. The CSF concentrations of alanine, glycine, methionine and valine were significantly elevated and those of GABA and glutamate were normal in patients with late onset ataxia as compared to neurological controls. The most significant (p less than 0.01) increase was found for methionine. The amino acid levels of patients with alcoholic ataxia did not differ from those of the controls. The results suggest that GDH activity is only partially decreased in some ataxic patients and that altered amino acid metabolism may be reflected in the CSF.     

Cerebrospinal fluid cholecystokinin, bombesin and somatostatin in schizophrenia and normals

Cerebrospinal fluid from 31 normals and two groups of phenomenologically similar schizophrenics (n = 72) were collected by identical methods. Radioimmunoassay of CSF was carried out for somatostatin, bombesin, and cholecystokinin. One group of schizophrenics had increased baseline somatostatin and cholecystokinin, and decreased bombesin. No CSF gradient effect was found for the peptides nor were their levels affected by probenecid or pimozide treatment. An inverse correlation was found between bombesin and psychosis rating. Intercorrelation between the peptides and HVA, 5-HIAA, and MHPG were not significant.     

Natural killer cell cytotoxicity and lymphocyte perforin expression in veterans with posttraumatic stress disorder

Objective

To examine the effect of posttraumatic stress disorder (PTSD) on the measures of immune function and the hypothalamic–pituitary–adrenal axis components, and to determine whether additional life stressors affect measured variables.

Methods

We simultaneously examined the natural killer cell cytotoxicity (NKCC), perforin and glucocorticoid receptor (GCR) expression in natural killer (NK) and cytotoxic T (CD8) cells, as well as serum cortisol concentration in a group of Croatian war veterans with chronic, combat-related PTSD (n = 29) and a group of healthy, age-matched men (n = 13). PTSD patients were divided into two subgroups: compensation-seeking (n = 15) and retired or compensation non-seeking (n = 14) subjects. The former includes those involved in the process of getting disability-based army retirement as an additional life stressor.

Results

NKCC was decreased in both PTSD groups when compared to controls. Impairment of NKCC could not be attributed to the perforin expression as perforin was not decreased in comparison to controls. Moreover, the increased level of perforin was recorded in NK cells of retired PTSD subjects. Both PTSD groups shared an increased relative quantity of GCR in lymphocytes, whereas no difference between the groups in the baseline levels of serum cortisol was observed.

Conclusions

Diminished NKCC was not accompanied by perforin insufficiency in PTSD subjects, and other causes should be examined. An additional life stressor does not contribute considerably to either immune or endocrine system related changes.     

Biological correlates of attachment bond disruption in humans and nonhuman primates

Separations or disruptions in attachment bonds occur frequently in the social lives of humans and have been linked to the development of psychopathology. Separation of social nonhuman primates has been proposed as a model to study the psychological and biological effects of separation in humans. This paper reviews the biological alterations that occur in nonhuman primates undergoing separation and compares these with changes associated with separation in humans. The data reviewed demonstrate that separation in humans and nonhuman primates can be an event with profound behavioral and physiological sequelae.     

Regulation of natural killer cell cytotoxicity by prostaglandin E in the peripheral blood and cerebrospinal fluid of patients with multiple sclerosis and other neurological diseases part 2. Effect of Exogenous PGE1 on spontaneous and interferon-induced natural killer

Compared to normal and other neurological disease (OND) controls, multiple sclerosis (MS) pre nylon wool (pre NW) and nylon wool passed (NWP)-peripheral blood cells' natural killer (NK) activity was more sensitive to prostaglandin E (PGE1); it was suppressed to a greater degree and at lower concentrations of PGE1. At the single cell level this was reflected by lower numbers of target-binding cells (TBCs) and fewer killers among the TBCs. ONDs and normal controls were equally sensitive to PGE1. Though PGE-producing cells were depleted in the NWP population of normal and control ONDs, MS patients still had indomethacin-sensitive NK suppressors in the NWP population; these apparently did not suppress at the single cell effector level but at the level of recycling. MS and OND cerebrospinal fluid (CSF) cells' NK activity could not be 'enhanced' by indomethacin. Depression of interferon (IFN)-induced NK by PGE1 was greater in MS than in OND or normal controls perhaps through its effect on IFN-induced recycling. All subjects' cells maintained sensitivity to PGE1 after overnight incubation in the presence of PGE-producing cells (pre NW) or exogenous PGE1. In sharp contrast to normal and OND controls, MS NWP cells were still inhibited by PGE1 even after overnight incubation in the absence of PGE1.     

Combined lithium and valproate treatment and subsequent withdrawal: serotonergic mechanism of their interaction in discrete brain regions

Rats were administered with lithium carbonate (1 mmole/kg), valproate (300 mg/kg) and their combination for 12 days. Rats in the withdrawal group were treated for 10 days, followed by saline for 2 days. Mid-brain tryptophan levels increased in all the groups except lithium-treated rats. The administration of lithium together with valproate decreased tryptophan hydroxylase activity and 5-hydroxytryptamine levels in certain brain regions compared to either treatment alone. Also, the magnitude of valproate-induced 5-hydroxyindoleacetic acid elevation was decreased after combined treatment. Most of the changes observed after combined exposure persisted even after 2 days of treatment withdrawal. It appears from the data that combined administration of the two drugs produces persistent decrease in 5-hydroxytryptamine synthesis and turnover in the brain.     

Sulpiride-induced hyperprolactinemia and impotence in male psychiatric outpatients

The relationship between erectile dysfunction and sulpiride stimulatory effect on prolactin secretion was studied in 13 married male psychiatric outpatients. The patients population was comprised of 2 groups: patients with anxiety disorders resistant to minor tranquilizers who were treated with sulpiride up to 200 mg/day, and schizophrenic patients treated with sulpiride 600 mg/day. All the patients were maintained on maximal dose for a period of 3 weeks. Sexual function and blood prolactin levels were monitored once weekly. The patients who developed impotence were maintained on higher doses of sulpiride and exhibited higher prolactin levels in comparison to the potent patients. Restoration of potency was observed after reduction or discontinuation of sulpiride treatment. It is concluded that sulpiride induced impotence is associated with hyperprolactinemia.     

Power based association analysis (PBAT) of serotonergic and noradrenergic polymorphisms in bipolar patients with suicidal behaviour

BACKGROUND AND AIMS: Suicidality is a major health concern worldwide particularly in affective disorder patients. Attempted suicide is familial. There is strong neurobiological evidence showing that serotonergic and noradrenergic dysfunction is implicated in suicidal behaviours. We will apply now a new family based association strategy aimed to explain the genetic influence in suicidal behaviour by power based association test statistics (PBAT) in 336 bipolar patients assessed for suicidality within nuclear families. METHODS: By use of conditional power calculations, the approach screens all possible null hypotheses without biasing the nominal significance level, and it identifies the subset of phenotypes that has optimal power when tested for association by either univariate or multivariate family based association test (FBAT). Using this statistical approach (PBAT) we investigated polymorphisms in serotonergic and noradrenergic genes, considering suicidal behaviour severity instead of the dichotomous phenotype (presence of suicide attempt). RESULTS: COMT Val/Met polymorphism was not associated with suicide with high confidence (power=91%). On the other hand, the analysis of the other 12 markers in the adrenergic and serotonergic genes revealed that the TH allele tended towards association with higher severity of suicidal behaviour (p=0.060) but the power obtained was very low. CONCLUSIONS: The marginal finding of association between TH and severe suicidal behaviour are convergent with previous reports. On the other hand, our sample has enough power to exclude the other polymorphisms investigated as major candidate for suicidality in bipolar disorder.