Association of plasma free-3-methoxy-4-hydroxyphenyl (ethylene)glycol, natural killer cell activity and delirium in postoperative patients

The predictive value of a change in natural killer cell activity for delirium

PURPOSE

Few studies looking for an effective biomarker to predict delirium have been performed. This study was designed to investigate whether a change in inflammatory status, indicated by blood natural killer (NK) cell activity, predicts delirium.

METHODS

This prospective study, performed in 4 university and 1 general hospital from September, 2011 to October, 2012, included 29 patients. Eligible patients were 65-89years old, newly and emergently admitted. Patients were assessed daily, up to 7days, for occurrence of DSM-IV-defined delirium. The main outcome measure was change in blood NK cell activity between the first and second mornings after admission.

RESULTS

The mean change in blood NK cell activity on the second morning, compared to the first morning, in patients developing delirium (n=9) was significantly greater than that in patients without delirium (n=20) (6.0% [SD 8.4] vs. -1.4% [9.0], respectively, t=2.10, P=0.045). Significant difference between the groups was still found after adjusting for age, the history of previous delirium, and the Clinical Dementia Rating score (F=6.63, P=0.017). Of note is that 8 of 9 (89%) patients developing delirium had increased blood NK cell activity, as did only 8 of 20 (40%) patients without delirium, giving measurement of this parameter, for distinguishing the two groups, a sensitivity of 89%, specificity 60%, positive predictive value 50%, negative predictive value 92%, positive likelihood ratio 2.22, and negative likelihood ratio 0.19. When combining this predictor with another predictor, a Delirium Rating Scale-Revised-98 severity score of 5 or more at baseline, positive and negative likelihood ratios were 7.80 and 0.24, respectively.

CONCLUSION

Increase in blood NK cell activity may be associated with developing delirium. Further studies including larger numbers of patients are needed to justify the preventive use of drugs for patients meeting criteria for both predictors.

Biomarkers of delirium as a clue to diagnosis and pathogenesis of Wernicke-Korsakoff syndrome

BACKGROUND AND PURPOSE

Wernicke's encephalopathy (WE) and Korsakoff's syndrome are considered to be different stages of the same disorder due to thiamine deficiency, which is called Wernicke-Korsakoff syndrome (WKS). The earliest biochemical change is the decrease of α-ketoglutarate-dehydrogenase activity in astrocytes. According to autopsy-based series, mental status changes are present in 82% of WE cases. The objective of the present review is to identify possible underlying mechanisms relating the occurrence of delirium to WKS.

METHODS

Studies involving delirium in WKS, however, are rare. Therefore, first, a search was done for candidate biomarkers of delirium irrespective of the clinical setting. Secondly, the results were focused on identification of these biomarkers in reports on WKS.

RESULTS

In various settings, 10 biochemical and/or genetic biomarkers showed strong associations with the occurrence of delirium. For WKS three of these candidate biomarkers were identified, namely brain tissue cell counts of CD68 positive cells as a marker of microglial activation, high cerebrospinal fluid lactate levels, and MHPG, a metabolite of norepinephrine. Based on current literature, markers of microglial activation may present an interesting patho-etiological relationship between thiamine deficiency and delirium in WKS.

CONCLUSIONS

In WKS cases, changes in astroglia and microglial proliferation were reported. The possible loss-of-function mechanisms following thiamine deficiency in WKS are proposed to come from microglial activation, resulting in a delirium in the initial phase of WKS.

Plasma catecholamine metabolite levels and the activities of psychiatric symptoms in systemic lupus erythematosus

OBJECTIVES

Neuropsychiatric systemic lupus erythematosus (NPSLE) is accompanied by neurological or psychiatric symptoms that can be severe. We hypothesized plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) levels were the biological marker that reflected the severity of the NPSLE psychiatric symptoms, and we examined MHPG and HVA levels in systemic lupus erythematosus (SLE) patients.

METHODS

The participants were 42 healthy volunteers and 41 SLE patients. SLE patients were divided into the three groups: NPSLE with psychiatric symptoms (NP group), NPSLE without psychiatric symptoms (NN group), and SLE without neuropsychiatric symptoms (S group). All blood samples were drawn before (T0) and after 4 weeks of treatment (T4) in all SLE patients, and once in the healthy volunteers. Plasma levels of MHPG and HVA were analyzed using high-performance liquid chromatography.

RESULTS

Plasma MHPG levels at T0 were significantly increased in the SLE compared to those in healthy volunteers. The NN group had the greatest increase compared with other SLE patient groups. There were no significant differences in plasma HVA levels at T0 between the four groups, and there was also no difference in MHPG and HVA plasma levels between T0 and T4.

CONCLUSION

Hyperactivity of noradrenergic neurons and/or sympathetic nerves might be involved in SLE pathophysiology.

Evaluation and management of the elderly patient at risk for postoperative delirium

Geriatric patients are at a high risk for the development of postoperative delirium. By recognizing predisposing and precipitating risk factors, preventive measures can be undertaken to reduce this risk. Accurate and timely diagnosis is essential, and we offer therapeutic strategies to help reduce the high morbidity and mortality of this important condition.

Plasma levels of brain derived-neurotrophic factor and catecholamine metabolites are increased during active phase of psychotic symptoms in CNS lupus: a case report

In the present study, the authors reported a case of systemic lupus erythematosus (SLE) with central nervous system involvement (CNS lupus). The authors also longitudinally investigated plasma levels of brain-derived neurotrophic factor (BDNF) and catecholamine metabolites in the patient, and found that plasma levels of BDNF, 3-methoxy-4-hydroxyphenylglycol (MHPG), and homovanillic acid (HVA) were raised in accordance with the severity of psychotic symptoms in this case of CNS lupus. These results suggest that it is useful to measure plasma levels of BDNF and the catecholamine metabolites in order to predict the severity of psychotic symptoms in CNS lupus and to provide a differential diagnosis from that of steroid-induced psychosis.

Noradrenaline transporter and its turnover rate are decreased in blood lymphocytes of patients with major depression

Lymphocytes possess transporters of serotonin and dopamine, and also contain monoamines. The objective of this work was to determine the presence of noradrenaline transporters, the turnover rate of noradrenaline and serotonin in lymphocytes of major depression patients, and to correlate the biochemical parameters with the severity of the disorder. Lymphocytes from peripheral blood were isolated by Ficoll/Hypaque, and noradrenaline transporter was studied by binding of [3H]nisoxetine: control group (29, age 31.52+/-1.08, 7 men) and major depression patients (35, age 36.68+/-1.69, 6 men), Hospital Vargas de Caracas. Diagnostic was done by criteria of the American Psychiatric Association and severity by Hamilton Scale for Depression. Levels of noradrenaline, serotonin, 3-methoxy-4-hydroxyphenylglycol and 5-hydroxyindoleacetic acid were determined by HPLC. Turnover rate was evaluated by the ratios of monoamines and metabolites. Correlations were done between the biochemical parameters and the severity of depression. The score of Hamilton for Depression was 22.77+/-0.51. There was a reduction in the number of transporters in lymphocytes of patients, 0.95+/-0.27 versus 4.06+/-1.67 fmol/10(6) cells. Levels of monoamines and metabolites did not significantly differ between patients and controls. However, there was a higher monoamine/metabolite ratio in lymphocytes of patients, indicating a reduction of metabolic turnover rate. Also there was a relative greater concentration of noradrenaline than serotonin in the lymphocytes of the patients, as indicated by the ratio noradrenaline/serotonin. Noradrenergic and serotonergic turnover is decreased in blood peripheral lymphocytes of major depression patients; the reduction in noradrenaline transporter could be related to changes in intracellular levels, and these modifications could result in functional changes of the immune system.

Clinical response to antidepressant treatment and 3-methoxy-4-hydroxyphenylglycol levels: mini review

Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) may provide valuable information regarding central noradrenergic activity. In this article, we mainly reviewed about the associations between plasma MHPG levels and responses to antidepressant treatment. There exists heterogeneity of depression with regards to plasma levels of MHPG; in other words, depressed patients might be dichotomized into one group characterized by anxiety and/or perceptions of powerlessness with high plasma MHPG levels and another group characterized by psychomotor retardation with low plasma MHPG levels. In addition, it is possible that patients with lower pretreatment MHPG levels might respond to drugs that affect both noradrenergic neurons and serotonergic neurons or predominantly noradrenergic neurons. On the other hand, patients with higher pretreatment MHPG levels might respond to drugs that affect predominantly serotonergic neurons or GABAergic neurons. It is possible to predict the responses to antidepressant drugs by means of plasma MHPG levels in depressed patients.

Associations between baseline plasma MHPG (3-methoxy-4-hydroxyphenylglycol) levels and clinical responses with respect to milnacipran versus paroxetine treatment

The purpose of this study was to investigate the effects of milnacipran and paroxetine on plasma levels of catecholamine metabolites, and we attempted to elucidate the differences between the mechanisms of these drugs in catecholaminergic neurons. In depressed patients, we investigated the relationships among pretreatment levels of catecholamine metabolites, the changes in plasma catecholamine metabolite levels before and after administration of milnacipran or paroxetine, and clinical response to these drugs. Responders to milnacipran showed lower pretreatment levels of plasma 3-methoxy-4-hydroxyphenylglycol (pMHPG) than did nonresponders to milnacipran; there was also a positive correlation between changes in pMHPG levels and percent improvement of the score on the 17-item Hamilton Rating Scale for Depression (HRSD). On the other hand, responders to paroxetine showed higher pretreatment levels of pMHPG than did nonresponders to paroxetine, and a negative correlation was observed between changes in pMHPG levels and percent improvement of the HRSD score. However, a significant difference was not observed in the pretreatment plasma level of homovanillic acid between responders and nonresponders to treatment with milnacipran or paroxetine. These results suggest that there is an association between baseline pMHPG levels and clinical responses with respect to milnacipran versus paroxetine treatment.