Serum pseudocholinesterase in psychiatric patients

Genetic Association of Butyrylcholinesterase with Major Depressive Disorder

Major depressive disorder (MDD) is characterized as clinical depression, which primarily affects the mood and behaviour of an individual. In the present study butyrylcholinesterase (BChE), a co-regulatory cholinergic neurotransmitter enzyme implicated in several putative neuronal and non-neuronal physiological roles was investigated for its role in MDD. Eighty MDD patients and sixty-one healthy controls were recruited for the study. BChE activity was measured by Ellman's method using serum while DNA samples of the patients were genotyped for BCHE polymorphisms rs3495 (c.*189G > A) and rs1803274 (c.1699G > A) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and tetra-primer Amplification Refractory Mutation System- polymerase chain reaction (ARMS-PCR). The genotyping was further validated by Sanger Sequencing. Biochemical estimation of serum BChE levels revealed a statistically significant decrease of enzyme activity in MDD patients (69.96) as compared to healthy controls (90.97), which was independent of age and gender. BCHE single nucleotide polymorphism rs1803274 genotype GA was found to be associated with the disease under a dominant model (OR 2.32; 95% CI 1.09-4.96; p value = 0.025). Furthermore, risk allele-A frequency was higher in cases (p value = 0.013) than control. Carriers of rs1803274 GA genotype showed reduced mean BChE activity than wild-type allele GG homozygotes (p value = 0.040). Gender-based analysis revealed a protective role of rs3495 in females (χ² = 6.87, p value = 0.032, RM: OR 0.173, CI = 0.043-0.699 (p value = 0.017). In addition, rs1803274 risk allele-A was observed to be significantly higher in males (χ² = 4.258, p value = 0.039). In conclusion, the present study is indicative of a role of BChE in the pathophysiology of MDD where genetic polymorphisms were observed to effect BChE activity. Further replication studies in different ethnicities are recommended to validate the current observations.

Biochemical Analysis and Association of Butyrylcholinesterase SNPs rs3495 and rs1803274 with Substance Abuse Disorder

Addiction is a complex mental and behavioral disorder that changes the neurochemistry and physiology of the brain. Genetics also plays a significant role in the pathophysiology of addiction. Butyrylcholinesterase (BChE), a cholinergic enzyme, has been implicated in the metabolism of various drugs, including cocaine, and an association between single-nucleotide polymorphisms (SNPs) of the butyrylcholinesterase gene (BCHE) and neuronal disorders has been reported. We report here the first investigation to be conducted on the status of BChE activity and the potential association of two BCHE gene SNPs, rs3495 (c.*189G > A) and rs1803274 (c.1699G>A, p.Ala567Thr, K-variant), with addiction vulnerability in heroin, hashish and polydrug users. Seventy-five individuals with an addiction to heroin, hashish and/or polydrug use were recruited to this study. BChE levels in the plasma were determined by Ellman's principle. SNPs were genotyped by standard procedures, followed by Sanger sequencing. Plasma BChE levels were found to be significantly higher (p ≤ 0.05) in addicts (mean ± standard error of the mean 0.031 ± 0.004 μmol/L/min; 95% confidence interval [CI] 0.024-0.038) than in non-addicts (controls) (0.014 ± 0.001 μmol/L/min; 95% CI 0.012-0.017). Statistical significant differences were also observed between the addicted cohorts. A statistically significant association for both SNPs (rs3495 and rs1803274) was not observed in addicted subjects tested in the dominant, recessive and allele genetic models, but trends of variations of the rs3495 risk G allele were noted. The authors conclude that BChE plays significant roles in addiction pathophysiology as increased BChE activity in blood samples obtained from the cohorts with addiction was evident. Further studies in this direction may provide novel approaches for the treatment of addiction, but studies with a larger sample size and different ethnic groups are warranted for broader conclusions to be drawn.

Pseudocholinesterase levels in patients under electroconvulsive therapy

Objectives:

In this study, we aimed to retrospectively assess the correlation of pseudocholinesterase (PChE) levels with age, gender, body weight and diagnosed psychiatric diseases in electroconvulsive therapy (ECT) cases.

Methods:

This retrospective study was conducted at Bülent Ecevit University Hospital, Zonguldak, Turkey, between 2007 and 2011. In the study, 193 ECT case files were retrospectively scanned to evaluate PChE values before ECT and other file information.

Results:

There was no difference between gender in terms of PChE levels. Correlation analysis determined a weakly positive correlation between age (p=0.013; correlation coefficient [cc]: 0.178) and body weight (p<0.001; cc: 0.273) and PChE levels. No correlation was found between age, gender, weight or psychiatric diagnosis, and PChE levels.

Conclusion:

Neuromuscular blockage is a significant factor that increases patient safety, while increasing the efficacy of ECT. In choosing muscle relaxant agents, both patient factors and the pharmacological properties of the neuromuscular blocker should be considered. We think that in situations with delayed recovery of ECT cases without identified PChE levels, low PChE levels must be considered.

Serum cholinesterase in obsessive-compulsive disorder

Levels of serum cholinesterase (PsChe) were measured in 32 drug-free patients with obsessive-compulsive disorder (OCD) and 32 sex- and age-matched healthy normal volunteers. No significant differences between OCD patients and normal subjects were found in PsChe levels. A significant positive correlation between patients' PsChe levels and the severity of anxiety, as measured by the Hamilton Rating Scale for Anxiety, was found, in agreement with the hypothesis of a relationship between state anxiety and PsChe activity. In contrast to findings in other reports, PsChe levels significantly increased after 10 weeks of antiobsessional pharmacological treatment, underscoring the potential influence of drugs on PsChe activity.

Plasma cholinesterase isozymes and REM latency in schizophrenia

The relation between electroencephalographic sleep parameters and plasma cholinesterase isozymes was examined in a group of 19 unmedicated schizophrenic patients. Rapid eye movement (REM) latency was found to be significantly inversely correlated with isozyme 3 (mainly acetylcholinesterase). The results are discussed in relation to cholinergic involvement in the regulation of REM sleep and in the pathophysiology of schizophrenia.

Biochemical measures in patients with a somatoform pain disorder, before, during, and after treatment with amitriptyline with or without flupentixol

The possible relationship between a number of biochemical parameters and measures of pain and depression was studied in chronic pain patients without a major depression. In a double-blind crossover study, patients were treated with amitriptyline combined with a low dose of flupentixol or placebo. We investigated whether pretreatment biochemical values correlated with initial data on pain and/or depression, or whether they had predictive value for treatment outcome. We also studied systematically the effect of both treatment regimes on the biochemical parameters themselves and their relation to the plasma levels of amitriptyline. From our results, the possible involvement of the serotonin system in somatoform pain disorder is confirmed and no direct relation with the noradrenergic system could be inferred. The lack of involvement of a number of putative, depression-related, biochemical parameters suggests that affective disorders and pain syndromes do not share all mechanisms in common.

A novel hypothesis for the psycho-modulating effects of lithium: the role of essential fatty acids, eicosanoids and sub-cellular second messengers

Evidence is presented for a novel proposal for the mechanism of action of lithium in manic depressive psychosis. Lithium has well established effects on catecholaminergic--and hormone--stimulated adenyl cyclase activity and on cyclic AMP formation. Although there is conflicting evidence in the literature concerning the effects of the ion on cyclic nucleotide phosphodiesterase, not much is known of the effects of lithium on cyclic GMP. These two second messengers have been proposed to be mutually antagonistic in their actions but that a physiological balance between the two is essential for maintaining homeostasis of the human psyche. An in vivo animal study was undertaken to determine the effects of chronic lithium treatment on the dynamics and kinetics of these two cyclic nucleotides and phosphodiesterase in rat cerebral cortex. From these results, a possible functional coupling mechanism between the two second messenger systems and the effects of lithium are proposed. Lithium by means of its specific site of action, is unique among psychoactive drugs in that it can control both phases of bipolar illness. This point of action is proposed to be the metabolism of free fatty acids where lithium, by altering the availability of precursors for eicosanoid metabolism, is able to modulate both noradrenergic- and cholinergic-dependent pathways. By doing this, the ion is able to reestablish lost control over adrenergic and cholinergic balance critical for thought process and mood stability.

Quantitative analyses of plasma cholinesterase isozymes in haloperidol-treated rats

We describe a quantitative slab gel electrophoresis procedure that allows quantitative determination of plasma levels of discrete cholinesterase isozymes. Using this method, the effects of haloperidol treatment on plasma cholinesterase isozyme levels were examined in normal rats. Eight isozymes were detected by enzymatic reaction with either of two substrates (alpha-naphthyl acetate, NA; acetylthiocholine iodide, AcTCh), and then quantified using densitometric scanning. With AcTCh substrate, the activities of two major isozymes (1 and 2) were found to be linear with increasing quantities of applied plasma. With NA as substrate, Iso-OMPA (a pseudocholinesterase inhibitor) inhibited activities of all isozymes, except isozymes 2 and 8. With either substrate, BW284C51 (acetylcholinesterase inhibitor) inhibited 100% and 13% of activity of isozymes 2 and 8, respectively, and with AcTCh substrate, 37% of isozyme 1. Based on the differential patterns of substrate specificity and action of inhibitors, and the reproducibility of patterns, we propose that these isozymes represent distinct molecular species. Short-term (14 days) and long-term (45 days) haloperidol treatment both resulted in altered levels of specific cholinesterase (ChE) isozymes. On the average, with AcTCh substrate, haloperidol treatment increased levels of isozymes 1 and 2 by 30% and 8%, respectively, after 14 days, and by 50% and 30%, respectively, after 45 days. Isozymes 3 through 8 showed minor changes. Plasma levels of isozymes 1 and 2 returned to baseline pretreatment values after a 40-day drug-free period. No significant change was observed after either short- or long-term treatment with clozapine, imipramine, or saline, or after an acute (less than 5 days) haloperidol treatment. No change was noted in RBC-ChE levels as function of treatment. These findings indicate that, in the rat, chronic haloperidol treatment results in differential changes in the plasma levels of discrete ChE isozymes. We have suggested that these changes reflect an alteration of central dopaminergic-cholinergic balance.

Lithium modulation of cortical cyclic nucleotides: evidence for the Yin-Yang hypothesis

Rats were subjected to chronic treatment with lithium chloride (0.2-0.3%) over a period of 3 weeks. The activity of cortical phosphodiesterase (EC 3.1.4.17) was determined simultaneously with cyclic AMP and cyclic GMP content and compared to control, untreated animals. Lithium, at therapeutic serum concentrations was found to suppress cyclic AMP levels with a concomitant increase in cyclic AMP-phosphodiesterase activity. A simultaneous two-fold increase in cyclic GMP was observed. Through the alteration of cortical cholinergic activity with physostigmine and the use of cyclic GMP as a cholinergic marker, we were able to demonstrate a novel cholinotropic property of lithium to stimulate synthesis of cyclic GMP. This effect appears to be linked, in a Yin-Yang mechanism, to the observed suppression of cyclic AMP induced by lithium through activation of cyclic AMP-phosphodiesterase.

Pseudocholinesterase in obsessive-compulsive patients

Levels of pseudocholinesterase (PsChe) were measured in 20 patients with obsessive-compulsive disorder (OCD) and 20 healthy volunteers. The OCD group had significantly higher PsChe serum activity than in their sex- and age-matched control group. Patients' scores on the Hamilton Rating Scale for Anxiety (HRS-A) and the Beck Depression Inventory (BDI) were not correlated with their PsChe levels. The results provide additional support for the observation of higher PsChe levels among anxiety-related psychiatric conditions. However, the relationships among anxiety, depression, and PsChe appear to be complex. The nature and implications of elevated PsChe levels are still unknown.