catechol-O-methyltransferase Activity Research Articles

Coffee consumption during pregnancy increases the risk of preeclampsia in rats by inhibiting 2-methoxyestradiol production.

Preeclampsia (PE) is a pregnancy-specific disease that causes maternal symptoms such as high blood pressure and adverse pregnancy outcomes. 2-methoxyestradiol (2-MeO-E2), an endogenous metabolite of 17β-estradiol (E2) formed by Catechol-O-Methyltransferase (COMT), plays an important role in pregnancy. Our earlier studies have shown that polyphenols present in coffee can inhibit COMT activity, which may inhibit the formation of 2-MeO-E2 and contribute to PE. Therefore, the current study aims to investigate the possible effect and mechanism of coffee intake during pregnancy on PE in SD rats. Coffee is administered with or without cotreatment of 2-MeO-E2 to pregnant rats from the10th to the18th day of pregnancy. The results show that pregnant rats with coffee intake had prominent fetal growth restriction, hypertension and proteinuria, which can be ameliorated by co-treatment of 2-MeO-E2. In addition, coffee treatment leads to significantly decreased serum 2-MeO-E2. Therefore, the PE symptoms induced by coffee treatment is probably mediated by decreased 2-MeO-E2. Our findings provide new mechanistic insight into how coffee intake could lead to increased risk of PE, and demonstrate the effectiveness of 2-MeO-E2 supplementation as a potential therapeutic agent for PE.

Catechol-O-methyltransferase and monoamine oxidase B inhibitory activities of Australian bee pollen.

Bee pollen is an apicultural product collected by honeybees from flower stamens and used as a functional food worldwide. In the present study, we aim to elucidate the functions of Australian bee pollen. Australian bee pollen extracts and their main components were tested for catechol-O-methyltransferase (COMT) and monoamine oxidase B (MAOB) inhibitory activities. These enzymes are key neurotransmitters involved in Parkinson's disease and depression. Myricetin (5), tricetin (6), and luteolin (7) exhibited high COMT inhibitory activities (half maximal inhibitory concentration [IC50] = 23.3, 13.8, and 47.4 µM, respectively). In contrast, 5, 7, and annulatin (8) exhibited MAOB inhibitory activities (IC50 = 89.7, 32.8, and 153 µM, respectively). Quantitative analysis via high-performance liquid chromatography revealed that 5 was abundant in Australian bee pollen extracts. Our findings suggest that 5 contributes to the COMT and MAOB inhibitory activities of Australian bee pollen.

Udruženost polimorfizama gena za katehol-Ometiltransferazu sa terapijskim odgovorom i komplikacijama izazvanim levodopom kod Parkinsonove bolesti - rezime sadašnjih saznanja

Catechol-O-methyltransferase (COMT) is one of the cardinal enzymes in the degradation of catecholamines and levodopa. Genetic variants of the COMT gene may affect COMT enzyme activity. The most examined COMT gene polymorphism is the nonsynonymous single nucleotide polymorphism (SNP) in exon 4 (Val108/158Met; rs4680). This highly functional polymorphism is responsible for fourfold variations in enzyme activity and Dopamine catabolism. Recent data suggested that even synonymous SNPs of the COMT gene can lead to changes in enzyme activity. Genetically determined COMT activity can affect an individual's response to levodopa therapy and carries the risk of complications from prolonged levodopa use in Parkinson's disease (PD) patients. Identifying at-risk individuals through genetic susceptibility markers could help to prevent the development of levodopa-induced complications in PD.

Bioactive components and mechanisms of Pu-erh tea in improving levodopa metabolism in rats through COMT inhibition.

Catechol-O-methyltransferase (COMT) plays a central role in the metabolic inactivation of endogenous neurotransmitters and xenobiotic drugs and hormones having catecholic structures. Its inhibitors are used in clinical practice to treat Parkinson's disease. In this study, a fluorescence-based visualization inhibitor screening method was developed to assess the inhibition activity on COMT both in vitro and in living cells. Following the screening of 94 natural products, Pu-erh tea extract exhibited the most potent inhibitory effect on COMT with an IC50 value of 0.34 μg mL-1. In vivo experiments revealed that Pu-erh tea extract substantially hindered COMT-mediated levodopa metabolism in rats, resulting in a significant increase in levodopa levels and a notable decrease in 3-O-methyldopa in plasma. Subsequently, the chemical components of Pu-erh tea were analyzed using UHPLC-Q-Exactive Orbitrap HRMS, identifying 24 major components. Among them, epigallocatechin gallate, gallocatechin gallate, epicatechin gallate, and catechin gallate exhibited potent inhibition of COMT activity with IC50 values from 93.7 nM to 125.8 nM and were the main bioactive constituents in Pu-erh tea responsible for its COMT inhibition effect. Inhibition kinetics analyses and docking simulations revealed that these compounds competitively inhibit COMT-mediated O-methylation at the catechol site. Overall, this study not only explained how Pu-erh tea catechins inhibit COMT, suggesting Pu-erh tea as a potential dietary intervention for Parkinson's disease, but also introduced a new strategy for discovering COMT inhibitors more effectively.

A randomized trial of the effects of COMT inhibition on subjective response to alcohol: Moderation by baseline COMT activity and mediation of alcohol self-administration.

Poor inhibitory control and enhanced subjective response to alcohol are interrelated risk factors for alcohol use disorder (AUD) that share underlying neural substrates, including dopamine signaling in the right prefrontal cortex, a potential target for pharmacological intervention. Cortical dopamine inactivation is primarily regulated by catechol-O-methyltransferase (COMT), an enzyme with large variation in activity as a function of the COMT rs4680 (val158met) single nucleotide polymorphism. In a previous randomized, placebo-controlled trial of the COMT inhibitor tolcapone (200 mg TID) in non-treatment-seeking participants with AUD, we found that tolcapone, relative to placebo, reduced alcohol self-administration only among rs4680 val-allele homozygotes, whose COMT activity is higher than in met-allele carriers. We conducted secondary analyses of the effects of tolcapone and baseline COMT activity, as indexed by both rs4680 genotype and an enzymatic activity assay, on the subjective response to alcohol in a bar-laboratory paradigm among 60 participants in the previous trial. Tolcapone did not affect alcohol-induced stimulation or sedation more than placebo. However, baseline COMT activity moderated the effects of the drug on both outcomes, such that tolcapone-treated participants with higher baseline COMT activity had less stimulation (p = 0.008) and sedation (p = 0.053) than participants with lower baseline COMT activity and those treated with placebo. Additionally, alcohol-induced stimulation significantly mediated the interacting effects of baseline COMT activity and tolcapone on bar-laboratory self-administration. Tolcapone may reduce subjective response to alcohol more effectively among individuals with preexisting high COMT activity an effect that could account for the drug's reduction of alcohol consumption among these individuals.

Stalevo® : A pioneering treatment for OFF periods in Parkinsons disease.

Enzymatic metabolism is the key determinant of the overall bioavailability, brain penetration, and efficacy of levodopa in the treatment of Parkinsons disease (PD). Enzyme inhibitors in the form of peripheral dopa-decarboxylase inhibitors and monoamine oxidase type-B inhibitors have been successfully employed to maximize the utility of levodopa in both early- and late-stage PD. However, another major pathway of the peripheral metabolism of levodopa through catechol-O-methyltransferase (COMT) remains unchecked by those measures. Consequently, this becomes a major factor in determining the extent of delivery to the brain. The introduction of tolcapone as a potent and effective peripheral and central COMT inhibitor was frustrated by the emergence of hepatic toxicity. Only with the subsequent introduction of entacapone as an effective inhibitor of peripheral COMT activity has it become possible to fully control the peripheral metabolism of levodopa and to optimize its delivery to the brain. At a single-dose level of 200 mg, the efficacy of entacapone in reducing OFF time and increasing ON time has led to its widespread use for the treatment of "wearing off". To maximize the efficacy of entacapone and to time-lock its pharmacokinetic profile to that of levodopa, a triple combination of levodopa, carbidopa, and entacapone in the form of Stalevo® that allowed for flexibility in levodopa dosing was introduced early in the 21st century. This pioneering development has been successfully used worldwide for the past 20 years. This review considers the role of all three classes of enzyme inhibitors in PD medicine.

Structural and Computational Analyses of the Unique Interactions of Opicapone in the Binding Pocket of Catechol O-Methyltransferase: A Crystallographic Study and Fragment Molecular Orbital Analyses.

A third-generation inhibitor of catechol O-methyltransferase (COMT), opicapone (1), has the 3-nitrocatechol scaffold as do the second-generation inhibitors such as entacapone (2) and tolcapone (3), but only 1 can sustainably inhibit COMT activity making it suitable for a once-daily regimen. These improvements should be attributed to the optimized sidechain moiety (oxidopyridyloxadiazolyl group) of 1 substituted at the 5-position of the 3-nitrocatechol ring. We analyzed the role of the sidechain moiety by solving the crystal structures of COMT/S-adenosylmethionine (SAM)/Mg/1 and COMT/S-adenosylhomocysteine (SAH)/Mg/1 complexes. Fragment molecular orbital (FMO) calculations elucidated that the dispersion interaction between the sidechains of Leu 198 and Met 201 on the β6β7-loop and the oxidopyridine ring of 1 were unique and important in both complexes. In contrast, the catechol binding site made a remarkable difference in the sidechain conformation of Lys 144. The ε-amino group of Lys 144 was outside of the catalytic pocket and was replaced by a water molecule in the COMT/SAH/Mg/1 complex. No nitrocatechol inhibitor has ever been reported to make a complex with COMT and SAH. Thus, the conformational change of Lys 144 found in the COMT/SAH/Mg/1 complex is the first crystallographic evidence that supports the role of Lys 144 as a catalytic base to take out a proton ion from the reaction site to the outside of the enzyme. The fact that 1 generated a complex with SAH and COMT also suggests that 1 could inhibit COMT twofold, as a typical substrate mimic competitive inhibitor and as a product-inhibition enhancer.

Consistent Effects of Once-Daily Opicapone 50 mg on COMT Activity Across Participants: A Pooled Post Hoc Analysis of Two Phase 1 Studies (P14-11.014)

<h3>Objective:</h3> To assess effects of adjunctive opicapone (OPC) 50 mg on catechol-O-methyltransferase (COMT) activity by participants’ baseline characteristics. <h3>Background:</h3> OPC is a once-daily COMT inhibitor approved as adjunctive treatment to carbidopa/levodopa (CD/LD) in patients with Parkinson’s disease (PD) experiencing “OFF”-episodes. In two Phase 3 trials, OPC reduced daily “OFF”-time in patients with PD and motor fluctuations. Phase 1 trials also showed that adding OPC 50 mg to CD/LD in healthy individuals and patients with PD decreased variability in plasma levodopa (LD) levels and COMT activity. However, the effects of participants’ baseline characteristics on COMT inhibition remain unknown. <h3>Design/Methods:</h3> This post hoc analysis included data from 2 open-label Phase 1 studies (Study 1: 16 patients with PD receiving immediate-release CD/LD; Study 2: 18 healthy participants receiving extended-release CD/LD) assessing the effect of OPC 50 mg on LD pharmacokinetics (PK). Blood samples to assess LD PK and soluble-COMT (S-COMT) activity were collected before and after 14–15 days of once-daily OPC 50 mg. Pooled data on S-COMT inhibition were analyzed by participants’ baseline characteristics: disease state (PD vs healthy), sex (male vs female), ethnicity (Hispanic/Latino vs non-Hispanic/Latino), body mass index (&lt;25 vs ≥25), and baseline S-COMT activity. <h3>Results:</h3> OPC added to CD/LD decreased mean (95% CI) S-COMT activity by ≥80% in patients with PD and healthy participants (Study 1: 83.0% [80.5–85.4%]; Study 2: 80.1% [78.5–81.8%]; Pooled: 81.4% [80.0–82.9%]). Mean percent reduction in S-COMT activity was 79–85% for all subgroups in individual and pooled studies, although some subgroups had small numbers of participants. Variability in S-COMT activity was lower in all participants after OPC compared to baseline. <h3>Conclusions:</h3> Adding once-daily OPC 50 mg to CD/LD resulted in substantial S-COMT inhibition with reduced variability regardless of baseline characteristics. In all participants, COMT inhibition shown by OPC with CD/LD leads to more consistent daily LD exposure. <b>Disclosure:</b> Gordon Loewen has received personal compensation for serving as an employee of Neurocrine. Gordon Loewen has received stock or an ownership interest from Neurocrine. Gordon Loewen has received intellectual property interests from a discovery or technology relating to health care. Kurt Olson has received personal compensation for serving as an employee of Neurocrine Biosciences Inc. Kurt Olson has stock in Neurocrine Biosciences Inc. Dr. Liang has received personal compensation for serving as an employee of Neurocrine Biosciences. Dr. Liang has stock in Neurocrine Biosciences. Dr. Klepitskaya has received personal compensation for serving as an employee of Neurocrine Biosciences, Inc.

Rare Catechol-O-methyltransferase Missense Variants Are Structurally Unstable Proteasome Targets.

Catechol-O-methyltransferase (COMT) is a key enzyme in the metabolism of catecholamines. Substrates of the enzyme include neurotransmitters such as dopamine and epinephrine, and therefore, COMT plays a central role in neurobiology. Since COMT also metabolizes catecholamine drugs such as L-DOPA, variation in COMT activity could affect pharmacokinetics and drug availability. Certain COMT missense variants have been shown to display decreased enzymatic activity. Additionally, studies have shown that such missense variants may lead to loss of function induced by impaired structural stability, which results in activation of the protein quality control system and degradation by the ubiquitin-proteasome system. Here, we demonstrate that two rare missense variants of COMT are ubiquitylated and targeted for proteasomal degradation as a result of structural destabilization and misfolding. This results in strongly reduced intracellular steady-state levels of the enzyme, which for the L135P variant is rescued upon binding to the COMT inhibitors entacapone and tolcapone. Our results reveal that the degradation is independent of the COMT isoform as both soluble (S-COMT) and ER membrane-bound (MB-COMT) variants are degraded. In silico structural stability predictions identify regions within the protein that are critical for stability overlapping with evolutionarily conserved residues, pointing toward other variants that are likely destabilized and degraded.

Effects of childhood trauma on aggressive behaviors and hippocampal function: the modulation of COMT haplotypes.

Aggression is a commonly hostile behavior linked to the hippocampal activity. Childhood trauma (CT) exposure has been associated with altered sensitization of the hypothalamic-pituitary-adrenal (HPA) axis and hippocampal volume，which could increase violent aggressive behaviors. Additionally, Catechol-O-methyltransferase (COMT), the major dopamine metabolism enzyme, is implicated in stress responsivity, including aggression. Hence, CT exposure may affect aggression through the effect on the hippocampal function, which might also be modulated by the COMT variations. This study examined whether both CT and haplotypes of COMT moderate hippocampal function and thus affect human aggressive behavior. We obtained bilateral hippocampal functional connectivity maps using resting state functional magnetic resonance imaging (MRI) data. COMT haplotype estimation was performed using Haploview 4.2 and PHASE 2.1. Then we constructed a moderated mediation model to study the effect of the CTQ × COMT on aggressive behavior. Three major haplotypes were generated from thirteen single nucleotide polymorphisms (SNPs) within the COMT gene and formed three haplotypes corresponding to high, medium, and low enzymatic activity of COMT. The results showed interactive relationships between the Childhood Trauma Questionnaire (CTQ) and COMT with respect to the functional connectivity (FC) of the bilateral hippocampus (HIP)-orbital frontal cortex (OFC). Specifically, CT experience predicted lower negative HIP-OFC coupling in the APS and HPS haplotypes corresponding to the medium and high enzymatic activity of COMT, but greater FC in the LPS haplotypes corresponding to the low enzymatic activity. We also observed a conditional mediation effect of the right HIP-OFC coupling in the link between COMT and aggressive behavior that was moderated by CT experience. These results suggest that CT and COMT have a combined effect on aggressive behavior through hippocampal function. This mediation analysis sheds light on the influence of childhood experience on aggressive behavior in different genetic backgrounds.

COMT rs4680 and DRD2 rs6275 variants and their association with YMRS scores in children with early-onset bipolar disorder

Background and objectivesBipolar disorder (BD) is a clinical status with at least one manic, hypomanic or mixed attacks. Genetic factors take part significantly in early-onset BD (EOBD). Dopamine receptors (DRD) act in neurological mechanisms like motivation, learning, memory, and, control of neuroendocrine signaling. DRD2 receptor has been reported to influence the stability of DRD2 transcript. Catechol-O-Methyl transferase (COMT) inactivates catecholamines and Val158Met variation on COMT has effects on COMT activity. This study aims to explore DRD2 and COMT variants in the clinical development of EOBD. MethodsIn this case-control study, 102 EOBD patients and 168 healthy control subjects were used. DRD2 rs6275 and COMT Val158Met variations were detected by real-time polymerase chain reaction (RT-PCR). Young Mania Rating Scale (YMRS) was utilized to determine the EOBD severity. ResultsFor DRD2 rs6275 and COMT Val158Met polymorphisms, no significant relationship was observed in the genotype and allele frequencies between patient and control groups. Nevertheless, TT genotype carriers of DRD2 rs6275 polymorphism demonstrated significantly increased YMRS scores when compared with CC and CT genotype carriers (p = 0.039). Nevertheless, no significant difference was observed between COMT Val158Met genotypes and YMRS scores. ConclusionsWe suggest that the DRD2 rs6275 TT variant can be associated with symptom severity in children with EOBD and can have a clinical significance in EOBD pathogenesis. However, these results need to be confirmed with larger samples of patient and control groups.

Висока частота гомозиготного генотипу 472АА COMT (Val158) гена катехол-О-метилтрансферази (COMT) у дітей із синдромом подразненого кишечника

Following the biopsychosocial model of medicine, the pathophysiological basis of irritable bowel syndrome (IBS) is a combination of biological, psychoemotional, and psychosocial factors, the contribution of each of them to the development of this disorder remains unclear. Psychoemotinal factors, which are involved in the pathogenesis of IBS, are caused not only by the environment but also by the metabolism of catecholamines, particularly by the functional activity of catechol-O-methyltransferase (COMT). Purpose - to determine the role of Val158Met COMT polymorphism in development of IBS in children; to identify associations between genotype and clinical variant of the disorder and the nature of the provoking factor. Materials and methods. The material for the molecular genetic study were DNA samples obtained from nuclear cells of venous blood of 54 patients aged 6-12 years with diagnosed IBS. In 48 practically healthy children of the same age DNA samples were isolated from buccal epithelial cells. Molecular genetic study of single nucleotide polymorphism rs4680 of COMT gene was performed by polymerase chain reaction followed by analysis of restriction fragment length polymorphism. Microsoft Excel 2016 and GraphPad Prism 5 software were used for statistical analysis. Results. We have revealed significant differences in the distribution of Val158Met COMT genotypes in children with IBS in comparison with the control group. There was established that the 472GА COMT is more prevalent in healthy children and has a protective role in the development of IBS. In contrast, homozygous genotypes 472GG and 472AA, which are associated with changes in functional activity of enzyme COMT, may be considered as the risk factors for IBS (p≤0.0001). Conclusions. Genotype 472АА COMT was mostly detected in сhildren with stress-associated IBS, which is more related to dysnociception, disorders of cognition, and emotional disturbances. The higher prevalence of 472GA COMT heterozygotes among children with postinfectious IBS and IBS associated with antibiotic therapy indicates a less important role for the psychoemotional component and nociceptive disorders in the onset of this disorder (p=0.03). The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Catechol-O-Methyltransferase (COMT) Enzyme Level In Preoperative Anxiety Patients

Background: Incidence of perioperative anxiety is very high, many preoperative patient experience anxiety . Thiamine acts as an essential nutrition funtionate as cofactor enzyme in most of mitochondria in brain. Brain is very susceptible to thiamine deficiency because its dependency on mitochondrial ATP production. Decreased ATP production result in inhibition of COMT activity. Low COMT levels indicated tendency for anxiety. The aim of this study is to determine the effect of thiamine in increasing COMT enzyme levels in patient with preoperative anxiety&#x0D; Methods : A true experiment with pretest-posttest control group and double-blind design conducted at the Department of Anesthesia and Intensive Care of University of North Sumatra in August 2019. The 60 patients were analyzed which were planned for and done an elective surgery under general anesthesia. Preoperative anxiety was measured with Amsterdam Preoperative Anxiety and Information Scale (APAIS) and COMT enzyme level measured by ELISA assays. &#x0D; Results : The results showed that from 64 patients had incidence of preoperative anxiety in this study was 48.3%. We found that there is significant differences in COMT enzyme levels in thiamine group compared to control (p value = 0.001). In addition, it was seen that in thiamine group had an increased COMT levels from 0.96 ng/dL to 1.78 ng/dL, while in control group there also slight increasing from 0.44 ng/dL to 0.78 ng/dL. This show that increase in COMT levels is greater in thiamine group than control group. &#x0D; Conclusion : Thiamine can cause increasing COMT enzyme levels in patients scheduled for elective surgery with preoperative anxiety under general anesthesia

Effects of pharmacological and genetic regulation of COMT activity in alcohol use disorder: a randomized, placebo-controlled trial of tolcapone.

Alcohol Use Disorder (AUD) is characterized by loss of control over drinking. Behavioral control is mediated, in part, by cortical dopamine signaling. Inhibition of catechol-O-methyltransferase (COMT), the enzyme primarily responsible for cortical dopamine inactivation, may increase cortical dopamine, especially among individuals with genetically mediated lower dopaminergic tone, such as COMT rs4680 (val158met) val-allele homozygotes. This study was a randomized, placebo-controlled, pharmacogenetic trial of the COMT inhibitor tolcapone. Ninety non-treatment-seeking AUD individuals were prospectively genotyped for rs4680 and randomized to tolcapone (200 mg t.i.d.) or placebo for 8 days. At baseline and on day 7, peripheral COMT activity was assayed, and participants completed an fMRI alcohol cue-reactivity task; on day 8, they completed a bar-lab paradigm. Primary outcomes were: (1) natural drinking during the medication period; (2) alcohol self-administration in the bar lab; and (3) alcohol cue-elicited cortical (right inferior frontal gyrus [rIFG]) and ventral striatal activation. At baseline, the rs4680 val-allele had an additive effect on COMT activity. Tolcapone, relative to placebo, reduced COMT activity in all genotype groups. COMT genotype moderated tolcapone’s effect on drinking during the medication period and in the bar lab, such that tolcapone, relative to placebo, reduced drinking only among val-allele homozygotes. Tolcapone did not affect cue-elicited ventral striatal activation but reduced rIFG activation; less rIFG activation on day 7 was associated with less drinking during the medication period. Taken together, these data suggest that COMT inhibition may reduce drinking specifically among individuals genetically predisposed to excessive COMT activity and potentially low cortical dopamine tone.ClinicalTrials.gov identifier: NCT02949934 https://clinicaltrials.gov/ct2/show/NCT02949934

The Role of Mycotoxin in Myecetoma Pathogenesis

Myecetoma is one of the neglected tropical diseases, most prevalent in tropical and subtropical regions in the area known as myecetoma belt. It is caused either by fungi (eumycetes) or bacteria (actinomycetes). We suggest that, through their strong and stable, mycotoxin inhibits pain and aryl hydrocarbon receptor actions and promotes IL-17 release. Furthermore, it affects Catechol-O-methyltransferase (COMT), which is responsible for male sexual orientation and this explains the predominance of myecetoma among men and we suggest that the size of lesion is related to the strength of COMT activity in male patients. Due to the absence of laboratory facilities, we are not able to achieve more than these suggestions, so experimental studies are recommended.

Integrated Mass Spectrometry Reveals Celastrol As a Novel Catechol-O-methyltransferase Inhibitor.

Natural product celastrol is known to have various biological activities, yet its molecular targets that correspond to many activities remain unclear. Here, we used multiple mass-spectrometry-based approaches to identify catechol-O-methyltransferase (COMT) as a major binding target of celastrol and characterized their interaction comprehensively. Celastrol was found to inhibit the enzymatic activity of COMT and increased the dopamine level in neuroendocrine chromaffin cells significantly. Our study not only revealed a novel binding target of celastrol but also provided a new scaffold and cysteine hot spot for developing new generation COMT inhibitors in combating neurological disorders.

Association between S-COMT activity and impulsive and premeditated aggression in a population of violent offenders: preliminary results of a cross sectional study

Aggression can be conceptualised as a physical act towards another person, verbal offenses, destructive acts towards objects, and self-inflicted harmful acts. It is highly frequent in the context of Antisocial Personality Disorder (ASPD) and has been correlated to disturbances in the dopaminergic system. In the prefrontal cortex, the dopamine metabolism depends on catechol-O-methyltransferase (COMT). DRD2 receptors also play a role in the expression of aggression by modulating dopamine metabolism, in the striatum. In this study, we evaluated the association between COMT activity and type of aggression, in a sample of violent male offenders. Participants were subjected to sociodemographic, clinical, and psychometric evaluation through standardised instruments. Erythrocyte S-COMT activity was measured, and COMT and the DRD2 genotypes were analysed. Individuals displaying impulsive aggression showed lower S-COMT erythrocyte activity (p=0.026) and lower frequency of Val/Val (rs4680) genotype than individuals with premeditated aggression (p=0.047). S-COMT erythrocyte activity was positively correlated with the PCL-R total score (r=0.34; p=0.018). In conclusion, our preliminary results indicate that COMT can be associated to different aggression types in violent offenders, and it can represent a possible pharmacological target for the treatment of impulsive and premeditated aggression, in incarcerated patients.

Extra virgin olive oil-based phospholipid complex/self-microemulsion enhances oral absorption of salvianolic acid B through inhibition of catechol-O-methyltransferase-mediated metabolism

The oral bioavailability of many phenolic acid drugs is severely limited due to the high hydrophilicity and extensive first-pass effect induced by catechol-O-methyltransferase (COMT) metabolism. The present study investigated the inhibitory activity of the pharmaceutical excipients of extra virgin olive oil (EVOO) against COMT and evaluated the potential of a self-microemulsion loaded with a phospholipid complex containing EVOO for oral absorption enhancement of salvianolic acid B (SAB), a model phenolic acid. In vitro COMT assay showed that EVOO could effectively inhibit enzyme activity in the rat liver cytosol. Next, the SAB phospholipid complex/self-microemulsion containing EVOO (named SP-SME1) was prepared and characterized (particle size, 243.60 ± 6.96 nm and zeta potential, –23.67 ± −1.36 mV). The phospholipid complex/self-microemulsion containing ethyl oleate (EO) (named SP-SME2) was taken as the control group. Compared with free SAB, the apparent permeability coefficient (Papp value) of the two SP-SMEs significantly increased (12.0-fold and 10.90-fold). Pharmacokinetic study demonstrated that the AUC0-∞ value of SAB for the SP-SME1 group significantly increased by 4.72 and 2.82 times compared to those for free SAB (p < 0.001) and SP-SME2 (p < 0.01), respectively. Moreover, the AUC0-∞ value of monomethyl-SAB (metabolite of SAB, MMS) for the SP-SME1 group decreased by 0.83 times compared to that for SP-SME2. In conclusion, the EVOO-based phospholipid complex/self-microemulsion greatly enhanced the oral absorption of SAB, which was mainly attributed to the inhibition of COMT activity induced by EVOO.

The Associations between COMT and MAO-B Genetic Variants with Negative Symptoms in Patients with Schizophrenia.

Negative symptoms of schizophrenia, including anhedonia, represent a heavy burden on patients and their relatives. These symptoms are associated with cortical hypodopamynergia and impaired striatal dopamine release in response to reward stimuli. Catechol-O-methyltransferase (COMT) and monoamine oxidase type B (MAO-B) degrade dopamine and affect its neurotransmission. The study determined the association between COMT rs4680 and rs4818, MAO-B rs1799836 and rs6651806 polymorphisms, the severity of negative symptoms, and physical and social anhedonia in schizophrenia. Sex-dependent associations were detected in a research sample of 302 patients with schizophrenia. In female patients with schizophrenia, the presence of the G allele or GG genotype of COMT rs4680 and rs4818, as well as GG haplotype rs4818-rs4680, which were all related to higher COMT activity, was associated with an increase in several dimensions of negative symptoms and anhedonia. In male patients with schizophrenia, carriers of the MAO-B rs1799836 A allele, presumably associated with higher MAO-B activity, had a higher severity of alogia, while carriers of the A allele of the MAO-B rs6651806 had a higher severity of negative symptoms. These findings suggest that higher dopamine degradation, associated with COMT and MAO-B genetic variants, is associated with a sex-specific increase in the severity of negative symptoms in schizophrenia patients.

Interaction of silver nanoparticles with catechol O-methyltransferase: Spectroscopic and simulation analyses

Catechol O-methyltransferase, an enzyme involved in the metabolism of catechol containing compounds, catalyzes the transfer of a methyl group between S-adenosylmethionine and the hydroxyl groups of the catechol. Furthermore it is considered a potential drug target for Parkinson’s disease as it metabolizes the drug levodopa. Consequently inhibitors of the enzyme would increase levels of levodopa. In this study, absorption, fluorescence and infrared spectroscopy as well as computational simulation studies investigated human soluble catechol O-methyltransferase interaction with silver nanoparticles. The nanoparticles form a corona with the enzyme and quenches the fluorescence of Trp143. This amino acid maintains the correct structural orientation for the catechol ring during catalysis through a static mechanism supported by a non-fluorescent fluorophore–nanoparticle complex. The enzyme has one binding site for AgNPs in a thermodynamically spontaneous binding driven by electrostatic interactions as confirmed by negative ΔG and ΔH and positive ΔS values. Fourier transform infrared spectroscopy within the amide I region of the enzyme indicated that the interaction causes relaxation of its β−structures, while simulation studies indicated the involvement of six polar amino acids. These findings suggest AgNPs influence the catalytic activity of catechol O-methyltransferase, and therefore have potential in controlling the activity of the enzyme.