Chronic Behavioral and Neurochemical Effects of Four Novel N-Benzyl-2-phenylethylamine Derivatives Recently Identified as "Psychoactive" in Adult Zebrafish Screens

Potently affecting human and animal brain and behavior, hallucinogenic drugs have recently emerged as potentially promising agents in psychopharmacotherapy. Complementing laboratory rodents, the zebrafish (Danio rerio) is a powerful model organism for screening neuroactive drugs, including hallucinogens. Here, we tested four novel N-benzyl-2-phenylethylamine (NBPEA) derivatives with 2,4- and 3,4-dimethoxy substitutions in the phenethylamine moiety and the -F, -Cl, and -OCF3 substitutions in the ortho position of the phenyl ring of the N-benzyl moiety (34H-NBF, 34H-NBCl, 24H-NBOMe(F), and 34H-NBOMe(F)), assessing their behavioral and neurochemical effects following chronic 14 day treatment in adult zebrafish. While the novel tank test behavioral data indicate anxiolytic-like effects of 24H-NBOMe(F) and 34H-NBOMe(F), neurochemical analyses reveal reduced brain norepinephrine by all four drugs, and (except 34H-NBCl) - reduced dopamine and serotonin levels. We also found reduced turnover rates for all three brain monoamines but unaltered levels of their respective metabolites. Collectively, these findings further our understanding of complex central behavioral and neurochemical effects of chronically administered novel NBPEAs and highlight the potential of zebrafish as a model for preclinical screening of small psychoactive molecules.

Expression Pattern of Trace Amine-Associated Receptors during Differentiation of Human Pluripotent Stem Cells to Dopaminergic Neurons

Trace amine-associated receptors (TAARs), which were discovered only in 2001, are known to be involved in the regulation of a spectrum of neuronal processes and may play a role in the pathogenesis of a number of neuropsychiatric diseases, such as schizophrenia and others. We have previously shown that TAARs also have interconnections with the regulation of neurogenesis and, in particular, with the neurogenesis of dopamine neurons, but the exact mechanisms of this are still unknown. In our work we analyzed the expression of TAARs (TAAR1, TAAR2, TAAR5, TAAR6, TAAR8 and TAAR9) in cells from the human substantia nigra and ventral tegmental areas and in human pluripotent stem cells at consecutive stages of their differentiation to dopaminergic neurons, using RNA sequencing data from open databases, and TaqMan PCR data from the differentiation of human induced pluripotent stem cells in vitro. Detectable levels of TAARs expression were found in cells at the pluripotent stages, and the dynamic of their expression had a trend of increasing with the differentiation and maturation of dopamine neurons. The expression of several TAAR types (particularly TAAR5) was also found in human dopaminergic neuron-enriched zones in the midbrain. This is the first evidence of TAARs expression during neuronal differentiation, which can help to approach an understanding of the role of TAARs in neurogenesis.

Inhibition of PDE10A in a New Rat Model of Severe Dopamine Depletion Suggests New Approach to Non-Dopamine Parkinson's Disease Therapy

Parkinson's disease is the second most common neurodegenerative pathology. Due to the limitations of existing therapeutic approaches, novel anti-parkinsonian medicines with non-dopamine mechanisms of action are clearly needed. One of the promising pharmacological targets for anti-Parkinson drug development is phosphodiesterase (PDE) 10A. The stimulating motor effects of PDE10A inhibition were detected only under the conditions of partial dopamine depletion. The results raise the question of whether PDE10A inhibitors are able to restore locomotor activity when dopamine levels are very low. To address this issue, we (1) developed and validated the rat model of acute severe dopamine deficiency and (2) tested the action of PDE10A inhibitor MP-10 in this model. All experiments were performed in dopamine transporter knockout (DAT-KO) rats. A tyrosine hydroxylase inhibitor, α-Methyl-DL-tyrosine (αMPT), was used as an agent to cause extreme dopamine deficiency. In vivo tests included estimation of locomotor activity and catalepsy levels in the bar test. Additionally, we evaluated the tissue content of dopamine in brain samples by HPLC analysis. The acute administration of αMPT to DAT-KO rats caused severe depletion of dopamine, immobility, and catalepsy (Dopamine-Deficient DAT-KO (DDD) rats). As expected, treatment with the L-DOPA and carbidopa combination restored the motor functions of DDD rats. Strikingly, administration of MP-10 also fully reversed immobility and catalepsy in DDD rats. According to neurochemical studies, the action of MP-10, in contrast to L-DOPA + carbidopa, seems to be dopamine-independent. These observations indicate that targeting PDE10A may represent a new promising approach in the development of non-dopamine therapies for Parkinson's disease.

Discovery of Trace Amine Associated Receptor 1 (TAAR1) Agonist 2-(5-(4′-Chloro-[1,1′-biphenyl]-4-yl)-4H-1,2,4-triazol-3-yl)ethan-1-amine (LK00764) for the Treatment of Psychotic Disorders

A focused in-house library of about 1000 compounds comprising various heterocyclic motifs in combination with structural fragments similar to β-phenylethylamine or tyramine was screened for the agonistic activity towards trace amine-associated receptor 1 (TAAR1). The screening yielded two closely related hits displaying EC50 values in the upper submicromolar range. Extensive analog synthesis and testing for TAAR1 agonism in a BRET-based cellular assay identified compound 62 (LK00764) with EC₅₀ = 4.0 nM. The compound demonstrated notable efficacy in such schizophrenia-related in vivo tests as MK-801-induced hyperactivity and spontaneous activity in rats, locomotor hyperactivity of dopamine transporter knockout (DAT-KO) rats, and stress-induced hyperthermia (i.p. administration). Further preclinical studies are necessary to evaluate efficacy, safety and tolerability of this potent TAAR1 agonist for the potential development of this compound as a new pharmacotherapy option for schizophrenia and other psychiatric disorders.

Discovery and In Vivo Efficacy of Trace Amine-Associated Receptor 1 (TAAR1) Agonist 4-(2-Aminoethyl)-N-(3,5-dimethylphenyl)piperidine-1-carboxamide Hydrochloride (AP163) for the Treatment of Psychotic Disorders

Starting from a screening hit, a set of analogs was synthesized based on a 4-(2-aminoethyl)piperidine core not associated previously with trace amine-associated receptor 1 (TAAR1) modulation in the literature. Several structure–activity relationship generalizations have been drawn from the observed data, some of which were corroborated by molecular modeling against the crystal structure of TAAR1. The four most active compounds (EC₅₀ for TAAR1 agonistic activity ranging from 0.033 to 0.112 μM) were nominated for evaluation in vivo. The dopamine transporter knockout (DAT-KO) rat model of dopamine-dependent hyperlocomotion was used to evaluate compounds’ efficacy in vivo. Out of four compounds, only one compound (AP163) displayed a statistically significant and dose-dependent reduction in hyperlocomotion in DAT-KO rats. As such, compound AP163 represents a viable lead for further preclinical characterization as a potential novel treatment option for disorders associated with increased dopaminergic function, such as schizophrenia.

Acute behavioral and Neurochemical Effects of Novel N-Benzyl-2-Phenylethylamine Derivatives in Adult Zebrafish

Hallucinogenic drugs potently affect brain and behavior and have also recently emerged as potentially promising agents in pharmacotherapy. Complementing laboratory rodents, the zebrafish (Danio rerio) is a powerful animal model organism for screening neuroactive drugs, including hallucinogens. Here, we test a battery of ten novel N-benzyl-2-phenylethylamine (NBPEA) derivatives with the 2,4- and 3,4-dimethoxy substitutions in the phenethylamine moiety and the -OCH₃, -OCF₃, -F, -Cl, and -Br substitutions in the ortho position of the phenyl ring of the N-benzyl moiety, assessing their acute behavioral and neurochemical effects in the adult zebrafish. Overall, substitutions in the Overall, substitutions in the N-benzyl moiety modulate locomotion, and substitutions in the phenethylamine moiety alter zebrafish anxiety-like behavior, also affecting the brain serotonin and/or dopamine turnover. The 24H-NBOMe(F) and 34H-NBOMe(F) treatment also reduced zebrafish despair-like behavior. Computational analyses of zebrafish behavioral data by artificial intelligence identified several distinct clusters for these agents, including anxiogenic/hypolocomotor (24H-NBF, 24H-NBOMe, and 34H-NBF), behaviorally inert (34H-NBBr, 34H-NBCl, and 34H-NBOMe), anxiogenic/hallucinogenic-like (24H-NBBr, 24H-NBCl, and 24H-NBOMe(F)), and anxiolytic/hallucinogenic-like (34H-NBOMe(F)) drugs. Our computational analyses also revealed phenotypic similarity of the behavioral activity of some NBPEAs to that of selected conventional serotonergic and antiglutamatergic hallucinogens. In silico functional molecular activity modeling further supported the overlap of the drug targets for NBPEAs tested here and the conventional serotonergic and antiglutamatergic hallucinogens. Overall, these findings suggest potent neuroactive properties of several novel synthetic NBPEAs, detected in a sensitive in vivo vertebrate model system, the zebrafish, raising the possibility of their potential clinical use and abuse.

Trace Amine-Associated Receptor 2 Is Expressed in the Limbic Brain Areas and Is Involved in Dopamine Regulation and Adult Neurogenesis

Trace amines are a group of biogenic amines that are structurally and functionally close to classical monoamine neurotransmitters. Trace amine-associated receptors (TAARs) are emerging as promising targets for treating neuropsychiatric disorders. It has been documented that all TAARs, apart from TAAR1, function as olfactory receptors involved in sensing innate odors encoded by volatile amines. However, recently, brain expression and function of TAAR5 were also demonstrated. In this study, we assessed the behavior, brain neurochemistry, and electrophysiology changes in knock-out mice lacking Trace amine-associated receptor 2 (TAAR2) but expressing beta-Galactosidase mapping expression of TAAR2 receptors. As expected, we detected beta-Galactosidase staining in the glomerular layer of the olfactory bulb. However, we also found staining in the deeper layers of the olfactory bulb and several brain regions, including the hippocampus, cerebellum, cortex, raphe nuclei, hypothalamus, and habenula, indicating that TAAR2 receptors are not only expressed in the olfactory system but are also present in the limbic brain areas that receive olfactory input. In behavioral experiments, TAAR2 knock-out (TAAR2-KO) mice showed increased locomotor activity and less immobility in the forced swim test, with no changes in anxiety level. Furthermore, TAAR2-KO mice showed alterations in brain electrophysiological activity—particularly, decreased spectral power of the cortex and striatum in the 0, 9–20 Hz range. TAAR2-KO mice also had elevated tissue dopamine levels in the striatum and an increased dopaminergic neuron number in the Substantia Nigra. In addition, an increased brain-derived neurotrophic factor (BDNF) mRNA level in the striatum and Monoamine Oxidase B (MAO-B) mRNA level in the striatum and midbrain was found in TAAR2-KO mice. Importantly, TAAR2-KO mice demonstrated an increased neuroblast-like and proliferating cell number in the subventricular and subgranular zone, indicating increased adult neurogenesis. These data indicate that in addition to its role in the innate olfaction of volatile amines, TAAR2 is expressed in limbic brain areas and regulates the brain dopamine system, neuronal electrophysiological activity, and adult neurogenesis. These findings further corroborated observations in TAAR1-KO and TAAR5-KO mice, indicating common for TAAR family pattern of expression in limbic brain areas and role in regulating monoamine levels and adult neurogenesis, but with variable involvement of each subtype of TAAR receptors in these functions.

Effects of acute and chronic arecoline in adult zebrafish: Anxiolytic-like activity, elevated brain monoamines and the potential role of microglia

Arecoline is a naturally occurring psychoactive alkaloid with partial agonism at nicotinic and muscarinic acetylcholine receptors. Arecoline consumption is widespread, making it the fourth (after alcohol, nicotine and caffeine) most used substance by humans. However, the mechanisms of acute and chronic action of arecoline in-vivo remain poorly understood. Animal models are a valuable tool for CNS disease modeling and drug screening. Complementing rodent studies, the zebrafish (Danio rerio) emerges as a promising novel model organism for neuroscience research. Here, we assessed the effects of acute and chronic arecoline on adult zebrafish behavior and physiology. Overall, acute and chronic arecoline treatments produced overt anxiolytic-like behavior (without affecting general locomotor activity and whole-body cortisol levels), with similar effects also caused by areca nut water extracts. Acute arecoline at 10 mg/L disrupted shoaling, increased social preference, elevated brain norepinephrine and serotonin levels and reduced serotonin turnover. Acute arecoline also upregulated early protooncogenes c-fos and c-jun in the brain, whereas chronic treatment with 1 mg/L elevated brain expression of microglia-specific biomarker genes egr2 and ym1 (thus, implicating microglial mechanisms in potential effects of long-term arecoline use). Finally, acute 2-h discontinuation of chronic arecoline treatment evoked withdrawal-like anxiogenic behavior in zebrafish. In general, these findings support high sensitivity of zebrafish screens to arecoline and related compounds, and reinforce the growing utility of zebrafish for probing molecular mechanisms of CNS drugs. Our study also suggests that novel anxiolytic drugs can eventually be developed based on arecoline-like molecules, whose integrative mechanisms of CNS action may involve monoaminergic and neuro-immune modulation.

[Influence of the DAT gene knockout on exchange of essential and toxic trace elements in rats]

The maintenance of energy homeostasis of the body according to modern data is carried out with the active participation of dopaminergic neurons of the central nervous system. The synthesis and metabolism of dopamine (DA) occurs both in the brain and in peripheral tissues. Violation of the synthesis and metabolism of DA is considered as a link in the vicious cycle which it formed during the development of diet-induced obesity. According to modern data, a number of essential and toxic trace elements, such as Cd, Al, As, Mn, Fe, Cu, Zn, are actively involved in the exchange of DA in the brain and peripheral organs and tissues. One way to assess this relationship is to compare changes in the microelement status of the organism when consuming hypercaloric diets in animals with normal and impaired DA transport. The latter can be animals with a knockout of the DAT transporter gene, which performs DA reabsorption with subsequent storage in the composition of secretory granules. The aim is a comparative study of the content of a number of essential and toxic elements in the brain, liver, and kidneys of rats that differ in the allelic variants of the DAT gene fed balanced diet and the diet with an excess of energy value. Material and methods. The study was carried out on 30 male rats of the DAT-KO knockout line (homozygotes DAT-/- and heterozygotes DAT+/-), 8-10 weeks old, and 13 males rats of the outbred Wistar line (DAT+/+) of the same age. For 62 days the animals (6 groups) received a semi-synthetic diet containing essential elements in the salt mixture or a similar high-fat-highcarbohydrate diet (HFCD) with 30% fat and 20% fructose solution instead of drinking water. The content of 16 trace elements (Fe, Mg, Cu, Mn, Co, Se, Zn, Cr, V, Cs, Ag, Al, Cd, As, Pb, Ni) were determined by inductively coupled plasma mass spectrometry in the liver, kidneys, and brain of rats with a knockout of the dopamine DAT transporter gene: homozygotes (DAT -/-) and heterozygotes (DAT+/-), as well as wild-type rats (DAT+/+) of the Wistar strain. Results and discussion. In the liver, DAT knockout led to an increase in the content of As, Cd, Co, and Cs and a decrease in Fe; in the kidneys - to an increase in the levels of Pb, As, Cd and Se, in the brain - an increase in the content of most of the studied trace elements, including Pb, As, Cs, Al and Cu. Conclusion. Against the background of consumption of HFCD, the effect of DAT knockout on the content of a number of elements was more pronounced compared with the consumption of the control diet. The revealed changes in the trace element content in DAT knockout rats are considered in terms of the effect of DA metabolism in the central nervous system and in peripheral tissues on the status of trace elements.

Increased dopamine transmission and adult neurogenesis in trace amine-associated receptor 5 (TAAR5) knockout mice

Trace amine-associated receptors (TAARs) are a class of sensory G protein-coupled receptors that detect biogenic amines, products of decarboxylation of amino acids. The majority of TAARs (TAAR2-TAAR9) have been described mainly in the olfactory epithelium and considered to be olfactory receptors sensing innate odors. However, there is recent evidence that one of the members of this family, TAAR5, is expressed also in the limbic brain areas receiving projection from the olfactory system and involved in the regulation of emotions. In this study, we further characterized a mouse line lacking TAAR5 (TAAR5 knockout, TAAR5-KO mice) that express beta-galactosidase mapping TAAR5 expression. We found that in TAAR5-KO mice the number of dopamine neurons, the striatal levels of dopamine and its metabolites, as well as striatal levels of GDNF mRNA, are elevated indicating a potential increase in dopamine neuron proliferation. Furthermore, an analysis of TAAR5 beta-galactosidase expression revealed that TAAR5 is present in the major neurogenic areas of the brain such as the subventricular zone (SVZ), the subgranular zone (SGZ) and the less characterized potentially neurogenic zone surrounding the 3rd ventricle. Direct analysis of neurogenesis by using specific markers doublecortin (DCX) and proliferating cell nuclear antigen (PCNA) revealed at least 2-fold increase in the number of proliferating neurons in the SVZ and SGZ of TAAR5-KO mice, but no such markers were detected in mutant or control mice in the areas surrounding the 3rd ventricle. These observations indicate that TAAR5 involved not only in regulation of emotional status but also adult neurogenesis and dopamine transmission. Thus, future TAAR5 antagonists may exert not only antidepressant and/or anxiolytic action but may also provide new treatment opportunity for neurodegenerative disorders such as Parkinson's disease.

Trace Amine-Associated Receptor 5 Provides Olfactory Input Into Limbic Brain Areas and Modulates Emotional Behaviors and Serotonin Transmission

Trace amine-associated receptors (TAARs) are a class of G-protein-coupled receptors found in mammals. While TAAR1 is expressed in several brain regions, all the other TAARs have been described mainly in the olfactory epithelium and the glomerular layer of the olfactory bulb and are believed to serve as a new class of olfactory receptors sensing innate odors. However, there is evidence that TAAR5 could play a role also in the central nervous system. In this study, we characterized a mouse line lacking TAAR5 (TAAR5 knockout, TAAR5-KO) expressing beta-galactosidase mapping TAAR5 expression. We found that TAAR5 is expressed not only in the glomerular layer in the olfactory bulb but also in deeper layers projecting to the limbic brain olfactory circuitry with prominent expression in numerous limbic brain regions, such as the anterior olfactory nucleus, the olfactory tubercle, the orbitofrontal cortex (OFC), the amygdala, the hippocampus, the piriform cortex, the entorhinal cortex, the nucleus accumbens, and the thalamic and hypothalamic nuclei. TAAR5-KO mice did not show gross developmental abnormalities but demonstrated less anxiety- and depressive-like behavior in several behavioral tests. TAAR5-KO mice also showed significant decreases in the tissue levels of serotonin and its metabolite in several brain areas and were more sensitive to the hypothermic action of serotonin 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propilamino)tetralin (8-OH-DPAT). These observations indicate that TAAR5 is not just innate odor-sensing olfactory receptor but also serves to provide olfactory input into limbic brain areas to regulate emotional behaviors likely via modulation of the serotonin system. Thus, anxiolytic and/or antidepressant action of future TAAR5 antagonists could be predicted. In general, "olfactory" TAAR-mediated brain circuitry may represent a previously unappreciated neurotransmitter system involved in the transmission of innate odors into emotional behavioral responses.

The zebrafish tail immobilization (ZTI) test as a new tool to assess stress-related behavior and a potential screen for drugs affecting despair-like states

BACKGROUND

Affective disorders, especially depression and anxiety, are highly prevalent, debilitating mental illnesses. Animal experimental models are a valuable tool in translational affective neuroscience research. A hallmark phenotype of clinical and experimental depression, the learned helplessness, has become a key target for 'behavioral despair'-based animal models of depression. The zebrafish (Danio rerio) has recently emerged as a promising novel organism for affective disease modeling and CNS drug screening. Despite being widely used to assess stress and anxiety-like behaviors, there are presently no clear-cut despair-like models in zebrafish.

NEW METHOD

Here, we introduce a novel behavioral paradigm, the zebrafish tail immobilization (ZTI) test, as a potential tool to assess zebrafish despair-like behavior. Conceptually similar to rodent 'despair' models, the ZTI protocol involves immobilizing the caudal half of the fish body for 5 min, leaving the cranial part to move freely, suspended vertically in a small beaker with water.

RESULTS

To validate this model, we used exposure to low-voltage electric shock, alarm pheromone, selected antidepressants (sertraline and amitriptyline) and an anxiolytic drug benzodiazepine (phenazepam), assessing the number of mobility episodes, time spent 'moving', total distance moved and other activity measures of the cranial part of the body, using video-tracking. Both electric shock and alarm pheromone decreased zebrafish activity in this test, antidepressants increased it, and phenazepam was inactive. Furthermore, a 5-min ZTI exposure increased serotonin turnover, elevating the 5-hydroxyindoleacetic acid/serotonin ratio in zebrafish brain, while electric shock prior to ZTI elevated both this and the 3,4-dihydroxyphenylacetic acid/dopamine ratios. In contrast, preexposure to antidepressants sertraline and amitriptyline lowered both ratios, compared to the ZTI test-exposed fish.

COMPARISON WITH EXISTINGMETHOD(S)

The ZTI test is the first despair-like experimental model in zebrafish.

CONCLUSIONS

Collectively, this study suggests the ZTI test as a potentially useful protocol to assess stress-/despair-related behaviors, potentially relevant to CNS drug screening and behavioral phenotyping of zebrafish.

Dopamine transporter mutant animals: a translational perspective

The dopamine transporter (DAT) plays an important homeostatic role in the control of both the extracellular and intraneuronal concentrations of dopamine, thereby providing effective control over activity of dopaminergic transmission. Since brain dopamine is known to be involved in numerous neuropsychiatric disorders, investigations using mice with genetically altered DAT function and thus intensity of dopamine-mediated signaling have provided numerous insights into the pathology of these disorders and novel pathological mechanisms that could be targeted to provide new therapeutic approaches for these disorders. In this brief overview, we discuss recent investigations involving animals with genetically altered DAT function, particularly focusing on translational studies providing new insights into pathology and pharmacology of dopamine-related disorders. Perspective applications of these and newly developed models of DAT dysfunction are also discussed.

[Acute myocardial infarction in elderly and senile patients: epidemiology study according to the who program "registry of acute myocardial infarction]

The article presents results of the epidemiology study of acute myocardial infarction (AMI) among permanent Tomsk residents older than 60 years. The study was conducted in 2008-2009 according to the WHO program «Registry of Acute Myocardial Infarction». Data demonstrated that morbidity and mortality from AMI was higher in the above mentioned age group than in younger population. Rates of morbidity and mortality in men exceeded those in women in all age groups except population older than 80 years. The study showed high in-hospital lethality caused by high death rates in patients 60 years of age and older who were treated in non-specialized hospitals. Authors conclude that the severity of epidemiology situation with AMI is determined by the frequency of this pathology in population older than 60 years suggesting the necessity of change in the strategy of system development of medical care for AMI patients with focus on the older age groups.

[Factors determining application activity for and satisfaction with medical care among able-bodied population of closed industrial city]

According to a poll results, nearly 16.5% of questioned able-bodied inhabitants of industrial city mentioned unsatisfactory health state of self, with main reasons of negative environmental influence and low availability of quality medical care. Most respondents (81.1%) are characterized by poor medical activity. Over a quarter of the questioned (25.7%) are dissatisfied with provided medical care. The main factors determining medical activity and satisfaction with medical care are age, sex, employment place and income level.

[ACE and AGTR1 genes polymorphisms in left ventricular hypertrophy pathogenesis in humans]

The role of A2350G polymorphism in exon 17 of the ACE gene and A1166C - in 3'-UTR of the AGTR1 in the pathogenesis of left ventricular hypertrophy was studied in patients with essential hypertension (EH) and arterial hypertension combined with diabetes mellitus type 2 (AH + DM2). Patients with EH and AH + DM2 did not differ from the control sample of healthy individuals by allele or genotype frequencies. However, an association of both polymorphisms with LVH was detected in EH patients. The frequency of 1166C allele was higher in patients with LVH (33.6% vs 20.7% without LVH). A1166C polymorphism determined the magnitude of left ventricular mass index (LVMI) in EH patients as well (p = 0.007). 2350G allele frequency of the ACE gene was in 1.5, and GG genotype--in 3.5-fold higher in EH patients with LVH, as compared without LVH. LVMI was significantly higher in patients with GG genotype as compared with heterozygotes and AA homozygotes (p = 0.002). Thus the presence of 1166C allele of AGTR1 and 2350G allele of ACE can be considered as predisposing factors for LVH development in EH. In contrast, association of studied polymorphisms with presence or LVH degree was not detected in patients with arterial hypertension combined with DM2. This may indicate another structure of genetic component of predisposition to LVH in different causes.

[Clinical Efficacy of Combination Therapy With Trimetazidine and Angiotensin Converting Enzyme Inhibitors in Patients With Hypertension and Ischemic Heart Disease Associated With Type II Diabetes]

AIM

To assess in a randomized open study effect of 12-15 week use of angiotensin converting enzyme inhibitors (ACEI) with and without trimetazidine on myocardial perfusion reserve in patients with ischemic heart disease (IHD) and/or hypertension associated with type II diabetes.

MATERIAL

Patients (n=69) receiving long term ACEI therapy with transient myocardial perfusion defects during dipyridamole stress test.

METHODS

Control patients (n=29, including 15 with IHD) continued to receive an ACEI, while in trimetazidine group (n=40, including 21 IHD patients) trimetazidine (60 mg/day) was added to ACEI. Single photon emission computer tomography with (199)Thallium Chloride was used for measurement of myocardial perfusion reserve. Changes of physical working capacity, intracardiac hemodynamics and glycemia were studied only in trimetazidine group.

RESULTS AND CONCLUSION

Significant 52% (mean) decrease (32.5% in IHD patients) of perfusion defects and acceleration on total clearance of Tl-199 were registered in trimetazidine group while no considerable changes of myocardial perfusion were revealed in control group. Most substantial changes of myocardial blood flow reserve occurred in patients with moderate alterations of left ventricular diastolic filling, and among IHD patients - in those without cardiac dilatation and pronounced diastolic left ventricular dysfunction. Significant increase (45.9 and 23.9% in patients with and without IHD, respectively) of total work performed during bicycle exercise was registered in trimetazidine treated patients. In IHD patients decline of initially elevated intramyocardial tension was also observed.

[Coronary flow vasodilator reserve in patients with type 2 diabetes mellitus-associated arterial hypertension]

The coronary flow vasodilator reserve (CFVR) in the proximal segment of the anterior descending coronary artery was studied in 50 patients with diabetes mellitus (DM), by Doppler study via transesophageal approach. Group 1 included 39 patients with DM concurrent with Stages 1-2 arterial hypertension (AH), of them 14 patients were documented as having coronary heart disease (CHD) in the presence of coronary atherosclerosis (Subgroup 1A) and CHD was excluded in the remaining 25 patients (Subgroup 1B). Group comprised 11 patients with normal blood pressure (BP). For comparison, 6 healthy individuals were examined. CFVR was calculated as a ratio of the peak diastolic coronary flow (CF) velocity during infusion of dipyridamole (0.56 mg/kg) to the baseline CF. CDVR was significantly decreased as compared with the controls (2.07 +/- 0.73 in Subgroup 1A, 2.15 +/- 0.67 in subgroup 1B, 1.78 +/- 0.33 in Group 2, and 3.68 +/- 0.26 in the controls), this decrease being due to low CF velocities in hyperemia in the majority of patients in Subgroup 1A and Group 2 and to higher baseline CF velocity in most patients from Subgroup 1B. In Group 1 patients, CFVR was not linear with age, the duration of the disease, BP and HbA1 levels, but it was related to the carotid distensibility coefficient (rho = 0.60, p = 0.004) and to the blood level of total cholesterol (rho = -0.43, p = 0.0107). In Group 2 patients, the least CF velocities in the presence of vasodilatation were detectable in older patients and in patients with hypercholesterolemia. An all the patients with left ventricular hypertrophy (LVH) had decreased CFVR whose values with the myocardial mass index above 130 g/m2 were significantly less than those in the absence of LVH. Thus, the limited reserve of coronary vasodilatation was detectable in patients with DM irrespective of BP levels and the status of epicardial arteries and it was most pronounced in LVH and hypercholesterolemia. The impaired elastic properties of peripheral arteries in the presence of cholesterolemia may be regarded as a marker of the low reserve of coronary vasodilatation in patients with DM concurrent with AH.

[Polymorphic markers of GNB3 (C825T), AGTR1 (A1166C) and ACE (A2350G and I/D) genes in patients with arterial hypertension combined with diabetes mellitus type 2]

AIM

To elicit correlations of polymorphic markers of GNB3 (C825T), AGTR1 (A1166C), ACE (A2350G and I/D) genes with arterial pressure, left ventricular hypertrophy (LVH) and blood concentrations of proinflammatory cytokines in hypertensive patients with diabetes mellitus type 2 (DM2).

MATERIAL AND METHODS

Clinical parameters (24-h arterial pressure profile, echocardiographic findings, immunoenzymes level) were studied in 89 hypertensive patients with DM2. These patients had different genotypes by the studied allele variants of the genes determined by polymerase chain reaction.

RESULTS

Polymorphism of A1166C gene of type 1 vascular receptor of angiotensin II (AGTR1) contributes to formation of arterial hypertension (AH) signs diversity in DM2 patients. GNB3, a gene C825T polymorphic marker, showed a correlation with diastolic arterial pressure but this variant of the gene locus is not associated with LVH. However, G-allele of ACE gene contributes much to appearance of this pathological sign. Mean values of IL-1beta and TNF-alpha as well as the presence of LVH depended on genotypes by ACE gene (polymorphism I/D).

CONCLUSION

Polymorphic markers of ACE and GNB3 candidate genes influence clinical diversity of pathological signs in DM2 patients through modification of AH and LVH severity and the level of proinflammatory cytokines.

[Effect of long term therapy with captopril on dopplerographic parameters of intrarenal blood flow and renal function in patients with hypertension and diabetes]

Effect of 9-12 month treatment with captopril on dopplerographic parameters of intrarenal blood flow and renal function was studied in 30 hypertensive diabetics without clinical signs of nephroangiopathy. There was an interrelationship between strict blood pressure (BP) control (average 24-hour BP below 135/83) and improvement of parameters of intrarenal hemodynamics. BP normalization and most pronounced positive changes of renal perfusion during therapy with captopril were achieved in patients with mild hypertension and initially high intrarenal resistance yet at the stage of normo- or microalbuminuria. In moderate hypertension with microalbuminuria treatment with captopril was associated with stabilization of parameters of renal blood flow and rate of 24-hour albumin excretion at their initial level despite less strict control of BP and unsatisfactory compensation of diabetes. BP response to captopril in patients with hypertension and diabetes was related to initial state of intrarenal hemodynamics. In patients with mild hypertension indexes of resistance of renal and intrarenal arteries could be used for prediction of sensitivity to antihypertensive action of captopril.

Contrasting effects of IG20 and its splice isoforms, MADD and DENN-SV, on tumor necrosis factor alpha-induced apoptosis and activation of caspase-8 and -3

We identified a novel cDNA (IG20) that is homologous to cDNAs encoding a protein differentially expressed in normal and neoplastic cells (DENN-SV) and human MADD (MAPK-activating death domain-containing protein). Furthermore, we show that the above variants most likely result from alternative splicing of a single gene. Functional analyses of these variants in permanently transfected HeLa cells revealed that IG20 and DENN-SV render them more susceptible or resistant to tumor necrosis factor alpha (TNF-alpha)-induced apoptosis, respectively. All variants tested could interact with TNF receptor 1 and activate ERK and nuclear factor kappaB. However, relative to control cells, only cells expressing IG20 showed enhanced TNF-alpha-induced activation of caspase-8 and -3, whereas cells expressing DENN-SV showed either reduced or no caspase activation. Transfection of these cells with a cDNA encoding CrmA maximally inhibited apoptosis in HeLa-IG20 cells. Our results show that IG20 can promote TNF-alpha-induced apoptosis and activation of caspase-8 and -3 and suggest that it may play a novel role in the regulation of the pleiotropic effects of TNF-alpha through alternative splicing.

[Comparison of the effects of thyroliberin and ACTH4-7 PGP on the learning of rats during the solving of spatial orientation tasks]

The influence of TRH (100 micrograms/kg) and ACTH4-7 Pro-Gly-Pro (15 micrograms/kg and 25 micrograms/kg) involved an acceleration of the spatial learning on the 12-arm radial maze and on T-maze in rats; an increase in the number of correct choice after short (5-10 min) retention interval; and affected the working and reference spatial memory in the test of reinforced place performance. The effects of the TRH and ACTH4-7 Pro-Gly-Pro did not interfere with one another.

[Early and late changes in potassium transport during the start of proliferation in CHO cell cultures. The action of serum, isoproterenol, propranolol and theophylline]

The stimulation of DNA synthesis by serum is accompanied by early (30 minutes) and late (2-8 hours) increase in ouabain-sensitive rubidium (potassium) influx and the elevation of intracellular potassium content from 0.5-0.6 to 0.7-0.8 mmole per gram protein in CHO-K1 cells. Isoproterenol alone induces the transient increase both in potassium influx via Na,K-ATPase and in potassium efflux without any effect on intracellular potassium content and cell proliferation. Isoproterenol acts synergistically with serum in eliciting the early and late changes in potassium transport and in stimulating G1----S transition. The combination of serum and theophylline produces a rapid increase in potassium influx, however, it does not stimulate DNA synthesis and does not induce any later increase in intracellular potassium content. It is concluded that early and late activation of Na,K-ATPase by mitogens can be dissociated; the Na,K-ATPase activation is involved in mitogenic response when producing the sustained potassium influx and the elevation of intracellular potassium content during G1----S transition.

[Cation transport and content in serum-stimulated CHO-773 cells. III. The intracellular content of sodium, calcium and magnesium]

Intracellular sodium, calcium, and magnesium content as well as lithium influx have been examined in serum-stimulated CHO cultures using flame-emission technique. Intracellular sodium and lithium influx does not change during the G1----S transition, they increase by 1.3-2 times in the late S and in mitosis. In stationary cultures of CHO cells cellular magnesium is about 50-60 mumole/gr protein; its content increases in 2-3 hours after serum addition and remains constant during the G1----S transition. In stationary cultures of CHO cells cellular calcium is about 20 mumole/gr protein and it increases by 1.5-2 times in the late G1 and S phases. It is concluded that alterations of ion transport accompany not only the early cell response to mitogen but also the G1----S transition.

[Cation transport and content in serum-stimulated CHO-773 cells. I. Rapid changes in rubidium and lithium influxes and intracellular sodium content]

The cultures of Chinese hamster ovary cells (CHO-K1 clone 773) can be brought to the stationary state with most of cellular populations in G1 phase by growing continuously for 4 days up to the cultural density (10-12) X 10(4) cells/cm2. Upon introduction of fresh Eagle medium with 10% calf serum the cells progress from G1 to S phase for 7-9 hours. It is shown that within the first minutes of serum addition ouabain-sensitive rubidium influx increases, however, lithium influx, which serves a test for passive sodium pathways in the membrane, increases or does not change. No correlation was found between the rubidium influx and intracellular sodium changes, induced by serum. From comparative studies of ouabain-sensitive rubidium influx, lithium influx and intracellular sodium content it is concluded that the increase in intracellular sodium is not responsible for serum-induced Na,K-ATPase activation.

[Karyotypic characteristics of the Chinese hamster cell line CHO-K1 resistant to colchicine]

Karyological analysis was made of G-banded chromosomes in the cells of three independent CHO-K1 clones stably resistant to colchicine (Clch) selected for resistance to Clch at the concentration 0.1 mkg/ml (the first step of selection), and of one clone with higher but unstable level of resistance (2 mkg/ml--the second level of resistance). The results obtained revealed a morphological instability of the P-shoulder of chromosome Z6: more often an additional genetical material (AGM) at the distal end (Z6+), or rarely deletions (Z6-). In cells of the stable resistant clones of the first step of selection the length of AGM and their morphological structures were shown to be constant, but differed among the clones. In cells of the higher resistant unstable clone the length of AGM and their morphological structure were different in different cells within the clone. The AGMs in the Clch-resistant cells are discussed in terms of possible amplification of gene(s) responsible for the Clch resistance. In the cell population of clone selected for the resistance to 2 mkg/ml of Clch the frequency of rearranged chromosomes was shown to increase. In cells of all the analysed resistant clones the chromosome Z16 was found to lose its p-shoulder.

[Isoproterenol stimulation of the repair of single-stranded DNA breaks in Chinese hamster cells induced by gamma irradiation]

The action of the increased intracellular content of adenosine monophosphate (cAMP) in CHO-K1 cells (clones 773 and ADr112eb), treated with isoproterenol, on gamma-induced DNA single-strand breaks repair has been investigated. The hormonal treatment stimulates gamma-induced (180 Gr) DNA single-strand repair during the post-irradiation incubation (45 min) by 75 +/- 16%. The results show the involvement of the cAMP system in radiosensitivity of cultured mammalian cells and in regulation of cellular mechanisms of DNA repair.

[Genetic characteristics of Chinese hamster cell resistance to colchicine, actinomycin D and ethidium bromide]

We have tried to study genetics of Chinese hamster cellular drug resistance to colchicine, actinomycin D and ethidium bromide. Resistant variants arising at a frequency 10(-5) to 10(-7) were selected from a sensitive population. Pretreatment with MNNG increased this frequency 106, 9-15, 12-26 times for colchicine, actinomycin D and ethidium bromide, respectively. Fluctuation test analysis allows to suppose that phenotypic expression of drug resistance is genetically determined and resulted from random genetical events. Significant values of particular correlation coefficients for selecting resistant variants in a set of independently originated subpopulations suggest the genetical identity of the majority of variants selected by colchicine and actinomycin D. At the same time, the significant portion of colchicine-resistant cells may be selected using ethidium bromide. It is not unlikely that under above experimental conditions, each selective agent reveals genetically different resistant variants. The possible genetic mechanisms of resistance to the drugs used are discussed.

[Cyclic adenosine monophosphate content and its regulatory characteristics in Chinese hamster cells with genetically determined changes in the cell surface]

The intra- and extracellular concentrations of cyclic adenosine monophosphate (cAMP) in cell line CHO-K1, sensitive (clone 773) and resistant to cytotoxic action of ethidium bromide (EBr), colchicine (Cr) and actinomycin D (ADr), as well as the amount of cAMP in response to isoproterenol, 10% serum and ethidium bromide (EB) in these cells were studied. The increased level of cAMP in EBr- and, Cr-cells, and the decreased one--in ADr cells was found as compared with sensitive cells. The amount of cAMP extruded in the surrounding medium was lower for EBr- and Cr-cells and higher for ADr-cells, in comparison with sensitive cells. All the variants of resistant cells were characterized by a less intensive but a longer reaction for isoproterenol, as compared with sensitive cells. In all the investigated variants 10% serum induced a remarkable increase in the intracellular cAMP by the 2nd hour after their insignificant decrease. 1 mcg/ml concentration of EBr increased intracellular cAMP only in 773-cells. The rules changing the cAMP level to isoproterenol and EB2; are determined by differences in reaction of adenylate cyclase, as it has been demonstrated for the 773- and EBr-cells.

[Isolation and characteristics of Chinese hamster cells resistant to colchicine]

Several ClchR clones of CHO-K1 have been isolated by a single- and multistep selection. They are distinct from each other both in the level of colchicine resistance and in the phenotypic stability of this feature. Fluctuation tests showed that the generation of drug resistant variants in the wild type population was random and did not depend on the action of selective agent. The rate of spontaneous occurrence of these variants was approximatley 1.79 x 10(-6) per cell per generation. Treatment with MNNG enhanced the frequency of ClchR variants by 100 fold. Cytotoxic effect of Clch on resistant cells has been potentiated by non-ionic detergent Tween 80. All the stable resistant clones appeared to be cross resistant to unrelated drugs such as actinomycin D, ethydium bromide and aminopterine . These two observations allow to suggest the alteration of membrane permeability as a mechanism of resistance to Clch . Genetical mechanisms of Clch -resistance of cells are discussed.