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Pharmacological Research Apr 2018The intestine is one of the most important sites for the metabolism of several xenobiotic compounds. In addition to intestinal drug-metabolizing enzymes and drug... (Review)
Review
The intestine is one of the most important sites for the metabolism of several xenobiotic compounds. In addition to intestinal drug-metabolizing enzymes and drug transporters, gut microbial enzymes modulate the biotransformation of orally administered drugs in the gastrointestinal tract. Antihypertensive drugs such as amlodipine and nifedipine could be metabolized by gut microbial enzymes, which may influence drug absorption, leading to changes in pharmacological potency of the drug and eventual failure of the appropriate blood pressure control or unexpected side effects. This may suggest that there are additional mechanisms that can alter the therapeutic efficacy of antihypertensive drugs, especially in certain pathological conditions of the gastrointestinal tract or with concomitant use of substances such as antibiotics and probiotics that might alter the gut microbial composition. This review describes the metabolism of antihypertensive drugs by hepatic and intestinal microbial enzymes in an attempt to understand the potential effects of gut microbiota on their pharmacokinetics.
Topics: Animals; Antihypertensive Agents; Biological Transport; Biotransformation; Gastrointestinal Microbiome; Humans
PubMed: 29391236
DOI: 10.1016/j.phrs.2018.01.019 -
Current Neuropharmacology 2019Genetic polymorphisms of drug metabolizing enzymes can substantially modify the pharmacokinetics of a drug and eventually its efficacy or toxicity; however, inferring a... (Review)
Review
BACKGROUND
Genetic polymorphisms of drug metabolizing enzymes can substantially modify the pharmacokinetics of a drug and eventually its efficacy or toxicity; however, inferring a patient's drug metabolizing capacity merely from his or her genotype can lead to false prediction. Non-genetic host factors (age, sex, disease states) and environmental factors (nutrition, comedication) can transiently alter the enzyme expression and activities resulting in genotypephenotype mismatch. Although valproic acid is a well-tolerated anticonvulsant, pediatric patients are particularly vulnerable to valproate injury that can be partly attributed to the age-related differences in metabolic pathways.
METHODS
CYP2C9 mediated oxidation of valproate, which is the minor metabolic pathway in adults, appears to become the principal route in children. Genetic and non-genetic variations in CYP2C9 activity can result in significant inter- and intra-individual differences in valproate pharmacokinetics and valproate induced adverse reactions.
RESULTS
The loss-of-function alleles, CYP2C9*2 or CYP2C9*3, display significant reduction in valproate metabolism in children; furthermore, low CYP2C9 expression in patients with CYP2C9*1/*1 genotype also leads to a decrease in valproate metabolizing capacity. Due to phenoconversion, the homozygous wild genotype, expected to be translated to CYP2C9 enzyme with normal activity, is transiently switched into poor (or extensive) metabolizer phenotype.
CONCLUSION
Novel strategy for valproate therapy adjusted to CYP2C9-status (CYP2C9 genotype and CYP2C9 expression) is strongly recommended in childhood. The early knowledge of pediatric patients' CYP2C9-status facilitates the optimization of valproate dosing which contributes to the avoidance of misdosing induced adverse reactions, such as abnormal blood levels of ammonia and alkaline phosphatase, and improves the safety of children's anticonvulsant therapy.
Topics: Adult; Age Factors; Anticonvulsants; Biosynthetic Pathways; Child; Cytochrome P-450 CYP2C9; Epilepsy; Genotype; Humans; Phenotype; Polymorphism, Genetic; Valproic Acid
PubMed: 29119932
DOI: 10.2174/1570159X15666171109143654 -
Neuroscience and Biobehavioral Reviews Sep 2014Most drugs are metabolized in the liver by cytochromes P450 (CYPs). Stress can modify CYP-catalyzed drug metabolism and subsequently, the pharmacokinetic profile of a... (Review)
Review
Most drugs are metabolized in the liver by cytochromes P450 (CYPs). Stress can modify CYP-catalyzed drug metabolism and subsequently, the pharmacokinetic profile of a drug. Current evidence demonstrates a gene-, stress- and species-specific interference in stress-mediated regulation of genes encoding the major drug-metabolizing CYP isozymes. Stress-induced up-regulation of CYPs that metabolize the majority of prescribed drugs can result in their increased metabolism and consequently, in failure of pharmacotherapy. In contrast, stress-induced down-regulation of CYP isozymes, including CYP2E1 and CYP2B1/2, potentially reduces metabolism of several toxicants and specific drugs-substrates resulting in increased levels and altered toxicity. The primary stress effectors, the adrenergic receptor-linked pathways and glucocorticoids, play primary and distinct roles in stress-mediated regulation of CYPs. Evidence demonstrates that stress regulates major drug metabolizing CYP isozymes, suggesting that stress should be considered to ensure pharmacotherapy efficacy and minimize drug toxicity. A detailed understanding of the molecular events underlying the stress-dependent regulation of drug metabolizing CYPs is crucial both for the design of new drugs and for physiology-based pharmacokinetic and pharmacodynamic modeling.
Topics: Animals; Cytochrome P-450 Enzyme System; Humans; Pharmacokinetics; Stress, Psychological
PubMed: 24877684
DOI: 10.1016/j.neubiorev.2014.05.011 -
The Science of the Total Environment Dec 2023Methylmercury (MeHg) readily accumulates in aquatic organisms while transferring and amplifying in the aquatic food chains. This study firstly explores the in vivo...
Methylmercury (MeHg) readily accumulates in aquatic organisms while transferring and amplifying in the aquatic food chains. This study firstly explores the in vivo accumulation sites and metabolic regulation of MeHg in the rotifer Brachionus plicatilis by aggregation-induced emission fluorogen (AIEgen) and metabolomics. Fluorescent image analysis by AIEgen showed that MeHg in B. plicatilis mainly occured in the ciliary corona, esophagus, mastax, stomach and intestine in the direct absorption group. In the other group, where B. plicatilis were indirectly supplied with MeHg via food intake, the accumulation of MeHg in the rotifer occurred in the ciliary corona, various digestive organs, and the pedal gland. However, the MeHg accumulated in the rotifer is difficult to metabolize outside the body. Metabolomics analysis showed that the significant enrichment of ABC transporters was induced by the direct exposure of rotifers to dissolved MeHg. In contrast, exposure of rotifers to MeHg via food intake appeared to influence carbon, galactose, alanine, aspartate and glutamate metabolisms. Besides, the disturbed biological pathways such as histidine metabolism, beta-alanine metabolism and pantothenate and CoA biosynthesis in rotifers may be associated with L-aspartic acid upregulation in the feeding group. The significant enrichment of ABC transporters and carbon metabolism in rotifers may be related to the accumulation of MeHg in the intestine of rotifers. In both pathways of MeHg exposure, the arginine biosynthesis and metabolism of rotifers were disturbed, which may support the hypothesis that rotifers produce more energy to resist MeHg toxicity. This study provides new insight into the accumulation and toxicity mechanisms of MeHg on marine invertebrates from the macro and micro perspectives.
Topics: Animals; Methylmercury Compounds; Rotifera; Metabolic Networks and Pathways; ATP-Binding Cassette Transporters; Carbon
PubMed: 37709075
DOI: 10.1016/j.scitotenv.2023.167063 -
Current Opinion in Neurobiology Aug 2023Brain computation is metabolically expensive and requires the supply of significant amounts of energy. Mitochondria are highly specialized organelles whose main function... (Review)
Review
Brain computation is metabolically expensive and requires the supply of significant amounts of energy. Mitochondria are highly specialized organelles whose main function is to generate cellular energy. Due to their complex morphologies, neurons are especially dependent on a set of tools necessary to regulate mitochondrial function locally in order to match energy provision with local demands. By regulating mitochondrial transport, neurons control the local availability of mitochondrial mass in response to changes in synaptic activity. Neurons also modulate mitochondrial dynamics locally to adjust metabolic efficiency with energetic demand. Additionally, neurons remove inefficient mitochondria through mitophagy. Neurons coordinate these processes through signalling pathways that couple energetic expenditure with energy availability. When these mechanisms fail, neurons can no longer support brain function giving rise to neuropathological states like metabolic syndromes or neurodegeneration.
Topics: Neurons; Mitochondria; Biological Transport; Signal Transduction; Mitochondrial Dynamics; Energy Metabolism
PubMed: 37392672
DOI: 10.1016/j.conb.2023.102747 -
Journal of Personalized Medicine Aug 2022Genetic variability in CYP2C19 may be associated with both lack of efficacy and toxicity of drugs due to its different metabolic status based on the presence of... (Review)
Review
Genetic variability in CYP2C19 may be associated with both lack of efficacy and toxicity of drugs due to its different metabolic status based on the presence of particular alleles. This literature review summarizes current knowledge relative to the association or treatment adaptation based on genetics in a pediatric population receiving drugs metabolized by CYP2C19, such as voriconazole, antidepressants, clopidogrel and proton pump inhibitors. Additionally, we also presented one of the approaches that we developed for detection of variant alleles in the CYP2C19 gene. A total of 25 articles on PubMed were retained for the study. All studies included pediatric patients (age up to 21 years) having benefited from an assessment of CYP2C19. CYP2C19 poor and intermediate metabolizers exhibit a higher trough plasma concentration of voriconazole, and PPIs compared to the rapid and ultra-rapid metabolizers. The pharmacogenetic data relative to CYP2C19 and clopidogrel in the pediatric population are not yet available. CYP2C19 poor metabolizers have a higher trough plasma concentration of antidepressants compared to the rapid and the ultra-rapid metabolizers. Modification of allele-specific PCR through the introduction of artificial mismatch is presented. CYP2C19 genotyping remains a powerful tool needed to optimize the treatment of children receiving voriconazole, PPIs, and anti-depressants.
PubMed: 36143168
DOI: 10.3390/jpm12091383 -
Chemico-biological Interactions Nov 2016In plants, sulfur is an essential nutrient that must be converted into usable metabolic forms for the formation of sulfur-containing amino acids and peptides (primary... (Review)
Review
In plants, sulfur is an essential nutrient that must be converted into usable metabolic forms for the formation of sulfur-containing amino acids and peptides (primary route) and for the modification of diverse metabolites (secondary route). In plants, the fate of assimilated sulfate depends on the three enzymes - ATP sulfurylase, adenosine-5'-phosphate (APS) reductase, and APS kinase - that form a branchpoint in the pathway. ATP sulfurylase catalyzes the formation of the critical intermediate APS, which can either be used in the primary assimilatory route or be phosphorylated to 3'-phospho-APS (PAPS) for a variety of sulfation reactions. Recent biochemical and structural studies of the branchpoint enzymes in plant sulfur metabolism suggest that redox-regulation may control sulfur partitioning between primary and secondary routes. Disulfide-based redox switches differentially affect APS reductase and APS kinase. Oxidative conditions that promote disulfide formation increase the activity of APS reductase and decreases PAPS production by APS kinase. Here we review recent work on the ATP sulfurylase and APS kinase from plants that provide new insight on the regulation of PAPS formation, the structural evolution of these enzymes in different organisms, and redox-control of this key branchpoint in plant sulfur metabolism.
Topics: Metabolic Networks and Pathways; Oxidation-Reduction; Plant Proteins; Plants; Sulfates
PubMed: 26926807
DOI: 10.1016/j.cbi.2016.02.017 -
Sports Medicine (Auckland, N.Z.) Mar 2017Substantial amounts of fructose are present in our diet. Unlike glucose, this hexose cannot be metabolized by most cells and has first to be converted into glucose,... (Review)
Review
Substantial amounts of fructose are present in our diet. Unlike glucose, this hexose cannot be metabolized by most cells and has first to be converted into glucose, lactate or fatty acids by enterocytes, hepatocytes and kidney proximal tubule cells, which all express specific fructose-metabolizing enzymes. This particular metabolism may then be detrimental in resting, sedentary subjects; however, this may also present some advantages for athletes. First, since fructose and glucose are absorbed through distinct, saturable gut transporters, co-ingestion of glucose and fructose may increase total carbohydrate absorption and oxidation. Second, fructose is largely metabolized into glucose and lactate, resulting in a net local lactate release from splanchnic organs (mostly the liver). This 'reverse Cori cycle' may be advantageous by providing lactate as an additional energy substrate to the working muscle. Following exercise, co-ingestion of glucose and fructose mutually enhance their own absorption and storage.
Topics: Athletes; Athletic Performance; Carbohydrate Metabolism; Dietary Carbohydrates; Exercise; Fructose; Glucose; Humans; Sports Nutritional Physiological Phenomena
PubMed: 28332117
DOI: 10.1007/s40279-017-0692-4 -
Critical Reviews in Biotechnology Nov 2020Metabolic engineering is crucial in the development of production strains for platform chemicals, pharmaceuticals and biomaterials from renewable resources. The central... (Review)
Review
Metabolic engineering is crucial in the development of production strains for platform chemicals, pharmaceuticals and biomaterials from renewable resources. The central carbon metabolism (CCM) of heterotrophs plays an essential role in the conversion of biomass to the cellular building blocks required for growth. Yet, engineering the CCM ultimately aims toward a maximization of flux toward products of interest. The most abundant dissimilative carbohydrate pathways amongst prokaryotes (and eukaryotes) are the Embden-Meyerhof-Parnas (EMP) and the Entner-Doudoroff (ED) pathways, which build the basics for heterotrophic metabolic chassis strains. Although the EMP is regarded as the textbook example of a carbohydrate pathway owing to its central role in production strains like , and , it is either modified, complemented or even replaced by alternative carbohydrate pathways in different organisms. The ED pathway also plays key roles in biotechnological relevant bacteria, like and , and its importance was recently discovered in photoautotrophs and marine microorganisms. In contrast to the EMP, the ED pathway and its variations are not evolutionary optimized for high ATP production and it differs in key principles such as protein cost, energetics and thermodynamics, which can be exploited in the construction of unique metabolic designs. Single ED pathway enzymes and complete ED pathway modules have been used to rewire carbon metabolisms in production strains and for the construction of cell-free enzymatic pathways. This review focuses on the differences of the ED and EMP pathways including their variations and discusses the use of alternative pathway strategies for and cell-free metabolic engineering.
Topics: Bacteria; Carbohydrate Metabolism; Cell-Free System; Metabolic Engineering; Metabolic Networks and Pathways; Thermodynamics
PubMed: 32654530
DOI: 10.1080/07388551.2020.1785386