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Current Opinion in Gastroenterology May 2015It is our opinion that there is an unmet need in hepatology for a minimally or noninvasive test of liver function and physiology. Quantitative liver function tests... (Review)
Review
PURPOSE OF REVIEW
It is our opinion that there is an unmet need in hepatology for a minimally or noninvasive test of liver function and physiology. Quantitative liver function tests define the severity and prognosis of liver disease by measuring the clearance of substrates whose uptake or metabolism is dependent upon liver perfusion or hepatocyte function. Substrates with high-affinity hepatic transporters exhibit high 'first-pass' hepatic extraction and their clearance measures hepatic perfusion. In contrast, substrates metabolized by the liver have low first-pass extraction and their clearance measures specific drug metabolizing pathways.
RECENT FINDINGS
We highlight one quantitative liver function test, the dual cholate test, and introduce the concept of a disease severity index linked to clinical outcome that quantifies the simultaneous processes of hepatocyte uptake, clearance from the systemic circulation, clearance from the portal circulation, and portal-systemic shunting.
SUMMARY
It is our opinion that dual cholate is a relevant test for defining disease severity, monitoring the natural course of disease progression, and quantifying the response to therapy.
Topics: Cholates; Health Services Needs and Demand; Hepatocytes; Humans; Liver; Liver Diseases; Liver Function Tests; Metabolic Clearance Rate; Predictive Value of Tests; Severity of Illness Index
PubMed: 25714706
DOI: 10.1097/MOG.0000000000000167 -
Biomolecules Aug 2021Pregnane X Receptor (PXR) belongs to the nuclear receptors' superfamily and mainly functions as a xenobiotic sensor activated by a variety of ligands. PXR is widely... (Review)
Review
Pregnane X Receptor (PXR) belongs to the nuclear receptors' superfamily and mainly functions as a xenobiotic sensor activated by a variety of ligands. PXR is widely expressed in normal and malignant tissues. Drug metabolizing enzymes and transporters are also under PXR's regulation. Antineoplastic agents are of particular interest since cancer patients are characterized by significant intra-variability to treatment response and severe toxicities. Various PXR polymorphisms may alter the function of the protein and are linked with significant effects on the pharmacokinetics of chemotherapeutic agents and clinical outcome variability. The purpose of this review is to summarize the roles of PXR polymorphisms in the metabolism and pharmacokinetics of chemotherapeutic drugs. It is also expected that this review will highlight the importance of PXR polymorphisms in selection of chemotherapy, prediction of adverse effects and personalized medicine.
Topics: Acetylation; Antineoplastic Agents; Biotransformation; Gene Expression; Humans; Inactivation, Metabolic; Neoplasms; Phosphorylation; Polymorphism, Single Nucleotide; Precision Medicine; Pregnane X Receptor; Protein Domains; Protein Processing, Post-Translational; Sumoylation; Treatment Outcome; Ubiquitination
PubMed: 34439808
DOI: 10.3390/biom11081142 -
Nutrients Nov 2021Diabetes remains one of the leading causes of deaths and co-morbidities in the world, with tremendous human, social and economic costs. Therefore, despite therapeutics... (Review)
Review
Diabetes remains one of the leading causes of deaths and co-morbidities in the world, with tremendous human, social and economic costs. Therefore, despite therapeutics and technological advancements, improved strategies to tackle diabetes management are still needed. One of the suggested strategies is the consumption of (poly)phenols. Positive outcomes of dietary (poly)phenols have been pointed out towards different features in diabetes. This is the case of ellagitannins, which are present in numerous foodstuffs such as pomegranate, berries, and nuts. Ellagitannins have been reported to have a multitude of effects on metabolic diseases. However, these compounds have high molecular weight and do not reach circulation at effective concentrations, being metabolized in smaller compounds. After being metabolized into ellagic acid in the small intestine, the colonic microbiota hydrolyzes and metabolizes ellagic acid into dibenzopyran-6-one derivatives, known as urolithins. These low molecular weight compounds reach circulation in considerable concentrations ranging until micromolar levels, capable of reaching target tissues. Different urolithins are formed throughout the metabolization process, but urolithin A, isourolithin A, and urolithin B, and their phase-II metabolites are the most frequent ones. In recent years, urolithins have been the focus of attention in regard to their effects on a multiplicity of chronic diseases, including cancer and diabetes. In this review, we will discuss the latest advances about the protective effects of urolithins on diabetes.
Topics: Biological Availability; Coumarins; Diabetes Mellitus; Fruit; Humans; Hydrolyzable Tannins; Nuts; Pomegranate; Protective Agents
PubMed: 34959837
DOI: 10.3390/nu13124285 -
Journal of Personalized Medicine Jul 2023Due to the chronic relapsing nature of mental disorders and increased life expectancy, the societal burden of these non-communicable diseases will increase even further.... (Review)
Review
Due to the chronic relapsing nature of mental disorders and increased life expectancy, the societal burden of these non-communicable diseases will increase even further. Treatments for mental disorders, such as depression, are available, but their effect is limited due to patients' (genetic) heterogeneity, low treatment compliance and frequent side effects. In general, only one-third of the patients respond to treatment. Today, medication selection in psychiatry relies on a trial-and-error approach based mainly on physicians' experience. Pharmacogenetic (PGx) testing can help in this process by determining the person-specific genetic factors that may predict clinical response and side effects associated with genetic variants that impact drug-metabolizing enzymes, drug transporters or drug targets. PGxis a discipline that investigates genetic factors that affect the absorption, metabolism, and transport of drugs, thereby affecting therapy outcome. These genetic factors can, among other things, lead to differences in the activity of enzymes that metabolize drugs. Studies in depressed patients show that genotyping of drug-metabolizing enzymes can increase the effectiveness of treatment, which could benefit millions of patients worldwide. This review highlights these studies, gives recommendations and provides future perspectives on how to proceed with PGx testing. Finally, it is recommended to consider genotyping for and , when there is an indication (side effects or inefficacy).
PubMed: 37511796
DOI: 10.3390/jpm13071183 -
Frontiers in Immunology 2024Excess dietary fructose consumption has been long proposed as a culprit for the world-wide increase of incidence in metabolic disorders and cancer within the past... (Review)
Review
Excess dietary fructose consumption has been long proposed as a culprit for the world-wide increase of incidence in metabolic disorders and cancer within the past decades. Understanding that cancer cells can gradually accumulate metabolic mutations in the tumor microenvironment, where glucose is often depleted, this raises the possibility that fructose can be utilized by cancer cells as an alternative source of carbon. Indeed, recent research has increasingly identified various mechanisms that show how cancer cells can metabolize fructose to support their proliferating and migrating needs. In light of this growing interest, this review will summarize the recent advances in understanding how fructose can metabolically reprogram different types of cancer cells, as well as how these metabolic adaptations can positively support cancer cells development and malignancy.
Topics: Humans; Fructose; Neoplasms; Tumor Microenvironment; Animals; Cellular Reprogramming; Energy Metabolism; Metabolic Reprogramming
PubMed: 38711514
DOI: 10.3389/fimmu.2024.1375461 -
International Journal of Molecular... Oct 2020In vitro methods which incorporate metabolic capability into the assays allow us to assess the activity of metabolites from their parent compounds. These methods can be... (Review)
Review
In vitro methods which incorporate metabolic capability into the assays allow us to assess the activity of metabolites from their parent compounds. These methods can be applied into high-throughput screening (HTS) platforms, thereby increasing the speed to identify compounds that become active via the metabolism process. HTS was originally used in the pharmaceutical industry and now is also used in academic settings to evaluate biological activity and/or toxicity of chemicals. Although most chemicals are metabolized in our body, many HTS assays lack the capability to determine compound activity via metabolism. To overcome this problem, several in vitro metabolic methods have been applied to an HTS format. In this review, we describe in vitro metabolism methods and their application in HTS assays, as well as discuss the future perspectives of HTS with metabolic activity. Each in vitro metabolism method has advantages and disadvantages. For instance, the S9 mix has a full set of liver metabolic enzymes, but it displays high cytotoxicity in cell-based assays. In vitro metabolism requires liver fractions or the use of other metabolically capable systems, including primary hepatocytes or recombinant enzymes. Several newly developed in vitro metabolic methods, including HepaRG cells, three-dimensional (3D) cell models, and organ-on-a-chip technology, will also be discussed. These newly developed in vitro metabolism approaches offer significant progress in dissecting biological processes, developing drugs, and making toxicology studies quicker and more efficient.
Topics: Cells, Cultured; Drug Evaluation, Preclinical; Hepatocytes; High-Throughput Screening Assays; Humans; Inactivation, Metabolic
PubMed: 33142951
DOI: 10.3390/ijms21218182 -
Biochimica Et Biophysica Acta Feb 2013Although at low concentrations, arsenic commonly occurs naturally as a local geological constituent. Whereas both arsenate and arsenite are strongly toxic to life, a... (Review)
Review
Although at low concentrations, arsenic commonly occurs naturally as a local geological constituent. Whereas both arsenate and arsenite are strongly toxic to life, a number of prokaryotes use these compounds as electron acceptors or donors, respectively, for bioenergetic purposes via respiratory arsenate reductase, arsenite oxidase and alternative arsenite oxidase. The recent burst in discovered arsenite oxidizing and arsenate respiring microbes suggests the arsenic bioenergetic metabolisms to be anything but exotic. The first goal of the present review is to bring to light the widespread distribution and diversity of these metabolizing pathways. The second goal is to present an evolutionary analysis of these diverse energetic pathways. Taking into account not only the available data on the arsenic metabolizing enzymes and their phylogenetical relatives but also the palaeogeochemical records, we propose a crucial role of arsenite oxidation via arsenite oxidase in primordial life. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.
Topics: Alcaligenes faecalis; Arsenate Reductases; Arsenic; Energy Metabolism; Oxidation-Reduction; Oxidoreductases; Protein Conformation
PubMed: 22982475
DOI: 10.1016/j.bbabio.2012.08.007 -
PloS One 2016Humans are exposed to numerous xenobiotics, a majority of which are in the form of pharmaceuticals. Apart from human enzymes, recent studies have indicated the role of...
Humans are exposed to numerous xenobiotics, a majority of which are in the form of pharmaceuticals. Apart from human enzymes, recent studies have indicated the role of the gut bacterial community (microbiome) in metabolizing xenobiotics. However, little is known about the contribution of the plethora of gut microbiome in xenobiotic metabolism. The present study reports the results of analyses on xenobiotic metabolizing enzymes in various human gut microbiomes. A total of 397 available gut metagenomes from individuals of varying age groups from 8 nationalities were analyzed. Based on the diversities and abundances of the xenobiotic metabolizing enzymes, various bacterial taxa were classified into three groups, namely, least versatile, intermediately versatile and highly versatile xenobiotic metabolizers. Most interestingly, specific relationships were observed between the overall drug consumption profile and the abundance and diversity of the xenobiotic metabolizing repertoire in various geographies. The obtained differential abundance patterns of xenobiotic metabolizing enzymes and bacterial genera harboring them, suggest their links to pharmacokinetic variations among individuals. Additional analyses of a few well studied classes of drug modifying enzymes (DMEs) also indicate geographic as well as age specific trends.
Topics: Adolescent; Adult; Age Factors; Aged; Bacteria; Child; Child, Preschool; Enzymes; Ethnicity; Female; Gastrointestinal Microbiome; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Humans; Inactivation, Metabolic; Infant; Infant, Newborn; Male; Metabolic Networks and Pathways; Metagenome; Middle Aged; Xenobiotics
PubMed: 27695034
DOI: 10.1371/journal.pone.0163099 -
BioMed Research International 2013Succinate is a promising chemical which has wide applications and can be produced by biological route. The history of the biosuccinate production shows that the joint... (Review)
Review
Succinate is a promising chemical which has wide applications and can be produced by biological route. The history of the biosuccinate production shows that the joint effort of different metabolic engineering approaches brings successful results. In order to enhance the succinate production, multiple metabolical strategies have been sought. In this review, different overproducers for succinate production, including natural succinate overproducers and metabolic engineered overproducers, are examined and the metabolic engineering strategies and performances are discussed. Modification of the mechanism of substrate transportation, knocking-out genes responsible for by-products accumulation, overexpression of the genes directly involved in the pathway, and improvement of internal NADH and ATP formation are some of the strategies applied. Combination of the appropriate genes from homologous and heterologous hosts, extension of substrate, integrated production of succinate, and other high-value-added products are expected to bring a desired objective of producing succinate from renewable resources economically and efficiently.
Topics: Biological Transport; Genetic Engineering; Metabolic Engineering; Metabolic Networks and Pathways; Succinic Acid
PubMed: 23691505
DOI: 10.1155/2013/538790 -
Cells Jul 2021Cancer stem cells (CSCs) are heterogeneous cells with stem cell-like properties that are responsible for therapeutic resistance, recurrence, and metastasis, and are the... (Review)
Review
Cancer stem cells (CSCs) are heterogeneous cells with stem cell-like properties that are responsible for therapeutic resistance, recurrence, and metastasis, and are the major cause for cancer treatment failure. Since CSCs have distinct metabolic characteristics that plays an important role in cancer development and progression, targeting metabolic pathways of CSCs appears to be a promising therapeutic approach for cancer treatment. Here we classify and discuss the unique metabolisms that CSCs rely on for energy production and survival, including mitochondrial respiration, glycolysis, glutaminolysis, and fatty acid metabolism. Because of metabolic plasticity, CSCs can switch between these metabolisms to acquire energy for tumor progression in different microenvironments compare to the rest of tumor bulk. Thus, we highlight the specific conditions and factors that promote or suppress CSCs properties to portray distinct metabolic phenotypes that attribute to CSCs in common cancers. Identification and characterization of the features in these metabolisms can offer new anticancer opportunities and improve the prognosis of cancer. However, the therapeutic window of metabolic inhibitors used alone or in combination may be rather narrow due to cytotoxicity to normal cells. In this review, we present current findings of potential targets in these four metabolic pathways for the development of more effective and alternative strategies to eradicate CSCs and treat cancer more effectively in the future.
Topics: Animals; Glutamine; Humans; Metabolic Networks and Pathways; Mitochondria; Molecular Targeted Therapy; Neoplastic Stem Cells; Oxidative Phosphorylation
PubMed: 34359941
DOI: 10.3390/cells10071772