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Digestive Diseases and Sciences Mar 2023The thiopurine medications are well established in the treatment of inflammatory bowel disease (IBD). There is significant variation in levels of toxic and therapeutic... (Observational Study)
Observational Study
BACKGROUND
The thiopurine medications are well established in the treatment of inflammatory bowel disease (IBD). There is significant variation in levels of toxic and therapeutic metabolites. Current data from small or short-term studies support therapeutic drug monitoring (TDM) in assessing azathioprine (AZA) and 6-mercaptopurine (6MP). TDM of thiopurines involves measurement and interpretation of metabolites 6-TGN and 6-MMPR.
AIMS
This study aimed to assess long-cterm outcomes of patients on thiopurines following therapeutic drug monitoring.
METHODS
A multicenter retrospective observational study of outcomes post thiopurine TDM was conducted. Demographics, disease characteristics, physician global assessment, IBD therapy at baseline TDM and again at 12 months were collected. Clinical outcomes were analyzed according to TDM result, and indication for TDM including proactive and other indications.
RESULTS
The study included 541 patients. Only 39% of patients had appropriate dosing of thiopurines. AZA/6MP TDM informed a management change in 61.9%, and enabled 88.8% of the cohort to continue AZA/6MP following TDM. At 12 months following TDM the majority (74.1%) of the cohort remained on AZA/6MP. Clinical remission was higher at 12-months following thiopurines TDM (68%) compared to baseline (37%), including proactive TDM. Post TDM, 13.0% of patients were identified as shunters and commenced on thiopurine-allopurinol co-therapy.
CONCLUSION
Thiopurine TDM resulted in a change in management for the majority of patients. Post TDM significantly more patients were in remission. TDM allowed the identification of non-adherence and shunters who, without intervention, would not reach therapeutic drug levels. Proactive TDM allowed identification and management of inappropriate dosing, and was associated with increased levels of clinical remission.
Topics: Humans; Azathioprine; Mercaptopurine; Inflammatory Bowel Diseases; Retrospective Studies; Methylthioinosine; Immunosuppressive Agents
PubMed: 35687221
DOI: 10.1007/s10620-022-07556-y -
Reproductive Toxicology (Elmsford, N.Y.) Aug 2022Thiopurine prodrugs (azathioprine, AZA, and 6-mercaptopurine, 6MP) are embryotoxic to rodents and rabbits. Little is known about the developmental toxicity of...
Thiopurine prodrugs (azathioprine, AZA, and 6-mercaptopurine, 6MP) are embryotoxic to rodents and rabbits. Little is known about the developmental toxicity of 6-methylmercaptopurine riboside (6MMPr), a thiopurine drug metabolite that is thought to mediate its liver toxicity. A limb bud assay found that 6MMPr impairs the in vitro morphogenetic differentiation of mouse limb extremities, being more potent than 6MP in the assay. This study evaluated the embryotoxicity of 6MMPr (0, 7.5, 15, 30 mg/kg bw sc) in rats after single-dose exposure in mid organogenesis (GD10). One group of pregnant rats was similarly treated with 6MP (15 mg/kg bw sc). After C-section (GD21), fetuses were weighed, and examined for external abnormalities. One third of each litter was examined for soft-tissue abnormalities while the remaining fetuses were cleared and stained for skeleton evaluation. 6MMPr caused a dose-dependent maternal weight loss followed by recovery before term pregnancy. Except for a nonsignificant increase in embryolethality and slight reduction in fetal weight at 30 mg/kg bw, no indication of embryotoxicity was noted at this dose or at lower doses of 6MMPr. In contrast, 6MP led to nearly 98 % of post-implantation losses in the presence of slight-to-mild maternal toxicity. These results are consistent with the notion that maternal treatment with 6MMPr affects embryo development, causing a nonsignificant increase in embryolethality and a slight reduction in fetal weight at 30 mg/kg bw. However, there was no increase in abnormalities at this dose, which was severely toxic to the dams, as reflected in the maternal weight gain data.
Topics: Abnormalities, Drug-Induced; Animals; Body Weight; Dose-Response Relationship, Drug; Embryo Implantation; Embryonic Development; Female; Fetal Weight; Methylthioinosine; Mice; Pregnancy; Rabbits; Rats
PubMed: 35662571
DOI: 10.1016/j.reprotox.2022.05.015 -
Journal of Pharmaceutical and... Aug 2022Mercaptopurine (6-MP) is an indispensable, first-line, drug in the treatment of pediatric acute lymphoblastic leukemia (ALL). However, 6-MP has several intrinsic...
Mercaptopurine (6-MP) is an indispensable, first-line, drug in the treatment of pediatric acute lymphoblastic leukemia (ALL). However, 6-MP has several intrinsic drawbacks, such as large individual variability in the drug response, undesirable adverse reactions, and drug resistance in patients with release ALL, which requires therapeutic drug monitoring (TDM). Several studies analyzed the total concentration of thiopurine nucleotides in red blood cells (RBCs) after hydrolysis, and two studies detected them separately and accurately by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, we developed a rapid and robust LC-MS/MS method for simultaneous quantitation of mono-, di-, and triphosphates of thioguanosine and methylthioinosine. Not only EDTA and DTT were added, but also EHT1864, a new Rac family small GTPases inhibitor, was innovatively added to ensure the stability of the analytes. Commercial availability and relatively low cost compound methotrexate-D3 was selected as internal standards. The linearity, accuracy, precision, recovery, matrix effect and stability of the method were all in line with the guidelines. This method provide an accurate and robust new solution for the determination of 6 metabolites of MP in RBCs from ALL patients with maintenance therapy.
Topics: Child; Chromatography, Liquid; Humans; Mercaptopurine; Methylthioinosine; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Tandem Mass Spectrometry
PubMed: 35550492
DOI: 10.1016/j.jpba.2022.114813 -
Cell Reports Apr 2022The innate immune recognition of the malaria-causing pathogen Plasmodium falciparum (P. falciparum) is not fully explored. Here, we identify the nucleoside...
The innate immune recognition of the malaria-causing pathogen Plasmodium falciparum (P. falciparum) is not fully explored. Here, we identify the nucleoside 5'-methylthioinosine (MTI), a Plasmodium-specific intermediate of the purine salvage pathway, as a pathogen-derived Toll-like receptor 8 (TLR8) agonist. Co-incubation of MTI with the TLR8 enhancer poly(dT) as well as synthetic or P. falciparum-derived RNA strongly increase its stimulatory activity. Of note, MTI generated from methylthioadenosine (MTA) by P. falciparum lysates activates TLR8 when MTI metabolism is inhibited by immucillin targeting the purine nucleoside phosphorylase (PfPNP). Importantly, P. falciparum-infected red blood cells incubated with MTI or cultivated with MTA and immucillin lead to TLR8-dependent interleukin-6 (IL-6) production in human monocytes. Our data demonstrate that the nucleoside MTI is a natural human TLR8 ligand with possible in vivo relevance for innate sensing of P. falciparum.
Topics: Humans; Malaria, Falciparum; Methylthioinosine; Nucleosides; Plasmodium falciparum; Purine-Nucleoside Phosphorylase; Purines; Toll-Like Receptor 8
PubMed: 35417716
DOI: 10.1016/j.celrep.2022.110691 -
Chemistry & Biodiversity Apr 2022In our continuous screening for bioactive microbial natural products, the culture extracts of a terrestrial Actinomycetes sp. GSCW-51 yielded two new metabolites,...
In our continuous screening for bioactive microbial natural products, the culture extracts of a terrestrial Actinomycetes sp. GSCW-51 yielded two new metabolites, i. e., 5-hydroxymethyl-3-(1-hydroxy-6-methyl-7-oxooctyl)dihydrofuran-2(3H)-one (1), 5-hydroxymethyl-3-(1,7-dihydroxy-6-methyloctyl)dihydrofuran-2(3H)-one (2), and two known compounds; 5'-methylthioinosine (3), and 5'-methylthioinosine sulfoxide (4), which are isolated first time from any natural source, along with four known compounds (5-8). The structures of the new compounds were deduced by HR-ESI-MS, 1D and 2D NMR data, and in comparison with related compounds from the literature. Additionally, owing to the current COVID-19 pandemic situation, we also computationally explored the therapeutic potential of our isolated compounds against SARS-CoV-2. Compound 4 showed the best binding energies of -6.2 and -6.6 kcal/mol for M and spike proteins, respectively. The intermolecular interactions were also studied using 2-D and 3-D imagery, which also supported the binding energies as well as put several insights under the spotlight. Furthermore, Lipinski's rule of 5 was used to predict the drug likeness of compounds 1-4, which indicated all compounds obey Lipinski's rule of 5. The study of bioavailability radars of the compounds 1-4 also confirmed their drug likeness properties where all the five crucial drug likeness parameters are in color area, which is safe to be used as drugs. Our isolation and computational findings highly encourage the scientific community to do further in vitro and in vivo studies of compounds 1-4.
Topics: Actinomyces; Humans; Molecular Docking Simulation; Molecular Dynamics Simulation; Pandemics; SARS-CoV-2; Thioinosine; COVID-19 Drug Treatment
PubMed: 35213767
DOI: 10.1002/cbdv.202100843 -
Viruses Dec 2021Broad-spectrum antiviral therapies hold promise as a first-line defense against emerging viruses by blunting illness severity and spread until vaccines and...
Broad-spectrum antiviral therapies hold promise as a first-line defense against emerging viruses by blunting illness severity and spread until vaccines and virus-specific antivirals are developed. The nucleobase favipiravir, often discussed as a broad-spectrum inhibitor, was not effective in recent clinical trials involving patients infected with Ebola virus or SARS-CoV-2. A drawback of favipiravir use is its rapid clearance before conversion to its active nucleoside-5'-triphosphate form. In this work, we report a synergistic reduction of flavivirus (dengue, Zika), orthomyxovirus (influenza A), and coronavirus (HCoV-OC43 and SARS-CoV-2) replication when the nucleobases favipiravir or T-1105 were combined with the antimetabolite 6-methylmercaptopurine riboside (6MMPr). The 6MMPr/T-1105 combination increased the C-U and G-A mutation frequency compared to treatment with T-1105 or 6MMPr alone. A further analysis revealed that the 6MMPr/T-1105 co-treatment reduced cellular purine nucleotide triphosphate synthesis and increased conversion of the antiviral nucleobase to its nucleoside-5'-monophosphate, -diphosphate, and -triphosphate forms. The 6MMPr co-treatment specifically increased production of the active antiviral form of the nucleobases (but not corresponding nucleosides) while also reducing levels of competing cellular NTPs to produce the synergistic effect. This in-depth work establishes a foundation for development of small molecules as possible co-treatments with nucleobases like favipiravir in response to emerging RNA virus infections.
Topics: Adenosine Triphosphate; Amides; Animals; Antimetabolites; Antiviral Agents; Cell Line; Drug Synergism; Guanosine Triphosphate; Humans; Methylthioinosine; Mutation; Phosphoribosyl Pyrophosphate; Pyrazines; RNA Viruses; RNA, Viral; Virus Replication
PubMed: 34960780
DOI: 10.3390/v13122508 -
Bioscience, Biotechnology, and... Dec 20212-Methylthio-N7-methyl-cis-zeatin (1) was isolated from the culture broth of Streptomyces sp. 80H647 along with 2 known purine derivatives, 5'-methylthioinosine (2) and...
2-Methylthio-N7-methyl-cis-zeatin (1) was isolated from the culture broth of Streptomyces sp. 80H647 along with 2 known purine derivatives, 5'-methylthioinosine (2) and AT-265 (dealanylascamycin, 3). The structure elucidation of compound 1 was accomplished by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) analyses. It inhibited the growth of Plasmodium falciparum 3D7 with a GI50 of 2.4 µm and had no effect on the growth of Arabidopsis at 2 µm. This is the first report of an N7-methylated zeatin-type natural product from Streptomyces and as an antimalarial compound.
Topics: Antimalarials
PubMed: 34734225
DOI: 10.1093/bbb/zbab192 -
Journal of Chromatography. B,... Jan 2020Individualized therapy involves genetic test of drug metabolism, which provides information about the initial dose and therapeutic drug monitoring for adjusting the...
Individualized therapy involves genetic test of drug metabolism, which provides information about the initial dose and therapeutic drug monitoring for adjusting the subsequent dose. Consequently, toxic side effects are expected to be minimized and therapeutic effects to be maximized. In this study, an ultra-performance liquid chromatography tandem mass spectrometry method that was specific, accurate and sensitive was developed to simultaneously determine azathioprine two metabolites, 6-thioguanine nucleotides (6-TGN) and 6-methyl-mercaptopurine riboside (6-MMPr) in the whole blood lysate. We precipitated the sample by trifluoroacetic acid under the protection of dithiothreitol, with 6-MMPr and 6-TGN being hydrolyzed to produce 6-methymercaptopurine and 6-thioguanine. In the chromatographic separation, Waters ACQUITY BEH C18 (2.1 × 100 mm, 1.7 μm) chromatographic column was applied and gradient elution was conducted with 0.02 mol/L ammonium acetate buffer (which contains 0.3% formic acid) and acetonitrile at a flow rate of 0.4 ml/min. Tandem mass spectrometry in multiple reaction monitoring mode was applied for detection via electrospray ionization source in positive ionization mode. The analyzing process lasted for no more than 2 min. The calibration curve for each metabolite fitted a least squares model (weighed 1/X) from 1.25 to 5000 ng/ml (r > 0.99). The ion pairs were detected as 6-MMP m/z 167.07 → 152.15, 6-TG m/z 168.06 → 134.13, and internal standard m/z 171.07 → 137.14. Under the guidance of FDA guidelines for bioanalytical method validation, we carried out validation and obtained satisfactory results. The method was successfully utilized for monitoring the concentrations of each metabolite from 65 affected patients who had received azathioprine maintenance therapy and achieved optimal results.
Topics: Adult; Azathioprine; Chromatography, High Pressure Liquid; Drug Monitoring; Female; Guanine Nucleotides; Humans; Limit of Detection; Linear Models; Male; Methylthioinosine; Middle Aged; Reproducibility of Results; Tandem Mass Spectrometry; Thionucleotides
PubMed: 31809961
DOI: 10.1016/j.jchromb.2019.121802 -
Archives of Biochemistry and Biophysics May 2019Plasmodium falciparum (Pf), a malarial pathogen, can only synthesize purine nucleotides employing a salvage pathway because it lacks de novo biosynthesis. Adenosine...
Plasmodium falciparum (Pf), a malarial pathogen, can only synthesize purine nucleotides employing a salvage pathway because it lacks de novo biosynthesis. Adenosine deaminase (ADA), one of the three purine salvage enzymes, catalyzes the irreversible hydrolytic deamination of adenosine to inosine, which is further converted to GMP and AMP for DNA/RNA production. In addition to adenosine conversion, Plasmodium ADA also catalyzes the conversion of 5'-methylthioadenosine, derived from polyamine biosynthesis, into 5'-methylthioinosine whereas the human enzyme is not capable of this function. Here we report the crystal structure of a surface engineered PfADA at a resolution of 2.48 Å, together with results on kinetic studies of PfADA wild-type and active site variants. The structure reveals a novel inosine binding pocket linked to a distinctive PfADA substructure (residues 172-179) derived from a non-conserved gating helix loop (172-188) in Plasmodium spp. and other ADA enzymes. Variants of PfADA and human (h) ADA active site amino acids were generated in order to study their role in catalysis, including PfADA- Phe136, -Thr174, -Asp176, and -Leu179, and hADA-Met155, equivalent to PfADA-Asp176. PfADA-Leu179His showed no effect on kinetic parameters. However, kinetic results of PfADA-Asp176Met/Ala mutants and hADA-Met155Asp/Ala showed that the mutation reduced adenosine and 5'-methylthioadenosine substrate affinity in PfADA and k in hADA, thereby reducing catalytic efficiency of the enzyme. Phe136Leu mutant showed increased K (>10-fold) for both substrates whereas Thr174Ile/Ala only affected 5'-methylthioadenosine binding affinity. Together, the structure with the novel inosine binding pocket and the kinetic data provide insights for rational design of inhibitors against PfADA.
Topics: Adenosine Deaminase; Adenosine Deaminase Inhibitors; Amino Acid Sequence; Amino Acid Substitution; Catalytic Domain; Crystallography, X-Ray; Drug Design; Humans; Inosine; Kinetics; Models, Molecular; Mutagenesis, Site-Directed; Plasmodium falciparum; Protozoan Proteins; Recombinant Proteins; Sequence Homology, Amino Acid; Substrate Specificity
PubMed: 31002765
DOI: 10.1016/j.abb.2019.04.002 -
International Journal of Antimicrobial... Oct 2018
Topics: Antiviral Agents; Cell Line; Methylthioinosine
PubMed: 30318058
DOI: 10.1016/j.ijantimicag.2018.06.021