tetrahydrouridine has been researched along with Disease-Models--Animal* in 5 studies
1 trial(s) available for tetrahydrouridine and Disease-Models--Animal
4 other study(ies) available for tetrahydrouridine and Disease-Models--Animal
Article | Year |
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Deoxycytidine and Deoxythymidine Treatment for Thymidine Kinase 2 Deficiency.
Thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial pyrimidine salvage pathway, is essential for mitochondrial DNA (mtDNA) maintenance. Mutations in the nuclear gene, TK2, cause TK2 deficiency, which manifests predominantly in children as myopathy with mtDNA depletion. Molecular bypass therapy with the TK2 products, deoxycytidine monophosphate (dCMP) and deoxythymidine monophosphate (dTMP), prolongs the life span of Tk2-deficient (Tk2. To test these hypotheses, we assessed two therapies in Tk2. We observed that dC+dT delayed disease onset, prolonged life span of Tk2-deficient mice and restored mtDNA copy number as well as respiratory chain enzyme activities and levels. In contrast, dCMP+dTMP+THU therapy decreased life span of Tk2. Our studies demonstrate that deoxynucleoside substrate enhancement is a novel therapy, which may ameliorate TK2 deficiency in patients. Ann Neurol 2017;81:641-652. Topics: Animals; Antimetabolites; Deoxycytidine Monophosphate; Disease Models, Animal; DNA, Mitochondrial; Drug Therapy, Combination; Metabolism, Inborn Errors; Mice; Mice, Transgenic; Mitochondrial Diseases; Tetrahydrouridine; Thymidine; Thymidine Kinase | 2017 |
Preclinical studies of 5-fluoro-2'-deoxycytidine and tetrahydrouridine in pediatric brain tumors.
Chemotherapies active in preclinical studies frequently fail in the clinic due to lack of efficacy, which limits progress for rare cancers since only small numbers of patients are available for clinical trials. Thus, a preclinical drug development pipeline was developed to prioritize potentially active regimens for pediatric brain tumors spanning from in vitro drug screening, through intracranial and intra-tumoral pharmacokinetics to in vivo efficacy studies. Here, as an example of the pipeline, data are presented for the combination of 5-fluoro-2'-deoxycytidine and tetrahydrouridine in three pediatric brain tumor models. The in vitro activity of nine novel therapies was tested against tumor spheres derived from faithful mouse models of Group 3 medulloblastoma, ependymoma, and choroid plexus carcinoma. Agents with the greatest in vitro potency were then subjected to a comprehensive series of in vivo pharmacokinetic (PK) and pharmacodynamic (PD) studies culminating in preclinical efficacy trials in mice harboring brain tumors. The nucleoside analog 5-fluoro-2'-deoxycytidine (FdCyd) markedly reduced the proliferation in vitro of all three brain tumor cell types at nanomolar concentrations. Detailed intracranial PK studies confirmed that systemically administered FdCyd exceeded concentrations in brain tumors necessary to inhibit tumor cell proliferation, but no tumor displayed a significant in vivo therapeutic response. Despite promising in vitro activity and in vivo PK properties, FdCyd is unlikely to be an effective treatment of pediatric brain tumors, and therefore was deprioritized for the clinic. Our comprehensive and integrated preclinical drug development pipeline should reduce the attrition of drugs in clinical trials. Topics: Animals; Antineoplastic Agents; Apoptosis; Brain; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Deoxycytidine; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Epigenesis, Genetic; Mice; Mice, Nude; Tetrahydrouridine | 2016 |
Feline leukemia virus-induced immunodeficiency syndrome in cats as a model for evaluation of antiretroviral therapy.
Severe progressive immunodeficiency syndrome can be induced experimentally with a molecularly cloned isolate of feline leukemia virus (FeLV-FAIDS). The resultant disease syndrome is characterized by persistent viremia, lymphopenia, progressive weight loss, persistent diarrhea, enteropathy, and opportunistic infections. The onset of clinical immunodeficiency disease is prefigured by the replication of the FeLV-FAIDS variant virus in bone marrow and other tissues. The FeLV-FAIDS system can be used to evaluate antiviral agents which act on steps in the replication cycle which are conserved among retroviruses (e.g. reverse transcriptase, protease, assembly). The persistence and magnitude of viremia serves as a useful parameter in antiviral studies because it can be easily measured, presages the eventual development of immunodeficiency, and provides a convenient indicator of therapeutic efficacy either in preventing de novo FeLV infection or in reversing or ameliorating established infection. We describe here the evaluation of 2',3'-dideoxycytidine (ddC) against FeLV-FAIDS infection - both in vitro in cell culture assay systems and in vivo in cats administered ddC either via intravenous bolus dosage or via controlled release subcutaneous implants. We found that, although controlled release delivery of ddC inhibited de novo FeLV-FAIDS replication and delayed onset of viremia when therapy was discontinued (after 3 weeks), an equivalent incidence and level of viremia were established rapidly in both ddC-treated and control cats. The FeLV model, therefore, can be used to assess rapidly experimental single agent or combined antiviral therapies for persistent retrovirus infection and disease. Topics: Acquired Immunodeficiency Syndrome; Animals; Cats; Cell Line; Cytopathogenic Effect, Viral; Delayed-Action Preparations; Dideoxynucleosides; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Implants; Drug Therapy, Combination; Immunologic Deficiency Syndromes; Injections, Intravenous; Injections, Subcutaneous; Leukemia Virus, Feline; Leukemia, Experimental; Retroviridae Infections; Specific Pathogen-Free Organisms; Tetrahydrouridine; Viremia; Zalcitabine | 1989 |
Treatment of FeLV-induced immunodeficiency syndrome (FeLV-FAIDS) with controlled release capsular implantation of 2',3'-dideoxycytidine.
2',3'-dideoxycytidine (ddC) inhibits replication of the immunodeficiency inducing strain of feline leukemia virus (FeLV-FAIDS) in vitro at concentrations ranging from 1-10 micrograms/ml. Additive antiviral effect is achieved when ddC is combined with either human recombinant alpha interferon (IFN alpha) or tumor necrosis factor (TNF) plus IFN alpha. Initial in vivo pharmacokinetic studies in cats, utilizing bolus intravenous administration of ddC (20 mg/kg), resulted in peak plasma concentrations of 15 micrograms/ml 1 min after administration and a half-life of approximately 1 h. These values could not be augmented with high levels of the deaminase blocker tetrahydrouridine administered prior to or concurrently with ddC. In vivo trials utilizing multiple, daily intravenous injections of ddC could not prevent the development of persistent viremia in cats infected with FeLV-FAIDS. To enhance ddC pharmacokinetics and antiviral activity, controlled release capsular implants were developed by blending ddC with a copolymer consisting of DL-lactide glycolide and hydroxypropyl cellulose, which was melt-spun into fibers and encapsulated in a sheath of polyethylene glycol for subcutaneous implantation. Pharmacokinetic studies, conducted in cats receiving an average dose of 600 mg of ddC, indicated an average peak plasma concentration of 17 micrograms/ml achieved at 6 h post implantation with 3.5 micrograms/ml noted at 48 h; and an extension of plasma half-life from 1.5 (bolus subcutaneous injection) to 20 h. sustained plasma concentrations of 1.5 to 10 micrograms/ml, equivalent to ddC levels previously shown to have anti-FeLV activity in vitro, were maintained throughout a 72 h period. Implantation devices could be replenished every 48 h and elevated plasma levels were sustained for four weeks without signs of clinical toxicity, sepsis or significant alterations in the hemogram. Initial clinical trials employing controlled release capsular ddC implants in vivo indicate significant retardation of FeLV-FAIDS replication throughout a four week treatment period. Topics: Acquired Immunodeficiency Syndrome; Animals; Antibodies, Monoclonal; Capsules; Cats; Dideoxynucleosides; Disease Models, Animal; Drug Implants; Drug Therapy, Combination; Gene Products, gag; Immunologic Deficiency Syndromes; Infusions, Intravenous; Injections, Subcutaneous; Interferon Type I; Leukemia Virus, Feline; Retroviridae Proteins; Tetrahydrouridine; Tumor Necrosis Factor-alpha; Virus Replication; Zalcitabine | 1989 |