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Walker UA, Lebrecht D, Reichard W, Kirschner J, Bissé E, Iversen L, Venhoff AC, Venhoff N. Zidovudine induces visceral mitochondrial toxicity and intra-abdominal fat gain in a rodent model of lipodystrophy. Antivir Ther 2014; 19:783-92. [PMID: 24584039 DOI: 10.3851/imp2758] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND The use of zidovudine is associated with a loss of subcutaneous adipose tissue (SAT). We assessed if zidovudine treatment also affects visceral adipose tissue (VAT) and if uridine supplementation abrogates the adverse effects of zidovudine on VAT. METHODS Rats were fed zidovudine for 21 weeks with or without simultaneous uridine supplementation. Control animals did not receive zidovudine, or were treated with uridine alone. Changes in SAT and VAT were monitored by magnetic resonance imaging. Adipose tissue was examined for structural and molecular signs of mitochondrial toxicity. RESULTS Zidovudine induced lipoatrophy in SAT and fat hypertrophy in VAT. Compared with controls zidovudine-exposed VAT adipocytes had increased diameters, microvesicular steatosis and enlarged mitochondria with disrupted crystal architecture on electron microscopy. VAT adipocyte mitochondrial DNA (mtDNA) copy numbers were diminished, as were mtDNA-encoded respiratory chain proteins. The 'common' mtDNA deletion was detected in high frequencies in zidovudine treated animals, but not in the controls. Although mtDNA depletion was more profound in SAT compared with VAT, the 'common' deletion tended to be more frequent in the VAT than in the SAT. Uridine coadministration abrogated all effects of zidovudine on VAT and SAT pathology. CONCLUSIONS Zidovudine induces a gain of intra-abdominal fat in association with quantitative and qualitative alterations of the mitochondrial genome and impaired expression of mtDNA-encoded respiratory chain components, indicating that zidovudine may contribute to abdominal fat hypertrophy in HIV-infected patients. In this rodent model, uridine supplementation abrogates both SAT and VAT pathology induced by zidovudine.
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Affiliation(s)
- Ulrich A Walker
- Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, Freiburg, Germany
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Role of pyrimidine depletion in the mitochondrial cardiotoxicity of nucleoside analogue reverse transcriptase inhibitors. J Acquir Immune Defic Syndr 2011; 55:550-7. [PMID: 20827217 DOI: 10.1097/qai.0b013e3181f25946] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Long-term antiretroviral treatment with nucleoside analogue reverse transcriptase inhibitors (NRTI) may result in a cardiomyopathy due to mitochondrial DNA (mtDNA) depletion. An intact mitochondrial function is required for the synthesis of intramyocardial pyrimidine nucleotides, which in turn are building blocks of mtDNA. We investigated if NRTI-related cardiomyopathy can be prevented with pyrimidine precursors. METHODS Mice were fed with zidovudine or zalcitabine with or without simultaneous Mitocnol, a dietary supplement with high uridine bioavailability. Myocardia were examined after 9 weeks. RESULTS Both NRTI induced a cardiomyopathy with mitochondrial enlargement, a disrupted cristal architecture on electron microscopy and diminished myocardial mtDNA copy numbers. The myocardial mtDNA-encoded cytochrome c-oxidase I subunit was impaired more profoundly than the nucleus-encoded cytochrome c-oxidase IV subunit. The myocardial formation of reactive oxygen species and mtDNA mutations was enhanced in zidovudine and zalcitabine treated animals. Mitocnol attenuated or normalized all myocardial pathology when given with both NRTI, but by itself had no intrinsic effects and no apparent adverse effects. CONCLUSIONS Zidovudine and zalcitabine induce a mitochondrial cardiomyopathy, which is antagonized with uridine supplementation, implicating pyrimidine pool depletion in its pathogenesis. Pyrimidine pool replenishment may be exploited clinically because uridine is well tolerated.
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McComsey GA, O'Riordan M, Choi J, Libutti D, Rowe D, Storer N, Harrill D, Gerschenson M. Mitochondrial function, inflammation, fat and bone in HIV lipoatrophy: randomized study of uridine supplementation or switch to tenofovir. Antivir Ther 2011; 17:347-53. [PMID: 22293126 DOI: 10.3851/imp1928] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2011] [Indexed: 10/16/2022]
Abstract
BACKGROUND Lipoatrophy modestly improves when the thymidine analogue nucleoside reverse transcriptase inhibitor (tNRTI) is removed. In vitro, uridine (NucleomaxX(®); Pharma Nord, Vojens, Denmark) reversed tNRTI mitochondrial toxicity. METHODS All patients had lipoatrophy on a tNRTI-containing regimen with HIV RNA<400 copies/ml. A randomized 48-week study switched patients from tNRTI to tenofovir (TDF) or added uridine (continuing tNRTI). End points were changes in limb fat (DEXA), subcutaneous abdominal fat mitochondrial DNA (mtDNA) and mitochondrial RNA (mtRNA), inflammation markers (soluble tumour necrosis factor receptors, high-sensitivity C reactive protein [hsCRP], interleukin-6 [IL-6], soluble vascular cell adhesion molecule 1), bone mineral density (BMD) of the hip and spine, HIV-1 RNA, CD4(+) T-cells and fasting metabolic parameters. RESULTS Fifty patients were enrolled (n=24 TDF switch; n=26 uridine); median age 48 years; 54% white; 86% male; limb fat 4,494 g. Baseline characteristics were similar between groups. In the NucleomaxX(®) arm, mtRNA increased (all P<0.001), hsCRP and IL-6 increased (both P=0.02), whereas fat mtDNA decreased without changes in limb fat. In the TDF-switch arm, fat mtDNA and inflammation markers did not change; however, significant increases in mtRNAs (P<0.001), limb fat (409 g; IQR -59-1,155) and CD4(+) T-cell count (P=0.03), and decreases in total and hip BMD (median -3.3%; IQR -5.1-0; P=0.005) were observed. Between-group changes were significant for fat mtDNA, hsCRP, IL-6, limb fat and hip BMD. No correlation was found between changes in limb fat and those of fat mtRNA, inflammation markers or protease inhibitor duration. CONCLUSIONS In HIV lipoatrophy, NucleomaxX(®) improved mtRNA, but worsened inflammation markers and fat mtDNA without changes in limb fat. Switching from a tNRTI to TDF for 48 weeks increased limb fat and fat mtRNA. Large decreases in total and hip BMD were seen after TDF switch.
ClinicalTrials.gov identifier: NCT00119379.
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Affiliation(s)
- Grace A McComsey
- University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH, USA.
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Weinberg ME, Roman MC, Jacob P, Wen M, Cheung P, Walker UA, Mulligan K, Schambelan M. Enhanced uridine bioavailability following administration of a triacetyluridine-rich nutritional supplement. PLoS One 2011; 6:e14709. [PMID: 21379380 PMCID: PMC3040752 DOI: 10.1371/journal.pone.0014709] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2010] [Accepted: 09/03/2010] [Indexed: 11/19/2022] Open
Abstract
Background Uridine is a therapy for hereditary orotic aciduria and is being investigated in other disorders caused by mitochondrial dysfunction, including toxicities resulting from treatment with nucleoside reverse transcriptase inhibitors in HIV. Historically, the use of uridine as a therapeutic agent has been limited by poor bioavailability. A food supplement containing nucleosides, NucleomaxX®, has been reported to raise plasma uridine to supraphysiologic levels. Methodology/Principal Findings Single- and multi-dose PK studies following NucleomaxX® were compared to single-dose PK studies of equimolar doses of pure uridine in healthy human volunteers. Product analysis documented that more than 90% of the nucleoside component of NucleomaxX® is in the form of triacetyluridine (TAU). Single and repeated dosing with NucleomaxX® resulted in peak plasma uridine concentrations 1–2 hours later of 150.9±39.3 µM and 161.4±31.5 µM, respectively, levels known to ameliorate mitochondrial toxicity in vitro. Cmax and AUC were four-fold higher after a single dose of NucleomaxX® than after uridine. No adverse effects of either treatment were observed. Conclusions/Significance NucleomaxX®, containing predominantly TAU, has significantly greater bioavailability than pure uridine in human subjects and may be useful in the management of mitochondrial toxicity.
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Affiliation(s)
- Melissa E Weinberg
- University of California San Francisco, San Francisco, California, United States of America.
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Abstract
BACKGROUND Lipoatrophy is prevalent on thymidine nucleoside reverse transcriptase inhibitors (tNRTIs). A pilot trial showed that uridine (NucleomaxX) increased limb fat. METHODS A5229 was a multicenter trial in which HIV-infected individuals with lipoatrophy on tNRTI regimens were randomized to NucleomaxX or placebo. Primary endpoint was change in limb fat from baseline to week 48. The study was powered to detect 400-g difference between arms at week 48. A stratified Wilcoxon rank-sum test was used to assess between-arm differences. RESULTS The 165 participants were 91% men, 62% white; median age 49 years, CD4 cell count 506 cells/μl, and limb fat 3037 g; 81% had HIV-1 RNA 50 copies/ml or less; 76% were on zidovudine (ZDV). Baseline characteristics were similar between groups. Only 59% completed 48 weeks of treatment; however, only three participants (one on uridine) discontinued due to toxicity (diarrhea). In intent to treat, there was no difference for changes in limb fat between treatments at week 24 or week 48. On as-treated analysis, uridine resulted in an increase in %limb fat vs. placebo (3.4 vs. -0.8%, P = 0.01) at week 24 but not at week 48 (1.8 vs. 3.8%, P = 0.93). Similar results were seen when limiting the analysis to patients with at least 80% adherence. The results were not related to severity of lipoatrophy or type of tNRTI. No changes were found in facial anthropometrics, fasting lipids, trunk fat, CD4 cell count, or HIV RNA. CONCLUSIONS We found a modest transient improvement in limb fat after 24 weeks of uridine. The lack of sustained efficacy at week 48 was not due to changes in adherence or reduction in sample size. Uridine was well tolerated and did not impair virologic control.
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Abstract
PURPOSE OF REVIEW Antiretroviral drugs are associated with hepatotoxicity. Progress in our knowledge on the prevalence, contributory factors and mechanisms is reviewed. RECENT FINDINGS Liver toxicity is highly prevalent and a major cause of hospitalization among HIV-infected individuals. Liver steatosis is probably more frequent in the setting of hepatitis C virus coinfection but is also seen in noncoinfected patients. Among the individual drugs, severe liver toxicity is more strongly associated with nevirapine, and the mitochondrial toxicity of some nucleoside analogues. Mitochondrial toxicity can also induce or contribute to steatohepatitis, with dietary uridine supplementation as a possible strategy of prevention. Atazanavir inhibits UDP-glucuronosyltransferase, which in Gilberts' syndrome has been associated with breast cancer. A UDP-glucuronosyltransferase gene promoter variant predisposes to hyperbilirubinemia. Tipranavir induces elevated transaminases more frequently than boosted comparator protease inhibitors. CCR5 inhibitors may predispose to hepatotoxic events by causing an imbalance in the cytokine response. SUMMARY Hepatotoxicity is associated with all classes of antiretroviral agents and continues to contribute to hospitalization.
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Chang KC, Oh JY, In YS, Kim MK, Shin KC, Wee WR, Lee JH, Park MG. Preliminary effects of oral uridine on the ocular surface in dry eye patients. J Korean Med Sci 2009; 24:701-7. [PMID: 19654956 PMCID: PMC2719204 DOI: 10.3346/jkms.2009.24.4.701] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Accepted: 10/25/2008] [Indexed: 11/23/2022] Open
Abstract
We designed a randomized, double blinded, 3-months controlled prospective clinical study to investigate effects of oral uridine on the ocular surface in dry eye patients. Twenty-seven patients who diagnosed as dry eye with lower than 5 mm of wetting in the Schirmer strip, with corneal epithelial erosion and who completely followed-up till 3 months were enrolled. Corneal-conjunctival fluorescein staining, non-anesthetic Schirmer test, impression cytology, and Ocular Surface Disease Index (OSDI) were evaluated in the experimental and placebo groups at the baseline, 1 and 3 months after start of medication in a double blinded manner. Fluorescein stain score of the cornea was markedly decreased in oral uridine group compared to the placebo group at 3 months after medication (P=0.032, Mann-Whitney U test). The Schirmer wetting score for the oral uridine group was significantly increased (P=0.001, Wilcoxon signed rank test) at 3 months and its difference between two groups was statistically significant (P=0.030, Mann-Whitney U test). OSDI scores were significantly decreased at 1 and 3 months in treatment group. Oral uridine is effective in treatment of dry eyes.
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Affiliation(s)
- Ki Cheol Chang
- Department of Ophthalmology, Seoul National University College of Medicine and Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Joo Youn Oh
- Department of Ophthalmology, Seoul National University College of Medicine and Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Youn Seok In
- Department of Ophthalmology, Seoul National University College of Medicine and Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Mee Kum Kim
- Department of Ophthalmology, Seoul National University College of Medicine and Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Ki Cheul Shin
- Department of Ophthalmology, Kunkuk University Hospital, Seoul, Korea
| | - Won Ryang Wee
- Department of Ophthalmology, Seoul National University College of Medicine and Seoul National University Hospital Clinical Research Institute, Seoul, Korea
| | - Jin Hak Lee
- Department of Ophthalmology, Seoul National University College of Medicine and Seoul National University Hospital Clinical Research Institute, Seoul, Korea
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Pharmacokinetics of Zidovudine and Lamivudine During Oral Uridine Supplementation With NucleomaxX. J Acquir Immune Defic Syndr 2008; 48:114-6. [DOI: 10.1097/qai.0b013e318160a67d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lebrecht D, Deveaud C, Beauvoit B, Bonnet J, Kirschner J, Walker UA. Uridine supplementation antagonizes zidovudine-induced mitochondrial myopathy and hyperlactatemia in mice. ACTA ACUST UNITED AC 2008; 58:318-26. [PMID: 18163507 DOI: 10.1002/art.23235] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Zidovudine is an antiretroviral nucleoside analog reverse transcriptase inhibitor that induces mitochondrial myopathy by interfering with the replication of mitochondrial DNA (mtDNA). Because zidovudine inhibits thymidine kinases, the mechanism of mtDNA depletion may be related to an impairment of the de novo synthesis of pyrimidine nucleotides, which are required building blocks of mtDNA. This study was undertaken to determine whether mitochondrial myopathy is a class effect of antiretroviral nucleoside analogs, and whether the muscle disease can be prevented by treatment with uridine as a pyrimidine nucleotide precursor. METHODS BALB/c mice were treated with zidovudine or zalcitabine. Some of the mice were cotreated with mitocnol, a dietary supplement with high uridine bioavailability. Mice hind limb muscles were examined after 10 weeks. RESULTS Zidovudine induced muscle fiber thinning, myocellular fat deposition, and abnormalities of mitochondrial ultrastructure. In mice treated with zidovudine, organelles contained low mtDNA copy numbers and reduced cytochrome c oxidase activity. The expression of the mtDNA-encoded cytochrome c oxidase I subunit, but not of nucleus-encoded mitochondrial proteins, was impaired. Zidovudine also increased the levels of myocellular reactive oxygen species and blood lactate. Uridine supplementation attenuated or normalized all pathologic abnormalities and had no intrinsic effects. Zalcitabine did not elicit muscle toxicity. CONCLUSION Our findings indicate that zidovudine, but not zalcitabine, induces mitochondrial myopathy, which is substantially antagonized by uridine supplementation. These results provide proof of the importance of pyrimidine pools in the pathogenesis of zidovudine myopathy. Since uridine supplementation is tolerated well by humans, this treatment strategy should be investigated in clinical trials.
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McComsey GA, O'Riordan M, Setzer B, Lebrecht D, Baron E, Walker UA. Uridine supplementation in HIV lipoatrophy: pilot trial on safety and effect on mitochondrial indices. Eur J Clin Nutr 2007; 62:1031-7. [PMID: 17538545 PMCID: PMC4105300 DOI: 10.1038/sj.ejcn.1602793] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Uridine abrogates mitochondrial toxicities of nucleoside reverse transcriptase inhibitor in adipocyte cell culture. We aim to study the effect of uridine supplementation on human adipocyte mitochondrial DNA (mtDNA) levels in subjects with human immunodeficiency (HIV) lipoatrophy. METHODS Sixteen patients with lipoatrophy on stavudine-containing antiretroviral therapy were enrolled, and received NucleomaxX, a dietary supplement with a high bioavailability of uridine (36 g TID every other day for 16 weeks). Patients were then followed off-uridine for another 16 weeks. Highly active antiretroviral therapy remained unchanged during the trial. RESULTS Fourteen patients completed the study. Two subjects dropped out before week 4 for study-unrelated reasons. No adverse events were noted throughout the study. HIV-1 RNA, CD4 counts, liver enzymes and hemoglobin remained unchanged. Body mass index, lactate, lipids, insulin and homeostasis model assessment of insulin resistance were unaltered. Fat and peripheral blood and mononuclear cell mtDNA levels did not correlate with each other and exhibited no changes throughout the study. Lipoatrophy scores by patients and physician improved significantly at weeks 16 and 32 compared to study entry. CONCLUSION In this pilot study, NucleomaxX was safe, well tolerated without apparent deleterious effect on HIV indices. In contrast to in vitro data, NucleomaxX did not lead to changes in fat or blood mtDNA levels.
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Affiliation(s)
- G A McComsey
- Department of Pediatrics, Rainbow Babies and Children's Hospital, Cleveland, OH 44106, USA.
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Susan-Resiga D, Bentley AT, Lynx MD, LaClair DD, McKee EE. Zidovudine inhibits thymidine phosphorylation in the isolated perfused rat heart. Antimicrob Agents Chemother 2007; 51:1142-9. [PMID: 17220403 PMCID: PMC1855461 DOI: 10.1128/aac.01227-06] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Zidovudine (AZT; 3'-azido-3'-deoxythymidine), a thymidine analog, has been a staple of highly active antiretroviral therapy. It is phosphorylated in the host to the triphosphate and functions by inhibiting the viral reverse transcriptase. However, long-term use of AZT is linked to various tissue toxicities, including cardiomyopathy. These toxicities are associated with mitochondrial DNA depletion, which is hypothesized to be caused by AZT triphosphate inhibition of mitochondrial DNA polymerase gamma. In previous work with isolated heart mitochondria, we demonstrated that AZT phosphorylation beyond the monophosphate was not detected and that AZT itself was a potent inhibitor of thymidine phosphorylation. This suggests an alternative hypothesis in which depletion of the TTP pool may limit mitochondrial DNA replication. The present work extends these studies to the whole cell by investigating the metabolism of thymidine and AZT in the intact isolated perfused rat heart. [3H]thymidine is converted to [3H]TTP in a time- and concentration-dependent manner. The level of [3H]TMP is low, suggesting that the reaction catalyzed by thymidine kinase is the rate-limiting step in phosphorylation. [3H]AZT is converted in a time- and concentration-dependent manner to AZT monophosphate, the only phosphorylated product detected after 3 h of perfusion. Both compounds display negative cooperativity, similar to the observations with cloned and purified mitochondrial thymidine kinase 2. The presence of AZT in the perfusate inhibits the phosphorylation of [3H]thymidine with a 50% inhibitory concentration of 24+/-4 microM. These data support the hypothesis that AZT-induced mitochondrial cardiotoxicity may be caused by a limiting pool of TTP that lowers mitochondrial DNA replication.
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Affiliation(s)
- Delia Susan-Resiga
- Indiana University School of Medicine-South Bend, South Bend, IN 46617, USA
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Lebrecht D, Vargas-Infante YA, Setzer B, Kirschner J, Walker UA. Uridine supplementation antagonizes zalcitabine-induced microvesicular steatohepatitis in mice. Hepatology 2007; 45:72-9. [PMID: 17187420 DOI: 10.1002/hep.21490] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Zalcitabine is an antiretroviral nucleoside analogue that exhibits long-term toxicity to hepatocytes by interfering with the replication of mitochondrial DNA (mtDNA). Uridine antagonizes this effect in vitro. In the present study we investigate the mechanisms of zalcitabine-induced hepatotoxicity in mice and explore therapeutic outcomes with oral uridine supplementation. BalbC mice (7 weeks of age, 9 mice in each group) were fed 0.36 mg/kg/d of zalcitabine (corresponding to human dosing adapted for body surface), or 13 mg/kg/d of zalcitabine. Both zalcitabine groups were treated with or without Mitocnol (0.34 g/kg/d), a dietary supplement with high bioavailability of uridine. Liver histology and mitochondrial functions were assessed after 15 weeks. One mouse exposed to high dose zalcitabine died at 19 weeks of age. Zalcitabine induced a dose dependent microvesicular steatohepatitis with abundant mitochondria. The organelles were enlarged and contained disrupted cristae. Terminal transferase dUTP nick end labeling (TUNEL) assays showed frequent hepatocyte apoptosis. mtDNA was depleted in liver tissue, cytochrome c-oxidase but not succinate dehydrogenase activities were decreased, superoxide and malondialdehyde were elevated. The expression of COX I, an mtDNA-encoded respiratory chain subunit was reduced, whereas COX IV, a nucleus-encoded subunit was preserved. Uridine supplementation normalized or attenuated all toxic abnormalities in both zalcitabine groups, but had no effects when given without zalcitabine. Uridine supplementation was without apparent side effects. CONCLUSION Zalcitabine induces mtDNA-depletion in murine liver with consequent respiratory chain dysfunction, up-regulated synthesis of reactive oxygen species and microvesicular steatohepatitis. Uridine supplementation attenuates this mitochondrial hepatotoxicity without apparent intrinsic effects.
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Affiliation(s)
- Dirk Lebrecht
- Department of Rheumatology and Clinical Immunology, Medizinische Universitätsklinik, Freiburg, Germany
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Sutinen J, Walker UA, Sevastianova K, Klinker H, Häkkinen AM, Ristola M, Yki-Järvinen H. Uridine Supplementation for the treatment of Antiretroviral Therapy-Associated Lipoatrophy: A Randomized, Double-Blind, Placebo-Controlled Trial. Antivir Ther 2007. [DOI: 10.1177/135965350701200113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background Highly active antiretroviral therapy (HAART) is associated with loss of subcutaneous fat (lipoatrophy) presumably due to mitochondrial toxicity of nucleoside reverse transcriptase inhibitors. In vitro, uridine abrogates thymidine analogue-induced toxicity in adipocytes. Methods A total of 20 patients with HAART-associated lipoatrophy were randomized to receive either a dietary uridine supplement (36 g three times a day for 10 consecutive days/month) or placebo, for 3 months. Body composition was measured using dual energy X-ray absorptiometry, magnetic resonance imaging and proton spectroscopy. Data are mean ± standard error of mean. Results The mean increases in limb fat (880 ±140 versus 230 ±270 g; P<0.05), intra-abdominal fat (210 ±80 versus -80 ±70 cm3; P<0.05) and total body fat (1,920 ±240 versus 240 ±520 g; P<0.01) were significantly greater in the uridine than in the placebo group. Within the uridine group, the changes from baseline to 3 months were statistically significant in total limb fat ( P<0.001), intra-abdominal fat ( P<0.05) and total body fat ( P<0.001). The proportion of limb fat to total fat increased from 18% to 25% ( P<0.05) in the uridine group. Liver fat content and lean body mass remained unchanged in both groups. High-density lipoprotein-cholesterol concentrations decreased in the uridine and increased in the placebo group, whereas fasting serum insulin concentrations did not change. Uridine supplementation was well tolerated and the virological effect of HAART was not affected. Conclusion Uridine supplementation significantly and predominantly increased subcutaneous fat mass in lipoatrophic HIV-infected patients during unchanged HAART.
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Affiliation(s)
- Jussi Sutinen
- Division of Diabetes, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
- Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Ulrich A Walker
- Department of Rheumatology and Clinical Immunology, Medizinische Universitätsklinik, Freiburg, Germany
| | - Ksenia Sevastianova
- Division of Diabetes, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
- Minerva Institute for Medical Research, Helsinki, Finland
| | - Hartwig Klinker
- Department of Medicine, Division of Infectious Diseases, Medizinische Poliklinik, University of Wuerzburg, Germany
| | - Anna-Maija Häkkinen
- Department of Oncology, Helsinki University Central Hospital, Helsinki, Finland
| | - Matti Ristola
- Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Hannele Yki-Järvinen
- Division of Diabetes, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
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Banasch M, Goetze O, Knyhala K, Potthoff A, Schlottmann R, Kwiatek MA, Bulut K, Schmitz F, Schmidt WE, Brockmeyer NH. Uridine supplementation enhances hepatic mitochondrial function in thymidine-analogue treated HIV-infected patients. AIDS 2006; 20:1554-6. [PMID: 16847412 DOI: 10.1097/01.aids.0000237373.38939.14] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Supplementation with uridine offers the possibility of a new and promising approach to nucleoside analogue reverse transcriptase inhibitor-associated mitochondrial toxicity. We investigated the metabolic effects of short-course treatment with the uridine-enriched food supplement NucleomaxX on hepatic mitochondrial function in thymidine-analogue treated HIV-infected patients. Mitochondrial function was assessed by a recently introduced non-invasive C-methionine breath test. NucleomaxX supplementation enhanced mitochondrial decarboxylation function reversibly but reproducibly in all patients. Repeated administration in shorter treatment intervals may maintain this effect.
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Affiliation(s)
- Matthias Banasch
- Department of Internal Medicine, St. Josef-Hospital, University of Bochum, Germany.
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Lynx MD, McKee EE. 3'-Azido-3'-deoxythymidine (AZT) is a competitive inhibitor of thymidine phosphorylation in isolated rat heart and liver mitochondria. Biochem Pharmacol 2006; 72:239-43. [PMID: 16720018 PMCID: PMC1482733 DOI: 10.1016/j.bcp.2006.04.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 04/06/2006] [Accepted: 04/06/2006] [Indexed: 11/25/2022]
Abstract
Long-term use of 3'-azido-3'-deoxythymidine (AZT) is associated with various tissue toxicities, including hepatotoxicity and cardiomyopathy, and with mitochondrial DNA depletion. AZT-5'-triphosphate (AZTTP) is a known inhibitor of the mitochondrial DNA polymerase gamma and has been targeted as the source of the mitochondrial DNA depletion. However, in previous work from this laboratory with isolated rat heart and liver mitochondria, AZT itself was shown to be a more potent inhibitor of thymidine phosphorylation (IC50 of 7.0+/-1.0 microM AZT in heart mitochondria and of 14.4+/-2.6 microM AZT in liver mitochondria) than AZTTP is of polymerase gamma (IC50 of >100 microM AZTTP), suggesting that depletion of mitochondrial stores of TTP may limit replication and could be the cause of the mitochondrial DNA depletion observed in tissues affected by AZT toxicity. The purpose of this work is to characterize the nature of AZT inhibition of thymidine phosphorylation in isolated rat heart and rat liver mitochondria. In both of these tissues, AZT was found to be a competitive inhibitor of the phosphorylation of thymidine to TMP, catalyzed by thymidine kinase 2. The inhibition constant (Ki) for heart mitochondria is 10.6+/-4.5 microM AZT, and for liver mitochondria Ki is 14.0+/-2.5 microM AZT. Since AZT is functioning as a competitive inhibitor, increasing thymidine concentrations may be one mechanism to overcome the inhibition and decrease AZT-related toxicity in these tissues.
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Affiliation(s)
| | - Edward E. McKee
- Address correspondence to: Edward E. McKee, 1234 Notre Dame Ave., South Bend, IN 46617, Tel: 574-631-7193; Fax: 574-631-7821; E-mail:
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Walker UA, Auclair M, Lebrecht D, Kornprobst M, Capeau J, Caron M. Uridine Abrogates the Adverse Effects of Antiretroviral Pyrimidine Analogues on Adipose Cell Functions. Antivir Ther 2006. [DOI: 10.1177/135965350601100109] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives Side effects of antiretroviral treatment such as lipoatrophy have been mainly attributed to mitochondrial toxicity of nucleoside reverse transcriptase inhibitors (NRTIs). We assessed whether uridine can abrogate the adverse effects of NRTIs on adipocyte functions. Methods 3T3-F442A preadipocytes were exposed to stavudine (d4T; 10 μM), zidovudine (ZDV; 1 μM), zalcitabine (ddC; 0.2 μM) or didanosine (ddI; 10 μM) in the absence or presence of uridine 21 days prior to and 7 days after induction of differentiation. Then, lipid accumulation (oil red staining), apoptosis (flow cytometry, PARP-cleavage), mitochondrial mass (Mitotracker) and DNA (mtDNA), cytochrome c oxidase (COX) subunits and mitochondrial membrane potential (JC-1) were quantified. Results Whereas ddI had no effects, d4T, ZDV and ddC significantly decreased cellular lipid accumulation (by 32%, 46% and 24%, respectively), increased apoptosis and induced mitochondrial depolarization. d4T, ZDV and ddC decreased adipocyte mtDNA (by 64%, 53% and 46%, respectively) and reduced the mtDNA encoded COX II subunit. Uridine (200 μM) had no intrinsic effect, but prevented all adverse effects of d4T, ZDV and ddC on adipocyte morphology, lipid staining, apoptosis, mtDNA depletion (partial prevention with ZDV), mitochondrial mass and membrane potential. The effects of uridine were concentration-dependent. Uridine also fully reverted established d4T toxicities despite continued d4T exposure. Conclusions Uridine supplementation protects adipocytes from the adverse effects of d4T, ZDV and ddC on lipid accumulation, cell survival and mitochondrial functions, suggesting that the toxic effects could be linked to intracellular depletion of uridine or its metabolites. Uridine is an interesting candidate in the prevention of NRTI-induced lipoatrophy in vivo.
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Affiliation(s)
- Ulrich A Walker
- Medizinische Universitätsklinik, Department of Rheumatology and Clinical Immunology Freiburg, Germany
| | - Martine Auclair
- INSERM U680, Université Pierre et Marie Curie, Faculté de Médecine, UPMC, Paris, France
| | - Dirk Lebrecht
- Medizinische Universitätsklinik, Department of Rheumatology and Clinical Immunology Freiburg, Germany
| | - Michel Kornprobst
- INSERM U680, Université Pierre et Marie Curie, Faculté de Médecine, UPMC, Paris, France
| | - Jacqueline Capeau
- INSERM U680, Université Pierre et Marie Curie, Faculté de Médecine, UPMC, Paris, France
- Hopital Tenon, AP-HP, Paris, France
| | - Martine Caron
- INSERM U680, Université Pierre et Marie Curie, Faculté de Médecine, UPMC, Paris, France
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Walker UA, Venhoff N. Uridine in the Prevention and Treatment of Nrti-Related Mitochondrial Toxicity. Antivir Ther 2005. [DOI: 10.1177/135965350501002s13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Long-term side effects of antiretroviral therapy are attributed to the mitochondrial (mt) toxicity of nucleoside analogue reverse transcriptase inhibitors (NRTIs) and their ability to deplete mtDNA. Studies in hepatocytes suggest that uridine is able to prevent and treat mtDNA depletion by pyrimidine NRTIs [zalcitabine (ddC) and stavudine (d4T)] and to fully abrogate hepatocyte death, elevated lactate production and intracellular steatosis. Uridine was also found to improve the liver and haematopoietic toxicities of zidovudine (AZT), which are unrelated to mtDNA depletion, and to prevent neuronal cell death induced by ddC. Most recently, uridine was found to prevent the onset of a lipoatrophic phenotype (reduced intracellular lipids, increased apoptosis, mtDNA depletion and mt depolarization) in adipocytes incubated long-term with d4T and AZT. Various steps of mt nucleoside utilization may be involved in the protective effect, but competition of uridine metabolites with NRTIs at polymerase y or other enzymes is a plausible explanation. Pharmacokinetic studies suggest that uridine serum levels can be safely increased in humans to achieve concentrations which are protective in vitro (50–200 μM). Uridine was not found to interfere with the antiretroviral activity of NRTIs. Mitocnol, a sugar cane extract which effectively increases uridine in human serum, was beneficial in individual HIV patients with mt toxicity and is now being tested in placebo-controlled randomized trials. Until these data become available, the risk-benefit calculation of using uridine should be individualized. The current safety data justify the closely monitored use of uridine in individuals who suffer from mt toxicity but who cannot be switched to less toxic NRTIs.
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Affiliation(s)
- Ulrich A Walker
- Department of Rheumatology and Clinical Immunology, Medizinische Universitätsklinik, Freiburg, Germany
| | - Nils Venhoff
- Department of Rheumatology and Clinical Immunology, Medizinische Universitätsklinik, Freiburg, Germany
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