RESUMEN
Several systemic and cellular markers of 3'-azido-3'-dideoxythymidine (AZT) metabolism and AZT incorporation into nuclear DNA were measured in cord blood from uninfected infants born to HIV-1-infected mothers receiving prepartum therapies based on AZT or AZT in combination with 2',3'-dideoxy-3'-thiacytidine (3TC). In addition, the relationships among these pharmacological end points, levels of AZT-DNA incorporation, and the previously reported mutagenic responses in these infants were evaluated. AZT- and 3TC-specific radioimmunoassays (RIAs), or HPLC coupled with AZT-RIA, were used to measure plasma levels of AZT and the AZT-glucuronide, and cellular levels of AZT, phosphorylated AZT, and DNA incorporation of AZT or 3TC in cord blood mononuclear cells from treated infants compared with unexposed controls born to HIV-uninfected mothers. Fewer infants had detectable AZT-DNA incorporation levels in the group exposed to AZT (71%; n = 7) compared with those receiving AZT-3TC (100%; n = 21), and the mean AZT-DNA incorporation for AZT-exposed infants (14.6 +/- 6.3 AZT/10(6) nucleotides) was significantly lower than that in AZT-3TC exposed infants (51.6 +/- 10.2 AZT/10(6) nucleotides; P = 0.028). Low levels of 3TC-DNA incorporation found in a few AZT-3TC-exposed newborns correlated with AZT-DNA incorporation values in the same samples. Among the metabolites studied, there were positive correlations between levels of AZT-diphosphate and AZT-triphosphate, and AZT-triphosphate and AZT-DNA incorporation, in nucleoside analog-exposed infants. Levels of AZT-DNA incorporation, however, did not correlate well with the reported frequencies of somatic mutations in the same population of nucleoside analog-treated children. While these data support the continued use of AZT-based therapies during pregnancy, infants receiving prepartum AZT should be monitored long-term for adverse health effects.
Asunto(s)
Fármacos Anti-VIH/farmacocinética , Daño del ADN , Leucocitos Mononucleares/metabolismo , Inhibidores de la Transcriptasa Inversa/farmacocinética , Zidovudina/farmacocinética , Fármacos Anti-VIH/sangre , Fármacos Anti-VIH/uso terapéutico , Biomarcadores/análisis , ADN/metabolismo , Femenino , Sangre Fetal/metabolismo , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/prevención & control , Humanos , Recién Nacido , Lamivudine/farmacocinética , Intercambio Materno-Fetal , Embarazo , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Complicaciones Infecciosas del Embarazo/prevención & control , Inhibidores de la Transcriptasa Inversa/sangre , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Zidovudina/sangre , Zidovudina/uso terapéuticoRESUMEN
The genotoxicity of zidovudine (AZT) based treatments was investigated in human H9 lymphoblastoid cells in an in vitro study and in red blood cells (RBCs) from perinatally exposed HIV-1-infected mothers and their infants in an observational cohort study. Exposure of H9 cells for 24 hr to AZT produced dose-dependent increases in Comet assay tail moment (TM) when electrophoresed at pH 13.0, but not at pH 12.1 or pH 8.0, suggesting that DNA damage was via alkali-labile lesions and not double-stranded DNA strand breaks. The TM dose response at pH 13.0 correlated directly with AZT-DNA incorporation determined by AZT-radioimmunoassay. Levels of DNA damage in utero, measured by Comet assay TM, were similar in cord blood mononuclear cells of nucleoside analog-exposed newborns (n = 43) and unexposed controls (n = 40). In contrast, the glycophorin A (GPA) somatic cell mutation assay (which screens for large-scale DNA damage in RBCs) showed clear evidence that GPA N/N variants, arising from chromosome loss and duplication, somatic recombination, and gene conversion, were significantly elevated in mother-child pairs receiving prepartum AZT plus lamivudine (3TC). Cord blood from newborns exposed to AZT-3TC had GPA N/N variant frequencies of 4.7 +/- 0.7 (mean +/- SE) x 10(-6) RBCs (n = 26 infants) compared with 2.2 +/- 0.3 x 10(-6) RBCs for unexposed controls (n = 30 infants; P < 0.001). Elevations in GPA N/N variants generally persisted through 1 year of age in nucleoside analog-exposed children. Overall, the mutagenic effects found in mother-child pairs receiving AZT-based treatments justify their surveillance for long-term genotoxic consequences.
Asunto(s)
Fármacos Anti-VIH/toxicidad , Lamivudine/toxicidad , Inhibidores de la Transcriptasa Inversa/toxicidad , Zidovudina/toxicidad , Fármacos Anti-VIH/administración & dosificación , Fármacos Anti-VIH/uso terapéutico , Línea Celular , Ensayo Cometa , Combinación de Medicamentos , Eritrocitos/efectos de los fármacos , Femenino , Glicoforinas/genética , Humanos , Lactante , Recién Nacido , Lamivudine/administración & dosificación , Lamivudine/uso terapéutico , Leucocitos/efectos de los fármacos , Intercambio Materno-Fetal , Pruebas de Mutagenicidad , Mutación , Embarazo , Inhibidores de la Transcriptasa Inversa/administración & dosificación , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Zidovudina/administración & dosificación , Zidovudina/uso terapéuticoRESUMEN
OBJECTIVE: Although most uninfected infants born to women infected with HIV-1 show no clinical evidence of mitochondrial compromise, mitochondrial dysfunction has been reported in children born to women receiving zidovudine and/or lamivudine during pregnancy. In this pilot study we examined mitochondrial integrity in HIV-1-uninfected infants born to HIV-1-infected women receiving Combivir during pregnancy. DESIGN: : Samples of umbilical cord and cord blood were obtained from HIV-1-uninfected infants born to either HIV-1-infected women receiving Combivir therapy during pregnancy (n = 10) or HIV-1-uninfected women (n = 9). METHODS: Mitochondrial morphological integrity was examined in umbilical cords (n = 16) by electron microscopy and mtDNA quantity was determined in DNA from cord blood (n = 18) and umbilical cord (n = 18) by PCR-chemiluminescence immunoassay detection. RESULTS: In umbilical cords from six of nine infants born to HIV-1-infected mothers taking Combivir moderate to severe mitochondrial morphological damage was observed (P = 0.011), while none of seven unexposed infants showed similar damage. Compared to unexposed infants, statistically significant mtDNA depletion was observed in umbilical cord (P = 0.006) and cord blood (P = 0.003) from drug-exposed infants. CONCLUSIONS: A cohort of HIV-1-uninfected Combivir-exposed infants with no clinical symptoms showed morphological and molecular evidence of mitochondrial damage.