No abstract

3'-azido-3'-deoxythymidine (AZT) is given to pregnant women positive for the human immunodeficiency virus type 1 (HIV-1) to reduce maternal-fetal viral transmission. To explore fetal mitochondrial consequences of this exposure, pregnant Erythrocebus patas monkeys were given daily doses of 1.5 mg (21% of the human daily dose) and 6.0 mg (86% of the human daily dose) of AZT/kg body weight (bw), for the second half of gestation. At term, electron microscopy of fetal cardiac and skeletal muscle showed abnormal and disrupted sarcomeres with myofibrillar loss. Some abnormally shaped mitochondria with disrupted cristae were observed in skeletal muscle myocytes. Oxidative phosphorylation (OXPHOS) enzyme assays showed dose-dependent alterations. At the human-equivalent dose of AZT (6 mg of AZT/kg bw), there was an approximately 85% decrease in the specific activity of NADH dehydrogenase (complex I) and three- to sixfold increases in specific activities of succinate dehydrogenase (complex II) and cytochrome-c oxidase (complex IV). Furthermore, a dose-dependent depletion of mitochondrial DNA levels was observed in both tissues. The data demonstrate that transplacental AZT exposure causes cardiac and skeletal muscle mitochondrial myopathy in the patas monkey fetus.

Uterine fluid from unilaterally pregnant ewes contains activity inhibitory to lymphocyte proliferation. The molecules responsible for this activity may thereby regulate uterine immune responses during pregnancy. The purpose of the experiment described here was to identify the major protein in uterine fluid responsible for this activity. When uterine fluid was fractionated by a combination of cation exchange chromatography, gel filtration, and lectin affinity chromatography, the majority of the lymphocyte activity co-migrated with a pair of proteins previously identified as related, serpin-like glycoproteins. Together, this pair of proteins, called the uterine milk proteins (UTM-proteins), are the predominant endometrial secretory protein produced under the influence of progesterone. Preparations of uterine protein highly enriched for the UTM-proteins inhibited lymphocyte proliferation induced by phytohemagglutinin, concanavalin A, and mixed lymphocyte reactions but did not inhibit proliferation induced by pokeweed mitogen. In some experiments, UTM-proteins also reduced viability of cultured lymphocytes. Another previously described lymphocyte-inhibitory factor, megasuppressin, was also observed. Megasuppressin, which eluted at an apparent molecular weight of greater than 4 x 10(6) even after treatment with urea, guanidine-HCl, and beta-mercaptoethanol, was a more potent inhibitor of lymphocyte proliferation than UTM-proteins. Megasuppressin is not very abundant, however, and probably is responsible for only a small fraction of the lymphocyte inhibitory activity in uterine fluid. The majority of lymphocyte-inhibitory activity is caused by the UTM-proteins or by a molecule that co-purifies in trace amounts with UTM-proteins.

Results strengthen the thesis that UTMP are physiologically relevant immunoregulatory molecules. Nonetheless, effects on skin-fold responses indicate that actions of UTMP can be more complex than would be predicted based on the proteins only having a single biological effect.

Mitochondrial toxicity was assessed in the brains of developing Erythrocebus patas monkey fetuses exposed in utero to the nucleoside analogue drug zidovudine (3'-azido-3'deoxythymidine or AZT). Pregnant E. patas monkeys were given 0 (n = 5), 10 (n = 3), and 40 (n = 3) mg of AZT/day, equivalent to 21 and 86% of the human daily dose, for the last half (about 10 weeks) of gestation. Mitochondria were isolated from fetal cerebrum and cerebellum at birth and mitochondrial morphology was examined in these tissues by transmission electron microscopy (TEM). Oxidative phosphorylation (OXPHOS) enzyme specific activities were measured spectrophotometrically. Mitochondrial DNA (mtDNA) integrity and quantity were determined by Southern blot and slot blot analysis. In the cerebral mitochondria, reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase (complex I) specific activity decreased by 25% in monkeys treated with 40 mg of AZT/day compared with unexposed monkeys (p > or = .05). At the same AZT dose in the cerebral mitochondria, succinate dehydrogenase (complex II) and cytochrome c reductase (complex IV)-specific activities showed dose-dependent increases (p > or = .05), compared with those in controls. In the cerebellum, no difference was seen in mitochondrial OXPHOS enzyme activities between unexposed and exposed fetuses. Furthermore, TEM demonstrated no difference in mitochondrial morphology in frontal cerebrum or cerebellum from unexposed and exposed fetuses, and all fetuses had similar amounts of mtDNA in both tissues. Cerebral mtDNA degradation was noted in the highest AZT dosage group, whereas mtDNA from cerebellum was uneffected. Thus, in fetal patas monkeys given a human equivalent daily dose of AZT during the last half of pregnancy, mitochondria in the fetal cerebrum appear to sustain moderate damage, while the fetal cerebellum mitochondria were not effected.