Electronic cigarette (e-cigarette) use is on the rise worldwide and is particularly attractive to young people and as a smoking substitute by pregnant woman. There is a perception in pregnant women and women of child-bearing age that the use of e-cigarettes (vaping) is safer than smoking tobacco cigarettes during pregnancy. However, there is little evidence to support this perception. Here, we examined the offspring from mouse dams that had been exposed during and after pregnancy to ambient air (sham) ( n = 8), e-cigarette aerosols with nicotine ( n = 8), or e-cigarette aerosols without nicotine ( n = 8). Offspring underwent cognitive testing at 12 weeks of age and epigenetic testing of brain tissues at 1 day, 20 days, and 13 weeks after birth. The findings showed deficits in short-term memory, reduced anxiety, and hyperactivity in offspring following maternal e-cigarette exposure using the novel object recognition and elevated plus maze tests. In addition, global DNA methylation was increased in the brains of offspring soon after birth. Using a quantitative-PCR array specific to chromatin modification enzymes on genomic DNA and histones,13 key genes were identified to be significantly altered in the offspring brains from the e-cigarette groups compared to the nonexposed groups. The changes to genes Aurka, Aurkb, Aurkc, Kdm5c, Kdm6b, Dnmt3a, Dnmt3b, and Atf2, all associated with modulating neurological activity, were validated using RT-qPCR. In conclusion, in a mouse model, maternal exposure to e-cigarette aerosols resulted in both cognitive and epigenetic changes in offspring. This suggests that the use of e-cigarettes during pregnancy may have hitherto undetected neurological consequences on newborns.
Increasing evidence indicates the potential of olfactory ensheathing cells (OECs) for treating spinal cord injuries. The present study compared proliferation and migration of adult rat and human OECs transplanted into the spinal cord of athymic (immunodeficient) rats. OECs were purified from the nasal lamina propria and prelabeled with a cytoplasmic dye. After OEC injection into the thoracic spinal cord, animals were perfused 4 hr, 24 hr, and 7 days later. Both rat and human OECs showed similar migration. Cells were seen leaving the injection site after 4 hr, and by 7 days both rat and human OECs had migrated approximately 1 mm rostrally and caudally within the cord (rat: 1,400 +/- 241 microm rostral, 1,134 +/- 262 microm caudal, n = 5; human: 1,337 +/- 192 microm rostral, 1,205 +/- 148 microm caudal, n = 6). Proliferation of transplanted OECs was evident at 4 hr, but most had ceased dividing by 24 hr. In 10 animals, the spinal cord was injured by a contralateral hemisection made 5 mm rostral to the transplantation site at the time of OEC transplantation. After 7 days, macrophages were numerous both around the injury and at the transplantation site. In the injured cord, rat and human OECs migrated for shorter distances, in both rostral and caudal directions (rat: 762 +/- 118 microm rostral, 554 +/- 142 microm caudal, n = 4; human: 430 +/- 55 microm rostral, 399 +/- 161 microm caudal, n = 3). The results show that rat and human OECs rapidly stop dividing after transplantation and have a similar ability to survive and migrate within the spinal cord of immunocompromised hosts. OECs migrated less in animals with a concomitant contralateral hemisection.
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