Speaker
Description
Epidemiological studies have indicated an association between exposure to extremely low-frequency magnetic fields (ELF-MFs) and the development of childhood leukemia. However, further research is necessary because the causal relationship remains unclear. The most common type of childhood leukemia is acute B-lymphoblastic leukemia, which results from the dysregulated differentiation of B-progenitors and their abnormal proliferation. Because acute B-lymphoblastic leukemia does not develop spontaneously in commercially available rodent models, indicating that leukemogenic processes are associated with interspecies differences between humans and rodents, we have been evaluating the effects of MF exposure using human cells. We first performed in vitro experimental studies to elucidate whether ELF-MF exposure could influence leukemogenesis in humans. The results of MF exposure during the differentiation process from human iPS or primary cells suggested that 50 Hz MF exposure at 300 mT may not affect the human differentiation process from mesodermal cells to B-cell lineages. Next, we applied humanized mice that engrafted human hematopoietic stem progenitor cells and imitated human hematopoietic system in the mice to MFs exposure experiments. An animal exposure system that can stably generate uniform 50 Hz MFs of up to 5 mT(rms) has been newly fabricated in our laboratory. Two months of exposure tests have been completed, and we evaluate the effects of 50 Hz MF on the human hematopoietic system in humanized mice. Our continuous efforts should contribute to understanding the possible causal relationship between ELF-MFs and childhood leukemia.
