University of California study links early nicotine exposure to immune changes

A study led by the University of California, Santa Cruz, has found that nicotine exposure during pregnancy and early postnatal life causes long-term changes to the hematopoietic stem cells and the developing immune system in mice.

Published in the journal ‘Stem Cell Reports’, the research indicates that offspring exposed to nicotine possessed fewer hematopoietic stem cells, which are responsible for producing mature immune cells. Researchers also identified altered gene expression patterns regulating the immune system within these cells. These changes persisted into adulthood, even though nicotine exposure ceased shortly after birth.

While the effects remained largely invisible under normal conditions—with mice maintaining normal circulating immune cell counts—the impact became evident during infection. Exposed mice had fewer macrophages in their lungs, a primary line of defense. When later infected with the influenza virus, these mice exhibited more intense inflammation and increased immune cell migration to the lungs, resulting in more severe lung tissue damage and greater weight loss.

Researchers noted that while these mouse model results cannot be directly applied to humans, the findings raise significant questions regarding nicotine exposure via products such as e-cigarettes and nicotine replacement therapies during pregnancy and early life.