Cigarette smoke from conventional and harm reduction cigarettes inhibits proliferation of neural stem cells

Cigarette smoke, a mixture of over 7,000 chemicals, can affect development of the nervous system prenatally, which can produce cognitive problems in children after birth. The purposes of this study were to determine if chemicals in mainstream (MS) and side-stream (SS) cigarette smoke adversely affect proliferation of neural stem cells, which could explain the effects observed in humans, and to compare the potency of smoke from harm reduction vs. conventional cigarettes. Mouse neural stem cells (mNSC, clone C17.2, generously provided by Dr. Evan Snyder) were incubated in MS (smoke actively inhaled by the smoker) and SS (smoke burning off of the tip of a cigarette) smoke solutions from Marlboro Red, Marlboro Light, and Quest cigarettes. The cells were incubated in different concentrations of smoke solution (range = 0.001, 0.01 and 0.1 puff equivalents) for 48 hours at 37 o C, 5% CO2, and 95% relative humidity in a BioStation CT, and images of multiple fields were taken every 4 hours. The time-lapse videos were then analyzed using confluency recipes (which measures cell proliferation) created using the CL-Quant software. The results show inhibition of proliferation for most treatments, with SS smoke being more potent than MS smoke. The results also show that smoke from a ―harm reduction‖ brand (Marlboro light) was a more potent inhibitor of proliferation than smoke from a conventional brand (Marlboro red). These data support the idea that cognitive deficiencies that appear after birth in humans could be caused by prenatal cigarette smoke exposure leading to decreased proliferation of NSC. A Venture Into Literary Translation: Guy de Maupassant from French to English