Typically, tobacco companies market harm-reduction cigarettes as being safer than traditional "full-flavored" brands, leading many smokers to conclude that the use of harm-reduction brands lowers their exposure to toxicants.
But a UC Riverside study now shows that smoke from these "light" or "low-yield" harm-reduction cigarettes retains toxicity and that this toxicity can affect prenatal development.
"Many chemicals found in harm-reduction cigarette smoke have not been tested, and some are listed by manufacturers as safe," said Prue Talbot, a professor of cell biology who led the study. "But our tests on mice clearly show that these chemicals adversely affect reproduction and associated development processes. The effects are likely to be the same in humans, in which case pregnant women would be particularly vulnerable to the effect of smoke from these cigarettes."
Talbot's research team used mouse embryonic stem cells (mESCs) as a model for pre-implantation embryos—embryos that have not yet implanted in the wall of the uterus—and compared the toxicity on these cells of cigarette smoke emanating from traditional and harm-reduction brands.
Further, they studied the effects on the mESCs of two kinds of cigarette smoke: mainstream smoke, which is smoke actively inhaled by smokers; and sidestream smoke, which is smoke that burns off the end of a cigarette.
They found that both kinds of smoke from traditional and harm-reduction cigarettes are toxic to pre-implantation embryos and can retard growth or kill embryonic cells at this stage of development. Equally surprising to them was their discovery that mainstream smoke and sidestream smoke from harm-reduction cigarettes are more potent than the corresponding smoke from traditional brands of cigarettes.
"This result was unexpected since harm reduction brands purportedly have lower concentrations of toxicants," Talbot said.
"Dr. Talbot's work significantly enhances our understanding of the harmful effects of smoking on very early pregnancy," said Olga Genbacev, a senior scientist in the Department of Obstetrics, Gynecology and Reproductive Sciences at UC San Francisco, who was not involved in the research. "This study for the first time sends a clear message to nonsmoking women of reproductive age who are planning to become pregnant that they must avoid exposure to sidestream smoke."
Study results appear in the journal Human Reproduction (published online, Nov. 29). The hardcopy version of the research paper is scheduled to appear in January 2009.
"Clearly, the tobacco companies have not eliminated all toxins from harm-reduction brands of cigarettes," said Talbot, who also is the director of the UCR Stem Cell Center. "We found that both mainstream and sidestream smoke from traditional and harm-reduction cigarettes hindered the attachment of mESCs to extracellular materials. Such attachment is crucial to normal embryonic development. Moreover, cell survival and proliferation—also necessary for embryonic growth—were hindered as well."
The researchers' experiments on the mESCs showed, too, that on a per puff basis sidestream smoke was more potent than mainstream smoke in both traditional and harm-reduction brands of cigarettes.
"This may be because sidestream smoke is produced at a lower temperature and therefore contains higher concentrations of toxicants," Talbot said.
When she and her colleagues performed the experiments directly on pre-implantation mouse embryos that had been cultured for one hour in mainstream or sidestream smoke solutions from a harm-reduction brand, they found that the effect of smoke on the embryos was similar to the effect it had on the mESCs.
"This strongly supports our use of embryonic stem cells as a valuable and effective model to study embryo toxicity during pre-implantation development," said Sabrina Lin, a graduate student in the Cell, Molecular and Developmental Biology Program working towards her doctoral degree, and the first author of the research paper. "This means we can use human embryonic stem cells to draw conclusions about the effect of cigarette smoke on pre-implantation human embryos."
Next in their research, Talbot and Lin plan to conduct their experiments on human embryonic stem cells.
"To relate this research more strongly to humans, we have to use human embryonic stem cells," Talbot said. "Sabrina has already started working on them, and her preliminary results are similar to those with mESC."
Iqbal Pittalwala | EurekAlert!
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Materials Sciences
21.08.2017 | Health and Medicine
21.08.2017 | Materials Sciences