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The results of studies conducted by researchers from the College of Medicine at Florida State University suggest that exposure to nicotine in men could result in cognitive deficits in their children and grandchildren. Research has shown that the addition of nicotine to the drinking water of male mice has resulted in epigenetic changes in sperm genes that may impact the major pathways of neurodevelopment. The immediate offspring of these male mice exposed to nicotine exhibited hyperactivity, attention deficit, and cognitive problems typical of those encountered in Attention Deficit Hyperactivity Disorder ( ADHD) and autism spectrum disorder in humans. The grandchildren of fathers exposed to nicotine also exhibited learning deficits, suggesting that at least some of the adverse effects badociated with nicotine can be pbaded down from generation to generation.
"Our data suggest that some of the cognitive impairments noted today by Dr. Jim Betty and Chair Rodeep Bhide, Dr. Jim Betty Ann Rodgers, a leading researcher in developmental neuroscience at the Faculty of Medicine, explain that that this generation of children and adults is attributable to the environmental damage suffered a generation or two ago. "Smoking was more common and more easily accepted by the population in the 1940s, 1950s and 1960s compared to aujourd & # 39; hui. Could this exposure prove to be a marked increase in the number of diagnoses of neurodevelopmental disorders such as ADHD and autism? "[19659002] The Florida State University team and colleagues at Harvard Medical School published their findings in PLOS Biology in an article entitled "Nicotine exposure of male mice causes behavioral alteration in several generations of offspring."
Studies have shown that nicotine use by pregnant women was badociated with an increased risk of behavioral problems in their children and in subsequent generations, the authors write, but in reality, smoking is more prevalent among men than women, and that studies in humans have suggested that parental cigarette consumption may increase the risk of ADHD in their children, in humans can not completely separate the effects of smoking in parents. environmental factors. ADHD and nicotine addiction often go hand in hand, and ADHD tends to spread in families, so it is difficult to separate the role of paternal ADHD from paternal smoking on behavioral changes seen in offspring.
Effects of paternal nicotine on offspring, the team exposed male nicotine mice in their drinking water for 12 weeks, then raised the mice with naive females to the drug. Male and female offspring (F1) were then bred with drug-naive partners to produce a second generation (F2) of animals from fathers exposed to nicotine.
Tests in the resulting litters showed that male and female F1 offspring of fathers exposed to nicotine exhibited increased spontaneous locomotor activity and deficits in inversion learning. Male offspring also showed "significant deficits in attention, monoamine content in the brain and the expression of dopamine receptor mRNA," commented L & # 39; team. And while hyperactivity phenotypes and attention deficit manifested in F1 mice were not transmitted to second-generation offspring, male F2 mice had deficits in mice. inversion learning.
An examination of spermatozoa of fathers exposed to nicotine showed changes. overall methylation of DNA, and in particular modifications of DNA methylation at the promoters of the dopamine D2 receptor gene. Dopamine receptors play a key role in neurodevelopmental processes. "The methylation of nicotine-mediated sperm DNA at the dopamine receptor-promoting regions could constitute a plausible epigenetic mechanism of transgenerational transmission of the effects of paternal exposure to nicotine", [19659002] "epigenetic changes," comments Dr. Deirdre MCarthy, co-author of the College of Medicine "This includes the dopamine D2 gene, which plays an important role in the development and learning of the brain It's probably the source of the cognitive deficits found in their descendants. "
The fact that only a fraction of the apparent deficits in F1 children had appeared. F2 progeny were also found that "at least some of the deleterious effects of nicotine exposure may be transient," they continue. that the team recognizes that additional research will be required. "These findings underscore the need to broaden the current focus of research and public policy targeting the exposure of nicotine-pregnant mothers, putting a more equitable focus on maternal and maternal exposure." from father to nicotine. "
"I believe that the results of our study may have Dr. Bhide added," Doctors can not warn men that their smoking could harm the unborn child, even if the mother never smoked. I think our study puts this in the foreground. "
In the past two weeks, researchers at the Wexner Medical Center at Ohio State University independently reported work on mice, which showed that a father's level of exercise before conception could last a long time The effects on the metabolic health of their children.A team led by Kristin Stanford, Ph.D., raised obese male mice, fed diet, with a high diet, who were either sedentary or in open access, with female mice fed found that while the offspring of sedentary obese fathers had more fat and showed an intolerance increased glucose intake than that of fathers fed normal chow diet, paternal exercise suppressed the effects of the high-fat father diet, and that their offspring was better demonstrated glucose metabolism, decreased body weight and decreased fat mbad.
"This is really interesting," says Dr. Stanford, "the offspring of fathers fed a diet rich in grain, so they were more intolerant to glucose. But exercise has negated this effect. When the father was active, even with a high-fat diet, we saw an improvement in the metabolic health of their adult offspring. "
An examination of fathers' sperm showed that the high-fat diet was badociated with a decrease in sperm motility and multiple changes in small RNA sperm, which could be reversed by physical training. "We've seen a big shift in their small RNA profile," Dr. Stanford adds, "Now we want to know exactly what small RNAs are responsible for these metabolic improvements, where it's happening in offspring and why."
studies were reported in Diabetes ("Paternal exercise improves glucose metabolism in adult children"). Researchers at Ohio State University believe that their mouse studies could be of direct interest to humans. Dr. Stanford explains, "It's possible that this translates to humans. We know that in adult men, obesity impairs testosterone levels, sperm count and motility, as well as the number of live births … If we ask someone who is preparing to have a child who exercises moderately, even for a month before conception, which could have a significant effect on the health of their sperm and on the long-term metabolic health of their children. "
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