Smoking e-cigarettes can alter hundreds of genes needed for immune defence, study says
Vaping may affect many more genes than smoking regular cigarettes; in other health news, the improved memory recall of runners may be due to a specific protein, and more fibre could reduce the severity of food allergies
Vaping affects genes involved in upper airway immune defence – hundreds more than smoking regular cigarettes – according to a new study from the University of North Carolina’s School of Medicine.
Several of these changes in the epithelial cells that line the respiratory tract are likely to increase the risk of bacterial infections, viruses and inflammation, according to the report in the American Journal of Physiology.
The study involved 13 non-smokers, 14 smokers and 12 e-cigarette users. Each participant kept a journal documenting their cigarette or e-cigarette use, and their urine and blood samples were analysed. After about three weeks, researchers took samples from the nasal passages of each participant to analyse the expression of genes important for immune responses.
The researchers found smoking cigarettes decreased the gene expression of 53 genes important for the immune response of epithelial cells compared to non-smokers. Using e-cigarettes decreased the gene expression of 358 genes important for immune defence – including all 53 genes implicated in the smoking group.
Lead researcher Ilona Jaspers says the findings cannot yet be linked to long-term health effects of e-cigarette use or the risk of diseases usually associated with long-term cigarette smoking.
“We know that diseases like COPD [chronic obstructive pulmonary disease], cancer and emphysema usually take many years to develop in smokers,” Jaspers says. “But people have not been using e-cigarettes for very long. So we don’t know yet how the effects of e-cigarette use might manifest in 10 or 15 years.”
Running releases protein associated with improved memory in mice
Studies have shown that running boosts memory recall – but why? New research in the US and Germany points to a particular protein called cathepsin B.
In the study published in the journal Cell Metabolism, normal mice and mice unable to make the protein ran on a wheel before taking a memory test. Normal mice showed better recall ability for new information, while mice unable to make cathepsin B could not recall the information at all.
“Nobody has shown before cathepsin B’s effect on spatial learning,” says senior author Henriette van Praag, a neuroscientist at the US National Institute on Ageing. “We also have converging evidence from our study that cathepsin B is upregulated in blood by exercise for three species – mice, Rhesus monkeys and humans. Moreover, in humans who exercise consistently for four months, better performance on complex recall tasks, such as drawing from memory, is correlated with increased cathepsin B levels.”
She adds: “People often ask us, how long do you have to exercise, how many hours? The study supports that the more substantial changes occur with the maintenance of a long-term exercise regimen.”
Mice fed more fibre have less severe food allergies
Having more fibre could reduce one’s risk of food allergies and their severity, according to a new study by Australian researchers.
Monash University scientists have found the development of food allergies in mice linked to what their gut bacteria are being fed. Rodents that received a diet of average calorie, sugar and fibre content from birth were shown to have more severe peanut allergies than those that received a high-fibre diet. The researchers show that gut bacteria release a specific fatty acid in response to fibre intake, which eventually impacts allergic responses via changes to the immune system.
“We felt that the increased incidence of food allergies in the past 10 years had to relate back to our diet and our own microbiome rather than a lack of exposure to environmental microbes – the so-called ‘hygiene hypothesis’,” says the study’s co-senior author and immunologist Laurence Macia.
The researchers express cautious optimism that their results can be effective in humans, and further preclinical trials would be required before studying the fibre-allergy relationship in people.
“It’s likely that compared to our ancestors, we’re eating unbelievable amounts of fat and sugar, and just not enough fibre,” says co-senior author Charles Mackay. “And these findings may be telling us that we need that high-fibre intake, not just to prevent food allergy, but possibly other inflammatory conditions as well.”