This week in animal research: w/e 22 August
Mice given repeated low doses of antibiotics during early life are extremely prone to obesity, according to a new study that examined the role of gut bacteria in metabolism. Researchers found that the antibiotic doses disrupted the development of the mouse microbiome, effects that disappeared within a couple of weeks of the last antibiotic dose. However when fed a high fat diet the treated mice started to gain weight much more rapidly than untreated controls, with females being particularly susceptible. When gut microbes were transferred from treated mice into mice who had previously been kept germ-free, the recipients immediately began to gain weight when put on a high-fat diet.
Marmoset monkeys may be the key to developing new treatments for Middle Eastern Respiratory Syndrome (MERS). Less popular than Ebola at the moment, but still the subject of a focussed international research effort, MERS causes severe pneumonia in humans. So far over 800 cases have been reported, with over 200 deaths. The hunt for a suitable animal model of the disease has been largely unsuccessful as many animals do not get as severe symptoms as humans. However, new research published today show that marmosets are affected by the virus in very similar ways to humans. The development of the marmoset model could have a “major impact” in the search for drugs and vaccines against MERS, the scientists say.
Hearts from genetically altered piglets have been successfully transplanted in the baboons, in a US study examining the likelihood of donor organ rejection. The donor hearts were placed in the monkeys’ abdomens and survived there for more than a year, twice as long as previously reported. The pigs had a number of genes that cause adverse immune reactions in organ recipients “knocked out” and replaced with human genes to increase their compatibility. The study also used more targeted immunosuppressant drugs, which are less toxic than general immunosuppresants.
Using Botox to kill the nerves surrounding growing stomach cancers in mice appeared to halt the growth of the tumours and make them more vulnerable to chemotherapy. The study examined the role of the vagus nerve, which runs from the brain to the digestive system, in stomach cancer. Both cutting the nerve or disrupting its activity using Botox made the stomach tumours more susceptible to chemotherapy. One of the scientists, Dr Timothy Wang, commented that, "At least in early phase, if you [disrupt the nerve] the tumour becomes much more responsive to chemotherapy, so we don't see this as a single cure, but making current and future treatments more effective."
A treatment administered days after infection has saved moneys from Marburg virus, a deadly relative to Ebola. Marburg virus also causes a lethal haemorrhagic fever, and an outbreak in Angola in 2004-05 killed more than 90% of infected people. TKM-Marburg, developed by a Canadian pharmaceutical company, was used to treat the disease in 16 rhesus macaques divided into four groups that each received the treatment at a different time after infection. All the monkeys given the treatment survived, whereas four untreated animals died. Study author Thomas Geisbert, a microbiologist at the University of Texas Medical Branch in Galveston, says that this is the first time that a single drug has been shown to save animals from Marburg when it is administered days after the virus enters their bodies.
Urban-dwelling spiders are getting bigger thanks to warmer temperatures and more abundant food sources. However the researchers claim that this is a beneficial change, as the spiders are important for keeping the insect population in check, and they are a valuable food source for birds. UK arachnophobics shouldn’t panic too soon however, as this research was conducted on the other side of the world on a species of Australian orb-weaver spider Nephilia plumipes, found living in Sydney.