There is no solid scientific evidence that alterations in the gut microbiota cause autism, according to an opinion piece published in the scientific journal Neuron. The research supporting this hypothesis—observational studies and clinical trials in humans, as well as mouse models—has both conceptual and methodological shortcomings, the authors write.
Researchers have modified a bacterium to colonise the gut microbiota and treat kidney stones. They genetically engineered Phocaeicola vulgatus to make it able to break down oxalate molecules, a cause of recurrent kidney stones, and consume a specific nutrient called porphyrin. In mice and in preclinical trials in healthy people, this reduces oxalate levels, the authors report in the journal Science.
An international study has warned of the potential risks of widespread use of faecal microbiota transplantation without taking into account the region of the intestine where the transferred microbes arrive. The experiment, conducted on mice and human tissue samples, showed that the microbes from the transplant—mostly anaerobic microbes from the colon—colonised the small intestine, persisted there for months and modified that new environment, causing changes in the host's metabolism. According to the authors, whose study is published in the journal Cell, this may have long-lasting and unforeseen consequences, as well as imbalances in the intestinal ecosystem of patients.
A team from France has studied the intestinal microbiota of elite athletes with high aerobic capacity (footballers and cyclists). The data indicates that they have less bacterial diversity and that the transplantation of faeces from athletes to mice improves metabolic parameters such as insulin sensitivity and glycogen deposits in the muscles. The results are published in the journal Cell Reports.
A team from the University of Iowa (USA) has found a relationship between specific species of microbiota bacteria and the severity of multiple sclerosis. Specifically, a lower ratio between the quantities of Bifidobacterium and Akkermansia was related to the disease and to a worse course of the disease, both in mice and in two cohorts of patients and people without the disease. According to the authors, who publish the results in the journal PNAS, the finding could be used to improve the diagnosis and treatment of multiple sclerosis.
A synthetic microbiome therapy, tested on mice, protects against the severe symptoms of a difficult-to-treat and potentially fatal intestinal infection in humans: Clostridioides difficile. Although inspired by the idea of human faecal transplants, the new approach does not require faecal matter. Instead, it uses fewer, but more precise, bacterial strains. The study is published in the journal Cell Host & Microbe.
‘Bacterial signatures’ from genital areas could serve as a forensic tool to identify perpetrators of sexual assault, even if there is no trace of sperm, according to a study published in the journal iScience, by the Cell group. After sequencing the DNA of bacteria from genital samples from 12 stable couples, the authors show that a transfer of bacterial species occurs during intercourse, allowing the identification of each person’s own genital microbiome or ‘sexome’.
Research in mice shows that the gut microbiota of pregnant mice influences the development of stem cells in their offspring. Changes in the bacterium Akkermansia muciniphila in the maternal microbiota alter the proliferation of intestinal and neural cells in the offspring, according to the study published in Cell Stem Cell.
An analysis of the gut microbiota of children growing up on farms or with pets shows that early establishment of anaerobic commensal bacteria is associated with lower rates of allergy later in life. The study, which used data from 65 children aged between three days and 18 months, is published in the journal PLOS ONE.
Many diseases related to bacteria, such as inflammatory bowel disease or colorectal cancer, are associated with an overgrowth of gut bacteria considered 'bad'. However, a study published in the journal Cell suggests that changes in microbial load, rather than the disease itself, could be the driving factor behind the presence of these harmful species associated with pathologies.