Type 1 diabetes study examines babies' intestinal insects

Scientists have explored how bacteria found in the belly of babies and toddlers could contribute to the development of type 1 diabetes.

In a new study, researchers have identified developing populations of intestinal bugs in young children who have been diagnosed with the disease, which affects an estimated 10,000 to 20,000 New Zealanders.

Children with type 1 diabetes have certain types of genes, but not all carriers of the gene develop the disease.

Scientists are investigating whether the development of the intestinal microbiome from birth to childhood could play a protective, predisposing or even triggering role, potentially offering some kind of microbial "safety blanket".

The latest findings come from a compartmental study called Teddy (The Environmental Determinants of Diabetes in Youth), in which researchers collected monthly stool samples, as well as blood samples and registers of the same. diet, health and lifestyle, to generate the richest data set of this type. nowadays.

The children were very far away and lived in Finland, Sweden, Germany and three US states – Washington, Colorado and Georgia – where the Teddy's six collaborating research centers are based.

The new study, one of Teddy's two analyzes, has just been published in the scientific journal Natureused sequencing of bacterial genes to track the intestinal microbiome of Caucasian 1 majority children with type 1 diabetes, aged 3 months to diagnosis – typically 2 to 5 years – and compared with healthy, non-diabetic children.

A third group of children had a pre-diagnosis stage called islet autoimmunity or IA.

The analysis of nearly 11,000 stool samples from 783 children revealed how the variety and mix of intestinal bugs change and develop during infancy.

The researchers found pronounced individual differences – suggesting that unique populations of intestinal bugs evolve from an early age – but also subtle group differences.

Compared to IA children, the healthy cohort had more Lactobacillus rhamnosus, common in fermented dairy products such as yogurt, and linked to better intestinal digestion.

They also harbored more bacterial genes that fuel short chain fatty acid production compared to children with type 1 and type 1 diabetes.

Short-chain fatty acids are beneficial for intestinal health and immune function and are produced solely by intestinal microbes.

"Earlier modest studies have identified changes in the gut microbiome before the onset of type 1 diabetes, suggesting that the intestinal microbiome might be a predisposing factor, even a trigger," said Dr. Tommi Vatanen , lead author of the study.

Vatanen led the study while based at the Broad Institute of MIT and Harvard, and has since joined the Liggins Institute at the University of Auckland as a researcher.

Previous studies at Teddy have also suggested that probiotics may have a protective effect against type 1 diabetes in children with the highest genetic risk.

In the Nordic countries, probiotics are sometimes recommended for infants and young children, and many parents give their baby vitamin D drops and probiotics with breast milk.

"We can not say for sure that probiotics are still protective," said Vatanen.

"First, we need to conduct controlled clinical trials with, for example, carefully selected pro and / or pre-biotic supplements.

"It could also be possible to protect children from type 1 diabetes by radically altering their intestinal microbiome through a transfer of intestinal bacteria – another exciting research direction."

The researchers also found geographical differences in children's intestinal insects.

For example, Finnish children had on average more Bifidobacterium breve, sometimes used as a probiotic and belonging to a group of bacteria known to be beneficial to the health of the intestine.

"This could be due to differences in the mother's intestinal microbiome, that she is transferring to the baby, or to differences in breast milk and early feeding in general."

Vatanen is also one of the authors of a second study of Teddy published in the same issue of Nature, which analyzed 12,500 stool samples from 903 children and identified three distinct phases of gut microbiome development, influenced by breastfeeding and other environmental factors.