Different intestinal insects in children with type 1 diabetes

The researchers are about to understand the role that intestinal insects can play in the development of type 1 diabetes.
A major international study has identified developing populations of intestinal bugs in infants and toddlers, who were later diagnosed with this 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 people with the condition 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 a kind of microbial "safety blanket".

The latest findings come from an umbrella study called TEDDY (Environmental Determinants of Diabetes in Youth), in which researchers collected monthly stool samples, along with blood samples and diet registers, from health and lifestyle, to generate the richest data set of this type. nowadays. The children were widely dispersed and lived in Finland, Sweden, Germany and three US states – Washington, Colorado and Georgia – where the six collaborating research centers of TEDDY are based.

The new study, one of two recently published TEDDY analyzes in Nature, used sequencing of bacterial genes to track the intestinal microbiome of children, mostly Caucasian, with type 1 diabetes from three months until diagnosis, usually between two and five years. – and compared to that of healthy and 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.

Lead author, Dr. Tommi Vatanen, said: "More modest earlier studies have identified changes in the intestinal microbiome prior to the onset of type 1 diabetes, suggesting that the intestinal microbiome might be a factor predisposing or even a triggering factor. "

Dr. Vatanen conducted the study at MIT Broad Institute and Harvard. Since then, he has joined the Liggins Institute of the University of Auckland, New Zealand, as a researcher.

Previous studies in 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.

"However, we can not say for sure that probiotics are protective," says Dr. 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 bugs – 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 family of bacteria known to be beneficial to the health of the intestine.

Dr. Vatanen: "This could be due to differences in the intestinal microbiome of the mothers, which it transfers to the baby, or to differences in breast milk and early feeding in the beginning."

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