UK researchers have found convincing signs that suggest that type 1 diabetes itself comprises two distinct subtypes: T1DE 1 and T1DE 2.
In the new study, published in the scientific journal Diabetology, the scientists analyzed approximately 130 pancreas samples from children and young people recently diagnosed with type 1 diabetes.
According to the website Science Alert, the results showed “two different patterns” in relation to the amount of proinsulin: the precursor to the insulin that is produced in the pancreas.
In children under the age of seven at the time of diagnosis, proinsulin was not processed properly and was released from pancreatic islets (also known as islets of Langerhans) – a sign that the precursor is not being transformed into enough insulin that the body needs.
On the contrary, in samples taken from patients 13 years of age or older at the time of diagnosis, proinsulin and insulin were not located in this way, suggesting a more normalized production of the hormone.
In addition, in both endotypes, the team also observed the autoimmune destruction of insulin-producing cells in the pancreatic islets, but at different rates – as in the results of previous studies, in children under seven years old this destructive process occurred more aggressive way.
"Our results strongly suggest that type 1 diabetes exists as distinct conditions that segregate according to age at diagnosis and are histologically distinguishable," explain the researchers in their study.
"We propose that they can represent endotypes of the disease and we suggest that they be defined as endotype 1 of type 1 diabetes (T1DE1) and endotype 2 of type 1 diabetes (T1DE2)".
T1DE1, indicative of the interruption of insulin processing, is found in children aged seven years or younger when diagnosed, while T1DE2 is the endotype found in children aged 13 and over. Scientists say that children diagnosed between the ages of seven and 13 may have either endotype.
"We do not intend to suggest that a simple dichotomy will be sufficient to explain all the heterogeneity observed in people who develop type 1 diabetes. Instead, it is likely that additional endotypes will be defined as other variables are considered," write the authors.