Finding in type 1 diabetes overturns idea of zero insulin
Beta cells hope for type 1 diabetes
Type 1 diabetes was previously thought to render the pancreas completely unable to produce insulin, the hormone responsible for controlling sugar entry into cells and subsequent blood levels.
The truth, researchers have now discovered, is that very small amounts of insulin are produced in "most" patients, and that levels in the blood even respond to food intake.
The early-onset form of diabetes was thought to kill off all the specialized insulin-secreting beta cells in the pancreas within a few years of developing the condition.
Or, as the study authors put it: "Type 1 diabetes is defined as a disease of progressive autoimmune destruction of beta cells, leading to absolute insulin deficiency."
But their new finding, published in Diabetologia, the journal of the European Association for the Study of Diabetes, shows that some beta cells are either resisting the immune attack that causes people with type 1 diabetes to lose these specialized cells, or they are regenerating themselves.
The development has been enabled by new technology that can measure very small concentrations of insulin in the blood, and the revelation that not all beta cells are killed raises the prospect of treatments that halt or reverse the autoimmune damage in type 1 diabetes.
Until such options are developed, people with type 1 diabetes, who are usually diagnosed in their teens, must rely on daily injections of insulin to keep their blood sugars under control.
The new research was led by the UK's University of Exeter Medical School and funded by the charity Diabetes UK.It found that around three-quarters of patients with the condition possess a small number of beta cells that are not only producing insulin, but also doing so in response to food, "a sign that the cells are healthy and active."
The authors conclude: "This implies that beta cells are either escaping immune attack or undergoing regeneration."The scientists found that 73% of the volunteers (54 out of 74) in the study produced low levels of insulin, regardless of the length of time since their diagnosis.
New technology detects tiny concentrations
The response of the insulin production to a meal proved that the low-level production was coming from working beta cells, the researchers say. The levels of insulin were so low that without this response to food, the effect could have been ascribed to "analytical noise."
Insulin levels were detected in the study by testing for a blood marker of the hormone called C-peptide.Scientists were previously able to measure levels of this substance only at blood concentrations above 30 pmol/l - whereas the new "ultrasensitive assays" are able to detect levels ten times smaller, down to 3.3 pmol/l.
"The impact of using a modern assay with a lower limit of
