A small molecule circulates in the blood of people who are in the early stages of type 1 diabetes and a simple blood test could detect this biological marker years, maybe decades, before symptoms develop.

Micro ribonucleic acids (miRNAs) carry snippets of genetic information across cells, and are regularly released into the blood stream and in diabetes the levels of some of these miRNAs in the circulation changes, and a blood test could detect these variations.

An international team of scientists, led by those at the Imperial College London (UK), have been able to identify a miRNA that is linked to the pancreas. They first used a murine model to establish the techniques and then recruited individuals diagnosed with diabetes who were less than 45 years of age. The subjects studied included 45 with the genetic mutation HNF1α-MODY3, 38 with type 1 diabetes (T1D) and 58 with type 2 diabetes (T2D). There were 51 controls who were normoglycemic individuals aged 30 to 50 years.

RNA was reverse transcribed using a High Capacity cDNA Reverse Transcription kit and miRNA levels were measured using the TaqMan microRNA Assays (Applied Biosystems; Waltham, MA, USA). Quantitative polymerase chain reaction (PCR) was performed by Roche 384 real-time PCR machine and using Light Cycler 480 SYBR Green Master (Roche; Basel Switzerland).

The scientists reported that a particular molecule, called miR-375, is released by the very cells in the pancreas that produce insulin. These cells normally contain lots of miR-375, which helps to control cell growth. In T1D it is released into the bloodstream in large quantities as soon as the cells begin to die. Their results indicate that that plasma miR-375 levels do not discriminate between different forms of T2D, but may be used as an indicator of acute β-cell destruction and autoimmune diabetes.

The authors concluded that their findings are supported by higher miR-375 levels in the circulation of T1D subjects but not mature onset diabetes of the young (MODY) andT2D patients. Together, their data support an essential role for miR-375 in the maintenance of β-cell mass and provide in vivo evidence for release of miRNAs from pancreatic β-cells. The small contribution of β-cells to total plasma miR-375 levels make this miRNA an unlikely biomarker for β-cell function but suggests a utility for the detection of acute β-cell death for autoimmune diabetes. The study was published on May 28, 2015, in the Journal of Molecular Medicine.

Related Links:
Imperial College London 
Applied Biosystems 
Roche