Type 1 diabetes is caused when the body’s own immune system attacks the beta cells that produce insulin, and cells can be destroyed over a number of years before symptoms appear. A team of researchers at the Beckman Research Institute of City of Hope in the US have developed a PCR technique that could be used to spot the DNA changes that occur before the rise in blood glucose associated with type 1 diabetes. The research was published in PLoS One.
The researchers looked at DNA methylation patterns in the DNA coding for insulin in diabetic mice and humans. They focused on the insulin promoter, intron 1, exon 2, and intron 2, and found tissue-specific methylation in the insulin promoter, but not in the other regions, which could be used to distinguish beta cell DNA from DNA of other tissues.
The team created a quantitative methylation-specific PCR (qMSP) assay based on the insulin promoter methylation patterns and used this to spot the beta cell DNA that is released into the circulation by damaged cells, either during the development of diabetes or after islet cell transplantation therapy.
Using the assay, the researchers found that in a diabetes mouse model, beta cell death started at the same time as immune cell infiltration, six weeks before blood sugar levels rose.
According to the IDF Diabetes Atlas, 382 million people worldwide have diabetes, which includes type 1, type 2 and gestational diabetes. While type 1 diabetes is less common (5-10%), the numbers are growing at around 3-4% a year in children under 14. Being able to detect the destruction of the beta cells at an early stage could allow people at risk to be monitored more closely and treated at an earlier stage, perhaps even slowing or stopping the damage before the majority of the beta cells are destroyed. It could also be used to track the success or failure of islet cell transplantation therapy.
While xxpress PCR technology was not used in this research, its speed and reproducibility could make it ideal for quick turnaround research.