According to a study published in the scientific journal Diabetes, Swedish researchers from the Karolinska Institutet managed to prevent onset of Type 1 diabetes in mice genetically susceptible to the disease by injecting them with specifically prepared cells that prevented insulin-producing pancreatic beta cells from continuously being destroyed before clinical diabetes occurs.

In Type 1 diabetes, the body’s immune system attacks and kills insulin-producing beta cells, leading to an insulin deficiency that needs to be rectified by injecting insulin. Although scientists do not know the initial causes of this autoimmune destruction, they have discovered that macrophages, a specific type of immune cells, play an active role in killing pancreatic beta cells in patients with Type 1 diabetes. However, according to previous studies, macrophages can also protect against inflammation-mediated tissue damage. Immune cells use cytokines (signal molecules) for signaling each other with instructions on how the cells should act.

The researchers set out to determine which cytokines are necessary to instruct macrophages to become protective cells.

For their study, the team used ‘NOD mice’, i.e. mice that are genetically susceptible to spontaneously develop Type 1 diabetes between the ages of 12 to 30 weeks to grow macrophages from the mice’ bone marrow progenitors. They then stimulated the mature macrophages with the defined combination of cytokines. When the NOD mice reached the age of 16 weeks, the researchers divided them into three separate groups; mice treated with cytokine-stimulated macrophages treatment, mice treated with untreated macrophages and untreated animals.

The animals were monitored for a duration of 12 weeks after treatment, and the team was able to visualize the extent of the beta cells’ immune-mediated attack in each treatment group by using a specific three-dimensional imaging technique that was developed at Umeå University, Sweden.

The results revealed that at the end of the follow-up period, only 25% of mice in the cytokine-treated macrophages group had developed Type 1 diabetes compared with 83% of the animals in the control groups, which developed the disease.

Dr. Harris concludes: “The cell therapy was initiated just 2 weeks before mice developed clinical diabetes. At this stage few insulin-producing beta cells remain in the pancreas, yet we were able to protect these so that the mice never developed diabetes. Such a successful late-stage intervention has never previously been reported and is a significant result of our study. At the time of their clinical Type 1 diabetes diagnosis, most human individuals have already lost most of their insulin-producing beta cells.”

Written By Petra Rattue