Keeping an Eye on Diabetes

When the demand for insulin is high – such as during prolonged periods of excess food consumption or when insulin resistance occurs – the number of β cells increases. This plasticity is essential for normal blood sugar levels to be maintained; diabetes results from its dysfunction.

Assessing the state of β-cells in vivo would provide valuable information on the function of the cells and on disease state of patients with insulin resistance or diabetes. However, it is difficult to assess these cells, given their location: non-invasive imaging techniques like ultrasound or magnetic resonance imaging are inadequate, and biopsies are invasive and give only a snapshot of what’s going on. Now, a new approach has been proposed by Per-Olof Berggren, a Professor of Experimental Endocrinology at Sweden’s Karolinska Institutet and Erwin Ilegems,  researcher at the Rolf Luft Research Centre for Diabetes and Endocrinology, and their colleagues. Their solution is to transplant Islets of Langerhans into the anterior chamber of the eye. The work, for now, is being conducted in mice (1).

“We’ve made the cells optically accessible by grafting a small number of ‘reporter islets’ into the eyes of mice, which allows us to monitor the activity of the pancreas just by looking into the eye,” says Berggren. “We’re now able to really study the insulin-producing β-cells in detail in a way that wasn’t possible before.” “The transplanted islets can be visualized repeatedly over a period of months. During this time, the functional and morphological changes that occur in them that are identical to those occurring in the pancreas,” says Ilegems.

“We’ll be using the system to identify new drug substances that regulate β-cell plasticity and function,” Berggren adds. “In the future we may develop reporter islets in humans in order to find unique, tailored treatment principles, to measure the effects of personal medication, or to diagnose problems with the pancreatic islets.” So don’t be too surprised when you perform ophthalmoscopy in a decade’s time if you see bits of the body that shouldn’t really be there. The principle may also work with other cell types too – so it may be that a whole diagnostic panel of disease-marking cells could await your examination.