Ever heard of the eyes being the windows to the soul? A recent technique to study an otherwise inaccessible structure of an organ seems to have added weight to the proverb. Scientists at the Karolinska Institutet in Sweden have devised a technique to study part of the pancreas, without the need for invasive surgery, via the eye, with the procedure hailed as a significant step forward in diabetes research.
The structure in question is the Islets of Langerhans, an endocrine (or hormone-producing) structure which is situated deep within the tissue of the pancreas and makes up between one and two percent of its mass. Here, insulin is produced from beta-cells, that make up around 70 percent of all the cells in the Islets. The role of insulin aims to regulate blood sugar levels following a meal, either causing the sugar to be taken up by muscle tissue or deposited as fat in adipose tissue.
The Islets of Langerhans are a dynamic region, capable of adjusting the amount of insulin produced depending on bodily requirements for the hormone: a large meal, for example, may require higher blood insulin levels, which the beta-cells might produce accordingly. Of course, individual variation may have an impact on the amount produced.
When excessive consumption of food occurs, over a long period of time, the beta-cells respond by increasing the insulin available in the blood. However, the tissues which normally respond to the hormone, the aforementioned muscle cells and fat cells make up adipose tissue, become resistant, leading to hyperglycaemia, a condition where individuals have high blood sugar levels.
In order to compensate, beta-cells further increase insulin production, which can then lead to hyperinsulinemia. As a result, several metabolic conditions may develop, including hypertension, as well as coronary heart conditions and type-2 diabetes. The inaccessibility of the tissue has meant it has previously been challenging for scientists to study the Islets of Langerhans, however new findings published in the journal PNAS have opened the eyes to potential new techniques in the study of diabetes and other metabolic conditions.
By transferring beta-cells to the anterior chamber of the eye (between the innermost layer of the cornea and the iris, the layer responsible for causing eye color), the cells are now “optically accessible”, according to Per-Olof Berggren, professor of experimental endocrinology at Karolinska Institutet’s Department of Molecular Medicine and Surgery.
These ‘reporter cells’ are structurally and functionally identical to the ones found within the organ, and now allow scientists to examine the activity of the pancreas without the need to enter the body during invasive surgery. This visualization of the pancreas means the organ may be studied over a period of several months in order to assess the structural and functional changes during various incidents of health and wellbeing, with the ‘reporter cells’ acting as the indicators. Drugs may now be individually altered depending on the nature of the condition.
Professor Per-Olof Berggren and his team demonstrated this principle using leptin-deficient mice. Leptin is a hormone responsible for a suite of functions relating to energy intake and use, including appetite. A deficiency in this hormone results in uncontrolled food intake, which in the long run might lead to type-2 diabetes, amongst other conditions.The beta-cells in the anterior eye chamber of these mice showed the expected weight-induced growth and vascularization as a result of excessive food consumption.
What Professor Per-Olof Berggren was able to do was reverse this condition via leptin therapy, reducing the appetite in the animals and thus proving that the cells present in the eye act as health indicators of the pancreas, as well as the effective nature of using specific treatment in controlling conditions such as leptin-deficiency.
This ‘reporter cell’ system might help categorize new drugs that regulate beta-cell hormone production. This novel and revolutionary technique may be used in humans in the near future in order to create individually unique treatments as well as monitor the effects of medication on an individual, while diagnosing conditions in the pancreatic tissue and choosing the appropriate course of action.
What kind of impact might this procedure have on the treatment of weight-related conditions?