Abstract
An adaptive plasticity of the insulin-secreting pancreatic beta cells, located in the islets of Langerhans, is essential for maintaining proper blood glucose homeostasis under various functional demands. Understanding the molecular mechanisms underlying the regulation of beta cell mass and function is critically dependent on an in vivo monitoring system that can continuously report on the functional status of the islets. Because direct inspection of these islets is obstructed due to the fact that they are deeply embedded and scattered within the pancreas, we propose the use of “reporter islets” transplanted into the anterior chamber of the eye, serving as optically accessible indicators of islet plasticity in the pancreas and as a tool to individually assess effectiveness of specific treatment regimens.
The islets of Langerhans constitute the endocrine part of the pancreas and are responsible for maintenance of blood glucose homeostasis. They are deeply embedded in the exocrine pancreas, limiting their accessibility for functional studies. Understanding regulation of function and survival and assessing the clinical outcomes of individual treatment strategies for diabetes requires a monitoring system that continuously reports on the endocrine pancreas. We describe the application of a natural body window that successfully reports on the properties of in situ pancreatic islets. As proof of principle, we transplanted “reporter islets” into the anterior chamber of the eye of leptin-deficient mice. These islets displayed obesity-induced growth and vascularization patterns that were reversed by leptin treatment. Hence, reporter islets serve as optically accessible indicators of islet function in the pancreas, and also reflect the efficacy of specific treatment regimens aimed at regulating islet plasticity in vivo.
