Mesenchymal Stem Cells: A Potential Border Patrol for Transplanted Islets?

Type 1 diabetes is a disorder caused by the autoimmune-mediated destruction of insulin-producing β-cells in the pancreas (1). Many promising intervention trials are currently underway or in development to prevent β-cell loss in patients with recent-onset type 1 diabetes and in individuals at increased risk for type 1 diabetes due to the presence of autoantibodies or elevated genetic risk (2). Despite this hope for future interventions, islet transplantation remains the only therapeutic option currently available for individuals with established type 1 diabetes when insulin therapy fails to maintain adequate metabolic control (3). Islet allograft transplantation has demonstrated great success in terms of restoring normoglycemia (4). Unfortunately, the long-term efficacy following transplantation has been limited due to chronic graft rejection (5). Thus, an optimal approach would involve an islet transplantation protocol that would prevent graft rejection without the need for potentially dangerous long-term and nonspecific immune suppression.

Mesenchymal stem cells (MSCs) have been proposed to be one possible means to enhance current islet transplantation protocols (6). MSCs represent a population of nonhematopoetic precursor cells that have generated marked interest and attention for their capacity to elicit tissue regeneration (7–9). For the treatment of type 1 diabetes, the therapeutic potential of MSCs is potentially twofold. First, these cells …