People with diabetes mellitus have substantially reduced numbers of pancreatic β-cells compared with healthy individuals. Now, a study in Science Translational Medicine demonstrates the efficacy of a dual tyrosine-regulated kinase 1A (DYRK1A) inhibitor treatment combined with a glucagon-like peptide 1 (GLP1) receptor agonist for increasing human β-cell mass in vivo.

The researchers transplanted human pancreatic islets under the kidney capsule of immunodeficient (Rag1−/−) mice. These mice were treated for up to 3 months with either vehicle control, harmine, exendin 4 (a GLP1 receptor agonist) or a combination of harmine and exendin 4 (H&E). “We implemented a tissue clarification technique plus a light sheet microscopy approach called iDISCO+ to visualize in 3D the human islets transplanted under the kidney capsule,” says Garcia-Ocaña.