Pancreatic injury induces β-cell regeneration in axolotl

Background Diabetes is a condition characterized by a loss of pancreatic β-cell function, which results in the dysregulation of insulin homeostasis. Using a partial pancreatectomy model in axolotl, we aimed to observe the pancreatic response to injury. Results Here we show a comprehensive histological characterization of pancreatic islets in axolotl. Following pancreatic injury, no apparent blastema-like structure was observed. We found a significant, organ-wide increase in cellular proliferation post-resection in the pancreas compared to sham-operated controls. This proliferative response was most robust at the site of injury. Further, an increase in nuclear density was observed, suggesting compensatory congestion as a mechanism of regeneration. We found that β-cells actively contributed to the increased rates of proliferation upon injury. β-Cell proliferation manifested in increased β-cell mass in injured tissue at 2 weeks post-injury. At 4 weeks post-injury, we found organ-wide proliferation to be extinguished while proliferation at the injury site persisted, corresponding to pancreatic tissue recovery. Similarly, total β-cell mass was comparable to sham after 4 weeks. Conclusions Our findings suggest a non-blastema-mediated regeneration process takes place in the pancreas, by which pancreatic resection induces whole-organ β-cell proliferation without the formation of a blastemal structure. This process is analogous to other models of compensatory congestion in axolotl.