Sericin in the Isolating Solution Improves the Yield of Islets Isolated from the Pancreas

Approximately half of the transplantable pancreatic islet tissue is lost during isolation, including the digestion and purification steps. Modifying the isolation method could increase the yield. This would enable the one donor-one recipient concept and improve the therapeutic effects of islet transplantation. This study aims to improve islet transplantation by increasing the yield of islets from the pancreas, both the number of islets and their size. Therefore, we used a sericin-containing isolating solution. Rat pancreatic islets were isolated by collagenase digestion and hand picking. We refer to islets isolated with or without sericin in the isolation solution as the sericin and control group, respectively. Volume yield, endocrine function, and islet morphology were compared between the groups. Histological distribution of sericin was evaluated by immunofluorescence staining to examine its mechanism of action in pancreatic islets. The pancreatic islet yield in the sericin group was significantly higher than that in the control group. The endocrine function of islets in the sericin group was comparable to that of islets isolated by conventional methods. Sericin adhered to the surface of isolated pancreatic islets and colocalized with E-cadherin, a cell membrane protein, which might explain the cytoprotective effects of sericin. The islet morphology tended to be better preserved in the sericin group. Sericin could prevent cytoarchitectural damage during the isolation and purification process, resulting in increased pancreatic islet yield. This suggests that sericin could contribute to islet therapy by enhancing the stability of islets.