Coculture With Ischemia/Reperfusion-Preconditioned Hepatocytes Improves Islet Function and Survival

Area of Science:

• Cell Biology
• Transplantation Immunology
• Regenerative Medicine

Background:

• Clinical islet transplantation faces challenges including hepatic ischemia and poor neovascularization, hindering islet graft survival and function.
• Hepatocytes possess inherent protective mechanisms against ischemic conditions.
• Ischemia/reperfusion preconditioning (IRP) is a potential strategy to enhance cellular resilience.

Purpose of the Study:

• To investigate the hypothesis that IRP of hepatocytes can confer protective benefits to cocultured islet cells.
• To evaluate the impact of IRP-treated hepatocytes on islet cell survival, insulin secretion, and gene expression.
• To determine the optimal IRP protocol for hepatocyte preconditioning in a coculture system.

Main Methods:

• Primary islets were cocultured with primary hepatocytes.
• Hepatocytes underwent IRP via single or tandem hypoxic exposures (15 or 30 minutes).
• Assessed gene expression (IGF-1, HGF, TGF-α, TGF-β1), growth factor secretion, insulin secretion (glucose challenge), cell viability (MTT assay), and apoptosis (TUNEL stain).

Main Results:

• IRP significantly increased IGF-1, HGF, TGF-α, and TGF-β1 gene expression in hepatocytes.
• IRP hepatocytes secreted increased levels of HGF and IGF-1.
• Coculture with IRP hepatocytes enhanced islet insulin secretion, Bcl-2 and Reg-1α expression, and significantly improved islet viability compared to non-preconditioned controls.

Conclusions:

• IRP of hepatocytes induces protective factors that benefit cocultured islet cells.
• Coculture with IRP hepatocytes improves islet survival and enhances insulin secretory function.
• This approach holds potential for improving outcomes in clinical islet transplantation by mitigating ischemic injury.