Integration of transplanted chemically induced liver progenitor cells into recipient bile ducts in a rat bile duct transection model

BACKGROUND: Chemically induced liver progenitor cells (CLiPs) generated from mature hepatocytes are bipotent and represent a promising source for biliary repair. However, their therapeutic potential in cholangiopathy models remains unclear. In this study, we investigated rat CLiPs using a rat bile duct transection (BDT) model. METHODS: Rat CLiPs were induced using the Y-27632/A-83-01/CHIR99021 regimen, resulting in loss of the hepatocyte marker ALB and gain of the progenitor markers CD90 and EpCAM. GFP-labeled CLiPs (1 × 10^7) were transplanted into Sprague-Dawley rats following BDT via portal vein infusion. On postoperative days (POD) 3 and 7, engraftment, proliferation, differentiation, and injury indices were assessed using immunofluorescence, quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and serum biochemistry. RESULTS: CLiPs engrafted and survived until POD 7 after portal vein infusion, and proliferative activity was observed by Ki-67 staining. Immunofluorescence revealed GFP + /ALB+ hepatocyte-like cells and GFP + /CK7 + cholangiocyte-like cells integrating near native ducts, indicating bipotential differentiation. qRT-PCR showed that BDT-induced expression of progenitor/ductular markers (Sox9, Epcam, Krt7, and Krt19) was attenuated in CLiP-treated groups compared to untreated BDT rats, although levels remained above those in sham rats. Serum AST, ALT, and ALP levels tended to decrease, and albumin levels increased after CLiP transplantation. CONCLUSIONS: CLiPs survived and acquired hepatocyte-like and cholangiocyte-like phenotypes during the early phase after portal vein transplantation in a rat BDT model. These findings support the feasibility of CLiP-based hepatobiliary regenerative therapy, although longer-term and functional studies are required to confirm durable biliary repair.