Endoscopic submucosal dissection (ESD) permits en bloc removal of superficial oesophageal squamous cell carcinoma (ESCC). However, post-procedure stricture is common after ESD for widespread tumours, and multiple endoscopic balloon dilation (EBD) procedures are required. We aimed to evaluate the safety and effectiveness of endoscopic transplantation of tissue-engineered autologous oral mucosal epithelial cell sheets that had been transported by air over a distance of 1200 km in controlling postprocedural oesophageal stricture. Ten patients who underwent complete circular or semicircular ESD for ESCC were transplanted with cell sheets. The safety of the entire process including cell sheet preparation, transport, ESD and cell sheet transplantation was assessed. The incidence of oesophageal stricture, number of EBD sessions, and time until epithelialization were investigated. Each ESD was successfully performed, with subsequent cell sheet engrafting carried out safely. Following cell sheet transplantation, the luminal stenosis rate was 40%, while the median number of EBD sessions was 0. The median post-ESD ulcer healing period was rather short at 36 days. There were no significant complications at any stage of the process. Cell sheet transplantation and preparation at distant sites and transportation by air could be a safe and promising regenerative medicine technology.

A culture system with spherical multicellular aggregates (spheroids), which are formed by the rearrangement and compaction of cell aggregates, is reported to be more useful than the traditional monolayer culture system for the culture of primary hepatocytes. By performing real-time polymerase chain reaction, we analyzed the expression of genes encoding key molecules involved in liver-specific functions, namely, cell adhesion molecules (integrin 3, cadherin 1 and connexin 32), transcription factors (hepatic nuclear factor 4α and CCAAT/enhancer-binding protein β), protein and metabolic enzymes (albumin, glucose-6-phosphatase, tryptophan 2,3-dioxygenase, arginase 1 and cytochrome P450 7A1) and transporters (organic anion transporting peptide 1, multidrug resistance-associated protein 2 and bile salt export pump), in spheroids derived from rat hepatocytes. Further, we compared these expression levels with those in a hepatocyte monolayer and in liver tissue. Only the gene encoding glucose-6-phosphatase (required for sugar metabolism) was expressed at a similar level in both the monolayer culture and liver tissue for 10 days of culture; the expression of all the other genes in the monolayer culture either rapidly decreased or completely disappeared as the culture duration increased. Although the expression levels of all the genes in the spheroids tended to decrease gradually with culture time, they were consistently higher than those in the monolayer culture for at least 10 days of culture. These results suggest that hepatocyte spheroids acquire intercellular organization and largely maintain many intercellular metabolic functions. Thus, the hepatocyte spheroid culture system seems to be promising for various in vitro cell-based assays.