Syngeneic implantation of mouse hepatic progenitor cell-derived three-dimensional liver tissue with dense collagen fibrils

BACKGROUND Liver transplantation is a therapy for irreversible liver failure;however,at present,donor organs are in short supply.Cell transplantation therapy for liver failure is still at the developmental stage and is critically limited by a shortage of human primary hepatocytes.AIM To investigate the possibility that hepatic progenitor cells(HPCs)prepared from the portal branch-ligated hepatic lobe may be used in regenerative medicine,we attempted to enable the implantation of extracellular matrices containing organoids consisting of HPC-derived hepatocytes and non-parenchymal cells.METHODS In vitro liver organoid tissue has been generated by accumulating collagen fibrils,fibroblasts,and HPCs on a mesh of polylactic acid fabric using a bioreactor;this was subsequently implanted into syngeneic wild-type mice.RESULTS The in vitro liver organoid tissues generated transplantable tissues in the condensed collagen fibril matrix and were obtained from the mouse through partial hepatectomy.CONCLUSION Liver organoid tissue was produced from expanded HPCs using an originally designed bioreactor system.This tissue was comparable to liver lobules,and with fibroblasts embedded in the network collagen fibrils of this artificial tissue,it is useful for reconstructing the hepatic interstitial structure.

Different micro/nano-scale patterns of surface materials influence osteoclastogenesis and actin structure

The surface topography of a material can influence osteoclast activity.However,the surface structural factors that promote osteoclast activity have not yet been investigated in detail.Therefore,we investigated osteoclastogenesis by testing various defined patterns with different dimensions and shapes.The systematic patterns,made of a cyclo-olefin polymer,were prepared at a micron-,submicron-,and nano-scale with a groove,hole,or pillar shape with a 1:1 pitch ratio.RAW264.7 cells were cultured on these patterns in the presence of the receptor activator of NF-κB ligand(RANKL).Osteoclast formation was induced in the order:pillar>groove≥hole.The two-dimensional factors also indicated that submicron-sized patterns strongly induced osteoclast formation.The optimal pillar dimension for osteoclast formation was 500 nm in diameter and 2μm in height.Furthermore,we observed two types of characteristic actin structure,i.e.,belt-like structures with small hollow circles and isolated ring-like structures,which formed on or around the pillars depending on size and height.Furthermore,resorption pits were observed mainly on the top of calcium phosphate-coated pillars.Thus,osteoclasts prefer convex shapes,such as pillars for differentiation and resorption.Our results indicate that osteoclastogenesis can be controlled by designing surfaces with specific morphologies.

Erratum to: Different micro/nano-scale patterns of surface materials influence osteoclastogenesis and actin structure

The article“Different micro/nano-scale patterns of surface materials influence osteoclastogenesis and actin structure”,written by Tsukasa Akasaka,Miho Tamai,Yoshitaka Yoshimura,Natsumi Ushijima,Shinichiro Numamoto,Atsuro Yokoyama,Hirofumi Miyaji,Ryo Takata,Shuichi Yamagata,Yoshiaki Sato,Ko Nakanishi,and Yasuhiro Yoshida,was originally published electronically on the publisher’s internet portal on January 17,2022 without open access.