We report a simple method, using p53 suppression and nontransforming L-Myc, to generate human induced pluripotent stem cells (iPSCs) with episomal plasmid vectors. We generated human iPSCs from multiple donors, including two putative human leukocyte antigen (HLA)-homozygous donors who match ∼20% of the Japanese population at major HLA loci; most iPSCs are integrated transgene-free. This method may provide iPSCs suitable for autologous and allologous stem-cell therapy in the future.

SummaryAge-related macular degeneration (AMD) causes severe visual impairment due in part to age-dependent impairment of retinal pigment epithelium (RPE). It has been suggested that autologous human induced pluripotent stem cells (hiPSCs) may represent a useful cell source for the generation of graft RPE. We generated hiPSC-derived RPE (hiPSC-RPE) cell sheets optimized to meet clinical use requirements, including quality, quantity, consistency, and safety. These cell sheets are generated as a monolayer of cells without any artificial scaffolds, express typical RPE markers, form tight junctions that exhibit polarized secretion of growth factors, and show phagocytotic ability and gene-expression patterns similar to those of native RPE. Additionally, upon transplantation, autologous nonhuman primate iPSC-RPE cell sheets showed no immune rejection or tumor formation. These results suggest that autologous hiPSC-RPE cell sheets may serve as a useful form of graft for use in tissue replacement therapy for AMD.

Organoid technology provides a revolutionary paradigm toward therapy but has yet to be applied in humans, mainly because of reproducibility and scalability challenges. Here, we overcome these limitations by evolving a scalable organ bud production platform entirely from human induced pluripotent stem cells (iPSC). By conducting massive "reverse" screen experiments, we identified three progenitor populations that can effectively generate liver buds in a highly reproducible manner: hepatic endoderm, endothelium, and septum mesenchyme. Furthermore, we achieved human scalability by developing an omni-well-array culture platform for mass producing homogeneous and miniaturized liver buds on a clinically relevant large scale (>10). Vascularized and functional liver tissues generated entirely from iPSCs significantly improved subsequent hepatic functionalization potentiated by stage-matched developmental progenitor interactions, enabling functional rescue against acute liver failure via transplantation. Overall, our study provides a stringent manufacturing platform for multicellular organoid supply, thus facilitating clinical and pharmaceutical applications especially for the treatment of liver diseases through multi-industrial collaborations.

The therapeutic efficacy of angiotensin II receptor antagonist, losartan, was studied in patients with nonalcoholic steatohepatitis (NASH). Seven patients with both NASH and hypertension were treated with losartan (50 mg/d) for 48 weeks. Treatment with losartan resulted in a significant decrease in blood markers of hepatic fibrosis, plasma TGF-␤1 and serum ferritin concentration concurrently with an improvement in serum aminotransferase levels. Histological assessment showed improvement of hepatic necroinflammation in five patients, reduction of hepatic fibrosis in four patients, and disappearance of iron deposition in two patients. No side effect of treatment was noted at any time during the study. In conclusion, the present data raise the possibility that an angiotensin II receptor antagonist may be therapeutically efficacious for NASH. (HEPATOLOGY 2004;40:1222-1225 N onalcoholic steatohepatitis (NASH) is a distinct clinical entity characterized by varying degrees of progressive steatosis, lobular inflammation and fibrosis of the liver. 1,2 Although the causes of NASH are not well defined and several therapies including diet, 3 antioxidants, 4 and approaches that improve insulin resistance 5 have been tried, no commonly accepted therapeutic protocol has yet been established. Recent studies have demonstrated a crucial role of angiotensin II in the pathogenesis of hepatic fibrosis, 6 and this peptide has been shown to enhance insulin resistance and tissue iron deposition. 7,8 Administration of an antagonist of angiotensin II type 1 receptor has been shown to decrease hepatic fibrosis in rats. 6 In the present study, the effects of losartan, a selective angiotensin II type I receptor antagonist, were investigated in patients with NASH. Patients and MethodsEight patients (two men and six women), aged 41-65 (median 57) years, with both NASH and hypertension, were entered into this study. All patients consumed less than 40 g of alcohol per week. Four patients were obese (body mass index Ͻ 25), four had diabetes mellitus, four had hyperlipidemia, and one had hyperuricemia. At the time of the study, some of the patients had already been on medication, including benzodiazepines, calcium antagonists or anticoagulants for at least 12 months. These therapeutic regimens were not changed after the start of the study. None of the patients were taking any angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists before the study.Baseline laboratory assessment revealed abnormally high serum transaminase and ␥-glutamyl transpeptidase concentrations in all patients. Five patients showed high serum ferritin concentrations. Homeostasis model assessment (HOMA)-R was abnormally high in all patients. Liver biopsies were performed prior to entry the study, and revealed moderate to severe lobular steatosis, and various degrees of hepatic necroinflammation and fibrosis in all patients. In two patients, iron deposition in hepatocytes was noted (Table 1).

SummaryIn this article, we show that mouse embryonic stem cell- or induced pluripotent stem cell-derived 3D retinal tissue developed a structured outer nuclear layer (ONL) with complete inner and outer segments even in an advanced retinal degeneration model (rd1) that lacked ONL. We also observed host-graft synaptic connections by immunohistochemistry. This study provides a “proof of concept” for retinal sheet transplantation therapy for advanced retinal degenerative diseases.