SummaryDefects in articular cartilage ultimately result in loss of joint function. Repairing cartilage defects requires cell sources. We developed an approach to generate scaffoldless hyaline cartilage from human induced pluripotent stem cells (hiPSCs). We initially generated an hiPSC line that specifically expressed GFP in cartilage when teratoma was formed. We optimized the culture conditions and found BMP2, transforming growth factor β1 (TGF-β1), and GDF5 critical for GFP expression and thus chondrogenic differentiation of the hiPSCs. The subsequent use of scaffoldless suspension culture contributed to purification, producing homogenous cartilaginous particles. Subcutaneous transplantation of the hiPSC-derived particles generated hyaline cartilage that expressed type II collagen, but not type I collagen, in immunodeficiency mice. Transplantation of the particles into joint surface defects in immunodeficiency rats and immunosuppressed mini-pigs indicated that neocartilage survived and had potential for integration into native cartilage. The immunodeficiency mice and rats suffered from neither tumors nor ectopic tissue formation. The hiPSC-derived cartilaginous particles constitute a viable cell source for regenerating cartilage defects.

Gain-of-function mutations in the fibroblast growth factor receptor 3 gene (FGFR3) result in skeletal dysplasias, such as thanatophoric dysplasia and achondroplasia (ACH). The lack of disease models using human cells has hampered the identification of a clinically effective treatment for these diseases. Here we show that statin treatment can rescue patient-specific induced pluripotent stem cell (iPSC) models and a mouse model of FGFR3 skeletal dysplasia. We converted fibroblasts from thanatophoric dysplasia type I (TD1) and ACH patients into iPSCs. The chondrogenic differentiation of TD1 iPSCs and ACH iPSCs resulted in the formation of degraded cartilage. We found that statins could correct the degraded cartilage in both chondrogenically differentiated TD1 and ACH iPSCs. Treatment of ACH model mice with statin led to a significant recovery of bone growth. These results suggest that statins could represent a medical treatment for infants and children with TD1 and ACH.

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A statistical survey conducted at the end of 2005 covered 3985 medical facilities across Japan, and 3940 facilities (98.87%) responded. The dialysis population in Japan at the end of 2005 was 257,765, which showed an increase of 9599 patients (3.87%) from the end of the previous year. The number of patients per million was 2017.6. The crude death rate for one year (from the end of 2004 to the end of 2005) was 9.5%. The mean age of the patients who began dialysis (in 2005) was 66.2 years, and the mean age of the entire dialysis population was 63.9 years. The primary diseases of the patients who began dialysis were diabetic renal disease (42.0%) and chronic glomerulonephritis (27.3%). The mean (+/-SD) serum ferritin concentration of all the dialysis patients was 191 (+/-329) ng/mL. The percentages of antihypertensive agents administered to the hemodialysis patients were as follows: calcium-channel blocker, 50.3%; angiotensin-converting enzyme inhibitor, 11.5%; and angiotensin II-receptor blocker, 33.9%. Of the peritoneal dialysis patients, 33.4% used automated peritoneal dialysis devices. Moreover, 7.3% of the peritoneal dialysis patients received dialysis treatment only in the daytime, and 15% received the treatment only at night. Icodextrin solution was used by 37.2% of the peritoneal dialysis patients. The average amount of dialysis solution used by the peritoneal dialysis patients was 7.43 (+/-2.52) L/day and the average amount of removal fluid was 0.81 (+/-0.60) L/day. A peritoneal equilibration test was conducted on 67% of the patients, and the mean dialysate to plasma creatinine ratio was 0.65 (+/-0.13). The annual incidence of peritonitis in the peritoneal dialysis patients was 19.7%. Of the 126 040 patients who responded to the inquiry of the therapeutic situation of peritoneal dialysis, 676 (0.7%) had a history of encapsulated peritoneal sclerosis and 66 (0.1%) were treated for encapsulated peritoneal sclerosis. The mean life expectancy of the dialysis population in 2003 was calculated according to sex and age. Results showed that the mean life expectancy of the dialysis population was approximately 40-60% of that of the general population of the same sex and age.