Efficient derivation and banking of clinical-grade human embryonic stem cell lines in accordance with Japanese regulations.

Introduction: We recently established clinical-grade human embryonic stem cell (hESC) line KthES11 in accordance with current good manufacturing practice standards in Japan. Despite this success, the establishment efficiency was very low at 7.1% in the first period. Methods: To establish clinical-grade hESC lines, we used xeno-free chemically defined medium StemFit AK03N with the LM-E8 fragments instead of feeder cells. The protocol was then optimized, especially in the early culture phase. Results: We established five hESC lines (KthES12, KthES13, KthES14, KthES15, and KthES16) with 45.5% efficiency. All five hESC lines showed typical hESC-like morphology, a normal karyotype, pluripotent state, and differentiation potential for all three germ layers. Furthermore, we developed efficient procedures to prepare master cell stocks for clinical-grade hESC lines and an efficient strategy for quality control testing. Conclusions: Our master cell stocks of hESC lines may contribute to therapeutic applications using human pluripotent stem cells in Japan and other countries.

Generation of clinical-grade human embryonic stem cell line KthES11 according to Japanese regulations.

The human embryonic stem cell line, KthES11, is derived from a normal healthy blastocyst donated for clinical research. The inner cell mass (ICM) was isolated using mechanical dissection and plated on laminin fragments. Cell line derivation, its propagation and storage were performed without feeders in an animal product-free environment according to current Good Manufacturing Practice (cGMP) standards. KthES11 shows a normal karyotype, pluripotent state and differentiation to the three germ layers. The cell line was further validated for sterility, mycoplasma-free, antibiotic residues and specific human pathogens.

Highly efficient cryopreservation of human induced pluripotent stem cells using a dimethyl sulfoxide-free solution.

Human induced pluripotent stem (hiPS) cells have great potential for regenerative medicine and drug discovery. It is essential to establish highly efficient and reliable methods for hiPS cell cryopreservation. We examined cryopreservation of hiPS cells by the vitrification method using a dimethyl sulfoxide Me2SO-free and serum-free medium, VS2E, that uses Euro-Collins solution as a base with 40% (v/v) ethylene glycol and 10% (w/v) polyethylene glycol as cryoprotectants. This combination of vitrification and cryoprotectants resulted in a higher recovery rate of hiPS cells than with a commercially-available vitrification solution, DAP213, which contained Me2SO and serum components. After vitrification and warming, hiPS cells were cultured easily. Even after several subculturing steps, cells expressed undifferentiated cell markers, such as Oct-3/4 and SSEA-4, and also exhibited alkaline phosphatase activity. The pluripotency of hiPS cells was maintained, as demonstrated by teratoma formation upon hiPS cell transplantation into severe combined immunodeficient mice. Thus, we successfully preserved hiPS cells under liquid nitrogen with high efficiency using Me2SO-free vitrification solution and rapid cooling.

Wash-out of DMSO does not improve the speed of engraftment of cord blood transplantation: follow-up of 46 adult patients with units shipped from a single cord blood bank.

BACKGROUND: Prolonged periods of marrow hypoplasia have been a problem in cord blood transplantation. DMSO is thought to produce osmotic shock to the progenitors when the thawed cells are infused into the patients. To solve this problem, a 2x dilution method originally developed in the New York Blood Center showed earlier myeloid engraftment,1 although follow-up clinical studies have not performed. STUDY DESIGN AND METHODS: To clarify the influence of the removal of DMSO by this method on the speed of engraftment in unrelated cord blood transplantation, 46 adult patients with cord blood units processed by the Tokyo Cord Blood Bank from September 1998 to March 31, 2002 were studied. Twenty-four patients received 2.6 +/- 0.71 x 10(7) nucleated cells per kg without washing (nonwashed group), while 22 patients were received 2.7 +/- 0.52 x 10(7) nucleated cells per kg after 2x dilution washing (washed group). RESULTS: The cumulative incidence of engraftment was not significantly different between the two groups. Median neutrophil recovery (>/=5 x 10(9)/L) in the nonwashed and washed groups was 26 and 25 days, respectively, and the median platelet recovery (>/=20 x 10(9)/L) in patients with myeloid engraftment was 44 and 40 days, respectively (NS). On the other hand, the doses of CFCs and CD34+ cells showed the influence on myeloid and platelet recovery. CONCLUSION: A 2x dilution after thawing cord blood did not result in the improvement of myeloid engraftment speed.