Successful scale-up of human embryonic stem cell production in a stirred microcarrier culture system

Future clinical applications of human embryonic stem (hES) cells will require high-yield culture protocols. Currently, hES cells are mainly cultured in static tissue plates, which offer a limited surface and require repeated sub-culturing. Here we describe a stirred system with commercial dextran-based microcarriers coated with denatured collagen to scale-up hES cell production. Maintenance of pluripotency in the microcarrier-based stirred system was shown by immunocytochemical and flow cytometry analyses for pluripotency-associated markers. The formation of cavitated embryoid bodies expressing markers of endoderm, ectoderm and mesoderm was further evidence of maintenance of differentiation capability. Cell yield per volume of medium spent was more than 2-fold higher than in static plates, resulting in a significant decrease in cultivation costs. A total of 10(8) karyotypically stable hES cells were obtained from a unitary small vessel that needed virtually no manipulation during cell proliferation, decreasing risks of contamination. Spinner flasks are available up to working volumes in the range of several liters. If desired, samples from the homogenous suspension can be withdrawn to allow process validation needed in the last expansion steps prior to transplantation. Especially when thinking about clinical trials involving from dozens to hundreds of patients, the use of a small number of larger spinners instead of hundreds of plates or flasks will be beneficial. To our knowledge, this is the first description of successful scale-up of feeder- and Matrigel™-free production of undifferentiated hES cells under continuous agitation, which makes this system a promising alternative for both therapy and research needs.

Successful scale-up of human embryonic stem cell production in a stirred microcarrier culture system.

Future clinical applications of human embryonic stem (hES) cells will require high-yield culture protocols. Currently, hES cells are mainly cultured in static tissue plates, which offer a limited surface and require repeated sub-culturing. Here we describe a stirred system with commercial dextran-based microcarriers coated with denatured collagen to scale-up hES cell production. Maintenance of pluripotency in the microcarrier-based stirred system was shown by immunocytochemical and flow cytometry analyses for pluripotency-associated markers. The formation of cavitated embryoid bodies expressing markers of endoderm, ectoderm and mesoderm was further evidence of maintenance of differentiation capability. Cell yield per volume of medium spent was more than 2-fold higher than in static plates, resulting in a significant decrease in cultivation costs. A total of 10(8) karyotypically stable hES cells were obtained from a unitary small vessel that needed virtually no manipulation during cell proliferation, decreasing risks of contamination. Spinner flasks are available up to working volumes in the range of several liters. If desired, samples from the homogenous suspension can be withdrawn to allow process validation needed in the last expansion steps prior to transplantation. Especially when thinking about clinical trials involving from dozens to hundreds of patients, the use of a small number of larger spinners instead of hundreds of plates or flasks will be beneficial. To our knowledge, this is the first description of successful scale-up of feeder- and Matrigel-free production of undifferentiated hES cells under continuous agitation, which makes this system a promising alternative for both therapy and research needs.

Structure and division of the Golgi complex in Trichomonas vaginalis and Tritrichomonas foetus.

We present observations on the fine structure and the division process of the Golgi complex in the protists Trichomonas vaginalis and Tritrichomonas foetus, parasites of the urogenital tract of humans and cattle, respectively. The Golgi in trichomonads is a prominent structure, associated with striated parabasal filaments to which this organelle seems to be connected. We followed by immunofluorescence and electron microscopy the Golgi in interphasic and mitotic cells. Ultrastructural studies were performed using fast-freezing fixation, immunocytochemistry using antisera to the known adhesins AP65 and AP51, cytochemistry (acid phosphatase, Ca++-ATPase, zinc iodide-osmium tetroxide technique (ZIO), for analysis of distribution of the endoplasmic reticulum and Golgi complex, and Thiéry's techniques), routine and serial thin-sections. Three-dimensional reconstruction, NBD-ceramide, fluorescent lectin (WGA) and nocodazole treatments were also used. We demonstrate that: (1) the Golgi in trichomonads is a single-copy organelle; (2) presents a fenestrated structure; (3) is formed by 8-12 saccules; (4) is connected to the parabasal filaments by thin filamentous bridges; (5) by cytochemistry, presents a positive reaction for the lectin WGA, Ca++-ATPase, acid phosphatase, ZIO and Thiéry's techniques; (6) does not appear to break down at any point of the cell cycle; (7) elongates during the cell cycle by lateral growth; (8) is labeled by anti-glutamylated tubulin antibodies, but it is not fragmented by nocodazole treatment; (9) before mitosis, the already elongated Golgi ribbon undergoes progressive medial fission, cisternae by cisternae, starting at the cisternae adjacent to the cell surface and ending with the cis-most cisternae; (10) the Golgikinesis originates two small Golgi ribbons; (11) the Golgi is intensely labeled with the antisera to the AP65 and AP51 adhesins in T. vaginalis, thus seeming to be a key station in the production of adhesins.