Showing papers by "Vladimir Mironov published in 2001"

Regaining chondrocyte phenotype in thermosensitive gel culture.

Abstract: Chondrocyte tissue engineering continues to be a challenging problem. When chondrocytes are duplicated in vitro, it is imperative to obtain an adequate number of cells of optimal phenotype. A temperature-sensitive polymer gel, a copolymer of poly(N-isopropylacrylamide) and acrylic acid (PNiPAAm-co-Aac), has the ability of gelling at 37 degrees C (the lower critical solution temperature, LCST) or above and liquefying below that temperature (Vernon and Gutowska, Macromol. Symp. 1996;109:155-167). The hypothesis of this study was that chondrocytes could (1) duplicate in the copolymer gel; (2) regain their chondrocyte phenotype; and (3) be easily recovered from the gel by simply lowering the temperature below 37 degrees C. Chondrocytes from adult rabbit scapular cartilage were harvested and cultured in a monolayer culture until confluency (approximately 2 weeks). Next, the cells were harvested and seeded into the copolymer gel and cultured for 2-4 weeks. The phenotype of the cultured cells was then characterized. Two groups of control cultures, monolayer and agarose gel, were used to compare their ability to maintain chondrocyte phenotype. The results showed that chondrocytes isolated from rabbit scapula can re-express chondrocyte phenotype in agarose culture and polymer gel culture but not in monolayer culture. Also, cultured chondrocytes can be easily recovered from polymer gel culture by simply lowering the temperature. This new in vitro method of chondrocyte culture is recommended for chondrocyte propagation and regaining chondrocyte phenotype before cell seeding or transplantation.

Anatomy of tissue engineering.

Abstract: Surgery is an applied anatomy. More recently, a new field within biomedicine, the field of tissue engineering and regenerative medicine, has arisen and can be viewed essentially as applied microscopic anatomy, histology, and developmental biology (Langer and Vacanti, 1993; Lauggenburger and Griffith, 2001). Tissue engineering represents a new phase of anatomical research—a transition from an analytical to a synthetic approach. Frankly speaking, if one wants to know how a watch is working, one must disassemble and then reassemble it. The same is applicable and valid to our knowledge with organ and tissue structure as well as histogenesis, organogenesis, and regeneration. It is difficult to underestimate the solid contribution of both anatomists and cell and developmental biologists to the field of tissue engineering. It was an anatomist, Dr. Ross Harrison, who in 1907 made a significant breakthrough and started pioneering research on cultured nerve cells in vitro. Subsequent improvement of cell culture technique; including the discovery of trypsin and EDTA for cell isolation and separation, and the continued development of protocols for cell isolation, freezing, clonal analysis, and cell culture medium; helped to build the necessary foundation for recent progress in the field. It is also impossible to forget the classic research on cell aggregation and tissue reconstruction. Surprisingly, the term “tissue reconstruction” (Steinberg, 1963) was actually used 30 years before the term “tissue engineering” was introduced (Langer and Vacanti, 1993). Also, the theoretical basis for recent NASA bioreactor-based tissue reconstruction research is the classic paper by German embryologist Johannes Holtfreter (1939) who introduced embryonic “tissue affinity” concepts after finishing his training with Nobel Prize winner H. Spemann. Our goal in this brief special issue is not to provide detailed or exhaustive information, but rather, to provide the readership of The Anatomical Record a sense or “pulse” of recent advances in the field of tissue engineering and to encourage their active participation in its further development. The future will no doubt include anatomists who forge a new anatomical discipline, “human tissue engineered anatomy” and anatomists will lead the way with new scientifically and clinically significant advances. It will be interesting to watch how the concepts and principles described in the old textbooks of histology are transformed into FDA standards for the tissue engineered organs and how the anatomists evolve into the industrial quality control specialists. Anatomy will never die!

Polymer Formulations for Cartilage Repair

Abstract: Regeneration of destroyed articular cartilage can be induced by transplantation of cartilage cells into a defect. The best results are obtained with the use of autologus cells. However, obtaining large amounts of autologus cartilage cells causes a problem of creating a large cartilage defect in a donor site. Techniques are currently being developed to harvest a small number of cells and propagate them in vitro. It is a challenging task, however, due to the fact that ordinarily, in a cell culture on flat surfaces, chondrocytes do not maintain their in vivo phenotype and irreversibly diminish or cease the synthesis of aggregating proteoglycans. Therefore, the research is continuing to develop culture conditions for chondrocytes with the preserved phenotype.