Chondrogeneic Potential of MSC from Different Sources in Spheroid Culture.

We performed a comparative study of the proliferative potential of human mesenchymal stromal cells (MSC) from three sources (tooth pulp, adipose tissue, and Wharton's jelly) in spheroid culture; human chondroblasts served as the positive control. Histological examination revealed signs of chondrogenic differentiation in all studied cell cultures and the differences in the volume and composition of the extracellular matrix. Spheroids formed by MSC from the tooth pulp and Wharton's jelly were characterized by low content of extracellular matrix and glycosaminoglycans. Spheroids from adipose tissue MSC contained maximum amount of the extracellular matrix and high content of glycosaminoglycans. Chondrocytes produced glycosaminoglycan-enriched matrix. Type II collagen was produced by chondrocytes (to a greater extent) and adipose tissue MSC (to a lesser extent). The results of our study demonstrate that MSC from the adipose tissue under conditions of spheroid culturing exhibited maximum chondrogenic potential.

Formation of Tissue-Engineered Construct of Human Cartilage Tissue in a Flow-Through Bioreactor.

We performed culturing of a cell-engineered construct of human cartilage tissue consisting of biopolymer microstructured collagen-containing hydrogel, human adipose tissue mesenchymal stromal cells, and induction chondrogenic culture medium in a specially designed flow-through bioreactor. On day 16 of the experiment, human adipose tissue mesenchymal stromal cells acquired flattened shape typical for chondroblasts, demonstrated high proliferative activity, and formed extracellular matrix. The observed histological changes in the cultured system attested to the beginning of the formation of a tissue-engineered construct of human cartilage tissue.

[Modification of a method of cell enucleation using cytochalasin B and the study of cytoplast viability]. / Modifikatsiia metoda énukleatsii kletok s pomoshch'iu tsitokhalazina B i izuchenie zhiznesposobnosti tsitoplastov.

The modification of Prescott's (Prescott et al., 1972) method of enucleation in vitro was described. A special teflon chamber faciliatating the enucleation of monolayer cultured cells to produce cytoplasts and karyoplasts was constructed. Mouse L-cells were enucleated by exposing to cytochalasine B (10 gamma/ml) followed by centrifugation. The fraction of cells enucleated in the chamber was about 98%. The life time of cytoplasts in cultural medium after their enucleation was 48 hours (sometimes 56-72 hours) as tested by vital neutral red staining. The cytoplasts that survived were shown to accumulate large lysosomes, and the evidence of appearing ring-like fibrillar structures was provided using a simple technique of cytoskeleton observation under light microscope.

[In vitro phenomenon of beta cell migration from fetal calf pseudoislets]. / Fenomen migratsii beta-kletok iz psevdoostrovkov podzheludochnoi zhelezy plodov krupnogo rogatogo skota in vitro.

Pseudoislets--pancreatic microfragments containing a lot of beta-cells and capable of insulin secretion in vitro-were obtained from 12 fetal calf pancreata by the use of collagenase. Morphological and functional changes of the pseudoislets were studied during culture. We found a rapid migration of beta-cells out of the pseudoislets to the bottom of plastic tissue culture plates. This process was accompanied by a significant decrease of insulin-secreting capacity of the floating microfragments. This should be taken into consideration in cases when pseudoislets are prepared for transplantation in order to avoid beta-cell loss.

[Some characteristics of the histological structure of the fetal bovine pancreas]. / O nekotorykh osobennostiakh gistologicheskogo stroeniia podzheludochnoi zhelezy plodov krupnogo rogatogo skota.

Some properties of histological structure of fetal bovine pancreas were demonstrated using light microscopic methods. The different forms of acino-insular complexes were described: 1) acino-insular complexes with single B-cells including epithelial layer of acini; 2) acino-insular complexes with segmental (sector) localization of insular cell groups; 3) acino-insular complexes with small and more large groups of endocrine cells timely contacted with acini; 4) acino-insular complexes at the stage of separation of endocrine cell groups (microislets) from acini. The consideration of acino-insular complexes in morphogenesis of bovine endocrine pancreas in discussed.

[Cultures of islet cells obtained from the fetal bovine pancreas]. / Kul'tury ostrovkovykh kletok, poluchennye iz podzheludochnoi zhelezy plodov krupnogo rogatogo skota.

The pancreas from bovine fetuses of 27-35 cm crown-rump length were used as a source of islet cell cultures. Pancreatic tissue was treated by collagenase, filtered through the metal sieve and incubated in MEM for 24 h. Using this method, cultures similar to so-called pseudo-islets were obtained. Aldehyde-fuchsin staining and electron microscopy revealed a significant number of beta-cells within the pseudo-islets, the insulin-producing activity of which was confirmed by RIA.

[Floating cultures obtained from the thyroid of human fetuses]. / Flotiruiushchie kul'tury, poluchaemye iz shchitovidnoi zhelezy plodov cheloveka.

Floating cultures were obtained from fetal human thyroid. The method for preparing the cultures was described. The floating cultures finally consist of epithelial cell group--thyrocytes, stroma and one or some layers of fibroblastic cover. Thyroid hormones (thyroxine, triiodothyronine) were revealed during the cultivation period (40 days). Floating cultures obtained from fetal human thyroid can be used in clinical transplantation science.

[Preparation of liver cultures from human embryos]. / Poluchenie kul'tur iz pecheni émbrionov cheloveka.

The cultures were obtained from 9-12-week-old human embryonic liver. 24-36 hours after seeding the cultures containing a multilayer focus of adhesion and a monolayer growth zone were formed. The growth zone contained hepatocytes with bile pigment granules in the cytoplasm. The formation of culture monolayer coincided with the elimination of hemopoietic cells.

[Effect of xenotransplantation of islet cell culture on the course of alloxan diabetes in rats fed a diet varying in protein content]. / Vliianie ksenotransplantatsii kul'tur ostrovkovykh kletok na techenie alloksanovogo diabeta u krys, nakhodivshikhsia na diete s raznym soderzhaniem belka.

The authors present data on the protective effect of newborn rabbits pancreatic islet cell culture xenotransplantation of Langerhans' islet beta-cells of rats with alloxan diabetes. This effect was the most marked in rats fed diets with normal or increased protein content. The authors discuss a possible stimulating effect of rabbit islet cell culture xenotransplantation on regeneration processes in recipient rat pancreatic islets. This effect was better pronounced in rats kept on rations with increased protein content. Further experiments will help more accurately define the indications for therapy of insulin-dependent diabetes mellitus by xenotransplantations of islet cell cultures.

[Aggregates of islet cells, their structure and insulin-producing activity during cultivation in vitro]. / Agregaty ostrovkovykh kletok, ikh struktura i insulinprodutsiruiushchaia aktivnost' v usloviiakh kul'tivirovaniia in vitro.

Purified rat islets were dissociated into single-cell suspension with an EDTA-Trypsin treatment. During a stationary culture in vitro the islet cells reassociated forming aggregates (neoislets). Electron microscopy revealed that the aggregates consisted mostly of beta-cells and not numerous alpha-cells. They showed a good insulin-secreting capacity and were able to increase insulin release in response to glucose plus theophylline. The lack of passenger leukocytes makes the neoislets particularly suited for experimental and clinical transplantation.