Green Foaming of Biologically Extracted Chitin Hydrogels Using Supercritical Carbon Dioxide for Scaffolding of Human Osteoblasts.

Chitin is a structural polysaccharide abundant in the biosphere. Chitin possesses a highly ordered crystalline structure that makes its processing a challenge. In this study, chitin hydrogels and methanogels, prepared by dissolution in calcium chloride/methanol, were subjected to supercritical carbon dioxide (scCO2) to produce porous materials for use as scaffolds for osteoblasts. The control of the morphology, porosity, and physicochemical properties of the produced materials was performed according to the operational conditions, as well as the co-solvent addition. The dissolution of CO2 in methanol co-solvent improved the sorption of the compressed fluid into the hydrogel, rendering highly porous chitin scaffolds. The chitin crystallinity index significantly decreased after processing the hydrogel in supercritical conditions, with a significant effect on its swelling capacity. The use of scCO2 with methanol co-solvent resulted in chitin scaffolds with characteristics adequate to the adhesion and proliferation of osteoblasts.

Synovial membrane mesenchymal stem cells for cartilaginous tissues repair.

BACKGROUND: The present review is focused on general aspects of the synovial membrane as well as specialized aspects of its cellular constituents, particularly the composition and location of synovial membrane mesenchymal stem cells (S-MSCs). S-MSC multipotency properties are currently at the center of translational medicine for the repair of multiple joint tissues, such as articular cartilage and meniscus lesions. METHODS AND RESULTS: We reviewed the results of in vitro and in vivo research on the current clinical applications of S-MSCs, surface markers, cell culture techniques, regenerative properties, and immunomodulatory mechanisms of S-MSCs as well as the practical limitations of the last twenty-five years (1996 to 2021). CONCLUSIONS: Despite the poor interest in the development of new clinical trials for the application of S-MSCs in joint tissue repair, we found evidence to support the clinical use of S-MSCs for cartilage repair. S-MSCs can be considered a valuable therapy for the treatment of repairing joint lesions.

Behavior of multipotent stem cells isolated in mobilized peripheral blood from sheep after culture with human chondrogenic medium.

Today, regenerative medicine requires new sources of multipotent stem cells for their differentiation to chondrocytes using the mediums of differentiation available in the market. This study aimed to determine whether the Mesenchymal Stem Cells (MSCs) isolated from Mobilized Peripheral Blood (MPB) in sheep using the Granulocyte Colony-Stimulating Factor (G-CSF), have the ability of first acquire a fibroblast-like morphology after being forced out of the bone marrow niche by G-CSF and second, if the cells have the capacity to express collagen type-II α I in primary culture using a human commercial media of differentiation. Six Suffolk male sheep with age of 2 years were mobilized using G-CSF. One subcutaneous injection of 10 mcg per kilogram of bodyweight were administered every 24 h during three consecutive days. At day four, a sample of 20 mL of peripheral blood was harvested, afterwards, monocytes cells were separated by ficoll gradient. The mobilized MSCs were expanded in primary culture in DMEM medium supplemented with 10% adult sheep serum for three weeks and characterized by an antibody panel for surface markers: CD105, CD90, CD73, CD34, and CD45, before and after primary culture. Subsequently, an aliquot of cells in the first pass were cultured in a commercial human chondrogenic medium for three weeks. As a result, the percentage of surface markers for MSCs (CD105, CD90, CD73) in expanded cells in primary culture significantly increased, at the same time a decrease in the markers for hematopoietic cells (CD34 and CD45) was observed and the cells morphology was fibroblast-like. After three weeks of differentiation culture, the immunofluorescence analysis evidenced the expression of collagen-type-II. It was concluded that Mesenchymal Stem Cells isolated from mobilized peripheral blood in sheep have the ability to pre-differentiate into chondral like cells and express collagen type-II when are stimulated with a human commercial chondrogenic medium in monolayer culture.