Effects of carrageenin on human synovial cells in vitro: morphology, hyaluronic acid production, growth, and the lysosomal system

3D printed scaffolds based on hyaluronic acid bioinks for tissue engineering: a review

Hyaluronic acid (HA) is widely distributed in human connective tissue, and its unique biological and physicochemical properties and ability to facilitate biological structure repair make it a promising candidate for three-dimensional (3D) bioprinting in the field of tissue regeneration and biomedical engineering. Moreover, HA is an ideal raw material for bioinks in tissue engineering because of its histocompatibility, non-immunogenicity, biodegradability, anti-inflammatory properties, anti-angiogenic properties, and modifiability. Tissue engineering is a multidisciplinary field focusing on in vitro reconstructions of mammalian tissues, such as cartilage tissue engineering, neural tissue engineering, skin tissue engineering, and other areas that require further clinical applications. In this review, we first describe the modification methods, cross-linking methods, and bioprinting strategies for HA and its derivatives as bioinks and then critically discuss the strengths, shortcomings, and feasibility of each method. Subsequently, we reviewed the practical clinical applications and outcomes of HA bioink in 3D bioprinting. Finally, we describe the challenges and opportunities in the development of HA bioink to provide further research references and insights.

Diverse morphological responses of normal human synovial fibroblasts to mononuclear leukocyte products: relationship to prostaglandin production and plasminogen activator activities, and comparison with the effects of purified interleukin 1

Supernatant media from cultured human mononuclear blood leukocytes (MCCM) induced morphological changes in normal human synovial fibroblasts in culture, including the formation of cells with a dendritic or stellate morphology and, less frequently, cells with a striking fenestrated appearance. These changes were fully reversed within 1 h of removing the MCCM. They were inhibited by indomethacin, the glucocorticoids hydrocortisone, prednisolone and dexamethasone, and by colcemid, but not by actinomycin D and only weakly by cycloheximide. The morphological responses to MCCM could be reproduced by MCCM fractions containing interleukin 1-like activity and by purified forms of human interleukin 1 (IL-1), including monocyte-derived IL-1 beta and recombinant IL-1 alpha. These responses were also inhibited by indomethacin, indicating a link with prostanoid production. However, the morphological responses were not related to the stimulation of plasminogen activator activity due to MCCM, MCCM fractions, or IL-1.

Activation of human synovial cells by cholera enterotoxin: correlation of morphological responses with adenylate cyclase activities, and the reversing effects of hyaluronidase

Previously described morphological changes in human synovial cell cultures due to cholera enterotoxin (CT) were studied in relation to activation of adenylate cyclase. A single pulse of CT at nanomolar concentration or less induced at least two-fold activation of adenylate cyclase, which persisted for 7 days or more. The enzyme hyaluronidase was found to cause a rapid reversal of the morphological effects of CT. There was also a reduction in adenylate cyclase activity but only with hyaluronidase concentrations greater than those required to produce maximum reversal of the CT-induced morphological changes. Removal of hyaluronidase was followed by reappearance of the CT-associated morphological effects and a slower reactivation of adenylate cyclase. The mechanism by which hyaluronidase produces the observed changes in synovial cells is not known, but might be related to the dispersal of hyaluronic acid gels bound to the surface of these cells.