Mesenchymal stem cells from adipose tissue which have been differentiated into chondrocytes in three-dimensional culture express lubricin

Abstract

The present study focused on the isolation, cultivation and characterization of human mesenchymal stem cells (MSCs) from adipose tissue and on their differentiation into chondrocytes through the NH ChondroDiff medium. The main aim was to investigate some markers of biomechanical quality of cartilage, such as lubricin, and collagen type I and II. Little is known, in fact, about the ability of chondrocytes from human MSCs of adipose tissue to generate lubricin in three-dimensional (3D) culture. Lubricin, a 227.5-kDa mucinous glycoprotein, is known to play an important role in articular joint physiology, and the loss of accumulation of lubricin is thought to play a role in the pathology of osteoarthritis. Adipose tissue is an alternative source for the isolation of multipotent MSCs, which allows them to be obtained by a less invasive method and in larger quantities than from other sources. These cells can be isolated from cosmetic liposuctions in large numbers and easily grown under standard tissue culture conditions. 3D chondrocytes were assessed by histology (hematoxylin and eosin) and histochemistry (Alcian blue and Safranin-O/fast green staining). Collagen type I, II and lubricin expression was determined through immunohistochemistry and Western blot. The results showed that, compared with control cartilage and monolayer chondrocytes showing just collagen type I, chondrocytes from MSCs (CD44-, CD90- and CD105- positive; CD45-, CD14- and CD34-negative) of adipose tissue grown in nodules were able to express lubricin, and collagen type I and II, indicative of hyaline cartilage formation. Based on the function of lubricin in the joint cavity and disease and as a potential therapeutic agent, our results suggest that MSCs from adipose tissue are a promising cell source for tissue engineering of cartilage. Our results suggest that chondrocyte nodules producing lubricin could be a novel biotherapeutic approach for the treatment of cartilage abnormalities.