446. Gender Differences in the Osteogenic & Chondrogenic Potential of Human Muscle-Derived Stem Cells In Vitro

Abstract

Introduction: It has been shown that murine muscle-derived stem cells (MDSCs) are capable of multipotent differentiation1xSee all References. These murine cells exhibit sexual dimorphism of osteogenic and chondrogenic potentials1xSee all References. Previous studies have shown that male mouse MDSCs (M-MDSCs) differentiate into chondrocytes more effectively and display better cartilage regeneration potentials than female MDSCs (F-MDSCs)2xSee all References. M-MDSCs have also been shown to be more osteogenic and demonstrate more rapid bone formation compared to F-MDSCs1. In vivo murine studies have also demonstrated that M-MDSCs form more bone than F-MDSCs1xSee all References, 3xSee all References. Adipose derived stem cells also display sexual dimorphism in their multipotent differentiation potential4xSee all References. This study further investigates this sexual dimorphism in human muscle-derived stem cells (hMDSCs). Methods: Two populations of human MDSCs, one male and one female, were used in these experiments. (1) Osteogenesis: M- and F-hMDSCs 3D pellets were cultured in osteogenic medium containing 100ng/ml bone morphogenic protein 2 (BMP-2) for 28d according to literature1xSee all References. Cell pellets were fixed in neutral buffered formalin and subjected to micro CT scanning. After scanning, cell pellets were embedded in NEG50 freezing medium for sectioning. Von Kossa staining was used to detect mineralization. Osteocalcin immunohistochemistry (IHC) was used to detect osteogenic differentiation. (2) Chondrogenesis: M- and F-MDSC 3D pellets were cultured for 24d in chondrogenic medium using Stem Pro complete chondrogenic medium. After culture, all pellets were fixed and sectioned. Alcian blue and Col2A1 were used as indicators of chondrogenesis, and the percentage of each pellet stained with Alcian blue staining was quantified. Results: Osteogenesis: MicroCT analysis indicated that M-hMDSCs had significantly more pellet mineralization compared to F-MDSCs (p<0.001) (Fig. 1A, 1BFig. 1A, 1B). Von Kossa staining showed stronger brown-black mineral deposition in male pellets than female pellets (Fig. 1CFig. 1C). Osteocalcin IHC indicated higher expression in male hMDSCs than female hMDSCs (Fig. 1DFig. 1D). Chondrogenesis: Alcian blue staining demonstrated that male cells have stronger blue cartilage matrices than female cells (Fig. 2AFig. 2A). Quantification of the blue matrix indicated significantly more matrix in male hMDSC pellets than female pellets (Fig. 2BFig. 2B). Col2A1 IHC showed stronger staining in male hMDSCs than female hMDSCs (Fig. 2CFig. 2C). Conclusions: Our results suggest that both gender hMDSCs can undergo osteogenic and chondrogenic differentiation, but male hMDSCs are more osteogenic and chondrogenic than female hMDSCs. Therefore, sex difference is an important factor to consider in the development and application of cell-based therapies for bone and articular cartilage repair.View Large Image | Download PowerPoint SlideView Large Image | Download PowerPoint Slide