Gelatin microcarriers as an effective adipose-derived stem cells delivery strategy in osteoarthritis treatment

Despite their clinical success, stem cells (SCs) in the treatment of osteoarthritis (OA) are limited by lower retention efficiency and restricted paracrine function. The development of effective SCs culture and delivery systems to maintain or promote SCs paracrine function is urgently needed. In this study, we focused on gelatin microcarriers with different sizes as SCs culture scaffold for OA therapy. The effect of culturing adipose-derived stem cells (ADSCs) on different size microcarriers (180 μm and 320 μm) to promote paracrine function was evaluated. The secretome of ADSCs cultured on microcarriers more effectively regulated macrophages and chondrocytes in a direction favorable to OA healing compared to culture plates. In particular, microcarriers with ADSCs effectively reduced the coefficient of friction at the cartilage interface. Injection low-dose ADSCs without and with different size microcarriers into the knee joints in rats' OA model was achieved. Even better OA therapeutic effects were achieved by using smaller size (higher curvature) microcarriers to deliver ADSCs at low doses. Microcarrier-based cell delivery strategies offer potential solution method for OA therapy.