IMPROVING AUTOLOGOUS CHONDROCYTE IMPLANTATION USING LYOPHILIZED HUMAN PLATELET LYSATE

Fetal bovine serum (FBS) and human autologous serum are commonly used as supplements for chondrocyte culture in autologous chondrocyte implantation (ACI). However, FBS carries risks of pathogen contamination, ethical concerns, and inconsistent composition, while autologous serum is limited by availability and patient-specific factors that can impair chondrocyte quality. Platelet-derived products, such as our in-house developed lyophilized human platelet lysate (L-HPL) pooled from 16 donors [1], offer a promising, allogenic alternative. This study evaluated the potential of L-HPL to enhance chondrocyte quality for ACI. Human chondrocytes cultured with L-HPL were compared to those cultured with FBS in terms of in vitro multiplication, chondrogenicity and immunomodulatory potential. Cartilage tissue was harvested from section blocs during knee arthroplasty of six patients. Chondrocytes were cultured in medium containing 7% L-HPL or 10% FBS. Outcomes assessed included proliferation, viability, morphology, chondrogenic redifferentiation in 3D spheroids, and immunomodulatory potential. Chondrogenic capacity was analyzed via total protein content, proteoglycan content, and collagen II staining. Inflammatory mediator secretion was quantified before, during, and after IL-1β stimulation using multiplex immunoassays. Chondrocytes cultured with L-HPL showed significantly higher proliferation, viability, and cell numbers than FBS-cultured cells. High-content imaging revealed longer actin segments and reduced actin compactness in the L-HPL group. With and without chondrogenic stimulus with TGF-β1, spheroids derived from L-HPL-cultured chondrocytes exhibited greater protein and proteoglycan content, larger size, and higher collagen II expression. L-HPL-cultured cells secreted more anti-inflammatory IL-10 and significantly less pro-inflammatory IL-17A and IL-18 compared to FBS-cultured cells during and after IL-1β exposure. Using L-HPL as a culture supplement significantly enhances the quantity and quality of human chondrocytes, producing larger, more robust spheroids with improved cartilage-specific matrix expression. Additionally, L-HPL-derived chondrocytes exhibit an anti-inflammatory profile, potentially improving post-operative outcomes. These findings suggest that L-HPL could increase the success of ACI while reducing pre-therapeutic failures. Next steps include GMP-compliant L-HPL production for clinical translation of optimized ACI.