From Ultrastructure to Mechanics: Characterization of Autologous Leuco-Fibrin-Platelet Membranes for Enhanced Cartilage Regeneration

Osteoarthritis is the most common degenerative joint disorder and a leading cause of pain and disability in adults, characterized by joint inflammation and progressive cartilage degradation. This condition represents a major clinical challenge in modern orthopedics due to the limited regenerative potential of articular cartilage. In recent years, intra-articular autologous blood-derived products have gained increasing attention as promising therapeutic options, providing regenerative support through platelet-derived growth factor (GF) release and exerting anti-inflammatory effects via cytokine secretion. Among these products, the autologous leukocyte-fibrin-platelet membrane (LFPm), produced by the Department of Transfusion Medicine of Belluno Hospital, Italy, is characterized by a high fibrin content, which results in a scaffold with elastic properties and distinct deformability. Moreover, the enhanced concentration of platelet-derived GFs enables a localized release of bioactive molecules that can promote chondrogenesis, while the presence of leukocytes contributes to anti-inflammatory activity. Based on these considerations, this study aimed to characterize LFP membranes from molecular, structural, and mechanical perspectives. Growth factor release was screened by a human growth factor antibody array and quantified using ELISA. Structural integrity was assessed through immunohistochemical analyses of specific components of the extracellular matrix (i.e., fibronectin, vitronectin, fibrinogen). Scanning electron microscopy allowed to obtain high-resolution ultrastructural images. Finally, biomechanical testing was performed to evaluate LFPm response to mechanical loads resembling the stress conditions encountered in the articular environment. Overall, the collected evidence supports the regenerative potential of LFPm ascribable to its structural and biomechanical properties, highlighting its suitability for autologous transplantation in the treatment of osteoarthritis.