Stored Leukocyte- and Platelet-Rich Fibrin for Regenerative Therapy

Oral health is an essential component of overall health, especially as it facilitates nutrient absorption, emotional expression, and daily socialization. Good oral health plays a crucial role in promoting both physical and mental development. Oral diseases, despite being highly preventable, are typically neglected in health policy and are gradually becoming a public health problem, affecting over 3.5 billion people globally. Priority oral diseases include untreated dental caries, severe periodontitis, and oral cancers.

Severe periodontitis is the sixth most prevalent human disease, affecting approximately 11.2% of the world's adult population, resulting in a staggering economic burden of $54 million in direct and $25 million in indirect treatment costs. Currently, the treatment of severe periodontitis focuses primarily on subgingival biofilm removal by instrumentation and regenerating or resecting lesions. Compared to open flap debridement, regenerative surgical therapies have been shown to further improve clinical and radiographic outcomes of periodontal disease in the majority of studies. Regenerative periodontal surgery includes guided tissue regeneration, grafting, and the use of biologics, aiming for bone regeneration for stabilizing teeth and dental implants.

Both wound healing and bone regeneration are initiated by the formation of a blood clot, in which various growth factors/chemokines stimulate the migration and proliferation of repair cells. Therefore, the incorporation of biologicals (growth factors or cells) in biomaterials has been explored and suggested as a promising approach to promote bone regeneration. Due to the limitations of these strategies in the translation into a clinical workflow, autologous platelet concentrates (APCs) are in special focus of different research approaches. Leukocyte- and platelet-rich fibrin (L-PRF) is referred to as the second-generation APC, following platelet-rich plasma (PRP), with the benefit of simplified preparation without additives, acting as a scaffold that is highly concentrated in blood-derived growth factors, platelets, and leukocytes. L-PRF has been demonstrated efficacy in regenerative periodontal procedures.

In spite of its excellent safety and efficacy, L-PRF suffers from a “relative” short shelf life, which limits its application. To overcome this limitation, numerous technologies have been investigated. Lyophilization, also known as freezing-drying, is believed to be an effective technique for extending the shelf life of L-PRF. However, the viability of cell components in rehydrated L-PRF and its inflammatory response to stimuli remain unknown. The feasibility of storing L-PRF (non-freezing/lyophilized L-PRF) as an alternative to other periodontal regenerative strategies requires additional investigation.

This project's primary objective is to assess the feasibility of storing L-PRF matrices for future periodontal regenerative treatments.