ABSTRACT: Understanding the basis of osteoarthritis (OA) has seen some interesting advancements in recent years. It has been observed that cartilage degeneration is preceded by subchondral bone lesions, suggesting a key role of this mechanism within the pathogenesis and progression of OA, including the formation of ectopic bone and osteophytes. Moreover, low-grade, chronic inflammation of the synovial lining has gained a central role in the definition of OA pathophysiology, and central immunological mechanisms, innate but also adaptive, are now considered crucial in driving inflammation and tissue destruction. In addition, the role of neuroinflammation and central sensitization mechanisms has been characterized as underlying causes of pain chronicity. This has led to a renewed definition of OA, which is now intended as a complex multifactorial joint pathology caused by inflammatory and metabolic factors underlying joint damage. Since this evidence can directly affect the definition of the correct therapeutic approach to OA, an improved understanding of these pathophysiological mechanisms is fundamental. This review provides an overview of the most updated evidence on OA pathogenesis; it presents the most recent insight on the pathophysiology of OA, describing the interplay between immunological and biochemical mechanisms proposed to drive inflammation and tissue destruction, as well as central sensitization mechanisms. Moreover, although the therapeutic implications consequent to the renewed definition of OA are beyond this review scope, some suggestions for intervention have been addressed.

Palmitoylethanolamide (PEA) has been prescribed for neuropathic pain for several years. This study is mainly addressed to summarize what has been published on the topic in the last decades, and how appropriate the numerous prescriptions are. Among others, it examines the innovative EquiPEA^® patent, which aims to address obstacles encountered with conventional PEA formulations. EquiPEA^® seems to partially ameliorate the bioavailability and the targeted distribution. It seems to introduce novel advancements that have the potential to enhance the therapeutic effectiveness of PEA in terms of its anti-inflammatory, antioxidant, and analgesic properties. The deep literature analysis aims to examine the potential advantages of this innovative formulation, in the context of several pathological conditions that may benefit from this molecule. In particular, it investigates the potential enhanced bioavailability and targeted delivery system of EquiPEA^®. Also, it tries to understand if it can modernize the field of therapy based on PEA, thus offering a better treatment option for individuals with long-term inflammation, oxidative stress, and neuropathic or mixed pain with a neuropathic component. The study examines the possible impact of EquiPEA^® on personalized medicine strategies and its potential for translation into clinical practice. It analyses the possibilities that EquiPEA^® has in enhancing patient outcomes in a range of central nervous system and inflammatory conditions. This narrative review makes a valuable contribution to the ongoing comprehension of PEA therapy. It establishes a foundation for further exploration in research and potential uses in clinical settings.