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Hair loss, or alopecia, is associated with several psychosocial and medical comorbidities, and it remains an economic burden to individuals and the society. Alopecia is attributable to varied mechanisms and features a multifactorial predisposition, and the available conventional medical interventions have several limitations. Thus, several therapeutic strategies for alopecia in regenerative medicine are currently being explored, with increasing evidence suggesting that mesenchymal stem cell (MSC) implantation, MSC-derived secretome treatment, and blood-derived platelet-rich plasma therapies are potential treatment options. In this review, we searched the Cochrane Library, MEDLINE (PubMed), EMBASE, and Scopus using various combinations of terms, such as "stem cell," "alopecia," "hair loss," "Androgenetic alopecia," "male-pattern hair loss," "female-pattern hair loss," "regenerative hair growth," "cell therapy," "mesenchymal stem cells," "MSC-derived extracellular vesicles," "MSC-derived exosomes," and "platelet-rich plasma" and summarized the most promising regenerative treatments for alopecia. Moreover, further opportunities of improving efficacy and innovative strategies for promoting clinical application were discussed., Competing Interests: The authors have no conflicts of interest to declare for this work., (© 2022 The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.)

Current trends indicate a growing interest among healthcare specialists and the public in the use of regenerative medicine-based approaches for skin regeneration. The approaches are categorised in either cell-based or cell-free therapies and are reportedly safe and effective. Cell-based therapies include mesenchymal stem cells (MSCs), tissue induced pluripotent stem cells (iPSCs), fibroblast-based products, and blood-derived therapies, such as those employing platelet-rich plasma (PRP) products. Cell-free therapies primarily involve the use of MSC-derived extracellular vesicles/exosomes. MSCs are isolated from various tissues, such as fat, bone marrow, umbilical cord, menstrual blood, and foetal skin, and expanded ex vivo before transplantation. In cell-free therapies, MSC exosomes, MSC-derived cultured media, and MSC-derived extracellular vesicles are collected from MSC-conditioned media or supernatant. In this review, a literature search of the Cochrane Library, MEDLINE (PubMed), EMBASE, and Scopus was conducted using several combinations of terms, such as 'stem', 'cell', 'aging', 'wrinkles', 'nasolabial folds', 'therapy', 'mesenchymal stem cells', and 'skin', to identify relevant articles providing a comprehensive update on the different regenerative medicine-based therapies and their application to skin regeneration. In addition, the regulatory perspectives on the clinical application of some of these therapies in Japan are highlighted., Competing Interests: The authors have no conflicts of interest to declare for this work., (© 2022 The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.)

Platelet-rich plasma (PRP) is a widely accepted treatment approach and has heightened the quality of care among physicians. PRP has been used over the last decade to boost clinical results of plastic therapies, periodontal surgery and intra-bony defects. According to certain research, elevated levels of PRP growth factors that could promote tissue repair and have the potential for PRP to be beneficial in regenerating processes that Maxillofacial and Oral Surgeons, Veterinary Officers, Athletic medicine specialists and Dermatologists have long admired. PRP is an autologous whole blood fraction that has a heavy amount of a variety of growth factors such as epidermal growth factor (EGF), Vascular Endothelial Growth Factor (VEGF), hepatocyte growth factor (HGF), fibroblast growth factors (FGFs), transforming growth factor beta-1 (TGF-b), insulin-like growth factor-I (IGF-I) and platelet-derived growth factor (PDGF) which can facilitate repair and regeneration. Moreover, a clinical trial of PRP in severe angina patients has shown its excellent safety profile. However, PRP is a very complex biological substance with an array of active biomolecules, its functions are yet to be fully clarified. In-addition, there was insufficient work assessing possible cardiovascular tissue benefits from PRP. Thus, it still remains necessary to identify the most clinically important cardiovascular applications and further research in clinical scenario need to be validated., Competing Interests: The authors have no conflict of interests., (© 2022 The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.)

Freeze-drying methods not only enable the delivery of growth factors using platelets, but also extend the shelf-life of platelet concentrates. The present study shows the clinical results of treating knee osteoarthritis with freeze-dried platelet-derived factor concentrate (PFC). While it improved pain, activities of daily living, sports and recreational activities, and knee-related quality of life, it did not significantly improve symptoms other than pain, such as restricted range of motion and mechanical symptoms. As such, the treatment effect may be attributed to anti-inflammatory action rather than actual cartilage regeneration.

Autologous biologics, defined as platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMC), are cell-based therapy treatment options in regenerative medicine practices, and have been increasingly used in orthopedics, sports medicine, and spinal disorders. These biological products are produced at point-of-care; thereby, avoiding expensive and cumbersome culturing and expansion techniques. Numerous commercial PRP and BMC systems are available but reports and knowledge of bio-cellular formulations produced by these systems are limited. This limited information hinders evaluating clinical and research outcomes and thus making conclusions about their biological effectiveness. Some of their important cellular and protein properties have not been characterized, which is critical for understanding the mechanisms of actions involved in tissue regenerative processes. The presence and role of red blood cells (RBCs) in any biologic has not been addressed extensively. Furthermore, some of the pathophysiological effects and phenomena related to RBCs have not been studied. A lack of a complete understanding of all of the biological components and their functional consequences hampers the development of clinical standards for any biological preparation. This paper aims to review the clinical implications and pathophysiological effects of RBCs in PRP and BMC; emphasizes hemolysis, eryptosis, and the release of macrophage inhibitory factor; and explains several effects on the microenvironment, such as inflammation, oxidative stress, vasoconstriction, and impaired cell metabolism.

Introduction: Platelet-rich plasma (PRP) has been shown to be effective in treating partial tears of the ulnar collateral ligament (UCL) of the elbow in overhead throwing athletes, but it is still unknown whether it has a role in complete tears. The aim of this study was to assess the effectiveness of PRP in treating complete as well as partial UCL tears. We hypothesized that trephination of the injured UCL followed by injection with PRP can promote healing of both partial and complete tears., Methods: Thirty-four baseball players with partial or complete UCL tears confirmed by magnetic resonance imaging (MRI) were included in the study. They were all recalcitrant to more than two months of rest and physical therapy. Under ultrasound guidance, trephination of the UCL was performed using an 18-gauge needle, followed by PRP injection. Visual analog scale (VAS) scores, Disabilities of the Arm, Shoulder, and Hand (DASH) sports module scores, and sonographic ulnohumeral joint space measurements with valgus stress were all obtained prior to the procedure and six months after., Results: Twenty-six of 30 athletes were able to return to sport with pre-injury level of play within six months after the procedure, at an average time of 12.4 weeks (range: 10-18). Four subjects needed surgical treatment for persistent UCL insufficiency. The average follow-up was 54.2 weeks (range: 26-148). The average VAS and DASH scores improved from 53.5 to 17.2 (p < 0.0001) and from 81.7 to 24.2 (p < 0.0001), respectively. The average ulnohumeral joint space opening with valgus stress decreased from 3.81 mm to 3.45 mm (p = 0.018). Subgroup analysis by injury location revealed that the average VAS score improved from 48.2 to 8.6 (p < 0.0001) and from 64.0 to 34.5 (p = 0.0023) in proximal and distal tears, respectively. The average DASH score improved from 83.8 to 17.8 (p = 0.0001) and from 77.5 to 36.7 (p < 0.0001) in proximal and distal tears, respectively. The average ulnohumeral joint space opening with valgus stress decreased from 3.64 to 3.21 mm (p = 0.003) and from 4.14 to 3.92 mm (p = 0.0023) in proximal and distal tears, respectively. There was one case with a proximal tear that needed surgical management for failure of treatment, while there were three cases needing surgery in those with distal tears., Conclusion: Ultrasound-guided PRP injection following trephination can be an effective treatment option for both partial and complete UCL tears of the elbow, especially proximal tears. The use of this technique for complete UCL tears may allow more athletes to avoid surgery and enable them to return to play faster.