Bone tissue engineering is not widely used in clinical treatment. Two main reasons hide behind this: (1) the seed cells are difficult to obtain and (2) the process of tissue engineering bone construction is too complex and its efficiency is still relatively low. It is foreseeable that in the near future, the problem of seed cell sources could be solved completely in tissue engineering bone repair. As for the complex process and low efficiency of tissue engineering bone construction, usually two strategies would be considered: (1) the construction strategy based on injectable bone tissue and (2) the construction strategy based on osteogenic cell sheets. However, the application of injectable bone tissue engineering (iBTE) strategy and osteogenic cell sheet strategy is limited and they could hardly be used directly in repairing defects of large segmental bone, especially load-bearing bone. In this study, we built an osteogenic micro-tissue with simple construction but with a certain structure and composition. Based on this, we established a new iBTE repair strategy—osteogenic micro-tissue in situ repair strategy, mainly targeting at solving the problem of large segmental bone defect. The steps are as follows: (1) Build the biodegradable three-dimensional scaffold based on the size of the defect site with 3D printing rapid prototyping technology. (2) Implant the three-dimensional scaffold into the defect site. This scaffold is considered as the “steel framework” that could provide both mechanical support and space for bone tissue growth. (3) Inject the osteogenic micro-tissue (i.e., the “cell-extracellular matrix” complex), which could be considered as “concrete,” into the three-dimensional scaffold, to promote the bone tissue regeneration in situ. Meanwhile, the digested cells were injected as the compared group in this experiment. After 3 months, the effect of in situ bone defect repair of osteogenic micro-tissue and digested cells was compared. It is confirmed that osteogenic micro-tissue could achieve a higher efficiency on cell usage and has a better repair effect than the digested cells. Osteogenic micro-tissue repairing strategy would be a more promising clinical strategy to solve the problem of large segmental bone defect.

Background: Previous studies showed Cell free fat extract (CEFFE) and Platelet rich plasma (PRP) could effectively accelerate wound healing. However, the comparative study on curative effect is still lacking. A systematic comparison could provide more theoretical support and laboratory basis for the clinical application of CEFFE and PRP.Objective: To compare the efficacy of CEFFE and PRP in promoting skin wound repair.Methods: CEFFE and PRP were prepared according to the literature. The wound repair related factors were measured and compared. In vitro, the effects of both on cell migration, proliferation and tube formation were compared. In vivo, wound healing rate was measured on the 1st, 3rd, 9th, and 12th days after skin injury and treatment. Then the specimens were cut off for histological analysis.Results: Although the total protein content of PRP was significantly around 19 times higher than that of CEFFE, there was no statistical difference in the content of BDNF, EGF and VEGF between CEFFE and PRP. Even the NT-3 content of CEFFE was just slightly higher than that of PRP. The concentration of b-FGF, HGF and TGF-β and PDGF-BB in PRP is higher than that in CEFFE, but there is only a very small difference between them. In vitro, PRP showed better efficacy than CEFFE in promoting fibroblast proliferation while there was no significant difference in promoting angiogenesis and fibroblast migration. Both PRP and CEFFE could significantly promote wound healing in mice. There was no statistical difference in wound healing between CEFFE and PRP groups in vivo. Immunohistochemical staining of Ki67&CD31 showed that there was no significant difference between PRP and CEFFE groups.Conclusion: The effect of PRP and CEFFE in promoting wound healing was similar. In clinical practice, the acquisition of PRP is relatively more convenient. Containing no cells, CEFFE has the advantage of easier preservation. For patients who have discarded adipose tissue, or contraindications to PRP technology, CEFFE technology may provide a new option for skin wound repair.

Diabetic wound is a significant clinical challenge, and stem cell therapy has shown great potential. This study explores the role of mesenchymal stem cell (MSC) spheroids (Sp‐MSCs) in healing diabetic wounds and the use of autologous plasma‐rich platelet fibrin (PRF) as a scaffold for Sp‐MSCs. Through activation of the coagulation system, PRF offers a protective fibrin shield for Sp‐MSCs to promote the rapid recovery migration and proliferation of MSCs while maintaining the activity of Sp‐MSCs in an inflammatory overload environment by activating the related genes of Integrin‐β1‐vascular endothelial growth factor (VEGF), and Wnt/β‐catenin pathways. The inclusion of Sp‐MSCs accelerates the gelation of PRF and results in improved mechanical strength. Additionally, PRF enhances the repair function of Sp‐MSCs, creating a favorable microenvironment for angiogenesis. In the wound model of diabetic mice, the combination of PRF with Sp‐MSCs accelerates wound healing. Results show that this combination significantly promotes wound repair and regulates the immune microenvironment. The study suggests that PRF is a promising bio‐derived scaffold for stem cell applications in diabetic wounds, offering new directions for stem cell therapy and biomimetic scaffold material development.

At present, many laboratories and hospitals all over the world are attempting and exploring the clinical transformation of this tissue engineered bone graft (TEBG) strategy. Many successful cases of bone tissue engineering (BTE) repair were based on young individuals. But there are little studies about the effectiveness of TEBG strategy in physiological aged individuals. In this research, we studied whether aging factor has influence on the skull repair effect of Fetal-TEBG, at the level of the large animal models. We used the fetal bone marrow stromal cells (Fetal-BMSCs) as the seed cells, combining the decalcified bone matrix (DBM) scaffolds, to repair the skull defects of the aged goats and the young goats. The repair effects on both aged goat and young goat were compared by Micro-CT and histology examination. The skull defects of the young goats could be repaired better than that of the aged goats after 6 months by Fetal-TEBG; In the aged goats, although not completely repaired, the defects repaired by Fetal-TEBG was better than that repaired by the Control DBM scaffold. Aging factor has impact on the bone repair effect of Fetal-TEBG; and the BTE strategy is still efficacious even in the aged individuals. The improvement of the aged state may promote the repair effect of the BTE in the aged individuals.

Wound development and healing involve intricate genetic and molecular processes, posing significant clinical management challenges. The objective of this study was to assess commonly used fat extracts' efficacy and safety (autologous fat, stromal vascular fraction and adipose‐derived stem cells) in wound healing, particularly for refractory wounds, with the goal of providing evidence in clinical use. After a systematic review, 21 randomised controlled trials were included in our study. Based on the classification of human fat products, our meta‐analysis revealed that the use of human fat products could speed healing rate, shorten healing time and achieve more complete healing, with statistically significant differences in outcome indicators when compared to conventional treatments. The analysis of histological findings across various studies indicated that fat extracts can promote epithelialization, collagen deposition and vascularization, thereby facilitating tissue regeneration and reducing inflammatory reactions. There were potential benefits to reducing patient pain levels after using adipose extracts. Furthermore, we analysed and summarised adverse events indicating the safe and effective clinical use of human fat products in wound treatment. Our research findings supported the efficiency of human fat products and demonstrated a high degree of safety in the clinical practice of wound management.