Tissue Engineering. Part B, Reviews最新文献

Peripheral nerve regeneration after trauma poses a substantial clinical challenge that has already been investigated for many years. Infiltration of immune cells is a critical step in the response to nerve damage that creates a supportive microenvironment for regeneration. In this work, we focus on a special type of immune cell, macrophage, in addressing the problem of neuronal regeneration. We discuss the complex endogenous mechanisms of peripheral nerve injury and regrowth vis-à-vis macrophages, including their recruitment, polarization, and interplay with Schwann cells post-trauma. Furthermore, we elucidate the underlying mechanisms by which exogenous stimuli govern the above events. Finally, we summarize the necessary roles of macrophages in peripheral nerve lesions and reconstruction. There are many challenges in controlling macrophage functions to achieve complete neuronal regeneration, even though considerable progress has been made in understanding the connection between these cells and peripheral nerve damage.

Developing an in vitro model of gingival connective tissue that mimics the original structure and composition of gingiva for clinical grafting is relevant for personalized treatment of missing gingiva. Using tissue engineering techniques allows bypassing limitations encountered with existing solutions to increase oral soft tissue volume. This review aims to systematically analyze the different currently existing cellularized materials and technologies used to engineer gingival substitutes for in vivo applications. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. An electronic search on PubMed, Scopus, Web of Science, and Cochrane Library databases was conducted to identify suitable studies. In vivo studies about gingival substitutes and grafts containing oral cells compared with a control to investigate the graft remodeling were included. Risk of bias in the included studies was assessed using the Systematic Review Center for Laboratory animal Experimentation (SYRCLE) 10-item checklist. Out of 631 screened studies, 19 were included. Animal models were mostly rodents, and the most used implantation was subcutaneous. According to the SYRCLE tool, low-to-unclear risk of bias was prevalent. Studies checked vascularization and extracellular remodeling up to 60 days after implantation of the cellularized biomaterial. Cells used were mostly fibroblasts and stem cells from oral origin. Grafts presenting vascularization potential after implantation were produced by tissue engineering technologies including cell seeding or embedding for 14, cell sheets for 2, microsphere for 1, and extrusion 3D bioprinting for 2. Components used to build the scaffold containing the cells are all naturally derived and are mainly fibrin, gelatin, collagen, agarose, alginate, fibroin, guar gum, hyaluronic acid, and decellularized extracellular matrix. The most recurring crosslinking method was using chemicals. All studies except one reported vascularization of the graft after implantation, and some detailed extracellular matrix remodeling. Current solutions are not efficient enough. By assessing the relevant studies on the subject, this systematic review showed that a diversity of cellularized biomaterials substituting gingival connective tissue enables vascularization and extracellular remodeling. Taking the results of this review into account could help improve current bio-inks used in 3D bioprinting for in vivo applications compensating for gingival loss.

The dura mater, the furthest and strongest layer of the meninges, is crucial for protecting the brain and spinal cord. Its biomechanical behavior is vital, as any alterations can compromise biological functions. In recent decades, interest in the dura mater has increased due to the need for hermetic closure of dural defects prompting the development of several substitutes. Collagen-based dural substitutes are common commercial options, but they lack the complex biological and structural elements of the native dura mater, impacting regeneration and potentially causing complications like wound/postoperative infection and cerebrospinal fluid (CSF) leakage. To face this issue, recent tissue engineering approaches focus on creating biomimetic dura mater substitutes. The objective of this review is to discuss whether mimicking the mechanical properties of native tissue or ensuring high biocompatibility and bioactivity is more critical in developing effective dural substitutes, or if both aspects should be systematically linked. After a brief description of the properties and architecture of the native cranial dura, we describe the advantages and limitations of biomimetic dura mater substitutes to better understand their relevance. In particular, we consider biomechanical properties' impact on dura repair's effectiveness. Finally, the obstacles and perspectives for developing the ideal dural substitute are explored.

This research is dedicated to uncovering the evolving trends, progressive developments, and principal research themes in tissue engineering and regenerative medicine for rotator cuff injuries, which spans the past two decades. This article leverages visualization methodology to provide a clear and comprehensive portrayal of the dynamic landscape within the field. We compiled 758 research entries centered on the application of tissue engineering and regenerative medicine in treating rotator cuff injuries, drawing from the Web of Science Core Collection database and covering the period from 2003 to 2023. Analytical tools such as VOSviewer, CiteSpace, and GraphPad Prism were used. We conducted comprehensive analyses to discern the general characteristics, historical evolution, key literature, and pivotal keywords within this research field. This comprehensive analysis enabled us to identify emerging focal points and current trends in the application of tissue engineering and regenerative medicine for addressing rotator cuff injuries. The compilation of 758 articles in this study indicates a consistent upward trajectory in publications concerning tissue engineering and regenerative medicine for rotator cuff injuries. The scholarly contributions from the United States, China, and South Korea have notable influence on the progression of this research area. The analysis delineated ten specific research subdomains, including fatty infiltration, tears, tissue engineering, shoulder pain, tendon repair, extracellular matrix (ECM), and platelet-rich plasma growth factors. Noteworthy is the recurrent mention of keywords such as "mesenchymal stem cells," "repair," and "platelet-rich plasma" throughout past two decades, highlighting their critical role in the evolution of the relevant field. This bibliometric analysis meticulously examines 758 publications, offering an in-depth exploration of the developments in tissue engineering and regenerative medicine for rotator cuff injuries between 2003 and 2023. The study effectively constructs a knowledge map, delineating the progressive contours of research in this domain. By pinpointing prevailing trends and emerging hotspots, the study furnishes crucial insights, setting a direction for forthcoming explorations and providing guidance for future researchers in this evolving field.

Autologous fat grafting is a common procedure in plastic, reconstructive, and aesthetic surgery. However, it is frequently associated with an unpredictable resorption rate of the graft depending on the engraftment kinetics. This, in turn, is determined by the interaction of the grafted adipose tissue with the tissue at the recipient site. Accordingly, preconditioning strategies have been developed following the principle of exposing these tissues in the pretransplantation phase to stimuli inducing endogenous protective and regenerative cellular adaptations, such as the upregulation of stress-response genes or the release of cytokines and growth factors. As summarized in the present review, these stimuli include hypoxia, dietary restriction, local mechanical stress, heat, and exposure to fractional carbon dioxide laser. Preclinical studies show that they promote cell viability, adipogenesis, and angiogenesis, while reducing inflammation, fibrosis, and cyst formation, resulting in a higher survival rate and quality of fat grafts in different experimental settings. Hence, preconditioning represents a promising approach to improve the outcome of fat grafting in future clinical practice. For this purpose, it is necessary to establish standardized preconditioning protocols for specific clinical applications that are efficient, safe, and easy to implement into routine procedures.

Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic tool in stem cell-based therapy due to their immunomodulatory or regenerative characteristics. Nowadays, controlled application of nonpathogenic bacterial cells and their derivatives has shown promise in preconditioning and manipulating MSC behavior. This approach is being explored in various fields, including immunotherapy, tissue engineering, and cell therapy. However, recent discoveries have elucidated the complex interactions between MSCs and microorganisms, especially bacteria and viruses, raising concerns regarding the utility of MSCs in clinical applications. In this review, we discussed the interactions between MSCs and microorganisms and highlighted both positive and negative aspects. We also examined the use of bacterial-derived compounds in MSCs-mediated interventions. The balanced colonization of the microbiome in organs, such as the oral cavity, not only does not hinder therapeutic interventions but also could be crucial for achieving desirable outcomes. On the contrary, disturbances in the microbiome have been found to disturb the biological potential of MSCs, such as migration, osteogenic differentiation, and cell proliferation. Evidence also suggests that commensal bacteria, following certain interventions, can transition to a pathogenic state when interacting with MSCs, leading to acute inflammation. Indeed, the maintenance of homeostasis through various approaches, such as probiotic application, results in an optimal equilibrium during MSCs-based therapies. However, further investigation into this matter is imperative to identify efficacious interventions.

Human decellularized adipose matrix (hDAM) has emerged as a promising, off-the-shelf option for soft tissue augmentation, providing a biocompatible scaffold that supports angiogenesis, adipogenesis, and volume retention with minimal immunogenicity. This systematic review synthesizes preclinical and clinical evidence on hDAM's regenerative potential, focusing on its capacity to integrate with host tissue and enhance volume retention. A comprehensive literature search was performed across multiple databases yielding 21 studies (14 preclinical, 6 clinical, and 1 combined) that met eligibility criteria. Risk of bias (RoB) was evaluated for animal and human studies using the Collaboration for the Assessment of Risks and Benefits of Anticancer Therapies (CAMARADES) and RoB In Nonrandomized Studies of Interventions (ROBINS-I) tools, respectively. Key preclinical findings indicate that hDAM supports progressive angiogenesis and adipogenesis, with significant weekly increases in vessel formation and adipocyte development. Linear mixed models were used to quantify these rates, showing an increase of 0.366% per week (p < 0.001) in the percentage of CD31+ positive area, and a 3.88% rise in perilipin-positive area per week (p < 0.001), representing angiogenesis and adipogenesis, respectively. Variability in regeneration rates underscores the influence of different hDAM preparation methods, such as enzyme-free decellularization and ultrasonication, which have been shown to improve cell compatibility and volume retention. Clinical studies demonstrate that hDAM achieves notable volume retention and patient satisfaction, particularly in facial and body contouring applications, while also improving skin texture, tone, and functionality. Compared with traditional autologous fat transfer and synthetic fillers, hDAM offers advantages in integration, resorption rates, and low complication risks, without donor site morbidity. Limitations of current studies include variability in hDAM preparation techniques, inconsistent outcome measures, and a paucity of long-term follow-up data. This review establishes hDAM as a safe and effective scaffold for soft tissue regeneration and provides a quantitative analysis of its regenerative timeline. Standardizing preparation methods and outcome measures, coupled with more randomized clinical trials, will be essential for optimizing treatment protocols. Future directions include exploring patient-specific factors and combination therapies to enhance hDAM's applicability in reconstructive and aesthetic surgery.

Tissue engineering, a crucial approach in medical research and clinical applications, aims to regenerate damaged organs. By combining stem cells, biochemical factors, and biomaterials, it encounters challenges in designing complex 3D structures. Artificial intelligence (AI) enhances tissue engineering through computational modeling, biomaterial design, cell culture optimization, and personalized medicine. This review explores AI applications in organ tissue engineering (bone, heart, nerve, skin, cartilage), employing various machine learning (ML) algorithms for data analysis, prediction, and optimization. Each section discusses common ML algorithms and specific applications, emphasizing the potential and challenges in advancing regenerative therapies.