Tissue Engineering. Part B, Reviews最新文献

Tissue and organ dysfunction are major causes of worldwide morbidity and mortality with all medical specialties being impacted. Tissue engineering is an interdisciplinary field relying on the combination of scaffolds, cells, and biologically active molecules to restore form and function. However, clinical translation is still largely hampered by limitations in vascularization. Consequently, a thorough understanding of the microvasculature is warranted. This review provides an overview of (1) angiogenesis, including sprouting angiogenesis, intussusceptive angiogenesis, vascular remodeling, vascular co-option, and inosculation; (2) strategies for vascularized engineered tissue fabrication such as scaffold modulation, prevascularization, growth factor utilization, and cell-based approaches; (3) guided microvascular development via scaffold modulation with electromechanical cues, 3D bioprinting, and electrospinning; (4) surgical approaches to bridge the micro- and macrovasculatures in order to hasten perfusion; and (5) building specific vasculature in the context of tissue repair and organ transplantation, including skin, adipose, bone, liver, kidney, and lung. Our goal is to provide the reader with a translational overview that spans developmental biology, tissue engineering, and clinical surgery.

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.

Vascular surgery is facing a critical demand for novel vascular grafts that are biocompatible and thromboresistant. This urgency is particularly applicable to bypass operations involving small caliber vessels. In the realm of tissue engineering, the development of fully vascularized organs is promising as a solution to organ shortage for transplantation. To achieve this, it is essential to (re)construct a biocompatible and nonthrombogenic vascular network within these organs. In this systematic review, we identify, classify, and discuss basic principles and methods used to perform in vitro/ex vivo dynamic thrombogenicity testing of perfusable tissue-engineered organs and tissues. We conducted a preregistered systematic review of studies published in the last 23 years according to PRISMA-P Guidelines. This comprised a systematic data extraction, in-depth analysis, and risk of bias assessment of 116 included studies. We identified shaking (n = 28), flow loop (n = 17), ex vivo (arteriovenous shunt, n = 33), and dynamic in vitro models (n = 38) as the main approaches for thrombogenicity assessment. This comprehensive review reveals a prevalent lack of standardization and provides a valuable guide in the design of standardized experimental setups.

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.

The healing process after tendon injury is often accompanied by the formation of peritendinous adhesion, contributing to limb dysfunction and exerting detrimental effects on the individuals, as well as the development of society and economy. With the continuous development of material science, as well as the augmented understanding of tendon healing and the mechanism of peritendinous adhesion formation, materials used for the fabrication of barrier membranes against peritendinous adhesion emerge endlessly. In this article, based on the analysis of the mechanism of adhesion formation, we first review the commonly used natural and synthetic materials, along with their corresponding fabrication strategies, in order to furnish valuable insights for the future optimization and development of antiperitendinous adhesion barrier membranes. This article also discusses the interaction between antiadhesion materials and cells for ameliorating peritendinous adhesion.