Tissue engineering. Part C, Methods最新文献

Hepatocellular carcinoma (HCC) is an aggressive liver tumor with a unique metabolic profile and a shift to glycolytic metabolism. This review discusses the contribution of pyruvate kinase M2 (PKM2) to HCC development and its potential as a target for therapy. We carried out a broad literature review on PKM2, focusing on its role in the glycolytic pathway and special interactions with key signaling pathways like Phosphoinositide 3-kinase/Protein kinase B/Mammalian target of rapamycin (PI3K/AKT/mTOR) and Mitogen-activated protein kinase (MAPK). PKM2 also performs a dual role in energy metabolism and signal transduction in HCC. PKM2 is paramount in the induction of HCC by regulating cellular metabolism and oncogenic signaling pathways. It promotes tumor growth, survival, and metastasis through interaction with the PI3K/AKT/mTOR and MAPK pathways. PKM2 is a key factor in HCC pathogenesis, with a dual impact on metabolism and signaling. Its properties may open the way for developing novel therapeutic interventions against HCC. Thus, PKM2 inhibition may offer further opportunities for tumor growth blockade, which could meaningfully improve patients' clinical outcomes.

Sympathetic innervation plays a critical role in regulating vascular function, yet its influence on vascular regeneration and reinnervation following ischemic injury remains poorly understood. This study develops and validates murine models of localized sympathetic denervation using 6-hydroxydopamine (6-OHDA) to enable study of the sympathetic nervous system's impact on vascular systems during tissue repair. Two methods of 6-OHDA administration were employed: a single topical application during open surgery and minimally invasive weekly subcutaneous injections. The topical application model achieved temporary denervation lasting 1 week without causing vascular damage, while the subcutaneous injection model provided sustained denervation for up to 4 weeks with minimal inflammation and no significant changes to vascular architecture. To investigate the effects of denervation in an ischemic context, these models were combined with a hindlimb ischemia model. Ischemia induced persistent denervation in both 6-OHDA-treated and control limbs, with limited sympathetic nerve regeneration observed over 4 weeks. Despite persistent denervation, microvascular density and perfusion recovery in ischemic muscles were comparable between denervated and control groups. This suggests that ischemia governs vascular regeneration independently of sympathetic input. These results demonstrate that localized 6-OHDA administration provides a versatile tool for achieving controlled sympathetic denervation in peripheral arteries. These models provide a novel platform for studying vascular regeneration and reinnervation under both normal and ischemic conditions, offering novel insights into the interactions between neural regulation and vascular repair processes. This work lays the foundation for future research into neural-vascular crosstalk and new possibilities for developing regenerative therapies targeting the autonomic regulation of vascular health.

In vitro experiments, a crucial component of preclinical research, are widely used due to their accessibility and controlled conditions. However, traditional two-dimensional (2D) cell models are limited in their ability to simulate the complex interactions in organ systems. To address it, emerging technologies have shifted cell cultures from 2D to three-dimensional (3D), offering improved in vitro-in vivo correlation for traditional in vitro screening. Reconstructed human epidermis (RHE) is a 3D skin tissue model that closely mimics human skin in both structure and function. We established a sodium dodecyl sulfate (SDS)-induced epidermal injury model on RHE, and the result demonstrated that treating RHE with a 2.5 mg/mL SDS solution for 24 h could cause a significant epidermal damage. We also treated it with common clinical repair biomaterials, to screen the key indicator of SDS-induced 3D epidermal injury model, which includes several chemokines such as regulated upon activation normal T-cell expressed and secreted and interferon-γ-induced protein 10 that triggered inflammatory responses, and the important component protein of barrier structure-filaggrin and loricrin. In this study, we provide a platform for biomaterials evaluation that offers support and complementarities for in vitro experiments of skin repair.

Nanozymes, as innovative enzyme mimics, hold significant promise for wound care, including antibacterial properties and tissue regeneration. Given their potential to transform wound management, this study utilizes advanced bibliometric tools to provide a comprehensive analysis of the nanozyme research landscape. The analysis covers various aspects, including publication trends, institutional contributions, journal coverage, and author involvement, offering a holistic view of research dynamics. It reveals the evolution of nanozyme research across different phases of wound healing by examining keyword co-occurrence frequencies and timeline developments. In addition, the study identifies emerging research clusters within these phases, focusing on three key areas: enhancing nanozyme performance, integrating them with hydrogel matrices, and developing responsiveness to external stimuli. These clusters highlight the increasing sophistication and diversity of nanozyme-based solutions for wound care. Furthermore, the study explores the intersection of nanozyme research with artificial intelligence (AI) and wearable sensors. This integration presents unprecedented opportunities for real-time monitoring, personalized treatment plans, and predictive analytics in wound care. The findings indicate a growing interest in this interdisciplinary field, pinpointing research frontiers centered around AI-driven wound assessment, continuous monitoring through wearable technologies, and the application of AI algorithms in nanozyme-based wound dressings. In summary, this bibliometric study provides a comprehensive global overview of research trends, key literature, hotspots, and emerging frontiers in nanozyme-based wound care. By investigating the synergy between AI, wearable sensors, and nanozymes, it elucidates the potential for novel and personalized treatment strategies in this rapidly advancing field.

Mouse embryonic fibroblasts (MEFs) have been widely used as feeder cells in embryonic stem cell cultures because they can mimic the embryonic microenvironment. Milk fat globule-epidermal growth factor 8 (MFGE8) is expressed during mouse gonadal development, 10.5-13.5 embryonic, and is also found in MEF-conditioned medium (MEF-CM). Feeder-less culture of human-induced pluripotent stem cells (iPSCs) with MEF-CM significantly decreased the number of adherent cells when an inhibitory antibody against MFGE8 was used. The concentration of mouse MFGE8 in MEF-CM, as measured by an ELISA (Enzyme-Linked Immunosorbent Assay), was 0.16-1.24 μg/mL. Mouse MFGE8 and human MFGE8 have partially different molecular structures. Both the recombinant mouse MFGE8 and human MFGE8 significantly promoted cell adhesion of human iPSCs at medium-added concentrations of 2 μg/mL. This cell adhesion was also strongly inhibited by Arginylglycylaspartic acid (RGD) inhibitors, suggesting that it is dependent on the RGD sequence. The integrin αVβ5 expressed in iPSCs was thought to be involved in binding to the RGD sequence. MEF-CMs have long been an essential bio-derived material for the feeder culture method of iPSC culture. This study demonstrates that MFGE8 in MEF-CM is a functional factor in the promoting of cell adhesion of human iPSCs. Furthermore, the use of MFGE8-containing media demonstrates that iPSCs can be established and cultured while maintaining pluripotency and inducing three germ layer differentiation. The results of this study suggest the possibility of using MFGE8 as a scaffold material suitable for inducing differentiation when reproducing in vivo maturation in vitro.

Developing effective drug screening methods for type 2 diabetes requires physiologically relevant models. Traditional 2D cell cultures have limitations in replicating in vivo conditions, leading to challenges in assessing drug efficacy. To overcome these issues, we developed a 3D artificial muscle model that induces insulin resistance, a hallmark of type 2 diabetes. Using C2C12 myoblasts cultured in a scaffold of 1% alginate and 1 mg/mL collagen type 1, we optimized conditions for differentiation and structural stability. Insulin resistance was induced using palmitic acid (PA), and glucose uptake was assessed using the fluorescent glucose analog 2-NBDG. The 3D model demonstrated superior glucose uptake responses compared with 2D cultures, with a threefold increase in insulin-stimulated glucose uptake on days 4 and 8 of differentiation. Induced insulin resistance was observed with 0.1 mM PA, which maintained cell viability and differentiation capacity. The model was validated through comparative drug screening using rosiglitazone and metformin, as well as 165 candidate compounds provided by Korea Chemical Bank. Drug screening revealed that three out of five hit compounds identified in both 2D and 3D models exhibited greater efficacy in 3D cultures, with results consistent with ex vivo assays using mouse soleus muscle. This model closely mimics in vivo conditions, offering a robust platform for type 2 diabetes drug discovery while supporting ethical research practices.

Scaffold-free tissue engineering strategies using cellular aggregates, microtissues, or organoids as "biological building blocks" could potentially be used for the engineering of scaled-up articular cartilage or endochondral bone-forming grafts. Such approaches require large numbers of cells; however, little is known about how different chondrogenic growth factor stimulation regimes during cellular expansion and differentiation influence the capacity of cellular aggregates or microtissues to fuse and generate hyaline cartilage. In this study, human bone marrow mesenchymal stem/stromal cells (MSCs) were additionally stimulated with bone morphogenetic protein 2 (BMP-2) and/or transforming growth factor (TGF)-β1 during both monolayer expansion and subsequent chondrogenic differentiation in a microtissue format. MSCs displayed a higher proliferative potential when expanded in the presence of TGF-β1 or TGF-β1 and BMP-2. Next, the chondrogenic potential of these human MSCs was explored in a medium-high throughput microtissue system. After 3 weeks of culture, MSCs stimulated with BMP-2 during expansion and differentiation deposited higher levels of glycosaminoglycans (GAGs) and collagen, while staining negative for calcium deposits. The fusion capacity of the microtissues was not impacted by these different growth factor stimulation regimes. After 3 weeks of fusion, it was observed that MSCs stimulated with TGF-β1 during expansion and additionally with BMP-2 during chondrogenic differentiation deposited the highest levels of sulfated GAGs. No increase in type X collagen deposition was observed with additional growth factor stimulation. This study demonstrates the importance of carefully optimizing MSC expansion and differentiation conditions when developing modular tissue engineering strategies (e.g., cellular aggregates and microtissues) for cartilage tissue engineering applications.

Plant-derived hydrocolloids offer promising prospects in biomedical applications. Among these, Flaxseed hydrocolloid (FSH) can form a soft, elastic, and biocompatible hydrocolloid with tunable viscosity and superior swelling capacity, making it an attractive scaffold. This study introduces a green extraction method for FSH, employing a single-step aqueous extraction process and fabrication of FSH scaffold. Despite growing interest, the pristine form of FSH has not been investigated for sustainable long-term three-dimensional (3D) cell culture. Here, FSH scaffolds were thoroughly characterized for their morphological, chemical, mechanical, and biological properties. 3D cell culture experiments were conducted using NIH-3T3 mouse fibroblast cells, and cell viability was assessed using live/dead and Alamar Blue assays. High cell viability was sustained for long term compared with 2D cell culture. Cell adhesion and 3D cellular morphology on FSH scaffold for 30 days were monitored by scanning electron microscopy analysis. Also, collagen type-I and F-actin expressions were analyzed by immunostaining after 30 days of culture, resulting in 5- and 4-fold increments of fluorescence intensity, respectively. Results indicate sustained cell viability in the long term and favorable cell-material interaction, demonstrating the potential of FSH as a scaffold. This study emphasizes the importance of the green extraction approach, improving the biocompatibility and functionality of FSH tissue engineering applications.

As society advances, an increasing number of people are focusing on the antiaging process of the body and seeking ways to maintain youthful facial features. Intradermal injection has been used to effectively improve the rough and wrinkled skin, playing a role in skin rejuvenation. However, the main component of intradermal injection products is cross-linked sodium hyaluronate (SHA), which has biological toxicity and potential carcinogenicity. In this study, amino acids were used as hyaluronidase inhibitors and combined with non-cross-linked SHA to prepare a synergically stable SHA composite hydrogel. The effects of amino acids on the viscosity and enzyme activity of the hydrogel were investigated. To determine the stability and antioxidant properties of the composite hydrogel, the effects of the introduction of stabilizer and antioxidant on the hydrogel properties were systematically studied. The results of the in vitro study showed that the introduction of amino acids effectively reduced the activity of hyaluronidase, addressing the problem of rapid hydrolysis and the short half-life of SHA hydrogel in vivo. In addition, the results revealed that NaCl stabilizer, niacinamide, and vitamin B12 antioxidants effectively maintained the stability and antioxidant properties of the hydrogels. In vivo results showed that SHA composite hydrogels had no irritating effect on the skin, and the subcutaneous experiments of mice showed that SHA composite hydrogel still retained a high content after 4 weeks. Therefore, the SHA composite hydrogels have promising applications in the field of medical cosmetology.

The failure of orthopedic implants can significantly impact patients physiologically, psychologically, and economically. A bibliometric study of the field of surface modification for antimicrobial purposes in orthopedic implants provides insights into its developmental trajectory and offers valuable predictions for future advancements, thus playing a pivotal role in guiding research in this domain. Relevant publications on surface modification for antimicrobial purposes in orthopedic implants published between 2014 and 2024 were selected from the Web of Science (Core Collection) dataset and analyzed using VOSviewer and Citespace. The analysis encompassed 725 articles. Over the past decade, there has been a steady increase in the number of publications related to surface modification for antimicrobial purposes in orthopedic implants, with China emerging as the primary contributor. Novel antimicrobial materials development, osteogenesis, and angiogenesis have become focal areas of research interest in this domain. Surface modification for antimicrobial purposes in orthopedic implants garners increasing attention. Research in this field is anticipated to expand, with future focus likely to revolve around novel material applications, repair outcomes, and underlying mechanisms.