Autologous cell membrane coatings on tissue engineering xenografts for suppression and alleviation of acute host immune responses

Recent advances in plant-derived polysaccharide scaffolds in tissue engineering: A review

As a natural three-dimensional biopolymer, decellularized plant-derived scaffolds usually comprise various polysaccharides, mostly cellulose, pectin, and hemicellulose. They are characterized by natural biocompatibility and porous structures. The emergence of decellularized purified polysaccharide scaffolds provides an attractive method to overcome the challenges associated with nutrient delivery and biocompatibility, as they serve as optimal non-immune environments for stem cell adhesion and proliferation. To date, limited corresponding literature is available to systemically summarize the development and potential of these scaffolds in tissue engineering. Therefore, the current review summarized the biomimetic properties of plant-derived polysaccharide scaffolds and the latest progress in tissue engineering applications. This review first discusses the advantages of decellularized plant-derived polysaccharide scaffolds by briefly introducing their features and current limitations in clinical applications. Subsequently, the latest progress in emerging applications of regenerative biomaterials is reviewed, followed by a discussion of the studies on the interactions of biomaterials with cells and tissues. Finally, challenges in obtaining reliable scaffolds and possible future directions are discussed.

Materials Strategies to Overcome the Foreign Body Response

The foreign body response (FBR) is an immune-mediated reaction that can occur with most biomaterials and biomedical devices. The FBR initiates a deterioration in the performance of implantable devices, representing a longstanding challenge that consistently hampers their optimal utilization. Over the last decade, significant strides are achieved based on either hydrogel design or surface modifications to mitigate the FBR. This review delves into recent material strategies aimed at mitigating the FBR. Further, the authors look forward to future novel anti-FBR materials from the perspective of clinical translation needs. Such prospective materials hold the potential to attenuate local immune responses, thereby significantly enhancing the overall performance of implantable devices.

Erythrocyte Membrane Coating Alleviate Immune Response and Promoted Adipogenesis in Adipose Matrix

Xenotransplantation of acellular adipose matrix (AAM) has come to prominence as an intriguing option for soft tissue reconstruction. However, the presence of immunogenic antigens within AAM can trigger unfavorable immune reactions, leading to inadequate in vivo regeneration outcomes. Therefore, the development of advanced technology capable of modulating immune responses is crucial for the therapeutic implementation of AAM xenografts. In this work, an innovative technique is created to bypass the immune system by covering the surface of both AAM and Arg-Gly-Asp (RGD) peptide-modified AAM xenografts with autologous red blood cell (RBC) membrane. The RBC membrane coating remained persistent and exhibited no significant decline even after 21 days. Moreover, it effectively reduced the expression of antigen major histocompatibility complex class 1 (MHC1) on the AAM surface. Following xenogeneic transplantation, the RBC-coated xenografts demonstrated increased expression of the adipogenic factor PPAR-γ, Adipoq, Fabp4, Fasn, and Plin1 and higher numbers of adipocytes. In addition, they exhibited decreased expression of immunological factors, including IL-6, IL-2, IFN-γ, and TNF-α, and fewer inflammatory cells. These findings indicate that RBC membrane coating successfully suppressed immune responses and promoted increased adipogenesis in AAM xenografts. Therefore, AAM camouflage coating with RBC has a lot of potential as a biomaterial for soft tissue reconstruction in clinical settings.

Harnessing Nanomedicine for Cartilage Repair: Design Considerations and Recent Advances in Biomaterials

Cartilage injuries are escalating worldwide, particularly in aging society. Given its limited self-healing ability, the repair and regeneration of damaged articular cartilage remain formidable challenges. To address this issue, nanomaterials are leveraged to achieve desirable repair outcomes by enhancing mechanical properties, optimizing drug loading and bioavailability, enabling site-specific and targeted delivery, and orchestrating cell activities at the nanoscale. This review presents a comprehensive survey of recent research in nanomedicine for cartilage repair, with a primary focus on biomaterial design considerations and recent advances. The review commences with an introductory overview of the intricate cartilage microenvironment and further delves into key biomaterial design parameters crucial for treating cartilage damage, including microstructure, surface charge, and active targeting. The focal point of this review lies in recent advances in nano drug delivery systems and nanotechnology-enabled 3D matrices for cartilage repair. We discuss the compositions and properties of these nanomaterials and elucidate how these materials impact the regeneration of damaged cartilage. This review underscores the pivotal role of nanotechnology in improving the efficacy of biomaterials utilized for the treatment of cartilage damage.

Rejuvenating Hyaline Cartilaginous Phenotype of Dedifferentiated Chondrocytes in Collagen II Scaffolds: A Mechanism Study Using Chondrocyte Membrane Nanoaggregates as Antagonists

Joint cartilage lesions affect the global population in the current aging society. Maintenance and rejuvenation of articular cartilage with hyaline phenotype remains a challenge as the underlying mechanism has not been completely understood. Here, we have designed and performed a mechanism study using scaffolds made of type II collagen (Col2) as the 3D cell cultural platforms, on some of which nanoaggregates comprising extracts of chondrocyte membrane (CCM) were coated as the antagonist of Col2. Dedifferentiated chondrocytes were, respectively, seeded into these Col2 based scaffolds with (antCol2S) or without (Col2S) CCM coating. After 6 weeks, in Col2S, the chondrocytes were rejuvenated to regain hyaline phenotype, whereas this redifferentiation effect was attenuated in antCol2S. Transcriptomic and proteomic profiling indicated that the Wnt/β-catenin signaling pathway, which is an opponent to maintenance of the hyaline cartilaginous phenotype, was inhibited in Col2S, but it was contrarily upregulated in antCol2S due to the antagonism and shielding against Col2 by the CCM coating. Specifically, in antCol2S, since the coated CCM nanoaggregates contain the same components as those present on the surface of the seeded chondrocytes, the corresponding ligand sites on Col2 had been preoccupied and saturated by CCM coating before exposure to the seeded cells. The results indicated that the ligation between Col2 ligands and integrin α5 receptors on the surface of the seeded chondrocytes in antCol2S was antagonized by the CCM coating, which facilitates the Wnt/β-catenin signaling toward the loss of hyaline cartilaginous phenotype. This finding reveals the contribution of Col2 for maintenance and rejuvenation of the hyaline cartilaginous phenotype in chondrocytes.

An engineered lymph node comprising porous collagen scaffold with hybridized biological signals embedded in B cell membrane coatings

Complications can arise from damaging or removing lymph nodes after surgeries for malignant tumours. Our team has developed an innovative solution to recreate lymph nodes via an engineering approach. Using a Type II collagen scaffold coated with B cell membranes for the sake of attracting T cells in different regions, we could mimic the thymus-dependent and thymus-independent areas in vitro. This engineering strategy based on biophysical mimicry has a great potential for clinical applications. By further conjugating biological signals, anti-CD3/28, onto the scaffold coated with the B cell membrane, we achieved an 11.6-fold expansion of T cells within 14 days of in vitro culture while ensuring their activity, phenotype homeostasis, and differentiation capacity kept intact. Artificial lymph nodes had excellent biocompatibility and caused no pathological or physiological adverse effects after implantation into C57BL6 mice. In vivo assays also demonstrated that this artificial lymph node system positively adhered to omental tissues, creating an environment that fostered T cell growth and prevented cellular failure and death. Additionally, it induced vascular and lymphatic vessel invasion, which was beneficial to the migration and circulation of T cells between this system and peripheral blood. Due to the porous collagen fibre structure, it also facilitated the infiltration of host immune cells. This work opens new avenues to immune organ regeneration via a tissue engineering approach.

Current status and development direction of immunomodulatory therapy for intervertebral disk degeneration

Intervertebral disk (IVD) degeneration (IVDD) is a main factor in lower back pain, and immunomodulation plays a vital role in disease progression. The IVD is an immune privileged organ, and immunosuppressive molecules in tissues reduce immune cell (mainly monocytes/macrophages and mast cells) infiltration, and these cells can release proinflammatory cytokines and chemokines, disrupting the IVD microenvironment and leading to disease progression. Improving the inflammatory microenvironment in the IVD through immunomodulation during IVDD may be a promising therapeutic strategy. This article reviews the normal physiology of the IVD and its degenerative mechanisms, focusing on IVDD-related immunomodulation, including innate immune responses involving Toll-like receptors, NOD-like receptors and the complement system and adaptive immune responses that regulate cellular and humoral immunity, as well as IVDD-associated immunomodulatory therapies, which mainly include mesenchymal stem cell therapies, small molecule therapies, growth factor therapies, scaffolds, and gene therapy, to provide new strategies for the treatment of IVDD.

Toward Artificial Cell-Mediated Tissue Engineering: A New Perspective

The fast-growing pace of regenerative medicine research has allowed the development of a range of novel approaches to tissue engineering applications. Until recently, the main points of interest in the majority of studies have been to combine different materials to control cellular behavior and use different techniques to optimize tissue formation, from 3-D bioprinting to in situ regeneration. However, with the increase of the understanding of the fundamentals of cellular organization, tissue development, and regeneration, has also come the realization that for the next step in tissue engineering, a higher level of spatiotemporal control on cell-matrix interactions is required. It is proposed that the combination of artificial cell research with tissue engineering could provide a route toward control over complex tissue development. By equipping artificial cells with the underlying mechanisms of cellular functions, such as communication mechanisms, migration behavior, or the coherent behavior of cells depending on the surrounding matrix properties, they can be applied in instructing native cells into desired differentiation behavior at a resolution not to be attained with traditional matrix materials.

Advances in lung bioengineering: Where we are, where we need to go, and how to get there

Lung transplantation is the only potentially curative treatment for end-stage lung failure and successfully improves both long-term survival and quality of life. However, lung transplantation is limited by the shortage of suitable donor lungs. This discrepancy in organ supply and demand has prompted researchers to seek alternative therapies for end-stage lung failure. Tissue engineering (bioengineering) organs has become an attractive and promising avenue of research, allowing for the customized production of organs on demand, with potentially perfect biocompatibility. While breakthroughs in tissue engineering have shown feasibility in practice, they have also uncovered challenges in solid organ applications due to the need not only for structural support, but also vascular membrane integrity and gas exchange. This requires a complex engineered interaction of multiple cell types in precise anatomical locations. In this article, we discuss the process of creating bioengineered lungs and the challenges inherent therein. We summarize the relevant literature for selecting appropriate lung scaffolds, creating decellularization protocols, and using bioreactors. The development of completely artificial lung substitutes will also be reviewed. Lastly, we describe the state of current research, as well as future studies required for bioengineered lungs to become a realistic therapeutic modality for end-stage lung disease. Applications of bioengineering may allow for earlier intervention in end-stage lung disease and have the potential to not only halt organ failure, but also significantly reverse disease progression.

Red blood cell membrane-functionalized Nanofibrous tubes for small-diameter vascular grafts

The off-the-shelf small-diameter vascular grafts (SDVGs) have inferior clinical efficacy. Red blood cell membrane (Rm) has easy availability and multiple bioactive components (such as phospholipids, proteins, and glycoproteins), which can improve the clinic's availability and patency of SDVGs. Here we developed a facile approach to preparing an Rm-functionalized poly-ε-caprolactone/poly-d-lysine (Rm@PCL/PDL) tube by co-incubation and single-step rolling. The integrity, stability, and bioactivity of Rm on Rm@PCL/PDL were evaluated. The revascularization of Rm@PCL/PDL tubes was studied by implantation in the carotid artery of rabbits. Rm@PCL/PDL can be quickly prepared and showed excellent bioactivity with good hemocompatibility and great anti-inflammatory. Rm@PCL/PDL tubes as the substitute for the carotid artery of rabbits had good patency and quick remodeling within 21 days. Rm, as a "self" biomaterial with high biosafety, provides a new and facile approach to developing personalized or universal SDVGs for the clinic, which is of great significance in cardiovascular regenerative medicine and organ chip.

Enhanced biocompatibility of silk sericin/caffeic acid nanoparticles by red blood cell membranes cloaking

Caffeic acid (CA) is an antioxidant phenolic compound that enriched in coffee beans, however, its administration often restrains by the instability and low solubility. Nanoparticle encapsulation is an effective approach to improve the therapeutic activity of CA. For example, silk sericin (SS), a natural biomaterial finds applications in food, cosmetics and biomedical fields, is proved here to be an appropriate encapsulation agent for CA, and a SS/CA composite nanoparticle has been fabricated. To further improve the biocompatibility of SS/CA, a red blood cell membranes (RM) cloaking strategy is adopted. The as-formed SS/CA/RM preserves the antioxidant activity of CA, and shows satisfactory biocompatibility especially under high concentration. Hope this can provide a potential appropriative strategy to adjust the chemical stability of insoluble drugs and to improve their biocompatibility.

Decellularized Extracellular Matrix-Based Bioinks for Tendon Regeneration in Three-Dimensional Bioprinting

In the last few years, attempts to improve the regeneration of damaged tendons have been rising due to the growing demand. However, current treatments to restore the original performance of the tissue focus on the usage of grafts; although, actual grafts are deficient because they often cannot provide enough support for tissue regeneration, leading to additional complications. The beneficial effect of combining 3D bioprinting and dECM as a novel bioink biomaterial has recently been described. Tendon dECMs have been obtained by using either chemical, biological, or/and physical treatments. Although decellularization protocols are not yet standardized, recently, different protocols have been published. New therapeutic approaches embrace the use of dECM in bioinks for 3D bioprinting, as it has shown promising results in mimicking the composition and the structure of the tissue. However, major obstacles include the poor structural integrity and slow gelation properties of dECM bioinks. Moreover, printing parameters such as speed and temperature have to be optimized for each dECM bioink. Here, we show that dECM bioink for 3D bioprinting provides a promising approach for tendon regeneration for future clinical applications.

Subchondral bone-inspired hydrogel scaffold for cartilage regeneration

Promoting the in situ regeneration of cartilage without additional cells or cytokines remains challenging. Here, inspired by the unique microstructures of subchondral bone, a cell and cytokine free hydrogel scaffold for cartilage regeneration was developed via a strategy of directional lyophilization and postcrosslinking. This strategy achieved intersecting microchannels in an orderly arrangement and an aligned ladder-like texture in a semi-interpenetrating hydrogel network. The resulting hydrogel had similar mechanical properties to the native cartilage extracellular matrix. Incorporating chitosan into the rigid network also endowed the hydrogel with excellent hemostatic properties. By delicately tuning the components and postcrosslinking conditions, the hydrogel was further endowed with suitable swelling and degradation properties for cartilage regeneration. In vitro tests showed that the highly biocompatible hydrogel scaffold could facilitate the migration and chondrogenic differentiation of bone marrow mesenchymal stem cells. In vivo results further verified that the hydrogel could promote the in situ regeneration of cartilage in a rat model of osteochondral defects. In summary, the subchondral bone-like hydrogel revealed promising prospects in cartilage regeneration and a variety of bioremediation applications.

Stem Cell Membrane-Encapsulated Zeolitic Imidazolate Framework-8: A Targeted Nano-Platform for Osteogenic Differentiation

Mesenchymal stem cells (MSCs) have been recognized as one of the most promising pharmaceutical multipotent cells, and a key step for their wide application is to safely and efficiently regulate their activities. Various methods have been proposed to regulate the directional differentiation of MSCs during tissue regeneration, such as nanoparticles and metal ions. Herein, nanoscale zeolitic imidazolate framework-8 (ZIF-8), a Zn-based metal-organic framework, is modified to direct MSCs toward an osteoblast lineage. Specifically, ZIF-8 nanoparticles are encapsulated using stem cell membranes (SCMs) to mimic natural molecules and improve the biocompatibility and targeted ability toward MSCs. SCM/ZIF-8 nanoparticles adjust the sustained release of Zn²⁺ , and promote their specific internalization toward MSCs. The internalized SCM/ZIF-8 nanoparticles show excellent biocompatibility, and increase MSCs' osteogenic potentials. Moreover, RNA-sequencing results elucidate that the activated cyclic adenosine 3,5-monophosphate (cAMP)-PKA-CREB signaling pathway can be dominant in accelerating osteogenic differentiation. In vivo, SCM/ZIF-8 nanoparticles greatly promote the formation of new bone tissue in the femoral bone defect detected by 3D micro-CT, hematoxylin and eosin staining, and Masson staining after 4 weeks. Overall, the SCM-derived ZIF-8 nanostructures achieve the superior targeting ability, biocompatibility, and enhanced osteogenesis, providing a constructive design for tissue repair.

A Biomaterial-Based Hedging Immune Strategy for Scarless Tendon Healing

Scarring rather than regeneration, is an inevitable outcome of unbalanced amplifications of inflammation-destructive signals and atresia of the regenerative niche. However, identifying and effectively hedging against the risk of scarring and realizing the conversion of regenerative cues remain difficult. In this work, a hedging immune strategy based microfibrous membrane (Him-MFM), by tethering distearoyl phosphoethanolamine layer-supported copoly(lactic/glycolic acid) electrospun fibers with identified CD11b⁺ /CD68⁺ scarring subpopulation membranes in the immune landscape after tendon injury to counterweigh tissue damage, is reported. Him-MFM, carrying relevant risk receptors is shown to shift high type I biased polarization, alleviate apoptosis and metabolic stress, and mitigate inflammatory tenocyte response. Remarkably, the hedging immune strategy reverses the damaged tendon sheath barrier to the innate IL-33 secretory phenotype by 4.36 times and initiates the mucous-IL-33-Th2 axis, directly supplying a transient but obligate regenerative niche for sheath stem cell proliferation. In murine flexor tendon injury, the wrapping of Him-MFM alleviates pathological responses, protects tenocytes in situ, and restores hierarchically arranged collagen fibers covered with basement membrane, and is structurally and functionally comparable to mature tendons, demonstrating that the hedging immunity is a promising strategy to yield regenerative responses not scarring.

Scaffold-free approaches for the fabrication of engineered articular cartilage tissue

Tissue engineered cartilaginous constructs have meet great advances in the past decades as a treatment for osteoarthritis, a degenerative disease affecting people all over the world as the population ages. Scaffold-free tissue engineered constructs are designed and developed in recent years with only cells and cell-derived matrix involved. Scaffold-free tissue constructs do not require cell adherence on exogenous materials and are superior to scaffold-based constructs in (1) relying on only cells to produce matrix, (2) not interfering cell-cell signaling, cell migration or small molecules diffusion after implantation and (3) introducing no exogenous impurities. In this review, three main scaffold-free methodologies for cartilage tissue engineering, the cell sheet technology, the phase transfer cell culture-living hyaline cartilage graft (PTCC-LhCG) system and the cell aggregate-based (bottom-up) methods, were reviewed, covering mold fabrication, decellularization and 3D bioprinting. The recent advances, medical applications, superiority and drawbacks were elaborated in detail.

3D-printed microneedles with open groove channels for liquid extraction

Microneedles (MNs) offer a simple and minimally invasive way to sample skin interstitial fluid for bioanalysis. Through the integration with portable or wearable sensing devices, it allows us to get qualitative information about some biomarkers in situ. This work is to show a MN platform with open groove channels that are manufactured using photopolymerization 3D printing. The grooves on the needle surface permit that liquid flows from the tips to the base under the influence of capillary force. The ultimate MN device can penetrate skin and tissues and sample liquid in the skin model. By taking the glucose as the model biomarker, we demonstrate that the biomarkers in the extracted liquid can be analyzed in situ by the commercial test strips attached to the back.

Cell-derived extracellular vesicles and membranes for tissue repair

Humans have a limited postinjury regenerative ability. Therefore, cell-derived biomaterials have long been utilized for tissue repair. Cells with multipotent differentiation potential, such as stem cells, have been administered to patients for the treatment of various diseases. Researchers expected that these cells would mediate tissue repair and regeneration through their multipotency. However, increasing evidence has suggested that in most stem cell therapies, the paracrine effect but not cell differentiation or regeneration is the major driving force of tissue repair. Additionally, ethical and safety problems have limited the application of stem cell therapies. Therefore, nonliving cell-derived techniques such as extracellular vesicle (EV) therapy and cell membrane-based therapy to fulfil the unmet demand for tissue repair are important. Nonliving cell-derived biomaterials are safer and more controllable, and their efficacy is easier to enhance through bioengineering approaches. Here, we described the development and evolution from cell therapy to EV therapy and cell membrane-based therapy for tissue repair. Furthermore, the latest advances in nonliving cell-derived therapies empowered by advanced engineering techniques are emphatically reviewed, and their potential and challenges in the future are discussed.

Multifunctional Biomedical Materials Derived from Biological Membranes

The delicate structure and fantastic functions of biological membranes are the successful evolutionary results of a long-term natural selection process. Their excellent biocompatibility and biofunctionality are widely utilized to construct multifunctional biomedical materials mainly by directly camouflaging materials with single or mixed biological membranes, decorating or incorporating materials with membrane-derived vesicles (e.g., exosomes), and designing multifunctional materials with the structure/functions of biological membranes. Here, the structure-function relationship of some important biological membranes and biomimetic membranes are discussed, such as various cell membranes, extracellular vesicles, and membranes from bacteria and organelles. Selected literature examples of multifunctional biomaterials derived from biological membranes for biomedical applications, such as drug- and gene-delivery systems, tissue-repair scaffolds, bioimaging, biosensors, and biological detection, are also highlighted. These designed materials show excellent properties, such as long circulation time, disease-targeted therapy, excellent biocompatibility, and selective recognition. Finally, perspectives and challenges associated with the clinical applications of biological-membrane-derived materials are discussed.

Demineralized and decellularized bone extracellular matrix-incorporated electrospun nanofibrous scaffold for bone regeneration

Extracellular matrix (ECM)-based materials have been employed as scaffolds for bone tissue engineering, providing a suitable microenvironment with biophysical and biochemical cues for cell attachment, proliferation and differentiation. In this study, bone-derived ECM (bECM)-incorporated electrospun poly(ε-caprolactone) (PCL) (bECM/PCL) nanofibrous scaffolds were prepared and their effects on osteogenesis were evaluated in vitro and in vivo. The results showed that the bECM/PCL scaffolds promoted the attachment, spreading, proliferation and osteogenic differentiation of rat mesenchymal stem cells (MSCs), mitigated the foreign-body reaction, and facilitated bone regeneration in a rat calvarial critical size defect model. Thus, this study suggests that bECM can provide a promising option for bone regeneration.

Magnetic resonance imaging for non-invasive clinical evaluation of normal and regenerated cartilage

With the development of tissue engineering and regenerative medicine, it is much desired to establish bioimaging techniques to monitor the real-time regeneration efficacy in vivo in a non-invasive way. Herein, we tried magnetic resonance imaging (MRI) to evaluate knee cartilage regeneration after implanting a biomaterial scaffold seeded with chondrocytes, namely, matrix-induced autologous chondrocyte implantation (MACI). After summary of the T2 mapping and the T1-related delayed gadolinium-enhanced MRI imaging of cartilage (dGEMRIC) in vitro and in vivo in the literature, these two MRI techniques were tried clinically. In this study, 18 patients were followed up for 1 year. It was found that there was a significant difference between the regeneration site and the neighboring normal site (control), and the difference gradually diminished with regeneration time up to 1 year according to both the quantitative T1 and T2 MRI methods. We further established the correlation between the quantitative evaluation of MRI and the clinical Lysholm scores for the first time. Hence, the MRI technique was confirmed to be a feasible semi-quantitative yet non-invasive way to evaluate the in vivo regeneration of knee articular cartilage.

Decellularized scaffold and its elicited immune response towards the host: the underlying mechanism and means of immunomodulatory modification

The immune response of the host towards a decellularized scaffold is complex. Not only can a number of immune cells influence this process, but also the characteristics, preparation and modification of the decellularized scaffold can significantly impact this reaction. Such factors can, together or alone, trigger immune cells to polarize towards either a pro-healing or pro-inflammatory direction. In this article, we have comprehensively reviewed factors which may influence the immune response of the host towards a decellularized scaffold, including the source of the biomaterial, biophysical properties or modifications of the scaffolds with bioactive peptides, drugs and cytokines. Furthermore, the underlying mechanism has also been recapitulated.

Tissue Engineering for Mimics and Modulations of Immune Functions

In the field of regenerative medicine, advances in tissue engineering have surpassed the reconstruction of individual tissues or organs and begun to work towards engineering systemic factors such as immune objects and functions. The immune system plays a crucial role in protecting and regulating systemic functions in the human body. Engineered immune tissues and organs have shown potential in recovering dysfunctions and aplasia of the immune system and the evasion from immune-mediated inflammatory responses and rejection elicited by engineered implants from allogeneic or xenogeneic sources are also being pursued to facilitate clinical transplantation of tissue engineered grafts. Here, current progress in tissue engineering to mimic or modulate immune functions is reviewed and elaborated from two perspectives: 1) engineering of immune tissues and organs per se and 2) immune evasion of host immunoinflammatory rejection by tissue-engineered implants.

Improvement of ECM-based bioroot regeneration via N-acetylcysteine-induced antioxidative effects

BACKGROUND

The low survival rate or dysfunction of extracellular matrix (ECM)-based engineered organs caused by the adverse effects of unfavourable local microenvironments on seed cell viability and stemness, especially the effects of excessive reactive oxygen species (ROS), prompted us to examine the importance of controlling oxidative damage for tissue transplantation and regeneration. We sought to improve the tolerance of seed cells to the transplant microenvironment via antioxidant pathways, thus promoting transplant efficiency and achieving better tissue regeneration.

METHODS

We improved the antioxidative properties of ECM-based bioroots with higher glutathione contents in dental follicle stem cells (DFCs) by pretreating cells or loading scaffolds with the antioxidant NAC. Additionally, we developed an in situ rat alveolar fossa implantation model to evaluate the long-term therapeutic effects of NAC in bioroot transplantation.

RESULTS

The results showed that NAC decreased H₂O₂-induced cellular damage and maintained the differentiation potential of DFCs. The transplantation experiments further verified that NAC protected the biological properties of DFCs by repressing replacement resorption or ankylosis, thus facilitating bioroot regeneration.

CONCLUSIONS

The following findings suggest that NAC could significantly protect stem cell viability and stemness during oxidative stress and exert better and prolonged effects in bioroot intragrafts.