High yield engineered nanovesicles from ADSC with enriched miR-21-5p promote angiogenesis in adipose tissue regeneration

Endoscopic nasal delivery of engineered endothelial progenitor cell-derived exosomes improves angiogenesis and neurological deficits in rats with intracerebral hemorrhage

Intracerebral hemorrhage (ICH) remains a life-threatening condition due to its high mortality and limited treatment options. This study explores a novel therapeutic strategy using engineered exosomes derived from endothelial progenitor cells (EPC-EXOs) to improve ICH outcomes. EPC-EXOs were modified with a CD47-enriched red blood cell membrane via co-extrusion to enhance their anti-phagocytic properties, thereby reducing degradation by activated microglia after ICH. A minimally invasive endoscopic-guided delivery system was developed to facilitate the targeted intranasal administration of these engineered EPC-EXOs (m-Oe-EXOs), allowing direct entry into brain tissue. We confirmed m-Oe-EXOs' high retention and effective distribution in the brain. Functional analysis demonstrated that EPC-EXOs significantly promoted the proliferation, migration, and angiogenesis of brain microvascular endothelial cells (BMECs), with proteomic analysis identifying HSP90 as a key protein activating the Akt pathway in BMECs. In vivo, m-Oe-EXOs demonstrated therapeutic efficacy by improving blood-brain barrier integrity, reducing hematoma volume, and enhancing neurological recovery in ICH rats. Collectively, our findings highlight the potential of minimally invasive, endoscopic-guided delivery of m-Oe-EXOs as an innovative approach for ICH treatment, providing new insights into targeted, exosomes-based regenerative therapies.

3D culturing as a promising strategy to enhance the angiogenic potential of adipose stem cell-derived secretome: insights into the role of miR-145-5p/ANGPT2 axis

BACKGROUND

Adipose-derived mesenchymal stem cells (ASCs) represent a valid therapeutic option for clinical application in several diseases, mostly due to the paracrine activity of their secretome, exerting pro-angiogenic, antinflammatory and immunosuppressive effects. Recently, 3D culturing models has been shown to significantly influence the intrinsic characteristics of these cells, their gene expression and the secretome's composition, thus affecting ASC paracrine effects and clinical potential. This study aims to investigate the feasibility of exploiting 3D culturing as a tool to improve ASC secretome therapeutic efficacy.

METHODS

ASCs were cultured in monolayers via conventional two-dimensional (2D) methods or induced to form 3D spheroids by seeding them on 96-well ultra-low attachment (ULA) plates. The phenotypical characterization of 3D-ASCs was performed through immunofluorescence analyses. The composition and angiogenic potential of 3D-ASC-derived secretome was assessed by means of protein array and functional tube formation assay, respectively. We analyzed the expression profile of 92 angiogenesis-related genes in 2D versus 3D cultures through a qRT-PCR array, and GO term enrichment analysis followed by network analysis was applied to identify the top hub genes. The expression of specific angiomiRs in 3D-ASCs and their secretome was assessed by qRT-PCR. The role of miR-145-5p was investigated through transfection with specific mimics/anti-miR.

RESULTS

3D-ASCs showed increased stemness, cell-cell and cell-ECM interactions with respect to 2D-cultured cells. 3D culturing increased the secretion of cytokines involved in the promotion of angiogenesis, resulting in improved angiogenic effects on HUVEC cells. Mechanistically, qRT-PCR array data indicated downregulation of angiopoietin-2 (ANGPT2) as a key factor in the 3D-ASC-secretome-induced angiogenesis. In addition, ANGPT2 was recognized as a predicted target of miR-145-5p, one of the angiomiRs found upregulated in 3D-ASCs. Depletion of miR-145-5p significantly altered ASC secretome angiogenic potential and ANGPT2 expression on HUVEC cells.

CONCLUSIONS

All these findings corroborate our hypothesis that 3D culturing is able to positively modulate ASC gene expression and secretome composition in terms of pro-angiogenic potential. Indeed, our study contributes to shed light on the role of the miR-145-5p/ANGPT2 axis in this process, opening the way to innovative potentiation strategies to implement secretome-based therapies, with broad clinical applications.

Lipid droplet-free nanovesicles extruded from stromal vascular fraction improve adipocyte regeneration in the centre of dermal graft

BACKGROUND

The stromal vascular fraction (SVF) has been validated for enhancing tissue regeneration because of its concentration of multipotent cells and growth factors, and for mitigating inflammatory response due to its elimination of the majority of lipid droplets. However, it is difficult for fresh SVF to maintain bioactivity for a long period, and the loss of numerous tangible masses during preparation limits its application in repairing large volume defects. Here, we fabricated a self-assembly nanovesicle extruded from SVF (SVF-EVs) by mechanical shear and co-transplanted it with dermal microparticles to verify its potential for repairing large volume defects.

METHODS

The SVF-EVs were prepared by removing the oil from adipose tissue followed by sequentially extruding SVF through membrane filters. The lipid content of SVF-EVs was compared with SVF using Oil Red O staining. The morphology and adipogenic-related protein of SVF-EVs were characterized. The pro-adipogenic potency of SVF-EVs in vitro was determined using Oil Red O staining of ADSCs, western blot, and qRT-PCR. In vivo, dermal particle grafts mixed with SVF-EVs were subcutaneously transplanted in nude mice and harvested after 4 and 6 weeks. By examining the weight and volume of grafts and histological staining, we explored the effect of SVF-EVs on adipose tissue regeneration and anti-inflammatory ability.

RESULTS

Our results showed that the removal rate of proceeding of SVF-EVs could remove 75.07 ± 2.80% lipid in SVF. The SVF-EVs displayed 100 ~ 150 nm sphere vesicles and contained pro-adipogenic protein. In vitro, SVF-EVs promote the synthesis of lipids in ADSCs. Besides, after co-transplanting of SVF-EVs, adipose regeneration was detected in vivo in the dermal particle grafts.

CONCLUSIONS

These findings revealed that extruding SVF into nanovesicles can effectively reduce the implantation of lipid droplets that cause inflammation, and co-transplanting SVF-EVs with dermal microparticles may be a considerable strategy for large volume defects repair.

Adipose-derived stem cells using fibrin gel as a scaffold enhances post-hepatectomy liver regeneration

We investigated the potential of adipose-derived stem cells (ADSCs) in preventing post-hepatectomy liver failure, emphasizing the necessity of direct administration using a scaffold. A fibrin gel scaffold was employed for ADSCs (gelADSC) to assess their therapeutic impact on liver regeneration in both in vitro and in vivo settings. Experiments were conducted on C57BL/6 mice with normal livers and those with chronic hepatitis. We also explored the role of extracellular vesicles (EVs) secreted by ADSCs in conjunction with fibrin gel. GelADSC showed sustained release of hepatocyte growth factor, vascular endothelial growth factor, and stromal cell-derived factor 1 for at least 7 days in vitro. In vivo, gelADSC significantly enhanced postoperative liver regeneration by upregulating the cell cycle and fatty acid oxidation in both normal and chronically hepatitis-affected mice. The therapeutic effects of gelADSC were potentially favorable over those of intravenously administered ADSCs, especially in mice with chronic hepatitis. Increased EV secretion associated with fibrin gel use was significantly linked to enhanced liver regeneration post-surgery through the promotion of fatty acid oxidation. The findings underscore the enhanced therapeutic potential of gelADSC, particularly in the context of chronic hepatitis, possibly compared to intravenous administration.

Extracellular vesicles from adipose-derived stem cell alleviate diabetic cardiomyopathy by regulating Chit1/NLRP3/Caspase-1-Mediated pyroptosis

It is well-established that chronic hyperglycemia progressively destroys the heart structure, weakening function and leading to diabetic cardiomyopathy (DCM). Extracellular vesicles derived from adipose-derived stem cell (ADSC-EVs) have been reported to have anti-inflammatory and immune-modulating effects, but their role in DCM is still poorly understood. Therefore, this study investigated the impact of ADSC-EVs on DCM and potential mechanisms. ADSC-EVs were isolated from the conditioned media of ADSCs. DCM rat models were established using streptozotocin (STZ) in vivo, and high glucose (HG) stimulated H9c2 cardiomyocytes to establish in vitro model. Then mRNA sequencing identified Chit1 as a key gene. Both in vivo and in vitro experiments demonstrated that chitinase 1 (Chit1) and NLRP3/Caspase-1-mediated pyroptosis levels were significantly upregulated in myocardial tissue of rat diabetic cardiomyopathy and hyperglycemic cardiomyocytes, which was reversed by ADSC-EVs treatment. We next observed that in hyperglycemic cardiomyocytes, downregulating Chit1 also resulted in a decrease in NLRP3/Caspase-1-mediated pyroptosis proteins. To a certain extent, the inhibitory effect of ADSC-EVs on the NLRP3/Caspase-1 signaling pathway was reversed by Chit1 overexpression. Taken together, we identified a novel mechanism by which ADSC-EVs regulate NLRP3/Caspase-1-mediated pyroptosis through Chit1 to alleviate diabetic cardiomyopathy, offering an innovative strategy for DCM treatment.

Artificial Nanovesicles Derived from Cells: A Promising Alternative to Extracellular Vesicles

As naturally secreted vesicles by cells, extracellular vesicles (EVs) play essential roles in modulating cell-cell communication and have significant potential in tissue regeneration, immune regulation, and drug delivery. However, the low yield and uncontrollable heterogeneity of EVs have been obstacles to their widespread translation into clinical practice. Recently, it has been discovered that artificial nanovesicles (NVs) produced by cell processing can inherit the components and functions of the parent cells and possess similar structures and functions to EVs, with significantly higher yields and more flexible functionalization, making them a powerful complement to natural EVs. This review focuses on recent advances in the research of artificial NVs as replacements for natural EVs. We provide an overview comparing natural EVs and artificial NVs and summarize the top-down preparation strategies of NVs. The applications of NVs prepared from stem cells, differentiated cells, and engineered cells are presented, as well as the latest advances in NV engineering. Finally, the main challenges of artificial NVs are discussed.

Advances in the research of immunomodulatory mechanism of mesenchymal stromal/stem cells on periodontal tissue regeneration

Periodontal disease is a highly prevalent disease worldwide that seriously affects people's oral health, including gingivitis and periodontitis. Although the current treatment of periodontal disease can achieve good control of inflammation, it is difficult to regenerate the periodontal supporting tissues to achieve a satisfactory therapeutic effect. In recent years, due to the good tissue regeneration ability, the research on Mesenchymal stromal/stem cells (MSCs) and MSC-derived exosomes has been gradually deepened, especially its ability to interact with the microenvironment of the body in the complex immunoregulatory network, which has led to many new perspectives on the therapeutic strategies for many diseases. This paper systematically reviews the immunomodulatory (including bone immunomodulation) properties of MSCs and their role in the periodontal inflammatory microenvironment, summarizes the pathways and mechanisms by which MSCs and MSC-EVs have promoted periodontal regeneration in recent years, lists potential areas for future research, and describes the issues that should be considered in future basic research and the direction of development of "cell-free therapies" for periodontal regeneration.

DNA Tetrahedron Delivering miR-21-5p Promotes Senescent Bone Defects Repair through Synergistic Regulation of Osteogenesis and Angiogenesis

Compromised osteogenesis and angiogenesis is the character of stem cell senescence, which brought difficulties for bone defects repairing in senescent microenvironment. As the most abundant bone-related miRNA, miRNA-21-5p plays a crucial role in inducing osteogenic and angiogenic differentiation. However, highly efficient miR-21-5p delivery still confronts challenges including poor cellular uptake and easy degradation. Herein, TDN-miR-21-5p nanocomplex is constructed based on DNA tetrahedral (TDN) and has great potential in promoting osteogenesis and alleviating senescence of senescent bone marrow stem cells (O-BMSCs), simultaneously enhancing angiogenic capacity of senescent endothelial progenitor cells (O-EPCs). Of note, the activation of AKT and Erk signaling pathway may direct regulatory mechanism of TDN-miR-21-5p mediated osteogenesis and senescence of O-BMSCs. Also, TDN-miR-21-5p can indirectly mediate osteogenesis and senescence of O-BMSCs through pro-angiogenic growth factors secreted from O-EPCs. In addition, gelatin methacryloyl (GelMA) hydrogels are mixed with TDN and TDN-miR-21-5p to fabricate delivery scaffolds. TDN-miR-21-5p@GelMA scaffold exhibits greater bone repair with increased expression of osteogenic- and angiogenic-related markers in senescent critical-size cranial defects in vivo. Collectively, TDN-miR-21-5p can alleviate senescence and induce osteogenesis and angiogenesis in senescent microenvironment, which provides a novel candidate strategy for senescent bone repair and widen clinical application of TDNs-based gene therapy.

Biofabricated osteoblast-derived nanovesicles as extracellular vesicle mimics for bone repair

Osteoblast-derived extracellular vesicles (EVs) have demonstrated therapeutic utility for bone repair as transporters of key biomolecules capable of accelerating biomineralisation and tissue repair. The clinical translation of these biologically derived nanoparticles, however remains limited due to scalability, heterogeneity and standardisation issues. Herein we investigate the generation of nanovesicles (NVs) from mineralising osteoblasts by extrusion directly compared against natural EV counterparts from the same parental cells. Mineralising osteoblast-derived EVs (MO-EVs) were isolated via ultracentrifugation from cell culture media. The parental osteoblasts were then processed via serial extrusion to <200 nm. EVs and NVs were characterised by comparing their size, concentration and morphology. The presence of tetraspanin markers was detected by Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS). Osteoblasts viability and metabolic activity was assessed after both EV and NV-treatment before comparing their mineralising potency via alizarin red staining. EVs and NVs exhibited similar diameters of approximately 100 nm with a vesicular morphology. EVs were found to be richer in proteins and exhibited a significantly more negative ζ-potential compared to NVs. SP-IRIS analysis confirmed the presence of CD9, CD63 and CD81 in EVs. At both 1 and 10 μg/mL, EVs and NVs reduced the metabolic activity of osteoblasts, however, this was not associated with any cytotoxic effects. The biomineralisation study performed using osteoblasts showed that only EVs significantly increased mineral deposition (p < 0.05) compared to untreated control. In this study, we have established for the first time the biofabrication of cell-derived nanovesicles as a promising alternative to extracellular vesicles derived from mineralising osteoblasts.

Exosomal miR-21-5p derived from endometrial stromal cells promotes angiogenesis by targeting TIMP3 in ovarian endometrial cysts

Endometriosis is a multifactorial gynecological disease, with angiogenesis as a key hallmark. The role of exosomal microRNAs (miRNAs) in endometriosis is not well understood. This study investigates differentially expressed exosomal miRNAs linked to angiogenesis in endometriosis, clarifies their molecular mechanisms, and identifies potential targets. Primary endometrial stromal cells (ESCs) were cultured, and exosomes were extracted. In a co-culture system, ESC-derived exosomes were taken up by human umbilical vein endothelial cells (HUVECs). Endometriosis implant-ESC-derived exosomes (EI-EXOs) significantly promoted HUVEC proliferation, migration and tube formation compared to normal endometrium-exosomes (NE-EXOs), a finding consistent in vivo in mice. MiRNA sequencing and bioinformatics identified differentially expressed miR-21-5p from EI-EXOs, confirmed by RT-qPCR. The miR-21-5p inhibitor or GW4869 attenuated EI-EXO-induced HUVEC proliferation, migration, and tube formation. TIMP3 overexpression diminished the pro-angiogenic effect of EI-EXOs, which was reversed by adding EI-EXOs or upregulating miR-21-5p. These findings validate the crosstalk between ESCs and HUVECs mediated by exosomal miR-21-5p, and confirm the miR-21-5p-TIMP3 axis in promoting angiogenesis in endometriosis. KEY MESSAGES: ESC-derived exosomes were found to be taken up by recipient cells, i.e. HUVECs. Functionally, endometriosis implant-ESC-derived exosomes (EI-EXOs) could significantly promote the proliferation, migration and tube formation of HUVECs compared to normal endometrium-exosomes (NE-EXOs). Through miRNA sequencing and bioinformatics analysis, differentially expressed miR-21-5p released by EI-EXOs was chosen, as confirmed by qRT-PCR. miR-21-5p inhibitor or GW4869 was found to attenuate the proliferation, migration, and tube formation of HUVECs induced by EI-EXOs. In turn, TIMP3 overexpression diminished the pro-angiogenic effect of EI-EXOs, and this angiogenic phenotype was reversed once EI-EXOs were added or miR-21-5p was upregulated.

Mesenchymal stem cell-derived extracellular vesicles in systemic sclerosis: role and therapeutic directions

Systemic sclerosis (SSc) is a complex autoimmune disease with clinical symptoms of vascular damage, immune disorders, and fibrosis, presenting significant treatment challenges and limited therapeutic options. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been demonstrated in numerous studies as more effective than MSCs in treating autoimmune diseases. Recent studies demonstrate that MSC-EVs can significantly ameliorate the symptoms of SSc and mitigate pathological changes such as vascular injury, immune dysregulation, and fibrosis. These findings underscore the promising therapeutic potential of MSC-EVs in the treatment of SSc. MSC-EVs promote angiogenesis, modulate immune dysfunction, and combat fibrosis. This article summarizes the therapeutic applications and possible mechanisms of MSC-EVs for SSc, thereby offering a novel therapeutic direction for the treatment of SSc.

Exosomes derived from tendon stem/progenitor cells enhance tendon-bone interface healing after rotator cuff repair in a rat model

The rate of retear after surgical repair remains high. Mesenchymal stem cells (MSCs) have been extensively employed in regenerative medicine for several decades. However, safety and ethical concerns constrain their clinical application. Tendon Stem/Progenitor Cells (TSPCs)-derived exosomes have emerged as promising cell-free therapeutic agents. Therefore, urgent studies are needed to investigate whether TSPC-Exos could enhance tendon-bone healing and elucidate the underlying mechanisms. In this study, TSPC-Exos were found to promote the proliferation, migration, and expression of fibrogenesis markers in BMSCs. Furthermore, TSPC-Exos demonstrated an ability to suppress the polarization of M1 macrophages while promoting M2 macrophage polarization. In a rat model of rotator cuff repair, TSPC-Exos modulated inflammation and improved the histological structure of the tendon-bone interface, the biomechanical properties of the repaired tendon, and the function of the joint. Mechanistically, TSPC-Exos exhibited high expression of miR-21a-5p, which regulated the expression of PDCD4. The PDCD4/AKT/mTOR axis was implicated in the therapeutic effects of TSPC-Exos on proliferation, migration, and fibrogenesis in BMSCs. This study introduces a novel approach utilizing TSPC-Exos therapy as a promising strategy for cell-free therapies, potentially benefiting patients with rotator cuff tear in the future.

Engineering Three-Dimensional Spheroid Culture for Enrichment of Proangiogenic miRNAs in Umbilical Cord Mesenchymal Stem Cells and Promotion of Angiogenesis

In the field of regenerative medicine, umbilical cord-derived mesenchymal stem cells (UC-MSCs) have a plausible potential. However, traditional two-dimensional (2D) culture systems remain limited in replicating the complex in vivo microenvironment. Thus, three-dimensional (3D) cultures offer a more physiologically relevant model. This study explored the impact of 3D culture conditions on the UC-MSC secretome and its ability to promote angiogenesis, both in vitro and in vivo. In this study, using two distinct methods, we successfully cultured UC-MSCs: in a monolayer (2D-UC-MSCs) and as spheroids formed in U-shaped 96-well plates (3D-UC-MSCs). The presence and expression of proangiogenic miRNAs in the conditioned media (CM) of these cultures were investigated, and differential expression patterns were explored. Particularly, the CM of 3D-UC-MSCs revealed significantly higher levels of miR-21-5p, miR-126-5p, and miR-130a-3p compared to 2D-UC-MSCs. Moreover, the CM from 3D-UC-MSCs revealed a higher effect on endothelial cell proliferation, migration, and tube formation than did the CM from 2D-UC-MSCs, indicating their proangiogenic potential. In an in vivo Matrigel plug mouse model, 3D-UC-MSCs (cells) stimulated greater vascular formation compared to 2D-UC-MSCs (cells). 3D culture of UC-MSCs' secretome improves the promotion of angiogenesis.

Research progress and application prospect of adipose-derived stem cell secretome in diabetes foot ulcers healing

Diabetic foot ulcers (DFUs) are chronic wounds and one of the most common complications of diabetes, imposing significant physical and mental burdens on patients due to their poor prognosis and treatment efficacy. Adipose-derived stem cells (ADSCs) have been proven to promote wound healing, with studies increasingly attributing these beneficial effects to their paracrine actions. Consequently, research on ADSC secretome as a novel and promising alternative for DFU treatment has been extensively conducted. This article provides a comprehensive review of the mechanisms underlying refractory DFU wounds, the secretome of ADSCs, and its role in promoting wound healing in diabetes foot ulcers. And the review aims to provide reliable evidence for the clinical application of ADSC secretome in the treatment of refractory DFU wounds.

Synergistic large segmental bone repair by 3D printed bionic scaffolds and engineered ADSC nanovesicles: Towards an optimized regenerative microenvironment

Achieving sufficient bone regeneration in large segmental defects is challenging, with the structure of bone repair scaffolds and their loaded bioactive substances crucial for modulating the local osteogenic microenvironment. This study utilized digital laser processing (DLP)-based 3D printing technology to successfully fabricate high-precision methacryloylated polycaprolactone (PCLMA) bionic bone scaffold structures. Adipose-derived stem cell-engineered nanovesicles (ADSC-ENs) were uniformly and stably modified onto the bionic scaffold surface using a perfusion device, constructing a conducive microenvironment for tissue regeneration and long bone defect repair through the scaffold's structural design and the vesicles' biological functions. Scanning electron microscopy (SEM) examination of the scaffold surface confirmed the efficient loading of ADSC-ENs. The material group loaded with vesicles (PCLMA-BAS-ENs) demonstrated good cell compatibility and osteogenic potential when analyzed for the adhesion and osteogenesis of primary rabbit bone marrow mesenchymal stem cells (BMSCs) on the material surface. Tested in a 15 mm critical rabbit radial defect model, the PCLMA-BAS-ENs scaffold facilitated near-complete bone defect repair after 12 weeks. Immunofluorescence and proteomic results indicated that the PCLMA-BAS-ENs scaffold significantly improved the osteogenic microenvironment at the defect site in vivo, promoted angiogenesis, and enhanced the polarization of macrophages towards M2 phenotype, and facilitated the recruitment of BMSCs. Thus, the PCLMA-BAS-ENs scaffold was proven to significantly promote the repair of large segmental bone defects. Overall, this strategy of combining engineered vesicles with highly biomimetic scaffolds to promote large-segment bone tissue regeneration holds great potential in orthopedic and other regenerative medicine applications.

A new subtype of artificial cell-derived vesicles from dental pulp stem cells with the bioequivalence and higher acquisition efficiency compared to extracellular vesicles

Extracellular vesicles (EVs) derived from dental pulp stem cells (DPSC) have been shown an excellent efficacy in a variety of disease models. However, current production methods fail to meet the needs of clinical treatment. In this study, we present an innovative approach to substantially enhance the production of 'Artificial Cell-Derived Vesicles (ACDVs)' by extracting and purifying the contents released by the DPSC lysate, namely intracellular vesicles. Comparative analysis was performed between ACDVs and those obtained through ultracentrifugation. The ACDVs extracted from the cell lysate meet the general standard of EVs and have similar protein secretion profile. The new ACDVs also significantly promoted wound healing, increased or decreased collagen regeneration, and reduced the production of inflammatory factors as the EVs. More importantly, the extraction efficiency is improved by 16 times compared with the EVs extracted using ultracentrifuge method. With its impressive attributes, this new subtype of ACDVs emerge as a prospective candidate for the future clinical applications in regenerative medicine.

Evaluating the pro-survival potential of apoptotic bodies derived from 2D- and 3D- cultured adipose stem cells in ischaemic flaps

In the realm of large-area trauma flap transplantation, averting ischaemic necrosis emerges as a pivotal concern. Several key mechanisms, including the promotion of angiogenesis, the inhibition of oxidative stress, the suppression of cell death, and the mitigation of inflammation, are crucial for enhancing skin flap survival. Apoptotic bodies (ABs), arising from cell apoptosis, have recently emerged as significant contributors to these functions. This study engineered three-dimensional (3D)-ABs using tissue-like mouse adipose-derived stem cells (mADSCs) cultured in a 3D environment to compare their superior biological effects against 2D-ABs in bolstering skin flap survival. The findings reveal that 3D-ABs (85.74 ± 4.51) % outperform 2D-ABs (76.48 ± 5.04) % in enhancing the survival rate of ischaemic skin flaps (60.45 ± 8.95) % (all p < 0.05). Mechanistically, they stimulated angiogenesis, mitigated oxidative stress, suppressed apoptosis, and facilitated the transition of macrophages from M1 to M2 polarization (all p < 0.05). A comparative analysis of microRNA (miRNA) profiles in 3D- and 2D-ABs identified several specific miRNAs (miR-423-5p-up, miR30b-5p-down, etc.) with pertinent roles. In summary, ABs derived from mADSCs cultured in a 3D spheroid-like arrangement exhibit heightened biological activity compared to those from 2D-cultured mADSCs and are more effective in promoting ischaemic skin flap survival. These effects are attributed to their influence on specific miRNAs.

De novo design of a nanoregulator for the dynamic restoration of ovarian tissue in cryopreservation and transplantation

The cryopreservation and transplantation of ovarian tissue underscore its paramount importance in safeguarding reproductive capacity and ameliorating reproductive disorders. However, challenges persist in ovarian tissue cryopreservation and transplantation (OTC-T), including the risk of tissue damage and dysfunction. Consequently, there has been a compelling exploration into the realm of nanoregulators to refine and enhance these procedures. This review embarks on a meticulous examination of the intricate anatomical structure of the ovary and its microenvironment, thereby establishing a robust groundwork for the development of nanomodulators. It systematically categorizes nanoregulators and delves deeply into their functions and mechanisms, meticulously tailored for optimizing ovarian tissue cryopreservation and transplantation. Furthermore, the review imparts valuable insights into the practical applications and obstacles encountered in clinical settings associated with OTC-T. Moreover, the review advocates for the utilization of microbially derived nanomodulators as a potent therapeutic intervention in ovarian tissue cryopreservation. The progression of these approaches holds the promise of seamlessly integrating nanoregulators into OTC-T practices, thereby heralding a new era of expansive applications and auspicious prospects in this pivotal domain.

Clay Sculpture-Inspired 3D Printed Microcage Module Using Bioadhesion Assembly for Specific-Shaped Tissue Vascularization and Regeneration

3D bioprinting techniques have enabled the fabrication of irregular large-sized tissue engineering scaffolds. However, complicated customized designs increase the medical burden. Meanwhile, the integrated printing process hinders the cellular uniform distribution and local angiogenesis. A novel approach is introduced to the construction of sizable tissue engineering grafts by employing hydrogel 3D printing for modular bioadhesion assembly, and a poly (ethylene glycol) diacrylate (PEGDA)-gelatin-dopamine (PGD) hydrogel, photosensitive and adhesive, enabling fine microcage module fabrication via DLP 3D printing is developed. The PGD hydrogel printed micocages are flexible, allowing various shapes and cell/tissue fillings for repairing diverse irregular tissue defects. In vivo experiments demonstrate robust vascularization and superior graft survival in nude mice. This assembly strategy based on scalable 3D printed hydrogel microcage module could simplify the construction of tissue with large volume and complex components, offering promise for diverse large tissue defect repairs.

Engineered Extracellular Vesicles in Wound Healing: Design, Paradigms, and Clinical Application

The severe quality of life and economic burden imposed by non-healing skin wounds, infection risks, and treatment costs are affecting millions of patients worldwide. To mitigate these challenges, scientists are relentlessly seeking effective treatment measures. In recent years, extracellular vesicles (EVs) have emerged as a promising cell-free therapy strategy, attracting extensive attention from researchers. EVs mediate intercellular communication, possessing excellent biocompatibility and stability. These features make EVs a potential tool for treating a plethora of diseases, including those related to wound repair. However, there is a growing focus on the engineering of EVs to overcome inherent limitations such as low production, relatively fixed content, and targeting capabilities of natural EVs. This engineering could improve both the effectiveness and specificity of EVs in wound repair treatments. In light of this, the present review will introduce the latest progress in the design methods and experimental paradigms of engineered EVs applied in wound repair. Furthermore, it will comprehensively analyze the current clinical research status and prospects of engineered EVs within this field.

Activation of moderate autophagy promotes survival of fat graft

Clinically unpredictable retention following fat grafting remains outstanding problems because of the unrevealed mechanism of grafted fat survival. The role of autophagy, a process to maintain cellular homeostasis through recycling cellular debris, has yet been to be reported in fat grafting. This study aims to improve the survival of fat grafting through the autophagy. First, the relationship between cell death and autophagy in the early stage of fat grafting was evaluated through immunostaining, RNA sequencing, and western blot. Next, rapamycin, an autophagic agonist, was used for the culturing of adipose-derived stem cells and adipocytes during ischemia. Cell death, autophagy, and reactive oxygen species (ROS) were assayed. Finally, rapamycin was used to assist fat grafting in nude mice. The results demonstrated that the peak of cell death at the early stage of fat grafting was accompanied by a decrease in autophagy. In vitro, during ischemia, 25 nM was confirmed as the optimal dose of rapamycin that reduces cell death with enhanced autophagy and mitophagy, improved mitochondrial quality as well as decreased ROS accumulation. In vivo, promoted mitophagy, alleviated oxidative stress, and decreased cell apoptosis of rapamycin-treated fat grafts were observed in the early stage. In addition, rapamycin increased the survival of fat grafts with increased neovascularization and reduced fibrosis. We suggested that moderate autophagy induced by rapamycin contribute to enhanced ischemic tolerance and long term survival of fat grafts through mitochondrial quality control.