Regenerative Capability Research Articles

Physical and histological comparison of three-dimensional interconnected porous carbonate apatite bone graft fabricated with cylindrical and spherical granules

Three-dimensional interconnected porous carbonate apatite (3D-CO3Ap) bone grafts facilitate rapid bone replacement because of their structure, which supports cellular infiltration. Existing 3D-CO3Ap grafts have demonstrated limited mechanical strength, with a maximum compressive strength of 3 MPa. By fusing polymer-bound CaCO3 granules, followed by the debinding and compositional transformation of the granules via a dissolution–precipitation reaction, we successfully fabricated 3D-CO3Ap grafts that exhibited remarkably enhanced compressive strengths, which were recorded at 14.9 ± 3.7 MPa. The use of spherical granules, which provide more uniform and effective intergranular contacts than cylindrical granules, was key to achieving higher mechanical strength and superior bone formation. 3D-CO3Ap developed with spherical granules not only exhibited higher compressive strength, but also enhanced new bone formation compared with those fabricated with cylindrical granules. This study underscores the significance of porous microstructure design in 3D-CO3Ap, highlighting its critical role in optimizing both mechanical properties and bone regeneration capabilities.

A Systematic Review of Stem Cell Applications in Maxillofacial Regeneration.

Regenerative medicine is revolutionizing oral and maxillofacial surgeries with stem cells, particularly mesenchymal stem cells, for tissue and bone regeneration. Despite promising in-vitro results, human trials are limited. A systematic review is needed to evaluate stem cell efficacy in maxillofacial issues, aiming to improve surgical outcomes and patient satisfaction. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines, this review included peer-reviewed articles (2013-2023) on stem cells in oral surgery, excluding non-English publications, abstracts, reviews, and opinion pieces. Searches were conducted in PubMed, Web of Science, OVID, Cochrane, Dentistry & Oral Sciences Source-Ebscohost, and Scopus. Two authors independently screened titles and abstracts, resolving disagreements by consensus. Full-text analysis involved extracting key data, verified by a secondary reviewer and additional quality checks. From 3540 initial articles, 2528 were screened after removing duplicates, and 7 met the inclusion criteria after excluding irrelevant studies. Key themes included the safety and efficacy of stem cell therapy, and bone regeneration and quality. Studies predominantly used mesenchymal stem cells. Findings showed positive outcomes in clinical safety and effectiveness and significant potential for bone regeneration. This systematic review highlights the potential of stem cell therapies in maxillofacial applications, supporting their safety, efficacy, and bone regeneration capabilities. Further research is needed to standardize protocols and confirm long-term benefits.

Novel GSK-3 inhibitor based universal dentin bonding system: A comprehensive analysis of dentinal repair and improved bond strength

The aim of the study was to describe the formulation of a novel universal adhesive system, based on a GSK-3 (glycogen synthetase kinase-3) inhibitor (Tideglusib®), and to evaluate its bond strength and dentinal repair capability. Tideglusib® was added to Ultradent Peak Universal Dentin Bonding Agent to make experimental adhesives (0.5 %, 1 %, 2 % final concentration). They were applied to teeth which were sectioned, stored for 24 h, or 2 years then bond strengths measured. Baseline stiffness of bonded dentin beams was tested using the three-point bending test. Animal experiments were performed to provide specimens for microcomputed tomography imaging after adhesive application. Collagen matrix was evaluated using transmission electron microscopy. The cytotoxicity of the modified adhesives was determined using fibroblastic cells. Molecular modelling evaluated binding of the Tideglusib® molecule to active sites on collagen and the adhesive components. TGFβ-1/and BMP-2 in human dentin matrices were measured and interfaces were scanned using SkyScan 2211. Adhesives’ stability tests were done. ResultsRMSD (root mean square deviation) analysis indicated simulation has equilibrated with changes for globular proteins (p < 0.05). Specimens from 0.5 %, and 1 % Tideglusib® groups displayed adhesive penetration with Micro-CT imaging and a significant increase in dentin density was seen. Specimens from the same groups showed cells with large masses of cytoplasm with focal adhesion points. Bond strength decreased significantly (p < 0.05) with increased storage time. Gradual release (p < 0.05) of both TGFβ-1 and BMP-2 from hTDMs with 0.5 % and 1 % Tideglusib® groups occurred and higher elastic moduli (p < 0.05). Collagen-based amide and proline Raman bands were seen in the Tideglusib® groups. ConclusionIncorporation of Tideglusib® in experimental Universal Adhesive System at 1 % improved adhesive bond strength and promoted dentinal repair. Application of Tideglusib® based adhesive conserve mechanical properties of the tooth structure and promote regenerative capability so can be expected to extend the service life of adhesive restorations in clinical situations.

In Vitro Models for Peripheral Nerve Regeneration.

Peripheral nerve injury (PNI) resulting in lesions is highly prevalent clinically, but current therapeutic approaches fail to provide satisfactory outcomes in many patients. While peripheral nerves have intrinsic regenerative capacity, the regenerative capabilities of peripheral nerves are often insufficient to restore full functionality. This highlights an unmet need for developing more effective strategies to repair damaged peripheral nerves and improve regenerative success. Consequently, researchers are actively exploring a variety of therapeutic strategies, encompassing the local delivery of trophic factors or bioactive molecules, the design of advanced biomaterials that interact with regenerating axons, and augmentation with nerve guidance conduits or complex prostheses. However, clinical translation of these technologies remains limited, emphasizing the need for continued research on peripheral nerve regeneration modalities that can enhance functional restoration. Experimental models that accurately recapitulate key aspects of peripheral nerve injury and repair biology can accelerate therapeutic development by enabling systematic testing of new techniques. Advancing regenerative therapies for PNI requires bridging the gap between basic science discoveries and clinical application. This review discusses different in vitro models of peripheral nerve injury and repair, including their advantages, limitations, and potential applications.

Overexpression of CGRP receptor attenuates tendon graft degeneration in anterior cruciate ligament reconstruction.

Cell apoptosis or necrosis, extracellular matrix loss, and excessive inflammation may induce tendon graft degeneration. The impairment in the regeneration capability of nerve fibers and blood vessels may be the critical cause. Calcitonin gene-related peptide (CGRP), exhibiting a short half-life, favors cell proliferation, nerve fiber regeneration and angiogenesis. We aimed to investigate the effects of CGRP receptor-mediated signaling on tendon graft integrity and study if the modulation pathways are ascribed to cell proliferation, nerve fiber and blood vessel regeneration. A total of three groups in mice with ACL reconstruction were established: the control group (PBS treatment), the adenovirus vectors expressing CGRP receptor (CALCRL) treated group (Adv-Calcrl treatment), and the adenovirus vectors carrying shRNA targeting Calcrl treated group (Adv-shCalcrl treatment). The histological assessment indicated the Adv-Calcrl treatment was favored while the Adv-shCalcrl significantly impaired tendon graft integrity. TUNEL staining revealed a significant decreased number of apoptotic cells in the Adv-Calcrl group relative to the control group and the adv-shCalcrl group. Compared to the control group and the Adv-shCalcrl group, the Adv-Calcrl group showed significantly enhanced proliferation of nestin positive cells. Of note, the Adv-Calcrl treatment significantly increased EMCN expression at the tendon graft relative to the control and the Adv-shCalcrl groups, which may be ascribed to attenuation of the Hippo signaling pathway. Importantly, the Adv-Calcrl treatment significantly increased sensory nerve fibers and also PIEZO2 levels. Our results demonstrate the activation of CGRP receptor-mediated signaling attenuated tendon graft degeneration, which was ascribed to enhanced proliferation of Nestin positive cells, angiogenesis, and nerve fiber outgrowth.

Evaluating the Reparative Potential of Secretome from Patient-Derived Induced Pluripotent Stem Cells during Ischemia–Reperfusion Injury in Human Cardiomyocytes

During a heart attack, ischemia causes losses of billions of cells; this is especially concerning given the minimal regenerative capability of cardiomyocytes (CMs). Heart remuscularization utilizing stem cells has improved cardiac outcomes despite little cell engraftment, thereby shifting focus to cell-free therapies. Consequently, we chose induced pluripotent stem cells (iPSCs) given their pluripotent nature, efficacy in previous studies, and easy obtainability from minimally invasive techniques. Nonetheless, using iPSC secretome-based therapies for treating injured CMs in a clinical setting is ill-understood. We hypothesized that the iPSC secretome, regardless of donor health, would improve cardiovascular outcomes in the CM model of ischemia–reperfusion (IR) injury. Episomal-generated iPSCs from healthy and dilated cardiomyopathy (DCM) donors, passaged 6–10 times, underwent 24 h incubation in serum-free media. Protein content of the secretome was analyzed by mass spectroscopy and used to treat AC16 immortalized CMs during 5 h reperfusion following 24 h of hypoxia. IPSC-derived secretome content, independent of donor health status, had elevated expression of proteins involved in cell survival pathways. In IR conditions, iPSC-derived secretome increased cell survival as measured by metabolic activity (p &lt; 0.05), cell viability (p &lt; 0.001), and maladaptive cellular remodelling (p = 0.052). Healthy donor-derived secretome contained increased expression of proteins related to calcium contractility compared to DCM donors. Congruently, only healthy donor-derived secretomes improved CM intracellular calcium concentrations (p &lt; 0.01). Heretofore, secretome studies mainly investigated differences relating to cell type rather than donor health. Our work suggests that healthy donors provide more efficacious iPSC-derived secretome compared to DCM donors in the context of IR injury in human CMs. These findings illustrate that the regenerative potential of the iPSC secretome varies due to donor-specific differences.

Low-energy electric shock ameliorates cell proliferation, morphallaxis, and regeneration via driving key regenerative proteins in earthworm and 3T3 cells

Electric stimulation regulates many cellular processes like cell proliferation, differentiation, apoptosis and cellular migration. Despite its crucial role in regulating stem cells and regeneration, it remains underexplored in both in-vivo and in-vitro settings. In this study, Eudrilus eugeniae are subjected to electric stimulation (1.5 V) prior and after amputation and which augments regeneration up to double-time. Blocking epimorphosis using 2 M thymidine retracts regeneration kinetics to one-third but such inhibition was rescued by applying electric stimulation which propels an overactive morphallaxis pattern of regeneration. Excreting electric stimulation on control worms shows minimal impact, whereas it enhances the key regenerative proteins like VEGF, COX2, YAP, c-Myc, and Wnt3a on amputated worms. Upon blocking epimorphosis, all these key regenerative proteins are down-regulated but through electric stimulation, the cells are reprogrammed to express a triple fold of the mentioned regenerative proteins, that further promotes morphallaxis. In 3T3 cells, electric stimulation accelerates cell proliferation and migrations in 5 secs exposure and it exerts its function by overexpressing VEGF mediated by MEK1. Wnt3a expression was gradually upregulated in increasing exposure (5 and 25 secs) which aids in maintaining the stemness property. The molecular mechanism underlying regeneration capability can assist in designing novel therapeutic applications.

Effects of plant hormones and genotypes on anther culture response of safflower (Carthamus tinctorius L.)

Safflower (Carthamus tinctorius L.) belongs to the composite family with various uses, from the stem to the seeds. In vitro flowering and embryo rescue are common techniques for improving safflower hybrid fertility by overcoming breeding constraints. However, anther culture expedites the production of superior types. The aim of the study was to evaluate the effect of plant hormones and genotypes on anther culture responses and to develop a suitable protocol. In both safflower genotypes, callus, shoot, and root formation were investigated using ten factorial hormone treatments. To promote callus induction and shoot regeneration, variable doses of Thidiazuron (TDZ) at 1 mg/l indole butyric acid (IBA) and variable benzylaminopurine (BAP) at 0.5 mg/l NAA were added to the MS medium, respectively. ½ MS media with varying IBA concentrations at a fixed 0.5 mg/l NAA were used for root regeneration. Results showed that Turkan was superior in all aspects of callus induction, and the highest degree of callus formation (46 %) was observed at 0.5 mg/l TDZ. On the other hand, the local safflower performed better for shoot and root regeneration. The highest shoot regeneration capacity (20 %) was shown at 2.0 mg/l BAP, while shoot rooting was reached (21 %) at 1.0 mg/l IBA of culture media. Despite successful in vitro regeneration, acclimated plantlets did not survive in the glasshouse. In this study, we demonstrated the higher capability for both shoot and root regeneration of calli produced from local safflower anthers. More effort is required to improve shoot and root development for both genotypes.

Visualization Experimental Investigation on Flow Regulation and Oil Displacement Characteristics of Gel Foam in Fractured-Vuggy Carbonate Reservoirs.

Fractured-vuggy reservoirs experience severe channeling during water and gas injection operations, and conventional foam shows weak regeneration capabilities in large-scale fracture spaces, thus failing to effectively seal them. Gel foam combines the advantages of both foam and gel, significantly enhancing the foam's stability and showing good suitability in fractured-vuggy reservoirs. In this article, the plugging and flow regulation properties of gel foam in fractures were studied through fracture displacement experiments. The dynamic plugging capability of gel foam was superior to that of ordinary foam, and its plugging effect was significantly influenced by the fracture opening. Gel foam had strong retention capacity in fractures, and after plugging large-opening fractures, the diversion rate of small-opening fractures was increased by at least 83.3 times during subsequent parallel water flooding, making the flow regulation effect remarkable. Through the oil displacement experiments in typical fractured-vuggy models, the profile control law and enhanced oil recovery performance of gel foam under different fractured-vuggy structures were studied. In the regular fractured-vuggy network, gel foam adhered to occupy the fractured-vuggy space for plugging and controlled the top gas migration direction to synergistically drive the recovery of remaining oil, ultimately achieving a recovery of 95%. In the combination of fractures and irregular vugs, due to the density, gel foam continuously pushed down and right along the fractures to the vugs, pushing the crude oil and formation water in the vugs to migrate to the production well. The recovery of the gel foam flooding stage was as high as 48%, and the final recovery reached 93.5; only a small amount of shielded remaining oil was difficult to drive. The research results are of great significance to the application of gel foam in enhancing oil recovery in fractured-vuggy reservoirs.

Functional poly(e-caprolactone)/SerMA hybrid dressings with dimethyloxalylglycine-releasing property improve cutaneous wound healing

Medical dressings with multifunctional properties, including potent regeneration capability and good biocompatibility, are increasingly needed in clinical practice. In this study, we reported a novel hybrid wound dressing (PCL/SerMA/DMOG) that combines electrospun PCL membranes with DMOG-loaded methacrylated sericin (SerMA) hydrogel. In such a design, DMOG molecules are released from the hybrid dressing in a sustained mannerin vitro. A series ofin vitroassays demonstrated that DMOG-loaded hybrid dressing has multiple biological functions, including promotion of human umbilical vein endothelial cells proliferation and migration,in vitrovascularization, and the generation of intracellular NO. When applied to the cutaneous wound, the PCL/SerMA/DMOG dressing significantly accelerated wound closure and tissue regeneration by promoting angiogenesis in the wound area, collagen deposition, and cell proliferation within the wound bed. These results highlight the potential clinical application of PCL/SerMA/DMOG hybrid dressings as promising alternatives for accelerating wound healing via improved biocompatibility and angiogenesis amelioration.

Ultrasensitive Electrochemical Biosensors Based on Allosteric Transcription Factors (aTFs) for Pb2+ Detection.

Exposure to Pb2+ in the environment, especially in water, poses a significant threat to human health and urgently necessitates the development of highly sensitive Pb2+ detection methods. In this study, we have integrated the high sensitivity of electrochemical techniques with allosteric transcription factors (aTFs) to develop an innovative electrochemical biosensing platform. This biosensors leverage the specific binding and dissociation of DNA to the aTFs (PbrR) on electrode surfaces to detect Pb2+. Under the optimal conditions, the platform has a broad linear detection range from 1 pM to 10 nM and an exceptionally low detection threshold of 1 pM, coupled with excellent selectivity for Pb2+. Notably, the biosensor demonstrates regenerative capabilities, enabling up to five effective Pb2+ measurements. After one week of storage at 4 °C, effective lead ion detection was still possible, demonstrating the biosensor's excellent stability, this can effectively save the cost of detection. The biosensor also achieves a recovery rate of 93.3% to 106.6% in real water samples. The biosensor shows its potential as a robust tool for the ultrasensitive detection of Pb2+ in environmental monitoring. Moreover, this research provides new insights into the future applications of aTFs in electrochemical sensing.

Internally-crosslinked alginate dialdehyde/alginate/gelatin-based hydrogels as bioprinting inks for prospective cardiac tissue engineering applications

Cardiovascular diseases represent a worldwide social and economic challenge, due to heart tissue limited regenerative capabilities. 3D bioprinted cell-laden constructs are a promising approach to develop patches for cardiac regeneration or in vitro models for new drug preclinical discovery and validation. However, the development of bioinks with optimal mechanical, rheological, and biological properties is still a challenge. Although alginate (Alg)-based bioinks have been extensively explored, such hydrogels lack cell adhesion properties and degradability. Additionally, 3D Alg structures are usually obtained by micro-extrusion bioprinting exploiting conventional external cross-linking methods, which introduce inhomogeneities and unpredictability in construct formation. This work exploits Alg internal ionic gelation mechanism to obtain homogeneous self-standing multilayered 3D printed constructs without employing support baths or post-printing crosslinking treatments, combining an insoluble calcium salt (calcium carbonate, CaCO3) with an acidifying agent (D-(+)-Glucono-1,5-lactone, GDL) to promote controlled release of calcium ions. Alg was blended with oxidized alginate (ADA) and gelatin (Gel) to achieve degradable and cell adhesive hydrogels for cardiac tissue engineering. Firstly, ADA/Alg bioink composition was tailored by varying polymer weight ratio (keeping ADA as the main component) and calcium ions concentration to achieve cardiac tissue-like viscoelastic properties. Then, the amount of Gel in ADA/Alg hydrogels was optimized to support adult human cardiac fibroblasts (AHCFs) adhesion, producing shear thinning inks with tunable viscoelastic properties (G&amp;rsquo; 650-1300 Pa) and degradation profile (40-80% weight loss after 21 days in phosphate buffered saline, PBS) by varying Gel concentration. ADA/Alg/Gel hydrogels showed a shear thinning behavior suitable for 3D bioprinting and dependent on ink stabilization time, due to the gradual pH-triggered release of calcium ions over time. AHCFs-laden ADA/Alg/Gel bioinks could be successfully printed producing scaffolds with high shape fidelity and good cell viability post-printing. Finally, 3D AHCF-laden and H9C2-laden ADA/Alg/Gel bioinks with the highest gelatin content (25% w/w) allowed cell adhesion after 24 hours of incubation, showing potential application for cardiac tissue modelling. This research presented a comprehensive framework for advancing the design of bioink formulations enabling the printing of cell-adhesive and self-supporting constructs.

EphA4 Targeting Peptide-Conjugated Extracellular Vesicles Rejuvenates Adult Neural Stem Cells and Exerts Therapeutic Benefits in Aging Rats.

Aging and various neurodegenerative diseases cause significant reduction in adult neurogenesis and simultaneous increase in quiescent neural stem cells (NSCs), which impact the brain's regenerative capabilities. To deal with this challenging issue, current treatments involve stem cell transplants or prevention of neurodegeneration; however, the efficacy or success of this process remains limited. Therefore, extensive and focused investigation is highly demanding to overcome this challenging task. Here, we have designed an efficient peptide-based EphA4 receptor-targeted ligand through an in silico approach. Further, this strategy involves chemical conjugation of the peptide with adipose tissue stem cell-derived EV (Exo-pep-11). Interestingly, our newly designed engineered EV, Exo-pep-11, targets NSC through EphA4 receptors, which offers promising therapeutic advantages by stimulating NSC proliferation and subsequent differentiation. Our result demonstrates that NSC successfully internalized Exo-pep-11 in both in vitro culture conditions as well as in the in vivo aging rats. We found that the uptake of Exo-pep-11 decreased by ∼2.3-fold when NSC was treated with EphA4 antibody before Exo-pep-11 incubation, which confirms the receptor-specific uptake of Exo-pep-11. Exo-pep-11 treatment also increases NSC proliferation by ∼1.9-fold and also shows ∼1.6- and ∼2.4-fold increase in expressions of Nestin and ID1, respectively. Exo-pep-11 also has the potential to increase neurogenesis in aging rats, which is confirmed by ∼1.6- and ∼1.5-fold increases in expressions of TH and Tuj1, respectively, in rat olfactory bulb. Overall, our findings highlight the potential role of Exo-pep-11 for prospective applications in combating age-related declines in NSC activity and neurogenesis.

Synergistic potential of stem cells and microfluidics in regenerative medicine.

Regenerative medicine has immense potential to revolutionize healthcare by using regenerative capabilities of stem cells. Microfluidics, a cutting-edge technology, offers precise control over cellular microenvironments. The integration of these two fields provides a deep understanding of stem cell behavior and enables the development of advanced therapeutic strategies. This critical review explores the use of microfluidic systems to culture and differentiate stem cells with precision. We examined the use of microfluidic platforms for controlled nutrient supply, mechanical stimuli, and real-time monitoring, providing an unprecedented level of detail in studying cellular responses. The convergence of stem cells and microfluidics holds immense promise for tissue repair, regeneration, and personalized medicine. It offers a unique opportunity to revolutionize the approach to regenerative medicine, facilitating the development of advanced therapeutic strategies and enhancing healthcare outcomes.

Enhancing Cartilage Repair: Surgical Approaches, Orthobiologics, and the Promise of Exosomes.

Treating cartilage damage is challenging as its ability for self-regeneration is limited. Left untreated, it can progress to osteoarthritis (OA), a joint disorder characterized by the deterioration of articular cartilage and other joint tissues. Surgical options, such as microfracture and cell/tissue transplantation, have shown promise as techniques to harness the body's endogenous regenerative capabilities to promote cartilage repair. Nonetheless, these techniques have been scrutinized due to reported inconsistencies in long-term outcomes and the tendency for the defects to regenerate as fibrocartilage instead of the smooth hyaline cartilage native to joint surfaces. Orthobiologics are medical therapies that utilize biologically derived substances to augment musculoskeletal healing. These treatments are rising in popularity because of their potential to enhance surgical standards of care. More recent developments in orthobiologics have focused on the role of exosomes in articular cartilage repair. Exosomes are nano-sized extracellular vesicles containing cargo such as proteins, lipids, and nucleic acids, and are known to facilitate intercellular communication, though their regenerative potential still needs to be fully understood. This review aims to demonstrate the advancements in cartilage regeneration, highlight surgical and biological treatment options, and discuss the recent strides in understanding the precise mechanisms of action involved.

Biomimetic bilayer phase change hydrogels with enhanced water adsorption and desorption for evaporative cooling

Hygroscopic hydrogels, reliable carriers for water-based evaporative materials, undergo shrinkage after evaporative cooling, and the consequent reduction in hygroscopic sites can significantly impair their recyclability in cooling period. To realize cyclic evaporative cooling for rapid regeneration and evaporation, bilayer phase change hydrogel (BPH) concept combining an upper layer of hygroscopic polymer film (CaCl2@ carboxymethyl cellulose/konjac glucomannan films, CaCl2@CMC/KGM, MAF) with a lower layer of hygroscopic hydrogel (CaCl2@poly(vinyl alcohol)/sodium tetraborate decahydrate hydrogel, CaCl2@PVA/Borax, PCH), is presented in this paper. The high liquid–vapor phase change enthalpy of BPH (1274 J/g) enables it to continuously and rapidly remove heat. Benefiting from the MAF hygroscopic porous skeleton, the saturated BPH exhibited a faster water evaporation rate (2.15 kg m−2 h−1) and comparable water vapor transmission rate (1.61 kg m−2 h−1) at 50 °C. After being heated at 50 °C for 1 h, BPH requires 9h to regain its initial mass at 25 °C, 90 % RH. Fifteen moisture adsorption–desorption cycles demonstrate the excellent cyclic regeneration capability of BPH. COMSOL Multiphysics simulation results indicate that evaporative cooling in BPH provides excellent heat dissipation (reduced by about 27 °C). BPH reduces the peak temperatures of a mobile phone by 7.8 °C while charging and 6.5 °C while gaming. This design will contribute to the future cooling of heat-related devices and global sustainability.

Inhibition of MAT2A Impairs Skeletal Muscle Repair Function.

The regenerative capacity of muscle, which primarily relies on anabolic processes, diminishes with age, thereby reducing the effectiveness of therapeutic interventions aimed at treating age-related muscle atrophy. In this study, we observed a decline in the expression of methionine adenosine transferase 2A (MAT2A), which synthesizes S-adenosylmethionine (SAM), in the muscle tissues of both aged humans and mice. Considering MAT2A's critical role in anabolism, we hypothesized that its reduced expression contributes to the impaired regenerative capacity of aging skeletal muscle. Mimicking this age-related reduction in the MAT2A level, either by reducing gene expression or inhibiting enzymatic activity, led to inhibiting their differentiation into myotubes. In vivo, inhibiting MAT2A activity aggravated BaCl2-induced skeletal muscle damage and decreased the number of satellite cells, whereas supplementation with SAM improved these effects. RNA-sequencing analysis further revealed that the Fas cell surface death receptor (Fas) gene was upregulated in Mat2a-knockdown C2C12 cells. Suppressing MAT2A expression or activity elevated Fas protein levels and increased the proportion of apoptotic cells. Additionally, inhibition of MAT2A expression or activity increased p53 expression. In conclusion, our findings demonstrated that impaired MAT2A expression or activity compromised the regeneration and repair capabilities of skeletal muscle, partially through p53-Fas-mediated apoptosis.

Integrin-linked kinase control dental pulp stem cell senescence via the mTOR signaling pathway.

Human dental pulp stem cells (HDPSCs) showed an age-dependent decline in proliferation and differentiation capacity. Decline in proliferation and differentiation capacity affects the dental stromal tissue homeostasis and impairs the regenerative capability of HDPSCs. However, which age-correlated proteins regulate the senescence of HDPSCs remain unknown. Our study investigated the proteomic characteristics of HDPSCs isolated from subjects of different ages and explored the molecular mechanism of age-related changes in HDPSCs. Our study showed that the proliferation and osteogenic differentiation of HDPSCs were decreased, while the expression of aging-related genes (p21, p53) and proportion of senescence-associated β-galactosidase (SA-β-gal)-positive cells were increased with aging. The bioinformatic analysis identified that significant proteins positively correlated with age were enriched in response to the mammalian target of rapamycin (mTOR) signaling pathway (ILK, MAPK3, mTOR, STAT1, and STAT3). We demonstrated that OSU-T315, an inhibitor of integrin-linked kinase (ILK), rejuvenated aged HDPSCs, similar to rapamycin (an inhibitor of mTOR). Treatment with OSU-T315 decreased the expression of aging-related genes (p21, p53) and proportion of SA-β-gal-positive cells in HDPSCs isolated from old (O-HDPSCs). Additionally, OSU-T315 promoted the osteoblastic differentiation capacity of O-HDPSCs in vitro and bone regeneration of O-HDPSCs in rat calvarial bone defects model. Our study indicated that the proliferation and osteoblastic differentiation of HDPSCs were impaired with aging. Notably, the ILK/AKT/mTOR/STAT1 signaling pathway may be a major factor in the regulation of HDPSC senescence, which help to provide interventions for HDPSC senescence.

Regenerative Medicine in Orthopedic Surgery: Expanding Our Toolbox.

Regenerative medicine leverages the body's inherent regenerative capabilities to repair damaged tissues and address organ dysfunction. In orthopedics, this approach includes a variety of treatments collectively known as orthoregeneration, encompassing modalities such as prolotherapy, extracorporeal shockwave therapy, pulsed electromagnetic field therapy, therapeutic ultrasound, and photobiomodulation therapy, and orthobiologics like platelet-rich plasma and cell-based therapies. These minimally invasive techniques are becoming prominent due to their potential for fewer complications in orthopedic surgery. As regenerative medicine continues to advance, surgeons must stay informed about these developments. This paper highlights the current state of regenerative medicine in orthopedics and advocates for further clinical research to validate and expand these treatments to enhance patient outcomes.

Continuous‐Gradient Mineralized Hydrogel Synthesized via Gravitational Osmosis for Osteochondral Defect Repair

AbstractThe repair of hierarchical osteochondral defects requires complex gradient reconstruction at different levels, with continuous‐gradient mineralization being crucial. Strategies for achieving continuous‐gradient mineralization have rarely been reported. Here, a continuous‐gradient mineralized hydrogel is prepared using simple gravitational osmosis of a ≈2 nm amorphous calcium phosphate nanocluster (ACPC) suspension into composite organic frameworks for osteochondral regeneration. During gravitational infiltration, ACPC underwent gradual mineralization, resulting in the spontaneous formation of hydroxyapatite (HAP). The continuous‐gradient mineralized hydrogel aligned closely with the normal osteochondral structure, thereby effectively promoting repair of the cartilage and subchondral bone. In the cartilage layer, organic compounds improved the oxidative stress environment induced by injury and complemented the extracellular matrix of the cartilage. In the subchondral bone layer, HAP from the continuously mineralized hydrogel induced intracellular calcium accumulation in mesenchymal stem cells (MSCs), activating calcium/calmodulin‐dependent protein kinase 2 (CaMK2) and promoting osteogenic differentiation of MSCs through the calcium signaling pathway. Ultimately, compared with the nongradient hydrogel, this innovative gradient mineralization method exhibited significantly enhanced regeneration capabilities for osteochondral defects, as evidenced by metrics, such as bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N). This holistic strategy provides hope in the field of osteochondral repair.