Effective Regenerative Therapies Research Articles

Non-Cytotoxic Graphene Nanoplatelets Upregulate Cell Proliferation and Self-Renewal Genes of Mesenchymal Stem Cells.

Graphene nanoplatelets (UGZ-1004) are emerging as a promising biomaterial in regenerative medicine. This study comprehensively evaluates UGZ-1004, focusing on its physical properties, cytotoxicity, intracellular interactions, and, notably, its effects on mesenchymal stem cells (MSCs). UGZ-1004 was characterized by lateral dimensions and layer counts consistent with ISO standards and demonstrated a high carbon purity of 0.08%. Cytotoxicity assessments revealed that UGZ-1004 is non-toxic to various cell lines, including 3T3 fibroblasts, VERO kidney epithelial cells, BV-2 microglia, and MSCs, in accordance with ISO 10993-5:2020/2023 guidelines. The study focused on MSCs and revealed that UGZ-1004 supports their gene expression alterations related to self-renewal and proliferation. MSCs exposed to UGZ-1004 maintained their characteristic surface markers. Importantly, UGZ-1004 promoted significant upregulation of genes crucial for cell cycle regulation and DNA repair, such as CDK1, CDK2, and MDM2. This gene expression profile suggests that UGZ-1004 can enhance MSC self-renewal capabilities, ensuring robust cellular function and longevity. Moreover, UGZ-1004 exposure led to the downregulation of genes associated with tumor development, including CCND1 and TFDP1, mitigating potential tumorigenic risks. These findings underscore the potential of UGZ-1004 to not only bolster MSC proliferation but also enhance their self-renewal processes, which are critical for effective regenerative therapies. The study highlights the need for continued research into the long-term impacts of graphene nanoplatelets and their application in MSC-based regenerative medicine.

Fabrication and Characterization of Collagen–Magnetic Particle Composite Microbeads for Targeted Cell Adhesion and Proliferation

The integration of the biocompatibility of collagen and the remote-control ability of magnetic elements serves as both a cell scaffold and an actuator. We studied the preparation, characterization, and potential applications of collagen–magnetic particle composite microbeads (CMPMBs). The interplay among collagen concentration, particle size, and surface roughness was found to influence cell adhesion and proliferation. Adsorption and desorption tests showed the reversible attachment of the particles to magnetic sheets, enabling precise spatial control and targeted cell delivery. The particles demonstrated their utility as cell carriers, supporting cell migration and proliferation. These findings showcase the potential of CMPMBs as a promising platform for advanced cell delivery and tissue regeneration applications. The ability to fine-tune particle properties and manipulate them using magnetic fields offers new possibilities for creating complex tissue constructs and controlling cellular behavior, which could contribute to the development of more effective regenerative therapies and tissue engineering approaches.

#407 Human platelet lysate enhanced angiogenic potential of extracellular vesicles derived from mesenchymal stem cells

Abstract Background and Aims Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as a promising regenerative therapy. However, their clinical application is hampered by the presence of xenogeneic components in the medium. In the present study, we aimed to decipher the regenerative properties of MSC-EVs generated under xeno-free conditions to favor the clinical translation of MSC-EVs. Method MSCs were isolated from human umbilical cord and expanded in fetal bovine serum (FBS) and clinical-grade human platelet lysate (HPL) respectively. MSC-EVs were isolated by differential centrifugation combined with size exclusion chromatography and characterized through transmission electron microscopy, nanoparticle tracking analysis, and exoview. Subsequently, a multi-omics approach, comprising transcriptomics, proteomics, and metabolomics, was employed to investigate the molecular cargo of the MSC-EVs. Finally, in vitro and in vivo functional assays were performed to assess the regenerative potential of MSC-EVs in acute kidney injury. Results Our study demonstrated that HPL promoted MSC-EVs production without compromising EVs characteristics. Multi-omics sequencing revealed the stability of HPL cultured MSC-EVs (H-EVs) from different umbilical cord donors and global functional alterations for MSC-EVs under different culture conditions. In comparison to FBS cultured MSC-EVs (F-EVs), the regenerative potential of H-EVs was enhanced especially angiogenesis associated with increased cargo expression. The in vitro studies demonstrated that H-EVs induced more tube-like structure formation and migration. Further, it significantly reduced kidney capillary sparsity in mice with renal ischemic-reperfusion model. Conclusion Our data provided a comprehensive understanding about H-EVs and demonstrated their potential as a safe and effective regenerative therapy, especially targeting angiogenesis-related disorders.

Assessment of Platelet-Rich Plasma Alone and Platelet-Rich Plasma Combined with Bioactive Glass in the Management of Intrabony Defect

ABSTRACT Objectives: To assess the function of platelet-rich plasma (PRP) both only and in combination with bioactive glass in intrabony defects. Materials and Method: Twenty patients were split into two groups with 10 samples each: group I with PRP alone, whereas group II was done with PRP in addition to bioactive glass. Following local anesthesia, full-thickness mucoperiosteal flaps were elevated in the afflicted site, the defect was debrided, and root planning with curettes was performed. Irrigation was then used while in group II- PRP along with bone graft (BG) preservationwas done. Suturing in group I was contained. At day 0 (baseline) and 6 months after surgery, the clinical parameters for probing depth, clinical attachment stage, and radiographic assessment were noted for both groups. Result: When comparing both groups, there was no statistically considerable variation. However, the intragroup comparison for pocket depth and clinical attachment level between baseline and 6 months was significant. Radiographic bone level was not considerably dissimilar across groups; however, it was significantly different between groups Conclusion: Reduced probing depth, higher clinical attachment level, and radiographic evidence of bone fill are clinical outcome measures that are associated with effective regenerative therapy.

Mesenchymal Stem Cells Preconditioned with Hypoxia and Dexamethasone Promote Osteoblast Differentiation Under Stress Conditions.

Bone marrow-derived mesenchymal stem cells (MSCs), which are capable of differentiating into osteoblasts, are used in effective regenerative therapies. MSCs must be prompted to differentiate into osteoblasts for MSC transplantation to be effective. In this study, osteoblast differentiation markers involved in bone formation were evaluated to investigate the stress resistance of bone marrow-derived rat MSCs to dexamethasone and hypoxia and their ability to differentiate into osteoblasts. MSCs were allowed to differentiate into osteoblasts for 21 days in three different environments (dexamethasone treatment, hypoxic conditions [1% oxygen], or both). Osteoblast differentiation potential was evaluated according to alkaline phosphatase levels and a mineralisation assay. Immunofluorescence staining was used to determine the protein expression of the osteoblast differentiation markers type I collagen and osteopontin. MSCs differentiated into osteoblasts under hypoxic conditions but differentiated more slowly upon treatment with dexamethasone and dexamethasone plus hypoxia relative to the control. MSCs preconditioned with dexamethasone or hypoxia and then allowed to differentiate into osteoblasts under similar conditions differentiated comparably to control MSCs. MSCs that developed resistance to dexamethasone or hypoxia differentiated more quickly into osteoblasts than those that did not. The findings suggest that increasing the resistance of MSCs to stress by preconditioning them via dexamethasone or hypoxia exposure could result in more rapid differentiation into osteoblasts following transplantation.

Status of research on the development and regeneration of hair follicles.

Hair loss, or alopecia, is a prevalent condition in modern society that imposes substantial mental and psychological burden on individuals. The types of hair loss, include androgenetic alopecia, alopecia areata, and telogen effluvium; of them, androgenetic alopecia is the most common condition. Traditional treatment modalities mainly involve medical options, such as minoxidil, finasteride and surgical interventions, such as hair transplantation. However, these treatments still have many limitations. Therefore, exploring the pathogenesis of hair loss, specifically focusing on the development and regeneration of hair follicles (HFs), and developing new strategies for promoting hair regrowth are essential. Some emerging therapies for hair loss have gained prominence; these therapies include low-level laser therapy, micro needling, fractional radio frequency, platelet-rich plasma, and stem cell therapy. The aforementioned therapeutic strategies appear promising for hair loss management. In this review, we investigated the mechanisms underlying HF development and regeneration. For this, we studied the structure, development, cycle, and cellular function of HFs. In addition, we analyzed the symptoms, types, and causes of hair loss as well as its current conventional treatments. Our study provides an overview of the most effective regenerative medicine-based therapies for hair loss.

Local delivery of EGFR+NSCs-derived exosomes promotes neural regeneration post spinal cord injury via miR-34a-5p/HDAC6 pathway

Spinal cord injury (SCI) causes severe axon damage, usually leading to permanent paraparesis, which still lacks effective regenerative therapy. Recent studies have suggested that exosomes derived from neural stem cells (NSCs) may hold promise as attractive candidates for SCI treatment. Epidermal Growth Factor Receptor positive NSC (EGFR+NSC) is a subpopulation of endogenous NSCs, showing strong regenerative capability in central nervous system disease. In the current study, we isolated exosomes from the EGFR+NSCs (EGFR+NSCs-Exos) and discovered that local delivery of EGFR+NSCs-Exos can effectively promote neurite regrowth in the injury site of spinal cord-injured mice and improve their neurological function recovery. Using the miRNA-seq, we firstly characterized the microRNAs (miRNAs) cargo of EGFR+NSCs-Exos and identified miR-34a-5p which was highly enriched in EGFR+NSCs derived exosomes. We further interpreted that exosomal miR-34a-5p could be transferred to neurons and inhibit the HDAC6 expression by directly binding to its mRNA, contributing to microtubule stabilization and autophagy induction for aiding SCI repair. Overall, our research demonstrated a novel therapeutic approach to improving neurological functional recovery by using exosomes secreted from a subpopulation of endogenous NSCs and providing a precise cell-free treatment strategy for SCI repair.

Fusogenic Coiled-Coil Peptides Enhance Lipid Nanoparticle-Mediated mRNA Delivery upon Intramyocardial Administration.

Heart failure is a serious condition that results from the extensive loss of specialized cardiac muscle cells called cardiomyocytes (CMs), typically caused by myocardial infarction (MI). Messenger RNA (mRNA) therapeutics are emerging as a very promising gene medicine for regenerative cardiac therapy. To date, lipid nanoparticles (LNPs) represent the most clinically advanced mRNA delivery platform. Yet, their delivery efficiency has been limited by their endosomal entrapment after endocytosis. Previously, we demonstrated that a pair of complementary coiled-coil peptides (CPE4/CPK4) triggered efficient fusion between liposomes and cells, bypassing endosomal entrapment and resulting in efficient drug delivery. Here, we modified mRNA-LNPs with the fusogenic coiled-coil peptides and demonstrated efficient mRNA delivery to difficult-to-transfect induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs). As proof of in vivo applicability of these fusogenic LNPs, local administration via intramyocardial injection led to significantly enhanced mRNA delivery and concomitant protein expression. This represents the successful application of the fusogenic coiled-coil peptides to improve mRNA-LNPs transfection in the heart and provides the potential for the advanced development of effective regenerative therapies for heart failure.

Augmenting mesenchymal stem cell therapy for osteoarthritis via inflammatory priming: a comparative study on mesenchymal stem cells derived from various perinatal tissue sources.

Background: Osteoarthritis (OA), a degenerative disease prevalent among the elderly, poses significant challenges due to its high incidence and disability rates. Regrettably, there exists a lack of effective regenerative therapies for the irreversible degradation of cartilage in OA. Mesenchymal stem cells (MSCs), known for their robust differentiation and immune regulatory capabilities, have emerged as promising candidates for OA treatment. MSCs sourced from perinatal tissues offer the dual advantage of convenience in extraction and ethical non-controversy. However, the heterogeneous nature of MSCs derived from different perinatal tissue sources gives rise to varying therapeutic indications. Moreover, the immune response of MSCs may be modulated under the influence of inflammatory factors. Methods: In this study, we isolated mesenchymal stem cells from distinct parts of human perinatal tissue: umbilical cord-derived MSCs (UC-MSCs), fetal placenta-derived MSCs (FP-MSCs), and umbilical cord placental junction-derived MSCs (CPJ-MSCs). These cells were cultured in vitro and subjected to a 24-hour treatment with the inflammatory mediator Interleukin-1β (IL-1β). Subsequently, the MSCs were evaluated for changes in proliferation, migration, and regulatory capabilities. To assess the comparative anti-injury potential of MSCs from different sources, primary articular chondrocytes (ACs) were exposed to H2O2-induced injury and co-cultured with IL-1β-primed MSCs. Changes in the proliferation, migration, and regulatory abilities of ACs resembling those observed in OA were examined. Results: Following IL-1β treatment, all three types of MSCs displayed decreased rates of proliferation and migration. Notably, their chondrogenic differentiation capacities exhibited an enhancement. Additionally, diverse MSCs exhibited a degree of efficacy in restoring damaged ACs in vitro. Among these, CPJ-MSCs demonstrated superior potential in promoting cartilage cell proliferation, while FP-MSCs displayed notable anti-inflammatory effects. Conclusion: Our findings underscore the substantial capacity of primed FP-MSCs and CPJ-MSCs to alleviate the injury in OA-like ACs. Consequently, this study advocates for the prospective use of preconditioning strategies involving FP-MSCs and CPJ-MSCs in forthcoming OA therapies.

Pathway Analysis of Transcriptional Alterations in the Salivary Gland Following Radiation Exposure

Radiation-induced xerostomia (RIX) is the subjective condition of dry mouth caused by radiation therapy to the head and neck and a result of hyposalivation and altered sialochemistry. Our long-term goal is to develop novel approaches to improve salivary function after radiation therapy. To better understand the molecular alterations induced by radiation in the salivary glands, we performed transcriptional profiling aimed at describing acute and long-term alterations in the murine salivary glands induced by radiation to better design effective regenerative therapies. The submandibular gland (SMG) of male C57Bl/6 mice received 15 Gy in a single fraction using a small animal image-guided irradiator. The mice were followed for 90 days. Saliva was collected at baseline and 7, 60 and 90 days after radiation. Salivary glands were collected for histology 3, 7, 60, and 90 days after radiation. The tissues were analyzed using a multiplex analysis platform processed with the murine whole transcriptome panel to investigate changes in gene expression over time. Using the multiplex analysis platform software, 96 regions of interest corresponding to acini, ducts, and granular convoluted tubules (GCTs) were delineated and gene expression was assessed separately in each area. To confirm the identified alterations, SMG tissue was histologically evaluated for fibrosis (masons tri-chrome), mucin (alcian blue), and amylase (α-amylase). Alterations in the immune microenvironment (CD19, CD3, and F4/80) and salivary gland stem cells (MIST1, SCA, Sox2, and c-Kit) were assessed by immunohistochemistry. Radiation resulted in a significant decrease in salivary production compared to nonirradiated controls (p-value = 0.03). The analysis of the transcriptional pathway identified early alterations in cell communication, DNA damage, and the immune response. Protein metabolism and extracellular matrix remodeling were up-regulated at later time points. Histological evaluation of tissues showed an increase in glandular structure disorganization over time, with a decrease in the size and distribution of the acinar compartments throughout the gland (mean area stained: No RT = 25.81% vs 90d RT = 19.98%, p-value = 0.005). There was an increase in periductal fibrosis within the tissue after 60 days compared to controls. Acutely, there was an increase in the expression of MIST1 and macrophages (mean area stained: No RT = 14.8% vs 7d RT = 18.76%, p-value = 0.0004) within the SMG that had resolved by the 60- and 90-day time points. The results implicate macrophage alterations in radiation-induced salivary gland damage and provide valuable mechanistic insight guiding potential approaches to intervene in RIX. We are pursuing cell therapy-based approaches to prevent and repair damage caused by radiation in order to improve the lives of our patients.

Clinical trials for neuroregenerative therapies for spinal cord injury: what have we learnt so far?

ABSTRACT Introduction There remains a lack of effective regenerative therapies to treat traumatic spinal cord injury (SCI). On a global level, patients living with SCI, their families, and the healthcare system are impacted by the extensive financial burden associated with the management of SCI. Clinical trials are crucial to assess the real-world efficacy of the different emerging neuroregenerative approaches that have shown promise in the pre-clinical stages of research. Areas covered This perspective summarizes and discusses potential solutions to several key challenges that clinical investigators evaluating novel therapeutic strategies to treat SCI might face: 1) the challenges in patient recruitment and meeting enrollment targets with adequate statistical power; 2) the loss of patients to follow-up; 3) the heterogeneity in patient presentation and recovery trajectories; 4) the complex multifaceted pathophysiology of SCI that renders investigations of single therapeutic approaches difficult; 5) the challenge of capturing positive treatment effects of investigative therapies; 6) the high costs associated with conducting clinical trials; 7) the implementation of current guidelines for treating SCI to optimize care delivery and clinical trial conduct; 8) the shift in SCI patient demographics reflective of an aging population; and 9) navigating regulatory bodies to translate therapies into the clinic. Expert opinion There are challenges when conducting SCI clinical trials that span broadly across medical, social, political, and economic considerations. Thus, we should employ an interdisciplinary approach when addressing these challenges in order to facilitate the evaluation of novel treatments for SCI.

Single-cell dissection of human hematopoietic reconstitution after allogeneic hematopoietic stem cell transplantation.

Hematopoietic stem cell transplantation is an effective regenerative therapy for many malignant, inherited, or autoimmune diseases. However, our understanding of reconstituted hematopoiesis in transplant patients remains limited. Here, we uncover the reconstitution dynamics of human allogeneic hematopoietic stem and progenitor cells (HSPCs) at single-cell resolution after transplantation. Transplanted HSPCs underwent rapid and measurable changes during the first 30 days after transplantation, characterized by a strong proliferative response on the first day. Transcriptomic analysis of HSPCs enabled us to observe that immunoregulatory neutrophil progenitors expressing high levels of the S100A gene family were enriched in granulocyte colony-stimulating factor-mobilized peripheral blood stem cells. Transplant recipients who developed acute graft-versus-host disease (aGVHD) infused fewer S100Ahigh immunoregulatory neutrophil progenitors, immunophenotyped as Lin-CD34+CD66b+CD177+, than those who did not develop aGVHD. Therefore, our study provides insights into the regenerative process of transplanted HSPCs in human patients and identifies a potential criterion for identifying patients at high risk for developing aGVHD early after transplant.

Regenerative Effect of Umbilical Cord-Derived Mesenchymal Stromal Cells in a Rat Model of Established Limb Ischemia.

Although regenerative cell therapy is expected to be an alternative treatment for peripheral artery disease (PAD), many regenerative cell therapies have failed to show sufficient efficacy in clinical trials. Most preclinical studies have used acute ischemia models, despite PAD being a chronic disease. In addition, aging and atherosclerosis decrease the quality of a patient's stem cells. Therefore, using a non-acute ischemic preclinical model and stem cells with high regenerative potency are important for the development of effective regenerative therapy. In this study, we assessed the tissue regenerative potential of umbilical cord-derived mesenchymal stromal cells (UCMSCs), which could potentially be an ideal cell source, in a rat model of established ischemia. The regenerative capacity of UCMSCs was analyzed in terms of angiogenesis and muscle regeneration. In vitro analysis showed that UCMSCs secrete high amounts of cytokines associated with angiogenesis and muscle regeneration. In vivo experiments in a rat non-acute ischemia model showed significant improvement in blood perfusion after intravenous injection of UCMSCs compared with injection of culture medium or saline. Histological analysis revealed UCMSCs injection enhanced angiogenesis, with an increased number of von Willebrand factor-positive microcapillaries, and improved muscle regeneration. These results suggest that intravenous administration of UCMSCs may be useful for treating patients with PAD.

Integrated transcriptome-proteome analyses of human stem cells reveal source-dependent differences in their regenerative signature.

Mesenchymal stem cells (MSCs) are gaining increasing prominence as an effective regenerative cellular therapy. However, ensuring consistent and reliable effects across clinical populations has proved to be challenging. In part, this can be attributed to heterogeneity in the intrinsic molecular and regenerative signature of MSCs, which is dependent on their source of origin. The present work uses integrated omics-based profiling, at different functional levels, to compare the anti-inflammatory, immunomodulatory, and angiogenic properties between MSCs from neonatal (umbilical cord MSC [UC-MSC]) and adult (adipose tissue MSC [AD-MSC], and bone marrow MSC [BM-MSC]) sources. Using multi-parametric analyses, we identified that UC-MSCs promote a more robust host innate immune response; in contrast, adult-MSCs appear to facilitate remodeling of the extracellular matrix (ECM) with stronger activation of angiogenic cascades. These data should help facilitate the standardization of source-specific MSCs, such that their regenerative signatures can be confidently used to target specific disease processes.

Development of Methotrexate Complexes Endowed with New Biological Properties Envisioned for Musculoskeletal Regeneration in Rheumatoid Arthritis Environments.

Methotrexate (MTX) administration is the gold standard treatment for rheumatoid arthritis (RA), but its effects are limited to preventing the progression of the disease. Therefore, effective regenerative therapies for damaged tissues are still to be developed. In this regard, MTX complexes of general molecular formula M(MTX)·xH2O, where M = Sr, Zn, or Mg, were synthesized and physicochemically characterized by TGA, XRD, NMR, ATR–FTIR, and EDAX spectroscopies. Characterization results demonstrated the coordination between the different cations and MTX via two monodentate bonds with the carboxylate groups of MTX. Cation complexation provided MTX with new bioactive properties such as increasing the deposition of glycosaminoglycans (GAGs) and alternative anti-inflammatory capacities, without compromising the immunosuppressant properties of MTX on macrophages. Lastly, these new complexes were loaded into spray-dried chitosan microparticles as a proof of concept that they can be encapsulated and further delivered in situ in RA-affected joints, envisioning them as a suitable alternative to oral MTX therapy.

Regeneration Using Adipose-Derived Stem Cell Sheets in a Rabbit Meniscal Defect Model Improves Tensile Strength and Load Distribution Function of the Meniscus at 12 Weeks

The purpose of this study was to evaluate the mechanical properties, such as the tensile strength and load distribution function, of the meniscus tissue regenerated using adipose-derived stem cell (ADSC) sheets in a rabbit meniscal defect model. ADSC sheets were prepared from adipose tissue of rabbits. The anterior half of the medial meniscus was removed from both knees. One knee was transplanted with an ADSC sheet; the contralateral knee was closed without transplantation. Mechanical tests were performed at 4 and 12 weeks posttransplantation. In the tensile test, tensile force was applied to the entire medial meniscus, including the normal area (n= 10/group). Compression tests were performed on the entire knee, with soft tissues other than the ligament removed. A pressure-sensitive film was inserted under the medial meniscus and a 40-N load was applied (n= 5/group). In the tensile test, the elastic modulus in ADSC-treated knees was higher at 12 weeks (ADSC: 70.30 ± 18.50 MPa, control: 43.71 ± 7.11 MPa, P= .009). The ultimate tensile strength (UTS) in ADSC-treated knees at 12 weeks was also higher (ADSC: 22.69 ± 5.87 N, control: 15.45 ± 4.08 N, P= .038). In the compression test, the contact area was larger in the ADSC group at 4 weeks (ADSC: 31.60 ± 8.17 mm2, control: 20.33 ± 2.86 mm2, P= .024) and 12 weeks (ADSC: 41.07 ± 6.09 mm2, control: 30.53 ± 5.47 mm2, P= .04). Peak pressure was significantly lower in ADSC-treated knees at 12 weeks (ADSC: 11.91 ± 1.03 MPa, control: 15.53 ± 2.3 MPa, P= .002). The regenerated meniscus tissue, 12 weeks after transplantation of the ADSC sheets into the meniscal defect area, had high elastic modulus and UTS. In the meniscus-tibia compartment, the contact area was large and the peak pressure was low. ADSC sheets promoted regeneration of meniscus. ADSC sheet transplantation for meniscal defects could be an effective regenerative therapy.

Magnetic bioassembly platforms for establishing craniofacial exocrine gland organoids as aging in vitro models

A multitude of aging-related factors and systemic conditions can cause lacrimal gland (LG) or salivary gland (SG) hypofunction leading to degenerative dry eye disease (DED) or dry mouth syndrome, respectively. Currently, there are no effective regenerative therapies that can fully reverse such gland hypofunction due to the lack of reproducible in vitro aging models or organoids required to develop novel treatments for multi-omic profiling. Previously, our research group successful developed three-dimensional (3D) bioassembly nanotechnologies towards the generation of functional exocrine gland organoids via magnetic 3D bioprinting platforms (M3DB). To meet the needs of our aging Asian societies, a next step was taken to design consistent M3DB protocols to engineer LG and SG organoid models with aging molecular and pathological features. Herein, a feasible step-by-step protocol was provided for producing both LG and SG organoids using M3DB platforms. Such protocol provided reproducible outcomes with final organoid products resembling LG or SG native parenchymal epithelial tissues. Both acinar and ductal epithelial compartments were prominent (21 ± 4.32% versus 42 ± 6.72%, respectively), and could be clearly identified in these organoids. Meanwhile, these can be further developed into aging signature models by inducing cellular senescence via chemical mutagenesis. The generation of senescence-like organoids will be our ultimate milestone aiming towards high throughput applications for drug screening and discovery, and for gene therapy investigations to reverse aging.

Method to Improve Administered Cells Via Intramuscular Route to Augment Efficacy of Regenerative Cell Therapy in The Field of Peripheral Artery Disease

In the field of peripheral artery disease (PAD), regenerative cell therapy has been expected to be a new alternative therapy especially for severely diseased patients. Although various preclinical studies showed promising results, those therapies failed to show sufficient efficacy for actual PAD patients and current guideline do not recommend regenerative therapy for PAD. The disappointing result may be caused by low retention rate of administered substance. Recently we published an article regarding novel method to augment the effect of cell therapy. In this review article, we would like to focus on the importance of improvement in cell survival and prerequisite factors to develop effective regenerative therapy for PAD patients.

Modulation of the Activity of Stem and Progenitor Cells by Immune Cells.

Numerous components of the immune system, including inflammatory mediators, immune cells and cytokines, have a profound modulatory effect on the homeostatic regulation and regenerative activity of endogenous stem cells and progenitor cells. Thus, understanding how the immune system interacts with stem/progenitor cells could build the foundation to design novel and more effective regenerative therapies. Indeed, utilizing and controlling immune system components may be one of the most effective approaches to promote tissue regeneration. In this review, we first summarize the effects of various immune cell types on endogenous stem/progenitor cells, focusing on the tissue healing context. Then, we present interesting regenerative strategies that control or mimic the effect of immune components on stem/progenitor cells, in order to enhance the regenerative capacity of endogenous and transplanted stem cells. We highlight the potential clinical translation of such approaches for multiple tissues and organ systems, as these novel regenerative strategies could considerably improve or eventually substitute stem cell-based therapies. Overall, harnessing the power of the cross-talk between the immune system and stem/progenitor cells holds great potential for the development of novel and effective regenerative therapies.

Decellularization Strategies for Regenerating Cardiac and Skeletal Muscle Tissues.

Cardiovascular disease is the leading cause of death worldwide and is associated with approximately 17.9 million deaths each year. Musculoskeletal conditions affect more than 1.71 billion people globally and are the leading cause of disability. These two areas represent a massive global health burden that is perpetuated by a lack of functionally restorative treatment options. The fields of regenerative medicine and tissue engineering offer great promise for the development of therapies to repair damaged or diseased tissues. Decellularized tissues and extracellular matrices are cornerstones of regenerative biomaterials and have been used clinically for decades and many have received FDA approval. In this review, we first discuss and compare methods used to produce decellularized tissues and ECMs from cardiac and skeletal muscle. We take a focused look at how different biophysical properties such as spatial topography, extracellular matrix composition, and mechanical characteristics influence cell behavior and function in the context of regenerative medicine. Lastly, we describe emerging research and forecast the future high impact applications of decellularized cardiac and skeletal muscle that will drive novel and effective regenerative therapies.