Regenerative Cell Therapy Research Articles

Expression of reprogramming factors in mesenchymal stem cells isolated from equine umbilical cord Wharton’s jelly and amniotic fluid

Stem cells represent the most promising population for regenerative cell therapy and have gained much attention during the recent past. Mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into trilineages. Like haematopoietic cells, mesenchymal cells have been shown to proliferate and form fibroblast-like colonies in vitro. Despite major progress in our general knowledge related to the application of adult stem cells, finding alternative sources for bone marrow MSCs has remained a challenge. A wide diversity of isolation procedures for mesenchymal stromal cells from various tissues of the placenta, umbilical cord and Wharton's jelly have been described for humans and other species. In this study, we isolated established umbilical cord Wharton’s jelly as a primary source for isolation of mesenchymal stem cells since it is a rich source of stem cells and no ethical concerns are involved. Equine umbilical cord Wharton’s jelly segments were collected during foaling time and digested enzymatically and cultured in-vitro in culture medium. In addition to the study of their morphology and colony forming units, the expression of reprogramming factors by the isolated MSCs were also studied. The isolated MSCs were observed to be plastic adherent, clonogenic and their morphology were polygonal, star shaped and fibroblast like. They revealed a strong expression of pluripotent stemness markers OCT-4, SOX-2, Nanog and KLF-4. From the current study, it can be concluded that Wharton's jelly is a rich source of stem cells with stemness properties expressing the reprogramming factors and mesenchymal like morphology and could be used as an alternate for the bone marrow derived mesenchymal stem cells for cell based regenerative therapies.

Long-Term, Noninvasive In Vivo Tracking of Progenitor Cells Using Multimodality Photoacoustic, Optical Coherence Tomography, and Fluorescence Imaging.

Stem cell regenerative medicine therapies have emerged as promising treatments for currently incurable diseases. A remaining challenge for cell therapies is the ability to track the migration and distribution of the transplanted cells in a long-term, noninvasive manner in vivo to assess their efficacy. This study develops a noninvasive, and high spatial resolution photoacoustic microscopy (PAM) and optical coherence tomography (OCT) imaging system for in vivo tracking of subretinally injected progenitor human retinal pigment epithelium cells (ARPE-19) labeled with chainlike gold nanoparticle (CGNP) clusters in RPE damage. CGNP provided significant PAM, OCT, and fluorescence signals to selectively track the migration of ARPE-19 cells in living rabbit eyes for 3 months. PAM and OCT imaging allow accurate anatomical information to determine the exact retinal layer in which the transplanted ARPE-19 cells are located which was confirmed by histology. This presents an efficient and advanced technology to visualize fundamental biological processes of cell therapies in complex in vivo environments in real time.

Combined Application of Prototype Ultrasound and BSA-Loaded PLGA Particles for Protein Delivery.

To develop an in vitro culture system for tissue engineering to mimic the in vivo environment and evaluate the applicability of ultrasound and PLGA particle system. For tissue engineering, large molecules such as growth factors for cell differentiation should be supplied in a controlled manner into the culture system, and the in vivo microenvironment need to be reproduced in the system for the regulation of cellular function. In this study, portable prototype ultrasound with low intensity was devised and tested for protein release from bovine serum albumin (BSA)-loaded poly(lactic-co-glycolic acid) (PLGA) particles. BSA-loaded PLGA particles were prepared using various types of PLGA reagents and their physicochemical properties were characterized including particle size, shape, or aqueous wetting profiles. The BSA-loaded formulation showed nano-ranged size distribution with optimal physical stability during storage period, and protein release behaviors in a controlled manner. Notably, the application of prototype ultrasound with low intensity influenced protein release patterns in the culture system containing the BSA-loaded PLGA formulation. The results revealed that the portable ultrasound set controlled by the computer could contribute for the protein delivery in the culture medium. This study suggests that combined application with ultrasound and protein-loaded PLGA encapsulation system could be utilized to improve culture system for tissue engineering or cell regeneration therapy.

Insights on the Regeneration Potential of Müller Glia in the Mammalian Retina.

Müller glia, the major glial cell types in the retina, maintain retinal homeostasis and provide structural support to retinal photoreceptors. They also possess regenerative potential that might be used for retinal repair in response to injury or disease. In teleost fish (such as zebrafish), the Müller glia response to injury involves reprogramming events that result in a population of proliferative neural progenitors that can regenerate the injured retina. Recent studies have revealed several important mechanisms for the regenerative capacity of Müller glia in fish, which may shed more light on the mechanisms of Müller glia reprogramming and regeneration in mammals. Mammalian Müller glia can adopt stem cell characteristics, and in response to special conditions, be persuaded to proliferate and regenerate, although their native regeneration potential is limited. In this review, we consider the work to date revealing the regenerative potential of the mammalian Müller glia and discuss whether they are a potential source for cell regeneration therapy in humans.

Label-free imaging for quality control of cardiomyocyte differentiation

Human pluripotent stem cell (hPSC)-derived cardiomyocytes provide a promising regenerative cell therapy for cardiovascular patients and an important model system to accelerate drug discovery. However, cost-effective and time-efficient platforms must be developed to evaluate the quality of hPSC-derived cardiomyocytes during biomanufacturing. Here, we develop a non-invasive label-free live cell imaging platform to predict the efficiency of hPSC differentiation into cardiomyocytes. Autofluorescence imaging of metabolic co-enzymes is performed under varying differentiation conditions (cell density, concentration of Wnt signaling activator) across five hPSC lines. Live cell autofluorescence imaging and multivariate classification models provide high accuracy to separate low (< 50%) and high (≥ 50%) differentiation efficiency groups (quantified by cTnT expression on day 12) within 1 day after initiating differentiation (area under the receiver operating characteristic curve, 0.91). This non-invasive and label-free method could be used to avoid batch-to-batch and line-to-line variability in cell manufacturing from hPSCs.

Silencing the G-protein coupled receptor 3-salt inducible kinase 2 pathway promotes human \u03b2 cell proliferation

Loss of pancreatic β cells is the hallmark of type 1 diabetes, for which provision of insulin is the standard of care. While regenerative and stem cell therapies hold the promise of generating single-source or host-matched tissue to obviate immune-mediated complications, these will still require surgical intervention and immunosuppression. Here we report the development of a high-throughput RNAi screening approach to identify upstream pathways that regulate adult human β cell quiescence and demonstrate in a screen of the GPCRome that silencing G-protein coupled receptor 3 (GPR3) leads to human pancreatic β cell proliferation. Loss of GPR3 leads to activation of Salt Inducible Kinase 2 (SIK2), which is necessary and sufficient to drive cell cycle entry, increase β cell mass, and enhance insulin secretion in mice. Taken together, our data show that targeting the GPR3-SIK2 pathway is a potential strategy to stimulate the regeneration of β cells.

Cortical adult neurogenesis and its biological implication

AbstractIt is well established that adult neurogenesis occurs in the subventricular zone and the subgranular zone, but a controversy remains about adult neurogenesis in other regions. The cerebral cortex is the most controversial site and has long been of interest to not only neuroscientists, but also scientists with broad backgrounds and medical doctors since the late 19th century. However, recent studies have been gradually clarifying that neurogenesis in the adult cerebral cortex occurs, especially under pathological conditions. These studies suggest that endogenous neural stem cells and/or progenitor cells might exist in or around the cerebral cortex, and be useful for regenerative cell therapy in cases of brain insults and diseases. In this review, recent literature regarding neurogenesis in the adult cerebral cortex is summarized, and the possibility of cell therapy for cortex‐related disorders is discussed.

Vitrification of Dog Skin Tissue as a Source of Mesenchymal Stem Cells.

The purpose of this study was to develop an efficient vitrification system for cryopreservation of dog skin tissues as a source of stable autologous stem cells. In this study, we performed vitrification using four different cryoprotectants, namely, ethylene glycol (EG), dimethyl-sulfoxide (Me2SO), EG plus Me2SO, and EG plus Me2SO plus sucrose, and analyzed the behaviors of cells established from warmed tissues. Tissues vitrified with 15% EG, 15% Me2SO, and 0.5 M sucrose had a normal histological appearance and the highest cell viability after cell isolation, and thus, this cocktail of cryoprotectants was used in subsequent experiments. We evaluated proliferation and apoptosis of cells derived from fresh and vitrified tissues. These cells had a normal spindle-like morphology after homogenization through subculture. Dog dermal skin stem cells (dDSSCs) derived from fresh and vitrified tissues had similar proliferation capacities, and similar percentages of these cells were positive for mesenchymal stem cell markers at passage 3. The percentage of apoptotic cell did not differ between dDSSCs derived from fresh and vitrified tissues. Real-time PCR analysis revealed that dDSSCs at passage 3 derived from fresh and vitrified tissues had similar expression levels of pluripotency (OCT4, SOX2, and NANOG), proapoptotic (BAX), and antiapoptotic (BCL2 and BIRC5) genes. Both types of dDSSCs successfully differentiated into the mesenchymal lineage (adipocytes and osteocytes) under specific conditions, and their differentiation potentials did not significantly differ. Furthermore, the mitochondrial membrane potential of dDSSCs derived from vitrified tissues was comparable with that of dDSSCs derived from fresh tissues. We conclude that vitrification of dog skin tissues using cocktail solution in combination of 15% EG, 15% Me2SO, and 0.5 M sucrose allows efficient banking of these tissues for regenerative stem cell therapy and conservation of genetic resources.

Hypoimmune induced pluripotent stem cell–derived cell therapeutics treat cardiovascular and pulmonary diseases in immunocompetent allogeneic mice

The emerging field of regenerative cell therapy is still limited by the few cell types that can reliably be differentiated from pluripotent stem cells and by the immune hurdle of commercially scalable allogeneic cell therapeutics. Here, we show that gene-edited, immune-evasive cell grafts can survive and successfully treat diseases in immunocompetent, fully allogeneic recipients. Transplanted endothelial cells improved perfusion and increased the likelihood of limb preservation in mice with critical limb ischemia. Endothelial cell grafts transduced to express a transgene for alpha1-antitrypsin (A1AT) successfully restored physiologic A1AT serum levels in mice with genetic A1AT deficiency. This cell therapy prevented both structural and functional changes of emphysematous lung disease. A mixture of endothelial cells and cardiomyocytes was injected into infarcted mouse hearts, and both cell types orthotopically engrafted in the ischemic areas. Cell therapy led to an improvement in invasive hemodynamic heart failure parameters. Our study supports the development of hypoimmune, universal regenerative cell therapeutics for cost-effective treatments of major diseases.

Platelet-Targeted Gene Therapy of Hemophilia a Using Hematopoietic Stem Cells Derived from Genome-Edited Induced Pluripotent Stem Cells

Hemophilia A (HA), an X-linked recessive hereditary bleeding disorder, is caused by mutations in the F8 gene, which encodes the coagulation factor VIII (FVIII). Replacement therapy is the mainstay in clinic, but it can also cause inhibitory antibodies and is therefore restricted in wide use. Effective therapy of HA with inhibitors needs to be considered as a matter of priority. Evidence has been obtained that functional FVIII can be ectopically expressed and stored in platelets after transplantation of F8 gene modified-hematopoietic stem cells (HSCs), and the stored-FVIII can be released during the activation of platelets to exert therapeutic effect on HA with inhibitors. This unique strategy, however, requires enough sources of HSCs and a safe and effective way of HSCs modification. Induced pluripotent stem cells (iPSCs) are capable of self-renewing, large-scale expansion and differentiating into almost all types of cells and tissues. These features make iPSCs a promising path in the field of regenerative medicine and cell therapy. The recently developed techniques of genome editing, especially the CRISPR/Cas9 system, provide a powerful tool for gene therapy, owing to significantly reduced risk of insertional mutagenesis as compared to the random integration in retroviral-mediated gene therapy. Hence, we seek to explore the possibility of utilizing iPSCs and CRISPR/Cas9 in the platelet-targeted gene therapy of HA.Here, we established a HA mouse iPSCs (HA-iPSCs) derived from mouse-tail tip fibroblasts, and verified the pluripotency of these cells. On the other hand, we synthesized a codon optimized B domain-deleted FVIII construct (opBDD-F8) in order to enhance the expression efficiency of FVIII. Indeed, our in vitro expression data showed that opBDD-F8 achieved a nearly 4-fold increase of FVIII level as compared to BDD-F8, either under control of the platelet specific GPαIIb promoter or CMV promoter. This increased FVIII expression was further confirmed by hydrodynamic tail vein injection. Then, we inserted the GPαIIb promoter controlled opBDD-F8 (2bopF8) cassette into the Rosa26 locus of HA-iPSCs via CRISPR/Cas9-mediated homologous recombination, and obtained 2bopF8-modified HA-iPSCs (2bopF8-HAiPSCs). No obvious off-target mutation was found in the clones. To generate functional HSCs for transplantation, we performed an in vivo differentiation strategy. We injected 2bopF8-HAiPSCs with hHoxB4 retrovirus transduction into immunodeficient mice to create teratoma, from which we isolated HSCs. The cells were subsequently transplanted into lethally irradiated HA recipient mice. Hematopoiesis was recovered in the recipients, and normal peripheral blood cell numbers sustained for more than 40 weeks. FVIII was detected in platelets of the recipients, suggesting that the cells were originated from 2bopF8-HAiPSCs and FVIII could be expressed during thrombopoiesis. Bleeding phenotype was corrected in the recipients, demonstrating that FVIII released during platelet activation was functional in ensuring coagulation cascade. Furthermore, we did secondary HSC transplantation by using the recipients as the donors. FVIII activity could be detected in the platelets of the new recipients, and bleeding phenotype was corrected in these animals, indicating that long-term HSCs could be generated from 2bopF8-HAiPSCs. During the whole period of research, the recipients were all in good health without teratoma formation or other sickness. Furthermore, we successfully produced chimeric mice with the 2bopF8-HAiPSCs. FVIII expression was observed in the platelets and HSCs were isolated from the mice. Transplantation of these HSCs into lethally irradiated HA mice reconstituted hematopoiesis and generated platelets with FVIII activity. In these mice, coagulation deficiency was also corrected.Taken together, our proof of principle studies suggest that the genome-edited 2bopF8-HAiPSCs could differentiate towards HSCs with physiological functions, and the functional platelets could be derived from these HSCs. Meanwhile, FVIII could be expressed in platelets and abrogate bleeding diathesis of HA mice. Thus, iPSC-derived HSCs together with genome editing tools represent a potential route for platelet-targeted gene therapy that is worth further investigation. DisclosuresNo relevant conflicts of interest to declare.

Combining stem cells in myocardial infarction: The road to superior repair?

Myocardial infarction irreversibly destroys millions of cardiomyocytes in the ventricle, making it the leading cause of heart failure worldwide. Over the past two decades, many progenitor and stem cell types were proposed as the ideal candidate to regenerate the heart after injury. The potential of stem cell therapy has been investigated thoroughly in animal and human studies, aiming at cardiac repair by true tissue replacement, by immune modulation, or by the secretion of paracrine factors that stimulate endogenous repair processes. Despite some successful results in animal models, the outcome from clinical trials remains overall disappointing, largely due to the limited stem cell survival and retention after transplantation. Extensive interest was developed regarding the combinational use of stem cells and various priming strategies to improve the efficacy of regenerative cell therapy. In this review, we provide a critical discussion of the different stem cell types investigated in preclinical and clinical studies in the field of cardiac repair. Moreover, we give an update on the potential of stem cell combinations as well as preconditioning and explore the future promises of these novel regenerative strategies.

Long Term Survival and Limb Salvage in Patients With Non-Revascularisable Chronic Limb Threatening Ischaemia

The aim of this study was to provide long term survival and limb salvage rates for patients with non-revascularisable (NR) chronic limb threatening ischaemia (CLTI). This was a retrospective review of prospectively collected data, derived from a randomised controlled trial (JUVENTAS) investigating the use of a regenerative cell therapy. Survival and limb salvage of the index limb in CLTI patients without viable options for revascularisation at inclusion were analysed retrospectively. The primary outcome was amputation free survival, a composite of survival and limb salvage, at five years after inclusion in the original trial. In 150 patients with NR-CLTI, amputation free survival was 43% five years after inclusion. This outcome was driven by an equal rate of all cause mortality (35%) and amputation (33%). Amputation occurred predominantly in the first year. Furthermore, 33% of those with amputation subsequently died within the investigated period, with a median interval of 291 days. Five years after the initial need for revascularisation, about half of the CLTI patients who were deemed non-revascularisable survived with salvage of the index limb. Although the prospects for these high risk patients are still poor, under optimal medical care, amputation free survival seems comparable with that of revascularisable CLTI patients, while the major amputation rate within one year, especially among NR-CLTI patients with ischaemic tissue loss, is very high.

Mesenchymal stem cells derived from epicardial adipose tissue reverse cardiac remodeling in a rabbit model of myocardial infarction.

Myocardial infarction (MI) is one of the most important causes of death. MI-related tissue loss and cardiac remodeling may result in heart failure. Intramyocardial injection of mesenchymal stem cells derived from adipose tissues, in acute MI animal models, has shown promising regenerative capabilities. This study aimed to investigate the myocardial regenerative capacity of epicardial adipose tissue-derived mesenchymal stem cells (ADSCs) in a rabbit model of MI. A rabbit model of MI was performed in three groups: a sham-operated group, a control group, and a treatment group. MI was induced by coronary artery ligation via thoracotomy in the first operation. Four weeks after the first operation, intramyocardial injections of phosphate-buffered saline (PBS; control group) or ADSCs (10×106 in 100 μL; treatment group) were performed in the peri-infarct zone. Four weeks after the second operation, rabbits were sacrificed for further analysis. A significant increase in ejection fraction (p<0.0001) was detected in the treatment group, along with a significant increase in vascular density (p<0.001) and a significant decrease in infarct size (p<0.05) compared to the control group. Epicardial adipose tissue is a rich source of mesenchymal stem cells, which can differentiate into cardiomyocytes, as well as having neoangiogenic properties. Due to its potential to ameliorate chronic ischemic changes in the heart, it may be preferable in cardiac regenerative cell therapies.

Breast milk MSCs upregulated β-cells PDX1, Ngn3, and PCNA expression via remodeling ER stress /inflammatory /apoptotic signaling pathways in type 1 diabetic rats

Type 1 diabetes mellitus (T1DM) is one of the autoimmune diseases characterized by beta-cell dysfunction with serious health complications. Br-MSCs represent a novel valid candidate in regenerative medicine disciplines. Yet, the full potential of Br-MSCs in managing type 1 diabetes remains elusive. Indeed, this study was designed to explore a novel approach investigating the possible regenerative capacity of Br-MSCs in type1 diabetic islet on the level of the cellular mRNA expression of different molecular pathways involved in pancreatic beta-cell dysfunction. Sixty adult male Sprague-Dawley rats were randomly assigned into 3 groups (20 rats each); the control group, type1 diabetic group, and the type 1 diabetic Br-MSCs treated group. And, for the first time, our results revealed that intraperitoneally transplanted Br-MSCs homed to the diabetic islet and improved fasting blood glucose, serum insulin level, pancreatic oxidative stress, upregulated pancreatic mRNA expression for: regenerative markers (Pdx1, Ngn3, PCNA), INS, beta-cell receptors (IRS1, IRβ, PPARγ), pancreatic growth factors (IGF-1, VEGFβ1, FGFβ), anti-inflammatory cytokine (IL10) and anti-apoptotic marker (BCL2) too, Br-MSCs downregulated pancreatic mRNA expression for: inflammatory markers (NFKβ, TNFα, IL1β, IL6, IL8, MCP1), apoptotic markers for both intrinsic and extrinsic pathways (FAS, FAS-L, P53, P38, BAX, Caspase3), ER stress markers (ATF6, ATF3, ATF4, BIP, CHOP, JNK, XBP1) and autophagy inhibitor (mTOR). In conclusion, Br-MSCs could be considered as a new insight in beta cell regenerative therapy improving the deteriorated diabetic islet microenvironment via modulating; ER stress, inflammatory, and apoptotic signaling pathways besides, switching on the cellular quality control system (autophagy) thus enhancing beta-cell function.

Targeted inhibition of STAT3 in neural stem cells promotes neuronal differentiation and functional recovery in rats with spinal cord injury.

STAT3 is expressed in neural stem cells (NSCs), where a number of studies have previously shown that STAT3 is involved in regulating NSC differentiation. However, the possible molecular mechanism and role of STAT3 in spinal cord injury (SCI) remain unclear. In the present study, the potential effect of STAT3 in NSCs was first investigated by using short hairpin RNA (shRNA)-mediated STAT3 knockdown in rat NSCs in vitro. Immunofluorescence of β3-tubulin and glial fibrillary acidic protein staining and western blotting showed that knocking down STAT3 expression promoted NSC neuronal differentiation, where the activity of mTOR was upregulated. Subsequently, rats underwent laminectomy and complete spinal cord transection followed by transplantation of NSCs transfected with control-shRNA or STAT3-shRNA at the injured site in vivo. Spinal cord-evoked potentials and the Basso-Beattie-Bresnahan scores were used to examine functional recovery. In addition, axonal regeneration and tissue repair were assessed using retrograde tracing with FluoroGold, hematoxylin and eosin, Nissl and immunofluorescence staining of β3-tubulin, glial fibrillary acidic protein and microtubule-associated protein 2 following SCI. The results showed that transplantation with NSCs transfected with STAT3-RNA enhanced functional recovery following SCI and promoted tissue repair in rats, in addition to improving neuronal differentiation of the transplanted NSCs in the injury site. Taken together, in vitro and in vivo evidence that inhibiting STAT3 could promote NSC neuronal differentiation was demonstrated in the present study. Therefore, transplantation with NSCs with STAT3 expression knocked down appears to hold promising potential for enhancing the benefit of NSC-mediated regenerative cell therapy for SCI.

Formulation and Characterization of Microcapsules Encapsulating PC12 Cells as a Prospective Treatment Approach for Parkinson’s Disease

Parkinson's disease (PD) is the second most common neurological disorder, associated with decreased dopamine levels in the brain. The goal of this study was to assess the potential of a regenerative medicine-based cell therapy approach to increase dopamine levels. In this study, we used rat adrenal pheochromocytoma (PC12) cells that can produce, store, and secrete dopamine. These cells were microencapsulated in the selectively permeable polymer membrane to protect them from immune responses. For fabrication of the microcapsules, we used a modified Buchi spray dryer B-190 that allows for fast manufacturing of microcapsules and is industrially scalable. Size optimization of the microcapsules was performed by systematically varying key parameters of the spraying device. The short- and long-term stabilities of the microcapsules were assessed. In the in vitro study, the cells were found viable for a period of 30days. Selective permeability of the microcapsules was confirmed via dopamine release assay and micro BCA protein assay. We found that the microcapsules were permeable to the small molecules including dopamine and were impermeable to the large molecules like BSA. Thus, they can provide the protection to the encapsulated cells from the immune cells. Griess's assay confirmed the non-immunogenicity of the microcapsules. These results demonstrate the effective fabrication of microcapsules encapsulating cells using an industrially scalable device. The microcapsules were stable, and the cells were viable inside the microcapsules and were found to release dopamine. Thus, these microcapsules have the potential to serve as the alternative or complementary treatment approach for PD.

Arthroscopic Bursa-Augmented Rotator Cuff Repair: A Vasculature-preserving Technique for Subacromial Bursal Harvest and Tendon Augmentation

Rotator cuff repairs are associated with suboptimal outcomes and possibly greater incidence of retears if the biological healing environment is compromised. Strategies to optimize tendon–bone healing include the use of bioinductive scaffolds and regenerative stem cell therapy. The subacromial bursa has been shown to have significant pluripotent stem cell potency for tendon healing and has the advantage of easy accessibility and no added cost. However, a reproducible surgical technique for bursal mobilization, harvest, and vascularity preservation has not been described. We describe our technique for vasculature-preserving bursal mobilization and harvest of the entire posterosuperior and lateral subacromial bursa, and its use in rotator cuff repair augmentation is presented. The technique involves mobilization of the bursa as a continuous layer by maintain its medial and lateral vascularity. The bursa is advanced laterally, and the “vascular bursal duvet” and cuff tendons are repaired together as a tendon–bursa unit.

Stem Cells and Intervertebral Disc Regeneration Overview-What They Can and Can't Do.

Low back pain (LPB) is the main cause of disability worldwide with enormous socioeconomic burdens. A major cause of LBP is intervertebral disc degeneration (IDD): a chronic, progressive process associated with exhaustion of the resident cell population, tissue inflammation, degradation of the extracellular matrix and dehydration of the nucleus pulposus. Eventually, IDD may lead to serious sequelae including chronic LBP, disc herniation, segmental instability, and spinal stenosis, which may require invasive surgical interventions. However, no treatment is actually able to directly tackle IDD and hamper the degenerative process. In the last decade, the intradiscal injection of stem cells is raising as a promising approach to regenerate the intervertebral disc. This review aims to describe the rationale behind a regenerative stem cell therapy for IDD as well as the effect of stem cells following their implantation in the disc environment according to preclinical studies. Furthermore, actual clinical evidence and ongoing trials will be discussed, taking into account the future perspective and current limitations of this cutting-edge therapy. A literature analysis was performed for this narrative review. A database search of PubMed, Scopus and ClinicalTrials.gov was conducted using "stem cells" combined with "intervertebral disc", "degeneration" and "regeneration" without exclusion based on publication date. Articles were firstly screened on a title-abstract basis and, subsequently, full-text were reviewed. Both preclinical and clinical studies have been included. The database search yielded recent publications from which the narrative review was completed. Based on available evidence, intradiscal stem cell therapy has provided encouraging results in terms of regenerative effects and reduction of LBP. However, multicenter, prospective randomized trials are needed in order confirm the safety, efficacy and applicability of such a promising treatment.

Biophysical and Biochemical Cues of Biomaterials Guide Mesenchymal Stem Cell Behaviors.

Mesenchymal stem cells (MSCs) have been widely used in the fields of tissue engineering and regenerative medicine due to their self-renewal capabilities and multipotential differentiation assurance. However, capitalizing on specific factors to precisely guide MSC behaviors is the cornerstone of biomedical applications. Fortunately, several key biophysical and biochemical cues of biomaterials that can synergistically regulate cell behavior have paved the way for the development of cell-instructive biomaterials that serve as delivery vehicles for promoting MSC application prospects. Therefore, the identification of these cues in guiding MSC behavior, including cell migration, proliferation, and differentiation, may be of particular importance for better clinical performance. This review focuses on providing a comprehensive and systematic understanding of biophysical and biochemical cues, as well as the strategic engineering of these signals in current scaffold designs, and we believe that integrating biophysical and biochemical cues in next-generation biomaterials would potentially help functionally regulate MSCs for diverse applications in regenerative medicine and cell therapy in the future.

First Approach to the Management of Orthopedic Injuries of the Hindfoot

Hindfoot pain is a common clinical problem that can be due to multiple alterations, it can appear due to bone or soft tissue causes, it is established in a small anatomical area. There are different methods of treatment for these conditions, ranging from simple guidelines in lifestyle to surgery. In this work, patients are divided into four groups with different treatment methods, each group was assigned a different therapeutic option, which will increase its degree of invasion as the number of the group increases. Infiltration with platelet-rich plasma (PRP) is a new technique of cell regenerative therapy and was applied in one of the groups, taking advantage of the regenerative, healing and anti-inflammatory properties of the mentioned therapy.