Application of Stem Cells in Tissue Engineering

Stem cells have become an important source of seed cells for tissue engineering because they are relatively easy to expand in vitro and can be induced to differentiate into various cell types in vitro or in vivo. In the current stage, most stem cell researches focus on in vitro studies, including in vitro induction and phenotype characterization. Our center has made a great deal of effort in the in vivo study by using stem cells as seed cells for tissue construction. We have used bone marrow s…     

Culture of Neural Stem Cells in Calcium-alginate Microbeads

1 Introduction Recent research shows that neural stem cells may play an important role in the nerve injury reparation and nerve disease treatment. The shortage of the source and the number of NSCs, however, is the main challenge for its clinic application. In this situation, expansion of NSCs in large scale and culture in three dimensional environment are very worth of exploration. Notablely, the shear stress existed in bioreactors can cause serious cell injury especially for the shear sens…     

Isolation and Culture of Rabbit Marrow-derived Mesenchymal Stem Cells

1 IntroductionRepair of tissues like bone, cartilage, muscle, etc., is a tough problem in clinical treatment. The recent research show that there are plenty of mesenchymal stem cells (MSCs) in myeloid tissue besides hemopoietic stem cells(HSCs).Just as the pluripotential hemopoietic stem cell can give bone marrow tissue excellent hemopoietic ability and maintain the metabolism of, MSCs can give potential repair ability to bone, cartilage tissue injury~([1]).But compared with the HSCs, the…     

Identification and Isolation of Human Dental Pulp Stem Cells

1 IntroductionDentinal repair in the postnatal organism occurs through the activity of specialized cells, odontoblasts, that are thought to be maintained by an as yet undefined precursor population associated with pulp tissue. Adult pulp stem cells was fo…     

Stem Cells in Tooth Tissue Regeneration—Challenges and Limitations

The accelerated pace of research in the stem cell field in recent decades and the accumulated body of knowledge has spurred the interest in potential clinical applications of stem cells in all branches of medicine including regenerative dentistry. In humans, embryonic and adult stem cells are two major groups of cells that can serve as a donor source in tissue engineering strategies based on ex-vivo cellular expansion. It has been shown that adult stem cell populations are present in all examined living tissues of the organism, thus being a crucial source of tissue homeostasis and regeneration, and offering a target population for in situ stimulation of extensive tissue regeneration. Experimental findings indicate that in the complex structure of the tooth organ, both periodontal and endodontic tissues harbour adult stem cells with characteristics peculiar to early stages of cellular differentiation. Myriad of strategies incorporating both embryonic and adult stem cells for the regeneration of a particular tooth structure or the whole teeth were proposed; however their successful application to solve real problems encountered in the clinical practice of dentistry remains an elusive and challenging objective.     

Expressions of Collagen I and III in Mesenchymal Stem Cells Co-cultured with Ligament Fibroblasts

1 IntroductionThe poor or failed healing of some tendons and ligaments leads to the requirement of surgical replacement of grafts. Tissue engineering offers the appealing potential to improve the reconstruction of tissues presenting acceptable biological and mechanical properties. Mesenchymal stem cells (MSCs) have been shown to differentiate into several cells. The implantation of MSCs into damaged rabbit Achilles tendons significantly improved the structural properties of the neo-tissues,…     

Do We Have a Workable Clinical Protocol for Differentiating Lympho‐Hematopoietic Stem Cells from the Source of Embryonic Stem Cells and Induced Pluripotent Stem Cells in Culture?

In recent years, many researchers are focusing on deriving lympho‐hematopoietic stem cells (L‐HSC) from human embryonic stem cells (ESC) and/or induced pluripotent stem cells (iPSC) in culture as alternative sources for transplantation. Two protocols are available for research purposes: mouse stroma cell line coculture system and embryoid bodies (EBs) suspension culture system. However, due to the lack of human stroma cell line, which could support the derivation of L‐HSC in culture, the generation of therapeutic lympho‐hematopoietic cells for clinical purpose can only be achieved using EBs suspension culture system. In this short communication/review, the results of EBs suspension culture system using mouse and human ESC/iPSC are summarized and the potential clinical application is discussed.     

Esophageal Stem Cells—A Review of Their Identification and Characterization

The incidence of adenocarcinoma of the esophagus has increased faster than any other internal malignancy over the last 40 years. Despite this, surprisingly little is known about the basic biology of this tissue, particularly with regards to the organization of cell proliferation within the epithelium. This is a matter of crucial importance for our understanding of the pathogenesis of esophageal cancer. Nevertheless, significant advances have recently been made in the identification and functional characterization of both murine and human esophageal stem cells and their progeny in recent years. This places investigators in an exciting position to gain further insights into the processes of tissue renewal and repair on the one hand and the development of dysplasia and malignancy on the other. Wayne Phillips and Pritinder Kaur made equal contributions to this article.     

Mammary Stem Cells and Breast Cancer—Role of Notch Signalling

Adult stem cells are found in numerous tissues of the body and play a role in tissue development, replacement and repair. Evidence shows that breast stem cells are multipotent and can self renew, which are key characteristics of stem cells, and a single cell enriched with cell surface markers has the ability to grow a fully functional mammary gland in vivo. Many groups have extrapolated the cancer stem cell hypothesis from the haematopoietic system to solid cancers, where using in vitro culture techniques and in vivo transplant models have established evidence of cancer stem cells in colon, pancreas, prostate, brain and breast cancers. In the report we describe the evidence for breast cancer stem cells; studies consistently show that stem cell like and breast cancer initiating populations can be enriched using cell surface makers CD44⁺/CD24⁻ and have upregulated genes which include Notch. Notch signalling has been highlighted as a pathway involved in the development of the breast and is frequently dysregulated in invasive breast cancer. We have investigated the role of Notch in a pre-invasive breast lesion, ductal carcinoma in situ (DCIS), and have found that aberrant activation of Notch signalling is an early event in breast cancer. High expression of Notch 1 intracellular domain (NICD) in DCIS also predicted a reduced time to recurrence 5 years after surgery. Using a non-adherent sphere culture technique we have grown DCIS mammospheres from primary DCIS tissue, where self-renewal capacity, measured by the number of mammosphere initiating cells, were increased from normal breast tissue. A γ-secretase inhibitor, DAPT, which inhibits all four Notch receptors and a Notch 4 neutralising antibody were shown to reduce DCIS mammosphere formation, indicating that Notch signalling and other stem cell self-renewal pathways may represent novel therapeutic targets to prevent recurrence of pre-invasive and invasive breast cancer.     

Stem Cells in the Treatment of Cardiovascular Disease—An Overview

CVD irreversibly damage the cardiomyocytes, the heart muscle cells. This loss triggers a cascade of detrimental events, including formation of scar tissue, an overload of blood flow and pressure capacity, the overstretching of viable cardiac cells, leading to heart failure and eventual death. Restoring damaged heart muscle tissue, through repair or regeneration, is a potentially new strategy to treat heart failure and various other CVD. Stem cells are promising new therapeutics for patients with different heart diseases. The remarkable proliferative and differentiation capacity of stem cells promises an unlimited supply of specific cell types including viable functioning heart muscle cells. A crucial issue in designing more rational cell-based therapy approaches for cardiac disease is understanding the mechanisms by which each of the stem cell or progenitor-cell types can affect myocardial performance. This paper will highlight findings of multiple preliminary clinical experiments involving stem cells as therapeutics, educate the reader on the incidence and prevalence of CVD, the risk factors associated with CVD, and explore some of the challenges that can be encountered.     

The Involvment of Hematopoietic-Specific PLC -β2 in Homing and Engraftment of Hematopoietic Stem/Progenitor Cells

Migration and bone marrow (BM) homing of hematopoietic stem progenitor cells (HSPCs) is regulated by several signaling pathways, and here we provide evidence for the involvement in this process of hematopoietic-specific phospholipase C-β2 (PLC-β2). This enzyme is involved in release of intracellular calcium and activation of protein kinase C (PKC). Recently we reported that PLC-β2 promotes mobilization of HSPCs from BM into peripheral blood (PB), and this effect is mediated by the involvement of PLC-β2 in the release of proteolytic enzymes from granulocytes and its role in disintegration of membrane lipid rafts. Here we report that, besides the role of PLC-β2 in the release of HSPCs from BM niches, PLC-β2 regulates the migration of HSPCs in response to chemotactic gradients of BM homing factors, including SDF-1, S1P, C1P, and ATP. Specifically, HSPCs from PLC-β2-KO mice show impaired homing and engraftment in vivo after transplantation into lethally irradiated mice. This decrease in migration of HSPCs can be explained by impaired calcium release in PLC-β2-KO mice and a high baseline level of heme oxygenase 1 (HO-1), an enzyme that negatively regulates cell migration.     

Plasticity of Ectomesenchymal Stem Cells and its Ability of Producing Tissue Engineering Tooth by Recombining with Dental Epithelial Cells

1 IntroductionRecently, it has been found that human dental pulp stem cells could generate dentin-pulp complex-like structures in nude mice, but studies on tissue engineering tooth-like structures by cultured human dental epithelial and mesenchymal stem cells are still reported rarely. Ectomesenchyme is an unique structure of vertebrates embryo compose of postmigratory cephalic neural crest cells (NCC) and its derivatives. The aim of the present study was to identify and isolate the ectomesen…     

Effect of Transplantation of Neural Stem and Progenitor Cells on Memory in Animals with Alzheimer’s Type Neurodegeneration

Bulletin of Experimental Biology and Medicine - The effects of systemic and intracerebral transplantation of human fetal neural stem and progenitor cells were studied on the model of olfactory...     

Activated Hair Follicle Stem Cells and Wnt/β-catenin Signaling Involve in Pathnogenesis of Sebaceous Neoplasms

Sebaceous glands (SGs) undergo cyclic renewal independent of hair follicle stem cells (HFSCs) activation while HFSCs have the potential to differentiate into sebaceous gland cells, hair follicle and epidermal keratinocytes. Abnormalities of sebaceous gland progenitor cells contribute to the development of sebaceous neoplasms, but little is known about the role of HFSCs during sebaceous neoplasm development. Here, using dimethylbenzanthracene (DMBA) plus 12-o-tetradecanoyl phorbol-13-acetate (TPA) treatment developing sebaceous neoplasms (SNs) were identified with H&E and Oil red O staining. And then the molecular expression and activation of HFSCs and was characterized by immunostaining. Wnt10b/β-catenin signaling molecular which is important for activation of HFSCs were detected by immunostaining. We found hair follicle and epidermal cell markers were expressed in sebaceous neoplasms. Furthermore, SOX-9 and CD34-positive HFSCs were located in the basal layer of sebaceous lobules within the sebaceous neoplasms. Many appear to be in an active state. Finally, Wnt10b/β-catenin signaling was activated within the basal cells of sebaceous lobules in the sebaceous neoplasms. Collectively, our findings suggest that the abnormal activation of both HFSCs and Wnt10b/β-catenin signaling involves in the development of sebaceous neoplasms.     

The Regulatory Role of IFN-γ on the Proliferation and Differentiation of Hematopoietic Stem and Progenitor Cells

The replenishment of all blood cell lineages is hierarchically organized by the process of hematopoiesis, which is based on the differentiation pathways of hematopoietic stem and progenitor cells (HSPCs). Due to the ability to balance between self-renewal and differentiation, hematopoietic stem cells (HSCs) can generate the appropriate cell type that is required by the immune system and peripheral blood in response to physiological or pathological conditions. Numerous studies have shown that some proinflammatory cytokines contribute to the regulation of the various hematopoietic compartments. Of these, IFN-γ is a type II interferon primarily produced by T cells and natural killer cells, and plays a major role in the defense against invading pathogens and transformed cancer cells; moreover, a growing amount of research indicates that it exerts negative or positive regulatory effect on hematopoiesis. Although IFN-γ is a widely regarded negative regulator of HSC proliferation, it also participates in some chronic infections or hematological malignancies that induce bone marrow failure. Recent studies have demonstrated unexpected effects of IFN-γ, including the promotion of HSC formation and the stimulation of myelopoiesis. Here, we review the direct and indirect effects of IFN-γ on hematopoiesis, as well as the underlying signaling mechanisms of how IFN-γ modulates the self-renewal, cell cycle entry, and proliferation of HSCs. Next, we describe how IFN-γ affects different stages of the lineage differentiation from HSCs. Finally, we discuss the relationship between IFN-γ and compensatory extramedullary hematopoiesis, as well as some related clinical diseases.     

Expression of IL-10 and TNF-α in Rats with Cerebral Infarction after Transplantation with Mesenchymal Stem Cells

We investigated the effects of bone marrow-derived mesenchymal stem cells （MSCs） transplantation on the recovery of neurological functions in rat＇s MCAO （middle cerebral artery occlusion） model and its mechanism. MSCs were isolated from bone marrow of male Sprague Dawley （SD） rats. Female adult SD rats were randomly assigned into 4 groups： sham-operated group, MCAO group, vehicle group and MCAO ＋ MSCs-treated group. MSCs were injected into the lateral ventricle of rats in the MSCs-treated group and the same volume of PBS was given to the vehicle group. The expressions of IL-10 and TNF-α were assayed by RT-PCR and ELISA detections at day 1 and 4 after MCAO. The infarction volume was measured by TTC-staining. All rats underwent behavioral tests before, as well as 1, 4, and 14 days after MCAO. MSCs significantly improved functional recovery compared with the control at day 14 after transplantation. Compared with the MCAO group and the vehicle group, the expression of IL-10 mRNA and its protein level in the MSCs group significantly upregulated. However, the expression of TNF-α at day 4 after MCAO in the MSCs group significantly decreased compared with that of the MCAO group and the vehicle group. As a result, transplantation with MSCs significantly decreased infarct volume at day 1 and 4. This study strongly suggested transplantation with MSCs could reduce neuronal injury post focal cerebral ischemia in rats partly by regulating the expressions of IL-10 and TNF-α in the brain.     

Stem and Progenitor Cell Expansionin Co-culture of Mobilized CD34~ Cells and Osteopetrotic Mouse Stroma

1 IntroductionCulture systems capable of expanding and/or maintaining hematopoietic stem cells will not only facilitate our understanding of stem cell biology, but also broaden clinical applications. Among various in vitro hematopoietic culture systems, co-cultures of marrow or CD34~ cells with an adherent stromal layer that can produce cytokines and extracellular matrix components most effectively supports long-term hematopoiesis (LTC), mimicking the bone marrow micro-environment.The OP-9…     

Wharton’s Jelly Mesenchymal Stem Cells as Candidates for Beta Cells Regeneration: Extending the Differentiative and Immunomodulatory Benefits of Adult Mesenchymal Stem Cells for the Treatment of Type 1 Diabetes

Mesenchymal stem cells (MSC) are uniquely capable of crossing germinative layers borders (i.e. are able to differentiate towards ectoderm-, mesoderm- and endoderm-derived cytotypes) and are viewed as promising cells for regenerative medicine approaches in several diseases. Type I diabetes therapy should potentially benefit from such differentiated cells: the search for alternatives to organ/islet transplantation strategies via stem cells differentiation is an ongoing task, significant goals having been achieved in most experimental settings (e.g. insulin production and euglycaemia restoration), though caution is still needed to ensure safe and durable effects in vivo. MSC are obtainable in high numbers via ex vivo culture and can be differentiated towards insulin-producing cells (IPC). Moreover, recent reports evidenced that MSC possess immunomodulatory activities (acting on both innate and acquired immunity effectors) which should result in a reduction of the immunogenicity of transplanted cells, thus limiting rejection. Moreover it has been proposed that MSC administration should be used to attenuate the autoimmune processes which lead to the destruction of beta cells. This review illustrates the recent advances made in differentiating human MSC to IPC. In particular, we compare the effectiveness of the differentiation protocols applied, the markers and functional assays used to characterize differentiated progeny, and the in vivo controls. We further speculate on how MSC derived from Wharton’s jelly of human umbilical cord may represent a more promising regenerative medicine tool, as recently demonstrated for endoderm-derived organs (as liver) in human subjects, also considering their peculiar immunomodulatory features compared to other MSC populations.