Adipose Tissue ; cytology ; Heart ; physiology ; Humans ; Regeneration ; Stem Cells ; cytology

During mammalian development, migration, proliferation and survival of primordial germ cells can give rise to germ stem cells. There are evidences that stem cells also exist in adult gonad, and can maintain the renewal of germ cells and decelerate aging process. Therefore, germ stem cells play a pivotal role in rejuvenation of adult tissues as well as regeneration of damaged organs. Such cells have provided a potential resource for stem cell therapy and regenerative medicine.
Animals ; Cell Differentiation ; physiology ; Germ Cells ; cytology ; physiology ; Humans ; Stem Cells ; cytology ; physiology

Animals ; Cell Differentiation ; Fetus ; cytology ; Hematopoietic Stem Cells ; cytology ; Hepatocytes ; cytology ; Humans ; Liver ; cytology ; Stem Cells ; cytology ; physiology

Adult stem cells are drawing more and more attention due to the potential application in degenerative medicine without posing any moral problem. There is growing evidence showing that the human amnion contains various types of adult stem cell. Since amniotic tissue is readily available, it has the potential to be an important source of regenerative medicine material. In this study we tried to find multipotent adult stem cells in human amnion. We isolated stem cells from amniotic mesenchymal cells by limiting dilution assay. Similar to bone marrow derived mesenchymal stem cells, these cells displayed a fibroblast like appearance. They were positive for CD105, CD29, CD44, negative for haematopoietic (GlyA, CD31, CD34, CD45) and epithelial cell (pan-CK) markers. These stem cells had the potential to differentiate not only into osteogenic, adipogenic and endothelial lineages, but also hepatocyte-like cells and neural cells at the single-cell level depending on the culture conditions. They had the capacity for self-renewal and multilineage differentiation even after being expanded for more than 30 population doublings in vitro. So they may be an ideal stem cell source for inherited or degenerative diseases treatment.
Adult Stem Cells ; cytology ; Amnion ; cytology ; Cell Differentiation ; physiology ; Humans ; Mesenchymal Stromal Cells ; cytology ; Multipotent Stem Cells ; cytology

Male germ stem cells (mGSCs), which is in testis after sex differentiation, derive from primordial germ cells. In this study, bovine mGSCs were isolated from testis of 20 weeks fetuses. Number of CD9 positive cells of the cells through two-steps adhering plates velocity different was 95.8% by flow cytometer. The carina-type cells clones and the plane-type cells clones appeared in co-cultured system. One cells lines had been successively maintained for 4 passages, and the cells clusters showed AKP positive staining. The cells clusters showed nest-shape in third passage showed SSEA1 and Oct-4 positive staining. These cells can also spontaneously differentiate into c-kit positive staining germ cells, and the cells were directional induced to formaactin positive staining cardiac-like cells cluster and NF positive staining neuron-like cells. The conclusion showed that male germ stem cells from 20 weeks bovine fetuses could be in vitro formed like embryonic stem cells.
Animals ; Cattle ; Cell Differentiation ; physiology ; Cells, Cultured ; Embryonic Stem Cells ; cytology ; Fetus ; cytology ; Male ; Pluripotent Stem Cells ; cytology ; Spermatozoa ; cytology

At present, it is generally believed that the paracrine effect of stem cells in the repair of myocardial injury is one of the important ways for stem cell therapy. Exosomes are phospholipid bilayer-enclosed nanovesicles that secreted by cells under physiological and pathological conditions. Cargo loaded into exosomes including protein, lipids and nucleic acids can be delivered to recipient cells. Therefore, exosomes are recognized as important mediators for intercellular communication. It has been suggested that exosomes from stem cells (eg. embryonic stem cells, induced pluripotent stem cells, cardiac progenitor cells, mesenchymal stem cells and cardiosphere-derived cells) have protective effects against heart injury. In this review, we summarized recent research progresses on stem cell-derived exosomes in myocardial injury, including the therapeutic effects and mechanism.
Cell Communication ; Exosomes ; physiology ; Heart Injuries ; Humans ; Induced Pluripotent Stem Cells ; cytology ; Mesenchymal Stem Cells ; cytology

Hematopoietic stem cell transplantation (HSCT) is an important mean for clinical treatment to many of hematological diseases, malignant diseases, hereditary diseases and autoimmune diseases. Whether the implanted hematopoietic stem cells (HSC) can home to bone marrow (BM) smoothly and reconstitute the hematopoiesis is the key to successful HSCT. With the cognition of HSC homing mechanism, the visual observation of HSC homing to BM is attracting more and more attention and helps to clarify the micro-dialogue between HSC and BM microenvironment. In recent years, with the development of imaging technology, confocal laser scanning microscope (CLSM) and two-photon microscope are able to make 3D reconstruction and real-time observation of the tissue or cells. Researches on HSC homing process visibly become reality. In this article the methods of visual research and their application in HSC homing observation are reviewed.
Cell Movement ; Hematopoiesis ; physiology ; Hematopoietic Stem Cells ; cytology ; physiology ; Humans ; Stem Cell Niche ; physiology

OBJECTIVETo identify the localization of hair follicles stem cell (HFSC) in different stages of hair and explore the differentiating capacity of HFSC into epidermis in vitro.

METHODSHFSC were detected by K19 immunostaining in normal human skin. Then, the isolated HFSC through enzyme digestion were seeded on dermal equivalent (DE) and cultured between the air-liquid interfaces for 14 days. Skin-equivalents was harvested and used for evaluation.

RESULTSHFSC mainly located in outer root sheet in hair follicle and human anagen hair follicles containing two distinct reservoirs for K19-positive cells located in the bulge and bulb of the follicle. These two reservoirs fused in line of outer root sheets during the catagen-telogen transition phase and individualized again in the newly forming anagen hair follicle. Based on DE, growing HFSC built a multilayered and confined epidermis.

CONCLUSIONHFSC located in outer root sheets can promote hair cycle and differentiate into epidermis in vitro.

Cell Differentiation ; physiology ; Cells, Cultured ; Epidermis ; cytology ; Hair Follicle ; cytology ; Humans ; Stem Cells ; cytology

Hematopoietic stem cells (HSCs) are tissue specific stem cells that replenish all mature blood lineages during the lifetime of an individual. Hematopoietic cell clusters in the aorta of vertebrate embryos play a pivotal role in the formation of the adult blood system. Recently, people have learned a lot about the embryonic HSCs on their development and homing. During their differentiation, HSCs are regulated by the transcription factors, such as Runx1 and Notch signaling pathway, etc. MicroRNAs also regulate the self-renewal and differentiation of hematopoietic stem/progenitor cells on the post-transcriptional levels. Since the onset of circulation, the formation of HSCs and their differentiation into blood cells, especially red blood cells, are regulated by the hemodynamic forces. It would be of great significance if we could treat hematologic diseases with induced HSCs in vitro on the basis of fully understanding of hemotopoietic stem cell development. This review is focused on the advances in the research of HSCs' development and regulation.
Blood Cells ; cytology ; Cell Differentiation ; Embryonic Stem Cells ; cytology ; Hematopoietic Stem Cells ; cytology ; Humans ; Signal Transduction ; Transcription Factors ; physiology

Recent studies have confirmed that diverse adult tissue cells can be reprogrammed and induced to pluripotency, that is so-called induced pluripotent stem cells (iPS cells). But most of these dedifferentiated processes are induced by gene delivery with retroviral vectors. Some of the delivered genes are cancer causing. So, in current situation, these adult-derived embryonic stem-like cells cannot be used in clinical therapy to cure human diseases. Recently some articles that were published in the authoritative journals are receiving attentions. They show that, in mice and human, spermatogonial stem cells (SSCs) can be used for generating pluripotent stem cells without the exogenous genes and retroviruses, and they can also be used for autologous transplantation without ethical problems. These findings suggest that human SSCs may have considerable potential for cell-based, autologous organ regeneration therapy for various diseases. In this review, we describe and compare the methods that have been used to isolate, purificate and culture SSCs. We also describe the recent results in which SSCs can be transformed into pluripotent stem cells, and the pluripotent stem cells have potential applications in regenerative medicine and genetic medicine.
Cell Culture Techniques ; methods ; Cell Dedifferentiation ; physiology ; Cells, Cultured ; Humans ; Male ; Pluripotent Stem Cells ; cytology ; Spermatogonia ; cytology ; Stem Cells ; cytology