Stem cell research is a innovative technology that focuses on using undifferentiated cells able to self-renew through the asymmetrical or symmetrical divisions. Three types of stem cells have been studied in laboratory including embryonic stem cell, adult stem cells and induced pluripotent stem cells. Embryonic stem cells are pluripotent stem cells derived from the inner cell mass and it can give rise to any fetal or adult cell type. Adult stem cells are multipotent, have the ability to differentiate into a limited number of specialized cell types, and have been obtained from the bone marrow, umbilical cord blood, placenta and adipose tissue. Stem cell therapy is the most promising therapy for several degenerative and devastating diseases including digestive tract disease such as liver failure, inflammatory bowel disease, Celiac sprue, and pancreatitis. Further understanding of biological properties of stem cells will lead to safe and successful stem cell therapies.
Adult Stem Cells/cytology/metabolism/transplantation ; Embryonic Stem Cells/cytology/metabolism/transplantation ; Humans ; Induced Pluripotent Stem Cells/cytology/metabolism/transplantation ; Stem Cells/*cytology/metabolism

Adult stem cells are the multi-potential cells, which exist in fetal and adult tissues. It can reproduce itself (undergo self-renewal) or give rise to more specialized (differentiated) cells. Under certain inducing conditions, adult stem cells can acquire the ability to differentiate into different tissue cells. Multipotent adult progenitor cells (MAPC), an alternative name of adult stem cell given by Catherine Verfaillie, existing in bone marrow, can differentiate into cells with characteristics of mesodermal, neuroectodermal, and endodermal lineages in vitro at the single-cell level. MAPC can also contribute to most cell types when injected into the blastocyst. Adult stem cell differentiation implies that different cell lineages are derived from a single initial cell; all differentiated cell types are functional in vitro and in vivo; and engraftment is robust and persistent in the physiological and pathological situations. The possible mechanisms may underlie the differentiation: various tissue-specific stem cells are present in different organs; adult stem cells would be reprogrammed when removed from their usual microenvironment and introduced into a different niche that imparts signals to activate a novel genetic program needed for the new cell fate. And true multi-potential stem cells persist in postnatal life. In the future, multi-potent adult stem cells might then be used for therapies of degenerative or genetic disorders of multiple different organs.
Adult Stem Cells ; cytology ; Cell Differentiation ; Humans ; Multipotent Stem Cells ; cytology ; Stem Cell Transplantation

Spermatogonial stem cells (SSCs) play an important role in spermatogenesis and have a unique mode of replication. A single SSC can produce two differentiating cells, or one stem cell and one differentiating cell. The self-renewal and differentiation of SSCs are precisely regulated as relating the niche of SSCs, glial cell line-derived neurotrophic factor, and several signaling pathways. This article reviews the self-renewal and differentiation of SSCs and their regulation mechanisms, which may offer a deeper insight into spermatogenesis and male infertility and pave a theoretical ground for studying testicular tumorigenesis and searching for new potential approaches to the treatment of testicular cancer and other related diseases.
Adult Stem Cells ; cytology ; Cell Differentiation ; Cells, Cultured ; Humans ; Male ; Spermatogenesis ; Spermatogonia ; cytology ; Stem Cell Transplantation

The study on stem cells is a hot field in biomedical science in recent years, and has furthered from laboratory to clinical application. Stem cells, according to their developmental stage and differential properties, can be divided into embryonic stem cells, induced PS cells and adult stem cells, among which, adult stem cells have already been applied to the clinical treatment of many systemic diseases. Currently, the study of spermatogonial stem cells and adult stem cells is in the front of the basic researches on the treatment of male infertility, but the time has not yet arrived for their clinical application. This paper outlines the application prospect of adult stem cells in male infertility.
Adult Stem Cells ; cytology ; Humans ; Infertility, Male ; therapy ; Male ; Mesenchymal Stromal Cells ; cytology ; Spermatogonia ; cytology ; Stem Cell Transplantation

All of neural stem cell within the central nervous system and derived from transplantation or embryonic stem cell have the ability of differentiating into various kinds of neural cells. Regeneration of neural cells plays a critical role on function recovery damaged central nervous system (CNS). Advances in repairing of injury in central nervous system with neural stem cell and embryonic stem cell in recent years are reviewed in this article.
Adult Stem Cells ; cytology ; Animals ; Central Nervous System Diseases ; physiopathology ; surgery ; Embryonic Stem Cells ; cytology ; Humans ; Nerve Regeneration ; physiology ; Neuronal Plasticity ; Neurons ; cytology ; Stem Cell Transplantation

OBJECTIVEThe culture of human spermatogonial stem cells (SSC) has not been studied in detail yet. Here we tried to explore the optimized culture method of human SSC by using several different co-culture systems.

METHODSThe alpha6 +Thy-1 +c-kit- cells acquired by the immunomagnetic beads sorting technique were cultured in different co-culture systems. Their morphological, biological characteristics and survival rates were intensively observed by microscopic or immunocytochemical assay. The long-term survival rate of human SSC during culture period was evaluated by germ cell transplantation technique.

RESULTSThe alpha6 +Thy-1 +c-kit- cells could stably survive in the DMEM and DMEM/F12 mediums with fetal bovine serum (FBS) on feeder layer. The survival rates within 1 week were more than 90%. The long-time culture showed the cells were gradually attached on the surface of Sertoli cells by the manner of scattered single cell or accumulated masses. Part of the SSC became more tightly attachment with Sertoli cells or mounted among the Sertoli cells. They could survive or even proliferate for more than 3 months in vitro. Germ cells transplantation study showed that some alpha6 +Thy-1 +c-kit- cells labeled by PKH26 could resided on the basal membrane of seminiferous tubule of nude mice, appearing as single or coupled cells 2 months later after transplantation. The function evaluation of the cultured cells by counting the fluorescent cells in the seminiferous tubule showed 54.9% and 9.2% of SSC in the alpha6 +Thy-1 +c-kit- cells were still remained after cultured for 2 and 4 weeks, respectively.

CONCLUSIONHuman SSC could maintain survival in vitro for more than 3 months, but it was still need to seek for a more optimized and successful culture system for its efficient expansion and proliferation. Thus it will open up a wide prospect for the understanding of the biology of human SSC and the treatment of male sterility.

Adult ; Cell Culture Techniques ; Cell Survival ; Cells, Cultured ; Coculture Techniques ; Humans ; Male ; Sertoli Cells ; cytology ; Spermatogonia ; cytology ; physiology ; Stem Cell Transplantation ; Stem Cells ; cytology

Neurogenesis occurs in the adult brain, and neural stem cells (NSCs) reside in the adult central nervous system (CNS). In the adult brain, newly generated neuronal cells would originate from a population of glial cells with stem cells properties, and be involved in processes such as learning and memory, depression, and in regenerative attempts in the diseased brain and after injuries. In human, a recent study reported no evidence of migrating neural progenitor cells along the subventricular zone (SVZ) to the olfactory bulb (OB), contrary to other species, highlighting the particularity of adult neurogenesis in human. Though the origin and contribution of newly generated neuronal cells to CNS pathophysiology remain to be fully understood, the discovery that NSCs reside in the adult CNS force us to re-evaluate our knowledge and understanding of brain functioning, and suggest that the adult CNS may be amenable to repair. In this manuscript,we will review the recent data, debates and controversies on the identification, origin and function of newly generated neuronal cells in the adult brain, in human and in other species. We will discuss their contribution and significance to CNS pathophysiology, and for cellular therapy.
Adult Stem Cells ; cytology ; transplantation ; Aging ; Animals ; Brain ; cytology ; Central Nervous System ; cytology ; growth & development ; Central Nervous System Diseases ; pathology ; surgery ; Humans ; Stem Cell Transplantation ; methods

Diabetes mellitus is a metabolic diseases, mainly including type 1 and type 2 diabetes. Treatment for type 1 and part of type 2 often involves regular insulin injection. However, this treatment neither precisely controls the blood sugar levels, nor prevents the diabetes complications. Transplantation of islets of Langerhans offers an attractive strategy for diabetes therapies, but its wide application has been limited by donor shortage and immunological rejection after transplantation. Stem cells with strong proliferation capacity and multipotential may be potential cell sources in diabetes therapies. For this, adult stem cells are interesting because of absence of teratoma formation and ethnical problems. Adult pancreatic stem cells (PSCs) really exist and could produce insulin-secreting cells both under the condition of pancreatic injury and in vitro culture, but lack of effective markers to enrich PSCs hampers the studies of exploring the expanding and differentiating conditions in vitro. Some other adult stem cells, such as hepatic stem cells, marrow stem cells or intestine stem cells, were also suggested to transdifferentiate into insulin-producing cells under special culture conditions in vitro or by genetic modifications. Moreover, transplanting these adult stem cells-derived insulin-secreting cells into the diabetic mouse could cure diabetes. Thus, adult stem cells would supply the abundant beta-cell sources for cell replacement therapy of diabetes.
Adult Stem Cells ; cytology ; transplantation ; Animals ; Cell Culture Techniques ; Cell Differentiation ; Diabetes Mellitus ; therapy ; Insulin-Secreting Cells ; cytology

OBJECTIVETo evaluate the clinical effect of cell-assisted lipotransfer (CAL) for breast augmentation.

METHODS18 patients accepted breast augmentation using CAL. 10 patients completed 6-month follow-up and were involved in the study. The adipose tissue was harvested from patients' thighs, flanks and lower abdomen with Lipokit. After standing, 250 ml fatty portion and 500 ml fluid portion of suction aspirates were processed according to the procedures reported in reference. Flow-cytometry was used to detect the percentage of adipose-derived stem cells(ADSCs) in distilled stromal vascular fraction (SVF). The differentiation function of cultured cells also was assessed. The breast volume and images were evaluated by using MRI before operation, 3 and 6 months after operation. The breast volume was marked as V0, V3 and V6 respectively. The resorption rate of transplanted adipose tissue for each breast was calculated and marked as R3 and R6.

RESULTSAveragely, the percentage of ADSCs in freshly distilled SVF was 41.67%. The in-vitro cultured cell grew well and could differentiate into fat, bone and cartilage. Statistics showed that V0, V3 and V6 was (416.19 +/- 40.43) ml, (551.72 +/- 59.86) ml and (538.81 +/- 68.35) ml respectively. R3 and R6 was (51.20 +/- 11.96)% and (54.22 +/- 12.73)%. There was significant difference between V3 and V0 (P < 0.05), V6 and V0. However, no significant difference was showed between V3 and V6 or R3 and R6. In addition, no cyst or calcification was seen in all MRI images.

CONCLUSIONSIn process of breast augmentation using CAL, the distilled SVF contains 41.67% ADSCs which have adipogenic, osteogenic and chondrogenic function. Within 3-month post-operation, the breast volume decreases obviously but the volume sustains after that. Compared with the preoperative volume, the 6-month postoperative volume is significantly increased and the breasts' contour is improved greatly. This study indicates that CAL is a safe and effective way for breast augmentation.

Adipocytes ; cytology ; transplantation ; Adipose Tissue ; cytology ; Adult ; Cell Differentiation ; Cells, Cultured ; Female ; Humans ; Mammaplasty ; methods ; Middle Aged ; Stem Cell Transplantation ; Stromal Cells ; cytology

Adult stem cells are multipotent and self-renewing cells that contain several functions; i) migration and homing potential: stem cells can migrate to injured and inflamed tissues. ii) differentiation potential: stem cells which migrated to injured tissues can be differentiated into multiple cell types for repairing and regenerating the tissues. iii) immunomodulatory properties: stem cells, especially mesenchymal stem cells can suppress immune system such as inflammation. All those characteristics might be useful for the treatment of the digestive tract diseases which are complex and encompass a broad spectrum of different pathogenesis. Preclinical stem cell therapy showed some promising results, especially in liver failure, pancreatitis, sepsis, and inflammatory bowel disease. If we can understand more about the mechanism of stem cell action, stem cell therapy can become a promising alternative treatment for refractory digestive disease in the near future. In this review, we summarized current preclinical experiences in diseases of the digestive tract using stem cells.
Adult Stem Cells/cytology/*transplantation ; Digestive System Diseases/*therapy ; Drug Evaluation, Preclinical ; Humans