Three‐dimensional Co‐culture of hepatic progenitor cells and mesenchymal stem cells in vitro and in vivo

Introduction: Here we co‐cultured hepatic progenitor cells (HPCs) and mesenchymal stem cells (MSCs) to investigate whether the co‐culture environments could increase hepatocytes form. Methods: Three‐dimensional (3D) co‐culture model of HPCs and MSCs was developed and morphological features of cells were continuously observed. Hepatocyte specific markers Pou5f1/Oct4, AFP, CK‐18 and Alb were analyzed to confirm the differentiation of HPCs. The mRNA expression of CK‐18 and Alb was analyzed by RT‐PCR to investigate the influence of co‐culture model to the terminal differentiation process of mature hepatocytes. The functional properties of hepatocyte‐like cells were detected by continuously monitoring the albumin secretion using Gaussia luciferase assays. Scaffolds with HPCs and MSCs were implanted into nude mouse subcutaneously to set up the in vivo co‐culture model. Results: Although two groups formed smooth spheroids and high expressed of CK‐18 and Alb, hybrid spheroids had more regular structures and higher cell density. CK‐18 and Alb mRNA were at a relatively higher expression level in co‐culture system during the whole cultivation time (P < 0.05). Albumin secretion rates in the hybrid spheroids had been consistently higher than that in the mono‐culture spheroids (P < 0.05). In vivo, the hepatocyte‐like cells were consistent with the morphological features of mature hepatocytes and more well‐differentiated hepatocyte‐like cells were observed in the co‐culture group. Conclusions: HPCs and MSCs co‐culture system is an efficient way to form well‐differentiated hepatocyte‐like cells, hence, may be helpful to the cell therapy of hepatic tissues and alleviate the problem of hepatocytes shortage. Microsc. Res. Tech. 78:688–696, 2015. © 2015 Wiley Periodicals, Inc.     

Embryonic erythropoiesis in human yolk sac: two different compartments for two different processes

The wall of 12 yolk sacs (YSs) from 17- to 50-day-old human embryos was examined by light, scanning, and transmission electron microscopy to identify the ontogeny of embryonic erythropoiesis. Initial formation of blood island with the generation of erythroid and endothelial cells was seen in the mesenchymal layer in embryos aged 17 days. A network of blood vessels containing abundant erythroblasts was identified in the YS walls of embryos aged approximately 24 days. At this age, erythroblasts were also identified within the embryo body. Primitive erythroblasts were the only cells present within the embryo and its YS until the end of week 5. These cells first appeared in the mesenchymal vascular plexus of the YS wall, and were then observed in the liver and other tissues of the embryo. At embryonic week 5, two compartments were identified in the YS wall; a mesodermal one in which blood vessels were formed, and an endodermal compartment in which erythrocytes were present within the endodermal vesicles. Erythrocytes were small non-nucleated cells similar to adult erythrocytes. Transmission electron microscopic observation focused on the endodermal vesicles confirmed the presence of definitive erythrocytes only at such extra vascular location. At this age, there were no definitive erythrocytes detected within the embryo. Erythrocytes started to be identified in embryonic blood vessels from week 7 onward. These findings provide information not previously described about YS erythropoiesis during early human development.     

The effects of human menstrual blood stem cells‐derived granulosa cells on ovarian follicle formation in a rat model of premature ovarian failure

Many studies have reported that human endometrial mesenchymal stem cells (HuMenSCs) are capable of repairing damaged tissues. The aim of the present study was to investigate the effects of HuMenSCs transplantation as a treatment modality in premature ovarian failure (POF) associated with chemotherapy‐induced ovarian damage. HuMenSCs were isolated from menstrual blood samples of five women. After the in vitro culture of HuMenSCs, purity of the cells was assessed by cytometry using CD44, CD90, CD34, and CD45 FITC conjugate antibody. Twenty‐four female Wistar rats were randomly divided into four groups: negative control, positive control, sham, and treatment groups. The rat models of POF used in our study were established by injecting busulfan intraperitoneally into the rats during the first estrus cycle. HuMenSCs were transplanted by injection via the tail vein into the POF‐induced rats. Four weeks after POF induction, ovaries were collected and the levels of Amh, Fst, and Fshr expression in the granulosa cell (GC) layer, as well as plasma estradiol (E2) and progesterone (P4) levels were evaluated. Moreover, migration and localization of DiI‐labeled HuMenSCs were detected, and the labeled cells were found to be localized in GCs layer of immature follicles. In addition to DiI‐labelled HuMenSCs tracking, increased levels of expression of Amh and Fshr and Fst, and the high plasma levels of E2 and P4 confirmed that HuMenSC transplantation had a significant effect on follicle formation and ovulation in the treatment group compared with the negative control (POF) group.     

Ultrastructural evaluation of mesenchymal stem cells from inflamed periodontium in different in vitro conditions

This research aimed to observe the behavior of mesenchymal stem cells (MSCs) isolated from periodontal granulation tissue (gt) when manipulated ex vivo to induce three‐dimensional (3D) spheroid (aggregates) formation as well as when seeded on two bone scaffolds of animal origin. Periodontal gt was chosen as a MSC source because of its availability, considering that it is eliminated as a waste material during conventional surgical therapies. 3D aggregates of cells were generated; they were grown for 3 and 7 days, respectively, and then prepared for transmission electron microscopic analysis. The two biomaterials were seeded for 72 h with gtMSCs and prepared for scanning electronic microscopic observation. The ultrastructural analysis of 3D spheroids remarked some differences between the inner and the outer cell layers, with a certain commitment observed at the inner cells. Both scaffolds showed a relatively smooth surface at low magnification. Macro‐ and micropores having a scarce distribution were observed on both bone substitutes. gtMSCs grew with relative difficulty on the biomaterials. After 72 h of proliferation, gtMSCs scarcely covered the surface of bovine bone scaffolds, demonstrating fibroblast‐like or star‐like shapes with elongated filiform extensions. Our results add other data on the possible usefulness of gtMSC and could question the current paradigm regarding the complete removal of chronically inflamed gts from the defects during periodontal surgeries. Until optimal protocols for ex vivo manipulation of MSCs are available for clinical settings, it is advisable to use biocompatible bone substitutes that allow the development of progenitor cells. Microsc. Res. Tech. 78:792–800, 2015. © 2015 Wiley Periodicals, Inc.     

Regeneration of spines and pedicellariae in echinoderms: a review.

Morphogenesis of tissues during regeneration of echinoderm spines and pedicellariae is reviewed. Regeneration of the skeleton is rather well documented while that of associated soft tissues is poorly investigated. In particular, little information is available on the early regeneration stages which follow wound healing. From the available information, it is suggested that regeneration of broken spines proceeds through a morphallactic process of which the organizational information, as well as the involved cells, lies in the stump. In contrast, regeneration of removed spines and pedicellariae may depend on an epimorphic process whose organizational information could be located in the mutable connective tissue that joins the appendage to the main body wall.     

Correlative scanning electron and confocal microscopy imaging of labeled cells coated by indium‐tin‐oxide

Confocal microscopy imaging of cells allows to visualize the presence of specific antigens by using fluorescent tags or fluorescent proteins, with resolution of few hundreds of nanometers, providing their localization in a large field‐of‐view and the understanding of their cellular function. Conversely, in scanning electron microscopy (SEM), the surface morphology of cells is imaged down to nanometer scale using secondary electrons. Combining both imaging techniques have brought to the correlative light and electron microscopy, contributing to investigate the existing relationships between biological surface structures and functions. Furthermore, in SEM, backscattered electrons (BSE) can image local compositional differences, like those due to nanosized gold particles labeling cellular surface antigens. To perform SEM imaging of cells, they could be grown on conducting substrates, but obtaining images of limited quality. Alternatively, they could be rendered electrically conductive, coating them with a thin metal layer. However, when BSE are collected to detect gold‐labeled surface antigens, heavy metals cannot be used as coating material, as they would mask the BSE signal produced by the markers. Cell surface could be then coated with a thin layer of chromium, but this results in a loss of conductivity due to the fast chromium oxidation, if the samples come in contact with air. In order to overcome these major limitations, a thin layer of indium‐tin‐oxide was deposited by ion‐sputtering on gold‐decorated HeLa cells and neurons. Indium‐tin‐oxide was able to provide stable electrical conductivity and preservation of the BSE signal coming from the gold‐conjugated markers. Microsc. Res. Tech. 78:433–443, 2015. © 2015 Wiley Periodicals, Inc.     

Ultrastructural analysis of murine hippocampal neural progenitor cells in culture

Despite the great number of studies devoted to neural stem/progenitor cell biology, the ultrastructural characteristics of these cells in vitro have not been fully studied. To determine the fine structure of hippocampal neural progenitor cells (NPCs) in culture, mouse fetal hippocampi (E18) were extracted, dissected, and cells were expanded as adherent monolayer culture. Electron microscopy revealed that NPCs had an immature phenotype, with a high nuclear/cytoplasmic ratio, small and scant organelles, underdeveloped endoplasmic reticulum, and many free ribosomes and polysomes. Our results may contribute to a better understanding of the fine structure and physiology of hippocampal NPCs in vitro. Microsc. Res. Tech. 78:128–133, 2015. © 2014 Wiley Periodicals, Inc.     

Role of spermatogonial stem cells extract in transdifferentiation of 5‐Aza‐2′‐deoxycytidine‐treated bone marrow mesenchymal stem cells into germ‐like cells

As one of the induced pluripotent stem cells (iPSCs) methods, spermatogonial stem cells (SSC_S) extract is considered as new approach in stem cell therapy of infertility. 5‐aza‐2′‐deoxycytidine (5‐aza‐dC) inhibits methyltransferase enzyme, and induces gene reprogramming; herein, the effects of SSC_S extract incubation in 5‐aza‐dC‐treated bone marrow mesenchymal stem cells (BMMSCs) has been surveyed. BMMSCs were isolated from femurs of three to four weeks old male NMRI mice, and the cells at passage three were treated with 2 µM 5‐aza‐dC for 72 hours. SSCs were isolated, cultured, and harvested at passage three to collect SSC_S extract; BMMSCs were then incubated with SSC_S extract in the three time periods: 72 hours, one week and two weeks. There were five groups: control, sham, extract, 5‐aza‐dC and extract‐5‐aza‐dC. After one week of incubation, flow cytometry and real‐time polymerase chain reaction (PCR) exhibited high levels of expression for β1‐ and α6‐integrins and promyelocytic leukaemia zinc finger (PLZF) in extract and extract‐5‐aza‐dC groups (P < 0.05 vs. control and 5‐aza‐dC), and cells in these two groups had two forms of morphology, round and fusiform, similar to germ‐like cells. 5‐aza‐dC had no significant effects during the three time periods of evaluation. These data disclose the effectiveness of SSCs extract incubation in transdifferentiation of BMMSCs into germ‐like cells; this strategy could introduce a new approach for treatment of male infertility in clinic. Microsc. Res. Tech. 79:365–373, 2016. © 2016 Wiley Periodicals, Inc.     

Visualization of BrdU-labelled DNA in cyanobacterial cells by Hilbert differential contrast transmission electron microscopy

We have attempted to observe the native shape of DNA in rapidly frozen whole cyanobacterial cells through 5-bromo-2-deoxyuridine (BrdU) incorporation and visualization with a Hilbert differential contrast transmission electron microscopy (HDC TEM). The incorporation of BrdU into the DNA of Synechococcus elongatus PCC 7942 was confirmed with fluorescently labelled anti-BrdU antibodies and through EDX analysis of ultra-thin sections. HDC TEM observed cells that had incorporated BrdU into their DNA exhibited electron dense areas at the location corresponding to fluorescently labelled BrdU. Since various strings and strands were observed in high contrast with the HDC TEM, we conclude that the method promises to allow us to identify and understand bulk structural changes of the in vivo DNA and the nucleoid through observation at high resolution.     

MRT Letter: 3D culture of isolated cells: A fast and efficient method for optimizing their histochemical and immunocytochemical analyses

The rapid development of three‐dimensional (3D) culture systems and engineered cell‐based tissue models gave rise to an increasing need of new techniques, allowing the microscopic observation of cell behavior/morphology in tissue‐like structures, as clearly signalled by several authors during the last decennium. With samples consisting of small aggregates of isolated cells grown in suspension, it is often difficult to produce an optimal embedded preparation that can be further successfully processed for classical histochemical investigations. In this work, we describe a new, easy to use, efficient method that enables to embed an enriched “preparation” of isolated cells/small 3D cell aggregates, without any cell stress or damage. As for after tissue‐embedding procedures, the cellular blocks can be further suitably processed for efficient histochemical as well as immunohistochemical analyses, rendering more informative‐and attractive‐studies onto 3D cell‐based culture of neo‐tissues. Microsc. Res. Tech. 78:249–254, 2015. © 2015 Wiley Periodicals, Inc.     

Immunohistochemical and lectin histochemical studies on the developing olfactory organs of fetal camel

Little is known about the development of the olfactory organs of camel. In this study, prenatal development and neuronal differentiation of the vomeronasal organ (VNO) and the olfactory epithelium (OE) of the one‐humped camel were studied by immunohistochemistry and lectin histochemistry. A neuronal marker, protein gene product (PGP) 9.5, but not a marker of fully differentiated olfactory receptor cells, olfactory marker protein, intensely labeled the olfactory receptor cells of the VNO and OE at 395 mm, 510 mm, and 530 mm fetal ages, indicating that the olfactory receptor cells are differentiated, but not fully matured both in the VNO and the OE. In 187 mm and 190 mm fetuses, PGP 9.5 yielded faint immunoreactive signals in the VNO, but not in the OE, although the presence of olfactory receptor cells were demonstrated in both tissues by intense WGA and LEL stainings. We conclude that the camel VNO and OE bear differentiated, but still immature receptor cells; in addition, the onset of neuronal differentiation seems to be somewhat earlier in the VNO than in the OE till half of the prenatal life. Microsc. Res. Tech. 78:613–619, 2015. © 2015 Wiley Periodicals, Inc.     

Visualization of interstitial cells of Cajal in living, intact tissues

Interstitial cells of Cajal (ICC) appear to be a major element in pacing and signal transmission in the gastrointestinal tract. A prominent problem in the study of ICC has been the difficulty in observing them in intact tissues. We used several methods to visualize living ICC in freshly-dissected tissues: (1) Placing small crystals of the lipophilic dye DiI in the submucosal-circular muscle border in the mouse colon resulted in the labeling of living ICC-like cells. Two main morphological cell types, bipolar and multipolar, were noted. The DiI stain could be converted into a stable, electron-opaque product. Electron-microscopic observations showed that the labeled cells had the typical appearance of ICC reported in previous studies. (2) Living ICC in the region of the myenteric plexus (ICC-MP) in the small intestines of mice and guinea-pigs were observed with Nomarski optics. This enabled the visualization of ICC in living tissues, and the impalement of the cells with Lucifer yellow-filled microelectrodes. The dye-labeled cells had the morphological features of ICC-MP, and about 30% of them were found to be dye coupled to 1-21 other ICC. The identity of the cells as ICC was verified by electron-microscopy following photoconversion, and by c-kit immunohistochemistry. (3) Living ICC were labeled with a c-kit antibody that does not require tissue fixation. This resulted in the fluorescent staining of the entire ICC network. Single cells were labeled by dye injection, which provided a detailed picture of ICC morphology. This method was found to be suitable for a wide range of tissues. We expect that these three methods for identifying ICC in intact, living tissues will be useful for physiological and pharmacological investigations of ICC in a variety of gastrointestinal tissues.     

Periodontal regeneration: a challenge for the tissue engineer?

Periodontitis affects around 15 per cent of human adult populations. While periodontal treatment aimed at removing the bacterial cause of the disease is generally very successful, the ability predictably to regenerate the damaged tissues remains a major unmet objective for new treatment strategies. Existing treatments include the use of space-maintaining barrier membranes (guided tissue regeneration), use of graft materials, and application of bioactive molecules to induce regeneration, but their overall effects are relatively modest and restricted in application. The periodontal ligament is rich in mesenchymal stem cells, and the understanding of the signalling molecules that may regulate their differentation has increased enormously in recent years. Applying these principles for the development of new tissue engineering strategies for periodontal regeneration will require further work to determine the efficacy of current experimental preclinical treatments, including pharmacological application of growth factors such as bone morphogenetic proteins (BMPs) or Wnts, use of autologous stem cell reimplantation strategies, and development of improved biomaterial scaffolds. This article describes the background to this problem, addresses the current status of periodontal regeneration, including the background biology, and discusses the potential for some of these experimental therapies to achieve the goal of clinically predictable periodontal regeneration.     

Hematopoietic progenitor constituents and adherent cell progenitor morphology isolated from black-rumped agouti (Dasyprocta prymnolopha, Wagler 1831) bone marrow

Stem cells are present in the adult tissues of most diverse species. Bone marrow is recognized to be the most exploited site to obtain stem cells and cell progenitors. The objective of the present study was to characterize hematopoietic progenitor (HP) morphology and analyze the performance of adherent cell progenitors (ACPs) cultivated in vitro from black‐rumped agouti bone marrow (Dasyprocta prymnolopha). Bone marrow aspirates were obtained from tibia crest and used to prepare histological slides and identify cell morphology. Cells were also scattered on culture plates for later isolation, expansion, and quantification. Smears obtained from bone marrow demonstrated HPs at different stages of maturity. In culture, these cells showed fibroblastoid morphology and a strong tendency to form colonies, demonstrated by the presence of cell aggregates, cytoplasmic elongations lying side by side. An 80% cell confluence was observed at 18 days in culture and progressive reduction in the percentage of nonadherent mononuclear cells. After eight passes, a mean cell viability of 96.07% was observed, from a pool of 1.6 × 10⁷ cells (ACP). Thirteen 25‐cm² culture bottles were trypsinized, resuspended in freezing medium, stored in 14 criotubes at a concentration of 1 × 10⁶ cells per milliliter, and placed in liquid nitrogen at ?196°C. Agouti bone marrow demonstrated high plasticity, moreover different HP lines, and a population of adherent cells demonstrated morphology similar to mesenchymal stem cells in culture. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Re-evaluation of nestin as a marker of oligodendrocyte lineage cells

Maturation of oligodendrocyte progenitors (O2A) is characterized by morphological changes and the sequential expression of specific antigens leading to the formation of myelin membrane. Monoclonal antibodies A2B5, A007, anti-vimentin, and anti-galactocerebroside, recognize oligodendroglia at different stages of development. The neuroepithelial precursor marker nestin is also expressed by the oligodendroglial lineage; we have used enriched populations of progenitors isolated from neonatal rat brain cultures to further examine the cellular distribution of this intermediate filament protein. The phenotypic distribution of nestin positive cells among the oligodendrocyte lineage showed that 65% reacted with A2B5, whereas only 5% were A007(+), and 4% galactocerebroside(+). The remaining 25% of the cells were not labeled and had small cellular bodies devoid of processes, characteristic of the pre-O2A progenitor. Further analysis of the nestin(+) population showed that the majority of the cells were also vimentin(+). Antibody-dependent complement mediated cytolysis of A2B5(+) (O2A cells) and galactocerebroside(+) (mature oligodendrocytes) cells left a population of nestin(+) cells that were induced to proliferate in the presence of growth factors and to differentiate into A2B5(+) and galactocerebroside(+) cells. Proliferating cells maintained in the presence of platelet-derived growth factor or basic fibroblast growth factor retained nestin expression along with A2B5. By contrast, in serum-free medium nestin expression decreased while postmitotic cells acquired A007 and galactocerebroside. Our results suggest that nestin expression is a marker of pre-O2A cells that is maintained in proliferating glial progenitors, but is quickly down-regulated in postmitotic oligodendrocytes (A007(+)/galacto-cerebroside(+)) along with A2B5 and vimentin. However, other glial cells including type 2 astrocytes and some amoeboid microglia also share nestin expression.     

New insights into the cellular makeup and progenitor potential of palatal connective tissues

The present study investigated the regenerative potential of connective tissues harvested from two palatal areas widely used as donor sites for muco‐gingival surgical approaches. Connective tissue grafts (CTGs) were obtained by de‐epithelialisation of a free gingival graft (deCTG) and by a split flap approach from a previous donor site (reCTG). Two types of mesenchymal stem cell (MSCs) were isolated and were named de‐epithelialised MSCs (deMSCs) and re‐entry MSCs (reMSCs). The cells were characterised and cellular functionality was investigated. CTGs were evaluated using immunohistochemical and ultrastructural approaches. No significant differences were observed regarding the frequency of colony‐forming unit‐ fibroblasts, migration potential, and population doubling time between the two cell lines (p > 0.05). Both cell lines showed positivity for CD105, CD73, CD90, and CD44 and negative expression for CD34/45, CD14, CD79a, and HLA‐DR. MSCs from both cell lines successfully differentiated into osteogenic, adipogenic, and chondrogenic lineages. Cells expressing antigens characteristic of CD34+ stromal cells (CD34+, αSMA?, CD31?) were traced in both CTGs. Ultrastructural analysis highlighted the presence of putative progenitors, namely fibroblasts,—in the pericapillary regions and in remote regions of the lamina propria‐ and pericytes—surrounding the capillaries. This study provides supplementary arguments for the use of CTG grafts in clinical practice due to the presence of putative progenitor cell. However, results were inconclusive regarding clinical decision‐making to determine optimal harvesting area. Prior harvesting in the donor area did not appear to alter the regenerative capabilities of the connective tissue.     

MSCs-exosomes in regeneration medicine: Current evidence and future perspectives

Exosomes, especially from mesenchymal stem cells, have attracted extensive attention in regeneration medicine. Mesenchymal stem cells derived exosomes (MSCs-exosomes) have shown anti-inflammatory, anti-oxidant, anti-apoptosis and tissue regeneration effects in a variety of tissue injury repair models. MSCs-exosomes hold many excellent properties such as low immunogenicity, biocompatibility, and targeting capability. With the in-depth study on the generation and function of exosomes, MSCs-exosomes are considered to be the bright stars in the field of regenerative medicine. However, there are still many obstacles to overcome in terms of exosomes isolation, clinical trials and safety evaluation. In this article, what we should focus on about MSCs-exosomes in regeneration medicine will be discussed.     

Microscopy analysis of bone marrow-derived osteoprogenitor cells cultured on hydrogel 3-D scaffold

Bone marrow contains progenitor cells that are able to differentiate into several mesenchymal lineages, including bone. These cells may also provide a potential therapy for bone repair. The purpose of this study was to select the osteoprogenitor cell subpopulation from bone marrow-derived mesenchymal stem cells (MSCs) and to test the ability of a hydrogel scaffold to support growth and osteogenic differentiation. MSCs isolated from rat femur bone marrow were cultured in DMEM medium supplemented with antibiotics, FCS, and L-glutamine. Osteogenic supplements (dexamethasone, sodium beta-glycerophosphate, and ascorbic acid) were added for one, two or three weeks. A selective subpopulation of osteoprogenitor cells was identified by immunohistochemistry, general morphology, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Committed osteogenic cells were transferred to a 3-D hydrogel scaffold and cultured for an additional week. In standard culture, the osteoprogenitor cells formed cell clusters identified by Alizarin red S staining and by positive osteocalcin immunostaining. The number of osteoprogenitor cells, matrix synthesis, and mineralization increased gradually up to three weeks in culture. Mineral deposition in the matrix analyzed by EDS revealed the presence of calcium and phosphate ions at a Ca/P molar ratio of 1.73 in both the osteogenic cultures and the scaffold osteoprogenitor culture. Histological preparations revealed cell clusters within the hydrogel scaffold and SEM analysis revealed cell clusters attached to the scaffold surface. It is concluded that the hydrogel scaffold can support growth and differentiation of osteogenic cultures including mineralization and can potentially serve as a bone graft substitute containing committed osteoprogenitor cells.     

Adipose-derived mesenchymal stem/stromal cells: from the lab bench to the basic concepts for clinical translation

In the last years, much work has shown that the most effective repair system of the body is represented by stem cells, which are defined as undifferentiated precursors that own unlimited or prolonged self-renewal ability, which also have the potential to transform themselves into various cell types through differentiation.All tissues that form the body contain many different types of somatic cells, along with stem cells that are called ‘mesenchymal stem (or stromal) cells’ (MSC). In certain circumstances, some of these MSC migrate to injured tissues to replace dead cells or to undergo differentiation to repair it.The discovery of MSC has been an important step in regenerative medicine because of their high versatility. Moreover, the finding of a method to isolate MSC from adipose tissue, so called ‘adipose-derived mesenchymal stem cells’ (ASC), which share similar differentiation capabilities and isolation yield that is greater than other MSC, and less bioethical concerns compared to embryonic stem cells, have created self-praised publicity to procure almost any treatment with them. Here, we review the current techniques for isolation, culture and differentiation of human ASC (hASC), and describe them in detail. We also compile some advantages of the hASC over other stem cells, and provide some concepts that could help finding strategies to promote their therapeutic efficiency.