Clonal multilineage differentiation of murine common pluripotent stem cells isolated from skeletal muscle and adipose stromal cells

Mouse Neural Stem Cell Differentiation and Human Adipose Mesenchymal Stem Cell Transdifferentiation Into Neuron- and Oligodendrocyte-like Cells With Myelination Potential

Stem cell therapy is an interesting approach for neural repair, once it can improve and increase processes, like angiogenesis, neurogenesis, and synaptic plasticity. In this regard, adult neural stem cells (NSC) are studied for their mechanisms of proliferation, differentiation and functionality in neural repair. Here, we describe novel neural differentiation methods. NSC from adult mouse brains and human adipose-derived stem cells (hADSC) were isolated and characterized regarding their neural differentiation potential based on neural marker expression profiles. For both cell types, their capabilities of differentiating into neuron-, astrocyte- and oligodendrocytes-like cells (NLC, ALC and OLC, respectively) were analyzed. Our methodologies were capable of producing NLC, ALC and OLC from adult murine and human transdifferentiated NSC. NSC showed augmented gene expression of NES, TUJ1, GFAP and PDGFRA/Cnp. Following differentiation induction into NLC, OLC or ALC, specific neural phenotypes were obtained expressing MAP2, GalC/O4 or GFAP with compatible morphologies, respectively. Accordingly, immunostaining for nestin⁺ in NSC, GFAP⁺ in astrocytes and GalC/O4⁺ in oligodendrocytes was detected. Co-cultured NLC and OLC showed excitability in 81.3% of cells and 23.5% of neuron/oligodendrocyte marker expression overlap indicating occurrence of in vitro myelination. We show here that hADSC can be transdifferentiated into NSC and distinct neural phenotypes with the occurrence of neuron myelination in vitro, providing novel strategies for CNS regeneration therapy. Superior Part: Schematic organization of obtaining and generating hNSC from hADSC and differentiation processes and phenotypic expression of neuron, astrocyte and oligodendrocyte markers (MAP2, GFAP and O4, respectively) and stem cell marker (NES) of differentiating hNSC 14 days after induction. The nuclear staining in blue corresponds to DAPI. bar = 100 μm. Inferior part: Neural phenotype fates in diverse differentiation media. NES: nestin; GFAP: Glial fibrillary acidic protein. MAP2: Microtubule-associated protein 2. TUJ1: β-III tubulin. PDGFRA: PDGF receptor alpha. Two-way ANOVA with Bonferroni post-test with n = 3. * p < 0.05 and ** p < 0.01: (NSCiM1 NSC induction medium 1) vs differentiation media.

IL-4 and SDF-1 Increase Adipose Tissue-Derived Stromal Cell Ability to Improve Rat Skeletal Muscle Regeneration

Skeletal muscle regeneration depends on the satellite cells, which, in response to injury, activate, proliferate, and reconstruct damaged tissue. However, under certain conditions, such as large injuries or myopathies, these cells might not sufficiently support repair. Thus, other cell populations, among them adipose tissue-derived stromal cells (ADSCs), are tested as a tool to improve regeneration. Importantly, the pro-regenerative action of such cells could be improved by various factors. In the current study, we tested whether IL-4 and SDF-1 could improve the ability of ADSCs to support the regeneration of rat skeletal muscles. We compared their effect at properly regenerating fast-twitch EDL and poorly regenerating slow-twitch soleus. To this end, ADSCs subjected to IL-4 and SDF-1 were analyzed in vitro and also in vivo after their transplantation into injured muscles. We tested their proliferation rate, migration, expression of stem cell markers and myogenic factors, their ability to fuse with myoblasts, as well as their impact on the mass, structure and function of regenerating muscles. As a result, we showed that cytokine-pretreated ADSCs had a beneficial effect in the regeneration process. Their presence resulted in improved muscle structure and function, as well as decreased fibrosis development and a modulated immune response.

The use of autologous fat grafts in breast surgery: A literature review

Autologous fat injection was first described roughly a century ago and has been used in surgery ever since. In addition to its use in many surgical fields, it is also frequently used for both aesthetic and reconstructive purposes in breast surgery. Since the application of fat grafting in breast surgery has steadily increased, studies investigating its reliability have simultaneously become increasingly common. Previous studies have reported that the use of fat grafting in breast surgery is reliable, but some pending questions remain about its routine use. In order to use fat grafts successfully in breast surgery, it is necessary to be familiar with the structure and content of adipose tissue, the efficacy of adipose stem cell-enriched fat grafts, the oncological safety of fat grafts, and the problems that may occur in the radiological follow-up of patients who undergo fat grafting procedures. In this literature review, we aim to discuss the use of fat grafts in breast surgery by investigating these common problems.

Injection Laryngoplasty Using Autologous Fat Enriched with Adipose-Derived Regenerative Stem Cells: A Safe Therapeutic Option for the Functional Reconstruction of the Glottal Gap after Unilateral Vocal Fold Paralysis

Background

Paralysis of one vocal fold leads to glottal gap and vocal fold insufficiency that has significant impact upon a patient's quality of life. Fillers have been tested to perform intracordal injections, but they do not provide perdurable results. Early data suggest that enriching fat grafts with adipose-derived regenerative cells (ADRCs) promote angiogenesis and modulate the immune response, improving graft survival. The aim of this study is to propose ADRC-enriched adipose tissue grafts as effective filler for the paralyzed vocal fold to use it for functional reconstruction of the glottal gap.

Method

This is the first phase I-IIA clinical trial (phase I/IIA clinical trial, unicentric, randomized, controlled, and two parallel groups), to evaluate the safety of a new therapy with ADRC-enriched fat grafting (ADRC: group I) for laryngoplasty after unilateral vocal fold paralysis. Control group patients received centrifuged autologous fat (CAF: group II) grafts. Overall mean age is 52.49 ± 16.60 years. Group I (ADRC): 7 patients (3 males and 4 females), 52.28 ± 20.95 year. Group II (CAF): 7 patients (3 males and 4 females), 52.71 ± 12.59 year.

Results

VHI-10 test showed that preoperative mean score was 24.21 ± 8.28. Postoperative mean score was 6.71 ± 6.75. Preoperative result in group I was 21.14 ± 3.58 and postoperative result was 3.14 ± 3.53. Preoperative result for group II was 27.29 ± 10.66. Postoperative score in group II was 10.29 ± 7.52. Wilcoxon and the Student t-tests showed that the patient's self-perception of posttreatment improvement is larger when ADRCs are used. Comparing pre- and posttreatment voice quality analysis, group I showed a p = 0.053. Group II showed a p = 0.007. There would be no significant differentiation between pre- and posttreatment results. This is true for group II and limited for group I.

Conclusions

This prospective trial demonstrates the safety and efficacy of the treatment of glottal gap defects utilizing ADRC-enriched fat grafts. This trial is registered with NCT02904824.

Synergy Between Choroid Plexus Epithelial Cell-Conditioned Medium and Knockout Serum Replacement Converts Human Adipose-Derived Stem Cells to Dopamine-Secreting Neurons

Human adipose-derived stem cells (hADSCs) have great capacity to differentiate into mesodermal origins as well as nonmesodermal lineages, including neural cells. This valuable feature paves the way for the therapeutic application of hADSCs for neurodegenerative maladies such as Parkinson's disease (PD). We tested the capacity of choroid plexus epithelial cell-conditioned medium (CPEC-CM) alone or cocktailed with knockout serum (KS) to induce dopaminergic (DAergic) differentiation of hADSCs. To this end, hADSCs from lipoaspirate were phenotypically characterized and shown to maintain mesodermal multipotency so that selected media easily differentiated them into osteoblasts, chondrocytes, and adipocytes. To begin inducing hADSC neuronal differentiation, we isolated CPECs from rat brain and expanded them in culture to obtain CPEC-CM. We then treated hADSCs with optimized quantities of collected CPEC-CM, KS, or both. The ADSCs treated with either CPEC-CM or CPEC-CM and KS displayed morphological changes typical of neuron-like phenotypes. As revealed by reverse transcription polymerase chain reaction (RT-PCR), quantitative real-time PCR (qPCR), and immunostaining analyses, hADSCs cotreated with CPEC-CM and KS expressed significantly higher levels of neuronal and DAergic markers in comparison with single-treated groups. Moreover, the hADSCs began expressing dopamine-biosynthesizing enzymes mainly after cotreatment with CPEC-CM and KS. Consequently, only cotreated hADSCs were capable of synthesizing and releasing dopamine detectable by high-performance liquid chromatography (HPLC). Finally, hADSCs growing in an ordinary medium were found positive for astrocytic marker glial fibrillary acidic protein (GFAP), but stopped GFAP expression on either single or cotreatments. These combined results suggest that CPEC-CM and KS can synergize to remarkably augment DAergic induction of hADSCs, an effect that has implications for cell replacement therapy for PD and related disorders.

Multimodal evaluation of ultra-short laser pulses treatment for skin burn injuries

Thousands of people die every year from burn injuries. The aim of this study is to evaluate the feasibility of high intensity femtosecond lasers as an auxiliary treatment of skin burns. We used an in vivo animal model and monitored the healing process using 4 different imaging modalities: histology, Optical Coherence Tomography (OCT), Second Harmonic Generation (SHG), and Fourier Transform Infrared (FTIR) spectroscopy. 3 dorsal areas of 20 anesthetized Wistar rats were burned by water vapor exposure and subsequently treated either by classical surgical debridement, by laser ablation, or left without treatment. Skin burn tissues were non-invasively characterized by OCT images and biopsied for further histopathology analysis, SHG imaging and FTIR spectroscopy at 3, 5, 7 and 14 days after burn. The laser protocol was found as efficient as the classical treatment for promoting the healing process. The study concludes to the validation of femtosecond ultra-short pulses laser treatment for skinburns, with the advantage of minimizing operatory trauma.

Neuronal differentiation of adipose-derived stem cells and their transplantation for cerebral ischemia

OBJECTIVE

To review published data on the biological characteristics, differentiation and applications of adipose-derived stem cells in ischemic diseases.

DATA RETRIEVAL

A computer-based online search of reports published from January 2005 to June 2012 related to the development of adipose-derived stem cells and their transplantation for treatment of cerebral ischemia was performed in Web of Science using the key words "adipose-derived stem cells", "neural-like cells", "transplantation", "stroke", and "cerebral ischemia".

SELECTION CRITERIA

The documents associated with the development of adipose-derived stem cells and their transplantation for treatment of cerebral ischemia were selected, and those published in the last 3-5 years or in authoritative journals were preferred in the same field. Totally 89 articles were obtained in the initial retrieval, of which 53 were chosen based on the inclusion criteria.

MAIN OUTCOME MEASURES

Biological characteristics and induced differentiation of adipose-derived stem cells and cell transplantation for disease treatment as well as the underlying mechanism of clinical application.

RESULTS

The advantages of adipose-derived stem cells include their ease of procurement, wide availability, rapid expansion, low tumorigenesis, low immunogenicity, and absence of ethical constraints. Preclinical experiments have demonstrated that transplanted adipose-derived stem cells can improve neurological functions, reduce small regions of cerebral infarction, promote angiogenesis, and express neuron-specific markers. The improvement of neurological functions was demonstrated in experiments using different methods and time courses of adipose-derived stem cell transplantation, but the mechanisms remain unclear.

CONCLUSION

Further research into the treatment of ischemic disease by adipose-derived stem cell transplantation is needed to determine their mechanism of action.

Differentiation of human adipose-derived stem cells into neuron-like cells which are compatible with photocurable three-dimensional scaffolds

Multipotent human adipose-derived stromal/stem cells (hADSCs) hold a great promise for cell-based therapy for many devastating human diseases, such as spinal cord injury and stroke. If exogenous hADSCs can be cultured in a three-dimensional (3D) scaffold with effective proliferation and differentiation capacity, it will better mimic the in vivo environment, which will have profound impact on the therapeutic application of hADSCs. In this study, a group of elastic-dominant, porous bioscaffolds from photocurable chitosan and gelatin were fabricated and proven to be biocompatible with both hADSCs and hADSC-derived neuron-like cells (hADSC-NLCs) in vitro. The identity of harvested hADSCs was confirmed by their positive immunostaining of mesenchymal stem cell surface markers, CD29, CD44, and CD105, and also positive expression of stem markers, Sox-2, Oct-4, c-Myc, Nanog, and Klf4. Their multipotency was further confirmed by trilineage differentiation of hADSCs toward adipocyte, osteoblast, and chondrocyte. It was found that hADSCs could be conditioned to differentiate into neurons in vitro as determined by immunostaining the markers of Tuj1, MAP2, NeuN, and Synapsin. The hADSCs and hADSC-NLCs were proven to be biocompatible with 3D scaffold, which actually facilitated the proliferation and differentiation of hADSCs in vitro, by MTT assay and their neuronal gene expression profiling. Moreover, hADSC-NLCs, which were mixed with 3D scaffold and transplanted into traumatic brain injury mouse model, survived in vivo and led to the better repair of the damaged brain area. The immunohistochemical studies revealed that 3D scaffold indeed improved the viability of transplanted cells, their ability to incorporate into the in vivo neural circuit, and their capacity for tissue repair. This study indicates that hADSCs would have great therapeutic application potential as seeding cells for in vivo transplantation to treat various neurological diseases when co-applied with porous chitosan/gelatin bioscaffolds.

Mesenchymal stem cells: new players in retinopathy therapy

Retinopathies in human and animal models have shown to occur through loss of pericytes resulting in edema formation, excessive immature retinal angiogenesis, and neuronal apoptosis eventually leading to blindness. In recent years, the concept of regenerating terminally differentiated organs with a cell-based therapy has evolved. The cells used in these approaches are diverse and include tissue-specific endogenous stem cells, endothelial progenitor (EPC), embryonic stem cells, induced pluripotent stem cells (iPSC) and mesenchymal stem cells (MSC). Recently, MSC derived from the stromal fraction of adipose tissue have been shown to possess pluripotent differentiation potential in vitro. These adipose stromal cells (ASC) have been differentiated in a number of laboratories to osteogenic, myogenic, vascular, and adipocytic cell phenotypes. In vivo, ASC have been shown to have functional and phenotypic overlap with pericytes lining microvessels in adipose tissues. Furthermore, these cells either in paracrine mode or physical proximity with endothelial cells, promoted angiogenesis, improved ischemia-reperfusion, protected from myocardial infarction, and were neuroprotective. Owing to the easy isolation procedure and abundant supply, fat-derived ASC are a more preferred source of autologous mesenchymal cells compared to bone marrow MSC. In this review, we present evidence that these readily available ASC from minimally invasive liposuction will facilitate translation of ASC research into patients with retinal diseases in the near future.

Valproic acid, a histone deacetylase inhibitor, decreases proliferation of and induces specific neurogenic differentiation of canine adipose tissue-derived stem cells

Adipose tissue-derived stem cells (ADSCs) isolated from adult tissue have pluripotent differentiation and self-renewal capability. The tissue source of ADSCs can be obtained in large quantities and with low risks, thus highlighting the advantages of ADSCs in clinical applications. Valproic acid (VPA) is a widely used antiepileptic drug, which has recently been reported to affect ADSC differentiation in mice and rats; however, few studies have been performed on dogs. We aimed to examine the in vitro effect of VPA on canine ADSCs. Three days of pretreatment with VPA decreased the proliferation of ADSCs in a dose-dependent manner; VPA concentrations of 4 mM and above inhibited the proliferation of ADSCs. In parallel, VPA increased p16 and p21 mRNA expression, suggesting that VPA attenuated the proliferative activity of ADSCs by activating p16 and p21. Furthermore, the effects of VPA on adipogenic, osteogenic or neurogenic differentiation were investigated morphologically. VPA pretreatment markedly promoted neurogenic differentiation, but suppressed the accumulation of lipid droplets and calcium depositions. These modifications of ADSCs by VPA were associated with a particular gene expression profile, viz., an increase in neuronal markers, that is, NSE, TUBB3 and MAP2, a decrease in the adipogenic marker, LPL, but no changes in osteogenic markers, as estimated by reverse transcription-PCR analysis. These results suggested that VPA is a specific inducer of neurogenic differentiation of canine ADSCs and is a useful tool for studying the interaction between chromatin structure and cell fate determination.

A simple method to generate adipose stem cell-derived neurons for screening purposes

Strategies involved in mesenchymal stem cell (MSC) differentiation toward neuronal cells for screening purposes are characterized by quality and quantity issues. Differentiated cells are often scarce with respect to starting undifferentiated population, and the differentiation process is usually quite long, with high risk of contamination and low yield efficiency. Here, we describe a novel simple method to induce direct differentiation of MSCs into neuronal cells, without neurosphere formation. Differentiated cells are characterized by clear morphological changes, expression of neuronal specific markers, showing functional response to depolarizing stimuli and electrophysiological properties similar to those of developing neurons. The method described here represents a valuable tool for future strategies aimed at personalized screening of therapeutic agents in vitro.

Nuclear fusion-independent smooth muscle differentiation of human adipose-derived stem cells induced by a smooth muscle environment

Human adipose-derived stem cells hASC have been isolated and were shown to have multilineage differentiation capacity. Although both plasticity and cell fusion have been suggested as mechanisms for cell differentiation in vivo, the effect of the local in vivo environment on the differentiation of adipose-derived stem cells has not been evaluated. We previously reported the in vitro capacity of smooth muscle differentiation of these cells. In this study, we evaluate the effect of an in vivo smooth muscle environment in the differentiation of hASC. We studied this by two experimental designs: (a) in vivo evaluation of smooth muscle differentiation of hASC injected into a smooth muscle environment and (b) in vitro evaluation of smooth muscle differentiation capacity of hASC exposed to bladder smooth muscle cells. Our results indicate a time-dependent differentiation of hASC into mature smooth muscle cells when these cells are injected into the smooth musculature of the urinary bladder. Similar findings were seen when the cells were cocultured in vitro with primary bladder smooth muscle cells. Chromosomal analysis demonstrated that microenvironment cues rather than nuclear fusion are responsible for this differentiation. We conclude that cell plasticity is present in hASCs, and their differentiation is accomplished in the absence of nuclear fusion.

Adipose-derived mesenchymal stromal/stem cells: tissue localization, characterization, and heterogeneity

Adipose tissue as a stem cell source is ubiquitously available and has several advantages compared to other sources. It is easily accessible in large quantities with minimal invasive harvesting procedure, and isolation of adipose-derived mesenchymal stromal/stem cells (ASCs) yields a high amount of stem cells, which is essential for stem-cell-based therapies and tissue engineering. Several studies have provided evidence that ASCs in situ reside in a perivascular niche, whereas the exact localization of ASCs in native adipose tissue is still under debate. ASCs are isolated by their capacity to adhere to plastic. Nevertheless, recent isolation and culture techniques lack standardization. Cultured cells are characterized by their expression of characteristic markers and their capacity to differentiate into cells from meso-, ecto-, and entodermal lineages. ASCs possess a high plasticity and differentiate into various cell types, including adipocytes, osteoblasts, chondrocytes, myocytes, hepatocytes, neural cells, and endothelial and epithelial cells. Nevertheless, recent studies suggest that ASCs are a heterogeneous mixture of cells containing subpopulations of stem and more committed progenitor cells. This paper summarizes and discusses the current knowledge of the tissue localization of ASCs in situ, their characterization and heterogeneity in vitro, and the lack of standardization in isolation and culture methods.

Stability of neural differentiation in human adipose derived stem cells by two induction protocols

There are some evidences for suggesting that adipose derived stem cells (ADSCs) can be differentiated to the fate of neural cell type. ADSCs can be expanded rapidly in vitro and can be obtained by a less invasive method. In this study, we attempted to compare the stability of neural differentiation in human ADSCs by using two induction protocols. Isolated ADSCs were induced into neural-like cells using diverse effects of two specific procedures. For protocol 1, ADSCs were induced by chemical induction. In protocol 2, ADSCs were treated for sphere formation. Then, the singled cells were cultured in neurobasal media supplemented with special components. Differentiated ADSCs were evaluated for Nestin, MAP2 and GFAP expression by immunocytochemistry and semi quantitative RT-PCR techniques. Moreover, MTT assay was employed to detect cell viability and proliferation. Immunocytochemical analysis of both protocols demonstrated that ADSCs had large expression of the neural-specific markers. In RT-PCR, protocol 1 showed the highest percentage of MAP2 expression, but with time passing, the neural like state was reversible. Protocol 2 found with express of Nestin at week 1, however MAP2 and GFAP expression increased after 3 weeks. The neural-like cells produced by protocol 1 led to the further cell death. Comparative analysis showed that neural-like cell differentiation of ADSCs in chemical induction protocol was rapid but transitory, while it was approximately steady in neurosphere formation protocol.

Functional neural differentiation of human adipose tissue-derived stem cells using bFGF and forskolin

Background

Adult mesenchymal stem cells (MSCs) derived from adipose tissue have the capacity to differentiate into mesenchymal as well as endodermal and ectodermal cell lineage in vitro. We characterized the multipotent ability of human adipose tissue-derived stem cells (hADSCs) as MSCs and investigated the neural differentiation potential of these cells.

Results

Human ADSCs from earlobe fat maintained self-renewing capacity and differentiated into adipocytes, osteoblasts, or chondrocytes under specific culture conditions. Following neural induction with bFGF and forskolin, hADSCs were differentiated into various types of neural cells including neurons and glia in vitro. In neural differentiated-hADSCs (NI-hADSCs), the immunoreactivities for neural stem cell marker (nestin), neuronal markers (Tuj1, MAP2, NFL, NFM, NFH, NSE, and NeuN), astrocyte marker (GFAP), and oligodendrocyte marker (CNPase) were significantly increased than in the primary hADSCs. RT-PCR analysis demonstrated that the mRNA levels encoding for ABCG2, nestin, Tuj1, MAP2, NFL, NFM, NSE, GAP43, SNAP25, GFAP, and CNPase were also highly increased in NI-hADSCs. Moreover, NI-hADSCs acquired neuron-like functions characterized by the display of voltage-dependent tetrodotoxin (TTX)-sensitive sodium currents, outward potassium currents, and prominent negative resting membrane potentials under whole-cell patch clamp recordings. Further examination by RT-PCR showed that NI-hADSCs expressed high level of ionic channel genes for sodium (SCN5A), potassium (MaxiK, Kv4.2, and EAG2), and calcium channels (CACNA1C and CACNA1G), which were expressed constitutively in the primary hADSCs. In addition, we demonstrated that Kv4.3 and Eag1, potassium channel genes, and NE-Na, a TTX-sensitive sodium channel gene, were highly induced following neural differentiation.

Conclusions

These combined results indicate that hADSCs have the same self-renewing capacity and multipotency as stem cells, and can be differentiated into functional neurons using bFGF and forskolin.

Adipocytes as immune cells: differential expression of TWEAK, BAFF, and APRIL and their receptors (Fn14, BAFF-R, TACI, and BCMA) at different stages of normal and pathological adipose tissue development

Adipose tissue represents a rich source of multipotent stem cells. Mesenchymal cells, isolated from this source, can differentiate to other cell types in vitro and therefore can be used for a number of regenerative therapies. Our view of adipose tissue has recently changed, establishing adipocytes as new members of the immune system, as they produce a number of proinflammatory cytokines (such as IL-6 and TNFalpha and chemokines, in addition to adipokines (leptin, adiponectin, resistin) and molecules associated with the innate immune system. In this paper, we report the differential expression of TNF-superfamily members B cell activating factor of the TNF Family (BAFF), a proliferation inducing ligand (APRIL), and TNF-like weak inducer of apoptosis (TWEAK) in immature-appearing and mature adipocytes and in benign and malignant adipose tissue-derived tumors. These ligands act through their cognitive receptors, BAFF receptor, transmembrane activator and calcium signal-modulating cyclophilic ligand (TACI), B cell maturation Ag (BCMA), and fibroblast growth factor-inducible 14 (Fn14), which are also expressed in these cells. We further report the existence of functional BCMA, TACI, and Fn14 receptors and their ligands BAFF, APRIL, and TWEAK on adipose tissue-derived mesenchymal cells, their interaction modifying the rate of adipogenesis. Our data integrate BAFF, APRIL, and TWEAK and their receptors BCMA, TACI, and Fn14 as novel potential mediators of adipogenesis, in addition to their specific role in immunity, and define immature and mature adipocytes as source of immune mediators.

The effect of type I collagen on osteochondrogenic differentiation in adipose-derived stromal cells in vivo

BACKGROUND

Recent studies have demonstrated that adipose-derived adult stromal cells (ADASCs) offer great promise for cell-based therapies due to their ability to differentiate towards bone, cartilage and fat [corrected] The objective of this study was to investigate whether type I collagen would elicit in vivo bone formation of passaged rat adipose-derived adult stromal cells (ADASC) placed extraskeletally.

METHODS

After expansion for 1-4 passages (P), cells were incubated in osteogenic medium containing dexamethasone, ascorbic acid and beta-glycerol phosphate for 2-4 weeks. Undifferentiated cells were maintained in Dulbecco's modified Eagle's medium (DMEM) with 10% fetal bovine serum (FBS). Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) and von Kossa staining as well as by gene expression of ALP, osteopontin (OP), osteonectin (ON), osteocalcin (OC), collagen I (colI), collagen II (colII), bone sialoprotein (BSP), periostin (Postn), runx2, osterix (Osx), sox9, msx1 and msx2. Diffusion chambers were filled with 1x10(6) cells mixed with or without type I collagen gel and implanted subcutaneously into rats. Controls included chambers exposed to (1) undifferentiated cells (with or without collagen, (2) collagen without cells and (3) empty chambers (n=5 per group).

RESULTS

Four weeks after implantation, in vivo bone and cartilage formation was demonstrated in implants containing 4-week osteo-induced P1 and P4 cells wrapped in the collagen gel, as confirmed by Goldner's trichrome and Alcian blue staining, respectively. Newly formed bone stained positive for type I collagen. Control implants had no bone or cartilage and were primarily filled with fibrous tissue at that time interval.

DISCUSSION

Recent studies have demonstrated that ADASC offer great promise for cell-based therapies because of their ability to differentiate toward bone, cartilage and fat. However, the influence of different matrices on the in vivo osteogenic capability of ADASC is not fully understood. These findings suggest that type I collagen may support the survival and expression of osteogenic and chondrogenic phenotypes in passaged rat ADASC in vivo.

The scientific basis for lipotransfer: is it the ideal filler?

A loss of volume results from a reduction in the subcutaneous fat, muscle atrophy, and changes in skeletal framework. Such loss of tissue volume compounded with tissue laxity leads to the aged appearance of the periorbital, perioral, cheek, and mandibular areas. Many facial plastic surgeons have sought to replace this volume with various injectable agents, both synthetic and autologous, in search for the ideal soft tissue filler. This article reviews the literature on lipotransfer and specifically the scientific basis underlying the approach.

Myogenic stem cells

Both skeletal muscle and bone marrow tissue contain myogenic stem cells. The population residing in muscles is heterogenic. Predominant in number are "typical" satellite cells - muscle progenitors migrating from somites during embryonic life. Another population is group of multipotent muscle stem cells which, at least in part, are derived from bone marrow. These cells are tracked by gradient of growth factors releasing from muscle during injury or exercise. Recruited bone marrow-derived cells gradually change their phenotype becoming muscle stem cells and eventually can attain satellite cell position and express Pax7 protein. Mesenchymal stem cells (MSC) isolated directly from bone marrow also display myogenic potential, although methods of induction of myogenic differentiation in vitro have not been optimized yet. Concerning efforts of exploiting myogenic stem cells in cell-mediated therapies it is important to understand the cause of impaired regenerative potential of aged muscle. Up to now, most of research data suggest that majority of age related changes in skeletal muscles are reversible, thus depending on extrinsic factors. However, irreversible intrinsic features of muscle stem cells are also taken into consideration.

Differentiation of human adipose-derived adult stem cells into neuronal tissue: does it work?

Adipose tissue contains many cells and proteins that are of value not only for their potential therapeutic applications, but also for the low cost of their harvest and delivery. Mesenchymal stem cells (MSC) were originally isolated from the bone marrow, although similar populations have been isolated from adipose and other tissues. At one time, neural tissues were not regarded as regenerative populations of cells. Therefore, the identification of cell populations capable of neuronal differentiation has generated immense interest. Adipose tissue may represent an alternative source of cells that are capable of neuronal differentiation, potentially enhancing its use in the treatment of neurological disease. The aim of this review is to cover the current state of knowledge of the differentiation potential of human adipose-derived stem (ADAS) cells, specifically their ability to give rise to neuronal cells in vitro. This review presents and discusses different protocols used for inducing human ADAS cells to differentiate in vitro, and the neuronal markers utilized in each system.

A neural network model for cell classification based on single-cell biomechanical properties

The potential success of tissue engineering or other cell-based therapies is dependent on factors such as the purity and homogeneity of the source cell populations. The ability to enrich cell harvests for specific phenotypes can have significant effects on the overall success of such therapies. While most techniques for cell sorting or enrichment have relied on cell surface markers, recent studies have shown that single-cell mechanical properties can serve as identifying markers of phenotype. In this study, a neural network modeling approach was developed to classify mesenchymal-derived primary and stem cells based on their biomechanical properties. Cell sorting was simulated using previously published data characterizing the mechanical properties of several different cell types as measured by atomic force microscopy. Neural networks were trained using combined data sets, with the resultant groupings analyzed for their purity, efficiency, and enrichment. Heterogeneous populations of zonal chondrocytes, chondrosarcoma cells, and mesenchymal-lineage cells, respectively, could all be classified into enriched subpopulations. Additionally, adult stem cells (adipose-derived or bone marrow-derived) separated disproportionately into nodes associated with the three primary mesenchymal lineages examined. These findings suggest that mathematical approaches such as neural network modeling, in combination with novel measures of cell properties, may provide a means of classifying and eventually sorting mixed populations of cells that are otherwise difficult to identify using more established techniques. In this respect, the identification of biomechanically based cell properties that increase the percentage of stem cells capable of differentiating into predictable lineages may improve the overall success of cell-based therapies.

Adipose-derived stem cells

Human adipose tissue has been shown to contain a population of cells that possesses extensive proliferative capacity and the ability to differentiate into multiple cell lineages. These cells are referred to as adipose tissue-derived stem cells (ADSCs) and are generally similar, though not identical, to mesenchymal stem cells (also referred to as marrow stromal cells). ADSCs for research are most conveniently extracted from tissue removed during an elective cosmetic liposuction procedure but may also be obtained from resected adipose tissue. This chapter describes surgical procedures associated with improved ADSC recovery and the processes by which aspirated adipose tissue is washed and digested with collagenase to yield a heterogeneous population from which ADSCs can be expanded. The large volume of tissue obtained from a liposuction procedure (average approximately 2 L), combined with the relatively high frequency of ADSC within the digestate, yields substantially more stem cells than can be realized from marrow without extensive expansion in culture.

In vitro clonal analysis of murine pluripotent stem cells isolated from skeletal muscle and adipose stromal cells

OBJECTIVE

Possible clinical utility of pluripotent stem cells (PSCs) with multilineage differentiation capacity depends on their ability to adapt to tissue-specific differentiation conditions. Previous data from our laboratory suggest that putative PSCs exhibiting an immunophenotype of CD45(-)Sca-1+CD117(-)CD90+ can be isolated from multiple tissues. In the present study, the clonal in vitro differentiation potential of two isolates of PSCs was examined.

MATERIALS AND METHODS

Clonal analysis of the differentiation potential of skeletal muscle- (SM) and adipose stromal cell (ASC)-derived PSCs into myogenic, adipogenic, and neurogenic cells was investigated by expanding single PSCs prior to specification under three separate differentiation conditions.

RESULTS

Differentiation of SM- and ASC-derived PSCs into myotubes, adipocytes, and neuronal-like cells was evident in clonal cultures promoting differentiation along these lineages. A total of 2.0%, 1.0%, and 0.33% of SM-derived clones demonstrated unipotent, bipotent, and tripotent differentiation, respectively, into combinations of myocytes, adipocytes, and neuronal cells. As a percentage of SM-derived PSCs, tripotent clones comprised 0.016% of total muscle cells. Similar results were obtained with ASC-derived PSCs, suggesting phenotypic and functional similarities between PSCs from both tissues. Following differentiation of single PSCs into three lineages, a clear and complete commitment to tissue-specific gene expression accompanied by inactivation of lineage-unrelated genes could not be demonstrated in several SM- and ASC-derived clones.

CONCLUSIONS

These data demonstrate that phenotypically defined PSCs remain functionally heterogeneous at the single-cell level and illustrate that morphologic lineage commitment may be independent of exclusive expression and/or loss of associated lineage specific genes.

Insulin growth factor signaling mediates neuron-like differentiation of adipose-tissue-derived stem cells

Our previous study showed that adipose tissue-derived stem cells (ADSC) could be induced by isobutylmethylxanthine (IBMX) to differentiate into neuron-like cells. In the present study, ADSC were treated with IBMX in the presence or in the absence of each of eight specific inhibitors of different signaling pathways (JAK/STAT, PKA, PI3K, MEK, Wnt/Frizzled, ERK/MAPK, TGF-beta, and insulin growth factor [IGF]-I). PPP, a specific inhibitor of IGF-I signaling, was the only inhibitor that showed significant inhibition of IBMX-induced ADSC neuronal differentiation, as determined by changes in cell morphology in the initial screening. Further examination by immunofluorescence staining showed that the neuronal marker, beta-III-tubulin, was highly induced in IBMX-treated ADSC, and the induction was significantly suppressed by PPP. Western blotting, followed by densitometry showed that PPP suppressed IBMX-induced beta-III-tubulin expression by 43%, 88%, and 84% when used to treat the cells for 1, 3, and 24 hr, respectively. Treatment of ADSC with IBMX also led to the phosphorylation of IGF-I receptor at tyrosine 1136 (Y1136), as determined by immunofluorescence staining with an antibody that reacts specifically with Y1136. This effect was also abrogated by PPP. Thus, the IBMX-induced neuron-like differentiation of ADSC is mediated by IGF signaling through the phosphorylation of IGF-IR at Y1136.

A population of multipotent CD34-positive adipose stromal cells share pericyte and mesenchymal surface markers, reside in a periendothelial location, and stabilize endothelial networks

It has been shown that stromal-vascular fraction isolated from adipose tissues contains an abundance of CD34+ cells. Histological analysis of adipose tissue revealed that CD34+ cells are widely distributed among adipocytes and are predominantly associated with vascular structures. The majority of CD34+ cells from freshly isolated stromal-vascular fraction were CD31-/CD144- and could be separated from a distinct population of CD34+/CD31+/CD144+ (endothelial) cells by differential attachment on uncoated plastic. The localization of CD34+ cells within adipose tissue suggested that the nonendothelial population of these cells occupied a pericytic position. Analysis of surface and intracellular markers of the freshly isolated CD34+/CD31-/CD144- adipose-derived stromal cells (ASCs) showed that >90% coexpress mesenchymal (CD10, CD13, and CD90), pericytic (chondroitin sulfate proteoglycan, CD140a, and CD140b), and smooth muscle (alpha-actin, caldesmon, and calponin) markers. ASCs demonstrated polygonal self-assembly on Matrigel, as did human microvascular endothelial cells. Coculture of ASCs with human microvascular endothelial cells on Matrigel led to cooperative network assembly, with enhanced stability of endothelial networks and preferential localization of ASCs on the abluminal side of cords. Bidirectional paracrine interaction between these cells was supported by identification of angiogenic factors (vascular endothelial growth factor, hepatocyte growth factor, basic fibroblast growth factor), inflammatory factors (interleukin-6 and -8 and monocyte chemoattractant protein-1 and -2), and mobilization factors (macrophage colony-stimulating factor and granulocyte/macrophage colony-stimulating factor) in media conditioned by CD34+ ASCs, as well a robust mitogenic response of ASCs to basic fibroblast growth factor, epidermal growth factor, and platelet-derived growth factor-BB, factors produced by endothelial cells. These results demonstrate for the first time that the majority of adipose-derived adherent CD34+ cells are resident pericytes that play a role in vascular stabilization by mutual structural and functional interaction with endothelial cells.

Cre reconstitution allows for DNA recombination selectively in dual-marker-expressing cells in transgenic mice

Cre/LoxP-based DNA recombination has been used to introduce desired DNA rearrangements in various organisms, having for example, greatly assisted genetic analyses in mice. For most applications, single gene promoters are used to drive Cre production for conditional gene activation/inactivation or lineage-tracing experiments. Such a manipulation introduces Cre in all cells in which the utilized promoter is active. To overcome the limited selectivity of single promoters for cell-type-specific recombination, we have explored the ‘dual promoter combinatorial control’ of Cre activity, so that Cre activity could be restricted to cells that express dual protein markers. We efficiently reconstituted Cre activity from two modified, inactive Cre fragments. Cre re-association was greatly enhanced by fusing the Cre fragments separately to peptides that can form a tight antiparallel leucine zipper. The co-expressed Cre fusion fragments showed substantial activity in cultured cells. As proof of principle of the utility of this technique in vivo for manipulating genes specifically in dual-marker-positive cells, we expressed each inactive Cre fragments in transgenic mice via individual promoters. Result showed the effective reconstitution of Cre activates LoxP recombination in the co-expressing cells.

Biological character of human adipose-derived adult stem cells and influence of donor age on cell replication in culture

To investigate the biological character of human adipose-derived adult stem cells (hADAS cells) when cultured in vitro and the relationship between hADAS cell's replication activity and the donor's age factor, and to assess the stem cells as a new source for tissue engineering. hADAS cells are isolated from human adipose tissue of different age groups (from adolescents to olds: <20 years old, 21-40 years old, 41-60 years old and >61 years old groups). The protein markers (CD29, CD34, CD44, CD45, CD49d, HLA-DR, CD106) of hADAS cells were detected by flow cytometry (FCM) to identify the stem cell, and the cell cycle was examined for P20 hADAS cells to evaluate the safety of the subculture in vitro. The generative activity of hADAS cells in different age groups was also examined by MTT method. The formula "TD = t x log2/logNt - logN0" was used to get the time doubling (TD) of the cells. The results showed that the cells kept heredity stabilization by chromosome analysis for at least 20 passages. The TD of these cells increased progressively by ageing, and the TD of the <20 years old group was lower than that of the >61 years old group (statistical analysis of variance (ANOVA), P=0.002, P<0.05). These findings suggested that a higher level of hADAS cells replication activity was found in the younger donators, and they represent novel and valuable seed cells for studies of tissue engineering.

Adipose-derived stem cells for regenerative medicine

The emerging field of regenerative medicine will require a reliable source of stem cells in addition to biomaterial scaffolds and cytokine growth factors. Adipose tissue represents an abundant and accessible source of adult stem cells with the ability to differentiate along multiple lineage pathways. The isolation, characterization, and preclinical and clinical application of adipose-derived stem cells (ASCs) are reviewed in this article.

Neuron-like differentiation of adipose tissue-derived stromal cells and vascular smooth muscle cells

Adipose tissue-derived stromal cells (ADSC) have previously been shown to possess stem cell properties such as transdifferentiation and self-renewal. Because future clinical applications are likely to use these adult stem cells in an autologous fashion, we wished to establish and characterize rat ADSC for pre-clinical tests. In the present study, we showed that rat ADSC expressed stem cell markers CD34 and STRO-1 at passage 1 but only STRO-1 at passage 3. These cells could also be induced to differentiate into adipocytes, smooth muscle cells, and neuron-like cells, the latter of which expressed neuronal markers S100, nestin, and NF70. Isobutylmethylxanthine (IBMX), indomethacin (INDO), and insulin were the active ingredients in a previously established neural induction medium (NIM); however, here we showed that IBMX alone was as effective as NIM in the induction of morphological changes as well as neuronal marker expression. Finally, we showed that vascular smooth muscle cells could also be induced by either NIM or IBMX to differentiate into neuron-like cells that expressed NF70.

Transcriptome of the subcutaneous adipose tissue in response to oral supplementation of type 2 Leprdb obese diabetic mice with niacin-bound chromium

The effects of oral niacin-bound chromium (NBC) supplementation on the subcutaneous fat tissue of type 2 Lepr db obese diabetic mice were examined using high-density comprehensive mouse genome (45,101 probe sets) expression arrays. The influence of such supplementation on the plasma cardiovascular risk factors of these mice was also investigated. Supplementation of NBC had no significant effect on age-dependent weight gain in the Lepr db obese diabetic mice. However, NBC lowered total cholesterol (TC), TC-to-HDL ratio, LDL cholesterol, and triglyceride levels while increasing HDL cholesterol in the blood plasma. No effect of NBC supplementation was observed on fasting blood glucose levels. Oral glucose tolerance test revealed a significantly improved clearance of blood glucose between 1 and 2 h of glucose challenge in NBC-supplemented mice. Unbiased genome-wide interrogation demonstrated that NBC resulted in the upregulation of muscle-specific gene expression in the fat tissue. Genes encoding proteins involved in glycolysis, muscle contraction, muscle metabolism, and muscle development were specifically upregulated in response to NBC supplementation. Genes in the adipose tissue that were downregulated in response to NBC supplementation included cell death-inducing DNA fragmentation factor (CIDEA) and uncoupling protein-1, which represent key components involved in the thermogenic role of brown adipose tissue and tocopherol transfer protein, the primary carrier of α-tocopherol to adipose tissue. The observation that CIDEA-null mice are resistant to obesity and diabetes suggests that the inhibitory role of NBC on CIDEA expression was favorable. Further studies testing the molecular basis of NBC function and long-term outcomes are warranted.

Adipose-derived stem and progenitor cells as fillers in plastic and reconstructive surgery

Plastic surgeons are keenly aware of the principle "replace like with like." This principle underlies much of the rationale behind the clinical use of autologous fat transplantation, despite the procedure's drawbacks. Autologous fat transplantation is frequently used for a variety of cosmetic and reconstructive indications not limited to posttraumatic defects of the face and body, involutional disorders such as hemifacial atrophy, sequelae of radiation therapy, and many aesthetic uses such as lip and facial augmentation and wrinkle therapy. However, the limitations of fat transplantation are well known, particularly the long-term unpredictability of volume maintenance. Regenerative cell-based strategies such as those encompassing the use of stem cells hold tremendous promise for augmentation of the soft-tissue space. Preclinical studies and early clinical series show that adipose-derived stem cells offer the possibility of finally fulfilling the key principle of replacing like with like as an aesthetic filler, without the drawbacks of current technology.

Role of adipose tissue as an inflammatory organ in human diseases

Reviews on the inflammatory role of adipose tissue outside the field of metabolism are rare. There is increasing evidence provided by numerous basic research studies from nearly all internal medicine subspecializations that adipocytes and adipocytokines are involved in primary inflammatory processes and diseases. Therefore, it is the aim of the present review to discuss and to summarize the current knowledge on the inflammatory role of adipocytokines and special types of regional adipocytes such as retroorbital, synovial, visceral, subdermal, peritoneal, and bone marrow adipocytes in internal medicine diseases. Future clinical and therapeutic implications are discussed.

Skeletal muscle-derived progenitor cells exhibit neural competence

Skeletal muscle contains heterogenous progenitor cells that give rise to muscle, hematopoietic cells and bone. The exact phenotypic definition of skeletal muscle progenitor cells has not been fully elucidated nor the potential of these cells to differentiate into neurons. Here, we demonstrate that phenotypically homogenous skeletal muscle progenitor cells defined as Lin-CD45-CD117-CD90+ cells express neural stem cell markers and are responsive to neural induction signals. When exposed to neural induction medium containing basic fibroblast growth factor and brain-derived neurotrophic factor, skeletal muscle progenitor cells dramatically changed their cell morphology, became postmitotic and began expressing neuronal markers. These results reveal unexpected potentials of muscle progenitor cells and suggest that these cells may potentially be used in cell-based therapies to replace damaged neurons.