Translational products of adipose tissue-derived mesenchymal stem cells:Bench to bedside applications

With developments in the field of tissue engineering and regenerative medicine,the use of biological products for the treatment of various disorders has come into the limelight among researchers and clinicians.Among all the available biological tissues,research and exploration of adipose tissue have become more robust.Adipose tissue engineering aims to develop by-products and their substitutes for their regenerative and immunomodulatory potential.The use of biodegradable scaffolds along with adipose tissue products has a major role in cellular growth,proliferation,and differentiation.Adipose tissue,apart from being the powerhouse of energy storage,also functions as the largest endocrine organ,with the release of various adipokines.The progenitor cells among the heterogeneous population in the adipose tissue are of paramount importance as they determine the capacity of regeneration of these tissues.The results of adipose-derived stemcell assisted fat grafting to provide numerous growth factors and adipokines that improve vasculogenesis,fat graft integration,and survival within the recipient tissue and promote the regeneration of tissue are promising.Adipose tissue gives rise to various by-products upon processing.This article highlights the significance and the usage of various adipose tissue by-products,their individual characteristics,and their clinical applications.

Anti-osteoarthritis effect of a combination treatment with human adipose tissue-derived mesenchymal stem cells and thrombospondin 2 in rabbits

BACKGROUND Osteoarthritis(OA),a chronic age-related disease characterized by the slowly progressive destruction of articular cartilage,is one of the leading causes of disability.As a new strategy for treatment of OA,mesenchymal stem cells(MSCs)have the potential for articular cartilage regeneration.Meanwhile,thrombospondin 2(TSP2)promotes the chondrogenic differentiation of MSCs.AIM To investigate whether TSP2 induces chondrogenic differentiation of human adipose-derived MSCs(hADMSCs)and potentiates the therapeutic effects of hADMSCs in OA rabbits.METHODS We investigated the chondrogenic potential of TSP2 in hADMSCs by analyzing the expression of chondrogenic markers as well as NOTCH signaling genes in normal and TSP2 small interfering RNA(siRNA)-treated stem cells.Anterior cruciate ligament transection surgery was performed in male New Zealand white rabbits,and 8 wk later,hADMSCs(1.7×10^6 or 1.7×10^7 cells)were injected into the injured knees alone or in combination with intra-articular injection of TSP2(100 ng/knee)at 2-d intervals.OA progression was monitored by gross,radiological,and histological examinations.RESULTS In hADMSC culture,treatment with TSP2 increased the expression of chondrogenic markers(SOX9 and collagen Ⅱ)as well as NOTCH signaling genes(JAGGED1 and NOTCH3),which were inhibited by TSP2 siRNA treatment.In vivo,OA rabbits treated with hADMSCs or TSP2 alone exhibited lower degree of cartilage degeneration,osteophyte formation,and extracellular matrix loss 8 wk after cell transplantation.Notably,such cartilage damage was further alleviated by the combination of hADMSCs and TSP2.In addition,synovial inflammatory cytokines,especially tumor-necrosis factor-α,markedly decreased following the combination treatment.CONCLUSION The results indicate that TSP2 enhances chondrogenic differentiation of hADMSCs via JAGGED1/NOTCH3 signaling,and that combination therapy with hADMSCs and TSP2 exerts synergistic effects in the cartilage regeneration of OA joints.

Ameliorative effects of human adipose tissue-derived mesenchymal stem cells on myelin basic protein-induced experimental autoimmune encephalomyelitis in Lewis rats

Mesenchymal stem cells have been previously shown to exert an immunomodulatory function. The present study sought to investigate the effects of multipotential human adipose tissue-derived mesenchymal stem cells （hAdMSCs） on disease progression and cytokine expression in Lewis rats with experimental autoimmune encephalomyelitis （EAE） induced by myelin basic protein. The duration of EAE paralysis in the group treated on day 7 posfimmunization with 5 × 10^6 hAdMSCs was significantly reduced compared with the vehicle-treated controls and the 1 x 106 hAdMSC- treated group. The duration of EAE paralysis in the groups treated with 5 × 10^6 hAdMSCs on both day 1 and day 7 postimmunization was significantly reduced compared with the vehicle-treated controls and the groups treated with 5 × 10^6 hAdMSCs on both day 7 and day 10 postimmunization. The mRNA expression of interleukin-10 and indoleamine 2, 3-dioxygenase was significantly decreased in the hAdMSC-treated group compared with the vehicle-treated group. These findings suggest that the ameliorative effects of hAdMSCs on EAE symptoms operate in a dose- and time-dependent manner and can be mediated in part by the ample production of anti-inflammatory cytokines.

Outcomes of combined mitochondria and mesenchymal stem cellsderived exosome therapy in rat acute respiratory distress syndrome and sepsis

BACKGROUND The treatment of acute respiratory distress syndrome(ARDS)complicated by sepsis syndrome(SS)remains challenging.AIM To investigate whether combined adipose-derived mesenchymal-stem-cells(ADMSCs)-derived exosome(EXAD)and exogenous mitochondria(mitoEx)protect the lung from ARDS complicated by SS.METHODS In vitro study,including L2 cells treated with lipopolysaccharide(LPS)and in vivo study including male-adult-SD rats categorized into groups 1(sham-operated-control),2(ARDS-SS),3(ARDS-SS+EXAD),4(ARDS-SS+mitoEx),and 5(ARDS-SS+EXAD+mitoEx),were included in the present study.RESULTS In vitro study showed an abundance of mitoEx found in recipient-L2 cells,resulting in significantly higher mitochondrial-cytochrome-C,adenosine triphosphate and relative mitochondrial DNA levels(P<0.001).The protein levels of inflammation[interleukin(IL)-1β/tumor necrosis factor(TNF)-α/nuclear factor-κB/toll-like receptor(TLR)-4/matrix-metalloproteinase(MMP)-9/oxidative-stress(NOX-1/NOX-2)/apoptosis(cleaved-caspase3/cleaved-poly(ADP-ribose)polymerase)]were significantly attenuated in lipopolysaccharide(LPS)-treated L2 cells with EXAD treatment than without EXAD treatment,whereas the protein expressions of cellular junctions[occluding/β-catenin/zonula occludens(ZO)-1/E-cadherin]exhibited an opposite pattern of inflam-mation(all P<0.001).Animals were euthanized by 72 h post-48 h-ARDS induction,and lung tissues were harvested.By 72 h,flow cytometric analysis of bronchoalveolar lavage fluid demonstrated that the levels of inflam-matory cells(Ly6G+/CD14+/CD68+/CD11b/c+/myeloperoxidase+)and albumin were lowest in group 1,highest in group 2,and significantly higher in groups 3 and 4 than in group 5(all P<0.0001),whereas arterial oxygen-saturation(SaO2%)displayed an opposite pattern of albumin among the groups.Histopathological findings of lung injury/fibrosis area and inflammatory/DNA-damaged markers(CD68+/γ-H2AX)displayed an identical pattern of SaO2%among the groups(all P<0.0001).The protein expressions of inflammatory(TLR-4/MMP-9/IL-1β/TNF-α)/oxidative stress(NOX-1/NOX-2/p22phox/oxidized protein)/mitochondrial-damaged(cytosolic-cytochrome-C/dynamin-related protein 1)/autophagic(beclin-1/Atg-5/ratio of LC3B-II/LC3B-I)biomarkers exhibited a similar manner,whereas antioxidants[nuclear respiratory factor(Nrf)-1/Nrf-2]/cellular junctions(ZO-1/E-cadherin)/mitochondrial electron transport chain(complex I-V)exhibited an opposite manner of albumin among the groups(all P<0.0001).CONCLUSION Combined EXAD-mitoEx therapy was better than merely one for protecting the lung against ARDS-SS induced injury.

Therapeutic and regenerative potential of different sources of mesenchymal stem cells for cardiovascular diseases

Mesenchymalstemcells(MSCs)areidealcandidatesfortreatingmanycardiovasculardiseases.MSCscanmodify the internal cardiac microenvironment to facilitate their immunomodulatory and differentiation abilities,which are essential to restore heart function.MSCs can be easily isolated from different sources,including bone marrow,adipose tissues,umbilical cord,and dental pulp.MSCs from various sources differ in their regenerative and therapeutic abilities for cardiovascular disorders.In this review,we will summarize the therapeutic potential of each MSC source for heart diseases and highlight the possible molecular mechanisms of each source to restore cardiac function.

Differentiation of rat adipose tissue-derived mesenchymal stem cells towards a nucleus pulposus-like phenotype in vitro

Objective： To differentiate rat adipose tissue-derived mesenchymal stem cells （ADSCs） into cells with a nucleus pulposus-like phenotype in vitro, so as to lay a foundation for the cell-based transplantation therapy of degenerated intervertebral discs. Methods： Rat ADSCs were isolated only from the subcutaneous inguinal region and purified by limited dilution. ADSCs of the third passages were analyzed by fluorescence activated cell sorter （FACS） to detect the cell surface markers （Sca-1, CD44, CD45, CDI lb）. To induce ADSCs to- wards a nucleus pulposus-like phenotype, ADSCs were immobilized in 3-dimensional alginate hydrogels and cultured in an inducing medium containing transforming growth factor-beta1 （TGF- β1） under hypoxia （2% O2）, while control groups under normoxia （21% O2） in alginate beads in medium with or without the presence of TGF-β 1. Semiquantitative reverse transcription polymerase chain reaction （RT-PCR） was carried out to evaluate phenotypic and biosynthetic activities in the process of differentiation. Meanwhile, Alcian blue staining were used to detect the formation of sulfated glycosaminoglycans （GAGs） in the differentiated cells. Results： The purified ADSCs were fibroblast-like and proliferated rapidly in vitro. The flow cytometry showed that ADSCs were positive for Sca-1 and CD44, negative for CD45 and CD11b. The results of RT-PCR manifested that the gene expressions of Sox-9, aggrecan and collagen Ⅱ, which were chondrocyte specific, were upregulated in medium containing TGF-β1 under hypoxia （2% O2）. Likewise, gene expression of HIF-1 a, which was characteristics of in- tervertebral discs, was also upregulated. Simultaneously, Alcian blue staining exhibited the formation of many GAGs. Conclusions： The approach in our experiment is a simple and effective way to acquire a large quantity of homogenous ADSCs. Rat ADSCs can be differentiated into nucleus pulposus-like cells. ADSCs may replace bone marrow mesenchymal stem cells as a new kind of seed cells in regeneration of degenerated intervertebral discs using cell transolantation therarw.

Clinical and Magnetic Resonance Image Changes of Platelet-Rich Plasma Therapy in Combination with Human Mesenchymal Stem Cells from Autologous Adipose Tissue for Knee Osteoarthritis Treatment

Objective: To evaluate the efficacy based on clinical symptom and on magnetic resonance image of platelet-rich plasma therapy in combination with mesenchymal stem cells from autologous adipose tissue for knee osteoarthritis treatment. Patients and Method: 30 patients including 26 females and 4 males;correspondingly, 60 knee joints were diagnosed with osteoarthritis with stages II - III of Kellgren and Lawrence, their mean age was 58.63 ± 11.11. All were injected with autologous platelet-rich plasma that was extracted by PRP set, APC 30 PRP PRCEDURE PRAK and autologously extracted mesenchymal stem cells from abdominal adipose tissue using the ADI-25-01 ADIPOSEPRCEDURE PRAK of USA. Results: After 12 months: the pain level according to VAS score at the right knee joint was decreased from 6.0 ± 1.28 before treatment to 1.9 ± 0.3;VAS score at the left knee joint was decreased from 6.43 ± 1.19 to 2.25 ± 0.43. Total Lequene score at right knee joint was decreased from 16.04 ± 1.57 before treatment to 4.31 ± 1.04, at left knee joint was decreased from 17.52 ± 1.74 before treatment to 5.15 ± 1.48. Total WOMAC score at right knee joint was decreased from 55.93 ± 5.56 to 10.37 ± 1.56;at left knee joint was decreased from 53.97 ± 5.57 to 10.07 ± 1.59. There were 86.77% joints with cartilage thickness change and the patellar cartilage thickness was increased from 1.56 ± 0.09 mm before treatment to 1.65 ± 0.09 mm. Conclusion: The treatment of knee osteoarthritis by platelet-rich plasma therapyin combination with mesenchymal stem cells from autologous adipose tissue is effective in reducing pain, improving patient's mobility and walking function, reforming articular cartilage thickness on magnetic resonance image.

Adipose tissue-derived mesenchymal stem cells and chitosan/poly(vinyl alcohol)nanofibrous scaffolds for cartilage tissue engineering

Osteoarthritis(OA)has been defined as a chronic inflammatory joint disease characterized by progressive articular cartilage degeneration.Recently growing interest in regenerative medicine,using cell therapy and tissue engineering,where cellular components in combination with engineered scaffolds and bioactive materials were used to induce functional tissue regeneration.In the present study,nanofibrous scaffold based on chitosan(CS)/poly(vinyl alcohol)(PVA)were used to develop biologically functionalized biomaterial to mimic the extracellular matrix,allowing the human adipose tissue derived mesenchymal stem cells(ADSCs)to proliferate and differentiate to chondrogenic cells.The morphology of the nanofibrous mat was examined using field emission scanning electron microscope(FE/SEM).The characteristic functional groups and the nature of the chemical bonds between atoms were evaluated using Fourier transform infrared spectroscopy(FTIR)spectrum.Characterization of the seeded cells was morphologically evaluated by scanning electron microscopy and by flow cytometry for the expression of the stem cell surface markers.The differentiation potential was verified after chondrogenic induction by analyzing the expression of chondrogenic marker genes using real-time(RT PCR).Current study suggest significant potential for the use of ADSCs with the nanofibrous scaffolds in improving the osteoarthritis pathology.

Adipose mesenchymal stem cell-derived extracellular vesicles reduce glutamate-induced excitotoxicity in the retina

Adipose mesenchymal stem cells(ADSCs)have protective effects against glutamate-induced excitotoxicity,but ADSCs are limited in use for treatment of optic nerve injury.Studies have shown that the extracellular vesicles(EVs)secreted by ADSCs(ADSC-EVs)not only have the function of ADSCs,but also have unique advantages including non-immunogenicity,low probability of abnormal growth,and easy access to target cells.In the present study,we showed that intravitreal injection of ADSC-EVs substantially reduced glutamate-induced damage to retinal morphology and electroretinography.In addition,R28 cell pretreatment with ADSC-EVs before injury inhibited glutamate-induced overload of intracellular calcium,downregulation ofα-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid receptor(AMPAR)subunit GluA2,and phosphorylation of GluA2 and protein kinase C alpha in vitro.A protein kinase C alpha agonist,12-O-tetradecanoylphorbol 13-acetate,inhibited the neuroprotective effects of ADSC-EVs on glutamate-induced R28 cells.These findings suggest that ADSCEVs ameliorate glutamate-induced excitotoxicity in the retina through inhibiting protein kinase C alpha activation.

Comparative effectiveness of adipose-derived mesenchymal stromal cells in the management of knee osteoarthritis:A meta-analysis

BACKGROUND Osteoarthritis(OA)is the most common joint disorder,is associated with an increasing socioeconomic impact owing to the ageing population.AIM To analyze and compare the efficacy and safety of bone-marrow-derived mesenchymal stromal cells(BM-MSCs)and adipose tissue-derived MSCs(AD-MSCs)in knee OA management from published randomized controlled trials(RCTs).METHODS Independent and duplicate electronic database searches were performed,including PubMed,EMBASE,Web of Science,and Cochrane Library,until August 2021 for RCTs that analyzed the efficacy and safety of AD-MSCs and BM-MSCs in the management of knee OA.The visual analog scale(VAS)score for pain,Western Ontario McMaster Universities Osteoarthritis Index(WOMAC),Lysholm score,Tegner score,magnetic resonance observation of cartilage repair tissue score,knee osteoarthritis outcome score(KOOS),and adverse events were analyzed.Analysis was performed on the R-platform using OpenMeta(Analyst)software.Twenty-one studies,involving 936 patients,were included.Only one study compared the two MSC sources without patient randomization;hence,the results of all included studies from both sources were pooled,and a comparative critical analysis was performed.RESULTS At six months,both AD-MSCs and BM-MSCs showed significant VAS improvement(P=0.015,P=0.012);this was inconsistent at 1 year for BM-MSCs(P<0.001,P=0.539),and AD-MSCs outperformed BM-MSCs compared to controls in measures such as WOMAC(P<0.001,P=0.541),Lysholm scores(P=0.006;P=0.933),and KOOS(P=0.002;P=0.012).BM-MSC-related procedures caused significant adverse events(P=0.003)compared to AD-MSCs(P=0.673).CONCLUSION Adipose tissue is superior to bone marrow because of its safety and consistent efficacy in improving pain and functional outcomes.Future trials are urgently warranted to validate our findings and reach a consensus on the ideal source of MSCs for managing knee OA.

High glucose microenvironment and human mesenchymal stem cell behavior

High glucose(HG)culture conditions in vitro and persistent exposure to hyperglycemia in diabetes patients are detrimental to stem cells,analogous to any other cell type in our body.It interferes with diverse signaling pathways,i.e.mammalian target of rapamycin(mTOR)-phosphoinositide 3-kinase(PI3K)-Akt signaling,to impact physiological cellular functions,leading to low cell survival and higher cell apoptosis rates.While elucidating the underlying mechanism responsible for the apoptosis of adipose tissue-derived mesenchymal stem cells(MSCs),a recent study has shown that HG culture conditions dysregulate mTORPI3K-Akt signaling in addition to mitochondrial malfunctioning due to defective mitochondrial membrane potential(MtMP)that lowers ATP production.This organelle-level dysfunction energy-starves the cells and increases oxidative stress and ultrastructural abnormalities.Disruption of the mitochondrial electron transport chain produces an altered mitochondrial NAD+/NADH redox state as evidenced by a low NAD+/NADH ratio that primarily contributes to the reduced cell survival in HG.Some previous studies have also reported altered mitochondrial membrane polarity(causing hyperpolarization)and reduced mitochondrial cell mass,leading to perturbed mitochondrial homeostasis.The hostile microenvironment created by HG exposure creates structural and functional changes in the mitochondria,altering their bioenergetics and reducing their capacity to produce ATP.These are significant data,as MSCs are extensively studied for tissue regeneration and restoring their normal functioning in cell-based therapy.Therefore,MSCs from hyperglycemic donors should be cautiously used in clinical settings for cell-based therapy due to concerns of their poor sur-vival rates and increased rates of post engraftment proliferation.As hypergly-cemia alters the bioenergetics of donor MSCs,rectifying the loss of MtMP may be an excellent target for future research to restore the normal functioning of MSCs in hyperglycemic patients.

Optimization of adipose tissue-derived mesenchymal stromal cells transplantation for bone marrow repopulation following irradiation

BACKGROUND Bone marrow(BM)suppression is one of the most common side effects of radiotherapy and the primary cause of death following exposure to irradiation.Despite concerted efforts,there is no definitive treatment method available.Recent studies have reported using mesenchymal stromal cells(MSCs),but their therapeutic effects are contested.AIM We administered and examined the effects of various amounts of adipose-derived MSCs(ADSCs)in mice with radiation-induced BM suppression.METHODS Mice were divided into three groups:Normal control group,irradiated(RT)group,and stem cell-treated group following whole-body irradiation(WBI).Mouse ADSCs(mADSCs)were transplanted into the peritoneal cavity either once or three times at 5×10^(5) cells/200μL.The white blood cell count and the levels of,plasma cytokines,BM mRNA,and BM surface markers were compared between the three groups.Human BM-derived CD34+hematopoietic progenitor cells were co-cultured with human ADSCs(hADSCs)or incubated in the presence of hADSCs conditioned media to investigate the effect on human cells in vitro.RESULTS The survival rate of mice that received one transplant of mADSCs was higher than that of mice that received three transplants.Multiple transplantations of ADSCs delayed the repopulation of BM hematopoietic stem cells.Anti-inflammatory effects and M2 polarization by intraperitoneal ADSCs might suppress erythropoiesis and induce myelopoiesis in sub-lethally RT mice.CONCLUSION The results suggested that an optimal amount of MSCs could improve survival rates post-WBI.

Immunomodulatory effects of mesenchymal stem cells derived from adipose tissues in a rat orthotopic liver transplantation model

BACKGROUND: Acute rejection after liver transplantation is usually treated with large doses of immunosuppressants with severe toxic and side-effects, so it is imperative to find a safe and effective method for preventing and treating rejection. This study was designed to confirm the immunomodulatory effects of rat mesenchymal stem cells (MSCs) in vitro and investigate the tolerogenic features in a rat model of allogeneic liver transplantation. METHODS: MSCs were isolated from adipose tissue of Sprague-Dawley (SD) rats and cultured. In vitro, MSCs were added into a mixed lymphocyte culture (MLC) system to study the inhibitory effects of MSCs on the proliferation of T lymphocytes in Wistar rats. By using SD and Wistar rats as liver donors and recipients, an orthotopic liver transplantation model was established and the rats were divided into a MSC-treated group and a blank control group. On postoperative day 7, all rats were sacrificed, and the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), interleukin-2 (IL-2) and interleukin-10 (IL-10) were measured. The pathological changes of liver tissue and apoptosis of hepatocytes were also assessed. RESULTS: In in vitro MLC, T lymphocyte proliferation in Wistar rats was significantly inhibited by 48.44%. In the MSC-treated group, the levels of ALT, AST, TBIL, IL-2 and IL-10 were 134.2 +/- 45.0 U/L, 162.5 +/- 30.5 U/L, 30.6 +/- 5.4 mu mol/L, 187.35 +/- 18.26 mu g/L and 193.95 +/- 37.62 mu g/L, and those in the blank control group were 355.6 +/- 54.3 U/L, 296.4 +/- 71.2 U/L, 145.7 +/- 28.6 +/- mol/L, 295.73 +/- 57.15 mu g/L and 75.12 +/- 11.23 mu g/L, respectively, with statistically significant differences (P<0.05). Pathological examination revealed that the rejection in the MSC-treated group was clearly alleviated compared with that in the blank control group. TUNEL indicated that the apoptosis of hepatocytes in the MSC-treated group was milder than that in the blank control group (P<0.05). CONCLUSION: Adipose-derived MSCs clearly inhibit recipient-derived T lymphocyte proliferation in MLC and significantly alleviate acute rejection following orthotopic liver transplantation in rats.

Hepatogenic differentiation of human mesenchymal stem cells from adipose tissue in comparison with bone marrow mesenchymal stem cells

AIM： To investigate and compare the hepatogenic transdifferentiation of adipose tissue-derived stem cells （ADSC） and bone marrow-derived mesenchymal stem cells （BMSC） in vitro. Transdifferentiation of BMSC into hepatic cells in vivo has been described. Adipose tissue represents an accessible source of ADSC, with similar characteristics to BMSC. METHODS： BMSCs were obtained from patients undergoing total hip arthroplasty and ADSC from human adipose tissue obtained from lipectomy. Cells were grown in medium containing 15% human serum. Cultures were serum deprived for 2 d before cultivating under similar pro-hepatogenic conditions to those of liver development using a 2-step protocol with sequential addition of growth factors, cytokines and hormones. Hepatic differentiation was RT-PCR-assessed and liver-marker genes were immunohistochemically analysed.RESULTS： BMSC and ADSC exhibited a fibroblastic morphology that changed to a polygonal shape when cells differentiated. Expression of stem cell marker Thyl decreased in differentiated ADSC and BMSC. However, the expression of the hepatic markers, albumin and CYPs increased to a similar extent in differentiated BMSC and ADSC. Hepatic gene activation could be attributed to increased liver-enriched transcription factors （C/EBPβ and HNF4α）, as demonstrated by adenoviral expression vectors.CONCLUSION： Mesenchymal stem cells can be induced to hepatogenic transdifferentiation in vitro. ADSCs have a similar hepatogenic differentiation potential to BMSC, but a longer culture period and higher proliferation capacity. Therefore, adipose tissue may be an ideal source of large amounts of autologous stem cells, and may become an alternative for hepatocyte regeneration, liver cell transplantation or preclinical drug testing.

Adipose tissue-derived stem cells as a therapeutic tool for cardiovascular disease

Adipose tissue-deried stem cells( ADSCs) are adult stem cells that can be easily harvested from subcutaneous adipose tissue. Many studies have demonstrated that ADSCs differentiate into vascular endothelial cells(VECs), vascular smooth muscle cells(VSMCs), and cardiomyocytes in vitro and in vivo. However, ADSCs may fuse with tissue-resident cells and obtain the corresponding characteristics of those cells. If fusion occurs, ADSCs may express markers of VECs, VSMCs, and cardiomyocytes without direct differentiation into these cell types. ADSCs also produce a variety of paracrine factors such as vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor-1 that have proangiogenic and/or antiapoptotic activities. Thus, ADSCs have the potential to regenerate the cardiovascular system via direct differentiation into VECs, VSMCs, and cardiomyocytes, fusion with tissueresident cells, and the production of paracrine factors. Numerous animal studies have demonstrated the efficacy of ADSC implantation in the treatment of acute myocardial infarction(AMI), ischemic cardiomyopathy(ICM), dilated cardiomyopathy, hindlimb ischemia, and stroke. Clinical studies regarding the use of autologous ADSCs for treating patients with AMI and ICM have recently been initiated. ADSC implantation has been reported as safe and effective so far. Therefore, ADSCs appear to be useful for the treatment of cardiovascular disease. However, the tumorigenic potential of ADSCs requires careful evaluation before their safe clinical application.

Adipose-derived mesenchymal stromal/stem cells: An update on their phenotype in vivo and in vitro

Adipose tissue is a rich, ubiquitous and easily acces-sible source for multipotent stromal/stem cells and has, therefore, several advantages compared to other sourc-es of mesenchymal stromal/stem cells. Several studies have tried to identify the origin of the stromal/stem cell population within adipose tissue in situ. This is a complicated attempt because no marker has currently been described which unambiguously identifies native adipose-derived stromal/stem cells(ASCs). Isolated and cultured ASCs are a non-uniform preparation consisting of several subsets of stem and precursor cells. Cultured ASCs are characterized by their expression of a panel of markers(and the absence of others), whereas their in vitro phenotype is dynamic. Some markers were ex-pressed de novo during culture, the expression of some markers is lost. For a long time, CD34 expression was solely used to characterize haematopoietic stem and progenitor cells, but now it has become evident that it is also a potential marker to identify an ASC subpopula-tion in situ and after a short culture time. Nevertheless, long-term cultured ASCs do not express CD34, perhaps due to the artificial environment. This review gives an update of the recently published data on the origin and phenotype of ASCs both in vivo and in vitro. In addition, the composition of ASCs(or their subpopula-tions) seems to vary between different laboratories andpreparations. This heterogeneity of ASC preparationsmay result from different reasons. One of the main problems in comparing results from different laborato-ries is the lack of a standardized isolation and culture protocol for ASCs. Since many aspects of ASCs, suchas the differential potential or the current use in clinical trials, are fully described in other recent reviews, this review further updates the more basic research issues concerning ASCs' subpopulations, heterogeneity andculture standardization.

Osteogenic potential: comparison between bone marrow and adipose-derived mesenchymal stem cells

Bone tissue engineering(BTE) is now a promising re-search issue to improve the drawbacks from traditional bone grafting procedure such as limited donor sources and possible complications. Stem cells are one of the major factors in BTE due to the capability of self re-newal and multi-lineage differentiation. Unlike embry-onic stem cells, which are more controversial in ethical problem, adult mesenchymal stem cells are considered to be a more appropriate cell source for BTE. Bone marrow mesenchymal stem cells(BMSCs) are the ear-liest-discovered and well-known stem cell source using in BTE. However, the low stem cell yield requiring long expansion time in vitro, pain and possible morbidities during bone marrow aspiration and poor proliferation and osteogenic ability at old age impede its' clinical ap-plication. Afterwards, a new stem cell source coming from adipose tissue, so-called adipose-derived stemcells(ASCs), is found to be more suitable in clinical ap-plication because of high stem cells yield from lipoaspi-rates, faster cell proliferation and less discomfort and morbidities during harvesting procedure. However, the osteogenic capacity of ASCs is now still debated be-cause most papers described the inferior osteogenesis of ASCs than BMSCs. A better understanding of the osteogenic differences between ASCs and BMSCs is crucial for future selection of cells in clinical application for BTE. In this review, we describe the commonality and difference between BMSCs and ASCs by cell yield, cell surface markers and multiple-differentiation poten-tial. Then we compare the osteogenic capacity in vitro and bone regeneration ability in vivo between BMSCs and ASCs based on the literatures which utilized both BMSCs and ASCs simultaneously in their articles. The outcome indicated both BMSCs and ASCs exhibited the osteogenic ability to a certain extent both in-vitro and in-vivo. However, most in-vitro study papers verified the inferior osteogenesis of ASCs; conversely, in-vivo research reviews revealed more controversies in this issue. We expect the new researchers can have a quick understanding of the progress in this filed and design a more comprehensive research based on this review.

Effect of adipose-derived mesenchymal stem cells on hepatocellular carcinoma: In vitro inhibition of carcinogenesis

AIM To investigate the effect of adipose-derived mesenchymal stem cells(ADMSCs)and their conditioned media(CM) on hepatocellular carcinoma(HCC) cell tumorigenesis.METHODS The proliferation rate of HepG2 and PLC-PRF-5 HCC cancer cells was measured using the trypan blue exclusion method and confirmed using the cell-counting kit8(commonly known as CCK-8) assay. Apoptosis was detected by flow cytometry using annexin V-FITC. Protein and mRNA expression was quantified by ELISA and real time PCR, respectively. Migration and invasion rates were performed by Transwell migration and invasion assays. Wound healing was examined to confirm the data obtained from the migration assays.RESULTS Our data demonstrated that when co-culturing HCC cell lines with ADMSCs or treating them with ADMSC CM, the HCC cell proliferation rate was significantly inhibited and the apoptosis rate increased. The decreased proliferation rate was accompanied by an upregulation of P53 and Retinoblastoma mRNA and a downregulation of c-Myc and hTERT mRNA levels. More notably, ADMSCs and their CM suppressed the expression of the two important markers of HCC carcinogenicity, alpha-fetoprotein and Des-gamma-carboxyprothrombin. In addition, the migration and invasion levels of HepG2 and PLC-PRF-5 cells significantly decreased, potentially through increased expression of the tissue inhibitor metalloproteinases TIMP-1, TIMP-2 and TIMP-3.CONCLUSION These findings shed new light on a protective and therapeutic role for ADMSCs and their CM in controlling HCC invasiveness and carcinogenesis.

Adipose-derived mesenchymal stem cells accelerate nerve regeneration and functional recovery in a rat model of recurrent laryngeal nerve injury

Medialization thyroplasty or injection laryngoplasty for unilateral vocal fold paralysis cannot restore mobility of the vocal fold. Recent studies have shown that transplantation of mesenchymal stem cells is effective in the repair of nerve injuries. This study investigated wheth- er adipose-derived stem celt transplantation could repair recurrent laryngeal nerve injury. Rat models of recurrent laryngeal nerve injury were established by crushing with micro forceps. Adipose-derived mesenchymal stem cells （ADSCs; 8 ×105） or differentiated Schwann-like adipose-derived mesenchymal stem cells （dADSCs; 8×105） or extracellular matrix were injected at the site of injury. At 2, 4 and 6 weeks post-surgery, a higher density of myelinated nerve fiber, thicker myelin sheath, improved vocal fold movement, better recovery of nerve conduction capacity and reduced thyroarytenoid muscle atrophy were found in ADSCs and dADSCs groups compared with the extracellu- lar matrix group. The effects were more pronounced in the ADSCs group than in the dADSCs group. These experimental results indicated that ADSCs transplantation could be an early interventional strategy to promote regeneration after recurrent laryngeal nerve injury.

Cell viability and extracellular matrix synthesis in a co-culture system of corneal stromal cells and adipose-derived mesenchymal stem cells

AIM：To investigate the impact of adipose-derived mesenchymal stem cells（ADSCs） on cell viability and extracellular matrix（ECM） synthesis of corneal stromal cells（CSCs）. METHODS：ADSCs and CSCs were obtained from the corneas of New Zealand white rabbits and indirectly cocultured in vitro. The proliferative capacity of CSCs in the different groups was assessed by CCK-8 assays. Annexin V-fluorescein isothiocyanate（FITC）/proliferation indices（PI） assays were used to detect the apoptosis of CSCs. The expression levels of matrix metalloproteinase（MMP）, such as MMP1, MMP2, MMP9, and collagens were also evaluated by Western blot. RESULTS：ADSCs significantly promoted proliferation and invasion of CSCs in the indirect co-culture assays. The co-cultural group displayed much higher ability of proliferation, especially under the co-culture conditions of ADSCs for 3d, compared with that CSCs cultured alone. The PI of CSCs in the co-culture system were increased approximately 3-8-fold compared with the control group. A significant change was observed in the proportions of cells at apoptosis（early and late） between the negative control group（6.34% and 2.06%） and the ADCSs-treated group（4.69% and 1.59%）. The expression levels of MMPs were down regulated in the co-culture models. Compared with the control group, the decrease intensities of MMP-1, MMP-2 and MMP-9 in CSCs/ADSCs group were observed, 3.90-fold, 1.09-fold and 3.03-fold, respectively. However, the increase intensities of collagen type（I, II, III, IV, and V） in CSCs were observed in CSCs/ADSCs group, 3.47-fold,4.30-fold, 2.35-fold, 2.55-fold and 2.43-fold, respectively, compared to that in the control group. The expressions of aldehyde dehydrogenase and fibronectin in CSCs were upregulated in the co-culture models.CONCLUSION：ADSCs play a promotive role in CSCs＇ growth and invasion, which may be partially associated with MMPs decrease and collagens increase, resulting in a positive participation in the plasticity and ECM synthesis of CSCs. This provided a new insight into the extensive role of ADSCs in CSCs and a potential molecular target for corneal therapy.