Photobiomodulation:a novel approach to promote trans-differentiation of adipose-derived stem cells into neuronal-like cells

Photobiomodulation,originally used red and near-infrared lasers,can alter cellular metabolism.It has been demonstrated that the visible spectrum at 451-540 nm does not necessarily increase cell proliferation,near-infrared light promotes adipose stem cell proliferation and affects adipose stem cell migration,which is necessary for the cells homing to the site of injury.In this in vitro study,we explored the potential of adipose-derived stem cells to differentiate into neurons for future translational regenerative treatments in neurodegenerative disorders and brain injuries.We investigated the effects of various biological and chemical inducers on trans-differentiation and evaluated the impact of photobiomodulation using 825 nm near-infrared and 525 nm green laser light at 5 J/cm2.As adipose-derived stem cells can be used in autologous grafting and photobiomodulation has been shown to have biostimulatory effects.Our findings reveal that adipose-derived stem cells can indeed trans-differentiate into neuronal cells when exposed to inducers,with pre-induced cells exhibiting higher rates of proliferation and trans-differentiation compared with the control group.Interestingly,green laser light stimulation led to notable morphological changes indicative of enhanced trans-differentiation,while near-infrared photobiomodulation notably increased the expression of neuronal markers.Through biochemical analysis and enzyme-linked immunosorbent assays,we observed marked improvements in viability,proliferation,membrane permeability,and mitochondrial membrane potential,as well as increased protein levels of neuron-specific enolase and ciliary neurotrophic factor.Overall,our results demonstrate the efficacy of photobiomodulation in enhancing the trans-differentiation ability of adipose-derived stem cells,offering promising prospects for their use in regenerative medicine for neurodegenerative disorders and brain injuries.

Immunomodulation of adipose-derived mesenchymal stem cells on peripheral blood mononuclear cells in colorectal cancer patients with COVID-19

BACKGROUND Accumulating evidence has shown that adipose tissue-derived mesenchymal stem cells(ADSCs)are an effective therapeutic approach for managing coronavirus disease 2019(COVID-19);however,further elucidation is required to determine their underlying immunomodulatory effect on the mRNA expression of T helper cell-related transcription factors(TFs)and cytokine release in peripheral blood mononuclear cells(PBMCs).AIM To investigate the impact of ADSCs on the mRNA expression of TFs and cytokine release in PBMCs from colorectal cancer(CRC)patients with severe COVID-19(CRC^(+)patients).METHODS PBMCs from CRC^(+)patients(PBMCs-C+)and age-matched CRC patients(PBMCs-C)were stimulated and cultured in the presence/absence of ADSCs.The mRNA levels of T-box TF TBX21(T-bet),GATA binding protein 3(GATA-3),RAR-related orphan receptor C(RORC),and forkhead box P3(FoxP3)in the PBMCs were determined by reverse transcriptase-polymerase chain reaction.Culture supernatants were evaluated for levels of interferon gamma(IFN-γ),interleukin 4(IL-4),IL-17A,and transforming growth factor beta 1(TGF-β1)using an enzyme-linked immunosorbent assay.RESULTS Compared with PBMCs-C,PBMCs-C+exhibited higher mRNA levels of T-bet and RORC,and increased levels of IFN-γ and IL-17A.Additionally,a significant decrease in FoxP3 mRNA and TGF-β1,as well as an increase in Tbet/GATA-3,RORC/FoxP3,IFN-γ/IL-4,and IL-17A/TGF-β1 ratios were observed in PBMCs-C+.Furthermore,ADSCs significantly induced a functional regulatory T cell(Treg)subset,as evidenced by an increase in FoxP3 mRNA and TGF-β1 release levels.This was accompanied by a significant decrease in the mRNA levels of T-bet and RORC,release of IFN-γ and IL-17A,and T-bet/GATA-3,RORC/FoxP3,IFN-γ/IL-4,and IL-17A/TGF-β1 ratios,compared with the PBMCs-C+alone.CONCLUSION The present in vitro studies showed that ADSCs contributed to the immunosuppressive effects on PBMCs-C+,favoring Treg responses.Thus,ADSC-based cell therapy could be a beneficial approach for patients with severe COVID-19 who fail to respond to conventional therapies.

Adipose-derived stem cells in diabetic foot care:Bridging clinical trials and practical application

Diabetic foot ulcers(DFUs)pose a critical medical challenge,significantly impairing the quality of life of patients.Adipose-derived stem cells(ADSCs)have been identified as a promising therapeutic approach for improving wound healing in DFUs.Despite extensive exploration of the mechanical aspects of ADSC therapy against DFU,its clinical applications remain elusive.In this review,we aimed to bridge this gap by evaluating the use and advancements of ADSCs in the clinical management of DFUs.The review begins with a discussion of the classification and clinical management of diabetic foot conditions.It then discusses the current landscape of clinical trials,focusing on their geographic distribution,reported efficacy,safety profiles,treatment timing,administration techniques,and dosing considerations.Finally,the review discusses the preclinical strategies to enhance ADSC efficacy.This review shows that many trials exhibit biases in study design,unclear inclusion criteria,and intervention protocols.In conclusion,this review underscores the potential of ADSCs in DFU treatment and emphasizes the critical need for further research and refinement of therapeutic approaches,with a focus on improving the quality of future clinical trials to enhance treatment outcomes and advance the field of diabetic wound care.

Etanercept-synthesizing adipose-derived stem cell secretome:A promising therapeutic option for inflammatory bowel disease

BACKGROUND Inflammatory bowel disease(IBD)is a chronic inflammatory condition of the gastrointestinal tract,with tumor necrosis factor(TNF)-αplaying a key role in its pathogenesis.Etanercept,a decoy receptor for TNF,is used to treat inflammatory conditions.The secretome derived from adipose-derived stem cells(ASCs)has anti-inflammatory effects,making it a promising therapeutic option for IBD.AIM To investigate the anti-inflammatory effects of the secretome obtained from ASCs synthesizing etanercept on colon cells and in a dextran sulfate sodium(DSS)-induced IBD mouse model.METHODS ASCs were transfected with etanercept-encoding mini-circle plasmids to create etanercept-producing cells.The secretory material from these cells was then tested for anti-inflammatory effects both in vitro and in a DSS-induced IBD mouse model.RESULTS This study revealed promising results indicating that the group treated with the secretome derived from etanercept-synthesizing ASCs[Etanercept-Secretome(Et-Sec)group]had significantly lower expression levels of inflammatory mediators,such as interleukin-6,Monocyte Chemoattractant Protein-1,and TNF-α,when compared to the control secretome(Ct-Sec).Moreover,the Et-Sec group exhibited a marked therapeutic effect in terms of preserving the architecture of intestinal tissue compared to the Ct-Sec.CONCLUSION These results suggest that the secretome derived from ASCs that synthesize etanercept has potential as a therapeutic agent for the treatment of IBD,potentially enhancing treatment efficacy by merging the anti-inflam-matory qualities of the ASC secretome with etanercept's targeted approach to better address the multifaceted pathophysiology of IBD.

Non-enzymatic methods for isolation of stromal vascular fraction and adipose-derived stem cells:A systematic review

BACKGROUND Adipose-derived stem cells(ADSCs)and the stromal vascular fraction(SVF)have garnered substantial interest in regenerative medicine due to their potential to treat a wide range of conditions.Traditional enzymatic methods for isolating these cells face challenges such as high costs,lengthy processing time,and regulatory complexities.AIM This systematic review aimed to assess the efficacy and practicality of nonenzymatic,mechanical methods for isolating SVF and ADSCs,comparing these to conventional enzymatic approaches.METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines,a comprehensive literature search was conducted across multiple databases.Studies were selected based on inclusion criteria focused on non-enzymatic isolation methods for SVF and ADSCs from adipose tissue.The risk of bias was assessed,and a qualitative synthesis of findings was performed due to the methodological heterogeneity of the included studies.RESULTS Nineteen studies met the inclusion criteria,highlighting various mechanical techniques such as centrifugation,vortexing,and ultrasonic cavitation.The review identified significant variability in cell yield and viability,and the integrity of isolated cells across different non-enzymatic methods compared to enzymatic procedures.Despite some advantages of mechanical methods,including reduced processing time and avoidance of enzymatic reagents,the evidence suggests a need for optimization to match the cell quality and therapeutic efficacy achievable with enzymatic isolation.CONCLUSION Non-enzymatic,mechanical methods offer a promising alternative to enzymatic isolation of SVF and ADSCs,potentially simplifying the isolation process and reducing regulatory hurdles.However,further research is necessary to standardize these techniques and ensure consistent,high-quality cell yields for clinical applications.The development of efficient,safe,and reproducible non-enzymatic isolation methods could significantly advance the field of regenerative medicine.

Exosomes from circ-Astn1-modified adipose-derived mesenchymal stem cells enhance wound healing through miR-138-5p/SIRT1/FOXO1 axis regulation

BACKGROUND Wound healing impairment is a dysfunction induced by hyperglycemia and its effect on endothelial precursor cells(EPCs)in type 2 diabetes mellitus.There is increasing evidence showing that exosomes(Exos)derived from adipose-derived mesenchymal stem cells(ADSCs)exhibit the potential to improve endothelial cell function along with wound healing.However,the potential therapeutic mechanism by which ADSC Exos contribute to wound healing in diabetic mice remains unclear.AIM To reveal the potential therapeutic mechanism of ADSC Exos in wound healing in diabetic mice.METHODS Exos from ADSCs and fibroblasts were used for high-throughput RNA sequencing(RNA-Seq).ADSC-Exo-mediated healing of full-thickness skin wounds in a diabetic mouse model was investigated.We employed EPCs to investigate the therapeutic function of Exos in cell damage and dysfunction caused by high glucose(HG).We utilized a luciferase reporter(LR)assay to analyze interactions among circular RNA astrotactin 1(circ-Astn1),sirtuin(SIRT)and miR-138-5p.A diabetic mouse model was used to verify the therapeutic effect of circ-Astn1 on Exo-mediated wound healing.RESULTS High-throughput RNA-Seq analysis showed that circ-Astn1 expression was increased in ADSC Exos compared with Exos from fibroblasts.Exos containing high concentrations of circ-Astn1 had enhanced therapeutic effects in restoring EPC function under HG conditions by promoting SIRT1 expression.Circ-Astn1 expression enhanced SIRT1 expression through miR-138-5p adsorption,which was validated by the LR assay along with bioinformatics analyses.Exos containing high concentrations of circ-Astn1 had better therapeutic effects on wound healing in vivo compared to wild-type ADSC Exos.Immunofluorescence and immunohistochemical investigations suggested that circ-Astn1 enhanced angiopoiesis through Exo treatment of wounded skin as well as by suppressing apoptosis through promotion of SIRT1 and decreased forkhead box O1 expression.CONCLUSION Circ-Astn1 promotes the therapeutic effect of ADSC-Exos and thus improves wound healing in diabetes via miR-138-5p absorption and SIRT1 upregulation.Based on our data,we advocate targeting the circ-Astn1/miR-138-5p/SIRT1 axis as a potential therapeutic option for the treatment of diabetic ulcers.

Advancements in adipose-derived stem cell therapy for skin fibrosis

Pathological scarring and scleroderma,which are the most common conditions of skin fibrosis,pathologically manifest as fibroblast proliferation and extracellular matrix(ECM)hyperplasia.Fibroblast proliferation and ECM hyperplasia lead to fibrotic tissue remodeling,causing an exaggerated and prolonged wound-healing response.The pathogenesis of these diseases has not been fully clarified and is unfortunately accompanied by exceptionally high medical needs and poor treatment effects.Currently,a promising and relatively low-cost treatment has emerged-adipose-derived stem cell(ASC)therapy as a branch of stem cell therapy,including ASCs and their derivatives-purified ASC,stromal vascular fraction,ASC-conditioned medium,ASC exosomes,etc.,which are rich in sources and easy to obtain.ASCs have been widely used in therapeutic settings for patients,primarily for the defection of soft tissues,such as breast enhancement and facial contouring.In the field of skin regeneration,ASC therapy has become a hot research topic because it is beneficial for reversing skin fibrosis.The ability of ASCs to control profibrotic factors as well as anti-inflammatory and immunomodulatory actions will be discussed in this review,as well as their new applications in the treatment of skin fibrosis.Although the long-term effect of ASC therapy is still unclear,ASCs have emerged as one of the most promising systemic antifibrotic therapies under development.

Hypoxic pre-conditioned adipose-derived stem/progenitor cells embedded in fibrin conduits promote peripheral nerve regeneration in a sciatic nerve graft model

Recent results emphasize the supportive effects of adipose-derived multipotent stem/progenitor cells(ADSPCs)in peripheral nerve recovery.Cultivation under hypoxia is considered to enhance the release of the regenerative potential of ADSPCs.This study aimed to examine whether peripheral nerve regeneration in a rat model of autologous sciatic nerve graft benefits from an additional custom-made fibrin conduit seeded with hypoxic pre-conditioned(2%oxygen for 72 hours)autologous ADSPCs(n=9).This treatment mode was compared with three others:fibrin conduit seeded with ADSPCs cultivated under normoxic conditions(n=9);non-cell-carrying conduit(n=9);and nerve autograft only(n=9).A 16-week follow-up included functional testing(sciatic functional index and static sciatic index)as well as postmortem muscle mass analyses and morphometric nerve evaluations(histology,g-ratio,axon density,and diameter).At 8 weeks,the hypoxic pre-conditioned group achieved significantly higher sciatic functional index/static sciatic index scores than the other three groups,indicating faster functional regeneration.Furthermore,histologic evaluation showed significantly increased axon outgrowth/branching,axon density,remyelination,and a reduced relative connective tissue area.Hypoxic pre-conditioned ADSPCs seeded in fibrin conduits are a promising adjunct to current nerve autografts.Further studies are needed to understand the underlying cellular mechanism and to investigate a potential application in clinical practice.

Assessment of the effects of intrastromal injection of adipose-derived stem cells in keratoconus patients

·AIM: To evaluate the efficacy and safety of intrastromal transplantation of adipose-derived stem cells(ASCs) in keratoconus patients.·METHODS: This study was conducted on 8 eyes of 8 patients with moderate to severe keratoconus. In the patients, ophthalmic assessments including visual acuity, refraction, slit lamp examination, fundoscopy, corneal topography, and confocal microscopy were performed. Autologous stem cells were used. The isolated stem cells were injected into the corneal stroma by using femtosecond laser. Surgical procedure was similar to intracorneal ring implantation. All patients were re-assessed 1, 3, and 6mo after surgery.·RESULTS: The baseline mean visual acuity was 0.48±0.18 and improved to 0.66±0.17 after surger y and final acuity increased by 1.85±0.80 lines(P=0.001).The mean spherical refraction of patients improved 0.34 ± 0.35 D(P=0.039), and the mean cylindrical refraction of patients improved 0.84±0.23 D(P=0.016). The mean flat keratometry decreased 0.78±0.71 D(P=0.017), and the mean steep keratometry decreased 0.59±0.68 D(P=0.023). The mean central corneal thickness of patients improved of 6.29±4.47 μm(P=0.03). The mean keratocyte density at the anterior and middle stroma of cornea increased(P<0.05) but remained stable at the posterior stroma after 6mo. All patients had no complications and their corneas remained transparent. ·CONCLUSION: Intrastromal transplantation of ASCs has positive effects on vision and refractive parameters in most patients with keratoconus. After six months, visual acuity improved moderately, corneal parameters reduced slightly, and stromal keratocytes density increased. This modality is safe, and patients do not have any complications.

Chitosan conduits enriched with fibrin-collagen hydrogel with or without adipose-derived mesenchymal stem cells for the repair of 15-mm-long sciatic nerve defect

Hollow conduits of natural or synthetic origins have shown acceptable regeneration results in short nerve gap repair;however,results are still not comparable with the current gold standard technique“autografts”.Hollow conduits do not provide a successful regeneration outcome when it comes to critical nerve gap repair.Enriching the lumen of conduits with different extracellular materials and cells could provide a better biomimicry of the natural nerve regenerating environment and is expected to ameliorate the conduit performance.In this study,we evaluated nerve regeneration in vivo using hollow chitosan conduits or conduits enriched with fibrin-collagen hydrogels alone or with the further addition of adipose-derived mesenchymal stem cells in a 15 mm rat sciatic nerve transection model.Unexpected changes in the hydrogel consistency and structural stability in vivo led to a failure of nerve regeneration after 15 weeks.Nevertheless,the molecular assessment in the early regeneration phase(7,14,and 28 days)has shown an upregulation of useful regenerative genes in hydrogel enriched conduits compared with the hollow ones.Hydrogels composed of fibrin-collagen were able to upregulate the expression of soluble NRG1,a growth factor that plays an important role in Schwann cell transdifferentiation.The further enrichment with adipose-derived mesenchymal stem cells has led to the upregulation of other important genes such as ErbB2,VEGF-A,BDNF,c-Jun,and ATF3.

Mechanism of adipose-derived mesenchymal stem cell exosomes in the treatment of heart failure

BACKGROUND Heart failure(HF)is a global health problem characterized by impaired heart function.Cardiac remodeling and cell death contribute to the development of HF.Although treatments such as digoxin and angiotensin receptor blocker drugs have been used,their effectiveness in reducing mortality is uncertain.Researchers are exploring the use of adipose-derived mesenchymal stem cell(ADMSC)exosomes(Exos)as a potential therapy for HF.These vesicles,secreted by cells,may aid in tissue repair and regulation of inflammation and immune responses.However,further investigation is needed to understand the specific role of these vesicles in HF treatment.AIM To investigate the mechanism of extracellular vesicles produced by ADMSC s in the treatment of HF.METHODS Exogenous surface markers of ADMSCs were found,and ADMSCs were cultured.RESULTS The identification of surface markers showed that the surface markers CD44 and CD29 of adipose-derived stem cells(ADSCs)were well expressed,while the surface markers CD45 and CD34 of ADSCs were negative,so the cultured cells were considered ADSCs.Western blotting detected the Exo surface marker protein,which expressed CD63 protein but did not express calnexin protein,indicating that ADSC-derived Exos were successfully extracted.CONCLUSION The secretion of MSCs from adipose tissue can increase ATP levels,block cardiomyocyte apoptosis,and enhance the heart function of animals susceptible to HF.The inhibition of Bax,caspase-3 and p53 protein expression may be related to this process.

Exercise combined with administration of adipose-derived stem cells ameliorates neuropathic pain after spinal cord injury

Experimental studies have shown that exercise and human adipose-derived stem cells(ADSCs)play positive roles in spinal cord injury(SCI).However,whether ADSCs and/or exercise have a positive effect on SCI-induced neuropathic pain is still unclear.Thus,there is a need to explore the effects of exercise combined with administration of ADSCs on neuropathic pain after SCI.In this study,a thoracic 11(T11)SCI contusion model was established in adult C57BL/6 mice.Exercise was initiated from 7 days post-injury and continued to 28 days post-injury,and approximately 1×105 ADSCs were transplanted into the T11 spinal cord lesion site immediately after SCI.Motor function and neuropathic pain-related behaviors were assessed weekly using the Basso Mouse Scale,von Frey filament test,Hargreaves method,and cold plate test.Histological studies(Eriochrome cyanine staining and immunohistochemistry)were performed at the end of the experiment(28 days post-injury).Exercise combined with administration of ADSCs partially improved early motor function(7,14,and 21 days postinjury),mechanical allodynia,mechanical hypoalgesia,thermal hyperalgesia,and thermal hypoalgesia.Administration of ADSCs reduced white and gray matter loss at the lesion site.In addition,fewer microglia and astrocytes(as identified by expression of ionized calcium-binding adapter molecule 1 and glial fibrillary acidic protein,respectively)were present in the lumbar dorsal horn in the SCI+ADSCs and SCI+exercise+ADSCs groups compared with the sham group.Our findings suggest that exercise combined with administration of ADSCs is beneficial for the early recovery of motor function and could partially ameliorate SCIinduced neuropathic pain.

Role of adipose-derived stem cells in breast cancer

The clinical use of fat grafts for breast reconstruction post-mastectomy or radiotherapy has the disadvantages of limited retention and survival rates.To solve this problem,adipose-derived stem cells(ADSCs)have been suggested as an alternative cell source for breast reconstruction,because they are simple to access,have low immunogenicity,and support the survival of mature adipose grafts.However,despite their outstanding properties,the use of ADSCs in patients with breast cancer is controversial,and the oncological safety of this method has been questioned.The biological effects of ADSCs on breast cancer are complex,and clinical research on ADSC-assisted fat grafting is limited.Here,we review the current experimental findings on the effects of ADSCs on breast cancer,mainly focusing on the role of ADSCs in breast cancer proliferation and growth processes,such as epithelial-mesenchymal transition(EMT)and angiogenesis.We also discuss the safety of ADSCs in clinical breast reconstruction.

0Adipose-derived stem cells: Implications in tissue regeneration

Adipose-derived stem cells(ASCs) are mesenchymal stem cells(MSCs) that are obtained from abundant adipose tissue, adherent on plastic culture flasks, can be expanded in vitro, and have the capacity to differ-entiate into multiple cell lineages. Unlike bone marrow-derived MSCs, ASCs can be obtained from abundant adipose tissue by a minimally invasive procedure, which results in a high number of cells. Therefore, ASCs are promising for regenerating tissues and organs dam-aged by injury and diseases. This article reviews the implications of ASCs in tissue regeneration.

Current applications of adipose-derived stem cells and their future perspectives

Adult stem cells have a great potential to treat various diseases. For these cell-based therapies, adipose-derived stem cells(ADSCs) are one of the most promising stem cell types, including embryonic stem cells(ESCs) and induced pluripotent stem cells(iPSCs). ESCs and iPSCs have taken center stage due to their pluripotency. However, ESCs and iPSCs have limitations in ethical issues and in identification of characteristics, respectively. Unlike ESCs and iPSCs, ADSCs do not have such limitations and are not only easily obtained but also uniquely expandable. ADSCs can differentiate into adipocytes, osteoblasts, chondrocytes, myocytes and neurons under specific differentiation conditions, and these kinds of differentiation potential of ADSCs could be applied in regenerative medicine e.g., skin reconstruction, bone and cartilage formation, etc. In this review, the current status of ADSC isolation, differentiation and their therapeutic applications are discussed.

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.

In vitro differentiation of adipose-derived stem cells and bone marrow-derived stromal stem cells into neuronal-like cells

Adipose-derived stem cells and bone marrow-derived stromal stem cells were co-cultured with untreated or Aβ1-40-treated PC12 cells, or grown in supernatant derived from untreated or Aβ1-40-treated PC12 cells. Analysis by western blot and quantitative real-time PCR showed that protein levels of Nanog, Oct4, and Sox2, and mRNA levels of miR/125a/3p were decreased, while expression of insulin-like growth factor-2 and neuron specific enolase was increased. In comparison the generation of neuron specific enolase-positive cells was most successful when adipose-derived stem cells were co-cultured with Aβ1-40-treated PC12 cells. Our results demonstrate that adipose-derived stem cells and bone marrow-derived stromal stem cells exhibit trends of neuronal-like cell differentiation after co-culture with Aβ1-40-treated PC12 cells. This process may relate to a downregulation of miR-125a-3p mRNA expression and increased levels of insulin-like growth factor-2 expression.

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.

Bone marrow-derived mesenchymal stem cells versus adipose-derived mesenchymal stem cells for peripheral nerve regeneration

Studies have confirmed that bone marrow-derived mesenchymal stem cells （MSCs） can be used for treatment of several nervous system diseases. However, isolation of bone marrow-derived MSCs （BMSCs） is an invasive and painful process and the yield is very low. Therefore, there is a need to search for other alterative stem cell sources. Adipose-derived MSCs （ADSCs） have phenotypic and gene expression profiles similar to those of BMSCs. The production of ADSCs is greater than that of BMSCs, and ADSCs proliferate faster than BMSCs. To compare the effects of venous grafts containing BMSCs or ADSCs on sciatic nerve injury, in this study, rats were randomly divided into four groups： sham （only sciatic nerve exposed）, Matrigel （MG; sciatic nerve injury ＋ intravenous transplantation of MG vehicle）, ADSCs （sciatic nerve injury ＋ intravenous MG containing ADSCs）, and BMSCs （sciatic nerve injury ＋ intravenous MG containing BMSCs） groups. Sciatic functional index was calculated to evaluate the function of injured sciatic nerve. Morphologic characteristics of nerves distal to the lesion were observed by toluidine blue staining. Spinal motor neurons labeled with Fluoro-Gold were quantitatively assessed. Compared with sham-operated rats, sciatic functional index was lower, the density of small-diameter fibers was significantly increased, and the number of motor neurons significantly decreased in rats with sciatic nerve injury. Neither ADSCs nor BMSCs significantly improved the sciatic nerve function of rats with sciatic nerve injury,increased fiber density, fiber diameters, axonal diameters, myelin sheath thickness, and G ratios （axonal diameter/fiber diameter ratios） in the sciatic nerve distal to the lesion site. There was no significant difference in the number of spinal motor neurons among ADSCs, BMSCs and MG groups. These results suggest that neither BMSCs nor ADSCs provide satisfactory results for peripheral nerve repair when using MG as the conductor for engraftment.

Adipose-derived mesenchymal stem cell transplantation promotes adult neurogenesis in the brains of Alzheimer's disease mice

In the present study, we transplanted adipose-derived mesenchymal stem cells into the hippo-campi of APP/PS1 transgenic Alzheimer＇s disease model mice. Immunofluorescence staining revealed that the number of newly generated （BrdU＋） cells in the subgranular zone of the dentate gyrus in the hippocampus was signiifcantly higher in Alzheimer＇s disease mice after adipose-de-rived mesenchymal stem cell transplantation, and there was also a significant increase in the number of BrdU＋/DCX＋neuroblasts in these animals. Adipose-derived mesenchymal stem cell transplantation enhanced neurogenic activity in the subventricular zone as well. Furthermore, adipose-derived mesenchymal stem cell transplantation reduced oxidative stress and alleviated cognitive impairment in the mice. Based on these ifndings, we propose that adipose-derived mes-enchymal stem cell transplantation enhances endogenous neurogenesis in both the subgranular and subventricular zones in APP/PS1 transgenic Alzheimer＇s disease mice, thereby facilitating functional recovery.