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.

High-Fat Diets-Induced Metabolic Alterations Alter the Differentiation Potential of Adipose Tissue-Derived Stem Cells

Background: Adipose tissue-derived stem cells (ASC) possess the ability to differentiate into adipocytes or endothelial cells to help in the adipogenesis, vasculogenesis and vascular repair. This study aims at determining the impact of high-fat diets (HFD)-induced type 2 diabetes (T2D) on the differentiation potential of ASC. Results: C57BL/6J male mice were fed a vegetal (VD) or an animal (AD) HFD. Isolation of ACS from mice showing different levels of metabolic alterations reveals that advanced T2D did not affect the number of cells per gram of tissue. Rather, a higher proportion of inflammatory CD36+ cells was identified in HFD fed mice. Despite a marked decreased expression of adipogenic genes (aP2, C/EBPα and PPARγ2), ASC from HFD groups had a higher adipogenic potential and a lower endothelial differentiation potential in vitro compared to control. ASC from the VD group had enhanced cyclin B1 expression and had more adipogenic potential compared to AD group. Conclusion: Our results demonstrate that the metabolic modifications, linked to the nature of fatty acids in diets, modulate the differentiation potential of ASC with increased adipogenesis to the detriment of the endothelial pathway. Results highlight the importance of evaluating the ASC differentiation behavior in a context of autologous cell-based therapy for the repair of vascular tissues in diabetic 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.

Transplantation of neural progenitor cells differentiated from adipose tissue-derived stem cells for treatment of sciatic nerve injury

Objectives: Currently, the clinical repair of sciatic nerve injury remains difficult.Previous studies have confirmed that transplantation of adipose tissue-derived stem cells promotes nerve regeneration and restoration at peripheral nerve injury sites. Methods: In this study, adipose tissue-derived stem cells were induced to differentiate into neural progenitor cells, transfected with a green fluorescent protein-containing lentivirus, and then transplanted into the lesions of rats with sciatic nerve compression injury. Results: Fluorescence microscopy revealed that the transplanted cells survived,migrated, and differentiated in rats. At two weeks post-operation, a large number of transplanted cells had migrated to the injured lesions; at six weeks post-operation, transplanted cells were visible around the injured nerve and several cells were observed to express a Schwann cell marker. Sciatic function index and electrophysiological outcomes of the transplantation group were better than those of the control group. Cell transplantation promoted the recovery of motor nerve conduction velocity and compound muscle action potential amplitude, and reduced gastrocnemius muscle atrophy.Conclusions: Our experimental findings indicate that neural progenitor cells,differentiated from adipose tissue-derived stem cells, are potential seed stem cells that can be transplanted into lesions to treat sciatic nerve injury. This provides a theoretical basis for their use in clinical applications.

Chemically induced hypoxia by dimethyloxalylglycine(DMOG)-loaded nanoporous silica nanoparticles supports endothelial tube formation by sustained VEGF release from adipose tissue-derived stem cells

Inadequate vascularization leading to insufficient oxygen and nutrient supply in deeper layers of bioartificial tissues remains a limitation in current tissue engineering approaches to which prevascularization offers a promising solution.Hypoxia triggering pre-vascularization by enhanced vascular endothelial growth factor(VEGF)expression can be induced chemically by dimethyloxalylglycine(DMOG).Nanoporous silica nanoparticles(NPSNPs,or mesoporous silica nanoparticles,MSNs)enable sustained delivery of molecules and potentially release DMOG allowing a durable capillarization of a construct.Here we evaluated the effects of soluble DMOG and DMOG-loaded NPSNPs on VEGF secretion of adipose tissue-derived stem cells(ASC)and on tube formation by human umbilical vein endothelial cells(HUVEC)-ASC co-cultures.Repeated doses of 100 mM and 500 mM soluble DMOG on ASC resulted in 3-to 7-fold increased VEGF levels on day 9(P<0.0001).Same doses of DMOG-NPSNPs enhanced VEGF secretion 7.7-fold(P<0.0001)which could be maintained until day 12 with 500 mM DMOG-NPSNPs.In fibrin-based tube formation assays,100 mM DMOG-NPSNPs had inhibitory effects whereas 50 mM significantly increased tube length,area and number of junctions transiently for 4 days.Thus,DMOG-NPSNPs supported endothelial tube formation by upregulated VEGF secretion from ASC and thus display a promising tool for prevascularization of tissue-engineered constructs.Further studies will evaluate their effect in hydrogels under perfusion.

Hepatic perivascular epithelioid cell tumors:The importance of preoperative diagnosis

Accurate preoperative diagnosis is highly important for the treatment of perivascular epithelioid cell tumors(PEComas)because PEComas are mainly benign tumors and may not require surgical intervention.By analyzing the causes,properties and clinical manifestations of PEComas,we summarize the challenges and solutions in the diagnosis of PEComas.

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.

Unmodified autologous stem cells at point of care for chronic myocardial infarction

BACKGROUND Numerous studies investigated cell-based therapies for myocardial infarction(MI).The conflicting results of these studies have established the need for developing innovative approaches for applying cell-based therapy for MI.Experimental studies on animal models demonstrated the potential of fresh,uncultured,unmodified,autologous adipose-derived regenerative cells(UAADRCs)for treating acute MI.In contrast,studies on the treatment of chronic MI(CMI;>4 wk post-MI)with UA-ADRCs have not been published so far.Among several methods for delivering cells to the myocardium,retrograde delivery into a temporarily blocked coronary vein has recently been demonstrated as an effective option.AIM To test the hypothesis that in experimentally-induced chronic myocardial infarction(CMI;>4 wk post-MI)in pigs,retrograde delivery of fresh,uncultured,unmodified,autologous adipose-derived regenerative cells(UA-ADRCs)into a temporarily blocked coronary vein improves cardiac function and structure.METHODS The left anterior descending(LAD)coronary artery of pigs was blocked for 180 min at time point T0.Then,either 18×106 UA-ADRCs prepared at“point of care”or saline as control were retrogradely delivered via an over-the-wire balloon catheter placed in the temporarily blocked LAD vein 4 wk after T0(T1).Effects of cells or saline were assessed by cardiac magnetic resonance(CMR)imaging,late gadolinium enhancement CMR imaging,and post mortem histologic analysis 10 wk after T0(T2).RESULTS Unlike the delivery of saline,delivery of UA-ADRCs demonstrated statistically significant improvements in cardiac function and structure at T2 compared to T1(all values given as mean±SE):Increased mean LVEF(UA-ADRCs group:34.3%±2.9%at T1 vs 40.4±2.6%at T2,P=0.037;saline group:37.8%±2.6%at T1 vs 36.2%±2.4%at T2,P>0.999),increased mean cardiac output(UA-ADRCs group:2.7±0.2 L/min at T1 vs 3.8±0.2 L/min at T2,P=0.002;saline group:3.4±0.3 L/min at T1 vs 3.6±0.3 L/min at T2,P=0.798),increased mean mass of the left ventricle(UA-ADRCs group:55.3±5.0 g at T1 vs 71.3±4.5 g at T2,P<0.001;saline group:63.2±3.4 g at T1 vs 68.4±4.0 g at T2,P=0.321)and reduced mean relative amount of scar volume of the left ventricular wall(UA-ADRCs group:20.9%±2.3%at T1 vs 16.6%±1.2%at T2,P=0.042;saline group:17.6%±1.4%at T1 vs 22.7%±1.8%at T2,P=0.022).CONCLUSION Retrograde cell delivery of UA-ADRCs in a porcine model for the study of CMI significantly improved myocardial function,increased myocardial mass and reduced the formation of scar tissue.

Stem cell therapy for erectile dysfunction

Erectile dysfunction(ED)is an important health problem that has commonly been clinically treated using phosphodiesterase type 5 inhibitors(PDE5Is).However,PDE5Is are less effective when the structure of the cavernous body has been severely injured,and thus regeneration is required.Stem cell therapy has been investigated as a possible means for regenerating the injured cavernous body.Stem cells are classified into embryonic stem cells and adult stem cells(ASCs),and the intracavernous injection of ASCs has been explored as a therapy in animal ED models.Bone marrowderived mesenchymal stem cells and adipose tissuederived stem cells are major sources of ASCs used for the treatment of ED,and accumulated evidence now suggests that ASCs are useful in the restoration of erectile function and the regeneration of the cavernous body.However,the mechanisms by which ASCs recover erectile function remain controversial.Some studies indicated that ASCs were differentiated into the vascular endothelial cells,vascular smooth muscle cells,and nerve cells that originally resided in the cavernous body,whereas other studies have suggested that ASCs improved erectile function via the secretion of anti-apoptotic and/or proangiogenic cytokines ratherthan differentiation into other cell types.In this paper,we reviewed the characteristics of stem cells used for the treatment of ED,and the possible mechanisms by which these cells exert their effects.We also discussed the problems to be solved before implementation in the clinical setting.

The CD133/1⁺cell subset from human subcutaneous adult fat retains hemogenic potential

Research has shown that cells from adult fat tissue can effect long-term blood reconstitution. Fat-derived multipotentiality was ascribed to CD34+ perivascular populations from its prominent microvasculature, that represent mostly non-hemogenic, mesenchymal cells, although this tissue contains a CD34+45+ subset committed to a hemogenic fate. Here, in order to analyze cell subsets presenting hemogenic capabilities within fat, CD133/1+ and pericytes, the latter defined by CD140b (PDGFRb, Platelet-Derived Growth Factor Receptor Beta) expression, were immunomagnetically selected from stromal-vascular fractions (SVF). In Vitro Colony Forming Unit (CFU) assays were negative for CD140b+ pericytes and positive for CD133/1+ cells when a prolonged CFU assay was performed, revealing fat as another store of primitive progenitors that retain hemogenic potential.

Strategies for Human Adipose Tissue Repair and Regeneration

In plastic and reconstructive surgery there is an increasing demand for malleable implants to repair soft tissue congenital defects, or those resulting from aging, traumatic injury and tumour resection. However, currently available methods present a number of limitations such as volume loss over time and eventual resorption of the graft. Tissue engineering techniques provide promising therapeutic solutions to these inconveniences through development of engineered equivalents that best imitate adipose tissue, both structurally and functionally. Here we review the latest achievements in the human adipose tissue engineering field, with a focus on its regenerative potential for a number of clinical applications.

Current Status of ADSCs-Enriched Fat Grafts in Plastic Surgery

Autologous fat grafting is an increasingly popular technique in plastic surgery for volume augmentation and rejuvenation.However,the unpredictability of long-term volume retention limits its clinical application.Various animal studies have documented the positive effects of adipose tissue-derived stem cells(ADSCs)on the acceleration of lipofilling.However,the results have been inconsistent,and there is an insufficient number of high-quality clinical studies to formulate evidence-based recommendations for ADSC-enriched fat grafts.Moreover,related technical standards,such as the final count of harvested ADSCs and the enrichment ratio,have not yet been established.This systematic review included all clinical trials on ADSC-enriched fat grafts in plastic surgery from PubMed in the past 10 years,as well as all registered clinical trials on ClinicalTrials.Gov.To examine the current landscape of ADSCs harvest,we summarize the current applications of ADSCs in the field of plastic surgery and discuss the current barriers to universal clinical use.