Current Strategies to Enhance Adipose Stem Cell Function: An Update

Baseline magnetic resonance imaging findings associated with short-term clinical outcomes after intraarticular administration of autologous adipose-derived stem cells for knee osteoarthritis

Introduction

This study aimed to determine the association between the baseline magnetic resonance imaging (MRI) findings and clinical outcomes after articular injection of adipose-derived mesenchymal stem cells (ASCs) for knee osteoarthritis (KOA).

Methods

This retrospective study included 149 patients with varus-type KOA treated with a single intraarticular ASC injection. All patients underwent a MRI evaluation before treatment. Patients were categorized following the MRI Osteoarthritis Knee Score (MOAKS) system cartilage score into the mild, moderate, or severe KOA groups. Additionally, joint effusion and synovitis, bone marrow lesions (BMLs), and meniscal extrusions were graded with the MOAKS. Knee Osteoarthritis Outcome Score (KOOS) was obtained at baseline, 1-, 3-, 6-, and 12-month posttreatment. The responder rate in the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International was assessed with the KOOS. Multivariate logistic regression analyses were conducted to determine factors associated with the responder rate.

Results

All KOOS subscales significantly enhanced with the greatest improvement from baseline to 6 months which plateaued between 6 and 12 months. The responder rate was 65.4 % in the mild/moderate KOA compared to 35.2 % in the severe KOA at 12 months. Lower OA grade (odds ratio [OR]: 0.52; 95 % confidence interval (CI): 0.31-0.88; P = 0.015), smaller BMLs in medial femoral condyle (OR: 0.36; 95 % CI: 0.14-0.94; P = 0.037), and less meniscal extrusion (OR: 0.31; 95 % CI: 0.11-0.89; P = 0.029) were associated with higher responder rate at 6 months in multivariable logistic regression analysis. The factors associated with higher responder rate at 12 months included lower OA grade (OR: 0.42; 95 % CI: 0.25-0.73; P = 0.002) and younger age (OR: 1.04; 95 % CI: 1.00-1.08; P = 0.042).

Conclusions

ASC treatment for KOA enhanced short-term clinical outcomes. MRI findings, including cartilage lesions, BMLs, and meniscal extrusion, were associated with responder rate, helping physicians identify which patients may benefit from this therapy.

Effect of short-term gravitational changes on the human minor salivary gland stem cell characteristics

OBJECTIVES

Human minor salivary gland stem cells (huMSGSCs) are promising in regenerative medicine. Their multipotent capabilities enable tissue regeneration and offer treatment potential for various diseases. The effects of hypergravity (HyperG) and microgravity (MicroG) on stemness and therapeutic potential are not well explored. Therefore, this study investigated the effects of short-term HyperG and MicroG exposure on huMSGSC stemness and differentiation potential for treating salivary gland dysfunction.

METHODS

huMSGSCs were exposed to 1G, MicroG, and HyperG. Cell morphology, proliferation, sphere formation, and differentiation potential were analyzed. Stem cell and tight junction markers were evaluated using flow cytometry, real-time PCR, Western blot, and immunofluorescence analysis.

RESULTS

huMSGSCs showed fibroblast-like morphology and robust proliferation up to passage 10. Differentiation into adipocytes, chondrocytes, and osteocytes was successful, despite enhanced lineage-specific marker expression. HyperG significantly increased proliferation at 48 and 72 h, MicroG-exposed cells formed more numerous and smaller spheres, and HyperG-exposed cells produced larger spheres. HyperG elevated stem cell marker (CD90, LGR5, SOX2) expression levels, and the expression of tight junction protein expressions (ZO-1, ZO-2) was higher under HyperG treatment.

CONCLUSIONS

Short-term HyperG and MicroG exposure differentially influenced huMSGSC stemness and differentiation potential. HyperG enhanced proliferation, stem cell marker expression, and differentiation capacity. These findings suggest the potential of optimizing huMSGSCs for regenerative therapies that target salivary gland dysfunction and other tissue regeneration applications.

The Potential of Mesenchymal Stem Cell-Derived Exosomes to Treat Diabetes Mellitus

Diabetes mellitus (DM) is a fatal metabolic disease characterized by persistent hyperglycemia. In recent studies, mesenchymal stem cell (MSC)-derived exosomes, which are being investigated clinically as a cell-free therapy for various diseases, have gained attention due to their biomimetic properties that closely resemble natural cellular communication systems. These MSC-derived exosomes inherit the regenerative and protective effects from MSCs, inducing pancreatic β-cell proliferation and inhibiting apoptosis, as well as ameliorating insulin resistance by suppressing the release of various inflammatory cytokines. Consequently, MSC-derived exosomes have attracted attention as a novel treatment for DM as an alternative to stem cell therapy. In this review, we will introduce the potential of MSC-derived exosomes for the treatment of DM by discussing the studies that have used MSC-derived exosomes to treat DM, which have shown therapeutic effects in both type 1 and type 2 DM.

De novo interleukin-10 production primed by Lactobacillus sakei CVL-001 amplifies the immunomodulatory abilities of mesenchymal stem cells to alleviate colitis

Mesenchymal stem cells (MSCs) hold therapeutic promise for treating inflammatory bowel disease (IBD) owing to their immunomodulatory properties. Currently, pre-conditioning strategies with several beneficial agents have been applied to enhance the efficacy of MSCs in treating IBDs. Probiotics are increasingly acknowledged as supplemental therapy for IBD; however, their potential benefits in MSCs-based therapy remain largely unexplored. In this study, we hypothesized that pretreating MSCs with Lactobacillus sakei CVL-001 (L. sakei CVL-001), a representative probiotic strain, could improve their therapeutic effectiveness for IBD. In line with this hypothesis, we noted that pretreatment with L. sakei CVL-001 significantly induced IL-10 secretion in MSCs via the activation of the STAT3 signaling pathway. These primed MSCs reduced pro-inflammatory cytokine production in LPS/IFN-γ-treated macrophages and promoted an M2 phenotype, associated with immunoregulation and tissue repair, in undifferentiated macrophages. In addition, their conditioned media significantly reduced the proliferation capacity of Jurkat T cells and splenocytes, while the neutralization of IL-10 reversed these phenomena. Furthermore, MSCs treated with L. sakei CVL-001 mitigated inflammatory responses and promoted epithelial regeneration, leading to accelerated recovery from disease symptoms and improved survival rates compared to naive MSCs in a DSS-induced colitis mouse model. In conclusion, our findings suggest that probiotics, such as L. sakei CVL-001, can improve the therapeutic efficacy of MSCs for treating IBD.

Adipose Mesenchymal Stem Cell-Derived Exosomes as Nanocarriers for Treating Musculoskeletal Disorders

Musculoskeletal disorders are a series of diseases involving bone, muscle, cartilage, and tendon, mainly caused by chronic strain, degenerative changes, and structural damage due to trauma. The disorders limit the function of patients due to pain and significantly reduce their quality of life. In recent years, adipose-derived mesenchymal stem cells have been extensively applied in regeneration medicine research due to their particular abilities of self-renewal, differentiation, and targeted homing and are more easily accessed compared with other sources. The paracrine effect of ADSCs plays a crucial role in intercellular communication by releasing mass mediators, including cytokines and growth factors, particularly the exosomes they secrete. Not only do these exosomes possess low immunogenicity, low toxicity, and an enhanced ability to penetrate a bio-barrier, but they also inherit their parent cells' characteristics and carry various bioactive molecules to release to targeted cells, modulating their biological process. Meanwhile, these characteristics also make exosomes a natural nanocarrier capable of targeted drug delivery to specific sites, enhancing the bioavailability of drugs within the body and achieving precision therapy with fewer toxic side effects. Furthermore, the integration of exosomes with tissue engineering and chemical modification strategies can also significantly enhance their efficacy in facilitating tissue repair. However, the current research on ADSC-Exos for improving MSDs remains at an early stage and needs further exploration. Therefore, this review summarized the ADSC-Exo as a nanodrug carrier characteristics and mechanism in the treatment of fracture, osteoporosis, osteoarthritis, intervertebral disc degeneration, and tendon injury, which push forward the research progress of ADSC-Exo therapy for MSDs.

Perspective of 3D culture in medicine: transforming disease research and therapeutic applications

3D cell culture is gaining momentum in medicine due to its ability to mimic real tissues (in vivo) and provide more accurate biological data compared to traditional methods. This review explores the current state of 3D cell culture in medicine and discusses future directions, including the need for standardization and simpler protocols to facilitate wider use in research.

Purpose

3D cell culture develops life sciences by mimicking the natural cellular environment. Cells in 3D cultures grow in three dimensions and interact with a matrix, fostering realistic cell behavior and interactions. This enhanced model offers significant advantages for diverse research areas.

Methods

By mimicking the cellular organization and functionalities found in human tissues, 3D cultures provide superior platforms for studying complex diseases like cancer and neurodegenerative disorders. This enables researchers to gain deeper insights into disease progression and identify promising therapeutic targets with greater accuracy. 3D cultures also play a crucial role in drug discovery by allowing researchers to effectively assess potential drugs' safety and efficacy.

Results

3D cell culture's impact goes beyond disease research. It holds promise for tissue engineering. By replicating the natural tissue environment and providing a scaffold for cell growth, 3D cultures pave the way for regenerating damaged tissues, offering hope for treating burns, organ failure, and musculoskeletal injuries. Additionally, 3D cultures contribute to personalized medicine. Researchers can use patient-derived cells to create personalized disease models and identify the most effective treatment for each individual.

Conclusion

With ongoing advancements in cell imaging techniques, the development of novel biocompatible scaffolds and bioreactor systems, and a deeper understanding of cellular behavior within 3D environments, 3D cell culture technology stands poised to revolutionize various aspects of healthcare and scientific discovery.

Exosomes secreted from human-derived adipose stem cells prevent progression of osteonecrosis of the femoral head

BACKGROUND

Osteonecrosis of the femoral head (ONFH) primarily affects young individuals and is a leading cause of total hip arthroplasty in this population. Joint-preserving regenerative therapies involving core decompression (CD), enhanced with cells, growth factors, and bone substitutes, have been developed but lack extensive validation. Exosomes are emerging as a promising regenerative therapy. Human adipose stem cell (hADSC)-derived exosomes exhibit angiogenic and wound-healing effects on damaged and diseased tissues, suggesting their potential efficacy in treating early-stage ONFH. We aimed to investigate the efficacy of hADSC-derived exosomes based on CD in a medium-sized animal model (rabbit).

METHODS

Exosomes were extracted using the ultrafiltration filter technique from the culture supernatants of two types of hADSCs. Characterization of exosomes was performed through nanoparticle tracking analysis, transmission electron microscopy, and the detection of specific biomarkers (CD9, CD63, and CD81) by western blotting. Eighteen rabbits underwent surgical vascular occlusion and intramuscular corticosteroid injections to induce ONFH. Concurrently, CD treatment with local administration of hADSC-derived exosomes (exosome group) or saline (control group) was performed. Femoral heads were harvested at 4, 8, and 12 weeks postoperatively and evaluated using micro-computed tomography and tissue staining to assess the protective effects on osteonecrosis, angiogenesis, and osteogenesis.

RESULTS

Exosomes had average particle concentrations of 1.8 × 1012 or 1.8 × 109 particles/mL, with particle size distributions averaging 61.2 ± 14.7 or 123.1 ± 46.3 nm, and were confirmed by specific biomarkers. The exosome group exhibited a significant reduction in the severe progression of ONFH to stages 3 or 4 of the modified Ficat and Arlet classification, compared to the control group, which had four cases of stages 3 or 4. The exosome group showed significantly fewer empty lacunae in the subchondral bone area (p < 0.05) and significantly less articular cartilage injury (p < 0.05) compared to the corresponding in the control group. There were no significant differences in the microvessel number, bone trabecular structure, or volume of new bone in the medial region of the CD.

CONCLUSIONS

hADSC-derived exosomes can prevent the progression of ONFH by inhibiting osteonecrosis and cartilage damage. The ultrafiltration filter technique is effective for exosome extraction, indicating that exosomes hold potential as a therapeutic agent for ONFH.

Adipose-Derived Mesenchymal Stem Cells from Arthritis Patients: Differential Modulation of CD4⁺ T Cell Activation and Cytokine Production

BACKGROUND Adipose-derived stem cells (ASCs) from intra-articular adipose tissue of osteoarthritis (OA) and rheumatoid arthritis (RA) patients similarly regulate the proliferation of activated CD4⁺ T lymphocytes and exhibit comparable differentiation potential. This study aimed to assess the impact of ASCs from RA patients on CD4⁺ T cell activation and differentiation into Th17 and T regulatory (Treg) cells. MATERIAL AND METHODS Intra-articular adipose tissue samples were obtained from patients with RA and OA, who underwent knee replacement surgery. ASCs were isolated and cultured either with isolated CD4⁺ cells or with peripheral blood mononuclear cells. After culture, CD4⁺ T cell phenotype was evaluated by flow cytometry, and cytokine concentrations in culture supernatants were analyzed via ELISA. Blocking experiments were conducted to identify the soluble agents responsible for the immunomodulatory effects of ASCs. RESULTS RA- and OA-derived ASCs effectively modulated CD25 and CD69 expression on CD4⁺ cells. RA-derived ASCs failed to induce Tregs, decreased HLA-DR expression, and increased IL-35 production. RA- and OA-derived ASCs reduced TNF and IFN-γ production but increased IL-17 production. The immunomodulatory activities of ASCs were linked to the kynurenine pathway and prostaglandin E2. CONCLUSIONS This study indicates that ASCs modulate the phenotype of CD4⁺ T cells and influence the production of both pro-inflammatory and anti-inflammatory cytokines. However, ASCs from RA patients appear to have impaired immunomodulatory abilities, raising concerns about their therapeutic potential. Further research is needed to enhance our understanding of ASCs biology and their therapeutic utility.

Deciphering influence of donor age on adipose-derived stem cells: in vitro paracrine function and angiogenic potential

BACKGROUND

As fat grafting is commonly used as a filler, Adipose-derived stem/stromal cells (ASC) have been reported to be key player in retention rate. Paracrine and differentiation potential of those cells confer them strong pro-angiogenic capacities. However, a full characterization of the influence of aging on ASC has not been reported yet. Here we've investigated the effect of age on paracrine function, stemness and angiogenic potential of ASC.

METHODS

ASC were extracted from young and old adult donors. We assessed stromal vascular fraction cell populations repartition, ASC stemness potential, capability to differentiate into mesenchymal lineages as well as their secretome. Angiogenic potential was assessed using a sprouting assay, an indirect co-culture of ASC and dermal microvascular endothelial cells (EC). Total vascular sprout length was measured, and co-culture soluble factors were quantified. Pro-angiogenic factors alone or in combination as well as ASC-conditioned medium (CM) were added to EC to assess sprouting induction.

RESULTS

Decrease of endothelial cells yield and percentage is observed in cells extracted from adipose tissue of older patients, whereas ASC percentage increased with age. Clonogenic potential of ASC is stable with age. ASC can differentiate into adipocytes, chondrocytes and osteoblasts, and aging does not alter this potential. Among the 25 analytes quantified, high levels of pro-angiogenic factors were found, but none is significantly modulated with age. ASC induce a significantly longer vascular sprouts compared to fibroblasts, and no difference was found between young and old ASC donors on that parameter. Higher concentrations of FGF-2, G-CSF, HGF and IL-8, and lower concentrations of VEGF-C were quantified in EC/ASC co-cultures compared to EC/fibroblasts co-cultures. EC/ASC from young donors secrete higher levels of VEGF-A compared to old ones. Neither soluble factor nor CM without cells are able to induce organized sprouts, highlighting the requirement of cell communication for sprouting. CM produced by ASC supporting development of long vascular sprouts promote sprouting in co-cultures that establish shorter sprouts.

CONCLUSION

Our results show cells from young and old donors exhibit no difference in all assessed parameters, suggesting all patients could be included in clinical applications. We emphasized the leading role of ASC in angiogenesis, without impairment with age, where secretome is a key but not sufficient actor.

Unveiling the immunogenicity of allogeneic mesenchymal stromal cells: Challenges and strategies for enhanced therapeutic efficacy

Mesenchymal stromal cells (MSCs) exhibit significant potential in the context of cell therapy because of their capacity to perform a range of interconnected functions in damaged tissues, including immune modulation, hematopoietic support, and tissue regeneration. MSCs are hypoimmunogenic because of their diminished expression of major histocompatibility molecules, absence of costimulatory molecules, and presence of coinhibitory molecules. While autologous MSCs reduce the risk of rejection and infection, variability in cell numbers and proliferation limits their potential applications. Conversely, allogeneic MSCs (allo-MSCs) possess broad clinical applications unconstrained by donor physiology. Nonetheless, preclinical and clinical investigations highlight that transplanted allo-MSCs are subject to immune attack from recipients. These cells exhibit anti-inflammatory and proinflammatory phenotypes contingent on the microenvironment. Notably, the proinflammatory phenotype features enhanced immunogenicity and diminished immunosuppression, potentially triggering allogeneic immune reactions that impede long-term clinical efficacy. Consequently, preserving the low immunogenicity of allo-MSCs in vivo and mitigating immune rejection in diverse microenvironments represent crucial challenges for the widespread clinical application of MSCs. In this review, we elucidate the immune regulation of allo-MSCs, specifically focusing on two distinct subgroups, MSC1 and MSC2, that exhibit varying polarization states and immunogenicity. We discuss the factors and underlying mechanisms that induce MSC immunogenicity and polarization, highlighting the crucial role of major histocompatibility complex class I/II molecules in rejection post-transplantation. Additionally, we summarize the immunogenic regulatory targets and applications of allo-MSCs and outline strategies to address challenges in this promising field, aiming to enhance allo-MSC therapeutic efficacy for patients.

Enhancement the antioxidative and immunomodulatory functions of mesenchymal stem cells by tetrandrine

In this study, mesenchymal stem cells (MSCs) were primed with Tetrandrine (TET) having anti-inflammatory and immunomodulatory effects to examine the effects of this molecule on the antioxidative potential of MSCs as well as their modulatory effects on activated peripheral blood mononuclear cells (PBMCs). The viability of primed MSCs was detected using MTT assay and Trypan blue staining. Moreover, flow cytometry technique was applied to evaluate cell cycle distribution and immunophenotype of MSCs. The production of superoxide dismutase 3 (SOD3), malondialdehyde (MDA), kynurenine, TGF-β, and IFN-γ were also measured by spectrophotometry to assess the alteration of antioxidative and immunomodulatory potential of MSCs. Then, TET-primed MSCs were cocultured with PBMCs. The MTT assay was used to measure the proliferation of PBMCs. Cell cycle progression of PBMCs and frequency of regulatory T cells were evaluated using Flow cytometry. ELISA assay was also applied to determine the concentrations of TGF-β and IFN-γ after coculturing. According to our data, TET enhanced the secretion of SOD3 and kynurenine from MSCs, while the production of IFN-γ was reduced. No changes were observed in the viability, proliferation, and immunophenotype of MSCs after priming with TET. Moreover, the proliferation and frequency of PBMCs in the S and G2/M phases of cell cycle reduced after co-culturing with TET-primed MSCs. The concentration of TGF-β was increased in the supernatant of PBMCs, but the level of IFN-γ was reduced. Our data suggested this priming method as a novel strategy for increasing the antioxidative and immunomodulatory activity of MSCs.

Stem cell-based targeted therapy in pancreatic cancer: Current approaches and future prospects

Despite recent improvements in oncology, diagnosis, and therapy, pancreatic cancer remains extremely difficult to cure due to its aggressive growth pattern with early invasion and distant metastases, chemoresistance, and a lack of effective screening modalities for early detection. Here, novel therapeutic approaches for treating pancreatic cancer are urgently needed. Recently, stem cells have drawn a lot of interest as a possible treatment for pancreatic cancer due to their ability to locate tumors. Though research over the last few decades has revealed some very exciting and promising new treatment approaches, the clinical success of these stem-cell based anti-cancer medicines has been quite limited. The most effective stem cell-mediated therapeutic options will only be available with a deeper understanding of the intricate molecular biology underlying pancreatic cancer and the subsequent identification of cancer stem cells as a novel target that promotes the growth of the cancer and resistance to chemotherapy. This review will highlight the stem cell based anti-cancer therapy targeting pancreatic cancer stem cells and different molecular signaling pathways. A particular focus will be on the therapeutic potential of naïve Stem cells, anti-cancer drug loaded stem cells, genetically engineered stem cells and exosomal miRNA released by stem cells in pancreatic cancer treatment. Similarly, the role of nanotechnology in stem cell based anticancer therapy will be further discussed to better implementation of these cell-based cancer therapy.

Cause and consequence of heterogeneity in human mesenchymal stem cells: Challenges in clinical application

Human mesenchymal stem cells (hMSCs) are mesoderm-derived adult stem cells with self-proliferation capacity, pluripotent differentiation potency, and excellent histocompatibility. These advantages make hMSCs a promising tool in clinical application. However, the majority of clinical trials using hMSC therapy for diverse human diseases do not achieve expectations, despite the prospective pre-clinical outcomes in animal models. This is partly attributable to the intrinsic heterogeneity of hMSCs. In this review, the cause of heterogeneity in hMSCs is systematically discussed at multiple levels, including isolation methods, cultural conditions, donor-to-donor variation, tissue sources, intra-tissue subpopulations, etc. Additionally, the effect of hMSCs heterogeneity on the contrary role in tumor progression and immunomodulation is also discussed. The attempts to understand the cellular heterogeneity of hMSCs and its consequences are important in supporting and improving therapeutic strategies for hMSCs.

Fat Grafting and Regenerative Medicine in Burn Care

Regenerative therapies such as fat grafting and Platelet Rich Plasma (PRP) have emerged as new options to tackle burn-related injuries and their long-term sequelae. Fat grafting is able to promote wound healing by regulating the inflammatory response, stimulating angiogenesis, favoring the remodeling of the extracellular matrix, and enhancing scar appearance. PRP can enhance wound healing by accelerating stages including hemostasis and re-epithelization. It can improve scar quality and complement fat grafting procedures. Their cost-effectiveness, minimal invasiveness, and promising results observed in the literature have made these tools as therapeutic candidates. The current evidence on fat grafting and PRP in acute and reconstructive burns is described and discussed in this study.

Cell-Derived Matrix: Production, Decellularization, and Application of Wound Repair

Chronic nonhealing wounds significantly reduce patients' quality of life and are a major burden on healthcare systems. Over the past few decades, tissue engineering materials have emerged as a viable option for wound healing, with cell-derived extracellular matrix (CDM) showing remarkable results. The CDM's compatibility and resemblance to the natural tissue microenvironment confer distinct advantages to tissue-engineered scaffolds in wound repair. This review summarizes the current processes for CDM preparation, various cell decellularization protocols, and common characterization methods. Furthermore, it discusses the applications of CDM in wound healing, including skin defect and wound repair, angiogenesis, and engineered vessels, and offers perspectives on future developments.

Emerging Strategies in Mesenchymal Stem Cell-Based Cardiovascular Therapeutics

Cardiovascular diseases continue to challenge global health, demanding innovative therapeutic solutions. This review delves into the transformative role of mesenchymal stem cells (MSCs) in advancing cardiovascular therapeutics. Beginning with a historical perspective, we trace the development of stem cell research related to cardiovascular diseases, highlighting foundational therapeutic approaches and the evolution of cell-based treatments. Recognizing the inherent challenges of MSC-based cardiovascular therapeutics, which range from understanding the pro-reparative activity of MSCs to tailoring patient-specific treatments, we emphasize the need to refine the pro-regenerative capacity of these cells. Crucially, our focus then shifts to the strategies of the fourth generation of cell-based therapies: leveraging the secretomic prowess of MSCs, particularly the role of extracellular vesicles; integrating biocompatible scaffolds and artificial sheets to amplify MSCs' potential; adopting three-dimensional ex vivo propagation tailored to specific tissue niches; harnessing the promise of genetic modifications for targeted tissue repair; and institutionalizing good manufacturing practice protocols to ensure therapeutic safety and efficacy. We conclude with reflections on these advancements, envisaging a future landscape redefined by MSCs in cardiovascular regeneration. This review offers both a consolidation of our current understanding and a view toward imminent therapeutic horizons.

Hepatocellular carcinoma patients serum modulates the regenerative capacities of adipose mesenchymal stromal cells

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers causing the highest mortality rate worldwide. Treatment options of surgery, radiation, cytotoxic drugs and liver transplantation suffer significant side effects and a high frequency of relapse. Stem cell therapy has been proposed as a new effective therapy, however, controversial reports are emerging on the role of mesenchymal stem cells in cancer. In this work, we aimed to assess the regenerative capacities of adipose mesenchymal stem cells when exposed to serum from HCC patients, by assessing the effect of the sera on modulating the regenerative capacities of h-AMSCs and the cancer properties in HCC cells. This will pave the way for maximizing the efficacy of MSCs in cancer therapy. Our data show that HCC serum-treated hA-MSCs suffered oncogene-induced senescence as shown by their altered morphology and ameliorated proliferation and differentiation. The cells were enlarged with small irregular nuclei, swollen rough endoplasmic reticulum cisternae, and aging lysosomes typified by dark residual bodies. HCC serum-treated Huh-7 cancer cells on the other hand displayed higher tumor aggressiveness as depicted by altered morphology, increased cellular proliferation and migration, and decreased percentage of early and late apoptotic cells. Our findings provide evidence that exposure of hA-MSCs to the serum of HCC patients decreases their regenerative capacities and should be considered when employed as a potential therapy in HCC patients.

The immunogenic profile and immunomodulatory function of mesenchymal stromal / stem cells in the presence of Ptychotis verticillata

Mesenchymal stromal/stem cells (MSCs) are considered to be a promising immunotherapeutic tool due to their easy accessibility, culture expansion possibilities, safety profile, and immunomodulatory properties. Although several studies have demonstrated the therapeutic effects of MSCs, their efficacy needs to be improved while also preserving their safety. It has been suggested that cell homeostasis may be particularly sensitive to plant extracts. The impact of natural compounds on immunity is thus a fascinating and growing field. Ptychotis verticillata and its bioactive molecules, carvacrol and thymol, are potential candidates for improving MSC therapeutic effects. They can be used as immunotherapeutic agents to regulate MSC functions and behavior during immunomodulation. Depending on their concentrations and incubation time, these compounds strengthened the immunomodulatory functions of MSCs while maintaining their immune-evasive profile. Incubating MSCs with carvacrol and thymol does not alter their hypoimmunogenicity, as no induction of the allogeneic immune response was observed. MSCs also showed enhanced abilities to reduce the proliferation of activated T cells. Thus, MSCs are immunologically responsive to bioactive molecules derived from PV. The bioactivity may depend on the whole phyto-complex of the oil. These findings may contribute to the development of safe and efficient immunotherapeutic MSCs by using medicinal plant-derived active molecules.

Factors Defining Human Adipose Stem/Stromal Cell Immunomodulation in Vitro

Human adipose tissue-derived stem/stromal cells (hASCs) are adult multipotent mesenchymal stem/stromal cells with immunomodulatory capacities. Here, we present up-to-date knowledge on the impact of different experimental and donor-related factors on hASC immunoregulatory functions in vitro. The experimental determinants include the immunological status of hASCs relative to target immune cells, contact vs. contactless interaction, and oxygen tension. Factors such as the ratio of hASCs to immune cells, the cellular context, the immune cell activation status, and coculture duration are also discussed. Conditioning of hASCs with different approaches before interaction with immune cells, hASC culture in xenogenic or xenofree culture medium, hASC culture in two-dimension vs. three-dimension with biomaterials, and the hASC passage number are among the experimental parameters that greatly may impact the hASC immunosuppressive potential in vitro, thus, they are also considered. Moreover, the influence of donor-related characteristics such as age, sex, and health status on hASC immunomodulation in vitro is reviewed. By analysis of the literature studies, most of the indicated determinants have been investigated in broad non-standardized ranges, so the results are not univocal. Clear conclusions cannot be drawn for the fine-tuned scenarios of many important factors to set a standard hASC immunopotency assay. Such variability needs to be carefully considered in further standardized research. Importantly, field experts' opinions may help to make it clearer.

Anti-tumorigenic effects of naive and TLR4-primed adipose-derived mesenchymal stem cells on pancreatic ductal adenocarcinoma cells

BACKGROUND

One of the main reasons for the unsuccessful treatment of pancreatic cancer is the intense desmoplastic pancreatic microenvironment. In the literature, the effects of mesenchymal stem cells (MSCs) and their inflammatory phenotypes on cancer cells have been a subject of controversy. Therefore, it is crucial to elucidate the underlying mechanisms of this interaction, especially in the context of pancreatic cancer. We aimed to investigate the effects of naive, TLR4-activated, and TLR4-inhibited phenotypes of adipose-derived MSCs (ADMSC) on pancreatic ductal cell line (Panc-1).

METHODS AND MATERIALS

Adipose-derived MSCs were induced into a proinflammatory phenotype using a 0.5 μg/mL dose of TLR4 agonist, while an anti-inflammatory phenotype was generated in ADMSCs using a 25 μg/mL dose of TLR4 antagonist. We observed that the proliferation of Panc-1 cells was inhibited when naive ADMSCs:Panc-1(10:1) and proinflammatory ADMSCs:Panc-1(10:1) were directly cocultured.

RESULTS

In indirect coculture, both naive and proinflammatory ADMSCs exhibited a significant 10-fold increase in their inhibitory effect on the proliferation and colony forming capacity of Panc-1 cells, with the added benefit of inducing apoptosis. In our study, both naive and proinflammatory ADMSCs were found to regulate the expression of genes associated with metastasis (MMP2, KDR, MMP9, TIMP1, IGF2R, and COL1A1) and EMT (CDH1, VIM, ZEB1, and CLDN1) in Panc-1 cells. Remarkably, both naive and proinflammatory ADMSCs demonstrated antitumor effects on Panc-1 cells. However, it was observed that anti-inflammatory ADMSCs showed tumor-promoting effects instead. Furthermore, we observed a reciprocal influence between ADMSCs and Panc-1 cells on each other's proinflammatory cytokine expressions, suggesting a dynamic interplay within the tumor microenvironment.

CONCLUSIONS

These findings underscore the significance of both the naive state and different inflammatory phenotypes of MSCs in the microenvironment and represent a pivotal step toward the development of novel therapeutic approaches for pancreatic cancer. Understanding the intricate interactions between MSCs and cancer cells may open new avenues for targeted interventions in cancer therapy.

Transplantation of adipose derived stem cells in diabetes mellitus; limitations and achievements

Objectives

Diabetes mellitus (DM) is a complex metabolic disease that results from impaired insulin secreting pancreatic β-cells or insulin resistance. Although available medications help control the disease, patients suffer from its complications. Therefore, finding effective therapeutic approaches to treat DM is a priority. Adipose Derived Stem Cells (ADSCs) based therapy is a promising strategy in various regenerative medicine applications, but its systematic translational use is still somewhat out of reach. This review is aimed at clarifying achievements as well as challenges facing the application of ADSCs for the treatment of DM, with a special focus on the mechanisms involved.

Methods

Literature searches were carried out on "Scopus", "PubMed" and "Google Scholar" up to September 2022 to find relevant articles in the English language for the scope of this review.

Results

Recent evidence showed a significant role of ADSC therapies in DM by ameliorating insulin resistance and hyperglycemia, regulating hepatic glucose metabolism, promoting β cell function and regeneration, and functioning as a gene delivery tool. In addition, ADSCs could improve diabetic wound healing by promoting collagen deposition, inhibiting inflammation, and enhancing angiogenesis.

Conclusion

Overall, this literature review revealed the great clinical implications of ADSCs for translating into the clinical setting for the treatment of diabetes. However, further large-scale and controlled studies are needed to overcome challenges and confirm the safety and optimal therapeutic scheme before daily clinical application.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01280-8.

Stem cells therapy for diabetes: from past to future

Diabetes mellitus is a chronic disease of carbohydrate metabolism characterized by uncontrolled hyperglycemia due to the body's impaired ability to produce or respond to insulin. Oral or injectable exogenous insulin and its analogs cannot mimic endogenous insulin secreted by healthy individuals, and pancreatic and islet transplants face a severe shortage of sources and transplant complications, all of which limit the widespread use of traditional strategies in diabetes treatment. We are now in the era of stem cells and their potential in ameliorating human disease. At the same time, the rapid development of gene editing and cell-encapsulation technologies has added to the wings of stem cell therapy. However, there are still many unanswered questions before stem cell therapy can be applied clinically to patients with diabetes. In this review, we discuss the progress of strategies to obtain insulin-producing cells from different types of stem cells, the application of gene editing in stem cell therapy for diabetes, as well as summarize the current advanced cell encapsulation technologies in diabetes therapy and look forward to the future development of stem cell therapy in diabetes.

Potential Therapeutic Use of Stem Cells for Prion Diseases

Prion diseases are neurodegenerative disorders that are progressive, incurable, and deadly. The prion consists of PrPSc, the misfolded pathogenic isoform of the cellular prion protein (PrPC). PrPC is involved in a variety of physiological functions, including cellular proliferation, adhesion, differentiation, and neural development. Prion protein is expressed on the membrane surface of a variety of stem cells (SCs), where it plays an important role in the pluripotency and self-renewal matrix, as well as in SC differentiation. SCs have been found to multiply the pathogenic form of the prion protein, implying their potential as an in vitro model for prion diseases. Furthermore, due to their capability to self-renew, differentiate, immunomodulate, and regenerate tissue, SCs are prospective cell treatments in many neurodegenerative conditions, including prion diseases. Regenerative medicine has become a new revolution in disease treatment in recent years, particularly with the introduction of SC therapy. Here, we review the data demonstrating prion diseases' biology and molecular mechanism. SC biology, therapeutic potential, and its role in understanding prion disease mechanisms are highlighted. Moreover, we summarize preclinical studies that use SCs in prion diseases.

A vision for safer food contact materials: Public health concerns as drivers for improved testing

Food contact materials (FCMs) and food contact articles are ubiquitous in today's globalized food system. Chemicals migrate from FCMs into foodstuffs, so called food contact chemicals (FCCs), but current regulatory requirements do not sufficiently protect public health from hazardous FCCs because only individual substances used to make FCMs are tested and mostly only for genotoxicity while endocrine disruption and other hazard properties are disregarded. Indeed, FCMs are a known source of a wide range of hazardous chemicals, and they likely contribute to highly prevalent non-communicable diseases. FCMs can also include non-intentionally added substances (NIAS), which often are unknown and therefore not subject to risk assessment. To address these important shortcomings, we outline how the safety of FCMs may be improved by (1) testing the overall migrate, including (unknown) NIAS, of finished food contact articles, and (2) expanding toxicological testing beyond genotoxicity to multiple endpoints associated with non-communicable diseases relevant to human health. To identify mechanistic endpoints for testing, we group chronic health outcomes associated with chemical exposure into Six Clusters of Disease (SCOD) and we propose that finished food contact articles should be tested for their impacts on these SCOD. Research should focus on developing robust, relevant, and sensitive in-vitro assays based on mechanistic information linked to the SCOD, e.g., through Adverse Outcome Pathways (AOPs) or Key Characteristics of Toxicants. Implementing this vision will improve prevention of chronic diseases that are associated with hazardous chemical exposures, including from FCMs.

Co-Administration of Resolvin D1 and Peripheral Nerve-Derived Stem Cell Spheroids as a Therapeutic Strategy in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI), primarily caused by trauma, leads to permanent and lasting loss of motor, sensory, and autonomic functions. Current therapeutic strategies are focused on mitigating secondary injury, a crucial aspect of SCI pathophysiology. Among these strategies, stem cell therapy has shown considerable therapeutic potential. This study builds on our previous work, which demonstrated the functional recovery and neuronal regeneration capabilities of peripheral nerve-derived stem cell (PNSC) spheroids, which are akin to neural crest stem cells, in SCI models. However, the limited anti-inflammatory capacity of PNSC spheroids necessitates a combined therapeutic approach. As a result, we investigated the potential of co-administering resolvin D1 (RvD1), known for its anti-inflammatory and neuroprotective properties, with PNSC spheroids. In vitro analysis confirmed RvD1's anti-inflammatory activity and its inhibitory effect on pro-inflammatory cytokines. In vivo studies involving a rat SCI model demonstrated that combined therapy of RvD1 and PNSC spheroids outperformed monotherapies, exhibiting enhanced neuronal regeneration and anti-inflammatory effects as validated through behavior tests, quantitative reverse transcription polymerase chain reaction, and immunohistochemistry. Thus, our findings suggest that the combined application of RvD1 and PNSC spheroids may represent a novel therapeutic approach for SCI management.

Tailoring the secretome composition of mesenchymal stem cells to augment specific functions of epidermal regeneration: an in vitro diabetic model

Introduction

Wound healing consists of a dynamic series of events that are highly dependent on paracrine factors for proper progression through the phases of wound healing. Inappropriate progression through the phases is associated with insufficient epidermal regeneration (i.e., re-epithelialization) of wounds and subsequent propagation of chronic wounds, such as diabetic ulcers, which are associated with increased patient morbidity. Recently, investigation into the dynamic secretome of Adipose-derived Mesenchymal Stem Cells (ASCs), have shown promise in augmenting the wound healing response of chronic diabetic wounds. However, currently utilized 2D culture techniques are known to drastically alter the regenerative phenotype of ASCs. In this study a novel tissue-mimetic 3D system was utilized as a means to culture ASCs.

Methods

The capacity for the ASC secretome to augment epidermal regeneration activity was then evaluated after exposure of ASCs to "wound priming stimuli" in 2D and 3D. The priming stimuli consisted of coating the 2D and 3D systems with the wound matrix proteins, collagen type I, fibronectin, and fibrin. To understand the potential benefit of the ASC secretome in the context of diabetic wounds, keratinocytes (KCs) were exposed to super-physiological glucose levels to induce a diabetic-like phenotype (idKCs).

Results

Relative to KCs, idKC exhibited a 52% and 23% decline in proliferation and migration, respectively. Subsequently, analyses of the ASC secretome were performed. ASC conditioned media (ASC-CM) from tissue-mimetic culture demonstrated a > 50% increase secretion of proteins and a 2-fold increase in secreted EVs, relative to 2D culture. Interestingly, the different priming stimuli did not alter the total amount of protein or EVs secreted within the tissue-mimetic system. However, evaluation of specific soluble proteins via ELISA revealed significant differences in key epidermal regeneration factors, such as EGF, IGF-1, FGF-2, MMP-1, TIMP-1, and TGFβ-1. Additionally, the relative effect of ASC-EVs from the 2D and 3D system on idKCs epidermal regeneration functionality varied significantly, with EVs from 3D-Collagen culture providing the most significant benefit on idKC activity.

Discussion

Together, these data support the utilization of tissue-mimetic culture system to enhance the adaptability and secretory activity of MSC-like populations in order to generate tailored biologics, via priming stimuli, for specific wound healing applications.

Mesenchymal-Stromal-Cell-Conditioned Media and Their Implication for Osteochondral Regeneration

Despite significant advances in biomedical research, osteochondral defects resulting from injury, an autoimmune condition, cancer, or other pathological conditions still represent a significant medical problem. Even though there are several conservative and surgical treatment approaches, in many cases, they do not bring the expected results and further permanent damage to the cartilage and bones occurs. Recently, cell-based therapies and tissue engineering have gradually become promising alternatives. They combine the use of different types of cells and biomaterials to induce regeneration processes or replace damaged osteochondral tissue. One of the main challenges of this approach before clinical translation is the large-scale in vitro expansion of cells without changing their biological properties, while the use of conditioned media which contains various bioactive molecules appears to be very important. The presented manuscript provides a review of the experiments focused on osteochondral regeneration by using conditioned media. In particular, the effect on angiogenesis, tissue healing, paracrine signaling, and enhancing the properties of advanced materials are pointed out.

Gene Therapy Based on Mesenchymal Stem Cells Derived from Adipose Tissue for the Treatment of Obesity and Its Metabolic Complications

Obesity is a highly prevalent condition often associated with dysfunctional adipose tissue. Stem cell-based therapies have become a promising tool for therapeutic intervention in the context of regenerative medicine. Among all stem cells, adipose-derived mesenchymal stem cells (ADMSCs) are the most easily obtained, have immunomodulatory properties, show great ex vivo expansion capacity and differentiation to other cell types, and release a wide variety of angiogenic factors and bioactive molecules, such as growth factors and adipokines. However, despite the positive results obtained in some pre-clinical studies, the actual clinical efficacy of ADMSCs still remains controversial. Transplanted ADMSCs present a meager rate of survival and proliferation, possibly because of the damaged microenvironment of the affected tissues. Therefore, there is a need for novel approaches to generate more functional ADMSCs with enhanced therapeutic potential. In this context, genetic manipulation has emerged as a promising strategy. In the current review, we aim to summarize several adipose-focused treatments of obesity, including cell therapy and gene therapy. Particular emphasis will be given to the continuum from obesity to metabolic syndrome, diabetes, and underlying non-alcoholic fatty liver disease (NAFLD). Furthermore, we will provide insights into the potential shared adipocentric mechanisms involved in these pathophysiological processes and their remediation using ADMSCs.

Effects of Dental Pulp Stem Cell Preconditioning on Osteogenesis using Conditioned Media of Probiotics Bacteria

Background

Stem cells are used to treat numerous diseases; however, their lifespan is rather short. Factors such as probiotics affect and improve various cell lineage efficacies. The aim of this study was to investigate the effects of probiotics-conditioned media on dental pulp stem cell potentials in osteogenesis.

Methods

The experiment was initiated by culturing Lactobacillus casei and Lactobacillus acidophilus probiotics as well as DPS-7 cells. Bacterial supernatants were separated and concentrated as the conditioned media. The DPS-7 cells were treated with various concentrations of the conditioned media. Furthermore, MTT assay and alkaline phosphatase activity were used. The mRNA expression of three genes (bFGF, EGF-β and BMP-2) involved in osteogenesis was analyzed using a real-time polymerase chain reaction.

Results

The response of dental pulp stem cells to probiotics preconditioning promoted cell proliferation, increased alkaline phosphatase activity and upregulated bFGF and BMP-2 gene expression. Increased expression was significant for BMP-2 and moderate for bFGF; however, it was non-significant for EGF-β. The use of the two probiotics was the most effective.

Conclusion

In general, synergism of the combined probiotics preconditioning induces differentiation of DPS-7 cells into osteoblasts most effectively.

Mitochondrial Metabolism and EV Cargo of Endothelial Cells Is Affected in Presence of EVs Derived from MSCs on Which HIF Is Activated

Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) have attracted growing interest as a possible novel therapeutic agent for the management of different cardiovascular diseases (CVDs). Hypoxia significantly enhances the secretion of angiogenic mediators from MSCs as well as sEVs. The iron-chelating deferoxamine mesylate (DFO) is a stabilizer of hypoxia-inducible factor 1 and consequently used as a substitute for environmental hypoxia. The improved regenerative potential of DFO-treated MSCs has been attributed to the increased release of angiogenic factors, but whether this effect is also mediated by the secreted sEVs has not yet been investigated. In this study, we treated adipose-derived stem cells (ASCs) with a nontoxic dose of DFO to harvest sEVs (DFO-sEVs). Human umbilical vein endothelial cells (HUVECs) treated with DFO-sEVs underwent mRNA sequencing and miRNA profiling of sEV cargo (HUVEC-sEVs). The transcriptomes revealed the upregulation of mitochondrial genes linked to oxidative phosphorylation. Functional enrichment analysis on miRNAs of HUVEC-sEVs showed a connection with the signaling pathways of cell proliferation and angiogenesis. In conclusion, mesenchymal cells treated with DFO release sEVs that induce in the recipient endothelial cells molecular pathways and biological processes strongly linked to proliferation and angiogenesis.

Fat Graft Retention: Adipose Tissue, Adipose-Derived Stem Cells, and Aging

SUMMARY

Over the past 30 years, there has been a dramatic increase in the use of autologous fat grafting for soft-tissue augmentation and to improve facial skin quality. Several studies have highlighted the impact of aging on adipose tissue, leading to a decrease of adipose tissue volume and preadipocyte proliferation and increase of fibrosis. Recently, there has been a rising interest in adipose tissue components, including adipose-derived stem/stromal cells (ASCs) because of their regenerative potential, including inflammation, fibrosis, and vascularization modulation. Because of their differentiation potential and paracrine function, ASCs have been largely used for fat grafting procedures, as they are described to be a key component in fat graft survival. However, many parameters as surgical procedures or adipose tissue biology could change clinical outcomes. Variation on fat grafting methods have led to numerous inconsistent clinical outcomes. Donor-to-donor variation could also be imputed to ASCs, tissue inflammatory state, or tissue origin. In this review, the authors aim to analyze (1) the parameters involved in graft survival, and (2) the effect of aging on adipose tissue components, especially ASCs, that could lead to a decrease of skin regeneration and fat graft retention.

CLINICAL RELEVANCE STATEMENT

This review aims to enlighten surgeons about known parameters that could play a role in fat graft survival. ASCs and their potential mechanism of action in regenerative medicine are more specifically described.

Adipose-Derived Mesenchymal Stromal Cells in Basic Research and Clinical Applications

Adipose-derived mesenchymal stromal cells (AD-MSCs) have been extensively studied in recent years. Their attractiveness is due to the ease of obtaining clinical material (fat tissue, lipoaspirate) and the relatively large number of AD-MSCs present in adipose tissue. In addition, AD-MSCs possess a high regenerative potential and immunomodulatory activities. Therefore, AD-MSCs have great potential in stem cell-based therapies in wound healing as well as in orthopedic, cardiovascular, or autoimmune diseases. There are many ongoing clinical trials on AD-MSC and in many cases their effectiveness has been proven. In this article, we present current knowledge about AD-MSCs based on our experience and other authors. We also demonstrate the application of AD-MSCs in selected pre-clinical models and clinical studies. Adipose-derived stromal cells can also be the pillar of the next generation of stem cells that will be chemically or genetically modified. Despite much research on these cells, there are still important and interesting areas to explore.

Hybrid Stromal Vascular Fraction (Hybrid-SVF): A New Paradigm in Mechanical Regenerative Cell Processing

Enzymatic digestion of extracellular matrix (ECM) from lipoaspirate is the conventional form of harvesting stromal vascular fraction (SVF) called enzymatically digested SVF (E-SVF). Mechanical SVF (M-SVF) isolation has emerged as an alternative method, but it has also some limitations in terms of lower cell viability and diminished cell counts. To enhance the SVF qualitatively and quantitatively, we propose a novel concept called "hybrid-SVF," in which we combine M-SVF with the concentrated parts of adipose tissue after centrifugation, which is called stromal vascular matrix (SVM).

Methods

Hybrid-SVF injection was applied as an adjunctive therapy to fat grafting in 88 patients and 11 samples were evaluated in the laboratory for cell count, viability and cell activity.

Results

Experimental results determined that SVM part showed higher cellular activity. SVM and M-SVF showed higher cellular potency than E-SVF. Clinically, none of the patients required an additional session for fat grafting since there was no significant graft resorption. However, seven patients asked for further volume augmentation due to their individual preferences. No major complication was encountered.

Conclusions

The usage of hybrid-SVF has a very high regenerative potential due to the ECM support and exceptionally high cell yield in addition to preserved cell potency. Although there are ongoing studies focusing on optimizing cell counts and further clinical applications, we believe that our preliminary results might create a paradigm shift in the area of regenerative fat grafting.

Guiding stem cells for cutaneous repair

The significance of mesenchymal stem cells (MSCs) for tissue repair and regeneration is widely recognized. The pleiotropic nature of MSCs is demonstrated by their potential for proliferation and differentiation, and paracrine secretions, thereby making them ideal candidates for cell replacement therapy. Tissue resident MSCs are engaged in homeostasis under normal wear and tear. However, stem cell therapy may be applicable if damage cannot be repaired by normal homeostatic mechanisms. The safety of MSCs has been clearly established in clinical trials but their efficacy remains questionable. The efficacy of MSCs depends on several factors, such as their viability, functional status in terms of secretome secretions, and the in-vivo scenario after transplantation. The performance of MSCs is regulated by their micro-environmental conditions and cues. The so-called MSC niche comprises physical, chemical, and biological components, which play key roles in determining the fate of MSCs. MSCs scaled up for transplantation purposes comprise a disorganized mass of cells, which needs to be directed to perform the required function. Thus, MSCs need to be directed toward an expected target activity in human patients. This review focuses on the various methods that can be used to guide stem cells for cutaneous repair.

Small extracellular vesicles of hypoxic endothelial cells regulate the therapeutic potential of adipose-derived mesenchymal stem cells via miR-486-5p/PTEN in a limb ischemia model

Background

Patients with critical limb ischemia (CLI) are at great risk of major amputation and cardiovascular events. Adipose-derived mesenchymal stem cell (ADSC) therapy is a promising therapeutic strategy for CLI, but the poor engraftment and insufficient angiogenic ability of ADSCs limit their regenerative potential. Herein, we explored the potential of human umbilical vein endothelial cells (HUVECs)-derived small extracellular vesicles (sEVs) for enhancing the therapeutic efficacy of ADSCs in CLI.

Results

sEVs derived from hypoxic HUVECs enhanced the resistance of ADSCs to reactive oxygen species (ROS) and further improved the proangiogenic ability of ADSCs in vitro. We found that the hypoxic environment altered the composition of sEVs from HUVECs and that hypoxia increased the level of miR-486-5p in sEVs. Compared to normoxic sEVs (nsEVs), hypoxic sEVs (hsEVs) of HUVECs significantly downregulated the phosphatase and tensin homolog (PTEN) via direct targeting of miR-486-5p, therefore activating the AKT/MTOR/HIF-1α pathway and influencing the survival and pro-angiogenesis ability of ADSCs. In a hindlimb ischemia model, we discovered that hsEVs-primed ADSCs exhibited superior cell engraftment, and resulted in better angiogenesis and tissue repair.

Conclusion

hsEVs could be used as a therapeutic booster to improve the curative potential of ADSCs in a limb ischemia model. This finding offers new insight for CLI treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01632-1.

Multi-omics analysis of an in vitro photoaging model and protective effect of umbilical cord mesenchymal stem cell-conditioned medium

Background

Skin ageing caused by long-term ultraviolet (UV) irradiation is a complex biological process that involves multiple signalling pathways. Stem cell-conditioned media is believed to have anti-ageing effects on the skin. The purpose of this study was to explore the biological effects of UVB irradiation and anti-photoaging effects of human umbilical cord mesenchymal stem cell-conditioned medium (hUC-MSC-CM) on HaCaT cells using multi-omics analysis with a novel cellular photoaging model.

Methods

A cellular model of photoaging was constructed by irradiating serum-starved HaCaT cells with 20 mJ/cm² UVB. Transcriptomics and proteomics analyses were used to explore the biological effects of UVB irradiation on photoaged HaCaT cells. Changes in cell proliferation, apoptosis, and migration, the cell cycle, and expression of senescence genes and proteins were measured to assess the protective effects of hUC-MSC-CM in the cellular photoaging model.

Results

The results of the multi-omics analysis revealed that UVB irradiation affected various biological functions of cells, including cell proliferation and the cell cycle, and induced a senescence-associated secretory phenotype. hUC-MSC-CM treatment reduced cell apoptosis, inhibited G1 phase arrest in the cell cycle, reduced the production of reactive oxygen species, and promoted cell motility. The qRT-PCR results indicated that MYC, IL-8, FGF-1, and EREG were key genes involved in the anti-photoaging effects of hUC-MSC-CM. The western blotting results demonstrated that C-FOS, C-JUN, TGFβ, p53, FGF-1, and cyclin A2 were key proteins involved in the anti-photoaging effects of hUC-MSC-CM.

Conclusion

Serum-starved HaCaT cells irradiated with 20 mJ/cm² UVB were used to generate an innovative cellular photoaging model, and hUC-MSC-CM demonstrates potential as an anti-photoaging treatment for skin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03137-y.

Impact of Adipose-Derived Mesenchymal Stem Cells (ASCs) of Rheumatic Disease Patients on T Helper Cell Differentiation

Complex pathogenesis of systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) is associated with an imbalance of various Th-cell subpopulations. Mesenchymal stem cells (MSCs) have the ability to restore this balance. However, bone marrow-derived MSCs of SLE and SSc patients exhibit many abnormalities, whereas the properties of adipose derived mesenchymal stem cells (ASCS) are much less known. Therefore, we examined the effect of ASCs obtained from SLE (SLE/ASCs) and SSc (SSc/ASCs) patients on Th subset differentiation, using cells from healthy donors (HD/ASCs) as controls. ASCs were co-cultured with activated CD4⁺ T cells or peripheral blood mononuclear cells. Expression of transcription factors defining Th1, Th2, Th17, and regulatory T cell (Tregs) subsets, i.e., T-bet, GATA3, RORc, and FoxP3, were analysed by quantitative RT-PCR, the concentrations of subset-specific cytokines were measured by ELISA, and Tregs formation by flow cytometry. Compared with HD/ASCs, SLE/ASCs and especially SSc/ASCs triggered Th differentiation which was disturbed at the transcription levels of genes encoding Th1- and Tregs-related transcription factors. However, we failed to find functional consequences of this abnormality, because all tested ASCs similarly switched differentiation from Th1 to Th2 direction with accompanying IFNγ/IL-4 ratio decrease, up-regulated Th17 formation and IL-17 secretion, and up-regulated classical Tregs generation.

Short-Term Autophagy Preconditioning Upregulates the Expression of COX2 and PGE2 and Alters the Immune Phenotype of Human Adipose-Derived Stem Cells In Vitro

Human adipose-derived stem cells (hASCs) are potent modulators of inflammation and promising candidates for the treatment of inflammatory and autoimmune diseases. Strategies to improve hASC survival and immunoregulation are active areas of investigation. Autophagy, a homeostatic and stress-induced degradative pathway, plays a crucial role in hASC paracrine signaling—a primary mechanism of therapeutic action. Therefore, induction of autophagy with rapamycin (Rapa), or inhibition with 3-methyladenine (3-MA), was examined as a preconditioning strategy to enhance therapeutic efficacy. Following preconditioning, both Rapa and 3-MA-treated hASCs demonstrated preservation of stemness, as well as upregulated transcription of cyclooxygenase-2 (COX2) and interleukin-6 (IL-6). Rapa-ASCs further upregulated TNFα-stimulated gene-6 (TSG-6) and interleukin-1 beta (IL-1β), indicating additional enhancement of immunomodulatory potential. Preconditioned cells were then stimulated with the inflammatory cytokine interferon-gamma (IFNγ) and assessed for immunomodulatory factor production. Rapa-pretreated cells, but not 3-MA-pretreated cells, further amplified COX2 and IL-6 transcripts following IFNγ exposure, and both groups upregulated secretion of prostaglandin-E2 (PGE2), the enzymatic product of COX2. These findings suggest that a 4-h Rapa preconditioning strategy may bestow the greatest improvement to hASC expression of cytokines known to promote tissue repair and regeneration and may hold promise for augmenting the therapeutic potential of hASCs for inflammation-driven pathological conditions.

Catching Them Early: Framework Parameters and Progress for Prenatal and Childhood Application of Advanced Therapies

Advanced therapy medicinal products (ATMPs) are medicines for human use based on genes, cells or tissue engineering. After clear successes in adults, the nascent technology now sees increasing pediatric application. For many still untreatable disorders with pre- or perinatal onset, timely intervention is simply indispensable; thus, prenatal and pediatric applications of ATMPs hold great promise for curative treatments. Moreover, for most inherited disorders, early ATMP application may substantially improve efficiency, economy and accessibility compared with application in adults. Vindicating this notion, initial data for cell-based ATMPs show better cell yields, success rates and corrections of disease parameters for younger patients, in addition to reduced overall cell and vector requirements, illustrating that early application may resolve key obstacles to the widespread application of ATMPs for inherited disorders. Here, we provide a selective review of the latest ATMP developments for prenatal, perinatal and pediatric use, with special emphasis on its comparison with ATMPs for adults. Taken together, we provide a perspective on the enormous potential and key framework parameters of clinical prenatal and pediatric ATMP application.

Potential pre-activation strategies for improving therapeutic efficacy of mesenchymal stem cells: current status and future prospects

Mesenchymal stem cell (MSC)-based therapy has been considered as a promising approach targeting a variety of intractable diseases due to remarkable multiple effect of MSCs, such as multilineage differentiation, immunomodulatory property, and pro-regenerative capacity. However, poor engraftment, low survival rate of transplanted MSC, and impaired donor-MSC potency under host age/disease result in unsatisfactory therapeutic outcomes. Enhancement strategies, including genetic manipulation, pre-activation, and modification of culture method, have been investigated to generate highly functional MSC, and approaches for MSC pre-activation are highlighted. In this review, we summarized the current approaches of MSC pre-activation and further classified, analysed the scientific principles and main characteristics of these manipulations, and described the pros and cons of individual pre-activation strategies. We also discuss the specialized tactics to solve the challenges in this promising field so that it improves MSC therapeutic functions to serve patients better.

Therapeutic Mesenchymal Stem/Stromal Cells: Value, Challenges and Optimization

Cellular therapy aims to replace damaged resident cells by restoring cellular and molecular environments suitable for tissue repair and regeneration. Among several candidates, mesenchymal stem/stromal cells (MSCs) represent a critical component of stromal niches known to be involved in tissue homeostasis. In vitro, MSCs appear as fibroblast-like plastic adherent cells regardless of the tissue source. The therapeutic value of MSCs is being explored in several conditions, including immunological, inflammatory and degenerative diseases, as well as cancer. An improved understanding of their origin and function would facilitate their clinical use. The stemness of MSCs is still debated and requires further study. Several terms have been used to designate MSCs, although consensual nomenclature has yet to be determined. The presence of distinct markers may facilitate the identification and isolation of specific subpopulations of MSCs. Regarding their therapeutic properties, the mechanisms underlying their immune and trophic effects imply the secretion of various mediators rather than direct cellular contact. These mediators can be packaged in extracellular vesicles, thus paving the way to exploit therapeutic cell-free products derived from MSCs. Of importance, the function of MSCs and their secretome are significantly sensitive to their environment. Several features, such as culture conditions, delivery method, therapeutic dose and the immunobiology of MSCs, may influence their clinical outcomes. In this review, we will summarize recent findings related to MSC properties. We will also discuss the main preclinical and clinical challenges that may influence the therapeutic value of MSCs and discuss some optimization strategies.

Impact and Possible Mechanism(s) of Adipose Tissue-Derived Mesenchymal Stem Cells on T-Cell Proliferation in Patients With Rheumatic Disease

Objectives: Systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) are chronic wasting, incurable rheumatic diseases of autoimmune background, in which T cells play a critical pathogenic role. Autologous adipose tissue-derived mesenchymal stem cells (ASCs) may represent an alternative therapeutic option for SLE and SSc patients, but the biology of these cells is poorly understood. Methods: Herein, we evaluated the anti-proliferative impact of ASCs of healthy donors (HD/ASCs, 5 reference cell lines), SLE patients (n = 20), and SSc patients (n = 20) on T lymphocytes. To assess the direct and indirect pathway of ASCs action, peripheral blood mononuclear cells (PBMCs) and purified CD4+ T cells of HD were activated and co-cultured in cell-to-cell contact (C-C) and transwell (T-W) conditions with untreated or cytokine (TNF + IFNΥ, TI)-licensed ASCs, then analyzed by flow cytometry to rate the proliferation response of CD8+ and/or CD4+ T cells. The concentrations of kynurenines, prostaglandin E2 (PGE2), interleukin 10 (IL-10), and transforming growth factor β (TGFβ) were measured from culture supernatants. Specific inhibitors of these factors (1-MT, indomethacin, and cytokine-neutralizing antibody) were used to assess their contribution to anti-proliferative ASCs action. Results: All tested ASCs significantly decreased the number of proliferating CD4+ and CD8+ T cells, the number of division/proliferating cell (PI), and fold expansion (RI), and similarly upregulated kynurenines and PGE2, but not cytokine levels, in the co-cultures with both types of target cells. However, TI-treated SLE/ASCs and SSc/ASCs exerted a slightly weaker inhibitory effect on CD4+ T-cell replication than their respective HD/ASCs. All ASCs acted mainly via soluble factors. Their anti-proliferative effect was stronger, and kynurenine levels were higher in the T-W condition than the C-C condition. Blocking experiments indicated an involvement of kynurenine pathway in inhibiting the number of proliferating cells, PI, and RI values as well as PGE2 role in decreasing the number of proliferating cells. TGFβ did not contribute to ASCs anti-proliferative capabilities, while IL-10 seems to be involved in such activity of only SLE/ASCs. Conclusion: The results indicate that SLE/ASCs and SSc/ASCs retain their capability to restrain the expansion of allogeneic CD4+ and CD8+ T cells and act by similar mechanisms as ASCs of healthy donors and thus may have therapeutic value.

Secretome effect of adipose tissue-derived stem cells cultured two-dimensionally and three-dimensionally in mice with streptozocin induced type 1 diabetes

Aims

To analyze therapeutic potential of the conditioned medium from adipose tissue-derived stem cells (ASC) cultivated in 2D (CM-2D) and 3D (CM-3D) models, in mice with Type 1 diabetes (T1D) induced by streptozotocin.

Main methods

Viability andCD105 expression of 2D and 3D ASC were analyzed by flow cytometry. T1D was induced in mice by multiple injections of streptozocin. On the 28th and 29th days after the first injection of streptozocin, diabetic animals received CM-2D or CM-3D. Pancreatic, CM-2D, and CM-3D cytokines were analyzed by cytometric bead array (CBA) and insulin and PDX-1 were observed and quantified by immunohistochemistry. Apoptosis-related proteins were quantified by Western Blotting.

Key findings

ASC in three-dimensional culture released increased levels of IL-6 and IL-2, while IL-4 was decreased. CM-2D induced pancreatic PDX-1 expression and was able to reduce glycemia in diabetic mice one week after injections but not CM-3D. On the other hand, CM-2D and CM-3D were not able to reverse apoptosis of pancreatic cells in diabetic mice nor to increase insulin expression.

Significance

Together, these results demonstrate that the 3D cell culture secretome was not able to improve diabetes type 1 symptoms at the times observed, while 2D cell secretome improved glycemic levels in T1D mice.

Adipose-derived stem cell-derived extracellular vesicles inhibit neuroblastoma growth by regulating GABBR1 activity through LINC00622-mediated transcription factor AR

Neuroblastoma (NB) is a huge threat to children's health. Adipose-derived stem cells-derived extracellular vesicles (ADSC-Evs) can regulate tumor progression. This study aimed to identify the role of ADSC-Evs in NB. Following ADSC-Ev isolation and identification, PKH26-labeled ADSC-Evs were cocultured with NB cells to observe the internalization of ADSC-Evs. ADSC-Ev effects on NB cell proliferation, invasion, and migration were assessed. The regulatory molecules related to NB development were predicted. The expressions of and relations among LINC00622, transcriptional factor androgen receptor (AR), and gamma-aminobutyric acid B-type receptor 1 (GABRR1) were detected and verified. LINC00622 was inhibited in ADSCs to evaluate ADSC-Ev effects on NB cells. Xenograft tumor experiment in nude mice was further performed to evaluate the effects of ADSC-Evs-carried LINC00622 on NB in vivo. ADSC-Evs inhibited NB cell proliferation, invasion, and migration. ADSC-Evs increased GABBR1 expression in NB cells. ADSC-Evs-carried LINC00622 mediated AR to promote GABBR1 expression. Silencing LINC00622 in ADSCs weakened the inhibition of ADSC-Evs on NB cell malignant behaviors. ADSC-Evs reduced tumor growth in nude mice, which was restored after inhibiting LINC00622 expression in ADSCs. We highlighted that ADSC-Evs carried LINC00622 into NB cells to inhibit transcription factor AR and promote GABBR1 expression, thus inhibiting NB cell growth.

Strategies to improve regenerative potential of mesenchymal stem cells

In the last few decades, stem cell-based therapies have gained attention worldwide for various diseases and disorders. Adult stem cells, particularly mesenchymal stem cells (MSCs), are preferred due to their significant regenerative potential in cellular therapies and are currently involved in hundreds of clinical trials. Although MSCs have high self-renewal as well as differentiation potential, such abilities are compromised with "advanced age" and "disease status" of the donor. Similarly, cell-based therapies require high cell number for clinical applications that often require in vitro expansion of cells. It is pertinent to note that aged individuals are the main segment of population for stem cell-based therapies, however; autologous use of stem cells for such patients (aged and diseased) does not seem to give optimal results due to their compromised potential. In vitro expansion to obtain large numbers of cells also negatively affects the regenerative potential of MSCs. It is therefore essential to improve the regenerative potential of stem cells compromised due to "in vitro expansion", "donor age" and "donor disease status" for their successful autologous use. The current review has been organized to address the age and disease depleted function of resident adult stem cells, and the strategies to improve their potential. To combat the problem of decline in the regenerative potential of cells, this review focuses on the strategies that manipulate the cell environment such as hypoxia, heat shock, caloric restriction and preconditioning with different factors.

Targeting Programmed Cell Death to Improve Stem Cell Therapy: Implications for Treating Diabetes and Diabetes-Related Diseases

Stem cell therapies have shown promising therapeutic effects in restoring damaged tissue and promoting functional repair in a wide range of human diseases. Generations of insulin-producing cells and pancreatic progenitors from stem cells are potential therapeutic methods for treating diabetes and diabetes-related diseases. However, accumulated evidence has demonstrated that multiple types of programmed cell death (PCD) existed in stem cells post-transplantation and compromise their therapeutic efficiency, including apoptosis, autophagy, necroptosis, pyroptosis, and ferroptosis. Understanding the molecular mechanisms in PCD during stem cell transplantation and targeting cell death signaling pathways are vital to successful stem cell therapies. In this review, we highlight the research advances in PCD mechanisms that guide the development of multiple strategies to prevent the loss of stem cells and discuss promising implications for improving stem cell therapy in diabetes and diabetes-related diseases.

The immunomodulatory potential of murine adipose-derived mesenchymal stem cells is enhanced following culture on chitosan film

INTRODUCTION

Recent studies show that the paracrine immunomodulatory effects of mesenchymal stem cells (MSCs) are mediated by the secretion of interleukin-10 (IL-10), transforming growth factor-beta (TGF β), and nitric oxide (NO). The preconditioning of MSCs improves their immunomodulatory characteristics. Chitosan is a biopolymer with low toxicity and biodegradability, used as a membrane for MSCs three-dimensional culture. The present study aimed to evaluate the levels of immunomodulatory mediators of mesenchymal cells cultured on the chitosan film.

MATERIALS & METHODS

MSCs were isolated from abdominal adipose tissue of BALB/c mice. Flow cytometry and differential culture medium were used to confirm the identity of isolated mesenchymal stem cells. The MSCs were divided into three groups; The first group was treated with 10 ng/mL LPS. The second group was seeded in the flasks coated with the chitosan film (3% w/v). The last group was cultured in the flasks without any preconditioning. After 72 h, IL-10, TGF-β, and NO concentrations were measured in the conditioned media. In addition, the arginase activity in mesenchymal stem cells was measured using a colorimetric method.

RESULTS

The proliferative spindle-shaped MSCs formed several three-dimensional spheroids on the chitosan film. It was shown that the level of TGF-β and IL-10 were increased significantly after treatment with LPS (P = 0.02) and spheroid formation (P = 0.01). In addition, the arginase activity was enormously augmented in spheroids compared to controls (7.13-fold increase; 1.71 ± 0.08 and 0.24 ± 0.01 respectively; P = 0.021). On the other hand, the LPS treatment but not the culture on chitosan film increased the NO level significantly (P = 0.02 and P = 0.14, respectively).

CONCLUSION

Using chitosan film as a three-dimensional culture strategy significantly affects the production of immunosuppressive factors by MSCs in vitro through increased secretion of TGF-β and IL-10 and arginase activity.