Immunomodulatory effect of human adipose tissue-derived adult stem cells: comparison with bone marrow mesenchymal stem cells

Adipose tissue-derived mesenchymal stem cells promote the vascularization of pancreatic islets transplanted into decellularized pancreatic skeletons

We have recently developed a model of pancreatic islet transplantation into a decellularized pancreatic tail in rats. As the pancreatic skeletons completely lack endothelial cells, we investigated the effect of co-transplantation of mesenchymal stem cells and endothelial cells to promote revascularization. Decellularized matrix of the pancreatic tail was prepared by perfusion with Triton X-100, sodium dodecyl sulfate and DNase solution. Isolated pancreatic islets were infused into the skeletons via the splenic vein either alone, together with adipose tissue-derived mesenchymal stem cells (adMSCs), or with a combination of adMSCs and rat endothelial cells (rat ECs). Repopulated skeletons were transplanted into the subcutaneous tissue and explanted 9 days later for histological examination. Possible immunomodulatory effects of rat adMSCs on the survival of highly immunogenic green protein-expressing human ECs were also tested after their transplantation beneath the renal capsule. The immunomodulatory effects of adMSCs were also tested in vitro using the Invitrogen Click-iT EdU system. In the presence of adMSCs, the proliferation of splenocytes as a response to phytohaemagglutinin A was reduced by 47% (the stimulation index decreased from 1.7 to 0.9, P = 0.008) and the reaction to human ECs was reduced by 58% (the stimulation index decreased from 1.6 to 0.7, P = 0.03). Histological examination of the explanted skeletons seeded only with the islets showed their partial disintegration and only a rare presence of CD31-positive cells. However, skeletons seeded with a combination of islets and adMSCs showed preserved islet morphology and rich vascularity. In contrast, the addition of syngeneic rat ECs resulted in islet-cell necrosis with only few endothelial cells present. Live green fluorescence-positive endothelial cells transplanted either alone or with adMSCs were not detected beneath the renal capsule. Though the adMSCs significantly reduced in vitro proliferation stimulated by either phytohaemagglutinin A or by xenogeneic human ECs, in vivo co-transplanted adMSCs did not suppress the post-transplant immune response to xenogeneic ECs. Even in the syngeneic model, ECs co-transplantation did not lead to sufficient vascularization in the transplant area. In contrast, islet co-transplantation together with adMSCs successfully promoted the revascularization of extracellular matrix in the subcutaneous tissue.

[Prerequisite and organisation of health-care pathways for Cell and Gene therapies, using Mesenchymal Stromal Cells (MSC) or Chimeric Antigen Receptor (CAR) T cells, in patients with autoimmune systemic diseases]

First-line treatments of autoimmune systemic diseases (ARD) are based on the use of various types of immunosuppressive or immunomodulatory drugs, either alone or in association, according to standardized reference protocols. Prolonged use of these drugs in severe or refractory ARD is associated with high morbidity and increased mortality. Innovative cell therapies represent a new promising approach for patients with ARDs, with the recent clinical use of: a) mesenchymal stromal cells (MSCs), based on their immunomodulatory, antifibrotic and pro-angiogenic properties and b) Chimeric Antigen Receptors (CAR) T cell therapies T lymphocytes, where genetically modified expression of a chimeric antigen receptor (CAR-T cells). Therapeutic use of MSC or CAR-T cells, remains indications of exception in patients with severe ARDs resistant to prior standard therapies with new prerequisite and organisation of health-care pathways as compared to traditional drugs, not only for the Cell and Gene Therapy (CGT) product definition and delivery process, but also for the patient clinical management before and after administration of the CGT product. The aim of this workshop under the auspices of the French Speaking Society of Bone Marrow and Cell transplantation (SFGM-TC) working group on autoimmune diseases (MATHEC) is to describe: a) the prerequisite for French hospitals to set-up the specific health-care pathways for MSC or CART therapy in ARDs patients, in accordance with regulatory and safety needs to perform academic or industry sponsored clinical trials, and b) the care-pathway for ARD patients treated with CGT, highlighting the importance of working in tandem between the ARD and the CAR-T cell specialist all along the indication, procedures and follow-up of ARDs. Patient safety considerations are central to guidance on patient selection to be validated collectively at the multidisciplinary team meeting (MDTM) based on recent (less than 3 months) thorough patient evaluation. MSC and CAR-T procedural aspects and follow-up are then carried out within appropriately experienced and SFGM-TC accredited centres in close collaboration with the ADs specialist.

Optimizing Cardiomyocyte Differentiation: Comparative Analysis of Bone Marrow and Adipose-Derived Mesenchymal Stem Cells in Rats Using 5-Azacytidine and Low-Dose FGF and IGF Treatment

Mesenchymal stem cells (MSCs) exhibit multipotency, self-renewal, and immune-modulatory properties, making them promising in regenerative medicine, particularly in cardiovascular treatments. However, optimizing the MSC source and induction method of cardiac differentiation is challenging. This study compares the cardiomyogenic potential of bone marrow (BM)-MSCs and adipose-derived (AD)-MSCs using 5-Azacytidine (5-Aza) alone or combined with low doses of Fibroblast Growth Factor (FGF) and Insulin-like Growth Factor (IGF). BM-MSCs and AD-MSCs were differentiated using two protocols: 10 μmol 5-Aza alone and 10 μmol 5-Aza with 1 ng/mL FGF and 10 ng/mL IGF. Morphological, transcriptional, and translational analyses, along with cell viability assessments, were performed. Both the MSC types exhibited similar morphological changes; however, AD-MSCs achieved 70-80% confluence faster than BM-MSCs. Surface marker profiling confirmed CD29 and CD90 positivity and CD45 negativity. The differentiation protocols led to cell flattening and myotube formation, with earlier differentiation in AD-MSCs. The combined protocol reduced cell mortality in BM-MSCs and enhanced the expression of cardiac markers (MEF2c, Troponin I, GSK-3β), particularly in BM-MSCs. Immunofluorescence confirmed cardiac-specific protein expression in all the treated groups. Both MSC types exhibited the expression of cardiac-specific markers indicative of cardiomyogenic differentiation, with the combined treatment showing superior efficiency for BM-MSCs.

Adipose-derived mesenchymal stem cell therapy for connective tissue diseases and complications

Mesenchymal stem cells (MSCs) may be effective in treating connective tissue disease and associated organ damage, leveraging their anti-inflammatory and immunoregulatory effects. Moreover, MSCs may possess the ability to produce antiapoptotic, proliferative, growth, angiogenic, and antifibrotic factors. Among MSCs, adipose-derived MSCs (ASCs) stand out for their relative ease of harvesting and abundance. Additionally, studies have indicated that compared with bone marrow-derived MSCs, ASCs have superior immunomodulatory, proangiogenic, antiapoptotic, and antioxidative properties. However, relatively few reviews have focused on the efficacy of ASC therapy in treating connective tissue disease (CTD) and interstitial lung disease (ILD). Therefore, this review aims to evaluate evidence from preclinical studies that investigate the effectiveness of MSC therapy, specifically ASC therapy, in managing CTD and ILD. Moreover, we explore the outcomes of documented clinical trials. We also introduce an innovative approach involving the utilization of pharmacologically primed ASCs in the CTD model to address the current challenges associated with ASC therapy.

Efficacy of buccal pad fat as a new approach in the treatment of gingival recession: a systematic review

OBJECTIVE

This systematic review evaluates the efficacy of buccal pad fat (BPF) as an autologous graft in the treatment of gingival recession (GR). Thus, the research question explores if the BPF can serve as a viable alternative to the gold standard connective tissue graft.

MATERIALS AND METHODS

Only seven studies met the inclusion criteria were critically appraised including the randomized controlled clinical trials, and case series. The inclusion criteria were systemically healthy individuals in the age range (18-65 years old) with Miller's classification of GR either class I, II, III, or IV while exclusion criteria were patients with poor oral hygiene, pregnant and lactating patients, teeth with caries, any prior surgery in the relevant regions, and use of medications.

RESULTS

The review included 117 patients with 136 GR defects. The age of participants ranges from 20 to 65 years old with the higher percentage of root coverage (%RC) at 6 months in the pedicled BPF group which was 89.30%while the lowest (%RC) at 6 months in the same group was 46.78%. The BPF group's width of keratinized gingiva (WKG) values indicate a notable improvement, suggesting a positive impact on WKG compared to the control group.

CONCLUSIONS

BPF can be considered as a promising graft to augment gingival tissues at different sites in the oral cavity with different Miller's classes of GR providing a new era in GR treatment.

Effectiveness and Safety of Different Methods of Assisted Fat Grafting: A Network Meta-Analysis

OBJECTIVE

Numerous studies have proposed the utilization of stromal vascular fraction (SVF), adipose-derived stem cells (ADSCs), and platelet products as auxiliary grafting techniques to improve the survival rate of fat grafts. This study aimed to evaluate the efficacy and safety of various fat grafting methods since 2010 through a network meta-analysis, aiming to identify the most effective technique for fat grafting.

METHODS

Clinic trials on assisted fat grafting were searched from Pubmed, Embase, Web of Science, and the Cochrane Library, spanning the period from January 1, 2010 to March 2024. The risk of bias in the included trials was meticulously assessed using the Cochrane risk of bias tool. The survival rate of fat grafts served as the primary evaluation metric for effectiveness, while complications were employed as the indicator for safety.

RESULTS

The study incorporated 31 clinic trials, involving a total of 1656 patients. The findings indicated that the survival rate with assisted fat grafting significantly surpassed that of simple fat grafting (SUCRA, 10.43%). Notably, ADSC-assisted fat grafting exhibited the highest survival rate (SUCRA, 82.17%), followed by Salvia miltiorrhiza (SM)-assisted fat grafting (SUCRA, 69.76%). In terms of safety, the most prevalent complications associated with fat grafting were fat sclerosis and fat necrosis. Adc-assisted fat grafting was correlated with the lowest incidence of complications (SUCRA, 41.00%), followed by simple fat grafting (SUCRA, 40.99%). However, PRP-assisted (SUCRA, 52.86%) and SVF-assisted fat grafting (SUCRA, 65.14%) showed higher complication rates.

CONCLUSION

Various methods of assisted fat grafting can significantly enhance the survival rate, but they often fail to effectively mitigate the incidence of complications. Compared to other methods, adipose mesenchymal stem cells-assisted fat grafting consistently yielded a higher survival rate of grafts and fewer complications. Consequently, this approach represents a relatively effective method for assisting in fat grafting at present.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Adipose stem cells drive T cell infiltration in obesity

Obesity is often associated with adipose tissue (AT) inflammation and immune cell infiltration. Writing recently in Cell Reports, Liao et al. investigated the mechanisms of T cell infiltration of AT using single cell (sc)RNA-sequencing (RNA-seq), transplantation studies, in vitro co-cultures, and knock-out mice. They highlighted the crucial role of C-C motif chemokine ligand 5 (CCL5)-secreting adipose stem cells (ASCs), offering insights for potential therapies.

Bioengineered Mesenchymal Stem/Stromal Cells in Anti-Cancer Therapy: Current Trends and Future Prospects

Mesenchymal stem/stromal cells (MSCs) are one of the most widely used cell types in advanced therapies due to their therapeutic potential in the regulation of tissue repair and homeostasis, and immune modulation. However, their use in cancer therapy is controversial: they can inhibit cancer cell proliferation, but also potentially promote tumour growth by supporting angiogenesis, modulation of the immune milieu and increasing cancer stem cell invasiveness. This opposite behaviour highlights the need for careful and nuanced use of MSCs in cancer treatment. To optimize their anti-cancer effects, diverse strategies have bioengineered MSCs to enhance their tumour targeting and therapeutic properties or to deliver anti-cancer drugs. In this review, we highlight the advanced uses of MSCs in cancer therapy, particularly as carriers of targeted treatments due to their natural tumour-homing capabilities. We also discuss the potential of MSC-derived extracellular vesicles to improve the efficiency of drug or molecule delivery to cancer cells. Ongoing clinical trials are evaluating the therapeutic potential of these cells and setting the stage for future advances in MSC-based cancer treatment. It is critical to identify the broad and potent applications of bioengineered MSCs in solid tumour targeting and anti-cancer agent delivery to position them as effective therapeutics in the evolving field of cancer therapy.

Application of Stem Cells Shows Antiinflammatory Effect in an Irradiated Random Pattern Flap Model

BACKGROUND

In reconstructive surgery, local flaps might develop tissue necrosis or partial flap loss especially after previous irradiation, which may be necessary in many tumor entities. The application of stem cells seems promising to improve flap perfusion and might be a possible solution to optimize flap survival.

METHODS

Twenty rats received harvesting of bilateral random pattern fasciocutaneous flaps. The right flaps received 20 Gy ionizing radiation 4 weeks prior to the surgery, while the left flaps served as the non-irradiated control. After flap harvest, four different stem cell mixtures (5 × 106 ASC, ASC-HUVEC, MSC, MSC-HUVEC) were applied under both right and left flaps using 1 mL fibrin glue as the delivery vehicle. Flap size and its necrotic area were examined clinically. Two weeks after the surgery, HE staining and immunohistochemical staining for CD68 and ERG, as well as PCR analysis (Interleukin 6, HIF-1α and VEGF), were performed.

RESULTS

Application of ASCs, ASCs-HUVECs and MSCs resulted in a lower number of CD68-stained cells compared to the no cell group. The expression of Hif1α was higher in the ASC group compared to those in the MSC and previously treated no cell groups. Treatment with MSCs and MSCs-HUVECs prevented shrinking of the flaps in this series.

CONCLUSION

Application of ASCs, MSCs and ASCs-HUVECs was shown to have an antiinflammatory effect. Treatment with MSCs and MSCs-HUVECs can prevent early shrinking of the flaps.

Cornea-Specific Human Adipose Stem Cell-Derived Extracellular Matrix for Corneal Stroma Tissue Engineering

Utilizing tissue-specific extracellular matrices (ECMs) is vital for replicating the composition of native tissues and developing biologically relevant biomaterials. Human- or animal-derived donor tissues and organs are the current gold standard for the source of these ECMs. To overcome the several limitations related to these ECM sources, including the highly limited availability of donor tissues, cell-derived ECM offers an alternative approach for engineering tissue-specific biomaterials, such as bioinks for three-dimensional (3D) bioprinting. 3D bioprinting is a state-of-the-art biofabrication technology that addresses the global need for donor tissues and organs. In fact, there is a vast global demand for human donor corneas that are used for treating corneal blindness, often resulting from damage in the corneal stromal microstructure. Human adipose tissue is one of the most abundant tissues and easy to access, and adipose tissue-derived stem cells (hASCs) are a highly advantageous cell type for tissue engineering. Furthermore, hASCs have already been studied in clinical trials for treating corneal stromal pathologies. In this study, a corneal stroma-specific ECM was engineered without the need for donor corneas by differentiating hASCs toward corneal stromal keratocytes (hASC-CSKs). Furthermore, this ECM was utilized as a component for corneal stroma-specific bioink where hASC-CSKs were printed to produce corneal stroma structures. This cost-effective approach combined with a clinically relevant cell type provides valuable information on developing more sustainable tissue-specific solutions and advances the field of corneal tissue engineering.

Long-Term Effects of Adipose-Derived Stem Cells for the Treatment of Bilateral Limbal Stem Cell Deficiency

PURPOSE

To determine the safety and feasibility of human autologous adipose tissue-derived adult mesenchymal stem cells (ASCs) for ocular surface regeneration in patients with bilateral limbal stem-cell deficiency (LSCD).

METHODS

A phase IIa clinical trial was designed (https://Clinicaltrials.gov, NCT01808378) with 8 patients, 3 of whom had aniridia, 2 meibomian glands diseases, 2 multiple surgeries and 1 chronic chemical injury. The therapeutic protocol was as follows: 6-mm of central corneal epithelium was removed, 400,000 ASCs were injected into each limboconjunctival quadrant, 400,000 ASCs were suspended over the cornea for 20 min, and finally the cornea was covered with an amniotic membrane patch.

RESULTS

No adverse events were detected after a mean of 86,5 months of follow-up. One year after surgery, 6 of the 8 transplants were scored as successful, five patients had improved uncorrected visual acuity (mean of 12 letters), two patients presented epithelial defects (also present at baseline) and the mean percentage of corneal neovascularization was of 28.75% (36.98%, at baseline). Re-examination 24 months after treatment disclosed preserved efficacy in 4 patients. At the last visit (after a mean of 86,5 months of follow up) epithelial defects were absent in all patients although improvement in all of the variables was only maintained in patient 3 (meibomian glands agenesia).

CONCLUSION

ASCs are a feasible and conservative therapy for treating bilateral LSCD. The therapeutic effect differs between etiologies and diminishes over time.

Extracellular vesicles are key players in mesenchymal stem cells' dual potential to regenerate and modulate the immune system

MSCs are used for treatment of inflammatory conditions or for regenerative purposes. MSCs are complete cells and allogenic transplantation is in principle possible, but mostly autologous use is preferred. In recent years, it was discovered that cells secrete extracellular vesicles. These are active budded off vesicles that carry a cargo. The cargo can be miRNA, protein, lipids etc. The extracellular vesicles can be transported through the body and fuse with target cells. Thereby, they influence the phenotype and modulate the disease. The extracellular vesicles have, like the MSCs, immunomodulatory or regenerative capacities. This review will focus on those features of extracellular vesicles and discuss their dual role. Besides the immunomodulation, the regeneration will concentrate on bone, cartilage, tendon, vessels and nerves. Current clinical trials with extracellular vesicles for immunomodulation and regeneration that started in the last five years are highlighted as well. In summary, extracellular vesicles have a great potential as disease modulating entity and treatment. Their dual characteristics need to be taken into account and often are both important for having the best effect.

Mesenchymal stromal cells for improvement of cardiac function following acute myocardial infarction: a matter of timing

Acute myocardial infarction (AMI) is the leading cause of cardiovascular death and remains the most common cause of heart failure. Reopening of the occluded artery, i.e., reperfusion, is the only way to save the myocardium. However, the expected benefits of reducing infarct size are disappointing due to the reperfusion paradox, which also induces specific cell death. These ischemia-reperfusion (I/R) lesions can account for up to 50% of final infarct size, a major determinant for both mortality and the risk of heart failure (morbidity). In this review, we provide a detailed description of the cell death and inflammation mechanisms as features of I/R injury and cardioprotective strategies such as ischemic postconditioning as well as their underlying mechanisms. Due to their biological properties, the use of mesenchymal stromal/stem cells (MSCs) has been considered a potential therapeutic approach in AMI. Despite promising results and evidence of safety in preclinical studies using MSCs, the effects reported in clinical trials are not conclusive and even inconsistent. These discrepancies were attributed to many parameters such as donor age, in vitro culture, and storage time as well as injection time window after AMI, which alter MSC therapeutic properties. In the context of AMI, future directions will be to generate MSCs with enhanced properties to limit cell death in myocardial tissue and thereby reduce infarct size and improve the healing phase to increase postinfarct myocardial performance.

Molecular mechanism underlying miR-204-5p regulation of adipose-derived stem cells differentiation into cells from three germ layers

The limited differentiation ability of adipose-derived stem cells (ADSCs) limits their application in stem cell therapy and regenerative medicine. Here, we explore the molecular mechanism by which miR-204-5p regulates ADSCs differentiation into cells derived from the three germ layers (i.e., adipocytes, neurocytes, and hepatocytes). Although miR-204-5p overexpression inhibited ADSCs differentiation into adipocytes, neurocyte and hepatocyte differentiation were promoted. Mechanistically, miR-204-5p inhibited the expression of PPARG by regulating the AMPK signaling pathway, thereby inhibiting ADSCs differentiation into adipocytes. Further, miR-204-5p regulated JAG1/NOTCH3 axis for the inhibition of differentiation into adipocytes and promotion of differentiation into neurocytes. miR-204-5p might also promote ADSCs differentiation into hepatocytes by upregulating E2F8. The findings of this study provide novel insights into the regulatory mechanisms underlying early embryonic development and will help to facilitate the application of ADSCs in stem cell therapy and regenerative medicine.

Comparative transcriptomic analysis of bovine mesenchymal stromal cells reveals tissue-source and species-specific differences

Mesenchymal stromal cells (MSCs) have the potential to be used as therapeutics, but their efficacy varies due to cellular heterogeneity, which is not fully understood. After characterizing donor-matched bovine MSC from adipose tissue (AT), bone marrow (BM), and peripheral blood (PB), we performed single-cell RNA sequencing (scRNA-seq) to evaluate overarching similarities and differences across these three tissue-derived MSCs. Next, the transcriptomic profiles of the bovine MSCs were compared to those of equine MSCs, derived from the same tissue sources and previously published by our group, and revealed species-specific differences. Finally, the transcriptomic profile from bovine BM-MSCs was compared to mouse and human BM-MSCs and demonstrated that bovine BM-MSCs share more common functionally relevant gene expression profiles with human BM-MSCs than compared to murine BM-MSCs. Collectively, this study presents the cow as a potential non-traditional animal model for translational MSC studies based on transcriptomic profiles similar to human MSCs.

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.

Alteration of PBMC transcriptome profile after interaction with multipotent mesenchymal stromal cells under "physiological" hypoxia

Multipotent mesenchymal stromal cells (MSCs) have demonstrated a pronounced immunosuppressive activity, the manifestation of which depends on the microenvironmental factors, including O2 level. Here we examined the effects of MSCs on transcriptomic profile of allogeneic phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMCs) after interaction at ambient (20%) or "physiological" hypoxia (5%) O2. As revealed with microarray analysis, PBMC transcriptome at 20% O2 was more affected, which was manifested as differential expression of more than 300 genes, whereas under 5% O2 220 genes were changed. Most of genes at 20% O2 were downregulated, while at hypoxia most of genes were upregulated. Altered gene patterns were only partly overlapped at different O2 levels. A set of altered genes at hypoxia only was of particular interest. According to Gene Ontology a part of above genes was responsible for adhesion, cell communication, and immune response. At both oxygen concentrations, MSCs demonstrated effective immunosuppression manifested as attenuation of T cell activation and proliferation as well as anti-inflammatory shift of cytokine profile. Thus, MSC-mediated immunosuppression is executed with greater efficacy at a "physiological" hypoxia, since the same result has been achieved through a change in the expression of a fewer genes in target PBMCs.

Immortalized Canine Adipose-Derived Mesenchymal Stem Cells Maintain the Immunomodulatory Capacity of the Original Primary Cells

Mesenchymal stem cells (MSCs) are a promising cell source for stem cell therapy of intractable diseases in veterinary medicine, but donor-dependent cellular heterogeneity is an issue that influences therapeutic efficacy. Thus, we previously established immortalized cells that maintain the fundamental properties of primary cells, but functional evaluation had not been performed. Therefore, we evaluated the immunomodulatory capacity of the immortalized canine adipose-derived MSCs (cADSCs) in vitro and in vivo to investigate whether they maintain primary cell functions. C57BL/6J mice were treated with dextran sulfate sodium (DSS) to induce colitis, injected intraperitoneally with immortalized or primary cADSCs on day 2 of DSS treatment, and observed for 10 days. Administration of immortalized cADSCs improved body weight loss and the disease activity index (DAI) in DSS-induced colitic mice by shifting peritoneal macrophage polarity from the M1 to M2 phenotype, suppressing T helper (Th) 1/Th17 cell responses and inducing regulatory T (Treg) cells. They also inhibited the proliferation of mouse and canine T cells in vitro. These immunomodulatory effects were comparable with primary cells. These results highlight the feasibility of our immortalized cADSCs as a cell source for stem cell therapy with stable therapeutic efficacy because they maintain the immunomodulatory capacity of primary cells.

The effect of TLR3 priming conditions on MSC immunosuppressive properties

BACKGROUND

Mesenchymal stromal cells (MSCs) have regenerative and immunomodulatory properties, making them suitable for cell therapy. Toll-like receptors (TLRs) in MSCs respond to viral load by secreting immunosuppressive or proinflammatory molecules. The expression of anti-inflammatory molecules in MSCs can be altered by the concentration and duration of exposure to the TLR3 ligand polyinosinic-polycytidylic acid (poly(I:C)). This study aimed to optimize the preconditioning of MSCs with poly(I:C) to increase immunosuppressive effects and to identify MSCs with activated TLR3 (prMSCs).

METHODS

Flow cytometry and histochemical staining were used to analyze MSCs for immunophenotype and differentiation potential. MSCs were exposed to poly(I:C) at 1 and 10 μg/mL for 1, 3, and 24 h, followed by determination of the expression of IDO1, WARS1, PD-L1, TSG-6, and PTGES2 and PGE2 secretion. MSCs and prMSCs were cocultured with intact (J-) and activated (J+) Jurkat T cells. The proportion of proliferating and apoptotic J+ and J- cells, IL-10 secretion, and IL-2 production after cocultivation with MSCs and prMSCs were measured. Liquid chromatography-mass spectrometry and bioinformatics analysis identified proteins linked to TLR3 activation in MSCs.

RESULTS

Poly(I:C) at 10 μg/mL during a 3-h incubation caused the highest expression of immunosuppression markers in MSCs. Activation of prMSCs caused a 18% decrease in proliferation and a one-third increase in apoptotic J+ cells compared to intact MSCs. Cocultures of prMSCs and Jurkat cells had increased IL-10 and decreased IL-2 in the conditioned medium. A proteomic study of MSCs and prMSCs identified 53 proteins with altered expression. Filtering the dataset with Gene Ontology and Reactome Pathway revealed that poly(I:C)-induced proteins activate the antiviral response. Protein‒protein interactions by String in prMSCs revealed that the antiviral response and IFN I signaling circuits were more active than in native MSCs. prMSCs expressed more cell adhesion proteins (ICAM-I and Galectin-3), PARP14, PSMB8, USP18, and GBP4, which may explain their anti-inflammatory effects on Jurkat cells.

CONCLUSIONS

TLR3 activation in MSCs is dependent on exposure time and poly(I:C) concentration. The maximum expression of immunosuppressive molecules was observed with 10 µg/mL poly(I:C) for 3-h preconditioning. This priming protocol for MSCs enhances the immunosuppressive effects of prMSCs on T cells.

Progress in research on mesenchymal stem cells and their extracellular vesicles for treating fibrosis in systemic sclerosis

Systemic sclerosis (SSc) refers to an autoimmune disease characterized by immune dysfunction, vascular endothelial damage, and multi-organ fibrosis. Thus far, this disease is incurable, and its high mortality rate is significantly correlated with fibrotic events. Fibrosis has been confirmed as a difficult clinical treatment area that should be urgently treated in clinical medicine. Mesenchymal stem cells (MSCs) exhibit immunomodulatory, pro-angiogenic, and anti-fibrotic functions. MSCs-derived extracellular vesicles (EVs) have aroused rising interest as a cellular component that retains the functions of MSCs while circumventing the possible adverse effects of MSCs. Moreover, EVs have great potential in treating SSc. In this study, the current research progress on MSCs and their EVs for treating fibrosis in SSc was reviewed, with an aim to provide some reference for future MSCs and their EVs in treating SSc.

Influence of type 2 diabetes and obesity on adipose mesenchymal stem/stromal cell immunoregulation

Type 2 diabetes (T2D), associated with obesity, represents a state of metabolic inflammation and oxidative stress leading to insulin resistance and progressive insulin deficiency. Adipose-derived stem cells (ASCs) are adult mesenchymal stem/stromal cells identified within the stromal vascular fraction of adipose tissue. These cells can regulate the immune system and possess anti-inflammatory properties. ASCs are a potential therapeutic modality for inflammatory diseases including T2D. Patient-derived (autologous) rather than allogeneic ASCs may be a relatively safer approach in clinical perspectives, to avoid occasional anti-donor immune responses. However, patient characteristics such as body mass index (BMI), inflammatory status, and disease duration and severity may limit the therapeutic utility of ASCs. The current review presents human ASC (hASC) immunoregulatory mechanisms with special emphasis on those related to T lymphocytes, hASC implications in T2D treatment, and the impact of T2D and obesity on hASC immunoregulatory potential. hASCs can modulate the proliferation, activation, and functions of diverse innate and adaptive immune cells via direct cell-to-cell contact and secretion of paracrine mediators and extracellular vesicles. Preclinical studies recommend the therapeutic potential of hASCs to improve inflammation and metabolic indices in a high-fat diet (HFD)-induced T2D disease model. Discordant data have been reported to unravel intact or detrimentally affected immunomodulatory functions of ASCs, isolated from patients with obesity and/or T2D patients, in vitro and in vivo. Numerous preconditioning strategies have been introduced to potentiate hASC immunomodulation; they are also discussed here as possible options to potentiate the immunoregulatory functions of hASCs isolated from patients with obesity and T2D.

OPG gene-modified adipose-derived stem cells improve bone formation around implants in osteoporotic rat maxillae

Background

Osteoporosis is a significant barrier to the use of dental implants in the elderly for the treatment of tooth defects. Adipose derived stem cells (ADSCs) have demonstrated extensive potential for tissue repair and regeneration. The present study aimed to investigate the effectiveness of ADSCs engineered to express high levels of osteoprotegerin (OPG) for the treatment of bone loss in implant dentistry caused by estrogen deficiency.

Methods

A rat model of osteoporosis was established through double oophorectomy, and the rats were treated by gene modified cells Adv-OPG-ADSCs. The effects of the treatment on maxilla tissue changes were evaluated using HE staining and micro-CT. Additionally, ALP and TRAP staining were used to assess osteoblast and osteoclast alterations. Finally, the changes in related osteoblast and osteoclast indicators were measured by RT-qPCR, Western blot, and ELISA.

Results

The successfully generated high-OPG-expressing ADSCs led to increase of cell viability, proliferation, and osteoblast differentiation. Treatment with Adv-OPG-ADSCs significantly ameliorated maxillary morphology, trabecular volume reduction, and bone mineral density decline in the model of estrogen-deficient maxillary implant dentistry. Furthermore, the treatment was beneficial to promoting the generation of osteoblasts and inhibiting the generation of osteoclast. Adv-OPG-ADSCs increased OPG, ALP, OCN, and Runx-2 expressions in the maxilla while suppressing RANKL expression, and also increased the concentration of COL I and PINP, as well as decreased the concentration of CTX-1.

Conclusion

Adv-OPG-ADSCs promote the formation of osteoblasts and inhibit the generation of osteoclasts, thereby inhibiting bone absorption, facilitating bone formation, and promoting the repair of maxillary bone after dental implantation in the presence of osteoporosis-related complications, especially in the setting of estrogen deficiency, providing scientific basis for the application of Adv-OPG-ADSCs in the treatment of implant related osteoporosis.

Multiple Injections of Adipose-Derived Stem Cells Improve Graft Survival in Human-to-Rat Skin Xenotransplantation through Immune Modulation

BACKGROUND

Adipose-derived stem cells (ADSCs) exert immunomodulatory effects in the treatment of transplant rejection. This study aimed to evaluate the effects of ADSCs on the skin graft survival in a human-to-rat xenograft transplantation model and to compare single and multiple injections of ADSCs.

METHODS

Full-thickness human skin xenografts were transplanted into the backs of Sprague-Dawley rats. The rats were injected subcutaneously on postoperative days 0, 3, and 5. The injections were as follows: triple injections of phosphate-buffered saline (PBS group), a single injection of ADSCs and double injections of PBS (ADSC × 1 group), and triple injections of ADSCs (ADSC × 3 group). The immunomodulatory effects of ADSCs on human skin xenografts were assessed.

RESULTS

Triple injections of ADSCs considerably delayed cell-mediated xenograft rejection compared with the PBS and ADSC × 1 groups. The vascularization and collagen type 1-3 ratios in the ADSC × 3 group were significantly higher than those in the other groups. In addition, intragraft infiltration of CD3-, CD4-, CD8-, and CD68-positive cells was reduced in the ADSC × 3 group. Furthermore, in the ADSC × 3 group, the expression levels of proinflammatory cytokine interferon-gamma (IFN-γ) were decreased and immunosuppressive prostaglandin E synthase (PGES) was increased in the xenograft and lymph node samples.

CONCLUSION

This study presented that triple injections of ADSCs appeared to be superior to a single injection in suppressing cell-mediated xenograft rejection. The immunomodulatory effects of ADSCs are associated with the downregulation of IFN-γ and upregulation of PGES in skin xenografts and lymph nodes.

Paracrine signalling between keratinocytes and SVF cells results in a new secreted cytokine profile during wound closure

Stromal vascular fraction (SVF) cells, and the adipose-derived mesenchymal stem cells they contain, have shown enhanced wound healing in vitro and in vivo, yet their clinical application has been limited. In this regard, understanding the mechanisms that govern SVF-enhanced wound healing would improve their application in the clinic. Here, we show that the SVF cells and keratinocytes engage in a paracrine crosstalk during wound closure, which results in a new cytokine profile that is distinct from the cytokines regularly secreted by either cell type on their own. We identify 11 cytokines, 5 of which are not regularly secreted by the SVF cells, whose expressions are significantly increased during wound closure by the keratinocytes. This new cytokine profile could be used to accelerate wound closure and initiate re-epithelialization without the need to obtain the SVF cells from the patient.

Stromal vascular fraction in the treatment of myositis

Muscle regeneration is a physiological process that converts satellite cells into mature myotubes under the influence of an inflammatory environment progressively replaced by an anti-inflammatory environment, with precise crosstalk between immune and muscular cells. If the succession of these phases is disturbed, the immune system can sometimes become auto-reactive, leading to chronic muscular inflammatory diseases, such as myositis. The triggers of these autoimmune myopathies remain mostly unknown, but the main mechanisms of pathogenesis are partially understood. They involve chronic inflammation, which could be associated with an auto-reactive immune response, and gradually with a decrease in the regenerative capacities of the muscle, leading to its degeneration, fibrosis and vascular architecture deterioration. Immunosuppressive treatments can block the first part of the process, but sometimes muscle remains weakened, or even still deteriorates, due to the exhaustion of its capacities. For patients refractory to immunosuppressive therapies, mesenchymal stem cells have shown interesting effects but their use is limited by their availability. Stromal vascular fraction, which can easily be extracted from adipose tissue, has shown good tolerance and possible therapeutic benefits in several degenerative and autoimmune diseases. However, despite the increasing use of stromal vascular fraction, the therapeutically active components within this heterogeneous cellular product are ill-defined and the mechanisms by which this therapy might be active remain insufficiently understood. We review herein the current knowledge on the mechanisms of action of stromal vascular fraction and hypothesise on how it could potentially respond to some of the unmet treatment needs of refractory myositis.

Bone marrow mesenchymal stem cells' osteogenic potential: superiority or non-superiority to other sources of mesenchymal stem cells?

Skeletal problems are an increasing issue due to the increase in the global aging population. Different statistics reports show that today, the global population is aging that results in skeletal problems, increased health system costs, and even higher mortality associated with skeletal problems. Common treatments such as surgery and bone grafts are not always effective and in some cases, they can even cause secondary problems such as infections or improper repair. Cell therapy is a method that can be utilized along with common treatments independently. Mesenchymal stem cells (MSCs) are a very important and efficient source in terms of different diseases, especially bone problems. These cells are present in different tissues such as bone marrow, adipose tissue, umbilical cord, placenta, dental pulp, peripheral blood, amniotic fluid and others. Among the types of MSCs, bone marrow mesenchymal stem cells (BMMSCs) are the most widely used source of these cells, which have appeared to be very effective and promising in terms of skeletal diseases, especially compared to the other sources of MSCs. This study focuses on the specific potential and content of BMMSCs from which the specific capacity of these cells originates, and compares their osteogenic potential with other types of MSCs, and also the future directions in the application of BMMSCs as a source for cell therapy.

Adipose Tissue-Derived Stromal/Stem Cells Transplantation with Cholecalciferol Supplementation in Recent-Onset Type 1 Diabetes Patients: Twelve Months Follow-Up

To evaluate safety and therapeutic effect along 12 months of allogenic adipose tissue-derived stromal/stem cells (ASCs) transplantation with cholecalciferol (VITD) in patients with recent-onset type 1 diabetes (T1D). Prospective, phase II, open trial, pilot study in which patients with recent onset T1D received ASCs (1xKgx106 cells) and VITD 2000UI/day for 12 months (group 1) and were compared to controls with standard insulin therapy (group 2). Adverse events, C-peptide area under the curve (CPAUC), insulin dose, HbA1c and frequency of FoxP3+ in CD4+ or CD8+ T-cells(flow cytometry) were evaluated at baseline(T0), after 3(T3), 6(T6) and 12 months(T12). Eleven patients completed follow up (7:group 1;4:group 2). Group 1 had lower insulin requirement at T3(0.24±0.18vs0.53±0.23UI/kg,p=0.04), T6(0.24±0.15vs0.66±0.33 UI/kg,p=0.04) and T12(0.39±0.15vs0.74±0.29 UI/Kg,p=0.04).HbA1c was lower at T6 (50.57±8.56vs72.25±10.34 mmol/mol,p=0.01), without differences at T12 (57.14±11.98 in group 1 vs. 73.5±14.57 mmol/min in group 2, p=0.16). CPAUC was not significantly different between groups at T0(p=0.07), higher in group 1 at T3(p=0.04) and T6(p=0.006), but similar at T12(p=0.23). IDAA1c was significantly lower in group 1 than group 2 at T3,T6 and T12 (p=0.006, 0.006 and 0.042, respectively). IDDA1c was inversely correlated to FoxP3 expression in CD4 and CD8+ T cells at T6 (p<0.001 and p=0.01, respectively). In group 1, one patient had recurrence of a benign teratoma that was surgically removed, not associated to the intervention. ASCs with VITD without immunosuppression were safe and associated lower insulin requirements, better glycemic control, and transient better pancreatic function in recent onset T1D, but the potential benefits were not sustained.

Multi-omics analysis of human mesenchymal stem cells shows cell aging that alters immunomodulatory activity through the downregulation of PD-L1

Mesenchymal stem cells (MSCs) possess potent immunomodulatory activity and have been extensively investigated for their therapeutic potential in treating inflammatory disorders. However, the mechanisms underlying the immunosuppressive function of MSCs are not fully understood, hindering the development of standardized MSC-based therapies for clinical use. In this study, we profile the single-cell transcriptomes of MSCs isolated from adipose tissue (AD), bone marrow (BM), placental chorionic membrane (PM), and umbilical cord (UC). Our results demonstrate that MSCs undergo a progressive aging process and that the cellular senescence state influences their immunosuppressive activity by downregulating PD-L1 expression. Through integrated analysis of single-cell transcriptomic and proteomic data, we identify GATA2 as a regulator of MSC senescence and PD-L1 expression. Overall, our findings highlight the roles of cell aging and PD-L1 expression in modulating the immunosuppressive efficacy of MSCs and implicating perinatal MSC therapy for clinical applications in inflammatory disorders.

Specific Features of Stromal Cells Isolated from the Two Layers of Subcutaneous Adipose Tissue: Roles of Their Secretion on Angiogenesis and Neurogenesis

Human-adipose-tissue-derived mesenchymal stromal cells (AD-MSCs) are currently being tested as autologous-cell-based therapies for use in tissue healing and regeneration. Recent studies have also demonstrated that AD-MSC-derived exosomes contribute to tissue repair and peripheral nerve regeneration. Subcutaneous abdominal adipose tissue (AAT) is divided into two layers: the superficial layer (sAAT) and the deep layer (dAAT). However, it is unclear whether there are particular characteristics of each layer in terms of AD-MSC regenerative potential. Using AD-MSCs purified and characterized from three abdominoplasties, we compared their secretomes and exosome functions to identify which layer may be most suitable as a source for cell therapy. Phenotypical analysis of the AD-MSCs containing stromal vascular fraction did not reveal any difference between the two layers. The AD-MSC secretomes showed a very similar pattern of cytokine content and both layers were able to release exosomes with identical characteristics. However, compared to the secretome, the released exosomes showed better biological properties. Interestingly, dAAT exosomes appeared to be more effective on neuromodulation, whereas neither sAAT nor dAAT-derived exosomes had significant effects on endothelial function. It thus appears that AD-MSC-derived exosomes from the two abdominal adipose tissue layers possess different features for cell therapy.

Immunomodulatory effect of human dedifferentiated fat cells: comparison with adipose-derived stem cells

Dedifferentiated fat cells (DFATs), which are originated by the dedifferentiation of adipocytes, display surface markers of mesenchymal stem cells and are able to differentiate into different cell types, thus, yielding a huge therapeutic potential in repairing damaged tissues and organs. The use of allogeneic stem cells from healthy donors constitutes the basis of a new strategy for cell therapy in the field of transplantation and the first requirement for allografts is determining their immunological properties. In this study, human DFATs and ADSCs were passaged as in vitro models to investigate their immunomodulatory effects. Phenotypic analysis of cell surface markers and three-line differentiation protocols were used to identify stem cells. The immunogenic phenotypes of DFATs and ADSCs were analyzed by flow cytometry and a mixed lymphocyte reaction was used to assess their immune function. The characteristics of stem cells were confirmed by phenotypic identification of cell surface markers and three-line differentiation. Flow cytometry analysis showed that P3 generation DFATs and ADSCs contained human leukocyte antigen (HLA) class I molecules, but did not express HLA class II molecules and costimulatory molecules CD40, CD80 and CD86. Moreover, allogeneic DFATs and ADSCs could not induce the proliferation of peripheral blood mononuclear cells (PBMCs). In addition, both populations were shown to inhibit the Concanavalin A-stimulated proliferation of PBMCs and act as third-party cells responsible for inhibiting the mixed lymphocyte response. DFATs have immunosuppressive properties similar to ADSCs. Based on this, allogeneic DFATs have potential applications in tissue repair or cell therapy.

Obesity and Fibrosis: Setting the Stage for Breast Cancer

Obesity is a rising health concern and is linked to a worsened breast cancer prognosis. Tumor desmoplasia, which is characterized by elevated numbers of cancer-associated fibroblasts and the deposition of fibrillar collagens within the stroma, may contribute to the aggressive clinical behavior of breast cancer in obesity. A major component of the breast is adipose tissue, and fibrotic changes in adipose tissue due to obesity may contribute to breast cancer development and the biology of the resulting tumors. Adipose tissue fibrosis is a consequence of obesity that has multiple sources. Adipocytes and adipose-derived stromal cells secrete extracellular matrix composed of collagen family members and matricellular proteins that are altered by obesity. Adipose tissue also becomes a site of chronic, macrophage-driven inflammation. Macrophages exist as a diverse population within obese adipose tissue and mediate the development of fibrosis through the secretion of growth factors and matricellular proteins and interactions with other stromal cells. While weight loss is recommended to resolve obesity, the long-term effects of weight loss on adipose tissue fibrosis and inflammation within breast tissue are less clear. Increased fibrosis within breast tissue may increase the risk for tumor development as well as promote characteristics associated with tumor aggressiveness.

Potential of Oral Cavity Stem Cells for Bone Regeneration: A Scoping Review

Bone loss is a common problem that ranges from small defects to large defects after trauma, surgery, or congenital malformations. The oral cavity is a rich source of mesenchymal stromal cells (MSCs). Researchers have documented their isolation and studied their osteogenic potential. Therefore, the objective of this review was to analyze and compare the potential of MSCs from the oral cavity for use in bone regeneration.

METHODS

A scoping review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. The databases reviewed were PubMed, SCOPUS, Scientific Electronic Library Online (SciELO), and Web of Science. Studies using stem cells from the oral cavity to promote bone regeneration were included.

RESULTS

A total of 726 studies were found, of which 27 were selected. The MSCs used to repair bone defects were (I) dental pulp stem cells of permanent teeth, (II) stem cells derived from inflamed dental pulp, (III) stem cells from exfoliated deciduous teeth, (IV) periodontal ligament stem cells, (V) cultured autogenous periosteal cells, (VI) buccal fat pad-derived cells, and (VII) autologous bone-derived mesenchymal stem cells. Stem cells associate with scaffolds to facilitate insertion into the bone defect and to enhance bone regeneration. The biological risk and morbidity of the MSC-grafted site were minimal. Successful bone formation after MSC grafting has been shown for small defects with stem cells from the periodontal ligament and dental pulp as well as larger defects with stem cells from the periosteum, bone, and buccal fat pad.

CONCLUSIONS

Stem cells of maxillofacial origin are a promising alternative to treat small and large craniofacial bone defects; however, an additional scaffold complement is required for stem cell delivery.

An analysis of the immunomodulatory properties of human spheroids from adipose-derived stem cells

AIMS

Current methods to induce tolerance following allotransplantation or in autoimmunity carry significant morbidity, and research is very active in investigating alternative methods which could minimize toxicity. Spheroids from adipose stem cells (SASCs) are increasingly gaining interest, they hold a great proliferative and differentiating potential. An immunomodulatory effect has not been investigated on SASCs yet. In this study, we analysed the immunomodulatory properties of SASCs and compared them to ADSCs.

MAIN METHODS

Adipose stem cells (SASCs and ADSCs) and peripheral blood mononuclear cells (PBMCs) were collected from healthy individuals. We analysed the cytokine production and proliferation of T cells co-cultured with adipose samples or conditioned medium.

KEY FINDINGS

SASCs modulated cytokines production and proliferation of heterologous and autologous T cells. In the heterologous assays, we observed a reduction of IFNγ and IL-17 production and an increase of IL-9 in γδ T cells. The soluble factors present in SASCs sovranatants were also able to induce a slight reduction of IFNγ and an increase of IL-9, IL-10 and IL-17 while they could not modulate the proliferative ability of γδ T cells. In the autologous assays, we observed a reduction of the proliferative ability of T cells in co-culture at different ratios with SASCs. Analysis of the SASCs secretome showed an increased IL-5, IL-10, IL-4 and IL-13 production compared to the ADSCs one, demonstrating greater anti-inflammatory properties.

SIGNIFICANCE

Our preliminary results support the idea that SASCs exert more pronounced biological immune modulation compared to the classical adherent ADSCs, especially in heterologous experimental settings.

Platelet-Rich stroma from Crohn's disease patients for treatment of perianal fistula shows a higher myeloid cell profile compared to non-IBD controls

BACKGROUND

New cell-based therapies are under investigation to improve perianal fistulizing Crohn's disease (pCD) healing. Autologous stromal vascular fraction combined with platelet-rich plasma (referred to as platelet-rich stroma [PRS]) is a new adipose-derived stromal therapy. The effect of Crohn's disease (CD) on adipose tissue, and adipose-derived therapies, is largely unknown. We characterized the cellular composition of subcutaneous lipoaspirate and PRS of pCD patients and non-Inflammatory Bowel Disease (IBD) controls.

METHODS

Consecutive pCD patients (≥18 years) and non-IBD controls, who underwent liposuction for the purpose of autologous PRS therapy, were included (October 2020 and March 2021). Mechanically fractionated lipoaspirate and the combined PRS product were analyzed for cell surface marker expression using fluorescence-activated cell sorting analysis.

RESULTS

Twenty-three patients (37.8 [IQR 30.7-45.0] years; 9 [39.1 %] male; 11CD patients) were included. Similar total number of cells were found in CD and non-IBD lipoaspirate (CD 8.23 ± 1.62*10⁵ cells/mL versus non-IBD 12.20 ± 3.39*10⁵). Presence of stromal cells, endothelial like cells, immune cells, T-cells, myeloid cells and M2/M1 macrophage ratio were similar in CD and non-IBD lipoaspirate. In PRS samples, more cells/mL were seen in CD patients (P = 0.030). Myeloid cells were more abundant in CD PRS samples (P = 0.007), and appeared to have a higher regulatory M2/M1 ratio. Interdonor variation was observed between lipoaspirate and PRS samples.

CONCLUSIONS

The composition of CD and non-IBD lipoaspirate were found to be similar and interdonor variation was observed. However, PRS from CD patients showed more myeloid cells with a regulatory phenotype. Crohn's disease does not appear to alter the immunological composition of adipose-derived products.

A Bibliometric and Visualization Analysis on the Research of Fat Grafting from 1945 to 2021

BACKGROUND

It is very important to generate a comprehensive assessment of the fat grafting field due to the rapid growth of scientific literature. The current study aimed to use bibliometric analysis to evaluate fat grafting research qualitatively and quantitatively and determine the research hotspots and trends in this field.

METHODS

Publications on fat grafting research were extracted from the Web of Science core collection database. VOSviewer 1.6.18 was applied to perform the bibliometric analysis of these articles.

RESULTS

A total of 2558 studies published by 594 different journals authored by 9097 researchers were contained in this study. In the co-authorship analysis, the bulk of the retrieved studies was conducted by the USA, followed by China, Italy and Japan, while the most productive institution, journal and author were Chinese Academy of Medicine Sciences, Plastic and Reconstruction Surgery and Klinger M, respectively. In the co-cited analysis, the most top cited author, journal, organization and country were Coleman Sr, Plastic and Reconstruction Surgery, New York University and the USA, respectively. The map of keywords occurrence revealed the most active research aspects were focused on "surgery," "cell," "breast reconstruction" and "survival" and the time overlay mapping showed that the most active research hotspots were "breast reconstruction" and "retention".

CONCLUSIONS

The research hotspots include the following four aspects: aesthetic surgeries, cell-assisted lipotransfer, breast reconstruction and grafted fat survival. Breast fat grafting and volume retention may be trends in the future. We are willing to provide more beneficial data to contribute valuable research for the fat grafting through this study.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Timing of Mesenchymal Stromal Cell Therapy Defines its Immunosuppressive Effects in a Rat Lung Transplantation Model

Cell therapy using mesenchymal stromal cells (MSCs) is being studied for its immunosuppressive effects. In organ transplantation, the amount of MSCs that accumulate in transplanted organs and other organs may differ depending on administration timing, which may impact their immunosuppressive effects. In vitro, adipose-derived mesenchymal stem cells (ADMSCs) suppress lymphocyte activation under cell-to-cell contact conditions. However, in vivo, it is controversial whether ADMSCs are more effective in accumulating in transplanted organs or in secondary lymphoid organs. Herein, we aimed to investigate whether the timing of ADMSC administration affects its immunosuppression ability in a rat lung transplantation model. In the transplantation study, rats were intramuscularly administered half the usual dose of tacrolimus (0.5 mg/kg) every 24 h after lung transplantation. ADMSCs (1 × 106) were administered via the jugular vein before (PreTx) or after (PostTx) transplantation. Cell tracking using quantum dots was performed. ADMSCs accumulated predominantly in the lung and liver; fewer ADMSCs were distributed in the grafted lung in the PreTx group than in the PostTx group. The rejection rate was remarkably low in the ADMSC-administered groups, particularly in the PostTx group. Serum tumor necrosis factor-α (TNF-α), interferon-γ, and interleukin (IL)-6 levels showed a greater tendency to decrease in the PreTx group than in the PostTx group. The proportion of regulatory T cells in the grafted lung 10 days after transplantation was higher in the PostTx group than in the PreTx group. PostTx administration suppresses rejection better than PreTx administration, possibly due to regulatory T cell induction by ADMSCs accumulated in the transplanted lungs, suggesting a mechanism different from that in heart or kidney transplantation that PreTx administration is more effective than PostTx administration. These results could help establish cell therapy using MSCs in lung transplantation.

Preclinical Short-term and Long-term Safety of Human Bone Marrow Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have become a promising therapeutic method. More safety data are needed to support clinical studies in more diseases. The aim of this study was to investigate the short- and long-term safety of human bone marrow-derived MSCs (hBMMSCs) in mice. In the present study, we injected control (saline infusion only), low (1.0 × 106/kg), medium (1.0 × 107/kg), and high (1.0 × 108/kg) concentrations of hBMMSCs into BALB/c mice. The safety of the treatment was evaluated by observing changes in the general condition, hematology, biochemical indices, pathology of vital organs, lymphocyte subsets, and immune factor levels on days 14 and 150. In the short-term toxicity test, no significant abnormalities were observed in the hematological and biochemical parameters between the groups injected with hBMMSCs, and no significant damage was observed in the major organs, such as the liver and lung. In addition, no significant differences were observed in the toxicity-related parameters among the groups in the long-term toxicity test. Our study also demonstrates that mice infused with different doses of hBMMSCs do not show abnormal immune responses in either short-term or long-term experiments. We confirmed that hBMMSCs are safe through a 150-day study, demonstrating that this is a safe and promising therapy and offering preliminary safety evidence to promote future clinical applications of hBMMSCs in different diseases.

Adipose-derived stem/stromal cells with heparin-enhanced anti-inflammatory and antifibrotic effects mitigate induced pulmonary fibrosis in mice

Interstitial lung disease (ILD) is a life-threatening pathological condition that causes respiratory failure and often presents as pulmonary fibrosis. Although it is treated using immunosuppressive and antifibrotic agents, the beneficial effects of these agents remain limited. Thus, the development of new therapeutic strategies for lung fibrosis is crucial. Mesenchymal stem/stromal cells (MSCs) have multilineage differentiation potential; additionally, they have anti-inflammatory and antifibrotic effects as well as the ability to modulate the immune response and modify the microenvironment at the site of engraftment. Numerous adipose-derived MSCs (ASCs) are present in the adipose tissue. Heparin and low-molecular-weight heparin (LMWH) mediate the secretion of several cytokines and growth factors with cell migratory and antifibrotic effects. This study aimed to confirm the therapeutic effect of LMWH-activated ASCs on ILD. Mouse ASCs (mASCs) were cultured in an LMWH-supplemented medium. LMWH significantly increased the number of mASC and enhanced their migratory, anti-inflammatory, and antifibrotic effects. Furthermore, mice with bleomycin-induced pulmonary fibrosis were intravenously administered LMWH-activated mASCs. The relative mRNA expression of inflammation-related genes in ILD lungs was significantly lower in the treatment group than in the pathological model group. Our findings suggest that LMWH-activated mASC administration reduces lung fibrosis.

Searching for the Optimal Donor for Allogenic Adipose-Derived Stem Cells: A Comprehensive Review

Adipose-derived stem cells comprise several clinically beneficial qualities that have been explored in basic research and have motivated several clinical studies with promising results. After being approved in the European Union, UK, Switzerland, Israel, and Japan, allogeneic adipose-derived stem cells (darvadstrocel) have been recently granted a regenerative medicine advanced therapy (RMAT) designation by US FDA for complex perianal fistulas in adults with Crohn's disease. This huge scientific step is likely to impact the future spread of the indications of allogeneic adipose-derived stem cell applications. The current knowledge on adipose stem cell harvest describes quantitative and qualitative differences that could be influenced by different donor conditions and donor sites. In this comprehensive review, we summarize the current knowledge on the topic and propose donor profiles that could provide the optimal initial quality of this living drug, as a starting point for further applications and studies in different pathological conditions.

Enforced mesenchymal stem cell tissue colonization counteracts immunopathology

Mesenchymal stem/stromal cells (MSCs) are distributed within all tissues of the body. Though best known for generating connective tissue and bone, these cells also display immunoregulatory properties. A greater understanding of MSC cell biology is urgently needed because culture-expanded MSCs are increasingly being used in treatment of inflammatory conditions, especially life-threatening immune diseases. While studies in vitro provide abundant evidence of their immunomodulatory capacity, it is unknown whether tissue colonization of MSCs is critical to their ability to dampen/counteract evolving immunopathology in vivo. To address this question, we employed a murine model of fulminant immune-mediated inflammation, acute graft-versus-host disease (aGvHD), provoked by donor splenocyte-enriched full MHC-mismatched hematopoietic stem cell transplant. aGvHD induced the expression of E-selectin within lesional endothelial beds, and tissue-specific recruitment of systemically administered host-derived MSCs was achieved by enforced expression of HCELL, a CD44 glycoform that is a potent E-selectin ligand. Compared to mice receiving HCELL⁻ MSCs, recipients of HCELL⁺ MSCs had increased MSC intercalation within aGvHD-affected site(s), decreased leukocyte infiltrates, lower systemic inflammatory cytokine levels, superior tissue preservation, and markedly improved survival. Mechanistic studies reveal that ligation of HCELL/CD44 on the MSC surface markedly potentiates MSC immunomodulatory activity by inducing MSC secretion of a variety of potent immunoregulatory molecules, including IL-10. These findings indicate that MSCs counteract immunopathology in situ, and highlight a role for CD44 engagement in unleashing MSC immunobiologic properties that maintain/establish tissue immunohomeostasis.

Donor and Recipient Adipose-Derived Mesenchymal Stem Cell Therapy for Rat Lung Transplantation

BACKGROUND

Mesenchymal stem cells (MSCs) are beginning to be proven as immunosuppressant in the field of organ transplantation. However, the effects of MSC origin (donor or recipient) on immunosuppression are not clear. Hence, we investigated the effects of recipient and donor adipose-derived MSCs (ADMSCs) on immunosuppression in a rat lung transplantation model.

METHODS

Subjects were divided into no treatment, tacrolimus administration, recipient ADMSC administration, donor ADMSC administration, and mixed donor and recipient ADMSC administration groups. ADMSC-administered groups were also treated with tacrolimus. Histologic study, immunofluorescence, immunohistochemistry, enzyme-linked immunosorbent assay, and polymerase chain reaction were used for various analyses.

RESULTS

Fluorescently labeled ADMSCs were predominant in the grafted donor lung, but not in the recipient lung, on day 5. On day 7, the pathologic rejection grades of the grafted donor lung were significantly lower in the ADMSC-administered groups (P < .05) and did not differ among these groups. Although serum hepatocyte growth factor and vascular endothelial growth factor levels did not differ among the groups, interleukin 10 level was slightly higher in the ADMSC-administered groups. The numbers of infiltrating regulatory T cells in the grafted lung were significantly higher in the ADMSC-administered groups (P < .05) but did not differ with cell origin. Transcriptional analysis suggested interleukin 6 suppression to be the main overlapping immunosuppressive mechanism, regardless of origin. Therefore, a donor or recipient origin may not influence the immunosuppressive efficacy of ADMSCs in our rat lung transplantation model.

CONCLUSIONS

Collectively, the results indicate that allogenic ADMSCs, regardless of their origin, may exert similar immunosuppressive effects in clinical organ transplantation.

Delayed onset, immunomodulation, and lifespan improvement of SOD1G93A mice after intravenous injection of human mesenchymal stem cells derived from adipose tissue

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the selective and progressive loss of motor neurons from the spinal cord, brain stem, and motor cortex. Although the hallmark of ALS is motor neuron degeneration, astrocytes, microglia, and T cells actively participate. Pharmacological treatment with riluzole has little effect on the lifespan of the patient. Thus, the development of new therapeutic strategies is of utmost importance. The objective of this study was to verify whether human mesenchymal stem cells (hMSCs) from adipose tissue have therapeutic potential in SOD1^G93A transgenic mice. The treatment was carried out in the asymptomatic phase of the disease (10th week) by a single systemic application of ad-hMSCs (1 ×10⁵ cells). The animals were sacrificed at the 14th week (the initial stage of symptoms) or the end-stage (ES) of the disease. The lumbar spinal cords were dissected and processed for Nissl staining (neuronal survival), immunohistochemistry (gliosis and synaptic preservation), and gene transcript expression (qRT-PCR). Behavioral analyses considering the onset of disease and its progression, neurological score, body weight, and motor control (rotarod test) started on the 10th week and were performed every three days until the ES of the disease. The results revealed that treatment with ad-hMSCs promoted greater neuronal survival (44%) than vehicle treatment. However, no effect was seen at the ES of the disease. Better structural preservation of the ventral horn in animals treated with ad-hMSCs was observed, together with decreased gliosis and greater synapse protection. In line with this, we found that the transcript levels of Hgf1 were upregulated in ad-hMSCs-treated mice. These results corroborate the behavioral data showing that ad-hMSCs had delayed motor deficits and reduced weight loss compared to vehicle animals. Additionally, cell therapy delayed the course of the disease and significantly improved survival by 20 days. Overall, our results indicate that treatment with ad-hMSCs has beneficial effects, enhancing neuronal survival and promoting a less degenerative neuronal microenvironment. Thus, this may be a potential therapy to improve the quality of life and to extend the lifespan of ALS patients.

Topical applications of allogeneic adipose-derived mesenchymal stem cells ameliorate the canine keratoconjunctivitis sicca

Background

Canine keratoconjunctivitis sicca (KCS) is predominantly an immune-mediated disease. Current therapy of canine KCS is mainly by immunosuppressant, but the effectiveness was limited in some patients. In the past few years, some studies showed the results of the use of mesenchymal stem cells in treating canine KCS via periocular injections. However, the periocular injection procedure requires sedation or general anesthesia, and may lead to iatrogenic or incidental injury during the injection process. The aim of this study was to investigate the efficacy of topical allogenic canine adipose-derived mesenchymal stem cells (cAD-MSCs) in clinical patients of canine KCS.

Results

The cAD-MSCs used in this study were characterized for their capability of tri-lineage differentiation and immunomodulatory properties. In addition, preparation methods for eye drops of cAD-MSCs was developed and its optimal preservation was tested. The canine KCS patients were recruited for clinical trial and divided into two groups based on their history of previous treatment. All patients received topical cAD-MSCs treatment once per week for 6 consecutive weeks and complete ophthalmic examinations were performed 1 week before treatment (week 0) and at 3rd, 6th, 9th weeks, respectively. The results showed that the quantity and quality of tears have improved significantly following topical cAD-MSCs treatment based on Schirmers tear test-1 and tear break-up time. More than half of all patients were found improved in the tear quantity. In particular, 56.5% of the patients that were unresponsive to prior immunosuppressant therapy had an effective increase in tear volume. The severity of clinical signs was also ameliorated according to the numeric rating scale score from both patient owners and the clinician.

Conclusion

To sum up, topical cAD-MSCs may be beneficial especially in KCS patients with poor owner compliance for frequent daily use of eye drops or those who are unresponsive to immunosuppressant therapy.

The Dual Role of Mesenchymal Stromal Cells and Their Extracellular Vesicles in Carcinogenesis

Simple Summary

Extracellular vesicles (EVs) are membrane structures that play the role of intermediaries between tumor cells and the tumor microenvironment (TME) because they have the ability to transport lipids, transcription factors, mRNA, and proteins. Mesenchymal stem cells (MSCs) are a major component of the TME and may have different effects on tumor progression using EVs. This review includes information about various studies which have reported that EVs from MSCs can have either antitumor or pro-tumor effects, depending on both the tumor type and developmental stage. It provides an overview of the published data on EV MSCs and their effect on tumor cells. In addition, the use of EV MSCs for the development of new methods for treating oncological diseases is described.

Abstract

Mesenchymal stem cells (MSCs) are a major component of the tumor microenvironment (TME) and play an important role in tumor progression. MSCs remodel the extracellular matrix, participate in the epithelial–mesenchymal transition, promote the spread of metastases, and inhibit antitumor immune responses in the TME; however, there are also data pertaining to the antitumor effects of MSCs. MSCs activate the cell death mechanism by modulating the expression of proteins involved in the regulation of the cell cycle, angiogenesis receptors, and proapoptotic proteins. One of the main ways in which MSCs and TME interact is through the production of extracellular vesicles (EVs) by cells. Currently, data on the effects of both MSCs and their EVs on tumor cells are rather contradictory. Various studies have reported that EVs from MSCs can have either antitumor or pro-tumor effects, depending on both the tumor type and developmental stage. In this review, we discuss published data on EV MSCs and their effect on tumor cells. The molecular composition of vesicles obtained from MSCs is also presented in the review. In addition, the use of EV MSCs for the development of new methods for treating oncological diseases is described.

Comparison of Stromal Vascular Fraction and Adipose-Derived Stem Cells for Protection of Renal Function in a Rodent Model of Ischemic Acute Kidney Injury

Aims

Few studies have compared the use of different cell types derived from adipose tissue or the optimal route for efficient and safe cell delivery in ischemic acute kidney injury (AKI). We compared the abilities of stromal vascular fraction (SVF) and adipose-derived stem cells (ADSC), injected via three different routes, to protect renal function in a rodent model of ischemic AKI.

Methods

Ninety male Sprague-Dawley rats were randomly divided into 9 groups: sham, nephrectomy control, AKI control, transaortic renal arterial SVF injection, renal parenchymal SVF injection, tail venous SVF injection, transaortic renal arterial ADSC injection, renal parenchymal ADSC injection, and tail venous ADSC injection groups. Their renal function was assessed 4 days before and 1, 2, 3, 4, 7, and 14 days after surgical procedures to induce ischemic AKI. The histomorphometric studies were performed 14 days after surgical procedures.

Results

Renal parenchymal injection of SVF notably reduced the level of serum blood urea nitrogen and creatinine elevation compared to the AKI control group. Renal parenchymal injection of SVF notably reduced the level of creatinine clearance decrease. In addition, collagen content was lower in the renal parenchymal SVF injection group, and fibrosis was reduced. Apoptosis was reduced in the renal parenchymal SVF injection group, and proliferation was increased. The expression levels of antioxidative markers such as glutathione reductase and peroxidase were higher in the renal parenchymal SVF injection group.

Conclusions

Our findings suggest that renal function is protected from ischemic AKI through renal parenchymal injection of SVF, which has enhanced antifibrotic, antiapoptotic, and antioxidative effects.

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.

Bone Healing Materials in the Treatment of Recalcitrant Nonunions and Bone Defects

The usual treatment for bone defects and recalcitrant nonunions is an autogenous bone graft. However, due to the limitations in obtaining autogenous bone grafts and the morbidity associated with their procurement, various bone healing materials have been developed in recent years. The three main treatment strategies for bone defects and recalcitrant nonunions are synthetic bone graft substitutes (BGS), BGS combined with bioactive molecules, and BGS and stem cells (cell-based constructs). Regarding BGS, numerous biomaterials have been developed to prepare bone tissue engineering scaffolds, including biometals (titanium, iron, magnesium, zinc), bioceramics (hydroxyapatite (HA)), tricalcium phosphate (TCP), biopolymers (collagen, polylactic acid (PLA), polycaprolactone (PCL)), and biocomposites (HA/MONs@miR-34a composite coating, Bioglass (BG)-based ABVF-BG (antibiotic-releasing bone void filling) putty). Bone tissue engineering scaffolds are temporary implants that promote tissue ingrowth and new bone regeneration. They have been developed to improve bone healing through appropriate designs in terms of geometric, mechanical, and biological performance. Concerning BGS combined with bioactive molecules, one of the most potent osteoinductive growth factors is bone morphogenetic proteins (BMPs). In recent years, several natural (collagen, fibrin, chitosan, hyaluronic acid, gelatin, and alginate) and synthetic polymers (polylactic acid, polyglycolic acid, polylactic-coglycolide, poly(e-caprolactone) (PCL), poly-p-dioxanone, and copolymers consisting of glycolide/trimethylene carbonate) have been investigated as potential support materials for bone tissue engineering. Regarding BGS and stem cells (cell-based constructs), the main strategies are bone marrow stromal cells, adipose-derived mesenchymal cells, periosteum-derived stem cells, and 3D bioprinting of hydrogels and cells or bioactive molecules. Currently, significant research is being performed on the biological treatment of recalcitrant nonunions and bone defects, although its use is still far from being generalized. Further research is needed to investigate the efficacy of biological treatments to solve recalcitrant nonunions and bone defects.