Comparison of mesenchymal stem cells from different tissues to suppress T-cell activation

Pain-relieving Effects of Autologous Fat Grafting in Breast Cancer Surgery: A Scoping Review

Background

Chronic pain is relatively common after breast cancer surgery, including breast reconstruction. Autologous fat grafting (AFG) has gained attention as a novel method for breast reconstruction, and recent clinical studies have also shown effects of AFG on alleviation of chronic pain after breast cancer surgery. Our objective was to conduct a scoping review of studies that have examined these effects with clearly defined clinical outcomes.

Methods

A literature search was conducted using three databases: PubMed, MEDLINE, and Google Scholar, following PRISMA guidelines and the Arkesy and O'Malley framework. The search focused on clinical studies of the effects of AFG on chronic pain after breast cancer surgery. All studies reporting functional outcomes, return to work, and secondary surgery in a repeat operation were identified.

Results

Of the 148 studies identified in the search, 11 studies with a total of 684 patients were included in the review. The average volume of fat grafted was approximately 128 mL over an average of 1.6 sessions. The most common time point for assessment was 1 year post-AFG. In all studies with an evidence level of 3 or lower, AFG showed positive results in alleviating pain after breast cancer surgery. However, one of the three randomized controlled trials did not show clinically significant effects.

Conclusions

Most of the studies examined in this review suggested pain-relieving effects of AFG. However, there was one randomized controlled trial in which these effects were not confirmed, indicating a need for further accumulation of cases and performance of new, well-designed randomized controlled trials.

Immunologic barriers in liver transplantation: a single-cell analysis of the role of mesenchymal stem cells

Background

This study aimed to analyze the biomarkers that may reliably indicate rejection or tolerance and the mechanism that underlie the induction and maintenance of liver transplantation (LT) tolerance related to immunosuppressant or mesenchymal stem cells (MSCs).

Methods

LT models of Lewis-Lewis and F344-Lewis rats were established. Lewis-Lewis rats model served as a control (Syn). F344-Lewis rats were treated with immunosuppressant alone (Allo+IS) or in combination with MSCs (Allo+IS+MSCs). Intrahepatic cell composition particularly immune cells was compared between the groups by single-cell sequencing. Analysis of subclusters, KEGG pathway analysis, and pseudotime trajectory analysis were performed to explore the potential immunoregulatory mechanisms of immunosuppressant alone or combined with MSCs.

Results

Immunosuppressants alone or combined with MSCs increases the liver tolerance, to a certain extent. Single-cell sequencing identified intrahepatic cell composition signature, including cell subpopulations of B cells, cholangiocytes, endothelial cells, erythrocytes, hepatic stellate cells, hepatocytes, mononuclear phagocytes, neutrophils, T cells, and plasmacytoid dendritic cells. Immunosuppressant particularly its combination with MSCs altered the landscape of intrahepatic cells in transplanted livers, as well as gene expression patterns in immune cells. MSCs may be included in the differentiation of T cells, classical monocytes, and non-classical monocytes.

Conclusion

These findings provided novel insights for better understanding the heterogeneity and biological functions of intrahepatic immune cells after LT treated by IS alone or in combination with MSCs. The identified markers of immune cells may serve as the immunotherapeutic targets for MSC treatment of liver transplant rejection.

Autologous Fat Grafting for Post-mastectomy Pain Syndrome: A Systematic Review and Meta-Analysis

Fat grafting has been described as a potential treatment for post-mastectomy pain syndrome (PMPS) following oncological breast surgery. The study's aim was to compare and contrast the current literature using a systematic review and meta-analysis to quantify the evidence. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. Databases, including MEDLINE, Google Scholar, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Central Register of Controlled Trials (CENTRAL), were searched. Data synthesis was conducted using Review Manager 5.4 (Cochrane Collaboration, London, UK), with 95% confidence intervals. All randomised controlled trials (RCT) and observational studies comparing lipofilling for PMPS were included. A total of six studies met the inclusion criteria with five articles being used in data analysis for the mean percentage reduction in visual analogue scale (VAS) score. The primary outcome measure was the mean percentage reduction in the VAS pain score. Secondary outcomes included the Neuropathic Pain Symptom Inventory (NPSI) and the quality of life assessments post treatment. Overall, a total of 266 patients received fat transfer for PMPS, and 164 were in the control group. The mean percentage reduction in VAS score was 19.8 (10.82, 28.82; p < 0.0001). Secondary outcomes, including health-related quality of life, showed good outcomes post fat transfer. This involved breast softness, cosmesis, and psychosocial well-being. The results from this meta-analysis suggest that autologous fat grafting is an efficacious treatment for reducing pain caused by PMPS. The authors suggest more high-quality trials are needed to enhance the current evidence base.

The Role of COX-2 and PGE2 in the Regulation of Immunomodulation and Other Functions of Mesenchymal Stromal Cells

The ability of MSCs to modulate the inflammatory environment is well recognized, but understanding the molecular mechanisms responsible for these properties is still far from complete. Prostaglandin E2 (PGE2), a product of the cyclooxygenase 2 (COX-2) pathway, is indicated as one of the key mediators in the immunomodulatory effect of MSCs. Due to the pleiotropic effect of this molecule, determining its role in particular intercellular interactions and aspects of cell functioning is very difficult. In this article, the authors attempt to summarize the previous observations regarding the role of PGE2 and COX-2 in the immunomodulatory properties and other vital functions of MSCs. So far, the most consistent results relate to the inhibitory effect of MSC-derived PGE2 on the early maturation of dendritic cells, suppressive effect on the proliferation of activated lymphocytes, and stimulatory effect on the differentiation of macrophages into M2 phenotype. Additionally, COX-2/PGE2 plays an important role in maintaining the basic life functions of MSCs, such as the ability to proliferate, migrate and differentiate, and it also positively affects the formation of niches that are conducive to both hematopoiesis and carcinogenesis.

Preclinical Evaluation of interferon-gamma primed human Wharton's jelly-derived mesenchymal stem cells

The potential of human mesenchymal stem cells (MSCs) for cell therapy has been investigated in numerous immune-mediated conditions; MSCs are considered one of the most promising cellular therapeutics to treat intractable diseases. Recently, approaches to prime MSCs have been investigated, thereby generating cellular products with enhanced potential for a variety of clinical applications. Interferon-gamma (IFN-γ) priming is a current approach used to increase the therapeutic efficacy of MSCs. In this study, we determined the systemic toxicity, tumorigenicity and biodistribution of IFN-γ-primed Wharton's jelly-derived (WJ)-MSCs in male and female BALB/c-nu/nu mice. There were no deaths or pathologic lesions in the mice treated with 5 × 10⁶ cells/kg IFN-γ-primed MSCs in the repeated dose study. In the tumorigenicity study, one of the subcutaneously treated mice showed bronchioloalveolar adenoma in the lung but tested negative for human-specific anti-mitochondrial antibody, suggesting the spontaneous murine origin of the adenoma. A biodistribution study using real-time quantitative polymerase chain reaction demonstrated the systemic IFN-γ-primed MSC clearance by day 28. Based on the toxicity, biodistribution, and tumorigenicity studies, we concluded that IFN-γ-primed MSCs at 5 × 10⁶ cells/kg do not induce tumor formation and adverse changes.

Use of an Autologous Diced Cartilage Graft and Fat Graft Combination to Improve Regeneration in Rhinoplasty

BACKGROUND

In rhinoplasty, many techniques are used to increase the permanence of the planned final shape of the nose. Cartilage grafts can be diced and applied directly to the nasal dorsum, or by wrapping with a material. We aim to show that mixing and using diced cartilage grafts with fat grafts can contribute to the viability of cartilage grafts by comparing our early postoperative and long-term results.

MATERIALS AND METHODS

A total of 228 cases were analyzed. Postoperative 1-month, 6-month, and 1.5-year photographs of the patients were compared and the places that descended on the nasal dorsum were measured. In addition, dorsal height was measured and compared. Preoperative and postoperative first-year rhinoplasty outcome evaluation scales were performed. Specimens from 6 patients were examined histopathologically.

RESULTS

After the first month, the mean regression in the dorsum was measured as 1.4 mm. The decrease in dorsal height between 1 month and 6 months was significantly greater than the decrease between 6 months and late periods. According to the rhinoplasty outcome evaluation (ROE) scale, the average preoperative score of the patients was 45, while the mean postoperative score was 81.5. The viability of chondrocyte cells was measured as 85-90% histopathologically.

CONCLUSION

This approach has been evaluated as an application that satisfies both the surgeon and the patient due to the advantages of fat grafts such as preventing the cartilage and osteotomy lines from being palpated in thin-skinned patients, holding the diced cartilage grafts together by acting as a glue, increasing the viability of cartilage grafts.

LEVEL OF EVIDENCE IV

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 Table of Contents or online Instructions to Authors www.springer.com/00266 .

Comparison of the differentiation abilities of bone marrow-derived mesenchymal stem cells and adipose-derived mesenchymal stem cells toward nucleus pulposus-like cells in three-dimensional culture

Nucleus pulposus cell (NPC) transplantation can be a potential therapeutic approach for intervertebral disc degeneration (IDD). However, low cell viability has restricted the therapeutic capacity of NPCs, and sources of natural NPCs are limited. Bone marrow-derived mesenchymal stem cells (BMSCs) and adipose-derived mesenchymal stem cells (ADSCs) can be differentiated toward NPC-like cells. However, it is unknown whether there are differences in the abilities of these two cell types to differentiate into NPC-like cells, or which cell type exhibits the best differentiation ability. The present study compared the abilities of BMSCs and ADSCs to differentiate toward NPC-like cells with or without a 3D culture system to lay a foundation for stem cell transplantation therapy for IDD. BMSCs were isolated from the rat whole bone marrow cell using the repeated adherent culture method. ADSCs were isolated from rat adipose tissues in the subcutaneous inguinal region using the enzyme digestion method. Cells were identified using flow cytometry. Cell viability was assessed via Cell Counting Kit-8 assays, and reverse transcription-quantitative PCR and western blotting were carried out to evaluate the expression of NPC markers and chondrocyte-specific genes. Glycosaminoglycans (GAGs) and proteoglycans were examined via Alcian blue and safranin O staining, respectively. ADSCs in 3D culture displayed the highest cell proliferative ability, compared with the 2D culture system and BMSC culture. In addition, ADSCs in 3D culture exhibited increased GAG and proteoglycan synthesis than BMSCs. Compared with BMSCs in 3D culture, ADSCs in 3D culture exhibited higher mRNA and protein expression of NPC marker genes (hypoxia-inducible factor 1-α, glucose transporter 1) and chondrocyte-specific genes (Sox-9, aggrecan and type II collagen). The present findings indicated that ADSCs exhibited a better ability to differentiate into NPC-like cells in 3D culture compared with BMSCs, which may be of value for the regeneration of intervertebral discs using cell transplantation therapy.

Mesenchymal Stromal Cells and Their Secretome: New Therapeutic Perspectives for Skeletal Muscle Regeneration

Mesenchymal stromal cells (MSCs) are multipotent cells found in different tissues: bone marrow, peripheral blood, adipose tissues, skeletal muscle, perinatal tissues, and dental pulp. MSCs are able to self-renew and to differentiate into multiple lineages, and they have been extensively used for cell therapy mostly owing to their anti-fibrotic and immunoregulatory properties that have been suggested to be at the basis for their regenerative capability. MSCs exert their effects by releasing a variety of biologically active molecules such as growth factors, chemokines, and cytokines, either as soluble proteins or enclosed in extracellular vesicles (EVs). Analyses of MSC-derived secretome and in particular studies on EVs are attracting great attention from a medical point of view due to their ability to mimic all the therapeutic effects produced by the MSCs (i.e., endogenous tissue repair and regulation of the immune system). MSC-EVs could be advantageous compared with the parental cells because of their specific cargo containing mRNAs, miRNAs, and proteins that can be biologically transferred to recipient cells. MSC-EV storage, transfer, and production are easier; and their administration is also safer than MSC therapy. The skeletal muscle is a very adaptive tissue, but its regenerative potential is altered during acute and chronic conditions. Recent works demonstrate that both MSCs and their secretome are able to help myofiber regeneration enhancing myogenesis and, interestingly, can be manipulated as a novel strategy for therapeutic interventions in muscular diseases like muscular dystrophies or atrophy. In particular, MSC-EVs represent promising candidates for cell free-based muscle regeneration. In this review, we aim to give a complete picture of the therapeutic properties and advantages of MSCs and their products (MSC-derived EVs and secreted factors) relevant for skeletal muscle regeneration in main muscular diseases.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles Regulate the Mitochondrial Metabolism via Transfer of miRNAs

Mesenchymal stromal cells (MSCs) are the most commonly tested adult progenitor cells in regenerative medicine. They stimulate tissue repair primarily through the secretion of immune-regulatory and pro-regenerative factors. There is increasing evidence that most of these factors are carried on extracellular vesicles (EVs) that are released by MSCs, either spontaneously or after activation. Exosomes and microvesicles are the most investigated types of EVs that act through uptake by target cells and cargo release inside the cytoplasm or through interactions with receptors expressed on target cells to stimulate downstream intracellular pathways. They convey different types of molecules, including proteins, lipids and acid nucleics among which, miRNAs are the most widely studied. The cargo of EVs can be impacted by the culture or environmental conditions that MSCs encounter and by changes in the energy metabolism that regulate the functional properties of MSCs. On the other hand, MSC-derived EVs are also reported to impact the metabolism of target cells. In the present review, we discuss the role of MSC-EVs in the regulation of the energy metabolism and oxidative stress of target cells and tissues with a focus on the role of miRNAs.

Mesenchymal stem cell as a novel approach to systemic sclerosis; current status and future perspectives

Systemic sclerosis is a rare chronic autoimmune disease with extensive microvascular injury, damage of endothelial cells, activation of immune responses, and progression of tissue fibrosis in the skin and various internal organs. According to epidemiological data, women's populations are more susceptible to systemic sclerosis than men. Until now, various therapeutic options are employed to manage the symptoms of the disease. Since stem cell-based treatments have developed as a novel approach to rescue from several autoimmune diseases, it seems that stem cells, especially mesenchymal stem cells as a powerful regenerative tool can also be advantageous for systemic sclerosis treatment via their remarkable properties including immunomodulatory and anti-fibrotic effects. Accordingly, we discuss the contemporary status and future perspectives of mesenchymal stem cell transplantation for systemic sclerosis.

Autologous fat grafting efficacy in treating PostMastectomy pain syndrome: A prospective multicenter trial of two Senonetwork Italia breast centers

Postmastectomy pain syndrome (PMPS) represents a common complication following breast surgery defined as a chronic neuropathic pain located in the front of the chest, in the axilla and in the upper arm that for more than 3 months after surgery. Several medications prove to be ineffective while autologous fat grafting revealed to be an innovative solution in the treatment of neuropathic pain syndromes based on retrospective studies. For this reason, we performed a prospective multicenter trial to reduce the memory bias and further increase the evidence of the results. From February 2018 to March 2019, 37 female patients aged between 18 and 80 years, underwent mastectomy or quadrantectomy with pathologic scarring and chronic persistent neuropathic pain, compatible with PMPS, are been included in the study and treated with autologous fat grafting. During the enrollment phase, patients were asked to estimate pain using the Visual Analogue Scale (VAS) and POSAS questionnaire in order to evaluate scar outcomes. The VAS scale, starting from 6.9 (1.3), decreased in the first month by 3.10 (1.59), continuing to fall by 0.83 (1.60) to 3 months and by 0.39 (2.09) at 6 months. Statistical analysis showed a significant reduction after 1 month (P < .0001) and 3 months (P < .005). All POSAS grades documented a statistically significant reduction (P < .0001) of the scores by both observers and patients. We observed that no significant association was found between age, BMI, menopausal status of patients, days from oncologic surgery to autologous fat grafting and reduction of VAS values over time while both smoking and axillary dissection were observed as the main factor significantly associated with a reduced clinical efficacy (respectively, P = .0227 and P = .0066). Our prospective multicenter trial confirms the efficacy of fat grafting in the treatment of PMPS based on the principle of regenerative medicine with a satisfactory response in terms of pain reduction and improvement of the quality of the treated tissues. Clinical questionnaires show that the cicatricial areas improve in terms of color, thickness, skin pliability, and surface irregularities. Regenerative effect is based also on the adoption of needles. The combined effect of fat grafting and needles determines a clinical full response.

Mesenchymal Stem Cells Beyond Regenerative Medicine

Mesenchymal stem cells (MSCs) are competent suitors of cellular therapy due to their therapeutic impact on tissue degeneration and immune-based pathologies. Additionally, their homing and immunomodulatory properties can be exploited in cancer malignancies to transport pharmacological entities, produce anti-neoplastic agents, or induce anti-tumor immunity. Herein, we create a portfolio for MSC properties, showcasing their distinct multiple therapeutic utilities and successes/challenges thereof in both animal studies and clinical trials. We further highlight the promising potential of MSCs not only in cancer management but also in instigating tumor-specific immunity - i.e., cancer vaccination. Finally, we reflect on the possible reasons impeding the clinical advancement of MSC-based cancer vaccines to assist in contriving novel methodologies from which a therapeutic milestone might emanate.

Autologous adipose tissue grafting for the management of the painful scar

BACKGROUND AIMS

There is currently no definitive treatment for the painful scar. Autologous adipose tissue grafting (AATG) as a treatment option for scars has become increasingly popular and there is now an abundance of evidence in the literature that supports its application. Some studies suggest that human adipose tissue is a rich source of multipotent mesenchymal stromal cells. To our knowledge, there is currently no systematic literature review to date that examines the effectiveness of AATG for reducing pain in scars. Our novel systematic review aims to examine clinical studies on the use of AATG in the treatment of the painful scar.

METHODS

A literature search was performed using the following databases: PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Medline, Cochrane library and Embase. The following key words and search terms were used: adipose stem cells, scar, pain, autologous fat grafting, scar management and neuropathic pain. Human interventional studies using autologous adipose tissue grafting for the treatment of painful scars including case series, case-control, cohort studies and randomized controlled trials were reviewed.

RESULTS

A total of 387 studies were found and 18 studies from January 1990 to January 2019 were identified as relevant for the purpose of this systematic review. Two studies were evidence level V, seven were evidence level IV, six were evidence level III, two were evidence level II and one was level I. A total of 337 scars were assessed in 288 patients for improvement in pain after scar treatment using adipose tissue grafting. An improvement in the analgesic effect was recorded in 12 of the 18 studies with adipose tissue grafting. A total of 233 of the 288 treated subjects responded with reduction in pain, whereas the rest did not. We carried out a pooled analysis of the studies and observed an odds ratio of 3.94 (P = 0.00001) when comparing pain reduction to no change in pain.

CONCLUSIONS

We conclude that AATG is a promising and safe modality for the treatment of the painful scar. There is an abundance of low-level evidence to support its use as an alternative treatment but there is a lack of high-level evidence at present to support its standard use. Future long-term randomized controlled trials with analgesic scores as the primary outcome measures are required to assess long-term efficacy.

Mesenchymal stem cells inhibit T-cell function through conserved induction of cellular stress

The physiological role of mesenchymal stem cells (MSCs) is to provide a source of cells to replace mesenchymal-derivatives in stromal tissues with high cell turnover or following stromal tissue damage to elicit repair. Human MSCs have been shown to suppress in vitro T-cell responses via a number of mechanisms including indoleamine 2,3-dioxygenase (IDO). This immunomodulatory capacity is likely to be related to their in vivo function in tissue repair where local, transient suppression of immune responses would benefit differentiation. Further understanding of the impact of locally modulated immune responses by MSCs is hampered by evidence that IDO is not produced or utilized by mouse MSCs. In this study, we demonstrate that IDO-mediated tryptophan starvation triggered by human MSCs inhibits T-cell activation and proliferation through induction of cellular stress. Significantly, we show that despite utilizing different means, immunomodulation of murine T-cells also involves cellular stress and thus is a common strategy of immunoregulation conserved between mouse and humans.

Mesenchymal Stem Cells in Systemic Sclerosis: Allogenic or Autologous Approaches for Therapeutic Use?

Systemic sclerosis (SSc) is a rare autoimmune disease, which is potentially lethal. The physiopathology of the disease is still incompletely elucidated although the role of fibroblasts, endothelial cells (ECs), immune cells. and the environment (i.e., oxidative stress) has been demonstrated. This is an intractable disease with an urgent need to provide better therapeutic options to patients. Mesenchymal stem cells (MSCs) represent a promising therapeutic approach thanks to the number of trophic and pleiotropic properties they exert. Among these, MSCs display anti-fibrotic, angiogenic, and immunomodulatory capacities that might be of interest in the treatment of SSc by acting on different processes that are dysregulated in the disease. In the recent years, the therapeutic effectiveness of MSCs has been demonstrated in different preclinical animal models and is being investigated in phase I clinical trials. Both allogenic and autologous transplantation of MSCs isolated from bone marrow or adipose tissue is being evaluated. The rationale for using allogenic MSCs in SSc, as well as in other autoimmune diseases, is based on the possibility that autologous MSCs might be altered in these diseases. In SSc, reports from the literature are controversial. Nevertheless, the role of the oxidative environment and of the crosstalk with neighboring cells (fibroblasts and ECs) on the functional properties of MSCs has been reported. Here, we review the preclinical and clinical data reporting the interest of MSC-based treatment in SSc and question the use of autologous or allogeneic MSCs in perspective of clinical applications.

Human adipose tissue-derived stromal cells act as functional pericytes in mice and suppress high-glucose-induced proinflammatory activation of bovine retinal endothelial cells

AIMS/HYPOTHESIS

The immunomodulatory capacity of adipose tissue-derived stromal cells (ASCs) is relevant for next-generation cell therapies that aim to reverse tissue dysfunction such as that caused by diabetes. Pericyte dropout from retinal capillaries underlies diabetic retinopathy and the subsequent aberrant angiogenesis.

METHODS

We investigated the pericytic function of ASCs after intravitreal injection of ASCs in mice with retinopathy of prematurity as a model for clinical diabetic retinopathy. In addition, ASCs influence their environment by paracrine signalling. For this, we assessed the immunomodulatory capacity of conditioned medium from cultured ASCs (ASC-Cme) on high glucose (HG)-stimulated bovine retinal endothelial cells (BRECs).

RESULTS

ASCs augmented and stabilised retinal angiogenesis and co-localised with capillaries at a pericyte-specific position. This indicates that cultured ASCs exert juxtacrine signalling in retinal microvessels. ASC-Cme alleviated HG-induced oxidative stress and its subsequent upregulation of downstream targets in an NF-κB dependent fashion in cultured BRECs. Functionally, monocyte adhesion to the monolayers of activated BRECs was also decreased by treatment with ASC-Cme and correlated with a decline in expression of adhesion-related genes such as SELE, ICAM1 and VCAM1.

CONCLUSIONS/INTERPRETATION

The ability of ASC-Cme to immunomodulate HG-challenged BRECs is related to the length of time for which ASCs were preconditioned in HG medium. Conditioned medium from ASCs that had been chronically exposed to HG medium was able to normalise the HG-challenged BRECs to normal glucose levels. In contrast, conditioned medium from ASCs that had been exposed to HG medium for a shorter time did not have this effect. Our results show that the manner of HG preconditioning of ASCs dictates their immunoregulatory properties and thus the potential outcome of treatment of diabetic retinopathy.

Intrastriatal transplantation of stem cells from human exfoliated deciduous teeth reduces motor defects in Parkinsonian rats

BACKGROUND

This study explored the neural differentiation and therapeutic effects of stem cells from human exfoliated deciduous teeth (SHED) in a rat model of Parkinson's disease (PD).

METHODS

The SHED were isolated from fresh dental pulp and were induced to differentiate to neurons and dopamine neurons by inhibiting similar mothers against dpp (SMAD) signaling with Noggin and increase conversion of dopamine neurons from SHED with CHIR99021, Sonic Hedgehog (SHH) and FGF8 in vitro. The neural-primed SHED were transplanted to the striatum of 6-hydroxydopamine (6-OHDA)-induced PD rats to evaluate their neural differentiation and functions in vivo.

RESULTS

These SHED were efficiently differentiated to neurons (62.7%) and dopamine neurons (42.3%) through a newly developed method. After transplantation, the neural-induced SHED significantly improved recovery of the motor deficits of the PD rats. The grafted SHED were differentiated into neurons (61%), including dopamine neurons (22.3%), and integrated into the host rat brain by forming synaptic connections. Patch clamp analysis showed that neurons derived from grafted SHED have the same membrane potential profile as dopamine neurons, indicating these cells are dopamine neuron-like cells. The potential molecular mechanism of SHED transplantation in alleviating motor deficits of the rats is likely to be mediated by neuronal replacement and immune-modulation as we detected the transplanted dopamine neurons and released immune cytokines from SHED.

CONCLUSION

Using neural-primed SHED to treat PD showed significant restorations of motor deficits in 6-OHDA-induced rats. These observations provide further evidence that SHED can be used for cell-based therapy of PD.

Functional recovery upon human dental pulp stem cell transplantation in a diabetic neuropathy rat model

Diabetic neuropathy (DN) is among the most debilitating complications of diabetes. Here, we investigated the effects of human dental pulp stem cell (DPSC) transplantation in Streptozotocin (STZ)-induced neuropathic rats. Six weeks after STZ injection, DPSCs were transplanted through two routes, intravenous (IV) or intramuscular (IM), in single or two repeat doses. Two weeks after transplantation, a significant improvement in hyperalgesia, grip-strength, motor coordination and nerve conduction velocity was observed in comparison with controls. A rapid improvement in neuropathic symptoms was observed for a single dose of DPSC IV; however, repeat dose of DPSC IV did not bring about added improvement. A single dose of DPSC IM showed steady improvement, and further recovery continued upon repeat IM administration. DPSC single dose IV showed greater improvement than DPSC single dose IM, but IM transplantation brought about better improvement in body weight. A marked reduction in tumor necrosis factor (TNF) α and C-reactive protein (CRP) levels was observed in the blood plasma for all treated groups, as compared with controls. With respect to inflammatory cytokines, repeat dose of DPSC IM showed further improvement, suggesting that a repeat dose is required to maintain the improved inflammatory state. Gene expression of inflammatory markers in liver confirmed amelioration in inflammation. Arachidonic acid level was unaffected by IV DPSC transplantation but showed noticeable increase through IM administration of a repeat dose. These results suggest that DPSC transplantation through both routes and dosage was beneficial for the retrieval of neuropathic parameters of DN; transplantation via the IM route with repeat dose was the most effective.

Cardiac Cell-Based Therapy: Cell Types and Mechanisms of Actions

Over the past decade, the concept that the heart could undergo cardiac regeneration has rapidly evolved. Studies have indicated that numerous sites in the body harbor stem or progenitor cells, prompting clinical trials of these potential therapeutic cell-based approaches. Most notable are the series of trials utilizing either skeletal myoblasts or autologous whole bone marrow. More recently the quest has focused on specific bone marrow constituents, most notably the mesenchymal stem cell, which has several unique advantages including immunoprivilege, immunosuppression, and the ability to home to areas of tissue injury. Most recently, cells have been identified within the heart itself that are capable of self-replication and differentiation. The discovery of cardiac stem cells offers not only a potential therapeutic approach but also provides a plausible target for endogenous activation as a therapeutic strategy. Together the new insights obtained from studies of cell-based cardiac therapy have ushered in new biological paradigms and enormous potential for novel therapeutic strategies for cardiac disease.

Immunologic properties of differentiated and undifferentiated mesenchymal stem cells derived from umbilical cord blood

The expression of immunogenic markers after differentiation of umbilical cord blood (UCB)-derived mesenchymal stem cells (MSC) has been poorly investigated and requires extensive in vitro and in vivo testing for clinical application. The expression of human leukocyte antigen (HLA) classes on UCB-derived MSC was tested by Fluorescence-activated cell sorting analysis and immunocytochemical staining. The undifferentiated MSC were moderately positive for HLA-ABC, but almost completely negative for HLA-DR. The MSC differentiated to chondrocytes expressed neither HLA-ABC nor HLA-DR. The proliferation of MSC was not significantly affected by the allogeneic lymphocytes stimulated with concanavalin A. The responder lymphocytes showed no significant decrease in proliferation in the presence of the MSC, but the apoptosis rate of the lymphocytes was increased in the presence of MSC. Taken together, these findings indicate that UCB-derived MSC differentiated to chondrocytes expressed less HLA class I and no class II antigens. The MSC showed an immunomodulatory effect on the proliferation and apoptosis of allogeneic lymphocytes. These data suggest that the differentiated and undifferentiated allogeneic MSC derived from umbilical cord blood can be a useful candidate for allogeneic cell therapy and transplantation without a major risk of rejection.

Concise Review: Fat and Furious: Harnessing the Full Potential of Adipose-Derived Stromal Vascular Fraction

Due to their capacity to self-renew, proliferate and generate multi-lineage cells, adult-derived stem cells offer great potential for use in regenerative therapies to stop and/or reverse degenerative diseases such as diabetes, heart failure, Alzheimer's disease and others. However, these subsets of cells can be isolated from different niches, each with differing potential for therapeutic applications. The stromal vascular fraction (SVF), a stem cell enriched and adipose-derived cell population, has garnered interest as a therapeutic in regenerative medicine due to its ability to secrete paracrine factors that accelerate endogenous repair, ease of accessibility and lack of identified major adverse effects. Thus, one can easily understand the rush to employ adipose-derived SVF to treat human disease. Perhaps faster than any other cell preparation, SVF is making its way to clinics worldwide, while critical preclinical research needed to establish SVF safety, efficacy and optimal, standardized clinical procedures are underway. Here, we will provide an overview of the current knowledge driving this phenomenon, its regulatory issues and existing studies, and propose potential unmapped applications. Stem Cells Translational Medicine 2017;6:1096-1108.

Human and feline adipose-derived mesenchymal stem cells have comparable phenotype, immunomodulatory functions, and transcriptome

Background

Adipose-derived mesenchymal stem cells (ASCs) are a promising cell therapy to treat inflammatory and immune-mediated diseases. Development of appropriate pre-clinical animal models is critical to determine safety and attain early efficacy data for the most promising therapeutic candidates. Naturally occurring diseases in cats already serve as valuable models to inform human clinical trials in oncologic, cardiovascular, and genetic diseases. The objective of this study was to complete a comprehensive side-by-side comparison of human and feline ASCs, with an emphasis on their immunomodulatory capacity and transcriptome.

Methods

Human and feline ASCs were evaluated for phenotype, immunomodulatory profile, and transcriptome. Additionally, transwells were used to determine the role of cell-cell contact in ASC-mediated inhibition of lymphocyte proliferation in both humans and cats.

Results

Similar to human ASCs, feline ASCs were highly proliferative at low passages and fit the minimal criteria of multipotent stem cells including a compatible surface protein phenotype, osteogenic capacity, and normal karyotype. Like ASCs from all species, feline ASCs inhibited mitogen-activated lymphocyte proliferation in vitro, with or without direct ASC-lymphocyte contact. Feline ASCs mimic human ASCs in their mediator secretion pattern, including prostaglandin E2, indoleamine 2,3 dioxygenase, transforming growth factor beta, and interleukin-6, all augmented by interferon gamma secretion by lymphocytes. The transcriptome of three unactivated feline ASC lines were highly similar. Functional analysis of the most highly expressed genes highlighted processes including: 1) the regulation of apoptosis; 2) cell adhesion; 3) response to oxidative stress; and 4) regulation of cell differentiation. Finally, feline ASCs had a similar gene expression profile to noninduced human ASCs.

Conclusions

Findings suggest that feline ASCs modulate lymphocyte proliferation using soluble mediators that mirror the human ASC secretion pattern. Uninduced feline ASCs have similar gene expression profiles to uninduced human ASCs, as revealed by transcriptome analysis. These data will help inform clinical trials using cats with naturally occurring diseases as surrogate models for human clinical trials in the regenerative medicine arena.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0528-z) contains supplementary material, which is available to authorized users.

Cell culture density affects the stemness gene expression of adipose tissue-derived mesenchymal stem cells

The results of clinical trials using mesenchymal stem cells (MSCs) are controversial due to the heterogeneity of human MSCs and differences in culture conditions. In this regard, it is important to identify gene expression patterns according to culture conditions, and to determine how the cells are expanded and when they should be clinically used. In the current study, stemness gene expression was investigated in adipose tissue-derived MSCs (AT-MSCs) harvested following culture at different densities. AT-MSCs were plated at a density of 200 or 5,000 cells/cm². After 7 days of culture, stemness gene expression was examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. The proliferation rate of AT-MSCs harvested at a low density (~50% confluent) was higher than that of AT-MSCs harvested at a high density (~90% confluent). Although there were differences in the expression levels of stemness gene, such as octamer-binding transcription factor 4, nanog homeobox (Nanog), SRY-box 2, Kruppel like factor 4, v-myc avian myelocytomatosis viral oncogene homolog (c-Myc), and lin-28 homolog A, in the AT-MSCs obtained from different donors, RT-qPCR analysis demonstrated differential gene expression patterns according to the cell culture density. Expression levels of stemness genes, particularly Nanog and c-Myc, were upregulated in AT-MSCs harvested at a low density (~50% confluent) in comparison to AT-MSCs from the same donor harvested at a high density (~90% confluent). These results imply that culture conditions, such as the cell density at harvesting, modulate the stemness gene expression and proliferation of MSCs.

Skeletal Muscle-Derived Stem/Progenitor Cells: A Potential Strategy for the Treatment of Acute Kidney Injury

Skeletal muscle-derived stem/progenitor cells (MDSPCs) have been thoroughly investigated and already used in preclinical studies. However, therapeutic potential of MDSPCs isolated using preplate isolation technique for acute kidney injury (AKI) has not been evaluated. We aimed to characterize rat MDSPCs, compare them with bone marrow mesenchymal stem cells (BM-MSCs), and evaluate the feasibility of MDSPCs therapy for gentamicin-induced AKI in rats. We have isolated and characterized rat MDSPCs and BM-MSCs. Characteristics of rat BM-MSCs and MDSPCs were assessed by population doubling time, flow cytometry, immunofluorescence staining, RT-PCR, and multipotent differentiation capacity. Gentamicin-induced AKI model in rat was used to examine MDSPCs therapeutic effect. Physiological and histological kidney parameters were determined. MDSPCs exhibited similar immunophenotype, stem cell gene expression, and multilineage differentiation capacities as BM-MSCs, but they demonstrated higher proliferation rate. Single intravenous MDSPCs injection accelerated functional and morphological kidney recovery, as reflected by significantly lower serum creatinine levels, renal injury score, higher urinary creatinine, and GFR levels. PKH-26-labeled MDSPCs were identified within renal cortex 1 and 2 weeks after cell administration, indicating MDSPCs capacity to migrate and populate renal tissue. In conclusion, MDSPCs are capable of mediating functional and histological kidney recovery and can be considered as potential strategy for AKI treatment.

Adipose-derived mesenchymal stromal cells modulate tendon fibroblast responses to macrophage-induced inflammation in vitro

Introduction

Macrophage-driven inflammation is a key feature of the early period following tendon repair, but excessive inflammation has been associated with poor clinical outcomes. Modulation of the inflammatory environment using molecular or cellular treatments may provide a means to enhance tendon healing.

Methods

To examine the effect of pro-inflammatory cytokines secreted by macrophages on tendon fibroblasts (TF), we established in vitro models of cytokine and macrophage-induced inflammation. Gene expression, protein expression, and cell viability assays were used to examine TF responses. In an effort to reduce the negative effects of inflammatory cytokines on TFs, adipose-derived mesenchymal stromal cells (ASCs) were incorporated into the model and their ability to modulate inflammation was investigated.

Results

The inflammatory cytokine interleukin 1 beta (IL-1β) and macrophages of varying phenotypes induced up-regulation of pro-inflammatory factors and matrix degradation factors and down-regulation of factors related to extracellular matrix formation by TFs in culture. ASCs did not suppress these presumably negative effects induced by IL-1β. However, ASC co-culture with M1 (pro-inflammatory) macrophages successfully suppressed the effects of M1 macrophages on TFs by inducing a phenotypic switch from a pro-inflammatory macrophage phenotype to an anti-inflammatory macrophage phenotype, thus resulting in exposure of TFs to lower levels of pro-inflammatory cytokines (e.g., IL-1β, tumor necrosis factor alpha (TNFα)).

Conclusions

These findings suggest that IL-1β and M1 macrophages are detrimental to tendon healing and that ASC-mediated modulation of the post-operative inflammatory response may be beneficial for tendon healing.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0059-4) contains supplementary material, which is available to authorized users.

Prevention of acute liver allograft rejection by IL-10-engineered mesenchymal stem cells

Hepatic allograft rejection remains a challenging problem, with acute rejection episode as the major barrier for long-term survival in liver transplant recipients. To explore a strategy to prevent allograft rejection, we hypothesized that mesenchymal stem cells (MSCs) genetically engineered with interleukin-10 (IL-10) could produce beneficial effects on orthotopic liver transplantation (OLT) in the experimental rat model. Syngeneic MSCs transduced with IL-10 were delivered via the right jugular vein 30 min post-orthotopic transplantation in the rat model. To evaluate liver morphology and measure cytokine concentration, the blood and liver samples from each animal group were collected at different time-points (3, 5 and 7 days) post-transplantation. The mean survival time of the rats treated with MSCs-IL-10 was shown to be much longer than those treated with saline. According to Banff scheme grading, the saline group scores increased significantly compared with those in the MSCs-IL-10 group. Retinoid acid receptor-related orphan receptor gamma t (RORγt) expression was more increased in the saline group compared to those in the MSCs-IL-10 group in a time-dependent manner; forkhead box protein 3 (FoxP3) expression also decreased significantly in the saline group compared with those in the MSCs-IL-10 group in a time-dependent manner. The expression of cytokines [IL-17, IL-23, IL-6, interferon (IFN)-γ and tumour necrosis factor (TNF)-α] in the saline groups increased significantly compared with the time-point-matched MSCs-IL-10 group, whereas cytokine expression of (IL-10, TGF-β1) was deceased markedly compared to that in the MSCs-IL-10 group. These results suggest a potential role for IL-10-engineered MSC therapy to overcome clinical liver transplantation rejection.

Autologous fat graft in postmastectomy pain syndrome following breast conservative surgery and radiotherapy

BACKGROUND

Breast cancer is the most common cancer in women worldwide, affecting one in eight women. Breast-conserving surgery (BCS) has become a well-established alternative to mastectomy in the treatment of breast cancer, providing a less invasive treatment. Just as life expectancy after breast cancer has improved, so has morbidity increased. One of the most relevant and debilitating consequences of oncological breast surgery is postmastectomy pain syndrome (PMPS). Our results published in 2011 on the treatment of PMPS in patients who had undergone mastectomy and radiotherapy and our experience in scar treatment with fat grafts were the theoretical bases for this prospective study.

METHODS

From April 2011 to April 2012 a total of 96 patients, who had undergone lumpectomy and radiation therapy, with the diagnosis of PMPS were considered for fat grafts. We performed autologous fat grafting in 59 patients (study group), whereas 37 patients did not receive any further surgical procedure (control group). Pain assessment was performed using the visual analog scale (VAS) before and after treatment in the treated group and in the control group at the first visit and the control visit, with a mean follow-up of 10 months. Results were analyzed using the Wilcoxon rank sum test.

RESULTS

Four patients were lost to follow-up (two patients in the control group and two patients in the treated group). A significant VAS pain decrease was detected in patients treated with autologous fat grafting (3.1 point reduction, p ≤ 0.005).

CONCLUSION

Because of the safety, efficacy, and optimal tolerability of the procedure, we believe that fat grafting can be considered useful in treating PMPS in patients who have undergone BCS and radiotherapy.

LEVEL OF EVIDENCE III

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.

Human application of ex vivo expanded umbilical cord-derived mesenchymal stem cells: enhance hematopoiesis after cord blood transplantation

Delayed hematopoietic reconstitution after cord blood (CB) transplantation (CBT) needs to be overcome. Bone marrow-derived mesenchymal stem cells (BMMSCs) have been found to enhance engraftment after hematopoietic stem cell transplantation. However, getting BMMSCs involves an invasive procedure. In this study, umbilical cord-derived mesenchymal stem cells (UCMSCs) were isolated from Wharton's jelly and cryopreserved in the UCMSCs bank. Compared with BMMSCs, we found that UCMSCs had superior proliferative potential. We found that NOD/SCID mice cotransplanted with CB and UCMSCs demonstrated significant human CD45(+) cell engraftment compared with those transplanted with CB alone. Then, 20 patients with high-risk leukemia were prospectively randomized to either receive cotransplantation of CB and ex vivo expanded banked UCMSCs or to receive CBT alone. No serious adverse events were observed in the patients receiving UCMSC infusion. The time to undergo neutrophil engraftment and platelet engraftment was significantly shorter in the eight patients receiving cotransplantation than that in the 12 patients receiving CBT alone (p=0.003 and p=0.004, respectively). Thus, application of ex vivo expanded banked UCMSCs in humans appears to be feasible and safe. UCMSCs can enhance engraftment after CBT, but further studies are warranted.

Isolation, characterization, differentiation, and application of adipose-derived stem cells

While bone marrow-derived mesenchymal stem cells are known and have been investigated for a long time, mesenchymal stem cells derived from the adipose tissue were identified as such by Zuk et al. in 2001. However, as subcutaneous fat tissue is a rich source which is much more easily accessible than bone marrow and thus can be reached by less invasive procedures, adipose-derived stem cells have moved into the research spotlight over the last 8 years.Isolation of stromal cell fractions involves centrifugation, digestion, and filtration, resulting in an adherent cell population containing mesenchymal stem cells; these can be subdivided by cell sorting and cultured under common conditions.They seem to have comparable properties to bone marrow-derived mesenchymal stem cells in their differentiation abilities as well as a favorable angiogenic and anti-inflammatory cytokine secretion profile and therefore have become widely used in tissue engineering and clinical regenerative medicine.

The role of sacrolumbar fat grafting in the treatment of spinal fusion instrumentation-related chronic low back pain: a preliminary report

STUDY DESIGN

A report of 2 cases.

OBJECTIVE

The purpose of this article is to report 2 preliminary cases with instrumentation-related chronic low back pain (CLBP) successfully treated with fat graft in the sacrolumbar region.

SUMMARY OF BACKGROUND DATA

Patients undergoing successful spinal fusion surgery may experience new or recurrent CLBP. Instrumentation-related soft-tissue irritation is a well-known etiology of this frustrating condition. Treatment options vary from conservative treatment till instrumentation removal, with no consensus on their efficacy.

METHODS

A 32-year-old patient and a 37-year-old patient with instrumentation-related debilitating CLBP visual analogue scale score 7 and 10, respectively, underwent 1 session of fat grafting in the sacrolumbar region.

RESULTS

At 9-month and 6-month follow-ups, both patients reported a substantial pain relief, a considerable improvement in daily quality of life and satisfaction for less implant palpability and visibility.

CONCLUSION

The encouraging results of these preliminary cases may open new horizons for a multidisciplinary approach in treating instrumentation-related CLBP. Fat grafting may represent a valid and minimal invasive option to be taken into account when established therapeutic options fail. Further experience with longer follow-up is needed to confirm our findings.

LEVEL OF EVIDENCE

5.

Gene expression profiles of human adipose tissue-derived mesenchymal stem cells are modified by cell culture density

Previous studies conducted cell expansion ex vivo using low initial plating densities for optimal expansion and subsequent differentiation of mesenchymal stem cells (MSCs). However, MSC populations are heterogeneous and culture conditions can affect the characteristics of MSCs. In this study, differences in gene expression profiles of adipose tissue (AT)-derived MSCs were examined after harvesting cells cultured at different densities. AT-MSCs from three different donors were plated at a density of 200 or 5,000 cells/cm². After 7 days in culture, detailed gene expression profiles were investigated using a DNA chip microarray, and subsequently validated using a reverse transcription polymerase chain reaction (RT-PCR) analysis. Gene expression profiles were influenced primarily by the level of cell confluence at harvest. In MSCs harvested at ∼90% confluence, 177 genes were up-regulated and 102 genes down-regulated relative to cells harvested at ∼50% confluence (P<0.05, FC>2). Proliferation-related genes were highly expressed in MSCs harvested at low density, while genes that were highly expressed in MSCs harvested at high density (∼90% confluent) were linked to immunity and defense, cell communication, signal transduction and cell motility. Several cytokine, chemokine and growth factor genes involved in immunosuppression, migration, and reconstitution of damaged tissues were up-regulated in MSCs harvested at high density compared with MSCs harvested at low density. These results imply that cell density at harvest is a critical factor for modulating the specific gene-expression patterns of heterogeneous MSCs.

Autologous transplantation of GDNF-expressing mesenchymal stem cells protects against MPTP-induced damage in cynomolgus monkeys

Glial cell-derived neurotrophic factor (GDNF) has shown beneficial effects in models of Parkinson's disease. The mild results observed in the double-blind clinical trial by intraputamenal infusion of recombinant GDNF proteins warrant a search for alternative delivery methods. In this study, we investigated the function of autologous mesenchymal stem cells (MSCs) expressing GDNF (GDNF-MSCs) for protection against MPTP-induced injury in cynomolgus monkeys. MSCs were obtained from the bone marrow of individual monkeys and gene-modified to express GDNF. Following unilateral engraftment of GDNF-MSCs into the striatum and substantia nigra, the animals were challenged with MPTP to induce a stable systemic Parkinsonian state. The motor functions were spared in the contralateral limbs of monkeys receiving GDNF-MSCs, but not in those receiving MSCs alone. In the striatum of the grafted hemisphere, dopamine levels were higher and dopamine uptake was enhanced. The results suggest that autologous MSCs may be a safe vehicle to deliver GDNF for enhancing nigro-striatum functions.

Immunomodulatory effects of adipose-derived stem cells: fact or fiction?

Adipose-derived stromal cells (ASCs) are often referred to as adipose-derived stem cells due to their potential to undergo multilineage differentiation. Their promising role in tissue engineering and ability to modulate the immune system are the focus of extensive research. A number of clinical trials using ASCs are currently underway to better understand the role of such cell niche in enhancing or suppressing the immune response. If governable, such immunoregulatory role would find application in several conditions in which an immune response is present (i.e., autoimmune conditions) or feared (i.e., solid organ or reconstructive transplantation). Although allogeneic ASCs have been shown to prevent acute GvHD in both preclinical and clinical studies, their potential warrants further investigation. Well-designed and standardized clinical trials are necessary to prove the role of ASCs in the treatment of immune disorders or prevention of tissue rejection. In this paper we analyze the current literature on the role of ASCs in immunomodulation in vitro and in vivo and discuss their potential in regulating the immune system in the context of transplantation.

Premature lung aging and cellular senescence in the pathogenesis of idiopathic pulmonary fibrosis and COPD/emphysema

Different anatomic and physiological changes occur in the lung of aging people that can affect pulmonary functions, and different pulmonary diseases, including deadly diseases such as chronic obstructive pulmonary disease (COPD)/emphysema and idiopathic pulmonary fibrosis (IPF), can be related to an acceleration of the aging process. The individual genetic background, as well as exposure to a variety of toxic substances (cigarette smoke in primis) can contribute significantly to accelerating pulmonary senescence. Premature aging can impair lung function by different ways: by interfering specifically with tissue repair mechanisms after damage, thus perturbing the correct crosstalk between mesenchymal and epithelial components; by inducing systemic and/or local alteration of the immune system, thus impairing the complex mechanisms of lung defense against infections; and by stimulating a local and/or systemic inflammatory condition (inflammaging). According to recently proposed pathogenic models in COPD and IPF, premature cellular senescence likely affects distinct progenitors cells (mesenchymal stem cells in COPD, alveolar epithelial precursors in IPF), leading to stem cell exhaustion. In this review, the large amount of data supporting this pathogenic view are discussed, with emphasis on the possible molecular and cellular mechanisms leading to the severe parenchymal remodeling that characterizes, in different ways, these deadly diseases.

Adipose tissue-derived stem cells in clinical applications

INTRODUCTION

In the past decade human adipose tissue has been identified as a source of multipotent stem cells. Adipose tissue derived stem cells (ASCs) are characterised by immunosuppressive properties and low immunogenicity. Therefore, they can be used in regenerative medicine, as well as applied to induce graft tolerance or prevent autoimmunity. ASCs can be easily harvested with low morbidity, which is their main advantage over mesenchymal stem cells (MSCs) derived from other sources.

AREAS COVERED

The review focuses on reported clinical applications of ASCs and discusses technical approaches of their isolation and processing. The differences in phenotype and differentiation preferences between ASCs and other MSCs that may affect the choice of a particular cell type for the future therapy are also described.

EXPERT OPINION

ASCs seem to be the perfect tool for regenerative medicine and immunosuppressive cellular therapies. Nevertheless, there are some tasks that should be addressed by the future studies: i) ASCs require better characterisation; a set of markers determining ASCs should be clearly defined; ii) there is need for more studies on safety of reconstructive therapies with ASCs in cancer patients (e.g., after mastectomy); iii) release criteria should be determined for freshly isolated and ex vivo expanded ASCs designed for clinical applications.

IL-6 is produced by adipose-derived stromal cells and promotes osteogenesis

Although Toll-like receptors (TLRs) have been implicated in the regulation of stem cell functions, their role in osteogenic differentiation of adipose-derived stromal cells (ASCs) has not been reported. We found that ASCs express a restricted subset of TLRs, including TLR1-TLR5, and that TLR agonists such as Pam3CSK4 (TLR1/2 agonist), polyinosinic:polycytidylic acid (TLR3 agonist), lipopolysaccharide (TLR4 agonist), and flagellin (TLR5 agonist), but not R848 (TLR7/8 agonist), consistently induced osteogenic differentiation in murine-derived ASCs, which coincided with the TLR expression pattern of ASCs. Cytokine expression profiles induced by TLR agonists and results from subsequent functional assays indicated that interleukin-6 (IL-6) together with soluble IL-6 receptor (sIL-6R) enhanced osteogenic differentiation of ASCs by activating STAT3. Small interfering RNA (siRNA)-mediated STAT3-silencing blunted osteogenesis and the expression of osteogenic markers, whereas STAT3 overexpression resulted in an increase in osteogenesis. Consistently, STAT3 inhibitor treatment reduced osteogenesis, STAT3 phosphorylation, and expression of osteogenic markers including osterix. Chromatin immunoprecipitation (ChIP) assays indicated that STAT3 binding to the STAT3-binding sites on the osterix promoter increased during IL-6-stimulated osteogenesis. Our results thus establish TLRs as novel regulators of ASCs which signal through IL-6/STAT3 pathway and induce osterix expression as a part of the osteogenesis.

Mutual effect of subcutaneously transplanted human adipose-derived stem cells and pancreatic islets within fibrin gel

While subcutaneous tissue has been proposed as a potential site for pancreatic islet transplantation, concern remains that the microvasculature of subcutaneous tissue is too poor to support transplanted islets. In an effort to overcome this limitation, we evaluated whether fibrin gel with human adipose-derived stem cells (hADSCs) and rat pancreatic islets could cure diabetes mellitus when transplanted into the subcutaneous space of diabetic mice. Subcutaneously co-transplanted islets and hADSCs showed normalization of the diabetic recipient's blood glucose levels. The result was enhanced by co-treatment of fibroblast growth factor-2 (FGF2) in the fibrin gel. The hADSCs enhanced islet viability after transplantation by secreting various growth factors that can protect islets from hypoxic damage. Afterward, hADSCs could maintain islet viability by recruiting new microvasculature nearby the transplanted islets via overexpression of vascular endothelial growth factor (VEGF). The hADSCs did not directly differentiate into endothelial cells (no detection of biomarkers of human endothelial cells), but showed evidence of differentiation toward insulin-secreting cells (detection of human insulin). Mice receiving islet transplantation alone did not become normoglycemic. Collectively, co-transplantation of fibrin gel with islets and hADSCs will expand the indications for islet transplant therapy and the potential clinical application of cell-based therapy.

Human bone marrow-derived mesenchymal stem cell gene expression patterns vary with culture conditions

Background

Because of the heterogeneity of human mesenchymal stem cells (MSCs), methods for cell expansion in culture and the effects on gene expression are critical factors that need to be standardized for preparing MSCs. We investigated gene expression patterns of MSCs with different seeding densities and culture times.

Methods

Bone marrow-derived MSCs were plated at densities from 200 cells/cm² to 5,000 cells/cm², and the gene expression patterns were evaluated over time using a reverse-transcription polymerase chain reaction assay.

Results

The mRNA levels of factors that play a critical role in cell migration and tissue regeneration, such as podocalyxin-like protein (PODXL), α4-integrin, α6-integrin, and leukemia inhibitory factor (LIF), were higher in MSCs plated at 200 cells/cm² than in MSCs plated at 5,000 cells/cm². The mRNA levels of these factors gradually increased for 10 days and then decreased by day 15 in culture. MSCs seeded at 200 cells/cm² that were cultured for 10 days expressed high levels of Oct-4 and Nanog. Indoleamine 2,3-dioxygenase, cyclooxygenase-1, and hepatocyte growth factor expression were upregulated in the presence of the proinflammatory cytokine interferon-γ in these cells.

Conclusion

We found differences in the gene expression patterns of MSCs under different culture conditions. MSCs from 10-day cultures seeded at a low density were efficiently expanded, expressed PODXL, α6-integrin, α4-integrin, and LIF, and maintained properties like stemness and immunomodulation. Therefore, ex vivo expansion of MSCs maintained for an adequate culture time after plating at low cell density can provide an effective regenerative medicinal strategy for cell therapies using MSCs.

Human adipose tissue-derived mesenchymal stem cells secrete functional neprilysin-bound exosomes

Alzheimer's disease (AD) is characterized by the accumulation of β-amyloid peptide (Aβ) in the brain because of an imbalance between Aβ production and clearance. Neprilysin (NEP) is the most important Aβ-degrading enzyme in the brain. Thus, researchers have explored virus-mediated NEP gene delivery. However, such strategies may entail unexpected risks, and thus exploration of a new possibility for NEP delivery is also required. Here, we show that human adipose tissue-derived mesenchymal stem cells (ADSCs) secrete exosomes carrying enzymatically active NEP. The NEP-specific activity level of 1 μg protein from ADSC-derived exosomes was equivalent to that of ~ 0.3 ng of recombinant human NEP. Of note, ADSC-derived exosomes were transferred into N2a cells, and were suggested to decrease both secreted and intracellular Aβ levels in the N2a cells. Importantly, these characteristics were more pronounced in ADSCs than bone marrow-derived mesenchymal stem cells, suggesting the therapeutic relevance of ADSC-derived exosomes for AD.

Effects of xenogeneic adipose-derived stem cell transplantation on acute-on-chronic liver failure

BACKGROUND

Adipose-derived stem cells (ADSCs) are particularly attractive in future clinical applications of stem cell-based therapy for acute-on-chronic liver failure (ACLF). This study was undertaken to evaluate the therapeutic potential of ADSCs on ACLF.

METHODS

ADSCs isolated from porcine fat tissue were expanded and labeled with BrdU. Rabbit models of ACLF were created by administration of D-Gal following CCl4-induced cirrhosis. One day after administration of D-Gal, rabbits of the ACLF/ADSCs group (n=15) were received ADSCs transplantation, while those in the ACLF/saline group (n=15) were treated with the same volume of saline. Biochemical parameters and histomorphological scoring were evaluated; the distribution and characteristics of transplanted ADSCs as well as the pathology of the liver were examined.

RESULTS

ADSCs transplantation improved the survival rate and the liver function of rabbits with ACLF. Biochemical parameters of the ACLF/ADSCs group were improved compared with those of the ACLF/saline group, and histomorphological scoring of the ACLF/ADSCs group was significantly lower than that of the ACLF/saline group. ADSCs were identified in the periportal region of the liver after cell transplantation.

CONCLUSION

Xenogenic ADSCs have therapeutic efficacy in the ACLF rabbit model.