Characterization and Safety Profile of a New Combined Advanced Therapeutic Medical Product Platelet Lysate-Based Fibrin Hydrogel for Mesenchymal Stromal Cell Local Delivery in Regenerative Medicine.

Adipose-derived mesenchymal stromal cells (ASC) transplant to recover the optimal tissue structure/function relationship is a promising strategy to regenerate tissue lesions. Because filling local tissue defects by injection alone is often challenging, designing adequate cell carriers with suitable characteristics is critical for in situ ASC delivery. The aim of this study was to optimize the generation phase of a platelet-lysate-based fibrin hydrogel (PLFH) as a proper carrier for in situ ASC implantation and (1) to investigate in vitro PLFH biomechanical properties, cell viability, proliferation and migration sustainability, and (2) to comprehensively assess the local in vivo PLFH/ASC safety profile (local tolerance, ASC fate, biodistribution and toxicity). We first defined the experimental conditions to enhance physicochemical properties and microscopic features of PLFH as an adequate ASC vehicle. When ASC were mixed with PLFH, in vitro assays exhibited hydrogel supporting cell migration, viability and proliferation. In vivo local subcutaneous and subgingival PLFH/ASC administration in nude mice allowed us to generate biosafety data, including biodegradability, tolerance, ASC fate and engraftment, and the absence of biodistribution and toxicity to non-target tissues. Our data strongly suggest that this novel combined ATMP for in situ administration is safe with an efficient local ASC engraftment, supporting the further development for human clinical cell therapy.

Periodontal Cell Therapy: A Systematic Review and Meta-analysis.

BACKGROUND: Periodontitis is a chronic inflammatory disease characterized by the loss of tooth-supporting tissues (or periodontium) leading to the formation of periodontal pocket then to tooth loss. Conventional therapies that involve tooth root debridement are still disappointing because they are more centered on periodontal repair than disease pathophysiology causes. The meta-analysis we present here focused on the results of experimental studies that investigated periodontal mesenchymal stromal cells (MSCs) therapy, a promising strategy to regenerate tissue, given to their immunomodulatory and trophic properties. METHODS: Using PubMed database and ICTRP search portal, 84 animal and 3 randomized human studies were analyzed. RESULTS: Overall, our results highlighted that MSCs grafting, regardless of their tissue origin, enhances periodontal regeneration. A defect morphology suitable for an initial clot stabilization increases the procedure efficacy, especially if cells are carried using a vehicle from natural origin. Nevertheless, methodological biases have been highlighted and still limit the translation to human with high prognosis and regulatory considerations. Besides, because only 2 randomized human trials demonstrated the efficacy of the procedure, further studies are needed to investigate periodontal regeneration procedures on experimental models closer to human pathophysiology. CONCLUSION: Although MSCs grafting in periodontal disease demonstrated therapeutic benefits in animal, it is critical to define more accurately protocols translatable to human and focus on the treatment of the pathology as a whole rather than on the restitution of the sole destroyed tissues.

Spatial and temporal structure of the clinical research based on mesenchymal stromal cells: A network analysis.

BACKGROUND AIMS: Using innovative tools derived from social network analysis, the aims of this study were (i) to decipher the spatial and temporal structure of the research centers network dedicated to the therapeutic uses of mesenchymal stromal cells (MSCs) and (ii) to measure the influence of fields of applications, cellular sources and industry funding on network topography. METHODS: From each trial using MSCs reported on ClinicalTrials.gov, all research centers were extracted. Networks were generated using Cytoscape 3.2.2, where each center was assimilated to a node, and one trial to an edge connecting two nodes. RESULTS: The analysis included 563 studies. An independent segregation was obvious between continents. Asian, South American and African centers were significantly more isolated than other centers. Isolated centers had fewer advanced phases (P <0.001), completed studies (P = 0.01) and industry-supported studies (P <0.001). Various thematic priorities among continents were identified: the cardiovascular, digestive and nervous system diseases were strongly studied by North America, Europe and Asia, respectively. The choice of cellular sources also affected the network topography; North America was primarily involved in bone-marrow-derived MSC research, whereas Europe and Asia dominated the use of adipose-derived MSCs. Industrial funding was the highest for North American centers (90.5%). CONCLUSIONS: Strengthening of international standards and statements with institutional, federal and industrial partners is necessary. More connections would facilitate the transfer of knowledge, sharing of resources, mobility of researchers and advancement of trials. Developing partnerships between industry and academic centers seems beneficial to the advancement of trials across different phases and would facilitate the translation of research discoveries.

Comparison between pediatric and adult adipose mesenchymal stromal cells.

BACKGROUND: Adipose-derived mesenchymalstromal cells (ASC) are currently tested in regenerative medicine to promote tissue reconstruction after injury. Regardingautologous purpose, the possible loss of therapeutic function and cell properties during aging have been questioned in adults. To date no reliable information is available concerning ASC from pediatric patients and a better knowledge is required for clinical applications. METHODS: Subcutaneous adipose tissue was collected from 27 donors (0-1 years old) and 50 donors (1-12 years old) and compared with adult ASC for in vitro characteristics. ASC were then tested in a mouse model of limb ischemia. RESULTS: Cells from the stromal vascular fraction (SVF) and subsequent cultured ASC were prepared. Only a greater amount in SVF cell number and ASC proliferative rate were found. Cell phenotype, colony formingunit-fibroblast (CFU-F) content, immunomodulation effect and adipogenic, osteoblastic and angiogenic potentials were not significantly different. In vivo, pediatric ASC induced an increase in microangiographic score in a mouse model of limb ischemia, even though improvement in vascular density was not significantly correlated to limb rescue. Finally messengerRNA (mRNA) analysis using a microarray approach identified that only 305 genes were differentially expressed (217 down- and 88 up-regulated) in pediatric versus adult ASC, confirming that ASC from both age groups shared very close intrinsic properties. CONCLUSION: This is the first study reporting a comparative analysis of ASC from a large number of donors and showing that their in vitro and in vivo properties were similar and maintained during aging.

Phase I trial: the use of autologous cultured adipose-derived stroma/stem cells to treat patients with non-revascularizable critical limb ischemia.

BACKGROUND AIMS: Non-revascularizable critical limb ischemia (CLI) is the most severe stage of peripheral arterial disease, with no therapeutic option. Extensive preclinical studies have demonstrated that adipose-derived stroma cell (ASC) transplantation strongly improves revascularization and tissue perfusion in ischemic limbs. This study, named ACellDREAM, is the first phase I trial to evaluate the feasibility and safety of intramuscular injections of autologous ASC in non-revascularizable CLI patients. METHODS: Seven patients were consecutively enrolled, on the basis of the following criteria: (i) lower-limb rest pain or ulcer; (ii) ankle systolic oxygen pressure <50 or 70 mm Hg for non-diabetic and diabetic patients, respectively, or first-toe systolic oxygen pressure <30 mm Hg or 50 mm Hg for non-diabetic and diabetic patients, respectively; (iii) not suitable for revascularization. ASCs from abdominal fat were grown for 2 weeks and were then characterized. RESULTS: More than 200 million cells were obtained, with almost total homogeneity and no karyotype abnormality. The expressions of stemness markers Oct4 and Nanog were very low, whereas expression of telomerase was undetectable in human ASCs compared with human embryonic stem cells. ASCs (10(8)) were then intramuscularly injected into the ischemic leg of patients, with no complication, as judged by an independent committee. Trans-cutaneous oxygen pressure tended to increase in most patients. Ulcer evolution and wound healing showed improvement. CONCLUSIONS: These data demonstrate the feasibility and safety of autologous ASC transplantation in patients with objectively proven CLI not suitable for revascularization. The improved wound healing also supports a putative functional efficiency.

Aging-related decrease of human ASC angiogenic potential is reversed by hypoxia preconditioning through ROS production.

Adipose stroma/stem cells (ASC) represent an ideal source of autologous cells for cell-based therapy. Their transplantation enhances neovascularization after experimental ischemic injury. Aging is associated with a progressive decrease in the regenerative potential of mesenchymal stem cells (MSCs) from bone marrow. This work aims to determine the aging effect on human ASC capacities. First, we show that aging impairs angiogenic capacities of human ASC (hASC) in a mouse ischemic hindlimb model. Although no change in hASC number, phenotype, and proliferation was observed with aging, several mechanisms involved in the adverse effects of aging have been identified in vitro combining a concomitant decrease in (i) ASC ability to differentiate towards endothelial cells, (ii) secretion of proangiogenic and pro-survival factors, and (iii) oxidative stress. These effects were counteracted by a hypoxic preconditioning that improved in vivo angiogenic capacities of hASC from older donors, while hASC from young donors that have a strong ability to manage hypoxic stress were not. Finally, we identified reactive oxygen species (ROS) generation as a key signal of hypoxia on hASC angiogenic capacities. This study demonstrates for the first time that age of donor impaired angiogenic capacities of hASC in ischemic muscle and change in ROS generation by hypoxic preconditioning reverse the adverse effect of aging.

Acceptability of Allogeneic Mesenchymal Stromal Cell-Based Tissue Engineering for the Treatment of Periodontitis: A Qualitative Study in France.

INTRODUCTION AND AIMS: Periodontitis, the main cause of tooth loss in adults, is a public health concern; its incidence increases with age, and its prevalence increases with increasing life expectancy of the population. Innovative therapies such as cell therapy represent promising future solutions for guided tissue regeneration. However, these therapies may be associated with fears and mistrust from the general public. The aim of this study was to estimate the acceptability of an advanced therapy medicinal product combining allogeneic mesenchymal stromal cells from adipose tissue with a natural fibrin hydrogel in the treatment of periodontitis. METHODS: The methodology was based on a qualitative study conducted through semi-structured interviews with patients followed for periodontitis in the Oral Medicine Department of the Toulouse University Hospital, Toulouse, France. Qualitative studies are essential methodologies to understand the patterns of health behaviours, describe illness experiences, and design health interventions in a humanistic and person-centred way of discovering. RESULTS: Eleven interviews (with 4 men and 7 women) were required to reach thematic saturation. Analysis allowed 4 main themes to emerge: (1) perception of new treatments, science, and caregivers; (2) conditions that the treatment must meet; (3) patient perception of the disease; and (4) factors related to the content of the treatment. CONCLUSIONS: Patients find cell therapy for periodontitis to be acceptable. If they express a need to be informed about the benefit/risk ratio, they are not particularly worried about side effects of the treatment, for either allogeneic or blood-derived products. Periodontitis is a prototypical model of chronic inflammatory pathology and is multitissular, with hard- and soft-tissue lesions. In a patient-centred approach, the success of cell therapy will require a bilateral, informed decision, taking into account potential therapeutic effectiveness and patient expectations for regeneration.

A computational model reveals an early transient decrease in fiber cross-linking that unlocks adult regeneration.

The decline in regeneration efficiency after birth in mammals is a significant roadblock for regenerative medicine in tissue repair. We previously developed a computational agent based-model (ABM) that recapitulates mechanical interactions between cells and the extracellular-matrix (ECM), to investigate key drivers of tissue repair in adults. Time calibration alongside a parameter sensitivity analysis of the model suggested that an early and transient decrease in ECM cross-linking guides tissue repair toward regeneration. Consistent with the computational model, transient inhibition or stimulation of fiber cross-linking for the first six days after subcutaneous adipose tissue (AT) resection in adult mice led to regenerative or scar healing, respectively. Therefore, this work positions the computational model as a predictive tool for tissue regeneration that with further development will behave as a digital twin of our in vivo model. In addition, it opens new therapeutic approaches targeting ECM cross-linking to induce tissue regeneration in adult mammals.

The oral organ: A new vision of the mouth as a whole for a gerophysiological approach to healthy aging.

This article brings a new perspective on oral physiology by presenting the oral organ as an integrated entity within the entire organism and its surrounding environment. Rather than considering the mouth solely as a collection of discrete functions, this novel approach emphasizes its role as a dynamic interphase, supporting interactions between the body and external factors. As a resilient ecosystem, the equilibrium of mouth ecological niches is the result of a large number of interconnected factors including the heterogeneity of different oral structures, diversity of resources, external and internal pressures and biological actors. The manuscript seeks to deepen the understanding of age-related changes within the oral cavity and throughout the organism, aligning with the evolving field of gerophysiology. The strategic position and fundamental function of the mouth make it an invaluable target for early prevention, diagnosis, treatment, and even reversal of aging effects throughout the entire organism. Recognizing the oral cavity capacity for sensory perception, element capture and information processing underscores its vital role in continuous health monitoring. Overall, this integrated understanding of the oral physiology aims at advancing comprehensive approaches to the oral healthcare and promoting broader awareness of its implications on the overall well-being.

Periostin Plasma Levels and Changes on Physical and Cognitive Capacities in Community-Dwelling Older Adults.

Periostin, involved in extracellular matrix development and support, has been shown to be elevated in senescent tissues and fibrotic states, transversal signatures of aging. We aimed to explore associations between plasma periostin and physical and cognitive capacity evolution among older adults. Our hypothesis was that higher levels of plasma periostin will be associated with worse physical and mental capacities along time. Analyses included 1 096 participants (mean age = 75.3 years ± 4.4; 63.9% women) from the Multidomain Alzheimer Preventive Trial. Periostin levels (pg/mL) were measured in plasma collected at year 1. Periostin was used in continuous variable, and as a dichotomous variable highest quartile (POSTN+) versus lowest 3 quartiles (POSTN-) were used. Outcomes were measured annually over 4 years and included: gait speed (GS), short physical performance battery (SPPB) score, 5-times sit-to-stand test (5-STS), and handgrip strength (HS) as physical and cognitive composite z-score (CCS) and the Mini-Mental State Examination (MMSE) as cognitive endpoints. Plasma periostin as a continuous variable was associated with the worsening of physical and cognitive capacities over 4 years of follow-up, specifically the SPPB score, the 5-STS, and CCS in full-adjusted models. POSTN+ was associated with worse evolution in the physical (GS: [ß = -0.057, 95% confidence interval (CI) = -0.101, -0.013], SPPB score [ß = -0.736, 95% CI = -1.091, -0.381], 5-STS [ß = 1.681, 95% CI = 0.801, 2.561]) as well as cognitive (CCS [ß = -0.215, 95% CI = -0.335, -0.094]) domains compared to POSTN- group. No association was found with HS or the MMSE score. Our study showed for the first time that increased plasma periostin levels were associated with declines in both physical and cognitive capacities in older adults over a 4-year follow-up. Further research is needed to evaluate whether periostin might be used as a predictive biomarker of functional decline at an older age.

Immune response to human embryonic stem cell-derived cardiac progenitors and adipose-derived stromal cells.

Transplantation of allogeneic human embryonic stem cell-derived cardiac progenitors triggers an immune response. We assessed whether this response could be modulated by the concomitant use of adipose-derived stromal cells (ADSC). Peripheral blood mononuclear cells were collected from 40 patients with coronary artery disease (CAD) and nine healthy controls. Cardiac progenitors (CD15(+) Mesp1(+)) were generated as already reported from the I6 cell line treated with bone morphogenetic protein (BMP)-2. Adipose-derived stromal cells were obtained from abdominal dermolipectomies. We assessed the proliferative response of peripheral lymphocytes from patients and controls to cardiac progenitors cultured on a monolayer of ADSC, to allogeneic lymphocytes in mixed lymphocyte culture and to the T cell mitogen phytohemaglutin A in presence or absence of ADSC. Cardiac progenitors cultured on a monolayer of ADSC triggered a proliferation of lymphocytes from both patients and controls albeit lower than that induced by allogeneic lymphocytes. When cultured alone, ADSC did not induce any proliferation of allogeneic lymphocytes. When added to cultures of lymphocytes, ADSC significantly inhibited the alloantigen or mitogen-induced proliferative response. Compared to healthy controls, lymphocytes from patients presenting CAD expressed a decreased proliferative capacity, in particular to mitogen-induced stimulation. Adipose-derived stromal cells express an immunomodulatory effect that limits both alloantigen and mitogen-induced lymphocyte responses. Furthermore, lymphocytes from patients with CAD are low responders to conventional stimuli, possibly because of their age and disease-associated treatment regimens. We propose that, in combination, these factors may limit the in vivo immunogenicity of cardiac progenitors co-implanted with ADSC in patients with CAD.

A Spectral Principal Component Analysis-Based Framework for Composite Hard/Soft Tissue Fluorescence Image Investigation.

Traditional thin sectioning microscopy of large bone and dental tissue samples using demineralization may disrupt structure morphologies and even damage soft tissues, thus compromising the histopathological investigation. Here, we developed a synergistic and original framework on thick sections based on wide-field multi-fluorescence imaging and spectral Principal Component Analysis (sPCA) as an alternative, fast, versatile, and reliable solution, suitable for highly mineralized tissue structure sustain and visualization. Periodontal 2-mm thick sections were stained with a solution containing five fluorescent dyes chosen for their ability to discriminate close tissues, and acquisitions were performed with a multi-zoom macroscope for blue, green, red, and NIR (near-infrared) emissions. Eigen-images derived from both standard scaler (Std) and Contrast Limited Adaptive Histogram Equalization (Clahe) pre-preprocessing significantly enhanced tissue contrasts, highly suitable for histopathological investigation with an in-depth detail for sub-tissue structure discrimination. Using this method, it is possible to preserve and delineate accurately the different anatomical/morphological features of the periodontium, a complex tooth-supporting multi-tissue. Indeed, we achieve characterization of gingiva, alveolar bone, cementum, and periodontal ligament tissues. The ease and adaptability of this approach make it an effective method for providing high-contrast features that are not usually available in standard staining histology. Beyond periodontal investigations, this first proof of concept of an sPCA solution for optical microscopy of complex structures, especially including mineralized tissues opens new perspectives to deal with other chronic diseases involving complex tissue and organ defects. Overall, such an imaging framework appears to be a novel and convenient strategy for optical microscopy investigation.

[Mesenchymal stem cells: A therapeutic update]. / Les cellules souches mésenchymateuses: Actualités thérapeutiques.

Mesenchymal stem cells/multipotent marrow stromal cells (MSC) have the ability to participate in there construction of tissues both directly by providing repair cells (essentially those originating from mesoderm)and indirectly by modulating inflammatory and immune responses. This wide range of properties makes these cells very appealing to treat various pathological conditions. They have been first used in 1995 as supportive cells to facilitate hematopoietic stem cells engraftment, and then to minimize the deleterious consequences of graft versus host disease by their immunosuppressive function. Their robust osteogenic differentiation capacity has also been evaluated in numerous preclinical settings of healing/repair but more rarely in human clinical trials. During the past 10-15 years, the potential benefit of their paracrine actions has been tested in various situations such as to facilitate repair after cutaneous defects after burns or lower consequences of ischemic strokes. The purpose of this series of short texts is not to give an exhaustive panorama, but to discuss some well-identified indications in four different fields : auto-immune diseases,bone repair, vascular regeneration and eye lesions such as corneal and retinal defects.

MSCs and Inflammatory Cells Crosstalk in Regenerative Medicine: Concerted Actions for Optimized Resolution Driven by Energy Metabolism.

Mesenchymal stromal cells (MSCs) are currently widely used in cell based therapy regarding to their remarkable efficacy in controlling the inflammatory status in patients. Despite recent progress and encouraging results, inconstant therapeutic benefits are reported suggesting that significant breakthroughs in the understanding of MSCs immunomodulatory mechanisms of action remains to be investigated and certainly apprehended from original point of view. This review will focus on the recent findings regarding MSCs close relationship with the innate immune compartment, i.e. granulocytes and myeloid cells. The review will also consider the intercellular mechanism of communication involved, such as factor secretion, cell-cell contact, extracellular vesicles, mitochondria transfer and efferocytosis. Immune-like-properties of MSCs supporting part of their therapeutic effect in the clinical setting will be discussed, as well as their potentials (immunomodulatory, anti-bacterial, anti-inflammatory, anti-oxidant defenses and metabolic adaptation…) and effects mediated, such as cell polarization, differentiation, death and survival on various immune and tissue cell targets determinant in triggering tissue regeneration. Their metabolic properties in term of sensing, reacting and producing metabolites influencing tissue inflammation will be highlighted. The review will finally open to discussion how ongoing scientific advances on MSCs could be efficiently translated to clinic in chronic and age-related inflammatory diseases and the current limits and gaps that remain to be overcome to achieving tissue regeneration and rejuvenation.

Preconditioning by mitochondrial reactive oxygen species improves the proangiogenic potential of adipose-derived cells-based therapy.

OBJECTIVE: Transplantation of adipose-derived stroma cells (ADSCs) stimulates neovascularization after experimental ischemic injury. ADSC proangiogenic potential is likely mediated by their ability to differentiate into endothelial cells and produce a wide array of angiogenic and antiapoptotic factors. Mitochondrial reactive oxygen species (ROS) have been shown to control ADSC differentiation. We therefore hypothesized that mitochondrial ROS production may change the ADSC proangiogenic properties. METHODS AND RESULTS: The use of pharmacological strategies (mitochondrial inhibitors, antimycin, and rotenone, with or without antioxidants) allowed us to specifically and precisely modulate mitochondrial ROS generation in ADSCs. We showed that transient stimulation of mitochondrial ROS generation in ADSCs before their injection in ischemic hindlimb strongly improved revascularization and the number of ADSC-derived CD31-positive cells in ischemic area. Mitochondrial ROS generation increased the secretion of the proangiogenic and antiapoptotic factors, VEGF and HGF, but did not affect ADSC ability to differentiate into endothelial cells, in vitro. Moreover, mitochondrial ROS-induced ADSC preconditioning greatly protect ADSCs against oxidative stress-induced cell death. CONCLUSIONS: Our study demonstrates that in vitro preconditioning by moderate mitochondrial ROS generation strongly increases in vivo ADSC proangiogenic properties and emphasizes the crucial role of mitochondrial ROS in ADSC fate.

Broad-Spectrum Antibacterial Effects of Human Adipose-Derived Stromal Cells.

INTRODUCTION: Many pathological conditions may benefit from cell therapy using mesenchymal stromal cells, particularly from adipose tissue (ASCs). Cells may be grafted in an environment with a remnant polymicrobial component. The aim is to investigate the behavior of ASCs when brought in contact with a large panel of bacteria. MATERIALS AND METHODS: Carboxyfluorescein-labelled bacterial interaction with ASCs was followed by confocal time-lapse microscopy. Costaining with LAMP-1 was also analyzed. Viability of 4 gram-negative and 4 gram-positive bacterial strains after 6 h of coculture with ASCs was assessed by agar colony counting and by flow cytometry using SYTO-62®/propidium iodide (PI) for membrane permeabilization and DiOC6 for depolarization. A murine model of periodontitis was used to assess in vivo antibacterial capacities of ASCs. RESULTS: A significant increase of PI-positive events for all bacterial strains and an increase of the DiOC6 signal were obtained after contact with ASCs. The number of CFU was also significantly decreased for several bacterial strains. 0.4 µm transwell systems illustrated the necessary direct contact to induce maximal bacterial membrane damages. Some bacteria were observed into phagolysosomes, confirming macrophage-like properties of ASCs. In vivo, the bacterial load was significantly lower in the ASC-grafted side compared to the control. CONCLUSION: Our results highlight for the first time a broad range of antibacterial actions of ASCs, by phagocytosis, secretion of oxygenated free radicals and antibacterial molecules. These data are in line with the development of new therapeutic strategies based on ASC transplantation, appropriated in immune-dysbiotic tissue context such as periodontitis or chronic wounds.

Short exposure to cold atmospheric plasma induces senescence in human skin fibroblasts and adipose mesenchymal stromal cells.

Cold Atmospheric Plasma (CAP) is a novel promising tool developed in several biomedical applications such as cutaneous wound healing or skin cancer. Nevertheless, in vitro studies are lacking regarding to CAP effects on cellular actors involved in healthy skin healing and regarding to the mechanism of action. In this study, we investigated the effect of a 3 minutes exposure to CAP-Helium on human dermal fibroblasts and Adipose-derived Stromal Cells (ASC) obtained from the same tissue sample. We observed that CAP treatment did not induce cell death but lead to proliferation arrest with an increase in p53/p21 and DNA damages. Interestingly we showed that CAP treated dermal fibroblasts and ASC developed a senescence phenotype with p16 expression, characteristic morphological changes, Senescence-Associated ß-galactosidase expression and the secretion of pro-inflammatory cytokines defined as the Senescence-Associated Secretory Phenotype (SASP). Moreover this senescence phenotype is associated with a glycolytic switch and an increase in mitochondria content. Despite this senescence phenotype, cells kept in vitro functional properties like differentiation potential and immunomodulatory effects. To conclude, we demonstrated that two main skin cellular actors are resistant to cell death but develop a senescence phenotype while maintaining some functional characteristics after 3 minutes of CAP-Helium treatment in vitro.

Virus-based gene transfer approaches and adipose tissue biology.

The status of adipose tissue changes rapidly. From a simple filler tissue, it successively acquires the status of metabolic active tissue, endocrine tissue, plastic tissue, and finally that of a large reservoir of cells suitable for cell therapy and regenerative medicine. All throughout this story, our knowledge has been largely dependent on genetic tools and gene transfer. Now, the time has come where gene transfer in adipose derived cells can be envisioned, not only for understanding the role or importance of one gene, but also to engineer adipose derived cells for the purpose of therapy by delivering secreted products. In this paper, after a brief overview of adipose tissues, a large part will be devoted to the use of virus-based gene transfer in transducing adipose tissue and cells which reside therein. We also critically review the use of adipose "specific" promoters and the applications already described in the literature.

Transplantation of adipose derived stromal cells is associated with functional improvement in a rat model of chronic myocardial infarction.

AIMS: To determine the effect of transplantation of undifferentiated and cardiac pre-differentiated adipose stem cells compared with bone marrow mononuclear cells (BM-MNC) in a chronic model of myocardial infarction. METHODS: Ninety-five Sprague-Dawley rats underwent left coronary artery ligation and after 1 month received by direct intramyocardial injection either adipose derived stem cells (ADSC), cardiomyogenic cells (AD-CMG) or BM-MNC from enhanced-Green Fluorescent Protein (eGFP) mice. The control group was treated with culture medium. Heart function was assessed by echocardiography and 18F-FDG microPET. Cell engraftment, differentiation, angiogenesis and fibrosis in the scar tissue were also evaluated by (immuno)histochemistry and immunofluorescence. RESULTS: One month after cell transplantation, ADSC induced a significant improvement in heart function (LVEF 46.3+/-9.6% versus 27.7+/-8% pre-transplant) and tissue viability (64.78+/-7.2% versus 55.89+/-6.3% pre-transplant). An increase in the degree of angiogenesis and a decrease in fibrosis were also detected. Although transplantation of AD-CMG or BM-MNC also had a positive, albeit smaller, effect on angiogenesis and fibrosis in the infarcted hearts, this benefit did not translate into a significant improvement in heart function or tissue viability. CONCLUSION: These results indicate that transplantation of adipose derived cells in chronic infarct provides a superior benefit to cardiac pre-differentiated ADSC and BM-MNC.

Periodontal Tissue Regeneration Using Syngeneic Adipose-Derived Stromal Cells in a Mouse Model.

Current treatment of periodontitis is still associated with a high degree of variability in clinical outcomes. Recent advances in regenerative medicine by mesenchymal cells, including adipose stromal cells (ASC) have paved the way to improved periodontal regeneration (PD) but little is known about the biological processes involved. Here, we aimed to use syngeneic ASCs for periodontal regeneration in a new, relevant, bacteria-induced periodontitis model in mice. Periodontal defects were induced in female C57BL6/J mice by oral gavage with periodontal pathogens. We grafted 2 × 105 syngeneic mouse ASCs expressing green fluorescent protein (GFP) (GFP+/ASC) within a collagen vehicle in the lingual part of the first lower molar periodontium (experimental) while carrier alone was implanted in the contralateral side (control). Animals were sacrificed 0, 1, 6, and 12 weeks after treatment by GFP+/ASC or vehicle graft, and microscopic examination, immunofluorescence, and innovative bio-informatics histomorphometry methods were used to reveal deep periodontium changes. From 1 to 6 weeks after surgery, GFP+ cells were identified in the periodontal ligament (PDL), in experimental sites only. After 12 weeks, cementum regeneration, the organization of PDL fibers, the number of PD vessels, and bone morphogenetic protein-2 and osteopontin expression were greater in experimental sites than in controls. Specific stromal cell subsets were recruited in the newly formed tissue in ASC-implanted periodontium only. These data suggest that ASC grafting in diseased deep periodontium, relevant to human pathology, induces a significant improvement of the PDL microenvironment, leading to a recovery of tooth-supporting tissue homeostasis. Stem Cells Translational Medicine 2017;6:656-665.