Human adipose-derived cells: an update on the transition to clinical translation

Preparation and in vitro evaluation of cell adhesion and long-term proliferation of stem cells cultured on silibinin co-embedded PLGA/Collagen electrospun composite nanofibers

The present research aims to evaluate the efficacy of Silibinin-loaded mesoporous silica nanoparticles (Sil@MSNs) immobilized into polylactic-co-glycolic acid/Collagen (PLGA/Col) nanofibers on the in vitro proliferation of adipose-derived stem cells (ASCs) and cellular senescence. Here, the fabricated electrospun PLGA/Col composite scaffolds were coated with Sil@MSNs and their physicochemical properties were examined by FTIR, FE-SEM, and TGA. The growth, viability and proliferation of ASCs were investigated using various biological assays including PicoGreen, MTT, and RT-PCR after 21 days. The proliferation and adhesion of ASCs were supported by the biological and mechanical characteristics of the Sil@MSNs PLGA/Col composite scaffolds, according to FE- SEM. PicoGreen and cytotoxicity analysis showed an increase in the rate of proliferation and metabolic activity of hADSCs after 14 and 21 days, confirming the initial and controlled release of Sil from nanofibers. Gene expression analysis further confirmed the increased expression of stemness markers as well as hTERT and telomerase in ASCs seeded on Sil@MSNs PLGA/Col nanofibers compared to the control group. Ultimately, the findings of the present study introduced Sil@MSNs PLGA/Col composite scaffolds as an efficient platform for long-term proliferation of ASCs in tissue engineering.

Long-Term Safety of Bone Regeneration Using Autologous Stromal Vascular Fraction and Calcium Phosphate Ceramics: A 10-Year Prospective Cohort Study

This prospective cohort study aimed to assess long-term safety, dental implant survival, and clinical and radiological outcomes after maxillary sinus floor elevation (MSFE; lateral window technique) using freshly isolated autologous stromal vascular fraction (SVF) combined with calcium phosphate ceramics. All 10 patients previously participating in a phase I trial were included in a 10-year follow-up. They received either β-tricalcium phosphate (β-TCP; n = 5) or biphasic calcium phosphate (BCP; n = 5) with SVF-supplementation on one side (study). Bilaterally treated patients (6 of 10; 3 β-TCP, 3 BCP) received only calcium phosphate on the opposite side (control). Clinical and radiological assessments were performed on 44 dental implants at 1-month pre-MSFE, and 0.5- to 10-year post-MSFE. Implants were placed 6 months post-MSFE. No adverse events or pathology was reported during a 10-year follow-up. Forty-three dental implants (98%) remained functional. Control and study sides showed similar peri-implant soft-tissue quality, sulcus bleeding index, probing depth, plaque index, keratinized mucosa width, as well as marginal bone loss (0-6 mm), graft height loss (0-6 mm), and graft volume reduction. Peri-implantitis was observed around 6 implants (control: 4; study: 2) in 3 patients. This study is the first to demonstrate the 10-year safety of SVF-supplementation in MSFE for jawbone reconstruction. SVF-supplementation showed enhanced bone regeneration in the short term (previous study) and led to no abnormalities clinically and radiologically in the long term.

Cell-free fat extract restores hair loss: a novel therapeutic strategy for androgenetic alopecia

BACKGROUND

Androgenetic alopecia (AGA) is one of the most common hair loss diseases worldwide. However, current treatments including medicine, surgery, and stem cells are limited for various reasons. Cell-free fat extract (CEFFE), contains various cell factors, may have potential abilities in treating AGA. This study aims to evaluate the safety, effectiveness and the underlying mechanism of CEFFE in treating AGA.

METHODS

Sex hormone evaluation, immunogenicity assay and genotoxicity assay were conducted for CEFFE. In vivo study, male C57BL/6 mice were injected subcutaneously with dihydrotestosterone (DHT) and were treated with different concentration of CEFFE for 18 days (five groups and n = 12 in each group: Control, Model, CEFFELow, CEFFEMiddle, CEFFEHigh). Anagen entry rate and hair coverage percentage were analyzed through continuously taken gross photographs. The angiogenesis and proliferation of hair follicle cells were evaluated by hematoxylin-eosin, anti-CD31, and anti-Ki67 staining. In vitro study, dermal papilla cells (DPCs) were incubated with different concentrations of CEFFE, DHT, or CEFFE + DHT, followed by CCK-8 assay and flow cytometry to evaluate cell proliferation cycle and apoptosis. The intracellular DHT level were assessed by enzyme-linked immunosorbent assay. The expression of 5α-reductase type II, 3α-hydroxysteroid dehydrogenase and androgen receptor were assessed through reverse transcription-quantitative polymerase chain reaction (RT-qPCR) or/and western blot.

RESULTS

In CEFFE-treated mice, an increase in the anagen entry rate and hair coverage percentage was observed. The number of CD31-positive capillaries and Ki67-positive cells were increased, suggesting that CEFFE promoted the proliferation of DPCs, modulated the cell cycle arrest, inhibited apoptosis caused by DHT, reduced the intracellular concentration of DHT in DPCs, and downregulated the expression of AR.

CONCLUSIONS

CEFFE is a novel and effective treatment option for AGA through producing an increased hair follicle density and hair growth rate. The proposed mechanisms are through the DHT/AR pathway regulation and regional angiogenesis ability.

Tendon Transection Healing Can Be Improved With Adipose-Derived Stem Cells Cultured With Growth Differentiation Factor 5 and Platelet-Derived Growth Factor

BACKGROUND

As hand surgeons, tendon injuries and lacerations are a particularly difficult problem to treat, as poor healing potential and adhesions hamper optimal recovery. Adipose-derived stem cells (ADSCs) have been shown to aid in rat Achilles tendon healing after a puncture defect, and this model can be used to study tendon healing in the upper extremity. We hypothesized that ADSCs cultured with growth differentiation factor 5 (GDF5) and platelet-derived growth factor (PDGF) would improve tendon healing after a transection injury.

METHODS

Rat Achilles tendons were transected and then left either unrepaired or repaired. Both groups were treated with a hydrogel alone, a hydrogel with ADSCs, or a hydrogel with ADSCs that were cultured with GDF5 and PDGF prior to implantation. Tissue harvested from the tendons was evaluated for gene expression of several genes known to play an important role in successful tendon healing. Histological examination of the tendon healing was also performed.

RESULTS

In both repaired and unrepaired tendons, those treated with ADSCs cultured with GDF5/PDGF prior to implantation showed the best tendon fiber organization, the smallest gaps, and the most organized blood vessels. Treatment with GDF5/PDGF increased expression of the protenogenesis gene SOX9, promoted cell-to-cell connections, improved cellular proliferation, and enhanced tissue remodeling.

CONCLUSIONS

Adipose-derived stem cells cultured with GDF5/PDGF prior to implantation can promote tendon repair by improving cellular proliferation, tenogenesis, and vascular infiltration. This effect results in a greater degree of organized tendon healing.

Highly Pluripotent Adipose-Derived Stem Cell-Enriched Nanofat: A Novel Translational System in Stem Cell Therapy

Fat graft is widely used in plastic and reconstructive surgery. The size of the injectable product, the unpredictable fat resorption rates, and subsequent adverse effects make it tricky to inject untreated fat into the dermal layer. Mechanical emulsification of fat tissue, which Tonnard introduced, solves these problems, and the product obtained was called nanofat. Nanofat is widely used in clinical and aesthetic settings to treat facial compartments, hypertrophic and atrophic scars, wrinkle attenuation, skin rejuvenation, and alopecia. Several studies demonstrate that the tissue regeneration effects of nanofat are attributable to its rich content of adipose-derived stem cells. This study aimed to characterize Hy-Tissue Nanofat product by investigating morphology, cellular yield, adipose-derived stem cell (ASC) proliferation rate and clonogenic capability, immunophenotyping, and differential potential. The percentage of SEEA3 and CD105 expression was also analyzed to establish the presence of multilineage-differentiating stress-enduring (MUSE) cell. Our results showed that the Hy-Tissue Nanofat kit could isolate 3.74 × 10⁴ ± 1.31 × 10⁴ proliferative nucleated cells for milliliter of the treated fat. Nanofat-derived ASC can grow in colonies and show high differentiation capacity into adipocytes, osteocytes, and chondrocytes. Moreover, immunophenotyping analysis revealed the expression of MUSE cell antigen, making this nanofat enriched of pluripotent stem cell, increasing its potential in regenerative medicine. The unique characteristics of MUSE cells give a simple, feasible strategy for treating a variety of diseases.

The role of mesenchymal stem cell transplantation for ischemic stroke and recent research developments

Ischemic stroke is a common cerebrovascular disease that seriously affects human health. However, most patients do not practice self-care and cannot rely on the current clinical treatment for guaranteed functional recovery. Stem cell transplantation is an emerging treatment studied in various central nervous system diseases. More importantly, animal studies show that transplantation of mesenchymal stem cells (MSCs) can alleviate neurological deficits and bring hope to patients suffering from ischemic stroke. This paper reviews the biological characteristics of MSCs and discusses the mechanism and progression of MSC transplantation to provide new therapeutic directions for ischemic stroke.

Cross talk of vasopressin conditioned cell therapy in ischemic heart disease: Role of oxidative stress markers

Objectives

Background: Impaired coronary blood flow causes cardiac ischemia. Cellular therapy is a new approach to the treatment of myocardial ischemia. This study aimed to investigate the effect of adipose tissue-derived mesenchymal stem cells (AD-MSCs) conditioned with vasopressin on oxidative stress, perivascular collagen, and angiogenesis caused by myocardial infarction (MI) in rats.

Materials and Methods

We divided 40 male albino Wistar rats into 4 groups; Control group; No intervention; in experimental groups, after it generated induced MI on models, it divided into three groups: Vehicle group (150 μl of cell-free culture medium received); ASC-MI group (6× 10⁶ AD-MSC received) and AVP-ASC-MI group (received 6 × 10⁶ AD-MSC conditioned with 10 nM vasopressin). Then, histologic parameters and anti-oxidant enzymes were evaluated 7 days post-MI cell injection.

Results

Arterial muscle diameter improved and collagen deposition around the coronary arteries decreased in cell-received groups compared with the vehicle group. Malondialdehyde (MDA), catalase (CAT), (GSH) Glutathione, and Total Anti-oxidant Capacity (TAC) parameters were not significantly different between the cells received groups compared with the vehicle group. But the Catalase (CAT) parameter in the ASC-MI group had a significant increase from the control group.

Conclusion

We prepared direct evidence that intramyocardial injection of AD-MSCs reveals the positive cardiac remodeling post-MI in rats, and these useful effects can be more enhanced by administrating injection of conditioned ADSCs with vasopressin.

Adipose-derived stromal vascular fraction (SVF) in scar treatment: a systematic review protocol

BACKGROUND

Autologous adipose-derived stromal vascular fraction (SVF) is an emerging therapy that is being pioneered as a potential treatment for keloids and hypertrophic scars. Up to this point, there isn't a cure for keloids and hypertrophic scars yet they comprise the commonest benign skin disorders. Despite published studies reporting potential therapeutic benefits of SVF, their use and efficacy on scar improvement are not clearly described. The aim of this review is to describe the clinical practice involved in harvesting, processing, utilization of SVF, and associated efficacy in scar treatment.

METHODS

We shall include published clinical articles evaluating the efficacy of SVF on improving scar characteristics and assessment scores among adults with keloids or hypertrophic scars. Article search of Medline/PubMed, Cochrane Library and Embase using Mesh terms of "scars" and "stromal vascular fraction" combined with the Boolean operators ("AND", "OR") will be performed by two independent researchers following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) statement. The primary outcome measure will be the mean difference in the Scar characteristics including Scar assessment scores, scar thickness among others.

DATA SYNTHESIS

Descriptive data synthesis and mean differences between treatment arms will be calculated for the primary outcome of the scar assessment scores. In case more than three studies provide consistent characteristics of the scar assessment scores, a meta-analysis will be conducted.

DISCUSSION

Evidence obtained from the systematic review will form the foundation upon which further clinical trials research will be conducted in evaluating the efficacy of autologous adipose-derived stromal vascular fraction in keloid and hypertrophic scar. The systematic review has been submitted to the PROSPERO database and is currently under review.

Mesenchymal stem cells are prospective novel off-the-shelf wound management tools

Chronic/non-healing cutaneous wounds pose a debilitating burden on patients and healthcare system. Presently, treatment modalities are rapidly shifting pace from conventional methods to advanced wound care involving cell-based therapies. Mesenchymal stem cells (MSCs) have come across as a prospective option due to its pleiotropic functions viz. non-immunogenicity, multipotency, multi-lineage plasticity and secretion of growth factors, cytokines, microRNAs (miRNA), exosomes, and microvesicles as part of their secretome for assisting wound healing. We outline the therapeutic role played by MSCs and its secretome in suppressing tissue inflammation, causing immunomodulation, aiding angiogenesis and assisting in scar-free wound healing. We further assess the mechanism of action by which MSCs contribute in manifesting tissue repair. The review flows ahead in exploring factors that influence healing behavior including effect of multiple donor sites, donor age and health status, tissue microenvironment, and in vitro expansion capability. Moving ahead, we overview the advancements achieved in extending the lifespan of cells upon implantation, influence of genetic modifications aimed at altering MSC cargo, and evaluating bioengineered matrix-assisted delivery methods toward faster healing in preclinical and clinical models. We also contribute toward highlighting the challenges faced in commercializing cell-based therapies as standard of care treatment regimens. Finally, we strongly advocate and highlight its application as a futuristic technology for revolutionizing tissue regeneration.

Efficacy and Safety of Treatment of Complex Idiopathic Fistula-in-Ano Using Autologous Centrifuged Adipose Tissue Containing Progenitor Cells: A Randomized Controlled Trial

BACKGROUND

Mesenchymal stem cells derived from adipose tissue have been successfully used to promote sphincter-saving anal fistula healing.

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of the use of autologous centrifuged adipose tissue in the healing process of cryptoglandular complex anal fistulas.

DESIGN

This is a randomized controlled trial.

SETTINGS

This study was conducted at a single center.

PATIENTS

Patients with complex perianal fistulas not associated with Crohn's disease were included. Rectovaginal fistulas were not included.

INTERVENTIONS

Patients were randomly allocated to receive treatment with centrifuged adipose tissue injection (experimental group) and without injection (control group) in combination with fistula surgery.

MAIN OUTCOME MEASURES

The primary outcome was defined as the proportion of patients with complete fistula closure at 4 weeks (short-term outcome) and 6 months after surgery (long-term outcome). Healing was defined as when the external opening was closed with no perianal discharge on clinical assessment. The secondary outcome was safety that was evaluated by the analysis of adverse events up to 3 months after surgery. Pelvic MRI was performed at 3 months to assure safety and the accuracy of the clinical determination of healing. Postoperative pain, return to work/daily activities, persistent closure at 6 months, fecal incontinence, and patient satisfaction were evaluated.

RESULTS

Fifty-eight patients who received centrifuged adipose tissue injection and 58 patients who did not receive centrifuged adipose tissue injection were included in the safety and efficacy analysis. After 4 weeks, the healing rate was 63.8% in the experimental group compared with 15.5% in the control group (p < 0.001). No major adverse events were recorded. Postoperative anal pain was significantly lower in the injection group. Time taken to return to work/daily activities was significantly shorter in the experimental group (3 days) than in the control group (17 days). At 6 months, persistent closure was similar in the 2 groups (86.2% vs 81%). Fecal Incontinence Score at 6 months after surgery was identical to the preoperative score. Patient satisfaction was high in both groups.

LIMITATIONS

The absence of blinding, the lack of correlation between stem cell content, and the clinical outcome were limitations of the study.

CONCLUSIONS

Autologous centrifuged adipose tissue injection may represent a safe, efficacious, and inexpensive option for the treatment of complex fistula-in-ano. See Video Abstract at http://links.lww.com/DCR/B607.

CLINICAL TRIALS REGISTRATION

URL: https://www.clinicaltrials.gov. Identifier: NCT04326907.

EFICACIA Y SEGURIDAD DEL TRATAMIENTO DE LA FSTULA ANAL COMPLEJA IDIOPTICA UTILIZANDO TEJIDO ADIPOSO CENTRIFUGADO AUTLOGO QUE CONTIENE CLULAS PROGENITORAS UN ENSAYO CONTROLADO ALEATORIO

ANTECEDENTES:Las células madre mesenquimales derivadas del tejido adiposo se han utilizado con éxito para promover la curación de la fístula anal con preservación de esfínter.OBJETIVO:El objetivo de este estudio fue evaluar la eficacia y seguridad del uso de tejido adiposo autólogo centrifugado en el proceso de cicatrización de fístulas anales complejas de origen criptoglandular.DISEÑO:Ensayo controlado aleatorio.ENTORNO CLÍNICO:Estudio unicéntrico.PACIENTES:Se incluyeron pacientes con fístulas perianales complejas no asociadas a Enfermedad de Crohn. No se incluyeron las fístulas rectovaginales.INTERVENCIONES:Los pacientes fueron asignados aleatoriamente para recibir tratamiento con inyección de tejido adiposo centrifugado (grupo experimental) y sin inyección (grupo de control) en combinación con cirugía de fístula.PRINCIPALES MEDIDAS DE VALORACIÓN:El resultado primario se definió como la proporción de pacientes con cierre completo de la fístula a las 4 semanas (resultado a corto plazo) y 6 meses después de la cirugía (resultado a largo plazo). La curación se definió cuando orificio externo se cerró sin secreción perianal en la valoración clínica. El resultado secundario fue la seguridad que se evaluó mediante el análisis de los eventos adversos (EA) hasta 3 meses después de la cirugía. La resonancia magnética pélvica se realizó a los 3 meses para garantizar la seguridad y la precisión clínica de la curación. Se evaluó el dolor postoperatorio, el regreso al trabajo / actividades diarias, el cierre persistente a los 6 meses, la incontinencia fecal y la satisfacción del paciente.RESULTADOS:Cincuenta y ocho pacientes que recibieron inyección de tejido adiposo centrifugado y 58 pacientes que no recibieron inyección de tejido adiposo centrifugado se incluyeron en el análisis de seguridad y eficacia. Después de 4 semanas, la tasa de curación fue del 63,8% en el grupo experimental en comparación con el 15,5% en el grupo de control (p <0,001). No se registraron eventos adversos importantes. El dolor anal posoperatorio fue significativamente menor en el grupo de inyección. El tiempo necesario para volver al trabajo / actividades diarias fue significativamente menor en el grupo experimental (3 días) con respecto al grupo de control (17 días). A los 6 meses, el cierre persistente fue similar en los dos grupos (86,2% vs 81%). La puntuación de incontinencia fecal a los 6 meses después de la cirugía fue idéntica a la puntuación preoperatoria. La satisfacción del paciente fue muy alta en ambos grupos.LIMITACIONES:Ausencia de cegamiento, falta de correlación entre el contenido de células madre y el resultado clínico.CONCLUSIONES:La inyección de tejido adiposo centrifugado autólogo puede representar una opción segura, eficaz y económica para el tratamiento de la fístula anal compleja.Registro de ensayos clínicos: www.clinicaltrials.gov, identificador NCT04326907; No patrocinado.Consulte Video Resumen en http://links.lww.com/DCR/B607.

Role of Apoptosis in Wound Healing and Apoptosis Alterations in Microgravity

Functioning as the outermost self-renewing protective layer of the human organism, skin protects against a multitude of harmful biological and physical stimuli. Consisting of ectodermal, mesenchymal, and neural crest-derived cell lineages, tissue homeostasis, and signal transduction are finely tuned through the interplay of various pathways. A health problem of astronauts in space is skin deterioration. Until today, wound healing has not been considered as a severe health concern for crew members. This can change with deep space exploration missions and commercial spaceflights together with space tourism. Albeit the molecular process of wound healing is not fully elucidated yet, there have been established significant conceptual gains and new scientific methods. Apoptosis, e.g., programmed cell death, enables orchestrated development and cell removal in wounded or infected tissue. Experimental designs utilizing microgravity allow new insights into the role of apoptosis in wound healing. Furthermore, impaired wound healing in unloading conditions would depict a significant challenge in human-crewed exploration space missions. In this review, we provide an overview of alterations in the behavior of cutaneous cell lineages under microgravity in regard to the impact of apoptosis in wound healing. We discuss the current knowledge about wound healing in space and simulated microgravity with respect to apoptosis and available therapeutic strategies.

Ovarian Cancer Stem Cells: Characterization and Role in Tumorigenesis

Ovarian cancer is a heterogenous disease with variable clinicopathological and molecular mechanisms being responsible for tumorigenesis. Despite substantial technological improvement, lack of early diagnosis contributes to its highest mortality. Ovarian cancer is considered to be the most lethal female gynaecological cancer across the world. Conventional treatment modules with platinum- and Taxane-based chemotherapy can cause an initial satisfactory improvement in ovarian cancer patients. However, approximately 75-80% patients of advanced stage ovarian cancer, experience relapse and nearly 40% have overall poor survival rate. It has been observed that a subpopulation of cells referred as cancer stem cells (CSCs), having self renewal property, escape the conventional chemotherapy because of their quiescent nature. Later, these CSCs following its interaction with microenvironment and release of various inflammatory cytokines, chemokines and matrix metalloproteinases, induce invasion and propagation to distant organs of the body mainly peritoneal cavity. These CSCs can be enriched by their specific surface markers such as CD44, CD117, CD133 and intracellular enzyme such as aldehyde dehydrogenase. This tumorigenicity is further aggravated by the epithelial to mesenchymal transition of CSCs and neovascularisation via epigenetic reprogramming and over-expression of various signalling cascades such as Wnt/β-catenin, NOTCH, Hedgehog, etc. to name a few. Hence, a comprehensive understanding of various cellular events involving interaction between cancer cells and cancer stem cells as well as its surrounding micro environmental components would be of unmet need to achieve the ultimate goal of better management of ovarian cancer patients. This chapter deals with the impact of ovarian cancer stem cells in tumorigenesis which would help in the implementation of basic research into the clinical field in the form of translational research in order to reduce the morbidity and mortality in ovarian cancer patients through amelioration of diagnosis and impoverishment of therapeutic resistance.

Effects of hydroxyapatite-coated nonwoven polyethylene/polypropylene fabric on non-mesodermal lineage-specific differentiation of human adipose-derived stem cells

Objective

Compared to other stem cells, the multipotency of human adipose-derived mesenchymal stem cells (ASCs) is limited. Effective approaches that trigger or enhance lineage-specific transdifferentiation are highly envisaged in the improvement of ASCs-based cell therapies. Using Immunofluorescence assays and the secretion of cardiac troponin T (cTnT) protein, we studied the impact of two substrates: Hydroxyapatite (HAp)-coated nonwoven polyethylene (PET)/polypropylene (PP) fabric and glass surfaces, representing 3 dimensional (D) and 2 D environments respectively, on the induction of cardiomyocytes – a non-mesodermal cell type from ASCs for 1–5 weeks.

Results

ASCs were successfully isolated from human adipose tissue under cGMP conditions. Within 1–3 weeks, expression of cTnT in the induced 3D cultures was overall significantly higher (P < 0.021) than that in the induced 2D cultures or controls (P < 0.0009). Remarkably, after 3 weeks of culture, cTnT secretion in the induced 3D cultures gradually declined, nearly reaching levels observed in the 2D cultures. The results show that HAp-coated nonwoven PE/PP fabric could enhance lineage-specific differentiation of ASCs toward cardiac-like cells. However, the fabric might suppress growth of the transformed cells. These preliminary findings encourage further interest in validating the fabric’s potential in improving ASCs transdifferentiation.

Adipose tissue and the vascularization of biomaterials: Stem cells, microvascular fragments and nanofat-a review

Tissue defects in the human body after trauma and injury require precise reconstruction to regain function. Hence, there is a great demand for clinically translatable approaches with materials that are both biocompatible and biodegradable. They should also be able to adequately integrate within the tissue through sufficient vascularization. Adipose tissue is abundant and easily accessible. It is a valuable tissue source in regenerative medicine and tissue engineering, especially with regard to its angiogenic potential. Derivatives of adipose tissue, such as microfat, nanofat, microvascular fragments, stromal vascular fraction and stem cells, are commonly used in research, but also clinically to enhance the vascularization of implants and grafts at defect sites. In plastic surgery, adipose tissue is harvested via liposuction and can be manipulated in three ways (macro-, micro- and nanofat) in the operating room, depending on its ultimate use. Whereas macro- and microfat are used as a filling material for soft tissue injuries, nanofat is an injectable viscous extract that primarily induces tissue remodeling because it is rich in growth factors and stem cells. In contrast to microfat that adds volume to a defect site, nanofat has the potential to be easily combined with scaffold materials due to its liquid and homogenous consistency and is particularly attractive for blood vessel formation. The same is true for microvascular fragments that are easily isolated from adipose tissue through collagenase digestion. In preclinical animal models, it has been convincingly shown that these vascular fragments inosculate with host vessels and subsequently accelerate scaffold perfusion and host tissue integration. Adipose tissue is also an ideal source of stem cells. It yields larger quantities of cells than any other source and is easier to access for both the patient and doctor compared with other sources such as bone marrow. They are often used for tissue regeneration in combination with biomaterials. Adipose-derived stem cells can be applied unmodified or as single cell suspensions. However, certain pretreatments, such as cultivation under hypoxic conditions or three-dimensional spheroids production, may provide substantial benefit with regard to subsequent vascularization in vivo due to induced growth factor production. In this narrative review, derivatives of adipose tissue and the vascularization of biomaterials are addressed in a comprehensive approach, including several sizes of derivatives, such as whole fat flaps for soft tissue engineering, nanofat or stem cells, their secretome and exosomes. Taken together, it can be concluded that adipose tissue and its fractions down to the molecular level promote, enhance and support vascularization of biomaterials. Therefore, there is a high potential of the individual fat component to be used in regenerative medicine.

Pretreatment of Diabetic Adipose-derived Stem Cells with mitoTEMPO Reverses their Defective Proangiogenic Function in Diabetic Mice with Critical Limb Ischemia

Adipose-derived stem cells (ADSCs) have the ability to migrate to injury sites and facilitate tissue repair by promoting angiogenesis. However, the therapeutic effect of ADSCs from patients with diabetes is impaired due to oxidative stress. Given that diabetes is a group of metabolic disorders and mitochondria are a major source of reactive oxygen species (ROS), it is possible that mitochondrial ROS plays an important role in the induction of diabetic ADSC (dADSC) dysfunction. ADSCs isolated from diabetic mice were treated with mitoTEMPO, a mitochondrial ROS scavenger, or TEMPO, a universal ROS scavenger, for three passages. The results showed that pretreatment with mitoTEMPO increased the proliferation, multidifferentiation potential, and the migration and proangiogenic capacities of dADSCs to levels similar to those of ADSCs from control mice, whereas pretreatment with TEMPO showed only minor effects. Mechanistically, mitoTEMPO pretreatment enhanced the mitochondrial antioxidant capacity of dADSCs, and knockdown of superoxide dismutase reduced the restored mitochondrial antioxidant capacity and attenuated the proangiogenic effects induced by mitoTEMPO pretreatment. In addition, mitoTEMPO pretreatment improved the survival of dADSCs in diabetic mice with critical limb ischemia, showing protective effects similar to those of control ADSCs. Pretreatment of dADSCs with mitoTEMPO decreased limb injury and improved angiogenesis in diabetic mice with critical limb ischemia. These findings suggested that short-term pretreatment of dADSCs with a mitochondrial ROS scavenger restored their normal functions, which may be an effective strategy for improving the therapeutic effects of ADSC-based therapies in patients with diabetes.

Biological Features Implies Potential Use of Autologous Adipose-Derived Stem/Progenitor Cells in Wound Repair and Regenerations for the Patients with Lipodystrophy

A paradigm shift in plastic and reconstructive surgery is brought about the usage of cell-based therapies for wound healing and regeneration. Considering the imitations in the reconstructive surgeries in restoring tissue loss and deficiency, stem cell-based therapy, in particular, has been expected to pave the way for a new solution to the regenerative approaches. Limitations in the reconstructive surgeries in restoring tissue loss and deficiency have paved the way for new regenerative approaches. Among them, adipose-derived stem/progenitor cells (ADSCs)-based therapy could be the most promising clue, since ADSCs have pluripotent differentiation capabilities not only in adipocytes but also in a variety of cell types. Accumulating evidences have indicated that the unfavorable development of adipose-tissue damage, namely, lipodystrophy, is a systemic complication, which is closely related to metabolic abnormality. Considering ADSC-based regenerative medicine should be applied for the treatment of lipodystrophy, it is inevitable to ascertain whether the ADSCs obtained from the patients with lipodystrophy are capable of being used. It will be very promising and realistic if this concept is applied to lipoatrophy; one form of lipodystrophies that deteriorates the patients’ quality of life because of excessive loss of soft tissue in the exposed areas such as face and extremities. Since lipodystrophy is frequently observed in the human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART), the present study aims to examine the biological potentials of ADSCs isolated from the HIV-infected patients with lipodystrophy associated with the HAART treatment. Growth properties, adipogenic differentiation, and mitochondrial reactive oxygen species (ROS) production were examined in ADSCs from HIV-infected and HIV-uninfected patients. Our results clearly demonstrated that ADSCs from both patients showed indistinguishable growth properties and potentials for adipocyte differentiation in vitro. Thus, although the number of cases were limited, ADSCs isolated from the patients with lipodystrophy retain sufficient physiological and biological activity for the reconstitution of adipose-tissue, suggesting that ADSCs from the patients with lipodystrophy could be used for autologous ADSC-based regenerative therapy.

The role of epigenetic modifications in the osteogenic differentiation of adipose-derived stem cells

Over the last decade, stem cells have drawn extensive attention from scientists due to their full potential in tissue engineering, gene therapy, and cell therapy. Adipose-derived stem cells (ADSCs), which represent one type of mesenchymal stem cell (MSC), hold great promise in bone tissue engineering due to their painless collection procedure, their ability to self-renew and their multi-lineage differentiation properties. Major epigenetic mechanisms, which involve DNA methylation, histone modifications and RNA interference (RNAi), are known to represent one of the determining factors of ADSC fate and differentiation. Understanding the epigenetic modifications of ADSCs may provide a clue for improving stem cell therapy in bone repair and regeneration. The aim of this review is to present the recent advances in understanding the epigenetic mechanisms that facilitate ADSC differentiation into an osteogenic lineage, in addition to the characteristics of the main epigenetic modifications.

Evaluation of tenogenic differentiation potential of selected subpopulations of human adipose-derived stem cells

Identification of a suitable cell source and bioactive agents guiding cell differentiation towards tenogenic phenotype represents a prerequisite for advancement of cell-based therapies for tendon repair. Human adipose-derived stem cells (hASCs) are a promising, yet intrinsically heterogenous population with diversified differentiation capacities. In this work, we investigated antigenically-defined subsets of hASCs expressing markers related to tendon phenotype or associated with pluripotency that might be more prone to tenogenic differentiation, when compared to unsorted hASCs. Subpopulations positive for tenomodulin (TNMD+ hASCs) and stage specific early antigen 4 (SSEA-4+ hASCs), as well as unsorted ASCs were cultured up to 21 days in basic medium or media supplemented with TGF-β3 (10 ng/ml), or GDF-5 (50 ng/ml). Cell response was evaluated by analysis of expression of tendon-related markers at gene level and protein level by real time RT-PCR, western blot, and immunocytochemistry. A significant upregulation of scleraxis was observed for both subpopulations and unsorted hASCs in the presence of TGF-β3. More prominent alterations in gene expression profile in response to TGF-β3 were observed for TNMD+ hASCs. Subpopulations evidenced an increased collagen III and TNC deposition in basal medium conditions in comparison with unsorted hASCs. In the particular case of TNMD+ hASCs, GDF-5 seems to influence more the deposition of TNC. Within hASCs populations, discrete subsets could be distinguished offering varied sensitivity to specific biochemical stimulation leading to differential expression of tenogenic components suggesting that cell subsets may have distinctive roles in the complex biological responses leading to tenogenic commitment to be further explored in cell based strategies for tendon tissues.

Improved vascularisation but inefficient in vivo bone regeneration of adipose stem cells and poly-3-hydroxybutyrate-co-3-hydroxyvalerate scaffolds in xeno-free conditions

Bone defects are a common clinical situation. However, bone regeneration remains a challenge and faces the limitation of poor engraftment due to deficient vascularisation. Poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-HV) and human adipose stem cells (hASC) are promising for vascularisation and bone regeneration. Therefore, we sought to investigate the bone regenerative capacity of hASCs cultured in allogeneic human serum (aHS) and PHB-HV scaffolds in a nude mouse model of the critical-sized calvarial defect. We evaluated bone healing for three treatment groups: empty (control), PHB-HV and PHB-HV + hASCs. The pre-implant analysis showed that hASCs colonised the PHB-HV scaffolds maintaining cell viability before implantation. Histological analysis revealed that PHB-HV scaffolds were tolerated in vivo; they integrated with adjacent tissue eliciting a response like a foreign body reaction, and tiny primary bone was observed only in the PHB-HV group. Also, the μ-CT analysis revealed only approximately 10% of new bone in the bone defect area in both the PHB-HV and PHB-HV + hASCs groups. The expression of BGLAP and its protein (osteocalcin) by PHB-HV + hASCs group and native bone was similar while the other bone markers RUNX2, ALPL and COL1A1 were upregulated, but this expression remained significantly lower compared to the native bone. Nevertheless, the PHB-HV group showed neovascularisation at 12 weeks post-implantation while PHB-HV + hASCs group also exhibited higher VEGFA expression as well as a higher number of vessels at 4 weeks post-implantation, and, consequently, earlier neovascularisation. This neovascularisation must be due to scaffold architecture, improved by hASCs, that survived for the long term in vivo in the PHB-HV + hASCs group. These results demonstrated that hASCs cultured in aHS combined with PHB-HV scaffolds were ineffective to promote bone regeneration, although the construct of hASCs + PHB-HV in xeno-free conditions improved scaffold vascularisation representing a strategy potentially promising for other tissue engineering applications.

Secretome Conveys the Protective Effects of ASCs: Therapeutic Potential Following Hemorrhagic Shock?

OBJECTIVES

We tested whether resuscitation supplemented with rat adipose-derived stem cells (ASCs) or secretome (conditioned media) of ASCs can ameliorate inflammation, cell/organ injury, and/or improve outcome after hemorrhagic traumatic shock (HTS).

INTERVENTIONS

Rats were subjected to HTS and a resuscitation protocol that mimics prehospital restrictive reperfusion followed by an adequate reperfusion phase. Twenty minutes into the restrictive reperfusion, animals received an intravenous bolus of 2 × 10 cells (ASC group) or the secretome produced by 2 × 10 ASCs/24 h (ASC-Secretome group). Controls received the vehicle (Vehicle group). All rats were observed for 28-day survival.

MEASUREMENTS AND MAIN RESULTS

HTS-induced inflammation represented by IL-6 was inhibited in the ASC (80%, P < 0.001) and in ASC-Secretome (59%, P < 0.01) group at 48 h compared with Vehicle group. At 24 h, HTS-induced liver injury reflected in plasma alanine aminotransferase was ameliorated by 36% (P < 0.001) in both the ASC and ASC-Secretome groups when compared with the Vehicle. There was no effect on kidney function and/or general cell injury markers. HTS induced a moderate 28-day mortality (18%) that was prevented (P = 0.08) in the ASC but not in the ASC-Secretome group (12%).

CONCLUSIONS

Our data suggest that the ASC-secretome supplemented resuscitation following HTS, in the absence of the stem cells, exerts anti-inflammatory and liver protective effects. Given its ease of preparation, storage, availability, and application (in contrast to the stem cells) we believe that the cell-free secretome has a better therapeutic potential in the early phase of an acute hemorrhagic shock scenario.

Modulating Mechanical Properties of Collagen-Lignin Composites

Three-dimensional matrices of collagen type I (Col I) are widely used in tissue engineering applications for its abundance in many tissues, bioactivity with many cell types, and excellent biocompatibility. Inspired by the structural role of lignin in a plant tissue, we found that sodium lignosulfonate (SLS) and an alkali-extracted lignin from switchgrass (SG) increased the stiffness of Col I gels. SLS and SG enhanced the stiffness of Col I gels from 52 to 670 Pa and 52 to 320 Pa, respectively, and attenuated shear-thinning properties, with the formulation of 1.8 mg/mL Col I and 5.0 mg/mL SLS or SG. In 2D cultures, the cytotoxicity of collagen-SLS to adipose-derived stromal cells was not observed and the cell viability was maintained over 7 days in 3D cultures. Collagen-SLS composites did not elicit immunogenicity when compared to SLS-only groups. Our collagen-SLS composites present a case that exploits lignins as an enhancer of mechanical properties of Col I without adverse cytotoxicity and immunogenicity for in vitro scaffolds or in vivo tissue repairs.

Secretome of Adipose Tissue-Derived Stem Cells (ASCs) as a Novel Trend in Chronic Non-Healing Wounds: An Overview of Experimental In Vitro and In Vivo Studies and Methodological Variables

Wound healing is a complex process with a linear development that involves many actors in a multistep timeline commonly divided into four stages: Hemostasis, inflammation, proliferation, and remodeling. Chronic non-healing wounds fail to progress beyond the inflammatory phase, thus precluding the next steps and, ultimately, wound repair. Many intrinsic or extrinsic factors may contribute to such an occurrence, including patient health conditions, age-related diseases, metabolic deficiencies, advanced age, mechanical pressure, and infections. Great interest is being focused on the adipose tissue-derived stem cell’s (ASC) paracrine activity for its potential therapeutic impact on chronic non-healing wounds. In this review, we summarize the results of in vitro and in vivo experimental studies on the pro-wound healing effects of ASC-secretome and/or extracellular vesicles (EVs). To define an overall picture of the available literature data, experimental conditions and applied methodologies are described as well as the in vitro and in vivo models chosen in the reported studies. Even if a comparative analysis of the results obtained by the different groups is challenging due to the large variability of experimental conditions, the available findings are undoubtedly encouraging and fully support the use of cell-free therapies for the treatment of chronic non-healing wounds.

Autologous adipose-derived stem cell transplantation enhances healing of wound with exposed bone in a rat model

OBJECTIVES

Soft tissue wounds with exposed bone often require extended healing times and can be associated with severe complications. We describe the ability of artificial dermis with autogenic adipose-derived stem cells (ADSCs) to promote the healing of wounds with exposed bone in a rat model.

METHODS

Adipose tissues harvested from the bilateral inguinal regions of Wistar rats were used as ADSCs. Rats were randomly divided into control and ADSC groups to investigate the efficacy of ADSC transplantation for wound healing (n = 20 per group). Soft tissue defects were created on the heads of the rats and were covered with artificial dermis with or without the seeded ADSCs. Specimens from these rats were evaluated using digital image analysis, histology, immunohistochemistry, cell labeling, and real-time reverse-transcription polymerase chain reaction (real-time RT-PCR).

RESULTS

The average global wound area was significantly smaller in the ADSC group than in the control group on days 3, 7, and 14 after surgery (p<0.05). After 14 days, the blood vessel density in the wound increased by 1.6-fold in the ADSC group compared with that in the control group (p<0.01). Real-time RT-PCR results showed higher Fgfb and Vegf expression levels at all time points, and higher Tgfb1 and Tgfb3 expression levels until 14 days after surgery in the ADSC group than in the control group (p<0.05).

CONCLUSIONS

In wounds with exposed bone, autogenic ADSCs can promote vascularization and wound healing. Use of this cell source has multiple benefits, including convenient clinical application and lack of ethical concerns.

Overexpression of CX3CR1 in Adipose-Derived Stem Cells Promotes Cell Migration and Functional Recovery After Experimental Intracerebral Hemorrhage

Stem cell therapy has emerged as a new promising therapeutic strategy for intracerebral hemorrhage (ICH). However, the efficiency of stem cell therapy is partially limited by low retention and engraftment of the delivered cells. Therefore, it’s necessary to improve the migration ability of stem cells to the injured area in order to save the costs and duration of cell preparation. This study aimed to investigate whether overexpression of CX3CR1, the specific receptor of chemokine fractalkine (FKN), in adipose-derived stem cells (ADSCs) can stimulate the cell migration to the injured area in the brain, improve functional recovery and protect against cell death following experimental ICH. ADSCs were isolated from subcutaneous adipose tissues of rats. ICH was induced by means of an injection of collagenase type VII. ELISA showed that the expression levels of fractalkine/FKN were increased at early time points, with a peak at day 3 after ICH. And it was found that different passages of ADSCs could express the chemokine receptor CX3CR1. Besides, the chemotactic movements of ADSCs toward fractalkine have been verified by transwell migration assay. ADSCs overexpressing CX3CR1 were established through lentivirus transfection. We found that after overexpression of CX3CR1 receptor, the migration ability of ADSCs was increased both in vitro and in vivo. In addition, reduced cell death and improved sensory and motor functions were seen in the mice ICH model. Thus, ADSCs overexpression CX3CR1 might be taken as a promising therapeutic strategy for the treatment of ICH.

Perspectives for Clinical Translation of Adipose Stromal/Stem Cells

Adipose stromal/stem cells (ASCs) are an ideal cell type for regenerative medicine applications, as they can easily be harvested from adipose tissue in large quantities. ASCs have excellent proliferation, differentiation, and immunoregulatory capacities that have been demonstrated in numerous studies. Great interest and investment have been placed in efforts to exploit the allogeneic use and immunomodulatory and anti-inflammatory effects of ASCs. However, bridging the gap between in vitro and in vivo studies and moving into clinical practice remain a challenge. For the clinical translation of ASCs, several issues must be considered, including how to characterise such a heterogenic cell population and how to ensure their safety and efficacy. This review explores the different phases of in vitro and preclinical ASC characterisation and describes the development of appropriate potency assays. In addition, good manufacturing practice requirements are discussed, and cell-based medicinal products holding marketing authorisation in the European Union are reviewed. Moreover, the current status of clinical trials applying ASCs and the patent landscape in the field of ASC research are presented. Overall, this review highlights the applicability of ASCs for clinical cell therapies and discusses their potential.

Adipose-derived stem cell-secreted factors promote early stage follicle development in a biomimetic matrix

Development of primary follicles in vitro benefits from a three-dimensional matrix that is enriched with paracrine factors secreted from feeder cells and mimics the in vivo environment. In this study, we investigated the role of paracrine signaling from adipose-derived stem cells (ADSCs) in supporting primary follicle development in a biomimetic poly(ethylene glycol) (PEG)-based matrix. Follicles co-cultured with ADSCs and follicles cultured in conditioned medium from ADSCs encapsulated in gels (3D CM) exhibited significantly (p < 0.01 and p = 0.09, respectively) improved survival compared to follicles cultured in conditioned medium collected from ADSCs cultured in flasks (2D CM) and follicles cultured without paracrine support. The gene expression of ADSCs suggested that the stem cells maintained their multipotency in the 3D PEG environment over the culture period, regardless of the presence of the follicles, while under 2D conditions the multipotency markers were downregulated. The differences in cytokine signatures of follicles exposed to 3D and 2D ADSC paracrine factors suggest that early cytokine interactions are key for follicle survival. Taken together, the biomimetic PEG scaffold provides a three-dimensional, in vivo-like environment to induce ADSCs to secrete factors which promote early stage ovarian follicle development and survival.

Stem Cell Therapy

Stem cell therapy has tremendous potential for clinical application in the treatment of a variety of diseases in veterinary medicine. Based on the known desirable immunomodulatory properties of mesenchymal stem cells, this therapy has potential for treatment of a variety of renal diseases. This review details our current understanding of stem cell biology and proposed mechanism of action as applicable to renal disease. Studies performed in chronic kidney disease clinical trials and models of acute kidney injury are summarized with the goal of providing an overview of the current status of this treatment modality and its potential for the future.

A phase II randomized clinical trial for the treatment of recalcitrant chronic leg ulcers using centrifuged adipose tissue containing progenitor cells

BACKGROUND AIMS

Preclinical and observational reports indicate that adipose tissue (AT) is a safe and promising tool to treat non-healing venous leg ulcers (VLUs).

METHODS

From an initial cohort of 38 patients, 16 patients affected by non-healing VLUs were randomly allocated to the experimental arm (5 men and 3 women) and control arm (5 men and 3 women). In the experimental arm, wounds were treated by debridement, centrifuged adipose tissue (CAT), advanced dressings and compression. No experimental treatment (CAT) was administered to the control arm. We investigated the functional and the immunophenotypical features of the harvested CAT-derived stem cells. The primary outcome measures were healing time and safety of the cell treatment. Secondary outcomes were pain evaluated by numeric rating scale (NRS), complete wound healing at 24 weeks by Margolis Index and wound-healing process expressed in square centimeters per week. The various immunophenotypic and functional characteristics of CAT-derived stem cells were then correlated with the clinical outcomes.

RESULTS

No major adverse events were recorded. The healing time was significantly faster by applying CAT, 17.5 ± 7.0 weeks versus 24.5 ± 4.9 weeks recorded in the control arm (P < 0.036). NRS dropped after the first week to 2.7 ± 2.0 in the experimental arm versus 6.6 ± 3.0 in the control group (P < 0.01). The rate of healing at the 24th week was not significantly different between arms. Interestingly, we found a strong reverse correlation between the percent of CD34⁺/CD45^- non-hematopoietic cells, respectively, with the healing time (r = -0.894, P < 0.041) and NRS (r = -0.934, P < 0.020).

CONCLUSIONS

CAT is safe and may accelerate healing time in VLUs as well as reduce wound pain. The percentage of CD34⁺/CD45^- cells in stromal vascular fraction (SVF) seems to be a predictive biomarker of successful CAT treatment in these patients.

Regenerative Potential and Inflammation-Induced Secretion Profile of Human Adipose-Derived Stromal Vascular Cells Are Influenced by Donor Variability and Prior Breast Cancer Diagnosis

Adipose tissue contains a heterogeneous population of stromal vascular fraction (SVF) cells that work synergistically with resident cell types to enhance tissue healing. Ease of access and processing paired with therapeutic promise make SVF cells an attractive option for autologous applications in regenerative medicine. However, inherent variability in SVF cell therapeutic potential from one patient to another hinders prognosis determination for any one person. This study investigated the regenerative properties and inflammation responses of thirteen, medically diverse human donors. Using non-expanded primary lipoaspirate samples, SVF cells were assessed for robustness of several parameters integral to tissue regeneration, including yield, viability, self-renewal capacity, proliferation, differentiation potential, and immunomodulatory cytokine secretion. Each parameter was selected either for its role in regenerative potential, defined here as the ability to heal tissues through stem cell repopulation and subsequent multipotent differentiation, or for its potential role in wound healing through trophic immunomodulatory activity. These data were then analyzed for consistent and predictable patterns between and across measurements, while also investigating the influence of the donors' relevant medical histories, particularly if the donor was in remission following breast cancer treatment. Analyses identified positive correlations among the expression of three cytokines: interleukin (IL)-6, IL-8, and monocyte chemoattractant protein (MCP)-1. The expression of these cytokines also positively related to self-renewal capacity. These results are potentially relevant for establishing expectations in both preclinical experiments and targeted clinical treatment strategies that use stem cells from patients with diverse medical histories.

Neonatal overfeeding impairs differentiation potential of mice subcutaneous adipose mesenchymal stem cells

Nutritional changes in the development (intrauterine life and postnatal period) may trigger long-term pathophysiological complications such as obesity and cardiovascular disease. Metabolic programming leads to organs and tissues modifications, including adipose tissue, with increased lipogenesis, production of inflammatory cytokines, and decreased glucose uptake. However, stem cells participation in adipose tissue dysfunctions triggered by overfeeding during lactation has not been elucidated. Therefore, this study was the first to evaluate the effect of metabolic programming on adipose mesenchymal stem cells (ASC) from mice submitted to overfeeding during lactation, using the litter reduction model. Cells were evaluated for proliferation capacity, viability, immunophenotyping, and reactive oxygen species (ROS) production. The content of UCP-2 and PGC1-α was determined by Western Blot. ASC differentiation potential in adipogenic and osteogenic environments was also evaluated, as well the markers of adipogenic differentiation (PPAR-γ and FAB4) and osteogenic differentiation (osteocalcin) by RT-qPCR. Results indicated that neonatal overfeeding does not affect ASC proliferation, ROS production, and viability. However, differentiation potential and proteins related to metabolism were altered. ASC from overfed group presented increased adipogenic differentiation, decreased osteogenic differentiation, and also showed increased PGC1-α protein content and reduced UCP-2 expression. Thus, ASC may be involved with the increased adiposity observed in neonatal overfeeding, and its therapeutic potential may be affected.

Porous tissue strands: avascular building blocks for scalable tissue fabrication

The scalability of cell aggregates such as spheroids, strands, and rings has been restricted by diffusion of nutrient and oxygen into their core. In this study, we introduce a novel concept in generating tissue building blocks with micropores, which represents an alternative solution for vascularization. Sodium alginate porogens were mixed with human adipose-derived stem cells, and loaded into tubular alginate capsules, followed by de-crosslinking of the capsules. The resultant cellular structure exhibited a porous morphology and formed cell aggregates in the form of strands, called 'porous tissue strands (pTSs).' Three-dimensional reconstructions show that pTSs were able to maintain ∼25% porosity with a high pore interconnectivity (∼85%) for 3 weeks. Owing to the porous structure, pTSs showed up-regulated cell viability and proliferation rate as compared to solid counterparts throughout the culture period. pTSs also demonstrated self-assembly capability through tissue fusion yielding larger-scale patches. In this paper, chondrogenesis and osteogenesis of pTSs were also demonstrated, where the porous microstructure up-regulated both chondrogenic and osteogenic functionalities indicated by cartilage- and bone-specific immunostaining, quantitative biochemical assessment and gene expression. These findings indicated the functionality of pTSs, which possessed controllable porosity and self-assembly capability, and had great potential to be utilized as tissue building blocks in distinct applications such as cartilage and bone regeneration.

Fat extract promotes angiogenesis in a murine model of limb ischemia: a novel cell-free therapeutic strategy

Background

The proangiogenic capacity of adipose tissue and its derivatives has been demonstrated in a variety of studies. The paracrine mechanism of the cellular component is considered to play a critical role in the regenerative properties of these tissues. However, cell-based therapy for clinical application has been hindered by limitations such as safety, immunogenicity issues, and difficulties in cell preservation, transportation, and phenotype control. In the current study, we aimed to produce a cell-free extract directly from human fat tissue and evaluate its potential therapeutic efficacy.

Methods

We developed a novel physical approach to produce a cell-free aqueous extract from human fat tissue (fat extract (FE)). The therapeutic potential of FE was investigated in the ischemic hindlimb model of nude mice. After establishment of hindlimb ischemia with ligation of the left femoral artery and intramuscular injection of FE, blood perfusion was monitored at days 0, 7, 14, 21, and 28. Tissue necrosis and capillary density were evaluated. Enzyme-linked immunosorbent assay was used to analyze the growth factors contained in FE. Moreover, the proliferation, migration, and tube formation ability were tested on human umbilical vein endothelial cells (HUVECs) in vitro when treated with FE. The proangiogenic ability of FE was further assessed in an in-vivo Matrigel plug assay.

Results

FE was prepared and characterized. The intramuscular injection of FE into the ischemic hindlimb of mice attenuated severe limb loss and increased blood flow and capillary density of the ischemic tissue. Enzyme-linked immunosorbent assay showed that FE contained high levels of various growth factors. When added as a cell culture supplement, FE promoted HUVEC proliferation, migration, and tube formation ability in a dose-dependent manner. The subcutaneous injection of Matrigel infused with FE enhanced vascular formation.

Conclusions

We developed a novel cell-free therapeutic agent, FE, produced from human adipose tissue. FE was able to attenuate ischemic injury and stimulate angiogenesis in ischemic tissues. This study indicates that FE may represent a novel cell-free therapeutic agent in the treatment of ischemic disorders.

Deficient primary cilia in obese adipose-derived mesenchymal stem cells: obesity, a secondary ciliopathy?

Obesity alters the composition, structure and function of adipose tissue, characterized by chronic inflammation, insulin resistance and metabolic dysfunction. Adipose-derived mesenchymal stem cells (ASCs) are responsible for cell renewal, spontaneous repair and immunomodulation in adipose tissue. Increasing evidence highlights that ASCs are deficient in obesity, and the underlying mechanisms are not well understood. We have recently shown that obese ASCs have defective primary cilia, which are shortened and unable to properly respond to stimuli. Impaired cilia compromise ASC functions. This work suggests an intertwined connection of obesity, defective cilia and dysfunctional ASCs. We have here discussed the current data regarding defective cilia in various cell types in obesity. Based on these observations, we hypothesize that obesity, a systemic chronic metainflammation, could impair cilia in diverse ciliated cells, like pancreatic islet cells, stem cells and hypothalamic neurons, making these critical cells dysfunctional by shutting down their signal sensors and transducers. In this context, obesity may represent a secondary form of ciliopathy induced by obesity-related inflammation and metabolic dysfunction. Reactivation of ciliated cells might be an alternative strategy to combat obesity and its associated diseases.

Insight into the development of obesity: functional alterations of adipose-derived mesenchymal stem cells

Obesity is associated with a variety of disorders including cardiovascular diseases, diabetes mellitus and cancer. Obesity changes the composition and structure of adipose tissue, linked to pro-inflammatory environment, endocrine/metabolic dysfunction, insulin resistance and oxidative stress. Adipose-derived mesenchymal stem cells (ASCs) have multiple functions like cell renewal, spontaneous repair and homeostasis in adipose tissue. In this review article, we have summarized the recent data highlighting that ASCs in obesity are defective in various functionalities and properties including differentiation, angiogenesis, motility, multipotent state, metabolism and immunomodulation. Inflammatory milieu, hypoxia and abnormal metabolites in obese tissue are crucial for impairing the functions of ASCs. Further work is required to explore the precise molecular mechanisms underlying its alterations and impairments. Based on these data, we suggest that deregulated ASCs, possibly also other mesenchymal stem cells, are important in promoting the development of obesity. Restoration of ASCs/mesenchymal stem cells might be an additional strategy to combat obesity and its associated diseases.

Adipose Tissue-Derived Stromal Cells for Wound Healing

Skin as the outer layer covers the body. Wounds can affect this vital organ negatively and disrupt its functions. Wound healing as a biological process is initiated immediately after an injury. This process consists of three stages: inflammation, proliferation, remodeling. Generally, these three stages occur continuously and timely. However, some factors such as infection, obesity and diabetes mellitus can interfere with these stages and impede the normal healing process which results in chronic wounds. Financial burden on both patients and health care systems, negative biologic effect on the patient's general health status and reduction in quality of life are a number of issues which make chronic wounds as a considerable challenge. During recent years, along with advances in the biomedical sciences, various surgical and non-surgical therapeutic methods have been suggested. All of these suggested treatments have their own advantages and disadvantages. Recently, cell-based therapies and regenerative medicine represent promising approaches to wound healing. Accordingly, several types of mesenchymal stem cells have been used in both preclinical and clinical settings for the treatment of wounds. Adipose-derived stromal cells are a cost-effective source of mesenchymal stem cells in wound management which can be easily harvest from adipose tissues through the less invasive processes with high yield rates. In addition, their ability to secrete multiple cytokines and growth factors, and differentiation into skin cells make them an ideal cell type to use in wound treatment. This is a concise overview on the application of adipose-derived stromal cells in wound healing and their role in the treatment of chronic wounds.

Isolating and Characterizing Adipose-Derived Stem Cells

The research and application of regeneration medicine will require a reliable source of stem cells. Adipose tissue has proven to be an easily accessible and rich source of adult stem cells, termed adipose-derived stem cells (ASCs). ASCs have the most important advantage over stem cells from other available sources. There is no other human tissue as abundant as adipose tissue, making it possible to isolate adequate numbers of ASCs for potential clinical applications. Here, we describe detailed methods for isolating and characterizing ASCs. These procedures can be applied to adipose tissue not only for humans but also for other species.

Concise Review: Cancer Cells, Cancer Stem Cells, and Mesenchymal Stem Cells: Influence in Cancer Development

Tumors are composed of different types of cancer cells that contribute to tumor heterogeneity. Among these populations of cells, cancer stem cells (CSCs) play an important role in cancer initiation and progression. Like their stem cells counterpart, CSCs are also characterized by self-renewal and the capacity to differentiate. A particular population of CSCs is constituted by mesenchymal stem cells (MSCs) that differentiate into cells of mesodermal characteristics. Several studies have reported the potential pro-or anti-tumorigenic influence of MSCs on tumor initiation and progression. In fact, MSCs are recruited to the site of wound healing to repair damaged tissues, an event that is also associated with tumorigenesis. In other cases, resident or migrating MSCs can favor tumor angiogenesis and increase tumor aggressiveness. This interplay between MSCs and cancer cells is fundamental for cancerogenesis, progression, and metastasis. Therefore, an interesting topic is the relationship between cancer cells, CSCs, and MSCs, since contrasting reports about their respective influences have been reported. In this review, we discuss recent findings related to conflicting results on the influence of normal and CSCs in cancer development. The understanding of the role of MSCs in cancer is also important in cancer management. Stem Cells Translational Medicine 2017;6:2115-2125.

Paracrine Potential of the Human Adipose Tissue-Derived Stem Cells to Modulate Balance between Matrix Metalloproteinases and Their Inhibitors in the Osteoarthritic Cartilage In Vitro

Adipose tissue represents an abundant source of stem cells. Along with anti-inflammatory effects, ASC secrete various factors that may modulate metabolism of extracellular matrix in osteoarthritic (OA) cartilage, suggesting that the presence of ASC could be advantageous for OA cartilage due to the recovery of homeostasis between matrix metalloproteinases (MMPs) and their tissue inhibitors of metalloproteinases (TIMPs). To evaluate these effects, cartilage explants (CE) were cocultured with ASC for 3 and 7 days under stimulation with or without IL-1β. The pattern of gene expression in CE was modified by ASC, including the upregulation of COL1A1 and COL3A1 and the downregulation of MMP13 and COL10A1. The production of MMP-1, MMP-3, and MMP-13 by ASC was not significant; moreover, cocultures with ASC reduced MMP-13 production in CE. In conclusion, active production of TIMP-1, TIMP-2, TIMP-3, IL-6, IL-8, and gelatinases MMP-2 and MMP-9 by ASC may be involved in the extracellular matrix remodelling, as indicated by the altered expression of collagens, the downregulated production of MMP-13, and the reduced chondrocyte apoptosis in the cocultured CE. These data suggest that ASC modulated homeostasis of MMPs/TIMPs in degenerated OA cartilage in vitro and might be favourable in case of the intra-articular application of ASC therapy for the treatment of OA.

Stromal vascular fraction cells for the treatment of critical limb ischemia: a pilot study

BACKGROUND

Cell-based therapy is being explored as an alternative treatment option for critical limb ischemia (CLI), a disease associated with high amputation and mortality rates and poor quality of life. However, therapeutic potential of uncultured adipose-derived stromal vascular fraction (SVF) cells has not been evaluated as a possible treatment. In this pilot study, we investigated the efficacy of multiple injections of autologous uncultured adipose-derived SVF cells to treat patients with CLI.

METHODS

This study included 15 patients, from 35 to 77 years old, with rest pain and ulceration. SVF cells were injected once or twice in the ischemic limb along the arteries. Digital subtraction angiography was performed before and after cell therapy. The clinical follow up was carried out for the subsequent 12 months after the beginning of the treatment.

RESULTS

Multiple intramuscular SVF cell injections caused no complications during the follow-up period. Clinical improvement occurred in 86.7% of patients. Two patients required major amputation, and the amputation sites healed completely. The rest of patients achieved a complete ulcer healing, pain relief, improved ankle-brachial pressure index and claudication walking distance, and had ameliorated their quality of life. Digital subtraction angiography performed before and after SVF cell therapy showed formation of numerous vascular collateral networks across affected arteries.

CONCLUSION

Results of this pilot study demonstrate that the multiple intramuscular SVF cell injections stimulate regeneration of injured tissue and are effective alternative to achieve therapeutic angiogenesis in CLI patients who are not eligible for conventional treatment. Trial registration number at ISRCTN registry, ISRCTN13001382. Retrospectively registered at 26/04/2017.

Role of Epicardial Adipose Tissue in Health and Disease: A Matter of Fat?

Epicardial adipose tissue (EAT) is a small but very biologically active ectopic fat depot that surrounds the heart. Given its rapid metabolism, thermogenic capacity, unique transcriptome, secretory profile, and simply measurability, epicardial fat has drawn increasing attention among researchers attempting to elucidate its putative role in health and cardiovascular diseases. The cellular crosstalk between epicardial adipocytes and cells of the vascular wall or myocytes is high and suggests a local role for this tissue. The balance between protective and proinflammatory/profibrotic cytokines, chemokines, and adipokines released by EAT seem to be a key element in atherogenesis and could represent a future therapeutic target. EAT amount has been found to predict clinical coronary outcomes. EAT can also modulate cardiac structure and function. Its amount has been associated with atrial fibrillation, coronary artery disease, and sleep apnea syndrome. Conversely, a beiging fat profile of EAT has been identified. In this review, we describe the current state of knowledge regarding the anatomy, physiology and pathophysiological role of EAT, and the factors more globally leading to ectopic fat development. We will also highlight the most recent findings on the origin of this ectopic tissue, and its association with cardiac diseases. © 2017 American Physiological Society. Compr Physiol 7:1051-1082, 2017.

Delivered adipose-derived stromal cells improve host-derived adipose tissue formation in composite constructs in vivo

OBJECTIVES/HYPOTHESIS

Adipose tissue engineering aims to provide functional tissue surrogates for the restoration of soft tissue defects and contour deformities in the face. Many studies involve the delivery of cells; however, the impact and the exact role of the implanted cells is not yet fully elucidated.

STUDY DESIGN

Animal research.

METHODS

In this study, we used a mouse model for the development of volume-stable adipose tissue using polyurethane scaffolds combined with a long-term stable fibrin gel and adipose-derived stromal cells to investigate the influence of cell delivery on tissue development.

RESULTS

After 12 weeks in vivo, the emerging tissue in these constructs was shown to be exclusively of host origin by human-specific vimentin staining. Comparison of unseeded versus seeded scaffolds revealed a significant effect of the delivered cells on adipose tissue development as shown by histological staining and histomorphometric quantification of adipocytes, whereas blood vessel formation was not affected by delivery of adipose-derived stromal cells at this time point.

CONCLUSIONS

This is evidence for an indirect action of the implanted cells, providing a proadipogenic microenvironment within constructs, which was further boosted by adipogenic precultivation of the seeded constructs. Especially in peripheral areas of the constructs, the number of adipocytes was significantly elevated in seeded scaffolds compared to nonseeded controls, suggesting that the implanted cells likely triggered the invasion and differentiation of host cells. This is supported by the fact that the provision of a fat rich environment (by coverage of the constructs with a fat flap upon implantation) additionally stimulated adipose tissue formation.

LEVEL OF EVIDENCE

NA. Laryngoscope, 127:E428-E436, 2017.

Infrapatellar fat pad-derived mesenchymal stromal cells from osteoarthritis patients: In vitro genetic stability and replicative senescence

Different sources of mesenchymal stromal cells can be considered for regenerative medicine applications. Here we analyzed human adipose-derived stromal cells from infrapatellar fat pad (IFPSC) of osteoarthritis patients, representing a very interesting candidate for cartilage regeneration. No data are available concerning IFPSC stability after in vitro expansion. Indeed, replicative potential and multipotency progressively decrease during culture passages while DNA damage and cell senescence increase, thus possibly affecting clinical applications. To investigate whether in vitro expansion influences the genetic stability and replicative senescence of IFPSC, we performed long-term cultures and comparatively analyzed cells at different culture passages. Stromal vascular fraction was harvested from infrapatellar fat pad of 11 osteoarthritis patients undergoing knee replacement surgery. Cell recovery, growth kinetics, surface marker profile, and differentiation ability in inductive culture conditions were recorded. Genetic integrity maintenance was estimated by microsatellite instability analysis and mismatch repair gene expression, whereas telomere length and telomerase activity were assessed to evaluate replicative senescence. Anchorage-dependent growth was tested by soft agar culture. IFPSC displayed a phenotype similar to mesenchymal stromal cells from subcutaneous fat and showed differentiation ability. No microsatellite instability was documented even at advanced culture times in accordance to a sustained expression of mismatch repair genes, thus highlighting stability of short repeated sequences in the genome. No significant telomere attrition nor telomerase activity were documented during culture and cells did not lose anchorage-dependent growth ability. The presented data support the suitability and safety of in vitro expanded IFPSC from osteoarthritis patients for applications in regenerative medicine approaches. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1029-1037, 2017.

Enzymatic in situ formed hydrogel from gelatin-tyramine and chitosan-4-hydroxylphenyl acetamide for the co-delivery of human adipose-derived stem cells and platelet-derived growth factor towards vascularization

An injectable, in situ forming hydrogel system capable of co-delivering human adipose-derived stem cells (hADSC) and platelet-derived growth factor (PDGF) was investigated as a new system for tissue engineering, envisaged to support vascularization. The system consists of tyramine-conjugated gelatin and hydroxyphenyl acetamide chitosan derivative. Both are soluble and stable at physiologic conditions, which is a key factor for retaining viable cells and active growth factor. In situ gelation involved enzymatic crosslinking using horseradish peroxidase as a catalyst and hydrogen peroxide as an oxidant. Gel formation occurred within 30-90 s by controlling the concentration of polymers. PDGF release showed adequate release kinetics within the intended period of time and hADSC showed good compatibility with the hydrogel formulation based on the in vitro assay and subcutaneous implantation into BALB/c-nu/nu nude female mice. Immunohistochemical analysis confirmed viability of delivered hADSC. Histological analysis showed no immune reaction and confirmed blood vessel formation. The results implicate the hydrogel as a promising delivery vehicle or carrier of both cell and growth factor, which support vascularization for tissue engineering applications.

Modeling Stem Cell Myogenic Differentiation

The process of stem cell myogenesis (transformation into skeletal muscle cells) includes several stages characterized by the expression of certain combinations of myogenic factors. The first part of this process is accompanied by cell division, while the second part is mainly associated with direct differentiation. The mechanical cues are known to enhance stem cell myogenesis, and the paper focuses on the stem cell differentiation under the condition of externally applied strain. The process of stem cell myogenic differentiation is interpreted as the interplay among transcription factors, targeted proteins and strain-generated signaling molecule, and it is described by a kinetic multi-stage model. The model parameters are optimally adjusted by using the available data from the experiment with adipose-derived stem cells subjected to the application of cyclic uniaxial strains of the magnitude of 10%. The modeling results predict the kinetics of the process of myogenic differentiation, including the number of cells in each stage of differentiation and the rates of differentiation from one stage to another for different strains from 4% to 16%. The developed model can help better understand the process of myogenic differentiation and the effects of mechanical cues on stem cell use in muscle therapies.

Human adipose stem cell differentiation is highly affected by cancer cells both in vitro and in vivo: implication for autologous fat grafting

Recent studies showed that mesenchymal stem cells derived from adipose tissue can promote tumour progression, raising some concerns regarding their use in regenerative medicine. In this context, we co-cultured either SAOS2 osteosarcoma or MCF7 breast cancer cells with human adipose stem cells (hASCs), in order to evaluate potential effects of cancer cells on hASCs differentiation, in vitro and in vivo. In this study we observed that both SAOS2 and MCF7 cell lines induced an increase in hASCs proliferation, compared to hASCs alone, but, surprisingly, neither changes in the expression of CD90, CD29, CD324 and vimentin, nor variations in the Twist and Slug mRNAs were detectable. Noteworthy, SAOS2 and MCF7 cells induced in hASCs an upregulation of CD34 expression and stemness genes, including OCT3/4, Nanog, Sox2 and leptin, and a decrease in angiogenic factors, including CD31, PDGFα, PDGFRα, PDGFRβ and VEGF. SMAD and pSMAD2/3 increased only in hASCs alone. After 21 days of co-culture, hASCs differentiated both in adipocytes and endothelial cells. Moreover, co-injection of MCF7 cells with hASCs led to the formation of a highly vascularized tumour. Taken together our findings suggest that mesenchymal stem cells, under tumour cell induction, do not differentiate in vitro or facilitate the angiogenesis of the tumour in vivo, thus opening interesting new scenarios in the relationship between cancer and stem cells. These findings may also lead to greater caution, when managing autologous fat grafts in cancer patients.