Qualitative and quantitative differences of adipose-derived stromal cells from superficial and deep subcutaneous lipoaspirates: a matter of fat

Adipose-Derived Stem Cells: Angiogenetic Potential and Utility in Tissue Engineering

Adipose tissue (AT) is a large and important energy storage organ as well as an endocrine organ with a critical role in many processes. Additionally, AT is an enormous and easily accessible source of multipotent cell types used in our day for all types of tissue regeneration. The ability of adipose-derived stem cells (ADSCs) to differentiate into other types of cells, such as endothelial cells (ECs), vascular smooth muscle cells, or cardiomyocytes, is used in tissue engineering in order to promote/stimulate the process of angiogenesis. Being a key for future successful clinical applications, functional vascular networks in engineered tissue are targeted by numerous in vivo and ex vivo studies. The article reviews the angiogenic potential of ADSCs and explores their capacity in the field of tissue engineering (TE).

Feasibility of adipose-derived therapies for hair regeneration: Insights based on signaling interplay and clinical overview

Dermal white adipose tissue (dWAT) is a dynamic component of the skin and closely interacts with the hair follicle. Interestingly, dWAT envelops the hair follicle during anagen and undergoes fluctuations in volume throughout the hair cycle. dWAT-derived extracellular vesicles can significantly regulate the hair cycle, and this provides a theoretical basis for utilizing adipose tissue as a feasible clinical strategy to treat hair loss. However, the amount and depth of the available literature are far from enough to fully elucidate the prominent role of dWAT in modulating the hair growth cycle. This review starts by investigating the hair cycle-coupled dWAT remodeling and the reciprocal signaling interplay underneath. Then, it summarizes the current literature and assesses the advantages and limitations of clinical research utilizing adipose-derived therapies for hair regeneration.

Mimicking lipolytic, adipogenic, and secretory capacities of human subcutaneous adipose tissue by spheroids from distinct subpopulations of adipose stromal/stem cells

Background: Adipose tissue engineering may provide 3D models for the understanding of diseases such as obesity and type II diabetes. Recently, distinct adipose stem/stromal cell (ASC) subpopulations were identified from subcutaneous adipose tissue (SAT): superficial (sSAT), deep (dSAT), and the superficial retinacula cutis (sRC). This study aimed to test these subpopulations ASCs in 3D spheroid culture induced for adipogenesis under a pro-inflammatory stimulus with lipopolysaccharide (LPS). Methods: The samples of abdominal human subcutaneous adipose tissue were obtained during plastic aesthetic surgery (Protocol 145/09). Results: ASC spheroids showed high response to adipogenic induction in sSAT. All ASC spheroids increased their capacity to lipolysis under LPS. However, spheroids from dSAT were higher than from sSAT (p = 0.0045) and sRC (p = 0.0005). Newly formed spheroids and spheroids under LPS stimulus from sSAT showed the highest levels of fatty acid-binding protein 4 (FABP4) and CCAAT/enhancer-binding protein-α (C/EBPα) mRNA expression compared with dSAT and sRC (p < 0.0001). ASC spheroids from sRC showed the highest synthesis of angiogenic cytokines such as vascular endothelial growth factor (VEGF) compared with dSAT (p < 0.0228). Under LPS stimulus, ASC spheroids from sRC showed the highest synthesis of pro-inflammatory cytokines such as IL-6 compared with dSAT (p < 0.0092). Conclusion: Distinct physiological properties of SAT can be recapitulated in ASC spheroids. In summary, the ASC spheroid from dSAT showed the greatest lipolytic capacity, from sSAT the greatest adipogenic induction, and sRC showed greater secretory capacity when compared to the dSAT. Together, all these capacities form a true mimicry of SAT and hold the potential to contribute for a deeper understanding of cellular and molecular mechanisms in healthy and unhealthy adipose tissue scenarios or in response to pharmacological interventions.

Guided Superficial Enhanced Fluid Fat Injection (SEFFI) Procedures for Facial Rejuvenation: An Italian Multicenter Retrospective Case Report

BACKGROUND

The aging process starts in the center of the face, in the periocular region and around the mouth, with a combination of volume loss, tissue descent, deepened wrinkles, and the loss of skin structure and quality. Recently, several studies have demonstrated the efficacy of therapies based on autologous adipose tissue grafting, which leverages the properties of stromal vascular fraction (SVF) and adipose-derived mesenchymal stem cells (ADSCs) to accelerate the regenerative processes of the skin. This study aims to verify the ability of guided superficial enhanced fluid fat injection (SEFFI) in the facial area to correct volume loss and skin aging, proving that this standardized procedure has a very low rate of complications.

METHODS

We retrospectively collected data from 2365 procedures performed in Italian centers between 2019 and 2021. Guided SEFFI was performed alone or combined with cosmetic treatments, including the use of hyaluronic acid filler, suspension threads, synthetic calcium hydroxylapatite, botulin toxin, and microneedling.

RESULTS

guided SEFFI was used alone in more than 60% of the patients and in all facial areas. In about one-tenth of the patients, guided SEFFI was combined with a botulin toxin treatment or hyaluronic acid filling. Other procedures were used more rarely. Ecchymosis in the donor or injection sites was the most frequent adverse event but was only observed in 14.2% and 38.6% of the patients, respectively.

CONCLUSIONS

The guided SEFFI technique is standardized and minimally invasive, leading to very few complications. It constitutes a promising antiaging medical treatment that combines effectiveness, safety, and simplicity.

Stromal Vascular Fraction Obtained From Subcutaneous Adipose Tissue: Ex-Obese and Older Population as Main Clinical Targets

INTRODUCTION

Human adipose tissue contains a heterogeneous and synergistic mixture of cells called stromal vascular fraction (SVF) with highly proliferative and angiogenic properties, conferring promising applicability in the field of regenerative medicine. This study aims to investigate if age, body mass index (BMI), history of obesity and massive weight loss, and harvest site are related to SVF cell marker expression.

METHODS

A total of 26 samples of subcutaneous adipose tissue were harvested from patients admitted to the Plastic and Reconstructive department in University Hospital Center of São João, Porto, Portugal, for body contouring surgery. The percentage of cells expressing CD31, CD34, CD45, CD73, CD90, and CD105 was assessed and compared with patient's age, BMI, history of obesity and massive weight loss (ex-obese group), and harvest site.

RESULTS

In the ex-obese group, a significantly higher number of cells expressing CD90 (P = 0.002) was found. BMI, harvest site, and age appear to have no association with SVF subpopulations.

CONCLUSIONS

This study suggests that ex-obese patients have a higher percentage of SVF cells expressing CD90, which correlates with higher proliferative and angiogenic rates. The effect of former obesity and massive weight loss on the expression of CD90 is a new and relevant finding because it makes this population a suitable candidate for reconstructive and aesthetic surgery and other fields of regenerative medicine. The use of SVF appears also promising in older patients because no negative correlation between increasing age and different cell markers expression was found.

Cartilage 3D bioprinting for rhinoplasty using adipose-derived stem cells as seed cells: Review and recent advances

Nasal deformities due to various causes affect the aesthetics and use of the nose, in which case rhinoplasty is necessary. However, the lack of cartilage for grafting has been a major problem and tissue engineering seems to be a promising solution. 3D bioprinting has become one of the most advanced tissue engineering methods. To construct ideal cartilage, bio-ink, seed cells, growth factors and other methods to promote chondrogenesis should be considered and weighed carefully. With continuous progress in the field, bio-ink choices are becoming increasingly abundant, from a single hydrogel to a combination of hydrogels with various characteristics, and more 3D bioprinting methods are also emerging. Adipose-derived stem cells (ADSCs) have become one of the most popular seed cells in cartilage 3D bioprinting, owing to their abundance, excellent proliferative potential, minimal morbidity during harvest and lack of ethical considerations limitations. In addition, the co-culture of ADSCs and chondrocytes is commonly used to achieve better chondrogenesis. To promote chondrogenic differentiation of ADSCs and construct ideal highly bionic tissue-engineered cartilage, researchers have used a variety of methods, including adding appropriate growth factors, applying biomechanical stimuli and reducing oxygen tension. According to the process and sequence of cartilage 3D bioprinting, this review summarizes and discusses the selection of hydrogel and seed cells (centered on ADSCs), the design of printing, and methods for inducing the chondrogenesis of ADSCs.

Efficacy of Human Embryonic Stem Cells Compared to Adipose Tissue-Derived Human Mesenchymal Stem/Stromal Cells for Repair of Murine Post-Stenotic Kidneys

Clinical translation of mesenchymal stem/stromal cell (MSC) therapy has been impeded by the heterogenous nature and limited replicative potential of adult-derived MSCs. Human embryonic stem cell-derived MSCs (hESC-MSCs) that differentiate from immortal cell lines are phenotypically uniform and have shown promise in-vitro and in many disease models. Similarly, adipose tissue-derived MSCs (MSC(AT)) possess potent reparative properties. How these two cell types compare in efficacy, however, remains unknown. We randomly assigned mice to six groups (n = 7-8 each) that underwent unilateral RAS or a sham procedure (3 groups each). Two weeks post-operation, each mouse was administered either vehicle, MSC(AT)s, or hESC-MSCs (5 × 105 cells) into the aorta. Mice were scanned with micro-MRI to determine renal hemodynamics two weeks later and kidneys then harvested. hESC-MSCs and MSC(AT)s were similarly effective at lowering systolic blood pressure. However, MSC(AT)s more robustly increased renal perfusion, oxygenation, and glomerular filtration rate in the post-stenotic kidney, and more effectively mitigated tubular injury, fibrosis, and vascular remodeling. These observations suggest that MSC(AT) are more effective than hESC-MSC in ameliorating kidney dysfunction and tissue injury distal to RAS. Our findings highlight the importance of tissue source in selection of MSCs for therapeutic purposes and underscore the utility of cell-based therapy for kidney disease.

Micro-fragmented and nanofat adipose tissue derivatives: In vitro qualitative and quantitative analysis

Introduction: Adipose tissue is widely exploited in regenerative medicine thanks to its trophic properties, mainly based on the presence of adipose-derived stromal cells. Numerous devices have been developed to promote its clinical use, leading to the introduction of one-step surgical procedures to obtain minimally manipulated adipose tissue derivatives. However, only a few studies compared their biological properties. This study aimed to characterize micro-fragmented (MAT) and nanofat adipose tissue (NAT) obtained with two different techniques. Methods: MAT, NAT and unprocessed lipoaspirate were collected from surgical specimens. RNA extraction and collagenase isolation of stromal vascular fraction (SVF) were performed. Tissue sections were analysed by histological and immunohistochemical (collagen type I, CD31, CD34 and PCNA) staining to assess tissue morphology and cell content. qPCR was performed to evaluate the expression of stemness-related (SOX2, NANOG and OCT3/4), extracellular matrix (COL1A1) and inflammatory genes (IL1β, IL6 and iNOS). Furthermore, multilineage differentiation was assessed following culture in adipogenic and osteogenic media and staining with Oil Red O and Alizarin red. ASC immunophenotype was assessed by flow cytometric analysis of CD90, CD105, CD73 and CD45. Results: Histological and immunohistochemical results showed an increased amount of stroma and a reduction of adipocytes in MAT and NAT, with the latter displaying the highest content of collagen type I, CD31, CD34 and PCNA. From LA to MAT and NAT, an increasing expression of NANOG, SOX2, OCT3/4, COL1A1 and IL6 was noted, while no significant differences in terms of IL1β and iNOS emerged. No statistically significant differences were noted between NAT and SVF in terms of stemness-related genes, while the latter demonstrated a significantly higher expression of stress-related markers. SVF cells derived from all three samples (LA, MAT, and NAT) showed a similar ASC immunoprofile as well as osteogenic and adipogenic differentiation. Discussion: Our results showed that both MAT and NAT techniques allowed the rapid isolation of ASC-rich grafts with a high anabolic and proliferative potential. However, NAT showed the highest levels of extracellular matrix content, replicating cells, and stemness gene expression. These results may provide precious clues for the use of adipose tissue derivatives in the clinical setting.

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

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

Translating Material Science into Bone Regenerative Medicine Applications: State-of-The Art Methods and Protocols

In the last 20 years, bone regenerative research has experienced exponential growth thanks to the discovery of new nanomaterials and improved manufacturing technologies that have emerged in the biomedical field. This revolution demands standardization of methods employed for biomaterials characterization in order to achieve comparable, interoperable, and reproducible results. The exploited methods for characterization span from biophysics and biochemical techniques, including microscopy and spectroscopy, functional assays for biological properties, and molecular profiling. This review aims to provide scholars with a rapid handbook collecting multidisciplinary methods for bone substitute R&D and validation, getting sources from an up-to-date and comprehensive examination of the scientific landscape.

Optimization of Mesenchymal Stromal Cell (MSC) Manufacturing Processes for a Better Therapeutic Outcome

MSCs products as well as their derived extracellular vesicles, are currently being explored as advanced biologics in cell-based therapies with high expectations for their clinical use in the next few years. In recent years, various strategies designed for improving the therapeutic potential of mesenchymal stromal cells (MSCs), including pre-conditioning for enhanced cytokine production, improved cell homing and strengthening of immunomodulatory properties, have been developed but the manufacture and handling of these cells for their use as advanced therapy medicinal products (ATMPs) remains insufficiently studied, and available data are mainly related to non-industrial processes. In the present article, we will review this topic, analyzing current information on the specific regulations, the selection of living donors as well as MSCs from different sources (bone marrow, adipose tissue, umbilical cord, etc.), in-process quality controls for ensuring cell efficiency and safety during all stages of the manual and automatic (bioreactors) manufacturing process, including cryopreservation, the use of cell banks, handling medicines, transport systems of ATMPs, among other related aspects, according to European and US legislation. Our aim is to provide a guide for a better, homogeneous manufacturing of therapeutic cellular products with special reference to MSCs.

A new approach to regenerative medicine in gynecology

OBJECTIVE

To evaluate the efficacy of the injection of microfragmented adipose tissue in the treatment of women with genitourinary syndrome of menopause (GSM).

METHODS

This observational cohort study included 12 women who received one session of multiple injections of microfragmented adipose tissue using the SEFFIGYN™ medical device. Symptoms such as burning, itching, dryness, pain on penetration, pain during deep intercourse, and pain on urination were assessed before the patient's treatment (T0), after 15 days (T15), and after 5 months (5Mo) using the Numerical Rating Scale (NRS).

RESULTS

An improvement of vulvar trophism was clinically evident already 2 weeks after treatment; all symptoms were notably attenuated compared with the initial visit, as demonstrated by statistically significant reductions of the NRS scores (P = 0.003 for itching, P = 0.008 for pain on urination, and P < 0.001 for the other symptoms, Sign test). Moreover, all symptoms continued to improve over time. All patients reported a positive change in their quality of life and a resumption of sexual life.

CONCLUSION

The use of microfragmented adipose tissue in GSM is promising. Nevertheless, more studies will be fundamental to exclude a potential placebo effect and better understand the underlying molecular mechanism of action.

Clinical Application of Adipose Derived Stem Cells for the Treatment of Aseptic Non-Unions: Current Stage and Future Perspectives-Systematic Review

Fracture non-union is a challenging orthopaedic issue and a socio-economic global burden. Several biological therapies have been introduced to improve traditional surgical approaches. Among these, the latest research has been focusing on adipose tissue as a powerful source of mesenchymal stromal cells, namely, adipose-derived stem cells (ADSCs). ADSC are commonly isolated from the stromal vascular fraction (SVF) of liposuctioned hypodermal adipose tissue, and their applications have been widely investigated in many fields, including non-union fractures among musculoskeletal disorders. This review aims at providing a comprehensive update of the literature on clinical application of ADSCs for the treatment of non-unions in humans. The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Only three articles met our inclusion criteria, with a total of 12 cases analyzed for demographics and harvesting, potential manufacturing and implantation of ADSCs. The review of the literature suggests that adipose derived cell therapy can represent a promising alternative in bone regenerative medicine for the enhancement of non-unions and bone defects. The low number of manuscripts reporting ADSC-based therapies for long bone fracture healing suggests some critical issues that are discussed in this review. Nevertheless, further investigations on human ADSC therapies are needed to improve the knowledge on their translational potential and to possibly achieve a consensus on their use for such applications.

Adipose-Derived Stem Cells for Facial Rejuvenation

The interest in regenerative medicine is increasing, and it is a dynamically developing branch of aesthetic surgery. Biocompatible and autologous-derived products such as platelet-rich plasma or adult mesenchymal stem cells are often used for aesthetic purposes. Their application originates from wound healing and orthopaedics. Adipose-derived stem cells are a powerful agent in skin rejuvenation. They secrete growth factors and anti-inflammatory cytokines, stimulate tissue regeneration by promoting the secretion of extracellular proteins and secrete antioxidants that neutralize free radicals. In an office procedure, without cell incubation and counting, the obtained product is stromal vascular fraction, which consists of not only stem cells but also other numerous active cells such as pericytes, preadipocytes, immune cells, and extra-cellular matrix. Adipose-derived stem cells, when injected into dermis, improved skin density and overall skin appearance, and increased skin hydration and number of capillary vessels. The main limitation of mesenchymal stem cell transfers is the survival of the graft. The final outcomes are dependent on many factors, including the age of the patient, technique of fat tissue harvesting, technique of lipoaspirate preparation, and technique of fat graft injection. It is very difficult to compare available studies because of the differences and multitude of techniques used. Fat harvesting is associated with potentially life-threatening complications, such as massive bleeding, embolism, or clots. However, most of the side effects are mild and transient: primarily hematomas, oedema, and mild pain. Mesenchymal stem cells that do not proliferate when injected into dermis promote neoangiogenesis, that is why respectful caution should be taken in the case of oncologic patients. A longer clinical observation on a higher number of participants should be performed to develop reliable indications and guidelines for transferring ADSCs.

Cadaveric Stem Cells: Their Research Potential and Limitations

In the era of growing interest in stem cells, the availability of donors for transplantation has become a problem. The isolation of embryonic and fetal cells raises ethical controversies, and the number of adult donors is deficient. Stem cells isolated from deceased donors, known as cadaveric stem cells (CaSCs), may alleviate this problem. So far, it was possible to isolate from deceased donors mesenchymal stem cells (MSCs), adipose delivered stem cells (ADSCs), neural stem cells (NSCs), retinal progenitor cells (RPCs), induced pluripotent stem cells (iPSCs), and hematopoietic stem cells (HSCs). Recent studies have shown that it is possible to collect and use CaSCs from cadavers, even these with an extended postmortem interval (PMI) provided proper storage conditions (like cadaver heparinization or liquid nitrogen storage) are maintained. The presented review summarizes the latest research on CaSCs and their current therapeutic applications. It describes the developments in thanatotranscriptome and scaffolding for cadaver cells, summarizes their potential applications in regenerative medicine, and lists their limitations, such as donor’s unknown medical condition in criminal cases, limited differentiation potential, higher risk of carcinogenesis, or changing DNA quality. Finally, the review underlines the need to develop procedures determining the safe CaSCs harvesting and use.

Comparison of the Cytokine Profile in Mesenchymal Stem Cells from Human Adipose, Umbilical Cord, and Placental Tissues

Human mesenchymal stem cells (MSCs) can be isolated from various tissues. However, the cytokine profile in different MSC types remains unclear. In this study, MSCs were extracted from adipose, umbilical cord, and placental tissues. The surface marker expression, multilineage differentiation potential, and cytokine secretion of these cells were compared. The isolated MSCs exhibited similar morphology and surface marker expression. However, they differed with regard to their differentiation potential. Adipose-MSCs (A-MSCs) exhibited a higher potential for adipogenesis and osteogenic differentiation compared with umbilical cord-MSCs (UC-MSCs) and placental-MSCs (P-MSCs). The expression levels of 80 cytokines were detected, and the data demonstrated that the three MSC types abundantly secreted insulin-like growth factor-binding protein (IGFBP)-4, IGFBP-3, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, IGFBP-6, monocyte chemoattractant protein-1, and granulocyte colony-stimulating factor. However, the expression levels of vascular endothelial growth factor, tumor necrosis factor alpha, interleukin (IL)-6 receptor, and IL-13 in A-MSCs were higher compared with those of UC-MSCs and P-MSCs. Moreover, the expression levels of intercellular adhesion molecule-1 and growth differentiation factor 15 were lower in A-MSCs. Kyoto Encyclopedia of Genes and Genomes analysis indicated that the "adipocytokine" and the "PI3K/Akt pathways" were enriched in A-MSCs. Taken together, the results demonstrated that MSCs from different sources exhibited differences in the secretion of specific factors. A-MSCs were associated with the expression of several proangiogenic factors and may be an improved source for angiogenesis and tissue regeneration.

UK Guidelines for Lipomodelling of the Breast on behalf of Plastic, Reconstructive and Aesthetic Surgery and Association of Breast Surgery Expert Advisory Group

Lipomodelling has become increasingly popular for reconstructive, aesthetic and therapeutic indications. The guidelines summarise available evidence for indications, training, technique, audit and outcomes in lipomodelling and also highlight areas for further research.

A novel conjunctive microenvironment derived from human subcutaneous adipose tissue contributes to physiology of its superficial layer

Background

In human subcutaneous adipose tissue, the superficial fascia distinguishes superficial and deep microenvironments showing extensions called retinacula cutis. The superficial subcutaneous adipose tissue has been described as hyperplastic and the deep subcutaneous adipose tissue as inflammatory. However, few studies have described stromal-vascular fraction (SVF) content and adipose-derived stromal/stem cells (ASCs) behavior derived from superficial and deep subcutaneous adipose tissue. In this study, we analyzed a third conjunctive microenvironment: the retinacula cutis superficialis derived from superficial subcutaneous adipose tissue.

Methods

The samples of abdominal human subcutaneous adipose tissue were obtained during plastic aesthetic surgery in France (Declaration DC-2008-162) and Brazil (Protocol 145/09).

Results

The SVF content was characterized in situ by immunofluorescence and ex vivo by flow cytometry revealing a high content of pre-adipocytes rather in superficial subcutaneous adipose tissue microenvironment. Adipogenic assays revealed higher percentage of lipid accumulation area in ASCs from superficial subcutaneous adipose tissue compared with retinacula cutis superficialis (p < 0.0001) and deep subcutaneous adipose tissue (p < 0.0001). The high adipogenic potential of superficial subcutaneous adipose tissue was corroborated by an up-regulation of adipocyte fatty acid-binding protein (FABP4) compared with retinacula cutis superficialis (p < 0.0001) and deep subcutaneous adipose tissue (p < 0.0001) and of C/EBPα (CCAAT/enhancer-binding protein alpha) compared with retinacula cutis superficialis (p < 0.0001) and deep subcutaneous adipose tissue (p < 0.0001) microenvironments. Curiously, ASCs from retinacula cutis superficialis showed a higher level of adiponectin receptor gene compared with superficial subcutaneous adipose tissue (p = 0.0409), widely known as an anti-inflammatory hormone. Non-induced ASCs from retinacula cutis superficialis showed higher secretion of human vascular endothelial growth factor (VEGF), compared with superficial (p = 0.0485) and deep (p = 0.0112) subcutaneous adipose tissue and with adipogenic-induced ASCs from superficial (p = 0.0175) and deep (p = 0.0328) subcutaneous adipose tissue. Furthermore, ASCs from retinacula cutis superficialis showed higher secretion of Chemokine (C–C motif) ligand 5 (CCL5) compared with non-induced (p = 0.0029) and induced (p = 0.0089) superficial subcutaneous adipose tissue.

Conclusions

This study highlights the contribution to ASCs from retinacula cutis superficialis in their angiogenic property previously described for the whole superficial subcutaneous adipose tissue besides supporting its adipogenic potential for superficial subcutaneous adipose tissue.

Regenerative Strategy for Persistent Periprosthetic Leakage around Tracheoesophageal Puncture: Is It an Effective Long-Term Solution?

Autologous tissue-assisted regenerative procedures have been considered effective to close different types of fistula, including the leakage around tracheoesophageal puncture. The aim of this study was to retrospectively review 10 years of lipotransfer for persistent periprosthetic leakage in laryngectomized patients with voice prosthesis. Clinical records of patients who experienced periprosthetic leakage from December 2009 to December 2019 were reviewed. Patients receiving fat grafting were included. The leakage around the prosthesis was assessed with a methylene blue test. Twenty patients experiencing tracheoesophageal fistula enlargement were treated with fat grafting. At the one-month follow-up, all patients were considered improved with no leakage observed. At six months, a single injection was sufficient to solve 75% of cases (n 15), whereas 25% (n 5) required a second procedure. The overall success rate was 80% (n 16). Results remained stable for a follow-up of 5.54 ± 3.97 years. Fat grafting performed around the voice prosthesis, thanks to its volumetric and regenerative properties, is a valid and lasting option to solve persistent periprosthetic leakage.

Adipose Tissue: Understanding the Heterogeneity of Stem Cells for Regenerative Medicine

Adipose-derived stem cells (ASCs) have been increasingly used as a versatile source of mesenchymal stem cells (MSCs) for diverse clinical investigations. However, their applications often become complicated due to heterogeneity arising from various factors. Cellular heterogeneity can occur due to: (i) nomenclature and criteria for definition; (ii) adipose tissue depots (e.g., subcutaneous fat, visceral fat) from which ASCs are isolated; (iii) donor and inter-subject variation (age, body mass index, gender, and disease state); (iv) species difference; and (v) study design (in vivo versus in vitro) and tools used (e.g., antibody isolation and culture conditions). There are also actual differences in resident cell types that exhibit ASC/MSC characteristics. Multilineage-differentiating stress-enduring (Muse) cells and dedifferentiated fat (DFAT) cells have been reported as an alternative or derivative source of ASCs for application in regenerative medicine. In this review, we discuss these factors that contribute to the heterogeneity of human ASCs in detail, and what should be taken into consideration for overcoming challenges associated with such heterogeneity in the clinical use of ASCs. Attempts to understand, define, and standardize cellular heterogeneity are important in supporting therapeutic strategies and regulatory considerations for the use of ASCs.

Surgical Decision Making in Autologous Fat Grafting: An Evidence-Based Review of Techniques to Maximize Fat Survival

Autologous fat grafting is an important tool in plastic surgery and is widely used for a variety of applications, both aesthetic and reconstructive. Despite an ever-increasing list of indications and extensive research over many years into improving outcomes, fat grafting remains plagued by incomplete and often unpredictable graft survival. Decisions made at each stage of surgery can potentially contribute to ultimate success, including donor site selection and preparation, fat harvest, processing, and purification of lipoaspirate, recipient site preparation, and delivery of harvested fat to the recipient site. In this review, we examine the evidence for and against proposed techniques at each stage of fat grafting. Areas of consensus identified include use of larger harvesting and grafting cannulas and slow injection speeds to limit cell damage due to shearing forces, grafting techniques emphasizing dispersion of fat throughout the tissue with avoidance of graft pooling, and minimizing exposure of the lipoaspirate to the environment during processing. Safety considerations include use of blunt-tipped needles or cannulas to avoid inadvertent intravascular injection as well as awareness of cannula position and avoidance of danger zones such as the subgluteal venous plexus. We believe that using the evidence to guide surgical decision-making is the key to maximizing fat grafting success. Level of Evidence: 4.

Therapeutic Potential of Niche-Specific Mesenchymal Stromal Cells for Spinal Cord Injury Repair

The use of mesenchymal stem/stromal cells (MSCs) for transplant-mediated repair represents an important and promising therapeutic strategy after spinal cord injury (SCI). The appeal of MSCs has been fuelled by their ease of isolation, immunosuppressive properties, and low immunogenicity, alongside the large variety of available tissue sources. However, despite reported similarities in vitro, MSCs sourced from distinct tissues may not have comparable biological properties in vivo. There is accumulating evidence that stemness, plasticity, immunogenicity, and adaptability of stem cells is largely controlled by tissue niche. The extrinsic impact of cellular niche for MSC repair potential is therefore important, not least because of its impact on ex vivo expansion for therapeutic purposes. It is likely certain niche-targeted MSCs are more suited for SCI transplant-mediated repair due to their intrinsic capabilities, such as inherent neurogenic properties. In addition, the various MSC anatomical locations means that differences in harvest and culture procedures can make cross-comparison of pre-clinical data difficult. Since a clinical grade MSC product is inextricably linked with its manufacture, it is imperative that cells can be made relatively easily using appropriate materials. We discuss these issues and highlight the importance of identifying the appropriate niche-specific MSC type for SCI repair.

A novel method for processing adipose-derived stromal stem cells using a closed cell washing concentration device with a hollow fiber membrane module

Cell-assisted lipotransfer (CAL) is an advanced lipoinjection method that uses autologous lipotransfer with addition of a stromal vascular fraction (SVF) containing adipose-derived stromal stem cells (ASCs). The CAL procedure of manual isolation of cells from fat requires cell processing to be performed in clean environment. To isolate cells from fat without the need for a cell processing center, such as in a procedure in an operation theater, we developed a novel method for processing SVF using a closed cell washing concentration device (CCD) with a hollow fiber membrane module. The CCD consists of a sterilized closed circuit, bags and hollow fiber, semi-automatic device and the device allows removal of >99.97% of collagenase from SVF while maintaining sterility. The number of nucleated cells, ASCs and viability in SVF processed by this method were equivalent to those in SVF processed using conventional manual isolation. Our results suggest that the CCD system is as reliable as manual isolation and may also be useful for CAL. This approach will help in the development of regenerative medicine at clinics without a cell processing center.

Functional heterogeneity of mesenchymal stem cells from natural niches to culture conditions: implications for further clinical uses

Mesenchymal stem cells (MSC) are present in all organs and tissues. Several studies have shown the therapeutic potential effect of MSC or their derived products. However, the functional heterogeneity of MSC constitutes an important barrier for transferring these capabilities to the clinic. MSC heterogeneity depends on their origin (biological niche) or the conditions of potential donors (age, diseases or unknown factors). It is accepted that many culture conditions of the artificial niche to which they are subjected, such as O₂ tension, substrate and extracellular matrix cues, inflammatory stimuli or genetic manipulations can influence their resulting phenotype. Therefore, to attain a more personalized and precise medicine, a correct selection of MSC is mandatory, based on their functional potential, as well as the need to integrate all the existing information to achieve an optimal improvement of MSC features in the artificial niche.

Mesenchymal stromal cell and bone marrow concentrate therapies for musculoskeletal indications: a concise review of current literature

The interest on applying mesenchymal stromal cells (MSCs) in orthopedic disorders has risen tremendously in the last years due to scientific successes in preclinical in vitro and animal model studies. In a wide range of diseases and injuries of the musculoskeletal system, MSCs are currently under evaluation, but so far have found access to clinical use only in few cases. The current assignment is to translate the acquired knowledge into clinical practice. Therefore, this review aims at presenting a synopsis of the up-to-date status of the use of MSCs and MSC related cell products in musculoskeletal indications. Clinical studies were included, whereas preclinical and animal study data not have been considered. Most studies published so far investigate the final outcome applying bone marrow derived MSCs. In fewer trials the use of adipose tissue derived MSCs and allogenic MSCs was investigated in different applications. Although the reported results are equivocal in the current literature, the vast majority of the studies shows a benefit of MSC based therapies depending on the cell sources and the indication in clinical use. In summary, the clinical use of MSCs in patients in orthopedic indications has been found to be safe. Standardized protocols and clear definitions of the mechanisms of action and the mode and timing of application as well as further coordinated research efforts will be necessary for finally adding MSC based therapies in standard operating procedures and guidelines for the clinicians treating orthopedic disorders.

Adipose-derived stromal cells in regulation of hematopoiesis

Over the past decade, mesenchymal stromal cells (MSCs) found in the bone marrow microenvironment have been considered to be important candidates in cellular therapy. However, the application of MSCs in clinical settings is limited by the difficulty and low efficiency associated with the separation of MSCs from the bone marrow. Therefore, distinct sources of MSCs have been extensively explored. Adipose-derived stromal cells (ASCs), a cell line similar to MSCs, have been identified as a promising source. ASCs have become increasingly popular in many fields, as they can be conveniently extracted from fat tissue. This review focuses on the properties of ASCs in hematopoietic regulation and the underlying mechanisms, as well as the current applications and future perspectives in ASC-based therapy.

The Effects of Facial Lipografting on Skin Quality: A Systematic Review

BACKGROUND

Autologous lipografting for improvement of facial skin quality was first described by Coleman in 2006. The current dogma dictates that adipose tissue-derived stromal cells that reside in the stromal vascular fraction of lipograft contribute to skin rejuvenation (e.g., increased skin elasticity), a more homogenous skin color, and softening of skin texture. Nowadays, many studies have been reported on this "skin rejuvenation" effect of autologous fat grafting. This systematic review was undertaken to assess the efficacy of autologous lipografting on skin quality.

METHODS

The MEDLINE, Embase, Cochrane Central, Web of Science, and Google Scholar databases were searched for studies evaluating the effect of autologous lipografting on facial skin quality (May 11, 2018). Outcomes of interest were skin texture, color, and elasticity in addition to histologic outcomes and number of complications.

RESULTS

Nine studies were included, with 301 patients treated in total. No meta-analysis could be performed because of heterogeneity of the metrics and outcomes. Eight studies reported increased skin elasticity; improvement in skin texture; and a more homogeneous skin color after treatment with lipografting, cellular stromal vascular fraction, or nanofat. One study reported no increased skin elasticity after lipografting. Histologic improvement was seen after lipografting and adipose tissue-derived stromal cell injections. However, in general, the level of evidence of the included studies was low. No serious complications were reported.

CONCLUSION

Autologous facial lipografting and cellular stromal vascular fraction and adipose tissue-derived stromal cell injections hardly seem to improve facial skin quality but can be considered a safe procedure.

The Influence of Negative Pressure and of the Harvesting Site on the Characteristics of Human Adipose Tissue-Derived Stromal Cells from Lipoaspirates

Background

Adipose tissue-derived stromal cells (ADSCs) have great potential for cell-based therapies, including tissue engineering. However, various factors can influence the characteristics of isolated ADSCs.

Methods

We studied the influence of the harvesting site, i.e., inner thigh (n = 3), outer thigh (n = 3), outer thigh (n = 3), outer thigh (

Results

We revealed higher initial cell yields from the outer thigh region than from the abdomen region. Negative pressure did not influence the cell yields from the outer thigh region, whereas the yields from the abdomen region were higher under high negative pressure than under low negative pressure. In the subsequent passage, in general, no significant relationship was identified between the different negative pressure and ADSC characteristics. No significant difference was observed in the characteristics of thigh ADSCs and abdomen ADSCs. Only on day 1, the diameter was significantly bigger in outer thigh ADSCs than in abdomen ADSCs. Moreover, we noted a tendency of thigh ADSCs (i.e., inner thigh+outer thigh) to reach a higher cell number on day 7. Discussion. The harvesting site and negative pressure can potentially influence initial cell yields from lipoaspirates. However, for subsequent in vitro culturing and for use in tissue engineering, it seems that the harvesting site and the level of negative pressure do not have a crucial or limiting effect on basic ADSC characteristics.in vitro culturing and for use in tissue engineering, it seems that the harvesting site and the level of negative pressure do not have a crucial or limiting effect on basic ADSC characteristics.

Molecular Characterization of Lipoaspirates Used in Regenerative Head and Neck Surgery

Importance

Adipose-derived mesenchymal stem cells (ASCs) have been used commonly in regenerative medicine and increasingly for head and neck surgical procedures. Lipoaspiration with centrifugation is purported to be a mild method for the extraction of ASCs used for autologous transplants to restore tissue defects or induce wound healing. The content of ASCs, their paracrine potential, and cellular potential in wound healing have not been explored for this method to our knowledge.

Objective

To evaluate the characteristics of lipoaspirates used in reconstructive head and neck surgical procedures with respect to wound healing.

Design, Setting, and Participants

This case series study included 15 patients who received autologous fat injections in the head and neck during surgical procedures at a tertiary referral center. The study was performed from October 2017 to November 2018, and data were analyzed from October 2017 to February 2019.

Main Outcomes and Measures

Excessive material of lipoaspirates from subcutaneous abdominal fatty tissue was examined. Cellular composition was analyzed using immunohistochemistry (IHC) and flow cytometry, and functionality was assessed through adipose, osteous, and chondral differentiation in vitro. Supernatants were tested for paracrine ASC functions in fibroblast wound-healing assays. Enzyme-linked immunosorbent assay measurement of tumor necrosis factor (TNF), vascular endothelial growth factor (VEGF), stromal-derived factor 1α (SDF-1α), and transforming growth factor β3 (TGF-β3) was performed.

Results

Among the 15 study patients (8 [53.3%] male; mean [SD] age at the time of surgery, 63.0 [2.8] years), the stromal vascular fraction (mean [SE], 53.3% [4.2%]) represented the largest fraction within the native lipoaspirates. The cultivated cells were positive for CD73 (mean [SE], 99.90% [0.07%]), CD90 (99.40% [0.32%]), and CD105 (88.54% [2.74%]); negative for CD34 (2.70% [0.45%]) and CD45 (1.74% [0.28%]) in flow cytometry; and negative for CD14 (10.56 [2.81] per 300 IHC score) and HLA-DR (6.89 [2.97] per 300 IHC score) in IHC staining; they differentiated into osteoblasts, adipocytes, and chondrocytes. The cultivated cells showed high expression of CD44 (mean [SE], 99.78% [0.08%]) and CD273 (82.56% [5.83%]). The supernatants were negative for TNF (not detectable) and SDF-1α (not detectable) and were positive for VEGF (mean [SE], 526.74 [149.84] pg/mL for explant supernatants; 528.26 [131.79] pg/106 per day for cell culture supernatants) and TGF-β3 (mean [SE], 22.79 [3.49] pg/mL for explant supernatants; 7.97 [3.15] pg/106 per day for cell culture supernatants). Compared with control (25% or 50% mesenchymal stem cell medium), fibroblasts treated with ASC supernatant healed the scratch-induced wound faster (mean [SE]: control, 1.000 [0.160]; explant supernatant, 1.369 [0.070]; and passage 6 supernatant, 1.492 [0.094]).

Conclusions and Relevance

The cells fulfilled the international accepted criteria for mesenchymal stem cells. The lipoaspirates contained ASCs that had the potential to multidifferentiate with proliferative and immune-modulating properties. The cytokine profile of the isolated ASCs had wound healing-promoting features. Lipoaspirates may have a regenerative potential and an application in head and neck surgery.

Level of Evidence

NA.

Beneficial Effects of Bariatric Surgery-Induced by Weight Loss on the Proteome of Abdominal Subcutaneous Adipose Tissue

Bariatric surgery (BS) is the most effective treatment for obesity and has a positive impact on cardiometabolic risk and in the remission of type 2 diabetes. Following BS, the majority of fat mass is lost from the subcutaneous adipose tissue depot (SAT). However, the changes in this depot and functions and as well as its relative contribution to the beneficial effects of this surgery are still controversial. With the aim of studying altered proteins and molecular pathways in abdominal SAT (aSAT) after body weight normalization induced by BS, we carried out a proteomic approach sequential window acquisition of all theoretical mass spectra (SWATH-MS) analysis. These results were complemented by Western blot, electron microscopy and RT-qPCR. With all of the working tools mentioned, we confirmed that after BS, up-regulated proteins were associated with metabolism, the citric acid cycle and respiratory electron transport, triglyceride catabolism and metabolism, formation of ATP, pyruvate metabolism, glycolysis/gluconeogenesis and thermogenesis among others. In contrast, proteins with decreased values are part of the biological pathways related to the immune system. We also confirmed that obesity caused a significant decrease in mitochondrial density and coverage, which was corrected by BS. Together, these findings reveal specific molecular mechanisms, genes and proteins that improve adipose tissue function after BS characterized by lower inflammation, increased glucose uptake, higher insulin sensitivity, higher de novo lipogenesis, increased mitochondrial function and decreased adipocyte size.

International Expert Panel Consensus on Fat Grafting of the Breast

Background

Autologous fat grafting has broad applications in reconstructive and aesthetic breast surgery as a natural filler and for its regenerative purposes. Despite the widespread use of fat grafting, there remains no shared consensus on what constitutes the optimal fat grafting technique and its oncological safety. For this reason, the authors of this study have organized a Survey and an International Consensus Conference that was held at the Aesthetic Breast Meeting in Milan (December 15, 2018).

Methods

All studies on fat grafting, both for breast aesthetic and reconstructive purposes, were electronically screened. The literature review led to 17 "key questions" that were used for the Survey. The authors prepared a set of 10 "key statements" that have been discussed in a dedicated face-to-face session during the meeting.

Results

The 10 key statements addressed all the most debated topics on fat grafting of the breast. Levels of evidence for the key statements ranged from III to IV with 2 statements (20%) supported by a level of evidence III and 6 statements (60%) by level of evidence IV. Overall consensus was reached for 2 statements (20%) with >75% agreement reached for 7 statements.

Conclusions

The survey demonstrated a diversity of opinion and attitude among the panelists with regard to technique. Clear recommendations for evidence-based clinical practice for fat grafting use both in aesthetic and reconstructive breast surgery could not be defined due to the scarcity of level 1 or 2 studies.

An Overview of Principles and New Techniques for Facial Fat Grafting

Facial fat grafting is a small-volume procedure and is primarily performed for facial rejuvenation, contouring, or regenerative surgery. The unsatisfying retention rate after fat grafting, however, led to unpredictable outcomes, subsequent multiple procedures, and even some complications. A variety of methods have been proposed to enhance the results of facial fat grafting, including several established surgical principles and many possible new techniques. Adding stem cells, fat preparations, and platelet concentrates may improve the survival after fat grafting but randomized controlled clinical studies are needed to determine their safety and efficacy as well as clinical indications for each technique.

Heterogeneity in Adipose Stem Cells

Adipose stem cells (ASCs) are the basis of procedures intended for tissue regeneration. These cells are heterogeneous, owing to various factors, including the donor age, sex, body mass index, and clinical condition; the isolation procedure (liposuction or fat excision); the place from where the cells were sampled (body site and depth of each adipose depot); culture surface; type of medium (whether supplemented with fetal bovine serum or xeno-free), that affect the principal phenotypic features of ASCs. The features related to ASCs heterogeneity are relevant for the success of therapeutic procedures; these features include proliferation capacity, differentiation potential, immunophenotype, and the secretome. These are important characteristics for the success of regenerative tissue engineering, not only because of their effects upon the reconstruction and healing exerted by ASCs themselves, but also because of the paracrine signaling of ASCs and its impact on recipient tissues. Knowledge of sources of heterogeneity will be helpful in the standardization of ASCs-based procedures. New avenues of research could include evaluation of the effects of the use of more homo1geneous ASCs for specific purposes, the study of ASCs-recipient interactions in heterologous cell transplantation, and the characterization of epigenetic changes in ASCs, as well as investigations of the effect of the metabolome upon ASCs behavior in culture.

Th17 immune response to adipose tissue-derived mesenchymal stromal cells

Adipose tissue-derived mesenchymal stromal cells (ASCs) hold the promise of achieving successful immunotherapeutic results due to their ability to regulate different T-cell fate. ASCs also show significant adaptability to environmental stresses by modulating their immunologic profile. Cell-based therapy for inflammatory diseases requires a detailed understanding of the molecular relation between ASCs and Th17 lymphocytes taking into account the influence of inflammation and cell ratio on such interaction. Accordingly, a dose-dependent increase in Th17 generation was only observed in high MSC:T-cell ratio with no significant impact of inflammatory priming. IL-23 receptor (IL-23R) expression by T cells was not modulated by ASCs when compared to levels in activated T cells, while ROR-γt expression was significantly increased reaching a maximum in high (1:5) unprimed ASC:T-cell ratio. Finally, multiplex immunoassay showed substantial changes in the secretory profile of 15 cytokines involved in the Th17 immune response (IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-22, IL-21, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40, and TNF-α), which was modulated by both cell ratio and inflammatory priming. These findings suggest that Th17 lymphocyte pathway is significantly modulated by ASCs that may lead to immunological changes. Therefore, future ASC-based immunotherapy should take into account the complex and detailed molecular interactions that depend on several factors including inflammatory priming and cell ratio.

Adipose tissue-derived extracellular matrix hydrogels as a release platform for secreted paracrine factors

Fat grafting is an established clinical intervention to promote tissue repair. The role of the fat's extracellular matrix (ECM) in regeneration is largely neglected. We investigated in vitro the use of human adipose tissue‐derived ECM hydrogels as release platform for factors secreted by adipose‐derived stromal cells (ASCs). Lipoaspirates from nondiabetic and diabetic donors were decellularized. Finely powdered acellular ECM was evaluated for cell remainders and DNA content. Acellular ECM was digested, and hydrogels were formed at 37°C and their viscoelastic relaxation properties investigated. Release of ASC‐released factors from hydrogels was immune assessed, and bio‐activity was determined by fibroblast proliferation and migration and endothelial angiogenesis. Acellular ECM contained no detectable cell remainders and negligible DNA contents. Viscoelastic relaxation measurements yielded no data for diabetic‐derived hydrogels due to gel instability. Hydrogels released several ASC‐released factors concurrently in a sustained fashion. Functionally, released factors stimulated fibroblast proliferation and migration as well as angiogenesis. No difference between nondiabetic and diabetic hydrogels in release of factors was measured. Adipose ECM hydrogels incubated with released factors by ASC are a promising new therapeutic modality to promote several important wound healing‐related processes by releasing factors in a controlled way.

Regenerative and Transplantation Medicine: Cellular Therapy Using Adipose Tissue-Derived Mesenchymal Stromal Cells for Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is caused by the autoimmune targeting of pancreatic β-cells, and, in the advanced stage, severe hypoinsulinemia due to islet destruction. In patients with T1DM, continuous exogenous insulin therapy cannot be avoided. However, an insufficient dose of insulin easily induces extreme hyperglycemia or diabetic ketoacidosis, and intensive insulin therapy may cause hypoglycemic symptoms including hypoglycemic shock. While these insulin therapies are efficacious in most patients, some additional therapies are warranted to support the control of blood glucose levels and reduce the risk of hypoglycemia in patients who respond poorly despite receiving appropriate treatment. There has been a recent gain in the popularity of cellular therapies using mesenchymal stromal cells (MSCs) in various clinical fields, owing to their multipotentiality, capacity for self-renewal, and regenerative and immunomodulatory potential. In particular, adipose tissue-derived MSCs (ADMSCs) have become a focus in the clinical setting due to the abundance and easy isolation of these cells. In this review, we outline the possible therapeutic benefits of ADMSC for the treatment of T1DM.

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.

Liposuction Aspirate Fluid Adipose-Derived Stem Cell Injection and Secondary Healing in Fingertip Injury: A Pilot Study

BACKGROUND

Although fingertip injuries account for a high proportion of trauma patients, the correct surgical approach is still debated. The authors compared the traditional conservative approach and a new treatment based on the injection of liposuction aspirate fluid.

METHODS

Forty consecutive patients with a fingertip injury were dichotomized into group A (control group; conservative approach) and group B (treatment group). Group B underwent liposuction, followed by filtration of the lipoaspirate in a closed device (MyStem EVO kit), allowing the nonenzymatic separation of liposuction aspirate fluid, which was then injected at the site of injury. Objective outcomes were time for healing, strength, mobility of joint, and touch and sensory function. Subjective outcomes were cold intolerance, pain, hand disability, and aesthetic result. An aliquot of liposuction aspirate fluid was sent to the laboratory for cellular isolation and analysis by flow cytometry and in vitro differentiation assays.

RESULTS

The average healing time was 22.3 days in group B and 24.9 days in group A (p < 0.05). Eighty-five percent of group B patients and 67 percent of group A patients scored normal to diminished superficial sensibility (p < 0.05). Group A had higher pain and cold intolerance scores (p < 0.05). Group B scored greater aesthetic and disabilities outcome results (p < 0.05). The cell isolation yield was 8.3 × 10(5)/ml, with a percentage of viable cells of 74.3 percent. Flow cytometry identified a mesenchymal immunophenotype, and in vitro osteogenic and adipogenic induction confirmed the bilinear potential of the isolated cells.

CONCLUSION

This clinical study demonstrates for the first time the regenerative potential of liposuction aspirate fluid adipose-derived stem cells in a clinical application.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Autologous fat grafting: Harvesting techniques

Autologous fat grafting is widely used for soft-tissue augmentation and replacement in reconstructive and aesthetic surgery providing a biocompatible, natural and inexpensive method. Multiple approaches have been developed in the past years, varying in the location of adipose tissue donor-sites, use of wetting solutions, harvesting, processing and placing techniques. Despite many advances in this subject, the lack of standardization in the protocols and the unpredictability of the resorption of the grafted tissue pose a significant limitation for graft retention and subsequent filling. In this review, we discuss several approaches and methods described over the last years concerning the harvesting of autologous fat grafts. We focus on contents such as the best donor-site, differences between existing harvesting techniques (namely tissue resection, hand aspiration or liposuction techniques), recommended harvesting cannula diameters, pressure application and volume of wetting solution injected prior aspiration. Results and comparisons between methods tend to vary according to the outcome measured, thus posing a limitation to pinpoint the most efficient methods to apply in fat grafting. Additionally, the lack of a standard assay to determine viability or volume augmentation of fat grafting remains another limitation to obtain universally accepted grafting procedures and protocols.

•

Distinct harvesting procedures associate with different outcomes of fat graft take.

•

Flank, abdomen, thigh and knee are the more consistently used donor-sites for fat.

•

Higher vacuum pressures in liposuction are more traumatic for the tissue.

•

The tumescent technique is a safer procedure with improved aesthetic results.

•

Comparing harvesting techniques is a big challenge given the multiple variables.

Revisiting the Advances in Isolation, Characterization and Secretome of Adipose-Derived Stromal/Stem Cells

Adipose-derived stromal/stem cells (ASCs) seems to be a promising regenerative therapeutic agent due to the minimally invasive approach of their harvest and multi-lineage differentiation potential. The harvested adipose tissues are further digested to extract stromal vascular fraction (SVF), which is cultured, and the anchorage-dependent cells are isolated in order to characterize their stemness, surface markers, and multi-differentiation potential. The differentiation potential of ASCs is directed through manipulating culture medium composition with an introduction of growth factors to obtain the desired cell type. ASCs have been widely studied for its regenerative therapeutic solution to neurologic, skin, wound, muscle, bone, and other disorders. These therapeutic outcomes of ASCs are achieved possibly via autocrine and paracrine effects of their secretome comprising of cytokines, extracellular proteins and RNAs. Therefore, secretome-derivatives might offer huge advantages over cells through their synthesis and storage for long-term use. When considering the therapeutic significance and future prospects of ASCs, this review summarizes the recent developments made in harvesting, isolation, and characterization. Furthermore, this article also provides a deeper insight into secretome of ASCs mediating regenerative efficacy.

Gender and age-related cell compositional differences in C57BL/6 murine adipose tissue stromal vascular fraction

Adipose tissue is now recognized as a functional organ that contains cellular heterogeneity and diversity within anatomical depots. The stromal vascular fraction (SVF) of adipose contains endothelial progenitors, fibroblasts, lymphocytes, monocyte/macrophages, pericytes, pre-adipocytes, and stromal/stem cells, among others. In recent years, there has been a growing appreciation of the influence of age and gender in the field of stem cell biology. Yet few studies have evaluated the influence of biological age or sex on either SVF cell heterogeneity or immunophenotype. To address this issue, the current study has compared the flow cytometric characteristics between murine SVF of inguinal (iWAT), epidydimal (eWAT), and brown (BAT) adipose tissue of male and female, as well as young (6-8 week) and middle-aged (8-12 month) male C57BL/6 mice. Murine gender comparisons revealed male iWAT expressed higher percentages of leukocyte and CD34⁺ ASC-like sub-populations than female iWAT. Murine age comparisons revealed younger male iWAT, eWAT, and BAT SVF all contained a significantly higher percentage of pre-adipocytes, HSC-like cells, CD25^-, and FoxP3⁺ T-regulatory cells compared to SVF from middle-aged male mice. These findings highlight the potential contribution of biological variables on adipose-derived cell applications and experimental outcomes.

Trophic Activity and Phenotype of Adipose Tissue-Derived Mesenchymal Stem Cells as a Background of Their Regenerative Potential

There has been an increased interest in mesenchymal stem cells from adipose tissue, due to their abundance and accessibility with no ethical concerns. Their multipotent properties make them appropriate for regenerative clinical applications. It has been shown that adipose-derived stem cells (ASCs) may differ between the origin sites. Moreover, a variety of internal and external factors may affect their biological characteristics, as what we aimed to highlight in this review. It has been demonstrated that ASCs secrete multiple trophic factors that are capable of stimulating cell proliferation and differentiation and migration of various cell types. Particular attention should be given to exosomes, since it is known that they contribute to the paracrine effects of MSCs. Secretion of trophic agents by ASCs is thought to be in a greater importance for regenerative medicine applications, rather than cells engraftment to the site of injury and their differentiation ability. The surface marker profile of ASCs seems to be similar to that of the mesenchymal stem cells from bone marrow, although some molecular differences are observed. Thus, in this review, we have attempted to define trophic activity, as well as phenotypic characterization of ASCs, as crucial factors for therapeutic usage.

Comparison of intraoperative procedures for isolation of clinical grade stromal vascular fraction for regenerative purposes: a systematic review

Intraoperative application of the stromal vascular fraction (SVF) of adipose tissue requires a fast and efficient isolation procedure of adipose tissue. This review was performed to systematically assess and compare procedures currently used for the intraoperative isolation of cellular SVF (cSVF) and tissue SVF (tSVF) that still contain the extracellular matrix. Pubmed, EMBASE and the Cochrane central register of controlled trials databases were searched for studies that compare procedures for intraoperative isolation of SVF (searched 28 September 2016). Outcomes of interest were cell yield, viability of cells, composition of SVF, duration, cost and procedure characteristics. Procedures were subdivided into procedures resulting in a cSVF or tSVF. Thirteen out of 3038 studies, evaluating 18 intraoperative isolation procedures, were considered eligible. In general, cSVF and tSVF intraoperative isolation procedures had similar cell yield, cell viability and SVF composition compared to a nonintraoperative (i.e. culture laboratory-based collagenase protocol) control group within the same studies. The majority of intraoperative isolation procedures are less time consuming than nonintraoperative control groups, however. Intraoperative isolation procedures are less time-consuming than nonintraoperative control groups with similar cell yield, viability of cells and composition of SVF, and therefore more suitable for use in the clinic. Nevertheless, none of the intraoperative isolation procedures could be designated as the preferred procedure to isolate SVF. Copyright © 2017 John Wiley & Sons, Ltd.

Naturally Adipose Stromal Cell-Enriched Fat Graft: Comparative Polychromatic Flow Cytometry Study of Fat Harvested by Barbed or Blunt Multihole Cannula

Background

Fat grafts enriched with cells of the stromal vascular fraction (SVF), especially adipose-derived stromal cells (ASCs), exhibit significantly improved retention over non enriched, plain fat. Different types of liposuction cannulae may yield lipoaspirates with different subpopulations of cells. Moreover, preparation of adipose tissue for transplantation typically involves centrifugation, which creates a density gradient of fat.

Objectives

The authors sought to determine whether liposuction with a barbed or smooth cannula altered the enrichment of the SVF, and specifically ASCs, in low-density (LD) and high-density (HD) fractions of centrifuged adipose tissue.

Methods

Fat was harvested from 2 abdominal sites of 5 healthy women with a barbed or smooth multihole blunt-end cannula. After centrifugation, LD and HD fat fractions were digested with collagenase and analyzed by polychromatic flow cytometry to identify and enumerate distinct populations of cells.

Results

Overall cell yield and the number of immune cells were consistently higher in HD fractions than in LD fractions, regardless of the cannula employed. More living cells, and specifically more ASCs, populated the HD fractions of lipoaspirates obtained with a barbed cannula than with a smooth cannula.

Conclusions

In this study, lipoaspiration with a barbed cannula and isolation of the HD layer of centrifuged adipose tissue yielded maximal amounts of SVF cells, including ASCs.

Facial skin rejuvenation by autologous dermal microfat transfer in photoaged patients: Clinical evaluation and skin surface digital profilometry analysis

Cumulative long-term exposure to solar ultraviolet radiation promotes premature skin aging characterized by wrinkle formation and reduced skin elasticity. In this study, we assessed whether microfat transfer could improve dermal and subcutaneous tissue thickness loss associated with photoaging. Twenty-one patients affected by facial photoaging (photodamage grade II-IV; age range 35-62 years; 19 females, 2 males; all of Caucasian origin) were treated using minimally invasive autologous dermal white fat transfer harvested with a recently designed microcannula. The results were determined by clinical assessment and patient self-evaluation and quantified by the Antera 3D^® dermal digital device for noninvasive, objective, reliable, and accurate assessment of facial skin texture, color, and wrinkle characteristics. Compared with the pretreatment condition, the increment in soft tissue volume and improvement in skin quality and texture were assessed by a dermatologist after treatment. In addition, instrumental evaluation by digital skin profilometry of the treated areas revealed a 41% reduction in average wrinkle depth (7.29 ± 1.04 × 10^-2 mm pretreatment vs. 4.31 ± 1.16 × 10^-2 mm at 90 days posttreatment; p < 0.001), improved skin texture, more homogeneous and uniform skin color, and declined facial hemoglobin and melanin concentrations. The majority of patients (above 90%) reported improvements in self-perception. No significant complications were reported throughout the study. In conclusion, by using digital profilometry analysis as an objective and innovative tool to determine the outcome of treatment, we demonstrated that autologous microfat transfer is a safe and well-tolerated procedure with measurable beneficial effects on facial skin aging.

Adipose-derived stem cell therapies for bone regeneration

INTRODUCTION

Cell-based therapies exploit the heterogeneous and self-sufficient biological environment of stem cells to restore, maintain and improve tissue functions. Adipose-derived stem cells (ASCs) are, to this aim, promising cell types thanks to advantageous isolation procedures, growth kinetics, plasticity and trophic properties. Specifically, bone regeneration represents a suitable, though often challenging, target setting to test and apply ASC-based therapeutic strategies. Areas covered: ASCs are extremely plastic and secrete bioactive peptides that mediate paracrine functions, mediating their trophic actions in vivo. Numerous preclinical studies demonstrated that ASCs improve bone healing. Clinical trials are ongoing to validate the clinical feasibility of these approaches. This review is intended to define the state-of-the-art on ASCs, encompassing the biological features that make them suitable for bone regenerative strategies, and to provide an update on existing preclinical and clinical applications. Expert opinion: ASCs offer numerous advantages over other stem cells in terms of feasibility of clinical translation. Data obtained from in vivo experimentation are encouraging, and clinical trials are ongoing. More robust validations are thus expected to be achieved during the next few years, and will likely pave the way to optimized patient-tailored treatments for bone regeneration.

Systematic review of patient factors affecting adipose stem cell viability and function: implications for regenerative therapy

BACKGROUND

The applications for fat grafting have increased recently, within both regenerative and reconstructive surgery. Although fat harvesting, processing and injection techniques have been extensively studied and standardised, this has not had a big impact on the variability of outcome following fat grafting. This suggests a possible larger role of patient characteristics on adipocyte and adipose-derived stem cell (ADSC) viability and function. This systematic review aims to collate current evidence on the effect of patient factors on adipocyte and ADSC behaviour.

METHODS

A systematic literature review was performed using MEDLINE, Cochrane Library and EMBASE. It includes outcomes observed in in vitro analyses, in vivo animal studies and clinical studies. Data from basic science work have been included in the discussion to enhance our understanding of the mechanism behind ADSC behaviour.

RESULTS

A total of 41 papers were included in this review. Accumulating evidence indicates decreased proliferation and differentiation potential of ADSCs with increasing age, body mass index, diabetes mellitus and exposure to radiotherapy and Tamoxifen, although this was not uniformly seen across all studies. Gender, donor site preference, HIV status and chemotherapy did not show a significant influence on fat retention. Circulating oestrogen levels have been shown to support both adipocyte function and graft viability. Evidence so far suggests no significant impact of total cholesterol, hypertension, renal disease, physical exercise and peripheral vascular disease on ADSC yield.

CONCLUSIONS

A more uniform comparison of all factors highlighted in this review, with the application of a combination of tests for each outcome measure, is essential to fully understand factors that affect adipocyte and ADSC viability, as well as functionality. As these patient factors interact, future studies looking at adipocyte viability need to take them into consideration for conclusions to be meaningful. This would provide crucial information for surgeons when deciding appropriate volumes of lipoaspirate to inject, improve patient selection, and counsel patient expectations with regards to outcomes and likelihood for repeat procedures. An improved understanding will also assist in identification of patient groups that would benefit from graft enrichment and cryopreservation techniques.

Isolation of Stromal Stem Cells from Adipose Tissue

Adipose tissue has been shown to be particularly advantageous as source of mesenchymal stem cells (MSCs), because of its easy accessibility, and the possibility of obtaining stem cells in high yields. MSCs are obtained from the so-called Stromal Vascular Fraction, (SVF), exploiting their property of adhering to plastic surfaces and can be further purified by positive or negative immunomagnetic selection with appropriately chosen antibodies. These cells (Stromal Stem Cells, SSCs) can then be directly analyzed, frozen in liquid nitrogen, or expanded for further applications, e.g., for tissue engineering and regenerative medicine. The methodology described here in detail for SSCs isolated from mouse subcutaneous adipose tissue can be applied to human tissues, such as epicardium.