Arguments for a Different Regulatory Categorization and Framework for Stromal Vascular Fraction

The Role of Autologous Fat Grafting in Rhinoplasty

Rhinoplasty is one of the most popular aesthetic surgeries worldwide and often includes grafting techniques to achieve optimal results. One of these grafting techniques is autologous fat transfer, which has been used to increase volume, camouflage irregularities, and/or improve the quality of the nasal skin-soft tissue envelope. Moreover, minimally invasive approaches for altering the nasal appearance have recently increased and become known as "liquid" or "nonsurgical rhinoplasty." These nonsurgical approaches include altering the nasal appearance with filler injection to induce volumetric changes in lieu of extensive surgery. The use of fat grafting as a filler is favorable to achieve well-balanced aesthetic results without compromising the nasal skin-soft tissue envelope. This capability is partly because of the regenerative potential of fat grafts, serving to improve the quality of surrounding soft tissues. In contrast, commercial injectable fillers are inert. This article highlights the role of fat grafting in surgical and nonsurgical rhinoplasty to provide surgeons with an overview of the potential of these vastly abundant, biocompatible, and cost-effective grafts.

Non-homologous use of adipose-derived cell and tissue therapies: Osteoarthritis as a case study

Adipose tissue is widely recognized as an abundant and accessible human tissue that serves as a source of cells and extracellular matrix scaffolds for regenerative surgical applications. Increasingly, orthopedic surgeons are turning to adipose tissue as a resource in their treatment of osteoarthritis and related conditions. In the U.S., the regulatory landscape governing the orthopedic surgical utilization of autologous and allogeneic adipose tissue remains complex. This manuscript reviews the Food and Drug Administration's nomenclature and guidance regarding adipose tissue products. Additionally, it surveys recent pre-clinical and clinical trial literature relating to the application of adipose-derived cells and tissues in the treatment of osteoarthritis.

Comparison of Microfat, Nanofat, and Extracellular Matrix/Stromal Vascular Fraction Gel for Skin Rejuvenation: Basic Research and Clinical Applications

BACKGROUND

Over the past 2 decades, fat grafting has been extensively applied in the field of tissue regeneration.

OBJECTIVES

The aim of this study was to investigate the therapeutic potential of microfat, nanofat, and extracellular matrix/stromal vascular fraction gel (SVF-gel) in skin rejuvenation.

METHODS

Microfat was harvested by a cannula with multiple 0.8-mm smooth side holes and processed with a fat stirrer to remove fibers. Nanofat and SVF-gel were prepared according to previously reported methods, and their structure and viability were evaluated. Then, SVF cells from the 3 types of samples were isolated and characterized, and the cell viability was compared.

RESULTS

The microstructure of the 3 samples showed distinct differences. The microfat group showed a diameter of 100 to 120.0 μm under the microscope and presented a botryoid shape under calcein acetoxymethyl (calcein-AM)/propidium iodide staining. Scanning electron microscopy analysis showed that the microfat maintained an integral histologic structure. In the nanofat group, no viable adipocytes and no normal histologic structure were observed, but high levels of free lipids were noted. The SVF-gel group showed uniform dispersion of cells with different sizes and parts of the adipose histologic structure. Cell count and culture revealed that the number of viable SVF cells decreased distinctly in the nanofat group compared with the microfat group. In contrast, the number of viable SVF cells in the SVF-gel group increased moderately. Clinical applications with microfat showed marked improvements in skin wrinkles.

CONCLUSIONS

Microfat can preserve the integrity of the histologic structure and presents the advantages of subcutaneous volumetric restoration and improvement of skin quality in skin rejuvenation compared with the nanofat and SVF-gel.

LEVEL OF EVIDENCE: 5

Overview of current adipose-derived stem cell (ADSCs) processing involved in therapeutic advancements: flow chart and regulation updates before and after COVID-19

Adipose-derived stem cells (ADSCs) have raised big interest in therapeutic applications in regenerative medicine and appear to fulfill the criteria for a successful cell therapy. Their low immunogenicity and their ability to self-renew, to differentiate into different tissue-specific progenitors, to migrate into damaged sites, and to act through autocrine and paracrine pathways have been altogether testified as the main mechanisms whereby cell repair and regeneration occur. The absence of standardization protocols in cell management within laboratories or facilities added to the new technologies improved at patient's bedside and the discrepancies in cell outcomes and engraftment increase the limitations on their widespread use by balancing their real benefit versus the patient safety and security. Also, comparisons across pooled patients are particularly difficult in the fact that multiple medical devices are used and there is absence of harmonized assessment assays despite meeting regulations agencies and efficient GMP protocols. Moreover, the emergence of the COVID-19 breakdown added to the complexity of implementing standardization. Cell- and tissue-based therapies are completely dependent on the biological manifestations and parameters associated to and induced by this virus where the scope is still unknown. The initial flow chart identified for stem cell therapies should be reformulated and updated to overcome patient infection and avoid significant variability, thus enabling more patient safety and therapeutic efficiency. The aim of this work is to highlight the major guidelines and differences in ADSC processing meeting the current good manufacturing practices (cGMP) and the cellular therapy-related policies. Specific insights on standardization of ADSCs proceeding at different check points are also presented as a setup for the cord blood and bone marrow.

Adipose Stromal Cell Expansion and Exhaustion: Mechanisms and Consequences

Adipose tissue (AT) is comprised of a diverse number of cell types, including adipocytes, stromal cells, endothelial cells, and infiltrating leukocytes. Adipose stromal cells (ASCs) are a mixed population containing adipose progenitor cells (APCs) as well as fibro-inflammatory precursors and cells supporting the vasculature. There is growing evidence that the ability of ASCs to renew and undergo adipogenesis into new, healthy adipocytes is a hallmark of healthy fat, preventing disease-inducing adipocyte hypertrophy and the spillover of lipids into other organs, such as the liver and muscles. However, there is building evidence indicating that the ability for ASCs to self-renew is not infinite. With rates of ASC proliferation and adipogenesis tightly controlled by diet and the circadian clock, the capacity to maintain healthy AT via the generation of new, healthy adipocytes appears to be tightly regulated. Here, we review the contributions of ASCs to the maintenance of distinct adipocyte pools as well as pathogenic fibroblasts in cancer and fibrosis. We also discuss aging and diet-induced obesity as factors that might lead to ASC senescence, and the consequences for metabolic health.

Regenerative Cell-Based Therapies: Cutting Edge, Bleeding Edge, and Off the Edge

With the emergence of cell-based therapies as viable treatment options readily accessible to patients, the scientific community and public have raised concerns regarding consumer accessibility and regulation enforcement. Opposing viewpoints regarding regulation have emerged, and efforts to maintain the balance between promoting scientific innovation and ensuring public safety has proved challenging. To further complicate matters, there is contradictory information regarding the clinical safety and efficacy of cell-based treatments. Herein, we outline the FDA's regulatory framework for cell-based therapies and describe what we term the cutting edge, bleeding edge, and off the edge interventions. We conclude with a new classification system for regenerative cell-based therapies intended to further aid in delineating between the clinically and scientifically sound therapies to those that compel further scientific investigation.