Basic and Clinical Evidence of an Alternative Method to Produce Vivo Nanofat

Nanofat in Plastic Reconstructive, Regenerative, and Aesthetic Surgery: A Review of Advancements in Face-Focused Applications

Nanofat is a relatively novel technique in fat grafting that has gained significant interest in the fields of regenerative medicine, aesthetic and translational research. It involves the extraction of autologous fat from a patient, which is then transformed into "nanofat", consisting of small fat particles with a diameter of less than 0.1 mm and containing high concentrations of stem cells and growth factors. This article focuses on the use of nanofat in facial rejuvenation and its potential for lipomodelling. Fat tissue is a "stem cell depot" and nanofat contains many stem cells that can differentiate into various cell types. The Lipogem technology, developed in 2013, enables the isolation of nanofat with an intact perivascular structure, utilizing the high concentration of mesenchymal stromal cells near the pericytes of the adipose vascular system. Nowadays nanofat is used primarily for cosmetic purposes particularly in rejuvenating and improving the appearance of the skin, especially the face. Indeed, it has wide applicability; it can be used to treat fine lines, wrinkles, acne scars, sun-damaged skin, scar repair, and as an alopecia treatment. However, further studies are needed to assess the long-term efficacy and safety of this technique. In conclusion, nanofat is a safe and minimally invasive option for tissue regeneration with considerable therapeutic potential. This study reviews the application and effects of nanofat in regenerative medicine and facial cosmetic surgery.

Experimental study on the influence of different aperture connectors on nanofat

BACKGROUND

Nanofat, as a derivative of adipose tissue, has gradually become a research hotspot in beauty and regenerative medicine. However, the nanofat preparation method has not yet been standardized; it remains unknown whether the aperture of the connector has any influence on the transplantation effect.

METHODS

Adipose tissue was mechanically emulsified into nanofat tissue through different connector apertures (1.0, 1.5, and 2.0 mm). Cell survival and apoptosis were measured using the volume of oil droplets, glucose transportation test, flow cytometry, cell counting kit-8 (CCK-8), wound healing assay, transwell migration assay, and fluorescence staining. The expression of adiponectin, GluT4, and PPAR-γ in nanofat-derived stem cells (NFSCs) was detected using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The fineness of nanofat tissue texture decreased with an increase in the aperture connector. The amounts of glucose transferred in the three groups (1, 1.5, and 2 mm) were 4.7 ± 0.894, 6.1 ± 1.026, and 6.9 ± 0.868 mmol/L, respectively. Flow cytometric analysis showed that the proportion of NFSCs in the 2.0 mm group was the highest (91.267±1.210%). Cell proliferation and migration abilities were stronger in the 1.5 and 2.0 mm groups. The numbers of late apoptotic and dead cells in the 2.0 mm group were significantly fewer than those in the two other groups. Expression levels of lipid-related genes were as follows: adiponectin > GluT4 > PPAR-γ in each component.

CONCLUSIONS

As nanofat is emulsified, the use of larger aperture connectors (2.0 mm) appeared to decrease the degree of adipocyte lysis and increase the biological activity of adipose tissue.

Fat obtained from plastic surgery procedures—stem cells derived from adipose tissue and their potential in technological innovation: a narrative literature review and perspective on dissociative methods

Background

Throughout its illustrious history, plastic surgery has searched for novel regenerative therapies and procedures. Recently, interest has emerged in using adipose tissue-derived stem cells (ASCs) in an ethical, easy, and reproducible manner. ASCs are generally not administered alone but as a constituent of the stromal vascular fraction (SVF) in clinical practice. Herein, we searched for innovative fat collection and ASC isolation technologies and applications and evaluated each study’s relevance to plastic surgery.

Methods

A narrative literature review was carried out using the MEDLINE/PubMed databases. Studies published from January 1993 to August 2020 and written in English, Portuguese, or Spanish were considered.

Results

The selection process yielded 33 articles for subsequent review, involving exploratory, selective, and interpretive reading, material choice, and text analysis. Twenty-three articles employed enzymatic dissociation methods to isolate ASCs, and 25 employed liposuction as the plastic surgery technique. Moreover, articles describing new devices (n = 2), techniques (n = 4), computational models (n = 1), tissue scaffolds (n = 21), and therapies and/or treatments (n = 5) were identified.

Conclusions

Given the importance of fat tissue for plastic surgery purposes, innovative ASC isolation and liposuction technologies could change how the surgeon conducts surgeries and improve surgical outcomes. Furthermore, many articles investigating tissue scaffolds demonstrate the importance of this area of research and development in plastic surgery and regenerative medicine. Continued efforts in the identified research areas will eventually bring in vivo human plastic surgery applications and regenerative medicine into the operating room. Level of evidence: Not gradable.

Research progress on preparation, mechanism, and clinical application of nanofat

Autologous adipose tissue is an ideal soft tissue filling material in theory, which has the advantages of easy access, comprehensive source, and high biocompatibility and is now widely used in clinical practice. Based on the above benefits of autologous fat, autologous fat grafting is an essential technique in plastic surgery. Conventional macrofat is used to improve structural changes after soft tissue damage or loss caused by various causes such as disease, trauma, or aging. Due to the large diameter of particles and to avoid serious complications such as fat embolism, blunt needles with larger diameters (2 mm) are required, making the macrofat grafting difficult to the deep dermis and subdermis. Nanofat grafting is a relatively new technology that has gained popularity in cosmetic surgery in recent years. Nanofat is produced by mechanical shuffling and filtration of microfat, which is harvested by liposuction. The harvesting and processing of nanofat are cost-effective as it does not require additional equipment or culture time. Unlike microfat, nanofat particles are too small to provide a notable volumizing effect. Studies have shown that nanofat contains abundant stromal vascular fraction cells and adipose-derived stem cells, which help reconstruct dermal support structures, such as collagen, and regenerate healthier, younger-looking skin. Moreover, the fluid consistency of nanofat allows application in tissue regeneration, such as scars, chronic wounds, and facial rejuvenation. This article reviews the current research progress on the preparation, mechanism, and clinical application of nanofat.

Nanofat: A therapeutic paradigm in regenerative medicine

Adipose tissue is a compact and well-organized tissue containing a heterogeneous cellular population of progenitor cells, including mesenchymal stromal cells. Due to its availability and accessibility, adipose tissue is considered a “stem cell depot.” Adipose tissue products possess anti-inflammatory, anti-fibrotic, anti-apoptotic, and immunomodulatory effects. Nanofat, being a compact bundle of stem cells with regenerative and tissue remodeling potential, has potential in translational and regenerative medicine. Considering the wide range of applicability of its reconstructive and regenerative potential, the applications of nanofat can be used in various disciplines. Nanofat behaves on the line of adipose tissue-derived mesenchymal stromal cells. At the site of injury, these stromal cells initiate a site-specific reparative response comprised of remodeling of the extracellular matrix, enhanced and sustained angiogenesis, and immune system modulation. These properties of stromal cells provide a platform for the usage of regenerative medicine principles in curbing various diseases. Details about nanofat, including various preparation methods, characterization, delivery methods, evidence on practical applications, and ethical concerns are included in this review. However, appropriate guidelines and preparation protocols for its optimal use in a wide range of clinical applications have yet to be standardized.

Not Stromal Vascular Fraction (SVF) or Nanofat, but Total Stromal-Cells (TOST): A New Definition. Systemic Review of Mechanical Stromal-Cell Extraction Techniques

The most important and greatest source in the body for regenerative cells is fat tissue. Obtaining regenerative cells from adipose tissue can be done in two ways: Enzymatic and mechanical. The regenerative cell cocktail obtained by the enzymatic method, including stem cells, is called Stromal vascular fracture (SVF). In the literature, there is no clear definition of regenerative cells obtained by mechanical method. We systematically searched the techniques and definitions for stromal cells obtained from adipose tissue by scanning different databases. To evaluate the mechanical stromal-cell isolation techniques and end products from adipose tissue. Systematic review of English and non-English articles using Embase, PubMed, Web of Science and Google scholar databases. Search terms included Nanofat, fragmented fat, mechanical stromal / stem cell, mechanical SVF, SVF gel. We screened all peer-reviewed articles related with mechanical stromal-cell isolation. Author performed a literature query with the aforementioned key words and databases. A total of 276 publications containing the keywords we searched were reached. In these publications, there are 46 different definitions used to obtain mechanical stromal cells. The term SVF is only suitable for enzymatic methods. A different definition is required for mechanical. The most used term nanofat is also not suitable because the product is not in both "fat" and in "nanoscale". We think that the term total stromal-cells would be the most appropriate definition since both extracellular matrix and all stromal cells are protected in mechanical methods.

Adipose tissue micrograft in a scaffold of plasma-gel combined with platelet-derived growth factors in dermal wrinkle regeneration

Background: The dermal aging process and the formation of deep wrinkles are a biological involution that also involves the regeneration system of cells immersed in the extracellular matrix and the papillary dermis. The progressive loss of niches of adult stem cells (MSCs) is more evident after the first third of life; it increases the phenotypic expression and the characteristics of the tissue senescence process. The purpose of this study was to clinically demonstrate that in viable micrograft there may be an improvement of deep wrinkles and surrounding tissues. Methods: This study involved 11 female patients who underwent the correction of deep dermal wrinkles through a suspension containing 0.8 mL of viable micrografts in a 5 mL plasma gel scaffold, obtained from the centrifugation of a 20 cc venous sample peripheral blood, gelled by heat in a dry steriliser and the buffy coat coming from the same venous sample, in order verify overtime the improvement of the interested anatomical area. Individual signs of wrinkles and the degree of correction obtained for each treatment and each area were objectively evaluated by using a 10-0 visual analog scale (VAS), Modified Vancouver scale and Berardesca's scale. Results: With this technique excellent results were obtained. In fact, wrinkles were improved, as well as surrounding tissues, even after 60 days, as shown by the Berardesca's, VAS and Modified Vancouver scales. Conclusion: This retrospective clinical evaluation allowed us to consider the excellent clinical results obtained with this method for the treatment of deep wrinkles and surrounding tissues, through a suspension of progenitors with MSCs derived from adipose tissue (ADSCa) in a not inflammatory plasma gel scaffold combined with buffy coat.

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.

Use of microfiltered vs only disaggregated mesenchymal stem cells from adipose tissue in regenerative medicine

Background: Clinical use of adult mesenchymal stem cells (MSCa) in medicine and regenerative surgery is constantly evolving. Adipose tissue-derived stem cells (ADSc) are capable of inducing the production of new extracellular matrix (ECM), deposition of new collagen and early revascularisation. Methods: Flow cytometry was performed for 2 mL of cell colonies harvested from adipose tissue (AT). Comparation has been made of at disaggregated only and the same at disaggregated and microfiltered at 50 mm, 100 mm and 200 mm. Signs of inflammation after dermo-epidermal regeneration session through the mesotherapy method were observed and compared. Results: Even after filtration, significant number of ADSc was collected. An increase in the size of the filter did not always translate into an increase in the number of cells that were found in the microfiltrate. In the non-filtered at disaggregated in both cases, highest number of cells was found, as expected, but at the expense of more pronounced inflammation. Sampling with the 16 Gauge needle produces superior results compared to the cannula in all cases. Conclusion: With this method in medicine and regenerative surgery it will be easier to exploit the growth factors, mRNA, MicroRNA, lipids and bioactive peptides emitted in the MSCa signalling micro-vesicles as they are isolated from the inflammatory component.

Intraoperative Strategies for Minimal Manipulation of Autologous Adipose Tissue for Cell- and Tissue-Based Therapies: Concise Review

The stromal vascular fraction (SVF) is a heterogeneous population of stem/stromal cells isolated from perivascular and extracellular matrix (ECM) of adipose tissue complex (ATC). Administration of SVF holds a strong therapeutic potential for regenerative and wound healing medicine applications aimed at functional restoration of tissues damaged by injuries or chronic diseases. SVF is commonly divided into cellular stromal vascular fraction (cSVF) and tissue stromal vascular fraction (tSVF). Cellular SVF is obtained from ATC by collagenase digestion, incubation/isolation, and pelletized by centrifugation. Enzymatic disaggregation may alter the relevant biological characteristics of adipose tissue, while providing release of complex, multiattachment of cell-to-cell and cell-to-matrix, effectively eliminating the bioactive ECM and periadventitial attachments. In many countries, the isolation of cellular elements is considered as a "more than minimal" manipulation, and is most often limited to controlled clinical trials and subject to regulatory review. Several alternative, nonenzymatic methods of adipose tissue processing have been developed to obtain via minimal mechanical manipulation an autologous tSVF product intended for delivery, reducing the procedure duration, lowering production costs, decreasing regulatory burden, and shortening the translation into the clinical setting. Ideally, these procedures might allow for the integration of harvesting and processing of adipose tissue for ease of injection, in a single procedure utilizing a nonexpanded cellular product at the point of care, while permitting intraoperative autologous cellular and tissue-based therapies. Here, we review and discuss the options, advantages, and limitations of the major strategies alternative to enzymatic processing currently developed for minimal manipulation of adipose tissue. Stem Cells Translational Medicine 2019;8:1265&1271.

Adipose-derived cellular and cell-derived regenerative therapies in dermatology and aesthetic rejuvenation

Cellular and cell-derived components of adipose-derived tissue for the purposes of dermatologic and aesthetic rejuvenation applications have become increasingly studied and integrated into clinical practice. These components include micro-fragmented fat (nanofat), the stromal vascular fraction (SVF), adipose-derived mesenchymal stem cells (ASC), and extracellular vesicles (EVs), which have all shown capability to repair, regenerate, and rejuvenate surrounding tissue. Various aesthetic applications including hair growth, scar reduction, skin ischemia-reperfusion recovery, and facial rejuvenation are reviewed. In particular, results from preclinical and clinical studies are discussed, with a focus on clarification of nomenclature.