New adipose tissue formation by human adipose-derived stem cells with hyaluronic acid gel in immunodeficient mice

Bioactive Glasses: Advancing Skin Tissue Repair through Multifunctional Mechanisms and Innovations

As a complex and dynamically regulated process, wound healing is collaboratively carried out by multiple types of cells. However, the precise mechanisms by which these cells contribute to immune regulation are not yet fully understood. Although research on bone regeneration has been quite extensive, the application of bioactive glass (BG) in skin tissue repair remains still relatively underexplored. The review focuses on the principles and the latest progress of using BGs for skin tissue repair, highlighting BGs' special performance requirements, including biological activity, biocompatibility, biodegradability, and antibacterial properties, emphasizing their potential for skin tissue repair. In addition, BGs play a substantial role in regulating various inflammatory cells (neutrophils, macrophages, mast cells, etc.) and tissue repair cells [fibroblasts, vascular endothelial cells, mesenchymal stem cells (MSCs), etc.] involved in wound healing. The review also covers recent developments in composite materials incorporating BGs, demonstrating their ability to promote angiogenesis, inhibit wound biofilms, and improve inflammatory responses in chronic wounds. Furthermore, BGs have shown effectiveness in promoting epithelial regeneration and collagen deposition in burn wounds as well as their applications in scar management and post-tumor resection wound care. Finally, we summarize our views on challenges and directions in the emerging field of BGs for skin tissue regeneration research in the future.

SPLASH: Split-Body Randomized Clinical Trial of Poly- l -Lactic Acid for Adipogenesis and Volumization of the Hip Dell

BACKGROUND

Injectable poly- l -lactic acid (PLLA-SCA) increases extracellular matrix to improve skin quality. The hip dell is an underappreciated element of gluteal aesthetics. Adipose tissue has roles in aesthetics and skin functioning.

OBJECTIVE

To investigate the efficacy of PLLA-SCA treatment to induce adipogenesis and volumize the hip dell.

MATERIALS AND METHODS

This was a double-blinded, split-body trial of 15 women with hip dell volume deficits. Each subject was randomized to have 1 hip dell treated with 150 mg of PLLA-SCA while the contralateral hip dell received the equivalent volume of saline. Subjects received 3 treatments at 1-month intervals and were followed for 9 months. Assessments included physician global aesthetic improvement scale, ultrasonography, and histologic examination.

RESULTS

Blinded investigators rated PLLA-SCA-treated hip dells as improved and much improved. The dermis and adipose layers increased in thickness by 26.1% and 27%. These measures, in addition to collagen and elastic fiber quality, were significantly improved compared with saline-treated hip dells, which did not change from baseline. Subject satisfaction was also significantly greater on the PLLA-SCA-treated side. No subject experienced significant adverse effects.

CONCLUSION

Poly- l -lactic acid is a safe and effective method for durable volumization and aesthetic improvement of the hip dell. PLLA-SCA may promote adipogenesis and elastogenesis.

Poly-D,L-Lactic Acid Fillers Increase Subcutaneous Adipose Tissue Volume by Promoting Adipogenesis in Aged Animal Skin

During aging, subcutaneous white adipose tissue (sWAT) thickness and the adipogenic potential of adipose-derived stem cells (ASCs) decline. Poly-D,L-lactic acid (PDLLA) fillers are commonly used to restore diminished facial volume. Piezo1 increases polarizing macrophages towards the M2 phenotype, which promotes the secretion of fibroblast growth factor 2 (FGF2), thereby increasing ASC survival. This study evaluated whether PDLLA enhances adipogenesis in ASCs by modulating M2 polarization in an in vitro senescence model and in aged animals. Lipopolysaccharide (LPS)-induced senescent macrophages showed decreased Piezo1, which was upregulated by PDLLA. CD163 (an M2 marker) and FGF2 were downregulated in senescent macrophages but were upregulated by PDLLA. We evaluated whether reduced FGF2 secretion from senescent macrophages affects ASCs by applying conditioned media (CM) from macrophage cultures to ASCs. CM from senescent macrophages decreased ERK1/2 and proliferation in ASCs, both of which were restored by CM from PDLLA-stimulated senescent macrophages. Adipogenesis inducers (PPAR-γ and C/EBP-α) were downregulated by CM from senescent macrophages but upregulated by CM from PDLLA-stimulated senescent macrophages in ASCs. Similar patterns were observed in aged animal adipose tissue. PDLLA increased Piezo1 activity, M2 polarization, and FGF2 levels. PDLLA also enhanced ERK1/2, cell proliferation, PPAR-γ, and C/EBP-α expression, leading to increased adipose tissue thickness. In conclusion, our study showed that PDLLA increased adipose tissue thickness by modulating adipogenesis.

Decoding the Implications of Glucagon-like Peptide-1 Receptor Agonists on Accelerated Facial and Skin Aging

Following the advent of glucagon-like peptide-1 receptor agonists (GLP-1RAs), subsequent unintended effects such as accelerated facial aging and altered skin health have been noted. This review delves deeper into the causative underlying mechanisms and provides insights into the intricate relationship between GLP-1RAs, adipose tissue, and premature facial aging, thereby highlighting the need for a nuanced understanding of their effects on facial alterations and skin health. Studies exploring the potential effects of GLP-1RAs on facial alterations and offering insights into the possible underlying mechanisms, causes, and clinical implications were included. The accelerated facial aging and altered skin health observed in GLP-1RA patients appears to be multifactorial, involving loss of dermal and subcutaneous white adipose tissue, and altered proliferation and differentiation of adipose-derived stem cells (ADSCs), and impacts on the production and secretion of hormonal and metabolic factors. These changes compromise the structural integrity and barrier function of the skin and may lead to diminished facial muscle mass, further exacerbating the appearance of aging. The insights presented call for a paradigm shift in the clinical management of facial changes induced by GLP-1RAs, with a focus on treatment strategies aimed at targeting ADSC stimulation. These include autologous fat transfers to reintroduce cells rich in ADSCs for rejuvenation, composite fat grafting combining autologous fat with/without stromal vascular fraction, and the strategic use of soft tissue fillers for volume restoration and biostimulation. This review highlights the potential role of GLP-1RAs in modulating adipose tissue dynamics, thereby contributing to accelerated aging through metabolic, structural, and hormonal pathways.

LEVEL OF EVIDENCE: 5

Injectable fillers: current status, physicochemical properties, function mechanism, and perspectives

With the increasing understanding of the aging process and growing desire for minimally invasive treatments, injectable fillers have great potential for correcting and rejuvenating facial wrinkles/folds and contouring the face. However, considering the increasing availability of multiple soft tissue fillers, it is important to understand their inherent biophysical features and specific mechanism. Thus, in this review, we aim to provide an update on the current injectable filler products and analyze and compare their critical physicochemical properties and function mechanisms for volume-filling. Additionally, future trends and development processes for injectable fillers are also proposed.

Effect of Stromal Vascular Fraction on Sustained Volume Retention of Five Different Hyaluronic Acid Fillers

BACKGROUND

The technology of manufacturing hyaluronic acid (HA) fillers is evolving to increase their safety and durability. This study aimed to compare the volume maintenance effect of stromal vascular fraction (SVF) on different types of HA fillers.

METHODS

In this controlled experiment, HA fillers mixed with SVF were injected into the right upper back and HA fillers alone were injected into the left upper back of each mouse. A total of 35 mice were separated into five groups according to the type of commercially used HA filler: Juvederm Voluma XC, Restylane Lyft, Restylane Skinboosters Vital, Giselle Ligne Signature 2, and Giselle Ligne Universal. Nodule size inspection was performed on post-injection days 0, 3, and 56. Ultrasonography for maximal two-dimensional area of filler nodule measurement and histology were performed on the last day of the inspection.

RESULTS

While most of the groups showed a volume reduction of over 50% on day 56, regardless of SVF administration, significant volume maintenance was observed when Giselle Ligne Signature 2 was injected with SVF. Ultrasonographic measurement of two-dimensional filler nodule size showed no significant difference regarding filler types and SVF injection. When compared with the histological results of other fillers mixed with SVF, Giselle Ligne Signature 2 showed marked increase in cell survival and extracellular matrix components in HA particles.

CONCLUSION

SVF showed different efficacies in terms of volume maintenance and cell survival for various HA filler types. The SVF mixture in selective HA filler injections may improve maintenance in clinical settings.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Olfactory mucosa tissue-derived mesenchymal stem cells lysate ameliorates LPS-induced acute liver injury in mice

Background

Acute liver injury (ALI) induced by sepsis seriously endangers the health of human beings every year. Mesenchymal stem cells (MSCs) lysate containing various regulators had a positive effect on anti-inflammation, hoping to provide a promising strategy in ALI.

Methods

Olfactory mucosa-derived mesenchymal stem cells (OM-MSCs) were extracted and identified. The collected OM-MSCs were prepared after repeated freeze–thaw in phosphate buffer solution (PBS). Then, OM-MSCs lysate was filtered for future experiments. To understand the composes of OM-MSCs clearly, we detected the components of OM-MSCs lysate by western blotting. In vitro, OM-MSCs lysate was applied to evaluate the effects on normal human liver cells (LO-2) under stimulation of LPS. Lipopolysaccharide (LPS) was also injected intraperitoneally to build ALI model in mice. We further assessed the anti-inflammatory capacity of OM-MSCs lysate on ALI in vivo by aminotransferase determination, pathology observation, and immunohistochemical staining. Moreover, the immunoblot technique was performed to recognize the changes in inflammatory factors and related proteins.

Results

In this study, we found that OM-MSCs lysate could protect structure effectively, improve the plasma aminotransferases, diminish inflammation by releasing interleukin-10 (IL-10) and transforming growth factor-beta (TGF-β). A significant decrease in tumor necrosis factor-α (TNF-α) also occurred under the treatment of OM-MSCs lysate. In addition, trophic factors originating from OM-MSCs lysate provided a supportive micro-environment for liver recovery. Especially, up-expression of vascular endothelial growth factor (VEGF) in vivo revealed that OM-MSCs might have a great potential for healing.

Conclusions

Our results demonstrated that OM-MSCs lysate could alleviate LPS-induced ALI via decreasing inflammatory cytokines and promoting recovery.

Experimental study of fat derived pellets promoting wound healing in rats

To observe the effect of fat-derived pellets (FDP) on wound healing in rats, the inguinal fat of rats was obtained, and the FDP were obtained after centrifugation. The cell activity and growth factor secretion of FDP were measured. The wounds in rats were created, and FDP was used to treat the wounds of rats. The phenotype of macrophages and the expression of angiogenic factors expression in wounds were measured. The cell viability in FDP remains in high level after centrifugation and the expression of vascular endothelial growth factor (VEGF) and Basic Fibroblast Growth Factor (bFGF) from FDP was observed in vitro. The FDP significantly promoted the wound healing of rats compared with that in control groups. Moreover, the expression of M2 macrophages and VEGF in FDP group were significantly higher than that in the control group. FDP is a kind of stem cell product, which can be obtained from adipose tissue by physical centrifugation. The cytotherapeutic effect of FDP makes it a promising product for wound healing in clinics.

[Paradigm shift in understanding hyaluronic acid filler effects]

Hyaluronic acid (hyaluron; HA) is an important constituent of the extracellular matrix and has an age-dependent decrease in tissue concentration. While natural HA is rapidly degraded, filler cross-linked HA achieve a half-life of 6-12 months. Such fillers enjoy increasing popularity in esthetic medicine and are versatile tools. Although HA fillers can activate fibroblasts it is of minor importance for long-term results. Fillers are injected into subcutaneous adipose tissue. Their interaction with somatic stem cells and mature adipocytes has gained increasing interest. Cross-linked HA can indeed support proliferation of pre-adipocytes, stimulate their differentiation into mature adipocytes and protect the mature cells from senescence, apoptosis and lipolysis. This view offers a new perspective on the development of future fillers for esthetic medicine.

Tetramethylpyrazine/Ligustrazine Can Improve the Survival Rate of Adipose-Derived Stem Cell Transplantation

BACKGROUND

We aimed to study the effect of tetramethylpyrazine/ligustrazine (TMP) on the survival rate of adipose-derived stem cell (ADSC) transplantation.

METHODS

Human ADSCs were cultured and subcultured. Detection of cell growth was performed using CCK8 kit. A total of 12 BALB/c nude mice including 4 groups (group 1: ADSC-hyaluronic acid [HA] + phosphate-buffered saline [PBS]; group 2: ADSC-HA + TMP injection; group 3: ADSC-HA + TMP soaking; group 4: ADSC-HA + TMP injection + TMP soaking) were used for the animal experiments. Furthermore, hematoxylin-eosin staining and oil red O staining were conducted for the frozen section from the animal tissues. Besides, RNA was extracted from the samples, and reverse transcriptase-polymerase chain reaction experiment was performed. At last, samples were detected using transmission electron microscope.

RESULTS

Tetramethylpyrazine/ligustrazine resulted in significant increase for cell proliferation on the seventh day. It was easier to promote the growth of adipose cell after injection and soaking of TMP. Hematoxylin-eosin staining and oil red O stain showed that injection and soaking of TMP could significantly increase the size of fat. The relative expression of peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, and Alu in group 4 was significantly higher than that in other groups.

CONCLUSIONS

Tetramethylpyrazine/ligustrazine can improve the survival rate of ADSC transplantation. The possible mechanisms of it may be that TMP induces the expression of transcription factor associated with fat formation including peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, and Alu and then promotes the growth of adipose cell.

Comparison of Volume Retention and Biocompatibility of Acellular Dermal Matrix/Hyaluronic Acid Filler to Autologous Fat Grafts in a Mouse Model

BACKGROUND

Although fat grafting has become a widely used technique in aesthetic and reconstructive surgeries, resorption is still a challenge. Micronized acellular dermal matrix (ADM) has been considered as a stable, biocompatible soft tissue coverage material that can be used as a volume filler. Here, we compared the bioacceptance and sustainability of ADM hyaluronic acid (HA) filler with human fat graft in a mouse model.

METHODS

Harvested human fat and ADM/HA filler were injected randomly on the dorsal side of mice. Thirty-two mice were analyzed over a 7-week period with respect to volume, weight and microscopic evaluations with hematoxylin and eosin (H&E), epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) staining.

RESULTS

The volume and weight were maintained at 80% and 83%, respectively, in the ADM/HA filler group and 56.5% and 49.7%, respectively, in the fat-grafted group by the 7th week. There were no significant microscopic differences in inflammatory changes and granulation via H&E staining. At 1 and 2 weeks, EGF and VEGF immunostaining intensity scores were lower in the ADM/HA filler group. At 7 weeks, there were no significant differences in immunostaining intensity scores between the two groups.

CONCLUSIONS

During the 7-week experimental period, the ADM/HA filler showed no foreign body reaction and the proper volume was well maintained. This suggests that the ADM/HA filler can possibly be used in small amounts as an alternative to autologous fat grafts.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authorshttp://www.springer.com/00266.

Hopes and Limits of Adipose-Derived Stem Cells (ADSCs) and Mesenchymal Stem Cells (MSCs) in Wound Healing

Adipose tissue derived stem cells (ADSCs) are mesenchymal stem cells identified within subcutaneous tissue at the base of the hair follicle (dermal papilla cells), in the dermal sheets (dermal sheet cells), in interfollicular dermis, and in the hypodermis tissue. These cells are expected to play a major role in regulating skin regeneration and aging-associated morphologic disgraces and structural deficits. ADSCs are known to proliferate and differentiate into skin cells to repair damaged or dead cells, but also act by an autocrine and paracrine pathway to activate cell regeneration and the healing process. During wound healing, ADSCs have a great ability in migration to be recruited rapidly into wounded sites added to their differentiation towards dermal fibroblasts (DF), endothelial cells, and keratinocytes. Additionally, ADSCs and DFs are the major sources of the extracellular matrix (ECM) proteins involved in maintaining skin structure and function. Their interactions with skin cells are involved in regulating skin homeostasis and during healing. The evidence suggests that their secretomes ensure: (i) The change in macrophages inflammatory phenotype implicated in the inflammatory phase, (ii) the formation of new blood vessels, thus promoting angiogenesis by increasing endothelial cell differentiation and cell migration, and (iii) the formation of granulation tissues, skin cells, and ECM production, whereby proliferation and remodeling phases occur. These characteristics would be beneficial to therapeutic strategies in wound healing and skin aging and have driven more insights in many clinical investigations. Additionally, it was recently presented as the tool key in the new free-cell therapy in regenerative medicine. Nevertheless, ADSCs fulfill the general accepted criteria for cell-based therapies, but still need further investigations into their efficiency, taking into consideration the host-environment and patient-associated factors.

Autologous nanofat transplantation accelerates foot wound healing in diabetic rats

Aim: This study explored the effects of local transplantation of autologous nanofat in the treatment of rats with diabetic foot wounds. Materials & methods: Nanofat was transplanted into the left foot wound of diabetic rats. Phosphate-buffered saline injection in the right served as control. We measured wound size, the extent of epithelization, microvessel density and the expression levels of cytokines at six different time-points postoperation. Results: Compared with the control feet, nanofat-treated feet had significantly smaller wound areas at 7 and 9 days after grafting and showed better re-epithelialization, a greater number of microvessels and higher levels of angiogenic factor expression. Conclusion: This research shows that autologous nanofat transplantation can promote diabetic foot wound healing in rats.

Differential Response of Non-cancerous and Malignant Breast Cancer Cells to Conditioned Medium of Adipose tissue-derived Stromal Cells (ASCs)

Background: The application of adipose tissue-derived stromal cells (ASCs) in regenerative medicine has become a growing trend due to its abundance and differentiation potentials. However, several breast cancer studies indicated that ASCs promote tumor progression, therefore, the use of ASCs for reconstruction after oncological surgery poses potential risks. In this study, we aimed to examine whether cancerous or non-cancerous breast cells will exhibit different responses to ASC-derived CM. Methods: ASCs were isolated from residuals of subcutaneous adipose tissue obtained from patients undergoing surgery. Cancerous MCF-7, MDA-MB231, and MDA-MB468 cell lines and one non-cancerous M10/H184B5F5 cell line were cultured with variant concentrations of ASC-derived conditioned medium (CM) for analysis. Results: ASC-derived CM significantly reduced cell viability by triggering apoptosis in MCF-7, MDA-MB231, and MDA-MB468 cell lines. ATM-Chk2-dependent DNA damage response was activated early in cancer cells when exposed to ASC-derived CM. By contrast, prompted cell proliferation instead of cell death was detected in M10/H184B5F5 cells under the treatment of lower CM concentration. Even when exposed to the highest concentration of CM, only cell cycle arrest accompanied by a weak DNA damage response were detected in M10/H184B5F5 cells, no cell deaths were observed. Conclusions: Overall, this study demonstrated that cancerous and non-cancerous breast cells respond differently to ASC-derived CM. ASC-derived CM triggered significant cell death in breast cancer cell lines, however non-cancerous breast cells exhibited dissimilar response to ASC-derived CM.

Aesthetic dermatology: What's new, what's true?

Aesthetic dermatology (AD) is a rapidly growing subspecialty of dermatology. The acceptance of AD in scientific community and the society is associated with its competence, efficiency, and seriousness. This review highlights some recent developments toward new tools, techniques, and understanding in the field of AD. Analyzing the specific needs of patients and assessing the effect by objective measurements is important for further progress. For long time ignored, white adipose tissue has gained increasing interest in biology and rejuvenation. Characterization of dermal and subcutaneous white adipose tissue has made progress. The interaction of hyaluronic acid and calcium hydroxyl apatite (CaHA) fillers with adipocytes could be responsible for clinical efficacy. New developments of oral collagen treatment and highly diluted CaHA to contour the body outside the face will be discussed. Submental contouring using purified desoxycholic acid is another new development.

Fillers and Facial Fat Pads

Fillers are used for facial sculpturing and anti-ageing treatments with increasing popularity. The optimal outcome of any filler treatment depends upon different factors: exact indication, known limitations, filler product, and filler placement. For volumizing effect and longevity of procedures, however, the interaction of fillers and facial fat pads seems to be crucial. Here, we will review the optimum filler injections for facial applications in relationship to new data and concepts concerning facial fat pads anatomy and physiology. Such a view will us enable to provide optimum results in aesthetic procedures.

Adipose‑derived stem cells and hyaluronic acid based gel compatibility, studied in vitro

Minimally invasive aesthetic and cosmetic procedures have increased in popularity. Injectable dermal fillers provide soft tissue augmentation, improve facial rejuvenation and wrinkles, and correct tissue defects. To investigate the use of adipose‑derived stem cells integrated with a hyaluronic acid based gel as a dermal filler, the present study used cytotoxicity studies, proliferation studies, adipogenic and osteogenic differentiation, apoptosis assays and scanning electron microscopy. Although hyaluronic acid induced low levels of apoptosis in adipose‑derived stem cells, its significantly promoted proliferation of adipose‑derived stem cells. Hyaluronic acid demonstrates little toxicity against adipose‑derived stem cells. Adipose‑derived stem cells were able to differentiate into adipocytes and osteoblasts. Furthermore, scanning electron microscopy revealed that adipose‑derived stem cells maintained intact structures on the surface of hyaluronic acid as well as in it, and demonstrated abundant cell attachments. The present study demonstrated the compatibility of adipose‑derived stem cells and hyaluronic acid based gels in vitro.

Pyrintegrin Induces Soft Tissue Formation by Transplanted or Endogenous Cells

Focal adipose deficiency, such as lipoatrophy, lumpectomy or facial trauma, is a formidable challenge in reconstructive medicine, and yet scarcely investigated in experimental studies. Here, we report that Pyrintegrin (Ptn), a 2,4-disubstituted pyrimidine known to promote embryonic stem cells survival, is robustly adipogenic and induces postnatal adipose tissue formation in vivo of transplanted adipose stem/progenitor cells (ASCs) and recruited endogenous cells. In vitro, Ptn stimulated human adipose tissue derived ASCs to differentiate into lipid-laden adipocytes by upregulating peroxisome proliferator-activated receptor (PPARγ) and CCAAT/enhancer-binding protein-α (C/EBPα), with differentiated cells increasingly secreting adiponectin, leptin, glycerol and total triglycerides. Ptn-primed human ASCs seeded in 3D-bioprinted biomaterial scaffolds yielded newly formed adipose tissue that expressed human PPARγ, when transplanted into the dorsum of athymic mice. Remarkably, Ptn-adsorbed 3D scaffolds implanted in the inguinal fat pad had enhanced adipose tissue formation, suggesting Ptn’s ability to induce in situ adipogenesis of endogenous cells. Ptn promoted adipogenesis by upregulating PPARγ and C/EBPα not only in adipogenesis induction medium, but also in chemically defined medium specifically for osteogenesis, and concurrently attenuated Runx2 and Osx via BMP-mediated SMAD1/5 phosphorylation. These findings suggest Ptn’s novel role as an adipogenesis inducer with a therapeutic potential in soft tissue reconstruction and augmentation.

Injected Implant of Uncultured Stromal Vascular Fraction Loaded Onto a Collagen Gel: In Vivo Study of Adipogenesis and Long-term Outcomes

BACKGROUND

Stromal vascular fraction (SVF) cells were used to increase the efficacy of a newly formed adipose tissue in a collagen gel in vitro. However, the outcome of the seeded cells in the collagen gel in vivo remains unknown. We traced the SVF cells in the host tissue and evaluated the efficacy of SVF for fat tissue engineering.

METHODS

The aggregates implanted in the experimental and control groups were prepared by mixing SVF with the collagen gel and Dulbecco's modified Eagle medium with the collagen gel, respectively. The aggregates were implanted using a subcutaneous injection into the backs of immunodeficient mice. The aggregates were harvested 1, 2, 4, and 6 months after implantation; and 9 mice were euthanized each time. Macroscopic changes in the volume and wet weight of the aggregates were assessed. The formation of adipose tissue was studied using hematoxylin and eosin and Nile red staining. The origin and survival of adipocytes in the aggregates were examined through the immunostaining of leptin antibodies, DNA assay, and tracing of SVF cells by 1,1'-dioctadecyl-3,3,3',3'- tetramethylindocarbocyanine perchlorate labeling.

RESULTS

The formation of adipose tissue was observed in all of the aggregates. Implanted human SVF cells remained in the experimental aggregates harvested after 1, 2, and 4 months but not after 6 months. At 6 months, viable adipocytes in both groups were of murine origin. Furthermore, at 6 months, the mean volume of the aggregate (P < 0.001) and the mean percentage of adipocytes (P < 0.001) were significantly higher in the experimental group than in the control group.

CONCLUSIONS

Implanted SVF cells could not be traced in the aggregates harvested at 6 months but promoted the recruitment of host adipocytes to generate more adipose tissue in the experimental group than in the control group.

Hyaluronan in adipose tissue: Beyond dermal filler and therapeutic carrier

Adipose hyaluronan is increasingly recognized as an active player in adipose tissue fibrosis and metabolic dysfunction. However, this role poses as many challenges as opportunities for therapeutic targeting of adipose tissue dysfunction during nutrient oversupply.

Soft tissue fillers as non-specific modulators of adipogenesis: change of the paradigm?

Dermal filler injection is a cornerstone of facial rejuvenation procedures. Based on available data in animal and human studies, we suppose that the activation and proliferation of adipose-derived stem cells and expansion of mature adipocytes play a crucial role in long-term effects of volumizing, tissue tightening and beautification.

Fillers for the improvement in acne scars

Acne is a common inflammatory disease. Scarring is an unwanted end point of acne. Both atrophic and hypertrophic scar types occur. Soft-tissue augmentation aims to improve atrophic scars. In this review, we will focus on the use of dermal fillers for acne scar improvement. Therefore, various filler types are characterized, and available data on their use in acne scar improvement are analyzed.

In vitro and in vivo biocompatibility, bioavailability and tolerance of an injectable vehicle for adipose-derived stem/stromal cells for plastic surgery indications

Soft tissue reconstruction is a challenge in plastic surgery, when replacing lost materials and correcting contour defects. Many permanent and temporary fillers have been used to restore the volume of these lesions, but often with poor results and even complications. Adipose-derived stem/stromal cells (ASCs) and adipose tissue engineering have been suggested as valuable alternatives. In order to inject these cultured cells, it was essential to find a suitable vehicle. The purpose of this study was to evaluate Cytocare(®), an injectable medical device, composed of hyaluronic acid plus amino acids, vitamins and mineral salts. First, ASC viability and bioavailability in the 3 different available Cytocare(®) formulations using the MTT test were assessed; then an animal experiment, testing the tolerance after intradermal injections of both Cytocare(®) alone and with ASCs was carried out. Our in vitro results demonstrate a high biocompatibility of Cytocare(®) resulting in a better viability of ASCs when cultured in Cytocare(®) compared to culture medium (p < 0.05, Mann and Whitney). Cytocare(®) also permits their bioavailability and proliferation, making it a potential transfer vehicle that can retain the cells before their integration around the recipient site. Finally, our animal experiment shows that the ASC + Cytocare(®) combination is well tolerated. In conclusion, Cytocare(®) can be used as a biocompatible scaffold for cultured ASCs in therapeutic treatments, ensuring ASC bioavailability, as well as evidence of excellent tolerance in nude mice.

Bioengineering Beige Adipose Tissue Therapeutics

Unlocking the therapeutic potential of brown/beige adipose tissue requires technological advancements that enable the controlled expansion of this uniquely thermogenic tissue. Transplantation of brown fat in small animal model systems has confirmed the expectation that brown fat expansion could possibly provide a novel therapeutic to combat obesity and related disorders. Expansion and/or stimulation of uncoupling protein-1 (UCP1)-positive adipose tissues have repeatedly demonstrated physiologically beneficial reductions in circulating glucose and lipids. The recent discovery that brown adipose tissue (BAT)-derived secreted factors positively alter whole body metabolism further expands potential benefits of brown or beige/brite adipose expansion. Unfortunately, there are no sources of transplantable BATs for human therapeutic purposes at this time. Recent developments in bioengineering, including novel hyaluronic acid-based hydrogels, have enabled non-immunogenic, functional tissue allografts that can be used to generate large quantities of UCP1-positive adipose tissue. These sophisticated tissue-engineering systems have provided the methodology to develop metabolically active brown or beige/brite adipose tissue implants with the potential to be used as a metabolic therapy. Unlike the pharmacological browning of white adipose depots, implantation of bioengineered UCP1-positive adipose tissues offers a spatially controlled therapeutic. Moving forward, new insights into the mechanisms by which extracellular cues govern stem-cell differentiation and progenitor cell recruitment may enable cell-free matrix implant approaches, which generate a niche sufficient to recruit white adipose tissue-derived stem cells and support their differentiation into functional beige/brite adipose tissues. This review summarizes clinically relevant discoveries in tissue-engineering and biology leading toward the recent development of biomaterial supported beige adipose tissue implants and their potential for the metabolic therapies.