3D bioprinting of fish skin-based gelatin methacryloyl (GelMA) bio-ink for use as a potential skin substitute.

Gelatin methacryloyl (GelMA), typically derived from mammalian sources, has recently emerged as an ideal bio-ink for three-dimensional (3D) bioprinting. Herein, we developed a fish skin-based GelMA bio-ink for the fabrication of a 3D GelMA skin substitute with a 3D bioprinter. Several concentrations of methacrylic acid anhydride were used to fabricate GelMA, in which their physical-mechanical properties were assessed. This fish skin-based GelMA bio-ink was loaded with human adipose tissue-derived mesenchymal stromal cells (ASCs) and human platelet lysate (HPL) and then printed to obtain 3D ASCs + HPL-loaded GelMA scaffolds. Cell viability test and a preliminary investigation of its effectiveness in promoting wound closure were evaluated in a critical-sized full thickness skin defect in a rat model. The cell viability results showed that the number of ASCs increased significantly within the 3D GelMA hydrogel scaffold, indicating its biocompatibility property. In vivo results demonstrated that ASCs + HPL-loaded GelMA scaffolds could delay wound contraction, markedly enhanced collagen deposition, and promoted the formation of new blood vessels, especially at the wound edge, compared to the untreated group. Therefore, this newly fish skin-based GelMA bio-ink developed in this study has the potential to be utilized for the printing of 3D GelMA skin substitutes.

Anti-inflammatory effects of polydeoxyribonucleotide and adipose tissue-derived mesenchymal stem cells in a canine cell model of osteoarthritis.

IMPORTANCE: A relatively new therapeutic agent for osteoarthritis (OA), polydeoxyribonucleotide (PDRN), shows potential in treating human OA due to its regenerative and anti-inflammatory effects. However, studies on PDRN for canine OA are limited, and no study has investigated their use with mesenchymal stem cells (MSCs) conventionally used for OA treatment. OBJECTIVE: This study aimed to evaluate the potential of PDRN and explore its combined effect with adipose tissue-derived MSCs (AdMSCs) in treating canine OA. METHODS: To study the impact of PDRN, canine chondrocytes, synoviocytes, and AdMSCs were exposed to various PDRN concentrations, and viability was assessed using cell counting kit-8. The OA model was created by treating chondrocytes and synoviocytes with lipopolysaccharide, followed by treatment under three different conditions: PDRN alone, AdMSCs alone, and a combination of PDRN and AdMSCs. Using real-time quantitative polymerase chain reaction, the anti-inflammatory effects and mechanisms were investigated by quantitatively assessing pro-inflammatory cytokines, collagen degradation markers, adenosine A2a receptor (ADORA2A), and nuclear factor-kappa B. RESULTS: PDRN alone and combined with AdMSCs significantly reduced the expression of pro-inflammatory cytokines and collagen degradation markers in an OA model. PDRN promoted AdMSC proliferation and upregulated ADORA2A expression. AdMSCs exhibited comprehensive anti-inflammatory effects through paracrine effects, and both substances reduced inflammatory gene expression through different mechanisms, potentially enhancing therapeutic effects. CONCLUSIONS AND RELEVANCE: The results indicate that PDRN is a safe and effective anti-inflammatory material that can be used independently or as an adjuvant for AdMSCs. Although additional research is necessary, this study is significant because it provides a foundation for future research at the cellular level.

The Adrenal Pheochromocytoma Cell Line PC12 Efficiently Promotes the Regeneration Capability of Adipose Tissue-Derived Mesenchymal Stem Cells in Myogenesis: A Particular Approach to Improving Skeletal Muscle Cell Regeneration.

Background: Researchers are looking for a way to improve the myogenic differentiation of stem cells. Adipose-derived stem cells (ADSCs), known for their multipotency and regenerative capabilities, have been extensively studied for their therapeutic potential. Meanwhile, PC12 cells, derived from rat pheochromocytoma, have been found pivotal in neuroscience research, particularly as a neuronal model system. The current study investigated the effect of the PC12 adrenal pheochromocytoma cell line on the myogenic differentiation of ADSCs. Methods: This experimental study was conducted during 2019-2022 (Ahvaz, Iran). Differentiation of ADSCs was induced by using 3 µg/mL 5-azacytidine for 24 hours. Then, the culture media was changed with Dulbecco's Modified Eagle-High Glucose (DMEM-HG) containing 5% horse serum (HS) and kept for 7 days. Different percentages of differentiated ADSCs and PC12 (100:0, 70:30, 50:50, 30:70) were cocultured for 7 days in DMEM-HG containing 5% HS. PC12 was labeled with cell tracker C7000. The real-time polymerase chain reaction and Western blotting techniques were utilized to assess gene and protein expression. All experiments were repeated three times. Data were analyzed using GraphPad Prism 8.0.2 software with a one-way analysis of variance. P<0.05 was considered statistically significant. Results: PC12 visualization confirmed the accuracy of the co-culture process. The differentiated cells showed an aligned, multinucleated shape. The differentiated ADSCs revealed significantly elevated levels of Myh1, Myh2, and Chrn-α1 gene expression compared with undifferentiated ADSCs (P<0.0001). The ADSCs cocultured with PC12 cells showed significantly higher Myh1, Myh2, and Chrn-α1 gene expression than differentiated ADSCs (P<0.001). ADSCs cocultured with 50% PC12 revealed significantly higher MYH and nAchR protein expression than the differentiated group (P<0.01 and P<0.001). Conclusion: Coculturing PC12 cells and ADSCs improves the efficiency of myogenic differentiation. However, the effectiveness of myogenic differentiation depends on the proportions of administered PC12 cells.

SUN1 inhibits osteogenesis and promotes adipogenesis of human adipose-derived stem cells by regulating α-tubulin and CD36 expression.

Sad and UNC84 domain 1 (SUN1) is a kind of nuclear envelope protein with established involvement in cellular processes, including nuclear motility and meiosis. SUN1 plays an intriguing role in human adipose-derived stem cells (hASCs) differentiation; however, this role remains largely undefined. This study was undertaken to investigate the role of SUN1 in hASCs differentiation, as well as its underlying mechanisms. Employing siRNAs, we selectively downregulated SUN1 and CD36 expression. Microtubules were depolymerized using nocodazole, and PPARγ was activated using rosiglitazone. Western blotting was performed to quantify SUN1, PPARγ, α-tubulin, CD36, OPN, and adiponectin protein expression levels. Alkaline phosphatase and Oil red O staining were used to assess osteogenesis and adipogenesis, respectively. Downregulated SUN1 expression increased osteogenesis and decreased adipogenesis in hASCs, concomitant with upregulated α-tubulin expression and downregulated CD36 expression, alongside reduced nuclear localization of PPARγ. Microtubule depolymerization increased CD36 expression. Rescue experiments indicated that microtubule depolymerization counteracted the downregulated SUN1-induced phenotypic changes. This study demonstrates that SUN1 influences the differentiation of hASCs towards osteogenic and adipogenic lineages, indicating its essential role in cell fate.

Nervonic acid improves fat transplantation by promoting adipogenesis and angiogenesis.

Adipose tissue engraftment has become a promising strategy in the field of regenerative surgery; however, there are notable challenges associated with it, such as resorption of 50­90% of the transplanted fat or cyst formation due to fat necrosis after fat transplantation. Therefore, identifying novel materials or methods to improve the engraftment efficiency is crucial. The present study investigated the effects of nervonic acid (NA), a monounsaturated very long­chain fatty acid, on adipogenesis and fat transplantation, as well as its underlying mechanisms. To assess this, NA was used to treat cells during adipogenesis in vitro, and the expression levels of markers, including PPARγ and CEBPα, and signaling molecules were detected through reverse transcription­quantitative PCR and western blotting. In addition, NA was mixed with fat grafts in in vivo fat transplantation, followed by analysis through Oil Red O staining, hematoxylin & eosin staining and immunohistochemistry. It was demonstrated that NA treatment accelerated adipogenesis through activation of the Akt/mTOR pathway and inhibition of Wnt signaling. NA treatment enriched the expression of Akt/mTOR signaling­related genes, and increased the expression of genes involved in angiogenesis and fat differentiation in human mesenchymal stem cells (MSCs). Additionally, NA effectively improved the outcome of adipose tissue engraftment in mice. Treatment of grafts with NA at transplantation reduced the resorption of transplanted fat and increased the proportion of perilipin­1+ adipocytes with a lower portion of vacuoles in mice. Moreover, the NA­treated group exhibited a reduced pro­inflammatory response and had more CD31+ vessel structures, which were relatively evenly distributed among viable adipocytes, facilitating successful engraftment. In conclusion, the present study demonstrated that NA may not only stimulate adipogenesis by regulating signaling pathways in human MSCs, but could improve the outcome of fat transplantation by reducing inflammation and stimulating angiogenesis. It was thus hypothesized that NA could serve as an adjuvant strategy to enhance fat engraftment in regenerative surgery.

Depot-specific mRNA expression programs in human adipocytes suggest physiological specialization via distinct developmental programs.

Adipose tissue is distributed in diverse locations throughout the human body. Not much is known about the extent to which anatomically distinct adipose depots are functionally distinct, specialized organs, nor whether depot-specific characteristics result from intrinsic developmental programs, as opposed to reversible physiological responses to differences in tissue microenvironment. We used DNA microarrays to compare mRNA expression patterns of isolated human adipocytes and cultured adipose stem cells, before and after ex vivo adipocyte differentiation, from seven anatomically diverse adipose tissue depots. Adipocytes from different depots display distinct gene expression programs, which are most closely shared with anatomically related depots. mRNAs whose expression differs between anatomically diverse groups of depots (e.g., subcutaneous vs. internal) suggest important functional specializations. These depot-specific differences in gene expression were recapitulated when adipocyte progenitor cells from each site were differentiated ex vivo, suggesting that progenitor cells from specific anatomic sites are deterministically programmed to differentiate into depot-specific adipocytes. Many developmental transcription factors show striking depot-specific patterns of expression, suggesting that adipocytes in each anatomic depot are programmed during early development in concert with anatomically related tissues and organs. Our results support the hypothesis that adipocytes from different depots are functionally distinct and that their depot-specific specialization reflects distinct developmental programs.

Altered Cytokine Secretory Fingerprint of the Adipocytes Derived from Stem Cells of Morbidly Obese Patients-A Preliminary Study.

Context: Adipose-derived mesenchymal stem cells (ADMSCs) are progenitor cells that shape the tissue's biological properties. Objective: To examine the adipocytes differentiated from the ADMSCs of lean and obese individuals with/without a metabolic syndrome (MetSx) cytokine secretory profile, as to date, little is known on this topic. Methods: Interleukin, chemokine and growth factor levels in the culture medium were determined using the Human Cytokine kit. Results: We observed a characteristic secretory fingerprint displayed by the cells from the MetSx group and identified a set of putative markers (IL-1ß, IL-6, IL-7, IL-10, IL-12, IL-13, VEGF, FGF, GM-CSF, TNF-α, IFN-γ) of the condition. Surprisingly, the concentrations of most of the molecules (except for IL-6, IFN-γ, IP-10, VEGF) decreased when compared with the cells from the lean group. We postulate that the difference stemmed from the fact that in vivo cytokines were mostly secreted by the activated monocytes/macrophages and not adipocytes per se. This may also suggest that the aforementioned upregulated cytokines (IL-6, IFN-γ, IP-10, VEGF) might have been the ones that attracted monocytes and triggered the vicious cycle of tissue inflammation. Conclusions: Our study indicated that the adipocytes newly derived from the ADMSCs of obese patients with metabolic syndrome displayed a secretory fingerprint that may be characteristic to the early stages of the condition.

Photobiomodulation effects on neuronal transdifferentiation of immortalized adipose-derived mesenchymal stem cells.

Adipose-derived mesenchymal stem cells (ADMSCs) possess the ability to transform into various cell types, including neurons. It has been proposed that the optimization of this transformation can be achieved by using photobiomodulation (PBM). The objective of this laboratory-based investigation was to induce the transformation of immortalized ADMSCs (iADMSCs) into neurons with chemical triggers and then evaluate the supportive effects of PBM at two different wavelengths, 525 nm and 825 nm, each administered at a dose of 5 J/cm2, as well as the combined application of these wavelengths. The results revealed that the treated cells retained their stem cell characteristics, although the cells exposed to the green laser exhibited a reduction in the CD44 marker. Furthermore, early, and late neuronal markers were identified using flow cytometry analysis. The biochemical analysis included the assessment of cell morphology, viability, cell proliferation, potential cytotoxicity, and the generation of reactive oxygen species (ROS). The findings of this study indicate that PBM does not harm the differentiation process and may even enhance it, but it necessitates a longer incubation period in the induction medium. These research findings contribute to the validation of stem cell technology for potential applications in in vivo, pre-clinical, and clinical research environments.

3D spheroids versus 2D-cultured human adipose stem cells to generate smooth muscle cells in an internal anal sphincter-targeting cryoinjured mouse model.

BACKGROUND: The efficacy of cell implantation via 3D-spheroids to treat basal tone in fecal incontinence remains unclear. To address this, in this study, we aimed to identify cell differentiation and assess the development of a contractile phenotype corresponding to smooth muscle cells (SMCs) following implantation of 3D-spheroid and 2D-cultured human adipose stem cells (hASCs) in an in vivo internal anal sphincter (IAS)-targeted mouse model. METHODS: We developed an IAS-targeted in vivo model via rapid freezing (at - 196 °C) of the dorsal layers of the region of interest (ROI) of the IAS ring posterior quarter, between the submucosal and muscular layers, following submucosal dissection (n = 60 rats). After implantation of tetramethylindocarbocyanine perchlorate (Dil)-stained 3D and 2D-cells into randomly allocated cryoinjured rats, the entire sphincter ring or only the cryoinjured ROI was harvested. Expression of SMC markers, RhoA/ROCKII and its downstream molecules, and fibrosis markers was analyzed. Dil, α-smooth muscle actin (α-SMA), and RhoA signals were used for cell tracking. RESULTS: In vitro, 3D-spheroids exhibited higher levels of SMC markers and RhoA/ROCKII-downstream molecules than 2D-hASCs. The IAS-targeted cryoinjured model exhibited substantial loss of SMC layers of the squamous epithelium lining of the anal canal, as well as reduced expression of SMC markers and RhoA-related downstream molecules. In vivo, 3D-spheroid implantation induced SMC markers and contractile molecules weakly at 1 week. At 2 weeks, the mRNA expression of aSma, Sm22a, Smoothelin, RhoA, Mypt1, Mlc20, Cpi17, and Pp1cd increased, whereas that of fibrosis markers reduced significantly in the 3D-spheroid implanted group compared to those in the sham, non-implanted, and 2D-hASC implanted groups. Protein levels of RhoA, p-MYPT1, and p-MLC20 were higher in the 3D-spheroid-implanted group than in the other groups. At 2 weeks, in the implanted groups, the cryoinjured tissues (which exhibited Dil, α-SMA, and RhoA signals) were restored, while they remained defective in the sham and non-implanted groups. CONCLUSIONS: These findings demonstrate that, compared to 2D-cultured hASCs, 3D-spheroids more effectively induce a contractile phenotype that is initially weak but subsequently improves, inducing expression of RhoA/ROCKII-downstream molecules and SMC differentiation associated with IAS basal tone.

Adipose derived or bone-marrow derived mesenchymal stem cell treatment for hyposalivation: protocol for a systematic review and network meta-analysis.

BACKGROUND: Salivary hypofunction leads to debilitating oral symptoms and has major complications for overall quality of life. Two of the most frequent causes of xerostomia are radiotherapy in the head and neck and Sjögren's syndrome. Only symptomatic treatment is available today. An increasing number of both preclinical and clinical studies have suggested that mesenchymal stem cell (MSC) transplantation treatment can increase the salivary flow rate and ameliorate symptoms of xerostomia. However, both adipose-derived and bone marrow-derived MSCs are used, although they differ in important ways. The primary objective of this study is an indirect comparison of the change in the unstimulated salivary flow rate after intervention between patients treated with adipose-derived or bone marrow-derived MSCs. METHODS: This systematic review and network meta-analysis will search for eligible studies in the MEDLINE, EMBASE, and Cochrane CENTRAL register of Controlled Trials. Eligible studies are as follows: clinical studies including human patients with salivary hypofunction due to either radiotherapy or Sjogren's syndrome who were subsequently treated with either adipose-derived MSCs or bone marrow-derived MSCs. Studies with no control group will be excluded. The search phrase has been peer-reviewed following the PRESS guidelines. The primary outcome is the change in the unstimulated salivary flow rate after treatment with either adipose-derived or bone marrow-derived MSCs. Secondary outcomes are as follows: change in patient reported outcomes, methods of intervention administration, number of injected MSCs, and safety. Data from included studies will be pooled and compared with a fixed-effects or random effects model dependent on signs of heterogeneity, presented with a forest plot, and indirectly compared with a meta-regression in a network meta-analysis. Risk of bias will be assessed with the tools ROBINS-I or RoB-2 depending on type of study. DISCUSSION: Both adipose-derived and bone marrow-derived MSCs are used today for experimental treatment of salivary hypofunction in humans as no direct or indirect comparisons have been made. Therefore, an evaluation of the effect of adipose-derived vs bone marrow-derived MSC treatment is needed to support future decision-making on the type of MSC used in a clinical trial. SYSTEMATIC REVIEW REGISTRATION: PROSPERO ID CRD42024527183.

Research progress and application prospect of adipose-derived stem cell secretome in diabetes foot ulcers healing.

Diabetic foot ulcers (DFUs) are chronic wounds and one of the most common complications of diabetes, imposing significant physical and mental burdens on patients due to their poor prognosis and treatment efficacy. Adipose-derived stem cells (ADSCs) have been proven to promote wound healing, with studies increasingly attributing these beneficial effects to their paracrine actions. Consequently, research on ADSC secretome as a novel and promising alternative for DFU treatment has been extensively conducted. This article provides a comprehensive review of the mechanisms underlying refractory DFU wounds, the secretome of ADSCs, and its role in promoting wound healing in diabetes foot ulcers. And the review aims to provide reliable evidence for the clinical application of ADSC secretome in the treatment of refractory DFU wounds.

Dipeptidyl peptidase-4 marks distinct subtypes of human adipose stromal/stem cells with different hepatocyte differentiation and immunoregulatory properties.

BACKGROUND: Human adipose-derived stromal/stem cells (hASCs) play important roles in regenerative medicine and numerous inflammatory diseases. However, their cellular heterogeneity limits the effectiveness of treatment. Understanding the distinct subtypes of hASCs and their phenotypic implications will enable the selection of appropriate subpopulations for targeted approaches in regenerative medicine or inflammatory diseases. METHODS: hASC subtypes expressing dipeptidyl peptidase-4 (DPP4) were identified via fluorescence-activated cell sorting (FACS) analysis. DPP4 expression was knocked down in DPP4+ hASCs via DPP4 siRNA. The capacity for proliferation, hepatocyte differentiation, inflammatory factor secretion and T-cell functionality regulation of hASCs from DPP4-, DPP4+, and control siRNA-treated DPP4+ hASCs and DPP4 siRNA-treated DPP4+ hASCs were assessed. RESULTS: DPP4+ hASCs and control siRNA-treated DPP4+ hASCs presented a lower proliferative capacity but greater hepatocyte differentiation capacity than DPP4- hASCs and DPP4 siRNA-treated DPP4+ hASCs. Both DPP4+ hASCs and DPP4- hASCs secreted high levels of vascular endothelial growth factor-A (VEGF-A), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6 (IL-6), whereas the levels of other factors, including matrix metalloproteinase (MMP)-1, eotaxin-3, fractalkine (FKN, CX3CL1), growth-related oncogene-alpha (GRO-alpha, CXCL1), monokine induced by interferon-gamma (MIG), macrophage inflammatory protein (MIP)-1beta, and macrophage colony-stimulating factor (M-CSF), were significantly greater in the supernatants of DPP4+ hASCs than in those of DPP4- hASCs. Exposure to hASC subtypes and their conditioned media triggered changes in the secreted cytokine profiles of T cells from healthy donors. The percentage of functional T cells that secreted factors such as MIP-1beta and IL-8 increased when these cells were cocultured with DPP4+ hASCs. The percentage of polyfunctional CD8+ T cells that secreted multiple factors, such as IL-17A, tumour necrosis factor alpha (TNF-α) and TNF-ß, decreased when these cells were cocultured with supernatants derived from DPP4+ hASCs. CONCLUSIONS: DPP4 may regulate proliferation, hepatocyte differentiation, inflammatory cytokine secretion and T-cell functionality of hASCs. These data provide a key foundation for understanding the important role of hASC subpopulations in the regulation of T cells, which may be helpful for future immune activation studies and allow them to be customized for clinical application.

The role of adipose tissue-derived stromal cells, macrophages and bioscaffolds in cutaneous wound repair.

Skin healing is a complex and dynamic physiological process that follows mechanical alteration of the skin barrier. Under normal conditions, this complex process can be divided into at least three continuous and overlapping phases: an inflammatory reaction, a proliferative phase that leads to tissue reconstruction and a phase of tissue remodeling. Macrophages critically contribute to the physiological cascade for tissue repair. In fact, as the inflammatory phase progresses, macrophage gene expression gradually shifts from pro-inflammatory M1-like to pro-resolutive M2-like characteristics, which is critical for entry into the repair phase. A dysregulation in this macrophage' shift phenotype leads to the persistence of the inflammatory phase. Mesenchymal stromal cells and specifically the MSC-derived from adipose tissue (ADSCs) are more and more use to treat inflammatory diseases and several studies have demonstrated that ADSCs promote the wound healing thanks to their neoangiogenic, immunomodulant and regenerative properties. In several studies, ADSCs and macrophages have been injected directly into the wound bed, but the delivery of exogenous cells directly to the wound raise the problem of cell engraftment and preservation of pro-resolutive phenotype and viability of the cells. Complementary approaches have therefore been explored, such as the use of biomaterials enriched with therapeutic cell to improve cell survival and function. This review will present a background of the current scaffold models, using adipose derived stromal-cells and macrophage as therapeutic cells for wound healing, through a discussion on the potential impact for future applications in skin regeneration. According to the PRISMA statement, we resumed data from investigations reporting the use ADSCs and bioscaffolds and data from macrophages behavior with functional biomaterials in wound healing models. In the era of tissue engineering, functional biomaterials, that can maintain cell delivery and cellular viability, have had a profound impact on the development of dressings for the treatment of chronic wounds. Promising results have been showed in pre-clinical reports using ADSCs- and macrophages-based scaffolds to accelerate and to improve the quality of the cutaneous healing.

Adipose-derived stem cell transplantation enhances spinal cord regeneration by upregulating PGRN expression.

This study aims to investigate the effect of adipose-derived stem cells (ADSCs) transplantation on progranulin (PGRN) expression and functional recovery in rats with spinal cord injury (SCI). ADSCs were isolated from the inguinal adipose tissue of rats. A SCI model was created, and ADSCs were injected into the injured area. Various techniques were used to assess the effects of ADSCs transplantation, including hematoxylin-eosin staining, Masson staining, immunofluorescence staining, electron microscopy, MRI, and motor function assessment. The potential mechanisms of ADSC transplantation were investigated using gene expression analysis and protein analysis. Finally, the safety of this therapy was evaluated through hematoxylin-eosin staining and indicators of liver and kidney damage in serum. PGRN expression increased in the injured spinal cord, and ADSCs transplantation further enhanced PGRN levels. The group that received ADSCs transplantation showed reduced inflammation, decreased scar formation, increased nerve regeneration, and faster recovery of bladder function. Importantly, motor function significantly improved in the ADSC transplantation group. ADSCs transplantation enhances functional regeneration in SCI by upregulating PGRN expression, reducing inflammation and scar formation, and promoting nerve regeneration and myelin repair. These findings suggest that ADSC transplantation is a potential therapy for SCI.

Optimizing adipose-derived stromal vascular fraction storage: Temperature and time impact on cell viability in regenerative medicine.

BACKGROUND: The adipose-derived stromal vascular fraction (SVF) plays a crucial role in regenerative medicine owing to its regenerative and immunomodulatory properties. However, the effective utilization of SVF in therapeutic applications requires careful consideration of storage conditions to maintain cell viability. METHODS: We conducted a research on 43 patients of different ages and sexes who were older than 18 years. This study explored the impact of different temperatures (-80, -20, and 4 °C) on SVF storage in platelet-poor plasma for 1 and 6 months. SVF extracted using a semi-UNISTATION™ system was subjected to rigorous analysis of cell count and viability using a LUNA-STEM™ Dual Fluorescence Cell Counter. RESULTS: The results indicated a significant correlation between the storage conditions and SVF viability. Notably, storing SVF at 4 °C demonstrated the highest cell viability and count, while -80 °C storage exhibited the least favorable outcomes. This study emphasizes the importance of minimizing storage time to preserve SVF viability, as evidenced by a decline in both cell count and viability over a 6-month period. Comparisons with the existing literature underscore the need for precise protocols for SVF storage, with considerations for temperature and cryoprotective agents. These findings provide valuable insights for developing optimal SVF storage protocols to enhance therapeutic outcomes and reduce the need for repeated adipose tissue harvesting. Despite the limitations of the study, such as the use of a cell counter instead of flow cytometry, the results establish the foundation for further research on refining SVF storage methods. CONCLUSION: The ideal storage temperature is from 4 °C, while the length of storage time inversely affects the viability of SVF; the longer the storage time, the lower the number and the viability of SVF cells, regardless of the temperature at which they are preserved.

Exosomal miR­194 from adipose­derived stem cells impedes hypertrophic scar formation through targeting TGF­ß1.

Hypertrophic scars, which result from aberrant fibrosis and disorganized collagen synthesis by skin fibroblasts, emerge due to disrupted wound healing processes. These scars present significant psychosocial and functional challenges to affected individuals. The current treatment limitations largely arise from an incomplete understanding of the underlying mechanisms of hypertrophic scar development. Recent studies, however, have shed light on the potential of exosomal non­coding RNAs interventions to mitigate hypertrophic scar proliferation. The present study assessed the impact of exosomes derived from adipose­derived stem cells (ADSCs­Exos) on hypertrophic scar formation using a rabbit ear model. It employed hematoxylin and eosin staining, Masson's trichrome staining and immunohistochemical staining techniques to track scar progression. The comprehensive analysis of the present study encompassed the differential expression of non­coding RNAs, enrichment analyses of functional pathways, protein­protein interaction studies and micro (mi)RNA­mRNA interaction investigations. The results revealed a marked alteration in the expression levels of long non­coding RNAs and miRNAs following ADSCs­Exos treatment, with little changes observed in circular RNAs. Notably, miRNA (miR)­194 emerged as a critical regulator within the signaling pathways that govern hypertrophic scar formation. Dual­luciferase assays indicated a significant reduction in the promoter activity of TGF­ß1 following miR­194 overexpression. Reverse transcription­quantitative PCR and immunoblotting assays further validated the decrease in TGF­ß1 expression in the treated samples. In addition, the treatment resulted in diminished levels of inflammatory markers IL­1ß, TNF­α and IL­10. In vivo evidence strongly supported the role of miR­194 in attenuating hypertrophic scar formation through the suppression of TGF­ß1. The present study endorsed the strategic use of ADSCs­Exos, particularly through miR­194 modulation, as an effective strategy for reducing scar formation and lowering pro­inflammatory and fibrotic indicators such as TGF­ß1. Therefore, the present study advocated the targeted application of ADSCs­Exos, with an emphasis on miR­194 modulation, as a promising approach to managing proliferative scarring.

Bone Tissue Engineering with Adipose-Derived Stem Cells in Polycaprolactone/Graphene Oxide/Dexamethasone 3D-Printed Scaffolds.

We fabricated three-dimensional (3D)-printed polycaprolactone (PCL) and PCL/graphene oxide (GO) (PGO) scaffolds for bone tissue engineering. An anti-inflammatory and pro-osteogenesis drug dexamethasone (DEX) was adsorbed onto GO and a 3D-printed PGO/DEX (PGOD) scaffold successfully improved drug delivery with a sustained release of DEX from the scaffold up to 1 month. The physicochemical properties of the PCL, PGO, and PGOD scaffolds were characterized by various analytical techniques. The biological response of these scaffolds was studied for adherence, proliferation, and osteogenic differentiation of seeded rabbit adipose-derived stem cells (ASCs) from DNA assays, alkaline phosphatase (ALP) production, calcium quantification, osteogenic gene expression, and immunofluorescence staining of osteogenic marker proteins. The PGOD scaffold was demonstrated to be the best scaffold for maintaining cell viability, cell proliferation, and osteogenic differentiation of ASCs in vitro. In vivo biocompatibility of PGOD was confirmed from subcutaneous implantation in nude mice where ASC-seeded PGOD can form ectopic bones, demonstrated by microcomputed tomography (micro-CT) analysis and immunofluorescence staining. Furthermore, implantation of PGOD/ASCs constructs into critical-sized cranial bone defects in rabbits form tissue-engineered bones at the defect site, observed using micro-CT and histological analysis.

NORAD accelerates skin wound healing through extracellular vesicle transfer from hypoxic adipose derived stem cells: miR-524-5p pathway and Pumilio protein mechanism.

Skin wound healing is a multifaceted biological process that encompasses a variety of cell types and intricate signaling pathways. Recent research has uncovered that exosomes derived from adipose stem cells, commonly referred to as ADSC exosomes, play a crucial role in facilitating the healing process. Moreover, it has been demonstrated that an anoxic, or low-oxygen, environment significantly enhances the effectiveness of these exosomes in promoting skin repair. The primary objective of this study was to investigate the underlying mechanisms through which ADSC exosomes contribute to Skin wound healing, particularly by regulating the long non-coding RNA known as NORAD under hypoxic conditions. A significant focus of our research was to examine the interplay between the microRNA miR-524-5p and the Pumilio protein, as we aimed to understand how these molecular interactions might influence the overall healing process. In this study, ADSC exosomes were extracted by simulating hypoxia in vitro and their effects on the proliferation and migration of skin fibroblasts (FB) were evaluated. The expression levels of NORAD, miR-524-5p and Pumilio were analyzed by fluorescence quantitative PCR. Pumilio protein was silenced by siRNA technique to evaluate its role in ADSC exosome-mediated wound healing. The experimental results showed that under hypoxia conditions, NORAD levels in ADSC exosomes increased significantly and could effectively regulate the expression of miR-524-5p. After Pumilio protein silencing, the proliferation and migration ability of fibroblasts were significantly reduced, indicating that Pumilio protein played a role in the process of wound healing. By inhibiting miR-524-5p, the expression of Pumilio protein was restored, further confirming its regulatory mechanism.

An antimicrobial microneedle patch promotes functional healing of infected wounds through controlled release of adipose tissue-derived apoptotic vesicles.

The high incidence and mortality rates associated with acute and chronic wound infections impose a significant burden on global healthcare systems. In terms of the management of wound infection, the reconstruction and regeneration of skin appendages are essential for the recovery of mechanical strength and physiological function in the regenerated skin tissue. Novel therapeutic approaches are a requisite for enhancing the healing of infected wounds and promoting the regeneration of skin appendages. Herein, a novel antimicrobial microneedle patch has been fabricated for the transdermal controlled delivery of adipose tissue-derived apoptotic vesicles (ApoEVs-AT@MNP) for the treatment of infected wounds, which is expected to achieve high-quality scarless healing of the wound skin while inhibiting the bacteria in the infected wound. The microneedle patch (MNP) system possesses adequate mechanical strength to penetrate the skin, allowing the tips to remain inside tissue for continuous active release of biomolecules, and subsequently degrades safely within the host body. In vivo transplantation demonstrates that ApoEVs-AT@MNP not only inhibits bacterial proliferation in infected wounds but also significantly promotes effective and rapid scarless wound healing. Particularly noteworthy is the ability of ApoEVs-AT@MNP to promote the rapid formation of mature, evenly arranged hair follicles in infected wounds, observed as early as 8 days following implantation, which is essential for the restoration of skin function. This rapid development of skin appendages has not been reported this early in previous studies. Therefore, ApoEVs-AT@MNP has emerged as an excellent, painless, non-invasive, and highly promising treatment for infected wounds.

Non-animal derived recombinant collagen-based biomaterials as a promising strategy towards adipose tissue engineering.

Adipose tissue engineering (ATE) has been gaining increasing interest over the past decades, offering promise for new and innovative breast reconstructive strategies. Animal-derived gelatin-methacryloyl (Gel-MA) has already been applied in a plethora of TE strategies. However, due to clinical concerns, related to the potential occurrence of immunoglobulin E-mediated immune responses and pathogen transmission, a shift towards defined, reproducible recombinant proteins has occurred. In the present study, a recombinant protein based on human collagen type I, enriched with arginine-glycine-aspartic acid was functionalized with photo-crosslinkable methacryloyl moieties (RCPhC1-MA), processed into 3D scaffolds and compared with frequently applied Gel-MA from animal origin using an indirect printing method applying poly-lactic acid as sacrificial mould. For both materials, similar gel fractions (>65%) and biodegradation times were obtained. In addition, a significantly lower mass swelling ratio (17.6 ± 1.5 versus 24.3 ± 1.4) and mechanical strength (Young's modulus: 1.1 ± 0.2 kPa versus 1.9 ± 0.3 kPa) were observed for RCPhC1-MA compared to Gel-MA scaffolds.In vitroseeding assays showed similar cell viabilities (>80%) and a higher initial cell attachment for the RCPhC1-MA scaffolds. Moreover, the seeded adipose-derived stem cells could be differentiated into the adipogenic lineage for both Gel-MA and RCPhC1-MA scaffolds, showing a trend towards superior differentiation for the RCPhC1-MA scaffolds based on the triglyceride and Bodipy assay. RCPhC1-MA scaffolds could result in a transition towards the exploitation of non-animal-derived biomaterials for ATE, omitting any regulatory concerns related to the use of animal derived products.