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Mesenchymal stem cell (MSC)-based therapies are promising for regenerative medicine because of their trophic, immunomodulatory, and pro-regenerative properties. Human adipose-derived stromal cells (hASCs) are an accessible and clinically relevant MSC source. However, clinical translation is limited by the lack of post-implantation controllability. We therefore aimed to establish a pharmacologically inducible safety switch for engineered hASC-based products and validate its function in 2D culture and 3D spheroid systems for nerve tissue engineering applications

Wild-type hASCs and engineered hASC lines expressing fluorescent reporters with or without the HSV1-sr39 thymidine kinase suicide gene were evaluated in 2D and 3D culture. Spheroids were generated under standardized conditions and exposed to increasing concentrations of ganciclovir (GCV) or penciclovir (PCV). Viability was assessed using ATP-based luminescence assays. A fibrin hydrogel embedding workflow and spheroid characterization were initiated to evaluate encapsulated drug response and preservation of key MSC features.

Engineered hASC spheroids were reproducibly generated in 3D culture, enabling quantitative dose-response analysis. Preliminary data showed a clear dose-dependent loss of viability in suicide gene-expressing hASCs following GCV or PCV exposure in both 2D and 3D systems. In contrast, wild-type and reporter-only control cells showed minimal nonspecific response. At higher GCV and PCV concentrations, more than 95% cell death was observed in suicide gene-expressing conditions, confirming functionality of the safety switch in 3D spheroids.

These findings provide proof of concept for a safety switch strategy in MSC-based therapies. The system was effective not only in monolayer culture but also in 3D hASC spheroids, supporting the feasibility of integrating a controllable suicide-gene module into regenerative MSC platforms to improve translational safety. Ongoing work will refine dose-response characterization and determine whether engineered hASC spheroids retain regenerative properties alongside controllability.

Repair and regeneration of traumatic nerve injury is clinically challenging due to the lack of effective treatment strategies . Biomaterial-based scaffolds assist nerve regeneration by providing structural support. Schwann cells (SCs) play an essential role in nerve tissue regeneration by secreting variety of neurotrophic factors and by self-aligning into axonal guidance structures. However, biomaterials for effective delivery of SCs are scarce in the field, thus limiting their clinical applications. Within this context, this project investigates laminin functionalized biomaterial as a potential carrier scaffold for engineering of aligned Schwann cell bundles. Resulting 3D-bioprinted tissue constructs, with neurotrophic and topographical guidance properties, holds great promise for neural tissue engineering applications.

Extrusion based 3D bioprinting was used to print uniaxial filaments of GelMA and GelMA-Laminin with 10mm in length, 0.5 mm in thickness, and 5 × 103 rat Schwann cells per filament. Cell viability, alignment of the printed cells was assessed from Calcein AM, Ethidium bromide and Phalloidin stainings at different time points. Further, DRG explant was seeded on the hydrogel surface and cultured for 6 days for assessing the axonal outgrowth and elongation kinetics.

As shown in Fig 1a, Phalloidin staining confirms that both gels support proper cell adhesion, although GelMA-Laminin had a significantly higher spreading area compared to GelMA. In consistency with viability, cells also displayed increased elongation with longer cytoskeletal structure resulting in aligned cell bundles (Fig 1b). DRG cultured on both hydrogel had a time dependent neurite outgrowth. Average neurite length was significantly higher in the GelMA/Laminin group compared to GelMA. GelMA/Laminin also exhibited more extensive, organized and directed growth.

These results confirm the biocompatibility of the selected hydrogel scaffolds for bio-printing of Schwann cells and for subsequent alignment of Schwann cell bundles. Enhanced Schwann cell spreading on GelMA-Laminin is likely due to the presence of laminin, a key extracellular matrix protein that promotes cell adhesion through integrin-mediated interactions, also explaining the higher neutrite extension for GelMA-Laminin. Thus, the lamini-functionlized scaffold holds great promise for nerve repair.

Repair and regeneration of traumatic nerve injury is clinically challenging due to the lack of effective treatment strategies. Biomaterial-based artificial nerve guidance conduits (NGCs) have emerged as a promising strategy. Despite the innovations, currently available NGCs lack the necessary structural guidance and biological support as many existing NGCs rely on hollow tubes to bridge the gap, resulting in poor clinical outcomes. Thus, the project aims to develop NGCs, equipped with micro-engineered guidance features and Schwann cells, as the next generation regenerative therapeutics.

A novel strategy based on filamented light (FLight) biofabrication creates unidimensional network of microfilaments employing optical modulation instability of the light beams inside a photoresin. A collagen/silk fibroin photoresin was used to create filamented NGCs of 10mm in length and 2-3mm in diameter of two conditions, with and without macrochannels of 150µm. 1 × 10⁴ rat Schwann cells were seeded per conduit to access biological compatibility in vitro. Cell infiltration and Schwann cell alignment within the NGC through cytoskeletal organization were studied.

Cell infiltration and viability in collagen/silk fibroin conduits showed high cell viability with a live cell area fraction at ~90% in conduits with channels. Compared to conduits without channels, cell infiltration was prominent with throughout the NGC scaffold. The conduits without channels showed limited infiltration into the bulk across time. By day 5, the cells were organized along the direction of microfilament and by day 7, strong and continuous live cell signals throughout the conduit within microchannels and macrochannels are observed with continuous and longitudinal cytoskeletal organization.

Although both conditions support cell viability, the biomimetic microarchitectures enhance cell infiltration, migration and spatial distribution. Well defined channels provide the microstructural fidelity required for effective cell distribution. Contact guidance is supported by the anisotropic geometry created by the filaments, aiding actin fiber alignment and promoting elongated cell morphology. These findings support the proof of concept that filamented microarchitectures provide favorable conditions for guided cell migration and are potentially suitable for nerve repair applications.

Autologous breast reconstruction frequently uses fat grafting to optimize contour and volume; however, long-term graft survival remains variable due to early ischemia and inflammation-mediated adipocyte loss. Mesenchymal stem cell-derived exosomes (MSC-Exos), particularly adipose-derived MSC exosomes (ADSC-Exos), have emerged as cell-free extracellular vesicles capable of modulating angiogenesis and immune balance within the graft microenvironment without the risks associated with live cell transplantation. This study synthesizes recent translational evidence to evaluate the potential role of MSC-Exos as adjuncts in reconstructive breast surgery.

A structured literature synthesis (2018–2025) was conducted using searches in PubMed and EMBASE, focusing on adipose-derived MSC-Exos in fat grafting and soft tissue regeneration models. Priority was given to translational xenograft studies utilizing human adipose tissue and reporting quantitative outcomes including volume retention, vascular density (CD31), and macrophage phenotype distribution. Mechanistic context was derived from peer-reviewed exosome literature describing pro-angiogenic signaling pathways in soft tissue models.

In a translational xenograft model using human adipose tissue, ADSC-Exos supplementation significantly improved 8-week volume retention (median 90.3 percent) compared to controls (median 59.5 percent, p=0.002). Histological analysis demonstrated enhanced neovascularization (CD31-positive vessel area 5.7 percent vs 1.1 percent; p<=0.001) and the study reported an anti-inflammatory shift, with reduced M1 proportions (8.4 percent vs 27.4 percent) and increased M2 proportions (69.7 percent vs 35.9 percent; all p<=0.001). Mechanistic literature links pro-angiogenic effects to pathways including PI3K-Akt in soft tissue contexts.

Translational evidence indicates ADSC-Exos improve retention and vascular integration of human fat grafts and promote a pro-regenerative macrophage shift in translational adipose models relevant to autologous breast reconstruction. Although breast-specific human clinical data remain limited and standardized isolation and dosing protocols are not yet established, current mechanistic and preclinical evidence supports further prospective investigation of exosome-assisted strategies in reconstructive breast surgery.

Skin wounds affect up to 2% of the population and impair quality of life. Bioactive glass releases biologically active ions that promote tissue regeneration and may enhance wound healing, particularly when combined with stem cells. This study evaluates the effects of bioactive glass on wound healing in an experimental swine model.

Two domestic swine (Sus scrofa domesticus) under general anesthesia underwent a surgical procedure to produce critical skin lesions (2 cm). The lesions were divided into four groups: Control Group (CG; no treatment, n = 8), Adipose-Derived Stem Cell Group (ASCG; 1 × 10ˆ8 cells, n = 8), Bioglass Group (BG; 1 mg bioglass, n = 8), and Bioglass + Adipose Stem Cell Group (BASCG; 1 mg bioglass + 1 × 10ˆ8 cells, n = 8). After the interventions, all wounds were covered with a transparent dressing, which was changed every three days for 30 postoperative days. At euthanasia, samples were collected for macroscopic and histological analyses (inflammatory cell count, angiogenesis, and dermal appendages) and for gene expression analysis (IL-1b, IL-10, CD68, and TNF-a).

On postoperative day 30, macroscopic evaluation demonstrated complete wound healing in 87.5% (7/8) of specimens in the BG and BASCG groups. Histological analysis showed a 32% reduction in inflammatory cell counts in the ASCG compared with the BASCG group (14.2 vs. 20.85; p = 0.022). Dermal appendage density was approximately threefold higher in all active treatment groups than in controls, with no significant differences among active groups. Angiogenesis did not differ significantly between groups, and no granuloma formation was observed. Gene expression analysis revealed significantly reduced CD68, TNF-a, and IL-1b levels in groups treated with bioglass and adipose-derived stem cells.

This study suggests that the use of bioglass associated with adipose-derived stem cells enhances wound healing by modulating the anti-inflammatory pathway. Further studies are warranted to confirm and expand upon these findings.

Adipose-derived therapies are increasingly explored for musculoskeletal regeneration. Adipose-derived stem cells (ADSCs) and stromal vascular fraction (SVF) may support repair via paracrine signaling, angiogenesis, and inflammation modulation. However, their regenerative effect in injured skeletal muscle remains uncertain. Given growing clinical interest, this study evaluated the histological effects of intramuscular injection of adipose tissue and its derivatives after controlled muscle injury.

A standardized muscle injury was induced in female Wistar rats by surgical resection of approximately 20% of the tibialis anterior muscle volume under general anesthesia. Animals were randomly allocated into five groups (n = 8 per group): injury only (control), injured muscle treated with macrofat, microfat, SVF or ADSCs. Each treatment group received 0.5 mL of the assigned preparation injected intramuscularly along the longitudinal axis of the muscle. After eight weeks, animals were euthanized and muscle samples were collected for histological analysis. Hematoxylin and eosin–stained sections were evaluated in 10 random fields at 20× and 40× magnification to assess cyst formation, fibrosis, inflammatory infiltration (macrophages and polymorphonuclear leukocytes), and vascular density (VD). Statistical analysis was performed using Kruskal–Wallis test followed by Dunn’s post hoc test when appropriate.

No significant differences were observed among groups for cyst formation (p = 0.83), fibrosis (p = 0.133), macrophage infiltration (p = 0.905), or polymorphonuclear leukocyte infiltration (p = 0.38). VD differed significantly across groups (Kruskal–Wallis, p = 0.0179). Dunn’s post hoc analysis demonstrated higher VD in the injury-only control group compared with the ADSC-treated group (17.44 vs. 6.93; p = 0.0198). No other significant pairwise differences were detected.

In this skeletal muscle injury model, intramuscular injection of adipose tissue and its derivatives did not significantly alter fibrosis, inflammation, or cyst formation. ADSC treatment showed lower vascular density than untreated injured muscle. These results indicate no enhancement of structural regeneration under the tested conditions and no additional histological benefit after acute injury. Further studies are needed to clarify functional implications and optimize muscle repair strategies.

Flap necrosis and graft failure remain significant sources of morbidity in reconstructive and aesthetic surgery, yet no cell-free biological adjunct has been established to improve tissue survival after transfer. Exosomes are nano-sized extracellular vesicles that are capable of simultaneously modulating angiogenesis, inflammation, apoptosis, and oxidative stress, and have emerged as promising regenerative adjuncts in plastic surgery.

This PROSPERO-registered systematic review and meta-analysis (CRD420251146650), conducted per PRISMA
2020, searched PubMed, OVID, Scopus, Web of Science, and Google Scholar through September 2025 and included 24 animal studies (19 flap; 5 skin graft). Flap and graft studies were analysed as separate populations.

Random-effects meta-analysis of flap studies demonstrated that exosomes significantly increased flap survival (k=19; MD 35.54%; 95% CI 25.11–45.97; p<0.0001) and angiogenesis (k=19; SMD 3.60; 95% CI 2.66–4.54; p<0.00001). Perfusion, VEGF expression, and apoptosis showed consistent improvements in narrative synthesis. Skin graft take improved significantly by days 10–14 in 4 of 5 studies, although certainty is low. Subgroup analysis suggested superior effects with human-derived and adipose-derived stem cell exosomes. However, substantial heterogeneity (I² 76–97%), funnel plot
asymmetry, and significant Egger’s tests indicate potential small-study effects and publication bias; the true treatment effect may be smaller than pooled estimates. Allocation concealment and blinding were unclear in most studies, further limiting confidence.

These preclinical findings support the biological rationale for exosome therapy in tissue transfer surgery and
provide a translational foundation for future standardized preclinical and early-phase clinical studies.

Fat graft retention remains unpredictable, partly due to variability in harvesting, processing, and especially cryopreservation protocols (1,2). Freezing and thawing can significantly reduce adipocyte and stromal vascular fraction viability, compromising proliferative potential and long-term graft survival (3-5) . Despite growing clinical use of cryopreserved fat, standardized preservation methods are lacking. This study evaluates the impact of different extraction and cryopreservation protocols on adipose tissue cellular viability and proliferative capacity.

Adipose tissue was harvested from lipoaspirates obtained from three healthy female donors. The samples were cryopreserved at −80 °C and stored for three, six, and twelve months. After each storage period, the specimens were thawed and systematically evaluated for cell viability and proliferative capacity. Comparative analyses were performed across different preservation conditions, including dimethyl sulfoxide (DMSO), Dulbecco’s Modified Eagle Medium (DMEM), trehalose, and a combined DMSO + trehalose protocol. In addition, histological assessment was conducted using the cell-block technique to evaluate tissue architecture and structural integrity after cryopreservation.

After three months of cryopreservation, the DMSO group demonstrated higher cell viability compared to the DMEM and trehalose groups. The DMSO + trehalose group showed comparable results. At six months, the highest viability rates were observed in the DMSO and DMSO + trehalose groups. After twelve months of cryopreservation, all groups exhibited an approximate 50% reduction in cell viability compared to fresh fat samples. Nevertheless, the DMSO + trehalose combination yielded results comparable to those obtained with DMSO or trehalose alone. Cell-block histological analysis demonstrated preservation of cellular architecture particularly in the DMSO + trehalose group.

This study demonstrates a reduction in cellular viability across all cryopreserved samples compared to fresh adipose tissue at all evaluated time points. Among the tested conditions, DMSO alone and DMSO combined with trehalose produced the most favorable viability outcomes. Further controlled studies are necessary to establish proof of concept and to validate these findings.

Endochondral ossification (ECO) is the principal mechanism of bone development and fracture repair. Adipose-derived stromal cells (ASCs) can be differentiated into hypertrophic cartilage tissues (HCTs) that subsequently remodel into bone organs in vivo. However, the factors governing successful remodeling leading to robust ECO remain incompletely understood. This study aimed to investigate the relationship between pre-implantation cartilage maturation, host-cells recruitment and bone remodeling in vivo for ASC-derived HCTs.

ASC-derived HCTs were generated from five donors using collagen scaffolds and cultured under chondrogenic conditions for 3, 5 or 7 weeks. After chondrogenic differentiation, grafts were matured in a growth factor-free Dulbecco's Modified Eagle Medium (DMEM) to prime the cartilage towards hypertrophy for either one or five weeks prior to subcutaneous implantation in immunodeficient mice for 4, 12 or 18 weeks. Individual grafts were monitored throughout in vitro maturation by quantification of glycosaminoglycan (GAG) release. Following explantation, grafts were analyzed by micro-computed tomography (micro-CT), histology and immunohistochemistry to assess tissue remodeling, vascularization, bone formation and bone marrow development. Flow cytometry was used to characterize host-recruited vascular, hematopoietic and remodeling-associated cell populations involved in the ECO process.

HCTs implanted after only three weeks of chondrogenic maturation displayed a fibrocartilaginous phenotype, underwent extensive resorption and failed to achieve robust ECO. In contrast, HCTs displaying an initial increase followed by sustained GAG release during in vitro maturation demonstrated reproducible and efficient ECO in vivo. Micro-CT and histological analyses revealed the formation of organized bone organs containing cortical bone, trabecular bone, and bone marrow cavities. Furthermore, HCTs subjected to an extended 5-week DMEM maturation phase prior to implantation retained robust bone-forming capacity and successfully underwent ECO in vivo.

ASC-derived HCTs can reproducibly generate bone organs through ECO when implanted at an appropriate maturation stage. GAG release profiles were strongly associated with successful remodeling outcomes and may serve as predictive in-process quality-control parameters. Importantly, HCTs maintained for up to five weeks in growth factor-free DMEM prior to implantation remained stable and preserved robust bone-forming capacity in vivo. This extended pre-implantation stability could provide valuable flexibility for manufacturing and surgical scheduling, thereby facilitating future translation of ECO-based bone regeneration strategies.

There is broad consensus that the initial management of severe burns includes complete debridement of affected skin. However, in patients with second-degree burns involving only small body surface areas, burn blisters have been hypothesized to function as a natural occlusive dressing that may support wound healing. This study aimed to evaluate the biological effects of burn blister fluid on key cellular processes involved in wound healing and to characterize its inflammatory and angiogenic mediator profile.

Blister fluid and corresponding serum samples were collected from patients with second - degree burns. Human dermal fibroblasts and human umbilical vein endothelial cells were exposed to diluted blister fluid or serum. Fibroblast metabolic activity and cytotoxicity were assessed using AlamarBlue® and LDH assays, respectively. Cell migration was evaluated using a scratch assay, while angiogenesis was assessed using an in vitro tube formation assay. Angiogenesis and inflammation arrays, as well as quantitative cytokine analyses, were performed to characterize soluble mediator profiles. Statistical analysis was performed using the Wilcoxon signed-rank test and correlation analyses.

Burn blister fluid significantly reduced fibroblast metabolic activity compared with serum (p = 0.012) and demonstrated increased cytotoxicity (p = 0.012), both with large effect sizes. No significant differences were observed between blister fluid - and serum -treated groups regarding fibroblast migration or angiogenesis. Angiogenesis array analysis identified CXCL1/2/3, RANTES, angiogenin, EGF, CXCL5, IL-6, IL-8, TIMP-1, and TIMP-2 in blister fluid, whereas PDGF-BB was additionally detected in serum. Compared with serum, blister fluid showed elevated levels of CXCL1/2/3, ENA-78, angiogenin, IL-6, and IL-8, with the largest differences observed for IL-6 and IL-8. Quantitative analyses demonstrated higher median IL-6 and IL-8 concentrations in blister fluid than in serum, although these differences did not reach statistical significance (IL-6: p = 0.086; IL-8: p = 0.063). No meaningful correlations were identified between interleukin levels and burned total body surface area.

Burn blister fluid exerts inhibitory and cytotoxic effects on fibroblasts in vitro while containing elevated levels of inflammatory mediators, particularly IL-6 and IL-8, without demonstrating measurable benefits for fibroblast migration or angiogenesis. These findings support the clinical practice of burn blister debridement during the primary management of burn injuries. Removal of burn blisters not only facilitates accurate assessment of burn depth but may also positively influence wound healing outcomes by eliminating a microenvironment enriched in pro-inflammatory mediators.