Self-Renewal and Differentiation of Adipose-Derived Stem Cells (ADSCs) Stimulated by Multi-Axial Tensile Strain in a Pneumatic Microdevice

High-Quality Lipoaspirate Following 1470-nm Radial Emitting Laser-Assisted Liposuction

BACKGROUND

Laser-assisted liposuction (LAL) has been used to maximize viable adipocyte yields in lipoaspirates, although optimizing tissue processing methods is still a challenge. A high-quality lipoaspirate has been a key factor for extended graft longevity.

OBJECTIVE

To assess the viability and potency of stromal vascular fraction (SVF) cells and adipose-derived stem cells (ASCs) in fat samples from lipoaspirates harvested with a novel 1470-nm diode, radial emitting LAL platform. Two processing methods, enzymatic and nonenzymatic, were compared.

METHODS

Laser-assisted liposuction lipoaspirates harvested from 10 subjects were examined for cell viability after processing by enzymatic or nonenzymatic methods. Isolated SVF cells were cultured with an ASC-permissive medium to assess their viability and proliferation capacity by cell proliferation assay. Flow cytometric analysis with ASC-specific markers, gene expression levels, and immunofluorescence for ASC transcription factors were also conducted.

RESULTS

Lipoaspirates showed high SVF cell viability of 97% ± 0.02% and 98% ± 0.01%, averaged SVF cell count of 8.7 × 10 6 ± 3.9 × 10 6 and 9.4 × 10 6 ± 4.2 × 10 6 cells per mL, and averaged ASC count of 1 × 10 6 ± 2.2 × 10 5 and 1.2 × 10 6 ± 5 × 10 5 cells per mL in nonenzymatic and enzymatic methods, respectively. The ASC-specific markers, gene expression levels, and immunofluorescence for ASC transcription factors confirmed the adipose origin of the cells.

CONCLUSIONS

The laser lipoaspirates provide a high yield of viable and potent SVF cells and ASCs through both nonenzymatic and enzymatic processes. Improved purity of the harvested lipoaspirate and high ASC content are expected to result in extended graft longevity. Furthermore, eliminating enzymatic digestion may provide advantages, such as reducing process time, cost, and regulatory constraints.

Aligned silk fibroin/poly-3-hydroxybutyrate nanofibrous scaffolds seeded with adipose-derived stem cells for tendon tissue engineering

In this work we investigated tenogenic differentiation of adipose-derived mesenchymal stem cells (AdMSCs), which were seeded onto silk fibroin/poly-3-hydroxybutyrate (SF/P3HB) scaffolds with aligned topography, and high mechanical strength. The electrospinning process was optimized by using the response surface method (RSM) and SF/P3HB nanofibrous matrices with a total polymer concentration of 5% (SF: PHB = 3: 1), flow rate 1 mL/h, collector rotation speed 2000 rpm, applied voltage 14 kV, and collector distance 25 cm were obtained. The average fiber diameter was 699 ± 203 nm and 80% of the nanofibers were aligned within the ±15^o range. SF reinforcement reduced the crystallinity of P3HB, and the elastic modulus was found to be 197.0 ± 7.7 MPa. The scaffolds showed bacteriostatic effect. A 21-day of cell culture study was performed with rat rAdMSCs in the absence and presence of tenogenic differentiation factor-5 (GDF-5). The results demonstrated that SF/P3HB scaffolds allow the cells to proliferate and differentiate to the tenocytes. However, no significant effect of GDF-5 on the differentiation of cells was observed. These findings indicated that our aligned SF/P3HB scaffolds have a significant potential to be used for tendon tissue engineering.

Adipose-Derived Stem Cells Secretome and Its Potential Application in "Stem Cell-Free Therapy"

Adipose-derived stem cells (ASCs) secrete many cytokines, proteins, growth factors, and extracellular vesicles with beneficial outcomes that can be used in regenerative medicine. It has great potential, and the development of new treatment strategies using the ASCs secretome is of global interest. Besides cytokines, proteins, and growth factors, the therapeutic effect of secretome is hidden in non-coding RNAs such as miR-21, miR-24, and miR-26 carried via exosomes secreted by adequate cells. The whole secretome, including ASC-derived exosomes (ASC-exos) has been proven in many studies to have immunomodulatory, proangiogenic, neurotrophic, and epithelization activity and can potentially be used for neurodegenerative, cardiovascular, respiratory, inflammatory, and autoimmune diseases as well as wound healing treatment. Due to limitations in the use of stem cells in cell-based therapy, its secretome with emphasis on exosomes seems to be a reasonable and safer alternative with increased effectiveness and fewer side effects. Moreover, the great advantage of cell-free therapy is the possibility of biobanking the ASCs secretome. In this review, we focus on the current state of knowledge on the use of the ASCs secretome in stem cell-free therapy.