Analysis of Adipose-Derived Stem Cells from Different Donor Areas and Their Influence on Fibroblasts In Vitro

Adipose-derived mesenchymal stromal cells in clinical trials: Insights from single-cell studies

Mesenchymal Stromal Cells (MSCs) offer tremendous potential for the treatment of various diseases and their healing properties have been explored in hundreds of clinical trials. These trails primarily focus on immunological and neurological disorders, as well as regenerative medicine. Adipose tissue is a rich source of mesenchymal stromal cells and methods to obtain and culture adipose-derived MSCs (AD-MSCs) have been well established. Promising results from pre-clinical testing of AD-MSCs activity prompted clinical trials that further led to the approval of AD-MSCs for the treatment of complex perianal fistulas in Crohn's disease and subcutaneous tissue defects. However, AD-MSC heterogeneity along with various manufacturing protocols or different strategies to boost their activity create the need for standardized quality control procedures and safety assessment of the intended cell product. High-resolution transcriptomic methods have been recently gaining attention, as they deliver insight into gene expression profiles of individual cells, helping to deconstruct cellular hierarchy and differentiation trajectories, and to understand cell-cell interactions within tissues. This article presents a comprehensive overview of completed clinical trials evaluating the safety and efficacy of AD-MSC treatment, together with current single-cell studies of human AD-MSC. Furthermore, our work emphasizes the increasing significance of single-cell research in elucidating the mechanisms of cellular action and predicting their therapeutic effects.

Evaluating Stromal Vascular Fraction As a Treatment for Peripheral Nerve Regeneration: A Scoping Review

PURPOSE

This study aims to investigate the potential of stromal vascular fraction (SVF) for peripheral nerve regeneration.

METHODS

A scoping review of Scopus and PubMed databases was conducted. Inclusion criteria were human or animal studies exploring the use of SVF for peripheral nerve regeneration. Studies were categorized by assessed outcomes: pain assessment, neural integrity, muscle recovery, and functional recovery. Level of evidence and study quality were assessed.

RESULTS

Nine studies met the inclusion criteria. SVF injection in humans with trigeminal neuropathic pain reduced pain scores from 7.5 ± 1.58 to 4.3 ± 3.28. SVF injection improved sensation in humans with leprosy neuropathy. Repairing transected rat sciatic nerves with SVF-coated nerve autografts improved wet muscle weight ratios (0.65 ± 0.11 vs 0.55 ± 0.06) and sciatic functional index (SFI) scores (-68.2 ± 9.2 vs -72.5 ± 8.9). Repairing transected rat sciatic nerves with SVF-coated conduits increased the ratio of gastrocnemius muscle weights (RGMW) (7-10% improvement), myelinated fibers (1,605 ± 806.2 vs 543.6 ± 478.66), and myelin thickness (5-20% increase). Repairing transected rat facial nerves with SVF-coated conduits improved whisker motion (9.22° ± 0.65° vs 1.90° ± 0.84°) and myelin thickness (0.57 μm ± 0.17 vs 0.45 μm ± 0.14 μm). Repairing transected rat sciatic nerves with SVF-coated nerve allografts improved RGMW (85 vs 50%), SFI scores (-20 to -10 vs -40 to -30), and Basso, Beatie, and Bresnahan locomotor scores (18 vs 15). All metrics mentioned above were statistically significant. The human studies were level 4 evidence due to being case series, while animal studies were the lowest level of evidence.

CONCLUSION

Despite initial promising results, the low-level evidence from the included studies warrants further investigation.

Effect of Donor Site Selection for Fat Grafting on the Yield and Viability of the Stromal Vascular Fraction

BACKGROUND

The efficacy of stromal vascular fraction (SVF) treatment, or stem cell treatment, directly depends on the SVF cell count and the cells' viability. The SVF cell count and viability are in direct correlation with the adipose tissue harvesting site that yields SVF cells, making this research a contribution to developing tissue guidance.

OBJECTIVES

The aim of this study was to investigate the importance of harvesting subcutaneous adipose tissue-derived SVF cells on the concentration and viability of SVF.

METHODS

Adipose tissue was collected by vibration-assisted liposuction from the regions of the upper and lower abdomen, lumbar region, and inner thigh region. With the semiautomatic UNISTATION 2nd Version system, the obtained fat was chemically processed (with collagenase enzyme) and a concentrate of SVF cells was obtained by centrifugation. These samples were then analyzed with the Luna-Stem Counter device to measure the number and viability of SVF cells.

RESULTS

When comparing the regions of the upper abdomen, lower abdomen, lumbar region, and inner thigh, the highest concentration of SVF was found in the lumbar region, specifically at an average of 97,498.00 per 1.0 mL of concentrate. The lowest concentration was found in the upper abdominal region. When ranking the viability values, the highest cell viability of SVF was observed in the lumbar region, measuring 36.6200%. The lowest viability was found in the upper abdominal region, measuring 24.4967%.

CONCLUSIONS

By comparing the upper and lower abdominal, lumbar, and inner thigh regions, the authors have come to the conclusion that, on average, the largest number of cells with the highest viability was obtained from the lumbar region.

Adipose-Derived Mesenchymal Stromal Cells in Basic Research and Clinical Applications

Adipose-derived mesenchymal stromal cells (AD-MSCs) have been extensively studied in recent years. Their attractiveness is due to the ease of obtaining clinical material (fat tissue, lipoaspirate) and the relatively large number of AD-MSCs present in adipose tissue. In addition, AD-MSCs possess a high regenerative potential and immunomodulatory activities. Therefore, AD-MSCs have great potential in stem cell-based therapies in wound healing as well as in orthopedic, cardiovascular, or autoimmune diseases. There are many ongoing clinical trials on AD-MSC and in many cases their effectiveness has been proven. In this article, we present current knowledge about AD-MSCs based on our experience and other authors. We also demonstrate the application of AD-MSCs in selected pre-clinical models and clinical studies. Adipose-derived stromal cells can also be the pillar of the next generation of stem cells that will be chemically or genetically modified. Despite much research on these cells, there are still important and interesting areas to explore.

Phenotypical Characterization and Neurogenic Differentiation of Rabbit Adipose Tissue-Derived Mesenchymal Stem Cells

Although the rabbit is a frequently used biological model, the phenotype of rabbit adipose-derived mesenchymal stem cells (rAT-MSCs) is not well characterized. One of the reasons is the absence of specific anti-rabbit antibodies. The study aimed to characterize rAT-MSCs using flow cytometry and PCR methods, especially digital droplet PCR, which confirmed the expression of selected markers at the mRNA level. A combination of these methods validated the expression of MSCs markers (CD29, CD44, CD73, CD90 and CD105). In addition, cells were also positive for CD49f, vimentin, desmin, α-SMA, ALDH and also for the pluripotent markers: NANOG, OCT4 and SOX2. Moreover, the present study proved the ability of rAT-MSCs to differentiate into a neurogenic lineage based on the confirmed expression of neuronal markers ENO2 and MAP2. Obtained results suggest that rAT-MSCs have, despite the slight differences in marker expression, the similar phenotype as human AT-MSCs and possess the neurodifferentiation ability. Accordingly, rAT-MSCs should be subjected to further studies with potential application in veterinary medicine but also, in case of their cryopreservation, as a source of genetic information of endangered species stored in the gene bank.

Effects of Harvest Sites on Cryopreserved Adipose-Derived Stem Cells and ASC-Enriched Fat Grafts

BACKGROUND

Enrichment of adipose-derived stem cells (ASCs) with fat grafts has demonstrated benefit for graft retention and histologic appearance. There is no consensus on the optimal harvest site for adipose-derived stem cells. This study aimed to investigate the effects of harvest sites on the characteristics of cryopreserved adipose-derived stem cells and the graft retention of cell-assisted lipotransfer.

METHODS

Lipoaspirates were harvested from 18 healthy volunteers who underwent liposuctions for body contouring. Twenty milliliters of lipoaspirates was, respectively, obtained from four sites, including the upper limb, abdomen, waist, and thighs, by the Coleman technique. Adipose-derived stem cells were ex vivo cultured and cryopreserved for four weeks. The biological characteristics of ASCs from four harvest sites were analyzed: MSC surface markers, cell proliferation, migration ability, and multipotential differentiation. The fat grafts were co-implanted with ASCs from four harvest sites and injected subcutaneously in mice. The ASC-enriched fat grafts were analyzed three months after transplantation.

RESULTS

Cryopreserved ASCs from the abdomen and thighs maintained more significant cell proliferation, migration ability, and differentiation potential, compared with cells from the upper limb and waist. Moreover, we achieved better graft retention of cell-assisted fat grafts with cryopreserved ASC from the abdomen and thighs.

CONCLUSIONS

The harvest site of adipose tissue affects the cellular activity and differentiation potential of cryopreserved ASCs. Improved understanding of harvest sites for ASCs can optimize the outcomes of cell-assisted fat grafts. Fat grafts enriched with cryopreserved ASCs from the abdomen or thighs are the optimal choices.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. 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 .

Mineralized Human Amniotic Membrane as a Biomimetic Scaffold for Hard Tissue Engineering Applications

The human amniotic membrane (HAM) has been viewed as a potential regenerative material for a wide variety of injured tissues because of its collagen-rich content. High degradability of HAM limits its wide practical application in bone tissue engineering. In this study, the natural matrix of the decellularized amniotic membrane was developed by the double diffusion method. The results confirmed a reduction of the amniotic membrane's degradability because of the deposition of calcium and phosphate ions during the double diffusion process. Real-time PCR results showed a high expression of osteogenesis-related genes from adipose-derived mesenchymal stem cells (ADMSCs) cultured on the surface of the developed mineralized amniotic membrane (MAM). Further in vivo experiments were conducted using an MAM preseeded with ADMSCs and a critical-size rat calvarial defect model. Histopathological results confirmed that the MAM + cell sample has excellent potential in bone regeneration.