This work was partially supported by the National Natural Science Foundation of China (82202473).

The overview of the protocol steps is shown in Figure 1. The details of the reagents and equipment used in the study are listed in the Table of Materials.
1. Media preparation
<ol>
	<li>Prepare a culture medium for ADSC without exosomes using 450 mL of basal culture medium, 50 mL of fetal bovine serum without exosomes, and 5 mL of triple antibiotics.</li>
</ol>
2. Resuscitating and culturing ADSCs
NOTE: Resuscitate ADSCs.
<ol>
	<li>Turn on the UV radiation of the ultra-clean table beforehand and disinfect it for 30 min.</li>
	<li>Preheat the medium in a 37 &#176;C water bath beforehand.</li>
	<li>Retrieve 2 tubes of frozen ADSCs (P3) from liquid nitrogen and agitate them in a 37 &#176;C water bath with constant temperature until fully thawed. 
	NOTE: The opening of the freezer tube should not be in contact with water to prevent contamination.</li>
	<li>Disinfect the cryopreservation tube using 75% alcohol and then move it to the ultra-clean table. Aspirate the cell suspension using a pipette and place it in a 15 mL centrifuge tube.</li>
	<li>Place the centrifuge tube into a low-speed centrifuge machine and centrifuge at 250 x g for 5 min at 4 &#176;C.</li>
	<li>Prepare four 10 cm culture dishes and put 9 mL of medium into each dish. Mark the name, cell type, generation, and experimental date, and then preheat them in a 37 &#176;C thermostatic cell incubator.</li>
	<li>Disinfect the centrifuge tube and move it to the ultra-clean table. Remove the supernatant with a pipette.</li>
	<li>Add 4 mL of medium and gently agitate the solution (1 x 105 cells/mL) until it is evenly dispersed. 
	NOTE: Take care not to eliminate the cell pellet when extracting the supernatant.</li>
	<li>Add 1 mL of cell suspension to each dish. Shake the dishes with a cross method. 
	NOTE: Position the plate on a level surface and agitate it in a cross pattern (moving it up, down, left, and right) for 5-6 repetitions. Avoid circular motions, as they may cause cell accumulation in the center.</li>
	<li>Observe the cells at 40x magnification with the optical microscope, and then place the dishes into the incubator. 
	NOTE: The primary purpose of observing the cells is to determine if they are evenly distributed, as uneven distribution will affect subsequent growth.</li>
	<li>Prepare exchange medium for the cells.
	<ol>
		<li>Turn on the UV radiation of the ultra-clean table beforehand and disinfect it for 30 min.</li>
		<li>Preheat the medium in a 37 &#176;C water bath beforehand.</li>
		<li>Observe the cell state under the optical microscope at 40x magnification. The confluence level is approximately 50%. 
		NOTE: The confluence level is calculated as the ratio of the area occupied by the cells to the surface area of the petri dish after the cells adhere to the wall and fully stretch.</li>
		<li>Transfer the culture dish to the ultra-clean table (Biosafety level 2) after disinfection and remove the medium.</li>
		<li>Rinse each culture dish twice with 2 mL of PBS solution gently.</li>
		<li>Add 10 mL of medium to each dish. Transfer the dishes to the incubator.</li>
	</ol>
	</li>
</ol>
3. Collecting the ADSCs supernatant and extracting the EVs
<ol>
	<li>Turn on the UV radiation of the ultra-clean table beforehand and disinfect it for 30 min.</li>
	<li>Observe the cell state under a microscope. The confluence level is approximately 80%.</li>
	<li>Transfer the dish to the ultra-clean table after disinfection. Carefully collect the supernatant with a pipette and place it in a 50 mL centrifuge tube. 
	NOTE: Cells can be either frozen or discarded. If sterility is not required, the following steps can be performed on the operating table. At this point, the experiment can be paused and then restarted later. If the experiment is halted, store the supernatant in a 4 &#176;C refrigerator for not more than one week. Long-term storage is not recommended as it may affect the activity of EVs. The optimal approach is to extract EVs immediately.</li>
	<li>Centrifuge (300 x g, 10 min, at room temperature) to remove suspended cells. Collect the supernatant with a pipette. 
	NOTE: Do not pour. Leave a little supernatant to prevent the pellet from being sucked up.</li>
	<li>Centrifuge to remove cellular debris (2000 x g, 10 min, 4 &#176;C), then continue to collect the supernatant with a pipette. 
	NOTE: The key points are the same as in step 3.4.</li>
	<li>Filter the supernatant with a 0.22 um membrane to remove large particles and cell debris. 
	NOTE: Filter the supernatant with 2 mL of sterile PBS to moisten the filter membrane prior to filtration.</li>
	<li>Centrifuge in the ultracentrifuge machine (10,000 x g, 30 min, 4 &#176;C).</li>
	<li>Next, centrifuge at 1,00,000 x g for 70 min at 4 &#176;C to remove the pellet and collect the supernatant. 
	NOTE: The obtained EVs were purified by centrifugation multiple times to increase their purity. The pellet may not be visible to the naked eye. Therefore, it is crucial to operate the pipette gently and to leave a little supernatant at the bottom to avoid pellet collection.</li>
	<li>Remove the supernatant with a pipette. Resuspend the pellet with PBS and centrifuge (1,00,000 x g, 70 min, 4 &#176;C). 
	NOTE: The pellet may not be visible to the naked eye. Therefore, when aspirating the supernatant with a pipette, it is critical to gently and thoroughly remove the supernatant to maximize the purity of EVs.</li>
	<li>Remove the supernatant and obtain the EVs pellet. Resuspend it with 1 mL of PBS, transfer it into a 1 mL centrifuge tube, and store it in a 4 &#176;C refrigerator for subsequent detection. 
	NOTE: The pellet may not be visible to the naked eye. Consequently, when aspirating the supernatant with a pipette, it is crucial to gently and thoroughly remove the supernatant to maximize EVs purity. If the samples are not needed for an extended period, store them in a -80 &#176;C refrigerator.</li>
</ol>

Ultracentrifuge-Based Isolation of Extracellular Vesicles from Human ADSCs

<ol>
	<li>Al-Ghadban, S., Artiles, M., Bunnell, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+stem+cells+in+regenerative+medicine:+Looking+forward.">Adipose stem cells in regenerative medicine: Looking forward.</a> Front Bioeng Biotechnol. 9, 837464 (2021).</li><li>Xin, H., Li, Y., Chopp, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exosomes/miRNAs+as+mediating+cell-based+therapy+of+stroke.">Exosomes/miRNAs as mediating cell-based therapy of stroke.</a> Front Cell Neurosci. 8, 377 (2014).</li><li>Li, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+tissue+origin+effect+of+extracellular+vesicles+on+cartilage+and+bone+regeneration.">The tissue origin effect of extracellular vesicles on cartilage and bone regeneration.</a> Acta Biomater. 125, 253-266 (2021).</li><li>Gao, X., Salomon, C., Freeman, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+vesicles+from+adipose+tissue-a+potential+role+in+obesity+and+type+2+diabetes.">Extracellular vesicles from adipose tissue-a potential role in obesity and type 2 diabetes.</a> Front Endocrinol (Lausanne). 8, 202 (2017).</li><li>Zheng, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+and+biological+effects+of+extracellular+vesicles+from+adipose-derived+stem+cells+were+markedly+increased+by+low-intensity+ultrasound+stimulation+for+promoting+diabetic+wound+healing).">Production and biological effects of extracellular vesicles from adipose-derived stem cells were markedly increased by low-intensity ultrasound stimulation for promoting diabetic wound healing).</a> Stem Cell Rev Rep. 19 (3), 784-806 (2023).</li><li>Mou, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+vesicles+from+human+adipose-derived+stem+cells+for+the+improvement+of+angiogenesis+and+fat-grafting+application.">Extracellular vesicles from human adipose-derived stem cells for the improvement of angiogenesis and fat-grafting application.</a> Plast Reconstr Surg. 144 (4), 869-880 (2019).</li><li>Li, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue-engineered+bone+immobilized+with+human+adipose+stem+cells-derived+exosomes+promotes+bone+regeneration.">Tissue-engineered bone immobilized with human adipose stem cells-derived exosomes promotes bone regeneration.</a> ACS Appl Mater Interfaces. 10 (6), 5240-5254 (2018).</li><li>Han, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose-derived+stem+cell-derived+extracellular+vesicles+inhibit+the+fibrosis+of+fibrotic+buccal+mucosal+fibroblasts+via+the+microRNA-375/foxf1+axis.">Adipose-derived stem cell-derived extracellular vesicles inhibit the fibrosis of fibrotic buccal mucosal fibroblasts via the microRNA-375/foxf1 axis.</a> Stem Cells Int. 2021, 9964159 (2021).</li><li>Brezgin, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technological+aspects+of+manufacturing+and+analytical+control+of+biological+nanoparticles.">Technological aspects of manufacturing and analytical control of biological nanoparticles.</a> Biotechnol Adv. 64, 108122 (2023).</li><li>Kim, S. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Character+comparison+of+abdomen-derived+and+eyelid-derived+mesenchymal+stem+cells.">Character comparison of abdomen-derived and eyelid-derived mesenchymal stem cells.</a> Cell Prolif. 46 (3), 291-299 (2013).</li><li>Gan, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exosomes+from+adipose-derived+mesenchymal+stem+cells+improve+liver+fibrosis+by+regulating+the+miR-20a-5p/TGFBR2+axis+to+affect+the+p38+MAPK/NF-&#954;B+pathway.">Exosomes from adipose-derived mesenchymal stem cells improve liver fibrosis by regulating the miR-20a-5p/TGFBR2 axis to affect the p38 MAPK/NF-&#954;B pathway.</a> Cytokine. 172, 156386 (2023).</li><li>Jung, M. K., Mun, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sample+preparation+and+imaging+of+exosomes+by+transmission+electron+microscopy.">Sample preparation and imaging of exosomes by transmission electron microscopy.</a> J Vis Exp. (131), e56482 (2018).</li><li>Han, Y. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Co-transplantation+of+exosomes+derived+from+hypoxia-preconditioned+adipose+mesenchymal+stem+cells+promotes+neovascularization+and+graft+survival+in+fat+grafting.">Co-transplantation of exosomes derived from hypoxia-preconditioned adipose mesenchymal stem cells promotes neovascularization and graft survival in fat grafting.</a> Biochem Biophys Res Commun. 497 (1), 305-312 (2018).</li><li>Linares, R., Tan, S., Gounou, C., Arraud, N., Brisson, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-speed+centrifugation+induces+aggregation+of+extracellular+vesicles.">High-speed centrifugation induces aggregation of extracellular vesicles.</a> J Extracell Vesicles. 4, 29509 (2015).</li><li>Lamparski, H. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+and+characterization+of+clinical+grade+exosomes+derived+from+dendritic+cells.">Production and characterization of clinical grade exosomes derived from dendritic cells.</a> J Immunol Methods. 270 (2), 211-226 (2002).</li><li>Baranyai, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+exosomes+from+blood+plasma:+Qualitative+and+quantitative+comparison+of+ultracentrifugation+and+size+exclusion+chromatography+methods.">Isolation of exosomes from blood plasma: Qualitative and quantitative comparison of ultracentrifugation and size exclusion chromatography methods.</a> PLoS One. 10 (12), e0145686 (2015).</li><li>Yuan, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+extracellular+vesicles+by+three-dimensional+dynamic+culture+of+human+mesenchymal+stem+cells.">Engineering extracellular vesicles by three-dimensional dynamic culture of human mesenchymal stem cells.</a> J Extracell Vesicles. 11 (6), e12235 (2022).</li><li>Eguchi, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organoids+with+cancer+stem+cell-like+properties+secrete+exosomes+and+HSP90+in+a+3D+nanoenvironment.">Organoids with cancer stem cell-like properties secrete exosomes and HSP90 in a 3D nanoenvironment.</a> PLoS One. 13 (2), e0191109 (2018).</li></ol>

The authors have no financial interest to declare.

During the formal experimental process, several points are crucial for achieving the best experimental results. Based on our previous experience, it is recommended to opt for passage 3-6 ADSCs, as they ensure the best possible cell state. Before P3, red blood cells, endothelial cells, and other miscellaneous cells may not have been screened out. After P6, the cells may gradually age, which can affect the state of secreted EVs. Secondly, the supernatant must be collected when the cell confluence degree is between 80% and ...

Most ADSCs are derived from adipose tissue and have been demonstrated to promote the regeneration and reconstruction of various tissues and organs, including the myocardium, bone, and skin1. Recent research suggests that the regenerative function of ADSCs may be due to intercellular contact and the paracrine effects of the cells2. The paracrine effect is an important means for cells to interact and transfer information over short distances, and this function is achieved through extracellular vesicles (EVs).
EVs are double-layer membrane structures produced by cells, with a diameter ranging from 40 nm to 160 nm (with an average of about 100 nm). They affect different cellular functions, such as cytokine production, cell proliferation, apoptosis, and metabolism3,4. Numerous studies have been conducted on the functions of ADSC EVs, including promoting bone regeneration, oral mucosal tissue regeneration, adipose tissue survival after tissue transplantation, and skin wound repair5,6,7,8. The enormous potential of ADSC EVs in regenerative medicine is evident. Various methods exist for extracting and separating EVs from the supernatant, such as techniques based on centrifugation, precipitation, molecular size, affinity, and microfluidics. The ultracentrifugation method is widely considered the gold standard for isolating EVs9. The fundamental principle of ultracentrifugation for EV separation is based on the fact that particles in the sample have varying sedimentation coefficients, resulting in their sedimentation and aggregation in distinct separation layers. Nevertheless, a detailed protocol emphasizing precautions during ultracentrifugation has not yet been established.
Therefore, this study objectively outlines the ADSC culture, supernatant collection, and EVs ultracentrifugation procedures and key points with a logical flow of information and clear, formal language. This provides a valuable reference for future experiments.

<table><tbody><tr><td>Acrodisc Needle Filter of Supor Membrane</td><td>Acros Organics</td><td>4652</td><td>0.22 &amp;mu;m</td></tr><tr><td>Basal Medium For Cell Culture</td><td>OriCell</td><td>BHDM-03011</td><td></td></tr><tr><td>Fetal Bovine Serum Without EXO + Culture Supplement (For Human Adipose-derived Mesenchymal Stem Cells)</td><td>OriCell</td><td>HUXMD-05002</td><td></td></tr><tr><td>Inverted Microscope</td><td>OLYMPUS</td><td>Lx70-S8F2</td><td></td></tr><tr><td>Low Speed Centrifuge</td><td>Anhui USTC Zonkia Scientific Instruments Co.,Ltd.</td><td>SC-3612</td><td></td></tr><tr><td>Normocin</td><td>InvivoGen</td><td>ant-nr-05</td><td></td></tr><tr><td>Optima Max-XP Tabletop Ultracentrifuge</td><td>Beckman Coulter</td><td>393315</td><td></td></tr><tr><td>Penicillin-Streptomycin-Gentamicin Solution (100x)</td><td>Solarbio</td><td>P1410</td><td></td></tr></tbody></table>

purification and characterization of extracellular vesicles from human adipose-derived mesenchymal stem cells

Human adipose-derived mesenchymal stem cells (ADSCs) can promote the regeneration and reconstruction of various tissues and organs. Recent research suggests that their regenerative function may be attributed to cell-cell contact and cell paracrine effects. The paracrine effect is an important way for cells to interact and transfer information over short distances, in which extracellular vesicles (EVs) play a functional role as carriers. There is significant potential for ADSC EVs in regenerative medicine. Multiple studies have reported on the effectiveness of these methods. Various methods for extracting and isolating EVs are currently described based on principles such as centrifugation, precipitation, molecular size, affinity, and microfluidics. Ultracentrifugation is regarded as the gold standard for isolating EVs. Nevertheless, a meticulous protocol to highlight precautions during ultracentrifugation is still absent. This study presents the methodology and crucial steps involved in ADSC culture, supernatant collection, and EV ultracentrifugation. However, even though ultracentrifugation is cost-effective and requires no further treatment, there are still some inevitable drawbacks, such as a low recovery rate and EV aggregation.

Firstly, ADSCs were characterized and identified, including their morphology10 and surface antibodies. Based on Figure 2A, it is apparent that ADSCs are arranged in a spindle shape and form a vortex after dense growth. The cultured cells were differentiated into adipogenic, osteogenic, and chondrogenic cells and stained with Oil Red O, Alizarin Red, and Alcian Blue11. The induced differentiation experiment and flow cytometry validated that they...

Read this Scientific Article Protocol about Author Spotlight: Standardizing and Improving the Extraction and Purification of Extracellular Vesicles from Human ADSCs at JoVE.com

Author Spotlight: Standardizing and Improving the Extraction and Purification of Extracellular Vesicles from Human ADSCs

This protocol describes all procedures, from culturing human adipose-derived mesenchymal stem cells (ADSCs) and collecting supernatant to extracting extracellular vesicles (EVs) using ultracentrifugation.

Purification and Characterization of Extracellular Vesicles from Human Adipose-Derived Mesenchymal Stem Cells

Human adipose-derived mesenchymal stem cells (ADSCs) can promote the regeneration and reconstruction of various tissues and organs. Recent research ...

purification-characterization-extracellular-vesicles-from-human

Research

JoVE Journal

Medicine

567 Views.  Chinese PLA General Hospital. This protocol describes all procedures, from culturing human adipose-derived mesenchymal stem cells (ADSCs) and collecting supernatant to extracting extracellular vesicles (EVs) using ultracentrifugation.

Video: Author Spotlight: Standardizing and Improving the Extraction and Purification of Extracellular Vesicles from Human ADSCs

Manual Isolation of Adipose-derived Stem Cells from Human Lipoaspirates

In 2001, researchers at the University of California, Los Angeles, described the isolation of a new population of adult stem cells from liposuctioned adipose tissue that they initially termed Processed Lipoaspirate Cells or PLA cells. Since then, these stem cells have been renamed as Adipose-derived Stem Cells or ASCs and have gone on to become one of the most popular adult stem cells populations in the fields of stem cell research and regenerative medicine. Thousands of articles now describe the use of ASCs in a variety of regenerative animal models, including bone regeneration, peripheral nerve repair and cardiovascular engineering. Recent articles have begun to describe the myriad of uses for ASCs in the clinic. The protocol shown in this article outlines the basic procedure for manually and enzymatically isolating ASCs from large amounts of lipoaspirates obtained from cosmetic procedures. This protocol can easily be scaled up or down to accommodate the volume of lipoaspirate and can be adapted to isolate ASCs from fat tissue obtained through abdominoplasties and other similar procedures.

In 2001, researchers at UCLA described the isolation of a population of adult stem cells, termed Adipose-derived Stem Cells or ASCs, from adipose tissue. This article outlines the isolation of ASCs from lipoaspirates using a manual, enzymatic digestion protocol using collagenase.

In 2001, researchers at the University of  California, Los Angeles, described the isolation of a new population of adult  stem cells from liposuctioned ...

Biology

An Enzyme-free Method for Isolation and Expansion of Human Adipose-derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are a population of multipotent cells that can be isolated from various adult and fetal tissues, including adipose tissue. As a clinically relevant cell type, optimal methods are needed to isolate and expand these cells in vitro. Most methods to isolate adipose-derived MSCs (ADSCs) rely on harsh enzymes, such as collagenase, to digest the adipose tissue. However, while effective at breaking down the adipose tissue and yielding a high ADSC recovery, these enzymes are expensive and can have detrimental effect on the ADSCs &#8212; including the risks of using xenogeneic components in clinical applications. This protocol details a method to isolate ADSCs from fresh lipoaspirate and abdominoplasty samples without enzymes. Briefly, this method relies on mechanical disassociation of any bulk tissue followed by an explant-type culture system. The ADSCs are permitted to migrate out of tissue and onto the tissue culture plate, after which the ADSCs can be cultured and expanded in vitro for any number of research and/or clinical applications.

This protocol provides an enzyme-free method for isolating mesenchymal stem cells from abdominoplasty and lipoaspirate samples using an explant method. The absence of harsh enzymes or centrifugation steps provides for clinically relevant stem cells that can be used for studies in vitro or transferred back to the clinic.

Mesenchymal stem cells (MSCs) are a population of multipotent cells that can be isolated from various adult and fetal tissues, including adipose tissue. ...

Technique for Obtaining Mesenchymal Stem Cell from Adipose Tissue and Stromal Vascular Fraction Characterization in Long-Term Cryopreservation

Human mesenchymal stem cells derived from adipose tissue have become increasingly attractive as they show appropriate features and are an accessible source for regenerative clinical applications. Different protocols have been used to obtain adipose-derived stem cells. This article describes different steps of an improved time-saving protocol to obtain a more significant amount of ADSC, showing how to cryopreserve and thaw ADSC to obtain viable cells for culture expansion. One hundred milliliters of lipoaspirate were collected, using a 26 cm three-hole and 3 mm caliber syringe liposuction, from the abdominal area of nine patients who subsequently underwent elective abdominoplasty. The stem cells isolation was carried out with a series of washes with Dulbecco&#39;s Phosphate Buffered Saline (DPBS) solution supplemented with calcium and the use of collagenase. Stromal Vascular Fraction (SVF) cells were cryopreserved, and their viability was checked by immunophenotyping. The SVF cellular yield was 15.7 x 105 cells/mL, ranging between 6.1-26.2 cells/mL. Adherent SVF cells reached confluence after an average of 7.5 (&#177;4.5) days, with an average cellular yield of 12.3 (&#177; 5.7) x 105 cells/mL. The viability of thawed SVF after 8 months, 1 year, and 2 years ranged between 23.06%-72.34% with an average of 47.7% (&#177;24.64) with the lowest viability correlating with cases of two-year freezing. The use of DPBS solution supplemented with calcium and bag resting times for fat precipitation with a shorter time of collagenase digestion resulted in an increased stem cell final cellular yield. The detailed procedure for obtaining high yields of viable stem cells was more efficient regarding time and cellular yield than the techniques from previous studies. Even after a long period of cryopreservation, viable ADSC cells were found in the SVF.

The present protocol describes an improved methodology for ADSC isolation resulting in a tremendous cellular yield with time gain compared to the literature. This study also provides a straightforward method for obtaining a relatively large number of viable cells after long-term cryopreservation.

Human mesenchymal stem cells derived from adipose tissue have become increasingly attractive as they show appropriate features and are an accessible ...

Human Adipose Tissue Micro-fragmentation for Cell Phenotyping and Secretome Characterization

In the past decade, adipose tissue transplants have been widely used in plastic surgery and orthopaedics to enhance tissue repletion and/or regeneration. Accordingly, techniques for harvesting and processing human adipose tissue have evolved in order to quickly and efficiently obtain large amounts of tissue. Among these, the closed system technology represents an innovative and easy-to-use system to harvest, process, and re-inject refined fat tissue in a short time and in the same intervention (intra-operatively). Adipose tissue is collected by liposuction, washed, emulsified, rinsed and minced mechanically into cell clusters of 0.3 to 0.8 mm. Autologous transplantation of mechanically fragmented adipose tissue has shown remarkable efficacy in different therapeutic indications such as aesthetic medicine and surgery, orthopedic and general surgery. Characterization of micro-fragmented adipose tissue revealed the presence of intact small vessels within the adipocyte clusters; hence, the perivascular niche is left unperturbed. These clusters are enriched in perivascular cells (i.e., mesenchymal stem cell (MSC) ancestors) and in vitro analysis showed an increased release of growth factors and cytokines involved in tissue repair and regeneration, compared to enzymatically derived MSCs. This suggests that the superior therapeutic potential of microfragmented adipose tissue is explained by a higher frequency of presumptive MSCs and enhanced secretory activity. Whether these added pericytes directly contribute to higher growth factor and cytokine production is not known. This clinically approved procedure allows the transplantation of presumptive MSCs without the need for expansion and/or enzymatic treatment, thus bypassing the requirements of GMP guidelines, and reducing the costs for cell-based therapies.

Here, we present human adipose tissue enzyme-free micro-fragmentation using a closed system device. This new method allows the obtainment of sub-millimeter clusters of adipose tissue suitable for in vivo transplantation, in vitro culture, and further cell isolation and characterization.

In the past decade, adipose tissue transplants have been widely used in plastic surgery and orthopaedics to enhance tissue repletion and/or regeneration. ...

Isolation and Characterization of Human Adipocyte-Derived Extracellular Vesicles using Filtration and Ultracentrifugation

Extracellular vesicles (EVs) are lipid enclosed envelopes that carry biologically active material such as proteins, RNA, metabolites and lipids. EVs can modulate the cellular status of other cells locally in tissue microenvironments or through liberation into peripheral blood. Adipocyte-derived EVs are elevated in the peripheral blood and show alterations in their cargo (RNA and protein) during metabolic disturbances, including obesity and diabetes. Adipocyte-derived EVs can regulate the cellular status of neighboring vascular cells, such as endothelial cells and adipose tissue resident macrophages to promote adipose tissue inflammation. Investigating alterations in adipocyte-derived EVs in vivo is complex because EVs derived from peripheral blood are highly heterogenous and contain EVs from other sources, namely platelets, endothelial cells, erythrocytes and muscle. Therefore, the culture of human adipocytes provides a model system for the study of adipocyte derived EVs. Here, we provide a detailed protocol for the extraction of total small EVs from cell culture media of human gluteal and abdominal adipocytes using filtration and ultracentrifugation. We further demonstrate the use of Nanoparticle Tracking Analysis (NTA) for quantification of EV size and concentration and show the presence of EV-protein tumor susceptibility gene 101 (TSG101) in the gluteal and abdominal adipocyte derived-EVs. Isolated EVs from this protocol can be used for downstream analysis, including transmission electron microscopy, proteomics, metabolomics, small RNA-sequencing,&#160;microarrays and can be&#160;utilized in functional in vitro/in vivo studies.

We describe the isolation of human adipocyte-derived extracellular vesicles (EVs) from gluteal and abdominal adipose tissue using filtration and ultracentrifugation. We characterize the isolated adipocyte-derived EVs by determining their size and concentration by Nanoparticle Tracking Analysis and by western blotting for the presence of EV-protein tumor susceptibility gene 101 (TSG101).

Extracellular vesicles (EVs) are lipid enclosed envelopes that carry biologically active material such as proteins, RNA, metabolites and lipids. EVs can ...

A Simple Benchtop Filtration Method to Isolate Small Extracellular Vesicles from Human Mesenchymal Stem Cells

The ultracentrifugation-based process is considered the common method for small extracellular vesicles (sEVs) isolation. However, the yield from this isolation method is relatively lower, and these methods are inefficient in separating sEV subtypes. This study demonstrates a simple benchtop filtration method to isolate human umbilical cord-derived MSC small extracellular vesicles (hUC-MSC-sEVs), successfully separated by ultrafiltration from the conditioned medium of hUC-MSCs. The size distribution, protein concentration, exosomal markers (CD9, CD81, TSG101), and morphology of the isolated hUC-MSC-sEVs were characterized with nanoparticle tracking analysis, BCA protein assay, western blot, and transmission electron microscope, respectively. The isolated hUC-MSC-sEVs&#39; size was 30-200 nm, with a particle concentration of 7.75 &#215; 1010 particles/mL and a protein concentration of 80 &#181;g/mL. Positive bands for exosomal markers CD9, CD81, and TSG101 were observed. This study showed that hUC-MSC-sEVs were successfully isolated from hUC-MSCs conditioned medium, and characterization showed that the isolated product fulfilled the criteria mentioned by Minimal Information for Studies of Extracellular Vesicles 2018 (MISEV 2018).

This protocol demonstrates how to isolate human umbilical cord-derived mesenchymal stem cells&#39; small extracellular vesicles (hUC-MSC-sEVs) with a simple lab-scale benchtop setting. The size distribution, protein concentration, sEVs markers, and morphology of isolated hUC-MSC-sEVs are characterized by nanoparticle tracking analysis, BCA protein assay, western blot, and transmission electron microscope, respectively.

The ultracentrifugation-based process is considered the common method for small extracellular vesicles (sEVs) isolation. However, the yield from this ...

Isolation, Characterization, and Therapeutic Application of Extracellular Vesicles from Cultured Human Mesenchymal Stem Cells

Extracellular vesicles (EVs) are heterogeneous membrane nanoparticles released by most cell types, and they are increasingly recognized as physiological regulators of organismal homeostasis and important indicators of pathologies; in the meantime, their immense potential to establish accessible and controllable disease therapeutics is emerging. Mesenchymal stem cells (MSCs) can release large amounts of EVs in culture, which have shown promise to jumpstart effective tissue regeneration and facilitate extensive therapeutic applications with good scalability and reproducibility. There is a growing demand for simple and effective protocols for collecting and applying MSC-EVs. Here, a detailed protocol is provided based on differential centrifugation to isolate and characterize representative EVs from cultured human MSCs, exosomes, and microvesicles for further applications. The adaptability of this method is shown for a series of downstream approaches, such as labeling, local transplantation, and systemic injection. The implementation of this procedure will address the need for simple and reliable MSC-EVs collection and application in translational research.

The present protocol describes the differential centrifugation for isolating and characterizing representative EVs (exosomes and microvesicles) from cultured human MSCs. Further applications of these EVs are also explained in this article.

Extracellular vesicles (EVs) are heterogeneous membrane nanoparticles released by most cell types, and they are increasingly recognized as physiological ...

Adipose Tissue-Derived Stem Cell Isolation and Characterization

Isolation and Identification of Mesenchymal Stem Cells Derived from Adipose Tissue of Sprague Dawley Rats

Adult mesenchymal cells have revolutionized molecular and cell biology in recent decades. They can differentiate into different specialized cell types, in addition to their great capacity for self-renewal, migration, and proliferation. Adipose tissue is one of the least invasive and most accessible sources of mesenchymal cells. It has also been reported to have higher yields compared to other sources, as well as superior immunomodulatory properties. Recently, different procedures for obtaining adult mesenchymal cells from different tissue sources and animal species have been published. After evaluating the criteria of some authors, we standardized a methodology that is applicable to different purposes and easily reproducible. A pool of stromal vascular fraction (SVF) from perirenal and epididymal adipose tissue allowed us to develop primary cultures with optimal morphology and functionality. The cells were observed adhered to the plastic surface for 24 h, and exhibited a fibroblast-like morphology, with prolongations and a tendency to form colonies. Flow cytometry (FC) and immunofluorescence (IF) techniques were used to assess the expression of the membrane markers CD105, CD9, CD63, CD31, and CD34. The ability of adipose-derived stem cells (ASCs) to differentiate into the adipogenic lineage was also assessed using a cocktail of factors (4 &#181;M insulin, 0.5 mM 3-methyl-iso-butyl-xanthine, and 1 &#181;M dexamethasone). After 48 h, a gradual loss of fibroblastoid morphology was observed, and at 12 days, the presence of lipid droplets positive to oil red staining was confirmed. In summary, a procedure is proposed to obtain optimal and functional ASC cultures for application in regenerative medicine.

Author Spotlight: Isolation and Identification of Mesenchymal Stem Cells Derived from Adipose Tissue of Sprague Dawley Rats  

This protocol describes a methodology for isolating and identifying adipose tissue-derived mesenchymal stem cells (MSCs) from Sprague Dawley rats.

Adult mesenchymal cells have revolutionized molecular and cell biology in recent decades. They can differentiate into different specialized cell types, in ...

Primary Culture of Adipose Tissue Derived Stem Cells from Mouse Epididymis

Isolation, In Vitro Expansion, and Characterization of Mesenchymal Stem Cells from Mouse Epididymal Adipose Tissue

Mesenchymal stem cells (MSCs) have been extensively studied as a new therapeutic approach, mainly to stop exacerbated inflammation due to their potential to modulate the immune response. The MSCs are immune-privileged cells capable of surviving in immunologically incompatible allogeneic transplant recipients based on low expression of class I major histocompatibility complex (MHC) molecules and in the use of cell-based therapy for allogeneic transplant. These cells can be isolated from several tissues, the most commonly used being the bone marrow and adipose tissues. We provide an easy protocol to isolate, culture, and characterize MSCs from epididymal adipose tissue of mice. The epididymal adipose tissue is surgically excised, physically fragmented, and digested with 0.15% collagenase type II solution. Then, primary adipose tissue-derived stem (ADSCs) cells are cultured and expanded in vitro, and the phenotypic characterization is performed by flow cytometry. We also provide the steps to differentiate the ADSCs into osteogenic, adipogenic, and chondrogenic cells, followed by functional characterization of each cell lineage. The protocol provided here can be used for in vivo and ex vivo experiments, and as an alternative, the adipose-derived stem cells can be used to generate MSCs-like immortalized cells.

Author Spotlight: Advancing Treatment Approaches with Adipose-Derived Stem Cells

The adipose tissue is an excellent source of mesenchymal stem cells. Here, we bring the step-by-step extraction, cultivation, and characterization of adipose tissue-derived stem cells (ADSCs) from Swiss mice epididymal adipose tissue.

Mesenchymal stem cells (MSCs) have been extensively studied as a new therapeutic approach, mainly to stop exacerbated inflammation due to their potential ...

Fluorescence-Based Sorting of Adipose-Derived Extracellular Vesicles

Setting a Successful Sorting for Extracellular Vesicle Isolation

Extracellular vesicles (EVs) released by mesenchymal stromal cells (MSCs) contain a set of microRNAs with regenerative and anti-inflammatory roles. Therefore, purified MSC-EVs are envisioned as a next-generation therapeutic option for a wide array of diseases. In this protocol, we report the strategy for successfully sorting EVs from the supernatant of adipose-derived MSCs (ASCs), often used in orthopedics regenerative medicine applications.
First, we described the sample preparation, focusing on EV isolation and labeling steps with carboxyfluorescein succinimidyl ester (CFSE) for fluorescence detection; subsequently, we detailed the sorting process, which constitutes the main part of the protocol. 
In addition to the rules defined by MISEV 2023 and MIFlowCyt EV guidelines, we applied specific experimental conditions concerning nozzle size, frequency, and sheath pressure. Morphological parameters are established using beads of diameters selected to cover the theoretical range of EV size. After ASC-EVs sorting, we performed a purity check of the sorted fraction by re-analyzing it with the sorter and verifying the EV size distribution with the nanoparticle tracking analysis technique.
Due to the increasing importance of EVs, having a pure population to study and characterize is becoming crucial. Here, we demonstrate a winner strategy to set up sorting to achieve this goal.

This protocol provides a detailed description of sorting extracellular vesicles (EVs) released by mesenchymal stromal cells. In particular, it focuses on the instrument setting and the optimization of the sorting conditions. The goal is to sort extracellular vesicles while preserving their characteristics.

Extracellular vesicles (EVs) released by mesenchymal stromal cells (MSCs) contain a set of microRNAs with regenerative and anti-inflammatory roles. ...