We would like to thank Jennifer Petrosino and David DiSilvestro for editorial help. This research was supported by Award Number 20020728 from the American Egg Board and Award Number 10040042 from Novo Nordisk Pharmaceuticals as well as by the Food Innovation Center, Office for International Affairs, Center for Advanced Functional Foods Research, and Entrepreneurship at OSU as well as the National Science Foundation grant EEC-0914790 (L.J.L). The project described was supported by Award Number R21OD017244 (O.Z.) and UL1RR025755 (OSUCCC) from the National Center for Research Resources, funded by the Office of the Director, National Institutes of Health (OD) and supported by the NIH Roadmap for Medical Research and &#160;NCI P30CA16058. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.

The study protocol was approved by The Ohio State University Ethics Committees. Animal experiments were approved by IACUC protocol. All procedures were performed under the level 2 biosafety cabinet with laminar flow. We followed all standard safety requirements and procedures. The microencapsulation technique for preparation of microcapsules has been performed as described17,18.
1. Preparations of Materials
<ol>
	<li>Prepare 10 ml of 2% sodium alginate solution in autoclaved physiological saline (0.9% NaCl in water). Prepare 0.05% PLL solution in physiological saline. Prepare these solutions the day before and stir overnight. Filter the solutions with 0.22 &#956;m filter before use.</li>
	<li>Prepare 50 mM sodium citrate and 100 mM CaCl2 in 0.9% NaCl solutions and autoclave them.</li>
	<li>Autoclave all solutions, needles, electrodes, and beakers. Thoroughly clean needles with wires to avoid clogging.</li>
	<li>Determine the appropriate amount of cells to use for the capsules (102 microcapsules are needed for every cm2 of well and there are approximately 500 cells per capsule18). Use 1 ml of sodium alginate per two million cells.</li>
	<li>Prepare a &#8216;Fibroblast Growth Medium&#8217; containing 10% calf serum, and 100 U/ml penicillin/streptomycin in a high glucose (4,500 mg/l glucose) Dulbecco&#39;s Modified Eagle&#39;s medium (DMEM).
	<ol>
		<li>Prepare a &#8216;Differentiation Medium I&#8217; containing 10% fetal bovine serum, 10 &#181;g/ml insulin, 1 &#181;M dexamethasone, 0.5 mM 3-isobutyl-1-methyl xanthine, and 100 U/ml penicillin/streptomycin in DMEM.</li>
		<li>Prepare a &#8216;Differentiation Medium II&#8217; containing 10% fetal bovine serum, 10 &#181;g/ml insulin, and 100 U/ml penicillin/streptomycin in DMEM.</li>
	</ol>
	</li>
	<li>Prepare lysis buffer containing one protease inhibitor tablet per 10 ml Radio-Immunoprecipitation Assay buffer (RIPA buffer).</li>
</ol>
2. Alginate Microbeads Preparation (Figure 1A)
<ol>
	<li>Remove old medium from cell culture flask. Rinse cells with 10 ml of PBS. Bring cells in suspension with 0.25% trypsin-EDTA (2 ml per one confluent T175 flask).</li>
	<li>Count cells in cell suspension using a hemocytometer. Use 10 ml aliquot from the cell suspension and count cells according to manufacturer&#8217;s instructions. Centrifuge the remaining cells in centrifugation medium at 480 x g at room temperature for 5 min.</li>
	<li>Suspend the cell pellet in sodium alginate as described in step 1.4. Transfer the sodium alginate-cell solution to a 5 ml syringe.</li>
	<li>Remove air bubbles in the solution, add a 23-gauge needle and invert the syringe to create a 1 ml pocket of air.</li>
	<li>Place a small beaker (180 ml) containing 144 ml of 100 mM CaCl2 solution under the needle spout of the encapsulator. Attach the electrode to the encapsulator with the tip approximately 2.5 cm above the surface of the 100 mM CaCl2 solution.</li>
	<li>Place tightly the syringe containing the sodium alginate-cell solution in the syringe pump. Attach the rubber tube to the opening of the syringe. Push the plunger until the sodium alginate-cell solution enters halfway through the tube. Adjust the voltage to 5.4 kV. Set the 12.06 mm diameter on the syringe pump. Adjust the speed to 3 ml/hr. Start the pump. Turn on the encapsulator and maintain the voltage at 5.4 kV.</li>
	<li>Close the window of the hood and avoid any unnecessary vibration till the end of formation of the alginate microbeads. After all solution passes through the needle, solidify the alginate ball-shaped microbeads in the 100 mM CaCl2 solution for additional 20 min before coating with PLL.</li>
</ol>
3. Coating Microbeads with PLL (Figure 1B)
<ol>
	<li>Remove the beaker containing the sodium alginate-cell ball-shaped microbeads and transfer these microbeads into a 50 ml centrifugation tube. Remove CaCl2 solution from the microbead pellet.</li>
	<li>Wash the alginate-cell ball-shaped microbeads by adding 30 ml of 0.9% NaCl. Shake the tube by hand gently. Remove 0.9% NaCl with 25 ml pipette after the microbeads have precipitated by gravitation. Repeat two more times for a total of 3 washes.</li>
	<li>Use 10 ml of 0.05% PLL solution for every 1 ml of sodium alginate solution. Add the 0.05% PLL and vortex at 1,000 rotations per min for 10 min. 
	Note: Usually, 10 min is sufficient for PLL coating.</li>
	<li>After PLL coat is formed, remove the PLL solution and wash the capsules 3 times as described in 3.2.</li>
</ol>
4. Removal of Alginate Core (Figure 1C)
<ol>
	<li>Add 30 ml of 50 mM sodium citrate solution. Wait 5 min or until all the sodium alginate is dissolved. Wash capsules three times as described in step 3.1.1.</li>
	<li>Remove the 0.9% NaCl, add 20 ml of culture medium to the 50 ml tube and transfer all capsules containing the cells to a cell culture flask. Handle encapsulated cells under standard cell culture conditions18.</li>
</ol>
5. In Vitro Applications to Study Xenograft and Host Cell Interactions or Kinetics of Metabolite Influx/Efflux between Cells (Figure 2)
<ol>
	<li>Culture host cells on 24 well plate until confluent for co-cultures. Use the &#8216;Fibroblast Growth Medium&#8217; for culturing preadipocytes.</li>
	<li>Transfer microcapsules into 24 well plate containing confluent host cells. Add microcapsules to achieve a monolayer (102 microcapsules/cm2 of well).</li>
	<li>Induce pre-adipocyte differentiation with Differentiation Medium I. Every 48 hr, change media to Differentiation Medium II &#160;for six days. Lyse cells in RIPA buffer. Use 50 &#181;g protein per condition to analyze protein expression using Western blot.</li>
</ol>
6. In Vivo Application for Treatment of Obesity (Figure 3)
<ol>
	<li>Mix 4% isoflurane with oxygen for induction of anesthesia and 2% isoflurane with oxygen for maintenance of anesthesia. Confirm adequate anesthetic depth by toe pinch.
	<ol>
		<li>Apply anti-itch ointment on eyes to protect the corneas from drying out.</li>
	</ol>
	</li>
	<li>Use encapsulated cells that are permanently labeled with artificial fluorescence protein, such as green fluorescence protein (GFP).</li>
	<li>Use a 3 ml syringe and a 20 gauge needle to inject encapsulated cells.
	<ol>
		<li>Inject 0.5 x 106 cells suspended in 0.2 ml of PBS into each iAb fat depot that is located in the intraperitoneal area between a gonad and kidney as shown in Figure 3. Use this volume of PBS and cell number for mice with an average weight of 40 g. Adjust cell number and volume in mice that have different weight or for determination of dose-dependent effects.</li>
	</ol>
	</li>
</ol>

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No conflicts of interest declared.

Various methods have been used to encapsulate cells, including drying, extrusion, and emulsion19. In this method, the alginate beads are extruded through a needle, then coated with PLL and the alginate core will be dissolved to complete the encapsulation. Although this method has been used for years, formation of the beads with the desired size and spherical shape is still challenging. The size of the capsules is highly dependent on the viscosity of sodium alginate solution, the extruder diameter and the dista...

Increasing incidence of chronic diseases1 has stimulated studies on transplantation of therapeutic cell populations2. Syngenic or allogenic stem cells are the most commonly used cell types for these applications2. However, these treatments do not allow control of differentiation and migration of stem cells after implantation and are not cost efficient. Transplantation of genetically modified cells with beneficial functions anticipates improving the treatment of many diseases. However, genetic cell modifications are recognized by the host&#8217;s immune system, therefore, these treatments require immunosuppression3. Encapsulation of cells producing insulin has been developed by Dr. Chang4. The technique is based on encapsulation of cells in alginate droplets that are immersed into a calcium chloride solution. Alginate molecules consist of mannuronic (M) and guluronic acid (G) and can be connected by Ca2+. After gelation, the beads are suspended a poly-L-lysine (PLL) solution. During this step, PLL binds to G and M in the alginate molecules which establishes the capsule&#8217;s membrane. The porosity of the capsule&#8217;s membrane can be modulated by varying the M and PLL concentrations, the incubation time, and temperature. The binding of PLL also depends on the type and concentration of alginate. Alginate matrices crosslinked with Ca2+ ions, are unstable in the physiological environment or in common buffer solutions with high concentration of phosphate and citrate ions. These buffers can extract Ca2+ from the alginate and liquefy the core. Liquefaction of the alginate core provides space inside the capsules for cellular movement and growth. Cells encapsulated in polyanionic alginate with polycationic poly-L-lysine (APL) are impermeable for immunoglobulins but have influx of nutrients and efflux of toxins. These APL&#39;s properties enable the long term survival of encapsulated cells after transplantation into genetically different hosts. Elliott et al. reported the survival of functioning encapsulated porcine pancreatic cells in a human patient nine years after implantation5.
Encapsulation techniques can be classified into microencapsulation (3-800 &#181;m) and macroencapsulation (larger than 1,000 &#181;m). Microcapsules are more durable than macrocapsules6. Since its discovery by Dr. Chang and colleagues in 1964, microencapsulation has been widely used for the encapsulation of anabolic cells producing insulin, other hormones, and bioactive molecules7. These treatments faced several challenges in the host tissue including fibrosis and immune response8. Initially, the side effects related to the quality of biopolymers have been resolved. However, transplantation of anabolic cells still initiates side effects, such as fibrosis, as a result of hormone overproduction outside of a specialized gland.
In recent decades, obesity and type 2 diabetes has reached epidemic proportions9. More than 30% of adult people worldwide are overweight and obese10. Increased intra-abdominal (iAb) fat formation increases incidence of chronic inflammation and promotes type 2 diabetes, cardiovascular disease, certain cancers, and other morbidities11-13. Several lines of evidence suggested that pathogenesis associated with iAb fat can be averted by specific adipocytes. Recent studies have shown that transplantation of subcutaneous adipocytes into iAb region can improve metabolism and decrease obesity and insulin resistance in rodents in vivo14. Effective reduction of obesity and insulin resistance has been associated with thermogenic adipocytes capable of dissipating energy in form of heat15,16. Thermogenic modification of adipocytes can be achieved by stable transfection of genes participating in the mitochondrial proton uncoupling, such as uncoupling protein 1 (Ucp1) or of genes regulating expression of Ucp1 and other thermogenic genes15,16. Our recent studies showed that deficiency in aldehyde dehydrogenase 1 a1 (Aldh1a1) leads to the thermogenic remodeling of iAb fat that reduces obesity and insulin resistance in these mice17,18. Notably, encapsulation of thermogenic Aldh1a1 deficient (Aldh1a1-/-) preadipocytes mediates same therapeutic effect in iAb fat in obese wild type mice, suggesting new therapeutic opportunities for treatment of iAb fat18. In experimental settings, encapsulated cells enable researchers to study effects of specific cell populations in a cost effective manner19. Here we discuss the method of encapsulation of a thermogenic catabolic cell line and its laboratory and therapeutic application in a mouse model of obesity. The protocol describes three phases for microcapsule production (Figure 1): the formation of the alginate microbeads (Figure 1A), the formation of the polycationic poly-L-lysine (PLL) membranes on the surface of microbeads (Figure 1B), and the removal of the alginate cores (Figure 1C).

<table><tbody><tr><td>Encapsulation device (VAR V1)</td><td>Nisco</td><td>LIN-0042</td><td>None</td></tr><tr><td>KD scientific syringe pump</td><td>KD scientific</td><td>780100Y</td><td>None</td></tr><tr><td>Olympus microscope&amp;nbsp;</td><td>Olympus Optical</td><td>IX70-S8F2</td><td>None</td></tr><tr><td>Sodium alginate</td><td>Sigma</td><td>MKBP8122V</td><td>None</td></tr><tr><td>Poly-L-lysine hydrobromide (PLL)</td><td>Sigma</td><td>020M5006V</td><td>None</td></tr><tr><td>Calcium chloride</td><td>Sigma</td><td>SLBJ2662V</td><td>None</td></tr><tr><td>Sodium citrate tribasic dihydrate</td><td>Sigma</td><td>030M0200</td><td>None</td></tr><tr><td>Sodium chloride</td><td>Sigma</td><td>SLBD2595V</td><td>None</td></tr><tr><td>Mini-PROTEAN TGX Gels</td><td>Bio-Rad</td><td>456-1093</td><td>None</td></tr><tr><td>ATGL primary antibody (from rabbit)</td><td>Cell Signaling</td><td>2138S</td><td>None</td></tr><tr><td>Secondary anti body (anti rabbit)</td><td>LI-COR</td><td>926-68071</td><td>None</td></tr><tr><td>Radio-Immunoprecipitation Assay (RIPA) buffer</td><td>Boston BioProducts</td><td>D25Y6Z</td><td>None</td></tr><tr><td>Phosphate buffered saline (PBS)</td><td>Sigma</td><td>RNBD2893</td><td>None</td></tr><tr><td>Trypsin</td><td>Gibco</td><td>25200-056</td><td>None</td></tr><tr><td>Cortizone 10 anti-itch ointment</td><td>Cortizone 10</td><td>C4029138</td><td>None</td></tr><tr><td>Dulbecco&#039;s Modified Eagle Medium (DMEM)</td><td>Gibco</td><td>11965-092</td><td>None</td></tr><tr><td>Newborn calf serum (CS)</td><td>Sigma</td><td>N4762</td><td>None</td></tr><tr><td>Fetal bovine serum (FBS)</td><td>Sigma</td><td>F4135</td><td>None</td></tr><tr><td>3-Isobutyl-1-methylxanthine (IBMX)</td><td>Sigma</td><td>I0516</td><td>None</td></tr><tr><td>Dexamethasone</td><td>Sigma</td><td>D4902</td><td>None</td></tr><tr><td>Insulin (bovine)</td><td>Sigma</td><td>I5879</td><td>None</td></tr><tr><td>Protease inhibitor cocktail tablets</td><td>Roche</td><td>4693159001</td><td>None</td></tr></tbody></table>

encapsulation thermogenic preadipocytes for transplantation into adipose tissue depots

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular weight metabolites in tissues of the treated host to achieve long-term survival. The semipermeable membrane allows engrafted encapsulated cells to avoid rejection by the immune system. The encapsulation procedure was designed to enable a controlled release of bioactive compounds, such as insulin, other hormones, and cytokines. Here we describe a method for encapsulation of catabolic cells, which consume lipids for heat production and energy dissipation (thermogenesis) in the intra-abdominal adipose tissue of obese mice. Encapsulation of thermogenic catabolic cells may be potentially applicable to the prevention and treatment of obesity and type 2 diabetes. Another potential application of catabolic cells may include detoxification from alcohols or other toxic metabolites and environmental pollutants.

Figure 1 shows that every step of microbeads production could be controlled under the microscope. Figure 2A shows how to co-culture adipocytes with a monolayer of encapsulated cells. Figure 2B is a representative example of a quantitative study using adipocyte/microcapsules co-cultures that were described in section 5. Lysates of adipocytes were analyzed using Western blot. Encapsulated cells were not analyzed in this experiment. Primary ATGL and &#946;-actin antibodies ...

Watch this Scientific Journal Video about Encapsulation Thermogenic Preadipocytes for Transplantation into Adipose Tissue Depots at JoVE.com

Encapsulation Thermogenic Preadipocytes for Transplantation into Adipose Tissue Depots

Here, we present a protocol for encapsulation of catabolic cells, which consume lipids for heat production in intra-abdominal adipose tissue and increase energy dissipation in obese mice.

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular ...

encapsulation-thermogenic-preadipocytes-for-transplantation-into

Research

JoVE Journal

Medicine

9.3K Views.  The Ohio State University. Here, we present a protocol for encapsulation of catabolic cells, which consume lipids for heat production in intra-abdominal adipose tissue and increase energy dissipation in obese mice.

Video: Encapsulation Thermogenic Preadipocytes for Transplantation into Adipose Tissue Depots

A Microphysiologic Platform for Human Fat: Sandwiched White Adipose Tissue

White adipose tissue (WAT) plays a crucial role in regulating weight and everyday health. Still, there are significant limitations to available primary culture models, all of which have failed to faithfully recapitulate the adipose microenvironment or extend WAT viability beyond two weeks. The lack of a reliable primary culture model severely impedes research in WAT metabolism and drug development. To this end we have utilized NIH's standards of a microphysiologic system to develop a novel platform for WAT primary culture called 'SWAT' (sandwiched white adipose tissue). We overcome the natural buoyancy of adipocytes by sandwiching minced WAT clusters between sheets of adipose-derived stromal cells. In this construct, WAT samples are viable over eight weeks in culture. SWAT maintains the intact ECM, cell-to-cell contacts, and physical pressures of in vivo WAT conditions; additionally, SWAT maintains a robust transcriptional profile, sensitivity to exogenous chemical signaling, and whole tissue function. SWAT represents a simple, reproducible, and effective method of primary adipose culture. Potentially, it is a broadly applicable platform for research in WAT physiology, pathophysiology, metabolism, and pharmaceutical development.

White adipose tissue (WAT) has critical deficiencies in its current primary culture models, hindering pharmacological development and metabolic studies. Here, we present a protocol to produce an adipose microphysiological system by sandwiching WAT between sheets of stromal cells. This construct provides a stable and adaptable platform for primary WAT culture.

White adipose tissue (WAT) plays a crucial role in regulating weight and everyday health.  Still, there are significant limitations to available primary ...

Behavior

Isolation, Expansion, and Adipogenic Induction of CD34+CD31+ Endothelial Cells from Human Omental and Subcutaneous Adipose Tissue

Obesity is accompanied by an extensive remodeling of adipose tissue primarily via adipocyte hypertrophy. Extreme adipocyte growth results in a poor response to insulin, local hypoxia, and inflammation. By stimulating the differentiation of functional white adipocytes from progenitors, radical hypertrophy of the adipocyte population can be prevented and, consequently, the metabolic health of adipose tissue can be improved along with a reduction of inflammation. Also, by stimulating a differentiation of beige/brown adipocytes, the total body energy expenditure can be increased, resulting in weight loss. This approach could prevent the development of obesity co-morbidities such as type 2 diabetes and cardiovascular disease.
This paper describes the isolation, expansion, and differentiation of white and beige adipocytes from a subset of human adipose tissue endothelial cells that co-express the CD31 and CD34 markers. The method is relatively cheap and is not labor-intensive. It requires access to human adipose tissue and the subcutaneous depot is suitable for sampling. For this protocol, fresh adipose tissue samples from morbidly obese subjects [body mass index (BMI) &#62;35] are collected during bariatric surgery procedures. Using a sequential immunoseparation from the stromal vascular fraction, enough cells are produced from as little as 2&#8211;3 g of fat. These cells can be expanded in culture over 10&#8211;14 days, can be cryopreserved, and retain their adipogenic properties with passaging up to passage 5&#8211;6. The cells are treated for 14 days with an adipogenic cocktail using a combination of human insulin and the PPAR&#947; agonist-rosiglitazone.
This methodology can be used for obtaining proof of concept experiments on molecular mechanisms that drive adipogenic responses in adipose endothelial cells, or for screening new drugs that can enhance the adipogenic response directed either towards white or beige/brown adipocyte differentiation. Using small subcutaneous biopsies, this methodology can be used to screen out non-responder subjects for clinical trials aimed to stimulate beige/brown and white adipocytes for the treatment of obesity and co-morbidities.

The differentiation of white and beige adipocytes from adipose tissue vascular progenitors bears potential for metabolic improvement in obesity. We describe protocols for a CD34+CD31+ endothelial cell isolation from human fat and for a subsequent in vitro expansion and differentiation into white and beige adipocytes. Several downstream applications are discussed.

Obesity is accompanied by an extensive remodeling of adipose tissue primarily via adipocyte hypertrophy. Extreme adipocyte growth results in a poor ...

Immunology and Infection

Isolation and Differentiation of Stromal Vascular Cells to Beige/Brite Cells

Brown adipocytes have the ability to uncouple the respiratory chain in mitochondria and dissipate chemical energy as heat. Development of UCP1-positive brown adipocytes in white adipose tissues (so called beige or brite cells) is highly induced by a variety of environmental cues such as chronic cold exposure or by PPAR&gamma; agonists, therefore, this cell type has potential as a therapeutic target for obesity treatment. Although most immortalized adipocyte lines cannot recapitulate the process of "browning" of white fat in culture, primary adipocytes isolated from stromal vascular fraction in subcutaneous white adipose tissue (WAT) provide a reliable cellular system to study the molecular control of beige/brite cell development. Here we describe a protocol for effective isolation of primary preadipocytes and for inducing differentiation to beige/brite cells in culture. The browning effect can be assessed by the expression of brown fat-selective markers such as UCP1.

Primary white preadipocytes isolated from white adipose tissues in mice can be differentiated into beige/brite cells. Presented here is a reliable cellular model system to study the molecular regulation of "browning" of white fat.

Brown adipocytes have the ability to uncouple the  respiratory chain in mitochondria and dissipate chemical energy as heat.  Development of UCP1-positive ...

Biology

Three-Dimensional Culture of Vascularized Thermogenic Adipose Tissue from Microvascular Fragments

Engineering thermogenic adipose tissue (e.g., beige or brown adipose tissues) has been investigated as a potential therapy for metabolic diseases or for the design of personalized microtissues for health screening and drug testing. Current strategies are often quite complex and fail to accurately fully depict the multicellular and functional properties of thermogenic adipose tissue. Microvascular fragments, small intact microvessels comprised of arteriole, venules, and capillaries isolated from adipose tissue, serve as a single autologous source of cells that enable vascularization and adipose tissue formation. This article describes methods for optimizing culture conditions to enable the generation of three-dimensional, vascularized, and functional thermogenic adipose tissues from microvascular fragments, including protocols for isolating microvascular fragments from adipose tissue and culture conditions. Additionally, best practices are discussed, as are techniques for characterizing the engineered tissues, and sample results from both rodent and human microvascular fragments are provided. This approach has the potential to be utilized for the understanding and development of treatments for obesity and metabolic disease.

Here, we present a detailed protocol outlining the use of microvascular fragments isolated from rodent or human fat tissue as a straightforward approach to engineer functional, vascularized beige adipose tissue.

Engineering thermogenic adipose tissue (e.g., beige or brown adipose tissues) has been investigated as a potential therapy for metabolic diseases or for ...

Bioengineering

Fat-Covered Islet Transplantation Using Epididymal White Adipose Tissue

Islet transplantation is a cellular replacement therapy for severe diabetes mellitus. The intraperitoneal cavity is typically the transplant site for this procedure. However, intraperitoneal islet transplantation has some limitations, including poor transplant efficacy, difficult graft detection ability, and a lack of graftectomy capability for post-transplant analysis. In this paper, "fat-covered islet transplantation", an intraperitoneal islet transplantation method that utilizes epididymal white adipose tissue, is used to assess the therapeutic effects of bioengineered islets. The simplicity of the method lies in the seeding of islets onto epididymal white adipose tissue and using the tissue to cover the islets. While this method can be categorized as an intraperitoneal islet transplantation technique, it shares characteristics with intra-adipose tissue islet transplantation. The fat-covered islet transplantation method demonstrates more robust therapeutic effects than intra-adipose tissue islet transplantation, however, including the improvement of blood glucose and plasma insulin levels and the potential for graft removal. We recommend the adoption of this method for assessing the mechanisms of islet engraftment into white adipose tissue and the therapeutic effects of bioengineered islets.

This fat-covered islet transplantation method is suitable for the detection of engrafted islets in the intraperitoneal cavity. Notably, it does not require the use of biobinding agents or suturing.

Islet transplantation is a cellular replacement therapy for severe diabetes mellitus. The intraperitoneal cavity is typically the transplant site for this ...

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. ...

Preparation of Adipose Progenitor Cells from Mouse Epididymal Adipose Tissues

Obesity and metabolic disorders such as diabetes, heart disease, and cancer, are all associated with dramatic adipose tissue remodeling. Tissue-resident adipose progenitor cells (APCs) play a key role in adipose tissue homeostasis and can contribute to the tissue pathology. The growing use of single cell analysis technologies &#8211; including single-cell RNA-sequencing and single-cell proteomics &#8211; is transforming the stem/progenitor cell field by permitting unprecedented resolution of individual cell expression changes within the context of population- or tissue-wide changes. In this article, we provide detailed protocols to dissect mouse epididymal adipose tissue, isolate single adipose tissue-derived cells, and perform fluorescence activated cell sorting (FACS) to enrich for viable Sca1+/CD31-/CD45-/Ter119- APCs. These protocols will allow investigators to prepare high quality APCs suitable for downstream analyses such as single cell RNA sequencing.

We present a simple method to isolate highly viable adipose progenitor cells from mouse epididymal fat pads using fluorescence activated cell sorting.

Obesity and metabolic disorders such as diabetes, heart disease, and cancer, are all associated with dramatic adipose tissue remodeling. Tissue-resident ...

Human SATMVECs: Isolation and Adipocyte Cross-Talk Studies

Studying Adipose Endothelial Cell/Adipocyte Cross-Talk in Human Subcutaneous Adipose Tissue

Microvascular endothelial cells (MVECs) have many critical roles, including control of vascular tone, regulation of thrombosis, and angiogenesis. Significant heterogeneity in endothelial cell (EC) genotype and phenotype depends on their vascular bed and host disease state. The ability to isolate MVECs from tissue-specific vascular beds and individual patient groups offers the opportunity to directly compare MVEC function in different disease states. Here, using subcutaneous adipose tissue (SAT) taken at the time of insertion of cardiac implantable electronic devices (CIED), we describe a method for the isolation of a pure population of functional human subcutaneous adipose tissue MVEC (hSATMVEC) and an experimental model of hSATMVEC-adipocyte cross-talk.
hSATMVEC were isolated following enzymatic digestion of SAT by incubation with anti-CD31 antibody-coated magnetic beads and passage through magnetic columns. hSATMVEC were grown and passaged on gelatin-coated plates. Experiments used cells at passages 2-4. Cells maintained classic features of EC morphology until at least passage 5. Flow cytometric assessment showed 99.5% purity of isolated hSATMVEC, defined as CD31+/CD144+/CD45-. Isolated hSATMVEC from controls had a population doubling time of approximately 57 h, and active proliferation was confirmed using a cell proliferation imaging kit. Isolated hSATMVEC function was assessed using their response to insulin stimulation and angiogenic tube-forming potential. We then established an hSATMVEC-subcutaneous adipocyte co-culture model to study cellular cross-talk and demonstrated a downstream effect of hSATMVEC on adipocyte function.
hSATMVEC can be isolated from SAT taken at the time of CIED insertion and are of sufficient purity to both experimentally phenotype and study hSATMVEC-adipocyte cross-talk.

Author Spotlight: Insights into Cardiometabolic Diseases with Subcutaneous Adipose Tissue Microvasculature Studies 

Here, we describe a protocol for isolating, culturing, and phenotyping microvascular endothelial cells from human subcutaneous adipose tissue (hSATMVECs). Additionally, we describe an experimental model of hSATMVEC-adipocyte cross-talk.

Microvascular endothelial cells (MVECs) have many critical roles, including control of vascular tone, regulation of thrombosis, and angiogenesis. ...

Isolation and Differentiation of Primary White and Brown Preadipocytes from Newborn Mice

The understanding of the mechanisms underlying adipocyte differentiation and function has greatly benefited from the use of immortalized white preadipocyte cell lines. These cultured cell lines, however, have limitations. They do not fully capture the diverse functional spectrum of the heterogenous adipocyte populations that are now known to exist within white adipose depots. To provide a more physiologically relevant model to study the complexity of white adipose tissue, a protocol has been developed and optimized to enable simultaneous isolation of primary white and brown adipocyte progenitors from newborn mice, their rapid expansion in culture, and their differentiation in vitro into mature, fully functional adipocytes. The primary advantage of isolating primary cells from newborn, rather than adult mice, is that the adipose depots are actively developing and are, therefore, a rich source of proliferating preadipocytes. Primary preadipocytes isolated using this protocol differentiate rapidly upon reaching confluence and become fully mature in 4-5 days, a temporal window that accurately reflects the appearance of developed fat pads in newborn mice. Primary cultures prepared using this strategy can be expanded and studied with high reproducibility, making them suitable for genetic and phenotypic screens and enabling the study of the cell-autonomous adipocyte phenotypes of genetic mouse models. This protocol offers a simple, rapid, and inexpensive approach to study the complexity of adipose tissue in vitro.

This report describes a protocol for the simultaneous isolation of primary brown and white preadipocytes from newborn mice. Isolated cells can be grown in culture and induced to differentiate into fully mature white and brown adipocytes. The method enables genetic, molecular, and functional characterization of primary fat cells in culture.

The understanding of the mechanisms underlying adipocyte differentiation and function has greatly benefited from the use of immortalized white ...

Differentiation and Imaging of Brown Adipocytes from the Stromal Vascular Fraction of Interscapular Adipose Tissue from Newborn Mice

Brown adipose tissue (BAT) is only present in mammals and has a thermogenic function. Brown adipocytes are characterized by a multilocular cytoplasm with multiple lipid droplets, a central nucleus, a high mitochondrial content, and the expression of uncoupling protein 1 (UCP1). BAT has been proposed as a potential therapeutic target for obesity and its associated metabolic disorders due to its ability to dissipate metabolic energy as heat. To investigate BAT function and regulation, brown adipocyte culturing is indispensable. The present protocol optimizes tissue processing and cell differentiation for culturing brown adipocytes from newborn mice. Additionally, procedures for the imaging of differentiated adipocytes with both confocal immunofluorescence and transmission electron microscopy are shown. In the brown adipocytes differentiated with the techniques described herein, the major defining features of classical BAT are preserved, including high UCP1 levels, increased mitochondrial mass, and very close physical contact between the lipid droplets and mitochondria, making this method a valuable tool for BAT studies.

Preadipocytes are isolated from the stromal vascular fraction of interscapular brown adipose tissue from newborn mice and differentiated into cells that accumulate lipid droplets, express molecular markers, and show the mitochondrial morphology of mature brown adipocytes. These cells are further analyzed by immunofluorescence and transmission electron microscopy.

Brown adipose tissue (BAT) is only present in mammals and has a thermogenic function. Brown adipocytes are characterized by a multilocular cytoplasm with ...