This study was funded by a Grant-in-Aid for Scientific Research (C) (19K09839, NS) from the Ministry of Education, Culture, Sports, Science and Technology of Japan.

The following procedure is performed in three steps. The first step includes the induction of diabetes in the recipient mice and the isolation of donor islets. The second step involves the preparation of islets before transplantation. In the third step, islet transplantation onto epididymal adipose tissue and covering of the islets using the adipose tissue is performed. After that, the therapeutic effects were assessed. The handling of the mice and the experimental procedures performed in this study comply with the &#39;&#39;Principles of Laboratory Animal Care&#39;&#39; (Guide for the Care and Use of Laboratory Animals, National Institutes of Health publication 8th&#160;edition, 2011), and the experimental protocol was approved by the Animal Care and Use Committee of Fukuoka University (approval number: 186018).
1. Surgical preparation
<ol>
	<li>Induction of diabetes: Induce diabetes in 20-25 g body weight, 8-12-week-old recipient male mice through intravenous injection of 18 mg/mL streptozotocin solution prepared in 0.1M citrate buffer (180 mg/kg body weight). Mice with blood glucose levels exceeding 400 mg/dL are considered to be diabetic. Use diabetic mice within 1 week after diabetes induction before excessive atrophy of the epididymal white adipose tissue for covering islets.</li>
	<li>Islet isolation: Perform murine islet isolation one day before transplantation following Gotoh&#39;s method27 for islet isolation.</li>
	<li>In brief, digest pancreatic tissue using collagenase solution. Isolate islets by density gradient centrifugation using an appropriate cell separation solution. Then culture islets overnight in an incubator at 22 &#176;C and 5% CO2 (culture at &#60;37 &#176;C has been reported to prevent islet death28,29,30,31). 
	NOTE:&#160;Handle the purified islet cultures in a safety cabinet. Filter-sterilize all solutions used for islet isolation and culture using a 0.22 &#181;m filter.</li>
</ol>
2. Preparation of islets for transplantation
<ol>
	<li>Gather the appropriate instruments and materials as indicated in Figure 1A.</li>
	<li>As digestive enzymes such as amylase and lipase may result in injury to the isolated and transplanted islets and a loss of islets can occur from being trapped in contaminating fibrous tissues within the culture dish, prior to transplantation, use forceps to handpick any extra-islet components from the pancreas, including acinar and fibrous tissues (Figure 1B), under a dissecting microscope. After picking, use a cell strainer to filter out single acinar cells.</li>
	<li>Transfer the filtered islets to a new culture dish containing any appropriate culture medium or buffer solution (e.g., DMEM with low glucose, RPMI1640, CMRL1066, or HBSS) supplemented with bovine serum or albumin to prevent islet attachment to plastic and swirl the dish to position the islets in the center of the dish (Figure 1C). Using a P200 micropipette and the microscope, pick the individual islets into an appropriate collection tube (Figure 1D).</li>
	<li>Place a new, 40 &#956;m cell strainer on top of a 50 mL plastic tube (Figure 1E left and center) and wash the filter with fresh medium (Figure 1E right).</li>
	<li>Use a 1000 &#956;L pipette to add the islets to the strainer to separate the islets and single acinar cells (Figure 1F1 and Figure 1F2). 
	NOTE: The purified islets on cell strainer will be approximately 100% pure.</li>
	<li>Use forceps to invert the strainer on a new 60- or 100-mm sized non-treated culture dish containing culture medium or an appropriate buffer solution supplemented with bovine serum or albumin (Figure 1F3 and Figure 1F4). Use fresh medium/buffer to flush the islets into a new culture dish. Then add enough medium/buffer to the culture dish to reach a total volume of approximately 20 mL.</li>
	<li>Count the islets under a microscope and divide the number of islets equally between individual 1.5 mL plastic centrifuge tubes according to the number of donor animals (Figure 1G). For example, two hundred, 100-200 &#181;m islet equivalents (IEQ) from two mice would be added to each of two tubes.</li>
	<li>Centrifuge the islets at 2,100 x g within&#160;1 minute at room temperature and discard the supernatant. Around 20-30 &#181;L of residual solution will typically remain in the tube (Figure 1H).</li>
</ol>
3. Islet transplantation onto epididymal adipose tissue and covering with epididymal white adipose tissue
<ol>
	<li>Before the surgery, collect an anesthesia machine for small animals, stereo microscope, light source, 50-200 &#181;L micropipette with 200 &#181;L micropipette tips, cotton swabs, a 4-0 suturing set, and disinfected surgical instruments (Figure 2A). Autoclave the cooper scissors, ophthalmic scissors, Pean forceps, tweezers, and needle holders. After autoclaving, immerse the equipment&#160;in a 1% povidone-iodine solution&#160;(Figure 2A). Use cotton swabs for mobilization of the epididymal white adipose tissue and for hemostasis in cases of bleeding. Use a micropipette with a 50-200 &#181;L tips for islet transplantation.</li>
	<li>Deliver anesthesia to the diabetic recipient mouse using an inhaled anesthetic agent (2% isoflurane in oxygen). Apply ophthalmic lubricant to both eyes to prevent drying. Then place the mouse in the supine position (Figure 2B left) and remove the hair from the abdomen to prevent infection using hair clippers and/or depilatory cream.&#160;Disinfect the abdomen and the inguinal region using at least three alternating rounds of a povidone-iodine solution followed by 70% ethanol&#160;(Figure 2B right). Before the surgery, confirm anesthesia depth via the absence of a toe pinch reflex. Provide intra-operative thermal support using a heating pad and use a&#160;surgical drape to secure the sterile surgical area.</li>
	<li>Incise the skin at the lower median area (Figure 2C left). A skin incision that is approximately 2 cm in length is recommended. Clamp the left abdominal wall with the Pean forceps (atraumatic forceps or retractor can also be used) and pull the tissue to the left side of the mouse to secure the surgical field (Figure 2C right). After laparotomy, decrease the percentage of isoflurane to 1.0-1.5% for anesthesia maintenance.</li>
	<li>Use a cotton swab to mobilize the small and large intestine to the right side of the mouse (i.e., left side of the operator). The left epididymal white adipose tissue in the abdominal cavity are located in the left inguinal area. Mobilize the epididymal white adipose tissue and the left testis to outside of the abdomen (Figure 2D left) and stretch out the tissue (2D right).</li>
	<li>Use a P200 micropipette equipped with a 200 &#181;L pipette tip to collect the entire volume of islets from one 1.5 mL tube with gentle pipetting (Figure 2E left), taking care that no islets are left in the tube upon collection. Allow the collected islets to settle to the tip of the pipette by gravity (Figure 2E right).</li>
	<li>Place the micropipette tip lightly onto the distended adipose tissue. Taking care to prevent excessive flushing of the medium/buffer in the tip, carefully seed the islets onto the tissue (Figure 2F left). After seeding, confirm a correct placement of the islets under a dissecting microscope (Figure 2F right).</li>
	<li>Cover the islets with the epididymal white adipose tissue (Figure 2G). The use of sutures or biobinding agents is not needed.</li>
	<li>Place the left testis under the epididymal white adipose tissue and return the tissues to the intraperitoneal cavity (Figure 2H). Close the skin in two layers (peritoneum, then muscle and skin) using a 4-0 suture (any sutures such as nylon&#160;or absorbable sutures can be used) (Figure 2I). Inject&#160;acetylsalicylic acid (300 mg/kg; SQ)&#160;near the wound for postoperative analgesia.&#160;Then place the mouse under a heat lamp and&#160;monitor until full recovery.</li>
</ol>
4. Monitoring after Islet transplantation (Summary)
<ol>
	<li>Assess the therapeutic effects of islet transplantation by monitoring blood glucose, glucose tolerance test and histological assessment at postoperative day (POD) 28.
	<ol>
		<li>Monitor the blood glucose, including the measurements of blood glucose at glucose tolerance test, using a small glucose meter.</li>
		<li>Collect the blood samples (a little microliters) from tail vein. Regarding histological assessment, murine insulin (for detecting engrafted islets) and von Willebrand factor (for detection of vessels, which is an evidence for islet engraftment) were detected in transplanted islets in the recovered epididymal adipose tissue by immunohistochemistry.</li>
	</ol>
	</li>
</ol>

<ol>
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We have no conflict of interests.

The fat-covered islet transplantation method incorporates techniques from two different transplant techniques: intraperitoneal islet transplantation and intra-adipose tissue islet transplantation. As the surface membrane of epididymal white adipose tissue is considered to be the white adipose tissue that is covered by the peritoneum and that is attached to the epididymis, the fat-covered islet transplantation method can be anatomically categorized as a type of intraperitoneal islet transplantation. The technique by which...

Islet transplantation is a cellular replacement therapy for patients with severe diabetes mellitus. Recent reports have shown that rates of insulin-independence at three years after transplantation improve up to 44%1 and that approximately 80% of recipients who receive more than 600,000 total islet equivalents achieve insulin independence2. Furthermore, in the most recent Collaborative Islet Transplant Registry report, it was revealed that fasting blood glucose levels were maintained at 60-140 mg/dL for over a period of 5 years in over 70% of patients who underwent islet transplant alone. The study also determined that around 90% of the patients who received islet transplant alone or islet transplantation after kidney transplant did not develop any severe hypoglycemic events for over 5 years3.
Although the clinical outcomes of this treatment have been improving, some limitations must still be addressed, including the necessity of establishing an optimal transplant site. The liver is a typical transplant site for clinical islet transplantation because it is the largest organ that can accommodate a high volume of islets. However, in some patients the liver is unavailable (e.g., due to portal hypertension, hepatitis, and/or cirrhosis4) and therefore other sites, including the renal subcapsular space5,6, omental pouch7,8,9,10, mesentery11, gastrointestinal tract12, skeletal muscle13, subcutaneous tissue13, bone marrow14, and spleen15,16,17, have been considered as alternative transplant sites.
Although intraperitoneal islet transplantation can be performed easily under local anesthesia, making the intraperitoneal cavity an appealing site for clinical islet transplantation, upon transplant, the islets are dispersed throughout the entire intraperitoneal cavity, making islet engraftment detection and successful engraftment confirmation difficult. Therefore, the intraperitoneal cavity is not widely recognized as an ideal clinical transplant site. Instead, it is frequently utilized as a control model for preclinical studies to investigate the effectiveness of transplanted encapsulated18 and bioengineered islets19. However, an exact comparison between bioengineered and control islets is difficult to achieve due to the challenges in performing an accurate engraftment assessment.
In contrast, the use of intraperitoneal white adipose tissue in the omental pouch8, mesentery, and other extrahepatic locations has been well reported10,20,21,22,23 and many of the studies investigating the function of bioengineered islets transplanted using white adipose tissue were able to report promising therapeutic outcomes20,24,25,26. As the use of epididymal adipose tissue facilitates the detection of transplanted islets, the &#34;fat-covered islet transplantation method&#34;, utilizing epididymal adipose tissue, was developed to overcome the limitations of intraperitoneal islet transplantation. In this paper, fat-covered islet transplantation using epididymal adipose tissue is described.

<table><tbody><tr><td>4-0 Nylon</td><td>Alfresa</td><td>ER2004NA45-KF2</td><td>Closing abdomen</td></tr><tr><td>Alexa 488-conjugated donkey anti-guinea pig</td><td>Jackson Immunoresearch</td><td>706-546-148</td><td>Secondary antibody for insulin antibody</td></tr><tr><td>Alexa 647-conjugated donkey anti-rabbit</td><td>Jackson Immunoresearch</td><td>711-606-152</td><td>Secondary antibody for von Willebrand factor antibody</td></tr><tr><td>DMEM, low glucose, pyruvate</td><td>ThermoFisher Scientific</td><td>11885084</td><td>Culturing islets, transplanting islets</td></tr><tr><td>Eosin</td><td>Fujifilm Wako Chemicals</td><td>051-06515</td><td>Using for staining tissue by eosin</td></tr><tr><td>Eppendorf Safe-Lock Tubes, 1.5 mL</td><td>Eppendorf</td><td>30120086</td><td>Collecting islets&amp;nbsp;</td></tr><tr><td>Falcon 15 mL Conical Centrifuge Tubes</td><td>Corning</td><td>352095</td><td>Collecting islets</td></tr><tr><td>Falcon 40 &amp;micro;m Cell Strainer</td><td>Falcon</td><td>352340</td><td>Using for separating islets from other pancreatic tissue</td></tr><tr><td>Falcon 50 mL Conical Centrifuge Tubes</td><td>Corning</td><td>352070</td><td>Discarding excessive medium/buffer</td></tr><tr><td>Guinea pig anti-insulin</td><td>Agilent Technologies Japan, Ltd. (Dako)</td><td>IR002</td><td>Primary antibody for murine insulin</td></tr><tr><td>Hematoxylin</td><td>Muto Pure Chemicals Co., Ltd.</td><td>30002</td><td>Using for staining tissue by hematoxylin</td></tr><tr><td>Isodine solution 10%</td><td>Shionogi&amp;amp;Co., Ltd.</td><td>no catalog number</td><td>Using for disinfection</td></tr><tr><td>Isoflurane</td><td>Fujifilm Wako Chemicals</td><td>095-06573</td><td>Using for anesthesia</td></tr><tr><td>Labcon 1000 &amp;micro;L ZapSilk Low Retention Pipette Tips</td><td>Labcon</td><td>1177-965-008</td><td>Using for separating islets from other pancreatic tissue</td></tr><tr><td>Labcon 200 &amp;micro;L ZapSilk Low Retention Pipette Tips</td><td>Labcon</td><td>1179-965-008</td><td>Using for seeding islets onto epididymal white adipose tissue</td></tr><tr><td>Mintsensor</td><td>Sanwa Kagaku Kenkyusho Co. Ltd.,</td><td>8AEB02E</td><td>Using for monitoring blood glucose</td></tr><tr><td>Pipetteman P-1000</td><td>Gilson</td><td>F123602</td><td>Using for separating islets from other pancreatic tissue</td></tr><tr><td>Pipetteman P-200</td><td>Gilson</td><td>F123601</td><td>Using for seeding islets onto epididymal white adipose tissue</td></tr><tr><td>Rabbit anti-vWF</td><td>Abcam</td><td>ab6994</td><td>Primary antibody for murine von Willebrand factor</td></tr></tbody></table>

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.

To compare the transplant efficacy of fat-covered islet transplantation to that after intraperitoneal islet transplantation, the same number of islets was implanted onto the peritoneum at the left paracolic space of control recipient diabetic animals. The blood glucose levels of mice with fat-covered islet transplantation were observed to gradually and significantly decrease compared to intraperitoneal islet transplanted mice (p = 0.0023; Figure 3A). One month after transplantation, the bloo...

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Fat-Covered Islet Transplantation Using Epididymal White Adipose Tissue

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 ...

fat-covered-islet-transplantation-using-epididymal-white-adipose

Research

JoVE Journal

Medicine

2.0K Views.  Fukuoka University. Dit protocol maakt het mogelijk om het mechanisme van eilandjestransplantatie in wit vetweefsel te beoordelen. Het belangrijkste voordeel van deze met vet bedekte eilandjestransplantatiemethode is dat het technisch eenvoudig te repliceren is. De methode kan worden toegepast op andere ziektemodellen.Het kan bijvoorbeeld worden gebruikt om een muismodel van kanker te maken. De procedure wordt gedemonstreerd door Naoaki Sakata, universitair hoofddocent aan de Universiteit van Fukuoka. Geb...

Video: Fat-Covered Islet Transplantation Using Epididymal White Adipose Tissue

A Method for Murine Islet Isolation and Subcapsular Kidney Transplantation

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize their blood glucose levels, islet transplantation has been proposed to be a potential treatment for type 1 diabetes 1,2. More recently, advances in human islet transplantation have further strengthened this view 1,3. However, two major limitations prevent islet transplantation from being a widespread clinical reality: (a) the requirement for large numbers of islets per patient, which severely reduces the number of potential recipients, and (b) the need for heavy immunosuppression, which significantly affects the pediatric population of patients due to their vulnerability to long-term immunosuppression. Strategies that can overcome these limitations have the potential to enhance the therapeutic utility of islet transplantation.
Islet transplantation under the mouse kidney capsule is a widely accepted model to investigate various strategies to improve islet transplantation. This experiment requires the isolation of high quality islets and implantation of islets to the diabetic recipients. Both procedures require surgical steps that can be better demonstrated by video than by text. Here, we document the detailed steps for these procedures by both video and written protocol. We also briefly discuss different transplantation models: syngeneic, allogeneic, syngeneic autoimmune, and allogeneic autoimmune.

Transplantation of isolated islets has been proposed to be a potential treatment for type 1 diabetes. Here we describe a method to isolate islets from mouse pancreata and transplant them to the subcapsular space of the kidney.

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize ...

Rat Mammary Epithelial Cell Transplantation into the Interscapular White Fat Pad

As early as the 1970s, researchers have successfully transplanted mammary epithelial cells into the interscapular white fat pad of rats. Grafting mammary epithelium using transplantation techniques takes advantage of the hormonal environment provided by the adolescent rodent host. These studies are ideally suited to explore the impact of various biological manipulations on mammary gland development and dissect many aspects of mammary gland biology. A common, but limiting, feature is that transplanted epithelial cells are strongly influenced by the surrounding stroma and outcompeted by endogenous epithelium; to utilize native mammary tissue, the abdominal-inguinal white fat pad must be cleared to remove host mammary epithelium prior to the transplantation. A major obstacle when using the rat model organism is that clearing the developing mammary tree in post-weaned rats is not efficient. When transplanted into gland-free fat pads, donor epithelial cells can repopulate the cleared host fat pad and form a functional mammary gland. The interscapular fat pad is an alternative location for these grafts. A major advantage is that it lacks ductal structures yet provides the normal stroma that is necessary to promote epithelial outgrowth and is easily accessible in the rat. Another major advantage of this technique is that it is minimally invasive, because it eliminates the need to cauterize and remove the growing endogenous mammary tree. Additionally, the interscapular fat pad contains a medial blood vessel that can be used to separate sites for grafting. Because the endogenous glands remain intact, this technique can also be used for studies comparing the endogenous mammary gland to the transplanted gland. This paper describes the method of mammary epithelial cell transplantation into the interscapular white fat pad of rats.

This article describes a transplantation method to graft donor rat mammary epithelial cells into the interscapular white fat pad of recipient animals. This method can be used to examine host and/or donor effects on mammary epithelium development and eliminates the need for pre-clearing, thereby extending the usefulness of this technique.

As early as the 1970s, researchers have successfully transplanted mammary epithelial cells into the interscapular white fat pad of rats. Grafting mammary ...

Cancer Research

Scaffold-supported Transplantation of Islets in the Epididymal Fat Pad of Diabetic Mice

Islet transplantation has been clinically proven to be effective at treating type 1 diabetes. However, the current intrahepatic transplantation strategy may incur acute whole blood reactions and result in poor islet engraftment. Here, we report a robust protocol for the transplantation of islets at the extrahepatic transplantation site-the epididymal fat pad (EFP)-in a diabetic mouse model. A protocol to isolate and purify islets at high yields from C57BL/6J mice is described, as well as a transplantation method performed by seeding islets onto a decellularized scaffold (DCS) and implanting them at the EFP site in syngeneic C57BL/6J mice rendered diabetic by streptozotocin. The DCS graft containing 500 islets reversed the hyperglycemic condition within 10 days, while the free islets without DCS required at least 30 days. The normoglycemia was maintained for up to 3 months until the graft was explanted. In conclusion, DCS enhanced the engraftment of islets into the extrahepatic site of the EFP, which could easily be retrieved and might provide a reproducible and useful platform for investigating the scaffold materials, as well as other transplantation parameters required for a successful islet engraftment.

This protocol demonstrates murine islet isolation and seeding onto a decellularized scaffold. Scaffold-supported islets were transplanted into the epididymal fat pad of streptozotocin (STZ)-induced diabetic mice. Islets survived at the transplantation site and reversed the hyperglycemic condition.

Islet transplantation has been clinically proven to be effective at treating type 1 diabetes. However, the current intrahepatic transplantation strategy ...

Bioengineering

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.

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 ...

Intra-Omental Islet Transplantation Using h-Omental Matrix Islet filliNG (hOMING)

Regenerative medicine based on cell therapy represents a new hope for curing disease. Current obstacles include proper in vivo validation of the efficiency of the therapy. For transfer to the recipient body, cells often need to be combined with biomaterials, especially hydrogels. However, validation of the efficacy of such a graft requires the right environment, the right hydrogel, and the right recipient site. The omentum might be such a site. Based on the example of islet transplantation, we developed the hOMING (h-Omental Matrix Islet filliNG) technique, which consists of the injection of the graft inside the tissue, in between the omental layers, to improve islet implantation and survival. To achieve this, islets have to be embedded in a hydrogel with a viscosity that enables its injection using an atraumatic needle. Syringes are loaded with a combination of hydrogel and islets. Several injections are performed inside the omental tissue at different entry points, and the deposition of the islet/hydrogel mixture is made along a line. We tested the feasibility of this innovative approach using dextran beads. The beads were well spread throughout the omental tissue, in close proximity to blood vessels. To test the efficacy of the graft, we transplanted islets into diabetic rats and perform a metabolic follow-up over two months. The transplanted islets exhibited a high rate of re-vascularization around and inside islets, and reversed diabetes. The hOMING technique could be applicable for other types of hydrogel or cell therapy, for cells with high metabolic activity.

Intra-Omental Islet Transplantation Using h-Omental Matrix Islet filliNG hOMING

Here, we present a protocol for in vivo validation of hydrogel-based cell therapy, illustrated by the example of islet transplantation. h-Omental Matrix Islet filliNG (hOMING) implantation allows implantation of a cell-hydrogel mixture between the omental layers, near to blood vessels, to maximize engraftment in a proper metabolic environment.

Regenerative medicine based on cell therapy represents a new hope for curing disease. Current obstacles include proper in vivo validation of the ...

Creation and Transplantation of an Adipose-derived Stem Cell (ASC) Sheet in a Diabetic Wound-healing Model

Artificial skin has achieved considerable therapeutic results in clinical practice. However, artificial skin treatments for wounds in diabetic patients with impeded blood flow or with large wounds might be prolonged. Cell-based therapies have appeared as a new technique for the treatment of diabetic ulcers, and cell-sheet engineering has improved the efficacy of cell transplantation. A number of reports have suggested that adipose-derived stem cells (ASCs), a type of mesenchymal stromal cell (MSC), exhibit therapeutic potential due to their relative abundance in adipose tissue and their accessibility for collection when compared to MSCs from other tissues. Therefore, ASCs appear to be a good source of stem cells for therapeutic use. In this study, ASC sheets from the epididymal adipose fat of normal Lewis rats were successfully created using temperature-responsive culture dishes and normal culture medium containing ascorbic acid. The ASC sheets were transplanted into Zucker diabetic fatty (ZDF) rats, a rat model of type 2 diabetes and obesity, that exhibit diminished wound healing. A wound was created on the posterior cranial surface, ASC sheets were transplanted into the wound, and a bilayer artificial skin was used to cover the sheets. ZDF rats that received ASC sheets had better wound healing than ZDF rats without the transplantation of ASC sheets. This approach was limited because ASC sheets are sensitive to dry conditions, requiring the maintenance of a moist wound environment. Therefore, artificial skin was used to cover the ASC sheet to prevent drying. The allogenic transplantation of ASC sheets in combination with artificial skin might also be applicable to other intractable ulcers or burns, such as those observed with peripheral arterial disease and collagen disease, and might be administered to patients who are undernourished or are using steroids. Thus, this treatment might be the first step towards improving the therapeutic options for diabetic wound healing.

Creation and Transplantation of an Adipose-derived Stem Cell ASC Sheet in a Diabetic Wound-healing Model

Adipose-derived stem cells (ASCs) are easily isolated and harvested from the fat of normal rats. ASC sheets can be created using cell-sheet engineering and can be transplanted into Zucker diabetic fatty rats exhibiting full-thickness skin defects with exposed bone and then covered with a bilayer of artificial skin.

Artificial skin has achieved considerable therapeutic results in clinical practice. However, artificial skin treatments for wounds in diabetic patients ...

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

Intraportal Transplantation of Pancreatic Islets in Mouse Model

Pancreatic islet transplantation to reduce hyperglycemia is highly successful in rodents with chemically-induced diabetes. The most common transplantation site in experimental islet transplantation is the kidney capsule. However, as less is known about the interaction of pancreatic islets with blood constituents, it also makes sense to utilize the portal vein approach in experimental islet transplantation.
This protocol demonstrates an intraportal islet transplantation technique in NMRI nude mice. Streptozotocin (180 mg/kg) is injected intraperitoneally to induce hyperglycemia in recipient mice. They are considered as diabetic at a non-fasting blood glucose level greater than 20 mmol/L. One day prior to transplantation, mouse pancreatic islets are isolated from the donor pancreas by collagenase digestion; a minimum of 350 islets are utilized per diabetic recipient. Depending upon the islet isolation yield, two or more donor mice are utilized per recipient. After overnight culture at 37 &#176;C, islets are administered into the recipient liver via the portal vein. After surgery, the mice are protected in red Makrolon houses and observed until are awake. This protocol maintains glycemic control for 120 days in syngeneic mice and 15 days in allogeneic mice.

Pancreatic islet transplantation is a way to achieve normoglycemia in type 1 diabetes. This article focuses on the transplantation technique through the intraportal route to maintain normal glucose levels in diabetic mice.

Pancreatic islet transplantation to reduce hyperglycemia is highly successful in rodents with chemically-induced diabetes. The most common transplantation ...

Inguinal Subcutaneous White Adipose Tissue (ISWAT) Transplantation Model of Murine Islets

Pancreatic islet transplantation is a well-established therapeutic treatment for type 1 diabetes. The kidney capsule is the most commonly used site for islet transplantation in rodent models. However, the tight kidney capsule limits the transplantation of sufficient islets in large animals and humans. The inguinal subcutaneous white adipose tissue (ISWAT), a new subcutaneous space, was found to be a potentially valuable site for islet transplantation. This site has better blood supply than other subcutaneous spaces. Moreover, the ISWAT accommodates a larger islet mass than the kidney capsule, and transplantation into it is simple. This manuscript describes the procedure of mouse islet isolation and transplantation in the ISWAT site of syngeneic diabetic mouse recipients. Using this protocol, murine pancreatic islets were isolated by standard collagenase digestion and a basement membrane matrix hydrogel was used for fixing the purified islets in the ISWAT site. The blood glucose levels of the recipient mice were monitored for more than 100 days. Islet grafts were retrieved at day 100 after transplantation for histological analysis. The protocol for islet transplantation in the ISWAT site described in this manuscript is simple and effective.

Inguinal Subcutaneous White Adipose Tissue ISWAT Transplantation Model of Murine Islets

In this protocol, a method of murine islet isolation and transplantation into the inguinal subcutaneous white adipose tissue is described. Isolated syngeneic murine islets are transplanted into a murine recipient using a basement membrane hydrogel. The blood glucose level of the recipients is monitored, and histology analysis of the islet grafts is performed.

Pancreatic islet transplantation is a well-established therapeutic treatment for type 1 diabetes. The kidney capsule is the most commonly used site for ...

A Method for Islet Transplantation to the Omentum in Mouse

Islet transplantation has been proposed to be a potential treatment for type 1 diabetes. Recent compelling evidence indicates that intravascular islet infusion is far from ideal and therefore, the omentum is re-emerging as a potentially valuable site for islet transplantation. This experiment requires the isolation of high quality islets and the implantation of the islets to the diabetic recipients. Transplantation to the omentum requires surgical steps that can be better demonstrated visually. Here, the detailed steps for this procedure are presented. Two methods of mixing the isolated islets with hydrogel before placing the mixture into the omental pouch of diabetic mice are described here. Different hydrogels are used for the different conditions. Blood glucose levels of diabetic mouse recipients of syngeneic islets in the omentum were monitored for up to 35 days. Some animals were sacrificed after 14 days to perform immuno-histochemical analysis. This pre-clinical transplantation approach can be used as preliminary data leading up to translation to clinical transplantation.

A method for the omental transplantation of islets in a mouse is introduced. The isolated islets are mixed with hydrogel and the mixture is placed into the omental pouch of a diabetic mouse. Then, the blood glucose is monitored, and immuno-histochemical analysis is performed.

Islet transplantation has been proposed to be a potential treatment for type 1 diabetes. Recent compelling evidence indicates that intravascular islet ...

Fat-Covered Islet Transplantation Using Epididymal White Adipose Tissue

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