Name: generation and grafting of tissue-engineered vessels in a mouse model
Uploaded: 2015-03-18T14:00:00
Description: Watch this Scientific Journal Video about Generation and Grafting of Tissue-engineered Vessels in a Mouse Model at JoVE.com

This work was supported by The British Heart Foundation and The Oak Foundation.

לבצע את כל הניסויים בבעלי החיים על פי פרוטוקולים שאושרו על ידי הוועדה המוסדית לשימוש וטיפול בחי מעבדה. 1. הכנת תרבות מדיה <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> הפוך תקשורת ותרבות לשורת תאי פיברובלסטים אנושית CCL-153: F-12K בינוני, 10% בס?...

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הפרוטוקול הנוכחי מצביע על צליל אסטרטגיה, מהירה, פשוטה, יעילה ושחזור שבו יכולים להיות שנוצרו כלי רקמה מהונדסות תפקודיים באמצעות PiPSC מfibroblasts האנושי. טכניקה זו מהווה כלי רב ערך לרפואת רגנרטיבית, הנדסת רקמות וטיפול בתאים שעלולים להיות מטופל ספציפי בעתיד הקרוב. שלבים קריט...

הבנייה של צינורות כלי דם היא אסטרטגיה בסיסית לתיקון כירורגי של כלי נפגעו ונפצעו כתוצאה ממחל לב וכלי דם. עד כה, חומרי שתל המשמשים בניתוחים כוללים ביולוגית פולימרים סינטטיים (polytetrafluoroethylene [טפלון], polytetrafluoroethylene המורחב [ePTFE; גור-Tex] או terephthalate פוליאתילן [דקרון]), allografts, רקמת אוטולוגי (קרום הלב או וריד saphenous) וxenografts 1. בעוד שתלי מלאכותיים (למשל, גורטקס ודקרון) הם נפוצים ביותר, חומרים אלה עלולים לגרום לסיבוכים לטווח קצר וארוך רבים הכוללים היצרות, בתצהיר סידן, thrombo-אמבוליזציה וזיהומים. למרות שמטופלים עם שתלים ביולוגיים נוכחי עם ירידה באירועי thrombo-תסחיפים, הם עדיין נתקלים במגבלות כגון אי ספיקה משנית שתל ועמידות מקוצרת בשל הסתיידות השפלה 2. לכן, למרות שיפור המשמעותי בt כירורגיתechniques במשך השנים, החוקרים וקלינאים עדיין עמוס עם הצורך בזיהוי הצינור האידיאלי למחלות לב וכלי דם. לאחרונה, תחום המחקר של הנדסת רקמות כלי דם יצר מושג שבו תאים משולבים פיגומים מתכלים, במטרה ליצור סביבת biomimetic שמגלמת כלי פונקציונלי להשתלה מוצלחת 1. ביסודו, הצלחתו של בונה כלי הדם תלויה בשלושה מרכיבים חיוניים; תאים המרכיבים את הפיגום, כלומר, שכבה פנימית של תאי האנדותל ושכבת תאי שריר חלק, פיגום המכיל המטריצה ​​תאית המתאימה כדי לספק תכונות מכאניות דומות לכלי הדם המקומיים, ואיתות המולקולרית / סלולרית שנדרש לייזום / ויסות תיקון. patency שתל לטווח ארוך ופיתוח מתמשך של הניאו-רקמות תלויים מאוד בזריעת תאים יעילה של פיגומים, הereby טיוח ההחלטה של ​​סוג תא חשיבות קריטית. מספר דיווחים להדגים את השימוש באנדותל הבוגר ותאי שריר חלק ממקורות שונים לפתח צינורות בקוטר קטן 3-6. למרות מבטיח, חוסר כלי אוטולוגי מספיק כדי להשיג אנדותל הבוגר ותאי שריר חלק יישארו נטל ניכר. לאחרונה, תאי גזע ממקורות שונים שנוצלו עבור יישומי הנדסת רקמות וכלי דם. תאים אכן, תאי גזע pluripotent מגוון של סוגי תאי גזע כוללים תאי גזע עובריים 7, מושרה (iPSCs) 8,9, PiPSC 10,11, נגזר מח עצם mononuclear 12, בתאי גזע mesenchymal 13, ותאי האנדותל וקיר כלי למבוגרים -derived תאי גזע אנטיגן-1 (SCA-1) + תאי גזע / אב 14,15 כולם הודגמו להיות מסוגל בידול לתאי האנדותל או פונקציונלי או שריר חלק בתגובה לתקשורת מוגדרת ותנאי תרבות. יתר על כן, יכולת התחדשות עצמית בלתי מוגבלת של תאי הגזע להפוך אותם מועמדים טובים יותר בניגוד לאנדותל הבוגר ותאי שריר חלק שיכול רק לחלק למספר מוגבל של פעמים לפני שעברו למעצר צמיחה והזדקנות. הבחירה של חומר פיגום כדי ליצור כלי רקמות מהונדס מוצלחות להשתלה תלויה במספר גורמים כגון biocompatibility, תכונות ביו-מכאניות, ושיעור ההתכלות. ביסודו, חומרים המשמשים ליצור פיגומים לשתלים צריכים להיות מתכלה ולא הר תגובות חיסוני נמען מיותר. בנוסף, הוא חייב להקיף נקבוביות מתאים ומייקרו עבור קובץ מצורף תא והישרדות שלאחר מכן. עד כה, החומרים הנפוצים ביותר בשימוש לפיגומים בהנדסת רקמות וכלי דם כוללים פולימרים של חומצות polyglycolic, חומצת polylactic, וε-caprolactone פולי 16. לאחרונה, יש לי חומרים ביולוגיים decellularizedגם יושם בהצלחה מסוימת. מספר מעבדות הראו כי זריעה אנושית decellularized, כלבים או כלי החזיריים עם תאי אוטולוגי סיפקה שתל ביולוגי שהתנגד קרישה והיפרפלזיה intimal 17-19. אסטרטגיות אחרות בהנדסת רקמות וכלי דם כוללות שתלים תאיים כלי דם המבוססים על חלבוני מטריצה ​​למשל, זריעת תאים בג&#39;ל הפיברין 13 וגיליונות תא יצירה ללא תמיכת פיגום 20, 21. הפרוטוקול הנוכחי מדגים את הבידול של PiPSC האנושי לאנדותל הפונקציונלי ותאי שריר חלק, הדור של bioreactor המורכב מפיגום כלי decellularized נמל תאי כלי דם נגזר PiPSC פונקציונליים, והשתלה של כלי הרקמה מהונדסות לכשל חיסוני משולב חמור (SCID עכברים). PiPSC הוא סוג תא אופטימלי לשימוש עבור הנדסת רקמות של שתלי כלי משום שתאים אלה לא יוצרים גידולים בעכברים או להעלות אתי ותגובות allo-חיסונית. יתר על כן, יש לנו הראינו כי האסטרטגיה ליצירת פיפס-אנדותל תאים ופיפס חלק תאי שריר היא יעילה והשחזור 10,11. לאחר מכן, מתכננים כלי decellularized לזריעה של תאי כלי דם נגזר PiPSC לחקות באופן הדוק חלבוני מטריצה ​​שקיים בתוך כלי ילידים, וכך לשפר את יעילות השתלה והישרדות. יתר על כן, decellularization של כלי לפני זריעת PiPSC מונע ההתרחשות של תגובות דלקתיות רכובים על ידי סוגי תאים חיסוניים כגון מקרופאגים. יותר מכך, פרוטוקול זה לא רק מייצג מתודולוגיה כדי ליצור מבטיח צינורות כלי דם לתרגום לבני אדם, אלא גם מספק אמצעי רב ערך של לימוד והבנת המנגנונים המולקולריים השולטים בהתחדשות רקמת כלי דם באמצעות מודלים עכבר.

<table border="0" cellpadding="0" cellspacing="0" >
	<tbody>
		<tr >
			<td >Human Fibroblasts CCL-153</td>
			<td >ATCC</td>
			<td >CCL-153</td>
			<td>Prenatal human embryonic fibroblasts</td>
		</tr>
		<tr >
			<td >ATCC F-12K Medium (Kaighn&#39;s Modification of Ham&#39;s F-12 Medium)</td>
			<td >ATCC</td>
			<td >30-2004</td>
			<td></td>
		</tr>
		<tr >
			<td >Fetal Bovine Serum</td>
			<td >ATCC</td>
			<td >30-2020</td>
			<td></td>
		</tr>
		<tr >
			<td >Knockout DMEM medium optimized for embryonic stem cells</td>
			<td >Life technologies (Gibco)</td>
			<td >12660-012</td>
			<td></td>
		</tr>
		<tr >
			<td >Knockout Serum Replacement</td>
			<td >Life technologies (Invitrogen)</td>
			<td >10828-028</td>
			<td></td>
		</tr>
		<tr >
			<td >Human Basic FGF-2&#160;</td>
			<td >Miltenyi Biotech</td>
			<td >130-093-837</td>
			<td></td>
		</tr>
		<tr >
			<td >alpha-MEM medium</td>
			<td >Life technologies (Invitrogen)</td>
			<td >32571093</td>
			<td></td>
		</tr>
		<tr >
			<td >Human PDGF</td>
			<td >R&#38;D System</td>
			<td >120-HD-001</td>
			<td></td>
		</tr>
		<tr >
			<td >Gelatin Solution 2%</td>
			<td >Sigma</td>
			<td >G1393</td>
			<td></td>
		</tr>
		<tr >
			<td >Plasmid 20866: pCAG2LMKOSimO (SOX2, OCT4, KLF4, C-MYC)</td>
			<td >Addgene</td>
			<td >20866</td>
			<td></td>
		</tr>
		<tr >
			<td >&#160;PvuI Restriction Enzyme</td>
			<td >New England Biolabs</td>
			<td >RO150S</td>
			<td></td>
		</tr>
		<tr >
			<td >SureClean Plus</td>
			<td >Bioline</td>
			<td >BIO-37047</td>
			<td></td>
		</tr>
		<tr >
			<td >Nucelofection Kit (NHDF Kit)</td>
			<td >LONZA</td>
			<td >VPD-1001</td>
			<td></td>
		</tr>
		<tr >
			<td >Neomycin</td>
			<td >SIGMA</td>
			<td >G418</td>
			<td>Selection of&#160;</td>
		</tr>
		<tr >
			<td >KL 1500 LCD, Illumination for Stereo Microscopy</td>
			<td >SCHOTT</td>
			<td >KL 1500 LCD</td>
			<td>Cold light illumination for stereo microscopy</td>
		</tr>
		<tr >
			<td >Nikon Zoom Steromicroscope SMZ800</td>
			<td >Nikon</td>
			<td >SMZ800</td>
			<td></td>
		</tr>
		<tr >
			<td >Heparin sodium salt</td>
			<td >Sigma</td>
			<td >H3393</td>
			<td></td>
		</tr>
		<tr >
			<td >10% SDS Stock Solution Molecular Biology Reagent</td>
			<td >Severn Biotech</td>
			<td >CAS 151-21-3</td>
			<td></td>
		</tr>
		<tr >
			<td >Dulbecco&#39;s Phosphate Buffered Saline</td>
			<td >Sigma</td>
			<td >D8537</td>
			<td></td>
		</tr>
		<tr >
			<td >Matrigel (10mg/ml)</td>
			<td >BD</td>
			<td >A6661</td>
			<td></td>
		</tr>
		<tr >
			<td >Shaker IKA Vibrax with Shaking platform VX 7&#160;</td>
			<td >Jepson Bolton&#39;s, Janke&#38;Kunkel</td>
			<td >S32-102</td>
			<td></td>
		</tr>
		<tr >
			<td >Masterflex L/S Digital Pump Drive</td>
			<td >Cole-Parmer</td>
			<td >WZ-07523-80</td>
			<td></td>
		</tr>
		<tr >
			<td >Masterflex L/S 6-channel, 6-roller cartridge pump head</td>
			<td >Cole-Parmer</td>
			<td >EW-07519-15</td>
			<td></td>
		</tr>
		<tr >
			<td >Masterflex L/S large cartridges for pump head</td>
			<td >Cole-Parmer</td>
			<td >EW-07519-75</td>
			<td></td>
		</tr>
		<tr >
			<td >Masterflex platinum-cured silicone pump tubing, L/S 14, 25 ft</td>
			<td >Cole-Parmer&#160;</td>
			<td >WZ-96410-14</td>
			<td >Tubing goes through the peristaltic pump</td>
		</tr>
		<tr >
			<td >0.5mm ID, 0.8 mm OD Silicone Tubing</td>
			<td >SILEX</td>
			<td >N/A</td>
			<td>Tubings connect incubation chamber, media reservoir and compliance chamber&#160;</td>
		</tr>
		<tr >
			<td >Fitting Reducer 0.5 to 1.6, natural Polypropyline</td>
			<td >Ibidi</td>
			<td >10829</td>
			<td>Adapter connect above two types of tubings</td>
		</tr>
		<tr >
			<td >1/32&#34; Tubing, ID 0.01&#34; (250&#181;m) Material: PEEK</td>
			<td >LabSmith</td>
			<td >T-132-010P</td>
			<td>Tubing through the incubation chamber wall which connects the graft with outside tubing</td>
		</tr>
		<tr >
			<td >One-Piece Fittings&#160;</td>
			<td >LabSmith</td>
			<td >T-132-100</td>
			<td>Fix the above tubings through the incubation chamber wall</td>
		</tr>
		<tr >
			<td >Nylon tubes (OD 0.9mm, ID 0.75mm)&#160;</td>
			<td >Smiths Medical</td>
			<td >N/A</td>
			<td>Tubings insert into two ends of the aorta graft</td>
		</tr>
		<tr >
			<td >NOD.CB17-Prkdcscid/NcrCrl mouse</td>
			<td >Charles River</td>
			<td ></td>
			<td ></td>
		</tr>
		<tr >
			<td >Surgical sutures, 8-0&#160; silk</td>
			<td >ETHICON</td>
			<td >W819</td>
			<td ></td>
		</tr>
		<tr >
			<td >Hypnorm</td>
			<td >Vetapharm</td>
			<td >Vm21757/4000</td>
			<td >Neuroleptanalgesic for use in mice</td>
		</tr>
		<tr >
			<td >Hypnovel (Midazolam)</td>
			<td >Roche</td>
			<td >59467-70-8</td>
			<td >Induction of anaesthesia</td>
		</tr>
		<tr >
			<td >Dissecting microscope</td>
			<td >Carl Zeiss</td>
			<td >Stemi 2000</td>
			<td ></td>
		</tr>
		<tr >
			<td >Nylon Tubing</td>
			<td >Portex LTD</td>
			<td >800/200/100/200</td>
			<td >0.65 mm in diameter and 1 mm in length; to make artery cuff</td>
		</tr>
		<tr >
			<td >Electrocoagulator</td>
			<td >Martin&#160;</td>
			<td >SN 54.131</td>
			<td >Ligation of artery branches on aorta</td>
		</tr>
		<tr >
			<td >Bipolar micro hemostat forceps</td>
			<td >Martin</td>
			<td >80-91-12-04</td>
			<td >Fixation of vessel ends</td>
		</tr>
		<tr >
			<td >Vessel Dilator</td>
			<td >S&#38;T</td>
			<td >JFX-7</td>
			<td ></td>
		</tr>
		<tr >
			<td >Vessel Dilator</td>
			<td >S&#38;T</td>
			<td >JFL-3dZ</td>
			<td ></td>
		</tr>
		<tr >
			<td >Vessel Dilator</td>
			<td >S&#38;T</td>
			<td >D-5aZ</td>
			<td ></td>
		</tr>
		<tr >
			<td >Mini applier&#160;</td>
			<td >AESCULAP</td>
			<td >FE572K</td>
			<td ></td>
		</tr>
		<tr >
			<td >Micro hemostats clips</td>
			<td >AESCULAP</td>
			<td >FE720K</td>
			<td ></td>
		</tr>
		<tr >
			<td >Surgical sutures, 6-0 VICRYL</td>
			<td >ETHICON</td>
			<td >V489</td>
			<td ></td>
		</tr>
	</tbody>
</table>

generation and grafting of tissue-engineered vessels in a mouse model

The construction of vascular conduits is a fundamental strategy for surgical repair of damaged and injured vessels resulting from cardiovascular diseases. The current protocol presents an efficient and reproducible strategy in which functional tissue engineered vessel grafts can be generated using partially induced pluripotent stem cell (PiPSC) from human fibroblasts. We designed a decellularized vessel scaffold bioreactor, which closely mimics the matrix protein structure and blood flow that exists within a native vessel, for seeding of PiPSC-endothelial cells or smooth muscle cells prior to grafting into mice. This approach was demonstrated to be advantageous because immune-deficient mice engrafted with the PiPSC-derived grafts presented with markedly increased survival rate 3 weeks after surgery. This protocol represents a valuable tool for regenerative medicine, tissue engineering and potentially patient-specific cell-therapy in the near future.

הדור המוצלח של PiPSC אושר 4 ימים לאחר nucleofecting fibroblasts אדם עם פלסמיד pCAG2LMKOSimO ינארית ביצוע 4 גורמי שעתוק, Oct4, Sox2, KLF4 וc-MYC (OSKM). PiPSC מוצג פנוטיפ ניכר מובהק בהשוואה לfibroblasts (איור 2 א) והביע גורמי תכנות מחדש 4 בmRNA (איור 2) וחלבון רמות (איור 2 ג) 10. היעילות ...

Watch this Scientific Journal Video about Generation and Grafting of Tissue-engineered Vessels in a Mouse Model at JoVE.com

Generation and Grafting of Tissue-engineered Vessels in a Mouse Model

כאן, אנו מציגים פרוטוקול לייצר שתלי כלי רקמה מהונדסת, כי הם פונקציונליים להשתלה לעכברים על ידי זריעה כפולה תאי גזע pluripotent מושרה באופן חלקי (PiPSC) - נגזר תאי שריר חלק וPiPSC - תאי האנדותל נגזרו על bioreactor פיגום כלי decellularized.

דור והארכת כלי רקמות מהונדסות במודל עכבר

The construction of vascular conduits is a fundamental strategy for surgical repair of damaged and injured vessels resulting from cardiovascular diseases. ...

generation-and-grafting-of-tissue-engineered-vessels-in-a-mouse-model

Research

JoVE Journal

Bioengineering

Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process. Traditional in vitro pulse duplicator systems are not configured to accommodate flexible tri-leaflet materials; in addition, assessment of polymer valve functionality needs to be made in a relative context to native and prosthetic heart valves under identical test conditions so that variability in measurements from different instruments can be avoided. Accordingly, we conducted hydrodynamic assessment of i) native (n = 4, mean diameter, D = 20 mm), ii) bi-leaflet mechanical (n= 2, D = 23 mm) and iii) polymer valves (n = 5, D = 22 mm) via the use of a commercially available pulse duplicator system (ViVitro Labs Inc, Victoria, BC) that was modified to accommodate tri-leaflet valve geometries. Tri-leaflet silicone valves developed at the University of Florida comprised the polymer valve group. A mixture in the ratio of 35:65 glycerin to water was used to mimic blood physical properties. Instantaneous flow rate was measured at the interface of the left ventricle and aortic units while pressure was recorded at the ventricular and aortic positions. Bi-leaflet and native valve data from the literature was used to validate flow and pressure readings. The following hydrodynamic metrics were reported: forward flow pressure drop, aortic root mean square forward flow rate, aortic closing, leakage&#160;and regurgitant volume, transaortic closing, leakage, and total energy losses. Representative results indicated that hydrodynamic metrics from the three valve groups could be successfully obtained by incorporating a custom-built assembly into a commercially available pulse duplicator system and subsequently, objectively compared to provide insights on functional aspects of polymer valve design.

There has been renewed interest in developing polymer valves. Here, the objectives are to demonstrate the feasibility of modifying a commercial pulse duplicator to accommodate tri-leaflet geometries and to define a protocol to present polymer valve hydrodynamic data in comparison to native and prosthetic valve data collected under near-identical conditions.

פרוטוקול להערכה הידרודינמית יחסית של הפולימר שסתום Tri-עלון

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of ...

Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is presented. The polymerization from the membrane surface is induced by plasma treatment of the membrane, followed by reacting the membrane surface with a methanolic solution of 2-hydroxyethyl methacrylate (HEMA). Special attention is given to the process parameters for the plasma treatment prior to the polymerization on the surface. For example, the influence of the plasma-treatment on different types of membranes (e.g.&#160;polyester, polycarbonate, polyvinylidene fluoride) is studied. Furthermore, the time-dependent stability of the surface-grafted membranes is shown by contact angle measurements. When grafting poly(2-hydroxyethyl methacrylate) (PHEMA) in this way, the surface can be further modified by esterification of the alcohol moiety of the polymer with a carboxylic acid function of the desired substance. These reactions can therefore be used for the functionalization of the membrane surface. For example, the surface tension of the membrane can be changed or a desired functionality as the presented light-responsiveness can be inserted. This is demonstrated by reacting PHEMA with a carboxylic acid functionalized spirobenzopyran unit which leads to a light-responsive membrane. The choice of solvent plays a major role in the postmodification step and is discussed in more detail in this paper. The permeability measurements of such functionalized membranes are performed using a Franz cell with an external light source. By changing the wavelength of the light from the visible to the UV-range, a change of permeability of aqueous caffeine solutions is observed.

A plasma-induced polymerization procedure is described for the surface-initiated polymerization on polymer membranes. Further postmodification of the grafted polymer with photochromic substances is presented with a protocol of conducting permeability measurements of light-responsive membranes.

הכנה של ממברנות אור תגובה על ידי הארכת משטח משולבת ותהליך Postmodification

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is ...

Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring

The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large animal model. A step by-step protocol for inter-positional placement of the TEV and real-time digital assessment of the TEV and native carotid arteries is described here. In vivo monitoring is made possible by the implantation of flow probes, catheters and ultrasonic crystals (capable of recording dynamic diameter changes of implanted TEVs and native carotid arteries) at the time of surgery. Once implanted, researchers can calculate arterial blood flow patterns, invasive blood pressure and artery diameter yielding parameters such as pulse wave velocity, augmentation index, pulse pressures and compliance. Data acquisition is accomplished using a single computer program for analysis throughout the duration of the experiment. Such invaluable data provides insight into TEV matrix remodeling, its resemblance to native/sham controls and overall TEV performance in vivo.

Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring

A step-by-step protocol for the inter-positional placement of Tissue Engineered Vessels (TEVs) into the carotid artery of a sheep using end-to-end anastomosis and real-time digital assessment in vivo until animal sacrifice.

טכניקה כירורגית להשתלה של רקמות שתלי כלי דם מהונדסים ולאחר<em&gt; In vivo</em&gt; ניטור

The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large ...

Generation of a Three-dimensional Full Thickness Skin Equivalent and Automated Wounding

In vitro models are a cost effective and ethical alternative to study cutaneous wound healing processes. Moreover, by using human cells, these models reflect the human wound situation better than animal models. Although two-dimensional models are widely used to investigate processes such as cellular migration and proliferation, models that are more complex are required to gain a deeper knowledge about wound healing. Besides a suitable model system, the generation of precise and reproducible wounds is crucial to ensure comparable results between different test runs. In this study, the generation of a three-dimensional full thickness skin equivalent to study wound healing is shown. The dermal part of the models is comprised of human dermal fibroblast embedded in a rat-tail collagen type I hydrogel. Following the inoculation with human epidermal keratinocytes and consequent culture at the air-liquid interface, a multilayered epidermis is formed on top of the models. To study the wound healing process, we additionally developed an automated wounding device, which generates standardized wounds in a sterile atmosphere.

The goal of this protocol is to build up a three-dimensional full thickness skin equivalent, which resembles natural skin. With a specifically constructed automated wounding device, precise and reproducible wounds can be generated under maintenance of sterility.

דור של עור בעובי מלא תלת ממדי Equivalent ואוטומטי פציעה

In vitro models are a cost effective and ethical alternative to study cutaneous wound healing processes. Moreover, by using human cells, these models ...

Production, Characterization and Potential Uses of a 3D Tissue-engineered Human Esophageal Mucosal Model

The incidence of both esophageal adenocarcinoma and its precursor, Barrett&#8217;s Metaplasia, are rising rapidly in the western world. Furthermore esophageal adenocarcinoma generally has a poor prognosis, with little improvement in survival rates in recent years. These are difficult conditions to study and there has been a lack of suitable experimental platforms to investigate disorders of the esophageal mucosa.
A model of the human esophageal mucosa has been developed in the MacNeil laboratory which, unlike conventional 2D cell culture systems, recapitulates the cell-cell and cell-matrix interactions present in vivo and produces a mature, stratified epithelium similar to that of the normal human esophagus. Briefly, the model utilizes non-transformed normal primary human esophageal fibroblasts and epithelial cells grown within a porcine-derived acellular esophageal scaffold. Immunohistochemical characterization of this model by CK4, CK14, Ki67 and involucrin staining demonstrates appropriate recapitulation of the histology of the normal human esophageal mucosa.
This model provides a robust, biologically relevant experimental model of the human esophageal mucosa. It can easily be manipulated to investigate a number of research questions including the effectiveness of pharmacological agents and the impact of exposure to environmental factors such as alcohol, toxins, high temperature or gastro-esophageal refluxate components. The model also facilitates extended culture periods not achievable with conventional 2D cell culture, enabling, inter alia, the study of the impact of repeated exposure of a mature epithelium to the agent of interest for up to 20 days. Furthermore, a variety of cell lines, such as those derived from esophageal tumors or Barrett&#8217;s Metaplasia, can be incorporated into the model to investigate processes such as tumor invasion and drug responsiveness in a more biologically relevant environment.

This manuscript describes the production, characterization and potential uses of a tissue engineered 3D esophageal construct prepared from normal primary human esophageal fibroblast and squamous epithelial cells seeded within a de-cellularized porcine scaffold. The results demonstrate the formation of a mature stratified epithelium similar to the normal human esophagus.

ייצור, אפיון ופוטנציאל שימושים של הוושט רירי דגם אדם מהונדס-רקמות 3D

The incidence of both esophageal adenocarcinoma and its precursor, Barrett&#8217;s Metaplasia, are rising rapidly in the western world. Furthermore ...

A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds

In the present study, we combined an in vitro 3D lung tumor model with an in silico model to optimize predictions of drug response based on a specific mutational background. The model is generated on a decellularized porcine scaffold that reproduces tissue-specific characteristics regarding extracellular matrix composition and architecture including the basement membrane. We standardized a protocol that allows artificial tumor tissue generation within 14 days including three days of drug treatment. Our article provides several detailed descriptions of 3D read-out screening techniques like the determination of the proliferation index Ki67 staining&#39;s, apoptosis from supernatants by M30-ELISA and assessment of epithelial to mesenchymal transition (EMT), which are helpful tools for evaluating the effectiveness of therapeutic compounds. We could show compared to 2D culture a reduction of proliferation in our 3D tumor model that is related to the clinical situation. Despite of this lower proliferation, the model predicted EGFR-targeted drug responses correctly according to the biomarker status as shown by comparison of the lung carcinoma cell lines HCC827 (EGFR -mutated, KRAS wild-type) and A549 (EGFR wild-type, KRAS-mutated) treated with the tyrosine-kinase inhibitor (TKI) gefitinib. To investigate drug responses of more advanced tumor cells, we induced EMT by long-term treatment with TGF-beta-1 as assessed by vimentin/pan-cytokeratin immunofluorescence staining. A flow-bioreactor was employed to adjust culture to physiological conditions, which improved tissue generation. Furthermore, we show the integration of drug responses upon gefitinib treatment or TGF-beta-1 stimulation - apoptosis, proliferation index and EMT - into a Boolean in silico model. Additionally, we explain how drug responses of tumor cells with a specific mutational background and counterstrategies against resistance can be predicted. We are confident that our 3D in vitro approach especially with its in silico expansion provides an additional value for preclinical drug testing in more realistic conditions than in 2D cell culture.

A Combined 3D Tissue Engineered In Vitro/In Silico Lung Tumor Model for Predicting Drug Effectiveness in Specific Mutational Backgrounds

We present a three-dimensional (3D) lung cancer model based on a biological collagen scaffold to study sensitivity towards non-small-cell-lung-cancer-(NSCLC)-targeted therapies. We demonstrate different read-out techniques to determine the proliferation index, apoptosis and epithelial-mesenchymal transition (EMT) status. Collected data are integrated into an in silico model for prediction of drug sensitivity.

רקמת 3D משולב תכנון הנדסי<em&gt; במבחנה</em&gt; /<em&gt; סיליקו</em&gt; דגם גידול ריאות לניבוי יעילות טיפול תרופתי רקעים מוטציוני ספציפיים

In the present study, we combined an in vitro 3D lung tumor model with an in silico model to optimize predictions of drug response based on a specific ...

Applications of In Vivo Functional Testing of the Rat Tibialis Anterior for Evaluating Tissue Engineered Skeletal Muscle Repair

Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from traumatic injury, disease and various congenital, genetic and acquired conditions are quite common. Tissue engineering and regenerative medicine technologies have enormous potential to provide a therapeutic solution. However, utilization of biologically relevant animal models in combination with longitudinal assessments of pertinent functional measures are critical to the development of improved regenerative therapeutics for treatment of VML-like injuries. In that regard, a commercial muscle lever system can be used to measure length, tension, force and velocity parameters in skeletal muscle. We used this system, in conjunction with a high power, bi-phase stimulator, to measure in vivo force production in response to activation of the anterior crural compartment of the rat hindlimb. We have previously used this equipment to assess the functional impact of VML injury on the tibialis anterior (TA) muscle, as well as the extent of functional recovery following treatment of the injured TA muscle with our tissue engineered muscle repair (TEMR) technology. For such studies, the left foot of an anaesthetized rat is securely anchored to a footplate linked to a servomotor, and the common peroneal nerve is stimulated by two percutaneous needle electrodes to elicit muscle contraction and dorsiflexion of the foot. The peroneal nerve stimulation-induced muscle contraction is measured over a range of stimulation frequencies (1-200 Hz), to ensure an eventual plateau in force production that allows for an accurate determination of peak tetanic force. In addition to evaluation of the extent of VML injury as well as the degree of functional recovery following treatment, this methodology can be easily applied to study diverse aspects of muscle physiology and pathophysiology. Such an approach should assist with the more rational development of improved therapeutics for muscle repair and regeneration.

Applications of In Vivo Functional Testing of the Rat Tibialis Anterior for Evaluating Tissue Engineered Skeletal Muscle Repair

We describe an in vivo protocol to measure dorsiflexion of the foot following stimulation of the peroneal nerve and contraction of the anterior crural compartment of the rat hindlimb. Such measurements are an indispensable translational tool for evaluating skeletal muscle pathology and tissue engineering approaches to muscle repair and regeneration.

יישומים של<em&gt; In vivo</em&gt; בדיקות פונקציונליות של עכברוש השוקה הקדמי להערכת רקמות מהונדסות תיקון שרירי שלד

Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from ...

Three-dimensional Tissue Engineered Aligned Astrocyte Networks to Recapitulate Developmental Mechanisms and Facilitate Nervous System Regeneration

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to replace lost neurons and regenerate axonal pathways. However, during nervous system development, neuronal migration and axonal extension often occur along pathways formed by other cells, referred to as &#34;living scaffolds&#34;. Seeking to emulate these mechanisms and to design a strategy that circumvents the inhibitory environment of the CNS, this manuscript presents a protocol to fabricate tissue engineered astrocyte-based &#34;living scaffolds&#34;. To create these constructs, we employed a novel biomaterial encasement scheme to induce astrocytes to self-assemble into dense three-dimensional bundles of bipolar longitudinally-aligned somata and processes. First, hollow hydrogel micro-columns were assembled, and the inner lumen was coated with collagen extracellular-matrix. Dissociated cerebral cortical astrocytes were then delivered into the lumen of the cylindrical micro-column and, at a critical inner diameter of &#60;350 &#181;m, spontaneously self-aligned and contracted to produce long fiber-like cables consisting of dense bundles of astrocyte processes and collagen fibrils measuring &#60;150 &#181;m in diameter yet extending several cm in length. These engineered living scaffolds exhibited &#62;97% cell viability and were virtually exclusively comprised of astrocytes expressing a combination of the intermediate filament proteins glial-fibrillary acidic protein (GFAP), vimentin, and nestin. These aligned astrocyte networks were found to provide a permissive substrate for neuronal attachment and aligned neurite extension. Moreover, these constructs maintain integrity and alignment when extracted from the hydrogel encasement, making them suitable for CNS implantation. These preformed constructs structurally emulate key cytoarchitectural elements of naturally occurring glial-based &#34;living scaffolds&#34; in vivo. As such, these engineered living scaffolds may serve as test-beds to study neurodevelopmental mechanisms in vitro or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding following CNS degeneration in vivo.

We showcase the development of self-assembled, three-dimensional bundles of longitudinally aligned astrocytic somata and processes within a novel biomaterial encasement. These engineered &#34;living scaffolds&#34;, exhibiting micron-scale diameter yet extending centimeters in length, may serve as test-beds to study neurodevelopmental mechanisms or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding.

תלת מימדי רקמות מהונדסים מיושר אסטרוציט רשתות כדי לסכם מנגנונים התפתחותית וכדי להקל על מערכת העצבים התחדשות

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to ...

A Novel Tenorrhaphy Suture Technique with Tissue Engineered Collagen Graft to Repair Large Tendon Defects

Surgical management of large tendon defects with tendon grafts is challenging, as there are a finite number of sites where donors can be readily identified and used. Currently, this gap is filled with tendon auto-, allo-, xeno-, or artificial grafts, but clinical methods to secure them are not necessarily translatable to animals because of the scale. In order to evaluate new biomaterials or study a tendon graft made up of collagen type 1, we have developed a modified suture technique to help maintain the engineered tendon in alignment with the tendon ends. Mechanical properties of these grafts are inferior to the native tendon. To incorporate engineered tendon into clinically relevant models of loaded repair, a strategy was adopted to offload the tissue engineered tendon graft and allow for the maturation and integration of the engineered tendon in vivo until a mechanically sound neo-tendon was formed. We describe this technique using incorporation of the collagen type 1 tissue engineered tendon construct.

In this paper, we present an in vitro and in situ protocol to repair a tendon gap of up to 1.5 cm by filling it with engineered collagen graft. This was performed by developing a modified suture technique to take the mechanical load until the graft matures into the host tissue.

טכניקת תפירת טנורהאפי חדשנית עם שתל קולגן מהונדס רקמה לתיקון פגמים גדולים בגיד

Surgical management of large tendon defects with tendon grafts is challenging, as there are a finite number of sites where donors can be readily ...

Seeding and Implantation of a Biosynthetic Tissue-engineered Tracheal Graft in a Mouse Model

Treatment options for congenital or secondary long segment tracheal defects have historically been limited due to an inability to replace functional tissue. Tissue engineering holds great promise as a potential solution with its ability to integrate cells and signaling molecules into a 3-dimensional scaffold. Recent work with tissue engineered tracheal grafts (TETGs) has seen some success but their translation has been limited by graft stenosis, graft collapse, and delayed epithelialization. In order to investigate the mechanisms driving these issues, we have developed a mouse model for tissue engineered tracheal graft implantation. TETGs were constructed using electrospun polymers polyethylene terephthalate (PET) and polyurethane (PU) in a mixture of PET and PU (20:80 percent weight). Scaffolds were then seeded using bone marrow mononuclear cells isolated from 6-8 week-old C57BL/6 mice by gradient centrifugation. Ten million cells per graft were seeded onto the lumen of the scaffold and allowed to incubate overnight before implantation between the third and seventh tracheal rings. These grafts were able to recapitulate the findings of stenosis and delayed epithelialization as demonstrated by histological analysis and lack of Keratin 5 and Keratin 14 basal epithelial cells on immunofluorescence. This model will serve as a tool for investigating cellular and molecular mechanisms involved in host remodeling.

Graft stenosis poses a critical obstacle in tissue engineered airway replacement. To investigate cellular mechanisms underlying stenosis, we utilize a murine model of tissue engineered tracheal replacement with seeded bone marrow mononuclear cells (BM-MNC). Here, we detail our protocol, including scaffold manufacturing, BM-MNC isolation, graft seeding, and implantation.

Seeding, השרשת biosynthetic הוחלף נגזר רקמות מהונדסים בקנה הנשימה השתלה במודל של עכברים

Treatment options for congenital or secondary long segment tracheal defects have historically been limited due to an inability to replace functional ...