Name: isolation of murine adipose tissue-derived microvascular fragments as vascularization units for tissue engineering
Uploaded: 2017-04-30T13:00:00
Description: Watch this Scientific Journal Video about Isolation of Murine Adipose Tissue-derived Microvascular Fragments as Vascularization Units for Tissue Engineering at JoVE.com

We are grateful for the excellent technical assistance of Janine Becker, Caroline Bickelmann and Ruth Nickels. This study was funded by a grant of the Deutsche Forschungsgemeinschaft (DFG - German Research Foundation) - LA 2682/7-1.

All procedures were performed according to the National Institute of Health guidelines for the use of experimental animals and followed institutional guidelines (Landesamt f&#252;r Soziales, Gesundheit und Verbraucherschutz, Abt. Lebensmittel- und Veterin&#228;rwesen, Zentralstelle, Saarbr&#252;cken, Germany).
1. Preparation of Surgical Instruments
<ol>
	<li>Keep ready the dissection scissors, surgical forceps, small preparation scissors, fine forceps and a sterile Petri dish with 15 mL Dulb...

<ol>
	<li>Langer, R., Vacanti, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+engineering.">Tissue engineering.</a> Science. 260 (5110), 920-926 (1993).</li><li>Khademhosseini, A., Langer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+decade+of+progress+in+tissue+engineering.">A decade of progress in tissue engineering.</a> Nat Protoc. 11 (10), 1775-1781 (2016).</li><li>Novosel, E. C., Kleinhans, C., Kluger, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascularization+is+the+key+challenge+in+tissue+engineering.">Vascularization is the key challenge in tissue engineering.</a> Adv Drug Deliv Rev. 63 (4-5), 300-311 (2011).</li><li>Rouwkema, J., Khademhosseini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascularization+and+Angiogenesis+in+Tissue+Engineering:+Beyond+Creating+Static+Networks.">Vascularization and Angiogenesis in Tissue Engineering: Beyond Creating Static Networks.</a> Trends Biotechnol. 34 (9), 733-745 (2016).</li><li>Laschke, M. W., Menger, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascularization+in+tissue+engineering:+angiogenesis+versus+inosculation.">Vascularization in tissue engineering: angiogenesis versus inosculation.</a> Eur Surg Res. 48 (2), 85-92 (2012).</li><li>Sarker, M., Chen, X. B., Schreyer, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+approaches+to+vascularisation+within+tissue+engineering+constructs.">Experimental approaches to vascularisation within tissue engineering constructs.</a> J Biomater Sci Polym Ed. 26 (12), 683-734 (2015).</li><li>Frueh, F. S., Menger, M. D., Lindenblatt, N., Giovanoli, P., Laschke, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+and+emerging+vascularization+strategies+in+skin+tissue+engineering.">Current and emerging vascularization strategies in skin tissue engineering.</a> Crit Rev Biotechnol. 20, 1-13 (2016).</li><li>Utzinger, U., Baggett, B., Weiss, J. A., Hoying, J. B., Edgar, L. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large-scale+time+series+microscopy+of+neovessel+growth+during+angiogenesis.">Large-scale time series microscopy of neovessel growth during angiogenesis.</a> Angiogenesis. 18 (3), 219-232 (2015).</li><li>Laschke, M. W., Menger, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevascularization+in+tissue+engineering:+Current+concepts+and+future+directions.">Prevascularization in tissue engineering: Current concepts and future directions.</a> Biotechnol Adv. 34 (2), 112-121 (2016).</li><li>Baiguera, S., Ribatti, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelialization+approaches+for+viable+engineered+tissues.">Endothelialization approaches for viable engineered tissues.</a> Angiogenesis. 16 (1), 1-14 (2013).</li><li>Wagner, R. C., Kreiner, P., Barrnett, R. J., Bitensky, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biochemical+characterization+and+cytochemical+localization+of+a+catecholamine-sensitive+adenylate+cyclase+in+isolated+capillary+endothelium.">Biochemical characterization and cytochemical localization of a catecholamine-sensitive adenylate cyclase in isolated capillary endothelium.</a> Proc Natl Acad Sci U S A. 69 (11), 3175-3179 (1972).</li><li>Wagner, R. C., Matthews, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+isolation+and+culture+of+capillary+endothelium+from+epididymal+fat.">The isolation and culture of capillary endothelium from epididymal fat.</a> Microvasc Res. 10 (3), 286-297 (1975).</li><li>Laschke, M. W., Menger, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue-derived+microvascular+fragments:+natural+vascularization+units+for+regenerative+medicine.">Adipose tissue-derived microvascular fragments: natural vascularization units for regenerative medicine.</a> Trends Biotechnol. 33 (8), 442-448 (2015).</li><li>Laschke, M. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascularisation+of+porous+scaffolds+is+improved+by+incorporation+of+adipose+tissue-derived+microvascular+fragments.">Vascularisation of porous scaffolds is improved by incorporation of adipose tissue-derived microvascular fragments.</a> Eur Cell Mater. 24, 266-277 (2012).</li><li>Frueh, F. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue-derived+microvascular+fragments+improve+vascularization,+lymphangiogenesis+and+integration+of+dermal+skin+substitutes.">Adipose tissue-derived microvascular fragments improve vascularization, lymphangiogenesis and integration of dermal skin substitutes.</a> J Invest Dermatol. 137 (1), 217-227 (2017).</li><li>McDaniel, J. S., Pilia, M., Ward, C. L., Pollot, B. E., Rathbone, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+and+multilineage+potential+of+cells+derived+from+isolated+microvascular+fragments.">Characterization and multilineage potential of cells derived from isolated microvascular fragments.</a> J Surg Res. 192 (1), 214-222 (2014).</li><li>Nakano, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+autotransplantation+of+microvessel+fragments+on+experimental+random-pattern+flaps+in+the+rat.">Effect of autotransplantation of microvessel fragments on experimental random-pattern flaps in the rat.</a> Eur Surg Res. 30 (3), 149-160 (1998).</li><li>Nakano, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Successful+autotransplantation+of+microvessel+fragments+into+the+rat+heart.">Successful autotransplantation of microvessel fragments into the rat heart.</a> Eur Surg Res. 31 (3), 240-248 (1999).</li><li>Shepherd, B. R., Hoying, J. B., Williams, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microvascular+transplantation+after+acute+myocardial+infarction.">Microvascular transplantation after acute myocardial infarction.</a> Tissue Eng. 13 (12), 2871-2879 (2007).</li><li>Pilia, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transplantation+and+perfusion+of+microvascular+fragments+in+a+rodent+model+of+volumetric+muscle+loss+injury.">Transplantation and perfusion of microvascular fragments in a rodent model of volumetric muscle loss injury.</a> Eur Cell Mater. 28, 11-23 (2014).</li><li>Laschke, M. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue-derived+microvascular+fragments+from+aged+donors+exhibit+an+impaired+vascularisation+capacity.">Adipose tissue-derived microvascular fragments from aged donors exhibit an impaired vascularisation capacity.</a> Eur Cell Mater. 28, 287-298 (2015).</li><li>Okabe, M., Ikawa, M., Kominami, K., Nakanishi, T., Nishimune, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term='Green+mice'+as+a+source+of+ubiquitous+green+cells.">'Green mice' as a source of ubiquitous green cells.</a> FEBS Lett. 407 (3), 313-319 (1997).</li><li>Honek, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modulation+of+age-related+insulin+sensitivity+by+VEGF-dependent+vascular+plasticity+in+adipose+tissues.">Modulation of age-related insulin sensitivity by VEGF-dependent vascular plasticity in adipose tissues.</a> Proc Natl Acad Sci U S A. 111 (41), 14906-14911 (2014).</li><li>Cho, C. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angiogenic+role+of+LYVE-1-positive+macrophages+in+adipose+tissue.">Angiogenic role of LYVE-1-positive macrophages in adipose tissue.</a> Circ Res. 100 (4), e47-e57 (2007).</li><li>Han, S., Sun, H. M., Hwang, K. C., Kim, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose-Derived+Stromal+Vascular+Fraction+Cells:+Update+on+Clinical+Utility+and+Efficacy.">Adipose-Derived Stromal Vascular Fraction Cells: Update on Clinical Utility and Efficacy.</a> Crit Rev Eukaryot Gene Expr. 25 (2), 145-152 (2015).</li><li>Chen, Y. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+Differentiation+of+Adipose-Derived+Stem+Cells+from+Porcine+Subcutaneous+Adipose+Tissues.">Isolation and Differentiation of Adipose-Derived Stem Cells from Porcine Subcutaneous Adipose Tissues.</a> J Vis Exp. (109), e53886 (2016).</li><li>Guillaume-Jugnot, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Autologous+adipose-derived+stromal+vascular+fraction+in+patients+with+systemic+sclerosis:+12-month+follow-up.">Autologous adipose-derived stromal vascular fraction in patients with systemic sclerosis: 12-month follow-up.</a> Rheumatology (Oxford). 55 (2), 301-306 (2016).</li><li>Tissiani, L. A., Alonso, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Prospective+and+Controlled+Clinical+Trial+on+Stromal+Vascular+Fraction+Enriched+Fat+Grafts+in+Secondary+Breast+Reconstruction.">A Prospective and Controlled Clinical Trial on Stromal Vascular Fraction Enriched Fat Grafts in Secondary Breast Reconstruction.</a> Stem Cells Int. , 2636454 (2016).</li><li>Calcagni, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+novel+treatment+of+SVF-enriched+fat+grafting+for+painful+end-neuromas+of+superficial+radial+nerve.">The novel treatment of SVF-enriched fat grafting for painful end-neuromas of superficial radial nerve.</a> Microsurgery. , (2016).</li><li>Hoying, J. B., Boswell, C. A., Williams, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angiogenic+potential+of+microvessel+fragments+established+in+three-dimensional+collagen+gels.">Angiogenic potential of microvessel fragments established in three-dimensional collagen gels.</a> In Vitro Cell Dev Biol Anim. 32 (7), 409-419 (1996).</li><li>Kirkpatrick, N. D., Andreou, S., Hoying, J. B., Utzinger, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+imaging+of+collagen+remodeling+during+angiogenesis.">Live imaging of collagen remodeling during angiogenesis.</a> Am J Physiol Heart Circ Physiol. 292 (6), H3198-H3206 (2007).</li></ol>

In this study we present a well-established protocol for the isolation of ad-MVF. Obtaining ad-MVF from murine adipose tissue is a straightforward procedure with a few critical steps. Mice exhibit different subcutaneous and intraabdominal fat deposits. As previously described for rats, the most suitable fat source for the isolation of ad-MVF are the epididymal fat pads due to their size, homogeneous structure and minimal contamination with larger blood vessels11,12</su...

Tissue engineering focuses on the fabrication of tissue and organ substitutes that maintain, restore or augment the function of inoperable in vivo counterparts1,2. The fate of engineered tissue constructs crucially depends on an adequate vascularization3. Microvascular networks within these constructs should be hierarchically organized with arterioles, capillaries, and venules to allow efficient blood perfusion after inosculation to the recipient&#39;s vasculature4. The generation of such networks is among the key challenges in tissue engineering. For this purpose, a broad spectrum of experimental vascularization strategies has been introduced over the last two decades5,6.
Angiogenic approaches stimulate the ingrowth of recipient microvessels into engineered tissues by means of structural or physicochemical scaffold modification, such as the incorporation of growth factors7. However, for the vascularization of large three-dimensional constructs, angiogenesis-dependent strategies are markedly limited by slow growth rates of developing microvessels8.
In contrast, the concept of prevascularization aims for the generation of functional microvascular networks within tissue constructs prior to their implantation9. Conventional prevascularization involves the co-culture of vessel-forming cells, such as endothelial cells, mural cells or stem cells10, within scaffolds. After microvascular network formation, the prevascularized constructs can then be implanted into tissue defects. Noteworthy, this prevascularization approach is difficult to apply in a clinical setting, because it is based on complex and time-consuming in vitro procedures, which are restricted by major regulatory hurdles9. Accordingly, there is still a need for the development of novel prevascularization strategies that are more suitable for a broad clinical application.
Such a prevascularization strategy may be the application of adipose tissue-derived microvascular fragments (ad-MVF). ad-MVF represent potent vascularization units that can be harvested in large amounts from the fat tissue of rats11,12 and mice13. They consist of arteriolar, capillary, and venular vessel segments, which exhibit a physiological microvessel morphology with a lumen and stabilizing perivascular cells14,15. This unique feature allows the immediate implantation of ad-MVF-seeded scaffolds into tissue defects without precultivation. There, the ad-MVF rapidly reassemble into functional microvascular networks. Furthermore, ad-MVF represent a rich source of mesenchymal stem cells16, which may additionally contribute to their striking regenerative capacity. Accordingly, ad-MVF are increasingly used in different fields of tissue engineering14,15,17,18,19,20,21.
The isolation of ad-MVF has originally been established in rats11,12. Herein, we describe a protocol, which allows the standardized isolation of murine ad-MVF from epididymal fat pads. This may provide further insights into molecular mechanisms underlying ad-MVF function by using transgenic mouse models.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1.5-mL conical microcentrifuge tube</td>
			<td>VWR, Kelsterbach, Germany</td>
			<td>700-5239</td>
			<td></td>
		</tr>
		<tr>
			<td>100-&#181;L precision pipette</td>
			<td>Eppendorf, Hamburg, Germany</td>
			<td>4920000059</td>
			<td></td>
		</tr>
		<tr>
			<td>10-mL measuring pipette</td>
			<td>Costar, Corning Inc., New York, USA</td>
			<td>4488</td>
			<td></td>
		</tr>
		<tr>
			<td>14-mL PP tubes</td>
			<td>Greiner bio-one, Frickenhausen, Germany</td>
			<td>187261</td>
			<td></td>
		</tr>
		<tr>
			<td>1-mL precision pipette</td>
			<td>Eppendorf, Hamburg, Germany</td>
			<td>4920000083</td>
			<td></td>
		</tr>
		<tr>
			<td>500-&#181;m filter (pluriStrainer 500 &#181;m)</td>
			<td>HISS Diagnostics, Freiburg, Germany</td>
			<td>43-50500-03</td>
			<td></td>
		</tr>
		<tr>
			<td>50-mL conical centrifuge tube</td>
			<td>Greiner bio-one, Frickenhausen, Germany</td>
			<td>227261</td>
			<td></td>
		</tr>
		<tr>
			<td>50-mL Erlenmeyer flask</td>
			<td>VWR, Kelsterbach, Germany</td>
			<td>214-0211</td>
			<td></td>
		</tr>
		<tr>
			<td>96-well plate</td>
			<td>Greiner bio-one, Frickenhausen, Germany</td>
			<td>65518</td>
			<td></td>
		</tr>
		<tr>
			<td>cell detachment solution (Accutase)</td>
			<td>eBioscience, San Diego, CA USA</td>
			<td>00-4555-56</td>
			<td></td>
		</tr>
		<tr>
			<td>C57BL/6 mice</td>
			<td>Charles River, Cologne, Germany</td>
			<td>027</td>
			<td></td>
		</tr>
		<tr>
			<td>C57BL/6-Tg(CAG-EGFP)1Osb/J mice</td>
			<td>The Jackson Laboratory, Bar Harbor, USA</td>
			<td>003291</td>
			<td></td>
		</tr>
		<tr>
			<td>CD117-FITC</td>
			<td>BD Biosciences, Heidelberg, Germany</td>
			<td>553373</td>
			<td></td>
		</tr>
		<tr>
			<td>CD31-PE</td>
			<td>BD Biosciences, Heidelberg, Germany</td>
			<td>553354</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase NB4G&#160;</td>
			<td>Serva Electrophoresis GmbH, Heidelberg, Germany</td>
			<td>17465.02</td>
			<td>Lot tested by manufacturer for enzymatic activity</td>
		</tr>
		<tr>
			<td>Dissection scissors</td>
			<td>Braun Aesculap AG &#38;CoKG, Melsungen, Germany</td>
			<td>BC 601</td>
			<td></td>
		</tr>
		<tr>
			<td>DNA-binding dye (Bisbenzimide H33342)</td>
			<td>Sigma-Aldrich, Taufkirchen, Germany</td>
			<td>B2261</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s modified Eagle medium (DMEM)&#160;</td>
			<td>PAN Biotech, Rickenbach, Germany</td>
			<td>P04-03600</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal calf serum (FCS)</td>
			<td>Biochrom GmbH, Berlin, Germany</td>
			<td>S0615</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine forceps</td>
			<td>S&#38;T AG, Neuhausen, Switzerland</td>
			<td>FRS-15 RM-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine scissors</td>
			<td>World Precision Instrumets, Sarasota, FL, USA</td>
			<td>503261</td>
			<td></td>
		</tr>
		<tr>
			<td>Dermal skin substitute (Integra)</td>
			<td>Integra Life Sciences, Sain Priest, France</td>
			<td>62021</td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamine&#160;</td>
			<td>Serumwerk Bernburg AG, Bernburg, Germany</td>
			<td>7005294</td>
			<td></td>
		</tr>
		<tr>
			<td>M-IgG2akAL488&#160;&#160;</td>
			<td>eBioscience, San Diego, CA USA</td>
			<td>53-4724-80</td>
			<td></td>
		</tr>
		<tr>
			<td>Octeniderm (disinfecting solution)</td>
			<td>Sch&#252;lke &#38; Mayer, Norderstedt, Germany</td>
			<td>118211</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Biochrom, Berlin, Germany</td>
			<td>A2213</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td>Greiner bio-one, Frickenhausen, Germany</td>
			<td>664160</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-buffered saline (PBS)</td>
			<td>Lonza Group, Basel, Switzerland</td>
			<td>17-516F</td>
			<td></td>
		</tr>
		<tr>
			<td>pluriStrainer 20-&#181;m (20 &#181;m filter)</td>
			<td>HISS Diagnostics, Freiburg, Germany</td>
			<td>43-50020-03</td>
			<td></td>
		</tr>
		<tr>
			<td>Rat-IgG2akFITC</td>
			<td>BD Biosciences, Heidelberg, Germany</td>
			<td>553988</td>
			<td></td>
		</tr>
		<tr>
			<td>Rat-IgG2akPE</td>
			<td>BD Biosciences, Heidelberg, Germany</td>
			<td>553930</td>
			<td></td>
		</tr>
		<tr>
			<td>Small preparation scissors</td>
			<td>S&#38;T AG, Neuhausen, Switzerland</td>
			<td>SDC-15 R-8S</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical forceps</td>
			<td>Braun Aesculap AG &#38;CoKG, Melsungen, Germany</td>
			<td>BD510R</td>
			<td></td>
		</tr>
		<tr>
			<td>Tape (Heftpflaster Seide) 1.25 cm</td>
			<td>Fink &#38; Walter GmbH, Mechweiler, Germany</td>
			<td>1671801</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylazine&#160;</td>
			<td>Bayer Vital GmbH, Leverkusen, Germany</td>
			<td>1320422</td>
			<td></td>
		</tr>
		<tr>
			<td>&#945;-SMA-AL488</td>
			<td>eBioscience, San Diego, CA USA</td>
			<td>53-9760-82</td>
			<td>Intracellular labeling additionally requires Cytofix/Cytoperm (BD Biosciences, Heidelberg, Germany; #554722)</td>
		</tr>
	</tbody>
</table>

isolation of murine adipose tissue-derived microvascular fragments as vascularization units for tissue engineering

A functional microvascular network is of pivotal importance for the survival and integration of engineered tissue constructs. For this purpose, several angiogenic and prevascularization strategies have been established. However, most cell-based approaches include time-consuming in vitro steps for the formation of a microvascular network. Hence, they are not suitable for intraoperative one-step procedures. Adipose tissue-derived microvascular fragments (ad-MVF) represent promising vascularization units. They can be easily isolated from fat tissue and exhibit a functional microvessel morphology. Moreover, they rapidly reassemble into new microvascular networks after in vivo implantation. In addition, ad-MVF have been shown to induce lymphangiogenesis. Finally, they are a rich source of mesenchymal stem cells, which may further contribute to their high vascularization potential. In previous studies we have demonstrated the remarkable vascularization capacity of ad-MVF in engineered bone and skin substitutes. In the present study, we report on a standardized protocol for the enzymatic isolation of ad-MVF from murine fat tissue.

In the present study we performed six ad-MVF isolation procedures with fat tissue from 7- to 12-month-old male wild-type C57BL/6 mice (mean body weight: 35 &#177; 1 g). Figure 1 illustrates the harvesting of murine epididymal fat pads with subsequent mechanical and enzymatic ad-MVF isolation. The time required for the harvesting of fat was 30 min and for the isolation of ad-MVF was 120 min. In total, the procedure took 150 min.
<p class="jove_content" fo:keep-together...

Watch this Scientific Journal Video about Isolation of Murine Adipose Tissue-derived Microvascular Fragments as Vascularization Units for Tissue Engineering at JoVE.com

Isolation of Murine Adipose Tissue-derived Microvascular Fragments as Vascularization Units for Tissue Engineering

We present a protocol to isolate adipose tissue-derived microvascular fragments that represent promising vascularization units. They can be rapidly isolated, do not require in vitro processing and, thus, may be used for one-step prevascularization in different fields of tissue engineering.

A functional microvascular network is of pivotal importance for the survival and integration of engineered tissue constructs. For this purpose, several ...

The overall goal of this procedure is to isolate microvascular fragments from murine adipose tissue for the generation of vascularization units for tissue engineering. This method can help answer key questions in the field of tissue engineering about the in vivo vascularization of tissue substitues. An advantage of this technique is that it yields fully functional microvascular segments without complex in vitro processing that can be seeded onto scaffolds and implanted into tissue defects.This method can also be applied to other systems such as in vitro angiogenesis assays to unravel molecular mechanisms underlying microvascular network formation and remodeling. Begin by placing an anesthetized male wild type C57 black six mouse in the supine position under a surgical stereomicroscope and confirm a lack of response to toe pinch. Immobilize the paws with tape and disinfect the abdomen.Next, use dissecting scissors to separate the abdominal layer from the underlying muscle tissue and make a midline laparotomy. Laterally unfold the flaps of the abdominal wall and bilaterally identify the testes, epididymus and the epididymal fat pads. Then use small preparation scissors and fine forceps to harvest the fat pads, taking care not to collect any epididymal tissue and place the fat pads into a petri dish containing 15 ml of 37 degrees celsius DMEM.In a laminar flow hood, wash the fat pads in three separate petri dishes containing 15 ml of PBS and place the washed fat into an empty 14 ml polypropylene tube. Use a tube scale to determine the volume of harvested fat. Then use fine scissors to mechanically mince the fat tissue.When a homogenous tissue suspension is obtained, use a 10 mL measuring pipet to transfer the minced tissue with two volumes of collaginase NB 4G into a 50 mL erlenmeyer flask containing a 25 millimeter stir bar. Place the flask in a cell culture incubator for 10 minutes under vigorous stirring. Then, observe 10 mcL of the digested tissue under a microscope.The most difficult step in this isolation procedure is identifying the appropriate time to stop the digestion. Digesting the fat pads for too long will result in a single cell suspension without any microvascular fragments. If the digestate contains free adipose tissue derived microvascular fragments next to single cells, neutralize the enzyme with two volumes of PBS supplemented with 20%FCS and transfer the cell vessel suspension into new polypropylene tubes.Incubate the solution for five minutes at 37 degrees celsius to separate the microvascular fragments from the remaining fat by gravity. Then, use a one mL precision pipet to carefully remove one mL of the main fat supernatent followed by the use of a 100 mcL precision pipet to remove the rest of the supernatent until the suspension appears to be fat free. When all of the fat has been removed, use a 10 mL measuring pipet to filter the cell vessel suspension through a 50 micron strainer over a 50 mL conical tube and transfer the filtered suspension into a new 14 mL polypropylene tube for each individual microvascular fragment isolate.Collect the microvascular fragment pellets by centrifugation and remove all but the last one mL of supernatent from each tube. Resuspend the pellets in the remaining supernatents. Then, transfer each suspension into individual 1.5 mL conical microcentrifuge tubes and pellet the microvascular fragments again for resuspension in the appropriate final volume of PBS and 20%FCS for the planned downstream analysis.Here, the length distribution of freshly isolated microvascular fragments from six, seven to twelve month old wild type C57 black six mice is shown, with a mean average length of approximately 42 micrometers observed. As this representative cell vessel suspension smear demonstrates, large, medium and small microvascular fragments as well as single cells are observed when the fat tissue has been sufficiently digested. Higher magnification reveals that the microvascular fragments exhibit a mature microvessel morphology with hierarchical microvessel segments.Characterization of the microvascular fragments by flow cytometry indicates that they contain CD31 positive endothelial cells, alpha smooth muscle acton positive paravascular cells and CD117 positive mesenchymal stem cells, marker expressing cells. After seeding on a dermal skin substitute, larger microvascular fragments are mainly localized on the implant's surface with some capillary vessel segments detected within the implant cores. Immunohystochemical staining of the seeded microvascular fragments further reveals physiological microvessel configurations with arteriolar, venular and capillary like fragments.Once mastered, this technique can be completed in two hours if performed properly. After watching this video, you should have a good understanding of how to isolate microvascular fragments from murine adipose tissue as vascularization units for tissue engineering.

isolation-murine-adipose-tissue-derived-microvascular-fragments-as

Research

JoVE Journal

Bioengineering

Elastomeric PGS Scaffolds in Arterial Tissue Engineering

Cardiovascular disease is one of the leading cause of mortality in the US and especially, coronary artery disease increases with an aging population and increasing obesity1. Currently, bypass surgery using autologous vessels, allografts, and synthetic grafts are known as a commonly used for arterial substitutes2. However, these grafts have limited applications when an inner diameter of arteries is less than 6 mm due to low availability, thrombotic complications, compliance mismatch, and late intimal hyperplasia3,4. To overcome these limitations, tissue engineering has been successfully applied as a promising alternative to develop small-diameter arterial constructs that are nonthrombogenic, robust, and compliant. Several previous studies have developed small-diameter arterial constructs with tri-lamellar structure, excellent mechanical properties and burst pressure comparable to native arteries5,6. While high tensile strength and burst pressure by increasing collagen production from a rigid material or cell sheet scaffold, these constructs still had low elastin production and compliance, which is a major problem to cause graft failure after implantation. Considering these issues, we hypothesized that an elastometric biomaterial combined with mechanical conditioning would provide elasticity and conduct mechanical signals more efficiently to vascular cells, which increase extracellular matrix production and support cellular orientation.
The objective of this report is to introduce a fabrication technique of porous tubular scaffolds and a dynamic mechanical conditioning for applying them to arterial tissue engineering. We used a biodegradable elastomer, poly (glycerol sebacate) (PGS)7 for fabricating porous tubular scaffolds from the salt fusion method. Adult primary baboon smooth muscle cells (SMCs) were seeded on the lumen of scaffolds, which cultured in our designed pulsatile flow bioreactor for 3 weeks. PGS scaffolds had consistent thickness and randomly distributed macro- and micro-pores. Mechanical conditioning from pulsatile flow bioreactor supported SMC orientation and enhanced ECM production in scaffolds. These results suggest that elastomeric scaffolds and mechanical conditioning of bioreactor culture may be a promising method for arterial tissue engineering.

Elastomeric PGS scaffolds with vascular smooth muscle cells cultured in a pulsatile flow bioreactor may lead to promising small-diameter arterial constructs with native ECM production in a relatively short culture period.

Cardiovascular disease is one of the leading cause of mortality in the US and especially, coronary artery disease increases with an aging population and ...

Postproduction Processing of Electrospun Fibres for Tissue Engineering

Electrospinning is a commonly used and versatile method to produce scaffolds (often biodegradable) for 3D tissue engineering.1, 2, 3 Many tissues in vivo undergo biaxial distension to varying extents such as skin, bladder, pelvic floor and even the hard palate as children grow. In producing scaffolds for these purposes there is a need to develop scaffolds of appropriate biomechanical properties (whether achieved without or with cells) and which are sterile for clinical use. The focus of this paper is not how to establish basic electrospinning parameters (as there is extensive literature on electrospinning) but on how to modify spun scaffolds post production to make them fit for tissue engineering purposes - here thickness, mechanical properties and sterilisation (required for clinical use) are considered and we also describe how cells can be cultured on scaffolds and subjected to biaxial strain to condition them for specific applications.
Electrospinning tends to produce thin sheets; as the electrospinning collector becomes coated with insulating fibres it becomes a poor conductor such that fibres no longer deposit on it. Hence we describe approaches to produce thicker structures by heat or vapour annealing increasing the strength of scaffolds but not necessarily the elasticity. Sequential spinning of scaffolds of different polymers to achieve complex scaffolds is also described. Sterilisation methodologies can adversely affect strength and elasticity of scaffolds. We compare three methods for their effects on the biomechanical properties on electrospun scaffolds of poly lactic-co-glycolic acid (PLGA).
Imaging of cells on scaffolds and assessment of production of extracellular matrix (ECM) proteins by cells on scaffolds is described. Culturing cells on scaffolds in vitro can improve scaffold strength and elasticity but the tissue engineering literature shows that cells often fail to produce appropriate ECM when cultured under static conditions. There are few commercial systems available that allow one to culture cells on scaffolds under dynamic conditioning regimes - one example is the Bose Electroforce 3100 which can be used to exert a conditioning programme on cells in scaffolds held using mechanical grips within a media filled chamber.4 An approach to a budget cell culture bioreactor for controlled distortion in 2 dimensions is described. We show that cells can be induced to produce elastin under these conditions. Finally assessment of the biomechanical properties of processed scaffolds cultured with or without cells is described.

Electrospun scaffolds can be processed post production for tissue engineering applications. Here we describe methods for spinning complex scaffolds (by consecutive spinning), for making thicker scaffolds (by multi-layering using heat or vapour annealing), for achieving sterility (aseptic production or sterilisation post production) and for achieving appropriate biomechanical properties.

Electrospinning is a commonly used and versatile method to produce  scaffolds (often biodegradable) for 3D tissue engineering.1, 2, 3 Many tissues in vivo ...

Engineering Skeletal Muscle Tissues from Murine Myoblast Progenitor Cells and Application of Electrical Stimulation

Engineered muscle tissues can be used for several different purposes, which include the production of tissues for use as a disease model in vitro, e.g. to study pressure ulcers, for regenerative medicine and as a meat alternative 1. The first reported 3D muscle constructs have been made many years ago and pioneers in the field are Vandenburgh and colleagues 2,3. Advances made in muscle tissue engineering are not only the result from the vast gain in knowledge of biochemical factors, stem cells and progenitor cells, but are in particular based on insights gained by researchers that physical factors play essential roles in the control of cell behavior and tissue development. State-of-the-art engineered muscle constructs currently consist of cell-populated hydrogel constructs. In our lab these generally consist of murine myoblast progenitor cells, isolated from murine hind limb muscles or a murine myoblast cell line C2C12, mixed with a mixture of collagen/Matrigel and plated between two anchoring points, mimicking the muscle ligaments. Other cells may be considered as well, e.g. alternative cell lines such as L6 rat myoblasts 4, neonatal muscle derived progenitor cells 5, cells derived from adult muscle tissues from other species such as human 6 or even induced pluripotent stem cells (iPS cells) 7. Cell contractility causes alignment of the cells along the long axis of the construct 8,9 and differentiation of the muscle progenitor cells after approximately one week of culture. Moreover, the application of electrical stimulation can enhance the process of differentiation to some extent 8. Because of its limited size (8 x 2 x 0.5 mm) the complete tissue can be analyzed using confocal microscopy to monitor e.g. viability, differentiation and cell alignment. Depending on the specific application the requirements for the engineered muscle tissue will vary; e.g. use for regenerative medicine requires the up scaling of tissue size and vascularization, while to serve as a meat alternative translation to other species is necessary.

Engineered muscle tissue has great potential in regenerative medicine, as disease model and also as an alternative source for meat. Here we describe the engineering of a muscle construct, in this case from mouse myoblast progenitor cells, and the stimulation by electrical pulses.

Engineered muscle tissues can be used for several different purposes, which include the production of tissues for use as a disease model in vitro, e.g. to ...

Tissue Engineering of the Intestine in a Murine Model

Tissue-engineered small intestine (TESI) has successfully been used to rescue Lewis rats after massive small bowel resection, resulting in return to preoperative weights within 40 days.1 In humans, massive small bowel resection can result in short bowel syndrome, a functional malabsorptive state that confers significant morbidity, mortality, and healthcare costs including parenteral nutrition dependence, liver failure and cirrhosis, and the need for multivisceral organ transplantation.2 In this paper, we describe and document our protocol for creating tissue-engineered intestine in a mouse model with a multicellular organoid units-on-scaffold approach. Organoid units are multicellular aggregates derived from the intestine that contain both mucosal and mesenchymal elements,3 the relationship between which preserves the intestinal stem cell niche.4 In ongoing and future research, the transition of our technique into the mouse will allow for investigation of the processes involved during TESI formation by utilizing the transgenic tools available in this species.5The availability of immunocompromised mouse strains will also permit us to apply the technique to human intestinal tissue and optimize the formation of human TESI as a mouse xenograft before its transition into humans. Our method employs good manufacturing practice (GMP) reagents and materials that have already been approved for use in human patients, and therefore offers a significant advantage over approaches that rely upon decellularized animal tissues. The ultimate goal of this method is its translation to humans as a regenerative medicine therapeutic strategy for short bowel syndrome.

This article and the accompanying video present our protocol for generating tissue-engineered intestine in the mouse, using an organoid units-on-scaffold approach.

Tissue-engineered small intestine (TESI) has successfully been used to rescue Lewis rats after massive small bowel resection, resulting in return to ...

Capillary Force Lithography for Cardiac Tissue Engineering

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical discoveries with the aims of developing functional tissues for cardiac regeneration as well as in vitro screening assays. However, the ability to create high-fidelity models of heart tissue has proven difficult. The heart&#8217;s extracellular matrix (ECM) is a complex structure consisting of both biochemical and biomechanical signals ranging from the micro- to the nanometer scale2. Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering3-5.
A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling2. Unfortunately, few methods have been able to mimic the organization of ECM fibers down to the nanometer scale. Recent advancements in nanofabrication techniques, however, have enabled the design and fabrication of scalable scaffolds that mimic the in vivo structural and substrate stiffness cues of the ECM in the heart6-9.
Here we present the development of two reproducible, cost-effective, and scalable nanopatterning processes for the functional alignment of cardiac cells using the biocompatible polymer poly(lactide-co-glycolide) (PLGA)8 and a polyurethane (PU) based polymer. These anisotropically nanofabricated substrata (ANFS) mimic the underlying ECM of well-organized, aligned tissues and can be used to investigate the role of nanotopography on cell morphology and function10-14.
Using a nanopatterned (NP) silicon master as a template, a polyurethane acrylate (PUA) mold is fabricated. This PUA mold is then used to pattern the PU or PLGA hydrogel via UV-assisted or solvent-mediated capillary force lithography (CFL), respectively15,16. Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip and the PUA mold is placed on top. For UV-assisted CFL, the PU is then exposed to UV radiation (&#955; = 250-400 nm) for curing. For solvent-mediated CFL, the PLGA is embossed using heat (120 &#176;C) and pressure (100 kPa). After curing, the PUA mold is peeled off, leaving behind an ANFS for cell culture. Primary cells, such as neonatal rat ventricular myocytes, as well as human pluripotent stem cell-derived cardiomyocytes, can be maintained on the ANFS2.

In this protocol, we demonstrate the fabrication of biomimetic cardiac cell culture substrata made from two distinct polymeric materials using capillary force lithography. The described methods provide a scalable, cost-effective technique to engineer the structure and function of macroscopic cardiac tissues for in vitro and in vivo applications.

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical ...

Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled.
The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The &#8220;static bioreactor&#8221; provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues.

In this work, we present a technique for the rapid fabrication of living vascular tissues by direct culturing of collagen, smooth muscle cells and endothelial cells. In addition, a new protocol for the mechanical characterization of engineered vascular tissues is described.

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. ...

Preparation of Thermoresponsive Nanostructured Surfaces for Tissue Engineering

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the Langmuir-Schaefer method. Amphiphilic block copolymers composed of polystyrene and PIPAAm (St-IPAAms) were synthesized by reversible addition-fragmentation chain transfer (RAFT) radical polymerization. A chloroform solution of St-IPAAm molecules was gently dropped into a Langmuir-trough apparatus, and both barriers of the apparatus were moved horizontally to compress the film to regulate its density. Then, the St-IPAAm Langmuir film was horizontally transferred onto a hydrophobically modified glass substrate by a surface-fixed device. Atomic force microscopy images clearly revealed nanoscale sea-island structures on the surface. The strength, rate, and quality of cell adhesion and detachment on the prepared surface were modulated by changes in temperature across the lower critical solution temperature range of PIPAAm molecules. In addition, a two-dimensional cell structure (cell sheet) was successfully recovered on the optimized surfaces. These unique PIPAAm surfaces may be useful for controlling the strength of cell adhesion and detachment.

Nanoscaled sea-island surfaces composed of thermoresponsive block copolymers were fabricated by the Langmuir-Schaefer method for controlling spontaneous cell adhesion and detachment. Both the preparation of the surface and the adhesion and detachment of cells on the surface were visualized.

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the ...

Tissue Engineering by Intrinsic Vascularization in an In Vivo Tissue Engineering Chamber

In reconstructive surgery, there is a clinical need for an alternative to the current methods of autologous reconstruction which are complex, costly and trade one defect for another. Tissue engineering holds the promise to address this increasing demand. However, most tissue engineering strategies fail to generate stable and functional tissue substitutes because of poor vascularization. This paper focuses on an in vivo tissue engineering chamber model of intrinsic vascularization where a perfused artery and a vein either as an arteriovenous loop or a flow-through pedicle configuration is directed inside a protected hollow chamber. In this chamber-based system angiogenic sprouting occurs from the arteriovenous vessels and this system attracts ischemic and inflammatory driven endogenous cell migration which gradually fills the chamber space with fibro-vascular tissue. Exogenous cell/matrix implantation at the time of chamber construction enhances cell survival and determines specificity of the engineered tissues which develop. Our studies have shown that this chamber model can successfully generate different tissues such as fat, cardiac muscle, liver and others. However, modifications and refinements are required to ensure target tissue formation is consistent and reproducible. This article describes a standardized protocol for the fabrication of two different vascularized tissue engineering chamber models in vivo.

Tissue Engineering by Intrinsic Vascularization in an In Vivo Tissue Engineering Chamber

This is a guideline for constructing in vivo vascularized tissue using a microsurgical arteriovenous loop or a flow-through pedicle configuration inside a tissue engineering chamber. The vascularized tissues generated can be employed for organ regeneration and replacement of tissue defects, as well as for drug testing and disease modeling.

In reconstructive surgery, there is a clinical need for an alternative to the current methods of autologous reconstruction which are complex, costly and ...

A Microfluidic Platform for High-throughput Single-cell Isolation and Culture

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet high-throughput, method to perform single-cell culture experiments. Here, we report a microfluidic chip-based strategy for high-efficiency single-cell isolation (~77%) and demonstrate its capability of performing long-term single-cell culture (up to 7 d) and cellular heterogeneity analysis using clonogenic assay. These applications were demonstrated with KT98 mouse neural stem cells, and A549 and MDA-MB-435 human cancer cells. High single-cell isolation efficiency and long-term culture capability are achieved by using different sizes of microwells on the top and bottom of the microfluidic channel. The small microwell array is designed for precisely isolating single-cells, and the large microwell array is used for single-cell clonal culture in the microfluidic chip. This microfluidic platform constitutes an attractive approach for single-cell culture applications, due to its flexibility of adjustable cell culture spaces for different culture strategies, without decreasing isolation efficiency.

Here, we present a protocol for isolating and culturing single cells with a microfluidic platform, which utilizes a new microwell design concept to allow for high-efficiency single cell isolation and long-term clonal culture.

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet ...

Two Methods for Decellularization of Plant Tissues for Tissue Engineering Applications

The autologous, synthetic, and animal-derived grafts currently used as scaffolds for tissue replacement have limitations due to low availability, poor biocompatibility, and cost. Plant tissues have favorable characteristics that make them uniquely suited for use as scaffolds, such as high surface area, excellent water transport and retention, interconnected porosity, preexisting vascular networks, and a wide range of mechanical properties. Two successful methods of plant decellularization for tissue engineering applications are described here. The first method is based on detergent baths to remove cellular matter, which is similar to previously established methods used to clear mammalian tissues. The second is a detergent-free method adapted from a protocol that isolates leaf vasculature and involves the use of a heated bleach and salt bath to clear the leaves and stems. Both methods yield scaffolds with comparable mechanical properties and low cellular metabolic impact, thus allowing the user to select the protocol which better suits their intended application.

Here we present, and contrast two protocols used to decellularize plant tissues: a detergent-based approach and a detergent-free approach. Both methods leave behind the extracellular matrix of the plant tissues used, which can then be utilized as scaffolds for tissue engineering applications.

The autologous, synthetic, and animal-derived grafts currently used as scaffolds for tissue replacement have limitations due to low availability, poor ...