Name: microdissection of primary renal tissue segments and incorporation with novel scaffold-free construct technology
Uploaded: 2018-03-27T13:30:00
Description: Watch this Scientific Journal Video about Microdissection of Primary Renal Tissue Segments and Incorporation with Novel Scaffold-free Construct Technology at JoVE.com

NIH Institutional Postdoctoral Training Grant, NIH-HL-007260

All animal surgical procedures described below were approved by the Institutional Animal Care and Use Committee (IACUC) at the Medical University of South Carolina prior to any animal surgeries or use of any animal tissues.
1. Murine Nephrectomy
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	<li>Don a surgical mask and bouffant cap to minimize the risk of contamination. Maintain sterility during set-up of the&#160;surgical area.
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		<li>Place non-fenestrated surgical drapes on the operating table.</li>
		<li>Open the pack of au...

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	<li>Jha, V., 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=Chronic+kidney+disease:+global+dimension+and+perspectives.">Chronic kidney disease: global dimension and perspectives.</a> Lancet. 382 (9888), 260-272 (2013).</li><li>2016 USRDS Annual Data Report: Epidemiology of Kidney Disease in the United States. U.S.R.D Available from: <a target="_blank" href="https://www.usrds.org/2016/download/v2_ESRD_16.pdf">https://www.usrds.org/2016/download/v2_ESRD_16.pdf</a> (2016)</li><li>Hart, A., 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=OPTN/SRTR+2015+Annual+Data+Report:+Kidney.">OPTN/SRTR 2015 Annual Data Report: Kidney.</a> American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons. 17, 21-116 (2017).</li><li>de Vries, E. F., Rabelink, T. J., van den Hout, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+the+Cost-Effectiveness+of+Delaying+End-Stage+Renal+Disease.">Modelling the Cost-Effectiveness of Delaying End-Stage Renal Disease.</a> Nephron. 133 (2), 89-97 (2016).</li><li>Lefebvre, P., Duh, M. S., Mody, S. H., Bookhart, B., Piech, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+economic+impact+of+epoetin+alfa+therapy+on+delaying+time+to+dialysis+in+elderly+patients+with+chronic+kidney+disease.">The economic impact of epoetin alfa therapy on delaying time to dialysis in elderly patients with chronic kidney disease.</a> Disease management : DM. 10 (1), 37-45 (2007).</li><li>Mennini, F. S., Russo, S., Marcellusi, A., Quintaliani, G., Fouque, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Economic+effects+of+treatment+of+chronic+kidney+disease+with+low-protein+diet.">Economic effects of treatment of chronic kidney disease with low-protein diet.</a> Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation. 24 (5), 313-321 (2014).</li><li>Moon, K. H., Ko, I. K., Yoo, J. J., Atala, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kidney+diseases+and+tissue+engineering.">Kidney diseases and tissue engineering.</a> Methods. 99, 112-119 (2016).</li><li>Wobma, H., Vunjak-Novakovic, G. <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+and+Regenerative+Medicine+2015:+A+Year+in+Review.">Tissue Engineering and Regenerative Medicine 2015: A Year in Review.</a> Tissue engineering. Part B, Reviews. 22 (2), 101-113 (2016).</li><li>Langer, R., Vacanti, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+tissue+engineering.">Advances in tissue engineering.</a> Journal of pediatric surgery. 51 (1), 8-12 (2016).</li><li>Jakab, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+engineering+by+self-assembly+and+bio-printing+of+living+cells.">Tissue engineering by self-assembly and bio-printing of living cells.</a> Biofabrication. 2 (2), 022001 (2010).</li><li>Fisher, M. B., Mauck, R. L. <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+and+regenerative+medicine:+recent+innovations+and+the+transition+to+translation.">Tissue engineering and regenerative medicine: recent innovations and the transition to translation.</a> Tissue engineering. Part B, Reviews. 19 (1), 1-13 (2013).</li><li>Stewart, D. E., Garcia, V. C., Rosendale, J. D., Klassen, D. K., Carrico, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosing+the+Decades-Long+Rise+in+the+Deceased+Donor+Kidney+Discard+Rate+in+the+United+States.">Diagnosing the Decades-Long Rise in the Deceased Donor Kidney Discard Rate in the United States.</a> Transplantation. 101 (3), 575-587 (2017).</li><li>Mohan, 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=The+weekend+effect+alters+the+procurement+and+discard+rates+of+deceased+donor+kidneys+in+the+United+States.">The weekend effect alters the procurement and discard rates of deceased donor kidneys in the United States.</a> Kidney international. 90 (1), 157-163 (2016).</li><li>Orlando, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discarded+human+kidneys+as+a+source+of+ECM+scaffold+for+kidney+regeneration+technologies.">Discarded human kidneys as a source of ECM scaffold for kidney regeneration technologies.</a> Biomaterials. 34 (24), 5915-5925 (2013).</li><li>Katari, R., 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=Renal+bioengineering+with+scaffolds+generated+from+human+kidneys.">Renal bioengineering with scaffolds generated from human kidneys.</a> Nephron. Experimental nephrology. 126 (2), 119 (2014).</li><li>Kim, S. S., Park, H. J., Han, J., Choi, C. Y., Kim, B. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Renal+tissue+reconstitution+by+the+implantation+of+renal+segments+on+biodegradable+polymer+scaffolds.">Renal tissue reconstitution by the implantation of renal segments on biodegradable polymer scaffolds.</a> Biotechnology letters. 25 (18), 1505-1508 (2003).</li><li>Guimaraes-Souza, N. K., Yamaleyeva, L. M., AbouShwareb, T., Atala, A., Yoo, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+reconstitution+of+human+kidney+structures+for+renal+cell+therapy.">In vitro reconstitution of human kidney structures for renal cell therapy.</a> Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 27 (8), 3082-3090 (2012).</li><li>Kelley, R., 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=Tubular+cell-enriched+subpopulation+of+primary+renal+cells+improves+survival+and+augments+kidney+function+in+rodent+model+of+chronic+kidney+disease.">Tubular cell-enriched subpopulation of primary renal cells improves survival and augments kidney function in rodent model of chronic kidney disease.</a> American journal of physiology. Renal physiology. 299 (5), 1026-1039 (2010).</li><li>Czajka, C. A., Drake, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-assembly+of+prevascular+tissues+from+endothelial+and+fibroblast+cells+under+scaffold-free,+nonadherent+conditions.">Self-assembly of prevascular tissues from endothelial and fibroblast cells under scaffold-free, nonadherent conditions.</a> Tissue engineering. Part A. 21 (1-2), 277-287 (2015).</li><li>Rhett, J. M., Wang, H., Bainbridge, H., Song, L., Yost, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Connexin-Based+Therapeutics+and+Tissue+Engineering+Approaches+to+the+Amelioration+of+Chronic+Pancreatitis+and+Type+I+Diabetes:+Construction+and+Characterization+of+a+Novel+Prevascularized+Bioartificial+Pancreas.">Connexin-Based Therapeutics and Tissue Engineering Approaches to the Amelioration of Chronic Pancreatitis and Type I Diabetes: Construction and Characterization of a Novel Prevascularized Bioartificial Pancreas.</a> Journal of diabetes research. 2016, 7262680 (2016).</li><li>Al-Awqati, Q., Oliver, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+cells+in+the+kidney.">Stem cells in the kidney.</a> Kidney international. 61 (2), 387-395 (2002).</li><li>Aboushwareb, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Erythropoietin+producing+cells+for+potential+cell+therapy.">Erythropoietin producing cells for potential cell therapy.</a> World journal of urology. 26 (4), 295-300 (2008).</li></ol>

Methods used to engineer living renal tissue constructs vary widely with regard to both the type of cells and biomaterials utilized, and in many cases, are outdated or not well-characterized in the literature7. While many are using stem cell approaches or recapitulating individual components of the renal architecture in isolation, the prospect of artificially recreating an entire organ with over 26 different differentiated cell types from cellular suspensions is overwhelming to consider<sup class=...

Chronic kidney disease (CKD) is one of the current major public health challenges worldwide1. The prevalence of CKD in the United States is over 14% of the total population, with over 600,000 Americans suffering from the most severe form, end-stage renal disease (ESRD)2. The current treatment options available for those with ESRD include dialysis and kidney transplantation. Although approximately 25,000 patients undergo renal transplantation each year, a significant number of patients are added annually leading to a large disparity between those awaiting a life-saving organ and those receiving transplantation3. In addition to its serious negative effects on longevity and quality of life, dialysis is associated with an astonishing financial burden. In 2014, Medicare paid claims totaled over $30 billion for ESRD patients2. With a limited organ supply and no apparent downtrend in patients requiring dialysis, research efforts aimed at identifying alternative solutions to dialysis and transplantation are ever important. Even a relatively short delay in the need for dialysis increases a patient&#39;s number of quality-adjusted life years and productivity substantially while postponing dialysis-related costs4,5,6.
Solutions for functional tissue loss, like that in ESRD, are currently being studied in tissue engineering and regenerative medicine laboratories, with widely varied approaches ranging from scaffold-based organoid fabrication to whole organ engineering using decellularized organ structures for cellular implantation7,8,9,10,11. Recapitulating complex renal structures from marginal or discarded kidneys has only partially been investigated. In fact, nearly 20% of kidneys procured for transplantation are discarded for various reasons12,13. The functional renal tissue from these putative grafts could be utilized and incorporated into one or many tissue-engineered constructs. Prior studies have demonstrated the feasibility of working with these discarded organs, utilizing kidneys for the extra-cellular matrix for tissue engineering purposes14,15. However, few have used primary nephronal tissue from healthy kidneys for tissue-engineering purposes16,17,18.
One method previously described by Kim et al. involves isolation of renal &#34;segments&#34; from healthy rat kidneys, which were then seeded on polyglycolic acid (PGA) scaffolds for construct fabrication16. However, little information is given regarding exact dissection methodology, and segments were obtained from a combination of fine mincing and filtration. We describe a modification of this protocol, which similarly produces discrete renal segments with intact nephronal architecture, but instead relies on microdissection techniques. Nephrectomies are performed on living adult mice, after which the kidneys are transferred to the dissection microscope where the renal capsule is removed, and the tissue is further dissected. Small-bore 30&#189; G needles are used as cutting instruments and also as guides aiding in dissection, as the needle diameter is equal to the target diameter of the renal segments. The isolated, in this case murine, renal segments maintain viability in culture and incorporate with scaffold-free endothelial-fibroblast cellular constructs19. These constructs have previously been used to engineer other organs, including a bio-artificial pancreas20.

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			<td height="42" style="height:42px;width:173px;">Non-fenestrated Sterile Field</td>
			<td style="width:181px;">Busse Hospital Disposables</td>
			<td style="width:153px;">696</td>
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			<td height="42" style="height:42px;width:173px;">Fenestrated Sterile Field</td>
			<td style="width:181px;">Busse Hospital Disposables</td>
			<td style="width:153px;">697</td>
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			<td height="42" style="height:42px;width:173px;">Halsted Mosquito Forceps 5 Curved</td>
			<td style="width:181px;">Miltex</td>
			<td style="width:153px;">Mil-7-4</td>
			<td>&#34;Hemostat&#34; in manuscript</td>
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			<td height="63" style="height:63px;width:173px;">Extra Fine Graefe Forceps, Curved with teeth</td>
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			<td height="63" style="height:63px;width:173px;">Betadine Surgical Scrub with Pump, Povidone-iodine 7.5%</td>
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			<td style="width:153px;">67618-151-17</td>
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			<td height="42" style="height:42px;width:173px;">Sterile Cotton Gauze Pad (4&#34; x 4&#34;)</td>
			<td style="width:181px;">Fisher Healthcare</td>
			<td style="width:153px;">22-415-469</td>
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			<td height="42" style="height:42px;width:173px;">Penicillin/Streptomycin Solution, 100X</td>
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			<td style="width:153px;">30-002-Cl</td>
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			<td height="42" style="height:42px;width:173px;">Isoflurane, USP</td>
			<td style="width:181px;">Manufacturer: Piramal, Distributor: McKesson</td>
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			<td>Hair Removal Cream in text</td>
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			<td>Diluted to 70% Ethanol Solution</td>
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			<td style="width:153px;">130181</td>
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			<td style="width:181px;">Glad</td>
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			<td>Applied to Stereoscope</td>
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			<td height="21" style="height:21px;width:173px;">SZX16 Stereo Microscope</td>
			<td style="width:181px;">Olympus</td>
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			<td height="63" style="height:63px;width:173px;">Self-Supporting Dual-Light Pipe, 23&#34; L Gooseneck</td>
			<td style="width:181px;">Cole Parmer</td>
			<td style="width:153px;">EW-41720-60</td>
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			<td height="21" style="height:21px;width:173px;">Scalpel Handle #3</td>
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			<td style="width:153px;">Mil-4-7</td>
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			<td height="63" style="height:63px;width:173px;">Sterile Rib-Back Carbon Steel Blade, Blade Size 15</td>
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			<td style="width:153px;">371115</td>
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			<td height="21" style="height:21px;width:173px;">31 1/2 Gauge Needle</td>
			<td style="width:181px;">ThermoFisher Scientific</td>
			<td style="width:153px;">14-826F</td>
			<td style="width:199px;">Becton Dickinson 305106</td>
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			<td height="42" style="height:42px;width:173px;">Dulbecco&#39;s Modified Eagle&#39;s Medium</td>
			<td style="width:181px;">Corning</td>
			<td style="width:153px;">10-017-CV</td>
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			<td height="42" style="height:42px;width:173px;">Fetal Select 100% Bovine Serum</td>
			<td style="width:181px;">Atlas Biologicals</td>
			<td style="width:153px;">FS-0500-AD</td>
			<td></td>
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			<td height="42" style="height:42px;width:173px;">Normal Human Dermal Fibroblasts</td>
			<td style="width:181px;">Lonza</td>
			<td style="width:153px;">CC-2511</td>
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			<td height="63" style="height:63px;width:173px;">Human Adipose Microvascular Endothelial Cells</td>
			<td style="width:181px;">Sciencell Research Laboratories</td>
			<td style="width:153px;">7200</td>
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			<td height="21" style="height:21px;width:173px;">Surgical Loupes (2.5x)</td>
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			<td style="width:181px;">Lonza</td>
			<td style="width:153px;">CC-3131, CC-4126</td>
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			<td height="63" style="height:63px;width:173px;">EGM-2 (Endothelial Basal Medium with EGM-2 SingleQuots Added)</td>
			<td style="width:181px;">Lonza</td>
			<td style="width:153px;">CC-3156, CC-4176</td>
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			<td height="63" style="height:63px;width:173px;">Live/Dead Viability/Cytotoxicity Kit for Mammalian Cells</td>
			<td style="width:181px;">ThermoFisher Scientific</td>
			<td style="width:153px;">L3224</td>
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			<td height="42" style="height:42px;width:173px;">Anti-Cytokeratin-18 Antibody</td>
			<td style="width:181px;">Abcam</td>
			<td style="width:153px;">ab668</td>
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			<td height="42" style="height:42px;width:173px;">Goat anti-Mouse IgG, Alexa Fluor 633</td>
			<td style="width:181px;">ThermoFisher Scientific</td>
			<td style="width:153px;">A-21052</td>
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			<td height="42" style="height:42px;width:173px;">Goat anti-Rabbit IgG, Alexa Fluor 546</td>
			<td style="width:181px;">ThermoFisher Scientific</td>
			<td style="width:153px;">A-11010</td>
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			<td height="42" style="height:42px;width:173px;">Anti-Von Willebrand Factor Antibody</td>
			<td style="width:181px;">Abcam</td>
			<td style="width:153px;">ab6994</td>
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			<td height="63" style="height:63px;width:173px;">Albumin, Fluorescein isothiocyanate Conjugate</td>
			<td style="width:181px;">Sigma Aldrich</td>
			<td style="width:153px;">A9771-50MG</td>
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			<td height="21" style="height:21px;width:173px;">Hoescht 33342</td>
			<td style="width:181px;">BD Pharmingen</td>
			<td style="width:153px;">561908</td>
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			<td height="21" style="height:21px;width:173px;">Background Buster</td>
			<td style="width:181px;">Innovex Biosciences</td>
			<td style="width:153px;">NB306</td>
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microdissection of primary renal tissue segments and incorporation with novel scaffold-free construct technology

Kidney transplantation is now a mainstream therapy for end-stage renal disease. However, with approximately 96,000 people on the waiting list and only one-fourth of these patients achieving transplantation, there is a dire need for alternatives for those with failing organs. In order to decrease the harmful consequences of dialysis along with the overall healthcare costs it incurs, active investigation is ongoing in search of alternative solutions to organ transplantation. Implantable tissue-engineered renal cellular constructs are one such feasible approach to replacing lost renal functionality. Here, described for the first time, is the microdissection of murine kidneys for isolation of living corticomedullary renal segments. These segments are capable of rapid incorporation within scaffold-free endothelial-fibroblast constructs which may enable rapid connection with host vasculature once implanted. Adult mouse kidneys were procured from living donors, followed by stereoscope microdissection to obtain renal segments 200 - 300 &#181;m in diameter. Multiple renal constructs were fabricated using primary renal segments harvested from only one kidney. This method demonstrates a procedure which could salvage functional renal tissue from organs that would otherwise be discarded.

The protocol described produces approximately 50 renal segments per pyramidal 2 mm3 section of renal tissue. The renal segments that have been processed and imaged have tubular and glomerular components in differing proportions (see Figure 2). The intact segments were subjected to an assay in order to determine the viability of different segments once every 24 h for three days. Green-fluorescent calcein-AM is present with intracellular esterase act...

Watch this Scientific Journal Video about Microdissection of Primary Renal Tissue Segments and Incorporation with Novel Scaffold-free Construct Technology at JoVE.com

Microdissection of Primary Renal Tissue Segments and Incorporation with Novel Scaffold-free Construct Technology

Tissue-engineered renal constructs provide a solution for the organ shortage and deleterious effects of dialysis. Here, we describe a protocol to micro dissect murine kidneys for isolation of cortico-medullary segments. These segments are implanted into scaffold-free cellular constructs, forming renal organoids.

Kidney transplantation is now a mainstream therapy for end-stage renal disease. However, with approximately 96,000 people on the waiting list and only ...

The overall goal of this microscopic dissection procedure is to isolate discrete segments of living renal tissue with intact renal architecture for tissue engineering applications. This method can help answer key questions in the field of tissue engineering such as can whole segments of isolated primary organ tissue be harvested sterilely and be kept alive in culture? The main advantage of this technique is the segments contain intact renal architecture as opposed to using cell lines to recreate a complex organ with over 26 different cell types.The implications of this technique extend towards therapy of end-stage renal disease because these constructs will improve filtration and may help patients stay off dialysis. During the surgery, wear proper surgical gear including a mask and a cap to minimize the risk of contamination. Likewise, make every effort to maintain sterility throughout.Start preparations by draping the operating table. Next, open the pack of autoclaved instruments onto the sterile drapes. They must include three small hemostats, fine forceps with teeth, fine forceps without teeth, and straight iris scissors.Cover the center of the operating table with a second non-fenestrated surgical drape. Prior to setting up the operating room, prepare 50 milliliters of antibiotic supplemented DBPS and aliquot five milliliters into a 15 milliliter tube. Now anesthetize an eight to 12-week-old C57 black six mouse and periodically monitor the level of anesthesia by assessing its pedal reflex with a firm toe pinch.Next, use a hair removal cream to remove all of the hair from the ventral torso area and rinse off the cream and hair with distilled water. Then transfer the mouse to the operating table and place it supine under the non-fenestrated drape. Now cut out a two centimeter square fenestration in the drape over the mouse's abdomen.Then scrub the exposed skin with povidone-iodine followed by 70%ethanol three times to sterilize the skin and complete the preparations for the surgery. Begin the surgery by using fine forceps with teeth and iris scissors. Make a three to four centimeter skin incision parallel to the midline one-half centimeter to the left of the midline.Next, grasp the peritoneum using fine forceps without teeth and incise with iris scissors to enter the abdominal cavity. Then apply hemostats to the superior and inferior lateral edges of skin and peritoneum to place tension laterally and enhance the exposure. Now delicately shift the intestinal contents to the right of the abdomen to expose the left kidney.Then gently place traction on the kidney to elevate it out of the abdomen. Now place a hemostat across the hilum of the kidney and use iris scissors to transect the ureter and renal vessels. Then transfer the kidney to the tube of 1%pen-strep DBPS on ice.Take this tube to a sterile culture hood for processing. There transfer the kidney to a 60 millimeter Petri dish and rinse it twice with fresh five milliliters of DPBS containing calcium and magnesium. After the second wash, suspend the kidney in fresh five milliliters of DBPS in a new 60 millimeter dish.Then prepare an additional Petri dish containing only five milliliters of DBPS for later use. Continue using sterile technique including sterile gloves, surgical mask, and bouffant to minimize contamination risks. Then drape the stage area and area surrounding the stereo microscope.Next, place plastic adhesive sheets on the microscope focus knobs and spray them with 70%ethanol. Then turn on the dual gooseneck illuminator to light the stage. Now onto the sterile drapes, open a package of sterilized instruments containing fine forceps without teeth, a scalpel handle, a number 15 scalpel blade, two straight hemostats, and two 30.5 gauge hollow-bore needles.Place the number 15 blade onto the scalpel handle and attach one hemostat to each needle adapter hub to create needle dissection instruments. Now transfer the two dishes, one with the kidney in DPBS and the other only DPBS, to the microscope area. Remove the lid on the kidney dish and focus the microscope on the anterior or posterior surface of the kidney at 3.2 to 4X magnification.Next, with the non-dominant hand, use fine forceps without teeth to pierce and pin the kidney against the dish at the inferior and superior poles of the kidney. Then with the dominant hand, use the number 15 blade to remove the translucent fibrous capsular layer from the exposed surface. Shave the most superficial 0.5 millimeters from the exposed surface of the kidney surface to remove the remainder of the capsule.Continue by using the number 15 blade to dissect an inverted pyramid of tissue from the de-capsulated area that is approximately two square millimeters. Then transfer the tissue into the clean dish of DBPS and discard the remainder of the kidney. Now focus on the dissected tissue and decrease the magnification to 1.5 to 2.0X.Using the two hemostat needle instruments as cutting tools, slice the tissue fragment into progressively smaller pieces until the tissue segments are the size of the needle tips or smaller. About 50 segments should be produced. This is a critical portion of the procedure.Each segment needs to closely approximate the diameter of the 30-1/2 gauge needle tip to avoid large segments which could hinder diffusion. Return the tissue to the tissue culture hood and remove the DPBS using a P1000 micropipette. Then add back five millimeters of DMEM supplemented with 10%fetal bovine serum and 1%pen-strep.Then culture the tissue or implant it within cellular constructs immediately. The viability of the intact renal segments produced by the described procedure was examined over three days in culture using a viability assay. Green fluorescent calcium AM is present with intracellular esterase activity indicative of living cells.Red fluorescent ethidium homodimer-1 is seen with loss of integrity of the plasma membrane. When the renal segments were embedded in scaffold-free endothelial fibroblast constructs, by day three they were incorporated with the cellular constructs to form intact structures. The constructs maintained their pre-vascular endothelial network shown by labeling with von Willebrand factor.Renal epithelial cells can be seen in green labeled by cytokertain-18. To test in-vitro renal functionality, the constructs were incubated with FITC-labeled albumin. While there was residual albumin found away from the segments of embedded renal tissue, there were also hotspots in the renal tubular epithelial cells.These hotspots are albumin that traverses intraluminally which is thought to represent albumin reuptake in the renal segment cellular construct. After watching this video, you should have a good understanding of how to isolate renal segments from murine kidneys for tissue engineering applications. Once mastered, this procedure can be done in one to 1-1/2 hours.Following this procedure, other methods including seeding cellularized constructs can be performed in order to answer other questions regarding renal construct fabrication and characterization. Don't forget that working with surgical instruments and pressurized oxygen cylinders can be extremely hazardous. Be careful when working with sharp objects and remember to anchor oxygen tanks to a lab bench.

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Research

JoVE Journal

Bioengineering

Magnetic Resonance Elastography Methodology for the Evaluation of Tissue Engineered Construct Growth

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use of destructive assessment is not acceptable. A proposed alternative is the use of an imaging process called magnetic resonance elastography. Elastography is a nondestructive method for determining the engineered outcome by measuring local mechanical property values (i.e., complex shear modulus), which are essential markers for identifying the structure and functionality of a tissue. As a noninvasive means for evaluation, the monitoring of engineered constructs with imaging modalities such as magnetic resonance imaging (MRI) has seen increasing interest in the past decade1. For example, the magnetic resonance (MR) techniques of diffusion and relaxometry have been able to characterize the changes in chemical and physical properties during engineered tissue development2. The method proposed in the following protocol uses microscopic magnetic resonance elastography (&mu;MRE) as a noninvasive MR based technique for measuring the mechanical properties of small soft tissues3. MRE is achieved by coupling a sonic mechanical actuator with the tissue of interest and recording the shear wave propagation with an MR scanner4. Recently, &mu;MRE has been applied in tissue engineering to acquire essential growth information that is traditionally measured using destructive mechanical macroscopic techniques5. In the following procedure, elastography is achieved through the imaging of engineered constructs with a modified Hahn spin-echo sequence coupled with a mechanical actuator. As shown in Figure 1, the modified sequence synchronizes image acquisition with the transmission of external shear waves; subsequently, the motion is sensitized through the use of oscillating bipolar pairs. Following collection of images with positive and negative motion sensitization, complex division of the data produce a shear wave image. Then, the image is assessed using an inversion algorithm to generate a shear stiffness map6. The resulting measurements at each voxel have been shown to strongly correlate (R2&gt;0.9914) with data collected using dynamic mechanical analysis7. In this study, elastography is integrated into the tissue development process for monitoring human mesenchymal stem cell (hMSC) differentiation into adipogenic and osteogenic constructs as shown in Figure 2.

The procedure demonstrates the methodology of magnetic resonance elastography for monitoring the engineered outcome of adipose and osteogenic tissue engineered constructs through noninvasive local assessment of the mechanical properties using microscopic magnetic resonance elastography (&mu;MRE).

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use ...

Non-contact, Label-free Monitoring of Cells and Extracellular Matrix using Raman Spectroscopy

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, currently available routine methods require processing steps and alter sample integrity. Raman spectroscopy is a fast method that enables the measurement of biological samples without the need for further processing steps. This laser-based technology detects the inelastic scattering of monochromatic light.6 As every chemical vibration is assigned to a specific Raman band (wavenumber in cm-1), each biological sample features a typical spectral pattern due to their inherent biochemical composition.7-9 Within Raman spectra, the peak intensities correlate with the amount of the present molecular bonds.1 Similarities and differences of the spectral data sets can be detected by employing a multivariate analysis (e.g. principal component analysis (PCA)).10
Here, we perform Raman spectroscopy of living cells and native tissues. Cells are either seeded on glass bottom dishes or kept in suspension under normal cell culture conditions (37 &deg;C, 5% CO2) before measurement. Native tissues are dissected and stored in phosphate buffered saline (PBS) at 4 &deg;C prior measurements. Depending on our experimental set up, we then either focused on the cell nucleus or extracellular matrix (ECM) proteins such as elastin and collagen. For all studies, a minimum of 30 cells or 30 random points of interest within the ECM are measured. Data processing steps included background subtraction and normalization.

Raman spectroscopy is a suitable technique for the non-contact, label-free analysis of living cells, tissue-engineered constructs and native tissues. Source-specific spectral fingerprints can be generated and analyzed using multivariate analysis.

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, ...

Human Cartilage Tissue Fabrication Using Three-dimensional Inkjet Printing Technology

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and regenerative medicine. With digital control&#160;cells, scaffolds, and growth factors can be precisely deposited to the desired two-dimensional (2D) and three-dimensional (3D) locations rapidly. Therefore, this technology is an ideal approach to fabricate tissues mimicking their native anatomic structures. In order to engineer cartilage with native zonal organization, extracellular matrix composition (ECM), and mechanical properties, we developed a bioprinting platform using a commercial inkjet printer with simultaneous photopolymerization capable for 3D cartilage tissue engineering. Human chondrocytes suspended in poly(ethylene glycol) diacrylate (PEGDA) were printed for 3D neocartilage construction via layer-by-layer assembly. The printed cells were fixed at their original deposited positions, supported by the surrounding scaffold in simultaneous photopolymerization. The mechanical properties of the printed tissue were similar to the native cartilage. Compared to conventional tissue fabrication, which requires longer UV exposure, the viability of the printed cells with simultaneous photopolymerization was significantly higher. Printed neocartilage demonstrated excellent glycosaminoglycan (GAG) and collagen type II production, which was consistent with gene expression. Therefore, this platform is ideal for accurate cell distribution and arrangement for anatomic tissue engineering.

The methods described in this paper show how to convert a commercial inkjet printer into a bioprinter with simultaneous UV polymerization. The printer is capable of constructing 3D tissue structure with cells and biomaterials. The study demonstrated here constructed a 3D neocartilage.

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and ...

A Novel Stretching Platform for Applications in Cell and Tissue Mechanobiology

Tools that allow the application of mechanical forces to cells and tissues or that can quantify the mechanical properties of biological tissues have contributed dramatically to the understanding of basic mechanobiology. These techniques have been extensively used to demonstrate how the onset and progression of various diseases are heavily influenced by mechanical cues. This article presents a multi-functional biaxial stretching (BAXS) platform that can either mechanically stimulate single cells or quantify the mechanical stiffness of tissues. The BAXS platform consists of four voice coil motors that can be controlled independently. Single cells can be cultured on a flexible substrate that can be attached to the motors allowing one to expose the cells to complex, dynamic, and spatially varying strain fields. Conversely, by incorporating a force load cell, one can also quantify the mechanical properties of primary tissues as they are exposed to deformation cycles. In both cases, a proper set of clamps must be designed and mounted to the BAXS platform motors in order to firmly hold the flexible substrate or the tissue of interest. The BAXS platform can be mounted on an inverted microscope to perform simultaneous transmitted light and/or fluorescence imaging to examine the structural or biochemical response of the sample during stretching experiments. This article provides experimental details of the design and usage of the BAXS platform and presents results for single cell and whole tissue studies. The BAXS platform was used to measure the deformation of nuclei in single mouse myoblast cells in response to substrate strain and to measure the stiffness of isolated mouse aortas. The BAXS platform is a versatile tool that can be combined with various optical microscopies in order to provide novel mechanobiological insights at the sub-cellular, cellular and whole tissue levels.

We present in this article a novel stretching platform that can be used to investigate single cell responses to complex anisotropic biaxial mechanical deformation and quantify the mechanical properties of biological tissues.

Tools that allow the application of mechanical forces to cells and tissues or that can quantify the mechanical properties of biological tissues have ...

Epithelial Cell Repopulation and Preparation of Rodent Extracellular Matrix Scaffolds for Renal Tissue Development

This protocol details the generation of acellular, yet biofunctional, renal extracellular matrix (ECM) scaffolds that are useful as small-scale model substrates for organ-scale tissue development. Sprague Dawley rat kidneys are cannulated by inserting a catheter into the renal artery and perfused with a series of low-concentration detergents (Triton X-100 and sodium dodecyl sulfate (SDS)) over 26 hr to derive intact, whole-kidney scaffolds with intact perfusable vasculature, glomeruli, and renal tubules. Following decellularization, the renal scaffold is placed inside a custom-designed perfusion bioreactor vessel, and the catheterized renal artery is connected to a perfusion circuit consisting of: a peristaltic pump; tubing; and optional probes for pH, dissolved oxygen, and pressure. After sterilizing the scaffold with peracetic acid and ethanol, and balancing the pH (7.4), the kidney scaffold is prepared for seeding via perfusion of culture medium within a large-capacity incubator maintained at 37 &#176;C and 5% CO2. Forty million renal cortical tubular epithelial (RCTE) cells are injected through the renal artery, and rapidly perfused through the scaffold under high flow (25 ml/min) and pressure (~230 mmHg) for 15 min before reducing the flow to a physiological rate (4 ml/min). RCTE cells primarily populate the tubular ECM niche within the renal cortex, proliferate, and form tubular epithelial structures over seven days of perfusion culture. A 44 &#181;M resazurin solution in culture medium is perfused through the kidney for 1 hr during medium exchanges to provide a fluorometric, redox-based metabolic assessment of cell viability and proliferation during tubulogenesis. The kidney perfusion bioreactor permits non-invasive sampling of medium for biochemical assessment, and multiple inlet ports allow alternative retrograde seeding through the renal vein or ureter. These protocols can be used to recellularize kidney scaffolds with a variety of cell types, including vascular endothelial, tubular epithelial, and stromal fibroblasts, for rapid evaluation within this system.

This protocol describes decellularization of Sprague Dawley rat kidneys by antegrade perfusion of detergents through the vasculature, producing acellular renal extracellular matrices that serve as templates for repopulation with human renal epithelial cells. Recellularization and use of the resazurin perfusion assay to monitor growth is performed within specially-designed perfusion bioreactors.

This protocol details the generation of acellular, yet biofunctional, renal extracellular matrix (ECM) scaffolds that are useful as small-scale model ...

Three-dimensional Biomimetic Technology: Novel Biorubber Creates Defined Micro- and Macro-scale Architectures in Collagen Hydrogels

Tissue scaffolds play a crucial role in the tissue regeneration process. The ideal scaffold must fulfill several requirements such as having proper composition, targeted modulus, and well-defined architectural features. Biomaterials that recapitulate the intrinsic architecture of in vivo tissue are vital for studying diseases as well as to facilitate the regeneration of lost and malformed soft tissue. A novel biofabrication technique was developed which combines state of the art imaging, three-dimensional (3D) printing, and selective enzymatic activity to create a new generation of biomaterials for research and clinical application. The developed material, Bovine Serum Albumin rubber, is reaction injected into a mold that upholds specific geometrical features. This sacrificial material allows the adequate transfer of architectural features to a natural scaffold material. The prototype consists of a 3D collagen scaffold with 4 and 3 mm channels that represent a branched architecture. This paper emphasizes the use of this biofabrication technique for the generation of natural constructs. This protocol utilizes a computer-aided software (CAD) to manufacture a solid mold which will be reaction injected with BSA rubber followed by the enzymatic digestion of the rubber, leaving its architectural features within the scaffold material.

An innovative biofabrication technique was developed to engineer three-dimensional constructs that resemble the architectural features, components, and mechanical properties of in vivo tissue. This technique features a newly developed sacrificial material, BSA rubber, which transfers detailed spatial features, reproducing the in vivo architectures of a wide variety of tissues.

Tissue scaffolds play a crucial role in the tissue regeneration process. The ideal scaffold must fulfill several requirements such as having proper ...

Melt Electrospinning Writing of Three-dimensional Poly(&#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology with great potential for biomedical applications. The technique facilitates the direct deposition of biocompatible polymer fibers to fabricate well-ordered scaffolds in the sub-micron to micro scale range. The establishment of a stable, viscoelastic, polymer jet between a spinneret and a collector is achieved using an applied voltage and can be direct-written. A significant benefit of a typical porous scaffold is a high surface-to-volume ratio which provides increased effective adhesion sites for cell attachment and growth. Controlling the printing process by fine-tuning the system parameters enables high reproducibility in the quality of the printed scaffolds. It also provides a flexible manufacturing platform for users to tailor the morphological structures of the scaffolds to their specific requirements. For this purpose, we present a protocol to obtain different fiber diameters using melt electrospinning writing (MEW) with a guided amendment of the parameters, including flow rate, voltage and collection speed. Furthermore, we demonstrate how to optimize the jet, discuss often experienced technical challenges, explain troubleshooting techniques and showcase a wide range of printable scaffold architectures.

Melt Electrospinning Writing of Three-dimensional Poly(&amp;#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This protocol serves as a comprehensive guideline to fabricate scaffolds via electrospinning with polymer melts in a direct writing mode. We systematically outline the process and define the appropriate parameter settings for achieving targeted scaffold architectures.

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology ...

Bioprinting of Cartilage and Skin Tissue Analogs Utilizing a Novel Passive Mixing Unit Technique for Bioink Precellularization

Bioprinting is a powerful technique for the rapid and reproducible fabrication of constructs for tissue engineering applications. In this study, both cartilage and skin analogs were fabricated after bioink pre-cellularization utilizing a novel passive mixing unit technique. This technique was developed with the aim to simplify the steps involved in the mixing of a cell suspension into a highly viscous bioink. The resolution of filaments deposited through bioprinting necessitates the assurance of uniformity in cell distribution prior to printing to avoid the deposition of regions without cells or retention of large cell clumps that can clog the needle. We demonstrate the ability to rapidly blend a cell suspension with a bioink prior to bioprinting of both cartilage and skin analogs. Both tissue analogs could be cultured for up to 4 weeks. Histological analysis demonstrated both cell viability and deposition of tissue specific extracellular matrix (ECM) markers such as glycosaminoglycans (GAGs) and collagen I respectively.

Cartilage and skin analogs were bioprinted using a nanocellulose-alginate based bioink. The bioinks were cellularized prior to printing via a single step passive mixing unit. The constructs were demonstrated to be uniformly cellularized, have high viability, and exhibit favorable markers of differentiation.

Bioprinting is a powerful technique for the rapid and reproducible fabrication of constructs for tissue engineering applications. In this study, both ...

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids

Nature has a variety of possibilities to create new protein functions by modifying the sequence of the individual amino acid building blocks. However, all variations are based on the 20 canonical amino acids (cAAs). As a way to introduce additional physicochemical properties into polypeptides, the incorporation of non-canonical amino acids (ncAAs) is increasingly used in protein engineering. Due to their relatively short length, the modification of ribosomally synthesized and post-translationally modified peptides by ncAAs is particularly attractive. New functionalities and chemical handles can be generated by specific modifications of individual residues. The selective pressure incorporation (SPI) method utilizes auxotrophic host strains that are deprived of an essential amino acid in chemically defined growth media. Several structurally and chemically similar amino acid analogs can then be activated by the corresponding aminoacyl-tRNA synthetase and provide residue-specific cAA(s) &#8594; ncAA(s) substitutions in the target peptide or protein sequence. Although, in the context of the SPI method, ncAAs are also incorporated into the host proteome during the phase of recombinant gene expression, the majority of the cell&#39;s resources are assigned to the expression of the target gene. This enables efficient residue-specific incorporation of ncAAs often accompanied with high amounts of modified target. The presented work describes the in vivo incorporation of six proline analogs into the antimicrobial peptide nisin, a lantibiotic naturally produced by Lactococcus lactis. Antimicrobial properties of nisin can be changed and further expanded during its fermentation and expression in auxotrophic Escherichia coli strains in defined growth media. Thereby, the effects of residue-specific replacement of cAAs with ncAAs can deliver changes in antimicrobial activity and specificity. Antimicrobial activity assays and fluorescence microscopy are used to test the new nisin variants for growth inhibition of a Gram-positive Lactococcus lactis indicator strain. Mass spectroscopy is used to confirm ncAA incorporation in bioactive nisin variants.

The protocol presents the Escherichia coli-based selective pressure incorporation of non-canonical amino acids (ncAAs) into the lactococcal antimicrobial peptide nisin. Its properties can be changed during recombinant expression via substitution with desired ncAAs in defined growth media. Resulting changes in bioactivity are mapped by growth inhibition assays and fluorescence microscopy.

Nature has a variety of possibilities to create new protein functions by modifying the sequence of the individual amino acid building blocks. However, all ...

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.