The authors would like to acknowledge the start-up fund and department of surgery research grant from Southern Illinois University, School of Medicine; and the Memorial Medical Foundation grant.

1. Surgical Retrieval
Note: An IRB approval was obtained to collect the ACL stump during ACL reconstruction surgery. IRB exemption was given as the ACL stump used were generally discarded as surgical waste. 20 patients were used to collect the ACL stump.
<ol>
	<li>Administer general anesthesia and pre-operative antibiotics as per institution's protocol to the patient.</li>
	<li>Apply tourniquet and inflate 100 mg above systolic blood pressure.</li>
	<li>Situate the patient in the supine position. Make a horizontal anterolateral incision with knee in 30-45&#176; flexion for a 5 mm portal and insert the arthroscopic trocar and camera into the suprapatellar pouch at 30&#176;.</li>
	<li>Perform a routine diagnostic arthroscopy.</li>
	<li>Enter a notch and debride the membranous synovium over the torn ACL.</li>
	<li>Use a 4.5 mm shaver and ablator to identify the ACL stump.</li>
	<li>Use a duckbill straight bitter to collect multiple specimens from the remaining ACL stump.</li>
	<li>Maintain the sample in normal saline in a sterile container.</li>
	<li>Send the samples to pathology for decoding and final delivery to the laboratory facility.</li>
	<li>Recover patient and perform post-operative care as per institution's protocol.</li>
</ol>
2. Tissue Digestion and hACL Isolation
<ol>
	<li>Transfer the human ACL tissue received from pathology to a Petri dish with sterile saline/PBS (Phosphate buffered saline).</li>
	<li>Mince the tissue using sterile scissors into 1-2 mm3 pieces and wash the minced tissue with saline at least 3 times.</li>
	<li>Digest the minced tissue with 0.4% Collagenase in DMEM/F-12 (50/50, 1x) medium supplemented with 10% fetal bovine serum (FBS) and 1% Penicillin/Streptomycin for 4-6 hr at 37 &#176;C.</li>
	<li>Centrifuge the cells at 1,000 x g for 5 min and then resuspend the cells in the medium.</li>
	<li>Wash the cells with the medium for 2-3 times and then seed/culture in T-25 flasks for 2-3 days.</li>
</ol>
3. Cellular Expansion, Freezing and Thawing
<ol>
	<li>Use a light microscope to visualize the cells cultured for 2-3 days in a T-25 flask.</li>
	<li>Maintain the cells at 37 &#176;C in the DMEM/F-12 (50/50, 1x) medium supplemented with 10% fetal bovine serum (FBS) and 1% Penicillin/Streptomycin (P/S). 
	Note: Change the media when cells show adherence and standard morphology. Use a light microscope to observe the cells.</li>
	<li>Wash the confluent cells with PBS at day 7 (~1.3 X 106 cells/flask). Add Trypsin (0.5 g/L) and incubate the cells at 37 &#176;C for 5 min. Add media to suspended cells to neutralize trypsin. Divide the media-cell mixture between three T-25 flasks.</li>
	<li>Wash the confluent cells with PBS, add trypsin (0.5 g/L), and resuspend them in freezing medium containing DMSO, FBS and the complete medium (DMEM/F-12 Medium + 10% FBS + 1% P/S) in the ratio 1:2:7.</li>
	<li>Store the cryogenic vials at -80 &#176;C if the cells will be used within a month, and in liquid nitrogen if the cells will be stored for longer durations.</li>
	<li>Thaw the vials in a 37 &#176;C water bath for reuse. 
	Note: Typically 90-95% cells survive.</li>
</ol>
4. Fabrication of Tissue Engineered 2-D Poly Lactic-co-glycolic Acid (PLAGA) Scaffold
<ol>
	<li>Dissolve 1 g of PLAGA in 12 ml dichloromethane in a 20 ml scintillation vial and vortex the solution for 8 hr at a constant speed (800 rpm). 
	Note: Detailed description in Gupta et al.15</li>
	<li>Transfer the dissolved solution to a glass Petri dish lined with Fluorinated protection paper.</li>
	<li>Place the Petri dish under a vacuum hood for 30 min. Leave the Petri dish at -20 &#176;C overnight and then at room temperature. Place the Petri dishes in lyophilizer to ensure complete evaporation of the solvent to obtain thin films of the polymer.</li>
	<li>Place the polymer films in a desiccator for 24 hr.</li>
	<li>Cut the polymer films into 12 mm diameter circular disks and store them in a desiccator until needed.</li>
</ol>
5. Scanning Electron Microscopy (SEM)
<ol>
	<li>Wash the cells (50,000 cells/disk) seeded on the control TCPS and the PLAGA scaffold with PBS 7 days subsequent to seeding.</li>
	<li>Use 1.5% Glutaraldehyde in 0.1 M Cacodylate buffer to fix the cells and 2.5% OsO4 in 0.1 M Cacodylate buffer for post-fixation.</li>
	<li>Wash the fixed cells with 0.1 M Cacodylate buffer. Dry the fixed cells using serial ethanol dehydration (50%, 70%, 80%, 90% and 100%) for 15 min each, and further dry in Hexamethyldisilazane (HMDS) overnight.</li>
	<li>Vent the chamber of SEM sputter coating system with button valve and raise the top plate.</li>
	<li>Place the dried samples in chamber. Lower the top plate.</li>
	<li>Switch the control knob to pump to start evacuating the chamber.</li>
	<li>Open argon leak valve. Wait for the vacuum to drop to 0.05 mbar.</li>
	<li>Coat the dried samples with a thin layer (0.13 nm) of Gold/Palladium.</li>
	<li>Return the argon leak valve to its closed position.</li>
	<li>Switch the control knob to off.</li>
	<li>Vent the chamber with button valve and raise the top plate.</li>
	<li>Remove the samples and store them in a desiccator for 24 hr.</li>
	<li>Observe the samples under an scanning electron microscope.</li>
</ol>
6. Immunofluorescence Staining
<ol>
	<li>Wash the cells (50,000 cells/disk) seeded on the control TCPS and the PLAGA scaffold with PBS 7 days subsequent to seeding.</li>
	<li>Fix the cells using 70% ethanol (cold) for 10 min.</li>
	<li>Incubate the fixed cells at room temperature with 1% Bovine Serum Albumin (BSA) in PBS having 0.05% Triton X-100 for 20 min.</li>
	<li>Immerse the samples in 1% Tween at room temperature for 20 min.</li>
	<li>Add monoclonal mouse Anti-&#946;-actin antibody (1:400) and incubate the cells overnight at 4 &#176;C.</li>
	<li>Wash the cells with 0.05% Tween. Add secondary antibody (goat anti-mouse F (ab') 2 fragment of IgG conjugated with a fluorescence probe, 1:400) to the cells and incubate for 1 hr at room temperature.</li>
	<li>Wash the cells with the PBS. Stain the cells with nuclear stain and mount using 80% Glycerol.</li>
	<li>Observe the cells under a confocal microscope.</li>
</ol>

<ol>
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The authors declare that they have no competing financial interests.

The primary objective of this hACL/2D scaffold study was to use the obtained cells in a patch to augment primary repair of partial ACL tears. Nonoperative management of partial ACL tears may include a short period of immobilization, bracing, a progressive rehabilitation program, and regular follow-up evaluations 13,16,17. However, many studies show that conservative treatment in athletes has been associated with poor results and failure. Buckley et al. evaluated 25 patients with partial ACL tears at i...

The anterior cruciate ligament (ACL) is a commonly injured intra-articular ligament of the knee. Approximately 200,000 (ACL) injuries are reported annually in the United States. Over 75% of patients experiencing ACL injury opt for orthopedic reconstructive surgery 1,2,3,4. Surgical intervention is often indicated due to an inherently poor healing potential3. ACL reconstruction is typically accomplished by means of an autograft or allograft tendon. Autograft and allograft represent the gold standard for reconstruction as they boast high success rates, and primary suture repair, the other treatment option, has shown failure rates of up to 94% 5,6,7.
Partial tears of the ACL represent 10% to 28% of all ACL tears8. In a prospective study, Noyes et al. estimated that 50% of patients with partial tears affecting more than half of the ACL progressed to complete ACL insufficiency after non-operative treatment9. Other studies report persistent instability and decreased function with fewer than 30% of patients able to return to their pre-injury activity level 9,10,11,12,13. Treatment options are limited and include conservative modalities, thermal shrinkage of remaining ACL, or ACL reconstruction. Recently, there has been increased interest in augmented primary repair. These techniques use biologics to enhance primary suture repairs14. Recent research has attempted to harvest mesenchymal-like hACL derived stem cells to circumvent graft limitations,31,32 but the validity and efficacy of these cells is still unknown. The ideal cell source for tissue engineering applications seems to be non-mesechymal hACL derived fibroblast cells.
Current research is focused on identifying a suitable matrix material and cell source for the engineered scaffold. It is standard procedure for a torn ACL to be discarded as surgical waste during reconstruction surgery, however, this damaged ligament may be a quality source for the acquisition of cells needed to develop and enhance an ideal tissue engineered ACL replacement. Our lab has developed a protocol for the in vitro expansion of these harvested hACL derived cells. Using an engineered 2D matrix infused with hACL derived cells, we have designed a patch that could potentially augment partial ACL repair and strengthen torn ligaments.

<table border="0" cellpadding="0" cellspacing="0" style="width:1004px;" width="1003">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Name of Material/ Equipment</td>
			<td style="width:139px;">Company</td>
			<td style="width:143px;">Catalog Number</td>
			<td style="width:507px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Petri-dish</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">08-757-103C</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:216px;">Phosphate Buffered Saline (PBS)</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">BP3994</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Collagenase</td>
			<td style="width:139px;">Gibco</td>
			<td style="width:143px;">17018-029</td>
			<td>Store at 40C</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">DMEM/F-12</td>
			<td style="width:139px;">Cellgro</td>
			<td style="width:143px;">10-092-CV</td>
			<td>Store at 40C. Warm in 370C water bath before use.</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:139px;">Gibco</td>
			<td style="width:143px;">10082</td>
			<td>Store at -800C</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Penicillin/Streptomycin</td>
			<td style="width:139px;">Lonza</td>
			<td style="width:143px;">17-602E</td>
			<td>Store at 40C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Centrifuge Tubes- 15 ml</td>
			<td style="width:139px;">Corning</td>
			<td style="width:143px;">430790</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">T-25 flasks</td>
			<td style="width:139px;">BD Falcon</td>
			<td style="width:143px;">3013</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Trypsin-Versene mixture</td>
			<td style="width:139px;">Lonza</td>
			<td style="width:143px;">17-161E</td>
			<td>Store at 40C. Warm in 370C water bath before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DMSO</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">BP231-100</td>
			<td>Combustible liquid. Can cause skin, eye and respiratory tract irritation.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cryogenic vials</td>
			<td style="width:139px;">Corning</td>
			<td style="width:143px;">430489</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">PLAGA</td>
			<td style="width:139px;">Purac Biomaterials</td>
			<td style="width:143px;">Purasorb PLG8523</td>
			<td>Store at -800C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">TCPS disks</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">12-545-82</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:216px;">Dichloromethane</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">AC36423-0010</td>
			<td>Possible cancer hazard. Store in a dry, cool place.</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Bytac paper</td>
			<td style="width:139px;">Saint gobin performance plastics</td>
			<td style="width:143px;">1420652</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scintillation vial</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td>03-339-21G</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Bovine Serum Albumin (BSA)</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td style="width:143px;">A7906</td>
			<td>Store at 40C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tween</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">BP337-500</td>
			<td></td>
		</tr>
		<tr height="46">
			<td height="46" style="height:46px;width:216px;">mouse Anti-&#946;-actin antibody (10 Ab)</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td style="width:143px;">A5441</td>
			<td>Store at -200C</td>
		</tr>
		<tr height="46">
			<td height="46" style="height:46px;width:216px;">goat-anti-mouse antibody (20 Ab)</td>
			<td style="width:139px;">Cell Signaling</td>
			<td style="width:143px;">4408</td>
			<td>Store at -200C</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Hoechst dye</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td style="width:143px;">14530</td>
			<td>Store at -200C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glycerol</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">BP229-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glutaraldehyde</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">BP2547-1</td>
			<td>Toxic by inhalation and if swallowed. Causes burns by all exposure routes.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hexamethyldisilazane</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:143px;">AC43085-1000</td>
			<td>Flammable liquid and vapor. Causes burns by all exposure routes.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sterile Scissors</td>
			<td style="width:139px;">McKesson</td>
			<td style="width:143px;">25-716</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Centrifuge</td>
			<td style="width:139px;">Eppendorf</td>
			<td style="width:143px;">5804R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Light Microscope</td>
			<td style="width:139px;">Olympus</td>
			<td style="width:143px;">CK40</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Water Bath</td>
			<td style="width:139px;">Thermo scientific</td>
			<td style="width:143px;">2845</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Vortex</td>
			<td style="width:139px;">Labnet&#160;</td>
			<td style="width:143px;">VX-200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glass Petri plates</td>
			<td style="width:139px;">fisher Scientific</td>
			<td style="width:143px;">S31473</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Acu-Punch</td>
			<td style="width:139px;">Acuderm Inc.</td>
			<td style="width:143px;">P1225</td>
			<td>Acu-Punch was used to cut 12mm disks</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cacodylate buffer</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td style="width:143px;">97068</td>
			<td>Flammable liquid, carcinogen and irritant.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Osmium tetraoxide</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td style="width:143px;">201030</td>
			<td>Highly toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Triton X-100</td>
			<td style="width:139px;">Sigma Aldrich</td>
			<td style="width:143px;">T8787</td>
			<td>Harmful if swallowed</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ethanol</td>
			<td style="width:139px;">Decon Labs</td>
			<td style="width:143px;">2705</td>
			<td>Keep away from heat, sparks, flame and other form of ignition.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">General/regional Anesthesia</td>
			<td style="width:139px;">Amphastar pharmaceuticals</td>
			<td style="width:143px;"></td>
			<td>1% Lidocaine, 0.25% Bupivacaine,Anesthetic agents for induction and maintenance</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Antibiotics</td>
			<td style="width:139px;">Hospira</td>
			<td>0409-0805-01</td>
			<td>Ancef 1g i.v.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Arthroscopy trocar</td>
			<td style="width:139px;">Smith and Nephew</td>
			<td style="width:143px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Arthroscopy Camera</td>
			<td style="width:139px;">Smith and Nephew</td>
			<td style="width:143px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Arthroscopic grasper and bitter</td>
			<td style="width:139px;">Arthrex&#160;</td>
			<td style="width:143px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">4.5mm shaver</td>
			<td style="width:139px;">Arthrex&#160;</td>
			<td style="width:143px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Interference Screws</td>
			<td style="width:139px;">Arthrex&#160;</td>
			<td style="width:143px;"></td>
			<td>stainless steel screws</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sputter Coater</td>
			<td style="width:139px;">Polaron</td>
			<td style="width:143px;">E5400</td>
			<td></td>
		</tr>
	</tbody>
</table>

surgical retrieval, isolation and in vitro expansion of human anterior cruciate ligament-derived cells for tissue engineering applications

Injury to the ACL is a commonly encountered problem in active individuals. Even partial tears of this intra-articular knee ligament lead to biomechanical deficiencies that impair function and stability. Current options for the treatment of partial ACL tears range from nonoperative, conservative management to multiple surgical options, such as: thermal modification, single-bundle repair, complete reconstruction, and reconstruction of the damaged portion of the native ligament. Few studies, if any, have demonstrated any single method for management to be consistently superior, and in many cases patients continue to demonstrate persistent instability and other comorbidities.
The goal of this study is to identify a potential cell source for utilization in the development of a tissue engineered patch that could be implemented in the repair of a partially torn ACL. A novel protocol was developed for the expansion of cells derived from patients undergoing ACL reconstruction. To isolate the cells, minced hACL tissue obtained during ACL reconstruction was digested in a Collagenase solution. Expansion was performed using DMEM/F12 medium supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin (P/S). The cells were then stored at -80 &#186;C or in liquid nitrogen in a freezing medium consisting of DMSO, FBS and the expansion medium. After thawing, the hACL derived cells were then seeded onto a tissue engineered scaffold, PLAGA (Poly lactic-co-glycolic acid) and control Tissue culture polystyrene (TCPS). After 7 days, SEM was performed to compare cellular adhesion to the PLAGA versus the control TCPS. Cellular morphology was evaluated using immunofluorescence staining. SEM (Scanning Electron Microscope) micrographs demonstrated that cells grew and adhered on both PLAGA and TCPS surfaces and were confluent over the entire surfaces by day 7. Immunofluorescence staining showed normal, non-stressed morphological patterns on both surfaces. This technique is promising for applications in ACL regeneration and reconstruction.

The working model for surgical retrieval, tissue digestion and isolation of the human Anterior Cruciate Ligament (hACL) derived cells is shown in Figure 1. The cells migrated from the explants and adhered to the T-25 flasks. These cells were cultured for 3 days and then were visualized under a light microscope (Figure 2). A confluent monolayer was obtained by day 7. The presence of healthy, viable cells indicated the successful retrieval and culture of hACL derived cells.
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Watch this Scientific Journal Video about Surgical Retrieval, Isolation and In vitro Expansion of Human Anterior Cruciate Ligament-derived Cells for Tissue Engineering Applications at JoVE.com

Surgical Retrieval, Isolation and In vitro Expansion of Human Anterior Cruciate Ligament-derived Cells for Tissue Engineering Applications

For future applications as a patch to repair partial tears of the Anterior Cruciate Ligament (ACL), human ACL derived cells were isolated from tissue obtained during reconstructive procedures, expanded in vitro and grown on tissue engineered scaffolds. Cellular adhesion and morphology was then performed to confirm biocompatibility on scaffold surface.

Surgical Retrieval, Isolation and In vitro Expansion of Human Anterior Cruciate Ligament-derived Cells for Tissue Engineering Applications

Injury to the ACL is a commonly encountered problem in active individuals. Even partial tears of this intra-articular knee ligament lead to biomechanical ...

surgical-retrieval-isolation-vitro-expansion-human-anterior-cruciate

Research

JoVE Journal

Bioengineering

11.4K Views.  Southern Illinois University School of Medicine. For future applications as a patch to repair partial tears of the Anterior Cruciate Ligament (ACL), human ACL derived cells were isolated from tissue obtained during reconstructive procedures, expanded in vitro and grown on tissue engineered scaffolds. Cellular adhesion and morphology was then performed to confirm biocompatibility on scaffold surface.

Video: Surgical Retrieval, Isolation and In vitro Expansion of Human Anterior Cruciate Ligament-derived Cells for Tissue Engineering Applications

Tissue Engineering of a Human 3D in vitro Tumor Test System

Cancer is one of the leading causes of death worldwide. Current therapeutic strategies are predominantly developed in 2D culture systems, which inadequately reflect physiological conditions in vivo. Biological 3D matrices provide cells an environment in which cells can self-organize, allowing the study of tissue organization and cell differentiation. Such scaffolds can be seeded with a mixture of different cell types to study direct 3D cell-cell-interactions. To mimic the 3D complexity of cancer tumors, our group has developed a 3D in vitro tumor test system.	
	Our 3D tissue test system models the in vivo situation of malignant peripheral nerve sheath tumors (MPNSTs), which we established with our decellularized porcine jejunal segment derived biological vascularized scaffold (BioVaSc). In our model, we reseeded a modified BioVaSc matrix with primary fibroblasts, microvascular endothelial cells (mvECs) and the S462 tumor cell line. For static culture, the vascular structure of the BioVaSc is removed and the remaining scaffold is cut open on one side (Small Intestinal Submucosa SIS-Muc). The resulting matrix is then fixed between two metal rings (cell crowns).	
	Another option is to culture the cell-seeded SIS-Muc in a flow bioreactor system that exposes the cells to shear stress. Here, the bioreactor is connected to a peristaltic pump in a self-constructed incubator. A computer regulates the arterial oxygen and nutrient supply via parameters such as blood pressure, temperature, and flow rate. This setup allows for a dynamic culture with either pressure-regulated pulsatile or constant flow.	
	In this study, we could successfully establish both a static and dynamic 3D culture system for MPNSTs. The ability to model cancer tumors in a more natural 3D environment will enable the discovery, testing, and validation of future pharmaceuticals in a human-like model.

Tissue Engineering of a Human 3D in vitro Tumor Test System

Methods to create human 3D tumor tissues as test systems are described. These technologies are based on a decellularized Biological Vascularized Scaffold (BioVaSc), primary human cells and a tumor cell line, which can be cultured under static as well as under dynamic conditions in a flow bioreactor.

Cancer is one of the leading causes of death worldwide.  Current therapeutic strategies are predominantly developed in 2D culture  systems, which ...

Athymic Rat Model for Evaluation of Engineered Anterior Cruciate Ligament Grafts

Anterior cruciate ligament (ACL) rupture is a common ligamentous injury that often requires surgery because the ACL does not heal well without intervention. Current treatment strategies include ligament reconstruction with either autograft or allograft, which each have their associated limitations. Thus, there is interest in designing a tissue-engineered graft for use in ACL reconstruction. We describe the fabrication of an electrospun polymer graft for use in ACL tissue engineering. This polycaprolactone graft is biocompatible, biodegradable, porous, and is comprised of aligned fibers. Because an animal model is necessary to evaluate such a graft, this paper describes an intra-articular athymic rat model of ACL reconstruction that can be used to evaluate engineered grafts, including those seeded with xenogeneic cells. Representative histology and biomechanical testing results at 16 weeks postoperatively are presented, with grafts tested immediately post-implantation and contralateral native ACLs serving as controls. The present study provides a reproducible animal model with which to evaluate tissue engineered ACL grafts, and demonstrates the potential of a regenerative medicine approach to treatment of ACL rupture.

Animal models are important tools for the evaluation of tissue-engineered grafts. This paper presents the protocol for preparing an electrospun biodegradable polymer graft for use in anterior cruciate ligament tissue engineering, as well as a surgical protocol for implantation in a rat model.

Anterior cruciate ligament (ACL) rupture is a common ligamentous injury that often requires surgery because the ACL does not heal well without ...

Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and accurate assessment of ocular toxicity in man are needed. To address this need, we have developed an eye irritation test (EIT) which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model that is based on normal human cells. The EIT is able to separate ocular&#160;irritants and corrosives (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category). The test utilizes two separate protocols, one designed for liquid chemicals and a second, similar protocol for solid test articles. The EIT prediction model uses a single exposure period (30 min for liquids, 6 hr for solids) and a single tissue viability cut-off (60.0% as determined by the MTT assay). Based on the results for 83 chemicals (44 liquids and 39 solids) EIT achieved 95.5/68.2/ and 81.8% sensitivity/specificity and accuracy (SS&#38;A) for liquids, 100.0/68.4/ and 84.6% SS&#38;A for solids, and 97.6/68.3/ and 83.1% for overall SS&#38;A. The EIT will contribute significantly to classifying the ocular irritation potential of a wide range of liquid and solid chemicals without the use of animals to meet regulatory testing requirements. The EpiOcular EIT method was implemented in 2015 into the OECD Test Guidelines as TG 492.

Eye Irritation Test EIT for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial RhCE Tissue Model

We have developed an eye irritation test which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model. The test is able to discriminate between ocular irritant and corrosive materials (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category).

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and ...

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

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

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

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

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

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 ...

Isolation of Mesenchymal Stem Cells from Human Alveolar Periosteum and Effects of Vitamin D on Osteogenic Activity of Periosteum-derived Cells

Mesenchymal stem cells (MSCs) are present in a variety of tissues and can be differentiated into numerous cell types, including osteoblasts. Among the dental sources of MSCs, the periosteum is an easily accessible tissue, which has been identified to contain MSCs in the cambium layer. However, this source has not yet been widely studied.
Vitamin D3 and 1,25-(OH)2D3 have been demonstrated to stimulate in vitro differentiation of MSCs into osteoblasts. In addition, vitamin C facilitates collagen formation and bone cell growth. However, no study has yet investigated the effects of Vitamin D3 and Vitamin C on MSCs.
Here, we present a method of isolating MSCs from human alveolar periosteum and examine the hypothesis that 1,25-(OH)2D3 may exert an osteoinductive effect on these cells. We also investigate the presence of MSCs in the human alveolar periosteum and assess stem cell adhesion and proliferation. To assess the ability of vitamin C (as a control) and various concentrations of 1,25-(OH)2D3 (10&#8722;10, 10&#8722;9, 10&#8722;8, and 10&#8722;7 M) to alter key mRNA biomarkers in isolated MSCs mRNA expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), core binding factor alpha-1 (CBFA1), collagen-1, and osteocalcin (OCN) are measured using real-time polymerase chain reaction (RT-PCR).

We present a protocol to investigate the mRNA expression biomarkers of periosteum-derived cells (PDCs) induced by vitamin C (vitamin C) and 1,25-dihydroxy vitamin D [1,25-(OH)2D3]. In addition, we evaluate the ability of PDCs to differentiate into osteocytes, chondrocytes, and adipocytes.

Mesenchymal stem cells (MSCs) are present in a variety of tissues and can be differentiated into numerous cell types, including osteoblasts. Among the ...

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 ...

Production of Autologous Platelet-Rich Plasma for Boosting In Vitro Human Fibroblast Expansion

There is currently great clinical interest in the use of autologous fibroblasts for skin repair. In most cases, culture of skin cells in vitro is required. However, cell culture using xenogenic or allogenic culture media has some disadvantages (i.e., risk of infectious agent transmission or slow cell expansion). Here, an autologous culture system is developed for the expansion of human skin fibroblast cells in vitro using a patient&#8217;s own platelet-rich plasma (PRP). Human dermal fibroblasts are isolated from the patient while undergoing abdominoplasty. Cultures are followed for up to 7 days using a medium supplemented with either fetal bovine serum (FBS) or PRP. Blood cell content in PRP preparations, proliferation, and fibroblast differentiation are assessed. This protocol describes the method for obtaining a standardized, non-activated preparation of PRP using a dedicated medical device. The preparation requires only a medical device (CuteCell-PRP) and centrifuge. This device is suitable under sufficient medical practice conditions and is a one-step, apyrogenic, and sterile closed system that requires a single, soft spin centrifugation of 1,500 x g for 5 min. After centrifugation, the blood components are separated, and the platelet-rich plasma is easily collected. This device allows a quick, consistent, and standardized preparation of PRP that can be used as a cell culture supplement for in vitro expansion of human cells. The PRP obtained here contains a 1.5-fold platelet concentration compared to whole blood together, with a preferential removal of red and white blood cells. It is shown that PRP presents a boosting effect in cell proliferation compared to FBS (7.7x) and that fibroblasts are activated upon PRP treatment.

This protocol presents a device that produces PRP to boost the in vitro expansion of cells in a 100% autologous fibroblast culture system.

There is currently great clinical interest in the use of autologous fibroblasts for skin repair. In most cases, culture of skin cells in vitro is ...

Anterior Segment Organ Culture Platform for Tracking Open Globe Injuries and Therapeutic Performance

Open globe injuries have poor visual outcomes, often resulting in permanent loss of vision. This is partly due to an extended delay between injury and medical intervention in rural environments and military medicine applications where ophthalmic care is not readily available. Untreated injuries are susceptible to infection after the eye has lost its watertight seal, as well as loss of tissue viability due to intraocular hypotension. Therapeutics to temporarily seal open globe injuries, if properly developed, may be able to restore intraocular pressure and prevent infection until proper ophthalmic care is possible. To facilitate product development, detailed here is the use of an anterior segment organ culture open globe injury platform for tracking therapeutic performance for at least 72 h post-injury. Porcine anterior segment tissue can be maintained in custom-designed organ culture dishes and held at physiological intraocular pressure. Puncture injuries can be created with a pneumatic-powered system capable of generating injury sizes up to 4.5 mm in diameter, similar to military-relevant injury sizes. Loss of intraocular pressure can be observed for 72 h post-injury confirming proper injury induction and loss of the eye&#39;s watertight seal. Therapeutic performance can be tracked by application to the eye after injury induction and then tracking intraocular pressure for multiple days. Further, the anterior segment injury model is applicable to widely used methods for functionally and biologically tracking anterior segment physiology, such as assessing transparency, ocular mechanics, corneal epithelium health, and tissue viability. Overall, the method described here is a necessary next step toward developing biomaterial therapeutics for temporarily sealing open globe injuries when ophthalmic care is not readily available.

Open globe eye injuries may go untreated for multiple days in rural or military-relevant scenarios, resulting in blindness. Therapeutics are needed to minimize loss of vision. Here, we detail an organ culture open globe injury model. With this model, potential therapeutics for stabilizing these injuries can be properly evaluated.

Open globe injuries have poor visual outcomes, often resulting in permanent loss of vision. This is partly due to an extended delay between injury and ...

Fibroblast Derived Human Engineered Connective Tissue for Screening Applications

Fibroblasts are phenotypically highly dynamic cells, which quickly transdifferentiate into myofibroblasts in response to biochemical and biomechanical stimuli. The current understanding of fibrotic processes, including cardiac fibrosis, remains poor, which hampers the development of new anti-fibrotic therapies. Controllable and reliable human model systems are crucial for a better understanding of fibrosis pathology. This is a highly reproducible and scalable protocol to generate engineered connective tissues (ECT) in a 48-well casting plate to facilitate studies of fibroblasts and the pathophysiology of fibrotic tissue in a 3-dimensional (3D) environment. ECT are generated around the poles with tunable stiffness, allowing for studies under a defined biomechanical load. Under the defined loading conditions, phenotypic adaptations controlled by cell-matrix interactions can be studied. Parallel testing is feasible in the 48-well format with the opportunity for the time-course analysis of multiple parameters, such as tissue compaction and contraction against the load. From these parameters, biomechanical properties such as tissue stiffness and elasticity can be studied.

Presented here is a protocol to generate engineered connective tissues for a parallel culture of 48 tissues in a multi-well plate with double poles, suitable for mechanistic studies, disease modeling, and screening applications. The protocol is compatible with fibroblasts from different organs and species and is exemplified here with human primary cardiac fibroblasts.

Fibroblasts are phenotypically highly dynamic cells, which quickly transdifferentiate into myofibroblasts in response to biochemical and biomechanical ...