We would like to acknowledge the funding support for this work from the Canadian Institutes of Health Research (CIHR), the Krembil Family Foundation, the Halbert Chair in Neural Repair and Regeneration, Phillip and Peggy DeZwirek, and Gordon Yao for the contribution to Figure 2. Klaus Zweckberger was funded by a grant from the &#8220;Deutsche Forschungsgesellschaft&#8221; (DFG).

NOTE: The following experimental protocol was approved by the animal care committee of the University Health Network (Toronto, Canada) and is in accordance with the policies established in the guide to the care and use of experimental animals prepared by the Canadian council of animal care.
1. Cervical Aneurysm Clip Contusion/Compression Model
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Covidien supplied the QL6 SAP for this study.

This protocol has been developed to enable the reader to perform a cervical injury model in rats and to use a combined treatment approach with SAPs and NPCs promoting better recovery after cervical SCI.
Particularly in comparison to other cervical trauma models, such as the (hemi)-transection model or the weight drop and concussion models, the clip contusion/compression model represents both major pathophysiological trauma mechanisms &#8211; contusion and compression- and therefore mimics best...

More than 50% of spinal cord injuries are related to the cervical spine. In the clinical setting two major pathophysiological mechanisms are described: the initial contusion of the spinal cord and subsequently, the ongoing compression caused by bone fractures, hemorrhages or tissue swelling.
The aneurysm clip contusion/compression model mimics both pathophysiological mechanisms: snapping the clip produces a contusion and the duration of clipping represents the compression component, conceding that the compression in clinical settings caused by bone fractures, hemorrhages or tissue swelling last significant longer. The used aneurysm clip is modified by a ring spring guaranteeing exact and reproducible clipping force. Especially in comparison to the hemi-transection or the contusion model, this aneurysm clip model mimics best clinical settings. While patients with thoracic injuries suffer from paraplegia, most patients with cervical injuries are tetraplegic and completely dependent. The anatomical structure of the cervical cord, however, shows significant differences compared to the thoracic or lumbar spine, and thus, is addressed in particular in this protocol.
The development of intramedullary cavities and tissue scarring are obstacles for recovery and regeneration. To overcome these barriers the use of scaffold material is a promising approach. Self-assembling peptides can be injected directly into the epicenter of the lesion. There they assemble into nano-fiber scaffolds bridging the cavity and improve the inhibitory environment by reducing inflammation and tissue scaring. While rigid materials cause considerable damage of the spinal cord during implantation, the fluid peptides can be injected safely and without severe additional damage.
Improving the inhibitory environment with self-assembling peptides before stem cell transplantation, hence, support cell integration, differentiation and finally, functional recovery, after cervical spinal cord injury.

<table border="0" cellpadding="0" cellspacing="0" width="541">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:273px;">Name</td>
			<td style="width:268px;">Company</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Aneurysmal clip</td>
			<td>SharpTech</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Surgical microscope</td>
			<td>Leica</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micro injection system</td>
			<td>World Precision Instruments, Inc.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Small animal stereotaxic instrument</td>
			<td>David Kopf Instruments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hamilton syringe</td>
			<td>Hamilton company</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Subdural pumps</td>
			<td>Alzet osmotic micro pump 1007D</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Surgical instrument</td>
			<td>Fine Science tools</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Isoflurane USP</td>
			<td>Pharmaceutical Partners of Canada Inc.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.9% Sodium Chloride injection USP</td>
			<td>Baxter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">7.5% Povidone iodine</td>
			<td>Purdue Pharma</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">70% Isopropyl alcohol USP</td>
			<td>GreenField Ethanol Inc.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">QL6 SAP</td>
			<td>Covidien</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.4% Trypan blue</td>
			<td>Gibco</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Platelet-Derived Growth Factor (PDGF)</td>
			<td>Sigma</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Epidermal Growth Factor (EGF)</td>
			<td>Sigma</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fibroblast Growth Factor (FGF)</td>
			<td>Sigma</td>
		</tr>
	</tbody>
</table>

synergetic use of neural precursor cells and self-assembling peptides in experimental cervical spinal cord injury

Spinal cord injuries (SCI) cause serious neurological impairment and psychological, economic, and social consequences for patients and their families. Clinically, more than 50% of SCI affect the cervical spine1. As a consequence of the primary injury, a cascade of secondary mechanisms including inflammation, apoptosis, and demyelination occur finally leading to tissue scarring and development of intramedullary cavities2,3. Both represent physical and chemical barriers to cell transplantation, integration, and regeneration. Therefore, shaping the inhibitory environment and bridging cavities to create a supportive milieu for cell transplantation and regeneration is a promising therapeutic target4. Here, a contusion/compression model of cervical SCI using an aneurysm clip is described. This model is more clinically relevant than other experimental models, since complete transection or ruptures of the cord are rare. Also in comparison to the weight drop model, which in particular damage the dorsum columns, circumferential compression of the spinal cord appears advantageous. Clip closing force and duration can be adjusted to achieve different injury severity. A ring spring facilitates precise calibration and constancy of clip force. Under physiological conditions, synthetic self-assembling peptides (SAP) self-assemble into nanofibers and thus, are appealing for application in SCI5. They can be injected directly into the lesion minimizing damage to the cord. SAPs are biocompatible structures erecting scaffolds to bridge intramedullary cavities and thus, equip the damaged cord for regenerative treatments. K2(QL)6K2 (QL6) is a novel SAP introduced by Dong et al.6 In comparison to other peptides, QL6 self-assembles into &#946;-sheets at neutral pH6.14 days after SCI, after the acute stage, SAPs are injected into the center of the lesion and neural precursor cells (NPC) are injected into adjacent dorsal columns. In order to support cell survival, transplantation is combined with continuous subdural administration of growth factors by osmotic micro pumps for 7 days.

When performing the above-described procedure, you will get a SAP scaffold bridging the cavity and offering an improvement of the inhibitory environment, less tissue scaring and an increase in NPC survival. Figure 4 shows a longitudinal section of a rat spinal cord obtained at the injury site 6 weeks after SCI and 4 weeks after QL6 SAP injection and NPC transplantation. QL6 peptides were successfully injected into the cord, aggregated in the epicenter and diffused rostro-caudally in the penumbra. Electro...

Watch this Scientific Journal Video about Synergetic Use of Neural Precursor Cells and Self-assembling Peptides in Experimental Cervical Spinal Cord Injury at JoVE.com

Synergetic Use of Neural Precursor Cells and Self-assembling Peptides in Experimental Cervical Spinal Cord Injury

Treating cervical spinal cord injury with both self-assembling peptides (SAP) and neural precursor cells (NPC), together with growth factors, is a promising approach to promote regeneration and recovery. A contusion/compression aneurysm clip rat model of cervical SCI and combined treatment involving SAP injection and NPC transplantation is established.

Spinal cord injuries (SCI) cause serious neurological impairment and psychological, economic, and social consequences for patients and their families. ...

synergetic-use-neural-precursor-cells-self-assembling-peptides

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Medicine

9.1K Görüntüleme.  University Health Network, Krembil Neuroscience Centre. Treating cervical spinal cord injury with both self-assembling peptides (SAP) and neural precursor cells (NPC), together with growth factors, is a promising approach to promote regeneration and recovery. A contusion/compression aneurysm clip rat model of cervical SCI and combined treatment involving SAP injection and NPC transplantation is established. 