Comparison between Different Methods for Biomechanical Assessment of Ex Vivo Fracture Callus Stiffness in Small Animal Bone Healing Studies

Non-union bone fracture occurs in 5-10% of fracture injuries. Interventions include surgery with local implantation of autograft, allograft, demineralized bone matrix, and/or bone morphogenetic proteins. These types of fracture injuries are also accompanied by acute and chronic pain states. In most instances, opioids are provided to injured patients during and after surgery. With the opioid crisis, identifying new analgesic therapies that could reduce or eliminate opioid use, while also improving bone healing is important. Here we show the ability of a novel compound, MAK123, to both enhance bone healing and reduce pain behavior in a surgically induced femoral fracture mouse model. Briefly, 20 male C57BL/6 mice underwent a surgically induced femoral fracture and then were treated with 0, 2, 6, or 20 mg/kg, 3X/week for the 3 week study duration. Weekly X-rays were used to examine healing progression. Prior to euthanasia, mice underwent behavioral testing to measure evoked pain behaviors. Upon euthanasia, ex vivo µCT imaging and analysis was completed to assess fracture callus size and composition. While all doses of MAK123 tested resulted in improved healing, the 6mg/kg dose resulted in accelerated bone healing and a significant increase in mineralized callus volume (p<0.05). Similarly, while all doses of MAK123 reduced evoked responses to tactile stimulus as demonstrated by increased paw withdrawal thresholds, 6 mg/kg of MAK123 resulted in a more robust and significant improvement (p<0.05). We postulate that optimization of the dosing schedule/concentration could further improve both bone healing and behavioral measures thought to represent pain in rodents. That said, these promising pre-clinical data warrant further evaluation as MAK123 may prove to be a unique tool for orthopaedic surgery usage whereby it could both improve bone healing and reduce clinical pain, improving overall patient outcomes.

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Bone Healing Evaluation Following Different Osteotomic Techniques in Animal Models: A Suitable Method for Clinical Insights

Applied Sciences ◽

10.3390/app10207165 ◽

2020 ◽

Vol 10 (20) ◽

pp. 7165

Author(s):

Alexandre Anesi ◽

Mattia Di Bartolomeo ◽

Arrigo Pellacani ◽

Marzia Ferretti ◽

Francesco Cavani ◽

...

Keyword(s):

Elevated Temperature ◽

Animal Models ◽

Bone Healing ◽

Ex Vivo ◽

Trauma Surgery ◽

Mechanical Damage ◽

Bone Drilling ◽

Animal Bone ◽

Piezoelectric Devices

Osteotomy is a common step in oncological, reconstructive, and trauma surgery. Drilling and elevated temperature during osteotomy produce thermal osteonecrosis. Heat and associated mechanical damage during osteotomy can impair bone healing, with consequent failure of fracture fixation or dental implants. Several ex vivo studies on animal bone were recently focused on heating production during osteotomy with conventional drill and piezoelectric devices, particularly in endosseous dental implant sites. The current literature on bone drilling and osteotomic surface analysis is here reviewed and the dynamics of bone healing after osteotomy with traditional and piezoelectric devices are discussed. Moreover, the methodologies involved in the experimental osteotomy and clinical studies are compared, focusing on ex vivo and in vivo findings.

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Small animal bone healing models: Standards, tips, and pitfalls results of a consensus meeting

Bone ◽

10.1016/j.bone.2011.07.007 ◽

2011 ◽

Vol 49 (4) ◽

pp. 591-599 ◽

Cited By ~ 95

Author(s):

T. Histing ◽

P. Garcia ◽

J.H. Holstein ◽

M. Klein ◽

R. Matthys ◽

...

Keyword(s):

Bone Healing ◽

Small Animal ◽

Consensus Meeting ◽

Animal Bone

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Gene therapy for bone healing

Expert Reviews in Molecular Medicine ◽

10.1017/s1462399410001493 ◽

2010 ◽

Vol 12 ◽

Cited By ~ 52

Author(s):

Christopher H. Evans

Keyword(s):

Gene Therapy ◽

Gene Transfer ◽

Bone Healing ◽

Viral Vectors ◽

Ex Vivo ◽

Small Animal ◽

Delayed Union ◽

Bone Morphogenetic Protein 2 ◽

Toxicological Studies

Clinical problems in bone healing include large segmental defects, spinal fusions, and the nonunion and delayed union of fractures. Gene-transfer technologies have the potential to aid healing by permitting the local delivery and sustained expression of osteogenic gene products within osseous lesions. Key questions for such an approach include the choice of transgene, vector and gene-transfer strategy. Most experimental data have been obtained using cDNAs encoding osteogenic growth factors such as bone morphogenetic protein-2 (BMP-2), BMP-4 and BMP-7, in conjunction with both nonviral and viral vectors using in vivo and ex vivo delivery strategies. Proof of principle has been convincingly demonstrated in small-animal models. Relatively few studies have used large animals, but the results so far are encouraging. Once a reliable method has been developed, it will be necessary to perform detailed pharmacological and toxicological studies, as well as satisfy other demands of the regulatory bodies, before human clinical trials can be initiated. Such studies are very expensive and often protracted. Thus, progress in developing a clinically useful gene therapy for bone healing is determined not only by scientific considerations, but also by financial constraints and the ambient regulatory environment.

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Numerical Analysis of a Flexible Dual Loop Coil and its Experimental Validation for pre-Clinical Magnetic Resonance Imaging of Rodents at 7 T

Measurement Science Review ◽

10.1515/msr-2016-0037 ◽

2016 ◽

Vol 16 (6) ◽

pp. 294-299 ◽

Cited By ~ 1

Author(s):

S. Solis-Najera ◽

F. Vazquez ◽

R. Hernandez ◽

O. Marrufo ◽

A.O. Rodriguez

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Imaging System ◽

Ex Vivo ◽

Small Animal ◽

Magnetic Resonance Imaging System ◽

External Diameter ◽

Rf Coil ◽

Resonance Imaging ◽

Clinical Magnetic Resonance Imaging

Abstract A surface radio frequency coil was developed for small animal image acquisition in a pre-clinical magnetic resonance imaging system at 7 T. A flexible coil composed of two circular loops was developed to closely cover the object to be imaged. Electromagnetic numerical simulations were performed to evaluate its performance before the coil construction. An analytical expression of the mutual inductance for the two circular loops as a function of the separation between them was derived and used to validate the simulations. The RF coil is composed of two circular loops with a 5 cm external diameter and was tuned to 300 MHz and 50 Ohms matched. The angle between the loops was varied and the Q factor was obtained from the S11 simulations for each angle. B1 homogeneity was also evaluated using the electromagnetic simulations. The coil prototype was designed and built considering the numerical simulation results. To show the feasibility of the coil and its performance, saline-solution phantom images were acquired. A correlation of the simulations and imaging experimental results was conducted showing a concordance of 0.88 for the B1 field. The best coil performance was obtained at the 90° aperture angle. A more realistic phantom was also built using a formaldehyde-fixed rat phantom for ex vivo imaging experiments. All images showed a good image quality revealing clearly defined anatomical details of an ex vivo rat.

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In VivoVisualization of Heterogeneous Intratumoral Distribution of Hypoxia-Inducible Factor-1αActivity by the Fusion of High-Resolution SPECT and Morphological Imaging Tests

Journal of Biomedicine and Biotechnology ◽

10.1155/2012/262741 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 6

Author(s):

Hirofumi Fujii ◽

Masayuki Yamaguchi ◽

Kazumasa Inoue ◽

Yasuko Mutou ◽

Masashi Ueda ◽

...

Keyword(s):

High Resolution ◽

Ex Vivo ◽

Hypoxia Inducible Factor ◽

Chimeric Protein ◽

Small Animal ◽

Ct Scanner ◽

Heterogeneous Distribution ◽

Fusion Images ◽

Intratumoral Distribution

Purpose. We aimed to clearly visualize heterogeneous distribution of hypoxia-inducible factor 1α(HIF) activity in tumor tissuesin vivo.Methods. We synthesized of125I-IPOS, a125I labeled chimeric protein probe, that would visualize HIF activity. The biodistribution of125I-IPOS in FM3A tumor-bearing mice was evaluated. Then, the intratumoral localization of this probe was observed by autoradiography, and it was compared with histopathological findings. The distribution of125I-IPOS in tumors was imaged by a small animal SPECT/CT scanner. The obtainedin vivoSPECT-CT fusion images were compared withex vivoimages of excised tumors. Fusion imaging with MRI was also examined.Results.125I-IPOS well accumulated in FM3A tumors. The intratumoral distribution of125I-IPOS by autoradiography was quite heterogeneous, and it partially overlapped with that of pimonidazole. High-resolution SPECT-CT fusion images successfully demonstrated the heterogeneity of125I-IPOS distribution inside tumors. SPECT-MRI fusion images could give more detailed information about the intratumoral distribution of125I-IPOS.Conclusion. High-resolution SPECT images successfully demonstrated heterogeneous intratumoral distribution of125I-IPOS. SPECT-CT fusion images, more favorably SPECT-MRI fusion images, would be useful to understand the features of heterogeneous intratumoral expression of HIF activityin vivo.

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In Vivo Imaging of Peripheral Benzodiazepine Receptors in Mouse Lungs: A Biomarker of Inflammation

Molecular Imaging ◽

10.2310/7290.2005.05133 ◽

2005 ◽

Vol 4 (4) ◽

pp. 7290.2005.05133 ◽

Cited By ~ 19

Author(s):

Matthew J. Hardwick ◽

Ming-Kai Chen ◽

Kwamena Baidoo ◽

Martin G. Pomper ◽

Tomás R. Guilarte

Keyword(s):

In Vivo Imaging ◽

Ex Vivo ◽

Inflammatory Diseases ◽

Imaging Techniques ◽

Benzodiazepine Receptors ◽

Small Animal ◽

Small Animal Pet ◽

Planar Imaging ◽

Peripheral Benzodiazepine Receptors

The ability to visualize the immune response with radioligands targeted to immune cells will enhance our understanding of cellular responses in inflammatory diseases. Peripheral benzodiazepine receptors (PBR) are present in monocytes and neutrophils as well as in lung tissue. We used lipopolysaccharide (LPS) as a model of inflammation to assess whether the PBR could be used as a noninvasive marker of inflammation in the lungs. Planar imaging of mice administrated 10 or 30 mg/kg LPS showed increased [123I]-( R)-PK11195 radioactivity in the thorax 2 days after LPS treatment relative to control. Following imaging, lungs from control and LPS-treated mice were harvested for ex vivo gamma counting and showed significantly increased radioactivity above control levels. The specificity of the PBR response was determined using a blocking dose of nonradioactive PK11195 given 30 min prior to radiotracer injection. Static planar images of the thorax of nonradioactive PK11195 pretreated animals showed a significantly lower level of radiotracer accumulation in control and in LPS-treated animals ( p < .05). These data show that LPS induces specific increases in PBR ligand binding in the lungs. We also used in vivo small-animal PET studies to demonstrate increased [11C]-( R)-PK11195 accumulation in the lungs of LPS-treated mice. This study suggests that measuring PBR expression using in vivo imaging techniques may be a useful biomarker to image lung inflammation.

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Coregistration of Small Animal PET and Autoradiography for in vivo–ex vivo Comparison

Lecture Notes in Computer Science - Progress in Pattern Recognition, Image Analysis and Applications ◽

10.1007/978-3-540-76725-1_85 ◽

2007 ◽

pp. 822-830

Author(s):

Soo-Min Song ◽

Min-Jeong Kim ◽

Joung-Min Lee ◽

Hye-Jin Park ◽

KyeongMin Kim ◽

...

Keyword(s):

Ex Vivo ◽

Small Animal ◽

Small Animal Pet ◽

Animal Pet

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Abstract 1767: Feasibility of In Vivo Cardiac Stem Cell Tracking, by SPECT and PET Imaging, Using the Sodium-iodide Symporter as Reporter Gene

Circulation ◽

10.1161/circ.116.suppl_16.ii_374 ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

John Terrovitis ◽

Keng Fai Kwok ◽

Riikka Läutamaki ◽

James M Engles ◽

Andreas S Barth ◽

...

Keyword(s):

Stem Cell ◽

Reporter Gene ◽

Cell Tracking ◽

Ex Vivo ◽

Small Animal ◽

Cell Labeling ◽

Sodium Iodide Symporter ◽

Cell Injection

Background. Stem cells offer the promise of cardiac repair. Stem cell labeling is a prerequisite to tracking cell fate in vivo . Aim. To develop a reporter gene that permits in vivo stem cell labeling. We examined the sodium-iodide symporter (NIS), a protein that is not expressed in the heart, but promotes cellular uptake of 99m Tc or 124 I, thus permitting cell tracking by SPECT or PET imaging, respectively. Methods. The human NIS gene ( h NIS) was expressed in rat cardiac derived stem cells (rCDCs) using lentivirus driven by the CAG or CMV promoter. NIS function in transduced cells was confirmed by in vitro 99m Tc uptake. Eleven rats were injected with 1 or 2 million rCDCs intramyocardially immediately after LAD ligation; 6 with CMV-NIS and 5 with CAG-NIS cells. Dual isotope SPECT imaging was performed on a small animal SPECT/CT system, using 99m Tc for cell detection and 201 Tl for myocardial delineation, 24 hrs after cell injection. PET was performed on a small animal PET scanner using 124 I for cell tracking and 13 NH 3 for myocardial delineation, 48hrs after cell injection. Contrast Ratio (CR) was defined as [(signal in the cells)-(signal in blood pool)]/signal in blood pool. High resolution ex vivo SPECT scans of explanted hearts (n=3) were obtained to confirm that in vivo signal was derived from the cell injection site. The presence of h NIS mRNA was confirmed in injected hearts after animal sacrifice (n=2), by real-time RT-PCR. Results. NIS expression in rCDCs did not affect cell viability/proliferation (p=0.718, ctr vs NIS). In vitro 99m Tc uptake was 6.0±0.9% vs 0.07±0.05, without and with perchlorate (specific NIS blocker), respectively. NIS-transduced rCDCs were easily visualized as spots of 99m Tc or 124 I uptake within a perfusion deficit in the SPECT and PET images. CR was considerably higher when cells were transduced by the CMV-NIS virus in comparison to the CAG-NIS virus (70±40% vs 28±29%, p=0.085). Ex vivo small animal SPECT imaging confirmed that in vivo 99m Tc signals were localized to the injection sites. PCR confirmed the presence of h NIS mRNA in injected hearts. Conclusion. NIS expression allows non invasive in vivo stem cell tracking in the myocardium, using both SPECT and PET. This reporter gene has great potential for translation in future clinical applications.

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