scholarly journals Administration of a VEGFR‑2-specific MRI contrast agent to assess orthodontic tooth movement

2021 ◽  
Author(s):  
Agnes Schröder ◽  
Lisa Seyler ◽  
Elisabeth Hofmann ◽  
Lina Gölz ◽  
Jonathan Jantsch ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Contralateral Side ◽  
Mri Contrast Agent ◽  
Washout Rate ◽  
Mri Contrast ◽  
Imaging Protocol ◽  
Dce Mri

Abstract Purpose It is thought that orthodontic forces initially reduce periodontal blood flow during orthodontic tooth movement (OTM) via tissue compression with cells responding to concomitant oxygen deprivation with expression of vascular endothelial growth factor (VEGF) triggering angiogenesis via binding to its receptor VEGFR‑2. To test this hypothesis, we performed a pilot study to establish a protocol for molecular magnetic resonance imaging (MRI) of rat jaws administering a VEGFR-2-specific contrast agent. Methods Mesial OTM of a first upper left rat molar was initiated in one male Fischer 344 rat 4 days prior to MRI by insertion of an elastic band between the first and second upper molars with the contralateral side left untreated (internal control). T1-weighted MRI sequences including dynamic contrast-enhanced MRI (DCE-MRI) were recorded before and after administration of a molecular VEGFR‑2 MRI marker with a 7 T MRI dedicated for small animal use. Results After injection of anti-VEGFR2-albumin-gadolinium-DTPA, volume enhancement on T1-weighted images was increased at the OTM side distally of the moved first upper molar (M1) compared to the control side, whereas the T1 relaxation time was reduced on the OTM side. DCE-MRI resulted in an increased area under the curve (AUC), whereas time-to-peak (TTP) and washout rate were reduced during OTM distally of the moved M1 compared to the contralateral side. Conclusions OTM resulted in uptake of the VEGFR-2-specific MRI contrast agent in tension areas of the periodontal ligament. The imaging protocol presented here is useful for the assessment of VEGFR‑2 expression in tension areas of the periodontal ligament in vivo.

scholarly journals Molecular Markers of Early Orthodontic Tooth Movement

2009 ◽  
Vol 79 (6) ◽  
pp. 1108-1113 ◽  
Author(s):  
Patricia Joyce Brooks ◽  
Dorrin Nilforoushan ◽  
Morris Frank Manolson ◽  
Craig A. Simmons ◽  
Siew-Ging Gong
Keyword(s):  
Periodontal Ligament ◽  
Tooth Movement ◽  
Early Stage ◽  
Expression Patterns ◽  
Orthodontic Tooth Movement ◽  
Contralateral Side ◽  
Tooth Root ◽  
Ki 67 ◽  
Related Transcription Factor ◽  
Osteoclastic Differentiation

Abstract Objective: To understand the molecular basis of early orthodontic tooth movement by looking at the expression of KI-67, runt-related transcription factor 2 (Runx2), and tumor necrosis factor ligand superfamily member 11 (RANKL) proteins. Materials and Methods: We employed a rat model of early orthodontic tooth movement using a split-mouth design (where contralateral side serves as a control) and performed immunohistochemical staining to map the spatial expression patterns of three proteins at 3 and 24 hours after appliance insertion. Results: We observed increased expression of KI-67, a proliferation marker, and RANKL, a molecule associated with osteoclastic differentiation, in the compression sites of the periodontal ligament subjected to 3 hours of force. In contrast, there was increased expression of KI-67 and Runx2, a marker of osteoblast precursors, in tension areas after 24 hours of force. Decreased KI-67 expression in the mesial and distal regions of the periodontal ligament was observed at the midpoint of the tooth root. Conclusions: The early RANKL expression indicates that at this early stage cells are involved in osteoclast precursor signaling. Also, decreased KI-67 expression found near the midpoint of the tooth root is believed to represent the center of rotation, providing a molecular means of visualizing mechanical loading patterns.

SU-D-18C-04: The Feasibility of Quantifying MRI Contrast Agent in Pulsatile Flowing Blood Using DCE-MRI

2014 ◽  
Vol 41 (6Part4) ◽  
pp. 121-121
Author(s):  
Gwilliam M N ◽  
Collins D J ◽  
Leach M O ◽  
Orton M R
Keyword(s):  
Contrast Agent ◽  
Mri Contrast Agent ◽  
Mri Contrast ◽  
Dce Mri ◽  
Flowing Blood

scholarly journals Evaluation of non-targeting, C- or N-pH (low) insertion peptide modified superparamagnetic iron oxide nanoclusters for selective MRI of liver tumors and their potential toxicity in cirrhosis

RSC Advances ◽  
2019 ◽  
Vol 9 (25) ◽  
pp. 14051-14059
Author(s):  
Abdulrahman Ahmed Mahmood ◽  
Jianqi Zhang ◽  
Rufang Liao ◽  
Xiwei Pan ◽  
Dan Xu ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Liver Cancer ◽  
Contrast Agent ◽  
Cancer Diagnosis ◽  
Liver Tumors ◽  
Superparamagnetic Iron Oxide ◽  
Mri Contrast Agent ◽  
Potential Toxicity ◽  
Mri Contrast ◽  
Specific Enhancement

The acid-responsive pHLIP modified SPION as an MRI contrast agent for liver cancer diagnosis requires the validation of both the tumor-specific enhancement and a safe profile in cirrhosis.

scholarly journals In Vitro Compression Model for Orthodontic Tooth Movement Modulates Human Periodontal Ligament Fibroblast Proliferation, Apoptosis and Cell Cycle

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 932
Author(s):  
Julia Brockhaus ◽  
Rogerio B. Craveiro ◽  
Irma Azraq ◽  
Christian Niederau ◽  
Sarah K. Schröder ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Periodontal Ligament ◽  
Environmental Changes ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Compressive Force ◽  
Periodontal Ligament Fibroblasts ◽  
Human Periodontal Ligament Fibroblasts

Human Periodontal Ligament Fibroblasts (hPDLF), as part of the periodontal apparatus, modulate inflammation, regeneration and bone remodeling. Interferences are clinically manifested as attachment loss, tooth loosening and root resorption. During orthodontic tooth movement (OTM), remodeling and adaptation of the periodontium is required in order to enable tooth movement. hPDLF involvement in the early phase-OTM compression side was investigated for a 72-h period through a well-studied in vitro model. Changes in the morphology, cell proliferation and cell death were analyzed. Specific markers of the cell cycle were investigated by RT-qPCR and Western blot. The study showed that the morphology of hPDLF changes towards more unstructured, unsorted filaments under mechanical compression. The total cell numbers were significantly reduced with a higher cell death rate over the whole observation period. hPDLF started to recover to pretreatment conditions after 48 h. Furthermore, key molecules involved in the cell cycle were significantly reduced under compressive force at the gene expression and protein levels. These findings revealed important information for a better understanding of the preservation and remodeling processes within the periodontium through Periodontal Ligament Fibroblasts during orthodontic tooth movement. OTM initially decelerates the hPDLF cell cycle and proliferation. After adapting to environmental changes, human Periodontal Ligament Fibroblasts can regain homeostasis of the periodontium, affecting its reorganization.

Gd2O3 nanoparticles as a positive MRI contrast agent for cell uptake

2010 ◽  
Author(s):  
N. Riyahi-Alam ◽  
J. Behrouzkia ◽  
S. Haghgoo ◽  
A Seifalian ◽  
R Zohdi Aghdam. ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Mri Contrast Agent ◽  
Cell Uptake ◽  
Mri Contrast ◽  
Gd2o3 Nanoparticles

scholarly journals Myeloid HIF1α Is Involved in the Extent of Orthodontically Induced Tooth Movement

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 796
Author(s):  
Christian Kirschneck ◽  
Nadine Straßmair ◽  
Fabian Cieplik ◽  
Eva Paddenberg ◽  
Jonathan Jantsch ◽  
...  
Keyword(s):  
Bone Density ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Hypoxia Inducible Factor ◽  
Myeloid Cells ◽  
Orthodontic Tooth Movement ◽  
Periodontal Ligament Fibroblasts ◽  
Expression Of Genes ◽  
Periodontal Bone Loss

During orthodontic tooth movement, transcription factor hypoxia-inducible factor 1α (HIF1α) is stabilised in the periodontal ligament. While HIF1α in periodontal ligament fibroblasts can be stabilised by mechanical compression, in macrophages pressure application alone is not sufficient to stabilise HIF1α. The present study was conducted to investigate the role of myeloid HIF1α during orthodontic tooth movement. Orthodontic tooth movement was performed in wildtype and Hif1αΔmyel mice lacking HIF1α expression in myeloid cells. Subsequently, µCT images were obtained to determine periodontal bone loss, extent of orthodontic tooth movement and bone density. RNA was isolated from the periodontal ligament of the control side and the orthodontically treated side, and the expression of genes involved in bone remodelling was investigated. The extent of tooth movement was increased in Hif1αΔmyel mice. This may be due to the lower bone density of the Hif1αΔmyel mice. Deletion of myeloid Hif1α was associated with increased expression of Ctsk and Acp5, while both Rankl and its decoy receptor Opg were increased. HIF1α from myeloid cells thus appears to play a regulatory role in orthodontic tooth movement.

scholarly journals Biocompatibility of Bacterial Magnetosomes as MRI Contrast Agent: A Long-Term In Vivo Follow-Up Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1235
Author(s):  
Xiaohui Nan ◽  
Wenjia Lai ◽  
Dan Li ◽  
Jiesheng Tian ◽  
Zhiyuan Hu ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Magnetic Domain ◽  
Bilayer Membrane ◽  
The Body ◽  
Mri Contrast Agent ◽  
Mri Imaging ◽  
Mri Contrast

Derived from magnetotactic bacteria (MTB), magnetosomes consist of magnetite crystals enclosed within a lipid bilayer membrane and are known to possess advantages over artificially synthesized nanoparticles because of the narrow size distribution, uniform morphology, high purity and crystallinity, single magnetic domain, good biocompatibility, and easy surface modification. These unique properties have increasingly attracted researchers to apply bacterial magnetosomes (BMs) in the fields of biology and medicine as MRI imaging contrast agents. Due to the concern of biosafety, a long-term follow-up of the distribution and clearance of BMs after entering the body is necessary. In this study, we tracked changes of BMs in major organs of mice up to 135 days after intravenous injection using a combination of several techniques. We not only confirmed the liver as the well-known targeted organs of BMs, but also found that BMs accumulated in the spleen. Besides, two major elimination paths, as well as the approximate length of time for BMs to be cleared from the mice, were revealed. Together, the results not only confirm that BMs have high biocompatibility, but also provide a long-term in-vivo assessment which may further help to forward the clinical applications of BMs as an MRI contrast agent.

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