scholarly journals A Second Generation Mn-Porphyrin Dimer with a Twisted Linker as a Potential Blood Pool Agent for MRI: Tuning the Geometry and Binding with HSA

2020 ◽  
Vol 13 (10) ◽  
pp. 282
Author(s):  
Hanlin Liu ◽  
Weiran Cheng ◽  
Shili Dong ◽  
David Feng Xu ◽  
Keith Tang ◽  
...  
Keyword(s):  
Vascular System ◽  
Time Window ◽  
Molecular Geometry ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Mri Contrast ◽  
Vis Spectroscopy ◽  
Blood Pool Agents ◽  
Chemical Strategy

Blood-pool agents (BPAs) are MRI contrast agents (CAs) characterized by their long circulation in the vascular system to provide an extended time window for high-resolution MR angiography (MRA). Prolonged vascular retention, however, impedes the excretion of BPAs. Therefore, chemical strategy to regulate the balance between retention and clearance is important to reach optimal pharmacokinetics. We recently developed MnP2, the first Mn(III)-porphyrin (MnP) based BPA. MnP2 shows high T1 relaxivity (r1) and high affinity to human serum albumin (HSA) that leads to up to 48-h vascular retention in rats. However, upon albumin binding, the r1 is decreased. To modulate vascular retention time and plasma r1, a regioisomer of MnP2, m-MnP2, was synthesized. The free m-MnP2 exhibits lower r1 than that of MnP2 at magnetic fields above 2 MHz, which agrees with their relative hydrodynamic sizes. The HSA binding of m-MnP2 was evaluated using UV-Vis spectroscopy and found to have tuned-down affinity in comparison with MnP2. Upon HSA binding, the protein complex of m-MnP2 exhibits an r1 of 11.8 mM−1 s−1 at 3 T, which is higher than that of MnP2 bound to HSA. Taken together, this demonstrated the role of molecular geometry in optimizing the pharmacokinetics of albumin-targeting BPAs.

scholarly journals Biological effects of MRI contrast agents: gadolinium retention, potential mechanisms and a role for phosphorus

2017 ◽  
Vol 375 (2107) ◽  
pp. 20170180 ◽  
Author(s):  
Joel Garcia ◽  
Stephen Z. Liu ◽  
Angelique Y. Louie
Keyword(s):  
Molecular Imaging ◽  
Contrast Agents ◽  
Biological Effects ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Mri Contrast ◽  
Treatment Regimens ◽  
Gadolinium Retention ◽  
Magnetic Resonance Imaging Mri ◽  
Blood Pool Agents

No discussion of challenges for chemistry in molecular imaging would be complete without addressing the elephant in the room—which is that the purest of chemical compounds needs to interact with a biological system in a manner that does not perturb normal biology while still providing efficacious feedback to assist in diagnosis of disease. In the past decade, magnetic resonance imaging (MRI) agents long considered inert have produced adverse effects in certain patient populations under certain treatment regimens. More recently, inert blood pool agents have been found to deposit in the brain. Release of free metal is often suspected as the culprit but that hypothesis has yet to be validated. In addition, even innocuous agents can cause painful side effects during injection in some patients. In this brief review, we summarize known biological effects for gadolinium- and iron-based MRI contrast agents, and discuss some of the potential mechanisms for the observed biological effects, including the potential role of phosphorus imbalance, related to kidney disease or cancer, in destabilizing gadolinium-based chelates and precipitating free gadolinium. This article is part of the themed issue ‘Challenges for chemistry in molecular imaging’.

scholarly journals Albumin-binding MR blood pool agents as MRI contrast agents in an intracranial mouse glioma model

2003 ◽  
Vol 49 (3) ◽  
pp. 586-590 ◽  
Author(s):  
Kofi Adzamli ◽  
Dmitriy A. Yablonskiy ◽  
Michael R. Chicoine ◽  
Eun Kyung Won ◽  
Karen P. Galen ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Albumin Binding ◽  
Mri Contrast ◽  
Glioma Model ◽  
Blood Pool Agents ◽  
Mouse Glioma

The Role of Water Exchange in Attaining Maximum Relaxivities for Dendrimeric MRI Contrast Agents

1996 ◽  
Vol 2 (12) ◽  
pp. 1607-1615 ◽  
Author(s):  
Éva Tóth ◽  
Dirk Pubanz ◽  
Sylvain Vauthey ◽  
Lothar Helm ◽  
André E. Merbach
Keyword(s):  
Contrast Agents ◽  
Water Exchange ◽  
Mri Contrast Agents ◽  
Mri Contrast

Blood-Pool and Targeting MRI Contrast Agents: From Gd-Chelates to Gd-Nanoparticles

2012 ◽  
Vol 2012 (12) ◽  
pp. 1924-1933 ◽  
Author(s):  
Gang Ho Lee ◽  
Yongmin Chang ◽  
Tae-Jeong Kim
Keyword(s):  
Contrast Agents ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Mri Contrast

scholarly journals A Photocleavable Contrast Agent for Light-Responsive MRI

2020 ◽  
Vol 13 (10) ◽  
pp. 296
Author(s):  
Friederike Reeßing ◽  
Sèvrin E. M. Huijsse ◽  
Rudi A. J. O. Dierckx ◽  
Ben L. Feringa ◽  
Ronald J.H. Borra ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
Whole Body ◽  
Spatiotemporal Resolution ◽  
Mri Contrast ◽  
High Relaxivity ◽  
Vis Spectroscopy ◽  
Clinical Mri

Thanks to its innocuousness and high spatiotemporal resolution, light is used in several established and emerging applications in biomedicine. Among them is the modulation of magnetic resonance imaging (MRI) contrast agents’ relaxivity with the aim to increase the sensitivity, selectivity and amount of functional information obtained from this outstanding whole-body medical imaging technique. This approach requires the development of molecular contrast agents that show high relaxivity and strongly pronounced photo-responsiveness. To this end, we report here the design and synthesis of a light-activated MRI contrast agent, together with its evaluation using UV–vis spectroscopy, Fast Field Cycling (FFC) relaxometry and relaxometric measurements on clinical MRI scanners. The high relaxivity of the reported agent changes substantially upon irradiation with light, showing a 17% decrease in relaxivity at 0.23T upon irradiation with λ = 400 nm (violet) light for 60 min. On clinical MRI scanners (1.5T and 3.0T), irradiation leads to a decrease in relaxivity of 9% and 19% after 3 and 60 min, respectively. The molecular design presents an important blueprint for the development of light-activatable MRI contrast agents.

Gadolinium-bearing red cells as blood pool MRI contrast agents

1998 ◽  
Vol 40 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Kevin M. Johnson ◽  
Jing Zang Tao ◽  
Richard P. Kennan ◽  
John C. Gore
Keyword(s):  
Contrast Agents ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Red Cells ◽  
Mri Contrast

The Gadonanotubes as High-Performance MRI Contrast Agents: The Unappreciated Role of the Carbon Nanotube Component at Low Magnetic Fields

2017 ◽  
Vol 6 (6) ◽  
pp. M3173-M3180 ◽  
Author(s):  
Sakineh E. Moghaddam ◽  
Richa Sethi ◽  
Farzaneh Shayeganfar ◽  
Robert G. Bryant ◽  
Lon J. Wilson
Keyword(s):  
Carbon Nanotube ◽  
Magnetic Fields ◽  
Contrast Agents ◽  
High Performance ◽  
Mri Contrast Agents ◽  
Mri Contrast

scholarly journals Intravascular (blood pool) MRI contrast agents

2013 ◽  
Author(s):  
Andrew Murphy ◽  
J. Ballinger
Keyword(s):  
Contrast Agents ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Mri Contrast

scholarly journals Dendrimer-based Macromolecular MRI Contrast Agents: Characteristics and Application

2003 ◽  
Vol 2 (1) ◽  
pp. 153535002003031 ◽  
Author(s):  
Hisataka Kobayashi ◽  
Martin W. Brechbiel
Keyword(s):  
Contrast Agents ◽  
Neutron Capture ◽  
Molecular Size ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Neutron Capture Therapy ◽  
Mri Contrast ◽  
Therapeutic Drugs ◽  
General Potential ◽  
Lymphatic Imaging

Numerous macromolecular MRI contrast agents prepared employing relatively simple chemistry may be readily available that can provide sufficient enhancement for multiple applications. These agents operate using a ~100-fold lower concentration of gadolinium ions in comparison to the necessary concentration of iodine employed in CT imaging. Herein, we describe some of the general potential directions of macromolecular MRI contrast agents using our recently reported families of dendrimer-based agents as examples. Changes in molecular size altered the route of excretion. Smaller-sized contrast agents less than 60 kDa molecular weight were excreted through the kidney resulting in these agents being potentially suitable as functional renal contrast agents. Hydrophilic and larger-sized contrast agents were found better suited for use as blood pool contrast agents. Hydrophobic variants formed with polypropylenimine diaminobutane dendrimer cores created liver contrast agents. Larger hydrophilic agents are useful for lymphatic imaging. Finally, contrast agents conjugated with either monoclonal antibodies or with avidin are able to function as tumor-specific contrast agents, which also might be employed as therapeutic drugs for either gadolinium neutron capture therapy or in conjunction with radioimmunotherapy.

ChemInform Abstract: Blood-Pool and Targeting MRI Contrast Agents: From Gd-Chelates to Gd-Nanoparticles

ChemInform ◽  
2012 ◽  
Vol 43 (29) ◽  
pp. no-no
Author(s):  
Gang Ho Lee ◽  
Yongmin Chang ◽  
Tae-Jeong Kim
Keyword(s):  
Contrast Agents ◽  
Blood Pool ◽  
Mri Contrast Agents ◽  
Mri Contrast
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