1 3
Topics in Current Chemistry (2020) 378:40
4.2 IONPs as CA in Other Pathologies
Although most research in IONPs designed to serve as MRI CAs is focused
on cancer diagnosis, there are many other pathologies that can benefit from
advances in this field of research, as discussed henceforth. Recent investigations
have demonstrated that an acetylcholine-sensitive mMRI nanosensor can be used
for measuring the endogenous release of acetylcholine in the rat brain after its
intracerebral administration [294]. Similarly, after intracerebral administration
of alginate-coated IONPs, changes in Ca
2+
levels have been monitored following
a quinolinic acid-induced striatal lesion [295]. Other magnetic nanostructures
have been used for the detection of brain inflammation [296]. These particular
nanostructures are based on IONPs coupled covalently through peptide linkers
that have been designed to be cleaved by the intracellular macrophage cathepsin, which results in microparticles of iron oxide (MPIO) and allows the fate
of magnetic NPs to be tracked. This is because the MPIO, once sequestered by
macrophages in the liver, decrease their relaxivity, while particles that associate
with their target tissue in the brain remain unaltered and functional.
Thrombosis is a major clinical problem whose incidence has not decreased
over the last 20 years and is involved in several pathological disorders such as
myocardial infarction, ischemic stroke or pulmonary embolism, among others
[297]. Early detection is essential for effective treatment, but it remains challenging in practice. P-selectin is an adhesion molecule, overexpressed at the surface of endothelial cells and platelets upon activation, which plays a fundamental
role in thrombus formation [298]. Based on this fact, Suzuki et al. [299] innovated a fucoidan (a natural sulfated polysaccharide with high affinity for activated platelets through P-selectin)-coated USPIONs to visualize by MRI arterial
thrombi in the early stage of the disease. Other investigations used PLGA-coated
IONs, functionalized with EWVDV peptide, which has a high affinity and specificity for P-selectin, to target thrombi for both diagnosis and treatment through
the induction of thrombolysis [300].
4.3 Other Applications
IONPs have also been used in combination with MRI for many other in vivo applications, such as imaging of activated microglia during brain inflammation [301],
tracking of stem cells [302–304], image-guided treatment of anemia using bacteria loaded with IONPs [305], or to carry out vascular imaging [306, 307], among
others.
73
Reprinted from the journal
Topics in Current Chemistry (2020) 378:40
4.2 IONPs as CA in Other Pathologies
Although most research in IONPs designed to serve as MRI CAs is focused
on cancer diagnosis, there are many other pathologies that can benefit from
advances in this field of research, as discussed henceforth. Recent investigations
have demonstrated that an acetylcholine-sensitive mMRI nanosensor can be used
for measuring the endogenous release of acetylcholine in the rat brain after its
intracerebral administration [294]. Similarly, after intracerebral administration
of alginate-coated IONPs, changes in Ca
2+
levels have been monitored following
a quinolinic acid-induced striatal lesion [295]. Other magnetic nanostructures
have been used for the detection of brain inflammation [296]. These particular
nanostructures are based on IONPs coupled covalently through peptide linkers
that have been designed to be cleaved by the intracellular macrophage cathepsin, which results in microparticles of iron oxide (MPIO) and allows the fate
of magnetic NPs to be tracked. This is because the MPIO, once sequestered by
macrophages in the liver, decrease their relaxivity, while particles that associate
with their target tissue in the brain remain unaltered and functional.
Thrombosis is a major clinical problem whose incidence has not decreased
over the last 20 years and is involved in several pathological disorders such as
myocardial infarction, ischemic stroke or pulmonary embolism, among others
[297]. Early detection is essential for effective treatment, but it remains challenging in practice. P-selectin is an adhesion molecule, overexpressed at the surface of endothelial cells and platelets upon activation, which plays a fundamental
role in thrombus formation [298]. Based on this fact, Suzuki et al. [299] innovated a fucoidan (a natural sulfated polysaccharide with high affinity for activated platelets through P-selectin)-coated USPIONs to visualize by MRI arterial
thrombi in the early stage of the disease. Other investigations used PLGA-coated
IONs, functionalized with EWVDV peptide, which has a high affinity and specificity for P-selectin, to target thrombi for both diagnosis and treatment through
the induction of thrombolysis [300].
4.3 Other Applications
IONPs have also been used in combination with MRI for many other in vivo applications, such as imaging of activated microglia during brain inflammation [301],
tracking of stem cells [302–304], image-guided treatment of anemia using bacteria loaded with IONPs [305], or to carry out vascular imaging [306, 307], among
others.
73
Reprinted from the journal