Ultrasmall superparamagnetic iron oxide nanoparticle uptake as noninvasive marker of aortic wall inflammation on MRI: proof of concept study

How to improve epidemiological trustworthiness concerning abdominal aortic aneurysms

BACKGROUND

Research on degenerative abdominal aortic aneurysms (AAA) is hampered by complex pathophysiology, sub-optimal pre-clinical models, and lack of effective medical therapies. In addition, trustworthiness of existing epidemiological data is impaired by elements of ambiguity, inaccuracy, and inconsistency. Our aim is to foster debate concerning the trustworthiness of AAA epidemiological data and to discuss potential solutions.

METHODS

We searched the literature from the last five decades for relevant epidemiological data concerning AAA development, rupture, and repair. We then discussed the main issues burdening existing AAA epidemiological figures and proposed suggestions potentially beneficial to AAA diagnosis, prognostication, and management.

RESULTS

Recent data suggest a heterogeneous scenario concerning AAA epidemiology with rates markedly varying by country and study cohorts. Overall, AAA prevalence seems to be decreasing worldwide while mortality is apparently increasing regardless of recent improvements in aortic-repair techniques. Prevalence and mortality are decreasing in high-income countries, whereas low-income countries show an increase in both. However, several pieces of information are missing or outdated, thus systematic renewal is necessary. Current AAA definition and surgical criteria do not consider inter-individual variability of baseline aortic size, further decreasing their reliability.

CONCLUSIONS

Switching from flat aortic-size thresholds to relative aortic indices would improve epidemiological trustworthiness regarding AAAs. Aortometry standardization focusing on simplicity, univocity, and accuracy is crucial. A patient-tailored approach integrating clinical data, multi-adjusted indices, and imaging parameters is desirable. Several novel imaging modalities boast promising profiles for investigating the aortic wall. New contrast agents, computational analyses, and artificial intelligence-powered software could provide further improvements.

Iron oxide nanoparticles for treatment and diagnosis of chronic inflammatory diseases: A systematic review

Chronic inflammatory conditions are among the most prevalent diseases worldwide. Several debilitating diseases such as atherosclerosis, inflammatory bowel disease, rheumatoid arthritis, and Alzheimer's are linked to chronic inflammation. These conditions often develop into complex and fatal conditions, making early detection and treatment of chronic inflammation crucial. Current diagnostic methods show high variability and do not account for disease heterogeneity and disease-specific proinflammatory markers, often delaying the disease detection until later stages. Furthermore, existing treatment strategies, including high-dose anti-inflammatory and immunosuppressive drugs, have significant side effects and an increased risk of infections. In recent years, superparamagnetic iron oxide nanoparticles (SPIONs) have shown tremendous biomedical potential. SPIONs can function as imaging modalities for magnetic resonance imaging, and as therapeutic agents due to their magnetic hyperthermia capability. Furthermore, the surface functionalization of SPIONs allows the detection of specific disease biomarkers and targeted drug delivery. This systematic review explores the utility of SPIONs against chronic inflammatory disorders, focusing on their dual role as diagnostic and therapeutic agents. We extracted studies indexed in the Web of Science database from the last 10 years (2013-2023), and applied systematic inclusion criteria. This resulted in a final selection of 38 articles, which were analyzed for nanoparticle characteristics, targeted diseases, in vivo and in vitro models used, and the efficacy of the therapeutic or diagnostic modalities. The results revealed that ultrasmall SPIONs are excellent for imaging arterial and neuronal inflammation. Furthermore, novel therapies using SPIONs loaded with chemotherapeutic drugs show promise in the treatment of inflammatory diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Contrast-enhanced MR Angiography without Gadolinium-based Contrast Material: Clinical Applications Using Ferumoxytol

Vascular imaging can be challenging because of the wide variability of contrast dynamics in different vascular territories and potential safety concerns in patients with renal insufficiency or allergies. Off-label diagnostic use of ferumoxytol, a superparamagnetic iron nanoparticle approved for therapy, is a promising alternative to gadolinium-based contrast agents for MR angiography (MRA). Ferumoxytol has exhibited a reassuring safety profile when used within the dose range recommended for diagnostic imaging. Because of its prolonged and stable intravascular residence, ferumoxytol can be used in its steady-state distribution for a wide variety of imaging indications, including some where conventional MRA is unreliable. In this article, authors discuss some of the major vascular applications of ferumoxytol and highlight how it may be used to provide highly diagnostic images and improve the quality, workflow, and reliability of vascular imaging. Keywords: MR Angiography, MRI Contrast Agent, Cardiac, Vascular © RSNA, 2022.

Pediatric cardiothoracic vasculitis: multimodality imaging review

The pediatric vasculitides are a relatively uncommon and heterogeneous group of disorders characterized by vessel inflammation, often with cardiothoracic involvement. Diagnosis and monitoring are often clinically challenging because of the nonspecific symptoms and laboratory markers. Thus, imaging has assumed increasing importance for early detection of disease activity, extent and complications as well as long-term monitoring pre- and post-treatment. Herein, we review the major pediatric vasculitides with frequent chest manifestations, including Takayasu arteritis, Kawasaki disease, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, Behçet disease and potential mimics. We highlight key clinical features and management considerations, emphasizing the central role of imaging.

Advances in Magnetic Nanoparticles Engineering for Biomedical Applications-A Review

Magnetic iron oxide nanoparticles (MNPs) have been developed and applied for a broad range of biomedical applications, such as diagnostic imaging, magnetic fluid hyperthermia, targeted drug delivery, gene therapy and tissue repair. As one key element, reproducible synthesis routes of MNPs are capable of controlling and adjusting structure, size, shape and magnetic properties are mandatory. In this review, we discuss advanced methods for engineering and utilizing MNPs, such as continuous synthesis approaches using microtechnologies and the biosynthesis of magnetosomes, biotechnological synthesized iron oxide nanoparticles from bacteria. We compare the technologies and resulting MNPs with conventional synthetic routes. Prominent biomedical applications of the MNPs such as diagnostic imaging, magnetic fluid hyperthermia, targeted drug delivery and magnetic actuation in micro/nanorobots will be presented.

Iron Oxide Nanoparticles in Regenerative Medicine and Tissue Engineering

In recent years, many promising nanotechnological approaches to biomedical research have been developed in order to increase implementation of regenerative medicine and tissue engineering in clinical practice. In the meantime, the use of nanomaterials for the regeneration of diseased or injured tissues is considered advantageous in most areas of medicine. In particular, for the treatment of cardiovascular, osteochondral and neurological defects, but also for the recovery of functions of other organs such as kidney, liver, pancreas, bladder, urethra and for wound healing, nanomaterials are increasingly being developed that serve as scaffolds, mimic the extracellular matrix and promote adhesion or differentiation of cells. This review focuses on the latest developments in regenerative medicine, in which iron oxide nanoparticles (IONPs) play a crucial role for tissue engineering and cell therapy. IONPs are not only enabling the use of non-invasive observation methods to monitor the therapy, but can also accelerate and enhance regeneration, either thanks to their inherent magnetic properties or by functionalization with bioactive or therapeutic compounds, such as drugs, enzymes and growth factors. In addition, the presence of magnetic fields can direct IONP-labeled cells specifically to the site of action or induce cell differentiation into a specific cell type through mechanotransduction.

Recent advances in nanomaterials for therapy and diagnosis for atherosclerosis

Atherosclerosis is a chronic inflammatory disease driven by lipid accumulation in arteries, leading to narrowing and thrombosis. It affects the heart, brain, and peripheral vessels and is the leading cause of mortality in the United States. Researchers have strived to design nanomaterials of various functions, ranging from non-invasive imaging contrast agents, targeted therapeutic delivery systems to multifunctional nanoagents able to target, diagnose, and treat atherosclerosis. Therefore, this review aims to summarize recent progress (2017-now) in the development of nanomaterials and their applications to improve atherosclerosis diagnosis and therapy during the preclinical and clinical stages of the disease.

Dynamic changes of inflammation and apoptosis in cerebral ischemia‑reperfusion injury in mice investigated by ferumoxytol‑enhanced magnetic resonance imaging

The inflammatory response and apoptosis are key factors in cerebral ischemia-reperfusion injury. The severity of the inflammatory reaction and apoptosis has an important impact on the prognosis of stroke. The ultrasmall superparamagnetic iron oxide particle has provided an effective magnetic resonance molecular imaging method for dynamic observation of the cell infiltration process in vivo. The aims of the present study were to investigate the inflammatory response of cerebral ischemia-reperfusion injury in mice using ferumoxytol-enhanced magnetic resonance imaging, and to observe the dynamic changes of inflammatory response and apoptosis. In the present study a C57BL/6n mouse cerebral ischemia-reperfusion model was established by blocking the right middle cerebral artery with an occluding suture. Subsequently, the mice were injected with ferumoxytol via the tail vein, and magnetic resonance scanning was performed at corresponding time points to observe the signal changes. Furthermore, blood samples were used to measure the level of serum inflammatory factors, and histological staining was performed to assess the number of iron-swallowing microglial cells and apoptotic cells. The present results suggested that there was no significant difference in the serum inflammatory factors tumor necrosis factor-α and interleukin 1β between the middle cerebral artery occlusion (MCAO) and MCAO + ferumoxytol groups injected with ferumoxytol and physiological saline. The lowest signal ratio in the negative enhancement region was decreased 24 h after reperfusion in mice injected with ferumoxytol. The proportion of iron-swallowing microglial cells and TUNEL-positive cells were the highest at 24 h after reperfusion, and decreased gradually at 48 and 72 h after reperfusion. Therefore, the present results indicated that ferumoxytol injection of 18 mg Fe/kg does not affect the inflammatory response in the acute phase of cerebral ischemia and reperfusion. Ferumoxytol-enhanced magnetic resonance imaging can be used as an effective means to monitor the inflammatory response in the acute phase of cerebral ischemia-reperfusion injury. Furthermore, it was found that activation of the inflammatory response and apoptosis in the acute stage of cerebral ischemia-reperfusion injury is consistent.

USPIOs as targeted contrast agents in cardiovascular magnetic resonance imaging

PURPOSE OF REVIEW

We aim to discuss the diagnostic use of ultra-small superparamagnetic iron oxide (USPIOs) including ferumoxytol in targeted cardiovascular magnetic resonance imaging (MRI).

RECENT FINDINGS

Ferumoxytol is the only USPIO clinically available in the U.S. and is a negatively charged USPIO that has potential use for tracking and characterization of macrophage-infiltrated cardiovascular structures. As an iron supplement that is approved for treatment of iron deficiency anemia, the iron core of ferumoxytol is incorporated into the body once it is phagocytosed by macrophages. In organs or tissues with high inflammatory cellular infiltration, such as atherosclerotic plaques and myocardial infarction, localization of iron-laden macrophages can be visualized on delayed MRI. The iron core of ferumoxytol alters the magnetic susceptibility and results in shortening of T2* and T2 relaxation rates. Areas with high concentration appear hypointense (negative contrast) on T2 and T2* MRI. Recently, in vitro findings support the potential specificity of ferumoxytol interactions with macrophage subtypes, which has implications for therapeutic interventions. With increasing concerns about gadolinium retention in the brain and other tissues, the value of ferumoxytol-enhanced MR for targeted clinical imaging is aided by its positive safety profile in patients with impaired renal function.

SUMMARY

This paper discusses pharmacokinetic properties of USPIOs with a focus on ferumoxytol, and summarizes relevant in vitro, animal, and human studies investigating the diagnostic use of USPIOs in targeted contrast-enhanced imaging. We also discuss future directions for USPIOs as targeted imaging agents and associated challenges.

Pictorial review on abdominal applications of ferumoxytol in MR imaging

Though gadolinium-based contrast agents are the most widely used contrast media in MR for clinical use, problems with nephrogenic systemic fibrosis and tissue deposition render their safety debatable, at least in a selected patient population. Ferumoxytol has the potential to be used as an alternate contrast medium for various clinical applications across multiple organs. It has prolonged intravascular signal and delayed intracellular macrophage uptake which are unique properties compared to gadolinium-based agents. This pictorial review aims to review the current and potential clinical applications of ferumoxytol as a contrast agent in abdominal MR imaging.

Biomedical Imaging: Principles, Technologies, Clinical Aspects, Contrast Agents, Limitations and Future Trends in Nanomedicines

This review article presents the state-of-the-art in the major imaging modalities supplying relevant information on patient health by real-time monitoring to establish an accurate diagnosis and potential treatment plan. We draw a comprehensive comparison between all imagers and ultimately end with our focus on two main types of scanners: X-ray CT and MRI scanners. Numerous types of imaging probes for both imaging techniques are described, as well as reviewing their strengths and limitations, thereby showing the current need for the development of new diagnostic contrast agents (CAs). The role of nanoparticles in the design of CAs is then extensively detailed, reviewed and discussed. We show how nanoparticulate agents should be promising alternatives to molecular ones and how they are already paving new routes in the field of nanomedicine.

Iron oxide nanoparticles as multimodal imaging tools

In medicine, obtaining simply a resolute and accurate image of an organ of interest is a real challenge.