Cutaneous changes of nephrogenic systemic fibrosis: predictor of early mortality and association with gadolinium exposure

Renal clearable magnetic nanoparticles for magnetic resonance imaging and guided therapy

Magnetic resonance imaging (MRI) is a non-invasive, radiation-free imaging technique widely used for disease detection and therapeutic evaluation due to its infinite penetration depth. Magnetic nanoparticles (MNPs) have unique magnetic and physicochemical properties, making them ideal as contrast agents for MRI. However, the in vivo toxicity of MNPs, resulting from metal ion leakage and long-term accumulation in the reticuloendothelial system (RES), limits their clinical application. To overcome these challenges, there is considerable interest in the development of renal-clearable MNPs that can be completely cleared through the kidney, reducing retention time and potential toxic risks. In this review, we provide an overview of recent advancements in the development of renal-clearable MNPs for disease imaging and treatment. We discuss the factors influencing renal clearance, summarize the types of renal-clearable MNPs, their synthesis methods, and biomedical applications. This review aims to offer comprehensive information for the design and clinical translation of renal-clearable MNPs. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Biosensing.

Optically active organic and inorganic nanomaterials for biological imaging applications: A review

Recent advancements in the field of nanotechnology have enabled targeted delivery of drug agents in vivo with minimal side effects. The use of nanoparticles for bio-imaging has revolutionized the field of nanomedicine by enabling non-invasive targeting and selective delivery of active drug moieties in vivo. Various inorganic nanomaterials like mesoporous silica nanoparticles, gold nanoparticles, magnetite nanoparticles graphene-based nanomaterials etc., have been created for multimodal therapies with varied multi-imaging modalities. These nanomaterials enable us to overcome the disadvantages of conventional imaging contrast agents (organic dyes) such as lack of stability in vitro and in vivo, high reactivity, low-quantum yield and poor photo stability. Inorganic nanomaterials can be easily fabricated, functionalised and modified as per requirements. Recently, advancements in synthesis techniques, such as the ability to generate molecules and construct supramolecular structures for specific functionalities, have boosted the usage of engineered nanomaterials. Their intrinsic physicochemical properties are unique and they possess excellent biocompatibility. Inorganic nanomaterial research has developed as the most actively booming research fields in biotechnology and biomedicine. Inorganic nanomaterials like gold nanoparticles, magnetic nanoparticles, mesoporous silica nanoparticles, graphene-based nanomaterials and quantum dots have shown excellent use in bioimaging, targeted drug delivery and cancer therapies. Biocompatibility of nanomaterials is an important aspect for the evolution of nanomaterials in the bench to bedside transition. The conduction of thorough and meticulous study for safety and efficacy in well-designed clinical trials is absolutely necessary to determine the functional and structural relationship between the engineered nanomaterial and its toxicity. In this article an attempt is made to throw some light on the current scenario and developments made in the field of nanomaterials in bioimaging.

The Clinical Manifestations and Efficacy of Different Treatments Used for Nephrogenic Systemic Fibrosis: A Systematic Review

Aim

Nephrogenic systemic fibrosis (NSF) is a rare disorder that occurs in association majorly with chronic kidney disease (CKD). The lack of collective quantitative data on its clinical manifestations and the different treatment options' efficacy, call the need for our investigation.

Methods

A systematic review was conducted covering a timeline from inception up to July 2022 without any restrictions. Article screening and data extraction were performed independently on PubMed, Google Scholar, ScienceDirect, and Cochrane Library. The keywords that we used were CKD, NSF, Gadolinium enduced fibrosis, etc; shortlisted articles were assessed for risk of bias. Data were presented as frequencies and percentages, with a confidence interval of 95%. A chi-square test was also done to find significant relationships, with a p-value <0.05 considered significant.

Results

We had 83 patients in this review consisting of 44 (55.7%) females with a mean age of 51.4±14.6 years. Sixty-nine (83.1%) patients had chronic kidney disease predisposition to NSF. Previous exposure to gadolinium-based contrast dyes was seen in 66 (79.5%) patients). The most common symptom in patients was cutaneous lesions in 69 (83.1%) patients. The most used treatments were ultraviolet therapy, renal transplant, and extracorporeal photopheresis; in 13.3% of the patients each. Condition in most patients either improved (67.1%) or remained stable (11.8%). Chi-square testing found that the treatments offered were also seen to be significantly related to outcome (p=0.015).

Conclusion

The findings in this study provide a quantitative measurement of NSF's presentations and treatment efficacies. This serves to make way for researchers to form comprehensive guidelines on the presentation-based treatment of NSF.

Drugs associated with systemic sclerosis: An updated list of suspected drugs using the WHO pharmacovigilance database

OBJECTIVE

The pathophysiological mechanisms involved in systemic sclerosis (SSc), especially the triggering factor, are poorly understood. The literature supporting the role of drugs in the onset of SSc primarily relies on case reports, short series or previous studies of old drugs. We aimed to update the list of suspected drugs associated with SSc (DASSc).

METHODS

Analyzing the World Health Organization (WHO) pharmacovigilance database (Vigibase®), we collected all individual case safety reports (ICSRs) of drugs putatively associated with SSc reported since 1967 using the Medical Dictionary for Regulatory Activities preferred terms "systemic sclerosis" and "scleroderma". For each drug, a disproportionality analysis was performed by calculating the information component (IC). An identified drug was considered significant if the IC₀₂₅ was >0.

RESULTS

A total of 2800 deduplicated ICSRs of DASSc were identified, accounting for 509 ICSRs and 38 suspected DASSc after exclusion of protopathic and indication biases. Anticancer drugs were the most represented drug class, accounting for 16/38 (42%) of DASSc and 317/509 (62.3%) of ICSRs, which occurred mostly in the first years after the introduction of the drugs. Among these, taxane-based agents, bleomycin, vinblastine, imatinib, dacarbazine, pembrolizumab and pemetrexed were associated with the highest disproportionate reporting. Hormone replacement therapy, romiplostim and eculizumab were associated with a significant signal. DASSc was considered a serious adverse drug reaction in 404 (92%, n = 441) cases with 41 (9%) cases resulting in death.

CONCLUSION

Several new drugs with significant disproportionality signals were identified as potential drugs implicated the development of SSc, particularly anticancer drugs.

Iron(III) Coordinated Theranostic Polyprodrug with Sequential Receptor-Mitochondria Dual Targeting and T1-Weighted Magnetic Resonance Imaging Potency for Effective and Precise Chemotherapy

The sequential cancer cell receptor and mitochondria dual-targeting single delivery agent deliver chemotherapeutic drug effectively and precisely at the targeted site has become a promising strategy to enhance the drug efficacy and suppressions of cancer cell drug resistance prominence. Herein, required specialty molecules like a chemotherapeutic drug [camptothecin (CPT)], mitochondriotropic segment (triphenyl phosphonium cation) receptor targeting ligand (biotin), and magnetic resonance imaging (MRI)-contrast agent (iron-complex) were tethered to the polyprodrug, CP TP PG BN Fe, using the ring-opening metathesis polymerization technique for potential chemotherapy and simultaneous MRI-based diagnosis. This amphiphilic polyprodrug spontaneously aggregated into nanospheres and exhibited remarkable T₁-weighted MRI proficiency. Detail in vitro cellular studies revealed unambiguous mitochondrial delivery of CPT, which eventually enhanced the chemotherapeutic efficacy of CP TP PG BN Fe. Therefore, MRI-tracking, receptor-mitochondria dual targeting, theranostic polyprodrug, and CP TP PG BN Fe opened the way for effective and precise chemotherapy, which would have the attractive potential for diagnosis and decisive dose determination in clinical implications.

Unique Random-Block Polymer Architecture for Site-Specific Mitochondrial Sequestration-Aided Effective Chemotherapeutic Delivery and Enhanced Fluorocarbon Segmental Mobility-Facilitated 19F Magnetic Resonance Imaging

The elevation of the chemotherapeutic efficacy and attenuation of its side effects on healthy cells and tissues become one of the prime targets for the treatment of cancer. Toward this direction, a sequential receptor and mitochondria dual-targeting strategy was implemented in the DX TP PG BN ¹⁹F theranostic polymer that was anchored with the chemotherapeutic agent doxorubicin, receptor-targeting biotin, and mitochondria-targeting triphenylphosphonium cations. The polymer was flourished with a unique ¹⁹F magnetic resonance imaging (MRI) tracer that exhibited high segmental mobility and eventually led to prolonged T₂ relaxation time. Furthermore, for the sake of amphiphilicity, the DX TP PG BN ¹⁹F polymer spontaneously aggregated into nano-sphere with positive zeta potential, where the MRI tracer and biotin embedded at the exterior and displayed site-specific targeting and remarkable ¹⁹F MRI capability simultaneously. The mitochondria-targeting competency of the DX TP PG BN ¹⁹F theranostic polymer was investigated by comparing the non-mitochondrial-targeting DX PG BN ¹⁹F polymer using fluorescence microscopic cell imaging in human cervical, HeLa, and breast MCF-7 carcinoma cell lines. Moreover, cytotoxicity experiments of the aforementioned theranostic polymers clarified the enhancement of the chemotherapeutic efficacy of DX TP PG BN ¹⁹F theranostic polymers through effective and precise mitochondrial doxorubicin delivery that forced to follow the apoptotic path.

Drug-induced scleroderma-like lesion

Drug-induced scleroderma-like lesion is a condition in which administration of a drug induces skin sclerotic lesions similar to systemic sclerosis or morphea. The clinical manifestations of drug-induced scleroderma-like lesion can be divided into two types: scleroderma-like lesions and morphea-like plaques. A wide variety of drugs can cause drug-induced scleroderma-like lesion. Bleomycin, _L-tryptophan, vinyl chloride, and phytonadione (vitamin K₁) have been reported, but in recent years, cases due to chemotherapeutic agents, such as taxane-based agents, gemcitabine, and tegafur-uracil, and immune checkpoint inhibitors have increased. Drug-induced scleroderma-like lesion differs from systemic sclerosis in that it does not include Raynaud's phenomenon, nail-fold capillary abnormality, organ involvement, such as reflux esophagitis, interstitial pneumonia, renal crisis, or anti-nuclear Abs. On the other hand, there are reports of cases in which Raynaud's phenomenon, positive conversion of anti-nuclear Abs, and development of skin sclerosis from the fingers developed after initiation of the drug. Whether the skin sclerosis improves after discontinuation of the drug depends on the patient. In patients with severe skin sclerosis, functional impairment, such as flexion contracture of the fingers, may occur, and systemic therapy, such as steroids, may be necessary. When treating patients with skin sclerosis, it is important to keep in mind the possibility that the sclerotic lesion may be induced by a drug.

VHPKQHR Peptide Modified Ultrasmall Paramagnetic Iron Oxide Nanoparticles Targeting Rheumatoid Arthritis for T1-Weighted Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) could be the ideal diagnostic modality for early rheumatoid arthritis (RA). Vascular cell adhesion molecule-1 (VCAM-1) is highly expressed in synovial locations in patients with RA, which could be a potential target protein for RA diagnosis. The peptide VHPKQHR (VHP) has a high affinity to VCAM-1. To make the contrast agent to target RA at an early stage, we used VHP and ultrasmall paramagnetic iron oxide (USPIO) to synthesize UVHP (U stands for USPIO) through a chemical reaction with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. The size of UVHP was 6.7 nm; the potential was −27.7 mV, and the r₂/r₁ value was 1.73. Cytotoxicity assay exhibited that the cell survival rate was higher than 80% at even high concentrations of UVHP (Fe concentration 200 µg/mL), which showed the UVHP has low toxicity. Compared with no TNF-α stimulation, VCAM-1 expression was increased nearly 3-fold when mouse aortic endothelial cells (MAECs) were stimulated with 50 ng/mL TNF-α; cellular Fe uptake was increased very significantly with increasing UVHP concentration under TNF-α treatment; cellular Fe content was 17 times higher under UVHP with Fe concentration 200 µg/mL treating MAECs. These results indicate that UVHP can target overexpression of VCAM-1 at the cellular level. RA mice models were constructed with adjuvant-induced arthritis. In vivo MRI and biodistribution results show that the signal intensity of knee joints was increased significantly and Fe accumulation in RA model mice compared with normal wild-type mice after injecting UVHP 24 h. These results suggest that we have synthesized a simple, low-cost, and less toxic contrast agent UVHP, which targeted VCAM-1 for early-stage RA diagnosis and generates high contrast in T₁-weighted MRI.

New-onset seizures in adults: Low diagnostic yield of gadolinium contrast in initial brain MRI evaluation

BACKGROUND AND PURPOSE

The diagnostic utility of contrast MR-imaging in adult new-onset seizures without clinically suspected neoplasia or infection is not well defined in the literature. Imaging guidelines consider both contrast and noncontrast MR-imaging examinations appropriate in this clinical scenario. The purpose of this study was to evaluate the utility of contrast MR-sequences in evaluation of seizure in patients without suspicion for neoplasia or infection.

METHODS

Imaging and clinical data were reviewed for 103 consecutive patients admitted for phase-1 seizure monitoring with the following criteria: (1) MRI-brain performed with/without intravenous contrast; (2) no clinical suspicion for central nervous system (CNS) infection; and (3) no history of CNS neoplasia, or suspected metastatic disease. Readers designated cases as lesional or nonlesional. Lesional cases were further categorized as either visualized on noncontrast sequences only, contrast sequences only, or both.

RESULTS

29/103 (28%) patients had epileptogenic lesions, 74/103 (72%) were nonlesional studies. 29/29 (100%) lesional abnormalities were detected on noncontrast sequences (sensitivity 100% [95 confidence interval (CI): 88-100], specificity 100% [95 CI: 95-100]). 23/29 (79.3%) lesional cases were visualized on both noncontrast and postcontrast sequences. 6/29 (20.7%) were visualized only on noncontrast sequences. No lesional cases were detected exclusively on postcontrast MR sequences. With an observed nonlesional extraneous contrast MR-imaging rate of 72%, estimated excess cost of contrast MR-imaging per 1000 patients using Medicare data was $103,680 USD.

CONCLUSIONS

Contrast MR-imaging has limited diagnostic utility in initial screening of adult new-onset seizure patients without clinically suspected neoplasia or infection. More judicious use of contrast MR-imaging in this patient population may reduce unnecessary exposure to gadolinium and lower associated healthcare costs.

Nephrogenic Systemic Fibrosis as a Complication after Gadolinium-Containing Contrast Agents: A Rapid Review

Introduction: Nephrogenic systemic fibrosis (NFS) is a generalized disorder occurring in people with kidney failure. This new disease entity can lead to significant disability or even death. Gadolinium-associated systemic fibrosis is related to exposure to contrast agents used for magnetic resonance imaging. The aim of this study was to review the literature in available scientific databases on NFS—complication after gadolinium-containing contrast agents. Methods: PubMed and Cochrane Library databases were searched using adequate key words. A literature review of the described cases of NSF occurrence after exposure to gadolinium-containing contrast agents was performed. A review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A review written protocol was not drafted. Results: Originally, 647 studies were searched in scientific databases. After rejecting the duplicate results, 515 results were obtained. Finally, nine studies were included in the review. A total of 173 cases with NSF were included in the analysis. The majority of patients were undergoing dialysis. The contrast agent used for MRI was most often gadodiamide and gadopentetate dimeglumine. The time from exposure to NSF symptoms was from two days to three years. Three authors pointed out other factors in their papers that could potentially influence the occurrence of NSF. These included: metabolic acidosis, ongoing infection, higher doses of erythropoietin and higher serum concentrations of ionized calcium and phosphate. Since 2008, the number of reported cases of NSF has decreased significantly. More recent guidelines and reports indicate that not all contrast agents are associated with the same risk of developing NSF. Conclusions: Most NSF occurs after exposure to linear contrast agents. Therefore, it is recommended to limit their use, especially in dialyzed patients and patients with a GFR < 30 mL/min.

High-resolution T1 MRI via renally clearable dextran nanoparticles with an iron oxide shell

Contrast agents for magnetic resonance imaging (MRI) improve anatomical visualizations. However, owing to poor image resolution in whole-body MRI, resolving fine structures is challenging. Here, we report that a nanoparticle with a polysaccharide supramolecular core and a shell of amorphous-like hydrous ferric oxide generating strong T₁ MRI contrast (with a relaxivity coefficient ratio of ~1.2) facilitates the imaging, at resolutions of the order of a few hundred micrometres, of cerebral, coronary and peripheral microvessels in rodents and of lower-extremity vessels in rabbits. The nanoparticle can be synthesized at room temperature in aqueous solution and in the absence of surfactants, has blood circulation and renal clearance profiles that prevent opsonization, and leads to better imaging performance than Dotarem (gadoterate meglumine), a clinically approved gadolinium-based MRI contrast agent. The nanoparticle's biocompatibility and imaging performance may prove advantageous in a broad range of preclinical and clinical applications of MRI.

Comprehensive phenotyping revealed transient startle response reduction and histopathological gadolinium localization to perineuronal nets after gadodiamide administration in rats

Gadolinium based contrast agents (GBCAs) are widely used in clinical MRI since the mid-1980s. Recently, concerns have been raised that trace amounts of Gadolinium (Gd), detected in brains even long time after GBCA application, may cause yet unrecognized clinical consequences. We therefore assessed the behavioral phenotype, neuro-histopathology, and Gd localization after repeated administration of linear (gadodiamide) or macrocyclic (gadobutrol) GBCA in rats. While most behavioral tests revealed no difference between treatment groups, we observed a transient and reversible decrease of the startle reflex after gadodiamide application. Residual Gd in the lateral cerebellar nucleus was neither associated with a general gene expression pathway deregulation nor with neuronal cell loss, but in gadodiamide-treated rats Gd was associated with the perineuronal net protein aggrecan and segregated to high molecular weight fractions. Our behavioral finding together with Gd distribution and speciation support a substance class difference for Gd presence in the brain after GBCA application.

A Systematic Review of 639 Patients with Biopsy-confirmed Nephrogenic Systemic Fibrosis

Background Although nephrogenic systemic fibrosis (NSF) affects the use of gadolinium-based contrast agents (GBCAs) in MRI, there continues to be limited knowledge because of the small number of patients with NSF. Purpose To perform a systematic review of NSF. Materials and Methods PubMed database was searched by using the term "Nephrogenic systemic fibrosis" from January 2000 to February 2019. Articles reporting details on individual patients with NSF diagnosis on the basis of both clinical presentations and biopsy confirmation were included. Data were pooled and authors were contacted for clarifications. Rates of NSF were compared through 2008 versus after 2008 and for group I versus group II GBCAs, assuming equal market share. Results Included were 639 patients from 173 articles. Data regarding sex were found for 295 men and 254 women. Age at NSF symptom onset was reported for 177 patients (mean, 49 years ± 16 [standard deviation]; age range, 6-87 years). There were 529 patients with documented exposure to GBCAs including gadodiamide (n = 307), gadopentetate dimeglumine (n = 49), gadoversetamide (n = 6), gadobutrol (n = 1), gadobenate dimeglumine (n = 1), multiple (n = 41), and unknown (n = 120). Among patients with previous exposure, only seven patients were administered GBCA after 2008, yielding a lower rate of NSF after 2008 (P < .001). There were motion limitations in 70.8% (296 of 418) of patients, indicating a more serious debilitation. Associated factors reported for NSF included exposure to GBCA group I (P < .001), dialysis, proinflammatory conditions, hyperphosphatemia, β-blockers, and epoetin. For 341 patients with follow-up, 12 patients were cured and 72 patients partially improved including one during pregnancy. Among those 84 patients reported as cured or improved, in 34 patients cure or improvement occurred after renal function restoration. Four deaths were attributed to NSF. Conclusion Although 639 patients with biopsy-confirmed nephrogenic systemic fibrosis were reported, only seven were after gadolinium-based contrast agent exposure after 2008, indicating that regulatory actions and practice changes have been effective preventive measures. Improvement and sometimes cure with renal function restoration are now possible. © RSNA, 2019 See also the editorial by Davenport in this issue.

A pH-Sensitive Zwitterionic Iron Complex Probe with High Biocompatibility for Tumor-Specific Magnetic Resonance Imaging

Accurate diagnosis of tumor characteristics, including its location and boundary, is of immense value to subsequent therapy. Activatable magnetic resonance imaging (MRI) contrast agents that respond to tumor-specific microenvironments, such as the redox state, pH, and enzyme activity, enable better mapping of tumor tissue. However, the practical application of most reported activatable agents is hampered by problems including potential toxicity, inefficient elimination, and slow activation. In this study, we developed a zwitterionic iron complex (Fe-ZDS) as a positive MRI contrast agent for tumor-specific imaging. Fe-ZDS could dissociate in weakly acidic solution rapidly, accompanied by clear longitudinal relaxivity (r₁ ) enhancement, which enabled the complex to act as a pH-sensitive contrast agent for tumor-specific MR imaging. In vivo experiments showed that Fe-ZDS rapidly enhanced the tumor-to-normal contrast ratio by >40 %, which assisted in distinguishing the tumor boundary. Furthermore, Fe-ZDS circulated freely in the bloodstream and was excreted relatively safely via kidneys owing to its zwitterionic nature. Therefore, Fe-ZDS is an ideal candidate for a tumor-specific MRI contrast agent and holds considerable potential for clinical translation.

[Non-iodinated contrast media nephrotoxicity]

The development of interventional radiology techniques regularly exposes patients to the potential renal toxocity of iodinated contrast media. Faced with this risk of nephrotoxicity, gadolinium-based contrast agents have long been considered as a safe alternative to iodinated contrast media, especially in sensitive or at risk patients. However, these gadolinium-based contrast agents are not devoid of nephrotoxicity and present another risk, a complication related to renal failure, the nephrogenic systemic fibrosis. European and US recommendations from health agencies have recently come closer, defining groups of patients at risk of nephrogenic systemic fibrosis according to their level of renal function and the type of gadolinium-based contrast agent used. What are the real renal risks for these products? How to evaluate the benefit-risk balance of the patient to choose a radiological examination in an informative, effective and safe way? This article focuses on the description of the risks of gadolinium-based contrast agents, reviews existing recommendations and best practices to guide the choice of clinicians.

Gadolinium deposition and the potential for toxicological sequelae - A literature review of issues surrounding gadolinium-based contrast agents

Every year, approximately 30 million magnetic resonance imaging scans are enhanced with gadolinium-based contrast agents (GBCAs) worldwide. Although the development of nephrogenic systemic fibrosis in patients with renal impairment is well-documented, over recent years it has become apparent that exposure to GBCAs can potentially result in gadolinium deposition within human bone and brain tissue even in the presence of normal renal function. This review will address some of the controversies surrounding the safety of GBCA administration based on evidence from in vivo experiments, animal studies and clinical studies. We additionally evaluate the potential risk of toxicity from exposure to gadolinium in light of new guidance published by the US Food and Drug Administration and the European Medicines Agency, and discuss whether gadolinium deposition disease exists as a new diagnosis.

Do we need gadolinium-based contrast medium for brain magnetic resonance imaging in children?

BACKGROUND

Brain imaging is the most common examination in pediatric magnetic resonance imaging (MRI), often combined with the use of a gadolinium-based contrast medium. The application of gadolinium-based contrast medium poses some risk. There is limited evidence of the benefits of contrast medium in pediatric brain imaging.

OBJECTIVE

To assess the diagnostic gain of contrast-enhanced sequences in brain MRI when the unenhanced sequences are normal.

MATERIALS AND METHODS

We retrospectively assessed 6,683 brain MR examinations using contrast medium in children younger than 16 years in the pediatric radiology department of the University Hospital Leipzig to determine whether contrast-enhanced sequences delivered additional, clinically relevant information to pre-contrast sequences. All examinations were executed using a 1.5-T or a 3-T system.

RESULTS

In 8 of 3,003 (95% confidence interval 0.12-0.52%) unenhanced normal brain examinations, a relevant additional finding was detected when contrast medium was administered. Contrast enhancement led to a change in diagnosis in only one of these cases.

CONCLUSION

Children with a normal pre-contrast brain MRI rarely benefit from contrast medium application. Comparing these results to the risks and disadvantages of a routine gadolinium application, there is substantiated numerical evidence for avoiding routine administration of gadolinium in a pre-contrast normal MRI examination.

Gadolinium accumulation after contrast-enhanced magnetic resonance imaging: Which implications in patients with Crohn's disease?

Crohn's disease (CD) is a chronic inflammatory condition of the bowel, characterized by an alternation of remission and relapse phases, leading to a progressive intestinal damage with loss of function. Magnetic resonance enterography has been widely used in the past for the evaluation of fistulizing disease, but its use increased over time, being considered helpful in different moments of disease course. Intravenous injection of Gadolinium-based contrast agents has been demonstrated to be crucial to assess mucosal inflammation, transmural involvement, and extraintestinal disease. Recently, Gadolinium accumulation in human tissues has been increasingly reported, although clinical implications of this event are still unclear. In the present paper, we review the main evidence on the topic, focusing on the potential implications for gastroenterological practice.

Adverse Effects of Gadolinium-Based Contrast Agents: Changes in Practice Patterns

Gadolinium-based contrast agents have been used for magnetic resonance imaging (MRI) examinations since the late 1980s with an excellent overall cumulative safety record. Initially favored for use in patients with renal impairment because of lack of significant nephrotoxic effect at clinical doses, in 2006, multiple reports convincingly linked the rare but serious disease nephrogenic systemic fibrosis to the administration of gadolinium-based contrast agents in patients with severe renal failure. This in turn led to new policies on administration of these agents, resulting in changes in practice patterns that have virtually resulted in the elimination of the disease after the year 2009. The purpose of this review is to summarize the factors that led to the emergence of nephrogenic systemic fibrosis, including the risk associated with different types of contrast agents based on their stability, and the changes in practice patterns and usage of gadolinium-based contrast agents in recent years that have been mainly driven by the discovery and association with nephrogenic systemic fibrosis. The article will conclude with a brief overview of new emerging safety concerns that could further impact the use of this class of contrast agents and impact practice patterns in the future.

Exceedingly small iron oxide nanoparticles as positive MRI contrast agents

Medical imaging is routine in the diagnosis and staging of a wide range of medical conditions. In particular, magnetic resonance imaging (MRI) is critical for visualizing soft tissue and organs, with over 60 million MRI procedures performed each year worldwide. About one-third of these procedures are contrast-enhanced MRI, and gadolinium-based contrast agents (GBCAs) are the mainstream MRI contrast agents used in the clinic. GBCAs have shown efficacy and are safe to use with most patients; however, some GBCAs have a small risk of adverse effects, including nephrogenic systemic fibrosis (NSF), the untreatable condition recently linked to gadolinium (Gd) exposure during MRI with contrast. In addition, Gd deposition in the human brain has been reported following contrast, and this is now under investigation by the US Food and Drug Administration (FDA). To address a perceived need for a Gd-free contrast agent with pharmacokinetic and imaging properties comparable to GBCAs, we have designed and developed zwitterion-coated exceedingly small superparamagnetic iron oxide nanoparticles (ZES-SPIONs) consisting of ∼3-nm inorganic cores and ∼1-nm ultrathin hydrophilic shell. These ZES-SPIONs are free of Gd and show a high T₁ contrast power. We demonstrate the potential of ZES-SPIONs in preclinical MRI and magnetic resonance angiography.

Gadolinium-based contrast agents: A comprehensive risk assessment

Gadolinium-based contrast agents (GBCAs) have been used in magnetic resonance imaging (MRI) since the 1980s and are now administered in up to 35% of all MRI examinations. While GBCAs were initially felt to carry minimal risk, the subsequent identification of GBCAs as the key etiologic factor in the development of nephrogenic systemic fibrosis (NSF) has raised concerns about the broader health impacts of gadolinium exposure. Clinicians, radiologists, and patients should be aware of the most up-to-date data pertaining to the risks of GBCA administration. Specific issues covered in this review article include immediate adverse reactions; pregnancy and lactation; and gadolinium deposition and toxicity, with a special focus on NSF. Practice recommendations based on the presented data, as well as current professional society guidelines, are provided for each section.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 5 J. MAGN. RESON. IMAGING 2017;46:338-353.

Management of Critical Limb Ischemia

Critical limb ischemia (CLI) is a clinical syndrome of ischemic pain at rest or tissue loss, such as nonhealing ulcers or gangrene, related to peripheral artery disease. CLI has a high short-term risk of limb loss and cardiovascular events. Noninvasive or invasive angiography help determine the feasibility and approach to arterial revascularization. An endovascular-first approach is often advocated based on a lower procedural risk; however, specific patterns of disease may be best treated by open surgical revascularization. Balloon angioplasty and stenting form the backbone of endovascular techniques, with drug-eluting stents and drug-coated balloons offering low rates of repeat revascularization. Combined antegrade and retrograde approaches can increase success in long total occlusions. Below the knee, angiosome-directed angioplasty may lead to greater wound healing, but failing this, any straight-line flow into the foot is pursued. Hybrid surgical techniques such as iliac stenting and common femoral endarterectomy are commonly used to reduce operative risk. Lower extremity bypass grafting is most successful with a good quality, long, single-segment autogenous vein of at least 3.5-mm diameter. Minor amputations are often required for tissue loss as a part of the treatment strategy. Major amputations (at or above the ankle) limit functional independence, and their prevention is a key goal of CLI therapy. Medical therapy after revascularization targets risk factors for atherosclerosis and assesses wound healing and new or recurrent flow-limiting disease. The ongoing National Institutes of Health-sponsored Best Endovascular Versus Best Surgical Therapy in Patients With Critical Limb Ischemia (BEST-CLI) study is a randomized trial of the contemporary endovascular versus open surgical techniques in patients with CLI.

Gadolinium-Induced Fibrosis

Gadolinium-based contrast agents (GBCAs), once believed to be safe for patients with renal disease, have been strongly associated with nephrogenic systemic fibrosis (NSF), a severe systemic fibrosing disorder that predominantly afflicts individuals with advanced renal dysfunction. We provide a historical perspective on the appearance and disappearance of NSF, including its initial recognition as a discrete clinical entity, its association with GBCA exposure, and the data supporting a causative relationship between GBCA exposure and NSF. On the basis of this body of evidence, we propose that the name gadolinium-induced fibrosis (GIF) more accurately reflects the totality of knowledge regarding this disease. Use of high-risk GBCAs, such as formulated gadodiamide, should be avoided in patients with renal disease. Restriction of GBCA use in this population has almost completely eradicated new cases of this debilitating condition. Emerging antifibrotic therapies may be useful for patients who suffer from GIF.

Imaging patients with renal impairment

Imaging with intravascular contrast media is generally considered safe, particularly in patients without renal failure. However, as renal function deteriorates, the potential risk of nonallergic-type adverse events increases. This presents a unique challenge, particularly when the use of intravenous contrast media is deemed essential for diagnostic purposes. Following a discussion regarding the definition and epidemiology of kidney injury, this review focuses on the evolving understanding of both contrast-induced nephropathy and nephrogenic systemic fibrosis and discusses preventative strategies aimed at minimizing the risk of developing these entities. Alternative non-contrast imaging techniques are also discussed.

Pathophysiology of gadolinium-associated systemic fibrosis

Systemic fibrosis from gadolinium-based magnetic resonance imaging contrast is a scourge for the afflicted. Although gadolinium-associated systemic fibrosis is a rare condition, the threat of litigation has vastly altered clinical practice. Most theories concerning the etiology of the fibrosis are grounded in case reports rather than experiment. This has led to the widely accepted conjecture that the relative affinity of certain contrast agents for the gadolinium ion inversely correlates with the risk of succumbing to the disease. How gadolinium-containing contrast agents trigger widespread and site-specific systemic fibrosis and how chronicity is maintained are largely unknown. This review highlights experimentally-derived information from our laboratory and others that pertain to our understanding of the pathophysiology of gadolinium-associated systemic fibrosis.

Ferumoxytol-Enhanced Magnetic Resonance Imaging in Late-Stage CKD

Ferumoxytol is a superparamagnetic iron oxide particle encapsulated by a semisynthetic carbohydrate with properties that can be used by the nephrologist for diagnosis and therapy. Ferumoxytol is approved by the US Food and Drug Administration for treating iron deficiency anemia in the setting of chronic kidney disease, but not for clinical diagnostic imaging. It has gained appeal as a magnetic resonance imaging contrast agent in patients with estimated glomerular filtration rates < 30mL/min/1.73m(2) in whom gadolinium-based contrast magnetic resonance imaging agents are relatively contraindicated because of the association with gadolinium deposition and nephrogenic systemic fibrosis. Ferumoxytol metabolism is not dependent on kidney function, but rather is removed from the circulation by the reticuloendothelial system of the liver, spleen, and bone marrow. Additionally, the prolonged intravascular half-life (>14 hours) of ferumoxytol allows for longer image acquisition and repeat imaging, if necessary. In patients with contraindications for gadolinium contrast agents, ferumoxytol is an alternative agent for vascular assessment, including patency and course.

Advantages and Limitations of Focal Liver Lesion Assessment with Ultrasound Contrast Agents: Comments on the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines

Contrast-enhanced ultrasound (CEUS) represents a significant breakthrough in sonography. Due to US contrast agents (UCAs) and contrast-specific techniques, sonography offers the potential to show enhancement of liver lesions in a similar way as contrast-enhanced cross-sectional imaging techniques. The real-time assessment of liver perfusion throughout the vascular phases, without any risk of nephrotoxicity, represents one of the major advantages that this technique offers. CEUS has led to a dramatic improvement in the diagnostic accuracy of US and subsequently has been included in current guidelines as an important step in the diagnostic workup of focal liver lesions (FLLs), resulting in a better patient management and cost-effective therapy. The purpose of this review was to provide a detailed description of contrast agents used in different cross-sectional imaging procedures for the study of FLLs, focusing on characteristics, indications and advantages of UCAs in clinical practice.

EDTA capped iron oxide nanoparticles magnetic micelles: drug delivery vehicle for treatment of chronic myeloid leukemia and T1–T2 dual contrast agent for magnetic resonance imaging

This study shows that multiple functionalities like drug delivery and T₁–T₂ dual modalities can be achieved by a proper surface architecture.

Evidence Suggesting a Role of Iron in a Mouse Model of Nephrogenic Systemic Fibrosis

Nephrogenic systemic fibrosis is associated with gadolinium contrast exposure in patients with reduced kidney function and carries high morbidity and mortality. We have previously demonstrated that gadolinium contrast agents induce in vivo systemic iron mobilization and in vitro differentiation of peripheral blood mononuclear cells into ferroportin (iron exporter)-expressing fibrocytic cells. In the present study we examined the role of iron in a mouse model of nephrogenic systemic fibrosis. Chronic kidney disease was induced in 8-week-old male Balb/C mice with a two-step 5/6 nephrectomy surgery. Five groups of mice were studied: control (n = 5), sham surgery control (n = 5), chronic kidney disease control (n = 4), chronic kidney disease injected with 0.5 mmol/kg body weight of Omniscan 3 days per week, for a total of 10 injections (n = 8), and chronic kidney disease with Omniscan plus deferiprone, 125 mg/kg, in drinking water (n = 9). Deferiprone was continued for 16 weeks until the end of the experiment. Mice with chronic kidney disease injected with Omniscan developed skin changes characteristic of nephrogenic systemic fibrosis including hair loss, reddening, ulceration, and skin tightening by 10 to 16 weeks. Histopathological sections demonstrated dermal fibrosis with increased skin thickness (0.25±0.06 mm, sham; 0.34±+0.3 mm, Omniscan-injected). Additionally, we observed an increase in tissue infiltration of ferroportin-expressing, fibrocyte-like cells accompanied by tissue iron accumulation in the skin of the Omniscan-treated mice. The deferiprone-treated group had significantly decreased skin thickness (p<0.05) and significantly decreased dermal fibrosis compared to the Omniscan-only group. In addition, iron chelation prevented tissue infiltration of ferroportin-expressing, fibrocyte-like cells. Our in vitro experiments demonstrated that exposure to Omniscan resulted in the release of catalytic iron and this was prevented by the iron chelator deferiprone. Deferiprone inhibited the differentiation of human peripheral blood mononuclear cells into ferroportin-expressing cells by immunohistochemical staining and western blot analysis. Our studies support an important role of iron in the pathophysiology of gadolinium chelate toxicity and nephrogenic systemic fibrosis.

Endovascular intervention for peripheral artery disease

Advances in endovascular therapies during the past decade have broadened the options for treating peripheral vascular disease percutaneously. Endovascular treatment offers a lower risk alternative to open surgery in many patients with multiple comorbidities. Noninvasive physiological tests and arterial imaging precede an endovascular intervention and help localize the disease and plan the procedure. The timing and need for revascularization are broadly related to the 3 main clinical presentations of claudication, critical limb ischemia, and acute limb ischemia. Many patients with claudication can be treated by exercise and medical therapy. Endovascular procedures are considered when these fail to improve quality of life and function. In contrast, critical limb ischemia and acute limb ischemia threaten the limb and require more urgent revascularization. In general, endovascular treatments have greater long-term durability for aortoiliac disease than femoral popliteal disease. Infrapopliteal revascularization is generally reserved for critical and acute limb ischemia. Balloon angioplasty and stenting are the mainstays of endovascular therapy. New well-tested innovations include drug-eluting stents and drug-coated balloons. Adjunctive devices for crossing chronic total occlusions or debulking plaque with atherectomy are less rigorously studied and have niche roles. Patients receiving endovascular procedures need a structured surveillance plan for follow-up care. This includes intensive treatment of cardiovascular risk factors to prevent myocardial infarction and stroke, which are the main causes of death. Limb surveillance aims to identify restenosis and new disease beyond the intervened segments, both of which may jeopardize patency and lead to recurrent symptoms, functional impairment, or a threatened limb.

An Updated Study to Determine Association between Gadolinium-Based Contrast Agents and Nephrogenic Systemic Fibrosis

Background

Nephrogenic systemic fibrosis (NSF) is a rare but serious disorder disease affecting patients with advanced renal disease. Although multiple studies have indicated an association between gadolinium-based contrast agents (GBCAs) and NSF, some studies published after 2007 found no association. We therefore performed a meta-analysis to evaluate the association and analyze related (co)factors.

Methods

Studies for analysis were identified by searching PubMed, Embase, and the Cochrane Central Register of Controlled Trials through December 2014. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using the fixed-effects model. Statistical heterogeneity was assessed by Q statistics and the I² test. Publication bias was evaluated using Begg’s test, Egger’s test, funnel plot, and classic fail-safe N. Study quality was assessed using the Newcastle-Ottawa Scale. We also conducted sensitivity analyses, subgroup analyses and a cumulative meta-analysis. All statistical analyses were performed using Comprehensive Meta-Analysis 2.0.

Results

A total of 14 studies (6,398 patients) met the inclusion criteria, but 3 were excluded since they reported no NSF events. Meta-analysis of controlled trials indicated a significant association between GBCAs and NSF development (OR = 16.504; 95% CI: 7.455–36.533; P < 0.001) and between gadodiamide and NSF (OR = 20.037; 95% CI: 3.725–107.784; P < 0.001). No statistical heterogeneity was observed across studies (P = 0.819, I² = 0%; P = 0.874, I² = 0%, respectively). Cumulative analysis demonstrated that the pooled ORs for association between GBCAs and NSF decreased post-2007 compared to pre-2007 (OR = 26.708; 95% CI: 10.273–69.436; P<0.001).

Conclusions

Although this updated meta-analysis found a significant association between GBCAs and the incidence of NSF in patients with advanced renal disease, the association decreased after 2007. More studies, especially randomized controlled trials, are warranted to examine the potential association between GBCAs other than gadodiamide and NSF.

Gadolinium and nephrogenic systemic fibrosis: an update

Nephrogenic systemic fibrosis (NSF) is a multisystem disease seen exclusively in patients with renal impairment. It can be severely debilitating and sometimes fatal. There is a strong association with gadolinium-based contrast agents used in magnetic resonance imaging (MRI). Risk factors include renal impairment and proinflammatory conditions, e.g. major surgery and vascular events. Although there is no single effective treatment for NSF, the most successful outcomes are seen following restoration of renal function, either following recovery from acute kidney injury or following renal transplantation. There have been ten biopsy-proved pediatric cases of NSF, with no convincing evidence that children have a significantly altered risk compared with the adult population. After implementation of guidelines restricting the use of gadolinium-based contrast agents in at-risk patients, there has been a sharp reduction in new cases and no new reports in children. Continued vigilance is recommended: screening for renal impairment, use of more stable gadolinium chelates, consideration of non-contrast-enhanced MRI or alternative imaging modalities where appropriate.

Incidence of nephrogenic systemic fibrosis in patients undergoing dialysis after contrast-enhanced magnetic resonance imaging with gadolinium-based contrast agents: the Prospective Fibrose Nephrogénique Systémique study

BACKGROUND

Nephrogenic systemic fibrosis (NSF) has been related to the use of gadolinium-based contrast agents (GBCAs) in patients undergoing dialysis. The Prospective Fibrose Nephrogénique Systémique study, a French prospective study supported by the French drug regulatory agency (Agence Nationale de Sécurité du Médicament) and the French Societies of Nephrology, Dermatology, and Radiology, aimed at determining the incidence of NSF in patients undergoing long-term dialysis.

MATERIALS AND METHODS

Adult patients undergoing long-term dialysis receiving a magnetic resonance imaging (MRI) examination prescribed between January 15, 2009 and May 31, 2011, with or without GBCA were included. The methodology was based on a patient form intended to detect any dermatological event (DE) that may occur within 4 months after the examination. Further investigations were planned with their physicians if a DE was reported.

RESULTS

A total of 571 patients were included. A total of 50.3% received GBCA. Among them, 93.4% received a macrocyclic GBCA, usually gadoteric acid (88.9%). All in all, 22 patients (3.9%) reported a DE. Dermatological diagnoses did not reveal any evidence of NSF.

CONCLUSIONS

The incidence of NSF after a single dose of a macrocyclic GBCA is null in our sample of 268 patients undergoing dialysis (hemodialysis and peritoneal dialysis). This incidence is just lower than 0.5%. When contrast-enhanced MRI can be essential, or even decisive, to the diagnosis, these results are important and reassuring if physicians need to perform contrast-enhanced MRI in patients undergoing dialysis.

Current status of nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF) occurs in patients with advanced chronic kidney disease (CKD) or acute renal failure, most commonly following exposure to gadolinium-based contrast agents (GBCAs). NSF can be debilitating and associated with increased mortality. The putative association of NSF with GBCAs prompted the development of guidelines to limit the use of these contrast agents in at-risk patients. Indeed, the incidence of NSF has decreased dramatically following application of these guidelines, which appears to be the only effective means of decreasing NSF incidence. Thus, increasing clinician awareness of these updated guidelines is important. The present review introduces and compares updated guidelines for GBCA use and discusses the latest advances in the understanding of the pathogenic mechanisms and treatment of NSF.

Nephrogenic systemic fibrosis in Denmark--a nationwide investigation

Background

Nephrogenic systemic fibrosis is a debilitating and painful disorder with an increased stimulation of the connective tissue in the skin and systemic tissues. The disease is associated with exposure to gadolinium-based contrast agent used in magnetic resonance imaging in patients with renal impairment.

Methods

The prevalence of nephrogenic systemic fibrosis has so far never been determined at a national level. In 2009, Denmark was the first country to design a guideline for the tracing of nephrogenic systemic fibrosis patients. The aim of this paper is to communicate the main findings of this quest.

Results

The outcome of the nationwide investigation revealed that Denmark had 65 patients with nephrogenic systemic fibrosis and thereby the highest prevalence of nephrogenic systemic fibrosis worldwide with 65 per 5.6 million inhabitants, or 12 per million.

Conclusions

The nationwide investigation in Denmark revealed the highest prevalence of NSF worldwide. This may be rooted in a high level of awareness of NSF both among doctors, politicians and, not least, the media, combined with the fact that a nationwide NSF investigation was initiated.

Fibrosis-associated single-nucleotide polymorphisms in TGFB1 and CAV1 are not associated with the development of nephrogenic systemic fibrosis

OBJECTIVE

To test the hypothesis that the subset of patients with impaired renal function who are exposed to gadolinium-containing contrast agents (GCCAs) and develop nephrogenic systemic fibrosis (NSF) have a genetic predisposition for disease.

METHODS

We examined whether an intronic single-nucleotide polymorphism (SNP) in caveolin-1 (CAV1 rs4730751) and 2 coding SNPs in transforming growth factor-beta 1 (TGFB1 rs1800471, codon 25; and rs1800470, codon 10) were associated with the NSF phenotype.

RESULTS

Forty-one patients with a history of chronic kidney disease and GCCA administration were studied, including NSF cases (n = 17) and control subjects (n = 24) without clinical or histological evidence of NSF. No significant differences in the genotype frequencies at these SNPs in TGFB1 and CAV1 were found between patients with NSF and subjects without NSF.

CONCLUSIONS

We conclude that polymorphisms in the genes encoding TGFB1 and CAV1 previously associated with the development and progression of fibrosis in several organ systems are not associated with development of NSF in this cohort of patients with renal impairment after GCCA exposure.